WorldWideScience

Sample records for delay enhanced mri

  1. Unexpected Coexisting Myocardial Infarction Detected by Delayed Enhancement MRI

    Directory of Open Access Journals (Sweden)

    Edouard Gerbaud

    2009-01-01

    Full Text Available We report a case of an unexpected coexisting anterior myocardial infarction detected by delayed enhancement MRI in a 41-year-old man following a presentation with a first episode of chest pain during inferior acute myocardial infarction. This second necrotic area was not initially suspected because there were no ECG changes in the anterior leads and the left descending coronary artery did not present any significant stenoses on emergency coronary angiography. Unrecognised myocardial infarction may carry important prognostic implications. CMR is currently the best imaging technique to detect unexpected infarcts.

  2. Myocardial delayed contrast enhancement in patients with arterial hypertension: Initial results of cardiac MRI

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Kjel [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: kjel_andersen@web.de; Hennersdorf, Marcus [Department of Cardiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: hennersdorf@med.uni-duesseldorf.de; Cohnen, Mathias [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: cohnen@med.uni-duesseldorf.de; Blondin, Dirk [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: blondin@med.uni-duesseldorf.de; Moedder, Ulrich [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: moedder@uni-duesseldorf.de; Poll, Ludger W. [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: poll@gmx.de

    2009-07-15

    Purpose: In arterial hypertension left ventricular hypertrophy comprises myocyte hypertrophy, interstitial fibrosis and structural alterations of the coronary microcirculation. MRI enables the detection of myocardial fibrosis, infarction and scar tissue by delayed enhancement (DE) after contrast media application. Aim of this study was to investigate patients with arterial hypertension but without known coronary disease or previous myocardial infarction to detect areas of DE. Methods and material: Twenty patients with arterial hypertension with clinical symptoms of myocardial ischemia, but without history of myocardial infarction and normal coronary arteries during coronary angiography were investigated on a 1.0 T superconducting magnet (Gyroscan T10-NT, Intera Release 8.0, Philips). Fast gradient-echo cine sequences and T2-weighted STIR-sequences were acquired. Fifteen minutes after injection of Gadobenate dimeglumine inversion recovery gradient-echo sequences were performed for detection of myocardial DE. Presence or absence of DE on MRI was correlated with clinical data and the results of echocardiography and electrocardiography, respectively. Results: Nine of 20 patients showed DE in the interventricular septum and the anteroseptal left ventricular wall. In 6 patients, DE was localized intramurally and in 3 patients subendocardially. There was a significant correlation between myocardial DE and ST-segment depressions during exercise and between DE and left-ventricular enddiastolic pressure. Patients with intermittent atrial fibrillation showed a myocardial DE more often than patients without atrial fibrillation. Conclusion: In our series, 45% of patients with arterial hypertension showed DE on cardiac MRI. In this clinical setting, delayed enhancement may be due to coronary microangiopathy. The more intramurally localization of DE, however, rather indicates myocardial interstitial fibrosis.

  3. Delayed enhancement imaging of myocardial viability: low-dose high-pitch CT versus MRI

    Energy Technology Data Exchange (ETDEWEB)

    Goetti, Robert; Feuchtner, Gudrun; Stolzmann, Paul; Donati, Olivio F.; Frauenfelder, Thomas; Leschka, Sebastian; Alkadhi, Hatem [University Hospital Zurich, Department of Radiology, Zurich (Switzerland); Wieser, Monika; Plass, Andre [University Hospital Zurich, Division of Cardiac and Vascular Surgery, Zurich (Switzerland)

    2011-10-15

    To evaluate the accuracy of high-pitch delayed enhancement (DE) CT for the assessment of myocardial viability with MRI as the reference standard. Twenty-four patients (mean age 66.9 {+-} 9.2 years) with coronary artery disease underwent DE imaging with 128-slice dual-source CT (prospective electrocardiography (ECG)-triggering) and MRI at 1.5 T. Two observers assessed DE transmurality per segment, and measured signal intensity (MRI) or attenuation (CT) in infarcted and healthy myocardium and noise in the left ventricular blood pool for calculating contrast-to-noise ratios (CNR). 75/408 (18.4%) segments in 18/24 patients (75.0%) showed DE in MRI, of which 28 segments in 10/24 (41.7%) patients were non-viable (scar tissue transmurality >50%). Sensitivity, specificity and accuracy of CT for diagnosis of non-viability were 60.7%, 96.8% and 94.4% per segment, and 90.0%, 92.9% and 91.7% per patient. CNR was significantly higher in MR (7.4 {+-} 3.0 vs. 4.6 {+-} 1.5; p = 0.018), and image noise significantly lower (11.6 {+-} 5.7 vs.15.0 {+-} 4.5; p = 0.019). Radiation dose of DECT was 0.89 {+-} 0.07 mSv. CTDE imaging in the high-pitch mode enables myocardial viability assessment at a low radiation dose and good accuracy compared with MR, although associated with a lower CNR and higher noise. (orig.)

  4. Time-delayed contrast-enhanced MRI improves detection of brain metastases: a prospective validation of diagnostic yield.

    Science.gov (United States)

    Cohen-Inbar, Or; Xu, Zhiyuan; Dodson, Blair; Rizvi, Tanvir; Durst, Christopher R; Mukherjee, Sugoto; Sheehan, Jason P

    2016-12-01

    The radiological detection of brain metastases (BMs) is essential for optimizing a patient's treatment. This statement is even more valid when stereotactic radiosurgery, a noninvasive image guided treatment that can target BM as small as 1-2 mm, is delivered as part of that care. The timing of image acquisition after contrast administration can influence the diagnostic sensitivity of contrast enhanced magnetic resonance imaging (MRI) for BM. Investigate the effect of time delayed acquisition after administration of intravenous Gadavist® (Gadobutrol 1 mmol/ml) on the detection of BM. This is a prospective IRB approved study of 50 patients with BM who underwent post-contrast MRI sequences after injection of 0.1 mmol/kg Gadavist® as part of clinical care (time-t0), followed by axial T1 sequences after a 10 min (time-t1) and 20 min delay (time-t2). MRI studies were blindly compared by three neuroradiologists. Single measure intraclass correlation coefficients were very high (0.914, 0.904 and 0.905 for time-t0, time-t1 and time-t2 respectively), corresponding to a reliable inter-observer correlation. The delayed MRI at time-t2 delayed sequences showed a significant and consistently higher diagnostic sensitivity for BM by every participating neuroradiologist and for the entire cohort (p = 0.016, 0.035 and 0.034 respectively). A disproportionately high representation of BM detected on the delayed studies was located within posterior circulation territories (compared to predictions based on tissue volume and blood-flow volumes). Considering the safe and potentially high yield nature of delayed MRI sequences, it should supplement the standard MRI sequences in all patients in need of precise delineation of their intracranial disease.

  5. Delayed-enhancement MRI of apical hypertrophic cardiomyopathy: assessment of the intramural distribution and comparison with clinical symptoms, ventricular arrhythmias, and cine MRI

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Yasuo; Fukushima, Yoshimitsu; Kumita, Shinichiro (Dept. of Radiology, Nippon Medical School, Tokyo (Japan)), email: yas-amano@nifty.com; Takayama, Morimasa (Dept. of Cardiology, Sakakibara Heart Inst., Tokyo (Japan)); Kitamura, Mitsunobu (Coronary Care Unit, Chiba-Hokuso Hospital of Nippon Medical School, Chiba (Japan))

    2011-07-15

    Background: Hypertrophic cardiomyopathy (HCM) is reported to show patchy midwall myocardial hyper enhancement on delayed-enhancement magnetic resonance imaging (DE-MRI). The intramural distribution of myocardial hyper enhancement and its correlation with clinical symptoms, ventricular arrhythmias, and cardiac function have not been described for symptomatic apical HCM. Purpose: To evaluate the features and significance of myocardial hyper enhancement on DE-MRI in symptomatic apical HCM. Material and Methods: Thirteen patients with symptomatic apical HCM and their 65 apical segments were investigated. Myocardial hyper enhancement and regional and global functional parameters were determined with MRI. We investigated the intramural distribution and frequencies of this myocardial hyper enhancement and compared them with the patients' clinical symptoms, the presence of ventricular arrhythmias, and cine MRI. Results: Eight (61.5%) patients with symptomatic apical HCM displayed apical myocardial hyper enhancement, and 22 (33.8%) of the 65 apical segments examined showed myocardial hyper enhancement. Of the myocardial hyper enhancement observed, 81.8% showed a subendocardial pattern.The Hyperenhanced apical myocardium had a lower percentage of systolic myocardial thickening, and was associated with serious symptoms (e.g. syncope) and ventricular arrhythmias. Conclusion: Patients with symptomatic apical HCM showed myocardial hyper enhancement involving the subendocardial layer, which might be related to regional systolic dysfunction, serious clinical symptoms, and ventricular arrhythmias

  6. Telmisartan in the diabetic murine model of acute myocardial infarction: dual contrast manganese-enhanced and delayed enhancement MRI evaluation of the peri-infarct region.

    Science.gov (United States)

    Toma, Ildiko; Kim, Paul J; Dash, Rajesh; McConnell, Michael V; Nishimura, Dwight; Harnish, Phillip; Yang, Phillip C

    2016-02-05

    A novel MRI technique, employing dual contrast manganese-enhanced MRI (MEMRI) and delayed enhancement MRI (DEMRI), can evaluate the physiologically unstable peri-infarct region. Dual contrast MEMRI-DEMRI enables comprehensive evaluation of telmisartan to salvage the peri-infarct injury to elucidate the underlying mechanism of restoring the ischemic cardiomyopathy in the diabetic mouse model. Dual contrast MEMRI-DEMRI was performed on weeks 1, 2, and 4 following initiation of telmisartan treatment in 24 left anterior descendent artery ligated diabetic mice. The MRI images were analyzed for core infarct, peri-infarct, left ventricular end-diastolic, end-systolic volumes, and the left ventricular ejection fraction (LVEF). Transmission electron microscopy (TEM) and real-time PCR were used for ex vivo analysis of the myocardium. Telmisartan vs. control groups demonstrated significantly improved LVEF at weeks 1, 2, and 4, respectively (33 ± 7 %*** vs. 19 ± 5 %, 29 ± 3 %*** vs. 22 ± 4 %, and 31 ± 2 %*** vs 18 ± 6 %, ***p Telmisartan group significantly salvaged the peri-infarct injury. The myocardial effects were validated by TEM, which confirmed the presence of the injured but viable cardiomyocyte morphology in the peri-infarct region and by flow cytometry of venous blood, which demonstrated significantly increased circulating endothelial progenitor cells (EPCs). The improved cardiac function in ischemic cardiomyopathy of diabetic mice by telmisartan is attributed to the attenuation of the peri-infarct injury by the angiogenic effects of EPCs to salvage the injured cardiomyocytes. Dual-contrast MEMRI-DEMRI technique tracked the therapeutic effects of telmisartan on the injured myocardium longitudinally.

  7. Patterns of delayed-enhancement in MRI of ischemic and non-ischemic cardiomyopathies; Muster der spaeten Kontrastmittelanreicherung in der MRT bei ischaemischen und nicht-ischaemischen Kardiomyopathien

    Energy Technology Data Exchange (ETDEWEB)

    Stork, A.; Bansmann, P.M.; Koops, A.; Adam, G. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany); Muellerleile, K.; Meinertz, T. [Universitaeres Herzzentrum, Universitaetsklinikum Hamburg-Eppendorf (Germany); Lund, G.K. [Kardiovaskulaere Bildgebung, Roentgeninstitut Duesseldorf (Germany)

    2007-01-15

    Contrast-enhanced MRI using the delayed-enhancement technique (DE-MRI) is widely applied in the clinical work-up of myocardial diseases. Myocardial diseases of varying etiology result in myocardial changes, such as necrosis, fibrosis, edema and metabolite deposition, which can be visualized by DE-MRI. Acute and chronic ischemic diseases based on a coronary artery disease as well as non-ischemic cardiomyopathies display DE. Cardiomyopathies often show a characteristic enhancement pattern. While ischemic lesions are localized in the subendocardium, non-ischemic cardiomyopathies often display an intramyocardial or subepicardial pattern. The typical pattern for dilated cardiomyopathies is band-like and intramyocardial with septal involvement. Arrhythmogenic right-ventricular dysplasias/cardiomyopathies are frequently associated with right-ventricular DE. In the case of amyloid cardiomyopathies which are often restrictive cardiomyopathies, subendocardial and circular DE is typically observed. Hypertrophic cardiomyopathies display patchy intramyocardial DE usually in the anteroseptal region. Acute myocarditis is typically accompanied by intramyocardial or subepicardial DE affecting the lateral wall. In the case of chronic myocarditis, intramyocardial or subepicardial DE is observed most frequently. Cardiac sarcoidosis typically entails patchy subepicardial DE with right- and left-ventricular involvement. Since there is an overlap between the enhancement patterns of cardiomyopathies, the diagnostic accuracy of DE-MRI is limited and the diagnosis must be based on additional clinical and MRI findings. The amount of DE often corresponds with cardiac functional parameters as well as with the frequency of cardiac events so that DE-MRI may be useful for risk stratification. Furthermore, DE-MRI can be helpful in the planning and evaluation of myocardial biopsies and electrophysiological examinations. (orig.)

  8. Association between delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and joint space narrowing and osteophytes

    DEFF Research Database (Denmark)

    Owman, H; Ericsson, Y B; Englund, M;

    2014-01-01

    OBJECTIVE: To examine the association between the relaxation time (T1Gd) of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and grade of tibiofemoral joint space narrowing (JSN) and osteophytosis 11 years later, in a cohort of meniscectomized patients. DESIGN: Patients...

  9. Integration of myocardial scar identified by preoperative delayed contrast-enhanced MRI into a high-resolution mapping system for planning and guidance of VT ablation procedures

    Science.gov (United States)

    Rettmann, M. E.; Suzuki, A.; Wang, S.; Pottinger, N.; Arter, J.; Netzer, A.; Parker, K.; Viker, K.; Packer, D. L.

    2017-03-01

    Myocardial scarring creates a substrate for reentrant circuits which can lead to ventricular tachycardia. In ventricular catheter ablation therapy, regions of myocardial scarring are targeted to interrupt arrhythmic electrical pathways. Low voltage regions are a surrogate for myocardial scar and are identified by generating an electro anatomic map at the start of the procedure. Recent efforts have focussed on integration of preoperative scar information generated from delayed contrast-enhanced MR imaging to augment intraprocedural information. In this work, we describe an initial feasibility study of integration of a preoperative MRI derived scar maps into a high-resolution mapping system to improve planning and guidance of VT ablation procedures.

  10. Assessment of the acute effects of glucocorticoid treatment on coronary microembolization using cine, first-pass perfusion, and delayed enhancement MRI.

    Science.gov (United States)

    Jin, Hang; Yun, Hong; Ma, Jian-ying; Chen, Zhang-wei; Chang, Shu-fu; Ge, Mei-ying; Zeng, Meng-su

    2016-04-01

    To assess the acute effects of methylprednisone treatment (MPT) on coronary microembolization (CME) by cardiac cine, first-pass perfusion, and delayed gadolinium enhancement magnetic resonance imaging (DE-MRI) in an experimental swine model. Microembolization was established by intracoronary infusion of microspheres into the left anterior artery. Swine received placebo (n = 12) or methylprednisolone (n = 10, 30 mg/kg) intravenously 30 minutes before microembolization. Perfusion and DE-MRI was performed 6 hours after microembolization. Cine MR images of pre-/post-CME were obtained using 1.5T scanner. Cine MRI demonstrated relative amelioration of the post-CME myocardial contractile dysfunction in the glucocorticoid-treated group compared to the placebo group (P < 0.001). Post-CME target myocardial perfusion parameters decreased in both groups after microembolization. The extent of these decreases were the same for the embolized-to-control area ratio of maximum upslope (P = 0.245; 95% confidence interval of the difference [CID], -0.041/0.148) and time to peak ratio (P = 0.122; 95% CID, -0.201/0.026); however, the maximum signal intensity was higher in the glucocorticoid-treated group (P = 0.012; 95% CID, 0.023/0.156). DE-MRI revealed patchy hyperenhancement in all placebo pigs (n = 12/12) after microembolization, but no hyperenhanced regions in the glucocorticoid-pretreated pigs (n = 0/10). Standard, readily available, cardiac MRI techniques are useful in demonstrating post-CME myocardial dysfunction and the acute effects of glucocorticoid treatment on CME. Glucocorticoid pretreatment improves myocardial contractile dysfunction, prevents hyperenhancement, and partially ameliorates the decline of myocardial perfusion in the embolized area. © 2015 Wiley Periodicals, Inc.

  11. Isolated right ventricular infarct presenting as ventricular fibrillation arrest and confirmed by delayed-enhancement cardiac MRI.

    Science.gov (United States)

    Cavalcante, João L; Al-Mallah, Mouaz; Hudson, Michael

    2010-10-01

    Malignant ventricular arrhythmias resulting from isolated right ventricular myocardial infarction (RVMI) without left ventricular myocardial ischaemia or infarction occur rarely. We present a case of a 61 year-old male with acute onset of chest pain and ventricular fibrillation cardiac arrest requiring prompt defibrillation. Subsequent 15-lead EKG, showed ST-segment elevation in the anterior and right precordial leads without ST-segment elevation in the inferior leads. Angiography documented occlusion of a large RV marginal branch. Delayed enhancement cardiac magnetic resonance imaging (DE-CMR) with gadolinium performed two days post-infarct showed isolated RVMI. Patient remained symptom free and haemodynamically stable throughout his hospital stay. The clinical presentation of isolated RV infarct can be misleading and diagnosis difficult. EKG findings can resemble acute anterior wall myocardial infarction, while its course can be accompanied by life-threatening ventricular arrhythmias. This case uniquely combines this rare clinical sequence with DE-CMR images using gadolinium to confirm isolated RVMI. A brief review of RVMI presentation and associated EKG patterns is also discussed.

  12. Delayed gadolinium-enhanced MRI of the meniscus (dGEMRIM) in patients with knee osteoarthritis: relation with meniscal degeneration on conventional MRI, reproducibility, and correlation with dGEMRIC

    Energy Technology Data Exchange (ETDEWEB)

    Tiel, Jasper van [University Medical Center, Department of Orthopaedic Surgery, Erasmus MC, Rotterdam (Netherlands); University Medical Center, Department of Radiology, Erasmus MC, P.O. Box 2040, Rotterdam (Netherlands); Kotek, Gyula; Krestin, Gabriel P.; Oei, Edwin H.G. [University Medical Center, Department of Radiology, Erasmus MC, P.O. Box 2040, Rotterdam (Netherlands); Reijman, Max; Bos, Pieter K.; Verhaar, Jan A.N. [University Medical Center, Department of Orthopaedic Surgery, Erasmus MC, Rotterdam (Netherlands); Bron, Esther E.; Klein, Stefan [University Medical Center, Department of Radiology, Erasmus MC, P.O. Box 2040, Rotterdam (Netherlands); University Medical Center, Department of Medical Informatics, Erasmus MC, Rotterdam (Netherlands); Weinans, Harrie [University Medical Center, Department of Orthopaedic Surgery, Erasmus MC, Rotterdam (Netherlands); Delft University of Technology, Department of Biomechanical Engineering, Delft (Netherlands); University Medical Center, Department of Orthopaedic Surgery, Utrecht (Netherlands); University Medical Center, Department of Rheumatology, Utrecht (Netherlands)

    2014-09-15

    To assess (1) whether normal and degenerated menisci exhibit different T1{sub GD} on delayed gadolinium-enhanced MRI of the meniscus (dGEMRIM), (2) the reproducibility of dGEMRIM and (3) the correlation between meniscus and cartilage T1{sub GD} in knee osteoarthritis (OA) patients. In 17 OA patients who underwent dGEMRIM twice within 7 days, meniscus and cartilage T1{sub GD} was calculated. Meniscus pathology was evaluated on conventional MRI. T1{sub GD} in normal and degenerated menisci were compared using a Student's t-test. Reproducibility was assessed using ICCs. Pearson's correlation was calculated between meniscus and cartilage T1{sub GD}. A trend towards lower T1{sub GD} in degenerated menisci (mean: 402 ms; 95 % CI: 359-444 ms) compared to normal menisci (mean: 448 ms; 95 % CI: 423-473 ms) was observed (p = 0.05). Meniscus T1{sub GD} ICCs were 0.85-0.90. The correlation between meniscus and cartilage T1{sub GD} was moderate in the lateral (r = 0.52-0.75) and strong in the medial compartment (r = 0.78-0.94). Our results show that degenerated menisci have a clear trend towards lower T1{sub GD} compared to normal menisci. Since these results are highly reproducible, meniscus degeneration may be assessed within one delayed gadolinium-enhanced MRI simultaneously with cartilage. The strong correlation between meniscus and cartilage T1{sub GD} suggests concomitant degeneration in both tissues in OA, but also suggests that dGEMRIC may not be regarded entirely as sulphated glycosaminoglycan specific. (orig.)

  13. Validation of 10-Minute Delayed Hepatocyte Phase Imaging with 30° Flip Angle in Gadoxetic Acid-Enhanced MRI for the Detection of Liver Metastasis.

    Directory of Open Access Journals (Sweden)

    Dahye Lee

    Full Text Available To compare 10-minute delayed hepatocyte phase imaging using a 30° flip angle (10 min-FA30 and 20-minute hepatocyte phase imaging using a 10° FA (20 min-FA10 in gadoxetic acid-enhanced MRI of patients with possible liver metastases, regarding lesion-to-liver contrast-to-noise ratio (CNR and focal hepatic lesion (FHL detection to evaluate whether 10 min-FA30 would be superior to 20 min-FA10.Eighty-three patients with 248 liver metastases and 78 benign FHLs who underwent gadoxetic acid-enhanced MRI with 10 min-FA30 and 20 min-FA10 were enrolled. Lesion-to-liver CNRs were compared between the two image groups. Two radiologists independently assessed the presence of FHLs using a four-point scale and detection sensitivity was calculated.The mean CNR for liver metastases on the 10 min-FA30 (248.5 ± 101.6 were significantly higher than that of the 20 min-FA10 (187.4 ± 77.4 (p < 0.001. The mean CNR difference between the two image groups was 61.2 ± 56.8. There was no significant difference in detection sensitivity of FHLs for two readers between 10 min-FA30 (mean 97.7% and 20 min-FA10 (mean 97.9%, irrespective of the lesion size or malignancy.10 min-FA30 yielded higher CNR with similar sensitivity compared to 20 min-FA10. This finding indicates that 10 min-FA30 can potentially replace 20 min-FA10 with higher diagnostic performance and save 10 minutes of time.

  14. Improved visualization of delayed perfusion in lung MRI

    Energy Technology Data Exchange (ETDEWEB)

    Risse, Frank [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Eichinger, Monika [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Semmler, Wolfhard [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Puderbach, Michael, E-mail: m.puderbach@dkfz.de [Department of Radiology, German Cancer Research Center, Heidelberg (Germany)

    2011-01-15

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S{sub n,max} normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement {tau} to visualize regions with delayed bolus onset; and (3) ratio R = S{sub n,max}/{tau} was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  15. Early assessment of sub-clinical cardiac involvement in systemic sclerosis (SSc) using delayed enhancement cardiac magnetic resonance (CE-MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Di Cesare, Ernesto, E-mail: ernesto.dicesare@cc.univaq.it [Department of Radiology, University of L’Aquila, Via Vetoio 1, 67100 L’Aquila (Italy); Battisti, Sara; Di Sibio, Alessandra [Department of Radiology, University of L’Aquila, Via Vetoio 1, 67100 L’Aquila (Italy); Cipriani, Paola; Giacomelli, Roberto; Liakouli, Vasiliky; Ruscitti, Piero [Rheumatology Clinic, Department of Internal Medicine and Public Health, University of L’Aquila, L’Aquila (Italy); Masciocchi, Carlo [Department of Radiology, University of L’Aquila, Via Vetoio 1, 67100 L’Aquila (Italy)

    2013-06-15

    Objectives: Systemic sclerosis heart involvement (SHI) is one of systemic sclerosis (SSc) most frequent complications, both in diffuse (dcSSc) and limited (lcSSc) cutaneous forms of disease. Nowadays, SHI is a major factor decreasing SSc survival rate because, when clinically evident, is associated with 70% of mortality at 5 years. SHI shows different forms, primary and/or secondary. Primary myocardial SHI is characterized by fibrosis. Aim of our study is to assess the presence and pattern of fibrosis as detected by cardiac magnetic resonance (CMR) in systemic sclerosis. Methods: In this study, we used CE-MRI (contrast enhanced-MRI) in 58 female SSc patients. Images were evaluated to obtain functional parameters and to see presence, location and pattern (nodular, linear or diffuse) of myocardial LE, sign of fibrosis. CE-MRI findings were correlated with patients clinical setting. Results: Myocardial fibrosis was detected in 25 of 58 patients (43%). The main finding observed in 16 of these 25 patients was a late enhancement showing a linear pattern, without coronary distribution and sparing the sub-endocardial myocardial layers. A patchy nodular enhancement pattern was observed in 9 patients (36%). Patients with linear pattern presented dcSSc, on the contrary patients with nodular LE displayed the lcSSc form. Conclusions: This study shows that CE-MRI is a reliable technique to detect SHI earlier than other methods. SHI increase passive myocardial stiffness, proportional to collagen deposition degree, leading to cardiac remodelling with possible development of heart failure, even with normal ejection fraction. An early treatment of SHI might improve SSc patients outcome.

  16. Estimation of contrast agent bolus arrival delays for improved reproducibility of liver DCE MRI

    Science.gov (United States)

    Chouhan, Manil D.; Bainbridge, Alan; Atkinson, David; Punwani, Shonit; Mookerjee, Rajeshwar P.; Lythgoe, Mark F.; Taylor, Stuart A.

    2016-10-01

    Delays between contrast agent (CA) arrival at the site of vascular input function (VIF) sampling and the tissue of interest affect dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling. We investigate effects of altering VIF CA bolus arrival delays on liver DCE MRI perfusion parameters, propose an alternative approach to estimating delays and evaluate reproducibility. Thirteen healthy volunteers (28.7  ±  1.9 years, seven males) underwent liver DCE MRI using dual-input single compartment modelling, with reproducibility (n  =  9) measured at 7 days. Effects of VIF CA bolus arrival delays were assessed for arterial and portal venous input functions. Delays were pre-estimated using linear regression, with restricted free modelling around the pre-estimated delay. Perfusion parameters and 7 days reproducibility were compared using this method, freely modelled delays and no delays using one-way ANOVA. Reproducibility was assessed using Bland-Altman analysis of agreement. Maximum percent change relative to parameters obtained using zero delays, were  -31% for portal venous (PV) perfusion, +43% for total liver blood flow (TLBF), +3247% for hepatic arterial (HA) fraction, +150% for mean transit time and  -10% for distribution volume. Differences were demonstrated between the 3 methods for PV perfusion (p  =  0.0085) and HA fraction (p  liver DCE MRI quantification. Pre-estimation of delays with constrained free modelling improved 7 days reproducibility of perfusion parameters in volunteers.

  17. Comparison of visual scoring and quantitative planimetry methods for estimation of global infarct size on delayed enhanced cardiac MRI and validation with myocardial enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Mewton, Nathan, E-mail: nmewton@gmail.com [Hopital Cardiovasculaire Louis Pradel, 28, Avenue Doyen Lepine, 69677 Bron cedex, Hospices Civils de Lyon (France); CREATIS-LRMN (Centre de Recherche et d' Applications en Traitement de l' Image et du Signal), Universite Claude Bernard Lyon 1, UMR CNRS 5220, U 630 INSERM (France); Revel, Didier [Hopital Cardiovasculaire Louis Pradel, 28, Avenue Doyen Lepine, 69677 Bron cedex, Hospices Civils de Lyon (France); CREATIS-LRMN (Centre de Recherche et d' Applications en Traitement de l' Image et du Signal), Universite Claude Bernard Lyon 1, UMR CNRS 5220, U 630 INSERM (France); Bonnefoy, Eric [Hopital Cardiovasculaire Louis Pradel, 28, Avenue Doyen Lepine, 69677 Bron cedex, Hospices Civils de Lyon (France); Ovize, Michel [Hopital Cardiovasculaire Louis Pradel, 28, Avenue Doyen Lepine, 69677 Bron cedex, Hospices Civils de Lyon (France); INSERM Unite 886 (France); Croisille, Pierre [Hopital Cardiovasculaire Louis Pradel, 28, Avenue Doyen Lepine, 69677 Bron cedex, Hospices Civils de Lyon (France); CREATIS-LRMN (Centre de Recherche et d' Applications en Traitement de l' Image et du Signal), Universite Claude Bernard Lyon 1, UMR CNRS 5220, U 630 INSERM (France)

    2011-04-15

    Purpose: Although delayed enhanced CMR has become a reference method for infarct size quantification, there is no ideal method to quantify total infarct size in a routine clinical practice. In a prospective study we compared the performance and post-processing time of a global visual scoring method to standard quantitative planimetry and we compared both methods to the peak values of myocardial biomarkers. Materials and methods: This study had local ethics committee approval; all patients gave written informed consent. One hundred and three patients admitted with reperfused AMI to our intensive care unit had a complete CMR study with gadolinium-contrast injection 4 {+-} 2 days after admission. A global visual score was defined on a 17-segment model and compared with the quantitative planimetric evaluation of hyperenhancement. The peak values of serum Troponin I (TnI) and creatine kinase (CK) release were measured in each patient. Results: The mean percentage of total left ventricular myocardium with hyperenhancement determined by the quantitative planimetry method was (20.1 {+-} 14.6) with a range of 1-68%. There was an excellent correlation between quantitative planimetry and visual global scoring for the hyperenhancement extent's measurement (r = 0.94; y = 1.093x + 0.87; SEE = 1.2; P < 0.001) The Bland-Altman plot showed a good concordance between the two approaches (mean of the differences = 1.9% with a standard deviation of 4.7). Mean post-processing time for quantitative planimetry was significantly longer than visual scoring post-processing time (23.7 {+-} 5.7 min vs 5.0 {+-} 1.1 min respectively, P < 0.001). Correlation between peak CK and quantitative planimetry was r = 0.82 (P < 0.001) and r = 0.83 (P < 0.001) with visual global scoring. Correlation between peak Troponin I and quantitative planimetry was r = 0.86 (P < 0.001) and r = 0.85 (P < 0.001) with visual global scoring. Conclusion: A visual approach based on a 17-segment model allows a rapid

  18. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) of cadaveric shoulders: comparison of contrast dynamics in hyaline and fibrous cartilage after intraarticular gadolinium injection.

    Science.gov (United States)

    Wiener, E; Hodler, J; Pfirrmann, C W A

    2009-01-01

    Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Transverse T(1) maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T(1) maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. T(1) of unenhanced hyaline cartilage of the glenoid was 568+/-34 ms. T(1) of unenhanced fibrous cartilage of the labrum was 552+/-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T(1)(Gd) values in fibrous cartilage. T(1) and triangle Delta R(1) values of hyaline and fibrous cartilage after 2.5 hours were 351+/-16 ms and 1.1+/-0.09 s(-1), and 332+/-31 ms and 1.2+/-0.1 s(-1), respectively. A significant decrease in T(1)(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium.

  19. Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) of Cadaveric Shoulders: Comparison of Contrast Dynamics in Hyaline and Fibrous Cartilage after Intraarticular Gadolinium Injection

    Energy Technology Data Exchange (ETDEWEB)

    Wiener, E. (Dept. of Radiology, Charite Universitaetsmedizin Berlin (Germany)); Hodler, J.; Pfirrmann, C.W.A. (Dept. of Radiology, Orthopedic Univ. Hospital Balgrist, Zuerich (Switzerland))

    2009-01-15

    Background: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a novel method to investigate cartilaginous and fibrocartilaginous structures. Purpose: To investigate the contrast dynamics in hyaline and fibrous cartilage of the glenohumeral joint after intraarticular injection of gadopentetate dimeglumine. Material and Methods: Transverse T1 maps were acquired on a 1.5T scanner before and after intraarticular injection of 2.0 mmol/l gadopentetate dimeglumine in five cadaveric shoulders using a dual flip angle three-dimensional gradient echo (3D-GRE) sequence. The acquisition time for the T1 maps was 5 min 5 s for the whole shoulder. Measurements were repeated every 15 min over 2.5 hours. Regions of interest (ROIs) covering the glenoid cartilage and the labrum were drawn to assess the temporal evolution of the relaxation parameters. Results: T1 of unenhanced hyaline cartilage of the glenoid was 568+-34 ms. T1 of unenhanced fibrous cartilage of the labrum was 552+-38 ms. Significant differences (P=0.002 and 0.03) in the relaxation parameters were already measurable after 15 min. After 2 to 2.5 hours, hyaline and fibrous cartilage still demonstrated decreasing relaxation parameters, with a larger range of the T1(Gd) values in fibrous cartilage. T1 and ?R1 values of hyaline and fibrous cartilage after 2.5 hours were 351+-16 ms and 1.1+-0.09/s, and 332+-31 ms and 1.2+-0.1/s, respectively. Conclusion: A significant decrease in T1(Gd) was found 15 min after intraarticular contrast injection. Contrast accumulation was faster in hyaline than in fibrous cartilage. After 2.5 hours, contrast accumulation showed a higher rate of decrease in hyaline cartilage, but neither hyaline nor fibrous cartilage had reached equilibrium

  20. Gd-BOPTA增强60min再延迟扫描对小肝癌的诊断价值%Evaluation of delayed enhanced MRI with Gd-BOPTA in diagnosis of small HCC

    Institute of Scientific and Technical Information of China (English)

    吕涵青; 陈健湘; 谢宗贵; 赵波沣

    2011-01-01

    Objective To investigate the diagnostic value of 60 minutes delayed enhanced MR imaging with Gd- BOPTA, a double- phasic magnetic resonance contrast agent, on the small hepatocellular cacinoma (SHCC).Methods Twenty- five patients with surgery or pathologically proved SHCC underwent MR scan with PHILIPS Intera the 1.5T magnetic resonance scanner.The scan included SE T1WI, FSE T2WI and Gd- BOPTA dynamic enhanced MRI.Dynamic enhanced scanning were done 20 seconds, 1,5 and 60 minutes after Gd- BOPTA injection using THRIVE sequence.The signal intensity of lesions on non- enhanced, dynamic and 60 minutes delayed enhanced MR imaging were observed and analyzed.Results In 25 patients with SHCC, 33 lesions were found.The detection rate ofnon- enhanced, dynamic and 60 minutes delayed enhanced MR imaging were 75.8%, 81.8% and 96.9%, respectively.There was significant difference between 60 minutes delayed enhanced MR imaging and dynamic enhanced MR imaging.Conclusion Gd- BOPTA has an important role in the diagnosis of SHCC, especially to find SHCC of deficient blood supply using 60 minutes delayed enhanced MR imaging.%目的 探讨具有双相增强作用的磁共振对比剂钆贝葡胺(Gd-BOPTA),MRI增强后60 min再延迟扫描对小肝癌(SHCC)的诊断价值.方法 手术或穿刺病理证实为SHCC患者25例,采用Philips Intera 1.5 T磁共振扫描仪.行SE序列T1WI、FSE序列T2WI及Gd-BOPTA快速动态增强多期扫描.Gd-BOPTA增强扫描采用静脉团注快速动态增强扫描,并在团注后20 s、1 min、5 min及60 min行THRIVE扫描.观察分析MRI平扫、Gd-BOPTA三期增强扫描及60 min再延迟扫描病灶的信号改变,并进行统计学处理.结果 25例患者,共发现SHCC病灶33个;对SHCC病灶的检出率,MRI平扫为75.8%(25/33),Gd-BOPTA三期增强为81.8%(27/33),Gd-BOPTA三期增强+60 min再延迟扫描为96.9%(32/33).Gd-BOPTA三期增强联合60 min再延迟扫描对SHCC病灶的检出率明显优于Gd-BOPTA三期增强,两者之

  1. MR delayed enhancement imaging findings in suspected acute myocarditis

    Energy Technology Data Exchange (ETDEWEB)

    Gahide, Gerald [CHU de Montpellier, Radiologie centrale - Pole Cardiovasculaire et Thoracique, Montpellier (France); Centre Hospitalo-Universitaire de Montpellier, Hopital A de Villeneuve, Montpellier (France); Bertrand, D.; Dacher, J.N. [CHU de Rouen, Radiologie centrale - Hopital Charles Nicolle, Rouen (France); Roubille, F.; Skaik, S.; Piot, C.; Leclerq, F. [CHU de Montpellier, Departement de Cardiologie - Pole Cardiovasculaire et Thoracique, Montpellier (France); Tron, C.; Cribier, A. [CHU de Rouen, Departement de Cardiologie - Hopital Charles Nicolle, Rouen (France); Vernhet, H. [CHU de Montpellier, Radiologie centrale - Pole Cardiovasculaire et Thoracique, Montpellier (France)

    2010-01-15

    The purpose of the study was to prospectively assess the clinical impact of routinely performed delayed enhancement imaging in suspected acute myocarditis. A two-centre prospective study was performed in patients with suspected acute myocarditis. The protocol included horizontal long axis, vertical long axis and short axis cine MR and delayed enhancement imaging after Gd-DTPA infusion (0.2 mmol/kg). Sixty consecutive patients were enrolled (aged 49.4{+-}17.8 years). MRI demonstrated delayed enhancement sparing the subendocardicardial layer in 51.6% of patients, concordant with the diagnosis of acute myocarditis; 16.7% of patients exhibited delayed enhancement involving the subendocardial layer with irregular margins, concordant with the diagnosis of acute myocardial infarction; 31.7% of patients had delayed enhancement imaging that was considered normal. Routine imaging to identify delayed enhancement provided crucial information in suspected acute myocarditis by reinforcing the diagnosis in 51.6% of patients and correcting a misdiagnosed acute myocardial infarction in 16.7% of patients. (orig.)

  2. Delayed gadolinium-enhanced MRI of cartilage and T2 mapping for evaluation of reparative cartilage-like tissue after autologous chondrocyte implantation associated with Atelocollagen-based scaffold in the knee

    Energy Technology Data Exchange (ETDEWEB)

    Tadenuma, Taku; Uchio, Yuji; Kumahashi, Nobuyuki; Iwasa, Junji [Shimane University School of Medicine, Department of Orthopaedic Surgery, Izumo-shi, Shimane-ken (Japan); Fukuba, Eiji; Kitagaki, Hajime [Shimane University School of Medicine, Department of Radiology, Izumo-shi, Shimane-ken (Japan); Ochi, Mitsuo [Hiroshima University, Department of Orthopaedic Surgery, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Minami-ku, Hiroshima (Japan)

    2016-10-15

    To elucidate the quality of tissue-engineered cartilage after an autologous chondrocyte implantation (ACI) technique with Atelocollagen gel as a scaffold in the knee in the short- to midterm postoperatively, we assessed delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) and T2 mapping and clarified the relationship between T1 and T2 values and clinical results. In this cross-sectional study, T1 and T2 mapping were performed on 11 knees of 8 patients (mean age at ACI, 37.2 years) with a 3.0-T MRI scanner. T1{sub implant} and T2{sub implant} values were compared with those of the control cartilage region (T1{sub control} and T2{sub control}). Lysholm scores were also assessed for clinical evaluation. The relationships between the T1 and T2 values and the clinical Lysholm score were also assessed. There were no significant differences in the T1 values between the T1{sub implant} (386.64 ± 101.78 ms) and T1{sub control} (375.82 ± 62.89 ms) at the final follow-up. The implants showed significantly longer T2 values compared to the control cartilage (53.83 ± 13.89 vs. 38.21 ± 4.43 ms). The postoperative Lysholm scores were significantly higher than the preoperative scores. A significant correlation was observed between T1{sub implant} and clinical outcomes, but not between T2{sub implant} and clinical outcomes. Third-generation ACI implants might have obtained an almost equivalent glycosaminoglycan concentration compared to the normal cartilage, but they had lower collagen density at least 3 years after transplantation. The T1{sub implant} value, but not the T2 value, might be a predictor of clinical outcome after ACI. (orig.)

  3. The value of delayed phase enhanced imaging in malignant pleural mesothelioma

    Science.gov (United States)

    Patel, Akash M.; Berger, Ian; Wileyto, E. Paul; Khalid, Urooj; Torigian, Drew A.; Nachiappan, Arun C.; Barbosa, Eduardo M.; Gefter, Warren B.; Galperin-Aizenberg, Maya; Gupta, Narainder K.; Simone, Charles B.; Haas, Andrew R.; Alley, Evan W.; Singhal, Sunil; Cengel, Keith A.

    2017-01-01

    Background Cross-sectional imaging of malignant pleural mesothelioma (MPM) can underestimate the presence of local tumor invasion. Since accurate staging is vital optimal choice of therapy, techniques that optimize pleural imaging are needed. Here we estimate the optimal timing of MPM enhancement on magnetic resonance imaging (MRI). Methods All MPM patients with intravenous (IV) contrast enhanced staging MRI between 2000–2016 at our institution were retrospectively selected for image analysis. Patients with incomplete imaging protocol and maximum pleural tumor thickness 80%, >85%, and >90% peak tumor enhancement. There was a statistically significant correlation between increasing tumor enhancement and subjective lesion conspicuity. Conclusions Optimal MPM enhancement on MRI likely occurs at a time delay between 2.5–5 min following IV contrast administration. Further study of delayed phase enhancement of MPM with dynamic contrast enhanced MRI is warranted. PMID:28932538

  4. Sturge-Weber syndrome with no leptomeningeal enhancement on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Fischbein, N.J.; Barkovich, A.J. [Department of Radiology, San Francisco, CA (United States); Wu, Y.; Berg, B.O. [Department Pediatric Neurology, University of California, San Francisco, California (United States)

    1998-03-01

    Sturge-Weber syndrome (SWS) is a neurocutaneous syndrome characterized by a facial nevus flammeus associated with seizures, developmental delay, and, often, with hemiparesis and hemianopia. On MRI, the most characteristic finding has been reported to be leptomeningeal enhancement, believed to represent leakage of contrast medium through the anomalous pial vessels that characterize the disease. We present a case of SWS with no evidence of leptomeningeal enhancement. This case illustrates that leptomeningeal enhancement need not be present in SWS, and the absence of this characteristic finding does not preclude the diagnosis. (orig.) With 2 figs.

  5. Late Adverse Events after Enhanced and Unenhanced MRI and CT

    DEFF Research Database (Denmark)

    Azzouz, Manal; Rømsing, Janne; Thomsen, Henrik S.

    2014-01-01

    of LAEs was significantly higher in the enhanced MRI (38%) and CT (27%) groups than unenhanced MRI (20%) and CT (16%) groups. The frequency of nausea, dizziness, abdominal pain and diarrhoea was significantly higher in the enhanced MRI group than in the MRI control group, while taste sensation...

  6. Comparison of Delayed Gadolinium-Enhanced MRI with Magnetization Transfer after Injection of Single-Dose and Immediate Image without MT after Injection of Double Dose Gadolinium Chelates for Detecting

    Directory of Open Access Journals (Sweden)

    Ahmad Alizadeh

    2010-05-01

    Full Text Available Background/Objective: To determine whether the use of single dose gadolinium chelate in combination of MTC and delay of 20-30 minute brain imaging is useful in detecting MS lesions."nPatients and Methods: T1W spin echo images with and without MTC were obtained before contrast administration followed by T1W images with MTC starting and 20-30 minutes after contrast administration. After 24-72 hours T1W images without MTC were obtained immediately after injection of 0.2 mmol/Kg contrast material. All images were evaluated in a blinded route by two readers. Outcome parameters included the number of enhancing lesions."nResults: Single dose in combination with MTC and delay of 20-30 minutes showed 16 enhancing lesions and double dose showed 44. Differences between the two methods were significant (p=0.003. Thirteen lesions enhanced with both methods."nConclusion: The use of single dose in combination with MTC and delay of 20-30 minutes enables us to detect an increase of enhancing lesions."nKeywords: Magnetic Resonance, Magnetization Transfer, Multiple Sclerosis, Delay

  7. Fusion of Delayed-enhancement MR Imaging and Contrast-enhanced MR Angiography to Visualize Radiofrequency Ablation Scar on the Pulmonary Vein.

    Science.gov (United States)

    Shigenaga, Yutaka; Kiuchi, Kunihiko; Ikeuchi, Kazushi; Ikeda, Takayuki; Okajima, Katsunori; Yasaka, Yoshinori; Kawai, Hiroya

    2015-01-01

    Delayed-enhancement magnetic resonance imaging (DE-MRI) is reported to detect the radiofrequency (RF) ablation scar of pulmonary vein isolation. However, the precise localization of RF scar is difficult to recognize due to the poor anatomical information of the 3-dimensionally reconstructed DE-MRI. We report 2 cases in which fusion of DE-MRI and contrast-enhanced MR angiography facilitated the identification of RF scar, and we detail our fusion method.

  8. A unique pattern of delayed enhancement of a large cardiac fibroma on magnetic resonance imaging.

    Science.gov (United States)

    El Yaman, Malek M; Vos, Jeffrey A; Gustafson, Robert A

    2015-06-01

    MRI is a valuable noninvasive tool that helps in predicting the type of cardiac tumors and guiding management decisions. Several reports have described the appearance of cardiac fibromas on MRI, which typically show hyperenhancement on myocardial delayed enhancement (MDE) imaging, with or without a dark core. This report demonstrates the unique appearance of a large solitary ventricular septal cardiac fibroma in a 5-month-old patient on MDE imaging, with two discrete dark cores, each surrounded by a hyperenhancing pseudocapsule.

  9. Prostatic Cancer: Diagnosis and Differentiation by Dynamic Contrast-Enhanced MRI

    Institute of Scientific and Technical Information of China (English)

    SHIHao; DINGHongyu; ZHANGGuangying; YANGZhenzhen

    2005-01-01

    Objective: To assess the role of dynamic contrast-enhanced MRI (DCE-MRI) in the diagnosis and differentiation of prostatic cancer (PC). Methods: Five volunteers, 36 patients with benign prostatic hyperplasia (BPH) and 13 patients with biopsy-proven prostate cancer underwent conventional MRI, DCE-MR1 and delayed enhancement MRI. The value of the signal intensity in DCE-MRI was measured and calculated to draw the time-signal intensity curve of the normal peripheral zone (PZ), the prostate cancer and the benign prostatic hyperplasia. Results: In DCE-MRI, the normal peripheral zone was enhanced mildly and slowly and the peak value was located in late phase. The enhancement of the lesions in 36 patients with the benign prostatic hyperplasia was obvious in early phase and strengthened gradually, and then turned to decrease in late phase after peak value. The lesions in 9 of 13 cases with prostate cancer were enhanced obviously in early phase and washed out rapidly, and the peak value was located in early phase, but the peak value was in mediate and late phase in the other 4 cases with diffuse lesion in the prostate on T2WI. Conclusion: In DCE-MRI, the enhancement patterns of the normal peripheral zone,the prostate cancer and the benign prostatic hyperplasia were significantly different. DCE-MRI was very useful in the diagnosis and differentiation of prostate cancer.

  10. Gd enhanced MRI in sensorineural hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, Mika; Tono, Tetsuya; Toyama, Katsuhiro; Kano, Kiyo; Morimitsu, Tamotsu [Miyazaki Medical Coll., Kiyotake (Japan)

    1996-09-01

    The enhanced MRI hearing findings of the inner ear in 124 patients with sensorineural hearing loss were evaluated. MR images were obtained before and after the intravenous administration of gadolinium (0.1 mmol/kg). In three out of seventy-nine patients with unilateral healing loss, cochlear and/or the vestibular enhancement was noted on the symptomatic side. The positive cases included those with Ramsay-Hunt syndrome, mumps and so-called sudden deafness. Forty-five patients with bilateral hearing loss showed no enhancement within the inner ear. Although positive gadolinium enhancement of the inner ear may detect inflammatory lesions due to a viral infection, its incidence in sensorineural hearing loss, including cases of sudden deafness. seems to be extremely rare. (author)

  11. Dynamic contrast enhanced MRI in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Alonzi, Roberto [Marie Curie Research Wing, Mount Vernon Cancer Centre, Rickmansworth Road, Northwood, Middlesex, HA6 2RN (United Kingdom)], E-mail: robertoalonzi@btinternet.com; Padhani, Anwar R. [Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Rickmansworth Road, Northwood, Middlesex, HA6 2RN (United Kingdom); Synarc Inc. 575 Market Street, San Francisco, CA 94105 (United States)], E-mail: anwar.padhani@paulstrickland-scannercentre.org.uk; Allen, Clare [Department of Imaging, University College Hospital, London, 235 Euston Road, NW1 2BU (United Kingdom)], E-mail: clare.allen@uclh.nhs.uk

    2007-09-15

    Angiogenesis is an integral part of benign prostatic hyperplasia (BPH), is associated with prostatic intraepithelial neoplasia (PIN) and is key to the growth and for metastasis of prostate cancer. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) using small molecular weight gadolinium chelates enables non-invasive imaging characterization of tissue vascularity. Depending on the technique used, data reflecting tissue perfusion, microvessel permeability surface area product, and extracellular leakage space can be obtained. Two dynamic MRI techniques (T{sub 2}*-weighted or susceptibility based and T{sub 1}-weighted or relaxivity enhanced methods) for prostate gland evaluations are discussed in this review with reference to biological basis of observations, data acquisition and analysis methods, technical limitations and validation. Established clinical roles of T{sub 1}-weighted imaging evaluations will be discussed including lesion detection and localisation, for tumour staging and for the detection of suspected tumour recurrence. Limitations include inadequate lesion characterisation particularly differentiating prostatitis from cancer, and in distinguishing between BPH and central gland tumours.

  12. Hepatocellular carcinoma: perfusion quantification with dynamic contrast-enhanced MRI

    NARCIS (Netherlands)

    Taouli, B.; Johnson, R.S.; Hajdu, C.H.; Oei, M.T.H.; Merad, M.; Yee, H.; Rusinek, H.

    2013-01-01

    The objective of our study was to report our initial experience with dynamic contrast-enhanced MRI (DCE-MRI) for perfusion quantification of hepatocellular carcinoma (HCC) and surrounding liver.DCE-MRI of the liver was prospectively performed on 31 patients with HCC (male-female ratio, 26:5; mean ag

  13. Can unenhanced multiparametric MRI substitute gadolinium-enhanced MRI in the characterization of vertebral marrow infiltrative lesions?

    Directory of Open Access Journals (Sweden)

    Dalia Z. Zidan

    2014-06-01

    Conclusion: Unenhanced-multiparametric MRI is compatible with gadolinium-enhanced MRI in reliable characterization of marrow infiltrative lesions. The routine MRI protocol of cancer patients should be altered to accommodate the evolving MRI technology and cost effectively substitute the need for a gadolinium enhanced scan.

  14. Clinical experiences of delayed contrast enhancement with cardiac computed tomography: case series

    Directory of Open Access Journals (Sweden)

    Sidhu Manavjot S

    2013-01-01

    Full Text Available Abstract Background Myocardial delayed enhancement (MDE by gadolinium-enhanced cardiac MRI is well established for myocardial scar assessment in ischemic and non-ischemic heart disease. The role of MDE by cardiac CT (CT-MDE is not yet defined. Findings We reviewed all clinical cases of CT-MDE at a tertiary referral center to present the cases as a case series. All clinical cardiac CT exams which utilized CT-MDE imaging between January 1, 2005 and October 1, 2010 were collected as a series and their findings were also compared with available myocardial imaging to assess for myocardial abnormalities, including echocardiography (wall motion, morphology, cardiac MRI (delayed enhancement, morphology, SPECT MPI (perfusion defects. 5,860 clinical cardiac CT exams were performed during the study period. CT-MDE was obtained in 18 patients and was reported to be present in 9 patients. The indications for CT-MDE included ischemic and non-ischemic heart diseases. In segments positive for CT-MDE, there was excellent agreement of CT with other modalities: echocardiography (n=8 demonstrated abnormal morphology and wall motion (k=1.0 and k=0.82 respectively; prior MRI (n=2 demonstrated abnormal delayed enhancement (MR-MDE (k=1.0; SPECT MPI (n=1 demonstrated fixed perfusion defects (k=1.0. In the subset of patients without CT-MDE, no abnormal segments were identified by echocardiography (n=8, MRI (n=1 and nuclear MPI (n=0. Conclusions CT-MDE was performed in rare clinical situations. The indications included both ischemic and non-ischemic heart disease and there was an excellent agreement between CT-MDE and abnormal myocardium by echocardiography, cardiac MRI, and nuclear MPI.

  15. [Study on cine view of relative enhancement ratio map in O2-enhanced MRI].

    Science.gov (United States)

    Fujii, Keita; Watanabe, Yasushi; Hanaoka, Shouhei; Motoyoshi, Kouichi; Goto, Masami; Amemiya, Shiori; Ino, Kenji; Akahane, Masaaki; Yano, Keiichi; Ohtomo, Kuni

    2014-11-01

    Magnetic resonance imaging (MRI) enables the evaluation of organ structure and function. Oxygen-enhanced MRI (O2-enhanced MRI) is a method for evaluating the pulmonary ventilation function using oxygen as a contrast agent. We created the Cine View of Relative Enhancement Ratio Map (Cine RER map) in O2-enhanced MRI to easily observe the contrast effect for clinical use. Relative enhancement ratio (RER) was determined as the pixel values of the Cine RER map. Moreover, six healthy volunteers underwent O2-enhanced MRI to determine the appropriate scale width of the Cine RER map. We calculated each RER and set 0 to 1.27 as the scale width of the Cine RER map based on the results. The Cine RER map made it possible to observe the contrast effect over time and thus is a convenient tool for evaluating the pulmonary ventilation function in O2-enhanced MRI.

  16. Quantitative MRI analysis of dynamic enhancement of focal liver lesions

    Directory of Open Access Journals (Sweden)

    S. S. Bagnenko

    2012-01-01

    Full Text Available In our study 45 patients with different focal liver lesions (110 nodules were examined using high field MR-system (1,5 T. During this investigation quantitative MRI analysis of dynamic enhancement of various hepatic lesions and parenchymatous organs of abdomen were performed. It was shown that quantitative evaluation of enhanced MRI improves understanding of vascular transformation processes in pathologic hepatic focuses and in liver itself that is important for differential diagnoses of these diseases.

  17. RETROSPECTIVE ANALYSIS OF MAGNETIC RESONANCE MYOCARDIAL DELAYED ENHANCEMENT

    Institute of Scientific and Technical Information of China (English)

    Zhu-hua Zhang; Lin-yan Kong; Feng Feng; Hui You; Hong-yi Sun; Wen-min Zhao; Li-ren Zhang; Zheng-yu Jin; Qi Miao; Song-bai Lin; Shu-yang Zhang; Dong-jing Li; Li-bo Chen; Heng Zhang; Yi-ning Wang; Lu Zhou

    2006-01-01

    Objective To explore the imaging and related clinical characteristics of magnetic resonance (MR) delayed enhancement in patients with ischemic or nonischemic heart disease.Methods Thirty-two cases who underwent MR myocardial cine and delayed enhancement imaging from January 2004 to October 2006 were retrospectively analyzed.The cine sequence imaging included the four-chamber view and the left ventricular short axis view.The delayed enhancement imaging was taken 10 minutes after the infusion of gadolinium from the antecubital vein with a segmented inversion-recovery-prepared T1-weighted fast gradient echo sequence.Patients underwent coronary computed tomography angiography (CTA) two weeks before or after the MR imaging examination.Combined with clinical history,the clinical and MR imaging characteristics of the patients who had delayed enhancement were analyzed.Results MR delayed enhancement could be found in 16 cases.Among them,12 cases had ischemic heart disease.Their coronary CTA showed one to three vessel diseases.The delayed enhancement was transmural or subendocardium,and the area of delayed enhancement corresponded well with one or more coronary arteries which had severe stenosis or occlusion.Four cases had nonischemic heart diseases.One case was dilated cardiomyopathy,with diffuse small midwall spots in delayed enhancemen and only 30% stenosis of the anterior descending coronary artery in coronary CTA.One case was hypertrophic cardiomyopathy,with delayed enhancement of strip- and patch-shaped at midwall of the hypertrophic myocardium.One case was restrictive cardiomyopathy,and the delayed enhancement was located in the area of subendocardium of both the right and left ventricles.Coronary CTA of these two cases were normal.The other case was a mass of the lateral wall of the left ventricle,and the delayed enhancement with a clumpy shape was located in the lateral wall of the left ventricle.Conclusions MR myocardial delayed enhancement is not a specific sign

  18. MRI findings of sacroiliitis in ankylosing spondylitis: roles of MPGR and delayed post-contrast T1-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Eui Yong; Joo, Kyung Bin; Koo, Ja Hong; Moon, Won Jin; Hahm, Chang Kok; Kim, Tae Hwan; Kim, Seong Yoon [Hanyang Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-10-01

    For early diagnosis of sacroiliitis in spondyloarthropathy, the MRI findings of sacroiliitis, roles of MPGR(multiplanar Gradient Recalled Acquisition in Steady State), and delayed post-contrast T1-weighted images were evaluated. Twenty six patients with seronegative spondyloarthropathy(Probable clinical diagnosis of ankylosing spondylitis) were grouped as either less than radiographic grade 1(group A) or more than grade 2(group B). The MRI findings of both sacroiliac joints were evaluated in every patient, and predominant sites were determined. The two groups were then compared. In 17 patients, the number of enhancing panni seen on early and delayed post-contrast T1-weighted images was counted and compared between the two groups. Panni were found in all cases, and in both groups, predominant patterns of involvement were the lower and iliac aspects of the sacroiliac joints in both groups; in group A, the synovial joints and punctate pannus were predominantly involved, and in group B, the ligamentous joints as well as the synovial joints and linear pannus. In group B, More periarticular fat accumulation than periarticular osteitis was found. For the evaluation of changes in joint space, MPGR images were superior to spin echo images. For the delineation of enhancing pannus less than radiographic grade I, delayed post-contrast images were statistically superior to those which were early post-contrast. MRI can detect early sacroiliitic change according to the predominant sites of involvement, and deslyed post-contrast images play a role in the diagnosis of early sacroiliitis. MPGR imaging is good for the evaluation of joint space change.

  19. Contrast Enhanced MRI in the Diagnosis of HCC

    Directory of Open Access Journals (Sweden)

    Eric Niendorf

    2015-09-01

    Full Text Available Hepatocellular carcinoma (HCC is the 6th most common cancer worldwide. Imaging plays a critical role in HCC screening and diagnosis. Initial screening of patients at risk for HCC is performed with ultrasound. Confirmation of HCC can then be obtained by Computed Tomography (CT or Magnetic Resonance Imaging (MRI, due to the relatively high specificity of both techniques. This article will focus on reviewing MRI techniques for imaging HCC, felt by many to be the exam of choice for HCC diagnosis. MRI relies heavily upon the use of gadolinium-based contrast agents and while primarily extracellular gadolinium-based contrast agents are used, there is an emerging role of hepatobiliary contrast agents in HCC imaging. The use of other non-contrast enhanced MRI techniques for assessing HCC will also be discussed and these MRI strategies will be reviewed in the context of the pathophysiology of HCC to help understand the MR imaging appearance of HCC.

  20. Evaluation of sacroiliitis: contrast-enhanced MRI with subtraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Algin, Oktay; Gokalp, Gokhan; Baran, Bulent; Ocakoglu, Gokhan; Yazici, Zeynep [Uludag University, Medical Faculty, Department of Radiology, Gorukle, Bursa (Turkey)

    2009-10-15

    The purpose of the study was to investigate the diagnostic value of contrast-enhanced MRI using the subtraction technique in the detection of active sacroiliitis. Magnetic resonance imaging was performed in 8 asymptomatic volunteers and 50 patients with clinically suspected active sacroiliitis. On precontrast MR images, T1-weighted spin-echo images with and without fat saturation (T1WFS and T1W), STIR and 3D-FLASH images with fat saturation were obtained in the semicoronal plane using a 1.5 Tesla imager. Postcontrast MRI was performed using the same T1WFS sequence as before contrast injection for all volunteers and patients. Postcontrast images were subtracted from fat-suppressed precontrast images. Enhancement within the joint space and bone marrow was considered to demonstrate active sacroiliitis. In 50 patients (100 sacroiliac joints [SIJs]), 40 (76 SIJs) were considered to have active sacroiliitis based on MR images. Bone marrow edema was present in 33 patients (62 SIJs) on STIR images. Routine MRI allowed identification of contrast enhancement in SIJs on postcontrast T1WFS images in 31 patients (49 SIJs). Contrast enhancement was observed in 40 patients (76 SIJs) who were examined by MRI using the subtraction technique. Contrast enhancement was significantly more conspicuous on subtraction images than on non-subtracted postcontrast T1WFS images (Mann-Whitney U test, p<0.001). Contrast-enhanced MRI with subtraction technique may be useful for early detection of active sacroiliitis. (orig.)

  1. Usefulness of dynamic contrast-enhanced MRI in the evaluation of the viability of acute scaphoid fracture

    Energy Technology Data Exchange (ETDEWEB)

    Larribe, Maud [Hopital La Conception, Service d' imagerie medicale, Marseille (France); Hopital Sainte Marguerite, Service d' imagerie medicale, Marseille (France); Gay, Andre [Hopital La Conception, Service de chirurgie de la main, Marseille (France); Freire, Veronique [Centre hospitalier de l' Universite de Montreal, Department of Radiology, Notre-Dame Hospital, Montreal, QC (Canada); Bouvier, Corinne [Hopital La Timone, Service d' anatomopathologie, Marseille (France); Chagnaud, Christophe; Souteyrand, Philippe [Hopital La Conception, Service d' imagerie medicale, Marseille (France)

    2014-12-15

    To evaluate the usefulness of dynamic gadolinium-enhanced magnetic resonance imaging (MRI) for assessing the viability of the proximal pole of the scaphoid in patients with acute scaphoid fractures. Eighteen consecutive patients with acute scaphoid fracture who underwent dynamic gadolinium-enhanced MRI 7 days or less before surgery were prospectively included between August 2011 and December 2012. All patients underwent MR imaging with unenhanced images, enhanced images, and dynamic enhanced images. A radiologist first classified the MRI results as necrotic or viable based on T1- and T2-weighted images only, followed by a second blinded interpretation, this time including analysis of pre- and post-gadolinium administration images and a third blinded interpretation based on the time-intensity curve of the dynamic enhanced study. The standard of reference was the histologic assessment of a cylindrical specimen of the proximal pole obtained during surgery in all patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for unenhanced, enhanced, and dynamic gadolinium-enhanced MRI studies. The sensitivity, specificity, PPV, and NPV were 67, 67, 50, and 80 % for unenhanced images, 83, 100, 100, and 92 for enhanced images, and 83, 92, 83, and 92 for dynamic contrast-enhanced images. Our data are consistent with previously reported data supporting contrast-enhanced MRI for assessment of viability, and showing that dynamic imaging with time-intensity curve analysis does not provide additional predictive value over standard delayed enhanced imaging for acute scaphoid fracture. (orig.)

  2. Is enhanced MRI helpful in brainstem infarction?

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y. M.; Shin, G. H.; Choi, W. S. [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1994-12-15

    To determine the role of MR contrast enhancement in evaluating time course of brainstem infarction. MR imaging with IV administration of gadopentetate dimeglumine was retrospectively reviewed in 43 patients with clinically and radiologically documented brainstem infarctions. The pattern of infarction was classified into spotty and patchy. Presence of parenchymal enhancement in infarction was evaluated. By location, there were 34 pontine, 3 midbrain, 6 medullary infarctions. The age of the infarctions ranged from 1 day to 9 months, with 5 patients scanned within 3 days and 10 scanned within 2 weeks of clinical ictus. Abnormalities on T2-weighted images were encountered in every case, with spotty pattern in 14 cases and patchy pattern in 29 cases. Parenchymal contrast enhancement was seen in 9 cases(20%), primarily occurring between days 8 and 20. MR contrast enhancement in brainstem infarction was infrequent that it may not be useful in the estimation of the age of infarction.

  3. [Normal and abnormal meningeal enhancement: MRI features].

    Science.gov (United States)

    Dietemann, J L; Correia Bernardo, R; Bogorin, A; Abu Eid, M; Koob, M; Nogueira, Th; Vargas, M I; Fakhoury, W; Zöllner, G

    2005-11-01

    The authors describe normal imaging of the meninges and meningeal spaces and MR (magnetic resonance) imaging findings in tumoral and nontumoral diseases. Dural or/and pial enhancement may be related to tumoral, infectious or granulomatous diseases.

  4. MRI gadolinium enhancement precedes neuroradiological findings in acute necrotizing encephalopathy.

    Science.gov (United States)

    Yoshida, Takeshi; Tamura, Takuya; Nagai, Yuhki; Ueda, Hiroyuki; Awaya, Tomonari; Shibata, Minoru; Kato, Takeo; Heike, Toshio

    2013-11-01

    We report a 2-year-old Japanese boy with acute necrotizing encephalopathy (ANE) triggered by human herpes virus-6, who presented insightful magnetic resonance imaging (MRI) findings. He was admitted due to impaired consciousness and a convulsion, 2 days after the onset of an upper respiratory infection. At admission, cranial MRI showed marked gadolinium enhancement at the bilateral thalami, brainstem and periventricular white matter without abnormal findings in noncontrast MRI sequences. On the following day, noncontrast computed tomography demonstrated homogeneous low-density lesions in the bilateral thalami and severe diffuse brain edema. The patient progressively deteriorated and died on the 18th day of admission. The pathogenesis of ANE remains mostly unknown, but it has been suggested that hypercytokinemia may play a major role. Overproduced cytokines cause vascular endothelial damage and alter the permeability of the vessel wall in the multiple organs, including the brain. The MRI findings in our case demonstrate that blood-brain barrier permeability was altered prior to the appearance of typical neuroradiological findings. This suggests that alteration of blood-brain barrier permeability is the first step in the development of the brain lesions in ANE, and supports the proposed mechanism whereby hypercytokinemia causes necrotic brain lesions. This is the first report demonstrating MRI gadolinium enhancement antecedent to typical neuroradiological findings in ANE.

  5. TMJ disorders and pain: Assessment by contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Farina, Davide [Department of Radiology (School of Medicine), University of Brescia, Piazzale Spedali Civili 1, 25123 Brescia (Italy)], E-mail: nappaje@yahoo.it; Bodin, Christiane [Division of Gnathology (School of Dentistry), University of Brescia, Piazzale Spedali Civili 1, 25123 Brescia (Italy); Gandolfi, Silvia [Department of Radiology (School of Medicine), University of Brescia, Piazzale Spedali Civili 1, 25123 Brescia (Italy); De Gasperi, Werner [Division of Gnathology (School of Dentistry), University of Brescia, Piazzale Spedali Civili 1, 25123 Brescia (Italy); Borghesi, Andrea; Maroldi, Roberto [Department of Radiology (School of Medicine), University of Brescia, Piazzale Spedali Civili 1, 25123 Brescia (Italy)

    2009-04-15

    Though magnetic resonance (MRI) is a widely accepted standard for the assessment of patients with temporomandibular joint (TMJ) disorders, efforts to correlate symptoms to MRI findings have often given controversial results. Aim of this study was to investigate the correlation between TMJ pain and findings of contrast-enhanced MRI. Thirty-eight consecutive patients with TMJ dysfunction syndrome (study group) were examined with MRI. Protocol included T2 turbo spin-echo sequence, T1 spin-echo sequence, and T2 gradient-echo (acquired with closed jaw, at intermediate and maximal opening). Post-contrast phase was obtained through a fat sat 3D T1 gradient-echo sequence (VIBE). Post-contrast findings in the study group were matched with those obtained in a control group of 33 patients submitted to MRI of the paranasal sinuses. Statistically significant difference was found between condylar medullary bone enhancement in painful TMJ, in painless TMJ and control group. In addition the average thickness of joint soft tissue enhancement in painful TMJ was superior to painless TMJ (p < 0.0001) and to control group. On multivariate logistic regression analysis, the odds ratio that a painful TMJ showed disk displacement, osteoarthrosis, effusion and JST enhancement were 3.05, 3.18, 1.2 and 11.36, respectively. Though not histologically proven, TMJ enhancement could reflect the presence of inflammation in painful joints. Furthermore, the administration of contrast could be of help for the assessment of patients with orofacial pain, particularly when clinical exploration is insufficient to ascribe the pain to TMJ.

  6. Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced MRI versus Gadobenate Dimeglumine (Gd-BOPTA)-Enhanced MRI for Preoperatively Detecting Hepatocellular Carcinoma: an Initial Experience

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yu Lri; Kim, Seong Hyun; Kim, Seung Hoon; Choi, Dong Il; Lee, Won Jae; Kim, Hee Jung; Koo, Ji Hyun; Lim, Hyo Keun [Samsung Medical Center, Seoul (Korea, Republic of); Jeon, Yong Hwan [Kangwon National University Hospital, Chuncheon (Korea, Republic of); Lee, Jong Mee; Kim, Min Ju [Korea University College of Medicine, Korea University Guro Hospital, Seoul (Korea, Republic of)

    2010-08-15

    This study was designed to compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine-enhanced MRI for preoperatively detecting hepatocellular carcinoma (HCC). Eighteen consecutive patients (17 men and one woman, age range: 31-73 years) with 22 HCCs underwent examinations with gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI on a 3.0-Tesla unit. The diagnosis of HCC was established after surgical resection and pathological conformation. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC was assessed by performing an alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated. The average value of the area under the ROC curve (Az) for gadoxetic acid enhanced MRI (0.887) was not significantly different from the Az (0.899) for gadobenate dimeglumine-enhanced MRI (p > 0.05). The overall sensitivities of gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI were 80% and 83%, respectively, with no significant difference (p > 0.05). The differences of the positive predictive values for the two contrast agents for each observer were not statistically significant (p > 0.05). The diagnostic performance of gadoxetic acid-enhanced MRI and gadobenate dimeglumine-enhanced MRI for preoperatively detecting HCC is quite similar

  7. Human fMRI reveals that delayed action re-recruits visual perception.

    Science.gov (United States)

    Singhal, Anthony; Monaco, Simona; Kaufman, Liam D; Culham, Jody C

    2013-01-01

    Behavioral and neuropsychological research suggests that delayed actions rely on different neural substrates than immediate actions; however, the specific brain areas implicated in the two types of actions remain unknown. We used functional magnetic resonance imaging (fMRI) to measure human brain activation during delayed grasping and reaching. Specifically, we examined activation during visual stimulation and action execution separated by a 18-s delay interval in which subjects had to remember an intended action toward the remembered object. The long delay interval enabled us to unambiguously distinguish visual, memory-related, and action responses. Most strikingly, we observed reactivation of the lateral occipital complex (LOC), a ventral-stream area implicated in visual object recognition, and early visual cortex (EVC) at the time of action. Importantly this reactivation was observed even though participants remained in complete darkness with no visual stimulation at the time of the action. Moreover, within EVC, higher activation was observed for grasping than reaching during both vision and action execution. Areas in the dorsal visual stream were activated during action execution as expected and, for some, also during vision. Several areas, including the anterior intraparietal sulcus (aIPS), dorsal premotor cortex (PMd), primary motor cortex (M1) and the supplementary motor area (SMA), showed sustained activation during the delay phase. We propose that during delayed actions, dorsal-stream areas plan and maintain coarse action goals; however, at the time of execution, motor programming requires re-recruitment of detailed visual information about the object through reactivation of (1) ventral-stream areas involved in object perception and (2) early visual areas that contain richly detailed visual representations, particularly for grasping.

  8. Human fMRI reveals that delayed action re-recruits visual perception.

    Directory of Open Access Journals (Sweden)

    Anthony Singhal

    Full Text Available Behavioral and neuropsychological research suggests that delayed actions rely on different neural substrates than immediate actions; however, the specific brain areas implicated in the two types of actions remain unknown. We used functional magnetic resonance imaging (fMRI to measure human brain activation during delayed grasping and reaching. Specifically, we examined activation during visual stimulation and action execution separated by a 18-s delay interval in which subjects had to remember an intended action toward the remembered object. The long delay interval enabled us to unambiguously distinguish visual, memory-related, and action responses. Most strikingly, we observed reactivation of the lateral occipital complex (LOC, a ventral-stream area implicated in visual object recognition, and early visual cortex (EVC at the time of action. Importantly this reactivation was observed even though participants remained in complete darkness with no visual stimulation at the time of the action. Moreover, within EVC, higher activation was observed for grasping than reaching during both vision and action execution. Areas in the dorsal visual stream were activated during action execution as expected and, for some, also during vision. Several areas, including the anterior intraparietal sulcus (aIPS, dorsal premotor cortex (PMd, primary motor cortex (M1 and the supplementary motor area (SMA, showed sustained activation during the delay phase. We propose that during delayed actions, dorsal-stream areas plan and maintain coarse action goals; however, at the time of execution, motor programming requires re-recruitment of detailed visual information about the object through reactivation of (1 ventral-stream areas involved in object perception and (2 early visual areas that contain richly detailed visual representations, particularly for grasping.

  9. Contrast-enhanced MRI of murine myocardial infarction - part II.

    Science.gov (United States)

    Coolen, Bram F; Paulis, Leonie E M; Geelen, Tessa; Nicolay, Klaas; Strijkers, Gustav J

    2012-08-01

    Mouse models are increasingly used to study the pathophysiology of myocardial infarction in vivo. In this area, MRI has become the gold standard imaging modality, because it combines high spatial and temporal resolution functional imaging with a large variety of methods to generate soft tissue contrast. In addition, (target-specific) MRI contrast agents can be employed to visualize different processes in the cascade of events following myocardial infarction. Here, the MRI sequence has a decisive role in the detection sensitivity of a contrast agent. However, a straightforward translation of clinically available protocols for human cardiac imaging to mice is not feasible, because of the small size of the mouse heart and its extremely high heart rate. This has stimulated intense research in the development of cardiac MRI protocols specifically tuned to the mouse with regard to timing parameters, acquisition strategies, and ECG- and respiratory-triggering methods to find an optimal trade-off between sensitivity, scan time, and image quality. In this review, a detailed analysis is given of the pros and cons of different mouse cardiac MR imaging methodologies and their application in contrast-enhanced MRI of myocardial infarction. Copyright © 2012 John Wiley & Sons, Ltd.

  10. Detection of colorectal liver metastases: a prospective multicenter trial comparing unenhanced MRI, MnDPDP-enhanced MRI, and spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Bartolozzi, Carlo; Donati, Francescamaria; Cioni, Dania; Lencioni, Riccardo [Department of Radiology, University of Pisa, Via Roma 67, 56100, Pisa (Italy); Procacci, Carlo; Morana, Giovanni [Department of Radiology, University of Verona, Piazzale L.A. Scuro 1, 37134, Verona (Italy); Chiesa, Antonio; Grazioli, Luigi [Department of Radiology, University of Brescia, Piazzale Spedali Civili 1, 25023, Brescia (Italy); Cittadini, Giorgio; Cittadini, Giuseppe [Department of Radiology, University of Genova, Largo R. Benzi 10, 16132, Genova (Italy); Giovagnoni, Andrea [Department of Radiology, University of Ancona, Concam, Torrette, 60020, Ancona (Italy); Gandini, Giovanni; Maass, Jochen [Department of Radiology, University of Torino, Genova 3, 10110, Torino (Italy)

    2004-01-01

    The aim of this study was to compare unenhanced MRI, MnDPDP-enhanced MRI, and spiral CT in the detection of hepatic colorectal metastases. Forty-four patients with hepatic colorectal metastases were examined with unenhanced and MnDPDP-enhanced MRI and with unenhanced and contrast-enhanced spiral CT. The MR examination protocol included baseline T1-weighted spin-echo (SE), T1-weighted gradient-recalled-echo (GRE), and T2-weighted fast-SE sequences; and T1-weighted SE and T1-weighted GRE sequences obtained 30-60 min after administration of 0.5 {mu}mol/kg (0.5 ml/kg) mangafodipir trisodium (MnDPDP). Images were interpreted by three blinded readers. Findings at CT and MRI were compared with those at intraoperative US, which were used as term of reference. Intraoperative US detected 128 metastases. In a lesion-by-lesion analysis, the overall detection rate was 71% (91 of 128) for spiral CT, 72% (92 of 128) for unenhanced MRI, and 90% (115 of 128) for MnDPDP-enhanced MRI. MnDPDP-enhanced MRI was more sensitive than either unenhanced MRI (p<0.0001) or spiral CT (p=0.0007). In a patient-by-patient analysis, agreement with gold standard was higher for MnDPDP-enhanced MRI (33 of 44 cases) than for spiral CT (22 of 44 cases, p=0.0023) and unenhanced MRI (21 of 44 cases, p=0.0013). MnDPDP-enhanced MRI is superior to unenhanced MRI and spiral CT in the detection of hepatic colorectal metastases. (orig.)

  11. Dynamic oxygen-enhanced MRI of cerebrospinal fluid.

    Directory of Open Access Journals (Sweden)

    Taha M Mehemed

    Full Text Available Oxygen causes an increase in the longitudinal relaxation rate of tissues through its T1-shortening effect owing to its paramagnetic properties. Due to such effects, MRI has been used to study oxygen-related signal intensity changes in various body parts including cerebrospinal fluid (CSF space. Oxygen enhancement of CSF has been mainly studied using MRI sequences with relatively longer time resolution such as FLAIR, and T1 value calculation. In this study, fifteen healthy volunteers were scanned using fast advanced spin echo MRI sequence with and without inversion recovery pulse in order to dynamically track oxygen enhancement of CSF. We also focused on the differences of oxygen enhancement at sulcal and ventricular CSF. Our results revealed that CSF signal after administration of oxygen shows rapid signal increase in both sulcal CSF and ventricular CSF on both sequences, with statistically significant predominant increase in sulcal CSF compared with ventricular CSF. CSF is traditionally thought to mainly form from the choroid plexus in the ventricles and is absorbed at the arachnoid villi, however, it is also believed that cerebral arterioles contribute to the production and absorption of CSF, and controversy remains in terms of the precise mechanism. Our results demonstrated rapid oxygen enhancement in sulcal CSF, which may suggest inhaled oxygen may diffuse into sulcal CSF space rapidly probably due to the abundance of pial arterioles on the brain sulci.

  12. Multiple renal aspergillus abscesses in an AIDS patient: contrast-enhanced helical CT and MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Heussel, C.P.; Kauczor, H.U.; Thelen, M. [Dept. of Radiology, Johannes Gutenberg Univ., Mainz (Germany); Heussel, G. [Dept. of Internal Medicine, Johannes Gutenberg Univ., Mainz (Germany); Jahn, B. [Inst. of Microbiology, Johannes Gutenberg Univ., Mainz (Germany)

    1999-05-01

    Renal insufficiency or allergic reactions for X-ray contrast agents are frequent limitations in immunocompromised hosts such as neutropenic or AIDS patients. Due to a better tolerance of contrast agents in MRI, this technique is well suited for investigation of parenchymal organs. We demonstrate an allergic AIDS patient who presented with fever and flank pain. At sonography, anechoic renal lesions were supposed to be non-complicated cysts; however, on T2-weighted MRI, the center was of high signal. Dynamic contrast-enhanced MRI of the kidneys demonstrated an enhancing rim with ill-defined margins. The lesions were supposed to be multiple bilateral abscesses. Due to the multiple dynamic contrast series, a delayed enhancement of renal parenchyma was detectable adjacent to the lesion. This was suggested as accompanying local pyelonephritis and an infectious etiology became more reliable. Aspergillus fumigatus was identified by CT-guided biopsy as the underlying microorganism. The MR appearance of this manifestation has not been described previously. (orig.) With 5 figs., 15 refs.

  13. Medial tibial pain: a dynamic contrast-enhanced MRI study.

    Science.gov (United States)

    Mattila, K T; Komu, M E; Dahlström, S; Koskinen, S K; Heikkilä, J

    1999-09-01

    The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrast enhanced imaging to show periosteal edema and abnormal contrast enhancement within a compartment.

  14. Whole-body MRI, dynamic contrast-enhanced MRI, and diffusion-weighted imaging for the staging of multiple myeloma

    Energy Technology Data Exchange (ETDEWEB)

    Dutoit, Julie C.; Verstraete, Koenraad L. [Ghent University Hospital, Department of Radiology, Ghent (Belgium)

    2017-06-15

    Magnetic resonance imaging (MRI) is the most sensitive imaging technique for the detection of bone marrow infiltration, and has therefore recently been included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. Nevertheless, conventional MRI only provides anatomical information and is therefore only of limited use in the response assessment of patients with multiple myeloma. The additional information from functional MRI techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, can improve the detection rate of bone marrow infiltration and the assessment of response. This can further enhance the sensitivity and specificity of MRI in the staging of multiple myeloma patients. This article provides an overview of the technical aspects of conventional and functional MRI techniques with practical recommendations. It reviews the diagnostic performance, prognostic value, and role in therapy assessment in multiple myeloma and its precursor stages. (orig.)

  15. Enhanced MRI in patients with facial palsy; Study of time-related enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Masahiro; Kato, Tsutomu; Ushiro, Koichi; Kitajiri, Masanori; Yamashita, Toshio; Kumazawa, Tadami; Tanaka, Yoshimasa (Kansai Medical School, Moriguchi, Osaka (Japan))

    1991-03-01

    We performed Gd-DTPA-enhanced magnetic resonance imaging (MRI) examinations at several stages in 40 patients with peripheral facial nerve palsy (Bell's palsy and Ramsay-Hunt syndrome). In 38 of the 40 patients, one and more enhanced region could be seen in certain portion of the facial nerve in the temporal bone on the affected side, whereas no enhanced regions were seen on the intact side. Correlations between the timing of the MRI examination and the location of the enhanced regions were analysed. In all 6 patients examined by MRI within 5 days after the onset of facial nerve palsy, enhanced regions were present in the meatal portion. In 3 of the 8 patients (38%) examined by MRI 6 to 10 days after the onset of facial palsy, enhanced areas were seen in both the meatal and labyrinthine portions. In 8 of the 9 patients (89%) tested 11 to 20 days after the onset of palsy, the vertical portion was enhanced. In the 12 patients examined by MRI 21 to 40 days after the onset of facial nerve palsy, the meatal portion was not enhanced while the labyrinthine portion, the horizontal portion and the vertical portion were enhanced in 5 (42%), 8 (67%) and 11 (92%), respectively. Enhancement in the vertical portion was observed in all 5 patients examined more than 41 days after the onset of facial palsy. These results suggest that the central portion of the facial nerve in the temporal bone tends to be enhanced in the early stage of facial nerve palsy, while the peripheral portion is enhanced in the late stage. These changes of Gd-DTPA enhanced regions in the facial nerve may suggest dromic degeneration of the facial nerve in peripheral facial nerve palsy. (author).

  16. Motion correction of dynamic contrast enhanced MRI of the liver

    Science.gov (United States)

    Jansen, Mariëlle J. A.; Veldhuis, Wouter B.; van Leeuwen, Maarten S.; Pluim, Josien P. W.

    2017-02-01

    Motion correction of dynamic contrast enhanced magnetic resonance images (DCE-MRI) is a challenging task, due to changes in image appearance. In this study a groupwise registration, using a principle component analysis (PCA) based metric, is evaluated for clinical DCE MRI of the liver. The groupwise registration transforms the images to a common space, rather than to a reference volume as conventional pairwise methods do, and computes the similarity metric on all volumes simultaneously. This groupwise registration method is compared to a pairwise approach using a mutual information metric. Clinical DCE MRI of the abdomen of eight patients were included. Per patient one lesion in the liver was manually segmented in all temporal images (N=16). The registered images were compared for accuracy, spatial and temporal smoothness after transformation, and lesion volume change. Compared to a pairwise method or no registration, groupwise registration provided better alignment. In our recently started clinical study groupwise registered clinical DCE MRI of the abdomen of nine patients were scored by three radiologists. Groupwise registration increased the assessed quality of alignment. The gain in reading time for the radiologist was estimated to vary from no difference to almost a minute. A slight increase in reader confidence was also observed. Registration had no added value for images with little motion. In conclusion, the groupwise registration of DCE MR images results in better alignment than achieved by pairwise registration, which is beneficial for clinical assessment.

  17. Diagnositc value of 3D-gradient echo dynamic contrast enhanced MRI in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ik; Chung, Soo Young; Park, Hai Jung; Lee, Yul; Chung, Bong Wha; Shim, Jeong Won [Hallym Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-10-01

    To assess the usefulness of 3D-gradient echo dynamic contrast enhanced MRI (3D-DMRI) in the diagnosis of breast cancer and to determine the most useful parameter for this diagnosis. Using a 1.0T MR unit, (Magnetom, Siemens, Erlaugen, Germany), 3D-DMRI (TR/TE=3D30/12) with Gd-DTPA was performed in 38 cases of breast cancer, 22 of fibroadenoma, and in three normal volunteers. We retrospectively evaluated the findings according to the speed on dynamic study and maximal amount of contrast enhancement during the delayed phase;we calculated the contrast index and morphology of the cancers and compared diagnostic accuracy among these three diagnostic parameters. On conventional spin-echo T1-and T2-weighted images, there was no significant difference of signal intensity between benign fibroadenoma and breast carcinoma. Rapid contrast enhancement (within one minute) was noted in 35 breast cancer lesions (92.1%), but relatively low and slow contrast enhancement (after five minutes) was noted in three such lesions (7.9%). Gradual contrast enhancement was noted in 21 lesions of fibroadenoma(95.5%), but a moderate degree of rapid contrast enhancement (from three to five minutes) was noted in the other case (7.9%). of On the delayed enhanced phase of 3D-DMRI, the maximal amount of contrast enhancement showed no significant difference between fibroadenoma and cancer. On 3D-DMRI, an irregular, spiculated border, with high contrast enhancement was noted in all cases of breast cancer, in particular, irregular thick peripheral contrast enhancement with central necrosis was noted 11cases(28.9%). For the diagnosis of breast cancer, 3D-DMRI is a useful technique. Among the diagnostic criteria of speed, maximal amount of contrast enhancement and morphology, morphologic change after contrast enhancement study was the most useful diagnostic parameter.=20.

  18. Emerging concepts for myocardial late gadolinium enhancement MRI.

    Science.gov (United States)

    Doltra, Adelina; Amundsen, Brage Hoyem; Gebker, Rolf; Fleck, Eckart; Kelle, Sebastian

    2013-08-01

    Late gadolinium enhancement is a useful tool for scar detection, based on differences in the volume of distribution of gadolinium, an extracellular agent. The presence of fibrosis in the myocardium amenable to be detected with late gadolinium enhancement MRI is found not only in ischemic cardiomyopathy, in which it offers information regarding viability and prognosis, but also in a wide variety of non-ischemic cardiomyopathies. In the following review we will discuss the methodological aspects of gadolinium-based imaging, as well as its applications and anticipated future developments.

  19. The cerebral intravascular enhancement sign is not specific: a contrast-enhanced MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Bakshi, R.; Kinkel, W.R.; Bates, V.E.; Mechtler, L.L.; Kinkel, P.R. [Lucy Dent Imaging Center, University at Buffalo, NY (United States)

    1999-02-01

    The intravascular enhancement (IVE) sign, also known as the ``arterial enhancement sign``, is an abnormal finding in the brain on contrast-enhanced MRI studies. IVE has been described in arterial cerebrovascular disorders, most commonly in acute or subacute arterial ischemic infarcts. However, the specificity of this sign has not been established. We describe four patients with disorders other than arterial strokes in whom gadolinium-enhanced high-field (1.5 T) MRI suggested IVE. The conditions were herpes simplex viral encephalitis, idiopathic cerebellitis, pneumococcal meningitis, and superior sagittal sinus thrombosis with venous infarction. IVE in these cases may be due to multiple factors, including arterial, venous, perivascular, and leptomeningeal or sulcal contrast medium accumulation. Our observations suggest that arterial ischemia, previously described as the cardinal cause of IVE, probably does not explain all instances, and urge caution in interpreting this sign as a specific MRI manifestation of acute arterial infarction or ischemia. (orig.) With 4 figs., 1 tab., 44 refs.

  20. Gadolinium-enhanced MRI in a patient with AIDS and the Ramsay-Hunt syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. (Neuroradiology Section, Univ. of Texas Health Science Center, San Antonio, TX (United States)); Xiong, L. (Neuroradiology Section, Univ. of Texas Health Science Center, San Antonio, TX (United States)); Jinkins, J.R. (Neuroradiology Section, Univ. of Texas Health Science Center, San Antonio, TX (United States))

    1993-04-01

    Conrast-enhanced MRI is very sensitive to disease in the internal auditory meatus, but lacks specificity. This report illustrates the MRI findings in the Ramsay-Hunt syndrome caused by herpes zoster infection in a patient with AIDS. (orig.)

  1. Dynamic contrast-enhanced MRI for monitoring response to neoadjuvant chemotherapy in breast cancer

    OpenAIRE

    Loo, C E

    2016-01-01

    The general aim of this thesis is to investigate the role of dynamic contrast-enhanced MRI in monitoring response of breast cancer during neoadjuvant chemotherapy. The role of MRI with respect to achieving personalized breast cancer treatment by improving response monitoring is examined. Our findings demonstrate the potential clinical relevance of contrast-enhanced MRI for monitoring response of breast cancer during and after neoadjuvant chemotherapy. We defined MRI criteria ( reduction < 25%...

  2. Patients with liver FNH and HCC patients with negative AFP: plain and dynamic enhanced MRI and CT findings

    Directory of Open Access Journals (Sweden)

    LI Mingtong

    2015-05-01

    Full Text Available ObjectiveTo investigate plain and dynamic enhanced magnetic resonance imaging (MRI and computed tomography (CT findings in patients with focal nodular hyperplasia (FNH of the liver and hepatocellular carcinoma (HCC patients with negative alpha-fetoprotein (AFP. MethodsA statistical analysis was performed on the clinical data of 124 cases of liver tumor admitted to Beijing Miyun County Hospital from April 2012 to April 2014. ResultsFifty-five of the 74 patients with FNH underwent CT examination, among whom 38 patients received three-phase dynamic enhanced scan and 16 received only plain scan; 62 cases had plain and enhanced MRI with the application of contrast agent Gd-BOPTA in 42 patients. Among the 50 HCC patients with negative AFP, CT examination was performed in 40 and 10 only had plain scan; 46 patients received plain and enhanced MRI with the use of contrast agent Gd-BOPTA in 30. Delayed scan after 1-2 h demonstrated low signal in 30 lesions of the 30 cases. ConclusionFor patients with liver FNH and AFP-negative HCC patients, their plain and dynamic enhanced MRI and CT scan have respective characteristics. A combination of multiple examination methods can significantly improve diagnostic yield of the two diseases.

  3. Enhancement patterns and pseudo-washout of hepatic haemangiomas on gadoxetate disodium-enhanced liver MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bohyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Ajou University School of Medicine, Department of Radiology, Suwon (Korea, Republic of); Byun, Jae Ho; Kim, Hyoung Jung; Won, Hyung Jin; Kim, So Yeon; Shin, Yong Moon; Kim, Pyo Nyun [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of)

    2016-01-15

    To compare the enhancement patterns and prevalence of pseudo-washout between rapidly and slowly enhancing hepatic haemangiomas on gadoxetate disodium-enhanced MRI in patients with chronic liver disease (CLD) and healthy liver (HL). On gadoxetate disodium-enhanced MRI, the extent of intralesional arterial enhancement >50 % and ≤50 % of lesions was defined as rapid and slow enhancement, respectively. The enhancement patterns and presence of pseudo-washout during the portal venous phase (PVP) and transitional phase (TP) of 74 hepatic haemangiomas were retrospectively evaluated in the CLD and HL groups. Sequential changes of signal-to-noise ratio (SNR) were measured in unenhanced phase, PVP and TP. Irrespective of hepatic health status, pseudo-washout in TP was significantly more common in the rapidly enhancing haemangiomas (p ≤ 0.026). In both groups, rapidly enhancing haemangiomas showed complete or progressive incomplete enhancement in PVP, which either lasted or transformed to pseudo-washout in TP, whereas slowly enhancing haemangiomas showed progressive incomplete enhancement in PVP and TP. SNR of hepatic parenchyma continued to rise until TP, whereas that of portal vein and haemangioma falls in TP. Regardless of CLD, pseudo-washout in TP was more common in rapidly than in slowly enhancing haemangiomas, with enhancement patterns differing in the two subgroups. (orig.)

  4. A utility of AMI-25 enhanced MRI for HCC

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Hiromichi; Saito, Kazuhiro; Saguchi, Tohru (Tokyo Medical Coll. (Japan)) (and others)

    1993-05-01

    After injection of superparamagnetic iron oxide (AMI-25), the detection number of hepatocellular carcinoma (HCC) increased over 2 times. But in some cases, contrast to noise ratio did not change. The most excellent pulse sequence for detection of HCC was T2-weighted images, but field echo image had a better capability due to a strong T2 relaxation. Two cases of adenomatous hyperplasia decreased their signal intensities after injection of AMI-25, but well differentiated HCC also did. In two HCCs with peripheral hyperintensity (PHI), one of PHI disappeared on the AMI-25 enhanced MRI, but another did not. (author).

  5. Diffuse Infantile Hepatic Hemangioendothelioma With Early Central Enhancement in an Adult: A Case Report of CT and MRI Findings.

    Science.gov (United States)

    Dong, Aisheng; Dong, Hui; Zuo, Changjing; He, Tianlin

    2015-12-01

    Infantile hepatic hemangioendothelioma (IHH) is the most common vascular tumor of the liver in infancy. Adult with IHH is extremely rare. We presented a diffuse IHH in an adult patient with computed tomography (CT) and magnetic resonance image (MRI) findings.A 39-year-old man was admitted to our hospital because of a 2-year history of abnormal liver function tests and a 7-day history of jaundice. Physical examination revealed enlarged liver. Unenhanced abdominal CT showed enlargement of the liver with diffuse hypodensity. Enhanced CT on the arterial phase revealed multiple centrally enhanced lesions diffusely involved the enlarged liver. The enhanced areas of the lesions became larger on the portal phase and all the lesions became homogeneous enhanced on the delayed phase. These lesions showed heterogeneously hyperintense on T2-weighted image, hypointense on T1-weighted image, and early centrally enhanced on dynamic gadolinium-enhanced MRI, with complete tumor enhancement after 180 s. The patient underwent orthotopic liver transplantation. IHH type 2 was confirmed by pathology. The patient died of tumor recurrence in the liver 4 months after transplantation.Unlike the previously described imaging appearances of IHH, this case showed diffuse nodules with early central enhancement on CT and MRI. Considering the importance of the ability to differentiate IHH from other hepatic tumors, radiologists should be aware of these imaging appearances to establish knowledge of the entire spectrum of IHH.

  6. A simulation tool for dynamic contrast enhanced MRI.

    Directory of Open Access Journals (Sweden)

    Nicolas Adrien Pannetier

    Full Text Available The quantification of bolus-tracking MRI techniques remains challenging. The acquisition usually relies on one contrast and the analysis on a simplified model of the various phenomena that arise within a voxel, leading to inaccurate perfusion estimates. To evaluate how simplifications in the interstitial model impact perfusion estimates, we propose a numerical tool to simulate the MR signal provided by a dynamic contrast enhanced (DCE MRI experiment. Our model encompasses the intrinsic R1 and R2 relaxations, the magnetic field perturbations induced by susceptibility interfaces (vessels and cells, the diffusion of the water protons, the blood flow, the permeability of the vessel wall to the the contrast agent (CA and the constrained diffusion of the CA within the voxel. The blood compartment is modeled as a uniform compartment. The different blocks of the simulation are validated and compared to classical models. The impact of the CA diffusivity on the permeability and blood volume estimates is evaluated. Simulations demonstrate that the CA diffusivity slightly impacts the permeability estimates (< 5% for classical blood flow and CA diffusion. The effect of long echo times is investigated. Simulations show that DCE-MRI performed with an echo time TE = 5 ms may already lead to significant underestimation of the blood volume (up to 30% lower for brain tumor permeability values. The potential and the versatility of the proposed implementation are evaluated by running the simulation with realistic vascular geometry obtained from two photons microscopy and with impermeable cells in the extravascular environment. In conclusion, the proposed simulation tool describes DCE-MRI experiments and may be used to evaluate and optimize acquisition and processing strategies.

  7. Gadofluorine M-enhanced MRI shows involvement of circumventricular organs in neuroinflammation

    Directory of Open Access Journals (Sweden)

    Glumm Robert

    2010-10-01

    Full Text Available Abstract Background Circumventricular organs (CVO are cerebral areas with incomplete endothelial blood-brain barrier (BBB and therefore regarded as "gates to the brain". During inflammation, they may exert an active role in determining immune cell recruitment into the brain. Methods In a longitudinal study we investigated in vivo alterations of CVO during neuroinflammation, applying Gadofluorine M- (Gf enhanced magnetic resonance imaging (MRI in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. SJL/J mice were monitored by Gadopentate dimeglumine- (Gd-DTPA and Gf-enhanced MRI after adoptive transfer of proteolipid-protein-specific T cells. Mean Gf intensity ratios were calculated individually for different CVO and correlated to the clinical disease course. Subsequently, the tissue distribution of fluorescence-labeled Gf as well as the extent of cellular inflammation was assessed in corresponding histological slices. Results We could show that the Gf signal intensity of the choroid plexus, the subfornicular organ and the area postrema increased significantly during experimental autoimmune encephalomyelitis, correlating with (1 disease severity and (2 the delay of disease onset after immunization. For the choroid plexus, the extent of Gf enhancement served as a diagnostic criterion to distinguish between diseased and healthy control mice with a sensitivity of 89% and a specificity of 80%. Furthermore, Gf improved the detection of lesions, being particularly sensitive to optic neuritis. In correlated histological slices, Gf initially accumulated in the extracellular matrix surrounding inflammatory foci and was subsequently incorporated by macrophages/microglia. Conclusion Gf-enhanced MRI provides a novel highly sensitive technique to study cerebral BBB alterations. We demonstrate for the first time in vivo the involvement of CVO during the development of neuroinflammation.

  8. Combined gadoxetic acid and gadofosveset enhanced liver MRI for detection and characterization of liver metastases

    Energy Technology Data Exchange (ETDEWEB)

    Bannas, Peter [University of Wisconsin-Madison, Department of Radiology, Madison, WI (United States); University Medical Center Hamburg-Eppendorf, Department of Radiology, University Hospital, Hamburg (Germany); Bookwalter, Candice A.; Ziemlewicz, Tim; Munoz del Rio, Alejandro; Potretzke, Theodora A. [University of Wisconsin-Madison, Department of Radiology, Madison, WI (United States); Motosugi, Utaroh [University of Wisconsin-Madison, Department of Radiology, Madison, WI (United States); University of Yamanashi, Department of Radiology, Yamanashi (Japan); Nagle, Scott K. [University of Wisconsin-Madison, Department of Radiology, Madison, WI (United States); University of Wisconsin-Madison, Department of Medical Physics, Madison, WI (United States); University of Wisconsin-Madison, Department of Pediatrics, Madison, WI (United States); Reeder, Scott B. [University of Wisconsin-Madison, Department of Radiology, Madison, WI (United States); University of Wisconsin-Madison, Department of Medical Physics, Madison, WI (United States); University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, WI (United States); University of Wisconsin-Madison, Department of Medicine, Madison, WI (United States); University of Wisconsin-Madison, Department of Emergency Medicine, Madison, WI (United States)

    2017-01-15

    To compare gadoxetic acid alone and combined gadoxetic acid/gadofosveset trisodium-enhanced liver MRI for detection of metastases and differentiation of metastases from haemangiomas. Ninety-one patients underwent gadoxetic acid-enhanced liver MRI before and after additional injection of gadofosveset. First, two readers retrospectively identified metastases on gadoxetic acid alone enhanced delayed hepatobiliary phase T1-weighted images together with all other MR images (dynamic images, T2-weighted images, diffusion-weighted images). Second, readers assessed additional T1-weighted images obtained after administration of gadofosveset trisodium. For both interpretations, readers rated lesion conspicuity and confidence in differentiating metastases from haemangiomas. Results were compared using alternative free-response receiver-operating characteristic (AFROC) and conventional ROC methods. Histology and follow-up served as reference standard. There were 145 metastases and 16 haemangiomas. Both readers detected more metastases using combined gadoxetic acid/gadofosveset (reader 1 = 130; reader 2 = 124) compared to gadoxetic acid alone (reader 1 = 104; reader 2 = 103). Sensitivity of combined gadoxetic acid/gadofosveset (reader 1 = 90 %; reader 2 = 86 %) was higher than that of gadoxetic acid alone (reader 1 = 72 %; reader 2 = 71 %, both P < 0.01). AFROC-AUC was higher for the combined technique (0.92 vs. 0.86, P < 0.001). Sensitivity for correct differentiation of metastases from haemangiomas was higher for the combined technique (reader 1 = 98 %; reader 2 = 99 % vs. reader 1 = 86 %; reader 2 = 91 %, both P < 0.01). ROC-AUC was significantly higher for the combined technique (reader 1 = 1.00; reader 2 = 1.00 vs. reader 1 = 0.87; reader 2 = 0.92, both P < 0.01). Combined gadoxetic acid/gadofosveset-enhanced MRI improves detection and characterization of liver metastases compared to gadoxetic acid alone. (orig.)

  9. Delayed Gadolinium-Enhanced Magnetic Resonance Imaging (dGEMRIC) of Hip Joint Cartilage: Better Cartilage Delineation after Intra-Articular than Intravenous Gadolinium Injection

    DEFF Research Database (Denmark)

    Boesen, M.; Jensen, K.E.; Quistgaard, E.;

    2006-01-01

    PURPOSE: To investigate and compare delayed gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in the hip joint using intravenous (i.v.) or ultrasound-guided intra-articular (i.a.) Gd-DTPA injection. MATERIAL AND METHODS: In 10 patients (50% males, mean age 58...

  10. Noise-enhanced phase synchronization in time-delayed systems.

    Science.gov (United States)

    Senthilkumar, D V; Shrii, M Manju; Kurths, J

    2012-02-01

    We investigate the phenomenon of noise-enhanced phase synchronization (PS) in coupled time-delay systems, which usually exhibit non-phase-coherent attractors with complex topological properties. As a delay system is essentially an infinite dimensional in nature with multiple characteristic time scales, it is interesting and crucial to understand the interplay of noise and the time scales in achieving PS. In unidirectionally coupled systems, the response system adjust all its time scales to that of the drive, whereas both subsystems adjust their rhythms to a single (main time scale of the uncoupled system) time scale in bidirectionally coupled systems. We find similar effects for both a common and an independent additive Gaussian noise.

  11. Delayed effects of cortisol enhance fear memory of trace conditioning.

    Science.gov (United States)

    Cornelisse, Sandra; van Ast, Vanessa A; Joëls, Marian; Kindt, Merel

    2014-02-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distinction is of special interest because the neural substrates underlying these types of conditioning may be differently affected by time-dependent cortisol effects. Delay conditioning is predominantly amygdala-dependent, while trace conditioning additionally requires the hippocampus. Here, we manipulated the timing of cortisol action during acquisition of delay and trace fear conditioning, by randomly assigning 63 men to one of three possible groups: (1) receiving 10mg hydrocortisone 240 min (slow cort) or (2) 60 min (rapid cort) before delay and trace acquisition, or (3) placebo at both times, in a double-blind design. The next day, we tested memory for trace and delay conditioning. Fear potentiated startle responses, skin conductance responses and unconditioned stimulus expectancy scores were measured throughout the experiment. The fear potentiated startle data show that cortisol intake 240 min before actual fear acquisition (slow cort) uniquely strengthened subsequent trace conditioned memory. No effects of cortisol delivery 60 min prior to fear acquisition were found on any measure of fear memory. Our findings emphasize that slow, presumably genomic, but not more rapid effects of corticosteroids enhance hippocampal-dependent fear memories. On a broader level, our findings underline that basic experimental research and clinically relevant pharmacological treatments employing corticosteroids should acknowledge the timing of corticosteroid administration relative to the learning phase, or therapeutic intervention.

  12. Dynamic contrast enhancement of experimental glioma an intra-individual comparative study to assess the optimal time delay.

    Science.gov (United States)

    Engelhorn, Tobias; Schwarz, Marc A; Eyupoglu, Ilker Y; Kloska, Stephan P; Struffert, Tobias; Doerfler, Arnd

    2010-02-01

    The aim of this study was to compare tumor signal and contrast media uptake characteristics on contrast-enhanced T1-weighted sequences at 3 Tesla over 30 minutes after double-dose administration of different contrast agents in an animal model of brain glioma. Nine rats underwent magnetic resonance imaging (MRI) after stereotactic F98 glioma cell implantation before and repetitively for 30 minutes after injection of gadobutrol, gadopentetate, and gadobenate, respectively. Signal-to-noise ratio (SNR) and tumor contrast-to-noise ratio (CNR) were evaluated and MRI-derived tumor volumes were compared to histology. Postcontrast tumor SNR and CNR peaked at 4 minutes after contrast application. While contrast-enhancement within the tumor was fading, tumor volume increased by continuous contrast-uptake of peripheral parts between 4 minutes (137 + or - 29 mm(3), 126 + or - 16 mm(3), 141 + or - 24 mm(3)) and 20 minutes (182 + or - 35 mm(3), 164 + or - 32 mm(3), 191 + or - 25 mm(3)), respectively. At 8 and 12 minutes, 84% and 91% of the tumor volume were definable, respectively. Optimal correlation between MRI-derived tumor volume and histology is achieved by imaging up to 20 minutes after contrast application. At 4 minutes (this delay is mostly used in clinical routine), only 75% of the enhancing tumor volume is assessable. A delay of 8 minutes already reveals 84% of the tumor and seems to be a practical clinical compromise. Copyright 2010 AUR. Published by Elsevier Inc. All rights reserved.

  13. Pathological mechanism for delayed hyperenhancement of chronic scarred myocardium in contrast agent enhanced magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Jian Wang

    Full Text Available OBJECTIVES: To evaluate possible mechanism for delayed hyperenhancement of scarred myocardium by investigating the relationship of contrast agent (CA first pass and delayed enhancement patterns with histopathological changes. MATERIALS AND METHODS: Eighteen pigs underwent 4 weeks ligation of 1 or 2 diagonal coronary arteries to induce chronic infarction. The hearts were then removed and perfused in a Langendorff apparatus. The hearts firstly experienced phosphorus 31 MR spectroscopy. The hearts in group I (n = 9 and II (n = 9 then received the bolus injection of Gadolinium diethylenetriamine pentaacetic acid (0.05 mmol/kg and gadolinium-based macromolecular agent (P792, 15 µmol/kg, respectively. First pass T2* MRI was acquired using a gradient echo sequence. Delayed enhanced T1 MRI was acquired with an inversion recovery sequence. Masson's trichrome and anti- von Willebrand Factor (vWF staining were performed for infarct characterization. RESULTS: Wash-in of both kinds of CA caused the sharp and dramatic T2* signal decrease of scarred myocardium similar to that of normal myocardium. Myocardial blood flow and microvessel density were significantly recovered in 4-week-old scar tissue. Steady state distribution volume (ΔR1 relaxation rate of Gd-DTPA was markedly higher in scarred myocardium than in normal myocardium, whereas ΔR1 relaxation rate of P792 did not differ significantly between scarred and normal myocardium. The ratio of extracellular volume to the total water volume was significantly greater in scarred myocardium than in normal myocardium. Scarred myocardium contained massive residual capillaries and dilated vessels. Histological stains indicated the extensively discrete matrix deposition and lack of cellular structure in scarred myocardium. CONCLUSIONS: Collateral circulation formation and residual vessel effectively delivered CA into scarred myocardium. However, residual vessel without abnormal hyperpermeability allowed Gd

  14. Gd-EOB-DTPA enhanced MRI of the liver: Correlation of relative hepatic enhancement, relative renal enhancement, and liver to kidneys enhancement ratio with serum hepatic enzyme levels and eGFR

    Energy Technology Data Exchange (ETDEWEB)

    Talakic, Emina; Steiner, Jürgen; Kalmar, Peter; Lutfi, Andre [Division of General Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Quehenberger, Franz [Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, 8036 Graz (Austria); Reiter, Ursula; Fuchsjäger, Michael [Division of General Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Schöllnast, Helmut, E-mail: helmut.schoellnast@medunigraz.at [Division of General Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 9, 8036 Graz (Austria)

    2014-04-15

    Objectives: To assess the correlation of relative hepatic enhancement (RHE), relative renal enhancement (RRE) and liver to kidneys enhancement ratio (LKR) with serum hepatic enzyme levels and eGFR in Gd-EOB-DTPA enhanced MRI of the liver and to assess threshold levels for predicting enhancement of the liver parenchyma. Methods: Data of 75 patients who underwent Gd-EOB-DTPA enhanced MRI of the liver were collected. Images were obtained before contrast injection, during the early arterial phase, late arterial phase, venous phase, delayed phase, and hepatobiliary phase which was 20 min after Gd-EOB-DTPA administration. Signal intensity of the liver and the kidneys in all phases was defined using region-of-interest measurements for relative enhancement calculation. Serum hepatic enzyme levels and eGFR were available in all patients. Spearman correlation test was used to test the correlation of RHE, RRE and LKR with serum hepatic enzyme levels and eGFR. Results: In the hepatobiliary phase all serum hepatic enzymes were significantly correlated with RHE; total bilirubin (TBIL) and cholin esterase (CHE) showed strongest correlations. TBIL and CHE were significantly correlated with RRE in the arterial phases. TBIL and CHE were significantly correlated with LKR in the arterial phase and hepatobiliary phase. eGFR showed no correlation. Conclusions: In Gd-EOB-DTPA enhanced MRI, TBIL and CHE levels may predict RHE, RRE and LKR.

  15. Comparison of infarct size changes with delayed contrast-enhanced magnetic resonance imaging and electrocardiogram QRS scoring during the 6 months after acutely reperfused myocardial infarction

    DEFF Research Database (Denmark)

    Bang, L.E.; Ripa, R.S.; Grande, P.

    2008-01-01

    that has infarcted. There are no comparison of serial changes on ECG and DE-MRI measuring infarct size. AIM: The general aim of this study was to describe the acute, healing, and chronic phases of the changes in infarct size estimated by the ECG and DE-MRI. The specific aim was to compare estimates......INTRODUCTION: Magnetic resonance imaging using the delayed contrast-enhanced (DE-MRI) method can be used for characterizing and quantifying myocardial infarction (MI). Electrocardiogram (ECG) score after the acute phase of MI can be used to estimate the portion of left ventricular myocardium...... of the Selvester QRS scoring system and DE-MRI to identify the difference between the extent of left ventricle occupied by infarction in the acute and chronic phases. METHODS: In 31 patients (26 men, age 56 +/- 9) with reperfused ST-elevation MI (11 anterior, 20 inferior), standard 12-lead ECG and DE-MRI were...

  16. Why cold water delays the onset of vestibular vertigo-An functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhi [Department of Radiology, Beijing Hospital, No. 1 Dahua Road Dongdan, Beijing 100730 (China)], E-mail: zhiwang76@gmail.com; Chen Min [Department of Radiology, Beijing Hospital, No. 1 Dahua Road Dongdan, Beijing 100730 (China); Gong Xia; Huang Weining [Department of E.N.T., Beijing Hospital, No. 1 Dahua Road Dongdan, Beijing 100730 (China); Xu Liang [Department of Radiology, Beijing Hospital, No. 1 Dahua Road Dongdan, Beijing 100730 (China); Zhou Cheng [Department of Radiology, Beijing Hospital, No. 1 Dahua Road Dongdan, Beijing 100730 (China)], E-mail: chengzhou2000@yahoo.com

    2008-09-15

    The mechanism of vertigo is unclear. Generally, the peak time or the latency of blood oxygenation level dependent (BOLD) effect is about 6 s. However, clinically, the latency of vertigo or nystagmus induced by caloric stimulations is much longer than 6 s, commonly about 30 s induced by water of 30 deg. C or 44 deg. C. We hypothesize that there is an inhibitive power or mechanism for the occurrence of vestibular vertigo, since it is an unpleasant feeling. The caloric test was performed in healthy volunteers during the BOLD fMRI scanning. The overlaid results of statistical parametric mapping (SPM) showed that three brain regions showed neural activation during vestibular dizziness while deactivation occurred in response to cold water simulation: (1) supplementary motor area (SMA); (2) middle temporal area/medial superior temporal area (MT/MST); (3) visual association area (BA19). The time course of the regions further demonstrated that the signal decreased during the cold-water stimulation and increased during the period of vertigo. We therefore further hypothesize that there may be two forces for the production of vertigo: inhibitory power (IP) and promotive power (PP). The delayed onset of vertigo was the result of the interaction between IP and PP. All of our findings, for the first time, suggested such an original mechanism of vertigo.

  17. MRI Background Parenchymal Enhancement Is Not Associated with Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Barbara Bennani-Baiti

    Full Text Available Previously, a strong positive association between background parenchymal enhancement (BPE at magnetic resonance imaging (MRI and breast cancer was reported in high-risk populations. We sought to determine, whether this was also true for non-high-risk patients.540 consecutive patients underwent breast MRI for assessment of breast findings (BI-RADS 0-5, non-high-risk screening (no familial history of breast cancer, no known genetic mutation, no prior chest irradiation, or previous breast cancer diagnosis and subsequent histological work-up. For this IRB-approved study, BPE and fibroglandular tissue FGT were retrospectively assessed by two experienced radiologists according to the BI-RADS lexicon. Pearson correlation coefficients were calculated to explore associations between BPE, FGT, age and final diagnosis of breast cancer. Subsequently, multivariate logistic regression analysis, considering covariate colinearities, was performed, using final diagnosis as the target variable and BPE, FGT and age as covariates.Age showed a moderate negative correlation with FGT (r = -0.43, p<0.001 and a weak negative correlation with BPE (r = -0.28, p<0.001. FGT and BPE correlated moderately (r = 0.35, p<0.001. Final diagnosis of breast cancer displayed very weak negative correlations with FGT (r = -0.09, p = 0.046 and BPE (r = -0.156, p<0.001 and weak positive correlation with age (r = 0.353, p<0.001. On multivariate logistic regression analysis, the only independent covariate for prediction of breast cancer was age (OR 1.032, p<0.001.Based on our data, neither BPE nor FGT independently correlate with breast cancer risk in non-high-risk patients at MRI. Our model retained only age as an independent risk factor for breast cancer in this setting.

  18. Numerical Investigation of Noise Enhanced Stability Phenomenon in a Time-Delayed Metastable System

    Institute of Scientific and Technical Information of China (English)

    JIA Zheng-Lin

    2008-01-01

    @@ The transient properties of a time-delayed metastable system subjected to the additive white noise are investigated by means of the stochastic simulation method. The noise enhanced stability phenomenon (NES) can be observed in this system and the effect of the delay time on the NES shows a critical behaviour, i.e., there is a critical value of the delay time Tc ≈ 1, above which the time delay enhances the NES effect with the delay time increasing and below which the time delay weakens the NES effect as the delay time increases.

  19. Construction of 0.15 Tesla Overhauser Enhanced MRI.

    Science.gov (United States)

    Tokunaga, Yuumi; Nakao, Motonao; Naganuma, Tatsuya; Ichikawa, Kazuhiro

    2017-01-01

    Overhauser enhanced MRI (OMRI) is one of the free radical imaging technologies and has been used in biomedical research such as for partial oxygen measurements in tumor, and redox status in acute oxidative diseases. The external magnetic field of OMRI is frequently in the range of 5-10 mTesla to ensure microwave penetration into small animals, and the S/N ratio is limited. In this study, a 0.15 Tesla OMRI was constructed and tested to improve the S/N ratio for a small sample, or skin measurement. Specification of the main magnet was as follows: 0.15 Tesla permanent magnet; gap size 160 mm; homogenous spherical volume of 80 mm in diameter. The OMRI resonator was designed based on TE101 cavity mode and machined from a phosphorus deoxidized copper block for electron spin resonance (ESR) excitation and a solenoid transmission/receive resonator for NMR detection. The resonant frequencies and Q values were 6.38 MHz/150 and 4.31-4.41 GHz/120 for NMR and ESR, respectively. The Q values were comparable to those of conventional low field OMRI resonators at 15 mTesla. As expected, the MRI S/N ratio was improved by a factor of 30. Triplet dynamic nuclear polarization spectra were observed for (14)N carboxy-PROXYL, along the excitation microwave sweep. In the current setup, the enhancement factor was ca. 0.5. In conclusion, the results of this preliminary evaluation indicate that the 0.15 Tesla OMRI could be useful for free radical measurement for small samples.

  20. Differentiation of breast cancer from fibroadenoma with dual-echo dynamic contrast-enhanced MRI.

    Directory of Open Access Journals (Sweden)

    Shiwei Wang

    Full Text Available Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI of the breast is a routinely used imaging method which is highly sensitive for detecting breast malignancy. Specificity, though, remains suboptimal. Dynamic susceptibility contrast magnetic resonance imaging (DSC MRI, an alternative dynamic contrast imaging technique, evaluates perfusion-related parameters unique from DCE MRI. Previous work has shown that the combination of DSC MRI with DCE MRI can improve diagnostic specificity, though an additional administration of intravenous contrast is required. Dual-echo MRI can measure both T1W DCE MRI and T2*W DSC MRI parameters with a single contrast bolus, but has not been previously implemented in breast imaging. We have developed a dual-echo gradient-echo sequence to perform such simultaneous measurements in the breast, and use it to calculate the semi-quantitative T1W and T2*W related parameters such as peak enhancement ratio, time of maximal enhancement, regional blood flow, and regional blood volume in 20 malignant lesions and 10 benign fibroadenomas in 38 patients. Imaging parameters were compared to surgical or biopsy obtained tissue samples. Receiver operating characteristic (ROC curves and area under the ROC curves were calculated for each parameter and combination of parameters. The time of maximal enhancement derived from DCE MRI had a 90% sensitivity and 69% specificity for predicting malignancy. When combined with DSC MRI derived regional blood flow and volume parameters, sensitivity remained unchanged at 90% but specificity increased to 80%. In conclusion, we show that dual-echo MRI with a single administration of contrast agent can simultaneously measure both T1W and T2*W related perfusion and kinetic parameters in the breast and the combination of DCE MRI and DSC MRI parameters improves the diagnostic performance of breast MRI to differentiate breast cancer from benign fibroadenomas.

  1. Prediction of myocardial recovery by dobutamine magnetic resonance imaging and delayed enhancement early after reperfused acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Barmeyer, Achim A.; Muellerleile, Kai; Heuer, Mirko; Meinertz, Thomas; Lund, Gunnar K. [University Heart-Center, University Hospital Hamburg-Eppendorf, Clinic of Cardiology/Angiology, Hamburg (Germany); Stork, Alexander; Bansmann, Martin; Adam, Gerhard [University Hospital Hamburg-Eppendorf, Clinic of Diagnostic and Interventional Radiology, Hamburg (Germany); Bavastro, Markus [University Hospital Hamburg-Eppendorf, Clinic of Anaesthesiology, Hamburg (Germany)

    2008-01-15

    The purpose was to study dobutamine magnetic resonance cine imaging (DOB-MRI) and delayed myocardial contrast enhancement (DE) early after reperfused acute myocardial infarction (AMI) for the prediction of segmental myocardial recovery and to find the optimal dose of dobutamine. Fifty patients (56{+-}12 years, 42 males) with reperfused AMI underwent DOB-MRI and DE studies 3.5 (1-19) days after reperfusion. In DOB-MRI systolic wall thickening (SWT) was measured in 18 segments at rest and during dobutamine at 5, 10 and 20 {mu}g*kg{sup -1}*min{sup -1}. Dysfunctional segments were identified and the extent of DE was measured for each segment. Segmental recovery was examined after 8 (5-15) months. Two hundred-forty-eight segments were dysfunctional with presence of DE in 193. DOB-MRI showed the best prediction of recovery at 10 {mu}g*kg{sup -1}*min{sup -1} of dobutamine with sensitivity of 67%, specificity of 63% and accuracy of 66% using a cut-off value for SWT of 2.0 mm. DE revealed a sensitivity of 68%, specificity of 65% and accuracy of 67% using a cut-off value of 46%. Combined analysis of DOB-MRI and DE did not improve diagnostic performance. Early prediction of segmental myocardial recovery after AMI is possible with DOB-MRI and DE. No improvement is achieved by dobutamine >10 {mu}g*kg{sup -1}*min{sup -1} or a combination of DOB-MRI and DE. (orig.)

  2. Abducens nerve enhancement demonstrated by multiplanar reconstruction of contrast-enhanced three-dimensional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Hosoya, T.; Adachi, M.; Sugai, Y. [Dept. of Radiology, Yamagata University School of Medicine (Japan); Yamaguchi, K.; Yamaguchi, K. [Dept. of Ophthalmology, Yamagata University School of Medicine (Japan); Kato, T. [3. Dept. of Internal Medicine, Yamagata University School of Medicine (Japan)

    2001-04-01

    We describe contrast enhancement of the cisternal portion of the abducens nerve and discuss its clinical significance. We examined 67 patients with ophthalmoplegia using contrast-enhanced 3-dimensional (3D) MRI with multiplanar reconstruction along the nerves and found 16 patients (ten men, six women), aged 10-73 years (mean 34.4 years), with contrast enhancement of the abducens nerve. Of the 36 patients who had an abducens palsy, 14 (39 %) showed contrast enhancement. In the 16 patients, 23 abducens nerves enhanced; 13 were symptomatic and 10 asymptomatic at the time. The causes were disseminated tumour (1), an inflammatory process (3), trauma (2), ischaemia (2) and autoimmune diseases (8), such as the Miller Fisher syndrome, acute ophthalmoparesis, polyneuropathy and multiple sclerosis. Abducens and/or oculomotor nerve enhancement was the only abnormality on MRI in the patients with traumatic or ischaemic neuropathy or autoimmune diseases. There were 14 patients who recovered fully within 1-6 months after treatment, and resolution of the enhancement correlated well with recovery. (orig.)

  3. In vivo manganese-enhanced MRI for visuotopic brain mapping.

    Science.gov (United States)

    Chan, Kevin C; Wu, Ed X

    2012-01-01

    This study explored the feasibility of localized manganese-enhanced MRI (MEMRI) via 3 different routes of Mn(2+) administrations for visuotopic brain mapping of retinal, callosal, cortico-subcortical, transsynaptic and horizontal connections in normal adult rats. Upon fractionated intravitreal Mn(2+) injection, Mn enhancements were observed in the contralateral superior colliculus (SC) and lateral geniculate nucleus (LGN) by 45-60% at 1-3 days after initial Mn(2+) injection and in the contralateral primary visual cortex (V1) by about 10% at 2-3 days after initial Mn(2+) injection. Direct, single-dose Mn(2+) injection to the LGN resulted in Mn enhancement by 13-21% in V1 and 8-11% in SC of the ipsilateral hemisphere at 8 to 24 hours after Mn(2+) administration. Intracortical, single-dose Mn(2+) injection to the visual cortex resulted in Mn enhancement by 53-65% in ipsilateral LGN, 15-26% in ipsilateral SC, 32-34% in the splenium of corpus callosum and 17-25% in contralateral V1/V2 transition zone at 8 to 24 hours after Mn(2+) administration. Notably, some patchy patterns were apparent near the V1/V2 border of the contralateral hemisphere. Laminar-specific horizontal cortical connections were also observed in the ipsilateral hemisphere. The current results demonstrated the sensitivity of MEMRI for assessing the neuroarchitecture of the visual brains in vivo without depth-limitation, and may possess great potentials for studying the basic neural components and connections in the visual system longitudinally during development, plasticity, pharmacological interventions and genetic modifications.

  4. Small-bowel MRI in children and young adults with Crohn disease: retrospective head-to-head comparison of contrast-enhanced and diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, Henning; Evangelista, Laura; Wirth, Clemens; Beer, Meinrad [University Hospital Wuerzburg, Institute of Radiology, Department of Paediatric Radiology, Wuerzburg (Germany); Pabst, Thomas; Machann, Wolfram; Koestler, Herbert; Hahn, Dietbert [University Hospital Wuerzburg, Institute of Radiology, Wuerzburg (Germany); Dick, Anke [University Hospital Wuerzburg, Department of Paediatrics, Wuerzburg (Germany)

    2013-01-15

    Small-bowel MRI based on contrast-enhanced T1-weighted sequences has been challenged by diffusion-weighted imaging (DWI) for detection of inflammatory bowel lesions and complications in patients with Crohn disease. To evaluate free-breathing DWI, as compared to contrast-enhanced MRI, in children, adolescents and young adults with Crohn disease. This retrospective study included 33 children and young adults with Crohn disease ages 17 {+-} 3 years (mean {+-} standard deviation) and 27 matched controls who underwent small-bowel MRI with contrast-enhanced T1-weighted sequences and DWI at 1.5 T. The detectability of Crohn manifestations was determined. Concurrent colonoscopy as reference was available in two-thirds of the children with Crohn disease. DWI and contrast-enhanced MRI correctly identified 32 and 31 patients, respectively. All 22 small-bowel lesions and all Crohn complications were detected. False-positive findings (two on DWI, one on contrast-enhanced MRI), compared to colonoscopy, were a result of large-bowel lumen collapse. Inflammatory wall thickening was comparable on DWI and contrast-enhanced MRI. DWI was superior to contrast-enhanced MRI for detection of lesions in 27% of the assessed bowel segments and equal to contrast-enhanced MRI in 71% of segments. DWI facilitates fast, accurate and comprehensive workup in Crohn disease without the need for intravenous administration of contrast medium. Contrast-enhanced MRI is superior in terms of spatial resolution and multiplanar acquisition. (orig.)

  5. Early-enhancing non-neoplastic lesions on gadolinium-enhanced MRI of the liver

    Energy Technology Data Exchange (ETDEWEB)

    Kanematsu, M. E-mail: masa-gif@umin.ac.jp; Kondo, H.; Semelka, R.C.; Matsuo, M.; Goshima, S.; Hoshi, H.; Moriyama, N.; Itai, Y

    2003-10-01

    AIM: To assess the frequency, cause, and significance of early-enhancing, non-neoplastic (EN) lesions on gadolinium-enhanced magnetic resonance imaging (MRI) of the liver performed for the detection of malignant hepatic tumours. MATERIALS AND METHODS: From September 1997 to September 2000, we reviewed the images of 125 patients, suspected of having hepatic tumours, in whom (1) gadolinium-enhanced triphasic dynamic gradient-recalled-echo (GRE) imaging in addition to unenhanced T1- and T2-weighted MRI was performed, (2) conventional angiography and combination computed tomography (CT) hepatic arteriography and CT during arterial portography were performed within 2 weeks of the MRI, and (3) definitive surgery within 2 weeks of the MRI or follow-up study by means of intravenously contrast-enhanced CT or MRI in 10 months or more was performed. Angiographic studies were correlated to determine the underlying causes of the EN lesions. RESULTS: We found 78 EN lesions in 36 patients (29%), ranging in size from 4 and 50 mm (mean, 12.2 mm). From the MR reports, our radiologists had prospectively diagnosed EN lesions as probable malignant tumours in eight (10%), possible malignant tumours in 36 (46%), and probable non-neoplastic lesion in 34 (44%). EN lesions were found in 27 of 81 (33%) cirrhotic patients and in nine of 44 (20%) non-cirrhotic patients. Fifty-one EN lesions (65%) were located along the liver edge. The shape was circular in 42 (54%), oval in 14 (18%), irregular in 12 (15%), wedge-shaped in seven (9%), and fan-shaped in three (4%). Twenty EN lesions (26%) appeared slightly hyperintense on T2-weighted images. The causes were non-neoplastic arterio-portal shunting in 48 (62%), cystic venous drainage in four (5%), rib compression in four (5%), aberrant right gastric venous drainage in two (3%), and unknown in 20 (26%). CONCLUSION: Over half the number of EN lesions were caused by non-neoplastic arterio-portal shunting, occasionally showing slight hyperintensity on

  6. Detection of Cortical Laminar Architecture Using Manganese-Enhanced MRI

    Science.gov (United States)

    Silva, Afonso C.; Lee, Junghee; Wu, Carolyn W.-H.; Tucciarone, Jason; Pelled, Galit; Aoki, Ichio; Koretsky, Alan P.

    2008-01-01

    Changes in Manganese-Enhanced MRI (MEMRI) contrast across the rodent somatosensory cortex were compared to the cortical laminae as identified by tissue histology and administration of an anatomical tracer to cortex and thalamus. Across the cortical thickness, MEMRI signal intensity was low in layer I, increased in layer II, decreased in layer III until mid-layer IV, and increased again, peaking in layer V, before decreasing through layer VI. The reeler mouse mutant was used to confirm that the cortical alternation in MEMRI contrast was related to laminar architecture. Unlike in wild-type mice, the reeler cortex showed no appreciable changes in MEMRI signal, consistent[ACS1] with absence of cortical laminae in histological slides. The tract-tracing ability of MEMRI was used to further confirm assignments and demonstrate laminar specificity. Twelve to sixteen hours after stereotaxic injections of MnCl2 to the ventroposterior thalamic nuclei, an overall increase in signal intensity was detected in primary somatosensory cortex compared to other brain regions. Maximum intensity projection images revealed a distinctly bright stripe located 600 − 700 μm below the pial surface, in layer IV. The data show that both systemic and tract-tracing forms of MEMRI are useful for studying laminar architecture in the brain. PMID:17936913

  7. Development and optimization of hardware for delta relaxation enhanced MRI.

    Science.gov (United States)

    Harris, Chad T; Handler, William B; Araya, Yonathan; Martínez-Santiesteban, Francisco; Alford, Jamu K; Dalrymple, Brian; Van Sas, Frank; Chronik, Blaine A; Scholl, Timothy J

    2014-10-01

    Delta relaxation enhanced magnetic resonance (dreMR) imaging requires an auxiliary B0 electromagnet capable of shifting the main magnetic field within a clinical 1.5 Tesla (T) MR system. In this work, the main causes of interaction between an actively shielded, insertable resistive B0 electromagnet and a 1.5T superconducting system are systematically identified and mitigated. The effects of nonideal fabrication of the field-shifting magnet are taken into consideration through careful measurement during winding and improved accuracy in the design of the associated active shield. The shielding performance of the resultant electromagnet is compared against a previously built system in which the shield design was based on an ideal primary coil model. Hardware and software approaches implemented to eliminate residual image artifacts are presented in detail. The eddy currents produced by the newly constructed dreMR system are shown to have a significantly smaller "long-time-constant" component, consistent with the hypothesis that less energy is deposited into the cryostat of the MR system. With active compensation, the dreMR imaging system is capable of 0.22T field shifts within a clinical 1.5T MRI with no significant residual eddy-current fields. Copyright © 2013 Wiley Periodicals, Inc.

  8. Dynamic contrast-enhanced MRI for monitoring response to neoadjuvant chemotherapy in breast cancer

    NARCIS (Netherlands)

    Loo, C.E.

    2016-01-01

    The general aim of this thesis is to investigate the role of dynamic contrast-enhanced MRI in monitoring response of breast cancer during neoadjuvant chemotherapy. The role of MRI with respect to achieving personalized breast cancer treatment by improving response monitoring is examined. Our finding

  9. Comparison of dynamic susceptibility contrast-MRI perfusion quantification methods in the presence of delay and dispersion

    Science.gov (United States)

    Maan, Bianca; Simões, Rita Lopes; Meijer, Frederick J. A.; Klaas Jan Renema, W.; Slump, Cornelis H.

    2011-03-01

    The perfusion of the brain is essential to maintain brain function. Stroke is an example of a decrease in blood flow and reduced perfusion. During ischemic stroke the blood flow to tissue is hampered due to a clot inside a vessel. To investigate the recovery of stroke patients, follow up studies are necessary. MRI is the preferred imaging modality for follow up because of the absence of radiation dose concerns, contrary to CT. Dynamic Susceptibility Contrast (DSC) MRI is an imaging technique used for measuring perfusion of the brain, however, is not standard applied in the clinical routine due to lack of immediate patient benefit. Several post processing algorithms are described in the literature to obtain cerebral blood flow (CBF). The quantification of CBF relies on the deconvolution of a tracer concentration-time curve in an arterial and a tissue voxel. There are several methods to obtain this deconvolution based on singular-value decomposition (SVD). This contribution describes a comparison between the different approaches as currently there is no best practice for (all) clinical relevant situations. We investigate the influence of tracer delay, dispersion and recirculation on the performance of the methods. In the presence of negative delays, the truncated SVD approach overestimates the CBF. Block-circulant and reformulated SVD are delay-independent. Due to its delay dependent behavior, the truncated SVD approach performs worse in the presence of dispersion as well. However all SVD approaches are dependent on the amount of dispersion. Moreover, we observe that the optimal truncation parameter varies when recirculation is added to noisy data, suggesting that, in practice, these methods are not immune to tracer recirculation. Finally, applying the methods to clinical data resulted in a large variability of the CBF estimates. Block-circulant SVD will work in all situations and is the method with the highest potential.

  10. Enhanced MRI in lumbar disc herniation. Study on the types of herniation and histological findings

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Sadao; Okamura, Yuji; Honda, Eiichiro; Takazawa, Shunji [Misato Junshin Hospital, Saitama (Japan); Ohno, Ryuichi; Yasuma, Tsuguo

    1999-06-01

    In the cases which had surgery after enhanced MRI, prolapsed form of hernia and the usefulness of enhanced MRI were examined. The patients were 13 males (14 intervertebral discs) and 5 females (6 intervertebral discs) with lumber disc herniation. The lumber disc herniation was classified into 3 types reference to Macnab's classification; SE (protrusion and subligamentous extrusion), TE (transligamentous extrusion) and SEQ (sequestration). Prolapsed forms were identified in 20 intervertebral discs. Enhanced MRI showed positive in 9 intervertebral discs (SE 1, TE 4 and SEQ 4) and showed negative in 11 discs (SE 10 and TE 1). As for the period from development to enhanced MRI, the significant difference wasn't recognized between positive group and negative group. The diagnostic rate of enhanced MRI was 88.9% (8/9) in sensitivity, 90.9% (10/11) in specificity and 90.0% (18/20) in accuracy. In enhanced MRI, engorged epidural venous plexus was also imaged, and minute change as only annular tear couldn't be detected. Looking from 2 directions crossing at right angles, the effect of contrast enhancement should be judged. (K.H.)

  11. MRI

    Science.gov (United States)

    MRI does not use ionizing radiation. No side effects from the magnetic fields and radio waves have been reported. The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions rarely ...

  12. Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

    Energy Technology Data Exchange (ETDEWEB)

    Demi, Libertario, E-mail: l.demi@tue.nl; Sloun, Ruud J. G. van; Mischi, Massimo [Lab. of Biomedical Diagnostics, Dept. of Electrical Eng., Eindhoven University of Technology (Netherlands); Wijkstra, Hessel [Lab. of Biomedical Diagnostics, Dept. of Electrical Eng., Eindhoven University of Technology (Netherlands); Academic Medical Center, Urology Dept., University of Amsterdam (Netherlands)

    2015-10-28

    Recently, a new acoustic marker for ultrasound contrast agents (UCAs) has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental pressure wave field components is in fact observable for ultrasound propagating through UCAs. This phenomenon is absent in the case of tissue nonlinearity and is dependent on insonating pressure and frequency, UCA concentration, and propagation path length through UCAs. In this paper, ultrasound images based on this marker are presented. The ULA-OP research platform, in combination with a LA332 linear array probe (Esaote, Firenze Italy), were used to image a gelatin phantom containing a PVC plate (used as a reflector) and a cylindrical cavity measuring 7 mm in diameter (placed in between the observation point and the PVC plate). The cavity contained a 240 µL/L SonoVueO{sup ®} UCA concentration. Two insonating frequencies (3 MHz and 2.5 MHz) were used to scan the gelatine phantom. A mechanical index MI = 0.07, measured in water at the cavity location with a HGL-0400 hydrophone (Onda, Sunnyvale, CA), was utilized. Processing the ultrasound signals backscattered from the plate, ultrasound images were generated in a tomographic fashion using the filtered back-projection method. As already observed in previous studies, significantly higher CPD values are measured when imaging at a frequency of 2.5 MHz, as compared to imaging at 3 MHz. In conclusion, these results confirm the applicability of the discussed CPD as a marker for contrast imaging. Comparison with standard contrast-enhanced ultrasound imaging modalities will be the focus of future work.

  13. Contrast-enhanced MRI features in the early diagnosis of Juvenile Idiopathic Arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Hemke, Robert; Maas, Mario [University of Amsterdam, Department of Radiology Academic Medical Center, Amsterdam (Netherlands); Kuijpers, Taco W.; Schonenberg-Meinema, Dieneke [University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Nusman, Charlotte M. [University of Amsterdam, Department of Radiology Academic Medical Center, Amsterdam (Netherlands); University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Rossum, Marion A.J. van; Berg, J.M. van den [University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Department of Pediatric Rheumatology, Reade, Amsterdam (Netherlands); Dolman, Koert M. [Department of Pediatric Rheumatology, Reade, Amsterdam (Netherlands); St. Lucas Andreas Hospital, Department of Pediatrics, Amsterdam (Netherlands)

    2015-11-15

    To determine whether clinical, laboratory or Magnetic Resonance Imaging (MRI) measures differentiate Juvenile Idiopathic Arthritis (JIA) from other forms of active childhood arthritis. We prospectively collected data of 80 treatment-naive patients clinically suspected of JIA with active non-infectious arthritis of (at least) one knee for <12 months duration. Upon presentation patients underwent clinical and laboratory assessments and contrast-enhanced MRI. MRI was not used as a diagnostic criterion. Forty-four (55 %) patients were clinically diagnosed with JIA, whereas in 36 (45 %) patients the diagnosis of JIA was discarded on clinical or laboratory findings. MRI-based synovitis was present in 27 (61.4 %) JIA patients and in 7 (19.4 %) non-JIA patients (P < 0.001). Five factors (male gender, physician's global assessment of overall disease activity, joints with limited range of motion, HLA-B27, MRI-based synovitis) were associated with the onset of JIA. In multivariate analysis MRI-based synovitis proved to be independently associated with JIA (OR 6.58, 95 % CI 2.36-18.33). In patients with MRI-based synovitis, the RR of having JIA was 3.16 (95 % CI 1.6-6.4). The presence of MRI-based synovitis is associated with the clinical onset of JIA. Physical examination could be supported by MRI, particularly to contribute in the early differentiation of different forms of non-infectious childhood arthritis. (orig.)

  14. Spurious leptomeningeal enhancement on immediate post-operative MRI for paediatric brain tumours

    Energy Technology Data Exchange (ETDEWEB)

    Widjaja, Elysa; Connolly, Daniel J.A. [Royal Hallamshire Hospital, Department of Radiology, Sheffield (United Kingdom); Gatscher, Sylvia; McMullen, John [Royal Hallamshire Hospital, Department of Neurosurgery, Sheffield (United Kingdom); Griffiths, Paul D. [University of Sheffield, Academic section of Radiology, Sheffield (United Kingdom)

    2005-03-01

    Immediate post-operative MRI has been recommended as an accurate and robust method to assess residual brain tumour. Early enhancement at the resection margin and in the dura is well recognized, but we describe two cases of enhancement in the basal cisterns on immediate post-operative MRI that resolved on follow-up. The underlying cause of the enhancement remains to be elucidated, but it should be recognized that leptomeningeal enhancement may occur after surgery and that this does not necessarily imply tumour spread. (orig.)

  15. Major mouse placental compartments revealed by diffusion-weighted MRI, contrast-enhanced MRI, and fluorescence imaging.

    Science.gov (United States)

    Solomon, Eddy; Avni, Reut; Hadas, Ron; Raz, Tal; Garbow, Joel Richard; Bendel, Peter; Frydman, Lucio; Neeman, Michal

    2014-07-15

    Mammalian models, and mouse studies in particular, play a central role in our understanding of placental development. Magnetic resonance imaging (MRI) could be a valuable tool to further these studies, providing both structural and functional information. As fluid dynamics throughout the placenta are driven by a variety of flow and diffusion processes, diffusion-weighted MRI could enhance our understanding of the exchange properties of maternal and fetal blood pools--and thereby of placental function. These studies, however, have so far been hindered by the small sizes, the unavoidable motions, and the challenging air/water/fat heterogeneities, associated with mouse placental environments. The present study demonstrates that emerging methods based on the spatiotemporal encoding (SPEN) of the MRI information can robustly overcome these obstacles. Using SPEN MRI in combination with albumin-based contrast agents, we analyzed the diffusion behavior of developing placentas in a cohort of mice. These studies successfully discriminated the maternal from the fetal blood flows; the two orders of magnitude differences measured in these fluids' apparent diffusion coefficients suggest a nearly free diffusion behavior for the former and a strong flow-based component for the latter. An intermediate behavior was observed by these methods for a third compartment that, based on maternal albumin endocytosis, was associated with trophoblastic cells in the interphase labyrinth. Structural features associated with these dynamic measurements were consistent with independent intravital and ex vivo fluorescence microscopy studies and are discussed within the context of the anatomy of developing mouse placentas.

  16. History of lumbar disc herniation with Gd-DPTA enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Iwahara, Toshihito; Satou, Toshikazu [Wakkanai Municipal Hospital, Hokkaido (Japan)

    1995-09-01

    The pathological changes of primary lumbar disc herniation was monitored on T1-weighted and Gd-weighted MR imagings. The subjects were 11 patients whose symptoms improved solely by conservative therapy. Herniated area on T1-weighted images (whole herniated area), enhanced herniated area on Gd-MRI (enhanced area), and non-enhanced herniated area on Gd-MRI (non-enhanced area) were calculated, and each proportion to the vertebral canal was assessed. Changes in herniated area was correlated with changes of enhanced area. Gd-MRI was found to be useful in predicting the prognosis of primary herniation, as well as in differentiating recurrent herniation and cicatricial tissues. (S.Y.).

  17. Contrast-enhanced MRI of murine myocardial infarction - part II

    NARCIS (Netherlands)

    Coolen, B.F.; Paulis, L.E.M.; Geelen, T.; Nicolay, K.; Strijkers, G.J.

    2012-01-01

    Mouse models are increasingly used to study the pathophysiology of myocardial infarction in vivo. In this area, MRI has become the gold standard imaging modality, because it combines high spatial and temporal resolution functional imaging with a large variety of methods to generate soft tissue contr

  18. Contrast-enhanced MRI of murine myocardial infarction - part II

    NARCIS (Netherlands)

    Coolen, B.F.; Paulis, L.E.M.; Geelen, T.; Nicolay, K.; Strijkers, G.J.

    2012-01-01

    Mouse models are increasingly used to study the pathophysiology of myocardial infarction in vivo. In this area, MRI has become the gold standard imaging modality, because it combines high spatial and temporal resolution functional imaging with a large variety of methods to generate soft tissue

  19. Three-dimensional evaluation of lumbar disc hernia and prediction of absorption by enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kawaji, Youichi; Uchiyama, Seiji [Niigata Univ. (Japan). School of Medicine; Yagi, Eiichi

    2001-07-01

    Both the spontaneous shrinkage and the disappearance of disc hernia have been confirmed through the use of computed tomography (CT) and magnetic resonance imaging (MRI). There is, however, no practical method to predict the likely absorption of the herniated mass. The objective of this study was to predict the spontaneous absorption of disc hernia by MRI, and to select the optimum treatment. The study involved 65 patients with lumbar disc hernias. Conservative treatment was carried out in 21 patients, while 44 patients underwent herniotomy. In the nonoperated patients, an MRI was taken both during the painful period, and shortly after pain remission. Hernial shrinkage was evaluated according to the decrease in the calculated volume, in addition to the decrease in hernial area, calculated by MRI. In the operated group, preoperative MRI enhancement, type of hernia, and invasion of granulation tissue in the histological specimens were studied. In the 21 nonoperated patients, the volume (mean {+-}SD) was 0.488{+-}208 cm{sup 3} (range, 0.197-0.931 cm{sup 3}) in the painful period and 0.214{+-}0.181 cm{sup 3} (range, 0.0-0.744 cm{sup 3}) in the remission period. This decrease in volume was statistically significant. There was also a greater decrease in hernias exhibiting positive enhancement by MRI. In the operated patients, hernias that penetrated the posterior longitudinal ligament (PLL) had high rates of preoperative enhancement, and these hernias showed invasion of granulation tissue with marked neovascularization. Positive enhancement by MRI confirms an ongoing absorption process. Enhanced MRI can be a good method for the prediction of spontaneous absorption of lumbar disc hernias. (author)

  20. Intrahepatic mass-forming cholangiocarcinoma: prognostic value of preoperative gadoxetic acid-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Jieun; Chung, Yong Eun; Kim, Myeong-Jin; Choi, Jin-Young [Yonsei University, College of Medicine, Department of Radiology, Research Institute of Radiological Science, Seoul (Korea, Republic of); Nahm, Ji Hae; Park, Young Nyun [Yonsei University, College of Medicine, Department of Pathology, Seoul (Korea, Republic of); Kim, Ha Yan [Yonsei University, College of Medicine, Biostatistics Collaboration Unit, Severance Hospital, Seoul (Korea, Republic of); Kim, Kyung-Sik [Yonsei University, College of Medicine, Department of General Surgery, Seoul (Korea, Republic of)

    2016-02-15

    To assess whether gadoxetic acid-enhanced MRI could be used as a prognostic factor for intrahepatic mass-forming cholangiocarcinomas (IMCCs). Forty-one patients with pathologically proven IMCCs who underwent preoperative gadoxetic acid-enhanced MRI were included. The signal intensity of the IMCCs on hepatobiliary phase (HBP) MRI was qualitatively analyzed by two radiologists, and categorized into intermediate or hypointense groups. Analysis of clinicopathological prognostic factors and correlations of imaging and histology were also performed. Survival time and time to recurrence (TTR) were analyzed. Of the 41 IMCCs, 23 were in the intermediate group and 18 were in the hypointense group on HBP MRI. IMCCs in the intermediate group were associated with shorter survival time (P = 0.048) and TTR (P = 0.002) than the IMCCs of the hypointense group. Only the intermediate group on HBP MRI had a significantly shorter TTR on multivariate analysis (P = 0.012). The IMCCs of the intermediate group showed a tendency for more abundant tumour fibrous stroma than those of the hypointense group (P = 0.027). The enhancement of IMCCs on HBP gadoxetic acid-enhanced MRI appears to correlate with tumour aggressiveness and outcomes due to the tumour fibrous stromal component. Thus, HBP images could be a useful prognostic factor for IMCCs after surgery. (orig.)

  1. Delayed effects of cortisol enhance fear memory of trace conditioning

    NARCIS (Netherlands)

    Cornelisse, S.; Ast, V.A. van; Joëls, M.; Kindt, M.

    2014-01-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distin

  2. Stress enhancement in the delayed yielding of colloidal gels

    NARCIS (Netherlands)

    Sprakel, J.H.B.; Lindstrom, S.B.; Kodger, T.E.; Weitz, D.A.

    2011-01-01

    Networks of aggregated colloidal particles are solidlike and can sustain an applied shear stress while exhibiting little or no creep; however, ultimately they will catastrophically fail. We show that the time delay for this yielding decreases in two distinct exponential regimes with applied stress.

  3. Delayed effects of cortisol enhance fear memory of trace conditioning

    NARCIS (Netherlands)

    Cornelisse, S.; Ast, V.A. van; Joëls, M.; Kindt, M.

    2014-01-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distin

  4. Gd-EOB-DTPA-enhanced 3.0-Tesla MRI findings for the preoperative detection of focal liver lesions: Comparison with iodine-enhanced multi-detector computed tomography

    Science.gov (United States)

    Park, Hyong-Hu; Goo, Eun-Hoe; Im, In-Chul; Lee, Jae-Seung; Kim, Moon-Jib; Kwak, Byung-Joon; Chung, Woon-Kwan; Dong, Kyung-Rae

    2012-12-01

    The safety of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) has been confirmed, but more study is needed to assess the diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in patients with a hepatocellular carcinoma (HCC) for whom surgical treatment is considered or with a metastatic hepatoma. Research is also needed to examine the rate of detection of hepatic lesions compared to multi-detector computed tomography (MDCT), which is used most frequently to localize and characterize a HCC. Gd-EOB-DTPA-enhanced MRI and iodine-enhanced MDCT imaging were compared for the preoperative detection of focal liver lesions. The clinical usefulness of each method was examined. The current study enrolled 79 patients with focal liver lesions who preoperatively underwent MRI and MDCT. In these patients, there was less than one month between the two diagnostic modalities. Imaging data were taken before and after contrast enhancement in both methods. To evaluate the images, we analyzed the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) in the lesions and the liver parenchyma. To compare the sensitivity of the two methods, we performed a quantitative analysis of the percentage signal intensity of the liver (PSIL) on a high resolution picture archiving and communication system (PACS) monitor (paired-samples t-test, p DTPA-enhanced MRI findings and the iodine-enhanced MDCT by using an adjusted x2 test. The SNRs, CNRs, and PSIL all had a greater detection rate in Gd-EOB-DTPA enhanced MRI than in iodine-enhanced MDCT. Hepatocyte-selective uptake was observed 20 minutes after the injection in the focal nodular hyperplasia (FNH, 9/9), adenoma (9/10), and highly-differentiated HCC (grade G1, 27/30). Rim enhancement was detected in all metastases (30/30). During the arterial and the delayed phases, good overall agreement between the gadoxetic-acid-enhanced MR and CT was observed (x2 test, p DTPA-enhanced MRI had a higher

  5. Small-bowel MRI in children and young adults with Crohn disease: retrospective head-to-head comparison of contrast-enhanced and diffusion-weighted MRI.

    Science.gov (United States)

    Neubauer, Henning; Pabst, Thomas; Dick, Anke; Machann, Wolfram; Evangelista, Laura; Wirth, Clemens; Köstler, Herbert; Hahn, Dietbert; Beer, Meinrad

    2013-01-01

    Small-bowel MRI based on contrast-enhanced T1-weighted sequences has been challenged by diffusion-weighted imaging (DWI) for detection of inflammatory bowel lesions and complications in patients with Crohn disease. To evaluate free-breathing DWI, as compared to contrast-enhanced MRI, in children, adolescents and young adults with Crohn disease. This retrospective study included 33 children and young adults with Crohn disease ages 17 ± 3 years (mean ± standard deviation) and 27 matched controls who underwent small-bowel MRI with contrast-enhanced T1-weighted sequences and DWI at 1.5 T. The detectability of Crohn manifestations was determined. Concurrent colonoscopy as reference was available in two-thirds of the children with Crohn disease. DWI and contrast-enhanced MRI correctly identified 32 and 31 patients, respectively. All 22 small-bowel lesions and all Crohn complications were detected. False-positive findings (two on DWI, one on contrast-enhanced MRI), compared to colonoscopy, were a result of large-bowel lumen collapse. Inflammatory wall thickening was comparable on DWI and contrast-enhanced MRI. DWI was superior to contrast-enhanced MRI for detection of lesions in 27% of the assessed bowel segments and equal to contrast-enhanced MRI in 71% of segments. DWI facilitates fast, accurate and comprehensive workup in Crohn disease without the need for intravenous administration of contrast medium. Contrast-enhanced MRI is superior in terms of spatial resolution and multiplanar acquisition.

  6. A Nanocomplex System as Targeted Contrast Agent Delivery Vehicle for MRI Dynamic Contrast Enhancement Study

    OpenAIRE

    Korotcov, Alexandru; Shan, Liang; Meng, Huan; Wang, Tongxin; Sridhar, Rajagopalan; Zhao, Yuliang; Liang, Xing-Jie; Wang, Paul C.

    2010-01-01

    We have developed and tested a liposomal nanocomplex system, which contains Gd-DTPA as a payload and transferrin on the surface, as a tumor specific targeting MRI contrast agent for studying prostate cancer tumors in mice. In vivo, the probe significantly enhanced the MRI signal. The image contrast between the peripheral region of the tumor and the non-involved muscle was nearly 50% higher two hours after administration of the nanocomplex. The liposomal nanocomplex increased the amount of Gd ...

  7. Contrast-Enhanced Abdominal MRI for Suspected Appendicitis: How We Do It

    Science.gov (United States)

    Kinner, Sonja; Repplinger, Michael D.; Pickhardt, Perry J.; Reeder, Scott B.

    2017-01-01

    OBJECTIVE The purpose of this article is to describe our approach to contrast-enhanced abdominal MRI in patients with nontraumatic abdominal pain and suspected appendicitis. We aim to share our experience on the advantages, pearls, and pitfalls of MRI in this clinical setting, in comparison with CT and ultrasound. CONCLUSION We present some typical cases of appendicitis and alternative diagnoses in patients presenting with acute nontraumatic abdominal pain. PMID:27065072

  8. Contrast-enhanced MRI of intrasellar arachnoid cysts: relationship between the pituitary gland and cyst

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, M. [National Cardiovascular Center, Osaka (Japan). Dept. of Neurosurgery]|[Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Tachibana, O. [Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Hasegawa, M. [Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Kohda, Y. [Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Nakada, M. [Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Yamashima, T. [Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Yamashita, J. [Kanazawa Univ. School of Medicine (Japan). Dept. of Neurosurgery; Suzuki, M. [Kanazawa Univ. School of Medicine (Japan). Dept. of Radiology

    1996-08-01

    We recently encountered two large intrasellar arachnoid cysts extending to the suprasellar region. The intensity of the cyst contents was identical to that of the cerebrospinal fluid on both T1- and T2-weighted MRI. On contrast-enhanced MRI, the pituitary gland was compressed posteroinferiorly and flattened in the sella turcica. In this report of rare intrasellar arachnoid cysts the discussion is focused on dislocation of the pituitary gland. (orig.)

  9. Detection and mapping of delays in early cortical folding derived from in utero MRI

    Science.gov (United States)

    Habas, Piotr A.; Rajagopalan, Vidya; Scott, Julia A.; Kim, Kio; Roosta, Ahmad; Rousseau, Francois; Barkovich, A. James; Glenn, Orit A.; Studholme, Colin

    2011-03-01

    Understanding human brain development in utero and detecting cortical abnormalities related to specific clinical conditions is an important area of research. In this paper, we describe and evaluate methodology for detection and mapping of delays in early cortical folding from population-based studies of fetal brain anatomies imaged in utero. We use a general linear modeling framework to describe spatiotemporal changes in curvature of the developing brain and explore the ability to detect and localize delays in cortical folding in the presence of uncertainty in estimation of the fetal age. We apply permutation testing to examine which regions of the brain surface provide the most statistical power to detect a given folding delay at a given developmental stage. The presented methodology is evaluated using MR scans of fetuses with normal brain development and gestational ages ranging from 20.57 to 27.86 weeks. This period is critical in early cortical folding and the formation of the primary and secondary sulci. Finally, we demonstrate a clinical application of the framework for detection and localization of folding delays in fetuses with isolated mild ventriculomegaly.

  10. Study delay and dispersion effects in dynamic susceptibility contrast MRI based on local density random walk distribution

    Science.gov (United States)

    Li, Xingfeng; Tian, Jie; Wang, Xiaoxiang; Dai, Jianping; Ai, Lin

    2004-04-01

    The aim of this study was to assess the validation of the local density random walk (LDRW) function to correct the delayed and dispersed arterial input function (AIF) data derived from dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Instead of using the gamma-variate function to smooth and extrapolate the AIF curves, we suggested a method which was based on diffusion with drift approach. Forty-seven AIF curves from ten patients were segmented to test the effectiveness of the proposed method. The results of the comparisons with the gamma-variate function showed that the LDRW distribution function may provide a new means for more accurate correction of AIF curves.

  11. Automatic Characterization of Myocardial Perfusion in Contrast Enhanced MRI

    Science.gov (United States)

    Positano, Vincenzo; Santarelli, Maria Filomena; Landini, Luigi

    2003-12-01

    The use of contrast medium in cardiac MRI allows joining the high-resolution anatomical information provided by standard magnetic resonance with functional information obtained by means of the perfusion of contrast agent in myocardial tissues. The current approach to perfusion MRI characterization is the qualitative one, based on visual inspection of images. Moving to quantitative analysis requires extraction of numerical indices of myocardium perfusion by analysis of time/intensity curves related to the area of interest. The main problem in quantitative image sequence analysis is the heart movement, mainly due to patient respiration. We propose an automatic procedure based on image registration, segmentation of the myocardium, and extraction and analysis of time/intensity curves. The procedure requires a minimal user interaction, is robust with respect to the user input, and allows effective characterization of myocardial perfusion. The algorithm was tested on cardiac MR images acquired from voluntaries and in clinical routine.

  12. Dynamic Contrast-Enhanced MRI for the Detection of Prostate Cancer: Meta-Analysis

    Science.gov (United States)

    Tan, Cher Heng; Hobbs, Brian Paul; Wei, Wei; Kundra, Vikas

    2016-01-01

    Objective The purpose of this study was to systematically review and meta-analyze dynamic contrast-enhanced MRI (DCE-MRI) for the detection of prostate cancer in comparison with standard evaluation with T2-weighted imaging. Materials and Methods A PubMed electronic database search for the terms “dynamic contrast-enhanced,” “prostate,” and “MRI” was completed for articles up to September 17, 2013. All included studies had histopathologic correlation. Two by two contingency data were constructed for each study. A binormal bayesian ROC model was used to estimate and compare sensitivity, specificity, and AUC among eligible modalities. Results Both DCE-MRI (0.82–0.86) and diffusion-weighted MRI (DWI) (0.84–0.88) yielded significantly better AUC than T2-weighted imaging (0.68–0.77). Moreover, partial AUC for the combination of DCE-MRI, DWI, and T2-weighted imaging was improved significantly (0.111; 0.103–0.119) when compared with DCE-MRI alone (0.079; 0.072–0.085) and T2-weighted imaging alone (0.079; 0.074–0.084) but not DWI alone (0.099; 0.091–0.108). Sensitivity and specificity were similar among the four modalities. Conclusion DCE-MRI improves AUC of tumor detection overall compared with T2-weighted imaging alone. Methods for DCE-MRI analysis require standardization, but visual analysis performs similar to semiquantitative methods. A two-parameter approach using DCE-MRI and T2-weighted imaging or DWI and T2-weighted imaging may be sufficient, and the latter may be more favorable for most routine prostate cancer imaging. PMID:25794093

  13. Background parenchymal enhancement on baseline screening breast MRI: impact on biopsy rate and short-interval follow-up.

    LENUS (Irish Health Repository)

    Hambly, Niamh M

    2011-01-01

    Background parenchymal enhancement on breast MRI refers to normal enhancement of the patient\\'s fibroglandular tissue. The aim of this study was to determine the effect of background parenchymal enhancement on short-interval follow-up, biopsy, and cancer detection rate on baseline screening MRI in a high-risk group.

  14. Signal enhancement ratio (SER) quantified from breast DCE-MRI and breast cancer risk

    Science.gov (United States)

    Wu, Shandong; Kurland, Brenda F.; Berg, Wendie A.; Zuley, Margarita L.; Jankowitz, Rachel C.; Sumkin, Jules; Gur, David

    2015-03-01

    Breast magnetic resonance imaging (MRI) is recommended as an adjunct to mammography for women who are considered at elevated risk of developing breast cancer. As a key component of breast MRI, dynamic contrast-enhanced MRI (DCE-MRI) uses a contrast agent to provide high intensity contrast between breast tissues, making it sensitive to tissue composition and vascularity. Breast DCE-MRI characterizes certain physiologic properties of breast tissue that are potentially related to breast cancer risk. Studies have shown that increased background parenchymal enhancement (BPE), which is the contrast enhancement occurring in normal cancer-unaffected breast tissues in post-contrast sequences, predicts increased breast cancer risk. Signal enhancement ratio (SER) computed from pre-contrast and post-contrast sequences in DCE-MRI measures change in signal intensity due to contrast uptake over time and is a measure of contrast enhancement kinetics. SER quantified in breast tumor has been shown potential as a biomarker for characterizing tumor response to treatments. In this work we investigated the relationship between quantitative measures of SER and breast cancer risk. A pilot retrospective case-control study was performed using a cohort of 102 women, consisting of 51 women who had diagnosed with unilateral breast cancer and 51 matched controls (by age and MRI date) with a unilateral biopsy-proven benign lesion. SER was quantified using fully-automated computerized algorithms and three SER-derived quantitative volume measures were compared between the cancer cases and controls using logistic regression analysis. Our preliminary results showed that SER is associated with breast cancer risk, after adjustment for the Breast Imaging Reporting and Data System (BI-RADS)-based mammographic breast density measures. This pilot study indicated that SER has potential for use as a risk factor for breast cancer risk assessment in women at elevated risk of developing breast cancer.

  15. Differences in perfusion parameters between upper and lower lumbar vertebral segments with dynamic contrast-enhanced MRI (DCE MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Savvopoulou, Vasiliki; Vlahos, Lampros; Moulopoulos, Lia Angela [University of Athens, Areteion Hospital, Department of Radiology, Medical School, Athens (Greece); Maris, Thomas G. [University of Crete, Deparment of Medical Physics, Faculty of Medicine, Heraklion (Greece)

    2008-09-15

    To investigate the influence of age, sex and spinal level on perfusion parameters of normal lumbar bone marrow with dynamic contrast-enhanced MRI (DCE MRI). Sixty-seven subjects referred for evaluation of low back pain or sciatica underwent DCE MRI of the lumbar spine. After subtraction of dynamic images, a region of interest (ROI) was placed on each lumbar vertebral body of all subjects, and time intensity curves were generated. Consequently, perfusion parameters were calculated. Statistical analysis was performed to search for perfusion differences among lumbar vertebrae and in relation to age and sex. Upper (L1, L2) and lower (L3, L4, L5) vertebrae showed significant differences in perfusion parameters (p<0.05). Vertebrae of subjects younger than 50 years showed significantly higher perfusion compared to vertebrae of older ones (p<0.05). Vertebrae of females demonstrated significantly increased perfusion compared to those of males of corresponding age (p<0.05). All perfusion parameters, except for washout (WOUT), showed a mild linear correlation with age. Time to maximum slope (TMSP) and time to peak (TTPK) showed the same correlation with sex (0.22

  16. Diagnostic performance of USPIO-enhanced MRI for lymph-node metastases in different body regions: A meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wu Liucheng [Department of Colorectal and Anal Surgery, First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi (China); Cao Yunfei, E-mail: caoyunfei126@126.com [Department of Colorectal and Anal Surgery, First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi (China); Liao Cun; Huang Jiahao [Department of Colorectal and Anal Surgery, First Affiliated Hospital, Guangxi Medical University, Nanning Guangxi (China); Gao Feng, E-mail: doctorgao0771@hotmail.com [Department of Colorectal and Anal Surgery, First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi (China)

    2011-11-15

    Objectives: USPIO (ultrasmall superparamagnetic iron oxide contrast agent) MRI was a promising imaging modality in the detection of lymph-node metastases. And this meta-analysis is performed to compare the diagnostic accuracy of USPIO-enhanced MRI with non-enhanced MRI, USPIO-enhanced MRI in various body regions, and postcontrast alone for diagnosis of lymph-node metastases. Methods: A comprehensive and systematic search was conducted in PubMed and EMBASE databases. After a systematic review of the studies, sensitivity, specificity, the Q* value and other measures of accuracy of USPIO-enhanced MRI in the diagnosis of lymph-node metastases were summarized. The overall test performance was based on summary receiver operating characteristic curves. Results: Summary of ROC curve analysis for per-lymph-node data shows a pooled sensitivity of 0.90 (95% confidential interval [CI]: 0.88-0.91) and overall specificity of 0.96 (95% CI: 0.95-0.97) for USPIO-enhanced MRI, the Q* value for USPIO-enhanced MRI is 0.9195, diagnostic odds ratio (DOR) is 162.28 (95% CI: 91.82-286.81). Non-enhanced MRI had less overall sensitivity 0.39 (95% CI: 0.34-0.43) and specificity 0.90 (95% CI: 0.89-0.91), respectively, the Q* value for USPIO-enhanced MRI was 0.6321, DOR is 5.81 (95% CI: 3.64-9.82). Postcontrast MRI alone had sensitivity 0.85 (95% CI: 0.81-0.88) and specificity 0.93 (95% CI: 0.91-0.95), respectively, the Q* value for USPIO-enhanced MRI was 0.8976, DOR is 76.92 (95% CI: 34.21-172.93). There was significant heterogeneity for studies reporting enhanced MRI and non-enhanced MRI. Conclusions: This meta-analysis has shown that USPIO-enhanced MRI offers higher diagnostic performance than conventional MRI, and is sensitive and specific for the detection of lymph-node metastases. Postcontrast images alone can equate diagnostic performance pre- and postcontrast MRI has achieved for lymph-node characterization. And the role of USPIO-enhanced MRI in clinical practice still needs to be

  17. Delay-enhanced coherence of spiral waves in noisy Hodgkin-Huxley neuronal networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qingyun [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China) and School of Statistics and Mathematics, Inner Mongolia Finance and Economics College, Huhhot 010051 (China)], E-mail: nmqingyun@163.com; Perc, Matjaz [Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroska cesta 160, SI-2000 Maribor (Slovenia); Duan Zhisheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Chen Guanrong [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Department of Electronic Engineering, City University of Hong Kong, Hong Kong (China)

    2008-08-25

    We study the spatial dynamics of spiral waves in noisy Hodgkin-Huxley neuronal ensembles evoked by different information transmission delays and network topologies. In classical settings of coherence resonance the intensity of noise is fine-tuned so as to optimize the system's response. Here, we keep the noise intensity constant, and instead, vary the length of information transmission delay amongst coupled neurons. We show that there exists an intermediate transmission delay by which the spiral waves are optimally ordered, hence indicating the existence of delay-enhanced coherence of spatial dynamics in the examined system. Additionally, we examine the robustness of this phenomenon as the diffusive interaction topology changes towards the small-world type, and discover that shortcut links amongst distant neurons hinder the emergence of coherent spiral waves irrespective of transmission delay length. Presented results thus provide insights that could facilitate the understanding of information transmission delay on realistic neuronal networks.

  18. Optimizing signal intensity correction during evaluation of hepatic parenchymal enhancement on gadoxetate disodium-enhanced MRI: Comparison of three methods

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Minori, E-mail: onoda@radt.med.kindai.ac.jp [Department of Radiological Technology, Kinki University Hospital, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Hyodo, Tomoko, E-mail: neneth@m.ehime-u.ac.jp [Department of Radiology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Murakami, Takamichi, E-mail: murakami@med.kindai.ac.jp [Department of Radiology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Okada, Masahiro, E-mail: okada777@med.u-ryukyu.ac.jp [Department of Radiology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Uto, Tatsuro, E-mail: chuho@med.kindai.ac.jp [Department of Radiological Technology, Kinki University Hospital, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Hori, Masatoshi, E-mail: mhori@radiol.med.osaka-u.ac.jp [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Miyati, Tosiaki, E-mail: ramiyati@mhs.mp.kanazawa-u.ac.jp [Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan)

    2015-03-15

    Highlights: •Signal intensity is often used to evaluate hepatic enhancement with Gd-EOB-DTPA in the hepatobiliary phase. •Comparison of uncorrected signal intensity with T{sub 1} value revealed signal intensity instability. •Measurement of uncorrected liver SI or SNR often yields erroneous results on late-phase gadoxetate MRI due to shimming and other optimization techniques. •Signal intensity corrected by scale and rescale slope from DICOM data gave comparable results. -- Abstract: Objective: To compare signal intensity (SI) correction using scale and rescale slopes with SI correction using SIs of spleen and muscle for quantifying multiphase hepatic contrast enhancement with Gd-EOB-DTPA by assessing their correlation with T{sub 1} values generated from Look-Locker turbo-field-echo (LL-TFE) sequence data (ER-T{sub 1}). Materials and methods: Thirty patients underwent Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in this prospective clinical study. For each patient, breath-hold T{sub 1}-weighted fat-suppressed three-dimensional (3D) gradient echo sequences (e-THRIVE) were acquired before and 2 (first phase), 10 (second phase), and 20 min (third phase) after intravenous Gd-EOB-DTPA. Look-Locker turbo-field-echo (LL-TFE) sequences were acquired before and 1.5 (first phase), 8 (second phase), and 18 min (third phase) postcontrast. The liver parenchyma enhancement ratios (ER) of each phase were calculated using the SI from e-THRIVE sequences (ER-SI) and the T{sub 1} values generated from LL-TFE sequence data (ER-T{sub 1}) respectively. ER-SIs were calculated in three ways: (1) comparing with splenic SI (ER-SI-s), (2) comparing with muscle SI (ER-SI-m), (3) using scale and rescale slopes obtained from DICOM headers (ER-SI-c), to eliminate the effects of receiver gain and scaling. For each of the first, second and third phases, correlation and agreement were assessed between each ER-SI and ER-T{sub 1}. Results: In the first phase, all ER-SIs correlated

  19. In vivo visuotopic brain mapping with manganese-enhanced MRI and resting-state functional connectivity MRI.

    Science.gov (United States)

    Chan, Kevin C; Fan, Shu-Juan; Chan, Russell W; Cheng, Joe S; Zhou, Iris Y; Wu, Ed X

    2014-04-15

    The rodents are an increasingly important model for understanding the mechanisms of development, plasticity, functional specialization and disease in the visual system. However, limited tools have been available for assessing the structural and functional connectivity of the visual brain network globally, in vivo and longitudinally. There are also ongoing debates on whether functional brain connectivity directly reflects structural brain connectivity. In this study, we explored the feasibility of manganese-enhanced MRI (MEMRI) via 3 different routes of Mn(2+) administration for visuotopic brain mapping and understanding of physiological transport in normal and visually deprived adult rats. In addition, resting-state functional connectivity MRI (RSfcMRI) was performed to evaluate the intrinsic functional network and structural-functional relationships in the corresponding anatomical visual brain connections traced by MEMRI. Upon intravitreal, subcortical, and intracortical Mn(2+) injection, different topographic and layer-specific Mn enhancement patterns could be revealed in the visual cortex and subcortical visual nuclei along retinal, callosal, cortico-subcortical, transsynaptic and intracortical horizontal connections. Loss of visual input upon monocular enucleation to adult rats appeared to reduce interhemispheric polysynaptic Mn(2+) transfer but not intra- or inter-hemispheric monosynaptic Mn(2+) transport after Mn(2+) injection into visual cortex. In normal adults, both structural and functional connectivity by MEMRI and RSfcMRI was stronger interhemispherically between bilateral primary/secondary visual cortex (V1/V2) transition zones (TZ) than between V1/V2 TZ and other cortical nuclei. Intrahemispherically, structural and functional connectivity was stronger between visual cortex and subcortical visual nuclei than between visual cortex and other subcortical nuclei. The current results demonstrated the sensitivity of MEMRI and RSfcMRI for assessing the

  20. Creatine Deficiency Syndrome could be Missed Easily: A Case Report of Guanidinoacetate Methyltransferase Deficiency Presented with Neurodevelopmental Delay, Seizures, and Behavioral Changes, but Normal Structural MRI.

    Science.gov (United States)

    Pacheva, Iliyana; Ivanov, Ivan; Penkov, Marin; Kancheva, Daliya; Jordanova, Albena; Ivanova, Mariya

    2016-09-01

    A case with GAMT deficiency (homozygous c.64dupG mutation) presented with neurodevelopmental delay, rare seizures, behavioral disturbances, and mild hypotonia, posing diagnostic challenges. Metabolic investigations showed low creatinine in plasma and urine (guanidinoacetate couldn't be investigated) and slightly elevated lactate. MRI was normal. Correct diagnosis was possible only after MR spectroscopy was performed at age 5½ years. A homozygous c.64dupG mutation of the GAMT gene was identified in the proband. In conclusion, every case with neurodevelopmental delay or arrest, especially when accompanied by seizures, behavioral impairment, muscle hypotonia or extrapyramidal symptoms should undergo MRI with MR spectroscopy. Normal structural MRI doesn't exclude a creatine deficiency syndrome. Biochemical investigations of guanidinoacetate, creatine, and creatinine in body fluid should be done to diagnose cerebral creatine deficiency syndromes and to specify the deficient enzyme. Thus, a treatable disease will not be missed.

  1. Synthesis and functionalization of Gd-based nanoparticles for MRI contrast enhancement

    OpenAIRE

    Skallberg, Andreas

    2011-01-01

    Magnetic metal oxide nanoparticles for contrast enhancement in Magnetic Resonance Imaging (MRI) have proven to be one of the most promising applications in diagnostic science. The nanoparticles can provide better and more accurate diagnosis by their capability to enhance the contrast between different soft tissues. New and better contrast agents need to be developed, to further improve this contrast enhancement. This thesis is focused on biofunctionalization of gadolinium oxide (Gd2O3) nanopa...

  2. Subdural enhancement on postoperative spinal MRI after resection of posterior cranial fossa tumours

    Energy Technology Data Exchange (ETDEWEB)

    Warmuth-Metz, M.; Solymosi, L. [Abteilung fuer Neuroradiologie, Klinikum der Bayerischen Julius Maximilians Universitaet, Josef-Schneider-Strasse 11, 97080, Wuerzburg (Germany); Kuehl, J. [Paediatric Oncology, Klinikum der Bayerischen Julius Maximilians Universitaet, Josef-Schneider-Strasse 11, 97080, Wuerzburg (Germany); Krauss, J. [Paediatric Neurosurgery, Klinikum der Bayerischen Julius Maximilians Universitaet, Josef-Schneider-Strasse 11, 97080, Wuerzburg (Germany)

    2004-03-01

    In malignant brain tumours which may disseminate staging, usually by cranial and spinal MRI is necessary. If MRI is performed in the postoperative period pitfalls should be considered. Nonspecific subdural contrast enhancement on spinal staging MRI is rarely reported after resection of posterior fossa tumours, which may be mistaken for dissemination of malignancy. We investigated the frequency of spinal subdural enhancement after posterior cranial fossa neurosurgery in children. We reviewed 53 postoperative spinal MRI studies performed for staging of paediatric malignant brain tumours, mainly infratentorial primitive neuroectodermal tumours 2-40 days after surgery. There was contrast enhancement in the spinal subdural space in seven cases. This was not seen in any of eight patients who had been operated upon for a supratentorial tumour. After resection of 45 posterior cranial fossa tumours the frequency of subdural enhancement was 15.5%. MRI showing subdural enhancement was obtained up to 25 days postoperatively. No patient with subdural enhancement had cerebrospinal fluid (CSF) examinations positive for tumour cells or developed dissemination of disease in the CSF. Because the characteristic appearances of subdural contrast enhancement, appropriate interpretation is possible; diagnosis of neoplastic meningitis should rarely be impeded. Because of the striking similarity to that in patients with a low CSF-pressure syndrome and in view of the fact that only resection of tumours of the posterior cranial fossa, usually associated with obstructive hydrocephalus, was followed by this type of enhancement one might suggest that rapid changes in CSF pressure are implicated, rather the effects of blood introduced into the spinal canal at surgery. (orig.)

  3. A pilot study to investigate the effect of a hydration regime upon immediate and 24 h delayed MRI contrast agent reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, William [Medical Imaging, Leighton Hospital, Mid Cheshire Hospital Trust, Middlewich Road, Crewe, Cheshire CW1 4QJ (United Kingdom)], E-mail: william.bailey@mcht.nhs.uk; Marshall, Gill [Chair of Faculty Academic Standards International Projects Leader, Faculty of Health and Social Care, St. Martin' s College, Lancaster LA1 3JD (United Kingdom); Coals, Jacqui [Medical Imaging, Leighton Hospital, Mid Cheshire Hospital Trust, Middlewich Road, Crewe, Cheshire CW1 4QJ (United Kingdom)

    2007-12-15

    Purpose: Adverse reaction rates to gadolinium based magnetic resonance imaging (MRI) contrast agents which occur immediately post-injection are well documented. However little research has investigated delayed reaction rates (i.e. 30 min-24 h). This study evaluated the rate of immediate and delayed adverse reaction rates to a gadolinium based MRI contrast agent (Dotarem) and investigated the effect of a hydration regime on the rate of adverse events. Method: Fifty-eight patients received no preparation, prior to administration of the contrast agent, whilst another 58 underwent a hydration protocol. The patients had their answers to a questionnaire recorded immediately after the scanning procedure and also via a follow-up telephone call 24 h later. Results: In the unprepared group 9 patients (15.5%) experienced immediate adverse events, i.e. within 0-30 min, whereas 24 (41.4%) experienced delayed reactions (30 min-24 h) after administration of the contrast agent. In the hydrated patient group 6 (10.3%) experienced an immediate adverse event, whilst 8 (13.7%) experienced delayed events post-injection. The difference in the total reaction rates for the unprepared and hydrated groups was statistically significant for immediate and delayed reactions. The difference in the rates of delayed headache, nausea, dizziness and problems with the injection site, for the unprepared and hydrated groups was statistically significant. Conclusion: An oral hydration regime administered to patients, both before and after MRI contrast agent administration significantly reduced the total number of immediate and delayed reactions. It also significantly reduced delayed headache, nausea, dizziness and problems at the injection site. Whilst this pilot study had methodological shortcomings, the strength of the relationship demonstrated are worthy of further investigation.

  4. Incorporating Oxygen-Enhanced MRI into Multi-Parametric Assessment of Human Prostate Cancer.

    Science.gov (United States)

    Zhou, Heling; Hallac, Rami R; Yuan, Qing; Ding, Yao; Zhang, Zhongwei; Xie, Xian-Jin; Francis, Franto; Roehrborn, Claus G; Sims, R Douglas; Costa, Daniel N; Raj, Ganesh V; Mason, Ralph P

    2017-08-24

    Hypoxia is associated with prostate tumor aggressiveness, local recurrence, and biochemical failure. Magnetic resonance imaging (MRI) offers insight into tumor pathophysiology and recent reports have related transverse relaxation rate (R₂*) and longitudinal relaxation rate (R₁) measurements to tumor hypoxia. We have investigated the inclusion of oxygen-enhanced MRI for multi-parametric evaluation of tumor malignancy. Multi-parametric MRI sequences at 3 Tesla were evaluated in 10 patients to investigate hypoxia in prostate cancer prior to radical prostatectomy. Blood oxygen level dependent (BOLD), tissue oxygen level dependent (TOLD), dynamic contrast enhanced (DCE), and diffusion weighted imaging MRI were intercorrelated and compared with the Gleason score. The apparent diffusion coefficient (ADC) was significantly lower in tumor than normal prostate. Baseline R₂* (BOLD-contrast) was significantly higher in tumor than normal prostate. Upon the oxygen breathing challenge, R₂* decreased significantly in the tumor tissue, suggesting improved vascular oxygenation, however changes in R₁ were minimal. R₂* of contralateral normal prostate decreased in most cases upon oxygen challenge, although the differences were not significant. Moderate correlation was found between ADC and Gleason score. ADC and R₂* were correlated and trends were found between Gleason score and R₂*, as well as maximum-intensity-projection and area-under-the-curve calculated from DCE. Tumor ADC and R₂* have been associated with tumor hypoxia, and thus the correlations are of particular interest. A multi-parametric approach including oxygen-enhanced MRI is feasible and promises further insights into the pathophysiological information of tumor microenvironment.

  5. Significance of Gd-DTPA enhanced MRI in lumbar disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Hijikuro, Taiji; Nakai, Osamu; Shindo, Shigeo; Mizuno, Kouichi; Otani, Kazuyuki; Yamaura, Isakichi [Kudanzaka Hospital, Tokyo (Japan)

    2001-04-01

    To know the significance of enhanced MRI images for prediction of prognosis of lumbar disc herniation, the images of 202 patients were retrospectively compared in relation with their findings at surgery, histo-pathological ones, clinical process and morphology. After intravenous injection of soluble Gd, T1 and T2-weighted imaging had been done with Yokogawa SignaConta (0.5T). Surgery was conducted on 99 patients and conservative therapy, on 103. Patients were classified into 3 groups: those giving enhanced effect in and behind the herniation, and without the effect. The enhancement was observed in 62%. Bad prognosis was seen in 37% of patients without the enhancing effect and the enhanced MRI was concluded to be useful for prediction of prognosis. (K.H.)

  6. Visualizing radiofrequency lesions using delayed-enhancement magnetic resonance imaging in patients with atrial fibrillation: A modification of the method used by the University of Utah group.

    Science.gov (United States)

    Kiuchi, Kunihiko; Okajima, Katsunori; Shimane, Akira; Yokoi, Kiminobu; Teranishi, Jin; Aoki, Kousuke; Chimura, Misato; Tsubata, Hideo; Miyata, Taishi; Matsuoka, Yuuki; Toba, Takayoshi; Ohishi, Shogo; Sawada, Takahiro; Tsukishiro, Yasue; Onishi, Tetsuari; Kobayashi, Seiichi; Yamada, Shinichiro; Taniguchi, Yasuyo; Yasaka, Yoshinori; Kawai, Hiroya; Ikeuchi, Kazushi; Shigenaga, Yutaka; Ikeda, Takayuki

    2015-04-01

    Atrial tissue fibrosis has previously been identified using delayed-enhancement MRI (DE-MRI) in patients with atrial fibrillation (AF). Although the clinical importance of DE-MRI is well recognized, the visualization of atrial fibrosis and radiofrequency (RF) lesions has still not been achieved in Japan, primarily because of the differences in contrast agents, volume-rendering tools, and technical experience. The objective of this study was to visualize RF lesions by using commercially available tools. DE-MRI was performed in 15 patients who had undergone AF ablation (age, 59±4 years, left atrium diameter, 40±2 mm). Specific parameters for MR scanning obtained from previous reports were modified. Of the 15 images, the images of three patients were uninterpretable owing to low image quality. RF lesions could be visualized in 8 (67%) of the 12 patients. In the current study, we successfully demonstrated that RF lesions could be visualized in Japanese patients using DE-MRI, although only commercially available tools were used.

  7. Synchronization and array-enhanced resonances in delayed coupled neuronal network with channel noise

    Science.gov (United States)

    Chen, Jianchun; Ding, Shaojie; Li, Hui; He, Guolong; Zhang, Xuejuan

    2014-09-01

    This paper studies the combined effect of transmission delay and channel fluctuations on population behaviors of an excitatory Erdös-Rényi neuronal network. First, it is found that the network reaches a perfect spatial temporal coherence at a suitable membrane size. Such a coherence resonance is stimulus-free and is array-enhanced. Second, the presence of transmission delay can induce intermittent changes of the population dynamics. Besides, two resonant peaks of the population firing rate are observed as delay changes: one is at τd≈7ms for all membrane areas, which reflects the resonance between the delayed interaction and the intrinsic period of channel kinetics; the other occurs when the transmission delay equals to the mean inter-spike intervals of the population firings in the absence of delay, which reflects the resonance between the delayed interaction and the firing period of the non-delayed system. Third, concerning the impact of network topology and population size, it is found that decreasing the connection probability does not change the range of transmission delay but broadens the range of synaptic coupling that supports population neurons to generate action potentials synchronously and temporally coherently. Furthermore, there exists a critical connection probability that distinguishes the population dynamics into an asynchronous and synchronous state. All the results we obtained are based on networks of size N = 500, which are shown to be robust to further increasing the population size.

  8. Enhanced MRI in patients with Ramsay-Hunt's syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Masahiro; Ushiro, Koichi; Yamashita, Toshio; Kumazawa, Tadami (Kansai Medical Univ., Osaka (Japan). Dept. of Otolaryngology); Katoh, Tsutomu (Kansai Medical Univ., Osaka (Japan). Dept. of Radiology)

    1993-01-01

    Enhanced MRI was performed in 14 patients with Ramsay-Hunt,s syndrome to investigate the pathogenesis of this syndrome. All MRI studies were performed on a 0.5T superconductivity MRI system using a head coil with Gd-DTPA. Enhancement was observed in the areas of the distal internal auditory canal and labyrinthine segment in many patients, and was especially prominent in patients suffering from vertigo, tinnitus, and hearing loss. In some patients it involved not only the facial nerve of the internal auditory canal but also the cochlear nerve and vestibular nerves. Since histological changes of the facial nerve in patients with Ramsay-Hunt's syndrome are assumed to occur in the distal internal auditory canal and labyrinthine segment, which is more proximal than the geniculate ganglion, and the possibility is suggested that inflammation may be spread to the vestibular and cochlear nerve via the internal auditory canal. (14 refs., 2 figs.).

  9. 75 FR 17050 - Enhancing Airline Passenger Protections: Extension of Compliance Date for Posting of Flight Delay...

    Science.gov (United States)

    2010-04-05

    ... Office of the Secretary 14 CFR Part 234 RIN No. 2105-AE00 Enhancing Airline Passenger Protections... date of the provision in its final rule entitled ``Enhancing Airline Passenger Protections'' that requires airlines to publish flight delay information on their Web sites. This extension is in response to...

  10. Contrast enhancement of the facial nerve on MRI: normal or pathological?

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Duverneuil, N. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France); Sola-Martinez, M.T. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France); Miaux, Y. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France); Cognard, C. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France); Weil, A. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France); Mompoint, D. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France); Chiras, J. [Neuroradiologie Charcot, La Salpetriere, 75 - Paris (France)

    1997-03-01

    We prospectively analysed the normal contrast-enhanced MRI features of the facial nerve and determined criteria for pathological contrast enhancement. We studied 31 patients with clinically normal facial nerves with T1-weighted images before and after contrast medium. The intensity, thickness and right-left symmetry of enhancement were assessed in each segment and correlated with MRI features observed in abnormal facial nerves. Enhancement along at least one segment of the facial nerve was seen in 98% of cases, but only within the facial canal: Labyrinthine segment: 78.2%; geniculate ganglion: 96.9%; tympanic: 88.4%; mastoid: 66.6%. Marked (++) to intense (+++) enhancement was seen in the labyrinthine segment in 17.4%, the geniculate ganglion in 36.3%, and the tympanic (25.6%) and mastoid (7.1%) segments, whereas intense enhancement was only seen in the geniculate ganglion (6%) and the tympanic segment (11.6%). A right-left asymmetry was noted in 69% of cases. No correlation was found between enhancement and the thickness of the nerve. No enhancement of the eighth nerve was seen. We suggest three criteria for pathological enhancement: Enhancement outside the facial canal; extension of enhancement to the eighth nerve; and intense enhancement in the labyrinthine and/or mastoid segments. (orig.)

  11. Detection of postoperative residual cholesteatoma with delayed contrast-enhanced MR imaging: initial findings

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Marc T.; Heran, Francoise; Lafitte, Francois; Elmaleh-Berges, Monique; Piekarski, Jean-Daniel [Department of Medical Imaging, Fondation Ophthalmologique Adolphe de Rothschild, 25, rue Manin, 75940 Paris (France); Ayache, Denis [Department of Otorhinolaryngology, Fondation Ophthalmologique Adolphe de Rothschild, 25, rue Manin, 75940 Paris (France); Alberti, Corinne [Department of Biostatistics, Hopital Saint-Louis, 1 Avenue Claude Vellefaux, 75010 Paris (France)

    2003-01-01

    Our objective was to assess the value of delayed contrast-enhanced T1-weighted spin-echo MR imaging in the detection of residual cholesteatoma in patients who have undergone canal wall-up tympanoplasty procedure. The MR imaging was obtained prior to revision surgery in 18 patients with opacity of the post-operative cavity at CT examination 12-18 months after canal wall-up tympanoplasty. In each patient the following was performed: precontrast T1- and T2-weighted images; and early and delayed contrast-enhanced axial and coronal T1-weighted imaging. Early and delayed MR imaging results were separately compared with surgical second-look findings. Sensitivity, specificity, and predictive values were evaluated for early and delayed post-contrast MR imaging, compared with second-look surgery findings. A residual cholesteatoma was correctly identified in 8 of 9 cases with delayed contrast-enhanced T1-weighted MR imaging. Mean sensitivity, specificity, positive predictive value, and interobserver agreement (evaluated by kappa statistics) were, respectively, 85.2, 92.6, 92.6%, and kappa=0.78 for the delayed contrast-enhanced MR imaging technique. The same parameters were, respectively, 96.3, 33.3, 60.6, and 0.30 for the early contrast-enhanced T1-weighted MR images. We conclude that delayed contrast-enhanced T1-weighted MR imaging is reliable for the detection of residual cholesteatomas of the middle ear in patients who have undergone canal wall-up tympanoplasty. (orig.)

  12. Gadolinium-DTPA enhancement of symptomatic nerve roots in MRI of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Tyrrell, P.N.M.; Cassar-Pullicino, V.N.; McCall, I.W. [Department of Diagnostic Imaging, The Institute of Orthopaedics, The Robert Jones and Agnes Hunt Orthopaedic and District Hospital NHS Trust, Oswestry, Shropshire SY10 7AG (United Kingdom)

    1998-02-01

    Disc prolapse presenting with sciatica may be associated with enhancement of the symptomatic nerve root following magnetic resonance imaging (MRI) with intravenous gadolinium (Gd)-DTPA. Previous studies have shown, however, that this does not occur in all cases. The aim of this study was to assess the incidence of nerve root enhancement in patients with sciatica and disc prolapse and to try to identify any specific features that might be associated with the phenomenon. A total of 227 patients presenting with low back pain and/or sciatica underwent a MRI study of the lumbar spine with intravenous contrast enhancement. Nineteen of 81 (23.5 %) patients with disc prolapse demonstrated nerve root enhancement. Nerve root enhancement had a highly significant association with sequestrated disc lesions (13/19, 68 %; P < 0.0005), and was primarily seen in the symptomatic ipsilateral nerve root (16/19, 84 %). The sensitivity of nerve root enhancement associated with disc prolapse was 23.5 % with a specificity of 95.9 %, a positive predictive value of 76 % and a negative predictive value of 69.3 %. Nerve root enhancement may be indicative of the symptomatic level but its poor sensitivity negates the routine use of Gd-DTPA in MRI for sciatica. (orig.) With 4 figs., 1 tab., 37 refs.

  13. Verrucous carcinoma of the foot and enhancement assessment by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Wasserman, Paul L. [Wake Forest University Health Sciences, Department of Radiology, Winston-Salem, NC (United States); Taylor, Richard C. [North Carolina Baptist Medical Center, Department of Pathology, Winston-Salem, NC (United States); Pinillia, Jorge [Wake Forest University Health Sciences, Department of Pathology, Winston-Salem, NC (United States); Wuertzer, Scott D. [North Carolina Baptist Medical Center, Department of Radiology, Winston-Salem, NC (United States)

    2009-04-15

    Verrucous carcinoma (VC), also known as epithelioma cuniculatum, of the foot is an uncommon low-grade squamous cell carcinoma with slow, progressive local invasion with minimal dysplasia and low potential for metastasis. We report on a case of VC and the enhancement pattern associated with it on magnetic resonance (MR) imaging. MR imaging revealed a plantar ulcer with an interesting pattern of enhancement at the base of the mass. The interface between the mass and the normal stroma exhibited a fine-filamentous pattern of enhancement, analogous to teased cotton wool, with impressive correlation to the histological appearance of our specimen. It is our opinion that VC could be included in the differential of a plantar ulcer associated with a mass that exhibits this enhancement pattern. (orig.)

  14. Validity of gradient-echo three-dimensional delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: A histologically controlled study

    Energy Technology Data Exchange (ETDEWEB)

    Zilkens, Christoph, E-mail: christoph.zilkens@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Orthopaedic Surgery, Moorenstraße 5, D-40225 Dusseldorf (Germany); Miese, Falk, E-mail: falk.miese@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstraße 5, D-40225 Dusseldorf (Germany); Herten, Monika, E-mail: Moherten@web.de [Univ Dusseldorf, Medical Faculty, Department of Orthopaedic Surgery, Moorenstraße 5, D-40225 Dusseldorf (Germany); Kurzidem, Sabine, E-mail: sabine.kurzidem@uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Orthopaedic Surgery, Moorenstraße 5, D-40225 Dusseldorf (Germany); Jäger, Marcus [Univ Essen, Medical Faculty, Department of Orthopaedic Surgery, D-45147 Essen (Germany); König, Dietmar, E-mail: Dietmarpierre.koenig@lvr.de [LVR Clinic for Orthopedic Surgery, D-41749 Viersen (Germany); Antoch, Gerald, E-mail: antoch@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstraße 5, D-40225 Dusseldorf (Germany); Krauspe, Rüdiger, E-mail: krauspe@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Orthopaedic Surgery, Moorenstraße 5, D-40225 Dusseldorf (Germany); Bittersohl, Bernd, E-mail: bernd.bittersohl@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Orthopaedic Surgery, Moorenstraße 5, D-40225 Dusseldorf (Germany)

    2013-02-15

    Objective: To validate gradient-echo three-dimensional (3D) delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) by means of histological analyses in the assessment of hip joint cartilage. Materials and methods: Twenty-one femoral head specimens collected from 21 patients (7 males, 14 females, mean age: 60.9 ± 9.6 years; range: 37.6–77.3 years), who underwent total hip replacement for symptomatic hip joint osteoarthritis, underwent MRI and histological assessment. A region of 2 cm{sup 2} at the weight-bearing area was marked with four pins to enable multi-planar MRI reformatting to be matched with histological sections. MRI was performed at 3 T with a 3D double-echo steady-state (DESS) sequence for morphological cartilage assessment and 3D Volumetric Interpolated Breathhold Examination (VIBE) for T1{sub Gd} mapping. Histological sections were evaluated according to the Mankin score system. Total Mankin score, grade of toluidine staining (sensitive for glycosaminoglycan content) and a modified Mankin score classification system with four sub-groups of cartilage damage were correlated with MRI data. Results: Spearman's rho correlation analyses revealed a statistically significant correlation between T1{sub Gd} mapping and histological analyses in all categories including total Mankin score (r = −0.658, p-value ≤ 0.001), toluidine staining (r = −0.802, p-value < 0.001) and modified Mankin score (r = −0.716, p-value < 0.001). The correlation between morphological MRI and histological cartilage assessment was statistically significant but inferior to the biochemical cartilage MRI (r-values ranging from −0.411 to 0.525, p-values < 0.001). Conclusions: Gradient-echo dGEMRIC is reliable while offering the unique features of high image resolution and 3D biochemically sensitive MRI for the assessment of early cartilage degeneration.

  15. Technical Note: Quantitative dynamic contrast-enhanced MRI of a 3-dimensional artificial capillary network.

    Science.gov (United States)

    Gaass, Thomas; Schneider, Moritz Jörg; Dietrich, Olaf; Ingrisch, Michael; Dinkel, Julien

    2017-04-01

    Variability across devices, patients, and time still hinders widespread recognition of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as quantitative biomarker. The purpose of this work was to introduce and characterize a dedicated microchannel phantom as a model for quantitative DCE-MRI measurements. A perfusable, MR-compatible microchannel network was constructed on the basis of sacrificial melt-spun sugar fibers embedded in a block of epoxy resin. Structural analysis was performed on the basis of light microscopy images before DCE-MRI experiments. During dynamic acquisition the capillary network was perfused with a standard contrast agent injection system. Flow-dependency, as well as inter- and intrascanner reproducibility of the computed DCE parameters were evaluated using a 3.0 T whole-body MRI. Semi-quantitative and quantitative flow-related parameters exhibited the expected proportionality to the set flow rate (mean Pearson correlation coefficient: 0.991, P quantitative parameters. All evaluated parameters were well in the range of known in vivo results for the applied flow rates. The constructed phantom enables reproducible, flow-dependent, contrast-enhanced MR measurements with the potential to facilitate standardization and comparability of DCE-MRI examinations. © 2017 American Association of Physicists in Medicine.

  16. [The actions of diffusion weighted imaging (DWI) and dynamic contrast enhanced MRI in differentiating breast tumors].

    Science.gov (United States)

    Luo, Yi; Yu, Jianqun; Chen, Dongdong; Xu, Zhongzi; Zeng, Hanjiang

    2013-12-01

    We studied the actions of diffusion weighted imaging (DWI) and dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) in differentiating breast tumors. From January 2010 to February 2012, we retrospectively analyzed data of 95 cases with breast tumor pathologically confirmed from DWI and DCE-MRI. We compared the ADC value, time-intensity curve (TIC) and DCE-MRI parameters between breast tumors, and calculated the sensitivity and specificity for differentiating breast tumors. The results were as follows: (1) On DWI, mean ADC value of malignant tumor was lower than that of benign tumor (P value of time to peak (Tpeak) and maximal enhancement ratio (SImax) were lower than that of benign tumor (all P < 0.05). As for TIC, type II and III were more frequently seen in malignant tumor than in benign tumor whereas type I was more common in benign tumor than in malignant tumor (all P < 0.05). For differentiating breast malignant tumors from benign neoplasm, DCE-MRI obtained a sensitivity of 89.7% and specificity of 70.3%. (3) For differentiating breast malignant tumors from benign neoplasm, ADC value together with TIC obtained a sensitivity of 79.3% and specificity of 78.4%. Malignant or benign breast tumors could have their own unique characteristics on DWI and DCE-MRI. These characteristics might be helpful for differentiating these tumors.

  17. Early and Delayed Myocardial Enhancement in Myocardial Infarction Using Two-Phase Contrast-Enhanced Multidetector-Row CT

    Science.gov (United States)

    Kim, Young-Whan; Han, Seong-Wook; Seo, Joon-Beom

    2007-01-01

    Objective The purpose of this study was to describe the myocardial enhancement patterns in patients with myocardial infarction using two-phase contrast-enhanced multidetector-row computed tomography (MDCT). Materials and Methods Twenty-three patients with clinically proven myocardial infarction (17 acute myocardial infarction [AMI] and 6 chronic myocardial infarction [CMI]) were examined with two-phase contrast-enhanced ECG-gated MDCT. The presence, location, and patterns of myocardial enhancement on two-phase MDCT images were compared with infarcted myocardial territories determined by using electrocardiogram, echocardiography, thallium-201 single photon emission computed tomography, catheter and MDCT coronary angiography. Results After clinical assessment, the presence of myocardial infarctions were found in 27 territories (19 AMI and 8 CMI) of 23 patients. Early perfusion defects were observed in 30 territories of all 23 patients. Three territories not corresponding to a myocardial infarction were detected in three patients with AMI and were associated with artifacts. Fourteen of perfusion defects were in the left anterior descending artery territory, four in the left circumflex artery territory, and nine in the right coronary artery territory. Delayed enhancement was observed in 25 territories (17 AMI and 8 CMI) of 21 patients. Delayed enhancement patterns were variable. Transmural early perfusion defects (n =12) were closely associated with transmural late enhancement (n = 5) and subendocardial residual defect with subepicardial late enhancement (n = 5). Conclusion Myocardial infarction showed early perfusion defects and variable delayed enhancement patterns on two-phase contrast-enhanced MDCT. Delayed enhancement technique of MDCT could provide additional information of the location and extent of infarcted myocardium, and could be useful to plan appropriate therapeutic strategies in patients with AMI. PMID:17420626

  18. Early and Delayed Myocardial Enhancement in Myocardial Infarction Using Two-Phase Contrast-Enhanced Multidetector-Row CT

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Sung-Min; Kim, Young-Whan; Han, Seong-Wook [University of Keimyung College of Medicine, Dongsan Medical Center, Daegu (Korea, Republic of); Seo, Joon-Beom [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2007-04-15

    The purpose of this study was to describe the myocardial enhancement patterns in patients with myocardial infarction using two-phase contrast enhanced multidetector-row computed tomography (MDCT). Twenty-three patients with clinically proven myocardial infarction (17 acute myocardial infarction [AMI] and 6 chronic myocardial infarction [CMI]) were examined with two-phase contrast-enhanced ECG-gated MDCT. The presence, location, and patterns of myocardial enhancement on two phase MDCT images were compared with infarcted myocardial territories determined by using electrocardiogram, echocardiography, thallium-201 single photon emission computed tomography, catheter and MDCT coronary angiography. After clinical assessment, the presence of myocardial infarctions were found in 27 territories (19 AMI and 8 CMI) of 23 patients. Early perfusion defects were observed in 30 territories of all 23 patients. Three territories not corresponding to a myocardial infarction were detected in three patients with AMI and were associated with artifacts. Fourteen of perfusion defects were in the left anterior descending artery territory, four in the left circumflex artery territory, and nine in the right coronary artery territory. Delayed enhancement was observed in 25 territories (17 AMI and 8 CMI) of 21 patients. Delayed enhancement patterns were variable. Transmural early perfusion defects (n =12) were closely associated with transmural late enhancement (n = 5) and subendocardial residual defect with subepicardial late enhancement (n = 5). Myocardial infarction showed early perfusion defects and variable delayed enhancement patterns on two-phase contrast-enhanced MDCT. Delayed enhancement technique of MDCT could provide additional information of the location and extent of infarcted myocardium, and could be useful to plan appropriate therapeutic strategies in patients with AMI.

  19. Dynamic contrast-enhanced MRI of benign prostatic hyperplasia and prostatic carcinoma: correlation with angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ren, J. [Department of Radiology, Xijing Hospital, Fourth Military Medical University, Xi' an (China); Huan, Y. [Department of Radiology, Xijing Hospital, Fourth Military Medical University, Xi' an (China)], E-mail: huanyi3000@163.com; Wang, H. [Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi' an (China); Chang, Y.-J.; Zhao, H.-T.; Ge, Y.-L.; Liu, Y.; Yang, Y. [Department of Radiology, Xijing Hospital, Fourth Military Medical University, Xi' an (China)

    2008-02-15

    Aim: To investigate the diagnostic and differential diagnostic values of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in prostatic diseases, and to investigate the correlation between the parameters of SI-T curves and angiogenesis. Materials and methods: Twenty-one patients with proven prostatic carcinoma (Pca) and 29 patients with proven benign prostatic hyperplasia (BPH) were examined using DCE MRI. Diagnostic characteristics for differentiation were examined using threshold values for maximum peak time, enhancement degree, and enhancement rate. Then, the signal intensity-time curves (SI-T curves) were analysed, and the correlations between the parameters of SI-T curves and the expression levels of vascular endothelial growth factor (VEGF) and microvascular density (MVD) were investigated. All patients underwent prostatectomy. DCE MRI and histological findings were correlated. Results: Pca showed stronger enhancement with an earlier peak time, higher enhancement, and enhancement rate (p < 0.05). Regarding the type of SI-T curves, in the BPH group six were type A, 10 were type B, and 13 were type C, whereas in the Pca group, 14 were type A, six were type B, and only one was type C (Chi-square test, {chi}{sup 2} = 13.57, P < 0.005). The VEGF and MVD expression levels of Pca were higher than those of BPH. Peak time was negatively correlated with the expression levels of VEGF and MVD, whereas the enhancement degree and enhancement rate showed positive correlations (Pearson correlation, p < 0.05). Conclusion: Based on T2-weighted imaging, DCE MRI curves can help to differentiate benign from malignant prostate tissue. In the present study the type C curve was rarely seen with malignant disease, but these results need confirmation.

  20. The value of resting-state functional MRI in subacute ischemic stroke: comparison with dynamic susceptibility contrast-enhanced perfusion MRI

    Science.gov (United States)

    Ni, Ling; Li, Jingwei; Li, Weiping; Zhou, Fei; Wang, Fangfang; Schwarz, Christopher G.; Liu, Renyuan; Zhao, Hui; Wu, Wenbo; Zhang, Xin; Li, Ming; Yu, Haiping; Zhu, Bin; Villringer, Arno; Zang, Yufeng; Zhang, Bing; Lv, Yating; Xu, Yun

    2017-01-01

    To evaluate the potential clinical value of the time-shift analysis (TSA) approach for resting-state fMRI (rs-fMRI) blood oxygenation level-dependent (BOLD) data in detecting hypoperfusion of subacute stroke patients through comparison with dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI). Forty patients with subacute stroke (3–14 days after neurological symptom onset) underwent MRI examination. Cohort A: 31 patients had MRA, DSC-PWI and BOLD data. Cohort B: 9 patients had BOLD and MRA data. The time delay between the BOLD time course in each voxel and the mean signal of global and contralateral hemisphere was calculated using TSA. Time to peak (TTP) was employed to detect hypoperfusion. Among cohort A, 14 patients who had intracranial large-vessel occlusion/stenosis with sparse collaterals showed hypoperfusion by both of the two approaches, one with abundant collaterals showed neither TTP nor TSA time delay. The remaining 16 patients without obvious MRA lesions showed neither TTP nor TSA time delay. Among cohort B, eight patients showed time delay areas. The TSA approach was a promising alternative to DSC-PWI for detecting hypoperfusion in subacute stroke patients who had obvious MRA lesions with sparse collaterals, those with abundant collaterals would keep intact local perfusion. PMID:28139701

  1. Diagnostic value of dynamic contrast-enhanced MRI for submucosal palatal tumors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Hidenobu, E-mail: hidenobu@md.okayama-u.ac.jp [Department of Oral Diagnosis and Dentomaxillofacial Radiology, Okayama University Hospital, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Yanagi, Yoshinobu, E-mail: ya7@md.okayama-u.ac.jp [Department of Oral Diagnosis and Dentomaxillofacial Radiology, Okayama University Hospital, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Hara, Marina, E-mail: hara-m@cc.okayama-u.ac.jp [Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Katase, Naoki, E-mail: katase-n@cc.okayama-u.ac.jp [Department of Oral Pathology and Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Hisatomi, Miki, E-mail: tomi@md.okayama-u.ac.jp [Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Unetsubo, Teruhisa, E-mail: gmd17107@s.okadai.jp [Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Konouchi, Hironobu, E-mail: kono@md.okayama-u.ac.jp [Department of Oral Diagnosis and Dentomaxillofacial Radiology, Okayama University Hospital, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); Takenobu, Toshihiko, E-mail: takenobu@kcgh.gr.jp [Department of Oral and Maxillofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525 (Japan); and others

    2012-11-15

    Objectives: To evaluate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) for differentiating between benign and malignant tumors in the palate. Materials and methods: 26 patients with submucosal palatal tumors were preoperatively examined using DCE-MRI. Their maximum contrast index (CImax), time of CImax (Tmax), and washout ratios (WR300 and WR600) were determined from contrast index curves. The submucosal palatal tumors were divided into two groups according to their Tmax values: the early enhancement group (Tmax < 300 s) consisted of 9 malignant tumors and 6 benign tumors, while the late enhancement group (Tmax {>=} 300 s) included one malignant tumor and 10 benign tumors. We compared the following DCE-MRI parameters between the benign and malignant tumors: CImax and Tmax in all cases and CImax, Tmax, and the washout ratios in the early enhancement group. In addition, we performed a regression analysis of the relationships between tumor size and DCE-MRI parameters; i.e., CImax, Tmax, and washout ratios, among the malignant salivary gland tumors and pleomorphic adenomas. Results: In all cases and the early enhancement group, significant differences in Tmax were detected between the benign and malignant tumors (P < 0.001 and P < 0.05, respectively), and the optimal Tmax cutoff value for differentiating between them was found to be 165 s. None of the other parameters displayed significant differences between the benign and malignant tumors. Only the WR600 of the pleomorphic adenomas was significantly correlated with tumor size (R{sup 2} = 0.92, P < 0.001). Conclusions: Tmax is a useful parameter for distinguishing between benign and malignant submucosal palatal tumors.

  2. Gadoxetate-enhanced versus diffusion-weighted MRI for fused Ga-68-DOTANOC PET/MRI in patients with neuroendocrine tumours of the upper abdomen

    Energy Technology Data Exchange (ETDEWEB)

    Mayerhoefer, Marius E. [Medical University of Vienna, Department of Radiology, Vienna (Austria); Medical University of Vienna/Vienna General Hospital, PET/CT Center, Departments of Radiology and Nuclear Medicine, Vienna (Austria); Ba-Ssalamah, Ahmed; Weber, Michael; Trattnig, Siegfried; Herneth, Andreas [Medical University of Vienna, Department of Radiology, Vienna (Austria); Mitterhauser, Markus; Eidherr, Harald; Wadsak, Wolfgang [Medical University of Vienna, Department of Nuclear Medicine, Radiochemistry and Biomarker Development Unit, Vienna (Austria); Raderer, Markus [Medical University of Vienna, Department of Internal Medicine I, Division of Oncology, Vienna (Austria); Karanikas, Georgios [Medical University of Vienna, Department of Nuclear Medicine, Vienna (Austria)

    2013-07-15

    To compare fused gadoxetate-enhanced Ga-68-DOTANOC PET/MRI and Ga-68-DOTANOC PET/DWI (diffusion-weighted imaging) for the assessment of abdominal neuroendocrine tumours (NETs). Eighteen patients with suspected or histologically proven NETs of the abdomen were enrolled in this retrospective study. All patients underwent Ga-68-DOTANOC PET/CT for a primary search, staging, or restaging, and received an additional MRI, including dynamic gadoxetate-enhanced T1-weighted sequences and DWI (b-values 50, 300 and 600). Co-registered gadoxetate-enhanced PET/MRI and PET/DWI were separately analysed for NET lesions by a nuclear medicine physician and a radiologist in consensus. Sensitivity and specificity were calculated on a per-region, per-organ and per-patient basis. Eighty-seven out of 684 anatomical regions, and 23 out of 270 organs, were NET-positive in 14 out of 18 patients. Region-based sensitivities and specificities were 97.7 % and 99.7 % for gadoxetate-enhanced PET/MRI and 98.9 % and 99.7 % for PET/DWI. Organ-based sensitivities and specificities were 91.3 % and 99.6 % for gadoxetate-enhanced PET/MRI and 95.7 % and 99.6 % for PET/DWI. Finally, patient-based sensitivities and specificities were 100 % and 100 % for gadoxetate-enhanced PET/MRI and 100 % and 75 % for PET/DWI. Sensitivities and specificities of the two methods did not differ significantly. Gadoxetate-enhanced Ga-68-DOTANOC PET/MRI and Ga-68-DOTANOC PET/DWI are equally useful for the assessment of abdominal NETs. (orig.)

  3. Gadoxetic acid enhanced MRI for differentiation of FNH and HCA: a single centre experience

    Energy Technology Data Exchange (ETDEWEB)

    Grieser, Christian; Steffen, Ingo G.; Perez Fernandez, Carmen Maria; Hamm, Bernd; Denecke, Timm [Klinik fuer Radiologie, Campus Virchow-Klinikum, Charite - Universitaetsmedizin Berlin, Berlin (Germany); Kramme, Incken-Birthe; Blaeker, Hendrik; Kilic, Ergin [Institut fuer Pathologie, Campus Virchow-Klinikum, Charite - Universitaetsmedizin Berlin, Berlin (Germany); Seehofer, Daniel [Klinik fuer Allgemein, Viszeral- und Transplantationschirurgie, Campus Virchow-Klinikum, Charite - Universitaetsmedizin Berlin, Berlin (Germany); Schott, Eckart [Medizinische Klinik m.S. Hepatologie und Gastroenterologie, Campus Virchow-Klinikum, Charite - Universitaetsmedizin Berlin, Berlin (Germany)

    2014-06-15

    Evaluation of enhancement characteristics of histopathologically confirmed focal nodular hyperplasias (FNHs) and hepatocellular adenomas (HCAs) with gadoxetic acid-enhanced MRI. Sixty-eight patients with 115 histopathologically proven lesions (FNHs, n = 44; HCAs, n = 71) examined with gadoxetic acid-enhanced MRI were retrospectively enrolled (standard of reference: surgical resection, n = 53 patients (lesions: FNHs, n = 37; HCAs, n = 53); biopsy, n = 15 (lesions: FNHs, n = 7; HCAs, n = 18)). Two radiologists evaluated all MR images regarding morphological features as well as the vascular and hepatocyte-specific enhancement in consensus. For the hepatobiliary phase, relative enhancement of the lesions and lesion to liver enhancement were significantly lower for HCAs (mean, 48.7 (±48.4) % and 49.4 (±33.9) %) compared to FNHs (159.3 (±92.5) %; and 151.7 (±79) %; accuracy of 89 % and 90 %, respectively; P < 0.001). Visual strong uptake of FNHs vs. hypointensity of HCAs in the hepatobiliary phase resulted in an accuracy of 92 %. This parameter was superior to all other morphological and dynamic vascular criteria alone and in combination (accuracy, 54-85 %). For differentiation of FNHs and HCAs by means of MRI, gadoxetic acid uptake in the hepatobiliary phase was found to be superior to all other criteria alone and in combination. (orig.)

  4. Enhanced MRI of breast cancer smaller than 3 cm

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Yukio; Yoshida, Shouji (Hyogo Medical Center for Adults (Japan)); Narabayashi, Isamu (and others)

    1991-11-01

    Twenty-two patients with breast cancers were studied using magnetic resonance (MR) imaging with a cylindrical surface coil at 1.5 Tesla. All were examined with the FE sequence and Gd-DTPA as a contrast medium. These images were compared with micrographs of the specimens. All cancers were enhanced clearly, and demarcated margins or spiculations of the tumors were seen as clearly on MR images as on micrographs of the specimens. In 12 patients (9 carcinomas, 2 fibroadenomas and 1 benign phyllodes tumor), dynamic studies were performed after the intravenous injection of Gd-DTPA. All nine carcinomas showed enhancement characterized by a sudden increase in signal intensity on the order of 100% or more with the first 2 minutes after injection. Two fibroadenomas were enhanced slowly. Thirteen patients with breast cancers were examined with several sequences (FE, T{sub 1}-weighted SE, T{sub 2}-weighted SE and STIR) with or without Gd-DTPA. The most clearly delineated images of the tumors were those of FE images with Gd-DTPA enhancement. A phantom constituted of various concentrations of Gd-DTPA in 20% albumin solution was measured by signal intensities with T{sub 1}-weighted SE sequence and FE sequence. The ratio of enhancement of the 20% albumin solution relative to the Gd-DTPA concentration was higher with the FE sequence than with the SE sequence. The sensitivity of the FE sequence to Gd-DTPA enhancement was 1.5 times that of the SE sequence under the usual concentration of Gd-DTPA. (author).

  5. Contrast medium-enhanced MRI findings and changes over time in stage I tuberculous meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Oztoprak, I. [Department of Radiology Cumhuriyet University Faculty of Medicine, 58140 Sivas (Turkey)], E-mail: oztoprak@cumhuriyet.edu.tr; Guemues, C.; Oztoprak, B. [Department of Radiology Cumhuriyet University Faculty of Medicine, 58140 Sivas (Turkey); Engin, A. [Department of Infectious Diseases, Cumhuriyet University Faculty of Medicine, Sivas (Turkey)

    2007-12-15

    Aim: To demonstrate the detailed imaging characteristics of early tuberculous meningitis (TBM) and changes over time on standard gadolinium-enhanced, T1-weighted magnetic resonance imaging (MRI) images. Materials and methods: Contrast-enhanced, T1-weighted, spin-echo MRI images of 26 patients with early TBM were evaluated retrospectively. Meningeal enhancement characteristics were categorized according to distribution and pattern as diffuse, focal, linear, nodular, and mixed. Results: We found that 35% of patients had diffuse meningeal enhancement and 65% of cases had focal meningeal enhancement. There was a predilection for focal meningeal enhancement in basal pial areas, the interpeduncular fossa being the most common. In six patients with diffuse meningeal enhancement admitted to hospital relatively early after the onset of symptoms, the type of meningeal enhancement later changed to the focal form. Conclusion: Reactive diffuse meningeal enhancement occurs in the early period of TBM on contrast medium-enhanced T1-weighted MR images, but later becomes limited to basal areas.

  6. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Huang, Xinglu [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Qian, Chunqi [Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Zhu, Lei [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Hida, Naoki [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Niu, Gang, E-mail: niug@mail.nih.gov [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Chen, Xiaoyuan, E-mail: shawn.chen@nih.gov [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer MR contrast agents exert influence on T{sub 1} or T{sub 2} relaxation time of the surrounding tissue. Black-Right-Pointing-Pointer Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. Black-Right-Pointing-Pointer Dual contrast MRI enhances the delineation of tumor borders and small lesions. Black-Right-Pointing-Pointer The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd{sup 3+}. Black-Right-Pointing-Pointer The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T{sub 1}) or transverse (T{sub 2}) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T{sub 2} weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T{sub 2} relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to -4.12 {+-} 0.71. Dual contrast MRI also enhanced the

  7. Delayed Gadolinium-Enhanced Magnetic Resonance Imaging (dGEMRIC) of Hip Joint Cartilage: Better Cartilage Delineation after Intra-Articular than Intravenous Gadolinium Injection

    Energy Technology Data Exchange (ETDEWEB)

    Boesen, M.; Jensen, K. E.; Qvistgaard, E.; Danneskiold-Samsoe, B.; Thomsen, C.; Oestergaard, M.; Bliddal, H. [Frederiksberg Hospital, Copenhagen (Denmark). Parker Inst.

    2006-07-15

    Purpose: To investigate and compare delayed gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in the hip joint using intravenous (i.v.) or ultrasound-guided intra-articular (i.a.) Gd-DTPA injection. Material and Methods: In 10 patients (50% males, mean age 58 years) with clinical and radiographic hip osteoarthritis (OA; Kellgren score II-III), MRI of the hip was performed twice on a clinical 1.5T MR scanner: On day 1, before and 90-180 min after 0.3 mmol/kg body weight i.v. Gd-DTPA and, on day 8, 90-180 min after ultrasound-guided i.a. injection of a 4 mmol/l Gd-DTPA solution. Coronal STIR, coronal T1 fat-saturated spin-echo, and a cartilage-sensitive gradient-echo sequence (3D T1 SPGR) in the sagittal plane were applied. Results: Both the post-i.v. and post-i.a. Gd-DTPA images showed significantly higher signal-to-noise (SNR) and contrast-to-noise (CNR) in the joint cartilage compared to the non-enhanced images ( P <0.002). I.a. Gd-DTPA provided significantly higher SNR and CNR compared to i.v. Gd-DTPA ( P <0.01). Furthermore, a better delineation of the cartilage in the synovial/cartilage zone and of the chondral/subchondral border was observed. Conclusion: The dGEMRIC MRI method markedly improved delineation of hip joint cartilage compared to non-enhanced MRI. The i.a. Gd-DTPA provided the best cartilage delineation. dGEMRIC is a clinically applicable MRI method that may improve identification of early subtle cartilage damage and the accuracy of volume measurements of hip joint cartilage.

  8. Soft-Tissue Tumor Contrast Enhancement Patterns: Diagnostic Value and Comparison Between Ultrasound and MRI.

    Science.gov (United States)

    Gruber, Leonhard; Loizides, Alexander; Luger, Anna K; Glodny, Bernhard; Moser, Patrizia; Henninger, Benjamin; Gruber, Hannes

    2017-02-01

    The purpose of this study was to assess and compare contrast-enhanced ultrasound and MRI patterns in the diagnosis of soft-tissue masses. Two hundred fifty-five consecutively registered patients with histologically confirmed soft-tissue masses were included in this retrospective study. The diagnostic properties of four predefined contrast enhancement (CE) patterns were assessed, and logistic regression analysis was performed to determine the correlation between diagnosis and CE pattern, lesion size, and patient age and sex. The influence of lesion size on the occurrence of inhomogeneous CE patterns in malignancies was also determined. Homogeneous CE patterns were highly specific for benignity, and inhomogeneous CE was moderately specific for malignancy in both ultrasound and MRI. A combination of homogeneous and inhomogeneous CE patterns led to 88.3% and 88.7% sensitivity, 66.7% and 59.7% specificity, 73.4% and 68.2% correct classification, 54.6% and 47.8% positive predictive value, 92.6% and 92.7% negative predictive value, 2.65 and 2.20 positive likelihood ratio, and 0.18 and 0.19 negative likelihood ratio for contrast-enhanced ultrasound and contrast-enhanced MRI. Cases with homogeneous CE in either ultrasound or MRI also were predominantly benign. The occurrence of inhomogeneous CE in malignant lesions increased with size. CE patterns in ultrasound and MRI offer additional information about the differentiation of an unknown soft-tissue mass. The results of this study showed that homogeneous or absent CE was specific for benign differentiation and that heterogeneous CE was linked to malignancy. The routine analysis of CE patterns should increase diagnostic reliability in unclear soft-tissue masses.

  9. Diffuse pachymeningeal enhancement on brain MRI: spontaneous intracranial hypotension and head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Chang Woo; Lee, Byung Hee; Lee, Seung Ik; Kim, Young A; Kim, Hee Jin; Ko, Young Sik [Pochon CHA Univ. College of Medicine, Sungnam (Korea, Republic of)

    1998-11-01

    We evaluated the MRI finding of pachymeningeal enhancement in patients with intracranial hypotension and head trauma with particular attention to differential findings and change in follow-up study, and in order to support the knowledge about the pathophysiology of dural enhancement. The findings of enhanced brain MRI of fifteen patients who showed diffuse pachymeningeal enhancement were retrospectively examined. Seven of fifteen patients were finally diagnosed as spontaneous intracranial hypotension (SIH). Eight of fifteen patients had a recent history of head trauma. We analyzed the shape, thickness, continuity and extent of dural enhancement, and the others concerned with positive MR findings. We also analyzed findings suggested displacement of brain parenchyma-displacement of the iter and cerebellar tonsil, and flattening of the anterior aspect of the pons-. Four of seven patients with SIH and four of eight patients with head trauma, underwent follow-up MRI. In the follow-up study, the presence of resolving pachymeningeal enhancement and symptom improvement was investigated. In all cases of SIH, the dura showed diffuse, even 31mm thick, global and contiguous enhancement along both cerebral convexities, both tentoria, and the falx. Displacement of the iter was noted in six cases and flattening of the anterior aspect of the pons in five. Displacement of the cerebellar tonsil was noted in one case. Five of seven cases showed small amount of subdural fluid collection. In all cases of head trauma, the dura was enhanced diffusely and asymmetrically, and showed no contiguity. Its distribution was consistent with the locations of traumatic lesions. Displacement of the iter was noted in one case. In four cases of SIH, clinical symptoms had improved, and three showed complete resolution of dural enhancement, in one patient continuously showed partial dural enhancement. Four cases of head trauma showed complete resolution of dural enhancement. Reversible diffuse

  10. Contrast-enhanced MRI of the small bowel in Crohn's disease.

    Science.gov (United States)

    Oommen, Jacob; Oto, Aytekin

    2011-04-01

    Recently, magnetic resonance imaging has emerged as a valuable tool in evaluation of small bowel Crohn's disease. MRI provides several advantages to other imaging modalities, including the lack of ionizing radiation, multiplanar capability, and functional information. Intravenous contrast administration is a routine portion of MR enterography protocol, and aids in detection of disease extent, extramural complications such as fistula and abscess, and assessment of activity. Additionally, promising techniques such as dynamic contrast-enhanced MRI may provide quantitative measures to assess bowel perfusion, which may enhance evaluation of disease activity. This article will provide an overview of the technical aspects of contrast-enhanced MR enterography, describe common pathologic findings involving the small bowel in Crohn's disease, summarize its role in determination of activity with an emphasis on endoscopic and histologic correlation, and compare its efficacy with other imaging modalities.

  11. [Non-masslike enhancement on breast MRI: interpretation pearls].

    Science.gov (United States)

    Thomassin-Naggara, I; Salem, C; Darai, E; Bazot, M; Uzan, S; Marsault, C; Chopier, J

    2009-03-01

    The MR Breast Imaging Reporting and Data System (BI-RADS) lexicon of the American College of Radiology (ACR) includes a new lesion category defined as non-masslike enhancement. The purpose of this paper is to review the definition of this new entity, illustrate the main imaging features described in the BI-RADS lexicon and to propose a diagnostic approach based on data from the literature in order to achieve diagnosis and optimal patient management.

  12. Manganese-enhanced MRI predicts the histological grade of hepatocellular carcinoma in potential surgical candidates

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, R.P. [Institute of Liver Studies, King' s College Hospital, London (United Kingdom); Lewis, D.; Kane, P.A. [Department of Radiology, King' s College Hospital, London (United Kingdom); Portmann, B.C.; O' Grady, J.G. [Institute of Liver Studies, King' s College Hospital, London (United Kingdom); Karani, J.B. [Department of Radiology, King' s College Hospital, London (United Kingdom); Rela, M. [Institute of Liver Studies, King' s College Hospital, London (United Kingdom); Heaton, N.D., E-mail: Nigel.Heaton@kch.nhs.u [Institute of Liver Studies, King' s College Hospital, London (United Kingdom)

    2011-03-15

    Aim: To evaluate the role of manganese-enhanced magnetic resonance (Mn-MRI) in predicting tumour differentiation prior to liver transplant or resection for hepatocellular carcinoma (HCC). Materials and methods: The inclusion criteria were patients with HCC who underwent Mn-MRI prior to transplantation or resection from 2001-2008. T1-weighted MRI images were acquired at 0 and 24 h after manganese dipyridoxal diphosphate (MnDPDP) intravenous contrast medium and reviewed prospectively. Manganese retention at 24 h was correlated with tumour differentiation and disease-free survival. Results: Eighty-six patients underwent Mn-MRI (transplantation 60, resection 26); 114/125 lesions (91%) that were arterialised as evidenced at computed tomography (CT) and had manganese uptake on MRI were HCC. There were 11 false positives (9%) that were regenerative nodules. Ten of fourteen non-manganese-retaining HCC (71%) were poorly differentiated, compared with only 13/114 manganese-retaining HCC (11%) (p < 0.0001). Sensitivity, specificity, positive and negative predictive values of non-retention of MnDPDP in predicting poorly differentiated tumours were 0.43, 0.96, 0.71 and 0.88. Median disease-free survival of patients with non-manganese-retaining HCC was less than for patients with manganese-retaining HCC (14 {+-} 5 months versus 39 {+-} 3 months, log rank p = 0.025). Conclusion: Non-manganese-retaining HCCs are likely to be poorly differentiated and have a poor prognosis. Manganese-enhanced MRI appears to have a role in preoperative assessment of HCC and warrants further evaluation.

  13. Accuracy of enhanced and unenhanced MRI in diagnosing scaphoid proximal pole avascular necrosis and predicting surgical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Fox, M.G. [University of Virginia, Department of Radiology and Medical Imaging, Charlottesville, VA (United States); Wang, D.T. [University of Virginia, Department of Radiology and Medical Imaging, Charlottesville, VA (United States); Medical College of Wisconsin, Milwaukee, WI (United States); Chhabra, A.B. [University of Virginia Health System, Department of Orthopedics, Charlottesville, VA (United States)

    2015-11-15

    Determine the sensitivity, specificity and accuracy of unenhanced and enhanced MRI in diagnosing scaphoid proximal pole (PP) avascular necrosis (AVN) and correlate whether MRI can help guide the selection of a vascularized or nonvascularized bone graft. The study was approved by the IRB. Two MSK radiologists independently performed a retrospective review of unenhanced and enhanced MRIs from 18 patients (16 males, 2 females; median age, 17.5 years) with scaphoid nonunions and surgery performed within 65 days of the MRI. AVN was diagnosed on the unenhanced MRI when a diffusely decreased T1-W signal was present in the PP and on the enhanced MRI when PP enhancement was less than distal pole enhancement. Surgical absence of PP bleeding was diagnostic of PP AVN. Postoperative osseous union (OU) was assessed with computed tomography and/or radiographs. Sensitivity, specificity and accuracy for PP AVN were 71, 82 and 78 % for unenhanced and 43, 82 and 67 % for enhanced MRI. Patients with PP AVN on unenhanced MRI had 86 % (6/7) OU; 100 % (5/5) OU with vascularized bone grafts and 50 % (1/2) OU with nonvascularized grafts. Patients with PP AVN on enhanced MRI had 80 % (4/5) OU; 100 % (3/3) OU with vascularized bone grafts and 50 % (1/2) OU with nonvascularized grafts. Patients with viable PP on unenhanced and enhanced MRI had 91 % (10/11) and 92 % (12/13) OU, respectively, all but one with nonvascularized graft. When PP AVN is evident on MRI, OU is best achieved with vascularized grafts. If PP AVN is absent, OU is successful with nonvascularized grafts. (orig.)

  14. The diagnostic role of gadolinium enhanced MRI in distinguishing between acute medullary bone infarct and osteomyelitis.

    Science.gov (United States)

    Umans, H; Haramati, N; Flusser, G

    2000-04-01

    The objective of the study was to evaluate the diagnostic utility of contrast enhanced magnetic resonance imaging (MRI) for distinguishing between acute medullary bone infarct and osteomyelitis. There were 11 patients (age 6-34 years) presented to our institution between December 1994 and February 1998 with a clinical differential diagnosis of acute bone infarct versus osteomyelitis and inconclusive radiographs were imaged using MRI. All but one received i.v. gadolinium. Nine of the patients had homozygous Sickle Cell disease (SCD) and two had Systemic Lupus Erythematosus (SLE), the latter requiring chronic methylprednisolone. Osteomyelitis was confirmed either by biopsy alone or by the combination of Gallium(67) scan in conjunction with positive blood cultures and clinical resolution following antibiotics. Infarcts without osteomyelitis were confirmed either by biopsy or resolution of symptoms without antibiotic therapy. All patients had at least six months clinical follow-up. The results found that seven of nine patients with SCD had acute infarct only. One patient with SCD had osteomyelitis only. Three patients (two SLE and one SCD) had both acute-on-chronic infarcts and superimposed osteomyelitis, one with an adjacent soft tissue abscess. Accurate distinction between infarct and osteomyelitis was impossible for one patient with SLE who did not receive contrast. All other cases were correctly diagnosed prospectively based on distinct patterns of MRI contrast enhancement. In all adult patients, acute infarcts demonstrated thin, linear rim enhancement on MRI while osteomyelitis revealed more geographic and irregular marrow enhancement. Two of four cases of osteomyelitis also demonstrated subtle cortical defects with abnormal signal traversing marrow and soft tissue. The single pediatric patient demonstrated elongated, serpiginous central medullary enhancement with periostitis. We concluded that the pattern of MR contrast enhancement may allow accurate distinction

  15. Comparison of detection pattern of HCC by ferumoxide-enhanced MRI and intratumoral blood flow pattern

    Energy Technology Data Exchange (ETDEWEB)

    Itou, Naoki; Kotake, Fumio [Tokyo Medical Coll., Ami, Ibaraki (Japan). Kasumigaura Hospital; Saitou, Kazuhiro; Abe, Kimihiko

    2000-08-01

    We compared the detection rate and pattern of ferumoxide-enhanced magnetic resonance imaging (Fe-MRI) with the intratumoral blood flow pattern determined by CT angiography (CTA) and CT portography (CTAP) in 124 nodes (34 cases) diagnosed as hepatocellular carcinoma (HCC) or borderline HCC, based on the clinical course. Sequences to obtain a T1-weighted images (T1W), proton density-weighted images (PDW), T2-weighted images (T2W), T2*-weighted images (T2*W) were used in Fe-MRI. In nodes shown to be hypervascular on CTA, the detection rate by Fe-MRI was 69.7%. In nodes shown to be avascular by CTAP, the detection rate by Fe-MRI was 67.3%. These rates were higher than with other flow patterns. In nodes showing high signal intensity (HSI) on any sequences, arterial blood flow was increased and portal blood flow decreased in comparison with nodes without high signal intensity. All nodes showing HSI, both on Fe-MRI T2W and T2*W, were hypervascular on CTA, and portal blood flow was absent on CTAP. Nodes showing HSI on both T2*W and T2W were considered to have greater arterial blood flow and decreased portal blood flow compared with nodes appearing as HSI on T2*W, but only as iso- or low signal intensity on T2W (Mann-Whitney U-test; p<0.05). (author)

  16. Efficient compressed sensing SENSE parallel MRI reconstruction with joint sparsity promotion and mutual incoherence enhancement.

    Science.gov (United States)

    Il Yong Chun; Adcock, Ben; Talavage, Thomas M

    2014-01-01

    Magnetic resonance imaging (MRI) is considered a key modality for the future as it offers several advantages, including the use of non-ionizing radiation and having no known side effects on the human body, and has recently begun to serve as a key component of multi-modal neuroimaging. However, two major intrinsic problems exist: slow acquisition and intrusive acoustic noise. Parallel MRI (pMRI) techniques accelerate acquisition by reducing the duration and coverage of conventional gradient encoding. The under-sampled k-space data is detected with several receiver coils surrounding the object, using distinct spatial encoding information for each coil element to reconstruct the image. However, this scanning remains slow compared to typical clinical imaging (e.g. X-ray CT). Compressed Sensing (CS), a sampling theory based on random sub-sampling, has potential to further reduce the sampling used in pMRI, accelerating acquisition further. In this work, we propose a new CS SENSE pMRI reconstruction model promoting joint sparsity across channels and enhancing mutual incoherence to improve reconstruction accuracy from limited k-space data. For fast image reconstruction and fair comparisons, all reconstructions are computed with split-Bregman and variable splitting techniques. Numerical results show that, with the introduced methods, reconstruction performance can be crucially improved with limited amount of k-space data.

  17. Impact of menopausal status on background parenchymal enhancement and fibroglandular tissue on breast MRI

    Energy Technology Data Exchange (ETDEWEB)

    King, Valencia [Memorial Sloan-Kettering Cancer Center, Department of Radiology, Breast Imaging Section, New York, NY (United States); Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York, NY (United States); Gu, Yajia [Fudan University Shanghai Cancer Center, Department of Radiology, Shanghai (China); Fudan University, Department of Oncology, Shanghai Medical College, Shanghai (China); Kaplan, Jennifer B.; Morris, Elizabeth A. [Memorial Sloan-Kettering Cancer Center, Department of Radiology, Breast Imaging Section, New York, NY (United States); Brooks, Jennifer D.; Pike, Malcolm C. [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States)

    2012-12-15

    To evaluate the effect of menopausal status on the background parenchymal enhancement (BPE) and amount of fibroglandular tissue (FGT) on breast MRI. Retrospective review identified 1,130 women who underwent screening breast MRI between July and November 2010. In 28 of these women, breast MRI was performed both at one time point while pre- and one time point while post-menopausal (median interval 49 months). Two independent readers blinded to menopausal status used categorical scales to rate BPE (minimal/mild/moderate/marked) and FGT (fatty/scattered/heterogeneously dense/dense). Consensus was reached when there was disagreement. The sign test was used to assess changes in rating categories, and the Spearman rank and Fisher's exact tests were used to measure correlations and associations between variables. Significant proportions of women demonstrated decreases in BPE and FGT on post-menopausal breast MRI (P = 0.0001 and P = 0.0009). BPE category was unchanged in 39 % (11/28) and decreased in 61 % (17/28) of women. FGT category was unchanged in 61 % (17/28) and decreased in 39 % (11/28) of women. Age, reason for menopause, or interval between MRIs had no significant impact on changes in BPE and FGT. On MRI, BPE, and FGT decrease after menopause in significant proportions of women; BPE decreases more than FGT. (orig.)

  18. Prospective comparison of T2w-MRI and dynamic-contrast-enhanced MRI, 3D-MR spectroscopic imaging or diffusion-weighted MRI in repeat TRUS-guided biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Portalez, Daniel [Clinique Pasteur, 45, Department of Radiology, Toulouse (France); Rollin, Gautier; Mouly, Patrick; Jonca, Frederic; Malavaud, Bernard [Hopital de Rangueil, Department of Urology, Toulouse Cedex 9 (France); Leandri, Pierre [Clinique Saint Jean, 20, Department of Urology, Toulouse (France); Elman, Benjamin [Clinique Pasteur, 45, Department of Urology, Toulouse (France)

    2010-12-15

    To compare T2-weighted MRI and functional MRI techniques in guiding repeat prostate biopsies. Sixty-eight patients with a history of negative biopsies, negative digital rectal examination and elevated PSA were imaged before repeat biopsies. Dichotomous criteria were used with visual validation of T2-weighted MRI, dynamic contrast-enhanced MRI and literature-derived cut-offs for 3D-spectroscopy MRI (choline-creatine-to-citrate ratio >0.86) and diffusion-weighted imaging (ADC x 10{sup 3} mm{sup 2}/s < 1.24). For each segment and MRI technique, results were rendered as being suspicious/non-suspicious for malignancy. Sextant biopsies, transition zone biopsies and at least two additional biopsies of suspicious areas were taken. In the peripheral zones, 105/408 segments and in the transition zones 19/136 segments were suspicious according to at least one MRI technique. A total of 28/68 (41.2%) patients were found to have cancer. Diffusion-weighted imaging exhibited the highest positive predictive value (0.52) compared with T2-weighted MRI (0.29), dynamic contrast-enhanced MRI (0.33) and 3D-spectroscopy MRI (0.25). Logistic regression showed the probability of cancer in a segment increasing 12-fold when T2-weighted and diffusion-weighted imaging MRI were both suspicious (63.4%) compared with both being non-suspicious (5.2%). The proposed system of analysis and reporting could prove clinically relevant in the decision whether to repeat targeted biopsies. (orig.)

  19. Dynamic Contrast-Enhanced MRI of Cervical Cancers: Temporal Percentile Screening of Contrast Enhancement Identifies Parameters for Prediction of Chemoradioresistance

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Erlend K.F. [Department of Medical Physics, Oslo University Hospital, Oslo (Norway); Hole, Knut Hakon; Lund, Kjersti V. [Department of Radiology, Oslo University Hospital, Oslo (Norway); Sundfor, Kolbein [Department of Gynaecological Oncology, Oslo University Hospital, Oslo (Norway); Kristensen, Gunnar B. [Department of Gynaecological Oncology, Oslo University Hospital, Oslo (Norway); Institute for Medical Informatics, Oslo University Hospital, Oslo (Norway); Lyng, Heidi [Department of Radiation Biology, Oslo University Hospital, Oslo (Norway); Malinen, Eirik, E-mail: eirik.malinen@fys.uio.no [Department of Medical Physics, Oslo University Hospital, Oslo (Norway); Department of Physics, University of Oslo, Oslo (Norway)

    2012-03-01

    Purpose: To systematically screen the tumor contrast enhancement of locally advanced cervical cancers to assess the prognostic value of two descriptive parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods and Materials: This study included a prospectively collected cohort of 81 patients who underwent DCE-MRI with gadopentetate dimeglumine before chemoradiotherapy. The following descriptive DCE-MRI parameters were extracted voxel by voxel and presented as histograms for each time point in the dynamic series: normalized relative signal increase (nRSI) and normalized area under the curve (nAUC). The first to 100th percentiles of the histograms were included in a log-rank survival test, resulting in p value and relative risk maps of all percentile-time intervals for each DCE-MRI parameter. The maps were used to evaluate the robustness of the individual percentile-time pairs and to construct prognostic parameters. Clinical endpoints were locoregional control and progression-free survival. The study was approved by the institutional ethics committee. Results: The p value maps of nRSI and nAUC showed a large continuous region of percentile-time pairs that were significantly associated with locoregional control (p < 0.05). These parameters had prognostic impact independent of tumor stage, volume, and lymph node status on multivariate analysis. Only a small percentile-time interval of nRSI was associated with progression-free survival. Conclusions: The percentile-time screening identified DCE-MRI parameters that predict long-term locoregional control after chemoradiotherapy of cervical cancer.

  20. Manganese-enhanced MRI of rat brain based on slow cerebral delivery of manganese(II) with silica-encapsulated Mn x Fe(1-x) O nanoparticles.

    Science.gov (United States)

    Chen, Wei; Lu, Fang; Chen, Chiao-Chi V; Mo, Kuan-Chi; Hung, Yann; Guo, Zhi-Xuan; Lin, Chia-Hui; Lin, Ming-Huang; Lin, Yu-Hsuan; Chang, Chen; Mou, Chung-Yuan

    2013-09-01

    In this work, we report a monodisperse bifunctional nanoparticle system, MIO@SiO2 -RITC, as an MRI contrast agent [core, manganese iron oxide (MIO); shell, amorphous silica conjugated with rhodamine B isothiocyanate (RITC)]. It was prepared by thermal decomposition and modified microemulsion methods. The nanoparticles with varying iron to manganese ratios displayed different saturated magnetizations and relaxivities. In vivo MRI of rats injected intravenously with MIO@SiO2-RITC nanoparticles exhibited enhancement of the T1 contrast in brain tissue, in particular a time-delayed enhancement in the hippocampus, pituitary gland, striatum and cerebellum. This is attributable to the gradual degradation of MIO@SiO2-RITC nanoparticles in the liver, resulting in the slow release of manganese(II) [Mn(II)] into the blood pool and, subsequently, accumulation in the brain tissue. Thus, T1-weighted contrast enhancement was clearly detected in the anatomic structure of the brain as time progressed. In addition, T2*-weighted images of the liver showed a gradual darkening effect. Here, we demonstrate the concept of the slow release of Mn(II) for neuroimaging. This new nanoparticle-based manganese contrast agent allows one simple intravenous injection (rather than multiple infusions) of Mn(II) precursor, and results in delineation of the detailed anatomic neuroarchitecture in MRI; hence, this provides the advantage of the long-term study of neural function. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Immobilized contrast-enhanced MRI: Gadolinium-based long-term MR contrast enhancement of the vein graft vessel wall.

    Science.gov (United States)

    Mitsouras, Dimitris; Vemula, Praveen Kumar; Yu, Peng; Tao, Ming; Nguyen, Binh T; Campagna, Christina M; Karp, Jeffrey M; Mulkern, Robert V; Ozaki, C Keith; Rybicki, Frank J

    2011-01-01

    An implantable MR contrast agent that can be covalently immobilized on tissue during surgery has been developed. The rationale is that a durable increase in tissue contrast using an implantable contrast agent can enhance postsurgical tissue differentiation using MRI. For small-vessel (e.g., vein graft) MRI, the direct benefit of such permanent "labeling" of the vessel wall by modification of its relaxation properties is to achieve more efficient imaging. This efficiency can be realized as either increased contrast leading to more accurate delineation of vessel wall and lesion tissue boundaries, or, faster imaging without penalizing contrast-to-noise ratio, or a combination thereof. We demonstrate, for the first time, stable long-term MRI enhancement using such an exogenous contrast mechanism based on immobilizing a modified diethylenetriaminepentaacetic acid gadolinium(3+) dihydrogen complex on a human vein using a covalent amide bond. Signal enhancement due to the covalently immobilized contrast agent is demonstrated for excised human vein specimens imaged at 3 T, and its long-term stability is demonstrated during a 4-month incubation period.

  2. Noninvasive detection of cardiac amyloidosis using delayed enhanced MDCT: a pilot study.

    Science.gov (United States)

    Deux, Jean-François; Mihalache, Cristian-Ionut; Legou, François; Damy, Thibaud; Mayer, Julie; Rappeneau, Stéphane; Planté-Bordeneuve, Violaine; Luciani, Alain; Kobeiter, Hicham; Rahmouni, Alain

    2015-08-01

    To evaluate myocardial enhancement of patients with cardiac amyloidosis (CA) using computed tomography (CT). Thirteen patients with CA and 11 control patients were examined with first-pass and delayed CT acquisition. A qualitative and quantitative analysis of images was performed. Myocardial attenuation, myocardial signal-to-noise ratio (SNRmyoc), blood pool SNR (SNRblood), contrast-to-noise ratio between blood pool and myocardium (CNRblood-myoc) and relative attenuation index (RAI) defined as variation of myocardial attenuation between delayed and first-pass acquisitions were calculated. Two false negative cases (15 %) and three false positive cases (27 %) were detected on qualitative analysis. SNRmyoc of patients with CA was significantly (p < 0.05) lower on first-pass (4.08 ± 1.9) and higher on delayed acquisition (7.10 ± 2.7) than control patients (6.1 ± 2.2 and 5.03 ± 1.8, respectively). Myocardial attenuation was higher in CA (121 ± 39 HU) than control patients (81 ± 17 HU) on delayed acquisition. CNRblood-myoc was significantly (p < 0.05) lower in CA (1.51 ± 0.7) than control patients (2.85 ± 1.2) on delayed acquisition. The RAI was significantly (p < 0.05) higher in CA (0.12 ± 0.25) than in control patients (-0.56 ± 0.21). Dual phase MDCT can detect abnormal myocardial enhancement in patients with CA. • CT can detect abnormal first-pass and delayed enhancement in cardiac amyloidosis. • Measurement of relative myocardial enhancement between acquisitions helps to detect cardiac amyloidosis. • CT may provide useful data to diagnose cardiac amyloidosis.

  3. Transudative vs exudative pleural effusions: differentiation using Gd-DTPA-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Frola, C. [IV Divisione Radiologica, Ospedale S. Martino, V. le Benedetto XV, 10, I-16132 Genova (Italy); Cantoni, S. [IV Divisione Radiologica, Ospedale S. Martino, V. le Benedetto XV, 10, I-16132 Genova (Italy); Turtulici, I. [IV Divisione Radiologica, Ospedale S. Martino, V. le Benedetto XV, 10, I-16132 Genova (Italy); Leoni, C. [Divisione di Chirurgia Toracica, Ospedale S. Martino, V. le Benedetto XV, 10, I-16132 Genova (Italy); Loria, F. [IV Divisione Radiologica, Ospedale S. Martino, V. le Benedetto XV, 10, I-16132 Genova (Italy); Gaeta, M. [Servizio di Radiologia, Ospedale Piemonte, I-98100 Messina (Italy); Derchi, L.E. [Cattedra di Radiologia, Universita degli Studi, V. le Benedetto XV, 10, I-16132 Genova (Italy)

    1997-08-01

    The aim of this study was to investigate the capability of Gd-DTPA-enhanced MRI to differentiate between exudative and transudative pleural effusions. An MRI examination was performed on 22 patients with different types of pleural effusion (10 transudative and 12 exudative effusions). T1-weighted SE images were obtained before and 20 min after administration of Gd-DTPA (0.1 mmol/kg). The degree of enhancement of pleural effusions was evaluated both by visual assessement and by quantitative analysis of images. None of 10 transudative effusions showed significative enhancement, whereas 10 of 12 exudative effusions showed enhancement (sensitivity 83 %, specificity 100 %, positive predictive value 100 %). The postcontrast signal intensity ratios (SIRs) of exudates were significantly higher than corresponding precontrast ratios (P = 0.0109) and the postcontrast SIRs of exudates were significantly higher than those of transudates (P = 0.0300). Exudative pleural effusions show a significant enhancement following administration of Gd-DTPA. We presume that this may be caused by increased pleural permeability and more rapid passage of a large amount of Gd-DTPA from the blood into the pleural fluid in case of exudative effusions. In our limited group of patients, signal enhancement proved the presence of an exudative effusion. Absence of signal enhancement suggests a transudate, but does not exclude an exudate. (orig.). With 5 figs., 2 tabs.

  4. Early Reversible Ischemia of Femoral Head Epiphysis in Piglets on Gadolinium-enhanced MRI: An experimental study

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoming; HU Junwu; ZHEN Hongwei; TANG Lihua; XU Anhui

    2006-01-01

    The purpose of this study is to demonstrate if Gadolinium-enhanced MRI can detect early reversible ischemia of the femoral head epiphysis caused by hip hyper-abduction in piglets. Between 3 and 6 h consistent hyper-abduction, gadolinium-enhanced MRI was performed in 20 femoral heads of 10 piglets. After completion of MRI scan, the piglets were allowed to ambulate freely for 1 or 7 days and re-imaged. The enhanced-MRI results of epiphyseal and physeal cartilage and the secondary center of ossification were observed. MRI appearances and histological findings were compared. On Gadolinium-enhanced MRI, decreased or absent enhancement was seen in 14 cartilaginous epiphyses of all 20 femoral heads. Reperfusion was completed in 10 of 14 femoral heads after one day of ambulation and in the rest 4 after 7 days of ambulation. Gadolinium-enhanced MRI can identify early ischemia and its reversal of the capital femoral epiphysis induced by hip hyper-abduction.

  5. MRI-guided gas bubble enhanced ultrasound heating in in vivo rabbit thigh.

    Science.gov (United States)

    Sokka, S D; King, R; Hynynen, K

    2003-01-21

    In this study, we propose a focused ultrasound surgery protocol that induces and then uses gas bubbles at the focus to enhance the ultrasound absorption and ultimately create larger lesions in vivo. MRI and ultrasound visualization and monitoring methods for this heating method are also investigated. Larger lesions created with a carefully monitored single ultrasound exposure could greatly improve the speed of tumour coagulation with focused ultrasound. All experiments were performed under MRI (clinical, 1.5 T) guidance with one of two eight-sector, spherically curved piezoelectric transducers. The transducer, either a 1.1 or 1.7 MHz array, was driven by a multi-channel RF driving system. The transducer was mounted in an MRI-compatible manual positioning system and the rabbit was situated on top of the system. An ultrasound detector ring was fixed with the therapy transducer to monitor gas bubble activity during treatment. Focused ultrasound surgery exposures were delivered to the thighs of seven New Zealand while rabbits. The experimental, gas-bubble-enhanced heating exposures consisted of a high amplitude 300 acoustic watt, half second pulse followed by a 7 W, 14 W or 21 W continuous wave exposure for 19.5 s. The respective control sonications were 20 s exposures of 14 W, 21 W and 28 W. During the exposures, MR thermometry was obtained from the temperature dependency of the proton resonance frequency shift. MRT2-enhanced imaging was used to evaluate the resulting lesions. Specific metrics were used to evaluate the differences between the gas-bubble-enhanced exposures and their respective control sonications: temperatures with respect to time and space, lesion size and shape, and their agreement with thermal dose predictions. The bubble-enhanced exposures showed a faster temperature rise within the first 4 s and higher overall temperatures than the sonications without bubble formation. The spatial temperature maps and the thermal dose maps derived from the MRI

  6. Dynamic contrast-enhanced MRI for treatment response assessment in patients with oesophageal cancer receiving neoadjuvant chemoradiotherapy

    NARCIS (Netherlands)

    Heethuis, Sophie E.; van Rossum, Peter S N; Lips, IM; Goense, Lucas; Voncken, Francine E.; Reerink, Onne; van Hillegersberg, Richard; Ruurda, Jelle P.; Philippens, Marielle E.; van Vulpen, Marco; Meijer, Gert J.; Lagendijk, JJW; van Lier, A.L.H.M.W.

    2016-01-01

    Purpose To explore and evaluate the potential value of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy (nCRT) in oesophageal cancer. Material and methods Twenty-six patients underwent DCE-MRI before, during (

  7. Assessment of the link between quantitative biexponential diffusion-weighted imaging and contrast-enhanced MRI in the liver

    NARCIS (Netherlands)

    Dijkstra, Hildebrand; Oudkerk, Matthijs; Kappert, Peter; Sijens, Paul E.

    Purpose: To investigate if intravoxel incoherent motion (IVIM) modeled diffusion-weighted imaging (DWI) can be linked to contrast-enhanced (CE-)MRI in liver parenchyma and liver lesions. Methods: Twenty-five patients underwent IVIM-DWI followed by multiphase CE-MRI using Gd-EOB-DTPA (n = 20) or

  8. Gadolinium-enhanced MRI features of acute gouty arthritis on top of chronic gouty involvement in different joints

    NARCIS (Netherlands)

    Emad, Yasser; Ragab, Yasser; El-Naggar, Ahmed; El-Shaarawy, Nashwa; Abd-Allah, Mayada A.; Gamal, Rania M.; Fathy, Ahmed; Hawass, Mona; Rasker, Hans

    2015-01-01

    The aims of the current study are to describe gadolinium-enhanced MRI features of an acute flare of established gouty arthritis in different joints and to examine a possible association between serum uric acid and MRI signs indicative of ongoing inflammation and/or structural joint damage as well as

  9. Assessment of blood–brain barrier disruption using dynamic contrast-enhanced MRI. A systematic review

    Directory of Open Access Journals (Sweden)

    Anna K. Heye

    2014-01-01

    Full Text Available There is increasing recognition of the importance of blood–brain barrier (BBB disruption in aging, dementia, stroke and multiple sclerosis in addition to more commonly-studied pathologies such as tumors. Dynamic contrast-enhanced MRI (DCE-MRI is a method for studying BBB disruption in vivo. We review pathologies studied, scanning protocols and data analysis procedures to determine the range of available methods and their suitability to different pathologies. We systematically review the existing literature up to February 2014, seeking studies that assessed BBB integrity using T1-weighted DCE-MRI techniques in animals and humans in normal or abnormal brain tissues. The literature search provided 70 studies that were eligible for inclusion, involving 417 animals and 1564 human subjects in total. The pathologies most studied are intracranial neoplasms and acute ischemic strokes. There are large variations in the type of DCE-MRI sequence, the imaging protocols and the contrast agents used. Moreover, studies use a variety of different methods for data analysis, mainly based on model-free measurements and on the Patlak and Tofts models. Consequently, estimated KTrans values varied widely. In conclusion, DCE-MRI is shown to provide valuable information in a large variety of applications, ranging from common applications, such as grading of primary brain tumors, to more recent applications, such as assessment of subtle BBB dysfunction in Alzheimer's disease. Further research is required in order to establish consensus-based recommendations for data acquisition and analysis and, hence, improve inter-study comparability and promote wider use of DCE-MRI.

  10. Assessment of blood–brain barrier disruption using dynamic contrast-enhanced MRI. A systematic review

    Science.gov (United States)

    Heye, Anna K.; Culling, Ross D.; Valdés Hernández, Maria del C.; Thrippleton, Michael J.; Wardlaw, Joanna M.

    2014-01-01

    There is increasing recognition of the importance of blood–brain barrier (BBB) disruption in aging, dementia, stroke and multiple sclerosis in addition to more commonly-studied pathologies such as tumors. Dynamic contrast-enhanced MRI (DCE-MRI) is a method for studying BBB disruption in vivo. We review pathologies studied, scanning protocols and data analysis procedures to determine the range of available methods and their suitability to different pathologies. We systematically review the existing literature up to February 2014, seeking studies that assessed BBB integrity using T1-weighted DCE-MRI techniques in animals and humans in normal or abnormal brain tissues. The literature search provided 70 studies that were eligible for inclusion, involving 417 animals and 1564 human subjects in total. The pathologies most studied are intracranial neoplasms and acute ischemic strokes. There are large variations in the type of DCE-MRI sequence, the imaging protocols and the contrast agents used. Moreover, studies use a variety of different methods for data analysis, mainly based on model-free measurements and on the Patlak and Tofts models. Consequently, estimated KTrans values varied widely. In conclusion, DCE-MRI is shown to provide valuable information in a large variety of applications, ranging from common applications, such as grading of primary brain tumors, to more recent applications, such as assessment of subtle BBB dysfunction in Alzheimer's disease. Further research is required in order to establish consensus-based recommendations for data acquisition and analysis and, hence, improve inter-study comparability and promote wider use of DCE-MRI. PMID:25379439

  11. Detection of Vulnerable Atherosclerotic Plaques in Experimental Atherosclerosis with the USPIO-Enhanced MRI.

    Science.gov (United States)

    Qi, Chun-Mei; Du, Lili; Wu, Wei-Heng; Li, Dong-Ye; Hao, Ji; Gong, Lei; Deng, Liangrong; Zhang, Tao; Zhang, Chao; Zhang, Yu

    2015-11-01

    This study's goal was to assess the diagnostic value of the USPIO-(ultra-small superparamagnetic iron oxide) enhanced magnetic resonance imaging (MRI) in detection of vulnerable atherosclerotic plaques in abdominal aorta in experimental atherosclerosis. Thirty New Zealand rabbits were randomly divided into two groups, Group A and Group B. Each group comprised 15 animals which were fed with high cholesterol diet for 8 weeks and then subjected to balloon-induced endothelial injury of the abdominal aorta. After another 8 weeks, animals in Group B received adenovirus carrying p53 gene that was injected through a catheter into the aortic segments rich in plaques. Two weeks later, all rabbits were challenged with the injection of Chinese Russell's viper venom and histamine. Pre-contrast images and USPIO-enhanced MRI images were obtained after pharmacological triggering with injection of USPIO for 5 days. Blood specimens were taken for biochemical and serological tests at 0 and 18 weeks. Abdominal aorta was histologically studied. The levels of serum ICAM-1 and VCAM-1 were quantified by ELISA. Vulnerable plaques appeared as a local hypo-intense signal on the USPIO-enhanced MRI, especially on T2*-weighted sequences. The signal strength of plaques reached the peak at 96 h. Lipid levels were significantly (p < 0.05) higher in both Group A and B compared with the levels before the high cholesterol diet. The ICAM-1 and VCAM-1 levels were significantly (p < 0.05) higher in Group B compared with Group A. The USPIO-enhanced MRI efficiently identifies vulnerable plaques due to accumulation of USPIO within macrophages in abdominal aorta plaques.

  12. Gadolinium Contrast Enhancement Improves Confidence in Diagnosing Recurrent Soft Tissue Sarcoma by MRI.

    Science.gov (United States)

    Chou, Shinn-Huey S; Hippe, Daniel S; Lee, Amie Y; Scherer, Kurt; Porrino, Jack A; Davidson, Darin J; Chew, Felix S; Ha, Alice S

    2017-05-01

    To determine how utilization of postgadolinium magnetic resonance imaging (MRI) influenced reader accuracy and confidence at identifying postoperative soft tissue sarcoma (STS) recurrence among readers with various levels of expertise. This retrospective study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. Postoperative MRI from 26 patients with prior STS resection (13 patients with confirmed recurrence, 13 without recurrence) was reviewed. Four blinded readers of varying expertise (radiology resident, fellow, attending, and orthopedic oncologist) initially evaluated only the precontrast images and rated each MRI for recurrence on a 5-point confidence scale. Assessment was repeated with the addition of contrast-enhanced sequences. Diagnostic accuracy based on confidence ratings was evaluated using the area under the receiver operating characteristic curve (AUC). Changes in confidence ratings were calculated using Wilcoxon signed-rank test. All readers demonstrated good diagnostic accuracy both with and without contrast-enhanced images (AUC >0.98 for each reader). When contrast-enhanced images were made available, the resident recorded improved confidence with both assigning (P = 0.031) and excluding recurrence (P = 0.006); the fellow showed improved confidence only with assigning recurrence (P = 0.015); and the surgeon showed improved confidence in excluding recurrence (P = 0.003). The addition of contrast-enhanced images did not significantly influence the diagnostic confidence of the attending radiologist. Diagnostic accuracy of MRI was excellent in evaluating postoperative STS recurrence, and reader confidence improved depending on expertise when postgadolinium imaging was included in the assessment. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  13. Multifunctional nanoparticle platforms for in vivo MRI enhancement and photodynamic therapy of a rat brain cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kopelman, Raoul [Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor MI 48109 (United States)]. E-mail: kopelman@umich.edu; Lee Koo, Yong-Eun [Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor MI 48109 (United States); Philbert, Martin [Environmental Health Sciences, niversity of Michigan (United States); Moffat, Bradford A. [Department of Radiology, The University of Michigan (United States); Ramachandra Reddy, G. [Molecular Therapeutics, Inc., Ann Arbor, MI 48104 (United States); McConville, Patrick [Molecular Therapeutics, Inc., Ann Arbor, MI 48104 (United States); Hall, Daniel E. [Department of Radiology, University of Michigan (United States); Chenevert, Thomas L. [Department of Radiology, University of Michigan (United States); Bhojani, Mahaveer Swaroop [Department of Radiation Oncology, University of Michigan (United States); Buck, Sarah M. [Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor MI 48109 (United States); Rehemtulla, Alnawaz [Department of Radiation Oncology, University of Michigan (United States); Ross, Brian D. [Department of Radiology, University of Michigan (United States)

    2005-05-15

    A paradigm for brain cancer detection, treatment, and monitoring is established. Multifunctional biomedical nanoparticles (30-60 nm) containing photosensitizer externally deliver reactive oxygen species (ROS) to cancer cells while simultaneously enhancing magnetic resonance imaging (MRI) contrast providing real-time tumor kill measurement. Plasma residence time control and specific cell targeting are achieved. A 5 min treatment in rats halted and even reversed in vivo tumor growth after 3-4 days post-treatment.

  14. Multifunctional nanoparticle platforms for in vivo MRI enhancement and photodynamic therapy of a rat brain cancer

    Science.gov (United States)

    Kopelman, Raoul; Lee Koo, Yong-Eun; Philbert, Martin; Moffat, Bradford A.; Ramachandra Reddy, G.; McConville, Patrick; Hall, Daniel E.; Chenevert, Thomas L.; Bhojani, Mahaveer Swaroop; Buck, Sarah M.; Rehemtulla, Alnawaz; Ross, Brian D.

    2005-05-01

    A paradigm for brain cancer detection, treatment, and monitoring is established. Multifunctional biomedical nanoparticles (30-60 nm) containing photosensitizer externally deliver reactive oxygen species (ROS) to cancer cells while simultaneously enhancing magnetic resonance imaging (MRI) contrast providing real-time tumor kill measurement. Plasma residence time control and specific cell targeting are achieved. A 5 min treatment in rats halted and even reversed in vivo tumor growth after 3-4 days post-treatment.

  15. Stochastic resonance enhancement of small-world neural networks by hybrid synapses and time delay

    Science.gov (United States)

    Yu, Haitao; Guo, Xinmeng; Wang, Jiang

    2017-01-01

    The synergistic effect of hybrid electrical-chemical synapses and information transmission delay on the stochastic response behavior in small-world neuronal networks is investigated. Numerical results show that, the stochastic response behavior can be regulated by moderate noise intensity to track the rhythm of subthreshold pacemaker, indicating the occurrence of stochastic resonance (SR) in the considered neural system. Inheriting the characteristics of two types of synapses-electrical and chemical ones, neural networks with hybrid electrical-chemical synapses are of great improvement in neuron communication. Particularly, chemical synapses are conducive to increase the network detectability by lowering the resonance noise intensity, while the information is better transmitted through the networks via electrical coupling. Moreover, time delay is able to enhance or destroy the periodic stochastic response behavior intermittently. In the time-delayed small-world neuronal networks, the introduction of electrical synapses can significantly improve the signal detection capability by widening the range of optimal noise intensity for the subthreshold signal, and the efficiency of SR is largely amplified in the case of pure chemical couplings. In addition, the stochastic response behavior is also profoundly influenced by the network topology. Increasing the rewiring probability in pure chemically coupled networks can always enhance the effect of SR, which is slightly influenced by information transmission delay. On the other hand, the capacity of information communication is robust to the network topology within the time-delayed neuronal systems including electrical couplings.

  16. Dynamic contrast-enhanced MRI in patients with luminal Crohn's disease

    Energy Technology Data Exchange (ETDEWEB)

    Ziech, M.L.W., E-mail: m.l.ziech@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Lavini, C., E-mail: c.lavini@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Caan, M.W.A., E-mail: m.w.a.caan@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Nio, C.Y., E-mail: C.Y.Nio@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Stokkers, P.C.F., E-mail: p.stokkers@slaz.nl [Academic Medical Center, Department of Gastroenterology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Sint Lucas Andreas Ziekenhuis, Department of Gastroenterology, Jan Tooropstraat 164, 1061 AE, Amsterdam (Netherlands); Bipat, S., E-mail: S.Bipat@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Ponsioen, C.Y., E-mail: c.y.ponsioen@amc.uva.nl [Academic Medical Center, Department of Gastroenterology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Nederveen, A.J., E-mail: a.j.nederveen@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Stoker, J., E-mail: j.stoker@amc.uva.nl [Academic Medical Center, Department of Radiology, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands)

    2012-11-15

    Objectives: To prospectively assess dynamic contrast-enhanced (DCE-)MRI as compared to conventional sequences in patients with luminal Crohn's disease. Methods: Patients with Crohn's disease undergoing MRI and ileocolonoscopy within 1 month had DCE-MRI (3T) during intravenous contrast injection of gadobutrol, single shot fast spin echo sequence and 3D T1-weighted spoiled gradient echo sequence, a dynamic coronal 3D T1-weighted fast spoiled gradient were performed before and after gadobutrol. Maximum enhancement (ME) and initial slope of increase (ISI) were calculated for four colon segments (ascending colon + coecum, transverse colon, descending colon + sigmoid, rectum) and (neo)terminal ileum. C-reactive protein (CRP), Crohn's disease activity index (CDAI), per patient and per segment Crohn's disease endoscopic index of severity (CDEIS) and disease duration were determined. Mean values of the (DCE-)MRI parameters in each segment from each patient were compared between four disease activity groups (normal mucosa, non-ulcerative lesions, mild ulcerative and severe ulcerative disease) with Mann-Whitney test with Bonferroni adjustment. Spearman correlation coefficients were calculated for continuous variables. Results: Thirty-three patients were included (mean age 37 years; 23 females, median CDEIS 4.4). ME and ISI correlated weakly with segmental CDEIS (r = 0.485 and r = 0.206) and ME per patient correlated moderately with CDEIS (r = 0.551). ME was significantly higher in segments with mild (0.378) or severe (0.388) ulcerative disease compared to normal mucosa (0.304) (p < 0.001). No ulcerations were identified at conventional sequences. ME correlated with disease duration in diseased segments (r = 0.492), not with CDAI and CRP. Conclusions: DCE-MRI can be used as a method for detecting Crohn's disease ulcerative lesions.

  17. Dynamic gadolinium-enhanced MRI evaluation of porcine femoral head ischemia and reperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, T. [Clinic for Orthopaedics and Sports Traumatology, Dreifaltigkeits-Krankenhaus GmbH, Aachener Str. 445-449, 50933 Koeln (Germany); Drescher, W. [Department of Orthopaedics, Christian Albrechts University, Kiel (Germany); Becker, C. [Department of Orthopaedics, Heinrich Heine University, Duesseldorf (Germany); Sangill, R.; Stoedkilde-Joergensen, H. [Institute for Magnetic Resonance Imaging Tomography, University of Aarhus, Skejby Hospital, Aarhus (Denmark); Heydthausen, M. [Computing Center, Heinrich Heine University, Duesseldorf (Germany); Hansen, E.S.; Buenger, C. [Spine Section, Department of Orthopaedics, University of Aarhus (Denmark)

    2003-02-01

    To examine the potential of gadolinium (Gd)-enhanced dynamic MRI in the detection of early femoral head ischemia. Furthermore, to apply a three-compartment model to achieve a clinically applicable MR index for femoral head perfusion during the steady state and arterial hip joint tamponade.Design and materials In a porcine model femoral head perfusion was measured by radioactive tracer microspheres and by using a dynamic Gd-enhanced MRI protocol. Femoral head perfusion measurements and MRI tests were performed unilaterally before, during and after the experimentally induced ischemia of one of the hip joints. Ischemia was induced by increasing intra-articular pressure to 250 mmHg. All pigs showed ischemia of the femoral head epiphysis under hip joint tamponade followed by reperfusion to the same level as before joint tamponade. In two cases perfusion after removal of tamponade continued to be low. In dynamic MRI measurements increases in signal intensity were seen after intravenous infusion of Gd-DTPA, followed by a slow decrease in signal intensity. The signal-intensity curve during femoral head ischemia had a minor increase. Also the coefficient determined was a helpful indicator of femoral head ischemia. Femoral head blood flow as measured by microspheres fell significantly under joint tamponade. Early detection of this disturbed regional blood flow was possible using a dynamic MRI procedure. A biomathematical model resulted from the evaluation of the intervals of signal intensity over time which allows detection of bone blood flow changes at a very early stage. Using this new method earlier detection of femoral head necrosis may be possible. (orig.)

  18. Microarray Gene Expression Analysis of Murine Tumor Heterogeneity Defined by Dynamic Contrast-Enhanced MRI

    Directory of Open Access Journals (Sweden)

    Nick G. Costouros

    2002-07-01

    Full Text Available Current methods of studying angiogenesis are limited in their ability to serially evaluate in vivo function throughout a target tissue. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI and pharmacokinetic modeling provide a useful method for evaluating tissue vasculature based on contrast accumulation and washout. While it is often assumed that areas of high contrast enhancement and washout comprise areas of increased angiogenesis and tumor activity, the actual molecular pathways that are active in such areas are poorly understood. Using DCE-MRI in a murine subcutaneous tumor model, we were able to perform pharmacokinetic functional analysis of a tumor, coregistration of MRI images with histological cross-sections, immunohistochemistry, laser capture microdissection, and genetic profiling of tumor heterogeneity based on pharmacokinetic parameters. Using imaging as a template for biologic investigation, we have not found evidence of increased expression of proangiogenic modulators at the transcriptional level in either distinct pharmacokinetic region. Furthermore, these regions show no difference on histology and CD31 immunohistochemistry. However, the expression of ribosomal proteins was greatly increased in high enhancement and washout regions, implying increased protein translation and consequent increased cellular activity. Together, these findings point to the potential importance of posttranscriptional regulation in angiogenesis and the need for the development of angiogenesis-specific contrast agents to evaluate in vivo angiogenesis at a molecular level.

  19. Spinal epidural abscess with gadolinium-enhanced MRI: serial follow-up studies and clinical correlations

    Energy Technology Data Exchange (ETDEWEB)

    Sadato, N. (Dept. of Diagnostic Radiology, Maryland Univ. Medical System, Baltimore, MD (United States)); Numaguchi, Y. (Dept. of Diagnostic Radiology, Maryland Univ. Medical System, Baltimore, MD (United States)); Rigamonti, D. (Dept. of Neurological Surgery, Maryland Univ. Medical System, Baltimore, MD (United States)); Kodama, T. (Dept. of Diagnostic Radiology, Maryland Univ. Medical System, Baltimore, MD (United States)); Nussbaum, E. (Dept. of Neurological Surgery, Maryland Univ. Medical System, Baltimore, MD (United States)); Sato, S. (Dept. of Diagnostic Radiology, Maryland Univ. Medical System, Baltimore, MD (United States)); Rothman, M. (Dept. of Diagnostic Radiology, Maryland Univ. Medical System, Baltimore, MD (United States))

    1994-01-01

    We reviewed serial MRI with and without gadolinium-DTPA in eight patients with spinal epidural abscess and correlated the findings and the clinical manifestations. In four patients, diffuse abscesses spanned four vertebral bodies or more; the others had focal abscesses associated with osteomyelitis and/or diskitis. In three of the four patients with diffuse abscesses, MRI (NCMRI) showed diffuse encasement of the subarachnoid space. Contrast-enhanced MRI (CEMRI) demonstrated linear enhancement surrounding unenhanced pus. In the four patients with focal abscesses, CEMR delineated the inflammatory process more clearly than NCMR. On follow-up studies, decrease in abscess size and better visualization of the subarachnoid space correlated with clinical improvement in both diffuse and focal abscesses. Despite clinical improvement, contrast enhancement persisted in the disk or epidural space of three patients, and was thought to represent chronic granulomatous change or postsurgical scar. CEMR is very valvable for the initial diagnosis of an epidural abscess, particularly if it involves lengthy segments. During follow-up, CEMR can document responses to therapy, and provide information for determining appropriate treatment. (orig.)

  20. Tissue Border Enhancement by inversion recovery MRI at 7.0 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Costagli, Mauro; Tiberi, Gianluigi [Imago7 Foundation, Pisa (Italy); IRCCS Stella Maris, Pisa (Italy); Kelley, Douglas A.C. [GE Healthcare Technologies, San Francisco, CA (United States); Symms, Mark R. [GE Applied Science Laboratory, Pisa (Italy); Biagi, Laura; Tosetti, Michela [IRCCS Stella Maris, Pisa (Italy); Stara, Riccardo; Cosottini, Mirco [Imago7 Foundation, Pisa (Italy); University of Pisa, Pisa (Italy); Maggioni, Eleonora [IRCCS Scientific Institute E. Medea, Bosisio Parini, Lecco (Italy); Politecnico di Milano, Milan (Italy); Barba, Carmen [Children' s Hospital A. Meyer - University of Florence, Neuroscience Department, Florence (Italy); Guerrini, Renzo [IRCCS Stella Maris, Pisa (Italy); Children' s Hospital A. Meyer - University of Florence, Neuroscience Department, Florence (Italy)

    2014-07-15

    This contribution presents a magnetic resonance imaging (MRI) acquisition technique named Tissue Border Enhancement (TBE), whose purpose is to produce images with enhanced visualization of borders between two tissues of interest without any post-processing. The technique is based on an inversion recovery sequence that employs an appropriate inversion time to produce images where the interface between two tissues of interest is hypo-intense; therefore, tissue borders are clearly represented by dark lines. This effect is achieved by setting imaging parameters such that two neighboring tissues of interest have magnetization with equal magnitude but opposite sign; therefore, the voxels containing a mixture of each tissue (that is, the tissue interface) possess minimal net signal. The technique was implemented on a 7.0 T MRI system. This approach can assist the definition of tissue borders, such as that between cortical gray matter and white matter; therefore, it could facilitate segmentation procedures, which are often challenging on ultra-high-field systems due to inhomogeneous radiofrequency distribution. TBE allows delineating the contours of structural abnormalities, and its capabilities were demonstrated with patients with focal cortical dysplasia, gray matter heterotopia, and polymicrogyria. This technique provides a new type of image contrast and has several possible applications in basic neuroscience, neurogenetic research, and clinical practice, as it could improve the detection power of MRI in the characterization of cortical malformations, enhance the contour of small anatomical structures of interest, and facilitate cortical segmentation. (orig.)

  1. Statistical comparison of dynamic contrast-enhanced MRI pharmacokinetic models in human breast cancer.

    Science.gov (United States)

    Li, Xia; Welch, E Brian; Chakravarthy, A Bapsi; Xu, Lei; Arlinghaus, Lori R; Farley, Jaime; Mayer, Ingrid A; Kelley, Mark C; Meszoely, Ingrid M; Means-Powell, Julie; Abramson, Vandana G; Grau, Ana M; Gore, John C; Yankeelov, Thomas E

    2012-07-01

    By fitting dynamic contrast-enhanced MRI data to an appropriate pharmacokinetic model, quantitative physiological parameters can be estimated. In this study, we compare four different models by applying four statistical measures to assess their ability to describe dynamic contrast-enhanced MRI data obtained in 28 human breast cancer patient sets: the chi-square test (χ(2)), Durbin-Watson statistic, Akaike information criterion, and Bayesian information criterion. The pharmacokinetic models include the fast exchange limit model with (FXL_v(p)) and without (FXL) a plasma component, and the fast and slow exchange regime models (FXR and SXR, respectively). The results show that the FXL_v(p) and FXR models yielded the smallest χ(2) in 45.64 and 47.53% of the voxels, respectively; they also had the smallest number of voxels showing serial correlation with 0.71 and 2.33%, respectively. The Akaike information criterion indicated that the FXL_v(p) and FXR models were preferred in 42.84 and 46.59% of the voxels, respectively. The Bayesian information criterion also indicated the FXL_v(p) and FXR models were preferred in 39.39 and 45.25% of the voxels, respectively. Thus, these four metrics indicate that the FXL_v(p) and the FXR models provide the most complete statistical description of dynamic contrast-enhanced MRI time courses for the patients selected in this study.

  2. Gadodiamide injection for enhancement of MRI in the CNS. Applications, dose, field and time dependence

    Energy Technology Data Exchange (ETDEWEB)

    Aakeson, P.

    1996-10-01

    Gadodiamide injection was comparable to Gd-DTPA with regard to both safety and diagnostic efficiency in the central nervous system. The contrast effect of Gd contrast agents is higher at 1.5 T than at 0.3 T both in phantoms and patients with a maximum ratio (signal lesion/signal grey matter) more than 50% higher at 1.5 T. To achieve high contrast effect, heavily T1-weighted images are important. Prolonging the TR from 400 ms to 600 ms reduced the ratio by 15-45% depending on concentration. The effective time window for imaging of BBB (Blood-Brain Barrier) damage is between 2-5 and 25-30 minutes after injection and several scans can be performed without loss of enhancement. To provide maximum detectability of BBB damage in patients, higher doses of Gd contrast media should be useful, especially at low field strengths, as the doses used clinically today do not utilize the maximum contrast effect. High-dose (0.3 mmol/kg b.w.) contrast enhanced MRI (0.3 T) with Gadodiamide injection allowed detection of significantly more and smaller metastases (i.e. BBB damage) than standard dose (0.1 mmol/kg b.w.) High dose contrast-enhanced MRI (0.3 T) did not increase the diagnostic information for the evaluation of patients with failed back surgery syndrome compared to standard dose MRI. 55 refs, 9 figs, 10 tabs.

  3. Assessing liver function by liver enhancement during the hepatobiliary phase with Gd-EOB-DTPA-enhanced MRI at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Verloh, N.; Haimerl, M.; Schlabeck, M.; Schreyer, A.G.; Stroszczynski, C.; Fellner, C.; Wiggermann, P. [University Hospital Regensburg, Department of Radiology, Regensburg (Germany); Zeman, F. [University Hospital Regensburg, Center for Clinical Trials, Regensburg (Germany); Barreiros, A. [University Hospital Regensburg, Department of Gastroenterology, Regensburg (Germany); Loss, M. [University Hospital Regensburg, Department of Surgery, Regensburg (Germany)

    2014-05-15

    The purpose of this study was to evaluate the usefulness of Gd-EOB-DTPA-enhanced 3-T MRI to determine the hepatic functional reserve expressed by the model for end-stage liver disease (MELD) score. A total of 121 patients with normal liver function (NLF; MELD score ≤ 10) and 29 patients with impaired liver function (ILF; MELD score > 10) underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3T. T1-weighted volume interpolated breath-hold examination (VIBE) sequences with fat suppression were acquired before and 20 min after contrast injection. Relative enhancement (RE) between plain signal intensity and contrast-enhanced signal intensity was calculated and was used to determine Gd-EOB-DTPA uptake into the liver parenchyma for patients with different MELD scores. RE differed significantly (p ≤ 0.001) between patients with NLF (87.2 ± 29.5 %) and patients with ILF (45.4 ± 26.5 %). The optimal cut-off value for RE to differentiate NLF from ILF was 47.7 % (AUC 0.87). This cut-off value showed a sensitivity of 82.8 % and a specificity of 92.7 % for the differentiation of the analysed groups. Gd-EOB-DTPA uptake in hepatocytes is strongly affected by liver function. Gd-EOB-DTPA-enhanced MRI and assessment of RE during the hepatobiliary phase (HBP) may serve as a useful image-based test in liver imaging for determining regional and global liver function. (orig.)

  4. Pericentric inversion of chromosome 11 (p14.3q21) associated with developmental delays, hypopigmented skin lesions and abnormal brain MRI findings - a new case report

    Energy Technology Data Exchange (ETDEWEB)

    Zachor, D.A.; Lofton, M. [Univ. of Alabama, Birmingham (United States)

    1994-09-01

    We report 3 year old male, referred for evaluation of developmental delays. Pregnancy was complicated by oligohydramnios, proteinuria and prematurity. Medical history revealed: bilateral inguinal hernia, small scrotal sac, undescended testes, developmental delays and behavioral problems. The child had: microcephaly, facial dysmorphic features, single palmar creases, hypopigmented skin lesions of variable size, intermittent exotropia and small retracted testes. Neurological examination was normal. Cognitive level was at the average range with mild delay in his adaptive behavior. Expressive language delays and severe articulation disorder were noted, as well as clumsiness, poor control and precision of gross and fine motor skills. Chromosomal analysis of peripheral leukocytes indicated that one of the number 11 chromosomes had undergone a pericentric inversion with breakpoints on the short (p) arm at band p14.3 and the long (q) arm at band q21. An MRI of the brain showed mild delay in myelinization pattern of white matter. Chromosome 11 inversion in other sites was associated with Beckwith-Wiedemann syndrome and several malignancies. To our knowledge this is the first description of inv(11)(p14.3q21) that is associated with microcephaly, dysmorphic features, hypopigmented skin lesions and speech delay. This inversion may disrupt the expression of the involved genes. However, additional cases with the same cytogenetic anomaly are needed to explore the phenotypic significance of this disorder.

  5. Long Optical Delay Lines Enhanced by Ring Configuration in Optical Fibres

    Institute of Scientific and Technical Information of China (English)

    DONG Yong-Kang; LU Zhi-Wei; LI Qiang; GAO Wei

    2007-01-01

    A long optically controlled delay line enhanced by ring configuration is demonstrated by using the group-velocity control of signal pulses based on stimulated Brillouin scattering. In experiment, two optical fibre ring cavities are used: one is used as the Brillouin laser, providing single-mode Stokes wave as probe wave; the other is used as the Brillouin amplifier, working as slow light medium. We achieve a maximum time delay of 215ns using the ring Brillouin amplifier, five times larger than the input probe pulse width of 40ns. In the meantime, a considerable pulse broadening is observed, which agrees well with the theoretical prediction based on linear theory.

  6. Dynamic contrast-enhanced MRI improves accuracy for detecting focal splenic involvement in children and adolescents with Hodgkin disease

    Energy Technology Data Exchange (ETDEWEB)

    Punwani, Shonit; Taylor, Stuart A.; Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College London Hospital, Department of Radiology, London (United Kingdom); Cheung, King Kenneth; Skipper, Nicholas [University College London, Centre for Medical Imaging, London (United Kingdom); Bell, Nichola; Humphries, Paul D. [University College London Hospital, Department of Radiology, London (United Kingdom); Bainbridge, Alan [University College London, Department of Medical Physics and Bioengineering, London (United Kingdom); Groves, Ashley M.; Hain, Sharon F.; Ben-Haim, Simona [University College Hospital, Institute of Nuclear Medicine, London (United Kingdom); Shankar, Ananth; Daw, Stephen [University College London Hospital, Department of Paediatrics, London (United Kingdom)

    2013-08-15

    Accurate assessment of splenic disease is important for staging Hodgkin lymphoma. The purpose of this study was to assess T2-weighted imaging with and without dynamic contrast-enhanced (DCE) MRI for evaluation of splenic Hodgkin disease. Thirty-one children with Hodgkin lymphoma underwent whole-body T2-weighted MRI with supplementary DCE splenic imaging, and whole-body PET-CT before and following chemotherapy. Two experienced nuclear medicine physicians derived a PET-CT reference standard for splenic disease, augmented by follow-up imaging. Unaware of the PET-CT, two experienced radiologists independently evaluated MRI exercising a locked sequential read paradigm (T2-weighted then DCE review) and recorded the presence/absence of splenic disease at each stage. Performance of each radiologist was determined prior to and following review of DCE-MRI. Incorrect MRI findings were ascribed to reader (lesion present on MRI but missed by reader) or technical (lesion not present on MRI) error. Seven children had splenic disease. Sensitivity/specificity of both radiologists for the detection of splenic involvement using T2-weighted images alone was 57%/100% and increased to 100%/100% with DCE-MRI. There were three instances of technical error on T2-weighted imaging; all lesions were visible on DCE-MRI. T2-weighted imaging when complemented by DCE-MRI imaging may improve evaluation of Hodgkin disease splenic involvement. (orig.)

  7. The impact of bilateral salpingo-oophorectomy on breast MRI background parenchymal enhancement and fibroglandular tissue

    Energy Technology Data Exchange (ETDEWEB)

    Price, E.R. [University of California, San Francisco, Department of Radiology and Biomedical Imaging, Division of Women' s Imaging, San Francisco, California (United States); Brooks, J.D. [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Watson, E.J.; Brennan, S.B.; Morris, E.A. [Department of Radiology, Breast Imaging Section, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Comen, E.A. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2014-01-15

    The objective of this study was to evaluate the effect of bilateral salpingo-oophorectomy (BSO) on background parenchymal enhancement (BPE) and the amount of fibroglandular tissue (FGT) seen on breast MRI. Retrospective review identified 21 BRCA mutation carriers who underwent breast MRI before and after elective BSO. After exclusion of patients placed on postoperative hormone replacement therapy, there were 18 eligible patients. Blinded to surgical status, three independent readers used categorical scales to rate BPE (minimal, mild, moderate, marked) and the amount of FGT (fatty, scattered, heterogeneously dense, dense) on pre- and post-BSO MRI examinations. The sign test was used to assess for changes in the categorical ratings of BPE and FGT. Significant proportions of women demonstrated decreases in BPE and in the amount of FGT following oophorectomy (P = 0.004 and 0.02, respectively.) BPE decreases were larger and seen earlier than FGT changes. There was no significant relationship between age/body mass index and changes in BPE and FGT. BPE and the amount of FGT seen on breast MRI are significantly decreased by oophorectomy; BPE decreases to a greater extent and earlier than FGT. (orig.)

  8. Enhancing the Detection of BOLD Signal in fMRI by Reducing the Partial Volume Effect

    Directory of Open Access Journals (Sweden)

    Yiping P. Du

    2014-01-01

    Full Text Available Purpose. To investigate the advantages of reducing the partial volume effect (PVE to enhance the detection of the BOLD signal in fMRI. Methods. A linear phase term was added in k-space to obtain half-voxel shifting of 64 × 64 T2*-weighted echo-planar images. Three sets of image data shifted in the x, y, and diagonal direction, respectively, are combined with the original 64 × 64 data to form the 128 × 128 voxel-shifted interpolated data. Results. A simulation of a synthetic fMRI dataset shows that the voxel-shifted interpolation (VSI can increase the t-score up to 50% in single-voxel activations. An fMRI study (n=7 demonstrates that 20.4% of the interpolated voxels have higher t-scores than their nearest neighboring voxels in the original maps. The average increase of the t-score in these interpolated voxels is 13.3%. Conclusion. VSI yields increased sensitivity in detecting voxel-size BOLD activations, improved spatial accuracy of activated regions, and improved detection of the peak BOLD signal of an activated region. VSI can potentially be used as an alternative to the high-resolution fMRI studies in which reduction in SNR and increase in imaging time become prohibitive.

  9. Pulmonary functional MRI:an animal model study of oxygen-enhanced ventilation combined with Gd-DTPA-enhanced perfusion

    Institute of Scientific and Technical Information of China (English)

    杨健; 万明习; 郭佑民

    2004-01-01

    Background The assessment of regional pulmonary ventilation and perfusion is essential for the evaluation of a variety of lung disorders. Pulmonary ventilation MRI using inhaled oxygen as a contrast medium can be obtained with a clinical MR scanner, without additional equipment, and has been demonstrated to be a feasible means of assessing ventilation in animal models and some clinical patients. However, few studies have reported on MR ventilation-perfusion imaging. In this study, we evaluated the usefulness of oxygen-enhanced ventilation in combination with first-pass Gd-DTPA-enhanced perfusion MRI in a canine model of pulmonary embolism and airway obstruction.Methods Peripheral pulmonary embolisms were produced in eight dogs by intravenous injection of gelfoam strips at the pulmonary segmental arterial level, and airway obstructions were created in five of the dogs by inserting a self-designed balloon catheter into a secondary bronchus. Oxygen-enhanced MR ventilation images were produced by subtracting images from before and after inhalation of pure oxygen. Pulmonary perfusion MR images were acquired with a dynamic three-dimensional fast gradient-echo sequence. MR ventilation and perfusion images were read and contrasted with results from general examinations of pathological anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography. Results Regions identified as having airway obstructions matched using both MR ventilation and perfusion imaging, but regions of pulmonary embolisms were mismatched. The area of airway obstruction defects was smaller using MR ventilation imagery than that using ventilation scintigraphy. Abnormal perfusion regions due to pulmonary embolisms were divided into defective regions and reduced regions based on the time course of signal intensity changes. In the diagnosis of pulmonary embolisms with the technique of ventilation and perfusion MRI, sensitivity and specificity were 75.0% and 98.1%, respectively, and the diagnostic

  10. The significance of Gd-DTPA enhanced MRI for lumbar disc herniation; The relationship between nerve root enhancement and clinical manifestations

    Energy Technology Data Exchange (ETDEWEB)

    Taneichi, Hiroshi; Abumi, Kuniyoshi; Hirachi, Kazuhiko; Kaneda, Kiyoshi (Hokkaido Univ., Sapporo (Japan). School of Medicine)

    1993-04-01

    The purpose of this study was twofold: to determine the ability of Gd-DTPA enhanced MRI to enhance the nerve root and to determine its clinical value in lumbar disc herniation. One hundred and fifteen patients underwent enhanced MRI before and after surgery. Disturbed nerve root was demonstrated on enhanced MRI before surgery in 39.1% (45/115). Nerve root enhancement was occasionally associated with severe leg pain, but not associated with the degree of paralysis. Nerve root enhancement early after surgery was positive in 27 of 46 patients (58.7%), revealing no clinical usefulness of enhanced MRI. Non-damaged nerve root was enhanced in 7 patients (5.9%). This may reflect enhancement of root vein. Nerve root enhancement has the potential for visualizing endoneurial edema resulting from compression and inflammation of the nerve root. Enhanced MRI demonstrated lesions within the nerve root, allowing identification of damaged nerve root and diagnosis of lumbar disc herniation. (N.K.).

  11. Detection of active bile leak with Gd-EOB-DTPA enhanced MR cholangiography: Comparison of 20–25 min delayed and 60–180 min delayed images

    Energy Technology Data Exchange (ETDEWEB)

    Cieszanowski, Andrzej, E-mail: andrzej.cieszanowski@wum.edu.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Stadnik, Anna, E-mail: aniaws@yahoo.com [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Lezak, Aleksandra, E-mail: aleksandralezak@gmail.com [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Maj, Edyta, E-mail: em26@wp.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Zieniewicz, Krzysztof, E-mail: krzysztof.zieniewicz@wum.edu.pl [Chair and Department of General, Transplant and Liver Surgery, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Rowinska-Berman, Katarzyna, E-mail: kasiarowinska@wp.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Grudzinski, Ireneusz P., E-mail: ireneusz.grudzinski@wum.edu.pl [Department of Toxicology, Medical University of Warsaw, Faculty of Pharmacy, ul. Banacha 1, 02-097 Warsaw (Poland); Krawczyk, Marek, E-mail: marek.krawczyk@wum.edu.pl [Chair and Department of General, Transplant and Liver Surgery, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Rowiński, Olgierd, E-mail: olgierd.rowinski@wum.edu.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland)

    2013-12-01

    Objectives: The purpose of this study was to assess the value of contrast-enhanced magnetic resonance cholangiography (MRC) performed in different time delays after injection of gadoxetic acid disodium (Gd-EOB-DTPA) for the diagnosis of active bile leak. Methods: This retrospective analysis included Gd-EOB-DTPA enhanced MR images of 34 patients suspected of bile leak. Images were acquired 20–25 min after Gd-EOB-DTPA injection. If there was inadequate contrast in the bile ducts then delayed images after 60–90 min and 150–180 min were obtained. Results were correlated with intraoperative findings, ERCP results, clinical data, laboratory tests, and follow-up examinations. Results: Gd-EOB-DTPA enhanced MRC yielded an overall sensitivity of 96.4%, specificity of 100% and accuracy of 97.1% for the diagnosis of an active bile leak. The sensitivity of 20–25 min delayed MR images was 42.9%, of combined 20–25 min and 60–90 min delayed images was 92.9% and of combined 20–25 min, 60–90 min and 150–180 min delayed images was 96.4%. Conclusions: Gd-EOB-DTPA enhanced MRC utilizing delayed phase images was effective for detecting the presence and location of active bile leaks. The images acquired 60–180 min post-injection enabled identification of bile leaks even in patients with a dilated biliary system or moderate liver dysfunction.

  12. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), after slipped capital femoral epiphysis

    Energy Technology Data Exchange (ETDEWEB)

    Zilkens, Christoph, E-mail: Christoph.Zilkens@med.uni-duesseldorf.de [Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Miese, Falk [Department of Radiology, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Bittersohl, Bernd; Jaeger, Marcus; Schultz, Johannes [Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Holstein, Arne [Department of Radiology, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany); Kim, Young-jo; Millis, Michael B. [Department of Orthopaedic Surgery, Childrens Hospital Boston, Harvard Medical, School, 300 Longwood Avenue, Boston, MA 02115 (United States); Mamisch, Tallal C. [Department of Orthopaedic Surgery, Inselspital Bern, University Hospital, Bern (Switzerland); Krauspe, Ruediger [Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstrasse 5, 40225 Duesseldorf (Germany)

    2011-09-15

    Objective: The aim of this study was to assess the glycosaminoglycan (GAG) content in hip joint cartilage in mature hips with a history of slipped capital femoral epiphysis (SCFE) using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Methods: 28 young-adult subjects (32 hips) with a mean age of 23.8 {+-} 4.0 years (range: 18.1-30.5 years) who were treated for mild or moderate SCFE in adolescence were included into the study. Hip function and clinical symptoms were evaluated with the Harris hip score (HHS) system at the time of MRI. Plain radiographic evaluation included Tonnis grading, measurement of the minimal joint space width (JSW) and alpha-angle measurement. The alpha-angle values were used to classify three sub-groups: group 1 = subjects with normal femoral head-neck offset (alpha-angle <50{sup o}), group 2 = subjects with mild offset decrease (alpha-angle 50{sup o}-60{sup o}), and group 3 = subjects with severe offset decrease (alpha-angle >60{sup o}). Results: There was statistically significant difference noted for the T1{sub Gd} values, lateral and central, between group 1 and group 3 (p-values = 0.038 and 0.041). The T1{sub Gd} values measured within the lateral portion were slightly lower compared with the T1{sub Gd} values measured within the central portion that was at a statistically significance level (p-value <0.001). HHS, Tonnis grades and JSW revealed no statistically significant difference. Conclusion: By using dGEMRIC in the mid-term follow-up of SCFE we were able to reveal degenerative changes even in the absence of joint space narrowing that seem to be related to the degree of offset pathology. The dGEMRIC technique may be a potential diagnostic modality in the follow-up evaluation of SCFE.

  13. Incidence of enhancement of the optic nerve/sheath complex in fat-suppression orbit MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Kyu; Yoon, Kwon Ha; Choi, Choong Gon; Suh, Dae Chul [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    1995-04-15

    To elucidate the incidence of Gd-DTPA enhancement of the optic nerve/sheath complex (ONC) in patients with various ophthalmopathies using fat-suppression MRI. Orbit MRI with fat-suppression technique (ChemSat) was performed in 58 patients with normal and various orbital lesions. The fat-suppression MR was done with and without Gd-DTPA injection in all cases. MR findings were reviewed retrospectively in a blind fashion with respect to presence or absence of contrast enhancement of the ONC. Contrast enhancement of the ONC was seen in 86% (6/7) of cavernous sinus lesions, 80% (8/10) of intraconal lesions excluding the ONC, 57% (16/28) of ONC lesions, 38% (3/8) of ocular lesions, and 2% (1/55) of normal orbits. The ONC enhancement was the most common in optic nerve/sheath tumors (10/10), and pseudotumors (6/6), cavernous sinus dural arteriovenous malformations (3/3) and cavernous sinus thrombosis (2/2), and less frequently seen in optic neuritis (3/14). Enhancement of the ONC may be seen in lesions of the cavernous sinus and orbit other than optic nerve/sheath lesion.

  14. Security-enhanced chaos communication with time-delay signature suppression and phase encryption.

    Science.gov (United States)

    Xue, Chenpeng; Jiang, Ning; Lv, Yunxin; Wang, Chao; Li, Guilan; Lin, Shuqing; Qiu, Kun

    2016-08-15

    A security-enhanced chaos communication scheme with time delay signature (TDS) suppression and phase-encrypted feedback light is proposed, in virtue of dual-loop feedback with independent high-speed phase modulation. We numerically investigate the property of TDS suppression in the intensity and phase space and quantitatively discuss security of the proposed system by calculating the bit error rate of eavesdroppers who try to crack the system by directly filtering the detected signal or by using a similar semiconductor laser to synchronize the link signal and extract the data. The results show that TDS embedded in the chaotic carrier can be well suppressed by properly setting the modulation frequency, which can keep the time delay a secret from the eavesdropper. Moreover, because the feedback light is encrypted, without the accurate time delay and key, the eavesdropper cannot reconstruct the symmetric operation conditions and decode the correct data.

  15. Safety of meglumine gadoterate (Gd-DOTA)-enhanced MRI compared to unenhanced MRI in patients with chronic kidney disease (RESCUE study)

    Energy Technology Data Exchange (ETDEWEB)

    Deray, Gilbert [Pitie Salpetriere Hospital, Department of Nephrology, Paris cedex 13 (France); Rouviere, Olivier [Hopital E. Herriot, Universite de Lyon, Hospices Civils de Lyon, Department of Urinary and Vascular Imaging, Lyon (France); Universite Lyon 1, faculte de medecine Lyon Est, Lyon (France); Bacigalupo, Lorenzo [E.O. Ospedali Galliera, Radiology Department, Genova (Italy); Maes, Bart [Heilig Hartziekenhuis Roeselare, Department of Nephrology, Roeselare (Belgium); Hannedouche, Thierry [University Hospitals, Department of Nephrology, Strasbourg (France); Vrtovsnik, Francois [Bichat Hospital, Department of Nephrology, Paris (France); Rigothier, Claire [Pellegrin Hospital, Department of Nephrology Transplantation Dialysis, Bordeaux (France); Billiouw, Jean-Marie [Onze Lieve Vrouw Ziekenhuis, Department of Nephrology, Aalst (Belgium); Campioni, Paolo [Azienda Ospedaliero-Universitaria Sant' Anna, Ferrara (Italy); Ferreiros, Joaquin [Hospital Clinico de San Carlos, Servicio de Radiodiagnostico, Madrid (Spain); Devos, Daniel [Gent University Hospital, Department of Radiology, Gent (Belgium); Alison, Daniel [Trousseau Hospital, Department of Radiology, Tours (France); Glowacki, Francois [University Hospitals, Department of Nephrology, Lille (France); Boffa, Jean-Jacques [Tenon Hospital, Department of Nephrology and Dialysis, Paris (France); Marti-Bonmati, Luis [University of Valencia, Department of Radiology, Valencia (Spain)

    2013-05-15

    To prospectively compare the renal safety of meglumine gadoterate (Gd-DOTA)-enhanced magnetic resonance imaging (MRI) to a control group (unenhanced MRI) in high-risk patients. Patients with chronic kidney disease (CKD) scheduled for MRI procedures were screened. The primary endpoint was the percentage of patients with an elevation of serum creatinine levels, measured 72 {+-} 24 h after the MRI procedure, by at least 25 % or 44.2 {mu}mol/l (0.5 mg/dl) from baseline. A non-inferiority margin of the between-group difference was set at -15 % for statistical analysis of the primary endpoint. Main secondary endpoints were the variation in serum creatinine and eGFR values between baseline and 72 {+-} 24 h after MRI and the percentage of patients with a decrease in eGFR of at least 25 % from baseline. Patients were screened for signs of nephrogenic systemic fibrosis (NSF) at 3-month follow-up. Among the 114 evaluable patients, one (1.4 %) in the Gd-DOTA-MRI group and none in the control group met the criteria of the primary endpoint [{Delta} = -1.4 %, 95%CI = (-7.9 %; 6.7 %)]. Non-inferiority was therefore demonstrated (P = 0.001). No clinically significant differences were observed between groups for the secondary endpoints. No serious safety events (including NSF) were noted. Meglumine gadoterate did not affect renal function and was a safe contrast agent in patients with CKD. (orig.)

  16. FDG uptake on PET and enhancement on CT or MRI in hepatocellular carcinoma (HCC)

    Energy Technology Data Exchange (ETDEWEB)

    Ko, K. H.; Yun, M.; Kim, M. J.; Ryu, Y. H.; Lee, J. D. [Yonsei University Medical Center, Seoul (Korea, Republic of)

    2002-07-01

    To correlate between FDG PET and enhancement pattern on CT and MRI and assess the factors affecting FDG uptake in HCC. Thirty seven nontreated HCC from 34 pts (M:F=30:4, mean age 53) were enrolled. All cases were histologically diagnosed and classified according to Edmonson and Steiner's grading. Tumor FDG uptake was visually assessed on a scale of 0 to 3 compared to the adjacent liver. (0liver and 3>>liver) and was semi-quantitatively analyzed using SUV. Enhancement pattern on CT and MRI was classified into 3 groups according to signal intensity or density in arterial and portal phase (GroupI: hyperintense-hypointense, GroupII: isointense-hypointense, GroupIII: hypointense-hypointense). Tumor FDG uptake was correlated with enhancement pattern, grade, size and serum aFP level. The tumor ranged from 1.5cm to 20cm. Of the 37 cases, 19(51%) had positive FDG uptake (2 or 3), while 18(49%) were negative (0 or 1). The correlation between FDG uptake and enhancement pattern was statistically insignificant. Lower FDG uptake was associated with lower tumor grade and/or smaller tumor size (P<0.005). FDG uptake of HCC seems to be useful in predicting the differentiation of the tumor and may be prognostic. Although the significance of dynamic enhancement pattern on CT or MRI is yet controversial, it has no specific correlation with FDG uptake and grade on the tumor in this study.

  17. Contrast-enhanced ultra-high-field liver MRI: A feasibility trial

    Energy Technology Data Exchange (ETDEWEB)

    Umutlu, Lale, E-mail: Lale.Umutlu@uk-essen.de [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen (Germany); Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Bitz, Andreas K.; Maderwald, Stefan; Orzada, Stephan; Kinner, Sonja; Kraff, Oliver; Brote, Irina; Ladd, Susanne C.; Schroeder, Tobias; Forsting, Michael; Antoch, Gerald; Ladd, Mark E. [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen (Germany); Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Quick, Harald H. [Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Institute of Medical Physics, University Nuernberg-Erlangen (Germany); Lauenstein, Thomas C. [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen (Germany); Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany)

    2013-05-15

    The aim of this study was to investigate the feasibility of dynamic contrast-enhanced 7 T MRI of the liver using an eight-channel radiofrequency (RF) transmit/receive body-coil. 16 healthy subjects were examined on a 7 T MR system utilizing a custom-built eight-channel RF body-coil suitable for RF-shimming. The following data were acquired: (1) steady state free precession imaging, (2) T2w turbo spin echo imaging, (3) T1w in and opposed-phase imaging, (4) T1w 3D FLASH images pre-contrast and in arterial, portal-venous and venous phase and (5) a fat-saturated pre- and post-contrast 2D FLASH sequence. Visual evaluation of (1) the delineation of liver vasculature, (2) the overall image quality, and (3) artifact presence and consequent image impairment was performed. SNR of the liver parenchyma was measured for the contrast-enhanced 2D and 3D FLASH sequences. For statistical analysis, a Wilcoxon-Rank Test was used. Best delineation of non-enhanced liver vasculature and overall image quality was found for 2D FLASH MRI, with only slight improvement in vessel conspicuity after the application of contrast media. T2-weighted TSE imaging remained strongly impaired, falling short of diagnostic relevance and precluding a clinical application. Our results demonstrate the feasibility and diagnostic potential of dedicated contrast-enhanced 7 T liver MRI as well as the potential for non-contrast-enhanced angiographic application.

  18. Contrast-enhanced MRI of subchondral cysts in patients with or at risk for knee osteoarthritis: The MOST study

    Energy Technology Data Exchange (ETDEWEB)

    Crema, M.D., E-mail: michelcrema@gmail.co [Department of Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Building, 3rd Floor, Boston, MA 02118 (United States); Roemer, F.W., E-mail: frank.roemer@klinikum-augsburg.d [Department of Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Building, 3rd Floor, Boston, MA 02118 (United States); Department of Radiology, Klinikum Augsburg, Stenglinstrasse 2, Augsburg 86156 (Germany); Marra, M.D., E-mail: monicadiasmarra@gmail.co [Department of Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Building, 3rd Floor, Boston, MA 02118 (United States); Niu, J., E-mail: niujp@bu.ed [Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany Street, X Building, Suite 200, Boston, MA 02118 (United States); Lynch, J.A., E-mail: jlynch@psg.ucsf.ed [Department of Epidemiology and Biostatistics, University of California at San Francisco, 185 Berry Street, Lobby 5, Suite 5700, San Francisco, CA 94107 (United States); Felson, D.T., E-mail: dfelson@bu.ed [Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany Street, X Building, Suite 200, Boston, MA 02118 (United States); Guermazi, A., E-mail: ali.guermazi@bmc.or [Department of Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Building, 3rd Floor, Boston, MA 02118 (United States)

    2010-07-15

    Objective: The aim of the study was (1) to evaluate contrast enhancement patterns of subchondral cysts on magnetic resonance imaging and (2) to discuss possible radiological explanations of cyst enhancement based on existing theories of subchondral cyst formation in osteoarthritis. Materials and methods: The Multicenter Osteoarthritis Study (MOST) is a NIH-funded longitudinal observational study for individuals who have or are at high risk for knee osteoarthritis. All subjects with available non-enhanced and contrast-enhanced MRI were included. The tibiofemoral and patellofemoral joints were divided in 14 subregions. The presence and size of subchondral cysts and bone marrow edema-like lesions (BMLs) were scored semiquantitatively in each subregion on non-contrast-enhanced MRI from 0 to 3. Enhancement of subchondral cysts was evaluated on contrast-enhanced MRI as grade 0 (absent), grade 1 (partial enhancement), or grade 2 (full enhancement). The adjacent articular cartilage was scored in each subregion on non-enhanced MRI as grade 0 (intact), grade 1 (partial thickness loss), or grade 2 (full thickness loss). Results: Four hundred knees were included (1 knee per person, 5600 subregions). Subchondral cysts were detected in 260 subregions (4.6%). After intravenous contrast administration, 245 cysts (94.2%) showed full enhancement, 12 (4.6%) showed partial enhancement and 3 (1.2%) showed no enhancement. Enhancing BMLs were found in 237 (91.2%) subregions containing cysts, which were located adjacent or in the middle of BMLs. In 121 subregions (46.5%) having cysts, no adjacent full thickness cartilage loss was detected. Conclusion: Most subchondral cysts demonstrated full or partial contrast enhancement, and were located adjacent or in the midst of enhancing BMLs. As pure cystic lesions are not expected to enhance on MRI, the term 'subchondral cyst-like bone marrow lesion' might be appropriate to describe these lesions.

  19. In vivo detection of neuroarchitecture in the rodent brain using manganese-enhanced MRI.

    Science.gov (United States)

    Aoki, Ichio; Wu, Yi-Jen Lin; Silva, Afonso C; Lynch, Ronald M; Koretsky, Alan P

    2004-07-01

    Visualizing brain anatomy in vivo could provide insight into normal and pathophysiology. Here it is demonstrated that neuroarchitecture can be detected in the rodent brain using MRI after systemic MnCl2. Administration of MnCl2 leads to rapid T1 enhancement in the choroid plexus and circumventricular organs, which spreads to the CSF space in ventricles and periventricular tissue. After 1 day, there was MRI enhancement throughout the brain with high intensity in the pituitary, olfactory bulb, cortex, basal forebrain, hippocampus, basal ganglia, hypothalamus, amygdala, and cerebellum. Contrast obtained enabled visualization of specific features of neuroarchitecture. The arrowhead structure of the dentate gyrus as well as the CA1-CA3 region of the hippocampus and layers in cortex, cerebellum, as well as the olfactory bulb could be readily observed. Preliminary assignments of olfactory bulb layers, cortical layers in frontal and somatosensory cortex, and cerebellum were made. Systemic MnCl2 leads to MRI visualization of neuroarchitecture nondestructively. Copyright 2004 Elsevier Inc.

  20. Nanoparticle Enhanced MRI Scanning to Detect Cellular Inflammation in Experimental Chronic Renal Allograft Rejection

    Directory of Open Access Journals (Sweden)

    S. R. Alam

    2015-01-01

    Full Text Available Objectives. We investigated whether ultrasmall paramagnetic particles of iron oxide- (USPIO- enhanced magnetic resonance imaging (MRI can detect experimental chronic allograft damage in a murine renal allograft model. Materials and Methods. Two cohorts of mice underwent renal transplantation with either a syngeneic isograft or allograft kidney. MRI scanning was performed prior to and 48 hours after USPIO infusion using T2∗-weighted protocols. R2∗ values were calculated to indicate the degree of USPIO uptake. Native kidneys and skeletal muscle were imaged as reference tissues and renal explants analysed by histology and electron microscopy. Results. R2∗ values in the allograft group were higher compared to the isograft group when indexed to native kidney (median 1.24 (interquartile range: 1.12 to 1.36 versus 0.96 (0.92 to 1.04, P<0.01. R2∗ values were also higher in the allograft transplant when indexed to skeletal muscle (6.24 (5.63 to 13.51 compared to native kidney (2.91 (1.11 to 6.46 P<0.05. Increased R2∗ signal in kidney allograft was associated with macrophage and iron staining on histology. USPIO were identified within tissue resident macrophages on electron microscopy. Conclusion. USPIO-enhanced MRI identifies macrophage.

  1. Enhanced MRI in compressed lumbosacral nerve root; Alteration of vascular peameability in nerve root

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Tomofumi; Yoshizawa, Hidezo; Nakai, Sadaaki; Kobayashi, Shigeru; Hachiya, Hiromichi; Nakagawa, Masato; Nishimoto, Satoshi (Fujita Health Univ., Toyoake, Aichi (Japan). School of Medicine)

    1993-04-01

    The study was undertaken to assess how enhanced MRI reflects pathophysiology of the nerve root. In fundamental study, the seventh left lumbar nerve root was compressed by a clip for one hour in 10 mongrel dogs. Thirty min after removal of mechanical compression, gadolinium and Evans blue albumin (EBA) were iv injected. Then, the dogs were killed 10 min later. A mass of lumbosacral nerve root was removed for MR imaging. In addition, nerve root slices were prepared to examine changes in vascular permeability of EBA under microscopy. The compression area of nerve root was seen as hyperintensity on enhanced MRI, corresponding to extravascular leakage of EBA that resulted from the damaged blood-nerve barrier, i.e., edema within the root on microscope. In a clinical setting, 27 patients with lumbar disc herniation underwent MRI for the observation of the nerve root. In 8 of these 27 patients, the nerve root was seen as hyperintensity. This suggests that approximately one third of such patients may have edema within the nerve root. (N.K.).

  2. Tryptophan PET predicts spatial and temporal patterns of post-treatment glioblastoma progression detected by contrast-enhanced MRI.

    Science.gov (United States)

    Bosnyák, Edit; Kamson, David O; Robinette, Natasha L; Barger, Geoffrey R; Mittal, Sandeep; Juhász, Csaba

    2016-01-01

    Amino acid PET is increasingly utilized for the detection of recurrent gliomas. Increased amino acid uptake is often observed outside the contrast-enhancing brain tumor mass. In this study, we evaluated if non-enhancing PET+ regions could predict spatial and temporal patterns of subsequent MRI progression in previously treated glioblastomas. Twelve patients with a contrast-enhancing area suspicious for glioblastoma recurrence on MRI underwent PET scanning with the amino acid radiotracer alpha-[(11)C]-methyl-L-tryptophan (AMT). Brain regions showing increased AMT uptake in and outside the contrast-enhancing volume were objectively delineated to include high uptake consistent with glioma (as defined by previous studies). Volume and tracer uptake of such non-enhancing PET+ regions were compared to spatial patterns and timing of subsequent progression of the contrast-enhancing lesion, as defined by serial surveillance MRI. Non-enhancing PET+ volumes varied widely across patients and extended up to 24 mm from the edge of MRI contrast enhancement. In ten patients with clear progression of the contrast-enhancing lesion, the non-enhancing PET+ volumes predicted the location of new enhancement, which extended beyond the PET+ brain tissue in six. In two patients, with no PET+ area beyond the initial contrast enhancement, MRI remained stable. There was a negative correlation between AMT uptake in non-enhancing brain and time to subsequent progression (r = -0.77, p = 0.003). Amino acid PET imaging could complement MRI not only for detecting glioma recurrence but also predicting the location and timing of subsequent tumor progression. This could support decisions for surgical intervention or other targeted therapies for recurrent gliomas.

  3. Demonstration of the reproducibility of free-breathing diffusion-weighted MRI and dynamic contrast enhanced MRI in children with solid tumours: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Keiko; Jerome, Neil P.; Collins, David J.; Orton, Matthew R.; D' Arcy, James A.; Leach, Martin O. [Cancer Research UK Cancer Imaging Centre at The Institute of Cancer Research, London (United Kingdom); Wallace, Toni; Koh, Dow-Mu [Royal Marsden Hospital, Department of Radiology, London, England (United Kingdom); Moreno, Lucas [The Institute of Cancer Research, Paediatric Drug Development Team, Divisions of Cancer Therapeutics and Clinical Studies, London (United Kingdom); Spanish National Cancer Research Centre (CNIO), Clinical Research Programme, Madrid (Spain); The Royal Marsden NHS Foundation Trust, Paediatric Drug Development Unit, Children and Young People' s Unit, Sutton (United Kingdom); Pearson, Andrew D.J.; Marshall, Lynley V.; Carceller, Fernando; Zacharoulis, Stergios [The Institute of Cancer Research, Paediatric Drug Development Team, Divisions of Cancer Therapeutics and Clinical Studies, London (United Kingdom); The Royal Marsden NHS Foundation Trust, Paediatric Drug Development Unit, Children and Young People' s Unit, Sutton (United Kingdom)

    2015-09-15

    The objectives are to examine the reproducibility of functional MR imaging in children with solid tumours using quantitative parameters derived from diffusion-weighted (DW-) and dynamic contrast enhanced (DCE-) MRI. Patients under 16-years-of age with confirmed diagnosis of solid tumours (n = 17) underwent free-breathing DW-MRI and DCE-MRI on a 1.5 T system, repeated 24 hours later. DW-MRI (6 b-values, 0-1000 sec/mm{sup 2}) enabled monoexponential apparent diffusion coefficient estimation using all (ADC{sub 0-1000}) and only ≥100 sec/mm{sup 2} (ADC{sub 100-1000}) b-values. DCE-MRI was used to derive the transfer constant (K{sup trans}), the efflux constant (k{sub ep}), the extracellular extravascular volume (v{sub e}), and the plasma fraction (v{sub p}), using a study cohort arterial input function (AIF) and the extended Tofts model. Initial area under the gadolinium enhancement curve and pre-contrast T{sub 1} were also calculated. Percentage coefficients of variation (CV) of all parameters were calculated. The most reproducible cohort parameters were ADC{sub 100-1000} (CV = 3.26 %), pre-contrast T{sub 1} (CV = 6.21 %), and K{sup trans} (CV = 15.23 %). The ADC{sub 100-1000} was more reproducible than ADC{sub 0-1000}, especially extracranially (CV = 2.40 % vs. 2.78 %). The AIF (n = 9) derived from this paediatric population exhibited sharper and earlier first-pass and recirculation peaks compared with the literature's adult population average. Free-breathing functional imaging protocols including DW-MRI and DCE-MRI are well-tolerated in children aged 6 - 15 with good to moderate measurement reproducibility. (orig.)

  4. Enhanced brain connectivity in math-gifted adolescents: An fMRI study using mental rotation.

    Science.gov (United States)

    Prescott, James; Gavrilescu, Maria; Cunnington, Ross; O'Boyle, Michael W; Egan, Gary F

    2010-12-01

    Mathematical giftedness is a form of intelligence related to enhanced mathematical reasoning that can be tested using a variety of numerical and spatial tasks. A number of neurobiological mechanisms related to exceptional mathematical reasoning ability have been postulated, including enhanced brain connectivity. We aimed to further investigate this possibility by comparing a group of mathematically gifted adolescents with an average math ability control group performing mental rotation of complex three-dimensional block figures. Functional magnetic resonance imaging (fMRI) data were collected and differences in intrahemispheric and interhemispheric connectivity between the groups were assessed using structural equation modeling (SEM). The math-gifted showed heightened intrahemispheric frontoparietal connectivity, as well as enhanced interhemispheric frontal connectivity between the dorsolateral prefrontal and premotor cortex. These enhanced connectivity patterns are consistent with previous studies linking increased activation of the frontal and parietal regions with high fluid intelligence, and may be a unique neural characteristic of the mathematically gifted brain.

  5. T₁ and T₂ dual-mode MRI contrast agent for enhancing accuracy by engineered nanomaterials.

    Science.gov (United States)

    Shin, Tae-Hyun; Choi, Jin-sil; Yun, Seokhwan; Kim, Il-Sun; Song, Ho-Taek; Kim, Youngmee; Park, Kook In; Cheon, Jinwoo

    2014-04-22

    One of the holy grails in biomedical imaging technology is to achieve accurate imaging of biological targets. The development of sophisticated instrumentation and the use of contrast agents have improved the accuracy of biomedical imaging. However, the issue of false imaging remains a problem. Here, we developed a dual-mode artifact filtering nanoparticle imaging agent (AFIA) that comprises a combination of paramagnetic and superparamagnetic nanomaterials. This AFIA has the ability to perform "AND logic gate" algorithm to eliminate false errors (artifacts) from the raw images to enhance accuracy of the MRI. We confirm the artifact filtering capability of AFIA in MRI phantoms and further demonstrate that artifact-free imaging of stem cell migration is possible in vivo.

  6. Value of whole body MRI and dynamic contrast enhanced MRI in the diagnosis, follow-up and evaluation of disease activity and extent in multiple myeloma

    Energy Technology Data Exchange (ETDEWEB)

    Dutoit, Julie C., E-mail: Julie.Dutoit@UGent.be; Vanderkerken, Matthias A., E-mail: Matthias.Vanderkerken@UGent.be; Verstraete, Koenraad L., E-mail: Koenraad.Verstraete@UGent.be

    2013-09-15

    Purpose: To evaluate the significance of dynamic contrast enhanced MRI (DCE-MRI) and whole body MRI (WB-MRI) in the diagnosis, prognosis and assessment of therapy for patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). Materials and methods: The retrospective study includes 219 patients providing 463 WB-MRI and DCE-MRI investigations for the subgroups MGUS (n = 70), MM active disease (n = 126; this includes 70 patients with new diagnosis of MM, according to the International Staging System (ISS): 41.4% ISS stage I, 20.0% ISS stage II, 7.1% ISS stage III, 31.4% insufficient for staging; and 56 patients with ‘(re-)active disease’: 16.07% relapse, 32.14% progressive disease and 51.79% stable disease) and MM remission (n = 23; 60.87% complete remission, 17.39% very good partial remission and 21.74% partial remission). Investigations of patients with hereditary multiple exostoses (n = 5), neurofibromatosis (n = 7) and healthy persons (n = 9) were added as control subjects (n = 21). WB-MRI evaluation was done by evaluating thirteen skeletal regions, providing a ‘skeletal score’. DCE-MRI images of the spine, were analyzed with regions-of-interest and time-intensity-curves (TIC). Results: All TIC parameters can significantly differentiate between the predefined subgroups (p < 0.001). One hundred days after autologous stem cell transplantation a 75% decrease of the slope wash-in value (p < 0.001) can be seen. A cubic regression trend between ‘skeletal score’ and slope wash-in (adj.R{sup 2} = 0.412) could demonstrate a significant increase bone marrow perfusion if MM affects more than 10 skeletal regions (p < 0.001), associated with a poorer prognosis (p < 0.001). Conclusion: DCE-MRI evaluation of the spine is useful for diagnosis of MM, follow-up after stem cell transplantation and evaluation of disease activity. A combined evaluation with WB-MRI and DCE-MRI provides additional micro-vascular information on the

  7. High-dose gadolinium-enhanced MRI for diagnosis of meningeal metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kallmes, D.F. [Department of Radiology, Box 170, University of Virginia Health Sciences Center, Charlottesville, VA 22908 (United States); Gray, L. [Department of Radiology, Duke University Medical Center, Durham, NC (United States); Glass, J.P. [Department of Medicine, Veterans Administration Hospital, Gainesville, Florida (United States)

    1998-01-01

    We compared high-dose (0.3 mmol/kg) and standard-dose (0.1 mmol/kg) gadolinium-enhanced MRI for diagnosis of meningeal metastases in 12 patients with suspected meningeal metastases. They were imaged with both standard-dose and high-dose gadolinium. All patients with abnormal meningeal enhancement underwent at least one lumbar puncture for cerebrospinal fluid (CSF) cytology, while patients with normal meningeal enhancement were followed clinically. All patients with negative CSF cytology also were followed clinically. A single observer reviewed all the images, with specific attention to the enhancement pattern of the meninges. Abnormal leptomeningeal enhancement was present in three cases, and abnormal pachymeningeal enhancement in three other patients. All of these patients had abnormal CSF analyses. In two of the three cases of abnormal leptomeningeal enhancement the disease was more evident on high-dose than on standard-dose imaging; in one case the abnormal enhancement was visible only on high-dose imaging. In one of the three cases with abnormal pachymeningeal enhancement, the disease was evident prospectively only with high-dose imaging. (orig.) With 3 figs., 10 refs.

  8. Contrast-enhanced 3D MRI of lung perfusion in children with cystic fibrosis - initial results

    Energy Technology Data Exchange (ETDEWEB)

    Eichinger, Monika; Puderbach, Michael; Zuna, Ivan; Kauczor, Hans-Ulrich [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Heidelberg (Germany); Fink, Christian [Institut fuer Klinische Radiologie, Klinikum der LMU Grosshadern, Department of Radiology, Muenchen (Germany); Gahr, Julie; Mueller, Frank-Michael [Universitaetskinderklinik III Heidelberg, Department of Pediatric Pulmonology, Cystic Fibrosis Centre and Infectious Diseases, Heidelberg (Germany); Ley, Sebastian [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Heidelberg (Germany); Universitaetskinderklinik Heidelberg, Department of Pediatric Radiology, Heidelberg (Germany); Plathow, Christian [Eberhard-Karls University, Department of Diagnostic Radiology, Tuebingen (Germany); Tuengerthal, Siegfried [Thoraxklinik am Universitaetsklinikum Heidelberg, Department of Radiology, Heidelberg (Germany)

    2006-10-15

    This paper is a feasibility study of magnetic resonance imaging (MRI) of lung perfusion in children with cystic fibrosis (CF) using contrast-enhanced 3D MRI. Correlation assessment of perfusion changes with structural abnormalities. Eleven CF patients (9 f, 2 m; median age 16 years) were examined at 1.5 T. Morphology: HASTE coronal, transversal (TR/TE/{alpha}/ST: 600 ms/28 ms/180 /6 mm), breath-hold 18 s. Perfusion: Time-resolved 3D GRE pulse sequence (FLASH, TE/TR/{alpha}: 0.8/1.9 ms/40 ), parallel imaging (GRAPPA, PAT 2). Twenty-five data sets were acquired after intravenous injection of 0.1 mmol/kg body weight of gadodiamide, 3-5 ml/s. A total of 198 lung segments were analyzed by two radiologists in consensus and scored for morphological and perfusion changes. Statistical analysis was performed by Mantel-Haenszel chi-square test. Results showed that perfusion defects were observed in all patients and present in 80% of upper, and 39% of lower lobes. Normal lung parenchyma showed homogeneous perfusion (86%, P<0.0001). Severe morphological changes led to perfusion defects (97%, P<0.0001). Segments with moderate morphological changes showed normal (53%) or impaired perfusion (47%). In conclusion, pulmonary perfusion is easy to judge in segments with normal parenchyma or severe changes. In moderately damaged segments, MRI of lung perfusion may help to better assess actual functional impairment. Contrast-enhanced 3D MRI of lung perfusion has the potential for early vascular functional assessment and therapy control in CF patients. (orig.)

  9. Cx30.2 enhancer analysis identifies Gata4 as a novel regulator of atrioventricular delay

    Science.gov (United States)

    Munshi, Nikhil V.; McAnally, John; Bezprozvannaya, Svetlana; Berry, Jeff M.; Richardson, James A.; Hill, Joseph A.; Olson, Eric N.

    2009-01-01

    Summary The cardiac conduction system comprises a specialized tract of electrically coupled cardiomyocytes responsible for impulse propagation through the heart. Abnormalities in cardiac conduction are responsible for numerous forms of cardiac arrhythmias, but relatively little is known about the gene regulatory mechanisms that control the formation of the conduction system. We demonstrate that a distal enhancer for the connexin 30.2 (Cx30.2, also known as Gjd3) gene, which encodes a gap junction protein required for normal atrioventricular (AV) delay in mice, is necessary and sufficient to direct expression to the developing AV conduction system (AVCS). Moreover, we show that this enhancer requires Tbx5 and Gata4 for proper expression in the conduction system, and Gata4+/- mice have short PR intervals indicative of accelerated AV conduction. Thus, our results implicate Gata4 in conduction system function and provide a clearer understanding of the transcriptional pathways that impact normal AV delay. PMID:19592579

  10. Spectral enhancement of single attosecond pulses by time-delayed control field

    CERN Document Server

    Chu, Wei-Chun

    2012-01-01

    An optical coherent control scheme has been proposed where an extreme ultraviolet single attosecond pulse (SAP) propagates through a dense helium gas dressed by a time-delayed femtosecond laser pulse. The laser pulse couples the 2s2p(^1P) and 2s^2(^1S) autoionizing states when the SAP excites the 2s2p state. After going through the gas, the spectral and temporal profiles of the SAP are strongly distorted. A narrowed but enhanced spike in the spectrum shows up for specific intensities and time delays of the laser, which exemplifies the control of a broadband photon wave packet by an ultrashort dressing field for the first time. We analyze the photon and electron dynamics and conclude on the dressing condition that maximizes this enhancement. The result demonstrates new possibilities of attosecond optical control.

  11. Tuberculosis versus lymphoma in the abdominal lymph nodes: A comparative study using contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Heng, E-mail: shaoheng617@126.com [Department of Radiology, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China); Yang, Zhi-gang, E-mail: yangzg6666@yahoo.com.cn [Department of Radiology, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China); State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China); Deng, Wen, E-mail: dengwen0913@163.com [Department of Radiology, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China); Chen, Jing, E-mail: yzqdcj@126.com [Department of Radiology, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China); Tang, Si-shi, E-mail: cecilalucky@126.com [Department of Radiology, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China); Wen, Ling-yi, E-mail: lizzievane@126.com [Department of Radiology, West China Hospital, Sichuan University, 37 GuoXue Street, Chengdu, Sichuan 610041 (China)

    2012-10-15

    Purpose: The purpose of this study was to determine the differential characteristics on MRI between tuberculosis and lymphoma in abdominal lymph nodes. Materials and methods: We conducted a retrospective analysis for the counter, size, signal intensity, enhancement patterns, and anatomic distribution of lymph nodes in 57 consecutive patients with documented tuberculosis (28 patients; 49.1%) and newly diagnosed, untreated lymphoma (29 patients; 50.9%). Results: Twenty-four cases (85.7%) in the tuberculosis group were hyperintense on T2-weighted images and either hypointense or isointense on T1-weighted images with respect to the abdominal wall muscle. All cases in the lymphoma group were hyperintense on T2-weighted images and isointense on T1-weighted images with respect to the abdominal wall muscle. Concerning the main anatomic distribution of lymph nodes, the lymph nodes in the lower paraaortic region were more frequently involved in the lymphoma group (48.3%) than in tuberculosis (17.9%, p < 0.05). Moreover, mesenteric lymph nodes were more often involved in tuberculosis (32.1%) than in lymphoma (6.9%, p < 0.05). Tuberculous lymphadenopathy showed predominantly peripheral enhancement, frequently with a multilocular appearance; whereas lymphomatous adenopathy often demonstrated uniform homogeneous enhancement (all p < 0.001). Conclusion: Contrast-enhanced MRI can be useful in differentiation between these two entities.

  12. Age dependence of spleen- and muscle-corrected hepatic signal enhancement on hepatobiliary phase gadoxetate MRI

    Energy Technology Data Exchange (ETDEWEB)

    Matoori, Simon [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Clinic St. Anna, Clinical Research Group, Lucerne (Switzerland); Froehlich, Johannes M. [Hirslanden Clinic St. Anna, Clinical Research Group, Lucerne (Switzerland); ETH Zurich, Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Zurich (Switzerland); Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland); Breitenstein, Stefan [Cantonal Hospital Winterthur, Department of Surgery, Clinic for Visceral and Thoracic Surgery, Winterthur (Switzerland); Doert, Aleksis [Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland); Pozdniakova, Viktoria [Stavanger University Hospital, Department of Radiology, Stavanger (Norway); Koh, Dow-Mu [Royal Marsden Hospital, Department of Radiology, Surrey, England (United Kingdom); Gutzeit, Andreas [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Clinic St. Anna, Clinical Research Group, Lucerne (Switzerland); Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland)

    2016-06-15

    To identify correlations of signal enhancements (SE) and SE normalized to reference tissues of the spleen, kidney, liver, musculus erector spinae (MES) and ductus hepatocholedochus (DHC) on hepatobiliary phase gadoxetate-enhanced MRI with patient age in non-cirrhotic patients. A heterogeneous cohort of 131 patients with different clinical backgrounds underwent a standardized 3.0-T gadoxetate-enhanced liver MRI between November 2008 and June 2013. After exclusion of cirrhotic patients, a cohort of 75 patients with no diagnosed diffuse liver disease was selected. The ratio of signal intensity 20 min post- to pre-contrast administration (SE) in the spleen, kidney, liver, MES and DHC, and the SE of the kidney, liver and DHC normalized to the reference tissues spleen or MES were compared to patient age. Patient age was inversely correlated with the liver SE normalized to the spleen and MES SE (both p < 0.001) and proportionally with the SE of the spleen (p = 0.043), the MES (p = 0.030) and the kidney (p = 0.022). No significant correlations were observed for the DHC (p = 0.347) and liver SE (p = 0.606). The age dependence of hepatic SE normalized to the enhancement in the spleen and MES calls for a cautious interpretation of these quantification methods. (orig.)

  13. Evaluation of dynamic contrast-enhanced T1-weighted perfusion MRI in the differentiation of tumor recurrence from radiation necrosis

    DEFF Research Database (Denmark)

    Larsen, Anne Vibeke Andrée; Simonsen, Helle J; Law, Ian

    2013-01-01

    INTRODUCTION: To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate radiation necrosis from tumor recurrence in patients with high-grade glioma. METHODS: The study was approved by the institutional review board...... and informed consent was obtained from all subjects. 19 patients were recruited following surgery and radiation therapy for glioma. Patients had contrast enhancing lesions, which during the standard MRI examination could not be exclusively determined as recurrence or radiation necrosis. DCE-MRI was used......-MRI may predict the status of contrast enhancing lesions and give results very similar to FDG-PET with regards to differentiation between tumor recurrence and radiation necrosis....

  14. Dynamic contrast enhanced T1 MRI perfusion differentiates pseudoprogression from recurrent glioblastoma.

    Science.gov (United States)

    Thomas, Alissa A; Arevalo-Perez, Julio; Kaley, Thomas; Lyo, John; Peck, Kyung K; Shi, Weiji; Zhang, Zhigang; Young, Robert J

    2015-10-01

    Pseudoprogression may present as transient new or increasing enhancing lesions that mimic recurrent tumors in treated glioblastoma. The purpose of this study was to examine the utility of dynamic contrast enhanced T1 magnetic resonance imaging (DCE MRI) in differentiating between pseudoprogression and tumor progression and devise a cut-off value sensitive for pseudoprogression. We retrospectively examined 37 patients with glioblastoma treated with radiation and temozolomide after surgical resection that then developed new or increasing enhancing lesion(s) indeterminate for pseudoprogression versus progression. Volumetric plasma volume (Vp) and time-dependent leakage constant (Ktrans) maps were measured for the enhancing lesion and the mean and ninetieth percentile histogram values recorded. Lesion outcome was determined by clinical follow up with pseudoprogression defined as stable disease not requiring new treatment. Statistical analysis was performed with Wilcoxon rank-sum tests. Patients with pseudoprogression (n = 13) had Vp (mean) = 2.4 and Vp (90 %tile) = 3.2; and Ktrans (mean) = 3.5 and Ktrans (90 %tile) = 4.2. Patients with tumor progression (n = 24) had Vp (mean) = 5.3 and Vp (90 %tile) = 6.6; and Ktrans (mean) = 7.4 and Ktrans (90 %tile) = 9.1. Compared with tumor progression, pseudoprogression demonstrated lower Vp perfusion values (p = 0.0002) with a Vp (mean) cutoff mean) of >3.6 had a 69% sensitivity and 79% specificity for disease progression. DCE MRI shows lower plasma volume and time dependent leakage constant values in pseudoprogression than in tumor progression. A cut-off value with high sensitivity for pseudoprogression can be applied to aid in interpretation of DCE MRI.

  15. A fully automated system for quantification of background parenchymal enhancement in breast DCE-MRI

    Science.gov (United States)

    Ufuk Dalmiş, Mehmet; Gubern-Mérida, Albert; Borelli, Cristina; Vreemann, Suzan; Mann, Ritse M.; Karssemeijer, Nico

    2016-03-01

    Background parenchymal enhancement (BPE) observed in breast dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been identified as an important biomarker associated with risk for developing breast cancer. In this study, we present a fully automated framework for quantification of BPE. We initially segmented fibroglandular tissue (FGT) of the breasts using an improved version of an existing method. Subsequently, we computed BPEabs (volume of the enhancing tissue), BPErf (BPEabs divided by FGT volume) and BPErb (BPEabs divided by breast volume), using different relative enhancement threshold values between 1% and 100%. To evaluate and compare the previous and improved FGT segmentation methods, we used 20 breast DCE-MRI scans and we computed Dice similarity coefficient (DSC) values with respect to manual segmentations. For evaluation of the BPE quantification, we used a dataset of 95 breast DCE-MRI scans. Two radiologists, in individual reading sessions, visually analyzed the dataset and categorized each breast into minimal, mild, moderate and marked BPE. To measure the correlation between automated BPE values to the radiologists' assessments, we converted these values into ordinal categories and we used Spearman's rho as a measure of correlation. According to our results, the new segmentation method obtained an average DSC of 0.81 0.09, which was significantly higher (p<0.001) compared to the previous method (0.76 0.10). The highest correlation values between automated BPE categories and radiologists' assessments were obtained with the BPErf measurement (r=0.55, r=0.49, p<0.001 for both), while the correlation between the scores given by the two radiologists was 0.82 (p<0.001). The presented framework can be used to systematically investigate the correlation between BPE and risk in large screening cohorts.

  16. Detection of parenchymal abnormalities in experimentally induced acute pyelonephritis in rabbits using contrast-enhanced ultrasonography, CT, and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Jeong Ah; Kim, Bo Hyun; Kim, Seung Kwon; Seo, Jin Won [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Jong Sung [Laboratory Animal Research Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-12-15

    We evaluated the efficacy of contrast-enhanced ultrasonography (CEUS) in detecting acute pyelonephritis (APN) using the rabbit kidney model and compared it with CT and MRI. This study was approved by the Institutional Review Board. In a total of 20 New Zealand White rabbits, APN was induced experimentally. CEUS, CT, and MRI were performed on the first, third, and seventh postoperative days. After imaging studies, the subjects were sacrificed and the pathological diagnosis of APN was confirmed in each animal by a pathologist. Imaging studies were obtained in eight animals, including eight CEUS, four computed tomography (CT), and four magnetic resonance imaging (MRI) images. CEUS depicted diffuse renal enlargement (7), diffuse heterogeneous parenchymal enhancement (6), and focal areas of decreased parenchymal enhancement (6). These findings were well correlated with the CT and MRI findings in five cases in which these studies were available. CT and MRI showed diffuse renal enlargement, diffuse heterogeneous parenchymal enhancement, focal areas of decreased parenchymal enhancement, focal contour bulging, and the finding of perinephric spread of infection. In a rabbit model, CEUS could depict the parenchymal lesions of APN similar to CT or MRI; however, it was limited in depicting the perinephric extension of inflammation.

  17. The Added Diagnostic Value of Dynamic Contrast-Enhanced MRI at 3.0 T in Nonpalpable Breast Lesions

    Science.gov (United States)

    Merckel, Laura G.; Verkooijen, Helena M.; Peters, Nicky H. G. M.; Mann, Ritse M.; Veldhuis, Wouter B.; Storm, Remmert K.; Weits, Teun; Duvivier, Katya M.; van Dalen, Thijs; Mali, Willem P. Th. M.; Peeters, Petra H. M.; van den Bosch, Maurice A. A. J.

    2014-01-01

    Objective To investigate the added diagnostic value of 3.0 Tesla breast MRI over conventional breast imaging in the diagnosis of in situ and invasive breast cancer and to explore the role of routine versus expert reading. Materials and Methods We evaluated MRI scans of patients with nonpalpable BI-RADS 3–5 lesions who underwent dynamic contrast-enhanced 3.0 Tesla breast MRI. Initially, MRI scans were read by radiologists in a routine clinical setting. All histologically confirmed index lesions were re-evaluated by two dedicated breast radiologists. Sensitivity and specificity for the three MRI readings were determined, and the diagnostic value of breast MRI in addition to conventional imaging was assessed. Interobserver reliability between the three readings was evaluated. Results MRI examinations of 207 patients were analyzed. Seventy-eight of 207 (37.7%) patients had a malignant lesion, of which 33 (42.3%) patients had pure DCIS and 45 (57.7%) invasive breast cancer. Sensitivity of breast MRI was 66.7% during routine, and 89.3% and 94.7% during expert reading. Specificity was 77.5% in the routine setting, and 61.0% and 33.3% during expert reading. In the routine setting, MRI provided additional diagnostic information over clinical information and conventional imaging, as the Area Under the ROC Curve increased from 0.76 to 0.81. Expert MRI reading was associated with a stronger improvement of the AUC to 0.87. Interobserver reliability between the three MRI readings was fair and moderate. Conclusions 3.0 T breast MRI of nonpalpable breast lesions is of added diagnostic value for the diagnosis of in situ and invasive breast cancer. PMID:24713637

  18. The added diagnostic value of dynamic contrast-enhanced MRI at 3.0 T in nonpalpable breast lesions.

    Directory of Open Access Journals (Sweden)

    Laura G Merckel

    Full Text Available OBJECTIVE: To investigate the added diagnostic value of 3.0 Tesla breast MRI over conventional breast imaging in the diagnosis of in situ and invasive breast cancer and to explore the role of routine versus expert reading. MATERIALS AND METHODS: We evaluated MRI scans of patients with nonpalpable BI-RADS 3-5 lesions who underwent dynamic contrast-enhanced 3.0 Tesla breast MRI. Initially, MRI scans were read by radiologists in a routine clinical setting. All histologically confirmed index lesions were re-evaluated by two dedicated breast radiologists. Sensitivity and specificity for the three MRI readings were determined, and the diagnostic value of breast MRI in addition to conventional imaging was assessed. Interobserver reliability between the three readings was evaluated. RESULTS: MRI examinations of 207 patients were analyzed. Seventy-eight of 207 (37.7% patients had a malignant lesion, of which 33 (42.3% patients had pure DCIS and 45 (57.7% invasive breast cancer. Sensitivity of breast MRI was 66.7% during routine, and 89.3% and 94.7% during expert reading. Specificity was 77.5% in the routine setting, and 61.0% and 33.3% during expert reading. In the routine setting, MRI provided additional diagnostic information over clinical information and conventional imaging, as the Area Under the ROC Curve increased from 0.76 to 0.81. Expert MRI reading was associated with a stronger improvement of the AUC to 0.87. Interobserver reliability between the three MRI readings was fair and moderate. CONCLUSIONS: 3.0 T breast MRI of nonpalpable breast lesions is of added diagnostic value for the diagnosis of in situ and invasive breast cancer.

  19. Dynamic enhanced MRI of the subacromial bursa: correlation with arthroscopic and histological findings

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, S. [Dept. of Radiology, Osaka Kosei-nenkin Hospital (Japan); Yoneda, M. [Shoulder and Sports Medicine Service, Osaka Kosei-nenkin Hospital, Osaka City, Osaka (Japan); Kobayashi, Y. [Dept. of Pathology, Osaka Kosei-nenkin Hospital (Japan); Fukushima, S. [Dept. of Orthopaedic Surgery, Sapporo Tokeidai Hospital, Osaka (Japan); Wakitani, S. [Dept. of Orthopaedic Surgery, Shinsyu Univ., Matsumato (Japan)

    2003-09-01

    Objective: To assess dynamic MRI with Gd-DTPA enhancement for evaluating inflammatory changes in the subacromial bursa. Design and patients: We detected the signal intensity changes in dynamic MRI of the subacromial bursa, and confirmed these macroscopically by arthroscopy and histologically. The signal intensity was measured using built-in software, and the enhancement ratio (E ratio) was calculated from dynamic MR images. In addition, as a parameter of the rate of the increase in the signal intensity from 0 to 80 s, the mean increase per second in the E ratio was obtained as the coefficient of enhancement (CE). The correlation was studied of the E ratio and CE with the arthroscopic findings (redness, villous formation, thickening and adhesion), and of the E ratio and CE with the histological findings (capillary proliferation, papillary hyperplasia, fibrosis and inflammatory cell infiltration) of the subacromial bursa. Of patients with shoulder pain, this study included those with rotator cuff injury; patients with rheumatoid arthritis or pitching shoulder disorders were excluded. There were 27 patients (15 men, 12 women) ranging in age from 25 to 73 years (mean 49.1 years). Dynamic MRI of the shoulder was also performed on the healthy side of 10 patients and in five normal young volunteers. Results and conclusions: Changes in signal intensity on dynamic MRI were measured in the subacromial bursa. The E ratio (80 s) and CE (0-80 s) were significantly correlated with redness and villous formation as arthroscopic findings, positively correlated with capillary proliferation and papillary hyperplasia as histological findings (p < 0.05), and negatively correlated with fibrosis as a histological finding (p < 0.05) in the subacromial bursa. The patterns of dynamic curves were well correlated with the bursoscopic and histological findings of the synovium of the subacromial bursa. Dynamic MRI appears to correlate with inflammatory activity of synovium of the subacromial

  20. Does the degree of background enhancement in breast MRI affect the detection and staging of breast cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Uematsu, Takayoshi [Shizuoka Cancer Center Hospital, Breast Imaging and Breast Intervention Section, Shizuoka (Japan); Kasami, Masako [Shizuoka Cancer Center Hospital, Department of Pathology, Naga-izumi, Shizuoka (Japan); Watanabe, Junichiro [Shizuoka Cancer Center Hospital, Division of Medical Oncology, Naga-izumi, Shizuoka (Japan)

    2011-11-15

    The purpose of this study was to assess the influence of background enhancement on the detection and staging of breast cancer using MRI as an adjunct to mammography or ultrasound. One hundred forty-six bilateral breast MRI examinations were evaluated to assess the extent of a known primary tumour and to problem solve after mammography or ultrasound without adjusting for the phase in the patients' menstrual cycle. The background enhancement was classified into four categories by visual evaluation: minimal, mild, moderate and marked. In total, 131 histologically confirmed abnormal cases (104 malignant and 27 benign) and 15 normal cases were included in the analysis. There was no tumour size-related bias between the groups (p = 0.522). For the primary index tumour, the sensitivities of MRI with minimal/mild and moderate/marked background enhancement were 100% and 76% (p = 0.001), respectively. Thus, the degree of background enhancement did not affect the specificity. For evaluating tumour extent (n = 104), the accuracy of MRI with moderate/marked background enhancement (52%) was significantly lower than that with minimal/mild background enhancement (84%; p = 0.002). The degree of background enhancement affected the detection and staging of breast cancer using MRI. (orig.)

  1. Noninvasive detection of cardiac amyloidosis using delayed enhanced MDCT: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Deux, Jean-Francois [University Paris Est Creteil, Assistance Publique-Hopitaux de Paris, Cardiac MR Unit, Radiology Department, Henri Mondor Hospital, Creteil (France); University Paris Est Creteil, Assistance Publique-Hopitaux de Paris, CNRS EAC 4396, Centre de Recherches Chirurgicales, Henri Mondor Hospital, Creteil (France); Reseau Amylose Mondorien, Henri Mondor Hospital, Creteil (France); Mihalache, Cristian-Ionut; Legou, Francois; Luciani, Alain; Kobeiter, Hicham; Rahmouni, Alain [University Paris Est Creteil, Assistance Publique-Hopitaux de Paris, Cardiac MR Unit, Radiology Department, Henri Mondor Hospital, Creteil (France); Damy, Thibaud [Reseau Amylose Mondorien, Henri Mondor Hospital, Creteil (France); University Paris Est Creteil, Assistance Publique-Hopitaux de Paris, Cardiology Department, Henri Mondor Hospital, Creteil (France); Mayer, Julie [University Paris Est Creteil, Assistance Publique-Hopitaux de Paris, Cardiac MR Unit, Radiology Department, Henri Mondor Hospital, Creteil (France); Reseau Amylose Mondorien, Henri Mondor Hospital, Creteil (France); Rappeneau, Stephane [Reseau Amylose Mondorien, Henri Mondor Hospital, Creteil (France); Plante-Bordeneuve, Violaine [Reseau Amylose Mondorien, Henri Mondor Hospital, Creteil (France); University Paris Est Creteil, Assistance Publique-Hopitaux de Paris, Department of Neurophysiology of Neurology, Henri Mondor Hospital, Creteil (France)

    2015-08-15

    To evaluate myocardial enhancement of patients with cardiac amyloidosis (CA) using computed tomography (CT). Thirteen patients with CA and 11 control patients were examined with first-pass and delayed CT acquisition. A qualitative and quantitative analysis of images was performed. Myocardial attenuation, myocardial signal-to-noise ratio (SNR{sub myoc}), blood pool SNR (SNR{sub blood}), contrast-to-noise ratio between blood pool and myocardium (CNR{sub blood-myoc}) and relative attenuation index (RAI) defined as variation of myocardial attenuation between delayed and first-pass acquisitions were calculated. Two false negative cases (15 %) and three false positive cases (27 %) were detected on qualitative analysis. SNR{sub myoc} of patients with CA was significantly (p < 0.05) lower on first-pass (4.08 ± 1.9) and higher on delayed acquisition (7.10 ± 2.7) than control patients (6.1 ± 2.2 and 5.03 ± 1.8, respectively). Myocardial attenuation was higher in CA (121 ± 39 HU) than control patients (81 ± 17 HU) on delayed acquisition. CNR{sub blood-myoc} was significantly (p < 0.05) lower in CA (1.51 ± 0.7) than control patients (2.85 ± 1.2) on delayed acquisition. The RAI was significantly (p < 0.05) higher in CA (0.12 ± 0.25) than in control patients (-0.56 ± 0.21). Dual phase MDCT can detect abnormal myocardial enhancement in patients with CA. (orig.)

  2. LHRH-functionalized superparamagnetic iron oxide nanoparticles for breast cancer targeting and contrast enhancement in MRI

    Energy Technology Data Exchange (ETDEWEB)

    Meng, J.; Fan, J. [Princeton Institute of Science and Technology of Materials and the Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Galiana, G. [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Branca, R.T. [Department of Chemistry, Duke University, Durham, NC 27708-0354 (United States); Clasen, P.L.; Ma, S. [Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, PA 18015-3195 (United States); Zhou, J. [Princeton Institute of Science and Technology of Materials and the Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Leuschner, C. [Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808 (United States); Kumar, C.S.S.R.; Hormes, J. [Center for Advanced Microstructures and Devices, Louisiana State University, 6980 Jefferson Hwy, Baton Rouge, LA 70806 (United States); Otiti, T. [Department of Physics, Makerere University, Kampala (Uganda); Beye, A.C. [Department of Physics, Cheikh Anta Diop University, Dakar (Senegal); Harmer, M.P.; Kiely, C.J. [Center for Advanced Materials and Nanotechnology, Lehigh University, Bethlehem, PA 18015-3195 (United States); Warren, W. [Department of Chemistry, Duke University, Durham, NC 27708-0354 (United States); Haataja, M.P. [Princeton Institute of Science and Technology of Materials and the Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Soboyejo, W.O., E-mail: soboyejo@princeton.edu [Princeton Institute of Science and Technology of Materials and the Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2009-05-05

    This paper shows that superparamagnetic iron oxide nanoparticles (SPIONs) conjugated to luteinizing hormone releasing hormone (LHRH) (LHRH-SPIONs), can be used to target breast cancer cells. They also act as contrast enhancement agents during the magnetic resonance imaging of breast cancer xenografts. A combination of transmission electron microscopy (TEM) and spectrophotometric analysis was used in our experiments, to investigate the specific accumulation of the functionalized superparamagnetic iron oxide nanoparticles (SPIONs) in cancer cells. The contrast enhancement of conventional T2 images obtained from the tumor tissue and of breast cancer xenograft bearing mice is shown to be much greater than that in saline controls, when the tissues were injected with LHRH-SPIONs. Magnetic anisotropy multi-CRAZED images of tissues extracted from mice injected with SPIONs were also found to have enhanced MRI contrast in breast cancer xenografts and metastases in the lungs.

  3. Contribution of diffusion-weighted imaging to dynamic contrast-enhanced MRI in the characterization of papillary breast lesions.

    Science.gov (United States)

    Yildiz, Seyma; Toprak, Huseyin; Ersoy, Yeliz Emine; Malya, Fatma Ümit; Bakan, Ayşe Ahsen; Aralaşmak, Ayşe; Gucin, Zuhal

    2017-08-01

    Papillary lesions have a broad spectrum of appearances on magnetic resonance imaging (MRI). The purpose of this study was to evaluate whether apparent diffusion coefficient (ADC) values of papillary lesions can be used to characterize lesion as benign or malignant. This retrospective study included 29 papillary lesions. Diagnostic values of dynamic contrast-enhanced MRI (DCE-MRI), DWI-ADC, and DCE-MRI plus DWI-ADC were separately calculated. The malignant papillary lesions (0.744×10(-3)  mm(2) /s) exhibited significantly lower mean ADC values than the benign lesions (1.339×10(-3)  mm(2) /s). Addition of DWI to standard DCE-MRI provided 100% sensitivity. We hypothesized that this combination may prevent unnecessary excisional biopsies. © 2017 Wiley Periodicals, Inc.

  4. Prostate dynamic contrast-enhanced MRI with simple visual diagnostic criteria: is it reasonable?

    Energy Technology Data Exchange (ETDEWEB)

    Girouin, Nicolas; Tonina Senes, Alejandro [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Mege-Lechevallier, Florence [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Histopathology, Lyon (France); Bissery, Alvine; Rabilloud, Muriel [Department of Biostatistics, Hospices Civils de Lyon, Lyon (France); Lyon, F-69003, France; Universite de Lyon 1, Laboratoire Biostatistiques-Sante, Universite de Lyon, Pierre-Benite (France); Marechal, Jean-Marie [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Colombel, Marc [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Lyon, F-69003, France; Universite de Lyon 1, Faculte de Medecine Lyon Nord, Universite de Lyon, Lyon (France); Lyonnet, Denis; Rouviere, Olivier [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Lyon, F-69003, France; Universite de Lyon 1, Faculte de Medecine Lyon Nord, Universite de Lyon, Lyon (France); Inserm, U556, Lyon (France)

    2007-06-15

    The purpose of this study was to evaluate the accuracy of prostate cancer localization with simple visual diagnostic criteria using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). A total of 46 consecutive patients with biopsy-proven prostate cancer underwent prostate 1.5 T MRI with pelvic phased-array coils before prostatectomy. Besides the usual T2-weighted sequences, a 30-s DCE sequence was acquired three times after gadoterate injection. On DCE images, all early enhancing lesions of the peripheral zone were considered malignant. In the central gland, only early enhancing lesions appearing homogeneous or invading the peripheral zone were considered malignant. Three readers specified the presence of cancer in 20 prostate sectors and the location of distinct tumors. Results were compared with histology; p < 0.05 was considered significant. For localization of cancer in the sectors, DCE imaging had a significantly higher sensitivity [logistic regression, odds ratio (OR): 3.9, p < 0.0001] and a slightly but significantly lower specificity (OR: 0.57, p < 0.0001). Of the tumors >0.3 cc, 50-60% and 78-81% were correctly depicted with T2-weighted and DCE imaging, respectively. For both techniques, the depiction rate of tumors >0.3 cc was significantly influenced by the Gleason score (most Gleason {<=}6 tumors were overlooked), but not by the tumor volume. DCE-MRI using pelvic phased-array coils and simple visual diagnostic criteria is more sensitive for tumor localization than T2-weighted imaging. (orig.)

  5. Background parenchymal enhancement in breast MRI before and after neoadjuvant chemotherapy: correlation with tumour response

    Energy Technology Data Exchange (ETDEWEB)

    Preibsch, H.; Wanner, L.; Bahrs, S.D.; Wietek, B.M.; Nikolaou, K.; Wiesinger, B. [University Hospital Tuebingen, Diagnostic and Interventional Radiology, Tuebingen (Germany); Siegmann-Luz, K.C. [Diagnostic Center for Breast Cancer and Screening Mammography Brandenburg Ost, Koenigs Wusterhausen (Germany); Oberlecher, E.; Hahn, M. [University Hospital Tuebingen, Department of Gynecology and Obstetrics, Tuebingen (Germany); Staebler, A. [University Hospital Tuebingen, Institute of Pathology and Neuropathology, Tuebingen (Germany)

    2016-06-15

    To correlate the decrease in background parenchymal enhancement (BPE) and tumour response measured with MRI in breast cancer patients treated with neoadjuvant chemotherapy (NAC). One hundred and forty-six MRI examinations of 73 patients with 80 biopsy-proven breast cancers who underwent breast MRI before and after NAC were retrospectively analysed. All images were reviewed by two blinded readers, who classified BPE into categories (BEC; 1 = minimal, 2 = mild, 3 = moderate, 4 = marked) before and after NAC. Histopathological and morphological tumour responses were analysed and compared. The distribution of BEC 1/2/3/4 was 25/46/18/11 % before and 78/20/2/0 % after NAC. On average, BPE decreased by 0.87 BEC. Cohen's kappa showed substantial agreement (k = 0.73-0.77) before and moderate agreement (k = 0.43-0.60) after NAC and moderate agreement (k = 0.62-0.60) concerning the change in BEC. Correlating the change in BPE with tumour response, the average decrease in BEC was 1.3 in cases of complete remission, 0.83 in cases with partial response, 0.85 in cases with stable disease and 0.40 in cases with progressive disease. Correlation analysis showed a significant correlation between the decrease in BEC and tumour response (r = -0.24, p = 0.03). BPE decreased by, on average, 0.87 BEC following NAC for breast cancer. The degree of BPE reduction seemed to correlate with tumour response. (orig.)

  6. Alterations in renal morphology and function after ESWL therapy: evaluation with dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Krestin, G.P. [Dept. of Medical Radiology, University Hospital Zurich (Switzerland); Fischbach, R. [Dept. of Radiology, Univ. of Cologne (Germany); Vorreuther, R. [Dept. of Urology, Univ. of Cologne (Germany); Schulthess, G.K. von [Dept. of Medical Radiology, University Hospital Zurich (Switzerland)

    1993-06-01

    Contrast-enhanced gradient-echo MRI was used to evaluate morphological and functional alterations in the kidneys after extracorporeal shock wave lithotripsy (ESWL). Dynamic MRI with a temporal resolution of 10 s per image was performed by repeated imaging in the coronal plane after administration of gadolinium-DTPA (0.1 mmol/kg) before and after ESWL for renal calculi in 25 patients. Before ESWL 22 patients had normally functioning kidneys, characterised by a marked decrease in signal intensity in the renal medulla 30-40 s after the onset of cortical perfusion. After ESWL 8 patients had functional abnormalities: in 2 cases the medullary signal decrease was disturbed throughout the whole organ, while 6 kidneys demonstrated regional loss of concentrating ability in the medulla. Morphological alterations (oedema with blurred contours and loss of corticomedullary differentiation; parenchymal haemorrhage and haemorrhage in a cortical cyst; subcapsular, perirenal and pararenal haematoma) were detected in 9 cases. Haemorrhage was encountered more often after administration of more than 2500 shock waves; however, no such correlation was seen in the kidneys with functional disturbances following ESWL therapy. MRI proved to be a sensitive method for the assessment of morphological and functional alterations after ESWL, but longer follow-up studies are required to identify the clinical impact of these early changes. (orig.)

  7. Semi-quantitative assessment of pulmonary perfusion in children using dynamic contrast-enhanced MRI

    Science.gov (United States)

    Fetita, Catalin; Thong, William E.; Ou, Phalla

    2013-03-01

    This paper addresses the study of semi-quantitative assessment of pulmonary perfusion acquired from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in a study population mainly composed of children with pulmonary malformations. The automatic analysis approach proposed is based on the indicator-dilution theory introduced in 1954. First, a robust method is developed to segment the pulmonary artery and the lungs from anatomical MRI data, exploiting 2D and 3D mathematical morphology operators. Second, the time-dependent contrast signal of the lung regions is deconvolved by the arterial input function for the assessment of the local hemodynamic system parameters, ie. mean transit time, pulmonary blood volume and pulmonary blood flow. The discrete deconvolution method implements here a truncated singular value decomposition (tSVD) method. Parametric images for the entire lungs are generated as additional elements for diagnosis and quantitative follow-up. The preliminary results attest the feasibility of perfusion quantification in pulmonary DCE-MRI and open an interesting alternative to scintigraphy for this type of evaluation, to be considered at least as a preliminary decision in the diagnostic due to the large availability of the technique and to the non-invasive aspects.

  8. Brain-wide pathway for waste clearance captured by contrast-enhanced MRI.

    Science.gov (United States)

    Iliff, Jeffrey J; Lee, Hedok; Yu, Mei; Feng, Tian; Logan, Jean; Nedergaard, Maiken; Benveniste, Helene

    2013-03-01

    The glymphatic system is a recently defined brain-wide paravascular pathway for cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange that facilitates efficient clearance of solutes and waste from the brain. CSF enters the brain along para-arterial channels to exchange with ISF, which is in turn cleared from the brain along para-venous pathways. Because soluble amyloid β clearance depends on glymphatic pathway function, we proposed that failure of this clearance system contributes to amyloid plaque deposition and Alzheimer's disease progression. Here we provide proof of concept that glymphatic pathway function can be measured using a clinically relevant imaging technique. Dynamic contrast-enhanced MRI was used to visualize CSF-ISF exchange across the rat brain following intrathecal paramagnetic contrast agent administration. Key features of glymphatic pathway function were confirmed, including visualization of para-arterial CSF influx and molecular size-dependent CSF-ISF exchange. Whole-brain imaging allowed the identification of two key influx nodes at the pituitary and pineal gland recesses, while dynamic MRI permitted the definition of simple kinetic parameters to characterize glymphatic CSF-ISF exchange and solute clearance from the brain. We propose that this MRI approach may provide the basis for a wholly new strategy to evaluate Alzheimer's disease susceptibility and progression in the live human brain.

  9. Significance of epiphyseal cartilage enhancement defects in pediatric osteomyelitis identified by MRI with surgical correlation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, David P. [Vanderbilt University School of Medicine, Nashville, TN (United States); Hernanz-Schulman, Marta; Kan, J.H. [Vanderbilt Children' s Hospital, Department of Radiology and Radiological Sciences, Nashville, TN (United States); Martus, Jeffrey E.; Lovejoy, Steven A. [Vanderbilt Children' s Hospital, Division of Pediatric Orthopaedics, Nashville, TN (United States); Yu, Chang [Vanderbilt University, Department of Biostatistics, Nashville, TN (United States)

    2011-03-15

    Epiphyseal cartilage enhancement defects (ED) may occur in the setting of epiphyseal osteomyelitis (OM), and its significance is uncertain. The aim of this study is to evaluate the incidence and clinical impact of epiphyseal cartilage ED in pediatric epiphyseal OM. The 13 children involved in this retrospective review were younger than 6 years of age and diagnosed with OM. They underwent contrast-enhanced MRI and surgical exploration yielding 14 study epiphyses. Seventeen age-matched children without evidence of infection who underwent contrast-enhanced MRI in the same period yielded 28 control epiphyses. Images were reviewed for focal/global ED, correlated with cartilage abscesses and compared with surgical reports. Study and control ED were respectively present in 10/14 (71.4% - 6 global, 4 focal) and 6/28 (21.4% - 0 global, 6 focal), P = 0.0017. An analysis of ED patterns between study and control patients showed significant difference for global (P = 0.0006), but no difference for focal ED (P = 0.71). For the six study epiphyses with global ED, epiphyseal abscesses were present in two (33.3%). For the four study epiphyses with focal ED, epiphyseal abscesses were present in two (50%). For the controls, no abnormalities were found on follow-up of epiphyses with focal ED. ED are seen normally but more commonly in children with OM. ED should not be confused with epiphyseal abscesses. (orig.)

  10. Utility of Gd-EOB-DTPA-Enhanced MRI in Diagnosing Small Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Soo Ryang Kim

    2009-07-01

    Full Text Available We describe an 8-mm hepatocellular carcinoma (HCC with hepatitis C virus-related cirrhosis in a 74-year-old woman. Ultrasound (US revealed an 8-mm hyperechoic nodule in segment 6 of the liver. Contrast-enhanced computed tomography (CT and US revealed no hypervascularity in the early phase and no washout in the late phase and the Kupffer phase, respectively. CT during arteriography revealed no hypervascularity and CT during arterial portography disclosed no perfusion defect. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI revealed no hypervascularity in the early phase, but disclosed a defect in the hepatobiliary phase. Histologically, the nodule was diagnosed as well-differentiated HCC characterized by more than two-fold the cellularity of the non-tumorous area, with a high nuclear:cytoplasmic ratio, increased cytoplasmic eosinophilia, fatty change, and slight cell atypia with an irregular thin trabecular pattern. Our case demonstrates the utility of Gd-EOB-DTPA-enhanced MRI in the diagnosis of small HCC.

  11. Observer-based predictive controller design with network-enhanced time-delay compensation

    Science.gov (United States)

    Florin Caruntu, Constantin

    2015-02-01

    State feedback control is very attractive due to the precise computation of the gain matrix, but the implementation of a state feedback controller is possible only when all state variables are directly measurable. This condition is almost impossible to accomplish due to the excess number of required sensors or unavailability of states for measurement in most of the practical situations. Hence, the need for an estimator or observer is obvious to estimate all the state variables by observing the input and the output of the controlled system. As such, the goal of this paper is to provide a control design methodology based on a Luenberger observer design that can assure the closed-loop performances of a vehicle drivetrain with backlash, while compensating the network-enhanced time-varying delays. This goal is achieved in a sequential manner: firstly, a piecewise linear model of two inertias drivetrain, which takes into consideration the backlash nonlinearity and the network-enhanced time-varying delay effects is derived; then, a Luenberger observer which estimates the state variables is synthesized and the robust full state-feedback predictive controller based on flexible control Lyapunov functions is designed to explicitly take into account the bounds of the disturbances caused by time-varying delays and to guarantee also the input-to-state stability of the system in a non-conservative way. The full state-feedback predictive control strategy based on the Luenberger observer design was experimentally tested on a vehicle drivetrain emulator controlled through controller area network, with the aim of minimizing the backlash effects while compensating the network-enhanced delays.

  12. Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI

    Science.gov (United States)

    Sreeja, V.; Jayaprabha, K. N.; Joy, P. A.

    2015-04-01

    Superparamagnetic iron oxide nanoparticles of size ~5 nm surface functionalized with ascorbic acid (vitamin C) form a stable dispersion in water with a hydrodynamic size of ~30 nm. The anti-oxidant property of ascorbic acid is retained after capping, as evidenced from the capability of converting methylene blue to its reduced leuco form. NMR relaxivity studies show that the ascorbic-acid-coated superparamagnetic iron oxide aqueous nanofluid is suitable as a contrast enhancement agent for MRI applications, coupled with the excellent biocompatibility and medicinal values of ascorbic acid.

  13. Vascular changes caused by deep brain stimulation using double-dose gadolinium-enhanced brain MRI

    Institute of Scientific and Technical Information of China (English)

    Byeong Sam Choi; Yong Hwan Kim; Sang Ryong Jeon

    2014-01-01

    We retrospectively analyzed the clinical data of 32 patients with medically intractable idiopathic Parkinson’s disease who had undergone staged bilateral deep brain stimulation of the subtha-lamic nuclei from January 2007 to May 2011. The vascularture of the patients who received two deep brain stimulations was detected using double-dose gadolinium-enhanced brain MRI. The dimensions of straight sinus, superior sagittal sinus, ipsilateral internal cerebral vein in the tha-lamic branch and ipsilateral anterior caudate vein were reduced. These ifndings demonstrate that bilateral deep brain stimulation of the subthalamic nuclei affects cerebral venous blood lfow.

  14. Detection of cranial meningiomas: comparison of {sup 68}Ga-DOTATOC PET/CT and contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Afshar-Oromieh, Ali; Giesel, Frederik L.; Haberkorn, Uwe; Haufe, Sabine; Kratochwil, Clemens [University Hospital of Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); Linhart, Heinz G. [DKFZ, National Center for Tumor Diseases (NCT), Heidelberg (Germany); Combs, Stephanie E. [University Hospital of Heidelberg, Department of Radiation Oncology and Therapy, Heidelberg (Germany); Podlesek, Dino [University Hospital of Dresden, Department of Neurosurgery, Dresden (Germany); Eisenhut, Michael [DKFZ, Department of Radiopharmacy, Heidelberg (Germany)

    2012-09-15

    PET imaging with somatostatin receptor ligands, such as {sup 68}Ga-DOTATOC, is a well-established method for detection and target volume definition of meningiomas prior to radiotherapy. Since DOTATOC PET delivers a higher contrast between meningiomas and surrounding tissues than MRI, we conducted a retrospective analysis to compare the diagnostic accuracy of contrast-enhanced MRI (CE-MRI) with {sup 68}Ga-DOTATOC PET/CT in patients with cranial meningiomas prior to radiotherapy. Over a period of 6 years, 134 patients (20-82 years of age, 107 women and 27 men) underwent cranial CE-MRI and {sup 68}Ga-DOTATOC PET/CT. To compare the two methods, the lesions considered typical of meningiomas visually were counted and analysed with respect to their location and SUVmax. In the 134 patients investigated by both modalities, 190 meningiomas were detected by {sup 68}Ga-DOTATOC PET/CT and 171 by CE-MRI. With knowledge of the PET/CT data, the MRI scans were reinvestigated, which led to the detection of 4 of the 19 incidental meningiomas, resulting in an overall detection rate of 92 % of the meningioma lesions that were found by PET/CT. Ga-DOTATOC PET/CT demonstrated an improved sensitivity in meningioma detection when compared to CE-MRI. Tumours adjacent to the falx cerebri, located at the skull base or obscured by imaging artefacts or calcification are particularly difficult to detect by MRI. Therefore {sup 68}Ga-DOTATOC PET/CT may provide additional information in patients with uncertain or equivocal results on MRI or could help to confirm a diagnosis of meningioma based on MRI or could help to confirm MRI-based diagnosis of meningiomas in cases of biopsy limitations. It is possible that not only radiotherapy and surgical planning, but also follow-up strategies would benefit from this imaging modality. (orig.)

  15. Enhanced washout of {sup 99m}Tc-tetrofosmin in hypertrophic cardiomyopathy: quantitative comparisons with regional {sup 123}I-BMIPP uptake and wall thickness determined by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Thet-Thet-Lwin, Tohoru; Takeda, Jin; Wu, Yuko; Fumikura, Keiji; Iida, Satoru; Kawano, Iwao; Yamaguchi, Yuji; Itai [Institute of Clinical Medicine, University of Tsukuba, Tennodai 1-1-1, 305-8575, Tsukuba-shi, Ibaraki-ken (Japan)

    2003-07-01

    The diagnostic value of technetium-99m tetrofosmin (TF) washout in hypertrophic cardiomyopathy (HCM) was examined by investigating its relation to the metabolic abnormality depicted by iodine-123 {beta}-methyl-p-iodophenylpentadecanoic acid (BMIPP) uptake and the left ventricular (LV) myocardial wall thickness as measured by magnetic resonance imaging (MRI). TF washout was evaluated in 31 patients with HCM and 23 normal control subjects using 30-min (early) and 3-h (delayed) TF single-photon emission tomography images. The LV myocardial wall was divided into 19 segments and the percentage TF washout, regional BMIPP uptake and LV wall thickness were measured in each segment. Mean TF washout in the patients with HCM was significantly faster than that in normal control subjects (23.7{+-}5.7 vs 13.4{+-}4.1, P<0.0001). In the patients with HCM, TF washout showed an excellent correlation with MRI wall thickness (r=0.82, P<0.0001) and a good inverse correlation with regional BMIPP uptake (r=-0.72, P<0.0001). In addition, a good linear correlation was observed between TF uptake and MRI wall thickness in the 19 regional segments. In conclusion, the degree of TF washout corresponds well with the severity of myocardial wall thickness and the degree of metabolic abnormality in patients with HCM. These results suggest that enhanced TF washout might provide additional clinical information regarding metabolic alterations in HCM. (orig.)

  16. Delayed-enhancement magnetic resonance imaging at 3.0 T using 0.15 mmol/kg of contrast agent for the assessment of chronic myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jun, E-mail: yangjunyhd@163.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Ma, Heng, E-mail: mahengyhd@163.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Liu, Jing, E-mail: liujingyhd@163.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Wang, Chunxiao, E-mail: chunxiaoyhd@163.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Shi, Yinghong, E-mail: yinghongyhd@163.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Xie, Haizhu, E-mail: haizhuyhd@163.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Huo, Futao, E-mail: kailinusa@126.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Liu, Fengli, E-mail: fengliyhd@126.com [Yuhuangding Hospital, Yantai, Shandong Province (China); Lin, Kai, E-mail: kai-lin@northwestern.edu [Department of Radiology, Northwestern University, Chicago, IL (United States)

    2014-05-15

    Objective: A recent international, multicenter, double-blinded, randomized trial shows delayed-enhanced magnetic resonance imaging (DE-MRI) using contrast doses of ≥0.2 mmol/kg is effective in the detection and assessment of myocardial infarction (MI), and 0.1 mmol/kg is not enough; intermediate doses between 0.1 and 0.2 mmol/kg have not been tested. The aim of this study was to prospectively test the performance of DE-MRI using 0.15 mmol/kg of contrast agent for the detection of MI. Materials and methods: A total of 31 consecutive patients with chronic MI underwent DE-MRI at 3.0 T using both 0.15 mmol/kg and 0.2 mmol/kg of contrast agent in random order and on separate days. Infarction segment and infarction size were compared on DE-MRI images using a 17-segment model. Bland–Altman analysis was used to analyze correlation and agreement between global infarct sizes. Results: DE-MRI showed enhanced myocardium in all the 31 patients with chronic MI. There was no significant difference between the 0.15 mmol/kg and 0.2 mmol/kg images in all 31 patients based on the infarction segment (7.87 ± 2.72 vs. 7.81 ± 2.64, respectively; p = 0.33). There was no significant difference between the infarction size obtained from 0.15 mmol/kg acquisition and that from 0.2 mmol/kg acquisition (16.3 ± 7.8% vs. 16.4 ± 7.9%, respectively; p = 0.87). A strong correlation between the infarction size obtained from 0.15 mmol/kg acquisition and that from 0.2 mmol/kg acquisition was indicated through Bland–Altman analysis. Conclusion: DE-MRI at 3.0 T using 0.15 mmol/kg of contrast agent is effective for the assessment of MI.

  17. Impact of liver cirrhosis on liver enhancement at Gd-EOB-DTPA enhanced MRI at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Verloh, N., E-mail: niklas.verloh@stud.uni-regensburg.de [Department of Radiology, University Hospital Regensburg, Regensburg (Germany); Haimerl, M.; Rennert, J.; Müller-Wille, R.; Nießen, C. [Department of Radiology, University Hospital Regensburg, Regensburg (Germany); Kirchner, G. [Department of Gastroenterology, University Hospital Regensburg, Regensburg (Germany); Scherer, M.N. [Department of Surgery, University Hospital Regensburg, Regensburg (Germany); Schreyer, A.G.; Stroszczynski, C.; Fellner, C.; Wiggermann, P. [Department of Radiology, University Hospital Regensburg, Regensburg (Germany)

    2013-10-01

    Purpose: The purpose of this study was to assess differences in enhancement effects of liver parenchyma between normal and cirrhotic livers on dynamic, Gd-EOB-DTPA enhanced MRI at 3 T. Materials and methods: 93 patients with normal (n = 54) and cirrhotic liver (n = 39; Child–Pugh class A, n = 18; B, n = 16; C, n = 5) underwent contrast-enhanced MRI with liver specific contrast media at 3 T. T1-weighted volume interpolated breath hold examination (VIBE) sequences with fat suppression were acquired before contrast injection, in the arterial phase (AP), in the late arterial phase (LAP), in the portal venous phase (PVP), and in the hepatobiliary phase (HBP) after 20 min. The relative enhancement (RE) of the signal intensity of the liver parenchyma was calculated for all phases. Results: Mean RE was significantly different among all evaluated groups in the hepatobiliary phase and with increasing severity of liver cirrhosis, a decreasing, but still significant reduction of RE could be shown. Phase depending changes of RE for each group were observed. In case of non-cirrhotic liver or Child–Pugh Score A cirrhosis mean RE showed a significant increase between AP, LAP, PVP and HBP. For Child–Pugh B + C cirrhosis RE increased until PVP, however, there was no change in case of B cirrhosis (p = 0.501) and significantly reduced in case of C cirrhosis (p = 0.043) during HBP. Conclusion: RE of liver parenchyma is negatively affected by increased severity of liver cirrhosis, therefore diagnostic value of HBP could be limited in case of Child Pugh B + C cirrhosis.

  18. Evaluation of dynamic contrast-enhanced T1-weighted perfusion MRI in the differentiation of tumor recurrence from radiation necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Vibeke A. [Glostrup University Hospital, Department of Radiology, Glostrup (Denmark); Glostrup University Hospital, Department of Radiology, Copenhagen Oe (Denmark); Simonsen, Helle J.; Larsson, Henrik B.W. [Glostrup University Hospital, Functional Imaging Unit, Glostrup (Denmark); Glostrup University Hospital, Department of Clinical Physiology, Glostrup (Denmark); Law, Ian [Nuclear Medicine and PET, Department of Clinical Physiology, Copenhagen Oe (Denmark); Hansen, Adam E. [Glostrup University Hospital, Department of Radiology, Glostrup (Denmark); Glostrup University Hospital, Functional Imaging Unit, Glostrup (Denmark)

    2013-03-15

    To investigate if perfusion measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can be used to differentiate radiation necrosis from tumor recurrence in patients with high-grade glioma. The study was approved by the institutional review board and informed consent was obtained from all subjects. 19 patients were recruited following surgery and radiation therapy for glioma. Patients had contrast enhancing lesions, which during the standard MRI examination could not be exclusively determined as recurrence or radiation necrosis. DCE-MRI was used to measure cerebral blood volume (CBV), blood-brain barrier (BBB) permeability and cerebral blood flow (CBF). Subjects also underwent FDG-PET and lesions were classified as either metabolically active or inactive. Follow-up clinical MRI and lesion histology in case of additional tissue resection was used to determine whether lesions were regressing or progressing. Fourteen enhancing lesions could be classified as progressing (11) or regressing (three). An empirical threshold of 2.0 ml/100 g for CBV allowed detection of regressing lesions with a sensitivity of 100 % and specificity of 100 %. FDG-PET and DCE-MRI agreed in classification of tumor status in 13 out of the 16 cases where an FDG-PET classification was obtained. In two of the remaining three patients, MRI follow-up and histology was available and both indicated that the DCE-MRI answer was correct. CBV measurements using DCE-MRI may predict the status of contrast enhancing lesions and give results very similar to FDG-PET with regards to differentiation between tumor recurrence and radiation necrosis. (orig.)

  19. Enhancing endogenous stem cells in the newbornvia delayed umbilical cord clamping

    Institute of Scientific and Technical Information of China (English)

    Christopher Lawton; Sandra Acosta; Nate Watson; Chiara Gonzales-Portillo; hTeo Diamandis; Naoki Tajiri; Yuji Kaneko; Paul R. Sanberg; Cesar V. Borlongan

    2015-01-01

    There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal beneifts including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deifciency anemia in term infants. Human umbilical cord blood con-tains signiifcant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it en-hances blood lfow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant’s susceptibility to both neonatal and age-related diseases.

  20. Enhancing endogenous stem cells in the newborn via delayed umbilical cord clamping

    Directory of Open Access Journals (Sweden)

    Christopher Lawton

    2015-01-01

    Full Text Available There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal benefits including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deficiency anemia in term infants. Human umbilical cord blood contains significant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it enhances blood flow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant′s susceptibility to both neonatal and age-related diseases.

  1. Enhancing endogenous stem cells in the newborn via delayed umbilical cord clamping.

    Science.gov (United States)

    Lawton, Christopher; Acosta, Sandra; Watson, Nate; Gonzales-Portillo, Chiara; Diamandis, Theo; Tajiri, Naoki; Kaneko, Yuji; Sanberg, Paul R; Borlongan, Cesar V

    2015-09-01

    There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal benefits including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deficiency anemia in term infants. Human umbilical cord blood contains significant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it enhances blood flow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant's susceptibility to both neonatal and age-related diseases.

  2. Functional localization of epileptic foci in cats using manganese-enhanced MRI

    Institute of Scientific and Technical Information of China (English)

    Qingxia Kong; Shenggang Sun; Changqin Liu; Jinbai Huang; Haibo Xu

    2006-01-01

    Objective: To determine the encephalic region correlated with epilepsy by manganese-enhanced MRI (MEMRI) and determine the correlation of epilepsy with calcium overloading. Methods: The cats were divided into two groups.The first group underwent EEG examination and ethological observation. The second group underwent MEMRI measurement. Signal enhanced encephalic regions were sectioned. Results: The achievement ratio of convulsive cats intramusclelarly injected with PTZ was 80%. MEMRI showed diffuse signal enhancement in the cerebral cortex of the cats with generalized tonic-clonic convulsive seizures compared with control animals. The enhancement rate of frontal-parietal-occipital lobe was 34.6% and 22.9% in temporal lobe compared with the control groups. Signal enhancement on frontal-parietal lobe persisted for 24 h after epileptic seizures were induced. The neurons of enhanced encephalic regions showed obvious degeneration and necrosis. Conclusion: Seizures can be induced in cats by intramuscular injection of PTZ (55 mg/kg). Frontal-parietal lobe is the correlated encephalic regions of epilepsy. MEMRI plays an important role in localizing and revealing pathogenesis of epileptic seizures.

  3. An evaluation of ischemic stroke using dynamic contrast enhanced perfusion MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Hiroshi; Igarashi, Hironaka; Katayama, Yasuo; Terashi, Akiro [Nippon Medical School, Tokyo (Japan)

    1998-04-01

    To assess the feasibility of dynamic contrast enhanced perfusion MRI, echo planar imaging was performed in 10 patients with ischemic stroke. The relative cerebral blood volume (rCBV), mean transit time (MTT), and relative cerebral blood flow (rCBF) were measured based on moment analysis and the gamma variate method. These measurements, however, are not suitable for the detection of cerebral ischemia during the hyperacute stage. Therefore, we additionally studied the changes in a concentration curve (time-{Delta}R{sup *} curve) of Gd-DTPA, injected into the median vein of the forearm. From the curve the SUM ({Delta}R{sup *}) time to peak and the {Delta}R{sup *} peak, which may be calculated quickly, were determined and were compared to rCBV, MTT, and rCBF, respectively. The rCBV and the rCBF in the ischemic regions were less than those in the contralateral healthy regions, and the MTT in the ischemic regions was longer than that in the contralateral healthy regions. Additionally, SUM ({Delta}R{sup *}) and the {Delta}R{sup *} peak in the ischemic regions were less, and the time to peak in the ischemic regions was longer than the value in the contralateral healthy regions, correlating well to the rCBV, rCBF, and MTT measurements. Also, images of these parameters, depicting the ischemic lesion earlier than conventional T2 weighted images, can be easily made by using an MRI console. These results suggest that the SUM ({Delta}R{sup *}), time to peak and the {Delta}R{sup *} peak images calculated with dynamic contrast enhanced perfusion MRI may be one of the best techniques for the detection of cerebral ischemic lesions during the hyperacute stage. (K.H.)

  4. Dynamic contrast enhanced MRI-derived parameters are potential biomarkers of therapeutic response in bladder carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chakiba, Camille [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Cornelis, François [Department of Radiology, Pellegrin Hospital, Bordeaux (France); Descat, Edouard [Department of Radiology, Saint-Augustin Clinic, Bordeaux (France); Gross-Goupil, Marine [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Sargos, Paul [Department of Radiotherapy, Bergonié Cancer Institute, Bordeaux (France); Roubaud, Guilhem [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Houédé, Nadine, E-mail: nadine.houede@chu-nimes.fr [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Department of Medical Oncology, Nimes University Hosptital, Nîmes (France)

    2015-06-15

    Highlights: • DCE-MRI parameters could be useful biomarker for patients with localized bladder carcinoma. • Rate of relapse is lower for good responders assessed by DCE-MRI. • The use of DCE-MRI parameters may improve the standardization of patients’ selection before surgery. - Abstract: Objectives: To evaluate the performance of dynamic contrast enhanced (DCE) magnetic resonance (MR) imaging to assess the histological response after chemotherapy on bladder carcinoma. Methods: From 2008 to 2010, 12 patients presenting localized urothelial carcinoma of the bladder were prospectively evaluated by DCE-MR imaging before and after two courses of cisplatin-based neoadjuvant chemotherapy. Size and thickness of tumours were measured. Relative enhancement at the arterial (rSI{sub 35s}) and venous phases (rSI{sub 80s}) of each tumour was obtained. Histological response was assessed and outcomes were recorded. Results: Histological examination after neoadjuvant chemotherapy concluded as pathological complete response (pCR) for 6 out of 12 patients. Five patients developed recurrences (4/6 no pCR and 1/6 pCR). Significant differences, between before and after treatment, were found for patients with complete pathological response after chemotherapy for all MR quantitative values. Tumours decreased in size and thickness (both P = 0.03). After treatment, rSI{sub 80s} was significantly different between pCR and non-pCR patients (P = 0.04) with a cut-off value of 40%. For this cut-off, sensitivity, specificity and accuracy were 83.33%. Similar recurrence free survivals were obtained if applying the MR cut-off value or the histopathological findings. Conclusion: Our results suggest that DCE-MR imaging may be a useful biomarker for patients with localized bladder carcinoma, improving selection before surgery.

  5. Targeted Multifunctional Nanoparticles cure and image Brain Tumors: Selective MRI Contrast Enhancement and Photodynamic Therapy

    Science.gov (United States)

    Kopelman, Raoul

    2008-03-01

    Aimed at targeted therapy and imaging of brain tumors, our approach uses targeted, multi-functional nano-particles (NP). A typical nano-particle contains a biologically inert, non-toxic matrix, biodegradable and bio-eliminable over a long time period. It also contains active components, such as fluorescent chemical indicators, photo-sensitizers, MRI contrast enhancement agents and optical imaging dyes. In addition, its surface contains molecular targeting units, e.g. peptides or antibodies, as well as a cloaking agent, to prevent uptake by the immune system, i.e. enabling control of the plasma residence time. These dynamic nano-platforms (DNP) contain contrast enhancement agents for the imaging (MRI, optical, photo-acoustic) of targeted locations, i.e. tumors. Added to this are targeted therapy agents, such as photosensitizers for photodynamic therapy (PDT). A simple protocol, for rats implanted with human brain cancer, consists of tail injection with DNPs, followed by 5 min red light illumination of the tumor region. It resulted in excellent cure statistics for 9L glioblastoma.

  6. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study

    Directory of Open Access Journals (Sweden)

    Alejandra eRosales-Lagarde

    2012-06-01

    Full Text Available Converging evidence from animal and human studies suggest that REM sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI. Twenty healthy subjects were randomly assigned to two groups: selective REM sleep deprivation (REM-D, by awakening them at each REM sleep onset, or NREM sleep interruptions (NREM-I as control for potential non-specific effects of awakenings and lack of sleep. In a within-subject design, a visual emotional-reactivity task was performed in the scanner before and 24 hours after sleep manipulation. Behaviorally, emotional reactivity was enhanced relative to baseline in the REM deprived group only. In terms of fMRI signal, there was an overall decrease in activity in the NREM-I group the second time subjects performed the task, particularly in regions involved in emotional processing, such as occipital and temporal areas, as well as in the ventrolateral prefrontal cortex, involved in top-down emotion regulation. In contrast, activity in these areas remained the same level or even increased in the REM-D group, compared to their baseline level.Taken together, these results suggest that lack of REM sleep in humans is associated with enhanced emotional reactivity, both at behavioral and neural levels, and thus highlight the specific role of REM sleep in regulating the neural substrates for emotional responsiveness.

  7. Hemophilic arthropathy of the knee joint: static and dynamic Gd-DTPA - enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Naegele, M. [Dept. of Radiology, Univ. Bonn (Germany); Bruening, R. [Dept. of Radiology, Univ. Muenchen (Germany); Kunze, V. [Dept. of Radiology, Univ. Bonn (Germany); Eickhoff, H. [Dept. of Orthopedic Surgery, Troisdorf (Germany); Koch, W. [Dept. of Orthopedic Surgery, Troisdorf (Germany); Reiser, M. [Dept. of Radiology, Univ. Muenchen (Germany)

    1995-12-31

    A total of 17 patients with hemophilic arthropathy of the knee joint were studied with static and dynamic MRI before and after an IV bolus injection of Gadolinium-DTPA (Gd-DTPA; 0.1 mmol/kg body weight). The T1-weighted spin-echo (SE) and gradient-echo (fast-field echo [FFE]) sequences were applied. The FFE sequences of eight consecutive scans carried out over a time interval of 160 s were used in order to determine the time to signal intensity (SI) curves of the synovial proliferations surrounding soft tissue, bone marrow, and joint effusion. After the administration of a contrast agent, synovial proliferations exhibited an increase on FFE and SE images of 47.7% (SD {+-} 14.3%) and 37.4% (SD {+-} 11.2%), respectively, whereas muscle and fatty tissue, tendons, bone marrow, and joint effusion revealed only a minor increase in SI. The gradient of SI (ratio SI/time) of pannus was 39.6%/min (SD {+-} 7.7%/min) and differed significantly (P < 0.001) from that of bone marrow, fatty tissue, muscle tissue, tendons, and joint effusion (P < 0.05). In contrast to synovial proliferations in rheumatoid arthritis, no differentiation between various pannus vascularities based on the degree of enhancement was possible. The Gd-DTPA-enhanced MRI studies delineate and quantify the synovial proliferations in hemophilic arthropathy. Dynamic studies in hemophilic arthropathy do not provide qualitative assessment of the inflammatory process. (orig.)

  8. Relationship between diffusion parameters derived from intravoxel incoherent motion MRI and perfusion measured by dynamic contrast-enhanced MRI of soft tissue tumors.

    Science.gov (United States)

    Marzi, Simona; Stefanetti, Linda; Sperati, Francesca; Anelli, Vincenzo

    2016-01-01

    Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast-enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty-eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion-related diffusion coefficient D* were estimated using a bi-exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3-5 s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann-Whitney test was used to evaluate the differences between all variables in patients with non-myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non-myxoid tumors compared with myxoid tumors (p = 0.004 and p = 0.003, respectively). MSI was significantly higher in non-myxoid tumors than in myxoid tumors (p = 0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion-related IVIM parameters and perfusion measured by DCE MRI.

  9. Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI - a comparison with contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Eshed, Iris [The Sheba Medical Center, Department of Diagnostic Imaging, Tel Hashomer (Israel); Tel Aviv University, Sackler School of Medicine, Tel Aviv (Israel); Krabbe, Simon; Axelsen, Mette; Pedersen, Susanne Juhl [Copenhagen University Hospital Glostrup, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen (Denmark); Oestergaard, Mikkel [Copenhagen University Hospital Glostrup, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen (Denmark); Copenhagen University Hospital Gentofte, Department of Rheumatology/C, Copenhagen (Denmark); Boeyesen, Pernille [Diakonhjemmet Hospital, Department of Rheumatology, Oslo (Norway); Moeller, Jakob M. [Copenhagen University Hospital at Herlev, Department of Radiology, Copenhagen (Denmark); Therkildsen, Flemming [Metropolitan University College, Copenhagen (Denmark); Madsen, Ole Rintek [Copenhagen University Hospital Gentofte, Department of Rheumatology/C, Copenhagen (Denmark)

    2015-04-01

    To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2{sup nd}-5{sup th} metacarpophalangeal joints) at 4 different field-strengths (0.23 T/0.6 T/1.5 T/3.0 T) on the same day. Seven protocols using a STIR sequence with different field-strengths, coils (flex coils/dedicated phased-array extremity coils) and resolution were applied and scored blindly for synovitis (OMERACT-RAMRIS method). A 1.5 T post-contrast T1-weighted sequence was used as gold standard reference. Fair-good agreement (ICC=0.38-0.72) between the standard reference and the different STIR protocols (best agreement with extremity coil and small voxel size at 1.5 T). The accuracy for presence/absence of synovitis was very high per person (0.80-1.0), and moderate-high per joint (0.63-0.85), whereas exact agreements on scores were moderate (0.50-0.66). The intrareader agreement (15 patients and 3 controls) on presence/absence of synovitis was very high (0.87-1.0). Unenhanced MRI using STIR sequence is only moderately reliable for assessing hand synovitis in RA, when contrast-enhanced MRI is considered the gold standard reference. Contrast injection, field strength and coil type influence synovitis assessment, and should be considered before performing MRI in clinical trials and practice. (orig.)

  10. Enhancement and suppression in a lexical interference fMRI-paradigm.

    Science.gov (United States)

    Abel, Stefanie; Dressel, Katharina; Weiller, Cornelius; Huber, Walter

    2012-03-01

    Previous picture-word interference (PWI) fMRI-paradigms revealed ambiguous mechanisms underlying facilitation and inhibition in healthy subjects. Lexical distractors revealed increased (enhancement) or decreased (suppression) activation in language and monitoring/control areas. Performing a secondary examination and data analysis, we aimed to illuminate the relation between behavioral and neural interference effects comparing target-related distractors (REL) with unrelated distractors (UNREL). We hypothesized that interference involves both (A) suppression due to priming and (B) enhancement due to simultaneous distractor and target processing. Comparisons to UNREL should remain distractor unspecific even at a low threshold. (C) Distractor types with common characteristics should reveal overlapping brain areas. In a 3T MRI scanner, participants were asked to name pictures while auditory words were presented (stimulus onset asynchrony [SOA] = -200 msec). Associatively and phonologically related distractors speeded responses (facilitation), while categorically related distractors slowed them down (inhibition) compared to UNREL. As a result, (A) reduced brain activations indeed resembled previously reported patterns of neural priming. Each target-related distractor yielded suppressions at least in areas associated with vision and conflict/competition monitoring (anterior cingulate cortex [ACC]), revealing least priming for inhibitors. (B) Enhancements concerned language-related but distractor-unspecific regions. (C) Some wider brain regions were commonly suppressed for combinations of distractor types. Overlapping areas associated with conceptual priming were found for facilitatory distractors (inferior frontal gyri), and areas related to phonetic/articulatory processing (precentral gyri and left parietal operculum/insula) for distractors sharing feature overlap. Each distractor with semantic relatedness revealed nonoverlapping suppressions in lexical

  11. Simultaneous Acquisition of Multi-nuclei Enhanced NMR/MRI by Solution State Dynamic Nuclear Polarization

    CERN Document Server

    He, Yugui; Feng, Jiwen; Huang, Chongyang; Chen, Fang; Liu, Maili; Liu, Chaoyang

    2015-01-01

    Dynamic nuclear polarization (DNP) has become a very important hyperpolarization method because it can dramatically increase the sensitivity of nuclear magnetic resonance (NMR) of various molecules. Liquid-state DNP based on Overhauser effect is capable of directly enhancing polarizations of all kinds of nuclei in the system. The combination of simultaneous Overhauser multi-nuclei enhancements with the multi-nuclei parallel acquisitions provides a variety of important applications in both MR spectroscopy (MRS) and image (MRI). Here we present two simple illustrative examples for simultaneously enhanced multi-nuclear spectra and images to demonstrate the principle and superiority. We have observed very large simultaneous DNP enhancements for different nuclei, such as 1H and 23Na, 1H and 31P, 19F and 31P, especially for the first time to report sodium ion enhancement in liquid. We have also obtained the simultaneous imaging of 19H and 31P at low field by solution-state DNP for the first time. This method can ob...

  12. Diagnosis of hepatocellular carcinoma with gadoxetic acid-enhanced MRI: 2016 Consensus Recommendations of the Korean Society of Abdominal Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Mi-Suk [Yonsei University College of Medicine, Severance Hospital, Seoul (Korea, Republic of)

    2017-06-15

    Diagnosis of hepatocellular carcinoma (HCC) with gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) poses certain unique challenges beyond the scope of current guidelines. The regional heterogeneity of HCC in demographic characteristics, prevalence, surveillance, and socioeconomic status necessitates different treatment approaches, leading to variations in survival outcomes. Considering the medical practices in Korea, the Korean Society of Abdominal Radiology (KSAR) study group for liver diseases has developed expert consensus recommendations for diagnosis of HCC by gadoxetic acid-enhanced MRI with updated perspectives, using a modified Delphi method. During the 39th Scientific Assembly and Annual Meeting of KSAR (2016), consensus was reached on 12 of 16 statements. These recommendations might serve to ensure a more standardized diagnosis of HCC by gadoxetic acid-enhanced MRI.

  13. Multi-delay arterial spin labeling perfusion MRI in moyamoya disease-comparison with CT perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); University of Chinese Academy of Sciences, Graduate School, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States); Yu, Songlin [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); University of California Los Angeles, Department of Neurology, Los Angeles (United States); Alger, Jeffry R.; Wang, Danny J.J. [University of California Los Angeles, Department of Neurology, Los Angeles (United States); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States); Zuo, Zhentao; Wang, Bo [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); Chen, Juan [Beijing Hospital, Department of Radiology, Beijing (China); Wang, Rong; Zhao, Jizong [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); An, Jing [Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen (China); Xue, Rong [Chinese Academy of Sciences, State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Beijing (China); UCLA-Beijing Joint Center for Advanced Brain Imaging, Los Angeles, CA (United States)

    2014-05-15

    To present a multi-delay pseudo-continuous ASL (pCASL) protocol that offers simultaneous measurements of cerebral blood flow (CBF) and arterial transit time (ATT), and to study correlations between multi-delay pCASL and CT perfusion in moyamoya disease. A 4 post-labeling delay (PLD) pCASL protocol was applied on 17 patients with moyamoya disease who also underwent CT perfusion imaging. ATT was estimated using the multi-delay protocol and included in the calculation of CBF. ASL and CT perfusion images were rated for lesion severity/conspicuity. Pearson correlation coefficients were calculated across voxels between the two modalities in grey and white matter of each subject respectively and between normalized mean values of ASL and CT perfusion measures in major vascular territories. Significant associations between ASL and CT perfusion were detected using subjective ratings, voxel-wise analysis in grey and white matter and region of interest (ROI)-based analysis of normalized mean perfusion. The correlation between ASL CBF and CT perfusion was improved using the multi-delay pCASL protocol compared to CBF acquired at a single PLD of 2 s (P < 0.05). There is a correlation between perfusion data from ASL and CT perfusion imaging in patients with moyamoya disease. Multi-delay ASL can improve CBF quantification, which could be a prognostic imaging biomarker in patients with moyamoya disease. (orig.)

  14. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    Energy Technology Data Exchange (ETDEWEB)

    Fallenberg, E.M.; Renz, D.M. [Charite - Universitaetsmedizin Berlin, Clinic of Radiology, Berlin (Germany); Dromain, C. [Institut Gustave Roussy, Department of Radiology, Villejuif cedex (France); Diekmann, F. [St. Joseph-Stift Bremen, Department of Medical Imaging, Bremen (Germany); Engelken, F.; Krohn, M.; Singh, J.M.; Bick, U. [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Ingold-Heppner, B. [Charite - Universitaetsmedizin Berlin, Institute of Pathology, Berlin (Germany); Winzer, K.J. [Charite - Universitaetsmedizin Berlin, Breast Center, Department of Gynecology, Berlin (Germany)

    2014-01-15

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  15. Femoral head vascularisation in Legg-Calve-Perthes disease: comparison of dynamic gadolinium-enhanced subtraction MRI with bone scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Lamer, Sylvie; Dorgeret, Sophie; Brillet, Pierre-Yves; Hassan, Max; Sebag, Guy H. [Department of Paediatric Radiology, Hopital Robert Debre, 48 boulevard Serurier, 75935 Paris Cedex (France); Lariboisiere-Saint-Louis University, Paris (France); Khairouni, Abdeslam; Mazda, Keyvan; Bacheville, Eric; Pennecot, Georges F. [Department of Paediatric Orthopaedics, Hopital Robert Debre, Paris (France); Bloch, Juliette [Department of Biostatistics, Hopital Robert Debre, Paris (France)

    2002-08-01

    Heading AbstractBackground. It has been reported that MRI using a dynamic gadolinium-enhanced subtraction technique can allow the early identification of ischaemia and the pattern of revascularisation in Legg-Calve-Perthes (LCP) disease with increased spatial and contrast resolution. Therefore, dynamic gadolinium-enhanced subtraction (DGS) MRI may be a possible non-ionising substitute for bone scintigraphy.Objective. The purpose of this prospective study was to compare DGS MRI and bone scintigraphy in the assessment of femoral head perfusion in LCP disease.Materials and methods. Twenty-six DGS MR images and bone scintigraphies of 25 hips in 23 children were obtained at different stages of LCP disease; three stage I, 12 stage II, six stage III and five stage IV (Waldenstroem classification). The extent of necrosis, epiphyseal revascularisation pathways (lateral pillar, medial pillar, and/or transphyseal perfusion) and metaphyseal changes were analysed.Results. Total agreement between both techniques was noted in the depiction of epiphyseal necrosis (kappa=1), and metaphyseal abnormalities (kappa=0.9). DGS MRI demonstrated better revascularisation in the lateral (kappa=0.62) and medial pillars (kappa=0.52). The presence of basal transphyseal reperfusion was more conspicuous with MRI.Conclusions. DGS MRI allows early detection of epiphyseal ischaemia and accurate analysis of the different revascularisation patterns. These changes are directly related to the prognosis of LCP disease and can aid therapeutic decision making. (orig.)

  16. Assessment of vessel permeability by combining dynamic contrast-enhanced and arterial spin labeling MRI.

    Science.gov (United States)

    Liu, Ho-Ling; Chang, Ting-Ting; Yan, Feng-Xian; Li, Cheng-He; Lin, Yu-Shi; Wong, Alex M

    2015-06-01

    The forward volumetric transfer constant (K(trans)), a physiological parameter extracted from dynamic contrast-enhanced (DCE) MRI, is weighted by vessel permeability and tissue blood flow. The permeability × surface area product per unit mass of tissue (PS) in brain tumors was estimated in this study by combining the blood flow obtained through pseudo-continuous arterial spin labeling (PCASL) and K(trans) obtained through DCE MRI. An analytical analysis and a numerical simulation were conducted to understand how errors in the flow and K(trans) estimates would propagate to the resulting PS. Fourteen pediatric patients with brain tumors were scanned on a clinical 3-T MRI scanner. PCASL perfusion imaging was performed using a three-dimensional (3D) fast-spin-echo readout module to determine blood flow. DCE imaging was performed using a 3D spoiled gradient-echo sequence, and the K(trans) map was obtained with the extended Tofts model. The numerical analysis demonstrated that the uncertainty of PS was predominantly dependent on that of K(trans) and was relatively insensitive to the flow. The average PS values of the whole tumors ranged from 0.006 to 0.217 min(-1), with a mean of 0.050 min(-1) among the patients. The mean K(trans) value was 18% lower than the PS value, with a maximum discrepancy of 25%. When the parametric maps were compared on a voxel-by-voxel basis, the discrepancies between PS and K(trans) appeared to be heterogeneous within the tumors. The PS values could be more than two-fold higher than the K(trans) values for voxels with high K(trans) levels. This study proposes a method that is easy to implement in clinical practice and has the potential to improve the quantification of the microvascular properties of brain tumors.

  17. Detection of hepatocellular carcinoma in gadoxetic acid-enhanced MRI and diffusion-weighted MRI with respect to the severity of liver cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ah Yeong; Kim, Young Kon; Lee, Min Woo; Park, Min Jung; Hwang, Jiyoung; Lee, Mi Hee; Lee, Jae Won [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)], e-mail: jmyr@dreamwiz.com

    2012-10-15

    Background As gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) have been widely used for the evaluation of hepatocellular carcinoma (HCC), it is clinically relevant to determine the diagnostic efficacy of gadoxetic acid-enhanced MRI and DWI for detection of HCCs with respect to the severity of liver cirrhosis. Purpose To compare the diagnostic accuracy and sensitivity of gadoxetic acid-enhanced MRI and DWI for detection of HCCs with respect to the severity of liver cirrhosis. Material and Methods A total of 189 patients with 240 HCCs ({<=}3.0 cm) (Child-Pugh A, 81 patients with 90 HCCs; Child-Pugh B, 65 patients with 85 HCCs; Child-Pugh C, 43 patients with 65 HCCs) underwent DWI and gadoxetic acid-enhanced MRI at 3.0 T. A gadoxetic acid set (dynamic and hepatobiliary phase plus T2-weighted image) and DWI set (DWI plus unenhanced MRIs) for each Child-Pugh class were analyzed independently by two observers for detecting HCCs using receiver-operating characteristic analysis. The diagnostic accuracy and sensitivity were calculated. Results There was a trend toward decreased diagnostic accuracy for gadoxetic acid and DWI set with respect to the severity of cirrhosis (Child-Pugh A [mean 0.974, 0.961], B [mean 0.904, 0.863], C [mean 0.779, 0.760]). For both observers, the sensitivities of both image sets were highest in Child-Pugh class A (mean 95.6%, 93.9%), followed by class B (mean 83.0%, 77.1%), and class C (mean 60.6%, 60.0%) (P < 0.05). Conclusion In HCC detection, the diagnostic accuracy and sensitivity for gadoxetic acid-enhanced MRI and DWI were highest in Child-Pugh class A, followed by Child-Pugh class B, and Child-Pugh class C, indicating a tendency toward decreased diagnostic capability with the severity of cirrhosis.

  18. Nanodiamond-Manganese dual mode MRI contrast agents for enhanced liver tumor detection.

    Science.gov (United States)

    Hou, Weixin; Toh, Tan Boon; Abdullah, Lissa Nurrul; Yvonne, Tay Wei Zheng; Lee, Kuan J; Guenther, Ilonka; Chow, Edward Kai-Hua

    2017-04-01

    Contrast agent-enhanced magnetic resonance (MR) imaging is critical for the diagnosis and monitoring of a number of diseases, including cancer. Certain clinical applications, including the detection of liver tumors, rely on both T1 and T2-weighted images even though contrast agent-enhanced MR imaging is not always reliable. Thus, there is a need for improved dual mode contrast agents with enhanced sensitivity. We report the development of a nanodiamond-manganese dual mode contrast agent that enhanced both T1 and T2-weighted MR imaging. Conjugation of manganese to nanodiamonds resulted in improved longitudinal and transverse relaxivity efficacy over unmodified MnCl2 as well as clinical contrast agents. Following intravenous administration, nanodiamond-manganese complexes outperformed current clinical contrast agents in an orthotopic liver cancer mouse model while also reducing blood serum concentration of toxic free Mn(2+) ions. Thus, nanodiamond-manganese complexes may serve as more effective dual mode MRI contrast agent, particularly in cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Evaluating automated dynamic contrast enhanced wrist 3 T MRI in healthy volunteers: One-year longitudinal observational study

    Energy Technology Data Exchange (ETDEWEB)

    Rastogi, Anshul, E-mail: anshul.rastogi@bartshealth.nhs.uk [Kennedy Institute of Rheumatology, Imperial College London (United Kingdom); Kubassova, Olga, E-mail: olga@imageanalysis.org.uk [Image Analysis, Leeds (United Kingdom); Krasnosselskaia, Lada V., E-mail: solaguz@yahoo.com [Imaging Sciences Department, Imperial College London (United Kingdom); Lim, Adrian K.P., E-mail: a.lim@imperial.ac.uk [Department of Radiology, Imperial College Healthcare NHS Trust, London (United Kingdom); Satchithananda, Keshthra, E-mail: keshthra.satchithananda@imperial.nhs.uk [Department of Radiology, Imperial College Healthcare NHS Trust, London (United Kingdom); Boesen, Mikael, E-mail: mikael.boesen@gmail.com [Department of Radiology and the Parker Institute, Frederiksberg and Bispebjerg Hospitals (Denmark); Binks, Michael, E-mail: michael.h.binks@gsk.com [GlaxoSmithKline, Stevenage, SG1 2NY (United Kingdom); Hajnal, Joseph V., E-mail: jo.hajnal@kcl.ac.uk [Imaging Sciences Department, Imperial College London (United Kingdom); Taylor, Peter C., E-mail: peter.taylor@kennedy.ox.ac.uk [Kennedy Institute of Rheumatology, Imperial College London (United Kingdom)

    2013-08-15

    Rational and Objective: Dynamic contrast enhanced (DCE)-MRI has great potential to provide quantitative measure of inflammatory activity in rheumatoid arthritis. There is no current benchmark to establish the stability of signal in the joints of healthy subjects when imaged with DCE-MRI longitudinally, which is crucial so as to differentiate changes induced by treatment from the inherent variability of perfusion measures. The objective of this study was to test a pixel-by-pixel parametric map based approach for analysis of DCE-MRI (Dynamika) and to investigate the variability in signal characteristics over time in healthy controls using longitudinally acquired images. Materials and Methods: 10 healthy volunteers enrolled, dominant wrists were imaged with contrast enhanced 3T MRI at baseline, week 12, 24 and 52 and scored with RAMRIS, DCE-MRI was analysed using a novel quantification parametric map based approach. Radiographs were obtained at baseline and week 52 and scored using modified Sharp van der Heidje method. RAMRIS scores and dynamic MRI measures were correlated. Results: No erosions were seen on radiographs, whereas MRI showed erosion-like changes, low grade bone marrow oedema and low-moderate synovial enhancement. The DCE-MRI parameters were stable (baseline scores, variability) (mean ± st.dev); in whole wrist analysis, ME{sub mean} (1.3 ± 0.07, −0.08 ± 0.1 at week 24) and IRE{sub mean} (0.008 ± 0.004, −0.002 ± 0.005 at week 12 and 24). In the rough wrist ROI, ME{sub mean} (1.2 ± 0.07, 0.04 ± 0.02 at week 52) and IRE{sub mean} (0.001 ± 0.0008, 0.0006 ± 0.0009 at week 52) and precise wrist ROI, ME{sub mean} (1.2 ± 0.09, 0.04 ± 0.04 at week 52) and IRE{sub mean} (0.001 ± 0.0008, 0.0008 ± 0.001 at week 24 and 52). The Dynamic parameters obtained using fully automated analysis demonstrated strong, statistically significant correlations with RAMRIS synovitis scores. Conclusion: The study demonstrated that contrast enhancement does occur in

  20. Evaluation of the diagnostic efficacy of SPIO enhanced MRI in patients with focal hepatic lesions. Comparison with CECT and CTAP

    Energy Technology Data Exchange (ETDEWEB)

    Kasugai, Hisashi; Katayama, Nobuhito; Sakai, Shigeru; Yamakawa, Tatsuo [Teikyo Univ., Kawasaki, Kanagawa (Japan). Mizonokuchi Hospital

    2002-11-01

    The aim of this study was to compare the diagnostic efficacy of superparamagnetic iron oxide (SPIO)-enhanced MRI for the detection and diagnostic accuracy of focal liver lesions with helical contrast enhanced CT (CECT) and CT during arterial portography (CTAP). Thirty-nine patients (25 men and 14 women, mean age 63.5 years) were examined by SPIO-MRI and triple-phase CECT. Eleven of them were also examined by CTAP. There were a total of 96 confirmed focal hepatic lesions, 61 metastatic cancers in 18 patients and 35 hepatocellular carcinomas (HCCs) in 21 patients. Final diagnosis was established by operation in 25 cases, by biopsy in 7 cases, and by progression of disease on follow-up examination in the other 7 cases. The sensitivity of SPIO-MRI for HCC detection was almost equal to CECT, but that of SPIO-MRI for metastatic cancer detection, especially cancers smaller than 1 cm in size, was significantly superior to CECT. The sensitivity of SPIO-MRI for both HCC and metastatic cancer detection was almost equal to that of CTAP, but the specificity of SPIO-MRI for detection of both lesions was significantly superior to that of CTAP because CTAP produced a higher incidence of false-positive findings. In conclusion, SPIO-MRI could take the place of CTAP as a non-invasive excellent modality to determine the distribution of hepatic lesions preoperatively. SPIO-MRI could also be a useful modality to follow liver metastasis postoperatively in patients with advanced digestive cancers. (author)

  1. Can cerebrovascular reactivity be assessed by dynamic susceptibility contrast-enhanced MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Berthezene, Y.; Meyer, R.; Froment, J.C. [Department of Radiology, Creatis UMR CNRS 5515, Neurological Hospital, Lyon (France); Nighoghossian, N.; Trouillas, P. [Neurology, Cerebrovascular Disease and Ataxia Research Center, Neurological Hospital, Lyon (France); Damien, J.; Cinotti, L. [Department of Nuclear Medicine, Neurological Hospital, Lyon (France); Adeleine, P. [Medical Informatics Laboratory, UFR Alexis Carrel, Lyon (France)

    1998-01-01

    s The acetazolamide (ACZ) test is performed to evaluate the decrease in cerebral perfusion pressure (CPP) by investigation of vasomotor reactivity (VMR). Our aim was to study cerebral blood flow and blood volume changes induced by the ACZ test in healthy control subjects using dynamic susceptibility contrast-enhanced gradient-echo MRI (DSC-MRI). A FLASH sequence was used to produce susceptibility-weighted images during an intravenous injection of 0.1 mmol/kg gadopentetate dimeglumine (Gd-DTPA). After the first dynamic study, 1 g acetazolamide was given intravenously and 10 min later a second bolus of Gd-DTPA was injected. Using the indicator-dilution theory, relative cerebral blood volume and relative cerebral blood flow were estimated. In healthy subjects the ACZ test induced a significant increase in relative blood volume (from 80.5 {+-} 10.7 to 113.4 {+-} 11.9) and relative blood flow (from 5.73 {+-} 0.96 to 7.5 {+-} 0.97), symmetrically in the cerebral hemispheres. This approach might be promising in the understanding of cerebral haemodynamics in patients with vascular disorders. (orig.) With 1 fig., 3 tabs., 24 refs.

  2. New method for 3D parametric visualization of contrast-enhanced pulmonary perfusion MRI data

    Energy Technology Data Exchange (ETDEWEB)

    Kuder, Tristan A.; Eichinger, Monika; Ley, Sebastian; Puderbach, Michael; Kauczor, Hans-Ulrich [Deutsches Krebsforschungszentrum, Department of Radiology, E010, Heidelberg (Germany); Risse, Frank [Deutsches Krebsforschungszentrum, Department of Medical Physics in Radiology, Heidelberg (Germany); Fink, Christian [Deutsches Krebsforschungszentrum, Department of Radiology, E010, Heidelberg (Germany); Medical Faculty Mannheim - University of Heidelberg, Department of Clinical Radiology, University Hospital Mannheim, Mannheim (Germany)

    2008-02-15

    Three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (3D DCE-MRI) has been proposed for the assessment of regional perfusion. The aim of this work was the implementation of an algorithm for a 3D parametric visualization of lung perfusion using different cutting planes and volume rendering. Our implementation was based on 3D DCE-MRI data of the lungs of five patients and five healthy volunteers. Using the indicator dilution theory, the regional perfusion parameters, tissue blood flow, blood volume and mean transit time were calculated. Due to the required temporal resolution, the volume elements of dynamic MR data sets show a reduced spatial resolution in the z-direction. Therefore, perfusion parameter volumes were interpolated. Linear interpolation and a combination of linear and nearest-neighbor interpolation were evaluated. Additionally, ray tracing was applied for 3D visualization. The linear interpolation algorithm caused interpolation errors at the lung borders. Using the combined interpolation, visualization of perfusion information in arbitrary cutting planes and in 3D using volume rendering was possible. This facilitated the localization of perfusion deficits compared with the coronal orientated source data. The 3D visualization of perfusion parameters using a combined interpolation algorithm is feasible. Further studies are required to evaluate the additional benefit from the 3D visualization. (orig.)

  3. Fluctuations in eGFR in relation to unenhanced and enhanced MRI and CT outpatients

    DEFF Research Database (Denmark)

    Azzouz, Manal; Rømsing, Janne; Thomsen, Henrik S

    2014-01-01

    OBJECTIVE: To study fluctuations in estimated glomerular filtration rate (eGFR) in relation to contrast medium (CM) enhanced magnetic resonance imaging (MRI) and computed tomography (CT) compared to control groups in outpatients. MATERIALS AND METHODS: eGFR was determined right before the imaging...... relevant rise in eGFR after three days in all four groups. The average eGFR variation was 4.8ml/min/1.73m(2). There were large variations in eGFR between the two measurements in 45.8% of the patients as they had a change greater than ±10ml/min/1.73m(2). Only three patients fulfilled the contrast......-induced nephropathy (CIN) requirement when the definition s-creatinine ≥44μmol/l (0.5mg/dl) was used. CONCLUSIONS: eGFR in outpatients undergoing MRI or CT did vary independently of whether the patient received contrast or not. The findings probably reflect the natural variations in s-creatinine levels. This should...

  4. Fluctuations in eGFR in relation to unenhanced and enhanced MRI and CT outpatients

    Energy Technology Data Exchange (ETDEWEB)

    Azzouz, Manal, E-mail: manalazzouz@gmail.com [Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, DK 2730 Herlev (Denmark); Rømsing, Janne [Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø (Denmark); Thomsen, Henrik S. [Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, DK 2730 Herlev (Denmark)

    2014-06-15

    Objective: To study fluctuations in estimated glomerular filtration rate (eGFR) in relation to contrast medium (CM) enhanced magnetic resonance imaging (MRI) and computed tomography (CT) compared to control groups in outpatients. Materials and methods: eGFR was determined right before the imaging procedure and three days later at the department or at the patient's home. The iodine-based and gadolinium-based contrast media were the same as used for all other examinations at the department. Results: A total of 716 patients completed the study. There was a statistically significant, but not clinically relevant rise in eGFR after three days in all four groups. The average eGFR variation was 4.8 ml/min/1.73 m{sup 2}. There were large variations in eGFR between the two measurements in 45.8% of the patients as they had a change greater than ±10 ml/min/1.73 m{sup 2}. Only three patients fulfilled the contrast-induced nephropathy (CIN) requirement when the definition s-creatinine ≥44 μmol/l (0.5 mg/dl) was used. Conclusions: eGFR in outpatients undergoing MRI or CT did vary independently of whether the patient received contrast or not. The findings probably reflect the natural variations in s-creatinine levels. This should be taken into consideration when CIN is studied.

  5. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

    2015-07-15

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  6. Serial MRI study of the enhanced therapeutic effects of liposome-encapsulated citicoline in cerebral ischemia.

    Science.gov (United States)

    Ramos-Cabrer, Pedro; Agulla, Jesús; Argibay, Bárbara; Pérez-Mato, María; Castillo, José

    2011-02-28

    Liposome encapsulation of active principles enhances their bioavailability to the brain. We investigated whether encapsulation of citicoline in liposomes increases its therapeutic effects in ischemia, performing a longitudinal MRI study of lesion volumes and edema in an animal model of stroke. Nineteen rats were submitted to permanent occlusion of the middle cerebral artery and treated with: (1) saline, (2) intraperitoneal citicoline (500mg/kg), (3) intravenous citicoline (48mg/kg), and (4) intravenous liposome-encapsulated citicoline (48mg/kg). Lesion volumes were measured by MRI at days 0, 1, 3 and 7 following surgery. Encapsulation in liposomes increased the therapeutic effects of citicoline, as reflected by a 32% reduction of the infarct sizes at day 7, in contrast with controls where infarct sizes at day 7 increased by 39%, respect to values at day 0. Intravenously injected citicoline reduced infarct sizes by 9% while intraperitoneal citicoline resulted in an increase of infarct sizes by 10%. A slight (not significant) reduction of edema formation was observed for animals treated with citicoline, in all of its delivery forms. Liposome-encapsulated citicoline causes a noticeable reduction in lesion volumes as compared to free citicoline (either i.p. or i.v.) at days 1, 3 and 7 following permanent stroke.

  7. Diagnostic accuracy of segmental enhancement inversion for the diagnosis of renal oncocytoma using biphasic computed tomography (CT) and multiphase contrast-enhanced magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Schieda, Nicola; McInnes, Matthew D.F. [The University of Ottawa, The Ottawa Hospital, Department of Medical Imaging, Ottawa, Ontario (Canada); Al-Subhi, Maali; Flood, Trevor A.; El-Khodary, Mohammed [The University of Ottawa, The Ottawa Hospital, Department of Anatomical Pathology, Ottawa, ON (Canada)

    2014-11-15

    Segmental enhancement inversion (SEI) is a controversial imaging finding reportedly specific for the diagnosis of renal oncocytoma. The purpose of this study was to re-evaluate SEI using biphasic CT and multiphase MRI. With research ethics board approval, a retrospective analysis of patients with resection or biopsy of oncocytoma or chromophobe renal cell carcinoma (Ch-RCC) between 2008-2012 was performed. Twenty-four patients with oncocytoma and 13 patients with Ch-RCC underwent CT, while 13 patients with oncocytoma and 10 patients with Ch-RCC underwent MRI. Two blinded radiologists reviewed the CT and MRI studies independently in separate sessions to assess for SEI. A third radiologist established consensus. Interobserver variability was calculated and diagnostic accuracy was compared using ROC and the Fisher exact test. There was no difference in detection of SEI between oncocytoma and Ch-RCC at CT [both readers (p = 0.65, 0.5) and consensus review (p = 0.29)] or MRI [both readers (p = 0.64, 0.74) and consensus review (p = 0.53)]. The interobserver variability at CT (K = 0.28-0.33) and MRI (K = 0.25-0.44) was fair. The sensitivity and specificity for diagnosis of oncocytoma were 21 % and 92 % at CT and 15 % and 90 % at MRI. SEI is not useful for the diagnosis of renal oncocytoma with CT or MRI. (orig.)

  8. MRI Diagnosis of abnormal meningeal enhancement%脑膜异常强化的MRI诊断

    Institute of Scientific and Technical Information of China (English)

    俞方荣; 王土兴; 方春; 朱翔

    2014-01-01

    目的:分析不同病变的脑膜异常强化MRI表现,探讨脑膜异常强化模式的形态与病因间的关系。方法对资料完整、MRI增强扫描显示脑膜异常强化的27例患者进行回顾性分析。结果27例患者中脑膜癌病11例(其中软脑膜强化模式9例,包括结节样强化4例、线样强化4例、结节样和线样强化并存的混合型强化1例,全脑膜强化模式、混合型强化2例);感染性脑膜炎9例(其中细菌性脑膜炎5例,包括软脑膜强化模式、线样强化4例,全脑膜强化模式、线样强化1例,并伴有硬膜下脓肿、颅骨骨髓炎,结核性脑膜炎3例,均为软脑膜强化模式,2例为线样强化,1例为结节样强化并伴有脑内多发结核结节,病毒性脑膜炎1例,为软脑膜强化模式、局限性线样强化);自发性低颅压综合征2例(硬脑膜强化模式、为弥漫均匀的线样强化);慢性硬膜下血肿4例和慢性硬膜下血肿伴硬膜下积液1例(硬脑膜强化模式、线样强化)。结论不同病变所致脑膜异常强化,其强化模式及形态具有一定的特点,MRI能为疾病的诊断提供重要信息。%Objective To analyze MRI findings of abnormal meningeal enhancement and to evaluate the relation between the patterns and shapes of abnormal meningeal enhancement and the causes of disease. Methods Twenty seven patients with abnormal meningeal enhancement on contrast enhanced MRI were included in the study. The patterns and shapes of abnormal meningeal enhancement on MRI in relation to clinical conditions were retrospectively analyzed. Results The diagnosis of 27 patients were meningeal carcinomatosis in 11 cases, infective meningitis in 9 cases (5 bacterial meningitis, 3 tuberculous menin-gitis and 1 viral meningitis), spontaneous intracranial hypotension syndromein in 2, chronic subdural hematoma in 4 and chronic subdural hematoma with subdural hydroma in 1. Meningeal

  9. Gadolinium-DTPA enhanced MRI with CHESS method for lumbar disc herniation; Visualization of affected nerve roots

    Energy Technology Data Exchange (ETDEWEB)

    Aota, Yoichi; Kumano, Kiyoshi; Hirabayashi, Shigeru; Ogawa, Yutaka; Yoshikawa, Koki (Kanto Rosai Hospital, Kawasaki, Kanagawa (Japan))

    1993-11-01

    A total of 34 DTPA-enhanced magnetic resonance imaging (MRI) studies were made pre- and/or post-operatively by using chemical shift selective method in 31 patients with lumbar disc herniation. DTPA enhancement was seen in affected nerve roots in 7 of 15 preoperative cases and 6 of 12 postoperative cases with unfavorable course. When straight leg raising test revealed severe stimulation to the lower extremity nerve roots (less than 45degree), affected nerve roots were significantly enhanced with DTPA. All enhanced sites, except for one of arachnoid inflammation, was most remarkably compressed by herniation. Edema within the affected nerve root would be detected by DTPA-enhanced MRI. (N.K.).

  10. DCEMRI.jl: a fast, validated, open source toolkit for dynamic contrast enhanced MRI analysis.

    Science.gov (United States)

    Smith, David S; Li, Xia; Arlinghaus, Lori R; Yankeelov, Thomas E; Welch, E Brian

    2015-01-01

    We present a fast, validated, open-source toolkit for processing dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data. We validate it against the Quantitative Imaging Biomarkers Alliance (QIBA) Standard and Extended Tofts-Kety phantoms and find near perfect recovery in the absence of noise, with an estimated 10-20× speedup in run time compared to existing tools. To explain the observed trends in the fitting errors, we present an argument about the conditioning of the Jacobian in the limit of small and large parameter values. We also demonstrate its use on an in vivo data set to measure performance on a realistic application. For a 192 × 192 breast image, we achieved run times of analysis package tested and produced comparable accuracy, even in the presence of noise.

  11. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study.

    Science.gov (United States)

    Rosales-Lagarde, Alejandra; Armony, Jorge L; Del Río-Portilla, Yolanda; Trejo-Martínez, David; Conde, Ruben; Corsi-Cabrera, Maria

    2012-01-01

    Converging evidence from animal and human studies suggest that rapid eye movement (REM) sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation (REM-D) on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI). Twenty healthy subjects were randomly assigned to two groups: selective REM-D, by awakening them at each REM sleep onset, or non-rapid eye movement sleep interruptions (NREM-I) as control for potential non-specific effects of awakenings and lack of sleep. In a within-subject design, a visual emotional reactivity task was performed in the scanner before and 24 h after sleep manipulation. Behaviorally, emotional reactivity was enhanced relative to baseline (BL) in the REM deprived group only. In terms of fMRI signal, there was, as expected, an overall decrease in activity in the NREM-I group when subjects performed the task the second time, particularly in regions involved in emotional processing, such as occipital and temporal areas, as well as in the ventrolateral prefrontal cortex, involved in top-down emotion regulation. In contrast, activity in these areas remained the same level or even increased in the REM-D group, compared to their BL level. Taken together, these results suggest that lack of REM sleep in humans is associated with enhanced emotional reactivity, both at behavioral and neural levels, and thus highlight the specific role of REM sleep in regulating the neural substrates for emotional responsiveness.

  12. Multiple arterial phase MRI of arterial hypervascular hepatic lesions: improved arterial phase capture and lesion enhancement.

    Science.gov (United States)

    Ikram, Nabia S; Yee, Judy; Weinstein, Stefanie; Yeh, Benjamin M; Corvera, Carlos U; Monto, Alexander; Hope, Thomas A

    2017-03-01

    To establish if triple-phase arterial imaging improves the detection of arterial phase hyperintense lesions based on arterial phase capture, motion artifact degradation, and lesion enhancement when compared to single-phase imaging. Patients at risk for hepatocellular carcinoma were imaged at 3.0T. Seventy-three consecutive patients with a standard single-phase MRI and eighty-five consecutive patients were imaged using extracellular contrast with triple arterial phase MRI using three sequential accelerated acquisitions of 8 s. Arterial phase capture and image quality were qualitatively categorized. Forty single-phase and forty-four triple-phase studies contained arterially enhancing lesions > 1 cm with washout appearance. The contrast-to-noise ratio (CNR) of the lesions was calculated. We compared the differences in means with Student t-tests and those in arterial phase capture with a Chi squared test with Yates correction. The triple-phase acquisitions captured the early or late arterial phases more frequently than did the single-phase acquisition (99% vs 86%; P value = 0.006). Triple-phase also provided greater number of patients with early or late arterial phase imaging without motion artifact (92% vs 79%, P-value = 0.05). The lesion analysis revealed increased maximum CNR in the triple-phase imaging (704.4) vs. single-phase imaging (517.2), P-value phase acquisition provides more robust arterial phase imaging for hepatic lesions, with increased lesion CNR, compared to standard single-phase arterial phase imaging.

  13. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study

    Science.gov (United States)

    Rosales-Lagarde, Alejandra; Armony, Jorge L.; del Río-Portilla, Yolanda; Trejo-Martínez, David; Conde, Ruben; Corsi-Cabrera, Maria

    2012-01-01

    Converging evidence from animal and human studies suggest that rapid eye movement (REM) sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation (REM-D) on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI). Twenty healthy subjects were randomly assigned to two groups: selective REM-D, by awakening them at each REM sleep onset, or non-rapid eye movement sleep interruptions (NREM-I) as control for potential non-specific effects of awakenings and lack of sleep. In a within-subject design, a visual emotional reactivity task was performed in the scanner before and 24 h after sleep manipulation. Behaviorally, emotional reactivity was enhanced relative to baseline (BL) in the REM deprived group only. In terms of fMRI signal, there was, as expected, an overall decrease in activity in the NREM-I group when subjects performed the task the second time, particularly in regions involved in emotional processing, such as occipital and temporal areas, as well as in the ventrolateral prefrontal cortex, involved in top-down emotion regulation. In contrast, activity in these areas remained the same level or even increased in the REM-D group, compared to their BL level. Taken together, these results suggest that lack of REM sleep in humans is associated with enhanced emotional reactivity, both at behavioral and neural levels, and thus highlight the specific role of REM sleep in regulating the neural substrates for emotional responsiveness. PMID:22719723

  14. Blunt splenic trauma: Can contrast enhanced sonography be used for the screening of delayed pseudoaneurysms?

    Energy Technology Data Exchange (ETDEWEB)

    Poletti, Pierre-Alexandre, E-mail: Pierre-Alexandre.Poletti@hcuge.ch [Department of Radiology, University Hospital of Geneva, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14 (Switzerland); Becker, Christoph D.; Arditi, Daniel; Terraz, Sylvain [Department of Radiology, University Hospital of Geneva, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14 (Switzerland); Buchs, Nicolas [Department of Surgery, University Hospital of Geneva, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14 (Switzerland); Shanmuganathan, Kathirkamanathan [Department of Diagnostic Radiology and Nuclear Medicine, 22 S. Greene Street, Baltimore, MD 21201 (United States); Platon, Alexandra [Department of Radiology, University Hospital of Geneva, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14 (Switzerland)

    2013-11-01

    Purpose: To assess the value of contrast-enhanced sonography (CES) for the detection of delayed post-traumatic splenic pseudo-aneurysms, usually considered an indication for angiographic embolization. Methods: Sixty-three consecutive hemodynamically stable trauma patients in whom admission CT displayed a splenic injury of grade II or higher (AAST classification), without evidence of vascular involvement, were included in the study. CES of the spleen using a second generation contrast agent was systematically performed within 48–72 h after admission, for the detection of a pooling of contrast media suggestive of pseudoaneurysm. Within 6 h after contrast-enhanced sonography, all patients underwent an abdominal CT for control purposes. CES results were compared to CT findings, which were considered the reference standard. This study received approval from the institutional ethical board. Results: CES showed a blush of contrast consistent with a pseudoaneurysm in 6 of the 63 patients. All were confirmed at subsequent control CT. Pooling of contrast was found at CT in 2 patients in whom contrast-enhanced sonography was negative. There was no false positive CES examination for the suspicion of pseudoaneurysms. When compared to CT, the sensitivity, specificity, positive and negative predictive values of CES to suggest a pseudoaneurysms, were 75% (6/8), 100% (55/55), 100% (6/6), and 96% (55/57), respectively. Conclusion: Our data suggest that CES may be useful for the screening of delayed traumatic splenic pseudoaneurysms: if a negative CES does not absolutely rule out a pseudoaneurysm, a positive CES warrants an angiography, without need of control CT.

  15. Blunt splenic trauma: can contrast enhanced sonography be used for the screening of delayed pseudoaneurysms?

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Becker, Christoph D; Arditi, Daniel; Terraz, Sylvain; Buchs, Nicolas; Shanmuganathan, Kathirkamanathan; Platon, Alexandra

    2013-11-01

    To assess the value of contrast-enhanced sonography (CES) for the detection of delayed post-traumatic splenic pseudo-aneurysms, usually considered an indication for angiographic embolization. Sixty-three consecutive hemodynamically stable trauma patients in whom admission CT displayed a splenic injury of grade II or higher (AAST classification), without evidence of vascular involvement, were included in the study. CES of the spleen using a second generation contrast agent was systematically performed within 48-72 h after admission, for the detection of a pooling of contrast media suggestive of pseudoaneurysm. Within 6h after contrast-enhanced sonography, all patients underwent an abdominal CT for control purposes. CES results were compared to CT findings, which were considered the reference standard. This study received approval from the institutional ethical board. CES showed a blush of contrast consistent with a pseudoaneurysm in 6 of the 63 patients. All were confirmed at subsequent control CT. Pooling of contrast was found at CT in 2 patients in whom contrast-enhanced sonography was negative. There was no false positive CES examination for the suspicion of pseudoaneurysms. When compared to CT, the sensitivity, specificity, positive and negative predictive values of CES to suggest a pseudoaneurysms, were 75% (6/8), 100% (55/55), 100% (6/6), and 96% (55/57), respectively. Our data suggest that CES may be useful for the screening of delayed traumatic splenic pseudoaneurysms: if a negative CES does not absolutely rule out a pseudoaneurysm, a positive CES warrants an angiography, without need of control CT. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. 超声造影与增强 MRI 在眼眶肿瘤中的应用价值%Value of contrast-enhanced ultrasound and enhancement MRI in differetial diagnosis of the orbital neoplasms

    Institute of Scientific and Technical Information of China (English)

    李蓬; 陈樱; 武犁; 陈文卫; 黄星月

    2015-01-01

    Objective To evaluate the ability of contrast-enhanced ultrasonography (CEUS ) compared to enhanced MRI scan in differential diagnosis of benign and malign tumor of orbit.Methods CEUS and enhanced MRI was performed in 74 patients with tumor of orbit.These patients were divided into two groups:benign and malignant tumor depended on histological diagnosis.The results were analysed with SonoLiver software.The coincidence rate of diagnosis and enhancement intensity among CEUS,MRI and CEUS+ MRI were compared and the quantitative parameters of CEUS were analysed.Results (1 )The diagnostic accordance rate of benign group by three methods were 90.0%,80.0% and 96.0% respectively, there was statistical difference for diagnostic coincidence rate between the MRI and CEUS+ MRI(P 0.05 ).(2 )The enhancement intensity of CEUS was different between benign and malignant groups (P 0.05).(3)The parameters of tumor imaging obtained time intensity curve(TIC):rise time (RT),half elution time and time to peaking (TTP)were significantly different between benign and malignant groups(P 0.05).Conclusions CEUS had higher diagnostic accuracy than MRI in benign orbital tumor.The contrast enhancement intensity and time-intensity curves provide valuable diagnostic information for differential diagnosis of benign and malignant orbital tumor.%目的:探讨超声造影与增强 MRI 两种方法在眼眶良恶性肿瘤鉴别诊断中的应用价值。方法选取74例眼眶占位患者(74只眼),以病理诊断为金标准分为良性组和恶性组。行超声造影检查,所得图像资料导入 SonoLiver 软件进行分析。比较超声造影、增强 MRI 及联合诊断(超声造影+增强MRI)3种方法的诊断符合率及增强强度差异,分析超声造影定量参数指标。结果(1)良性组中上述3种方法的诊断符合率分别为90.0%、80.0%、96.0%,两两比较仅增强 MRI 与联合诊断两者间差异有统计学意义(P 0.05)。(2)超声造影的增强强度在良恶

  17. Imaging corticospinal tract connectivity in injured rat spinal cord using manganese-enhanced MRI

    Directory of Open Access Journals (Sweden)

    Bilgen Mehmet

    2006-11-01

    Full Text Available Abstract Background Manganese-enhanced MRI (MEI offers a novel neuroimaging modality to trace corticospinal tract (CST in live animals. This paper expands this capability further and tests the utility of MEI to image axonal fiber connectivity in CST of injured spinal cord (SC. Methods A rat was injured at the thoracic T4 level of the SC. The CST was labeled with manganese (Mn injected intracortically at two weeks post injury. Next day, the injured SC was imaged using MEI and diffusion tensor imaging (DTI modalities. Results In vivo MEI data obtained from cervical SC confirmed that CST was successfully labeled with Mn. Ex vivo MEI data obtained from excised SC depicted Mn labeling of the CST in SC sections caudal to the lesion, which meant that Mn was transported through the injury, possibly mediated by viable CST fibers present at the injury site. Examining the ex vivo data from the injury epicenter closely revealed a thin strip of signal enhancement located ventrally between the dorsal horns. This enhancement was presumably associated with the Mn accumulation in these intact fibers projecting caudally as part of the CST. Additional measurements with DTI supported this view. Conclusion Combining these preliminary results collectively demonstrated the feasibility of imaging fiber connectivity in experimentally injured SC using MEI. This approach may play important role in future investigations aimed at understanding the neuroplasticity in experimental SCI research.

  18. Assessment of metastatic liver disease in patients with primary extrahepatic tumors by contrast-enhanced sonography versus CT & MRI

    NARCIS (Netherlands)

    Dietrich, Christoph F.; Kratzer, Wolfgang; Strobel, Deike; Danse, Etienne; Fessl, Robert; Bunk, Alfred; Vossas, Udo; Hauenstein, Karlheinz; Koch, Wilhelm; Blank, Wolfgang; Oudkerk, Matthijs; Hahn, Dietbert; Greis, Christian

    2006-01-01

    AIM: To evaluate contrast-enhanced ultrasonography (CEUS) using SonoVue (R) in the detection of liver metastases in patients with known extrahepatic primary tumors versus the combined gold standard comprising CT, MRI and clinical/histological data. METHODS: It is an international multicenter study,

  19. Gadoxetic acid-enhanced MRI and diffusion-weighted imaging for the detection of colorectal liver metastases after neoadjuvant chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mi Hye [Konkuk University Medical Center, Department of Radiology, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Joon Koo; Choi, Byung-Ihn [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Hur, Bo Yun [Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Kim, Tae-You [Seoul National University Hospital, Department of Internal Medicine, Seoul (Korea, Republic of); Jeong, Seung-Yong; Yi, Nam-Joon; Suh, Kyung-Suk [Seoul National University Hospital, Department of Surgery, Seoul (Korea, Republic of)

    2015-08-15

    To investigate the diagnostic performance of gadoxetic acid-enhanced MRI including diffusion-weighted imaging (DWI) for the detection of colorectal liver metastases (CRLMs) after neoadjuvant chemotherapy (NAC). Our study population comprised 77 patients with 140 CRLMs who underwent gadoxetic acid-enhanced MRI within 1 month prior to surgery: group A (without NAC, n = 38) and group B (with NAC, n = 39). Two radiologists independently assessed all MR images and graded their diagnostic confidence for CRLM on a 5-point scale. Diagnostic accuracy, sensitivity and positive predictive values (PPV) were calculated and compared between the two groups. Diagnostic accuracy of gadoxetic acid-enhanced MRI in group B was slightly lower than in group A, but a statistically significant difference was not observed (observer 1: A{sub z}, 0.926 in group A, 0.905 in group B; observer 2: A{sub z}, 0.944 in group A, 0.885 in group B; p > 0.05). Sensitivity and PPV of group B were comparable to those of group A (observer 1: sensitivity = 93.5 % vs. 93.6 %, PPV = 95.1 % vs. 86.9 %; observer 2: sensitivity = 96.8 % vs. 91.0 %; PPV = 90.0 % vs. 89.7 %; all p > 0.05). Gadoxetic acid-enhanced MRI including DWI provided good diagnostic performance with high sensitivity (>90 %) for the detection of CRLMs, regardless of the influence of NAC. (orig.)

  20. Quantification of myocardial delayed enhancement and wall thickness in hypertrophic cardiomyopathy: Multidetector computed tomography versus magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Lei [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Rd Beijing (China); Ma, Xiaohai, E-mail: maxi8238@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Rd Beijing (China); Feuchtner, Gudrun Maria [Department of Radiology II, Innsbruck Medical University, Innsbruck (Austria); Zhang, Chen; Fan, Zhanming [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Rd Beijing (China)

    2014-10-15

    Objectives: To evaluate the accuracy of multidetector computed tomography (MDCT) in assessing myocardial delayed enhancement and left ventricle wall thickness in hypertrophic cardiomyopathy (HCM) compared with cardiac magnetic resonance (CMR) as the reference standard. Materials and methods: Eighty consecutive patients (59 male; 53.2 ± 13.0 years) were examined with MDCT, followed by CMR 1 day later. Cardiac CT angiography and a delayed CT were performed. CMR was performed according to a standardized protocol. Left ventricle wall thickness and positions of myocardial delayed enhancement were identified in both CMR and CT images according to the American Heart Association left ventricle 17-segment model. Myocardial delayed enhancement was characterized as “dense” (areas with clear defined borders) or “diffuse” and then quantified using both techniques. Results: Left ventricle wall thickness determined by MDCT was significantly correlated with CMR (R = 0.88, P < 0.01). Compared with CMR, MDCT accurately diagnosed 74 of 78 (94.9%) patients and 1243 of 1326 (93.7%) segments. For dense myocardial delayed enhancement, MDCT significantly correlated with CMR (R = 0.88, P < 0.01) and slightly underestimated myocardial delayed enhancement (mean, −3.85%; lower and upper limits of agreement, −13.40% and 5.70%, respectively). Conclusions: MDCT provides reliable quantification of myocardial delayed enhancement and evaluation of left ventricle wall thickness and has a good correlation with CMR in patients with HCM when a comprehensive cardiac CT protocol is used and can be applied for intervention planning.

  1. Gadolinium-enhanced MRI features of acute gouty arthritis on top of chronic gouty involvement in different joints.

    Science.gov (United States)

    Emad, Yasser; Ragab, Yasser; El-Naggar, Ahmed; El-Shaarawy, Nashwa; Abd-Allah, Mayada A; Gamal, Rania M; Fathy, Ahmed; Hawass, Mona; Rasker, Johannes J

    2015-11-01

    The aims of the current study are to describe gadolinium-enhanced MRI features of an acute flare of established gouty arthritis in different joints and to examine a possible association between serum uric acid and MRI signs indicative of ongoing inflammation and/or structural joint damage as well as association with disease characteristics and laboratory findings. Twenty-seven male patients with established chronic gout agreed to participate, mean age 47.6 years, and mean disease duration in months 43.2 (±31.8). For all patients, detailed demographic, disease characteristics, and laboratory findings were obtained and correlated with MRI findings. In 27 patients with established gout, a total of 50 MRI studies were performed of the following joints: feet joints (n = 23), ankles (n = 18), knees (n = 5), and hand and wrist joints (n = 4). MRI revealed capsular thickening in 19 patients, bone marrow edema (BME) in 15, soft tissue edema (STE) in 20, joint effusion in 21, bone erosions in 17, cartilaginous erosions in 4, and tenosynovitis in 9 cases. In 17 cases, tophaceous lesions were found. Post contrast MRI showed synovial thickening in seven cases. Positive correlations were observed between serum uric acid levels and the following MRI findings: capsular thickening (r = 0.552, p = 0.003), BME (r = 0.668, p ≤ 0.0001), STE (r = 0.559, p = 0.002), and tenosynovitis (r = 0.513, p = 0.006). Using MRI in chronic gout, important features can be detected like BME, minute cartilaginous erosions, and hypertrophic synovial inflammation in post contrast MR images. Serum uric acid (SUA) was positively correlated with capsular thickening, BME, STE, and tenosynovitis.

  2. Delay Analysis of an Enhancing IEEE 802.11 Point Coordination Function MAC Protocol

    Directory of Open Access Journals (Sweden)

    Zheng Guan

    2014-05-01

    Full Text Available The widespread use of multimedia networking applications has brought more requirements to the network, creating a need for end-to-end Quality of Service (QoS. The contention-free Point Coordination Function (PCF with Round Robin scheme, where the Access Point controls all transmissions based on a polling mechanism, is defined in IEEE 802.11 standard to provide QoS service. This network suffers from inefficiency in the delay sensitive traffic and makes. It is difficult to provide priority-differentiated service. In this paper, a useful enhance mechanism is derived from a two-level-polling model with a parallel scheme between the polling and switch over processes. We consider two different polling schemes according to station classify: key station and normal station. This mechanism allows for a delay guarantee as well as priority service. An analytical is developed for evaluating the queuing length for the station and waiting time for the packets at nodes. Based on this model, we achieve several closed-form expressions for mean cycle time, mean queue length and mean waiting time. To verify the correctness of our analytical model, we also develop a simulator for the 802.11 PCF MAC. The simulation results well match the analytical results.

  3. Adaptive Transmitter Optimization in Multiuser Multiantenna Systems: Theoretical Limits, Effect of Delays, and Performance Enhancements

    Directory of Open Access Journals (Sweden)

    Samardzija Dragan

    2005-01-01

    Full Text Available The advances in programmable and reconfigurable radios have rendered feasible transmitter optimization schemes that can greatly improve the performance of multiple-antenna multiuser systems. Reconfigurable radio platforms are particularly suitable for implementation of transmitter optimization at the base station. We consider the downlink of a wireless system with multiple transmit antennas at the base station and a number of mobile terminals (i.e., users each with a single receive antenna. Under an average transmit power constraint, we consider the maximum achievable sum data rates in the case of (1 zero-forcing (ZF spatial prefilter, (2 modified zero-forcing (MZF spatial prefilter, and (3 triangularization spatial prefilter coupled with dirty-paper coding (DPC transmission scheme. We show that the triangularization with DPC approaches the closed-loop MIMO rates (upper bound for higher SNRs. Further, the MZF solution performs very well for lower SNRs, while for higher SNRs, the rates for the ZF solution converge to the MZF rates. An important impediment that degrades the performance of such transmitter optimization schemes is the delay in channel state information (CSI. We characterize the fundamental limits of performance in the presence of delayed CSI and then propose performance enhancements using a linear MMSE predictor of the CSI that can be used in conjunction with transmitter optimization in multiple-antenna multiuser systems.

  4. Agreement of left ventricular mass in steady state free precession and delayed enhancement MR images: implications for quantification of fibrosis in congenital and ischemic heart disease

    Directory of Open Access Journals (Sweden)

    Olivecrona Goran

    2010-01-01

    Full Text Available Abstract Background Left ventricular mass (LVM is used when expressing infarct or fibrosis as a percentage of the left ventricle (LV. Quantification of LVM is interchangeably carried out in cine steady state free precession (SSFP and delayed enhancement (DE magnetic resonance imaging (MRI. However, these techniques may yield different LVM. Therefore, the aim of the study was to compare LVM determined by SSFP and DE MRI in patients and determine the agreement with these sequences with ex vivo data in an experimental animal model. Methods Ethics committees approved human and animal studies. Informed written consent was obtained from all patients. SSFP and DE images were acquired in 60 patients (20 with infarction, 20 without infarction and 20 pediatric patients. Ex vivo MRI was used as reference method for LVM in 19 pigs and compared to in vivo SSFP and DE. Results LVM was greater in SSFP than in DE (p 2 = 0.98, and a bias of 7.3 ± 6.7% (p 2 = 0.83. Bias for SSFP and DE images compared to ex vivo LVM was -0.2 ± 9.0% and -7.7 ± 8.5% respectively. Conclusions LVM was higher when measured with SSFP compared to DE. Thus, the percentage infarction of the LV will differ if SSFP or DE is used to determine LVM. There was no significant difference between SSFP and ex vivo LVM suggesting that SSFP is more accurate for LVM quantification. To avoid intrinsic error due to the differences between the sequences, we suggest using DE when expressing infarct as a percentage of LVM.

  5. Preoperative evaluation of colorectal liver metastases: comparison between gadoxetic acid-enhanced 3.0-T MRI and contrast-enhanced MDCT with histopathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Scharitzer, M.; Ba-Ssalamah, A.; Ringl, H.; Koelblinger, C.; Weber, M. [Medical University of Vienna, Department of Radiology, Vienna (Austria); Gruenberger, T. [Medical University of Vienna, Department of Surgery, Vienna (Austria); Schima, W. [Department of Radiology, KH Goettlicher Heiland, KH der Barmherzigen Schwestern and St Josef-Krankenhaus, Vienna (Austria)

    2013-08-15

    The aim of this prospective study was to compare the diagnostic performance of 64-row MDCT and gadoxetic-acid-enhanced MRI at 3.0 T in patients with colorectal liver metastases in correlation with histopathological findings. Lesions detected at MDCT and MRI were interpreted by three blinded readers and compared with histopathological workup as the term of reference. Two subgroups of lesions were additionally evaluated: (1) metastases smaller than 10 mm and (2) lesions in patients with and without steatosis of the liver, assessed histopathologically. Surgery and histopathological workup revealed 81 colorectal liver metastases in 35 patients and diffuse metastatic involvement in 3 patients. In a lesion-by-lesion analysis, significant sensitivity differences could only be found for reader 1 (P = 0.035) and reader 3 (P = 0.003). For segment-based evaluation, MRI was more sensitive only for reader 3 (P = 0.012). The number of false-positive results ranged from 3 to 12 for MDCT and 8 to 11 for MRI evaluation. In the group of small lesions, the sensitivity differed significantly between both methods (P = 0.003). In patients with hepatic steatosis, MRI showed a trend toward better performance than MDCT, but without statistical performance. The 3.0-T MRI with liver-specific contrast agents is the preferred investigation in the preoperative setting, especially for the assessment of small colorectal liver metastases. (orig.)

  6. Availability of Gd-DTPA enhanced MRI for lumbar disc herniation; Mechanism enhancing scar tissue around herniated disc and its meaning

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Chisato; Yoshizawa, Hidezo; Nakai, Sadaaki; Kobayashi, Shigeru; Morita, Tomofumi; Kojima, Motohiro (Fujita Health Univ., Toyoake, Aichi (Japan))

    1994-05-01

    Extradural scar tissue arising between the herniated disk in the lumbar spine and its surrounding tissue was examined in 44 patients with lumbar disc herniation, using Gd-DTPA enhanced magnetic resonance imaging (MRI). Findings of enhanced MRI were divided into three types: that is, type 1 in which the surrounding of the herniated disk was not enhanced; type 2 in which it was partially enhanced; type 3 in which it was entirely enhanced. Of these 44 patients, 15 (34.1%) had type I, 22 (50.0%) had type 2 and 7 (15.9%) had type 3. Extradural scar tissue was seen as high signal intensity on T1-weighted images in 66%, revealing the extent of nerve root compression. Furthermore, 18 of the 44 patients underwent surgery and surgical findings were compared with types of MRI findings. According to MRI findings, these 18 patients consisted of 2 with type 1, 11 with type 2, and 5 with type 3. The two type 1 patients had subligamentous type; 9 type 2 patients had subligamentous type and the other 2 had transligamentous type; and the 5 type 3 patients had all sequestration type. Extradural scar tissue was microscopically shown to be composed of collagenic fibers containing many vessels and to be leakily neovascular structure associated with gap junction and fenestra. Enhanced MRI was capable of delineating the proliferation of extradural scar tissue surrounding the herniated disk easily, thus allowing the determination of pathological changes arising between the herniated disc and nerve root. (N.K.).

  7. Pulmonary Arterial Hypertension: Use of Delayed Contrast-Enhanced Cardiovascular Magnetic Resonance in Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bessa, Luiz Gustavo Pignataro, E-mail: lgpignataro@ig.com.br; Junqueira, Flávia Pegado; Bandeira, Marcelo Luiz da Silva; Garcia, Marcelo Iorio; Xavier, Sérgio Salles; Lavall, Guilherme; Torres, Diego; Waetge, Daniel [Hospital Universitário Clementino Fraga Filho, Ilha do Fundão, RJ (Brazil)

    2013-10-15

    Pulmonary arterial hypertension is a severe and progressive disease. Its early diagnosis is the greatest clinical challenge. To evaluate the presence and extension of the delayed myocardial contrast-enhanced cardiovascular magnetic resonance, as well as to verify if the percentage of the myocardial fibrosis mass is a severity predictor. Cross-sectional study with 30 patients with pulmonary arterial hypertension of groups I and IV, subjected to clinical, functional and hemodynamic evaluation, and to cardiac magnetic resonance. The mean age of patients was 52 years old, with female predominance (77%). Among the patients, 53% had right ventricular failure at diagnosis, and 90% were in functional class II/III. The mean of the 6-minute walk test was 395m. In hemodynamic study with right catheterism, the mean average pulmonary arterial pressure was 53.3mmHg, of the cardiac index of 2.1L/ min.m{sup 2}, and median right atrial pressure was 13.5 mmHg. Delayed myocardial contrast enhanced cardiovascular magnetic resonance was found in 28 patients. The mean fibrosis mass was 9.9 g and the median percentage of fibrosis mass was 6.17%. The presence of functional class IV, right ventricular failure at diagnosis, 6-minute walk test < 300 meters and right atrial pressure ≥ 15 mmHg, with cardiac index < 2.0 L/ min.m{sup 2}, there was a relevant association with the increased percentage of myocardial fibrosis. The percentage of the myocardial fibrosis mass indicates a non-invasive marker with promising perspectives in identifying patients with high risk factors for pulmonary hypertension.

  8. Pulmonary Arterial Hypertension: Use of Delayed Contrast-Enhanced Cardiovascular Magnetic Resonance in Risk Assessment

    Science.gov (United States)

    Bessa, Luiz Gustavo Pignataro; Junqueira, Flávia Pegado; Bandeira, Marcelo Luiz da Silva; Garcia, Marcelo Iorio; Xavier, Sérgio Salles; Lavall, Guilherme; Torres, Diego; Waetge, Daniel

    2013-01-01

    Background Pulmonary arterial hypertension is a severe and progressive disease. Its early diagnosis is the greatest clinical challenge. Objective To evaluate the presence and extension of the delayed myocardial contrast-enhanced cardiovascular magnetic resonance, as well as to verify if the percentage of the myocardial fibrosis mass is a severity predictor. Methods Cross-sectional study with 30 patients with pulmonary arterial hypertension of groups I and IV, subjected to clinical, functional and hemodynamic evaluation, and to cardiac magnetic resonance. Results The mean age of patients was 52 years old, with female predominance (77%). Among the patients, 53% had right ventricular failure at diagnosis, and 90% were in functional class II/III. The mean of the 6-minute walk test was 395m. In hemodynamic study with right catheterism, the mean average pulmonary arterial pressure was 53.3mmHg, of the cardiac index of 2.1L/ min.m2, and median right atrial pressure was 13.5 mmHg. Delayed myocardial contrast enhanced cardiovascular magnetic resonance was found in 28 patients. The mean fibrosis mass was 9.9 g and the median percentage of fibrosis mass was 6.17%. The presence of functional class IV, right ventricular failure at diagnosis, 6-minute walk test < 300 meters and right atrial pressure ≥ 15 mmHg, with cardiac index < 2.0 L/ min.m2, there was a relevant association with the increased percentage of myocardial fibrosis. Conclusion The percentage of the myocardial fibrosis mass indicates a non-invasive marker with promising perspectives in identifying patients with high risk factors for pulmonary hypertension. PMID:23979779

  9. A Combination of Restoration, Enhancement and Skull Stripping for Brain MRI

    Directory of Open Access Journals (Sweden)

    S. Madhukumar

    2015-02-01

    Full Text Available The preprocessing steps have substantial influence on the accuracy of segmentation and classification of lesions. The background on the image grid, behind the brain structures in the MRI images may not be always homogeneous. The edges or sharp pixel intensity transitions present in the back ground may get preserved during edge sensitive noise restoration and highlighted during contrast enhancement. If conventional noise restoration methods as Gaussian Kernels are adopted, the weak edges of lesions and structures get smoothened. Similarly, common contrast enhancement schemes like Global/Local histogram equalization either over saturate the image or degrade the textural, intensity and geometrical features of the image above tolerable limit. This study proposes a novel combination of preprocessing methods which is exclusively suitable for MR images carrying weak edges. The proposed combination of preprocessing comprises back ground elimination, restoration with bilateral filter, enhancement with Contrast Limited Adaptive Histogram Equalization (CLAHE and skull stripping. Back ground elimination and skull stripping are performed by multiplying the original image and contrast enhanced image respectively with a multiplication mask. Multiplication mask for background elimination is generated by gradient based thresholding and a series of morphological operations and the multiplication mask for skull stripping is generated via adaptive Otzu’s thresholding. MR images of tumor edema complex are used for testing the proposed strategy. The method is experimented in Matlab®. Qualitative inspection of the skull stripped images reveals that the weak edges of tumor-focus and perifocal edema are well preserved, inhomogeneity in the uniform regions is suppressed, CLAHE do not alter the textural intensity and geometrical image features and the brain region is accurately extracted.

  10. Changes underlying the dynamic contrast-enhanced MRI response to treatment in rheumatoid arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, Richard J. [University of Liverpool, MARIARC, Liverpool (United Kingdom); Barnes, Theresa; Moots, Robert [University of Aintree, Clinical Rheumatology, School of Clinical Sciences, Liverpool (United Kingdom); Connolly, Sylvia [Whiston Hospital, Merseyside (United Kingdom); Eyes, Brian [University Hospital Aintree, Liverpool (United Kingdom); Campbell, Robert S.D. [Royal Liverpool Hospital, Liverpool (United Kingdom)

    2008-03-15

    Dynamic contrast-enhanced MRI of patients with rheumatoid arthritis has shown a decrease in the early enhancement rate (EER) of synovitis after treatment. The purpose of this work was to investigate the underlying changes. 3D dynamic contrast-enhanced images were acquired from 13 patients before and 1-2 weeks after anti-TNF{alpha} treatment. The EER of the inflamed synovium was measured. The T{sub 1} relaxation time of the synovitis was calculated from images at different flip angles. The time course of the arrival of gadolinium at the radial artery was determined. The gadolinium enhancement of the inflamed synovium was modeled to calculate the fractional plasma volume (v{sub p}), the fractional extravascular, extracellular fluid volume (v{sub e}), and the volume transfer constant (K{sup trans}). Pre- and post-treatment values were compared and the dependence of the EER on each parameter was assessed. There was a decrease in the EER measured over 26 s after treatment (29%, p = 0.002). Reductions in T{sub 1} (12%, p = 0.001), K{sup trans} (31%, p = 0.002), and v{sub p} (43%, p = 0.01) contributed to this; however, the EER was relatively insensitive to changes in v{sub e}. The decrease in EER after anti-TNF{alpha} treatment is largely caused by reductions in the volume transfer constant K{sup trans}, the fractional plasma volume v{sub p}, and the T{sub 1} relaxation time. Only the contributions from K{sup trans} and v{sub p} directly reflect synovial vascularity. (orig.)

  11. Discriminant analysis to classify glioma grading using dynamic contrast-enhanced MRI and immunohistochemical markers

    Energy Technology Data Exchange (ETDEWEB)

    Awasthi, Rishi [Sanjay Gandhi Post Graduate Institute of Medical Sciences, Department of Radiodiagnosis, Lucknow (India); Rathore, Ram K.S.; Sahoo, Prativa [Indian Institute of Technology, Department of Mathematics and Statistics, Kanpur (India); Soni, Priyanka; Husain, Nuzhat [Chhatrapati Sahuji Maharj Medical University, Department of Pathology, Lucknow (India); Awasthi, Ashish; Pandey, Chandra M. [Sanjay Gandhi Post Graduate Institute of Medical Sciences, Department of Biostatistics, Lucknow (India); Behari, Sanjay; Singh, Rohit K. [Sanjay Gandhi Post Graduate Institute of Medical Sciences, Department of Neurosurgery, Lucknow (India); Gupta, Rakesh K. [Sanjay Gandhi Post Graduate Institute of Medical Sciences, MR Section, Department of Radiodiagnosis, Lucknow, UP (India)

    2012-03-15

    The purpose of the present study was to look for the possible predictors which might discriminate between high- and low-grade gliomas by pooling dynamic contrast-enhanced (DCE)-perfusion derived indices and immunohistochemical markers. DCE-MRI was performed in 76 patients with different grades of gliomas. Perfusion indices, i.e., relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), permeability (k{sup trans} and k{sub ep}), and leakage (v{sub e}) were quantified. MMP-9-, PRL-3-, HIF-1{alpha}-, and VEGF-expressing cells were quantified from the excised tumor tissues. Discriminant function analysis using these markers was used to identify discriminatory variables using a stepwise procedure. To look for correlations between immunohistochemical parameters and DCE metrics, Pearson's correlation coefficient was also used. A discriminant function for differentiating between high- and low-grade tumors was constructed using DCE-MRI-derived rCBV, k{sub ep}, and v{sub e}. The form of the functions estimated are ''D{sub 1} = 0.642 x rCBV + 0.591 x k{sub ep} - 1.501 x v{sub e} - 1.550'' and ''D{sub 2} = 1.608 x rCBV + 3.033 x k{sub ep} + 5.508 x v{sub e} - 8.784'' for low- and high-grade tumors, respectively. This function classified overall 92.1% of the cases correctly (89.1% high-grade tumors and 100% low-grade tumors). In addition, VEGF expression correlated with rCBV and rCBF, whereas MMP-9 expression correlated with k{sub ep}. A significant positive correlation of HIF-1{alpha} with rCBV and VEGF expression was also found. DCE-MRI may be used to differentiate between high-grade and low-grade brain tumors non-invasively, which may be helpful in appropriate treatment planning and management of these patients. The correlation of its indices with immunohistochemical markers suggests that this imaging technique is useful in tissue characterization of gliomas. (orig.)

  12. Late gadolinium enhancement and subclinical cardiac dysfunction on cardiac MRI in asymptomatic HIV-positive men

    Directory of Open Access Journals (Sweden)

    A Loy

    2012-11-01

    Full Text Available Background: HIV is associated with an increased risk of cardiovascular disease (CVD and related clinical events. While traditional risk factors play an important role in the pathology of cardiovascular disease, HIV infection and its sequelae of immune activation and inflammation may have significant effects on the myocardium before becoming clinically evident. Cardiac MRI (CMR can be used to detect the pattern of these subclinical changes. This will lead to a better understanding of risk factors contributing to cardiovascular disease prior to it becoming clinically significant in HIV-positive patients. Methods: Prospective cohort study of 127 asymptomatic HIV-positive men on ART compared to 35 matched controls. Baseline demographics, HIV parameters, 12-lead ECG, routine biochemistry, and traditional cardiovascular risk factors were recorded. Images were acquired on a 3T Achieva Philips MRI scanner with 5 channel phase array cardiac coil and weight-based IV gadolinium was given at 0.15 mmol/kg dose with post-contrast inversion recovery imaging after 10 minutes. Results: 6/127 (4.7% of asymptomatic HIV-positive men had late gadolinium enhancement (LGE on MRI verses 1/35 (2.9% in the control group. In 3/6 (50% of cases this was in a classical infarction pattern with subendocardial involvement. 3/6 (50% were consistent with prior myocarditis. There was no significant difference in mean LVEF (66.93% vs 65.18%, LVMI (60.05g/m2 vs 55.94g/m2 or posterolateral wall thickness (8.28 mm and 8.16 mm between cases and controls respectively. There was significantly more diastolic dysfunction, E:A ratio < 1, found in the HIV-positive group, 18% vs 7% of controls (p = 0.037. Framingham risk did not predict either of these outcomes. Conclusions: There is an increased incidence of LGE detected on CMR in this asymptomatic HIV-positive cohort. Two distinct pathological processes were identifed as causing these changes, myocardial infarction and myocarditis

  13. MRI changes in myocarditis - Evaluation with spin echo, cine MR angiography and contrast enhanced spin echo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Roditi, Giles H.; Hartnell, George G.; Cohen, Mylan C

    2000-10-01

    AIM: Myocarditis is probably under-diagnosed with clinical criteria generally used for diagnosis. Magnetic resonance imaging (MRI) has shown promise in detecting heart muscle disorders and we set out to assess the role of cine magnetic resonance angiography (MRA) and contrast enhancement in myocarditis, as there is a need for a non-invasive tool that can aid prognosis and follow-up. MATERIALS AND METHODS: Twenty patients were evaluated with T1 SE pre- and post-gadolinium enhancement and cine MRA. Four patients were histologically proven to have myocarditis, eight others were diagnosed as having myocarditis by clinical criteria and eight did not have myocarditis. Images were evaluated in a blinded fashion for regional wall motion abnormality and contrast enhancement pattern. Analysis of contrast enhancement by signal intensity measurement was also performed. RESULTS: Focal myocardial enhancement with associated regional wall motion abnormality correlated with myocarditis in 10 out of 12 patients, two patients with abnormal focal enhancement alone also clinically had myocarditis. None of the non-myocarditis patients showed abnormal focal enhancement. Enhancement analysis suggests that focal corrected myocardial enhancement of > 40% is abnormal. CONCLUSION: In the correct clinical context, focal myocardial enhancement on spin echo MRI strongly supports a diagnosis of myocarditis, especially when associated with regional wall motion abnormality. Roditi, G.H. (2000)

  14. Contrast-enhanced CT- and MRI-based perfusion assessment for pulmonary diseases: basics and clinical applications.

    Science.gov (United States)

    Ohno, Yoshiharu; Koyama, Hisanobu; Lee, Ho Yun; Miura, Sachiko; Yoshikawa, Takeshi; Sugimura, Kazuro

    2016-01-01

    Assessment of regional pulmonary perfusion as well as nodule and tumor perfusions in various pulmonary diseases are currently performed by means of nuclear medicine studies requiring radioactive macroaggregates, dual-energy computed tomography (CT), and dynamic first-pass contrast-enhanced perfusion CT techniques and unenhanced and dynamic first-pass contrast enhanced perfusion magnetic resonance imaging (MRI), as well as time-resolved three-dimensional or four-dimensional contrast-enhanced magnetic resonance angiography (MRA). Perfusion scintigraphy, single-photon emission tomography (SPECT) and SPECT fused with CT have been established as clinically available scintigraphic methods; however, they are limited by perfusion information with poor spatial resolution and other shortcomings. Although positron emission tomography with 15O water can measure absolute pulmonary perfusion, it requires a cyclotron for generation of a tracer with an extremely short half-life (2 min), and can only be performed for academic purposes. Therefore, clinicians are concentrating their efforts on the application of CT-based and MRI-based quantitative and qualitative perfusion assessment to various pulmonary diseases. This review article covers 1) the basics of dual-energy CT and dynamic first-pass contrast-enhanced perfusion CT techniques, 2) the basics of time-resolved contrast-enhanced MRA and dynamic first-pass contrast-enhanced perfusion MRI, and 3) clinical applications of contrast-enhanced CT- and MRI-based perfusion assessment for patients with pulmonary nodule, lung cancer, and pulmonary vascular diseases. We believe that these new techniques can be useful in routine clinical practice for not only thoracic oncology patients, but also patients with different pulmonary vascular diseases.

  15. Plasma exchange combined with azathioprine in multiple sclerosis using serial gadolinium-enhanced MRI to monitor disease activity: a randomized single-masked cross-over pilot study

    DEFF Research Database (Denmark)

    Sørensen, P.S.; Wanscher, B; Szpirt, W

    1996-01-01

    the whole trial, and three patients discontinued the trial, two during the run-in period of azathioprine treatment and one at the introduction of PE. The primary efficacy variables were the number of gadolinium-enhancing lesions and the occurrence of new enhancing lesions on serial MRI performed every 3...... weeks during the PE and the control period. Secondary efficacy variables were the total MS lesion load on T2-weighted MRI, multimodal evoked potentials, and clinical neurologic ratings. No significant differences were found regarding the number of enhancing lesions or occurrence of new enhancing lesions...... in the two periods. Although the total MS lesion load on MRI was significantly lower (p

  16. Value of retrospective image fusion of {sup 18}F-FDG PET and MRI for preoperative staging of head and neck cancer: Comparison with PET/CT and contrast-enhanced neck MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kanda, Tomonori [Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan); Department of Radiology, Hyogo Cancer Center, Hyogo (Japan); Kitajima, Kazuhiro, E-mail: kitajima@med.kobe-u.ac.jp [Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan); Suenaga, Yuko; Konishi, Jyunya [Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan); Sasaki, Ryohei [Division of Radiation Oncology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan); Morimoto, Koichi; Saito, Miki; Otsuki, Naoki; Nibu, Ken-ichi [Department of Otolaryngology-Head and Neck Surgery, Kobe University Graduate School of Medicine, Kobe (Japan); Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, Kobe (Japan)

    2013-11-01

    Purpose: To assess the clinical value of retrospective image fusion of neck MRI and {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) PET for locoregional extension and nodal staging of neck cancer. Materials and methods: Thirty patients with carcinoma of the oral cavity or hypopharynx underwent PET/CT and contrast-enhanced neck MRI for initial staging before surgery including primary tumor resection and neck dissection. Diagnostic performance of PET/CT, MRI, and retrospective image fusion of PET and MRI (fused PET/MRI) for assessment of the extent of the primary tumor (T stage) and metastasis to regional lymph nodes (N stage) was evaluated. Results: Accuracy for T status was 87% for fused PET/MRI and 90% for MRI, thus proving significantly superior to PET/CT, which had an accuracy of 67% (p = 0.041 and p = 0.023, respectively). Accuracy for N status was 77% for both fused PET/MRI and PET/CT, being superior to MRI, which had an accuracy of 63%, although the difference was not significant (p = 0.13). On a per-level basis, the sensitivity, specificity and accuracy for detection of nodal metastasis were 77%, 96% and 93% for both fused PET/MRI and PET/CT, compared with 49%, 99% and 91% for MRI, respectively. The differences for sensitivity (p = 0.0026) and accuracy (p = 0.041) were significant. Conclusion: Fused PET/MRI combining the individual advantages of MRI and PET is a valuable technique for assessment of staging neck cancer.

  17. Temporomandibular joint (TMJ) pain revisited with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

    Science.gov (United States)

    Tasali, N; Cubuk, R; Aricak, M; Ozarar, M; Saydam, B; Nur, H; Tuncbilek, N

    2012-03-01

    We aimed to assess the contrast enhancement patterns of the retrodiscal tissue with dynamic contrast-enhanced MR imaging (DCE-MRI) with respect to different temporomandibular joint disc pathologies. Additionally, we questioned the relationship between the temporomandibular joint (TMJ) pain and the contrast enhancement pattern of the retrodiscal tissue regardless of the TMJ disc position. 52 joints of 26 patients (4 males and 22 females) who have pain in at least at one of their TMJ were included in this study. For the qualitative analysis, the joints were divided into four groups in terms of their disc positions: normal (1), partially displaced with or without reduction (2), totally dislocated with reduction (3) and totally dislocated without reduction (4). Besides, two different joint groups were constituted, namely the painful group and painless group according to the clinical findings without taking the TMJ disc positions into account. Quantitative analyses were made by means of measuring signal intensity ratios (SI) ratio at the retrodiscal tissue (from internal side and external side of the each joint) using DCE-MRI and these measurements were analyzed with paired samples t test to define the difference between the measurements. At the second stage, the time-dependent arithmetical mean values of the SI ratios were calculated for each joint group and significant differences between the groups were questioned using analysis of variance (ANOVA) test. Besides, painful and painless groups which were classified on the basis of the clinical data were compared according to the mean SI ratios found for each joint and the significant differences between these two groups were assessed by means of Student's T test. The results were assessed in 95% confidence interval where the significance level was pjoints with partial displacement. Another significant difference was found between the average time versus SI ratio curves of the four groups. In consequence of the

  18. Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones

    OpenAIRE

    Olschewski, Andrea; Wolff, Matthias; Bräu, Michael E; Hempelmann, Gunter; Vogel, Werner; Safronov, Boris V.

    2002-01-01

    Combining the patch-clamp recordings in slice preparation with the ‘entire soma isolation' method we studied action of several local anaesthetics on delayed-rectifier K+ currents in spinal dorsal horn neurones.Bupivacaine, lidocaine and mepivacaine at low concentrations (1–100 μM) enhanced delayed-rectifier K+ current in intact neurones within the spinal cord slice, while exhibiting a partial blocking effect at higher concentrations (>100 μM). In isolated somata 0.1–10 μM bupivacaine enhanced...

  19. Enhanced insulin sensitivity in prepubertal children with constitutional delay of growth and development.

    Science.gov (United States)

    Wilson, Dyanne A; Hofman, Paul L; Miles, Harriet L; Sato, Tim A; Billett, Nathalie E; Robinson, Elizabeth M; Cutfield, Wayne S

    2010-02-01

    To test the hypothesis that prepubertal children with presumed constitutional delay of growth and development (CDGD) have enhanced insulin sensitivity and, therefore, insulin sensitivity is associated with later onset of puberty. Twenty-one prepubertal children with presumed CDGD and 23 prepubertal control children, underwent a frequently sampled intravenous glucose tolerance test to evaluate insulin sensitivity and other markers of insulin, glucose, and growth regulation. Children in the CDGD group were shorter and leaner than control subjects. Children with presumed CDGD were 40% more insulin sensitive (17.0 x 10(-4) min(-1)/[mU/L] versus 12.1 x 10(-4) min(-1)/[mU/L]; P = .0006) and had reduced acute insulin response, thus maintaining euglycemia (216 mU/L versus 330 mU/L; P = .02) compared with control subjects. In addition, the CDGD group had lower serum insulin-like growth factor binding protein 3 levels (3333 ng/mL versus 3775 ng/mL; P = .0004) and a trend toward lower serum insulin-like growth factor-II levels (794 ng/mL versus 911 ng/mL; P = .06). Prepubertal children with presumed CDGD have enhanced insulin sensitivity, supporting the hypothesis that insulin sensitivity is associated with timing of puberty. It may signify long-term biological advantages with lower risk of metabolic syndrome and malignancy. Copyright 2010 Mosby, Inc. All rights reserved.

  20. Characterization of Benign Myocarditis Using Quantitative Delayed-Enhancement Imaging Based on Molli T1 Mapping.

    Science.gov (United States)

    Toussaint, Marcel; Gilles, Raymond J; Azzabou, Noura; Marty, Benjamin; Vignaud, Alexandre; Greiser, Andreas; Carlier, Pierre G

    2015-10-01

    Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.

  1. Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

    Energy Technology Data Exchange (ETDEWEB)

    Chiriac, L.B.; Trandafir, D.L. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Turcu, R.V.F. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Todea, M. [Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania)

    2016-11-01

    Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy{sub 2}O{sub 3}. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, {sup 29}Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T{sub 1} and RARE-T{sub 2} protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T{sub 2}-weighted MRI contrast properties.

  2. Corticospinal Tract Tracing in the Marmoset with a Clinical Whole-Body 3T Scanner Using Manganese-Enhanced MRI.

    Science.gov (United States)

    Demain, Boris; Davoust, Carole; Plas, Benjamin; Bolan, Faye; Boulanouar, Kader; Renaud, Luc; Darmana, Robert; Vaysse, Laurence; Vieu, Christophe; Loubinoux, Isabelle

    2015-01-01

    Manganese-enhanced MRI (MEMRI) has been described as a powerful tool to depict the architecture of neuronal circuits. In this study we investigated the potential use of in vivo MRI detection of manganese for tracing neuronal projections from the primary motor cortex (M1) in healthy marmosets (Callithrix Jacchus). We determined the optimal dose of manganese chloride (MnCl2) among 800, 400, 40 and 8 nmol that led to manganese-induced hyperintensity furthest from the injection site, as specific to the corticospinal tract as possible, and that would not induce motor deficit. A commonly available 3T human clinical MRI scanner and human knee coil were used to follow hyperintensity in the corticospinal tract 24h after injection. A statistical parametric map of seven marmosets injected with the chosen dose, 8 nmol, showed the corticospinal tract and M1 connectivity with the basal ganglia, substantia nigra and thalamus. Safety was determined for the lowest dose that did not induce dexterity and grip strength deficit, and no behavioral effects could be seen in marmosets who received multiple injections of manganese one month apart. In conclusion, our study shows for the first time in marmosets, a reliable and reproducible way to perform longitudinal ME-MRI experiments to observe the integrity of the marmoset corticospinal tract on a clinical 3T MRI scanner.

  3. Electrical stimulation does not enhance nerve regeneration if delayed after sciatic nerve injury: the role of fibrosis

    Directory of Open Access Journals (Sweden)

    Na Han

    2015-01-01

    Full Text Available Electrical stimulation has been shown to accelerate and enhance nerve regeneration in sensory and motor neurons after injury, but there is little evidence that focuses on the varying degrees of fibrosis in the delayed repair of peripheral nerve tissue. In this study, a rat model of sciatic nerve transection injury was repaired with a biodegradable conduit at 1 day, 1 week, 1 month and 2 months after injury, when the rats were divided into two subgroups. In the experimental group, rats were treated with electrical stimuli of frequency of 20 Hz, pulse width 100 ms and direct current voltage of 3 V; while rats in the control group received no electrical stimulation after the conduit operation. Histological results showed that stained collagen fibers comprised less than 20% of the total operated area in the two groups after delayed repair at both 1 day and 1 week but after longer delays, the collagen fiber area increased with the time after injury. Immunohistochemical staining revealed that the expression level of transforming growth factor β (an indicator of tissue fibrosis decreased at both 1 day and 1 week after delayed repair but increased at both 1 and 2 months after delayed repair. These findings indicate that if the biodegradable conduit repair combined with electrical stimulation is delayed, it results in a poor outcome following sciatic nerve injury. One month after injury, tissue degeneration and distal fibrosis are apparent and are probably the main reason why electrical stimulation fails to promote nerve regeneration after delayed repair.

  4. MRI enhancement of the facial nerve with Gd-DTPA, 2; Investigation of enhanced nerve portions in patients with facial palsy

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Masahiro (Kansai Medical School, Moriguchi, Osaka (Japan))

    1993-08-01

    We performed enhanced MRI using Gd-DTPA in 84 patients with facial palsy. After assessing enhancement of the normal facial nerve, we examined enhancement in patients with Bell's palsy and Ramsay Hunt syndrome. In 95% of patients with Bell's palsy, enhancement was obtained in the distal IAC and labyrinthine portions. In 72%, enhancement was significant from the distal IAC portion through the vertical portion. In some of the patients who underwent enhanced MRI twice, increased signal intensity was observed in distal portions such as the vertical portion. In many cases of Ramsay Hunt syndrome, enhancement was seen extensively in the IAC portion through the vertical portion. In the subjects with internal auditory symptoms such as vertigo and tinnitus, enhancement of the IAC portion was seen not only in the facial nerve but also in the vestibular and the cochlear nerves. These results suggest that the vascular permeability of lesions in Bell's palsy may be increased from the distal IAC portion to the vertical portion. Judging from the present findings with Ramsay Hunt syndrome, symptoms related to the enhanced portions suggest that accompanying internal auditory symptoms occur due to inflammation of the IAC portions of cochlear and vestibular nerves. (author).

  5. The correlation of contrast-enhanced ultrasound and MRI perfusion quantitative analysis in rabbit VX2 liver cancer.

    Science.gov (United States)

    Xiang, Zhiming; Liang, Qianwen; Liang, Changhong; Zhong, Guimian

    2014-12-01

    Our objective is to explore the value of liver cancer contrast-enhanced ultrasound (CEUS) and MRI perfusion quantitative analysis in liver cancer and the correlation between these two analysis methods. Rabbit VX2 liver cancer model was established in this study. CEUS was applied. Sono Vue was applied in rabbits by ear vein to dynamically observe and record the blood perfusion and changes in the process of VX2 liver cancer and surrounding tissue. MRI perfusion quantitative analysis was used to analyze the mean enhancement time and change law of maximal slope increasing, which were further compared with the pathological examination results. Quantitative indicators of liver cancer CEUS and MRI perfusion quantitative analysis were compared, and the correlation between them was analyzed by correlation analysis. Rabbit VX2 liver cancer model was successfully established. CEUS showed that time-intensity curve of rabbit VX2 liver cancer showed "fast in, fast out" model while MRI perfusion quantitative analysis showed that quantitative parameter MTE of tumor tissue increased and MSI decreased: the difference was statistically significant (P 0.05). However, the quantitative parameter of them were significantly positively correlated (P liver cancer lesion and surrounding liver parenchyma, and the quantitative parameters of them are correlated. The combined application of both is of importance in early diagnosis of liver cancer.

  6. Magic angle-enhanced MRI of fibrous microstructures in sclera and cornea with and without intraocular pressure loading.

    Science.gov (United States)

    Ho, Leon C; Sigal, Ian A; Jan, Ning-Jiun; Squires, Alexander; Tse, Zion; Wu, Ed X; Kim, Seong-Gi; Schuman, Joel S; Chan, Kevin C

    2014-08-07

    The structure and biomechanics of the sclera and cornea are central to several eye diseases such as glaucoma and myopia. However, their roles remain unclear, partly because of limited noninvasive techniques to assess their fibrous microstructures globally, longitudinally, and quantitatively. We hypothesized that magic angle-enhanced magnetic resonance imaging (MRI) can reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure (IOP) elevation. Seven ovine eyes were extracted and fixed at IOP = 50 mm Hg to mimic ocular hypertension, and another 11 eyes were unpressurized. The sclera and cornea were scanned at different angular orientations relative to the main magnetic field inside a 9.4-Tesla MRI scanner. Relative MRI signal intensities and intrinsic transverse relaxation times (T2 and T2*) were determined to quantify the magic angle effect on the corneoscleral shells. Three loaded and eight unloaded tendon samples were scanned as controls. At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and light/dark bands indicative of collagen fiber crimps in the sclera and tendon. Magic angle enhancement effect was the strongest in tendon and the least strong in cornea. Loaded sclera, cornea, and tendon possessed significantly higher T2 and T2* than unloaded tissues at magic angle. Magic angle-enhanced MRI can detect ocular fibrous microstructures without contrast agents or coatings and can reveal their MR tissue property changes with IOP loading. This technique may open up new avenues for assessment of the biomechanical and biochemical properties of ocular tissues in aging and in diseases involving the corneoscleral shell. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  7. Magic Angle–Enhanced MRI of Fibrous Microstructures in Sclera and Cornea With and Without Intraocular Pressure Loading

    Science.gov (United States)

    Ho, Leon C.; Sigal, Ian A.; Jan, Ning-Jiun; Squires, Alexander; Tse, Zion; Wu, Ed X.; Kim, Seong-Gi; Schuman, Joel S.; Chan, Kevin C.

    2014-01-01

    Purpose. The structure and biomechanics of the sclera and cornea are central to several eye diseases such as glaucoma and myopia. However, their roles remain unclear, partly because of limited noninvasive techniques to assess their fibrous microstructures globally, longitudinally, and quantitatively. We hypothesized that magic angle–enhanced magnetic resonance imaging (MRI) can reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure (IOP) elevation. Methods. Seven ovine eyes were extracted and fixed at IOP = 50 mm Hg to mimic ocular hypertension, and another 11 eyes were unpressurized. The sclera and cornea were scanned at different angular orientations relative to the main magnetic field inside a 9.4-Tesla MRI scanner. Relative MRI signal intensities and intrinsic transverse relaxation times (T2 and T2*) were determined to quantify the magic angle effect on the corneoscleral shells. Three loaded and eight unloaded tendon samples were scanned as controls. Results. At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and light/dark bands indicative of collagen fiber crimps in the sclera and tendon. Magic angle enhancement effect was the strongest in tendon and the least strong in cornea. Loaded sclera, cornea, and tendon possessed significantly higher T2 and T2* than unloaded tissues at magic angle. Conclusions. Magic angle–enhanced MRI can detect ocular fibrous microstructures without contrast agents or coatings and can reveal their MR tissue property changes with IOP loading. This technique may open up new avenues for assessment of the biomechanical and biochemical properties of ocular tissues in aging and in diseases involving the corneoscleral shell. PMID:25103267

  8. Identifying Triple-Negative Breast Cancer Using Background Parenchymal Enhancement Heterogeneity on Dynamic Contrast-Enhanced MRI: A Pilot Radiomics Study.

    Directory of Open Access Journals (Sweden)

    Jeff Wang

    Full Text Available To determine the added discriminative value of detailed quantitative characterization of background parenchymal enhancement in addition to the tumor itself on dynamic contrast-enhanced (DCE MRI at 3.0 Tesla in identifying "triple-negative" breast cancers.In this Institutional Review Board-approved retrospective study, DCE-MRI of 84 women presenting 88 invasive carcinomas were evaluated by a radiologist and analyzed using quantitative computer-aided techniques. Each tumor and its surrounding parenchyma were segmented semi-automatically in 3-D. A total of 85 imaging features were extracted from the two regions, including morphologic, densitometric, and statistical texture measures of enhancement. A small subset of optimal features was selected using an efficient sequential forward floating search algorithm. To distinguish triple-negative cancers from other subtypes, we built predictive models based on support vector machines. Their classification performance was assessed with the area under receiver operating characteristic curve (AUC using cross-validation.Imaging features based on the tumor region achieved an AUC of 0.782 in differentiating triple-negative cancers from others, in line with the current state of the art. When background parenchymal enhancement features were included, the AUC increased significantly to 0.878 (p<0.01. Similar improvements were seen in nearly all subtype classification tasks undertaken. Notably, amongst the most discriminating features for predicting triple-negative cancers were textures of background parenchymal enhancement.Considering the tumor as well as its surrounding parenchyma on DCE-MRI for radiomic image phenotyping provides useful information for identifying triple-negative breast cancers. Heterogeneity of background parenchymal enhancement, characterized by quantitative texture features on DCE-MRI, adds value to such differentiation models as they are strongly associated with the triple-negative subtype

  9. Simulation-based comparison of two approaches frequently used for dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Zwick, Stefan [Siemens AG, Healthcare Sector, Erlangen (Germany); German Cancer Research Center (DKFZ), Department of Medical Physics in Radiology, Heidelberg (Germany); University Hospital Freiburg, Department of Diagnostic Radiology, Medical Physics, Freiburg (Germany); Brix, Gunnar [Federal Office for Radiation Protection, Department of Medical and Occupational Radiation Protection, Munich (Germany); Tofts, Paul S. [Brighton and Sussex Medical School, Imaging Physics, Falmer, Sussex (United Kingdom); Strecker, Ralph [Siemens AG, Healthcare Sector, Erlangen (Germany); Kopp-Schneider, Annette [German Cancer Research Center (DKFZ), Biostatistics, Heidelberg (Germany); Laue, Hendrik [Fraunhofer MEVIS, Bremen (Germany); Semmler, Wolfhard [German Cancer Research Center (DKFZ), Department of Medical Physics in Radiology, Heidelberg (Germany); Kiessling, Fabian [RWTH-Aachen University, Experimental Molecular Imaging, Medical Faculty, Aachen (Germany)

    2010-02-15

    The purpose was to compare two approaches for the acquisition and analysis of dynamic-contrast-enhanced MRI data with respect to differences in the modelling of the arterial input-function (AIF), the dependency of the model parameters on physiological parameters and their numerical stability. Eight hundred tissue concentration curves were simulated for different combinations of perfusion, permeability, interstitial volume and plasma volume based on two measured AIFs and analysed according to the two commonly used approaches. The transfer constants (Approach 1) K {sup trans} and (Approach 2) k{sub ep} were correlated with all tissue parameters. K {sup trans} showed a stronger dependency on perfusion, and k{sub ep} on permeability. The volume parameters (Approach 1) v{sub e} and (Approach 2) A were mainly influenced by the interstitial and plasma volume. Both approaches allow only rough characterisation of tissue microcirculation and microvasculature. Approach 2 seems to be somewhat more robust than 1, mainly due to the different methods of CA administration. (orig.)

  10. Adaptive k-space sampling design for edge-enhanced DCE-MRI using compressed sensing.

    Science.gov (United States)

    Raja, Rajikha; Sinha, Neelam

    2014-09-01

    The critical challenge in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is the trade-off between spatial and temporal resolution due to the limited availability of acquisition time. To address this, it is imperative to under-sample k-space and to develop specific reconstruction techniques. Our proposed method reconstructs high-quality images from under-sampled dynamic k-space data by proposing two main improvements; i) design of an adaptive k-space sampling lattice and ii) edge-enhanced reconstruction technique. A high-resolution data set obtained before the start of the dynamic phase is utilized. The sampling pattern is designed to adapt to the nature of k-space energy distribution obtained from the static high-resolution data. For image reconstruction, the well-known compressed sensing-based total variation (TV) minimization constrained reconstruction scheme is utilized by incorporating the gradient information obtained from the static high-resolution data. The proposed method is tested on seven real dynamic time series consisting of 2 breast data sets and 5 abdomen data sets spanning 1196 images in all. For data availability of only 10%, performance improvement is seen across various quality metrics. Average improvements in Universal Image Quality Index and Structural Similarity Index Metric of up to 28% and 24% on breast data and about 17% and 9% on abdomen data, respectively, are obtained for the proposed method as against the baseline TV reconstruction with variable density random sampling pattern. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Assessment of therapeutic response in brain tuberculomas using serial dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Haris, M. [Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India); Gupta, R.K. [Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India)], E-mail: rgupta@sgpgi.ac.in; Husain, M.; Srivastava, C. [Departments of Neurosurgery, King George' s Medical University, Lucknow (India); Singh, A.; Singh Rathore, R.K. [Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur (India); Saksena, S. [Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India); Behari, S. [Department of Neurosurgery, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India); Husain, N. [Department of Pathology, King George' s Medical University, Lucknow (India); Mohan Pandey, C. [Department of Biostatistics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India); Nath Prasad, K. [Department of Microbiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India)

    2008-05-15

    Aim: To assess the most useful dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) index in the evaluation of the therapeutic response in brain tuberculoma (BT) patients. Subjects and methods: Twenty-three patients with 25 BT lesions were serially evaluated using DCE MRI. All lesions were classified into two groups: group I (n = 15) included patients who showed clinical, as well as imaging, improvement; and group II (n = 10) included patients with either clinical or radiological deterioration. The group I and group II lesions were examined for up to 12 months at 4 monthly intervals. However, the lesions in five patients of group II were excised following clinical deterioration after 4 months of therapy. The perfusion indices, i.e., relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), permeability (k{sup trans}), and leakage (v{sub e}), were quantified at each time point. The cellular, necrotic, and total volumes of lesion, together with the oedema volume, were also calculated. Results: All patients in group I and three in group II showed a significant decrease in all perfusion indices, together with the oedema volume, after 1 year. In these three patients in group II, increase in rCBV was associated with increased cellular volume fraction whereas the k{sup trans}, v{sub e}, and oedema volume decreased significantly after 4 months. In five patients in group II who underwent excision of the lesion after 4 months of therapy due to clinical deterioration, the decrease in rCBV was associated with significant increase in k{sup trans} and oedema volume without any significant change in lesion volume. The rCBV correlated significantly with the cellular volume, whereas k{sup trans} showed a significant correlation with the v{sub e} and oedema volume at each time point. Conclusion: In BT, changes in k{sup trans} and oedema volume are associated with a therapeutic response at 4 months, even when there is a paradoxical increase in the lesion

  12. Comparison of contrast enhanced MR-angiography-MRI and digital subtraction angiography in the evaluation of pancreas and/or kidney transplantation patients : initial experience

    NARCIS (Netherlands)

    Boeve, WJ; Kok, T; Tegzess, Adam; van Son, WJ; Ploeg, RJ; Sluiter, WJ; Kamman, RL

    2001-01-01

    To evaluate whether combined contrast enhanced MRA and MRI (ce-MRA-MRI) has the potential to replace intra-arterial DSA (i.a.DSA) in patients with impaired graft function or suspected of vascular complications after pancreas and/or kidney transplantation. 7 patients after combined pancreas-kidney an

  13. Delayed Intraparenchymal and Intraventricular Hemorrhage Requiring Surgical Evacuation after MRI-Guided Laser Interstitial Thermal Therapy for Lesional Epilepsy.

    Science.gov (United States)

    Barber, Sean M; Tomycz, Luke; George, Timothy; Clarke, Dave F; Lee, Mark

    2017-01-01

    Symptomatic intracranial hemorrhage is a rare complication of laser interstitial thermal therapy (LITT). To present a unique case of delayed symptomatic intracranial hemorrhage occurring after a LITT procedure for epilepsy in a high-volume center (68 LITT procedures for pediatric epilepsy have been performed). An 18-year-old male with epilepsy underwent LITT to an area of heterotopia near the right lateral ventricle. He did well initially and was discharged home on postoperative day 1 but returned on postoperative day 9 with headache and left hemiparesis. He was found to have intraparenchymal and intraventricular hemorrhage in the region of the LITT catheter tract. CT angiography on admission revealed a small vascular abnormality near the focus of hemorrhage suspicious for pseudoaneurysm, although conventional angiography was negative. The patient declined neurologically and underwent craniotomy and hemorrhage evacuation. He eventually convalesced and was discharged to inpatient rehabilitation with persistent left hemiparesis. He has been seizure free since the intervention but remains on antiepileptic drugs. Evidence from the literature suggests that the pathophysiology of symptomatic hemorrhage after LITT may be related to vascular injury and pseudoaneurysm formation from LITT catheter placement and/or thermal injury from the ablation itself. © 2017 S. Karger AG, Basel.

  14. Correlation of histological findings with gadolinium enhanced MRI scans during healing of a PHEMA orbital implant in rabbits

    OpenAIRE

    Hicks, C.; Morris, I.; Vijayasekaran, S; Fallon, M.; McAllister, J.; Clayton, A.; Chirila, T.; Crawford, G; Constable, I

    1999-01-01

    BACKGROUND/AIMS—To investigate a poly(2-hydroxyethyl methacrylate) (PHEMA) orbital implant with a spongy anterior hemisphere and a smooth gel posterior hemisphere, by histology correlated with magnetic resonance images.
METHODS—Following enucleation, eight rabbits received PHEMA implants to which the muscles were directly sutured, and underwent gadolinium enhanced magnetic resonance imaging (MRI) from 3 to 52 weeks. After the rabbits were killed, the implants were removed, cut in a plane corr...

  15. Vehicle Position Estimation Based on Magnetic Markers: Enhanced Accuracy by Compensation of Time Delays

    Directory of Open Access Journals (Sweden)

    Yeun-Sub Byun

    2015-11-01

    Full Text Available The real-time recognition of absolute (or relative position and orientation on a network of roads is a core technology for fully automated or driving-assisted vehicles. This paper presents an empirical investigation of the design, implementation, and evaluation of a self-positioning system based on a magnetic marker reference sensing method for an autonomous vehicle. Specifically, the estimation accuracy of the magnetic sensing ruler (MSR in the up-to-date estimation of the actual position was successfully enhanced by compensating for time delays in signal processing when detecting the vertical magnetic field (VMF in an array of signals. In this study, the signal processing scheme was developed to minimize the effects of the distortion of measured signals when estimating the relative positional information based on magnetic signals obtained using the MSR. In other words, the center point in a 2D magnetic field contour plot corresponding to the actual position of magnetic markers was estimated by tracking the errors between pre-defined reference models and measured magnetic signals. The algorithm proposed in this study was validated by experimental measurements using a test vehicle on a pilot network of roads. From the results, the positioning error was found to be less than 0.04 m on average in an operational test.

  16. Detailed analysis of contrast-enhanced MRI of hands and wrists in patients with psoriatic arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Tehranzadeh, Jamshid [University of California, Department of Radiological Sciences, Irvine (United States); University of California Medical Center, Department of Radiological Sciences R-140, Orange, CA (United States); Ashikyan, Oganes; Anavim, Arash; Shin, John [University of California, Department of Radiological Sciences, Irvine (United States)

    2008-05-15

    The objective was to perform detailed analysis of the involved soft tissues, tendons, joints, and bones in the hands and wrists of patients with psoriatic arthritis (PsA). We reviewed 23 contrast-enhanced MR imaging studies (13 hands and 10 wrists) in 10 patients with the clinical diagnosis of PsA. We obtained clinical information from medical records and evaluated images for the presence of erosions, bone marrow edema, joint synovitis, tenosynovitis, carpal tunnel, and soft tissue involvement. Two board-certified musculoskeletal radiologists reviewed all images independently. Differences were resolved during a subsequent joint session. The average duration of disease was 71.3 months, ranging from 1 month to 25 years. Eight of the 10 wrists (80%) and 6 of the 13 hands demonstrated bone erosions. Bone marrow abnormalities were shown in 5 of the 10 wrists (50%) and 4 of the 14 hands (31%). Triangular fibrocartilage tears were seen in 6 of the 10 wrists (60%). Wrist and hand joint synovitis were present in all studies (67 wrist joints and 101 hand joints). Wrist soft tissue involvement was detected in 9 of the 10 wrists (90%) and hand soft tissue involvement was present in 12 of the 13 wrists (92%). Findings adjacent to the region of soft tissue involvement included synovitis (4 wrists) and tenosynovitis (3 wrists). Bone marrow edema adjacent to the region of soft tissue involvement was seen in one wrist. Bulge of the flexor retinaculum was seen in 4 of the 10 wrists (40%) and median nerve enhancement was seen in 8 of the 10 wrists (80%). Tenosynovitis was seen in all studies (all 10 of the hands and all 13 of the wrists). The 'rheumatoid' type of distribution of bony lesions was common in our study. Interobserver agreement for various findings ranged from 83% to 100%. Contrast-enhanced MRI unequivocally demonstrated bone marrow edema, erosions, tendon and soft-tissue disease, and median nerve involvement, with good interobserver reliability in patients with

  17. Correlation of histological findings from a large ciliochoroidal melanoma with CT perfusion and 3T MRI dynamic enhancement studies

    Directory of Open Access Journals (Sweden)

    Jose S Pulido

    2008-06-01

    Full Text Available Jose S Pulido1, Norbert G Campeau2, Ernst Klotz3, Andrew N Primak2, Osama Saba3, Kaan Gunduz1, Herbert Cantrill5, Diva Salomão1,4, Cynthia H McCollough21Department of Ophthalmology; 2Department of Radiology; 3Siemens Medical Solutions, Malvern, PA, USA; 4Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA; 5VitreoRetinal Surgery, Minneapolis, MN, USABackground: The initial use of a 64-slice computed tomography (CT scanner for obtaining quantitative perfusion data from a large ciliochoroidal melanoma, and correlation with 3T magnetic resonance imaging (MRI dynamic enhancement and tumor histology.Methods: The CT perfusion scan was performed using 80 kVp, 250 mA and 1-sec rotation time for 40 sec. The analysis was performed using commercial perfusion analysis software with a prototype 3-dimensional motion correction tool. Dynamic contrast-enhanced 3-Tesla MRI measured the kinetics of enhancement to estimate the vascular permeability. The time-dependent enhancement patterns were obtained using the average signal intensity using Functool analysis software. The involved globe was enucleated and microscopic evaluation of the tumor was performed.Results: The perfusion parameters blood flow, blood volume and permeability surface area product in the affected eye determined by CT perfusion analysis were 118 ml/100 ml/min, 11.3 ml/100 ml and 48 ml/100 ml/min. Dynamic MRI enhancement showed maximal intensity increase of 111%. The neoplasm was a ciliochoroidal spindle cell melanoma which was mitotically active (13 mitoses/40 hpf. Vascular loops and arcades were present throughout the tumor. The patient developed metastases within 9 months of presentation.Conclusion: Quantitative CT perfusion analysis of ocular tumors is feasible with motion correction software.Keywords: ciliochoroidal melanoma, CT perfusion imaging, MR enhancement imaging, tumor blood volume, tumor blood flow, tumor permeability

  18. Prediction of prostate cancer extracapsular extension with high spatial resolution dynamic contrast-enhanced 3-T MRI

    Energy Technology Data Exchange (ETDEWEB)

    Bloch, B.N. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Radiology, Boston, MA (United States); Boston Medical Center and Boston University, Department of Radiology, Boston, MA (United States); Genega, Elizabeth M. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Pathology, Boston, MA (United States); Costa, Daniel N.; Pedrosa, Ivan; Rofsky, Neil M. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Radiology, Boston, MA (United States); University of Texas Southwestern Medical Center, Department of Radiology, Dallas, TX (United States); Smith, Martin P.; Kressel, Herbert Y. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Radiology, Boston, MA (United States); Ngo, Long [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of General Medicine, Boston, MA (United States); Sanda, Martin G.; DeWolf, William C. [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Division of Urology, Boston, MA (United States)

    2012-10-15

    To assess the value of dynamic contrast-enhanced (DCE) combined with T2-weighted (T2W) endorectal coil (ERC) magnetic resonance imaging (MRI) at 3 T for determining extracapsular extension (ECE) of prostate cancer. In this IRB-approved study, ERC 3-T MRI of the prostate was performed in 108 patients before radical prostatectomy. T2W fast spin-echo and DCE 3D gradient echo images were acquired. The interpretations of readers with varied experience were analysed. MRI-based staging results were compared with radical prostatectomy histology. Descriptive statistics were generated for prediction of ECE and staging accuracies were determined by the area under the receiver-operating characteristic curve. The overall sensitivity, specificity, positive predictive value and negative predictive value for ECE were 75 %, 92 %, 79 % and 91 %, respectively. Diagnostic accuracy for staging was 86 %, 80 % and 91 % for all readers, experienced and less experienced readers, respectively. ERC 3-T MRI of the prostate combining DCE and T2W imaging is an accurate pretherapeutic staging tool for assessment of ECE in clinical practice across varying levels of reader experience. (orig.)

  19. Characterization of tumor vasculature in mouse brain by USPIO contrast-enhanced MRI.

    NARCIS (Netherlands)

    Gambarota, G.; Leenders, W.P.J.

    2011-01-01

    Detailed characterization of the tumor vasculature provides a better understanding of the complex mechanisms associated with tumor development and is especially important to evaluate responses to current therapies which target the tumor vasculature. Magnetic resonance imaging (MRI) studies of tumors

  20. The incremental value of contrast-enhanced MRI in the detection of biopsy-proven local recurrence of prostate cancer after radical prostatectomy: effect of reader experience.

    Science.gov (United States)

    Wassberg, Cecilia; Akin, Oguz; Vargas, Hebert Alberto; Shukla-Dave, Amita; Zhang, Jingbo; Hricak, Hedvig

    2012-08-01

    The purpose of this study is to retrospectively assess the incremental value of contrast-enhanced MRI (CE-MRI) to T2-weighted MRI in the detection of postsurgical local recurrence of prostate cancer by readers of different experience levels, using biopsy as the reference standard. Fifty-two men with biochemical recurrence after prostatectomy underwent 1.5-T endorectal MRI with multiphase contrast-enhanced imaging and had biopsy within 3 months of MRI. Two radiologists (reader 1 had 1 year and reader 2 had 6 years of experience) independently reviewed each MRI study and classified the likelihood of recurrent cancer on a 5-point scale. Areas under receiver operating characteristic curves (A(z)) were calculated to assess readers' diagnostic performance with T2-weighted MRI alone and combined with CE-MRI. Interobserver agreement was assessed using Cohen kappa statistics. Thirty-three patients (63%) had biopsy-proven local recurrence of prostate cancer. With the addition of CE-MRI to T2-weighted imaging, the A(z) for cancer detection increased significantly for reader 1 (0.77 vs 0.85; p = 0.0435) but not for reader 2 (0.86 vs 0.88; p = 0.7294). The use of CE-MRI improved interobserver agreement from fair (κ = 0.39) to moderate (κ = 0.58). CE-MRI increased interobserver agreement and offered incremental value to T2-weighted MRI in the detection of locally recurrent prostate cancer for the relatively inexperienced reader.

  1. Predicting local recurrence following breast-conserving treatment: parenchymal signal enhancement ratio (SER) around the tumor on preoperative MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Young; Cho, Nariya; Koo, Hye Ryoung; Yun, Bo La; Bae, Min Sun; Moon, Woo Kyung [Dept. of Radiology, Seoul National Univ. Coll. of Medicine, Seoul National Univ. Hospital, Seoul (Korea, Republic of)], e-mail: river7774@gmail.com; Chie, Eui Kyu [Dept. of Radiation Oncology, Seoul National Univ. Coll. of Medicine, Seoul National Univ. Hospital, Seoul (Korea, Republic of)

    2013-09-15

    Background: The level of background parenchymal enhancement around tumor is known to be associated with breast cancer risk. However, there is no study investigating predictive power of parenchymal signal enhancement ratio (SER) around tumor for ipsilateral breast tumor recurrence (IBTR). Purpose: To investigate whether the breast parenchymal SER around the tumor on preoperative dynamic contrast-enhanced magnetic resonance imaging (MRI) is associated with subsequent IBTR in breast cancer patients who had undergone breast-conserving treatment. Material and Methods: Nineteen consecutive women (mean age, 44 years; range, 34-63 years) with breast cancer who developed IBTR following breast-conserving treatment and 114 control women matched for age, as well as T and N stages were included. We compared the clinicopathologic features of the two groups including nuclear grade, histologic grade, hormonal receptor status, human epidermal growth factor receptor-2 (HER-2) status, lymphovascular invasion, negative margin width, use of adjuvant therapy, and parenchymal SER around the tumor on preoperative DCE-MRI. The SER was measured on a slice showing the largest dimension of the tumor. Multivariate conditional logistic regression analysis was used to identify independent factors associated with IBTR. Results: In univariate analysis, ER negativity (odds ratio [OR] = 4.7; P = 0.040), PR negativity (OR = 4.0; P = 0.013), HER-2 positivity (OR = 3.6; P = 0.026), and a parenchymal SER greater than 0.53 (OR = 23.3; P = 0.011) were associated with IBTR. In multivariate analysis, ER negativity (OR = 3.8; P = 0.015) and a parenchymal SER greater than 0.53 (OR = 13.2; P = 0.040) on preoperative MRI were independent factors associated with IBTR. Conclusion: In addition to ER negativity, a higher parenchymal SER on preoperative MRI was an independent factor associated with subsequent IBTR in patients with breast cancer who had undergone breast-conserving treatment.

  2. Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip.

    Science.gov (United States)

    Palmer, A; Fernquest, S; Rombach, I; Park, D; Pollard, T; Broomfield, J; Bangerter, N; Carr, A; Glyn-Jones, S

    2017-09-01

    Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = -0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  3. Diagnostic efficacy of gadoxetic acid (Primovist)-enhanced MRI and spiral CT for a therapeutic strategy: comparison with intraoperative and histopathologic findings in focal liver lesions

    Energy Technology Data Exchange (ETDEWEB)

    Hammerstingl, Renate; Vogl, Thomas J. [Johann Wolfgang Goethe-Univ., Inst. of Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Huppertz, Alexander [Imaging Science Inst., Charite - Siemens, Berlin (Germany); Breuer, Josy; Balzer, Thomas [Gobal Clinical Development Diagnostics, Bayer Schering Pharma AG, Berlin (Germany); Blakeborough, Anthony [Royal Hallamshire Hospital, Dept. of Radiology, Sheffield (United Kingdom); Carter, Rick [Bayer Health Care Ltd., Burgess Hill, West Sussex (United Kingdom); Castells Fuste, Lluis [Hospital Vall d' Hebron, Liver Unit, Dept. of Internal Medicine, Barcelona (Spain); Heinz-Peer, Gertraud [Universitaetsklinik fuer Radiodiagnostik, Allg. Krankenhaus der Stadt Wien, Wien (Germany); Judmaier, Werner [Univ. Hospital Innsbruck, Dept. of Magnetic Resonance Imaging and Spectroscopy, Innsbruck (Austria); Laniado, Michael [Universitaetsklinikum Carl Gustav Carus, Technische Univ. Dresden, Inst. for Diagnostic Radiology, Dresden (Germany); Manfredi, Riccardo M. [Univ. of Verona, Dept. of Radiology, Verona (Italy); Mathieu, Didier G. [Centre d' Imagerie, Aix en Provence (France); Mueller, Dieter [Georg-August Univ., Dept. of Radiology, Goettingen (Germany); Mortele, Koenraad [Brigham and Women' s Hospital, Dept. of Radiology (L1), Boston, MA (United States); Reimer, Peter [Klinikum Karlsruhe, Dept. of Radiology, Karlsruhe (Germany); Reiser, Maximilian F. [Ludwig-Maximilians-Univ. Munich - Klinikum Grosshadern, Inst. of Clinical Radiology, Munich (Germany); Robinson, Philip J. [St James' s Univ. Hospital, Dept. of Clinical Radiology, Leeds (United Kingdom); Shamsi, Kohkan [Berlex Labs. Inc., Montville, NJ (United States); Strotzer, Michael [Univ. Hospital, Dept. of Diagnostic Radiology, Regensburg (Germany); Taupitz, Matthias [Universitaetsklinikum Charite, Med. Fakultaet der Humboldt-Univ., Dept. of Radiology, Berlin (Germany); Tombach, Bernd; Valeri, Gianluca; Beers, Bernhard E. van [and others

    2008-03-15

    A multicenter study has been employed to evaluate the diagnostic efficacy of magnetic resonance imaging (MRI) using the new liver-specific contrast agent gadoxetic acid (Gd-EOB-DTPA, Primovist), as opposed to contrast-enhanced biphasic spiral computed tomography (CT), in the diagnosis of focal liver lesions, compared with a standard of reference (SOR). One hundred and sixty-nine patients with hepatic lesions eligible for surgery underwent Gd-EOB-DTPA-enhanced MRI as well as CT within 6 weeks. Pathologic evaluation of the liver specimen combined with intraoperative ultrasound established the SOR. Data sets were evaluated on-site (14 investigators) and off-site (three independent blinded readers). Gd-EOB-DTPA was well tolerated. Three hundred and two lesions were detected in 131 patients valid for analysis by SOR. The frequency of correctly detected lesions was significantly higher on Gd-EOB-DTPA-enhanced MRI compared with CT in the clinical evaluation [10.44%; 95% confidence interval (CI): 4.88, 16.0]. In the blinded reading there was a trend towards Gd-EOB-DTPA-enhanced MRI, not reaching statistical significance (2.14%; 95% CI: -4.32, 8.6). However, the highest rate of correctly detected lesions with a diameter below 1 cm was achieved by Gd-EOB-DTPA-enhanced MRI. Differential diagnosis was superior for Gd-EOB-DTPA-enhanced MRI (82.1%) versus CT (71.0%). A change in surgical therapy was documented in 19 of 131 patients (14.5%) post Gd-EOB-DTPA-enhanced MRI. Gd-EOB-DTPA-enhanced MRI was superior in the diagnosis and therapeutic management of focal liver lesions compared with CT. (orig.)

  4. Optimization of saturation-recovery dynamic contrast-enhanced MRI acquisition protocol: monte carlo simulation approach demonstrated with gadolinium MR renography.

    Science.gov (United States)

    Zhang, Jeff L; Conlin, Chris C; Carlston, Kristi; Xie, Luke; Kim, Daniel; Morrell, Glen; Morton, Kathryn; Lee, Vivian S

    2016-07-01

    Dynamic contrast-enhanced (DCE) MRI is widely used for the measurement of tissue perfusion and to assess organ function. MR renography, which is acquired using a DCE sequence, can measure renal perfusion, filtration and concentrating ability. Optimization of the DCE acquisition protocol is important for the minimization of the error propagation from the acquired signals to the estimated parameters, thus improving the precision of the parameters. Critical to the optimization of contrast-enhanced T1 -weighted protocols is the balance of the T1 -shortening effect across the range of gadolinium (Gd) contrast concentration in the tissue of interest. In this study, we demonstrate a Monte Carlo simulation approach for the optimization of DCE MRI, in which a saturation-recovery T1 -weighted gradient echo sequence is simulated and the impact of injected dose (D) and time delay (TD, for saturation recovery) is tested. The results show that high D and/or high TD cause saturation of the peak arterial signals and lead to an overestimation of renal plasma flow (RPF) and glomerular filtration rate (GFR). However, the use of low TD (e.g. 100 ms) and low D leads to similar errors in RPF and GFR, because of the Rician bias in the pre-contrast arterial signals. Our patient study including 22 human subjects compared TD values of 100 and 300 ms after the injection of 4 mL of Gd contrast for MR renography. At TD = 100 ms, we computed an RPF value of 157.2 ± 51.7 mL/min and a GFR of 33.3 ± 11.6 mL/min. These results were all significantly higher than the parameter estimates at TD = 300 ms: RPF = 143.4 ± 48.8 mL/min (p = 0.0006) and GFR = 30.2 ± 11.5 mL/min (p = 0.0015). In conclusion, appropriate optimization of the DCE MRI protocol using simulation can effectively improve the precision and, potentially, the accuracy of the measured parameters. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Enhanced secure strategy for electro-optic chaotic systems with delayed dynamics by using fractional Fourier transformation.

    Science.gov (United States)

    Cheng, Mengfan; Deng, Lei; Li, Hao; Liu, Deming

    2014-03-10

    We propose a scheme whereby a time domain fractional Fourier transform (FRFT) is used to post process the optical chaotic carrier generated by an electro-optic oscillator. The time delay signature of the delay dynamics is successfully masked by the FRFT when some conditions are satisfied. Meanwhile the dimension space of the physical parameters is increased. Pseudo random binary sequence (PRBS) with low bit rate (hundreds of Mbps) is introduced to control the parameters of the FRFT. The chaotic optical carrier, FRFT parameters and the PRBS are covered by each other so that the eavesdropper has to search the whole key space to crack the system. The scheme allows enhancing the security of communication systems based on delay dynamics without modifying the chaotic source. In this way, the design of chaos based communication systems can be implemented in a modular manner.

  6. Early detection of temporomandibular joint arthritis in children with juvenile idiopathic arthritis - the role of contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, Thekla von; Stuber, Tina; Winkler, Peter [Olgahospital Klinikum Stuttgart, Pediatric Radiology, Radiologisches Institut, Stuttgart (Germany); Maier, Jan; Hospach, Toni [Olgahospital Klinikum Stuttgart, Pediatric Rheumatology, Stuttgart (Germany)

    2015-03-01

    Early treatment of temporomandibular joint (TMJ) arthritis is crucial in children with juvenile idiopathic arthritis (JIA) to prevent permanent functional impairment. As involvement of TMJs is often asymptomatic, contrast-enhanced MRI is regarded as the most sensitive noninvasive diagnostic tool. To evaluate the degree of contrast enhancement in TMJs of children and adolescents with JIA in comparison to normal controls from a previous study. Dynamic contrast-enhanced MRI of 50 children and adolescents with JIA (6.3 to 18 years of age; mean: 12 years) were retrospectively analysed. We assessed morphological abnormalities and postcontrast time-intensity curves of the soft joint tissue and the mandibular condyle. Ratios were calculated to quantify postcontrast signal intensities (SI) in relation to precontrast SI at initial (1 min postcontrast) and maximum (6 min postcontrast) increase. Time-intensity curves followed similar biphasic patterns in normal and pathological joints. In joints with morphological signs of arthritis, mean SI ratios were on average higher than in normal joints of the reference group, but ranges of values widely overlapped. Arthritis: mean initial increase of SI 62% (±2 S.D. 18-105%), mean maximum SI 106% higher than precontrast (±2 S.D. 46-166%). Normal: mean initial increase of SI 49% (±2 S.D. 14- 85%), mean maximum of SI 73% (±2 S.D. 23-123%). Given this considerable overlap of results in dynamic contrast-enhanced MRI, the degree of contrast enhancement alone did not allow differentiation between TMJs with and without signs of inflammation. Thickening of the soft joint tissue seems to remain the earliest sign to reliably indicate TMJ arthritis. (orig.)

  7. A suspicious breast lesion detected by dynamic contrast-enhanced MRI and pathologically confirmed as capillary hemangioma: A case report and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lian He; Li, Qing Chang; Xu, Hong Tao; Wang, Xin; Wang, En Hua [The First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang (China); Ma, Shuang [Dept. of Neurology, Sheng Jing Hospital of China Medical University, Shenyang (China)

    2013-12-15

    Breast capillary hemangioma is a type of benign vascular tumor which is rarely seen. Little is known about its presentation on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we describe a case of suspicious breast lesion detected by DCE-MRI and pathologically confirmed as capillary hemangioma. Our case indicates that a small mass with a superficial location, clear boundary, and homogeneous enhancement on DCE-MRI indicates the possible diagnosis of hemangioma, whereby even the lesion presents a washout type curve.

  8. Accuracy of non-enhanced MRI to monitor histological lesion size during laser-induced interstitial thermotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Bremer, Christoph; Kreft, Gerald [Department of Clinical Radiology, University of Muenster (Germany); Filler, Timm [Institute for Anatomy, University of Muenster (Germany); Reimer, Peter [Zentralinstitut fuer Bildgebende Diagnostik, Staedtisches Klinikum Karlsruhe (Germany)

    2002-01-01

    The purpose of this study was to assess the accuracy of non-enhanced MRI using a T1-weighted 2D turbo fast low-angle shot (FLASH) sequence during laser-induced interstitial thermotherapy (LITT) to determine histological lesion size of laser-induced hepatic lesions. The LITT was performed on pig liver samples at various power settings and durations. For MR monitoring during and after LITT a T1-weighted 2D turbo-FLASH sequence was applied. Lesions seen by MRI during and after LITT were correlated with histological lesion size. Histologically, a core zone of complete tissue ablation close to the tip of the applicator could be differentiated from an adjacent transitional zone showing incomplete necrosis. Magnetic resonance imaging right at the end of LITT (i.e., with maximum heating effects) grossly overestimated the core zone but accurately described the transitional zone. Magnetic resonance imaging after cooling of the tissue (therefore showing structural as opposed to thermal changes) exactly depicted the core zone of complete tissue ablation. Non-enhanced MRI using a T1-weighted 2D turbo FLASH sequence strongly overestimates the histological lesion size during LITT; however, structural changes of the tissue seen after cooling accurately define lesion size in LITT. For clinical purposes the lesion geometry seen during MR monitoring should therefore well extend the tumor margins. (orig.)

  9. Envelope enhancement increases cortical sensitivity to interaural envelope delays with acoustic and electric hearing.

    Directory of Open Access Journals (Sweden)

    Douglas E H Hartley

    Full Text Available Evidence from human psychophysical and animal electrophysiological studies suggests that sensitivity to interaural time delay (ITD in the modulating envelope of a high-frequency carrier can be enhanced using half-wave rectified stimuli. Recent evidence has shown potential benefits of equivalent electrical stimuli to deaf individuals with bilateral cochlear implants (CIs. In the current study we assessed the effects of envelope shape on ITD sensitivity in the primary auditory cortex of normal-hearing ferrets, and profoundly-deaf animals with bilateral CIs. In normal-hearing animals, cortical sensitivity to ITDs (±1 ms in 0.1-ms steps was assessed in response to dichotically-presented i sinusoidal amplitude-modulated (SAM and ii half-wave rectified (HWR tones (100-ms duration; 70 dB SPL presented at the best-frequency of the unit over a range of modulation frequencies. In separate experiments, adult ferrets were deafened with neomycin administration and bilaterally-implanted with intra-cochlear electrode arrays. Electrically-evoked auditory brainstem responses (EABRs were recorded in response to bipolar electrical stimulation of the apical pair of electrodes with singe biphasic current pulses (40 µs per phase over a range of current levels to measure hearing thresholds. Subsequently, we recorded cortical sensitivity to ITDs (±800 µs in 80-µs steps within the envelope of SAM and HWR biphasic-pulse trains (40 µs per phase; 6000 pulses per second, 100-ms duration over a range of modulation frequencies. In normal-hearing animals, nearly a third of cortical neurons were sensitive to envelope-ITDs in response to SAM tones. In deaf animals with bilateral CI, the proportion of ITD-sensitive cortical neurons was approximately a fifth in response to SAM pulse trains. In normal-hearing and deaf animals with bilateral CI the proportion of ITD sensitive units and neural sensitivity to ITDs increased in response to HWR, compared with SAM stimuli

  10. Accurate determination of blood–brain barrier permeability using dynamic contrast-enhanced T1-weighted MRI

    DEFF Research Database (Denmark)

    Cramer, Stig P; Larsson, Henrik B W

    2014-01-01

    of total measurement duration, temporal resolution, and modeling approach under varying physiologic circumstances. To estimate accuracy and precision of the DCE-MRI method we generated simulated data using a two-compartment model and progressively down-sampled and truncated the data to mimic low temporal......Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is increasingly used to estimate permeability in situations with subtle blood-brain barrier (BBB) leakage. However, the method's ability to differentiate such low values from zero is unknown, and no consensus exists on optimal selection...... resolution and short total measurement duration. Model fit was performed with the Patlak, the extended Tofts, and the Tikhonov two-compartment (Tik-2CM) models. Overall, 17 healthy controls were scanned to obtain in vivo data. Long total measurement duration (15 minutes) and high temporal resolution (1...

  11. Triggered non-contrast enhanced MR angiography of peripheral arteries: Optimization of systolic and diastolic time delays for electrocardiographic triggering

    Energy Technology Data Exchange (ETDEWEB)

    Radlbauer, Rudolf, E-mail: rudolf.radlbauer@stpoelten.lknoe.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Salomonowitz, Erich, E-mail: erich.salomonowitz@stpoelten.lknoe.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Riet, Wilma van der, E-mail: wilma@emric.fr [European MRI Consultancy (EMRIC), 4 rue Gutenberg, 67000 Strasbourg (France); Stadlbauer, Andreas, E-mail: andi@nmr.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany)

    2011-11-15

    The purpose of this study was to determine the optimal systolic and diastolic time delays for electrocardiographic triggering of a non-contrast media enhanced MR angiography using a 3-dimensional fast spin echo sequence in patients suffering from peripheral arterial disease. 12 patients with suspected peripheral arterial disease were examined on a 1.5 T Philips Achieva MR scanner. A cardiac-triggered Volumetric Isotropic T2-weighted fast spin echo sequence was performed using variable trigger delays for systolic and diastolic phase. The signal in the popliteal arteries and anterior tibial arteries of the systolic and diastolic images was measured and optimal delay times for systolic and diastolic phase were determined. Minimum signal to noise ratio (SNR) appears at the time difference {Delta}T = -21 ms on systolic images of the popliteal arteries. In the anterior tibial arteries the minimum SNR is significantly higher and appears at the time difference {Delta}T = -14 ms. Diastolic delay times must be chosen as long or as short as possible depending on heart rate. In peripheral vessels triggered non-contrast MR angiography can yield results which are comparable with contrast enhanced MRA techniques. It is crucial to optimize timing parameters.

  12. Non-rigid alignment of pre-operative MRI, fMRI, and DT-MRI with intra-operative MRI for enhanced visualization and navigation in image-guided neurosurgery.

    Science.gov (United States)

    Archip, Neculai; Clatz, Olivier; Whalen, Stephen; Kacher, Dan; Fedorov, Andriy; Kot, Andriy; Chrisochoides, Nikos; Jolesz, Ferenc; Golby, Alexandra; Black, Peter M; Warfield, Simon K

    2007-04-01

    The usefulness of neurosurgical navigation with current visualizations is seriously compromised by brain shift, which inevitably occurs during the course of the operation, significantly degrading the precise alignment between the pre-operative MR data and the intra-operative shape of the brain. Our objectives were (i) to evaluate the feasibility of non-rigid registration that compensates for the brain deformations within the time constraints imposed by neurosurgery, and (ii) to create augmented reality visualizations of critical structural and functional brain regions during neurosurgery using pre-operatively acquired fMRI and DT-MRI. Eleven consecutive patients with supratentorial gliomas were included in our study. All underwent surgery at our intra-operative MR imaging-guided therapy facility and have tumors in eloquent brain areas (e.g. precentral gyrus and cortico-spinal tract). Functional MRI and DT-MRI, together with MPRAGE and T2w structural MRI were acquired at 3 T prior to surgery. SPGR and T2w images were acquired with a 0.5 T magnet during each procedure. Quantitative assessment of the alignment accuracy was carried out and compared with current state-of-the-art systems based only on rigid registration. Alignment between pre-operative and intra-operative datasets was successfully carried out during surgery for all patients. Overall, the mean residual displacement remaining after non-rigid registration was 1.82 mm. There is a statistically significant improvement in alignment accuracy utilizing our non-rigid registration in comparison to the currently used technology (paugmented reality visualization to aid the surgeon.

  13. Non-rigid alignment of preoperative MRI, fMRI, and DT-MRI with intra-operative MRI for enhanced visualization and navigation in image-guided neurosurgery

    Science.gov (United States)

    Archip, Neculai; Clatz, Olivier; Whalen, Stephen; Kacher, Dan; Fedorov, Andriy; Kot, Andriy; Chrisochoides, Nikos; Jolesz, Ferenc; Golby, Alexandra; Black, Peter M.; Warfield, Simon K.

    2012-01-01

    Objective The usefulness of neurosurgical navigation with current visualizations is seriously compromised by brain shift, which inevitably occurs during the course of the operation, significantly degrading the precise alignment between the preoperative MR data and the intra-operative shape of the brain. Our objectives were (i) to evaluate the feasibility of non-rigid registration that compensates for the brain deformations within the time constraints imposed by neurosurgery, and (ii) create augmented reality visualizations of critical structural and functional brain regions during neurosurgery using pre-operatively acquired fMRI and DT-MRI. Materials and Methods Eleven consecutive patients with supratentorial gliomas were included in our study. All underwent surgery at our intra-operative MR imaging–guided therapy facility and have tumors in eloquent brain areas (e.g. precentral gyrus and cortico-spinal tract). Functional MRI and DT-MRI, together with MPRAGE and T2w structural MRI were acquired at 3T prior to surgery. SPGR and T2w images were acquired with a 0.5T magnet during each procedure. Quantitative assessment of the alignment accuracy was carried out and compared with current state-of the-art systems based only on rigid-registration. Results Alignment between preoperative and intra-operative datasets was successfully carried out during surgery for all patients. Overall, the mean residual displacement remaining after non-rigid registration was 1.82 mm. There is a statistically significant improvement in alignment accuracy utilizing our non-rigid registration in comparison to the currently used technology (paugmented reality visualization to aid the surgeon. PMID:17289403

  14. Angiogenesis in hematological malignancy – Evaluated by dynamic contrast-enhanced MRI

    Directory of Open Access Journals (Sweden)

    Tiffany Ting-Fang Shih

    2016-12-01

    Full Text Available Bone marrow angiogenesis can be measured by DCE-MRI. DCE-MRI is an imaging technique that appears to provide quantitative and biologically relevant information related to tumor vasculature and angiogenesis, which can inform novel drug efficacy, monitor treatment response and act as an imaging biomarker to predict treatment outcome and survival in hematological malignant patients. Increased bone marrow perfusion as reflected by higher Peak value can independently predict adverse clinical outcome in patients with acute myeloid leukemia (AML. In addition, DCE-MRI derived data of bone marrow in AML patients at remission status provides useful information on clinical outcome of patients who might have relapse or not. Patients with a higher value for Kep at remission status would have shorter relapse-free duration and may need to undergo additional therapy. In multiple myeloma, DCE-MRI data correlate strongly with marrow tissue microvessel density. Studies identify high Amplitude values as a possible risk factor associated with the development of extra-medullary disease in multiple myeloma patients; these findings partly support the hypothesis that bone marrow angiogenesis may play role in the development of extra-medullary disease in multiple myeloma. DCE-MRI derived-parameters could serve as a guidance for the selection of optimal management plans, thereby contributing to the development of “personalized medicine” for patient.

  15. Detection of local recurrent prostate cancer after radical prostatectomy in terms of salvage radiotherapy using dynamic contrast enhanced-MRI without endorectal coil

    Directory of Open Access Journals (Sweden)

    Rischke Hans Christian

    2012-10-01

    Full Text Available Abstract Purpose To evaluate the value of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI without endorectal coil (EC in the detection of local recurrent prostate cancer (PC after radical prostatectomy (RP. Material and methods Thirty-three patients with recurrent PC underwent DCE-MRI without EC before salvage radiotherapy (RT. At median 15 (mean 16±4.9, range 12–27 months after completion of RT all patients showed complete biochemical response. Additional follow up post RT DCE-MRI scans were available. Prostate specific antigen (PSA levels at the time of imaging were correlated to the imaging findings. Results In 22/33 patients (67% early contrast enhancing nodules were detected in the post-prostatectomy fossa on pre-RT DCE-MRI images. The average pre-RT PSA level of the 22 patients with positive pre-RT DCE-MRI findings was significantly higher (mean, 0.74±0.64 ng/mL compared to the pre-RT PSA level of the 11 patients with negative pre-RT DCE-MRI (mean, 0.24±0.13 ng/mL (p Conclusions This is the first study that shows that DCE-MRI without EC can detect local recurrent PC with an estimated accuracy of 83% at low PSA levels. All false negative DCE-MRI scans were detected using a PSA cut-off of ≥0.54 ng/mL.

  16. Chronological observation in early radiation myelopathy of the cervical spinal cord; Gadolinium-enhanced MRI findings in two cases

    Energy Technology Data Exchange (ETDEWEB)

    Hirota, Saeko; Yoshida, Shoji; Soejima, Toshinori (Hyogo Medical Center for Adults, Akashi (Japan)) (and others)

    Gd-enhanced MR images of two patients with clinically and histopathologically diagnosed chronic progressive radiation myelitis (CPRM) were observed chronologically. One of them had had nasopharyngeal cancer and received radiotherapy at a dose of 100 Gy to the C1-2 level of the spinal cord. She developed CPRM 25 months after the termination of radiotherapy. The other had had malignant lymphoma originating from the tonsil and received chemoradiotherapy. The dose delivered to her cervical spinal cord was 40 Gy, and she developed CPRM 30 months later. Gd-enhanced MRI in the early phase revealed a small crescent-shaped nidus with or without a very small central nonenhanced area in both cases. Enhancement was not great. At that time, patients noticed only the inability to perceive pain and temperature or paresthesia in the opposite side. In a few months, MRI revealed a much more strongly enhanced and larger nidus with enlargement of a central nonenhanced area accompanied by long segmental cord enlargement. The patients' neurological symptoms had also progressed, with hemiparesis developing, for example. (author).

  17. The Role of Dynamic Contrast-Enhanced MRI in a Child with Sport-Induced Avascular Necrosis of the Scaphoid: A Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Baris Beytullah Koc

    2016-01-01

    Full Text Available Avascular necrosis (AVN of the scaphoid in children is very rare and there is currently no consensus when conservative or operative treatment is indicated. A 10-year-old boy, practicing karate, presented with acute pain in his left wrist after falling on the outstretched hand. Imaging showed a scaphoid waist fracture with signs of an ongoing AVN. The diagnosis of AVN was confirmed with signal loss of the scaphoid on MRI T1. A dynamic contrast-enhanced MRI was performed for further assessment of the proximal pole vascularity and treatment planning. As dynamic contrast-enhanced MRI showed fair perfusion of the proximal pole, an adequate healing potential with conservative treatment was estimated. We achieved union and good function with cast immobilization for fourteen weeks. This case study showed dynamic contrast-enhanced MRI to be a valuable tool in assessing whether conservative or operative treatment is indicated to achieve union and good functional outcome.

  18. Diagnostic value of delayed washout rate of contrast-enhanced multi ...

    African Journals Online (AJOL)

    Rania Essameldein Mohamed

    2013-12-18

    Dec 18, 2013 ... assessment of the diagnostic value of 15-min delayed washout rate in the differentiation of these incidentally .... pine and scans were obtained during breath hold. Images ..... On the other hand, CT contrast washout rate tests.

  19. Transient Severe Motion Artifact Related to Gadoxetate Disodium-Enhanced Liver MRI: Frequency and Risk Evaluation at a German Institution.

    Science.gov (United States)

    Well, Lennart; Rausch, Vanessa Hanna; Adam, Gerhard; Henes, Frank Oliver; Bannas, Peter

    2017-07-01

    Purpose Varying frequencies (5 - 18 %) of contrast-related transient severe motion (TSM) imaging artifacts during gadoxetate disodium-enhanced arterial phase liver MRI have been reported. Since previous reports originated from the United States and Japan, we aimed to determine the frequency of TSM at a German institution and to correlate it with potential risk factors and previously published results. Materials and Methods Two age- and sex-matched groups were retrospectively selected (gadoxetate disodium n = 89; gadobenate dimeglumine n = 89) from dynamic contrast-enhanced MRI examinations in a single center. Respiratory motion-related artifacts in non-enhanced and dynamic phases were assessed independently by two readers blinded to contrast agents on a 4-point scale. Scores of ≥ 3 were considered as severe motion artifacts. Severe motion artifacts in arterial phases were considered as TSM if scores in all other phases were  0.05). Conclusion We revealed a high frequency of TSM after injection of gadoxetate disodium at a German institution, substantiating the importance of a diagnosis-limiting phenomenon that so far has only been reported from the United States and Japan. In accordance with previous studies, we did not identify associated risk factors for TSM. Key Points:  · Gadoxetate disodium causes TSM in a relevant number of patients.. · The frequency of TSM is similar between the USA, Japan and Germany.. · To date, no validated risk factors for TSM could be identified.. Citation Format · Well L, Rausch VH, Adam G et al. Transient Severe Motion Artifact Related to Gadoxetate Disodium-Enhanced Liver MRI: Frequency and Risk Evaluation at a German Institution. Fortschr Röntgenstr 2017; 189: 651 - 660. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Reproducibility of dynamic contrast-enhanced MRI and dynamic susceptibility contrast MRI in the study of brain gliomas: a comparison of data obtained using different commercial software.

    Science.gov (United States)

    Conte, Gian Marco; Castellano, Antonella; Altabella, Luisa; Iadanza, Antonella; Cadioli, Marcello; Falini, Andrea; Anzalone, Nicoletta

    2017-04-01

    Dynamic susceptibility contrast MRI (DSC) and dynamic contrast-enhanced MRI (DCE) are useful tools in the diagnosis and follow-up of brain gliomas; nevertheless, both techniques leave the open issue of data reproducibility. We evaluated the reproducibility of data obtained using two different commercial software for perfusion maps calculation and analysis, as one of the potential sources of variability can be the software itself. DSC and DCE analyses from 20 patients with gliomas were tested for both the intrasoftware (as intraobserver and interobserver reproducibility) and the intersoftware reproducibility, as well as the impact of different postprocessing choices [vascular input function (VIF) selection and deconvolution algorithms] on the quantification of perfusion biomarkers plasma volume (Vp), volume transfer constant (K (trans)) and rCBV. Data reproducibility was evaluated with the intraclass correlation coefficient (ICC) and Bland-Altman analysis. For all the biomarkers, the intra- and interobserver reproducibility resulted in almost perfect agreement in each software, whereas for the intersoftware reproducibility the value ranged from 0.311 to 0.577, suggesting fair to moderate agreement; Bland-Altman analysis showed high dispersion of data, thus confirming these findings. Comparisons of different VIF estimation methods for DCE biomarkers resulted in ICC of 0.636 for K (trans) and 0.662 for Vp; comparison of two deconvolution algorithms in DSC resulted in an ICC of 0.999. The use of single software ensures very good intraobserver and interobservers reproducibility. Caution should be taken when comparing data obtained using different software or different postprocessing within the same software, as reproducibility is not guaranteed anymore.

  1. Predicting response before initiation of neoadjuvant chemotherapy in breast cancer using new methods for the analysis of dynamic contrast enhanced MRI (DCE MRI) data

    Science.gov (United States)

    DeGrandchamp, Joseph B.; Whisenant, Jennifer G.; Arlinghaus, Lori R.; Abramson, V. G.; Yankeelov, Thomas E.; Cárdenas-Rodríguez, Julio

    2016-03-01

    The pharmacokinetic parameters derived from dynamic contrast enhanced (DCE) MRI have shown promise as biomarkers for tumor response to therapy. However, standard methods of analyzing DCE MRI data (Tofts model) require high temporal resolution, high signal-to-noise ratio (SNR), and the Arterial Input Function (AIF). Such models produce reliable biomarkers of response only when a therapy has a large effect on the parameters. We recently reported a method that solves the limitations, the Linear Reference Region Model (LRRM). Similar to other reference region models, the LRRM needs no AIF. Additionally, the LRRM is more accurate and precise than standard methods at low SNR and slow temporal resolution, suggesting LRRM-derived biomarkers could be better predictors. Here, the LRRM, Non-linear Reference Region Model (NRRM), Linear Tofts model (LTM), and Non-linear Tofts Model (NLTM) were used to estimate the RKtrans between muscle and tumor (or the Ktrans for Tofts) and the tumor kep,TOI for 39 breast cancer patients who received neoadjuvant chemotherapy (NAC). These parameters and the receptor statuses of each patient were used to construct cross-validated predictive models to classify patients as complete pathological responders (pCR) or non-complete pathological responders (non-pCR) to NAC. Model performance was evaluated using area under the ROC curve (AUC). The AUC for receptor status alone was 0.62, while the best performance using predictors from the LRRM, NRRM, LTM, and NLTM were AUCs of 0.79, 0.55, 0.60, and 0.59 respectively. This suggests that the LRRM can be used to predict response to NAC in breast cancer.

  2. Volumetry of [{sup 11}C]-methionine PET uptake and MRI contrast enhancement in patients with recurrent glioblastoma multiforme

    Energy Technology Data Exchange (ETDEWEB)

    Galldiks, Norbert; Schroeter, Michael; Fink, Gereon R. [University Hospital of Cologne, Department of Neurology, Cologne (Germany); Ullrich, Roland; Kracht, Lutz W. [Max Planck-Institute for Neurological Research, Cologne (Germany)

    2010-01-15

    We investigated the relationship between three-dimensional volumetric data of the metabolically active tumour volume assessed using [{sup 11}C]-methionine positron emission tomography (MET-PET) and the area of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) enhancement assessed using magnetic resonance imaging (MRI) in patients with recurrent glioblastoma (GBM). MET-PET and contrast-enhanced MRI with Gd-DTPA were performed in 12 uniformly pretreated patients with recurrent GBM. To calculate the volumes in cubic centimetres, a threshold-based volume-of-interest (VOI) analysis of the metabolically active tumour volume (MET uptake indexes of {>=}1.3 and {>=}1.5) and of the area of Gd-DTPA enhancement was performed after coregistration of all images. In all patients, the metabolically active tumour volume as shown using a MET uptake index of {>=}1.3 was larger than the volume of Gd-DTPA enhancement (30.2 {+-} 22.4 vs. 13.7 {+-} 10.6 cm{sup 3}; p = 0.04). Metabolically active tumour volumes as shown using MET uptake indexes of {>=}1.3 and {>=}1.5 and the volumes of Gd-DTPA enhancement showed a positive correlation (r = 0.76, p = 0.003, for an index of {>=}1.3, and r = 0.74, p = 0.005, for an index of {>=}1.5). The present data suggest that in patients with recurrent GBM the metabolically active tumour volume may be substantially underestimated by Gd-DTPA enhancement. The findings support the notion that complementary information derived from MET uptake and Gd-DTPA enhancement may be helpful in developing individualized, patient-tailored therapy strategies in patients with recurrent GBM. (orig.)

  3. Enhancement of abdominal structures on MRI at 1.5 and 3 T: a retrospective intraindividual crossover comparison

    Energy Technology Data Exchange (ETDEWEB)

    AlObaidy, Mamdoh [King Faisal Specialist Hospital and Research Center, Department of Radiology, Riyadh (Saudi Arabia); University of North Carolina at Chapel Hill, Department of Radiology, Chapel Hill, NC (United States); Ramalho, Miguel; Velloni, Fernanda; Matos, Antonio P.; Herman, Kevin; Semelka, Richard C. [University of North Carolina at Chapel Hill, Department of Radiology, Chapel Hill, NC (United States)

    2017-04-15

    To quantitatively compare the extent of enhancement of abdominal structures on MRI in an intraindividual fashion at 1.5 and 3 T. HIPAA-compliant, retrospective, longitudinal, intraindividual, crossover study, with waived informed consent, of consecutive individuals scanned at both 1.5 and 3 T closed-bore magnets using gadobenate dimeglumine during different phases of enhancement at tightly controlled arterial phase timing. Quantitative ROI measurements and qualitative sub-phase arterial phase assignments were independently performed by two radiologists. Qualitative discrepancies were resolved by a senior radiologist. Final population included 60 patients [41 female and 19 male; age, 49.35 ± 18.31 years (range 16-81); weight, 78.88 ± 20.3 kg (range 44.5-136)]. Similar enhancement peak patterns were noted at both field strengths. Interobserver agreement of quantitative evaluations was substantial. Significantly higher amplitudes of enhancement peaks were noted for all abdominal solid organs during all phases at 3 T, except for the pancreas (p = 0.17-0.30). Significantly higher amplitudes of enhancement peaks of the abdominal aorta at 1.5 T were noted. Similar peak patterns of enhancement for abdominal structures were observed at 1.5 and 3 T, with solid abdominal organs showing a higher percentage enhancement at 3 T, while unexpectedly higher aortic higher percentage enhancement was observed at 1.5 T. (orig.)

  4. Enhanced sensitivity of a mountain bog to climate change as a delayed effect of road construction

    Directory of Open Access Journals (Sweden)

    P. von Sengbusch

    2015-01-01

    Full Text Available Trees of Pinus rotundata (bog pine characterise many bogs in the mid-altitude mountains of central Europe (Switzerland, East and South Germany, Czech Republic. The research described here focuses on recent changes in the growth of bog pine on the Ennersbacher Moor, a mountain mire in the Black Forest (south-west Germany. An increase in the cover of bog pine is usually caused by drainage and subsequent drawdown of the water table. However, this bog has not been drained or directly disturbed in any other way. One possible explanation is that a road constructed in 1983 along one margin of the bog has diverted part of its water supply. Even though the road was designed to conduct potentially salt-contaminated drainage water away from the bog, its construction did not cause an immediate vegetation response in the 1980s and 1990s. Therefore, I hypothesise that it enhanced the sensitivity of the bog to climatic stress, predisposing it to a succession that was eventually triggered by a series of drought years in 2009–2011. Data collected near the centre of the bog over the period 1998–2014 indicate not only a distinct change in the relationship between height and trunk circumference of the trees, but also an increase of dwarf shrub cover and changes in the composition of Sphagnum communities. Although the pH of near-surface water may have increased slightly over this period, pH and EC values remain within typical ranges for raised bogs in the Black Forest. Examination of peat profiles reveals that the peat is more highly humified now than it was in 2002, and water table records from 2012–2014 show a greater amplitude of fluctuation than water table data collected in 1998–2001. Even though its mean level is only 105 mm below the ground surface, the water table is now observed to fall rapidly to depths of at least 350 mm during both wet and dry summers. Mapping surface (mesotopography and flow lines from the adjacent slope shows that the

  5. Enhanced antitumor efficacy of a vascular disrupting agent combined with an antiangiogenic in a rat liver tumor model evaluated by multiparametric MRI.

    Directory of Open Access Journals (Sweden)

    Feng Chen

    Full Text Available A key problem in solid tumor therapy is tumor regrowth from a residual viable rim after treatment with a vascular disrupting agent (VDA. As a potential solution, we studied a combined treatment of a VDA and antiangiogenic. This study was approved by the institutional ethical committee for the use and care of laboratory animals. Rats with implanted liver tumors were randomized into four treatment groups: 1 Zd6126 (Zd; 2 Thalidomide (Tha; 3 Zd in combination with Tha (ZdTha; and 4 controls. Multiparametric MRIs were performed and quantified before and after treatment. Circulating endothelial progenitor cells (EPCs and plasma stromal cell-derived factor-1α (SDF-1α were monitored. Tumor apoptosis, necrosis, and microvessels were verified by histopathology. A single use of Zd or Tha did not significantly delay tumor growth. The combined ZdTha showed enhanced antitumor efficacy due to synergistic effects; it induced a cumulative tumor apoptosis or necrosis, which resulted in significant delay in tumor growth and reduction in the viable tumor rim; it also reduced tumor vessel permeability; and it improved tumor hemodynamic indexes, most likely via a transient normalization of tumor vasculature induced by Tha. A stepwise linear regression analysis showed that the apparent diffusion coefficient was an independent predictor of tumor growth. We found no significant increases in Zd-induced circulating EPCs or plasma SDF-1α. ZdTha showed improved therapeutic efficacy in solid tumors compared to either agent alone. The therapeutic effects were successfully tracked in vivo with multiparametric MRI.

  6. Evaluation of T2-weighted and dynamic contrast-enhanced MRI in localizing prostate cancer before repeat biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Cheikh, Alexandre Ben; Girouin, Nicolas [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France)]|[Universite de Lyon, Lyon (France)]|[Universite de Lyon 1, faculte de medecine Lyon Nord, Lyon (France); Colombel, Marc; Marechal, Jean-Marie [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Gelet, Albert [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France)]|[Inserm, U556, Lyon (France); Bissery, Alvine; Rabilloud, Muriel [Hospices Civils de Lyon, Department of Biostatistics, Lyon (France)]|[Universite de Lyon 1, UMR CNRS 5558, Laboratoire Biostatistiques-Sante, Pierre-Benite (France); Lyonnet, Denis [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France)]|[Universite de Lyon, Lyon (France)]|[Universite de Lyon 1, faculte de medecine Lyon Nord, Lyon (France)]|[Inserm, U556, Lyon (France); Rouviere, Olivier [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France)]|[Universite de Lyon, Lyon (France)]|[Universite de Lyon 1, faculte de medecine Lyon Nord, Lyon (France)]|[Inserm, U556, Lyon (France)]|[Hopital Edouard Herriot, Department of Urinary and Vascular Radiology, Pavillon P Radio, Lyon Cedex 03 (France)

    2009-03-15

    We assessed the accuracy of T2-weighted (T2w) and dynamic contrast-enhanced (DCE) 1.5-T magnetic resonance imaging (MRI) in localizing prostate cancer before transrectal ultrasound-guided repeat biopsy. Ninety-three patients with abnormal PSA level and negative prostate biopsy underwent T2w and DCE prostate MRI using pelvic coil before repeat biopsy. T2w and DCE images were interpreted using visual criteria only. MR results were correlated with repeat biopsy findings in ten prostate sectors. Repeat biopsy found prostate cancer in 23 patients (24.7%) and 44 sectors (6.6%). At per patient analysis, the sensitivity, specificity, positive and negative predictive values were 47.8%, 44.3%, 20.4% and 79.5% for T2w imaging and 82.6%, 20%, 24.4% and 93.3% for DCE imaging. When all suspicious areas (on T2w or DCE imaging) were taken into account, a sensitivity of 82.6% and a negative predictive value of 100% could be achieved. At per sector analysis, DCE imaging was significantly less specific (83.5% vs. 89.7%, p < 0.002) than T2w imaging; it was more sensitive (52.4% vs. 32.1%), but the difference was hardly significant (p = 0.09). T2w and DCE MRI using pelvic coil and visual diagnostic criteria can guide prostate repeat biopsy, with a good sensitivity and NPV. (orig.)

  7. Placental Perfusion In Uterine Ischemia Model as Evaluated by Dynamic Contrast Enhanced MRI

    Science.gov (United States)

    Drobyshevsky, Alexander

    2017-01-01

    Background To validate DCE MRI method of placental perfusion estimation and to demonstrate application of the method in a rabbit model of fetal antenatal hypoxia-ischemia. Methods Placental perfusion was estimated by dynamic contrast imaging with bolus injection of Gd-DTPA in 3 Tesla GE magnet in a rabbit model of placental ischemia–reperfusion in rabbit dams at embryonic day 25 gestation age. Placental perfusion was measured using steepest slope method on DCE MRI before and after intermittent 40 min uterine ischemia. Antioxidants (n = 2 dams, 9 placentas imaged) or vehicle (n = 5 dams, 23 placenta imaged) were given systemically in a separate group of dams during reperfusion–reoxygenation. Placental perfusion was also measured in two dams from the antioxidant group (10 placentas) and two dams from the control group (12 placentas) by fluorescent microspheres method. Results While placental perfusion estimates between fluorescent microspheres and DCE MRI were significantly correlated (R2 = 0.85; P perfusion in reperfusion–reoxygenation phase in the saline, 0.44 ± 0.06 mL/min/g (P = 0.012, t-test), but not in the antioxidant group, 0.62 ± 0.06 mL/min/g, relative to preocclusion values (0.77 ± 0.07 and 0.84 ± 0.12 mL/min/g, correspondingly). Conclusion Underestimation of true perfusion in placenta by steepest slope DCE MRI is significant and the error appears to be systematic. PMID:25854322

  8. Pharmacokinetic analysis of Gd-DTPA enhancement in dynamic three-dimensional MRI of breast lesions

    NARCIS (Netherlands)

    denBoer, JA; Hoenderop, RKKM; Smink, J; Dornseiffen, G; Koch, PWAA; Mulder, JH; Slump, CH; Volker, EDP; deVos, RAI

    1997-01-01

    The purpose of this study was to demonstrate that dynamic MRI covering both breasts can provide sensitivity for tumor detection as well as specificity and sensitivity for differentiation of tumor malignancy, Three-dimensional gradient echo scans were used covering both breasts. Before Gd-DTPA bolus

  9. Enhancing 4D PC-MRI in an aortic phantom considering numerical simulations

    Science.gov (United States)

    Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Müller-Eschner, Matthias; Speidel, Stefanie; Farag, Mina; Beller, Carsten J.; Heuveline, Vincent

    2015-03-01

    To date, cardiovascular surgery enables the treatment of a wide range of aortic pathologies. One of the current challenges in this field is given by the detection of high-risk patients for adverse aortic events, who should be treated electively. Reliable diagnostic parameters, which indicate the urge of treatment, have to be determined. Functional imaging by means of 4D phase contrast-magnetic resonance imaging (PC-MRI) enables the time-resolved measurement of blood flow velocity in 3D. Applied to aortic phantoms, three dimensional blood flow properties and their relation to adverse dynamics can be investigated in vitro. Emerging "in silico" methods of numerical simulation can supplement these measurements in computing additional information on crucial parameters. We propose a framework that complements 4D PC-MRI imaging by means of numerical simulation based on the Finite Element Method (FEM). The framework is developed on the basis of a prototypic aortic phantom and validated by 4D PC-MRI measurements of the phantom. Based on physical principles of biomechanics, the derived simulation depicts aortic blood flow properties and characteristics. The framework might help identifying factors that induce aortic pathologies such as aortic dilatation or aortic dissection. Alarming thresholds of parameters such as wall shear stress distribution can be evaluated. The combined techniques of 4D PC-MRI and numerical simulation can be used as complementary tools for risk-stratification of aortic pathology.

  10. Preparation and initial characterization of biodegradable particles containing gadolinium-DTPA contrast agent for enhanced MRI

    Science.gov (United States)

    Doiron, Amber L.; Chu, Kevin; Ali, Adeel; Brannon-Peppas, Lisa

    2008-01-01

    Accurate imaging of atherosclerosis is a growing necessity for timely treatment of the disease. Magnetic resonance imaging (MRI) is a promising technique for plaque imaging. The goal of this study was to create polymeric particles of a small size with high loading of diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) and demonstrate their usefulness for MRI. A water-in-oil-in-oil double emulsion solvent evaporation technique was used to encapsulate the MRI agent in a poly(lactide-co-glycolide) (PLGA) or polylactide-poly(ethylene glycol) (PLA-PEG) particle for the purpose of concentrating the agent at an imaging site. PLGA particles with two separate average sizes of 1.83 μm and 920 nm, and PLA-PEG particles with a mean diameter of 952 nm were created. Loading of up to 30 wt % Gd-DTPA was achieved, and in vitro release occurred over 5 h. PLGA particles had highly negative zeta potentials, whereas the particles incorporating PEG had zeta potentials closer to neutral. Cytotoxicity of the particles on human umbilical vein endothelial cells (HUVEC) was shown to be minimal. The ability of the polymeric contrast agent formulation to create contrast was similar to that of Gd-DTPA alone. These results demonstrate the possible utility of the contrast agent-loaded polymeric particles for plaque detection with MRI. PMID:18796605

  11. Analysis of dynamic cerebral contrast-enhanced perfusion MRI time-series based on unsupervised clustering methods

    Science.gov (United States)

    Lange, Oliver; Meyer-Baese, Anke; Wismuller, Axel; Hurdal, Monica

    2005-03-01

    We employ unsupervised clustering techniques for the analysis of dynamic contrast-enhanced perfusion MRI time-series in patients with and without stroke. "Neural gas" network, fuzzy clustering based on deterministic annealing, self-organizing maps, and fuzzy c-means clustering enable self-organized data-driven segmentation w.r.t.fine-grained differences of signal amplitude and dynamics, thus identifying asymmetries and local abnormalities of brain perfusion. We conclude that clustering is a useful extension to conventional perfusion parameter maps.

  12. Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI--a comparison with contrast-enhanced MRI

    DEFF Research Database (Denmark)

    Eshed, Iris; Krabbe, Simon; Østergaard, Mikkel

    2015-01-01

    OBJECTIVES: To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. METHODS: Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2(nd)--5(th) metacarpophalangeal...... was very high per person (0.80--1.0), and moderate-high per joint (0.63--0.85), whereas exact agreements on scores were moderate (0.50--0.66). The intrareader agreement (15 patients and 3 controls) on presence/absence of synovitis was very high (0.87--1.0). CONCLUSIONS: Unenhanced MRI using STIR sequence...

  13. Enhancing motor network activity using real-time functional MRI neurofeedback of left premotor cortex

    Directory of Open Access Journals (Sweden)

    Theo Ferreira Marins

    2015-12-01

    Full Text Available Neurofeedback by functional Magnetic Resonance Imaging (fMRI is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC, important for motor recovery after brain injury. We investigated (i whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI task while receiving continuous fMRI-neurofeedback, and (ii whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and motor imagery, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke.

  14. Self-regulation strategies may enhance the acute effect of exercise on smoking delay.

    Science.gov (United States)

    Hatzigeorgiadis, Antonis; Pappa, Vassiliki; Tsiami, Anastasia; Tzatzaki, Theodora; Georgakouli, Kalliopi; Zourbanos, Nikos; Goudas, Marios; Chatzisarantis, Nikos; Theodorakis, Yannis

    2016-06-01

    The present study examined the acute effect of a moderate intensity aerobic exercise session combined with self-regulation on smoking delay in physically inactive smokers. Participants were 11 adults (5 males and 6 females) that completed three experimental conditions: control, exercise, and exercise using self-regulation strategies (SR). Following the experimental treatment smoking for the two exercise conditions delayed significantly more than for the control condition; in addition exercise SR delayed smoking marginally more that the plain exercise condition. Findings supported previous research that acute exercise reduces cravings to smoke, and suggests that the use of self-regulation strategies may strengthen exercise for smoking cessation interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Correlation between dynamic contrast-enhanced MRI and quantitative histopathologic microvascular parameters in organ-confined prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Niekerk, Cornelis G. van; Laak, Jeroen A.W.M. van der; Kaa, Christina A.H. de [Radboud University Medical Centre, Department of Pathology, P.O. Box 9101, Nijmegen (Netherlands); Hambrock, Thomas; Huisman, Henk-Jan; Barentsz, Jelle O. [Radboud University Medical Centre, Department of Radiology, Nijmegen (Netherlands); Witjes, J.A. [Radboud University Medical Centre, Department of Urology, Nijmegen (Netherlands)

    2014-10-15

    To correlate pharmacokinetic parameters of 3-T dynamic contrast-enhanced (DCE-)MRI with histopathologic microvascular and lymphatic parameters in organ-confined prostate cancer. In 18 patients with unilateral peripheral zone (pT2a) tumours who underwent DCE-MRI prior to radical prostatectomy (RP), the following pharmacokinetic parameters were assessed: permeability surface area volume transfer constant (K{sup trans}), extravascular extracellular volume (Ve) and rate constant (K{sub ep}). In the RP sections blood and lymph vessels were visualised immunohistochemically and automatically examined and analysed. Parameters assessed included microvessel density (MVD), area (MVA) and perimeter (MVP) as well as lymph vessel density (LVD), area (LVA) and perimeter (LVP). A negative correlation was found between age and K{sup trans} and K{sub ep} for tumour (r = -0.60, p = 0.009; r = -0.67, p = 0.002) and normal (r = -0.54, p = 0.021; r = -0.46, p = 0.055) tissue. No correlation existed between absolute values of microvascular parameters from histopathology and DCE-MRI. In contrast, the ratio between tumour and normal tissue (correcting for individual microvascularity variations) significantly correlated between K{sub ep} and MVD (r = 0.61, p = 0.007) and MVP (r = 0.54, p = 0.022). The lymphovascular parameters showed only a correlation between LVA and K{sub ep} (r = -0.66, p = 0.003). Significant correlations between DCE-MRI and histopathologic parameters were found when correcting for interpatient variations in microvascularity. (orig.)

  16. Prostate cancer transrectal HIFU ablation: detection of local recurrences using T2-weighted and dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Rouviere, Olivier; Lyonnet, Denis [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Universite de Lyon 1, Faculte de medecine Lyon Nord, Lyon (France); Inserm, U556, Lyon (France); Girouin, Nicolas; Glas, Ludivine; Ben Cheikh, Alexandre [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Universite de Lyon 1, Faculte de medecine Lyon Nord, Lyon (France); Gelet, Albert [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Inserm, U556, Lyon (France); Mege-Lechevallier, Florence [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Pathology, Lyon (France); Rabilloud, Muriel [Hospices Civils de Lyon, Department of Biostatistics, Lyon (France); Universite de Lyon 1, UMR CNRS, Laboratoire Biostatistiques-Sante, Pierre-Benite (France); Chapelon, Jean-Yves [Inserm, U556, Lyon (France)

    2010-01-15

    The objective was to evaluate T2-weighted (T2w) and dynamic contrast-enhanced (DCE) MRI in detecting local cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. Fifty-nine patients with biochemical recurrence after prostate HIFU ablation underwent T2-weighted and DCE MRI before transrectal biopsy. For each patient, biopsies were performed by two operators: operator 1 (blinded to MR results) performed random and colour Doppler-guided biopsies (''routine biopsies''); operator 2 obtained up to three cores per suspicious lesion on MRI (''targeted biopsies''). Seventy-seven suspicious lesions were detected on DCE images (n=52), T2w images (n=2) or both (n=23). Forty patients and 41 MR lesions were positive at biopsy. Of the 36 remaining MR lesions, 20 contained viable benign glands. Targeted biopsy detected more cancers than routine biopsy (36 versus 27 patients, p=0.0523). The mean percentages of positive cores per patient and of tumour invasion of the cores were significantly higher for targeted biopsies (p<0.0001). The odds ratios of the probability of finding viable cancer and viable prostate tissue (benign or malignant) at targeted versus routine biopsy were respectively 3.35 (95% CI 3.05-3.64) and 1.38 (95% CI 1.13-1.63). MRI combining T2-weighted and DCE images is a promising method for guiding post-HIFU biopsy towards areas containing recurrent cancer and viable prostate tissue. (orig.)

  17. Hemodynamic analysis of bladder tumors using T{sub 1}-dynamic contrast-enhanced fast spin-echo MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Yuki, E-mail: yukikanazawa@me.com [Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Department of Radiology, Japanese Red Cross Kyoto Daiichi Hospital, Kyoto (Japan); Miyati, Tosiaki [Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Sato, Osamu [Department of Radiology, Japanese Red Cross Kyoto Daiichi Hospital, Kyoto (Japan)

    2012-08-15

    Objectives: To evaluate the hemodynamics of bladder tumors, we developed a method to calculate change in R{sub 1} value ({Delta}R{sub 1}) from T{sub 1}-dynamic contrast-enhanced fast spin-echo magnetic resonance imaging (T{sub 1}DCE-FSE-MRI). Materials and methods: On a 1.5-T MR system, T{sub 1}DCE-FSE-MRI was performed. This study was applied to 12 patients with urinary bladder tumor, i.e. urothelial carcinoma. We compared {Delta}R{sub 1}-time and {Delta}SI-time between a peak in the {Delta}R{sub 1}-time and {Delta}SI-time curve occurred during the first pass within 60 s. Next, we assessed the slope of increase for 180 s after CA injection (Slope{sub 0-180}). Results: The mean slope of the first pass was significantly higher for bladder tumors on both the {Delta}R{sub 1}-time and the {Delta}SI-time curve compared with normal bladder walls. Moreover, a significant difference was apparent between bladder tumors and normal bladder walls on the mean Slope{sub 0-180} in the {Delta}R{sub 1}-time curve. However, no significant difference in the mean Slope{sub 0-180} was observed on the {Delta}SI-time curve between bladder tumors and normal bladder walls. Conclusion: T{sub 1}DCE-FSE-MRI offers three advantages: quantitative analysis; high-quality (i.e., artifact-free) images; and high temporal resolution even for SE images. Use of {Delta}R{sub 1} analysis with T{sub 1}DCE-FSE-MRI allows more detailed information on the hemodynamics of bladder tumors to be obtained and assists in differentiation between bladder tumors and the normal bladder wall.

  18. Joint Maximum Likelihood Time Delay Estimation of Unknown Event-Related Potential Signals for EEG Sensor Signal Quality Enhancement.

    Science.gov (United States)

    Kim, Kyungsoo; Lim, Sung-Ho; Lee, Jaeseok; Kang, Won-Seok; Moon, Cheil; Choi, Ji-Woong

    2016-06-16

    Electroencephalograms (EEGs) measure a brain signal that contains abundant information about the human brain function and health. For this reason, recent clinical brain research and brain computer interface (BCI) studies use EEG signals in many applications. Due to the significant noise in EEG traces, signal processing to enhance the signal to noise power ratio (SNR) is necessary for EEG analysis, especially for non-invasive EEG. A typical method to improve the SNR is averaging many trials of event related potential (ERP) signal that represents a brain's response to a particular stimulus or a task. The averaging, however, is very sensitive to variable delays. In this study, we propose two time delay estimation (TDE) schemes based on a joint maximum likelihood (ML) criterion to compensate the uncertain delays which may be different in each trial. We evaluate the performance for different types of signals such as random, deterministic, and real EEG signals. The results show that the proposed schemes provide better performance than other conventional schemes employing averaged signal as a reference, e.g., up to 4 dB gain at the expected delay error of 10°.

  19. A TOTP-Based Enhanced Route Optimization Procedure for Mobile IPv6 to Reduce Handover Delay and Signalling Overhead

    Directory of Open Access Journals (Sweden)

    Peer Azmat Shah

    2014-01-01

    Full Text Available Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP, video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node’s reachability at the home address and at the care-of address (home test and care-of test that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO, for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP along with verification of the mobile node via direct communication and maintaining the status of correspondent node’s compatibility. The TOTP-RO was implemented in network simulator (NS-2 and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6’s Return-Routability-based Route Optimization (RR-RO.

  20. A TOTP-based enhanced route optimization procedure for mobile IPv6 to reduce handover delay and signalling overhead.

    Science.gov (United States)

    Shah, Peer Azmat; Hasbullah, Halabi B; Lawal, Ibrahim A; Aminu Mu'azu, Abubakar; Tang Jung, Low

    2014-01-01

    Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP), video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node's reachability at the home address and at the care-of address (home test and care-of test) that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO), for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP) along with verification of the mobile node via direct communication and maintaining the status of correspondent node's compatibility. The TOTP-RO was implemented in network simulator (NS-2) and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6's Return-Routability-based Route Optimization (RR-RO).

  1. Joint Maximum Likelihood Time Delay Estimation of Unknown Event-Related Potential Signals for EEG Sensor Signal Quality Enhancement

    Science.gov (United States)

    Kim, Kyungsoo; Lim, Sung-Ho; Lee, Jaeseok; Kang, Won-Seok; Moon, Cheil; Choi, Ji-Woong

    2016-01-01

    Electroencephalograms (EEGs) measure a brain signal that contains abundant information about the human brain function and health. For this reason, recent clinical brain research and brain computer interface (BCI) studies use EEG signals in many applications. Due to the significant noise in EEG traces, signal processing to enhance the signal to noise power ratio (SNR) is necessary for EEG analysis, especially for non-invasive EEG. A typical method to improve the SNR is averaging many trials of event related potential (ERP) signal that represents a brain’s response to a particular stimulus or a task. The averaging, however, is very sensitive to variable delays. In this study, we propose two time delay estimation (TDE) schemes based on a joint maximum likelihood (ML) criterion to compensate the uncertain delays which may be different in each trial. We evaluate the performance for different types of signals such as random, deterministic, and real EEG signals. The results show that the proposed schemes provide better performance than other conventional schemes employing averaged signal as a reference, e.g., up to 4 dB gain at the expected delay error of 10°. PMID:27322267

  2. Joint Maximum Likelihood Time Delay Estimation of Unknown Event-Related Potential Signals for EEG Sensor Signal Quality Enhancement

    Directory of Open Access Journals (Sweden)

    Kyungsoo Kim

    2016-06-01

    Full Text Available Electroencephalograms (EEGs measure a brain signal that contains abundant information about the human brain function and health. For this reason, recent clinical brain research and brain computer interface (BCI studies use EEG signals in many applications. Due to the significant noise in EEG traces, signal processing to enhance the signal to noise power ratio (SNR is necessary for EEG analysis, especially for non-invasive EEG. A typical method to improve the SNR is averaging many trials of event related potential (ERP signal that represents a brain’s response to a particular stimulus or a task. The averaging, however, is very sensitive to variable delays. In this study, we propose two time delay estimation (TDE schemes based on a joint maximum likelihood (ML criterion to compensate the uncertain delays which may be different in each trial. We evaluate the performance for different types of signals such as random, deterministic, and real EEG signals. The results show that the proposed schemes provide better performance than other conventional schemes employing averaged signal as a reference, e.g., up to 4 dB gain at the expected delay error of 10°.

  3. The complementary roles of dynamic contrast-enhanced MRI and {sup 18}F-fluorodeoxyglucose PET/CT for imaging of carotid atherosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Calcagno, Claudia; Ramachandran, Sarayu; Mani, Venkatesh; Millon, Antoine [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Izquierdo-Garcia, David [Harvard University - MIT - Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States); Rosenbaum, David [Hopital Pitie Salpetriere, Paris (France); Tawakol, Ahmed [Harvard Medical School and Massachusetts General Hospital, Boston, MA (United States); Woodward, Mark [University of Sydney, George Institute, Sydney (Australia); Bucerius, Jan [Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); Rheinisch-Westfaelische Technische Hochschule Aachen, Department of Nuclear Medicine, Aachen (Germany); Moshier, Erin; Godbold, James [Mount Sinai School of Medicine, Biostatistics Shared Research Facility, New York, NY (United States); Kallend, David [F. Hoffmann-La Roche Ltd, Basel (Switzerland); Farkouh, Michael E. [Mount Sinai School of Medicine, Cardiovascular Institute, New York, NY (United States); Peter Munk Cardiac Centre and Li Ka Shing Knowledge Institute, Toronto (Canada); Fuster, Valentin [Mount Sinai School of Medicine, Cardiovascular Institute, New York, NY (United States); The Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid (Spain); Rudd, James H.F. [University of Cambridge, Division of Cardiovascular Medicine, Cambridge (United Kingdom); Fayad, Zahi A. [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, One Gustave L. Levy Place, Box 1234, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States); Mount Sinai School of Medicine, Cardiovascular Institute, New York, NY (United States)

    2013-12-15

    Inflammation and neovascularization in vulnerable atherosclerotic plaques are key features for severe clinical events. Dynamic contrast-enhanced (DCE) MRI and FDG PET are two noninvasive imaging techniques capable of quantifying plaque neovascularization and inflammatory infiltrate, respectively. However, their mutual role in defining plaque vulnerability and their possible overlap has not been thoroughly investigated. We studied the relationship between DCE-MRI and {sup 18}F-FDG PET data from the carotid arteries of 40 subjects with coronary heart disease (CHD) or CHD risk equivalent, as a substudy of the dal-PLAQUE trial (NCT00655473). The dal-PLAQUE trial was a multicenter study that evaluated dalcetrapib, a cholesteryl ester transfer protein modulator. Subjects underwent anatomical MRI, DCE-MRI and {sup 18}F-FDG PET. Only baseline imaging and biomarker data (before randomization) from dal-PLAQUE were used as part of this substudy. Our primary goal was to evaluate the relationship between DCE-MRI and {sup 18}F-FDG PET data. As secondary endpoints, we evaluated the relationship between (a) PET data and whole-vessel anatomical MRI data, and (b) DCE-MRI and matching anatomical MRI data. All correlations were estimated using a mixed linear model. We found a significant inverse relationship between several perfusion indices by DCE-MRI and {sup 18}F-FDG uptake by PET. Regarding our secondary endpoints, there was a significant relationship between plaque burden measured by anatomical MRI with several perfusion indices by DCE-MRI and {sup 18}F-FDG uptake by PET. No relationship was found between plaque composition by anatomical MRI and DCE-MRI or {sup 18}F-FDG PET metrics. In this study we observed a significant, weak inverse relationship between inflammation measured as {sup 18}F-FDG uptake by PET and plaque perfusion by DCE-MRI. Our findings suggest that there may be a complex relationship between plaque inflammation and microvascularization during the different

  4. Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings.

    Directory of Open Access Journals (Sweden)

    Bas Versluis

    Full Text Available OBJECTIVES: The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI to assess the microvascular status in patients with peripheral arterial disease (PAD and healthy controls. In addition, the reproducibility of this method in healthy controls was determined. MATERIALS AND METHODS: Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (V(p, unit: % of the anterior tibial, gastrocnemius and soleus muscles was calculated. RESULTS: V(p was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%. Differences in V(p between muscle groups were not significant. The coefficient of variation of V(p varied from 10-14% and 11-16% at interscan and interreader level, respectively. CONCLUSIONS: Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. V(p was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic biomarker for the

  5. Wind-Dragged Corolla Enhances Self-Pollination: A New Mechanism of Delayed Self-Pollination

    Science.gov (United States)

    Qu, Rongming; Li, Xiaojie; Luo, Yibo; Dong, Ming; Xu, Huanli; Chen, Xuan; Dafni, Amots

    2007-01-01

    Background and Aims Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis. Methods Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field. Key Results Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited. Conclusions This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect

  6. Cluster analysis of dynamic contrast enhanced MRI reveals tumor subregions related to locoregional relapse for cervical cancer patients.

    Science.gov (United States)

    Torheim, Turid; Groendahl, Aurora R; Andersen, Erlend K F; Lyng, Heidi; Malinen, Eirik; Kvaal, Knut; Futsaether, Cecilia M

    2016-11-01

    Solid tumors are known to be spatially heterogeneous. Detection of treatment-resistant tumor regions can improve clinical outcome, by enabling implementation of strategies targeting such regions. In this study, K-means clustering was used to group voxels in dynamic contrast enhanced magnetic resonance images (DCE-MRI) of cervical cancers. The aim was to identify clusters reflecting treatment resistance that could be used for targeted radiotherapy with a dose-painting approach. Eighty-one patients with locally advanced cervical cancer underwent DCE-MRI prior to chemoradiotherapy. The resulting image time series were fitted to two pharmacokinetic models, the Tofts model (yielding parameters K(trans) and νe) and the Brix model (ABrix, kep and kel). K-means clustering was used to group similar voxels based on either the pharmacokinetic parameter maps or the relative signal increase (RSI) time series. The associations between voxel clusters and treatment outcome (measured as locoregional control) were evaluated using the volume fraction or the spatial distribution of each cluster. One voxel cluster based on the RSI time series was significantly related to locoregional control (adjusted p-value 0.048). This cluster consisted of low-enhancing voxels. We found that tumors with poor prognosis had this RSI-based cluster gathered into few patches, making this cluster a potential candidate for targeted radiotherapy. None of the voxels clusters based on Tofts or Brix parameter maps were significantly related to treatment outcome. We identified one group of tumor voxels significantly associated with locoregional relapse that could potentially be used for dose painting. This tumor voxel cluster was identified using the raw MRI time series rather than the pharmacokinetic maps.

  7. Enhanced IMC based PID controller design for non-minimum phase (NMP) integrating processes with time delays.

    Science.gov (United States)

    Ghousiya Begum, K; Seshagiri Rao, A; Radhakrishnan, T K

    2017-03-18

    Internal model control (IMC) with optimal H2 minimization framework is proposed in this paper for design of proportional-integral-derivative (PID) controllers. The controller design is addressed for integrating and double integrating time delay processes with right half plane (RHP) zeros. Blaschke product is used to derive the optimal controller. There is a single adjustable closed loop tuning parameter for controller design. Systematic guidelines are provided for selection of this tuning parameter based on maximum sensitivity. Simulation studies have been carried out on various integrating time delay processes to show the advantages of the proposed method. The proposed controller provides enhanced closed loop performances when compared to recently reported methods in the literature. Quantitative comparative analysis has been carried out using the performance indices, Integral Absolute Error (IAE) and Total Variation (TV).

  8. Does breast MRI background parenchymal enhancement indicate metabolic activity? Qualitative and 3D quantitative computer imaging analysis.

    Science.gov (United States)

    Mema, Eralda; Mango, Victoria L; Guo, Xiaotao; Karcich, Jenika; Yeh, Randy; Wynn, Ralph T; Zhao, Binsheng; Ha, Richard S

    2017-06-24

    To investigate whether the degree of breast magnetic resonance imaging (MRI) background parenchymal enhancement (BPE) is associated with the amount of breast metabolic activity measured by breast parenchymal uptake (BPU) of 18F-FDG on positron emission tomography / computed tomography (PET/CT). An Institutional Review Board (IRB)-approved retrospective study was performed. Of 327 patients who underwent preoperative breast MRI from 1/1/12 to 12/31/15, 73 patients had 18F-FDG PET/CT evaluation performed within 1 week of breast MRI and no suspicious findings in the contralateral breast. MRI was performed on a 1.5T or 3.0T system. The imaging sequence included a triplane localizing sequence followed by sagittal fat-suppressed T2 -weighted sequence, and a bilateral sagittal T1 -weighted fat-suppressed fast spoiled gradient-echo sequence, which was performed before and three times after a rapid bolus injection (gadobenate dimeglumine, Multihance; Bracco Imaging; 0.1 mmol/kg) delivered through an IV catheter. The unaffected contralateral breast in these 73 patients underwent BPE and BPU assessments. For PET/CT BPU calculation, a 3D region of interest (ROI) was drawn around the glandular breast tissue and the maximum standardized uptake value (SUVmax ) was determined. Qualitative MRI BPE assessments were performed on a 4-point scale, in accordance with BI-RADS categories. Additional 3D quantitative MRI BPE analysis was performed using a previously published in-house technique. Spearman's correlation test and linear regression analysis was performed (SPSS, v. 24). The median time interval between breast MRI and 18F-FDG PET/CT evaluation was 3 days (range, 0-6 days). BPU SUVmax mean value was 1.6 (SD, 0.53). Minimum and maximum BPU SUVmax values were 0.71 and 4.0. The BPU SUVmax values significantly correlated with both the qualitative and quantitative measurements of BPE, respectively (r(71) = 0.59, P Qualitatively assessed high BPE group (BI-RADS 3/4) had significantly

  9. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study

    OpenAIRE

    Rosales-Lagarde, Alejandra; Jorge L Armony; del Río-Portilla, Yolanda; Trejo-Martínez, David; Conde, Ruben; Corsi-Cabrera, Maria

    2012-01-01

    Converging evidence from animal and human studies suggest that rapid eye movement (REM) sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation (REM-D) on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI). Twenty healthy subjects were randomly assigned to two groups: selective REM-D, by awakening them at each REM sleep onset, or non-rapid eye m...

  10. Enhanced emotional reactivity after selective REM sleep deprivation in humans: an fMRI study

    OpenAIRE

    Alejandra eRosales-Lagarde; Jorge L Armony; Yolanda edel Río-Portilla; David eTrejo-Martínez; Ruben eConde; Maria eCorsi-Cabrera

    2012-01-01

    Converging evidence from animal and human studies suggest that REM sleep modulates emotional processing. The aim of the present study was to explore the effects of selective REM sleep deprivation on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging (fMRI). Twenty healthy subjects were randomly assigned to two groups: selective REM sleep deprivation (REM-D), by awakening them at each REM sleep onset, or NREM sleep interrupt...

  11. Can contrast-enhanced MRI with gadoxetic acid predict liver failure and other complications after major hepatic resection?

    Science.gov (United States)

    Costa, A F; Tremblay St-Germain, A; Abdolell, M; Smoot, R L; Cleary, S; Jhaveri, K S

    2017-07-01

    To determine whether a combination of clinical factors, the future liver remnant (FLR) ratio, and hepatic uptake of gadoxetic acid can be used to predict post-hepatectomy liver failure (PHLF) and other major complications (OMC). Sixty-five consecutive patients who underwent pre-hepatectomy gadoxetic acid-enhanced magnetic resonance imaging (MRI) between October 2010 and December 2013 were included. The relative liver enhancement (RLE) of gadoxetic acid was calculated from regions of interest on MRI, and FLR ratios were obtained from computed tomography (CT). PHLF and OMC were defined by the International Study Group of Liver Surgery criteria and Clavien-Dindo grade of ≥3, respectively. Multivariate logistic regression modelling was performed to identify predictors of PHLF and OMC, including RLE, FLR ratio, age, sex, chemotherapy history, intra-operative blood loss, and intra-operative transfusion. Nine patients experienced PHLF and another nine patients experienced OMC. RLE was comparable to the FLR ratio in predicting PHLF (areas under the receiver operating characteristic [AUROC] curves, 0.665 and 0.705), but performed poorly in predicting OMCs (AUROCs, 0.556 and 0.702). Combining all clinical and imaging parameters as predictors yielded the best performing predictive models (AUROCs, 0.875 and 0.742 for PHLF and OMC, respectively). A model based on clinical parameters, the FLR ratio, and RLE of gadoxetic acid may improve pre-hepatectomy risk assessment. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  12. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T-1-weighted MRI at 3T

    DEFF Research Database (Denmark)

    Larsson, H.B.W.; Hansen, A.E.; Berg, H.K.;

    2008-01-01

    Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T-1-weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T-1-weighted fast...... field echo sequence. The input function was obtained from the internal carotid artery. An initial T-1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Pixelwise and region of interest (ROI)based calculation of cerebral perfusion (CBF) was performed...... inside the infarct core was, 9 mL/100g/min in one of the stroke patients. The other stroke patient had postischemic hyperperfusion and CBF was 140 mL/100g/min. Conclusion: Absolute values of brain perfusion can be obtained using dynamic contrast-enhanced MRI. These values correspond,to expected values...

  13. Correlation between computer-aided dynamic gadolinium-enhanced MRI assessment of inflammation and semi-quantitative synovitis and bone marrow oedema scores of the wrist in patients with rheumatoid arthritis--a cohort study

    DEFF Research Database (Denmark)

    Boesen, Mikael; Kubassova, Olga; Bouert, Rasmus;

    2012-01-01

    Objective. To test the correlation between assessment of inflammation using dynamic contrast-enhanced MRI (DCE-MRI) analysed by a novel computer-aided approach and semi-quantitative scores of synovitis and bone marrow oedema (BME) using the OMERACT-RA MRI Scoring (RAMRIS) system, in the wrist of ...

  14. Dynamic contrast enhanced MRI parameters and tumor cellularity in a rat model of cerebral glioma at 7T

    Science.gov (United States)

    Aryal, Madhava Prasad

    This dissertation mainly focuses on establishing and evaluating a stable and reproducible procedure for assessing tumor microvasculature by measuring the tissue parameters: plasma volume (vp), forward transfer constant (Ktrans), interstitial volume (ve) and distribution volume (VD), utilizing T1-weighted dynamic contrast enhanced MRI (DCE-MRI) and examining their relationship with a histo measure, cell counting. In the first part of the work, two T1-weighted DCE-MRI studies at 24 hrs time interval, using a dual-echo gradient-echo pulse sequence, were performed in 18 athymic rats implanted with U251 cerebral glioma. Using the "standard," or "consensus" model, and a separate Logan graphical analysis, T1-weighted images before, during and after the injection of a gadolinium contrast agent were used to estimate the tissue parameters mentioned above. After MRI study rats were sacrificed, and sectioned brain tissues were stained with Hematoxylin and Eosin for cell counting. Measurements in a region where a model selection process demonstrates that it can be reliably shown that contrast agent leaks from the capillary into the interstitial space quickly enough, and a concentration sufficient to measure its back flux to the vasculature, especially for Ktrans and ve, showed a remarkable stability. The combined mean parameter values in this region were: vp = (0.79+/-0.36)%, Ktrans = (2.23+/-0.71) x10-2 min -1, ve = (6.99+/-2.14)%, and VD = (7.57+/-2.32)%. In the second part of this work, the Logan graphical approach, after establishing its stability in an untreated control group, was applied to investigate a cohort of animals in which a therapeutic dose of 20 Gy radiation had been administered. In this cohort, tissue normalization appeared to be the most effective at 8 h after irradiation; this implies that the 8 hrs post-treatment time might be an ideal combination time for optimized therapeutic outcome in combined modalities. The relationship between non-invasive DCE-MRI

  15. Detection and classification of different liver lesions: Comparison of Gd-EOB-DTPA-enhanced MRI versus multiphasic spiral CT in a clinical single centre investigation

    Energy Technology Data Exchange (ETDEWEB)

    Böttcher, Joachim [Institute of Diagnostic and Interventional Radiology, SRH Clinic Gera, Str. des Friedens 122, 07548 Gera (Germany); Hansch, Andreas [Institute of Diagnostic and Interventional Radiology, Friedrich-Schiller-University, Jena University Hospital, Erlanger Allee 101, 07740 Jena (Germany); Pfeil, Alexander [Department of Internal Medicine III, Friedrich-Schiller-University, Jena University Hospital, Erlanger Allee 101, 07740 Jena (Germany); Schmidt, Peter [Institute of Diagnostic and Interventional Radiology, Friedrich-Schiller-University, Jena University Hospital, Erlanger Allee 101, 07740 Jena (Germany); Malich, Ansgar [Institute of Diagnostic Radiology, Suedharz Clinic Nordhausen, Dr. Robert-Koch-Str. 39, 99734 Nordhausen (Germany); Schneeweiss, Albrecht [Institute of Diagnostic and Interventional Radiology, Friedrich-Schiller-University, Jena University Hospital, Erlanger Allee 101, 07740 Jena (Germany); Maurer, Martin H.; Streitparth, Florian [Department of Radiology, Charité University Medicine Berlin, Campus Virchow Clinic, Augustenburger Platz 1, 13353 Berlin (Germany); Teichgräber, Ulf K. [Institute of Diagnostic and Interventional Radiology, Friedrich-Schiller-University, Jena University Hospital, Erlanger Allee 101, 07740 Jena (Germany); Renz, Diane M., E-mail: diane.renz@charite.de [Department of Radiology, Charité University Medicine Berlin, Campus Virchow Clinic, Augustenburger Platz 1, 13353 Berlin (Germany)

    2013-11-01

    Objective: To compare the diagnostic efficacy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) vs. multidetector computed tomography (MDCT) for the detection and classification of focal liver lesions, differentiated also for lesion entity and size; a separate analysis of pre- and postcontrast images as well as T2-weighted MRI sequences of focal and exclusively solid lesions was integrated. Methods: Twenty-nine patients with 130 focal liver lesions underwent MDCT (64-detector-row; contrast medium iopromide; native, arterial, portalvenous, venous phase) and MRI (1.5-T; dynamic and tissue-specific phase 20 min after application of Gd-EOB-DTPA). Hepatic lesions were verified against a standard of reference (SOR). CT and MR images were independently analysed by four blinded radiologists on an ordinal 6-point-scale, determining lesion classification and diagnostic confidence. Results: Among 130 lesions, 68 were classified as malignant and 62 as benign by SOR. The detection of malignant and benign lesions differed significantly between combined and postcontrast MRI vs. MDCT; overall detection rate was 91.5% for combined MRI and 80.4% for combined MDCT (p < 0.05). Considering all four readers together, combined MDCT achieved sensitivity of 66.2%, specificity of 79.0%, and diagnostic accuracy of 72.3%; combined MRI reached superior diagnostic efficacy: sensitivity 86.8%, specificity 94.4%, accuracy 90.4% (p < 0.05). Differentiated for lesion size, in particular lesions <20 mm revealed diagnostic benefit by MRI. Postcontrast MRI also achieved higher overall sensitivity, specificity, and accuracy compared to postcontrast MDCT for focal and exclusively solid liver lesions (p < 0.05). Conclusion: Combined and postcontrast Gd-EOB-DTPA-enhanced MRI provided significantly higher overall detection rate and diagnostic accuracy, including low inter-observer variability, compared to MDCT in a single centre study.

  16. Contrast enhanced MRI and {sup 18}F-FDG PET-CT in the assessment of multiple myeloma: A comparison of results in different phases of the disease

    Energy Technology Data Exchange (ETDEWEB)

    Spinnato, P., E-mail: paolospinnato@email.it [Imaging Division, Clinical Department of Radiological and Histocytopathological Sciences, University of Bologna, Sant’Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna (Italy); Bazzocchi, A., E-mail: abazzo@inwind.it [Imaging Division, Clinical Department of Radiological and Histocytopathological Sciences, University of Bologna, Sant’Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna (Italy); Diagnostic and Interventional Radiology, “Rizzoli” Orthopaedic Institute, Via G.C. Pupilli 1, 40136 Bologna (Italy); Brioli, A., E-mail: abrioli@libero.it [Emathology and Oncology Institute “Seragnoli”, Sant’Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna (Italy); Nanni, C., E-mail: cristina.nanni6@unibo.it [Imaging Division, Clinical Department of Radiological and Histocytopathological Sciences, University of Bologna, Sant’Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna (Italy); Zamagni, E., E-mail: e.zamagni@unibo.it [Emathology and Oncology Institute “Seragnoli”, Sant’Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna (Italy); Albisinni, U., E-mail: ugo.albisinni@ior.it [Diagnostic and Interventional Radiology, “Rizzoli” Orthopaedic Institute, Via G.C. Pupilli 1, 40136 Bologna (Italy); Cavo, M., E-mail: michele.cavo@unibo.it [Emathology and Oncology Institute “Seragnoli”, Sant’Orsola-Malpighi Hospital, Via Massarenti 9, 40138 Bologna (Italy); and others

    2012-12-15

    Objectives: The aim of our study was to compare the accuracy of contrast enhanced MRI and FDG PET-CT in the staging, treatment evaluation and follow-up of multiple myeloma. Methods: We retrospectively reviewed 210 PET-CT and 210 MRI studies of patients affected by multiple myeloma. MRI was always performed within 15 days of PET-CT. All the images have been evaluated by two expert oncologic radiologists. Results: Patient population included 81 females and 110 males (age 61.9 ± 9.9 years-old). Sixty-two patients have been evaluated at diagnosis, 58 at the end of therapies and 90 during follow-up. In 12/62 patients (19.4%) at diagnosis, differences between MRI and PET-CT findings determined changes in the staging: PET-CT was responsible for 11 down-staging (17.7%) and MRI only for one (1.6%). In 27/40 patients (67.5%) with good or complete clinical response to therapies the normalization of findings was faster for PET-CT than MRI. Ten out of 90 patients (10/90 – 11.1%) in follow-up protocol presented clinical recurrence of the disease: MRI detected active lesions in 8 of them (80.0%) and PET-CT in 5 patients (50.0%, all detected by MRI too). Conclusions: MRI achieved better results than PET-CT in the staging and in patients with multiple myeloma recurrence. PET-CT, showed prompt change of imaging findings, faster than MRI, in patients with positive response to therapy.

  17. Is there any correlation between model-based perfusion parameters and model-free parameters of time-signal intensity curve on dynamic contrast enhanced MRI in breast cancer patients?

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Boram; Kang, Doo Kyoung; Kim, Tae Hee [Ajou University School of Medicine, Department of Radiology, Suwon, Gyeonggi-do (Korea, Republic of); Yoon, Dukyong [Ajou University School of Medicine, Department of Biomedical Informatics, Suwon (Korea, Republic of); Jung, Yong Sik; Kim, Ku Sang [Ajou University School of Medicine, Department of Surgery, Suwon (Korea, Republic of); Yim, Hyunee [Ajou University School of Medicine, Department of Pathology, Suwon (Korea, Republic of)

    2014-05-15

    To find out any correlation between dynamic contrast-enhanced (DCE) model-based parameters and model-free parameters, and evaluate correlations between perfusion parameters with histologic prognostic factors. Model-based parameters (Ktrans, Kep and Ve) of 102 invasive ductal carcinomas were obtained using DCE-MRI and post-processing software. Correlations between model-based and model-free parameters and between perfusion parameters and histologic prognostic factors were analysed. Mean Kep was significantly higher in cancers showing initial rapid enhancement (P = 0.002) and a delayed washout pattern (P = 0.001). Ve was significantly lower in cancers showing a delayed washout pattern (P = 0.015). Kep significantly correlated with time to peak enhancement (TTP) (ρ = -0.33, P < 0.001) and washout slope (ρ = 0.39, P = 0.002). Ve was significantly correlated with TTP (ρ = 0.33, P = 0.002). Mean Kep was higher in tumours with high nuclear grade (P = 0.017). Mean Ve was lower in tumours with high histologic grade (P = 0.005) and in tumours with negative oestrogen receptor status (P = 0.047). TTP was shorter in tumours with negative oestrogen receptor status (P = 0.037). We could acquire general information about the tumour vascular physiology, interstitial space volume and pathologic prognostic factors by analyzing time-signal intensity curve without a complicated acquisition process for the model-based parameters. (orig.)

  18. Characteristic analysis of the optical delay in frequency response of resonant cavity enhanced (RCE) photodetectors

    Institute of Scientific and Technical Information of China (English)

    Guo Jian-Chuan; Zuo Yu-Hua; Zhang Yun; Ding Wu-Chang; Cheng Bu-Wen; Yu Jin-Zhong; Wang Qi-Ming

    2009-01-01

    With consideration of the modulation frequency of the input lightwave itself, we present a new model to calculate the quantum efficiency of RCE p-i-n photodetectors (PD) by superimposition of multiple reflected lightwaves. For the first time, the optical delay, another important factor limiting the electrical bandwidth of RCE p-i-n PD excluding the transit time of the carriers and RCd response of the photodetector, is analyzed and discussed in detail. The optical delay dominates the bandwidth of RCE p-i-n PD when its active layer is thinner than several 10 nm. These three limiting factors must be considered exactly for design of ultra-high-speed RCE p-i-n PD.

  19. Efficiency of Contrast-Enhanced Fat-Suppressed Proton Density Images for Shoulder MRI: Comparison with Contrast-enhanced Fat-suppressed T1 Weighted Image and Arthroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwan Sub; Ha, Doo Hoe; Lee, Sang Min; Yoo, Ko Eun; Kim, Jae Wha [Bundang CHA General Hospital, Pocheon (Korea, Republic of)

    2009-03-15

    This study was designed to evaluate the efficiency of contrast-enhanced fat-suppressed proton-density images (CE-FS-PDI) for shoulder MRI. We retrospectively reviewed 54 shoulder MR precontrast fat-suppressed proton-density images (FS-PDI), CE-FS-PDI and contrast-enhanced fat-suppressed T1 weighted images (CE-FS-T1WI). Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the posterior labrum, infraspinatus muscle, synovium, biceps brachii long head tendon and subcutaneous fat were analyzed on each sequence. Subsequently, 53 cases were reviewed where patients had undergone both shoulder arthroscopy and shoulder MRI. We analyzed the diagnostic agreement rates between the CE-FS-PDI and CE-FS-T1WI and the diagnostic accuracy of arthroscopically proven tears of the supraspinatus tendon. On CE-FS-PDI, the SNRs and CNRs of all structures were statistically higher than on precontrast FSPDI and CE-FS-T1WI. Diagnostic agreement rates between CE-FS-PDI and CE-FS-T1WI were 70-96% in labrums and 75-96% in rotator cuffs. The diagnostic accuracy rates for a tear of the supraspinatus tendon were 83% on CE-FS-PDI and 75% on CE-FS-T1WI, respectively. The SNR and CNR on CE-FS-PDI were increased in the shoulder structures, and the diagnostic rate for a tear of the supraspinatus tendon on CE-FS-PDI was superior as compared to CE-FS-T1WI. Therefore, CE-FS-PDI will be useful for shoulder MRI.

  20. Protein Phosphatase 2A Inhibition with LB100 Enhances Radiation-Induced Mitotic Catastrophe and Tumor Growth Delay in Glioblastoma.

    Science.gov (United States)

    Gordon, Ira K; Lu, Jie; Graves, Christian A; Huntoon, Kristin; Frerich, Jason M; Hanson, Ryan H; Wang, Xiaoping; Hong, Christopher S; Ho, Winson; Feldman, Michael J; Ikejiri, Barbara; Bisht, Kheem; Chen, Xiaoyuan S; Tandle, Anita; Yang, Chunzhang; Arscott, W Tristram; Ye, Donald; Heiss, John D; Lonser, Russell R; Camphausen, Kevin; Zhuang, Zhengping

    2015-07-01

    Protein phosphatase 2A (PP2A) is a tumor suppressor whose function is lost in many cancers. An emerging, though counterintuitive, therapeutic approach is inhibition of PP2A to drive damaged cells through the cell cycle, sensitizing them to radiotherapy. We investigated the effects of PP2A inhibition on U251 glioblastoma cells following radiation treatment in vitro and in a xenograft mouse model in vivo. Radiotherapy alone augmented PP2A activity, though this was significantly attenuated with combination LB100 treatment. LB100 treatment yielded a radiation dose enhancement factor of 1.45 and increased the rate of postradiation mitotic catastrophe at 72 and 96 hours. Glioblastoma cells treated with combination LB100 and radiotherapy maintained increased γ-H2AX expression at 24 hours, diminishing cellular repair of radiation-induced DNA double-strand breaks. Combination therapy significantly enhanced tumor growth delay and mouse survival and decreased p53 expression 3.68-fold, compared with radiotherapy alone. LB100 treatment effectively inhibited PP2A activity and enhanced U251 glioblastoma radiosensitivity in vitro and in vivo. Combination treatment with LB100 and radiation significantly delayed tumor growth, prolonging survival. The mechanism of radiosensitization appears to be related to increased mitotic catastrophe, decreased capacity for repair of DNA double-strand breaks, and diminished p53 DNA-damage response pathway activity.

  1. Differential outcomes enhance accuracy of delayed matching to sample but not resistance to change.

    Science.gov (United States)

    Nevin, John A; Ward, Ryan D; Jimenez-Gomez, Corina; Odum, Amy L; Shahan, Timothy A

    2009-01-01

    Three experiments assessed the relation between the differential outcomes effect and resistance to change of delayed matching-to-sample performance. Pigeons produced delayed matching-to-sample trials by responding on variable interval schedules in two components of a multiple schedule. In the same-outcome component, the probability of reinforcement was the same for both samples (.9 in Experiments 1 and 2, .5 in Experiment 3); in the different-outcomes component, the probability of reinforcement was .9 for one sample and .1 for the other. In all three experiments, the forgetting functions in the different-outcomes component were higher and shallower than in the same-outcomes component. When total reinforcement was greater in the same-outcomes component (Experiments 1 and 2), resistance to disruption by prefeeding, intercomponent food, extinction, or flashing lights typically was greater in that component. In Experiment 3, when total reinforcement was equated, resistance to disruption was similar across components. Thus, the level and slope of forgetting functions depended on differential reinforcement correlated with the samples, but the resistance to change of forgetting functions depended on total reinforcement in a component. Both aspects of the results can be explained by a model of delayed matching to sample performance. Copyright 2009 APA, all rights reserved.

  2. New proposal for the staging of nonalcoholic steatohepatitis: Evaluation of liver fibrosis on Gd-EOB-DTPA-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, Natsuko [Medical Affairs Diagnostic Imaging, Medical Affairs, Bayer Yakuhin, Ltd. 2-4-9, Umeda, Kita-ku, Osaka 530-0001 (Japan)], E-mail: natsuko.tsuda@bayerhealthcare.com; Okada, Masahiro; Murakami, Takamichi [Department of Radiology, Kinki University School of Medicine, Osakasayama, Osaka (Japan)

    2010-01-15

    Purpose: We investigated whether the gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI was useful for nonalcoholic steatohepatitis (NASH) staging based on the severity of liver fibrosis. Materials and methods: Twenty-one male Sprague-Dawley rats aged 7 weeks, weighing about 150 g in NASH group were fed a choline-deficient diet for 4, 7 or 10 weeks, and seven rats in the control group were fed a standard diet (n = 7). After the feeding period, the rats were subjected to contrast-enhanced MRI (2D-FLASH; TR/TE = 101/2.9 ms, flip angle 90 deg.). Gd-DTPA (0.1 mmol Gd/kg) and Gd-EOB-DTPA (0.025 mmol Gd/kg) were injected at 24-h intervals, and the speed of contrast injection was 1 mL/s. Signal intensities of the liver were measured and the relative enhancement (RE), the time of maximum RE (T{sub max}) and elimination half-life of RE (T{sub 1/2}) in the liver were compared. The fibrosis rate (%) was calculated with the following formula: fibrosis/whole area x 100. Results: The fibrosis rates of each group were as follows: 0.52, 0.79, 2.84, and 0.50% (4, 7, 10 weeks and control groups). The fibrosis rate of the 10 weeks group was significantly higher than the control and 4 or 7 weeks groups. Although there was no difference between the T{sub max} and T{sub 1/2} of each group after Gd-DTPA injection, the T{sub max} and T{sub 1/2} of the 10 weeks group were significantly prolonged in comparison with the control and 4 or 7 weeks groups after Gd-EOB-DTPA injection (p < 0.01). There was a significant correlation between the fibrosis rate and T{sub max} or T{sub 1/2} after Gd-EOB-DTPA injection (r = 0.90 or 0.97). Conclusion: It was possible to assess the progress of liver fibrosis in NASH by evaluating the signal intensity-time course on Gd-EOB-DTPA-enhanced MRI.

  3. Diffusion-weighted imaging and dynamic contrast-enhanced MRI of experimental breast cancer bone metastases – A correlation study with histology

    Energy Technology Data Exchange (ETDEWEB)

    Merz, Maximilian [Department of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Department of Hematology, Oncology and Rheumatology, Heidelberg University Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg (Germany); Seyler, Lisa; Bretschi, Maren; Semmler, Wolfhard [Department of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Bäuerle, Tobias, E-mail: tobias.baeuerle@uk-erlangen.de [Department of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Institute of Radiology, University Medical Center Erlangen, Palmsanlage 5, 90154 Erlangen (Germany)

    2015-04-15

    Purpose: To validate imaging parameters from diffusion-weighted imaging and dynamic contrast-enhanced MRI with immunohistology and to non-invasively assess microstructure of experimental breast cancer bone metastases. Materials and methods: Animals bearing breast cancer bone metastases were imaged in a clinical 1.5 T MRI scanner. HASTE sequences were performed to calculate apparent diffusion coefficients. Saturation recovery turbo FLASH sequences were conducted while infusing 0.1 mmol/l Gd–DTPA for dynamic contrast-enhanced MRI to quantify parameters amplitude A and exchange rate constant k{sub ep}. After imaging, bone metastases were analyzed immunohistologically. Results: We found correlations of the apparent diffusion coefficients from diffusion-weighted imaging with tumor cellularity as assessed with cell nuclei staining. Histological vessel maturity was correlated negatively with parameters A and k{sub ep} from dynamic contrast-enhanced MRI. Tumor size correlated inversely with cell density and vessel permeability as well as positively with mean vessel calibers. Parameters from the rim of bone metastases differed significantly from values of the center. Conclusion: In vivo diffusion-weighted imaging and dynamic contrast-enhanced MRI in experimental bone metastases provide information about tumor cellularity and vascularity and correlate well with immunohistology.

  4. Imaging-based evaluation of liver function: comparison of {sup 99m}Tc-mebrofenin hepatobiliary scintigraphy and Gd-EOB-DTPA-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Geisel, Dominik; Gebauer, Bernhard [Charite Campus Virchow-Klinikum, Department of Diagnostic and Interventional Radiology, Berlin (Germany); Luedemann, Lutz [Essen University Hospital, Department of Medical Physics, Essen (Germany); Froeling, Vera; Denecke, Timm [Charite Campus Virchow-Klinikum, Department of Diagnostic and Interventional Radiology, Berlin (Germany); Charite Campus Virchow-Klinikum, Department of Nuclear Medicine, Berlin (Germany); Malinowski, Maciej; Stockmann, Martin; Baron, Annekathrin; Seehofer, Daniel [Charite Campus Virchow-Klinikum, Department of General, Visceral and Thoracic Surgery, Berlin (Germany); Prasad, Vikas [Charite Campus Virchow-Klinikum, Department of Nuclear Medicine, Berlin (Germany)

    2015-05-01

    To compare Gd-EOB-enhanced MRI and {sup 99m}Tc-mebrofenin hepatobiliary scintigraphy (HBS) as imaging-based liver function tests for separate evaluation of right (RLL) and left liver lobe (LLL) function. Fourteen patients underwent Gd-EOB-enhanced MRI and {sup 99m}Tc-mebrofenin HBS after portal vein embolization within 24 h. Relative enhancement (RE) and hepatic uptake index (HUI) were determined from MRI; and T{sub max}, T{sub 1/2} and mebrofenin uptake were determined from HBS, all values separately for RLL and LLL. Mebrofenin uptake correlated significantly with HUI and RE for both liver lobes. There was strong correlation of mebrofenin uptake with HUI for RLL (r{sup 2} = 0.802, p = 0.001) and RE for LLL (r{sup 2} = 0.704, p = 0.005) and moderate correlation with HUI for LLL (r{sup 2} = 0.560, p = 0.037) and RE for RLL (r{sup 2} = 0.620, p = 0.018). Correlating the percentage share of RLL function derived from MRI (with HUI) with the percentage of RLL function derived from mebrofenin uptake revealed a strong correlation (r{sup 2} = 0.775, p = 0.002). Both RE and HUI correlate with mebrofenin uptake in HBS. The results suggest that Gd-EOB-enhanced MRI and {sup 99m}Tc-mebrofenin HBS may equally be used to separately determine right and left liver lobe function. (orig.)

  5. Delayed contrast enhancement imaging of a murine model for ischemia reperfusion with carbon nanotube micro-CT.

    Directory of Open Access Journals (Sweden)

    Laurel M Burk

    Full Text Available We aim to demonstrate the application of free-breathing prospectively gated carbon nanotube (CNT micro-CT by evaluating a myocardial infarction model with a delayed contrast enhancement technique. Evaluation of murine cardiac models using micro-CT imaging has historically been limited by extreme imaging requirements. Newly-developed CNT-based x-ray sources offer precise temporal resolution, allowing elimination of physiological motion through prospective gating. Using free-breathing, cardiac-gated CNT micro-CT, a myocardial infarction model can be studied non-invasively and with high resolution. Myocardial infarction was induced in eight male C57BL/6 mice aged 8-12 weeks. The ischemia reperfusion model was achieved by surgically occluding the LAD artery for 30 minutes followed by 24 hours of reperfusion. Tail vein catheters were placed for contrast administration. Iohexol 300 mgI/mL was administered followed by images obtained in diastole. Iodinated lipid blood pool contrast agent was then administered, followed with images at systole and diastole. Respiratory and cardiac signals were monitored externally and used to gate the scans of free-breathing subjects. Seven control animals were scanned using the same imaging protocol. After imaging, the heart was harvested, cut into 1mm slices and stained with TTC. Post-processing analysis was performed using ITK-Snap and MATLAB. All animals demonstrated obvious delayed contrast enhancement in the left ventricular wall following the Iohexol injection. The blood pool contrast agent revealed significant changes in cardiac function quantified by 3-D volume ejection fractions. All subjects demonstrated areas of myocardial infarct in the LAD distribution on both TTC staining and micro-CT imaging. The CNT micro-CT system aids straightforward, free-breathing, prospectively-gated 3-D murine cardiac imaging. Delayed contrast enhancement allows identification of infarcted myocardium after a myocardial ischemic

  6. Approximate Solutions of Delay Differential Equations with Constant and Variable Coefficients by the Enhanced Multistage Homotopy Perturbation Method

    Directory of Open Access Journals (Sweden)

    D. Olvera

    2015-01-01

    Full Text Available We expand the application of the enhanced multistage homotopy perturbation method (EMHPM to solve delay differential equations (DDEs with constant and variable coefficients. This EMHPM is based on a sequence of subintervals that provide approximate solutions that require less CPU time than those computed from the dde23 MATLAB numerical integration algorithm solutions. To address the accuracy of our proposed approach, we examine the solutions of several DDEs having constant and variable coefficients, finding predictions with a good match relative to the corresponding numerical integration solutions.

  7. Contrast enhancement of the cerebrospinal fluid on MRI in two cases of spirochaetal meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Good, C.D.; Jaeger, H.R. [Lysholm Radiological Department, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG (United Kingdom)

    2000-06-01

    We report two patients with meningitis due to spirochaetal infection, both of whom showed diffusely enhancing meninges around the brain and spinal cord. In addition, there was enhancement of the cerebrospinal fluid after intravenous administration of Gd-DTPA. (orig.)

  8. In-Vivo Imaging of Cell Migration Using Contrast Enhanced MRI and SVM Based Post-Processing.

    Directory of Open Access Journals (Sweden)

    Christian Weis

    Full Text Available The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of T2*-weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 μM of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods.

  9. In-Vivo Imaging of Cell Migration Using Contrast Enhanced MRI and SVM Based Post-Processing.

    Science.gov (United States)

    Weis, Christian; Hess, Andreas; Budinsky, Lubos; Fabry, Ben

    2015-01-01

    The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI) in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM) based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of T2*-weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 μM of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods.

  10. The use of error-category mapping in pharmacokinetic model analysis of dynamic contrast-enhanced MRI data.

    Science.gov (United States)

    Gill, Andrew B; Anandappa, Gayathri; Patterson, Andrew J; Priest, Andrew N; Graves, Martin J; Janowitz, Tobias; Jodrell, Duncan I; Eisen, Tim; Lomas, David J

    2015-02-01

    This study introduces the use of 'error-category mapping' in the interpretation of pharmacokinetic (PK) model parameter results derived from dynamic contrast-enhanced (DCE-) MRI data. Eleven patients with metastatic renal cell carcinoma were enrolled in a multiparametric study of the treatment effects of bevacizumab. For the purposes of the present analysis, DCE-MRI data from two identical pre-treatment examinations were analysed by application of the extended Tofts model (eTM), using in turn a model arterial input function (AIF), an individually-measured AIF and a sample-average AIF. PK model parameter maps were calculated. Errors in the signal-to-gadolinium concentration ([Gd]) conversion process and the model-fitting process itself were assigned to category codes on a voxel-by-voxel basis, thereby forming a colour-coded 'error-category map' for each imaged slice. These maps were found to be repeatable between patient visits and showed that the eTM converged adequately in the majority of voxels in all the tumours studied. However, the maps also clearly indicated sub-regions of low Gd uptake and of non-convergence of the model in nearly all tumours. The non-physical condition ve ≥ 1 was the most frequently indicated error category and appeared sensitive to the form of AIF used. This simple method for visualisation of errors in DCE-MRI could be used as a routine quality-control technique and also has the potential to reveal otherwise hidden patterns of failure in PK model applications.

  11. MRI of small bowel Crohn's disease: determining the reproducibility of bowel wall gadolinium enhancement measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sharman, A.; Zealley, I.A. [Ninewells Hospital, Dundee (United Kingdom); Greenhalgh, R.; Taylor, S.A. [University College Hospital, Department of Imaging, London (United Kingdom); Bassett, P. [Stats Consultancy, Ruislip (United Kingdom)

    2009-08-15

    This study aims to determine inter- and intra-observer variation in MRI measurements of relative bowel wall signal intensity (SI) in Crohn's disease. Twenty-one small bowel MRI examinations (11 male, mean age 40), including T1-weighted acquisitions acquired 30 to 120s post-gadolinium, were analysed. Maximal bowel wall SI (most avid, conspicuous contrast enhancement) in designated diseased segments was measured by two radiologists and two trainees using self-positioned ''free'' regions of interest (ROIs) followed by ''fixed'' ROIs chosen by one radiologist, and this procedure was repeated 1 month later. Relative enhancement (post-contrast SI minus pre-contrast SI/pre-contrast SI) was calculated. Data were analysed using Bland-Altman limits of agreement and intra-class correlation. Inter-observer agreement for relative enhancement was poor (spanning over 120%) using a free ROI - 95% limits of agreement -0.69, 0.70 and -0.47, 0.74 for radiologists and trainees, respectively, only marginally improved by use of a fixed ROI -0.60, 0.67 and -0.59, 0.49. Intra-class correlation ranged from 0.46 to 0.72. Intra-observer agreement was slightly better and optimised using a fixed ROI - 95% limits of agreement -0.52, 0.50 and -0.34, 0.28 for radiologists and trainees, respectively. Intra-class correlation ranged from 0.49 to 0.86. Relative bowel wall signal intensity measurements demonstrate wide limits of observer agreement, unrelated to reader experience but improved using fixed ROIs. (orig.)

  12. Delayed mirror visual feedback presented using a novel mirror therapy system enhances cortical activation in healthy adults.

    Science.gov (United States)

    Lee, Hsin-Min; Li, Ping-Chia; Fan, Shih-Chen

    2015-07-11

    Mirror visual feedback (MVF) generated in mirror therapy (MT) with a physical mirror promotes the recovery of hemiparetic limbs in patients with stroke, but is limited in that it cannot provide an asymmetric mode for bimanual coordination training. Here, we developed a novel MT system that can manipulate the MVF to resolve this issue. The aims of this pilot study were to examine the feasibility of delayed MVF on MT and to establish its effects on cortical activation in order to understand how it can be used for clinical applications in the future. Three conditions (no MVF, MVF, and 2-s delayed MVF) presented via our digital MT system were evaluated for their time-course effects on cortical activity by event-related desynchronization (ERD) of mu rhythm electroencephalography (EEG) during button presses in 18 healthy adults. Phasic ERD areas, defined as the areas of the relative ERD curve that were below the reference level and within -2-0 s (P0), 0-2 s (P1), and 2-4 s (P2) of the button press, were used. The overall (P0 to P2) and phasic ERD areas were higher when MVF was provided compared to when MVF was not provided for all EEG channels (C3, Cz, and C4). Phasic ERD areas in the P2 phase only increased during the delayed-MVF condition. Significant enhancement of cortical activation in the mirror neuron system and an increase in attention to the unseen limb may play major roles in the response to MVF during MT. In comparison to the no MVF condition, the higher phasic ERD areas that were observed during the P1 phase in the delayed-MVF condition indicate that the image of the still hand may have enhanced the cortical activation that occurred in response to the button press. This study is the first to achieve delayed MVF for upper-limb MT. Our approach confirms previous findings regarding the effects of MVF on cortical activation and contributes additional evidence supporting the use of this method in the future for upper-limb motor training in patients with stroke.

  13. 76 FR 45181 - Enhancing Airline Passenger Protections: Limited Delay of Effective Date for Certain Provisions

    Science.gov (United States)

    2011-07-28

    ... Office of the Secretary 14 CFR Parts 244, 250, 253, 259 and 399 RIN No. 2105-AD92 Enhancing Airline... certain requirements adopted in an April 25, 2011 final rule on enhancing airline passenger protections... boarding compensation airlines must pay to passengers bumped from flights, and the requirement to disclose...

  14. Mental simulation of drawing actions enhances delayed recall of a complex figure.

    Science.gov (United States)

    De Lucia, Natascia; Trojano, Luigi; Senese, Vincenzo Paolo; Conson, Massimiliano

    2016-10-01

    Motor simulation implies that the same motor representations involved in action execution are re-enacted during observation or imagery of actions. Neurofunctional data suggested that observation of letters or abstract paintings can elicit simulation of writing or drawing gestures. We performed four behavioural experiments on right-handed healthy participants to test whether observation of a static and complex geometrical figure implies re-enactment of drawing actions. In Experiment 1, participants had to observe the stimulus without explicit instruction (observation-only condition), while performing irrelevant finger tapping (motor dual task), or while articulating irrelevant verbal material (verbal dual task). Delayed drawing of the stimulus was less accurate in the motor dual-task (interfering with simulation of hand actions) than in verbal dual-task and observation-only conditions. In Experiment 2, delayed drawing in the observation only was as accurate as when participants encoded the stimulus by copying it; in both conditions, accuracy was higher than when participants were instructed to observe the stimulus to recall it later verbally (observe to recall), thus being discouraged from engaging motor simulation. In Experiment 3, delayed drawing was as accurate in the observation-only condition as when participants imagined copying the stimulus; accuracy in both conditions was higher than in the observe-to-recall condition. In Experiment 4, in the observe-only condition participants who observed the stimulus with their right arm hidden behind their back were significantly less accurate than participants who had their left arm hidden. These findings converge in suggesting that mere observation of a geometrical stimulus can activate motor simulation and re-enactment of drawing actions.

  15. Nerve Cross-Bridging to Enhance Nerve Regeneration in a Rat Model of Delayed Nerve Repair

    Science.gov (United States)

    2015-01-01

    There are currently no available options to promote nerve regeneration through chronically denervated distal nerve stumps. Here we used a rat model of delayed nerve repair asking of prior insertion of side-to-side cross-bridges between a donor tibial (TIB) nerve and a recipient denervated common peroneal (CP) nerve stump ameliorates poor nerve regeneration. First, numbers of retrogradely-labelled TIB neurons that grew axons into the nerve stump within three months, increased with the size of the perineurial windows opened in the TIB and CP nerves. Equal numbers of donor TIB axons regenerated into CP stumps either side of the cross-bridges, not being affected by target neurotrophic effects, or by removing the perineurium to insert 5-9 cross-bridges. Second, CP nerve stumps were coapted three months after inserting 0-9 cross-bridges and the number of 1) CP neurons that regenerated their axons within three months or 2) CP motor nerves that reinnervated the extensor digitorum longus (EDL) muscle within five months was determined by counting and motor unit number estimation (MUNE), respectively. We found that three but not more cross-bridges promoted the regeneration of axons and reinnervation of EDL muscle by all the CP motoneurons as compared to only 33% regenerating their axons when no cross-bridges were inserted. The same 3-fold increase in sensory nerve regeneration was found. In conclusion, side-to-side cross-bridges ameliorate poor regeneration after delayed nerve repair possibly by sustaining the growth-permissive state of denervated nerve stumps. Such autografts may be used in human repair surgery to improve outcomes after unavoidable delays. PMID:26016986

  16. Nerve cross-bridging to enhance nerve regeneration in a rat model of delayed nerve repair.

    Science.gov (United States)

    Gordon, Tessa; Hendry, Michael; Lafontaine, Christine A; Cartar, Holliday; Zhang, Jennifer J; Borschel, Gregory H

    2015-01-01

    There are currently no available options to promote nerve regeneration through chronically denervated distal nerve stumps. Here we used a rat model of delayed nerve repair asking of prior insertion of side-to-side cross-bridges between a donor tibial (TIB) nerve and a recipient denervated common peroneal (CP) nerve stump ameliorates poor nerve regeneration. First, numbers of retrogradely-labelled TIB neurons that grew axons into the nerve stump within three months, increased with the size of the perineurial windows opened in the TIB and CP nerves. Equal numbers of donor TIB axons regenerated into CP stumps either side of the cross-bridges, not being affected by target neurotrophic effects, or by removing the perineurium to insert 5-9 cross-bridges. Second, CP nerve stumps were coapted three months after inserting 0-9 cross-bridges and the number of 1) CP neurons that regenerated their axons within three months or 2) CP motor nerves that reinnervated the extensor digitorum longus (EDL) muscle within five months was determined by counting and motor unit number estimation (MUNE), respectively. We found that three but not more cross-bridges promoted the regeneration of axons and reinnervation of EDL muscle by all the CP motoneurons as compared to only 33% regenerating their axons when no cross-bridges were inserted. The same 3-fold increase in sensory nerve regeneration was found. In conclusion, side-to-side cross-bridges ameliorate poor regeneration after delayed nerve repair possibly by sustaining the growth-permissive state of denervated nerve stumps. Such autografts may be used in human repair surgery to improve outcomes after unavoidable delays.

  17. Quantification of synovistis by MRI: correlation between dynamic and static gadolinium-enhanced magnetic resonance imaging and microscopic and macroscopic signs of synovial inflammation

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Løvgreen-Nielsen, P;

    1998-01-01

    Dynamic and static gadolinium-diethylenetriaminepentaacetic acid(Gd-DTPA)-enhanced magnetic resonance imaging (MRI) were evaluated as measures of joint inflammation in arthritis, by a comparison with macroscopic and microscopic signs of synovitis. Furthermore, the importance of the size of the ev......Dynamic and static gadolinium-diethylenetriaminepentaacetic acid(Gd-DTPA)-enhanced magnetic resonance imaging (MRI) were evaluated as measures of joint inflammation in arthritis, by a comparison with macroscopic and microscopic signs of synovitis. Furthermore, the importance of the size...

  18. A Microfluidic Platform to design crosslinked Hyaluronic Acid Nanoparticles (cHANPs) for enhanced MRI

    Science.gov (United States)

    Russo, Maria; Bevilacqua, Paolo; Netti, Paolo Antonio; Torino, Enza

    2016-11-01

    Recent advancements in imaging diagnostics have focused on the use of nanostructures that entrap Magnetic Resonance Imaging (MRI) Contrast Agents (CAs), without the need to chemically modify the clinically approved compounds. Nevertheless, the exploitation of microfluidic platforms for their controlled and continuous production is still missing. Here, a microfluidic platform is used to synthesize crosslinked Hyaluronic Acid NanoParticles (cHANPs) in which a clinically relevant MRI-CAs, gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA), is entrapped. This microfluidic process facilitates a high degree of control over particle synthesis, enabling the production of monodisperse particles as small as 35 nm. Furthermore, the interference of Gd-DTPA during polymer precipitation is overcome by finely tuning process parameters and leveraging the use of hydrophilic-lipophilic balance (HLB) of surfactants and pH conditions. For both production strategies proposed to design Gd-loaded cHANPs, a boosting of the relaxation rate T1 is observed since a T1 of 1562 is achieved with a 10 μM of Gd-loaded cHANPs while a similar value is reached with 100 μM of the relevant clinical Gd-DTPA in solution. The advanced microfluidic platform to synthesize intravascularly-injectable and completely biocompatible hydrogel nanoparticles entrapping clinically approved CAs enables the implementation of straightforward and scalable strategies in diagnostics and therapy applications.

  19. Enhanced subject-specific resting-state network detection and extraction with fast fMRI.

    Science.gov (United States)

    Akin, Burak; Lee, Hsu-Lei; Hennig, Jürgen; LeVan, Pierre

    2017-02-01

    Resting-state networks have become an important tool for the study of brain function. An ultra-fast imaging technique that allows to measure brain function, called Magnetic Resonance Encephalography (MREG), achieves an order of magnitude higher temporal resolution than standard echo-planar imaging (EPI). This new sequence helps to correct physiological artifacts and improves the sensitivity of the fMRI analysis. In this study, EPI is compared with MREG in terms of capability to extract resting-state networks. Healthy controls underwent two consecutive resting-state scans, one with EPI and the other with MREG. Subject-level independent component analyses (ICA) were performed separately for each of the two datasets. Using Stanford FIND atlas parcels as network templates, the presence of ICA maps corresponding to each network was quantified in each subject. The number of detected individual networks was significantly higher in the MREG data set than for EPI. Moreover, using short time segments of MREG data, such as 50 seconds, one can still detect and track consistent networks. Fast fMRI thus results in an increased capability to extract distinct functional regions at the individual subject level for the same scan times, and also allow the extraction of consistent networks within shorter time intervals than when using EPI, which is notably relevant for the analysis of dynamic functional connectivity fluctuations. Hum Brain Mapp 38:817-830, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Automated scoring of regional lung perf