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Sample records for mri measures distinguish

  1. Texture descriptors to distinguish radiation necrosis from recurrent brain tumors on multi-parametric MRI

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    Tiwari, Pallavi; Prasanna, Prateek; Rogers, Lisa; Wolansky, Leo; Badve, Chaitra; Sloan, Andrew; Cohen, Mark; Madabhushi, Anant

    2014-03-01

    Di erentiating radiation necrosis (a radiation induced treatment e ect) from recurrent brain tumors (rBT) is currently one of the most clinically challenging problems in care and management of brain tumor (BT) patients. Both radiation necrosis (RN), and rBT exhibit similar morphological appearance on standard MRI making non-invasive diagnosis extremely challenging for clinicians, with surgical intervention being the only course for obtaining de nitive ground truth". Recent studies have reported that the underlying biological pathways de n- ing RN and rBT are fundamentally di erent. This strongly suggests that there might be phenotypic di erences and hence cues on multi-parametric MRI, that can distinguish between the two pathologies. One challenge is that these di erences, if they exist, might be too subtle to distinguish by the human observer. In this work, we explore the utility of computer extracted texture descriptors on multi-parametric MRI (MP-MRI) to provide alternate representations of MRI that may be capable of accentuating subtle micro-architectural di erences between RN and rBT for primary and metastatic (MET) BT patients. We further explore the utility of texture descriptors in identifying the MRI protocol (from amongst T1-w, T2-w and FLAIR) that best distinguishes RN and rBT across two independent cohorts of primary and MET patients. A set of 119 texture descriptors (co-occurrence matrix homogeneity, neighboring gray-level dependence matrix, multi-scale Gaussian derivatives, Law features, and histogram of gradient orientations (HoG)) for modeling di erent macro and micro-scale morphologic changes within the treated lesion area for each MRI protocol were extracted. Principal component analysis based variable importance projection (PCA-VIP), a feature selection method previously developed in our group, was employed to identify the importance of every texture descriptor in distinguishing RN and rBT on MP-MRI. PCA-VIP employs regression analysis to provide

  2. Resting-state BOLD networks versus task-associated functional MRI for distinguishing Alzheimer's disease risk groups.

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    Fleisher, Adam S; Sherzai, Ayesha; Taylor, Curtis; Langbaum, Jessica B S; Chen, Kewei; Buxton, Richard B

    2009-10-01

    To assess the ability of resting-state functional magnetic resonance imaging to distinguish known risk factors for AD, we evaluated 17 cognitively normal individuals with a family history of AD and at least one copy of the apolipoprotein e4 allele compared to 12 individuals who were not carriers of the APOE4 gene and did not have a family history of AD. Blood oxygen level dependent fMRI was performed evaluating encoding-associated signal and resting-state default mode network signal differences between the two risk groups. Neurocognitive testing revealed that the high risk group performed worse on category fluency testing, but the groups were equivalent on all other cognitive measures. During encoding of novel face-name pairs, there were no regions of encoding-associated BOLD activations that were different in the high risk group. Encoding-associated deactivations were greater in magnitude in the low risk group in the medial and right lateral parietal cortex, similar to findings in AD studies. The resting-state DMN analysis demonstrated nine regions in the prefrontal, orbital frontal, temporal and parietal lobes that distinguished the two risk groups. Resting-state DMN analysis could distinguish risk groups with an effect size of 3.35, compared to an effect size of 1.39 using encoding-associated fMRI techniques. Imaging of the resting state avoids performance related variability seen in activation fMRI, is less complicated to acquire and standardize, does not require radio-isotopes, and may be more effective at identifying functional pathology associated with AD risk compared to non-resting fMRI techniques.

  3. Distinguishing benign confounding treatment changes from residual prostate cancer on MRI following laser ablation

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    Litjens, G.; Huisman, H.; Elliott, R.; Shih, N.; Feldman, M.; Viswanath, S.; Fütterer, J.; Bomers, J.; Madabhushi, A.

    2014-03-01

    Laser interstitial thermotherapy (LITT) is a relatively new focal therapy technique for the ablation of localized prostate cancer. However, very little is known about the specific effects of LITT within the ablation zone and the surrounding normal tissue regions. For instance, it is important to be able to assess the extent of residual cancer within the prostate following LITT, which may be masked by thermally induced benign necrotic changes. Fortunately LITT is MRI compatible and hence this allows for quantitatively assessing LITT induced changes via multi-parametric MRI. Of course definite validation of any LITT induced changes on MRI requires confirmation via histopathology. The aim of this study was to quantitatively assess and distinguish the imaging characteristics of prostate cancer and benign confounding treatment changes following LITTon 3 Tesla multi-parametric MRI by carefully mapping the treatment related changes from the ex vivo surgically resected histopathologic specimens onto the pre-operative in vivo imaging. A better understanding of the imaging characteristics of residual disease and successfully ablated tissue might lead to improved treatment monitoring and as such patient prognosis. A unique clinical trial at the Radboud University Medical Center, in which 3 patients underwent a prostatectomy after LITT treatment, yielded ex-vivo histopathologic specimens along with pre- and post-LITT MRI. Using this data we (1) identified the computer extracted MRI signatures associated with treatment effects including benign necrotic changes and residual disease and (2) subsequently evaluated the computer extracted MRI features previously identified in distinguishing LITT induced changes in the ablated area relative to the residual disease. Towards this end first a pathologist annotated the ablated area and the residual disease on the ex-vivo histology and then we transferred the annotations to the post-LITT MRI using semi-automatic elastic registration. The

  4. Fetal ocular measurements by MRI.

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    Li, Xiao Bing; Kasprian, Gregor; Hodge, Jacqueline C; Jiang, Xiao Li; Bettelheim, Dieter; Brugger, Peter C; Prayer, Daniela

    2010-11-01

    To present fetal magnetic resonance imaging (MRI) ocular measurement ranges by gestational age (GA) in normal and growth-restricted fetuses. A total of 298 pregnant women from the 18th to the 39th week of gestation were imaged using MRI. Ocular measurements including binocular distance (BOD), interocular distance (IOD), transverse ocular diameter (OD) and anterior-posterior (AP) OD were measured. The curve estimation analyses for linear, logarithmic and quadratic models were performed. The ocular measurements of the fetuses with intrauterine growth restriction (IUGR) were compared with that of the normal fetuses. The fetal eye resembles an ellipsoid with significantly longer OD and shorter AP (t = - 22.07, p < 0.001). The quadratic model was the best model in predicting growth of the fetal BOD, IOD, OD and AP. The ocular measurements of the fetuses with IUGR were significantly different from that of the normal fetuses (BOD: t = 3.58, p < 0.001; IOD: t = 5.73, p < 0.001; OD: t = 3.52, p < 0.001; AP: t = 2.19, p < 0.05). Fetal ocular growth can be readily assessed by fetal MRI. Using the normative data provided in this study, fetal ocular anomalies may be detected. Ocular size is frequently reduced in the condition of IUGR, with potential pathologic impact on postnatal vision.

  5. P06SUPRATENTORIAL PNET IN ADULTS: MRI CAN HELP DISTINGUISH FROM GLIOBLASTOMA - DWI IS KEY

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    Eralil, George; Jones, Timothy L.; Howe, Franklyn A.; Barrick, Tom R.; MacKinnon, Andrew D.

    2014-01-01

    INTRODUCTION: Extra-pineal supratentorial primitive neuro-ectodermal tumours (sPNETs) are considered rare in adults and little is known about their radiological appearances. The most clinically relevant pre-surgical differential diagnosis is glioblastoma multiforme (GBM). We present a series of patients with sPNET over a 6 year period (2008-2014), and provide an imaging update with a review of the existing literature. METHOD: Retrospective review of CT and MRI characteristics of 7 patients with histologically proven sPNETs. Comparisons were made with similarly located and histopathologically confirmed WHO Grade 4 GBMs. RESULTS: 6 of the 7 sPNETs occurred de novo. One arose within the resection bed of a WHO Grade 1 pilocytic astrocytoma. There were 4 frontal and 3 temporal lobe incidences. Mean age was 42.8yrs (range 23 - 73 yrs, median 36 yrs). On CT the solid component of the tumour was usually hyperdense. Some of the small sPNETs contained central haemorrhage, confirmed on MRI. Larger tumours were solid/cystic. On MRI the solid component of all sPNETs was T2 hypointense, showed avid enhancement and marked restricted diffusion, typical of a high grade tumour. The degree of restricted diffusion was notably greater in the sPNET group when compared to the GBM cohort. CONCLUSION: The extreme rarity of sPNETs in adults makes for difficult interpretation of existing imaging modalities. In non-histopathologically confirmed cases, imaging could be misinterpreted as high grade glioma. However, greater restricted diffusion in sPNETs may help distinguish them from GBMs. Advanced MRI techniques and correlation with spectroscopy and molecular markers will also help in the future.

  6. 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

  7. Can early MRI distinguish between Kingella kingae and Gram-positive cocci in osteoarticular infections in young children?

    Energy Technology Data Exchange (ETDEWEB)

    Kanavaki, Aikaterini; Hanquinet, Sylviane; Merlini, Laura [Geneva University Hospital HUG, Unit of Pediatric Radiology, Geneva (Switzerland); Ceroni, Dimitri [Geneva University Hospital, Unit of Pediatric Orthopedics, Geneva (Switzerland); Tchernin, David [Geneva University Hospital, Department of Radiology, Geneva (Switzerland)

    2012-01-15

    K. kingae is a common causative organism in acute osteoarticular infections (OAIs) in children under 4 years of age. Differentiation between K. kingae and Gram-positive cocci (GPC) is of great interest therapeutically. Our aim was to identify early distinguishing MRI features of OAIs. Thirty-one children younger than 4 years of age with OAI underwent MRI at presentation. Of these, 21 were caused by K. kingae and ten by GPC. Bone and soft tissue reaction, epiphyseal cartilage involvement, bone and subperiosteal abscess formation were compared between the two groups. Interobserver agreement was measured. Bone reaction was less frequent (P=0.0066) and soft tissue reaction less severe (P=0.0087) in the K. kingae group. Epiphysis cartilage abscesses were present only in the K. kingae group (P=0.0118). No difference was found for bone abscess (P=0.1411), subperiosteal abscess (P=1) or joint effusion (P=0.4414). Interobserver agreement was good for all criteria. MRI is useful in differentiating K. kingae from GPC in OAI. Cartilaginous involvement and modest soft tissue and bone reaction suggest K. kingae. (orig.)

  8. Remarks on entanglement measures and non-local state distinguishability

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    Eisert, J [QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom); Audenaert, K [QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom); Plenio, M B [QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom)

    2003-05-23

    We investigate the properties of three entanglement measures that quantify the statistical distinguishability of a given state with the closest disentangled state that has the same reductions as the primary state. In particular, we concentrate on the relative entropy of entanglement with reversed entries. We show that this quantity is an entanglement monotone which is strongly additive, thereby demonstrating that monotonicity under local quantum operations and strong additivity are compatible in principle. In accordance with the presented statistical interpretation which is provided, this entanglement monotone, however, has the property that it diverges on pure states, with the consequence that it cannot distinguish the degree of entanglement of different pure states. We also prove that the relative entropy of entanglement with respect to the set of disentangled states that have identical reductions to the primary state is an entanglement monotone. We finally investigate the trace-norm measure and demonstrate that it is also a proper entanglement monotone.

  9. Can Asperger syndrome be distinguished from autism? An anatomic likelihood meta-analysis of MRI studies.

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    Yu, Kevin K; Cheung, Charlton; Chua, Siew E; McAlonan, Gráinne M

    2011-11-01

    The question of whether Asperger syndrome can be distinguished from autism has attracted much debate and may even incur delay in diagnosis and intervention. Accordingly, there has been a proposal for Asperger syndrome to be subsumed under autism in the forthcoming Diagnostic and Statistical Manual of Mental Disorders, fifth edition, in 2013. One approach to resolve this question has been to adopt the criterion of absence of clinically significant language or cognitive delay--essentially, the "absence of language delay." To our knowledge, this is the first meta-analysis of magnetic resonance imaging (MRI) studies of people with autism to compare absence with presence of language delay. It capitalizes on the voxel-based morphometry (VBM) approach to systematically explore the whole brain for anatomic correlates of delay and no delay in language acquisition in people with autism spectrum disorders. We conducted a systematic search for VBM MRI studies of grey matter volume in people with autism. Studies with a majority (at least 70%) of participants with autism diagnoses and a history of language delay were assigned to the autism group (n = 151, control n = 190). Those with a majority (at least 70%) of individuals with autism diagnoses and no language delay were assigned to the Asperger syndrome group (n = 149, control n = 214). We entered study coordinates into anatomic likelihood estimation meta-analysis software with sampling size weighting to compare grey matter summary maps driven by Asperger syndrome or autism. The summary autism grey matter map showed lower volumes in the cerebellum, right uncus, dorsal hippocampus and middle temporal gyrus compared with controls; grey matter volumes were greater in the bilateral caudate, prefrontal lobe and ventral temporal lobe. The summary Asperger syndrome map indicated lower grey matter volumes in the bilateral amygdala/hippocampal gyrus and prefrontal lobe, left occipital gyrus, right cerebellum, putamen and precuneus

  10. A robust classifier to distinguish noise from fMRI independent components.

    Directory of Open Access Journals (Sweden)

    Vanessa Sochat

    Full Text Available Analyzing Functional Magnetic Resonance Imaging (fMRI of resting brains to determine the spatial location and activity of intrinsic brain networks--a novel and burgeoning research field--is limited by the lack of ground truth and the tendency of analyses to overfit the data. Independent Component Analysis (ICA is commonly used to separate the data into signal and Gaussian noise components, and then map these components on to spatial networks. Identifying noise from this data, however, is a tedious process that has proven hard to automate, particularly when data from different institutions, subjects, and scanners is used. Here we present an automated method to delineate noisy independent components in ICA using a data-driven infrastructure that queries a database of 246 spatial and temporal features to discover a computational signature of different types of noise. We evaluated the performance of our method to detect noisy components from healthy control fMRI (sensitivity = 0.91, specificity = 0.82, cross validation accuracy (CVA = 0.87, area under the curve (AUC = 0.93, and demonstrate its generalizability by showing equivalent performance on (1 an age- and scanner-matched cohort of schizophrenia patients from the same institution (sensitivity = 0.89, specificity = 0.83, CVA = 0.86, (2 an age-matched cohort on an equivalent scanner from a different institution (sensitivity = 0.88, specificity = 0.88, CVA = 0.88, and (3 an age-matched cohort on a different scanner from a different institution (sensitivity = 0.72, specificity = 0.92, CVA = 0.79. We additionally compare our approach with a recently published method. Our results suggest that our method is robust to noise variations due to population as well as scanner differences, thereby making it well suited to the goal of automatically distinguishing noise from functional networks to enable investigation of human brain function.

  11. Quantitative Cerebral Blood Flow Measurements Using MRI

    OpenAIRE

    Muir, Eric R; Watts, Lora Talley; Tiwari, Yash Vardhan; Bresnen, Andrew; Timothy Q Duong

    2014-01-01

    Magnetic resonance imaging utilized as a quantitative and noninvasive method to image cerebral blood flow. The two most common techniques used to detect cerebral blood flow are dynamic susceptibility contrast (DSC) perfusion MRI and arterial spin labeling perfusion MRI. Herein we describe the use of these two techniques to measure cerebral blood flow in rodents, including methods, analysis, and important considerations when utilizing these techniques.

  12. Accuracy of MRI in Growth Plate Measurement

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    Objective. Analysis of the accuracy of growth plate thickness measurements detected on 1.5T and 7T MR images using histology sections as gold standard. Materials and Methods. Four defrosted pig tibiae were 1.5T MR scanned and one fresh tibia was 7T MR scanned. The height of the growth plate...... was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  13. Accuracy of MRI in Growth Plate Measurement

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    Objective. Analysis of the accuracy of growth plate thickness measurements detected on 1.5T and 7T MR images using histology sections as gold standard. Materials and Methods. Four defrosted pig tibiae were 1.5T MR scanned and one fresh tibia was 7T MR scanned. The height of the growth plate...... was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  14. Distinguishing cirrus cloud presence in autonomous lidar measurements

    Directory of Open Access Journals (Sweden)

    J. R. Campbell

    2014-07-01

    Full Text Available Level 2 Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP satellite-based cloud datasets from 2012 are investigated for metrics that help distinguish the cirrus cloud presence of in autonomous lidar measurements, using temperatures, heights, optical depth and phase. A thermal threshold, proposed by Sassen and Campbell (2001; SC2001 for cloud top temperature Ttop ≤ −37 °C, is evaluated vs. CALIOP algorithms that identify ice-phase cloud layers alone using depolarized backscatter. Global mean cloud top heights (11.15 vs. 10.07 km a.m.s.l., base heights (8.76 vs. 7.95 km a.m.s.l., temperatures (−58.48 °C vs. −52.18 °C and −42.40 °C vs. −38.13 °C, respectively for tops and bases and optical depths (1.18 vs. 1.23 reflect the sensitivity to these competing constraints. Over 99% of all Ttop ≤ −37 °C clouds are classified as ice by CALIOP Level 2 algorithms. Over 81% of all ice clouds correspond with Ttop ≤ −37 °C. For instruments lacking polarized measurements, and thus practical phase estimates, Ttop ≤ −37 °C proves stable for distinguishing cirrus, as opposed to the risks of glaciated liquid water cloud contamination occurring in a given sample from clouds identified at warmer temperatures. Uncertainties in temperature profiles use to collocate with lidar data (i.e., model reanalyses/sondes may justifiably relax the Ttop ≤ −37 °C threshold to include warmer cases. The ambiguity of "warm" (Ttop > −37 °C ice cloud genus cannot be reconciled completely with available measurements, however, conspicuously including phase. Cloud top heights and optical depths are evaluated as potential constraints, as functions of CALIOP-retrieved phase. However, these data provide, at best, additional constraint in regional samples, compared with temperature alone, and may exacerbate classification uncertainties overall globally.

  15. Morphometric connectivity analysis to distinguish normal, mild cognitive impaired, and Alzheimer subjects based on brain MRI

    DEFF Research Database (Denmark)

    Erleben, Lene Lillemark; Sørensen, Lauge; Mysling, Peter

    2013-01-01

    This work investigates a novel way of looking at the regions in the brain and their relationship as possible markers to classify normal control (NC), mild cognitive impaired (MCI), and Alzheimer Disease (AD) subjects. MRI scans from a subset of 101 subjects from the ADNI study at baseline was used...

  16. Measuring cardiac efficiency using PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gullberg, Grand [Lawrence Berkeley National Laboratory (United States); Aparici, Carina Mari; Brooks, Gabriel [University of California San Francisco (United States); Liu, Jing; Guccione, Julius; Saloner, David; Seo, Adam Youngho; Ordovas, Karen Gomes [Lawrence Berkeley National Laboratory (United States)

    2015-05-18

    Heart failure (HF) is a complex syndrome that is projected by the American Heart Association to cost $160 billion by 2030. In HF, significant metabolic changes and structural remodeling lead to reduced cardiac efficiency. A normal heart is approximately 20-25% efficient measured by the ratio of work to oxygen utilization (1 ml oxygen = 21 joules). The heart requires rapid production of ATP where there is complete turnover of ATP every 10 seconds with 90% of ATP produced by mitochondrial oxidative metabolism requiring substrates of approximately 30% glucose and 65% fatty acids. In our preclinical PET/MRI studies in normal rats, we showed a negative correlation between work and the influx rate constant for 18FDG, confirming that glucose is not the preferred substrate at rest. However, even though fatty acid provides 9 kcal/gram compared to 4 kcal/gram for glucose, in HF the preferred energy source is glucose. PET/MRI offers the potential to study this maladapted mechanism of metabolism by measuring work in a region of myocardial tissue simultaneously with the measure of oxygen utilization, glucose, and fatty acid metabolism and to study cardiac efficiency in the etiology of and therapies for HF. MRI is used to measure strain and a finite element mechanical model using pressure measurements is used to estimate myofiber stress. The integral of strain times stress provides a measure of work which divided by energy utilization, estimated by the production of 11CO2 from intravenous injection of 11C-acetate, provides a measure of cardiac efficiency. Our project involves translating our preclinical research to the clinical application of measuring cardiac efficiency in patients. Using PET/MRI to develop technologies for studying myocardial efficiency in patients, provides an opportunity to relate cardiac work of specific tissue regions to metabolic substrates, and measure the heterogeneity of LV efficiency.

  17. Central nervous system infectious diseases mimicking multiple sclerosis: recognizing distinguishable features using MRI

    Directory of Open Access Journals (Sweden)

    Antonio Jose da Rocha

    2013-09-01

    Full Text Available The current diagnostic criteria for multiple sclerosis (MS confirm the relevant role of magnetic resonance imaging (MRI, supporting the possibility of characterizing the dissemination in space (DIS and the dissemination in time (DIT in a single scan. To maintain the specificity of these criteria, it is necessary to determine whether T2/FLAIR visible lesions and the gadolinium enhancement can be attributed to diseases that mimic MS. Several diseases are included in the MS differential diagnosis list, including diseases with exacerbation, remitting periods and numerous treatable infectious diseases, which can mimic the MRI features of MS. We discuss the most relevant imaging features in several infectious diseases that resemble MS and examine the primary spatial distributions of lesions and the gadolinium enhancement patterns related to MS. Recognizing imaging "red flags" can be useful for the proper diagnostic evaluation of suspected cases of MS, facilitating the correct differential diagnosis by assessing the combined clinical, laboratory and MR imaging information.

  18. Measuring glomerular number from kidney MRI images

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    Thiagarajan, Jayaraman J.; Natesan Ramamurthy, Karthikeyan; Kanberoglu, Berkay; Frakes, David; Bennett, Kevin; Spanias, Andreas

    2016-03-01

    Measuring the glomerular number in the entire, intact kidney using non-destructive techniques is of immense importance in studying several renal and systemic diseases. Commonly used approaches either require destruction of the entire kidney or perform extrapolation from measurements obtained from a few isolated sections. A recent magnetic resonance imaging (MRI) method, based on the injection of a contrast agent (cationic ferritin), has been used to effectively identify glomerular regions in the kidney. In this work, we propose a robust, accurate, and low-complexity method for estimating the number of glomeruli from such kidney MRI images. The proposed technique has a training phase and a low-complexity testing phase. In the training phase, organ segmentation is performed on a few expert-marked training images, and glomerular and non-glomerular image patches are extracted. Using non-local sparse coding to compute similarity and dissimilarity graphs between the patches, the subspace in which the glomerular regions can be discriminated from the rest are estimated. For novel test images, the image patches extracted after pre-processing are embedded using the discriminative subspace projections. The testing phase is of low computational complexity since it involves only matrix multiplications, clustering, and simple morphological operations. Preliminary results with MRI data obtained from five kidneys of rats show that the proposed non-invasive, low-complexity approach performs comparably to conventional approaches such as acid maceration and stereology.

  19. Interpolatability distinguishes LOCC from separable von Neumann measurements

    Energy Technology Data Exchange (ETDEWEB)

    Childs, Andrew M.; Leung, Debbie; Mančinska, Laura [Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Ozols, Maris [Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); IBM TJ Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2013-11-15

    Local operations with classical communication (LOCC) and separable operations are two classes of quantum operations that play key roles in the study of quantum entanglement. Separable operations are strictly more powerful than LOCC, but no simple explanation of this phenomenon is known. We show that, in the case of von Neumann measurements, the ability to interpolate measurements is an operational principle that sets apart LOCC and separable operations.

  20. Comparison of (123)I-MIBG myocardial scintigraphy, brain perfusion SPECT, and voxel-based MRI morphometry for distinguishing between dementia with Lewy bodies and Alzheimer's disease.

    Science.gov (United States)

    Inui, Yoshitaka; Toyama, Hiroshi; Manabe, Yuta; Sarai, Masayoshi; Iwata, Nakao

    2014-10-01

    This study aimed to compare the diagnostic value of (123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy, N-isopropyl-p[(123)I]iodoamphetamine (IMP) brain perfusion single-photon emission computed tomography (SPECT), and brain magnetic resonance imaging (MRI) voxel-based morphometry (VBM) for the differentiation of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD). Thirty-five and 34 patients with probable DLB and probable AD, respectively, were enrolled. All patients underwent (123)I-MIBG myocardial scintigraphy, (123)I-IMP brain perfusion SPECT, and brain MRI. For (123)I-MIBG imaging, we calculated early and delayed heart-to-mediastinum (H/M) uptake ratios. Three-dimensional stereotactic surface projections (3D-SSP) were used to analyze the results of (123)I-IMP SPECT. VBM with statistical parametric mapping 8 plus diffeomorphic anatomical registration using exponentiated Lie algebra (DARTEL) was used to analyze the brain MRI data. The area under the receiver operating characteristic curves (AUC) for discriminating DLB and AD was highest (0.882) for the delayed H/M ratio on (123)I-MIBG scintigraphy. AUC for z-score measurement in the occipital lobe was 0.818 and that for the extent of gray matter (GM) atrophy in the whole brain was 0.788. AUC for the combination of 3D-SSP and VBM analysis was 0.836. The respective sensitivities and specificities for distinguishing DLB from AD were 97.1 and 100 % for the delayed H/M ratio using (123)I-MIBG scintigraphy; 88.6 and 73.5 % for the occipital lobe z-score using 3D-SSP analysis; 85.7 and 64.7 % for the extent of whole brain GM atrophy using voxel-based MRI morphometry; and 91.4 and 76.5 % for the combination of 3D-SSP analysis and VBM. (123)I-MIBG myocardial scintigraphy was superior to brain perfusion SPECT and brain MRI using an advanced statistical technique to differentiate DLB and AD.

  1. Distinguishing Functional DNA Words; A Method for Measuring Clustering Levels

    Science.gov (United States)

    Moghaddasi, Hanieh; Khalifeh, Khosrow; Darooneh, Amir Hossein

    2017-01-01

    Functional DNA sub-sequences and genome elements are spatially clustered through the genome just as keywords in literary texts. Therefore, some of the methods for ranking words in texts can also be used to compare different DNA sub-sequences. In analogy with the literary texts, here we claim that the distribution of distances between the successive sub-sequences (words) is q-exponential which is the distribution function in non-extensive statistical mechanics. Thus the q-parameter can be used as a measure of words clustering levels. Here, we analyzed the distribution of distances between consecutive occurrences of 16 possible dinucleotides in human chromosomes to obtain their corresponding q-parameters. We found that CG as a biologically important two-letter word concerning its methylation, has the highest clustering level. This finding shows the predicting ability of the method in biology. We also proposed that chromosome 18 with the largest value of q-parameter for promoters of genes is more sensitive to dietary and lifestyle. We extended our study to compare the genome of some selected organisms and concluded that the clustering level of CGs increases in higher evolutionary organisms compared to lower ones. PMID:28128320

  2. Distinguishing Functional DNA Words; A Method for Measuring Clustering Levels

    Science.gov (United States)

    Moghaddasi, Hanieh; Khalifeh, Khosrow; Darooneh, Amir Hossein

    2017-01-01

    Functional DNA sub-sequences and genome elements are spatially clustered through the genome just as keywords in literary texts. Therefore, some of the methods for ranking words in texts can also be used to compare different DNA sub-sequences. In analogy with the literary texts, here we claim that the distribution of distances between the successive sub-sequences (words) is q-exponential which is the distribution function in non-extensive statistical mechanics. Thus the q-parameter can be used as a measure of words clustering levels. Here, we analyzed the distribution of distances between consecutive occurrences of 16 possible dinucleotides in human chromosomes to obtain their corresponding q-parameters. We found that CG as a biologically important two-letter word concerning its methylation, has the highest clustering level. This finding shows the predicting ability of the method in biology. We also proposed that chromosome 18 with the largest value of q-parameter for promoters of genes is more sensitive to dietary and lifestyle. We extended our study to compare the genome of some selected organisms and concluded that the clustering level of CGs increases in higher evolutionary organisms compared to lower ones.

  3. MRI of superficial soft tissue masses: analysis of features useful in distinguishing between benign and malignant lesions

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    Calleja, Michele; Dimigen, Marion; Saifuddin, Asif [Royal National Orthopaedic Hospital, Stanmore (United Kingdom)

    2012-12-15

    To identify the MRI features of superficial soft tissue masses, that may allow differentiation between malignant and non-malignant lesions. A total of 136 consecutive patients referred to a supra-regional musculoskeletal oncology center over a 10-year period with the diagnosis of a superficial soft tissue mass were included in this retrospective study. Features analyzed included patient demographics, lesion size, MRI signal characteristics, margins, lobulation, hemorrhage, necrosis, fascial edema, relationship to the fascia, as well as involvement of the skin. Comparison was then made with the final histological diagnosis. Of the patients reviewed, 58 were male and 78 were female, and the mean age was 49.9 years. The mean age for malignant lesions was 57.9 years, and that for non-neoplastic and benign conditions 41.9 years (p < 0.001). A significant relationship was identified between malignancy and lobulation (p < 0.01), hemorrhage (p < 0.001), fascial edema (p < 0.001), hemorrhage (p < 0.0001) and necrosis (p < 0.001). The relationship between skin thickening and skin contact and malignancy was also found to be significant. However, size was not found to be an important determining factor for malignancy, with a significant proportion of malignant superficial sarcomas measuring less than 5 cm in maximal diameter. This study has shown that a significant proportion of malignant superficial sarcomas measured less than 5 cm in maximal diameter. Fascial edema, skin thickening, skin contact, hemorrhage, and necrosis were found to be highly significant factors indicative of malignancy. Lobulation and peritumoral edema were also significant MRI features. (orig.)

  4. Facilitating cartilage volume measurement using MRI

    Energy Technology Data Exchange (ETDEWEB)

    Maataoui, Adel, E-mail: adel.maataoui@gmx.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Gurung, Jessen, E-mail: jessen.gurung@gmx.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Ackermann, Hanns, E-mail: h.ackermann@add.uni-frankfurt.d [Institute for Epidemiology and Medical Statistics, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Abolmaali, Nasreddin [Biological and Molecular Imaging, ZIK OncoRay - Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); Kafchitsas, Konstantinos [Department of Orthopedics and Orthopedic Surgery, Johannes Gutenberg University, Langenbeckstrasse 1, 55131 Mainz (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Khan, M. Fawad, E-mail: fawad@gmx.d [Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

    2010-08-15

    Purpose: To compare quantitative cartilage volume measurement (CVM) using different slice thicknesses. Materials and methods: Ten knees were scanned with a 1.5 T MRI (Sonata, Siemens, Erlangen, Germany) using a 3D gradient echo sequence (FLASH, fast low-angle shot). Cartilage volume of the medial and lateral tibial plateau was measured by two independent readers in 1.5 mm, 3.0 mm and 5.0 mm slices using the Argus software application. Accuracy and time effectiveness served as control parameters. Results: Determining cartilage volume, time for calculation diminished for the lateral tibial plateau from 384.6 {+-} 127.7 s and 379.1 {+-} 117.6 s to 214.9 {+-} 109.9 s and 213.9 {+-} 102.2 s to 122.1 {+-} 60.1 s and 126.8 {+-} 56.2 s and for the medial tibial plateau from 465.0 {+-} 147.7 s and 461.8 {+-} 142.7 s to 214.0 {+-} 67.9 s and 208.9 {+-} 66.2 s to 132.6 {+-} 41.5 s and 130.6 {+-} 42.0 s measuring 1.5 mm, 3 mm and 5 mm slices, respectively. No statistically significant difference between cartilage volume measurements was observed (p > 0.05) while very good inter-reader correlation was evaluated. Conclusion: CVM using 1.5 mm slices provides no higher accuracy than cartilage volume measurement in 5 mm slices while an overall time saving up to 70% is possible.

  5. Dynamic contrast-enhanced MRI in patients with muscle-invasive transitional cell carcinoma of the bladder can distinguish between residual tumour and post-chemotherapy effect

    Energy Technology Data Exchange (ETDEWEB)

    Donaldson, Stephanie B., E-mail: Stephanie.donaldson1@nhs.net [School of Cancer and Enabling Sciences, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom); Bonington, Suzanne C., E-mail: suzi.bonington@christie.nhs.uk [Department of Radiology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom); Kershaw, Lucy E., E-mail: lucy.kershaw@christie.nhs.uk [Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom); Cowan, Richard, E-mail: richard.cowan@christie.nhs.uk [Department of Clinical Oncology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom); Lyons, Jeanette, E-mail: jeanette.lyons@christie.nhs.uk [Department of Clinical Oncology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom); Elliott, Tony, E-mail: tony.elliott@christie.nhs.uk [Department of Clinical Oncology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom); Carrington, Bernadette M., E-mail: bernadette.carrington@christie.nhs.uk [Department of Radiology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom)

    2013-12-01

    Introduction: Treatment of muscle-invasive bladder cancer with chemotherapy results in haemorrhagic inflammation, mimicking residual tumour on conventional MR images and making interpretation difficult. The aim of this study was to use dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to estimate descriptive and tracer kinetic parameters post-neoadjuvant chemotherapy and to investigate whether parameters differed in areas of residual tumour and chemotherapy-induced haemorrhagic inflammation (treatment effect, Tr-Eff). Methods and materials: Twenty-one patients underwent DCE-MRI scans with 2.5 s temporal resolution before and following neoadjuvant chemotherapy. Regions-of-interest (ROIs) were defined in areas suspicious of residual tumour on T{sub 2}-weighted MRI scans. Data were analysed semi-quantitatively and with a two-compartment exchange model to obtain parameters including relative signal intensity (rSI{sub 80s}) and plasma perfusion (F{sub p}) respectively. The bladder was subsequently examined histologically after cystectomy for evidence of residual tumour and/or Tr-Eff. Differences in parameters measured in areas of residual tumour and Tr-Eff were examined using Student's t-test. Results: Twenty-four abnormal sites were defined after neoadjuvant chemotherapy. On pathology, 10 and 14 areas were identified as residual tumour and Tr-Eff respectively. Median rSI{sub 80s} and F{sub p} were significantly higher in areas of residual tumour than Tr-Eff (rSI{sub 80s} = 2.9 vs 1.7, p < 0.001; F{sub p} = 20.7 vs 9.1 ml/100 ml/min, p = 0.03). The sensitivity and specificity for differentiating residual tumour from Tr-Eff were 70% and 100% (rSI{sub 80s}), 60% and 86% (F{sub p}), and 75% and 100% when combined. Conclusion: DCE-MRI parameters obtained post-treatment are capable of distinguishing between residual tumour and treatment effect in patients treated for bladder cancer with neoadjuvant chemotherapy.

  6. Distinct laterality alterations distinguish mild cognitive impairment and Alzheimer's disease from healthy aging: statistical parametric mapping with high resolution MRI.

    Science.gov (United States)

    Long, Xiaojing; Zhang, Lijuan; Liao, Weiqi; Jiang, Chunxiang; Qiu, Bensheng

    2013-12-01

    Laterality of human brain varies under healthy aging and diseased conditions. The alterations in hemispheric asymmetry may embed distinct biomarkers linked to the disease dynamics. Statistical parametric mapping based on high-resolution magnetic resonance imaging (MRI) and image processing techniques have allowed automated characterization of morphological features across the entire brain. In this study, 149 subjects grouped in healthy young, healthy elderly, mild cognitive impairment (MCI), and Alzheimer's disease (AD) were investigated using multivariate analysis for regional cerebral laterality indexed by surface area, curvature index, cortical thickness, and subjacent white matter volume measured on high-resolution MR images. Asymmetry alteration of MCI and AD were characterized by marked region-specific reduction, while healthy elderly featured a distinct laterality shift in the limbic system in addition to regional asymmetry loss. Lack of the laterality shift in limbic system and early loss of asymmetry in entorhinal cortex may be biomarkers to identify preclinical AD among other dementia. Multivariate analysis of hemispheric asymmetry may provide information helpful for monitoring the disease progress and improving the management of MCI and AD.

  7. Distinguishing Between Related and Unrelated International Geographic Diversification: A Comprehensive Measure of Global Diversification

    OpenAIRE

    Sushil Vachani

    1991-01-01

    This paper argues that it is important to distinguish between related and unrelated international geographic diversification when measuring impact of diversification on performance. It then extends the Jacquemin-Berry entropy measure to propose a comprehensive measure of global diversification that comprises related and unrelated product diversification. It suggests a classification of firms based on diversification strategies and proposes hypotheses for future research.© 1991 JIBS. Journal o...

  8. Accuracy of MRI-based Magnetic Susceptibility Measurements

    Science.gov (United States)

    Russek, Stephen; Erdevig, Hannah; Keenan, Kathryn; Stupic, Karl

    Magnetic Resonance Imaging (MRI) is increasingly used to map tissue susceptibility to identify microbleeds associated with brain injury and pathologic iron deposits associated with neurologic diseases such as Parkinson's and Alzheimer's disease. Field distortions with a resolution of a few parts per billion can be measured using MRI phase maps. The field distortion map can be inverted to obtain a quantitative susceptibility map. To determine the accuracy of MRI-based susceptibility measurements, a set of phantoms with paramagnetic salts and nano-iron gels were fabricated. The shapes and orientations of features were varied. Measured susceptibility of 1.0 mM GdCl3 solution in water as a function of temperature agreed well with the theoretical predictions, assuming Gd+3 is spin 7/2. The MRI susceptibility measurements were compared with SQUID magnetometry. The paramagnetic susceptibility sits on top of the much larger diamagnetic susceptibility of water (-9.04 x 10-6), which leads to errors in the SQUID measurements. To extract out the paramagnetic contribution using standard magnetometry, measurements must be made down to low temperature (2K). MRI-based susceptometry is shown to be as or more accurate than standard magnetometry and susceptometry techniques.

  9. Diagnostic value of combined versus individual MRI parameters in distinguishing adenomatous from non-adenomatous adrenal lesions in cancer patients

    Directory of Open Access Journals (Sweden)

    Sally Emad-Eldin

    2014-09-01

    Conclusion: The most specific predictors for adrenal mass characterization were CSI signal drop and Gd-DTPA enhancement characteristics. Combining the MR parameters did not prove superior to those two individual parameters, however it yielded a valuable diagnostic protocol for distinguishing the adrenal masses, considering that size criterion should not be used as an individual discriminator.

  10. Diagnostic performance of CT and MRI in distinguishing intraductal papillary neoplasm of the bile duct from cholangiocarcinoma with intraductal papillary growth

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yubao; Zhong, Xiaomei; Yan, Lifen; Zheng, Junhui; Liu, Zaiyi; Liang, Changhong [Guangdong Academy of Medical Sciences, Department of Radiology, Guangdong General Hospital, Guangzhou (China)

    2015-07-15

    We aimed to evaluate the diagnostic performance of CT and MRI for distinguishing intraductal papillary neoplasm of the bile duct (IPNB) from cholangiocarcinoma (CC) with intraductal papillary growth (IPG). Forty-two patients with either IPNB or CC with IPG proven by histopathology were independently reviewed in retrospect. Strict criteria for diagnosis of IPNB included presence of the designated imaging features as follows: local dilatation of the bile duct, nodule within the dilated bile duct, growing along the interior wall of bile duct. Any lesion that was not consistent with the criteria was classified as CC with IPG. Sensitivity, specificity, positive and negative predictive values for characterization of IPNB were calculated, and k test was used to assess the level of agreement. Two imaging reviewers correctly identified 21 of 26 (80.8 %) and 22 of 26 (84.6 %) IPNB cases, respectively. Alternatively, they correctly identified 14 of 16 (87.5 %) and 15 of 16 (93.8 %) CC with IPG, respectively. Agreement between the two reviewers was perfect (k = 0.81) for the diagnosis of IPNB and differentiation from CC with IPG. By using our designated diagnostic criteria of CT and MRI, IPNB can be accurately identified and possible to be distinguished from CC with IPG. (orig.)

  11. Lack of utility of measuring serum bilirubin concentration in distinguishing perforation status of pediatric appendicitis.

    Science.gov (United States)

    Bonadio, William; Bruno, Santina; Attaway, David; Dharmar, Logesh; Tam, Derek; Homel, Peter

    2017-06-01

    Pediatric appendicitis is a common, potentially serious condition. Determining perforation status is crucial to planning effective management. Determine the efficacy of serum total bilirubin concentration [STBC] in distinguishing perforation status in children with appendicitis. Retrospective review of 257 cases of appendicitis who received abdominal CT scan and measurement of STBC. There were 109 with perforation vs 148 without perforation. Although elevated STBC was significantly more common in those with [36%] vs without perforation [22%], the mean difference in elevated values between groups [0.1mg/dL] was clinically insignificant. Higher degrees of hyperbilirubinemia [>2mg/dL] were rarely encountered [5%]. Predictive values for elevated STBC in distinguishing perforation outcome were imprecise [sensitivity 38.5%, specificity 78.4%, PPV 56.8%, NPV 63.4%]. ROC curve analysis of multiple clinical and other laboratory factors for predicting perforation status was unenhanced by adding the STBC variable. Specific analysis of those with perforated appendicitis and percutaneously-drained intra-abdominal abscess which was culture-positive for Escherichia coli showed an identical rate of STBC elevation compared to all with perforation. The routine measurement of STBC does not accurately distinguish perforation status in children with appendicitis, nor discern infecting organism in those with perforation and intra-abdominal abscess. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Towards a physiology-based measure of pain: patterns of human brain activity distinguish painful from non-painful thermal stimulation.

    Directory of Open Access Journals (Sweden)

    Justin E Brown

    Full Text Available Pain often exists in the absence of observable injury; therefore, the gold standard for pain assessment has long been self-report. Because the inability to verbally communicate can prevent effective pain management, research efforts have focused on the development of a tool that accurately assesses pain without depending on self-report. Those previous efforts have not proven successful at substituting self-report with a clinically valid, physiology-based measure of pain. Recent neuroimaging data suggest that functional magnetic resonance imaging (fMRI and support vector machine (SVM learning can be jointly used to accurately assess cognitive states. Therefore, we hypothesized that an SVM trained on fMRI data can assess pain in the absence of self-report. In fMRI experiments, 24 individuals were presented painful and nonpainful thermal stimuli. Using eight individuals, we trained a linear SVM to distinguish these stimuli using whole-brain patterns of activity. We assessed the performance of this trained SVM model by testing it on 16 individuals whose data were not used for training. The whole-brain SVM was 81% accurate at distinguishing painful from non-painful stimuli (p<0.0000001. Using distance from the SVM hyperplane as a confidence measure, accuracy was further increased to 84%, albeit at the expense of excluding 15% of the stimuli that were the most difficult to classify. Overall performance of the SVM was primarily affected by activity in pain-processing regions of the brain including the primary somatosensory cortex, secondary somatosensory cortex, insular cortex, primary motor cortex, and cingulate cortex. Region of interest (ROI analyses revealed that whole-brain patterns of activity led to more accurate classification than localized activity from individual brain regions. Our findings demonstrate that fMRI with SVM learning can assess pain without requiring any communication from the person being tested. We outline tasks that should be

  13. Mapping three-dimensional oil distribution with π-EPI MRI measurements at low magnetic field

    Science.gov (United States)

    Li, Ming; Xiao, Dan; Romero-Zerón, Laura; Marica, Florea; MacMillan, Bryce; Balcom, Bruce J.

    2016-08-01

    Magnetic resonance imaging (MRI) is a robust tool to image oil saturation distribution in rock cores during oil displacement processes. However, a lengthy measurement time for 3D measurements at low magnetic field can hinder monitoring the displacement. 1D and 2D MRI measurements are instead often undertaken to monitor the oil displacement since they are faster. However, 1D and 2D images may not completely reflect the oil distribution in heterogeneous rock cores. In this work, a high-speed 3D MRI technique, π Echo Planar Imaging (π-EPI), was employed at 0.2 T to monitor oil displacement. Centric scan interleaved sampling with view sharing in k-t space was employed to improve the temporal resolution of the π-EPI measurements. A D2O brine was employed to distinguish the hydrocarbon and water phases. A relatively homogenous glass bead pack and a heterogeneous Spynie core plug were employed to show different oil displacement behaviors. High quality 3D images were acquired with π-EPI MRI measurements. Fluid quantification with π-EPI compared favorably with FID, CPMG, 1D-DHK-SPRITE, 3D Fast Spin Echo (FSE) and 3D Conical SPRITE measurements. π-EPI greatly reduced the gradient duty cycle and improved sensitivity, compared to FSE and Conical SPRITE measurements, enabling dynamic monitoring of oil displacement processes. For core plug samples with sufficiently long lived T2, T2∗, π-EPI is an ideal method for rapid 3D saturation imaging.

  14. Triphasic MRI of pelvic organ descent: sources of measurement error

    Energy Technology Data Exchange (ETDEWEB)

    Morren, Geert L. [Bowel and Digestion Centre, The Oxford Clinic, 38 Oxford Terrace, Christchurch (New Zealand)]. E-mail: geert_morren@hotmail.com; Balasingam, Adrian G. [Christchurch Radiology Group, P.O. Box 21107, 4th Floor, Leicester House, 291 Madras Street, Christchurch (New Zealand); Wells, J. Elisabeth [Department of Public Health and General Medicine, Christchurch School of Medicine, St. Elmo Courts, Christchurch (New Zealand); Hunter, Anne M. [Christchurch Radiology Group, P.O. Box 21107, 4th Floor, Leicester House, 291 Madras Street, Christchurch (New Zealand); Coates, Richard H. [Christchurch Radiology Group, P.O. Box 21107, 4th Floor, Leicester House, 291 Madras Street, Christchurch (New Zealand); Perry, Richard E. [Bowel and Digestion Centre, The Oxford Clinic, 38 Oxford Terrace, Christchurch (New Zealand)

    2005-05-01

    Purpose: To identify sources of error when measuring pelvic organ displacement during straining using triphasic dynamic magnetic resonance imaging (MRI). Materials and methods: Ten healthy nulliparous woman underwent triphasic dynamic 1.5 T pelvic MRI twice with 1 week between studies. The bladder was filled with 200 ml of a saline solution, the vagina and rectum were opacified with ultrasound gel. T2 weighted images in the sagittal plane were analysed twice by each of the two observers in a blinded fashion. Horizontal and vertical displacement of the bladder neck, bladder base, introitus vaginae, posterior fornix, cul-de sac, pouch of Douglas, anterior rectal wall, anorectal junction and change of the vaginal axis were measured eight times in each volunteer (two images, each read twice by two observers). Variance components were calculated for subject, observer, week, interactions of these three factors, and pure error. An overall standard error of measurement was calculated for a single observation by one observer on a film from one woman at one visit. Results: For the majority of anatomical reference points, the range of displacements measured was wide and the overall measurement error was large. Intra-observer error and week-to-week variation within a subject were important sources of measurement error. Conclusion: Important sources of measurement error when using triphasic dynamic MRI to measure pelvic organ displacement during straining were identified. Recommendations to minimize those errors are made.

  15. Flow measurements in cardiac MRI; Flussmessungen in der kardialen MRT

    Energy Technology Data Exchange (ETDEWEB)

    Lotz, J. [Medizinische Hochschule Hannover, Institut fuer Diagnostische Radiologie, Hannover (Germany)

    2007-04-15

    Phase-contrast flow measurements have become an established method in cardiac MRI. The quantification of intra- and extracardiac shunt volumes as well as the evaluation of valvular disease and aortic coarctation have proved their clinical usefulness. There are some rules that have to be followed when performing and analyzing phase-contrast flow measurements. With these rules in mind, quantitative phase-contrast flow measurements are a reliable and precise method for clinical use of cardiac MRI. (orig.) [German] Flussmessungen gehoeren zum Standardrepertoire der MRT des Herzens. Dabei stehen die Quantifizierungen intra- und extrakardialer Shuntvolumina sowie von Klappenvitien im Vordergrund. Aber auch die Abschaetzung von Stenosen, beispielsweise des Aortenisthmus v. a. ueber einen assoziierten Kollateralfluss, sind klinisch akzeptiert. Bei der Planung und Auswertung einer Phasenkontrastflussmessung muessen einige Regeln beachtet werden, um fehlerhafte Ergebnisse zu vermeiden. Dann aber ist die Phasenkontrastflussmessung eine wertvolle Ergaenzung fuer die taegliche Routine in der Herzbildgebung. (orig.)

  16. Performance comparison of deep learning and segmentation-based radiomic methods in the task of distinguishing benign and malignant breast lesions on DCE-MRI

    Science.gov (United States)

    Antropova, Natasha; Huynh, Benjamin; Giger, Maryellen

    2017-03-01

    Intuitive segmentation-based CADx/radiomic features, calculated from the lesion segmentations of dynamic contrast-enhanced magnetic resonance images (DCE-MRIs) have been utilized in the task of distinguishing between malignant and benign lesions. Additionally, transfer learning with pre-trained deep convolutional neural networks (CNNs) allows for an alternative method of radiomics extraction, where the features are derived directly from the image data. However, the comparison of computer-extracted segmentation-based and CNN features in MRI breast lesion characterization has not yet been conducted. In our study, we used a DCE-MRI database of 640 breast cases - 191 benign and 449 malignant. Thirty-eight segmentation-based features were extracted automatically using our quantitative radiomics workstation. Also, 2D ROIs were selected around each lesion on the DCE-MRIs and directly input into a pre-trained CNN AlexNet, yielding CNN features. Each method was investigated separately and in combination in terms of performance in the task of distinguishing between benign and malignant lesions. Area under the ROC curve (AUC) served as the figure of merit. Both methods yielded promising classification performance with round-robin cross-validated AUC values of 0.88 (se =0.01) and 0.76 (se=0.02) for segmentationbased and deep learning methods, respectively. Combination of the two methods enhanced the performance in malignancy assessment resulting in an AUC value of 0.91 (se=0.01), a statistically significant improvement over the performance of the CNN method alone.

  17. Distinguishing specific sexual and general emotional effects in fMRI-subcortical and cortical arousal during erotic picture viewing.

    Science.gov (United States)

    Walter, Martin; Bermpohl, Felix; Mouras, Harold; Schiltz, Kolja; Tempelmann, Claus; Rotte, Michael; Heinze, Hans Jochen; Bogerts, Bernhard; Northoff, Georg

    2008-05-01

    Sexual activity involves excitement with high arousal and pleasure as typical features of emotions. Brain activations specifically related to erotic feelings and those related to general emotional processing are therefore hard to disentangle. Using fMRI in 21 healthy subjects (11 males and 10 females), we investigated regions that show activations specifically related to the viewing of sexually intense pictures while controlling for general emotional arousal (GEA) or pleasure. Activations in the ventral striatum and hypothalamus were found to be modulated by the stimulus' specific sexual intensity (SSI) while activations in the anterior cingulate cortex were associated with an interaction between sexual intensity and emotional valence. In contrast, activation in other regions like the dorsomedial prefrontal cortex, the mediodorsal thalamus and the amygdala was associated only with a general emotional component during sexual arousal. No differences were found in these effects when comparing females and males. Our findings demonstrate for the first time neural differentiation between emotional and sexual components in the neural network underlying sexual arousal.

  18. [Measurement of cerebral blood flow using phase-contrast MRI].

    Science.gov (United States)

    Obata, T; Shishido, F; Koga, M; Ikehira, H; Kimura, F; Yoshida, K

    1997-07-01

    The development of phase-contrast magnetic resonance imaging(P-C MRI) provides a noninvasive method for measurement of volumetric blood flow(VFR). The VFR of the left and right internal carotid arteries and basilar artery were measured using P-C MRI, and total cerebral blood flow(tCBF) was calculated by summing up the VFR values in three vessels. We investigated the changes in these blood flows as influenced from age, head size, height, weight, body surface area and handedness. Moreover, regional CBF(rCBF) was measured by combining with the single photon emission computed tomography(SPECT) of 123I. The blood flows were 142 +/- 58 mL/ min(mean +/- SD) in the basilar artery, 229 +/- 86 mL/min in the left, 223 +/- 58 mL/min in the right internal carotid artery, and tCBF was 617 +/- 128 mL/min(Ref. Magn Resn Imaging 14:P. 1143, 1996). Significant increases were observed in head-size-related change of VFR in the basilar artery and height-related change of tCBF. The value of rCBF was easily acquired in combination with SPECT. Phase-contrast MRI is useful for a noninvasive and rapid analysis of cerebral VFR and has potential for clinical use.

  19. MRI evaluation and measurement of the normal odontoid peg position

    Energy Technology Data Exchange (ETDEWEB)

    Cronin, C.G. [Department of Radiology, University College Hospital, Galway (Ireland)]. E-mail: carmelcronin2000@hotmail.com; Lohan, D.G. [Department of Radiology, University College Hospital, Galway (Ireland); Ni Mhuircheartigh, J. [Department of Radiology, University College Hospital, Galway (Ireland); Meehan, C.P. [Department of Radiology, University College Hospital, Galway (Ireland); Murphy, J.M. [Department of Radiology, University College Hospital, Galway (Ireland); Roche, C. [Department of Radiology, University College Hospital, Galway (Ireland)

    2007-09-15

    Aim: To measure the normal distances (and range) from the tip of the odontoid peg to the different reference skull baselines (Chamberlain's, McGregor's, and McRae's line) using magnetic resonance imaging (MRI). Materials and methods: We retrospectively evaluated midline sagittal MRI brain images of 200 adults chosen randomly. Patients did not have symptoms or signs suggestive of basilar impression, spinal trauma, vertebral collapse or disease. Using SPSS data analysis program histograms, mean and standard deviation (SD), median and range values were calculated. These findings were then compared with previous plain radiograph measurements. Results: The mean position of the odontoid peg was 1.2 mm (median 1.5 mm, SD 3 mm) below Chamberlain's line; 0.9 mm (median 1.1, SD 3 mm) below McGregor's line; and 4.6 mm (median 4.8, SD 2.6) below McRae's line. Conclusion: Based on the current population, these results provide the mean and range of normal distances from the odontoid peg to the most frequently used skull baselines using MRI.

  20. 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 ...

  1. Classification of normal and pathological aging processes based on brain MRI morphology measures

    Science.gov (United States)

    Perez-Gonzalez, J. L.; Yanez-Suarez, O.; Medina-Bañuelos, V.

    2014-03-01

    Reported studies describing normal and abnormal aging based on anatomical MRI analysis do not consider morphological brain changes, but only volumetric measures to distinguish among these processes. This work presents a classification scheme, based both on size and shape features extracted from brain volumes, to determine different aging stages: healthy control (HC) adults, mild cognitive impairment (MCI), and Alzheimer's disease (AD). Three support vector machines were optimized and validated for the pair-wise separation of these three classes, using selected features from a set of 3D discrete compactness measures and normalized volumes of several global and local anatomical structures. Our analysis show classification rates of up to 98.3% between HC and AD; of 85% between HC and MCI and of 93.3% for MCI and AD separation. These results outperform those reported in the literature and demonstrate the viability of the proposed morphological indexes to classify different aging stages.

  2. Measuring and distinguishing compositional and maturity properties of lunar soils by remote VIS-NIR spectroscopy

    Science.gov (United States)

    Fischer, Erich M.; Pieters, Carle M.

    1993-03-01

    Space weathering on the lunar surface affects the spectra/optical character of an exposed lunar soil in three ways: the reflectance is reduced, absorption band depths are reduced, and a red-sloped continuum is created and increased with exposure. As a result, the spectrum of a lunar soil is dependent upon both the degree of exposure at the lunar surface and the original composition. It is critical to the remote analysis of lunar soils to differentiate between the optical effects of maturity and the effects of composition. In the laboratory, it is possible to determine and consequently distinguish the degree of exposure, or soil maturity, as measured by parameters such as Is/FeO (e.g., 1; mature defined as Is/FeO greater than or equal to 60), and the composition, as measured by various chemical and petrographical techniques. Lunar soils returned by the Apollo missions provide important ground truth for developing methods for remotely measuring the maturity and the concentration of Fe-bearing minerals in lunar soil. The ground truth spectral data analyzed are from the John Adams lunar soil spectra collection. Soils collected from or near highland terrains are emphasized in the discussion. The mineralogical makeup of mare soils results in behavior somewhat different from highland soils.

  3. Distinguishability revisited

    DEFF Research Database (Denmark)

    Garde, Henrik; Knudsen, Kim

    2017-01-01

    The reconstruction problem in electrical impedance tomography is highly ill-posed, and it is often observed numerically that reconstructions have poor resolution far away from the measurement boundary but better resolution near the measurement boundary. The observation can be quantified...... by the concept of distinguishability of inclusions. This paper provides mathematically rigorous results supporting the intuition. Indeed, for a model problem lower and upper bounds on the distinguishability of an inclusion are derived in terms of the boundary data. These bounds depend explicitly on the distance...... of the inclusion to the boundary, i.e. the depth of the inclusion. The results are obtained for disk inclusions in a homogeneous background in the unit disk. The theoretical bounds are veried numerically using a novel, exact characterization of the forward map as a tridiagonal matrix....

  4. Imaging of adult flatfoot: correlation of radiographic measurements with MRI.

    Science.gov (United States)

    Lin, Yu-Ching; Mhuircheartaigh, Jennifer Ni; Lamb, Joshua; Kung, Justin W; Yablon, Corrie M; Wu, Jim S

    2015-02-01

    OBJECTIVE. The purpose of this study is to determine whether radiographic foot measurements can predict injury of the posterior tibial tendon (PTT) and the supporting structures of the medial longitudinal arch as diagnosed on MRI. MATERIALS AND METHODS. After institutional review board approval, 100 consecutive patients with radiographic and MRI examinations performed within a 2-month period were enrolled. Thirty-one patients had PTT dysfunction clinically, and 69 patients had other causes of ankle pain. Talonavicular uncoverage angle, incongruency angle, calcaneal pitch angle, Meary angle, cuneiform-to-fifth metatarsal height, and talar tilt were calculated on standing foot or ankle radiographs. MRI was used to assess for abnormalities of the PTT (tenosynovitis, tendinosis, and tear) and supporting structures of the medial longitudinal arch (spring ligament, deltoid ligament, and sinus tarsi). Statistical analysis was performed using the chi-square and Fisher exact tests for categoric variables; the Student t test was used for continuous variables. RESULTS. There was a statistically significant association of PTT tear with abnormal talonavicular uncoverage angle, calcaneal pitch angle, Meary angle, and cuneiform-to-fifth metatarsal height. PTT tendinosis and isolated tenosynovitis had a poor association with most radiologic measurements. If both calcaneal pitch and Meary angles were normal, no PTT tear was present. An abnormal calcaneal pitch angle had the best association with injury to the supporting medial longitudinal arch structures. CONCLUSION. Radiographic measurements, especially calcaneal pitch and Meary angles, can be useful in detecting PTT tears. Calcaneal pitch angle provides the best assessment of injury to the supporting structures of the medial longitudinal arch.

  5. Analysis of the utility of diffusion-weighted MRI and apparent diffusion coefficient values in distinguishing central nervous system toxoplasmosis from lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Paul C.; Donovan Post, M. Judith; Bruce-Gregorios, Jocelyn [University of Miami, Jackson Memorial Hospital, Miami, FL (United States); Oschatz, Elizabeth; Stadler, Alfred; Thurnher, Majda M. [Medical University of Vienna, Department of Radiology Neuroradiology Section, Vienna (Austria)

    2006-10-15

    Toxoplasmosis and lymphoma are common lesions of the central nervous system in patients with AIDS. It is often difficult to distinguish between these lesions both clinically and radiographically. Previous research has demonstrated restricted diffusion within cerebral lymphomas and bacterial abscesses. However, little work has been done to evaluate the diffusion characteristics of toxoplasmosis lesions. This study was designed to explore further the utility of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps and values in making the distinction between toxoplasmosis and lymphoma. The magnetic resonance imaging (MRI) studies of 36 patients, including 22 with toxoplasmosis (all of whom had AIDS) and 14 with lymphoma (8 of whom had AIDS), at two institutions were reviewed retrospectively. The characteristics of the lesions on DWI were evaluated, and the ADC ratios of the lesions were calculated and compared. There was significant overlap of the ADC ratios of toxoplasma and lymphoma, most notably in the intermediate (1.0-1.6) range. There was variability in ADC ratios even among different lesions in the same patient. In only a minority of the lymphoma patients were the ADC ratios low enough to suggest the correct diagnosis. Our study showed that toxoplasmosis exhibits a wide spectrum of diffusion characteristics with ADC ratios which have significant overlap with those of lymphoma. Therefore, in the majority of patients, ADC ratios are not definitive in making the distinction between toxoplasmosis and lymphoma. (orig.)

  6. Carpal angles as measured on CT and MRI: can we simply translate radiographic measurements?

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Stephanie; Ghumman, Simranjit S.; Moser, Thomas P. [Hopital Notre-Dame (CHUM), Department of Radiology, Centre Hospitalier de l' Universite de Montreal, Montreal, QC (Canada); Ladouceur, Martin [Research Center CHUM, Montreal, QC (Canada)

    2014-12-15

    To determine the reliability of carpal angles measured on CT and MRI compared to radiography and assess if these measurements are interchangeable. Our institutional ethic research committee approved this study. For this retrospective study, two independent observers measured the scapholunate (SL), capitolunate (CL), radiolunate (RL), and radioscaphoid (RS) angles on 21 sets of exams, with each set including a radiograph, CT, and MRI of the same wrist. Inter- and intra-observer agreements were evaluated with the intraclass correlation coefficient (ICC). Linear mixed models and two-way contingency tables were used to determine if the angles measured on cross-sectional modalities were significantly different from those obtained on radiography. Inter-observer agreement was strong (ICC >0.8) for all angles, except for the RL angle measured on MRI (ICC 0.68). Intra-observer agreement was also strong for all angles, except for the CL angle measured on CT (ICC 0.66). SL angles measured on CT and MRI were not statistically different from those measured on radiographs (p = 0.37 and 0.36, respectively), unlike CL, RL, and RS angles (p < 0.05). Accuracy between modalities varied between 76 and 86 % for the SL angle and ranged between 43 and 76 % for the other angles. CL, RL, and RS angles showed large intermodality variability. Therefore, their measurements on CT or MRI could potentially lead to miscategorization. Conversely, our data showing no significant difference between modalities, SL angle could be measured on CT and MRI to assess wrist instability with a lower risk of error. (orig.)

  7. Noninvasive measurement of conductivity anisotropy at larmor frequency using MRI.

    Science.gov (United States)

    Lee, Joonsung; Song, Yizhuang; Choi, Narae; Cho, Sungmin; Seo, Jin Keun; Kim, Dong-Hyun

    2013-01-01

    Anisotropic electrical properties can be found in biological tissues such as muscles and nerves. Conductivity tensor is a simplified model to express the effective electrical anisotropic information and depends on the imaging resolution. The determination of the conductivity tensor should be based on Ohm's law. In other words, the measurement of partial information of current density and the electric fields should be made. Since the direct measurements of the electric field and the current density are difficult, we use MRI to measure their partial information such as B1 map; it measures circulating current density and circulating electric field. In this work, the ratio of the two circulating fields, termed circulating admittivity, is proposed as measures of the conductivity anisotropy at Larmor frequency. Given eigenvectors of the conductivity tensor, quantitative measurement of the eigenvalues can be achieved from circulating admittivity for special tissue models. Without eigenvectors, qualitative information of anisotropy still can be acquired from circulating admittivity. The limitation of the circulating admittivity is that at least two components of the magnetic fields should be measured to capture anisotropic information.

  8. MRI as outcome measure in facioscapulohumeral muscular dystrophy

    DEFF Research Database (Denmark)

    Andersen, Grete; Dahlqvist, Julia R; Vissing, Christoffer R

    2017-01-01

    muscles. Changes were compared with those in FSHD score, muscle strength (hand-held dynamometry), 6-minute-walk-distance, 14-step-stair-test, and 5-time-sit-to-stand-test. Composite absolute fat fraction of all assessed muscles increased by 0.036 (CI 0.026-0.046, P increases in all measured...... disease progression in patients with FSHD1. Ambulatory patients with confirmed diagnosis of FSHD1 (25/20 men/women, age 20-75 years, FSHD score: 0-12) were tested with 359-560-day interval between tests. Using the MRI Dixon technique, muscle fat replacement was evaluated in paraspinal, thigh, and calf...... muscle groups. The clinical severity FSHD score worsened (10%, P muscle strength decreased over the hip (8%), neck (8%), and back (17%) (P muscle strength...

  9. Measuring Memory Reactivation With Functional MRI: Implications for Psychological Theory.

    Science.gov (United States)

    Levy, Benjamin J; Wagner, Anthony D

    2013-01-01

    Environmental cues often remind us of earlier experiences by triggering the reactivation of memories of events past. Recent evidence suggests that memory reactivation can be observed using functional MRI and that distributed pattern analyses can even provide evidence of reactivation on individual trials. The ability to measure memory reactivation offers unique and powerful leverage on theoretical issues of long-standing interest in cognitive psychology, providing a means to address questions that have proven difficult to answer with behavioral data alone. In this article, we consider three instances. First, reactivation measures can indicate whether memory-based inferences (i.e., generalization) arise through the encoding of integrated cross-event representations or through the flexible expression of separable event memories. Second, online measures of memory reactivation may inform theories of forgetting by providing information about when competing memories are reactivated during competitive retrieval situations. Finally, neural reactivation may provide a window onto the role of replay in memory consolidation. The ability to track memory reactivation, including at the individual trial level, provides unique leverage that is not afforded by behavioral measures and thus promises to shed light on such varied topics as generalization, integration, forgetting, and consolidation.

  10. Relationship of patient-reported outcomes with MRI measures in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Baker, Joshua F; Conaghan, Philip G; Emery, Paul;

    2017-01-01

    PURPOSE: We assessed whether MRI measures of synovitis, osteitis and bone erosion were associated with patient-reported outcomes (PROs) in a longitudinal clinical trial setting among patients with rheumatoid arthritis (RA). METHODS: This longitudinal cohort of 291 patients with RA was derived from...... across treatment groups. CONCLUSIONS: MRI measures of inflammation and structural damage correlate independently with physical function, pain and patient global assessments. These observations support the validity of MRI biomarkers. TRIAL REGISTRATION NUMBER: NCT00264537; Post-results....

  11. Interfacial tension measurements using MRI drop shape analysis.

    Science.gov (United States)

    Hussain, R; Vogt, S J; Honari, A; Hollingsworth, K G; Sederman, A J; Mitchell, J; Johns, M L

    2014-02-18

    Accurate interfacial tension data for fluid systems such as hydrocarbons and water is essential to many applications such as reservoir oil and gas recovery predictions. Conventional interfacial tension measurement techniques typically use optical images to analyze droplet shapes but require that the continuous-phase fluid be optically transparent and that the fluids are not refractive index matched. Magnetic resonance images obtain contrast between fluids using other mechanisms such as magnetic relaxation weighting, so systems that are impossible to measure with optical methods may be analyzed. In this article, we present high-field (9.4 T) MRI images of various droplets analyzed with axisymmetric drop shape analysis. The resultant interfacial tension data show good agreement with literature data. The method is subsequently demonstrated using both opaque continuous phases and refractive-index-matched fluids. We conclude with a brief consideration of the potential to extrapolate the methodology to lower magnetic fields (0.3 T), featuring more accessible hardware; although droplet imaging is possible, resolution and stability do not currently permit accurate interfacial tension measurements.

  12. Surface EMG measurements during fMRI at 3T : Accurate EMG recordings after artifact correction

    NARCIS (Netherlands)

    van Duinen, Hiske; Zijdewind, Inge; Hoogduin, H; Maurits, N

    2005-01-01

    In this experiment, we have measured surface EMG of the first dorsal interosseus during predefined submaximal isometric contractions (5, 15, 30, 50, and 70% of maximal force) of the index finger simultaneously with fMRI measurements. Since we have used sparse sampling fMRI (3-s scanning; 2-s non-sca

  13. Measuring myocardial perfusion: the role of PET, MRI and CT.

    Science.gov (United States)

    Qayyum, A A; Kastrup, J

    2015-06-01

    Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion. Myocardial perfusion abnormalities are the first sign of the ischaemic cascade in the development of coronary artery disease (CAD). PET is considered the non-invasive clinical reference standard for absolute quantification of myocardial perfusion. The diagnostic and prognostic value of PET is well-known and is used in routine clinical practice. However, PET uses radioactive tracers and has a lower spatial resolution compared to CMR and CT. CMR and CT are emerging techniques in the field of myocardial perfusion imaging. CMR uses magnetic resonance to obtain images, whereas CT uses x-rays during first-pass of non-ionic and ionic contrast agents, respectively. Absolute quantification with CMR has yet to be established in routine clinical practice, while CT has yet to prove its diagnostic and prognostic value. The upcoming years may change the way we diagnose and treat patients suspected of having CAD with more precise methods for measuring myocardial perfusion. The aim of this comprehensive review is to discuss current and emerging imaging techniques used for myocardial perfusion imaging.

  14. 3D reconstruction, visualization, and measurement of MRI images

    Science.gov (United States)

    Pandya, Abhijit S.; Patel, Pritesh P.; Desai, Mehul B.; Desai, Paramtap

    1999-03-01

    This paper primarily focuses on manipulating 2D medical image data that often come in as Magnetic Resonance and reconstruct them into 3D volumetric images. Clinical diagnosis and therapy planning using 2D medical images can become a torturous problem for a physician. For example, our 2D breast images of a patient mimic a breast carcinoma. In reality, the patient has 'fat necrosis', a benign breast lump. Physicians need powerful, accurate and interactive 3D visualization systems to extract anatomical details and examine the root cause of the problem. Our proposal overcomes the above mentioned limitations through the development of volume rendering algorithms and extensive use of parallel, distributed and neural networks computing strategies. MRI coupled with 3D imaging provides a reliable method for quantifying 'fat necrosis' characteristics and progression. Our 3D interactive application enables a physician to compute spatial measurements and quantitative evaluations and, from a general point of view, use all 3D interactive tools that can help to plan a complex surgical operation. The capability of our medical imaging application can be extended to reconstruct and visualize 3D volumetric brain images. Our application promises to be an important tool in neurological surgery planning, time and cost reduction.

  15. On the feasibility of concurrent human TMS-EEG-fMRI measurements.

    Science.gov (United States)

    Peters, Judith C; Reithler, Joel; Schuhmann, Teresa; de Graaf, Tom; Uludag, Kâmil; Goebel, Rainer; Sack, Alexander T

    2013-02-01

    Simultaneously combining the complementary assets of EEG, functional MRI (fMRI), and transcranial magnetic stimulation (TMS) within one experimental session provides synergetic results, offering insights into brain function that go beyond the scope of each method when used in isolation. The steady increase of concurrent EEG-fMRI, TMS-EEG, and TMS-fMRI studies further underlines the added value of such multimodal imaging approaches. Whereas concurrent EEG-fMRI enables monitoring of brain-wide network dynamics with high temporal and spatial resolution, the combination with TMS provides insights in causal interactions within these networks. Thus the simultaneous use of all three methods would allow studying fast, spatially accurate, and distributed causal interactions in the perturbed system and its functional relevance for intact behavior. Concurrent EEG-fMRI, TMS-EEG, and TMS-fMRI experiments are already technically challenging, and the three-way combination of TMS-EEG-fMRI might yield additional difficulties in terms of hardware strain or signal quality. The present study explored the feasibility of concurrent TMS-EEG-fMRI studies by performing safety and quality assurance tests based on phantom and human data combining existing commercially available hardware. Results revealed that combined TMS-EEG-fMRI measurements were technically feasible, safe in terms of induced temperature changes, allowed functional MRI acquisition with comparable image quality as during concurrent EEG-fMRI or TMS-fMRI, and provided artifact-free EEG before and from 300 ms after TMS pulse application. Based on these empirical findings, we discuss the conceptual benefits of this novel complementary approach to investigate the working human brain and list a number of precautions and caveats to be heeded when setting up such multimodal imaging facilities with current hardware.

  16. [Techniques for measuring phakic and pseudophakic accommodation. Methodology for distinguishing between neurological and mechanical accommodative insufficiency].

    Science.gov (United States)

    Roche, O; Roumes, C; Parsa, C

    2007-11-01

    The methods available for studying accommodation are evaluated: Donder's "push-up" method, dynamic retinoscopy, infrared optometry using the Scheiner principle, and wavefront analysis are each discussed with their inherent advantages and limitations. Based on the methodology described, one can also distinguish between causes of accommodative insufficiency. Dioptric insufficiency (accommodative lag) that remains equal at various testing distances from the subject indicates a sensory/neurologic (afferent), defect, whereas accommodative insufficiency changing with distance indicates a mechanical/restrictive (efferent) defect, such as in presbyopia. Determining accommodative insufficiency and the cause can be particularly useful when examining patients with a variety of diseases associated with reduced accommodative ability (e.g., Down syndrome and cerebral palsy) as well as in evaluating the effectiveness of various potentially accommodating intraocular lens designs.

  17. Accuracy of MRI technique in measuring tendon cross-sectional area

    DEFF Research Database (Denmark)

    Couppé, Christian; Svensson, R. B.; Elbrønd (Bibs), Vibeke Sødring

    2014-01-01

    Magnetic resonance imaging (MRI) has commonly been applied to determine tendon cross-sectional area (CSA) and length either to measure structural changes or to normalize mechanical measurements to stress and strain. The ability to reproduce CSA measurements on MRI images has been reported......, but the accuracy in relation to actual tendon dimensions has never been investigated. The purpose of this study was to compare tendon CSA measured by MRI with that measured in vitro with the mould casting technique. The knee of a horse was MRI-scanned with 1.5 and 3 tesla, and two examiners measured the patellar...... tendon CSA. Thereafter, the patellar tendon of the horse was completely dissected and embedded in an alginate cast. The CSA of the embedded tendon was measured directly by optical imaging of the cast impression. 1.5 tesla grey tendon CSA and 3 tesla grey tendon CSA were 16.5% and 13.2% lower than...

  18. Estimation of intersubject variability of cerebral blood flow measurements using MRI and positron emission tomography

    DEFF Research Database (Denmark)

    Henriksen, Otto Mølby; Larsson, Henrik B W; Hansen, Adam E;

    2012-01-01

    PURPOSE: To investigate the within and between subject variability of quantitative cerebral blood flow (CBF) measurements in normal subjects using various MRI techniques and positron emission tomography (PET). MATERIALS AND METHODS: Repeated CBF measurements were performed in 17 healthy, young...... subjects using three different MRI techniques: arterial spin labeling (ASL), dynamic contrast enhanced T1 weighted perfusion MRI (DCE) and phase contrast mapping (PCM). All MRI measurements were performed within the same session. In 10 of the subjects repeated CBF measurements by (15) O labeled water PET......L/100 g/min, 16.2% and 4.8%, for DCE 43.0 mL/100 g/min, 20.0%, 15.1% and for PET 41.9 mL/100 g/min, 16.5% and 11.9%, respectively. Only for DCE and PCM a significant positive correlation between measurements was demonstrated. CONCLUSION: These findings confirm large between subject variability in CBF...

  19. Measuring competition in plant communities where it is difficult to distinguish individual plants

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2011-01-01

    . The method allows direct measurements of the competitive effects of neighbouringzplants on plant performance and the estimation of parameters that describe the ecological processes of plantplant interactions during the growing season as well as the process of survival and recruitment between growing seasons...... measured by plant cover and vertical density (a measure that is correlated to the 3-dimensional space occupancy and biomass). Both plant cover and vertical density are measured in a standard pin-point analysis in the beginning and at the end of the growing season. In the outlined competition model....... Additionally, the presented method is suited for testing different ecological hypothesis on competitive interactions along environmental gradients, investigating the importance of competition, as well as predicting the likelihood of different ecological scenarios....

  20. Physiological measurements using ultra-high field fMRI: a review.

    Science.gov (United States)

    Francis, Sue; Panchuelo, Rosa Sanchez

    2014-09-01

    Functional MRI (fMRI) has grown to be the neuroimaging technique of choice for investigating brain function. This topical review provides an outline of fMRI methods and applications, with a particular emphasis on the recent advances provided by ultra-high field (UHF) scanners to allow functional mapping with greater sensitivity and improved spatial specificity. A short outline of the origin of the blood oxygenation level dependent (BOLD) contrast is provided, followed by a review of BOLD fMRI methods based on gradient-echo (GE) and spin-echo (SE) contrast. Phase based fMRI measures, as well as perfusion contrast obtained with the technique of arterial spin labelling (ASL), are also discussed. An overview of 7 T based functional neuroimaging is provided, outlining the potential advances to be made and technical challenges to be addressed.

  1. Cerebral Blood Flow Measured by Arterial Spin Labeling MRI as a Preclinical Marker of Alzheimer’s Disease

    Science.gov (United States)

    Wierenga, Christina E.; Hays, Chelsea C.; Zlatar, Zvinka Z.

    2017-01-01

    There is growing recognition that cerebral hypoperfusion is related to the pathogenesis of Alzheimer’s disease (AD), implicating the measurement of cerebral blood flow (CBF) as a possible biomarker of AD. The ability to identify the earliest and most reliable markers of incipient cognitive decline and clinical symptoms is critical to develop effective preventive strategies and interventions for AD. Arterial spin labeling (ASL) magnetic resonance imaging (MRI) measures CBF by magnetically labeling arterial water and using it as an endogenous tracer. Studies using ASL MRI in humans indicate that CBF changes are present several years before the development of the clinical symptoms of AD. Moreover, ASL-measured CBF has been shown to distinguish between cognitively normal individuals, adults at risk for AD, and persons diagnosed with AD. Some studies indicate that CBF may even be sensitive for predicting cognitive decline and conversion to mild cognitive impairment and AD over time. Taken together, evidence suggests that the current staging models of AD biomarker pathology should incorporate early changes in CBF as a useful biomarker, possibly present even earlier than amyloid β accumulation. Though still a research tool, ASL imaging is a promising non-invasive and reliable method with the potential to serve as a future clinical tool for the measurement of CBF in preclinical AD. PMID:25159672

  2. For Distinguishing Conjugate Hidden Subgroups, the Pretty Good Measurement is as Good as it Gets

    CERN Document Server

    Moore, Cristopher; Moore, Cristopher; Russell, Alexander

    2005-01-01

    Recently Bacon, Childs and van Dam showed that the ``pretty good measurement'' (PGM) is optimal for the Hidden Subgroup Problem on the dihedral group D_n in the case where the hidden subgroup is chosen uniformly from the n involutions. We show that, for any group and any subgroup H, the PGM is the optimal one-register experiment in the case where the hidden subgroup is a uniformly random conjugate of H. We go on to show that when H forms a Gel'fand pair with its parent group, the PGM is the optimal measurement for any number of registers. In both cases we bound the probability that the optimal measurement succeeds. This generalizes the case of the dihedral group, and includes a number of other examples of interest.

  3. Early development of arterial spin labeling to measure regional brain blood flow by MRI.

    Science.gov (United States)

    Koretsky, Alan P

    2012-08-15

    Two major avenues of work converged in the late 1980's and early 1990's to give rise to brain perfusion MRI. The development of anatomical brain MRI quickly had as a major goal the generation of angiograms using tricks to label flowing blood in macroscopic vessels. These ideas were aimed at getting information about microcirculatory flow as well. Over the same time course the development of in vivo magnetic resonance spectroscopy had as its primary goal the assessment of tissue function and in particular, tissue energetics. For this the measurement of the delivery of water to tissue was critical for assessing tissue oxygenation and viability. The measurement of the washin/washout of "freely" diffusible tracers by spectroscopic based techniques pointed the way for quantitative approaches to measure regional blood flow by MRI. These two avenues came together in the development of arterial spin labeling (ASL) MRI techniques to measure regional cerebral blood flow. The early use of ASL to measure brain activation to help verify BOLD fMRI led to a rapid development of ASL based perfusion MRI. Today development and applications of regional brain blood flow measurements with ASL continues to be a major area of activity.

  4. Distinguishing Differential Testlet Functioning from Differential Bundle Functioning Using the Multilevel Measurement Model

    Science.gov (United States)

    Beretvas, S. Natasha; Walker, Cindy M.

    2012-01-01

    This study extends the multilevel measurement model to handle testlet-based dependencies. A flexible two-level testlet response model (the MMMT-2 model) for dichotomous items is introduced that permits assessment of differential testlet functioning (DTLF). A distinction is made between this study's conceptualization of DTLF and that of…

  5. Preliminary evaluation of MRI-derived input function for quantitative measurement of glucose metabolism in an integrated PET-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Anazodo, Udunna; Kewin, Matthew [Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario (Canada); Finger, Elizabeth [Department of Clinical Neurological Sciences, Western University, London, Ontario (Canada); Thiessen, Jonathan; Hadway, Jennifer; Butler, John [Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario (Canada); Pavlosky, William [Diagnostic Imaging, St Joseph' s Health Care, London, Ontario (Canada); Prato, Frank; Thompson, Terry; St Lawrence, Keith [Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario (Canada)

    2015-05-18

    PET semi-quantitative methods such as relative uptake value can be robust but offer no biological information and do not account for intra-subject variability in tracer administration or clearance. Simultaneous multimodal measurements that combine PET and MRI not only permit crucial multiparametric measurements, it provides means of applying tracer kinetic modelling without the need for serial arterial blood sampling. In this study we adapted an image-derived input function (IDIF) method to improve characterization of glucose metabolism in an ongoing dementia study. Here we present preliminary results in a small group of frontotemporal dementia patients and controls. IDIF was obtained directly from dynamic PET data guided by regions of interest drawn on carotid vessels on high resolution T1-weighted MR Images. IDIF was corrected for contamination of non-arterial voxels. A validation of the method was performed in a porcine model in a PET-CT scanner comparing IDIF to direct arterial blood samples. Metabolic rate of glucose (CMRglc) was measured voxel-by-voxel in gray matter producing maps that were compared between groups. Net influx rate (Ki) and global mean CMRglc are reported. A good correlation (r = 0.9 p<0.0001) was found between corrected IDIF and input function measured from direct arterial blood sampling in the validation study. In 3 FTD and 3 controls, a trend towards hypometabolism was found in frontal, temporal and parietal lobes similar to significant differences previously reported by other groups. The global mean CMRglc and Ki observed in control subjects are in line with previous reports. In general, kinetic modelling of PET-FDG using an MR-IDIF can improve characterization of glucose metabolism in dementia. This method is feasible in multimodal studies that aim to combine PET molecular imaging with MRI as dynamic PET can be acquired along with multiple MRI measurements.

  6. Which factors influence MRI-pathology concordance of tumour size measurements in breast cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, M.; Frauenfelder, T. [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Berg, D. [Urbankrankenhaus Berlin, Anesthesiology, Berlin (Germany); Ramaswamy, A. [University Hospital Marburg, Pathology, Marburg (Germany); Timmesfeld, N. [Philipps University Marburg, Institute for Medical Biometry and Epidemiology, Marburg (Germany)

    2016-05-15

    To assess MRI-pathology concordance and factors influencing tumour size measurement in breast cancer. MRI tumour size (greatest diameter in anatomical planes (MRI-In-Plane) and greatest diameter along main tumour axis (MRI-MPR)) of 115 consecutive breast lesions (59 invasive lobular carcinoma, 46 invasive ductal carcinoma, and 10 ductal carcinoma in situ) was retrospectively compared to size measured at histopathology (pT size (Path-TNM) and greatest tumour diameter as relevant for excision (Path-Diameter; reference standard)). Histopathological tumour types, preoperative palpability, surgical management, additional high-risk lesions, and BI-RADS lesion type (mass versus non-mass enhancements) were assessed as possible influencing factors. Systematic errors were most pronounced between MRI-MPR and Path-TNM (7.1 mm, limits of agreement (LoA) [-21.7; 35.9]), and were lowest between MRI-In-Plane and Path-Diameter (0.2 mm, LoA [-19.7; 20.1]). Concordance rate of MRI-In-Plane with Path-Diameter was 86 % (97/113), overestimation 9 % (10/113) and underestimation 5 % (6/113); BI-RADS mass lesions were overestimated in 7 % (6/81) versus 41 % (13/32) for non-mass enhancements. On multivariate analysis only BI-RADS lesion type significantly influenced MRI-pathology concordance (p < 0.001). 2/59 (3 %) ILC did not enhance. Concordance rate varies according to the execution of MRI and histopathological measurements. Beyond this only non-mass enhancement significantly predicted discordance. (orig.)

  7. Distinguishing phosphate from fertilizers and wastewater treatment plant effluents in Western Canada using oxygen isotope measurements

    Science.gov (United States)

    Fau, Veronique; Nightingale, Michael; Tamburini, Frederica; Mayer, Bernhard

    2014-05-01

    The successful application of oxygen isotope ratios as a tracer for phosphate in aquatic ecosystems requires that different sources of phosphate are isotopically distinct. The objective of this study was to determine whether the oxygen isotope ratios of phosphate from fertilizers and effluents from wastewater treatment plants in Western Canada are isotopically distinct. Therefore, we carried out oxygen isotope analyses on phosphate in effluent from five different wastewater treatment plants (WWTP) in the Bow River watershed of Alberta, Canada. Samples were collected directly from the final effluent (post-UV) in Banff and Canmore upstream of Calgary, and from effluents of Calgary's WWTPs at Bonnybrook, Fish Creek and Pine Creek. We also carried out oxygen isotope analyses on a variety of phosphate-containing fertilizers that are widely used in Western Canada. Historically, most of the phosphate contained in manufactured fertilizers sold in Alberta came from two distinct deposits: 1) a weathered Pliocene igneous carbonatite located in eastern Canada, and 2) the Permian Phosphoria Formation in the western USA. Phosphate (PO43-) contained in the water or the fertilizer was concentrated and quantitatively converted to pure silver phosphate (Ag3PO4). The silver phosphate was then reduced with carbon in an oxygen free environment using a TC/EA pyrolysis reactor linked to a mass spectrometer where 18O/16O ratios of CO were measured in continuous flow mode. Preparation of samples for δ18OPO4 analyses was conducted using the Magnesium Induced Coprecipitation (MAGIC) method. Expected oxygen isotope ratios for phosphate in equilibrium with water (δ18Oeq) were calculated using the Longinelli and Nuti equation: T (° C) = 111.4 - 4.3 (δ18Oeq - δ18Owater). Measured δ18O values of phosphate for fertilizer samples varied from 8 to 25 oÈ®n average, fertilizer samples of sedimentary origin had higher δ18O values (15.8) than those of igneous origin (11.5). Phosphate isotopic

  8. Sensitivity and specificity of different measures of adiposity to distinguish between low/high motor coordination

    Directory of Open Access Journals (Sweden)

    Luís Lopes

    2015-02-01

    Full Text Available OBJECTIVE: This study aimed to determine the ability of different measures of adiposity to discriminate between low/high motor coordination and to evaluate the relationship between different measures of adiposity and motor coordination. METHODS: This study included 596 elementary school children aged 9 to 12 years (218 females - 47.1%. Weight, height, and waist circumference were objectively measured by standardized protocols. Body fat percentage was estimated by bioelectric impedance. Body mass index and waist-to-height ratio were computed. Motor coordination was assessed by the Körperkoordination Test für Kinder. Cardiorespiratory fitness was predicted by a maximal multistage 20 m shuttle-run test of the Fitnessgram Test Battery. A questionnaire was used to assess the maternal educational level. RESULTS: The receiver operating characteristic performance of body fat percentage in females and waist circumference in males presented a slightly better discriminatory accuracy than body mass index, waist circumference and waist-to-height ratio in predicting low motor coordination. After adjustments, logistic regression analyses showed that body mass index (ß = 2.155; 95% CI: 1.164-3.992; p = 0.015 for girls; ß = 3.255; 95% CI: 1.740-6.088; p < 0.001 for males, waist circumference (ß = 2.489; 95% CI: 1.242-4.988; p = 0.010 for girls; ß = 3.296; 95% CI: 1.784-6.090; p < 0.001 for males, body fat percentage (ß = 2.395; 95% CI: 1.234-4.646; p = 0.010 for girls; ß = 2.603; 95% CI: 1.462-4.634; p < 0.001 for males and waist-to-height ratio (ß = 3.840; 95% CI: 2.025-7.283; p < 0.001 for males were positively and significantly associated with motor coordination in both sexes, with the exception of waist-to-height ratio in girls (ß = 1.343; 95% CI: 0.713-2.528; p = 0.381. CONCLUSION: Body fat percentage and waist circumference showed a slightly better discriminatory accuracy in predicting low motor coordination for females and for males

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  11. The Australian MRI-Linac Program: measuring profiles and PDD in a horizontal beam

    Science.gov (United States)

    Begg, J.; George, A.; Alnaghy, S. J.; Causer, T.; Alharthi, T.; Glaubes, L.; Dong, B.; Goozee, G.; Liney, G.; Holloway, L.; Keall, P.

    2017-02-01

    The Australian MRI-Linac consists of a fixed horizontal photon beam combined with a MRI. Commissioning required PDD and profiles measured in a horizontal set-up using a combination of water tank measurements and gafchromic film. To validate the methodology, measurements were performed comparing PDD and profiles measured with the gantry angle set to 0 and 90° on a conventional linac. Results showed agreement to within 2.0% for PDD measured using both film and the water tank at gantry 90° relative to PDD acquired using gantry 0°. Profiles acquired using a water tank at both gantry 0 and 90° showed agreement in FWHM to within 1 mm. The agreement for both PDD and profiles measured at gantry 90° relative to gantry 0° curves indicates that the methodology described can be used to acquire the necessary beam data for horizontal beam lines and in particular, commissioning the Australian MRI-linac.

  12. Measurement of Liver Iron Concentration by MRI Is Reproducible

    Directory of Open Access Journals (Sweden)

    José María Alústiza

    2015-01-01

    Full Text Available Purpose. The objectives were (i construction of a phantom to reproduce the behavior of iron overload in the liver by MRI and (ii assessment of the variability of a previously validated method to quantify liver iron concentration between different MRI devices using the phantom and patients. Materials and Methods. A phantom reproducing the liver/muscle ratios of two patients with intermediate and high iron overload. Nine patients with different levels of iron overload were studied in 4 multivendor devices and 8 of them were studied twice in the machine where the model was developed. The phantom was analysed in the same equipment and 14 times in the reference machine. Results. FeCl3 solutions containing 0.3, 0.5, 0.6, and 1.2 mg Fe/mL were chosen to generate the phantom. The average of the intramachine variability for patients was 10% and for the intermachines 8%. For the phantom the intramachine coefficient of variation was always below 0.1 and the average of intermachine variability was 10% for moderate and 5% for high iron overload. Conclusion. The phantom reproduces the behavior of patients with moderate or high iron overload. The proposed method of calculating liver iron concentration is reproducible in several different 1.5 T systems.

  13. Selecting magnetic resonance imaging (MRI) outcome measures for juvenile idiopathic arthritis (JIA) clinical trials: first report of the MRI in JIA special interest group.

    Science.gov (United States)

    Hemke, Robert; Doria, Andrea S; Tzaribachev, Nikolay; Maas, Mario; van der Heijde, Désirée M F M; van Rossum, Marion A J

    2014-02-01

    Recent advances in magnetic resonance imaging (MRI) techniques have substantially improved the evaluation of joint pathologies in juvenile idiopathic arthritis (JIA). Because of the current availability of highly effective antirheumatic therapies and the unique and useful features of MRI, there is a growing need for an accurate and reproducible MRI assessment scoring system for JIA, such as the rheumatoid arthritis MRI Scoring (RAMRIS) for patients with rheumatoid arthritis (RA). To effectively evaluate the efficacy of treatment in clinical research trials, we need to develop and validate scoring methods to accurately measure joint outcomes, standardize imaging protocols for data acquisition and interpretation, and create imaging atlases to differentiate physiologic and pathologic joint findings in childhood and adolescence. Such a standardized, validated, JIA-MRI scoring method could be used as an outcome measure in clinical trials.

  14. Ultrasonographic measurement of the ligamentum flavum depth; is it a reliable method to distinguish true and false loss of resistance?

    Science.gov (United States)

    Pak, Michael Haejin; Lee, Won Hyung; Ko, Young Kwon; So, Sang Young; Kim, Hyun Joong

    2012-04-01

    Previous studies have shown that if performed without radiographic guidance, the loss of resistance (LOR) technique can result in inaccurate needle placement in up to 30% of lumbar epidural blocks. To date, no study has shown the efficacy of measuring the depth of the posterior complex (ligamentum flavum, epidural space, and posterior dura) ultrasonographically to distinguish true and false LOR. 40 cervical epidural blocks were performed using the LOR technique and confirmed by epidurograms. Transverse ultrasound images of the C6/7 area were taken before each cervical epidural block, and the distances from the skin to the posterior complex, transverse process, and supraspinous ligament were measured on each ultrasound view. The number of LOR attempts was counted, and the depth of each LOR was measured with a standard ruler. Correlation of false and true positive LOR depth with ultrasonographically measured depth was also statistically analyzed. 76.5% of all cases (26 out of 34) showed false positive LOR. Concordance correlation coefficients between the measured distances on ultrasound (skin to ligamentum flavum) and actual needle depth were 0.8285 on true LOR. Depth of the true positive LOR correlated with height and weight, with a mean of 5.64 ± 1.06 cm, while the mean depth of the false positive LOR was 4.08 ± 1.00 cm. Ultrasonographic measurement of the ligamentum flavum depth (or posterior complex) preceding cervical epidural block is beneficial in excluding false LOR and increasing success rates of cervical epidural blocks.

  15. [Pulmonary blood flow measurement using magnetic resonance imaging (MRI) without contrast medium;comparison of phase contrast MRI and perfusion-ventilation scintigraphy].

    Science.gov (United States)

    Yatsuyanagi, Eiji; Sato, Kazuhiro; Kikuchi, Keisuke; Saito, Hirotsugu

    2014-02-01

    To define the accuracy of pulmonary arterial blood flow (PA-flow) measured by phase contrast magnetic resonance imaging (PC-MRI), we compared the PA-flow data of PC-MRI with the data of perfusion-ventilation lung scintigraphy. Eighteen patients who preoperatively underwent PA-flow measurement using PC-MRI and perfusion-ventilation lung scintigraphy were evaluated. The PA-flow (cm3/sec) of MRI was calculated by multiplying maximum velocity (cm/sec) by region of interest (ROI) area (cm2) of measured main pulmonary artery using phase contrast method. The left to right ratio (R/L ratio) of PA-flow measured by PC-MRI was compared with the R/L ratios of the date of perfusion-ventilation lung scintigraphy. The R/L ratios of PC-MRI and perfusion lung scintigraphy were 1.43 ± 1.07 and 1.35 ± 0.82, respectively. Both ratios showed excellent correlation( y=-0.50+1.30x, r=0.99,pperfusion lung scintigraphy in the patients with a past history of lung resection, even if their R/L ratios of perfusion lung scintigraphy differed from those of ventilation lung scintigraphy. These results revealed that the PA-flow could be accurately measured by PC-MRI without contrast medium and nuclear medicine instruments.

  16. Comparison of neurite density measured by MRI and histology after TBI.

    Directory of Open Access Journals (Sweden)

    Shiyang Wang

    Full Text Available BACKGROUND: Functional recovery after brain injury in animals is improved by marrow stromal cells (MSC which stimulate neurite reorganization. However, MRI measurement of neurite density changes after injury has not been performed. In this study, we investigate the feasibility of MRI measurement of neurite density in an animal model of traumatic brain injury (TBI with and without MSC treatment. METHODS: Fifteen male Wistar rats, were treated with saline (n = 6 or MSCs (n = 9 and were sacrificed at 6 weeks after controlled cortical impact (CCI. Healthy non-CCI rats (n = 5, were also employed. Ex-vivo MRI scans were performed two days after the rats were sacrificed. Multiple-shell hybrid diffusion imaging encoding scheme and spherical harmonic expansion of a two-compartment water diffusion displacement model were used to extract neurite related parameters. Bielshowski and Luxol Fast blue was used for staining axons and myelin, respectively. Modified Morris water maze and neurological severity score (mNSS test were performed for functional evaluation. The treatment effects, the correlations between neurite densities measured by MRI and histology, and the correlations between MRI and functional variables were calculated by repeated measures analysis of variance, the regression correlation analysis tests, and spearman correlation coefficients. RESULTS: Neurite densities exhibited a significant correlation (R(2>0.80, p<1E-20 between MRI and immuno-histochemistry measurements with 95% lower bound of the intra-correlation coefficient (ICC as 0.86. The conventional fractional anisotropy (FA correlated moderately with histological neurite density (R(2 = 0.59, P<1E-5 with 95% lower bound of ICC as 0.76. MRI data revealed increased neurite reorganization with MSC treatment compared with saline treatment, confirmed by histological data from the same animals. mNSS were significantly correlated with MRI neurite density in the hippocampus region

  17. Efficacy and toxicity in brain tumor treatment - quantitative Measurements using advanced MRI

    DEFF Research Database (Denmark)

    Ravn, Søren

    2016-01-01

    and are now being used for presurgical and radiation therapy (RT) planning. More advanced MRI sequences have gained attention. Sequences such as diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and functional magnetic resonance imaging (fMRI) have entered the clinical world concurrently......From the clinical introduction in the 1980s, MRI has grown to become an indispensable brain imaging modality, mainly due to its excellent ability to visualize soft tissues. Morphologically, T1- and T2-weighted brain tumor MRI have been part of routine diagnostic radiology for more than two decades...... with the introduction of magnets with higher field strength. Ongoing technical development has enabled a change from semiquantitative measurements to a true quantitative approach. This step is expected to have a great impact on the treatment of brain tumor patients in the future. The aim of this Ph.D. dissertation...

  18. Cardiac metabolism measured noninvasively by hyperpolarized 13C MRI

    DEFF Research Database (Denmark)

    Golman, K.; Petersson, J.S.; Magnusson, P.

    2008-01-01

    Pyruvate is included in the energy production of the heart muscle and is metabolized into lactate, alanine, and CO(2) in equilibrium with HCO(3) (-). The aim of this study was to evaluate the feasibility of using (13)C hyperpolarization enhanced MRI to monitor pyruvate metabolism in the heart...... was almost absent (0.2-11%) and the alanine signal was reduced (27-51%). Due to image-folding artifacts the data obtained for lactate were inconclusive. These studies demonstrate that cardiac metabolic imaging with hyperpolarized 1-(13)C-pyruvate is feasible. The changes in concentrations of the metabolites...... within a minute after injection can be detected and metabolic maps constructed Udgivelsesdato: 2008/5...

  19. Determination of Sample Entropy and Fuzzy Measure Entropy Parameters for Distinguishing Congestive Heart Failure from Normal Sinus Rhythm Subjects

    Directory of Open Access Journals (Sweden)

    Lina Zhao

    2015-09-01

    Full Text Available Entropy provides a valuable tool for quantifying the regularity of physiological time series and provides important insights for understanding the underlying mechanisms of the cardiovascular system. Before any entropy calculation, certain common parameters need to be initialized: embedding dimension m, tolerance threshold r and time series length N. However, no specific guideline exists on how to determine the appropriate parameter values for distinguishing congestive heart failure (CHF from normal sinus rhythm (NSR subjects in clinical application. In the present study, a thorough analysis on the selection of appropriate values of m, r and N for sample entropy (SampEn and recently proposed fuzzy measure entropy (FuzzyMEn is presented for distinguishing two group subjects. 44 long-term NRS and 29 long-term CHF RR interval recordings from http://www.physionet.org were used as the non-pathological and pathological data respectively. Extreme (>2 s and abnormal heartbeat RR intervals were firstly removed from each RR recording and then the recording was segmented with a non-overlapping segment length N of 300 and 1000, respectively. SampEn and FuzzyMEn were performed for each RR segment under different parameter combinations: m of 1, 2, 3 and 4, and r of 0.10, 0.15, 0.20 and 0.25 respectively. The statistical significance between NSR and CHF groups under each combination of m, r and N was observed. The results demonstrated that the selection of m, r and N plays a critical role in determining the SampEn and FuzzyMEn outputs. Compared with SampEn, FuzzyMEn shows a better regularity when selecting the parameters m and r. In addition, FuzzyMEn shows a better relative consistency for distinguishing the two groups, that is, the results of FuzzyMEn in the NSR group were consistently lower than those in the CHF group while SampEn were not. The selections of m of 2 and 3 and r of 0.10 and 0.15 for SampEn and the selections of m of 1 and 2 whenever r (herein

  20. Repeated quantitative perfusion and contrast permeability measurement in the MRI examination of a CNS tumor

    Energy Technology Data Exchange (ETDEWEB)

    Vonken, E.P.A.; Osch, M.J.P. van; Willems, P.W.A.; Zwan, A. van der; Bakker, C.J.G.; Viergever, M.A.; Mali, W.P.T.M. [University Hospital Utrecht (Netherlands)

    2000-09-01

    This study reports on the results of quantitative MRI perfusion and contrast permeability measurement on two occasions in one patient. The measurements were separated 81 days in time. The tumor grew considerably in this period, but no change was found with respect to perfusion and contrast permeability. Non-involved white matter values were reproduced to demonstrate repeatability. The presented approach to dynamic susceptibility contrast MRI allows fast and repeatable quantitative assessment of perfusion and is easily integrated in a conventional brain tumor protocol. (orig.)

  1. Validation of SPAMM Tagged MRI Based Measurement of 3D Soft Tissue Deformation

    CERN Document Server

    Moerman, Kevin M; Simms, Ciaran K; Lamerichs, Rolf M; Stoker, Jaap; Nederveen, Aart J

    2016-01-01

    This study presents and validates a novel (non-ECG-triggered) MRI sequence based on SPAtial Modulation of the Magnetization (SPAMM) to non-invasively measure 3D (quasi-static) soft tissue deformations using only six acquisitions (three static and three indentations). In current SPAMM tagged MRI approaches data is typically constructed from many repeated motion cycles. This has so far restricted its application to the measurement of highly repeatable and periodic movements (e.g. cardiac deformation). In biomechanical applications where soft tissue deformation is artificially induced, often by indentation, significant repeatability constraints exist and, for clinical applications, discomfort and health issues generally preclude a large number of repetitions.

  2. Unexpected global impact of VTA dopamine neuron activation as measured by opto-fMRI

    Science.gov (United States)

    Lohani, Sweyta; Poplawsky, Alexander John; Kim, Seong-Gi; Moghaddam, Bita

    2016-01-01

    Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in cognitive and affective processing as well as in psychiatric disorders including schizophrenia, ADHD and substance abuse disorders. In human studies, dopamine-related functions are routinely assessed using functional magnetic resonance imaging (fMRI) measures of blood oxygenation-level dependent (BOLD) signals during the performance of dopamine-dependent tasks. There is, however, a critical void in our knowledge about if and how activation of VTA dopamine neurons specifically influences regional or global fMRI signals. Here we used optogenetics in Th::Cre rats to selectively stimulate VTA dopamine neurons while simultaneously measuring global hemodynamic changes using BOLD and cerebral blood volume-weighted (CBVw) fMRI. Phasic activation of VTA dopamine neurons increased BOLD and CBVw fMRI signals in VTA-innervated limbic regions, including the ventral striatum (nucleus accumbens). Surprisingly, basal ganglia regions that receive sparse or no VTA dopaminergic innervation, including the dorsal striatum and the globus pallidus, were also activated. In fact, the most prominent fMRI signal increase in the forebrain was observed in the dorsal striatum that is not traditionally associated with VTA dopamine neurotransmission. These data establish causation between phasic activation of VTA dopamine neurons and global fMRI signals. They further suggest that mesolimbic and non-limbic basal ganglia dopamine circuits are functionally connected and, thus, provide a potential novel framework for understanding dopamine-dependent functions and interpreting data obtained from human fMRI studies. PMID:27457809

  3. Unexpected global impact of VTA dopamine neuron activation as measured by opto-fMRI.

    Science.gov (United States)

    Lohani, S; Poplawsky, A J; Kim, S-G; Moghaddam, B

    2017-04-01

    Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in cognitive and affective processing as well as in psychiatric disorders, including schizophrenia, depression, attention-deficit hyperactivity disorder and substance abuse disorders. In human studies, dopamine-related functions are routinely assessed using functional magnetic resonance imaging (fMRI) measures of blood oxygenation-level-dependent (BOLD) signals during the performance of dopamine-dependent tasks. There is, however, a critical void in our knowledge about whether and how activation of VTA dopamine neurons specifically influences regional or global fMRI signals. Here, we used optogenetics in Th::Cre rats to selectively stimulate VTA dopamine neurons while simultaneously measuring global hemodynamic changes using BOLD and cerebral blood volume-weighted (CBVw) fMRI. Phasic activation of VTA dopamine neurons increased BOLD and CBVw fMRI signals in VTA-innervated limbic regions, including the ventral striatum (nucleus accumbens). Surprisingly, basal ganglia regions that receive sparse or no VTA dopaminergic innervation, including the dorsal striatum and the globus pallidus, were also activated. In fact, the most prominent fMRI signal increase in the forebrain was observed in the dorsal striatum that is not traditionally associated with VTA dopamine neurotransmission. These data establish causation between phasic activation of VTA dopamine neurons and global fMRI signals. They further suggest that mesolimbic and non-limbic basal ganglia dopamine circuits are functionally connected and thus provide a potential novel framework for understanding dopamine-dependent functions and interpreting data obtained from human fMRI studies.

  4. Cerebrospinal fluid volumetric MRI mapping as a simple measurement for evaluating brain atrophy.

    Science.gov (United States)

    De Vis, J B; Zwanenburg, J J; van der Kleij, L A; Spijkerman, J M; Biessels, G J; Hendrikse, J; Petersen, E T

    2016-05-01

    To assess whether volumetric cerebrospinal fluid (CSF) MRI can be used as a surrogate for brain atrophy assessment and to evaluate how the T2 of the CSF relates to brain atrophy. Twenty-eight subjects [mean age 64 (sd 2) years] were included; T1-weighted and CSF MRI were performed. The first echo data of the CSF MRI sequence was used to obtain intracranial volume, CSF partial volume was measured voxel-wise to obtain CSF volume (VCSF) and the T2 of CSF (T2,CSF) was calculated. The correlation between VCSF/T2,CSF and brain atrophy scores [global cortical atrophy (GCA) and medial temporal lobe atrophy (MTA)] was evaluated. Relative total, peripheral subarachnoidal, and ventricular VCSF increased significantly with increased scores on the GCA and MTA (R = 0.83, 0.78 and 0.78 and R = 0.72, 0.62 and 0.86). Total, peripheral subarachnoidal, and ventricular T2 of the CSF increased significantly with higher scores on the GCA and MTA (R = 0.72, 0.70 and 0.49 and R = 0.60, 0.57 and 0.41). A fast, fully automated CSF MRI volumetric sequence is an alternative for qualitative atrophy scales. The T2 of the CSF is related to brain atrophy and could thus be a marker of neurodegenerative disease. • A 1:11 min CSF MRI volumetric sequence can evaluate brain atrophy. • CSF MRI provides accurate atrophy assessment without partial volume effects. • CSF MRI data can be processed quickly without user interaction. • The measured T 2 of the CSF is related to brain atrophy.

  5. Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

    Science.gov (United States)

    Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

    2016-04-01

    The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

  6. Structural linear measurements in the newborn brain: accuracy of cranial ultrasound compared to MRI

    Energy Technology Data Exchange (ETDEWEB)

    Leijser, Lara M. [Hammersmith Hospital, Imperial College, Department of Paediatrics, London (United Kingdom); Srinivasan, Latha; Cowan, Frances M. [Hammersmith Hospital, Imperial College, Department of Paediatrics, London (United Kingdom); Hammersmith Hospital, Imperial College, Department of Imaging Sciences, London (United Kingdom); Rutherford, Mary A.; Counsell, Serena J.; Allsop, Joanna M. [Hammersmith Hospital, Imperial College, Department of Imaging Sciences, London (United Kingdom)

    2007-07-15

    Structural size in the neonatal brain is of clinical importance. Cranial ultrasonography (cUS) is the primary method used for evaluating the neonatal brain and it is important to know whether linear measurements made using this technique are accurate. To compare linear measurements of different cerebral structures made from neonatal cUS and contemporaneous MRI. Preterm and term infants studies with cUS and MRI on the same day were studied. Linear measurements made using both techniques from many cerebral structures were compared using a paired t-test. A total of 44 sets of scans from 26 preterm and 8 term infants were assessed. Small but significant differences between the cUS and MRI measurements (P<0.05) were found for the ventricular index, the posterior horn depth of the lateral ventricle, the extracerebral space and interhemispheric fissure, and the cortex of the cingulate gyrus. No significant differences were found for any other measurements. Linear measurements from cUS are accurate for most neonatal cerebral structures. Significant differences compared to MRI were found for a few structures, but only for the cortex were the absolute differences marked and possibly of clinical importance. (orig.)

  7. Development of an outdoor MRI system for measuring flow in a living tree

    Science.gov (United States)

    Nagata, Akiyoshi; Kose, Katsumi; Terada, Yasuhiko

    2016-04-01

    An outdoor MRI system for noninvasive, long-term measurements of sap flow in a living tree in its natural environment has been developed. An open-access, 0.2 T permanent magnet with a 160 mm gap was combined with a radiofrequency probe, planar gradient coils, electromagnetic shielding, several electrical units, and a waterproofing box. Two-dimensional cross-sectional images were acquired for a ring-porous tree, and the anatomical structures, including xylem and phloem, were identified. The MRI flow measurements demonstrated the diurnal changes in flow velocity in the stem on a per-pixel basis. These results demonstrate that our outdoor MRI system is a powerful tool for studies of water transport in outdoor trees.

  8. A Novel Earphone Type Sensor for Measuring Mealtime: Consideration of the Method to Distinguish between Running and Meals

    Science.gov (United States)

    Taniguchi, Kazuhiro; Chiaki, Hikaru; Kurosawa, Mami; Nishikawa, Atsushi

    2017-01-01

    In this study, we describe a technique for estimating meal times using an earphone-type wearable sensor. A small optical sensor composed of a light-emitting diode and phototransistor is inserted into the ear hole of a user and estimates the meal times of the user from the time variations in the amount of light received. This is achieved by emitting light toward the inside of the ear canal and receiving light reflected back from the ear canal. This proposed technique allowed “meals” to be differentiated from having conversations, sneezing, walking, ascending and descending stairs, operating a computer, and using a smartphone. Conventional devices worn on the head of users and that measure food intake can vibrate during running as the body is jolted more violently than during walking; this can result in the misidentification of running as eating by these devices. To solve this problem, we used two of our sensors simultaneously: one in the left ear and one in the right ear. This was based on our finding that measurements from the left and right ear canals have a strong correlation during running but no correlation during eating. This allows running and eating to be distinguished based on correlation coefficients, which can reduce misidentification. Moreover, by using an optical sensor composed of a semiconductor, a small and lightweight device can be created. This measurement technique can also measure body motion associated with running, and the data obtained from the optical sensor inserted into the ear can be used to support a healthy lifestyle regarding both eating and exercise. PMID:28134820

  9. A Novel Earphone Type Sensor for Measuring Mealtime: Consideration of the Method to Distinguish between Running and Meals

    Directory of Open Access Journals (Sweden)

    Kazuhiro Taniguchi

    2017-01-01

    Full Text Available In this study, we describe a technique for estimating meal times using an earphone-type wearable sensor. A small optical sensor composed of a light-emitting diode and phototransistor is inserted into the ear hole of a user and estimates the meal times of the user from the time variations in the amount of light received. This is achieved by emitting light toward the inside of the ear canal and receiving light reflected back from the ear canal. This proposed technique allowed “meals” to be differentiated from having conversations, sneezing, walking, ascending and descending stairs, operating a computer, and using a smartphone. Conventional devices worn on the head of users and that measure food intake can vibrate during running as the body is jolted more violently than during walking; this can result in the misidentification of running as eating by these devices. To solve this problem, we used two of our sensors simultaneously: one in the left ear and one in the right ear. This was based on our finding that measurements from the left and right ear canals have a strong correlation during running but no correlation during eating. This allows running and eating to be distinguished based on correlation coefficients, which can reduce misidentification. Moreover, by using an optical sensor composed of a semiconductor, a small and lightweight device can be created. This measurement technique can also measure body motion associated with running, and the data obtained from the optical sensor inserted into the ear can be used to support a healthy lifestyle regarding both eating and exercise.

  10. Brain Metastases from Different Primary Carcinomas: an Evaluation of DSC MRI Measurements.

    Science.gov (United States)

    Zhang, H; Zhang, G; Oudkerk, M

    2012-03-01

    This study evaluated the roles of different dynamic susceptibility contrast magnetic imaging (DSC MRI) measurements in discriminating between brain metastases derived from four common primary carcinomas. Thirty-seven patients with brain metastases were enrolled. Relative cerebral blood volume (rCBV), cerebral blood flow (rCBF) and relative mean transit time (rMTT) in both tumor and peritumoral edema were measured. Metastases were grouped by their primary tumor (lung, gastrointestinal, breast and renal cell carcinoma). DSC MRI measurements were compared between groups. Mean rCBV, rCBF, rMTT in tumor and peritumoral edema of all brain metastases (n=37) were 2.79 ± 1.73, 2.56 ± 2.11, 1.21 ± 0.48 and 1.05 ± 0.53, 0.86 ± 0.40, 1.99 ± 0.41, respectively. The tumoral rCBV (5.26 ± 1.89) and rCBF (5.32 ± 3.28) of renal metastases were greater than those of the other three metastases (P0.05). Evaluating various DSC MRI measurements can provide complementary hemodynamic information on brain metastases. The tumoral rCBV, rCBF and likely rMTT can help discriminate between brain metastases originating from different primary carcinomas. The peritumoral DSC MRI measurements had limited value in discriminating between brain metastases.

  11. Neural Substrates of the Topology Test to Measure Fluid Reasoning: An fMRI Study

    Science.gov (United States)

    Masunaga, Hiromi; Kawashima, Ryuta; Horn, John L.; Sassa, Yuko; Sekiguchi, Atsushi

    2008-01-01

    In our prior study the negative correlation between Topology, a behavioral measure of fluid reasoning, and adult age diminished with the increase in the level of expertise in a cognitively-demanding domain of expertise in the game of GO. The present fMRI study was designed to investigate neural substrates of Topology. The modified topology…

  12. Multimodality correlations of patellar height measurement on X-ray, CT, and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Pearlene P.; Chalian, Majid; Carrino, John A.; Eng, John; Chhabra, Avneesh [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States)

    2012-10-15

    To investigate whether the universally accepted range of normal patellar height ratios derived from radiography for the Insall-Salvati (IS) and Blackburne-Peel (BP) methods could be similarly applied to both CT and MRI. Institutional review board approval was obtained with waiver of informed consent for this HIPPA-compliant study. A total of 45 knees in 42 patients (15 men, 27 women; age range 11 to 75 years, mean age 39 {+-} 20 years) who underwent tri-modality (radiograph, CT, and MRI) examinations were selected. All patients had knee imaging obtained for a variety of reasons and measurements were performed by two independent readers who were blinded to each other's measurements or the respective measurements derived from each of the methods. Paired t test was used to compare the mean values among the modalities. Inter-observer and inter-method agreements were assessed using intra-class correlation coefficients. Statistically significant, but small quantitative differences are noted between tri-modality patellar height ratios. For comparable results, the small addition of 0.13 and 0.10 are needed for the Insall-Salvati measurements on MRI and CT respectively, compared with radiographs. For the Blackburne-Peel ratio, an additional adjustment of 0.09 is needed between radiographs and MRI, but not between radiographs and CT. These adjustments are independent of gender. The interobserver reproducibility was excellent (ICC {>=} 0.94) for both the Insall-Salvati and Blackburne-Peel methods for all modalities. The results indicate that cut-off values for patella alta and baja derived from radiographs should not be directly transposed to CT and MRI; however, the adjustments are relatively minor. These measurements show excellent reproducibility for all modalities currently used for patellar height measurements. (orig.)

  13. Noninvasive Measurement of Conductivity Anisotropy at Larmor Frequency Using MRI

    OpenAIRE

    Joonsung Lee; Yizhuang Song; Narae Choi; Sungmin Cho; Jin Keun Seo; Dong-Hyun Kim

    2013-01-01

    Anisotropic electrical properties can be found in biological tissues such as muscles and nerves. Conductivity tensor is a simplified model to express the effective electrical anisotropic information and depends on the imaging resolution. The determination of the conductivity tensor should be based on Ohm's law. In other words, the measurement of partial information of current density and the electric fields should be made. Since the direct measurements of the electric fiel...

  14. The Characteristics of Vascular Growth in VX2 Tumor Measured by MRI and Micro-CT

    Directory of Open Access Journals (Sweden)

    X.-L. Qi

    2012-01-01

    Full Text Available Blood supply is crucial for rapid growth of a malignant tumor; medical imaging can play an important role in evaluating the vascular characterstics of tumors. Magnetic resonance imaging (MRI and micro-computed tomography (CT are able to detect tumors and measure blood volumes of microcirculation in tissue. In this study, we used MR imaging and micro-CT to assess the microcirculation in a VX2 tumor model in rabbits. MRI characterization was performed using the intravascular contrast agent Clariscan (NC100150-Injection; micro-CT with Microfil was used to directly depict blood vessels with diameters as low as 17 um in tissue. Relative blood volume fraction (rBVF in the tumor rim and blood vessel density (rBVD over the whole tumor was calculated using the two imaging methods. Our study indicates that rBVF is negatively related to the volume of the tumor measured by ultrasound (R=0.90. rBVF in the tissue of a VX2 tumor measured by MRI in vivo was qualitatively consistent with the rBVD demonstrated by micro-CT in vitro (R=0.97. The good correlation between the two methods indicates that MRI studies are potentially valuable for assessing characteristics or tumor vascularity and for assessing response to therapy noninvasively.

  15. Renal masses measuring under 2 cm: Pathologic outcomes and associations with MRI features

    Energy Technology Data Exchange (ETDEWEB)

    Rosenkrantz, Andrew B., E-mail: Andrew.Rosenkrantz@nyumc.org [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Wehrli, Natasha E. [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Melamed, Jonathan [Department of Pathology, 550 First Avenue, New York, NY 10016 (United States); Taneja, Samir S. [Department of Urology, Division of Urologic Oncology, 550 First Avenue, New York, NY 10016 (United States); Shaikh, Mohammed B. [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States)

    2014-08-15

    Purpose: To evaluate pathologic outcomes and associations with MRI features in small renal masses measuring up to 20 mm Methods: 86 patients (61 ± 13 years; 45 M/41F) with 92 renal masses measuring up to 20 mm that underwent MRI prior to tissue diagnosis were included. Two radiologists independently evaluated all masses for microscopic lipid, hemorrhage, T2-hyperintensity, T2-homogeneity, cystic/necrotic areas, hypervascularity, enhancement homogeneity, circumscribed margins, and predominantly exophytic location. These MRI features, as well as patient age, gender, and history of RCC, were compared with pathologic findings using Fisher's exact test, unpaired t-test, and multivariate logistic regression. Results: 26.1% (24/92) of masses under 2 cm were benign, only 32.6% (30/92) were clear-cell RCC, and only 7.6% (7/92) were high-grade. Among 16 masses measuring up to 1 cm, only 12.5% (2/16) were clear-cell RCC, and none was high-grade. Within the entire cohort, no MRI or clinical feature showed a significant difference between benign and malignant lesions (p ≥ 0.053). However, for both readers, clear-cell RCC exhibited a significantly higher frequency of T2-hyperintensity, cystic/necrotic areas, and hypervascularity, and a significantly lower frequency of hemorrhage, T2-homogeneity, and enhancement homogeneity (p < 0.001–0.036). Hypervascularity was a significant independent predictor of clear-cell RCC for both readers (p = 0.002–0.007), as was T2-hyperintensity for reader 2 (p = 0.007). Conclusion: A substantial fraction of small renal masses were benign, and when malignant, largely exhibited indolent pathologic characteristics, particularly when measuring under 1 cm Although small benign and malignant masses could not be differentiated on MRI, hypervascularity showed a significant independent association with clear-cell RCC in comparison with other lesions.

  16. On the comparison between MRI and US imaging for human heel pad thickness measurements

    DEFF Research Database (Denmark)

    Matteoli, Sara; Corbin, Nadège Corbin; Wilhjelm, Jens E.;

    2011-01-01

    The human heel pad thickness, defined as the shortest distance between the calcaneus and heel skin, is one of the intrinsic factor which must be taken into account when investigating the biomechanics of the heel pad. US and MRI are the preferable imaging modalities used to measure the heel pad...... thickness as they are both ionizing-free radiations. The aim of this paper is to measure the bone to skin distance of nine heel pad phantoms from MRI and US images, and to compare the results with a true value (TV) in order to find the errors. Paired sample t-test was used to compare the measurements......1530 (P-value=0.402). Results confirm the necessity to investigate on the real speed of sound for the heel pad tissues, in order to have realistic measurements when dealing with human heel pads. __________________________________________________________________________________________________________...

  17. Combining Two Large MRI Data Sets (AddNeuroMed and ADNI) Using Multivariate Data Analysis to Distinguish between Patients with Alzheimer's Disease and Healthy Controls

    DEFF Research Database (Denmark)

    Westman, Eric; Simmons, Andrew; Muehlboeck, J.-Sebastian

    and the high resolution sagital 3D T1w MP-RAGE datasets used for image analysis. Regional segmentation of the brain was carried out using the multi-scale ANIMAL image analysis technique (Automated Non-linear Image Matching and Anatomical Labeling). Cortical thickness measurements were performed using CLASP...

  18. Ensuring safety and functionality of electroglottography measurements during dynamic pulmonary MRI.

    Science.gov (United States)

    Özen, Ali Caglar; Traser, Louisa; Echternach, Matthias; Dadakova, Tetiana; Burdumy, Michael; Richter, Bernhard; Bock, Michael

    2016-11-01

    To combine vocal tract measurements with dynamic MRI of the lungs to provide fundamental insights into the lung physiology during singing. To analyze vocal fold oscillatory patterns during dynamic lung MRI, an electroglottography (EGG) system was modified to allow for simultaneous EGG measurements during MR image acquisitions. A low-pass filter was introduced to suppress residual radiofrequency (RF) coupling into the EGG signal. RF heating was tested in a gel phantom to ensure MR safety, and functionality of the EGG device was assessed in a volunteer experiment at singing frequencies from A5 to A3. In the recorded EGG signals, remaining RF interferences were removed by independent component analysis post processing, and standard EGG parameters such as fundamental frequency, contact quotient and jitter were calculated. In a second volunteer experiment, EGG recordings were compared with lung diameter measurements from 2D time-resolved trueFISP acquisitions. RF heating measurements resulted in less than 1.2°C temperature increase in the gel phantom. EGG parameters measured during MR imaging are within the range of ideal values. In the lung measurement, both the lung diameter and the EGG recordings could be successfully performed with only minimal interference. EGG recording is pos sible during dynamic lung MRI, and glottal activity can be studied safely at 1.5T. Magn Reson Med 76:1629-1635, 2016. © 2015 International Society for Magnetic Resonance in Medicine. © 2015 International Society for Magnetic Resonance in Medicine.

  19. Visual grading of 2D and 3D functional MRI compared with image-based descriptive measures

    Energy Technology Data Exchange (ETDEWEB)

    Ragnehed, Mattias [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences, Division of Radiological Sciences/Radiology, Faculty of Health Sciences, Linkoeping (Sweden); Leinhard, Olof Dahlqvist; Pihlsgaard, Johan; Lundberg, Peter [Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Linkoeping University, Division of Radiological Sciences, Radiation Physics, IMH, Linkoeping (Sweden); Wirell, Staffan [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University Hospital, Department of Radiology, Linkoeping (Sweden); Soekjer, Hannibal; Faegerstam, Patrik [Linkoeping University Hospital, Department of Radiology, Linkoeping (Sweden); Jiang, Bo [Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Smedby, Oerjan; Engstroem, Maria [Linkoeping University, Division of Radiological Sciences, Radiology, IMH, Linkoeping (Sweden); Linkoeping University, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden)

    2010-03-15

    A prerequisite for successful clinical use of functional magnetic resonance imaging (fMRI) is the selection of an appropriate imaging sequence. The aim of this study was to compare 2D and 3D fMRI sequences using different image quality assessment methods. Descriptive image measures, such as activation volume and temporal signal-to-noise ratio (TSNR), were compared with results from visual grading characteristics (VGC) analysis of the fMRI results. Significant differences in activation volume and TSNR were not directly reflected by differences in VGC scores. The results suggest that better performance on descriptive image measures is not always an indicator of improved diagnostic quality of the fMRI results. In addition to descriptive image measures, it is important to include measures of diagnostic quality when comparing different fMRI data acquisition methods. (orig.)

  20. Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

    Energy Technology Data Exchange (ETDEWEB)

    Meckel, Stephan [University Hospital Freiburg, Department of Neuroradiology, Freiburg (Germany); Leitner, Lorenz; Schubert, Tilman [University Hospital Basel, Institute of Radiology, Basel (Switzerland); Bonati, Leo H.; Lyrer, Philippe [University Hospital Basel, Department of Neurology, Basel (Switzerland); Santini, Francesco [University Hospital Basel, Department of Radiological Physics, Institute of Radiology, Basel (Switzerland); Stalder, Aurelien F. [Xuanwu Hospital - Capital Medical University, Department of Radiology, Beijing (China); Markl, Michael [Northwestern University Feinberg School of Medicine, Departments of Radiology and Biomedical Engineering, Chicago (United States); Wetzel, Stephan G. [Neuroradiology, Swiss Neuro Institute, Klinik Hirslanden, Zurich (Switzerland)

    2013-04-15

    4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

  1. MRI markers for mild cognitive impairment: comparisons between white matter integrity and gray matter volume measurements.

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    Full Text Available The aim of the study was to evaluate the value of assessing white matter integrity using diffusion tensor imaging (DTI for classification of mild cognitive impairment (MCI and prediction of cognitive impairments in comparison to brain atrophy measurements using structural MRI. Fifty-one patients with MCI and 66 cognitive normal controls (CN underwent DTI and T1-weighted structural MRI. DTI measures included fractional anisotropy (FA and radial diffusivity (DR from 20 predetermined regions-of-interest (ROIs in the commissural, limbic and association tracts, which are thought to be involved in Alzheimer's disease; measures of regional gray matter (GM volume included 21 ROIs in medial temporal lobe, parietal cortex, and subcortical regions. Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex. Group classifications based on FA or DR was significant and better than classifications based on GM volume. Using either DR or FA together with GM volume improved classification accuracy. Furthermore, all three measures, FA, DR and GM volume were similarly accurate in predicting cognitive performance in MCI patients. Taken together, the results imply that DTI measures are as accurate as measures of GM volume in detecting brain alterations that are associated with cognitive impairment. Furthermore, a combination of DTI and structural MRI measurements improves classification accuracy.

  2. Dynamic measurement of patello-femoral joint alignment using weight-bearing magnetic resonance imaging (WB-MRI).

    Science.gov (United States)

    Mariani, Silvia; La Marra, Alice; Arrigoni, Francesco; Necozione, Stefano; Splendiani, Alessandra; Di Cesare, Ernesto; Barile, Antonio; Masciocchi, Carlo

    2015-12-01

    Aim of our work was to compare standard and weight-bearing WB-MRI to define their contribution in unmasking patello-femoral (PF) maltracking and to define what measurement of patellar alignment is the most reliable. We prospectively collected 95 non consecutive patients, clinically divided into 2 groups: group A (the control group), including 20 patients (negative for patellar maltracking), and group B including 75 patients (positive for patellar maltracking). The patients underwent a dedicated 0.25 T MRI, in supine and WB position, with knee flexion of 12-15°. The following measurements were performed: Insall-Salvati index (IS), lateral patellar displacement (LPD), lateral patello-femoral angle (LPA) and lateral patellar tilt (LPT). Quantitative and qualitative statistical analyses were performed to compare the results obtained before and after WB-MRI. Measurements were subsequently performed on both groups. Group A patients showed no statistically significant variations at all measurements both on standard and WB-MRI. On the basis of measurements made on standard MRI, group B patients were divided into group B1 (23 patients) (negative or positive at 1 measurement) and group B2 (52 patients) (positive at 2 or more measurements). After WB-MRI, group B1 patients were divided into group B1a (6 patients), in case they remained positive at 0/1 measurement, and group B1b (17 patients), in case they became positive at 2 or more measurements. All group B2 patients confirmed to be positive at 2 or more measurements at WB-MRI. Quantitative statistical analysis showed that LPT and LPA were the most reproducible and clinically useful measurements. Qualitative statistical analysis performed on standard and WB-MRI demonstrated that LPT was the best predictive measurement. This study demonstrates both the high diagnostic value of WB-MRI in unmasking PF-maltracking and the best predictive value of LPT measurement. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Automated measurement of the human corpus callosum using MRI

    Directory of Open Access Journals (Sweden)

    Timothy J Herron

    2012-09-01

    Full Text Available The corpus callosum includes the majority of fibers that connect the two cortical hemispheres. Studies of cross-sectional callosal morphometry and area have revealed developmental, gender, and hemispheric differences in healthy populations and callosal deficits associated with neurodegenerative disease and brain injury. However, accurate quantification of the callosum using magnetic resonance imaging is complicated by intersubject variability in callosal size, shape, and location and often requires manual outlining of the callosum in order to achieve adequate performance. Here we describe an objective, fully automated protocol that utilizes voxel-based image to quantify the area and thickness both of the entire callosum and of different callosal compartments. We verify the method’s accuracy, reliability, robustness and multisite consistency and make comparisons with manual measurements using public brain-image databases. An analysis of age-related changes in the callosum showed increases in length and reductions in thickness and area with age. A comparison of older subjects with and without mild dementia revealed that reductions in anterior callosal area independently predicted poorer cognitive performance after factoring out Mini-Mental Status Examination scores and normalized whole brain volume. Open-source software implementing the algorithm is available at www.nitrc.org/projects/c8c8.

  4. Occupational exposure measurements of static and pulsed gradient magnetic fields in the vicinity of MRI scanners.

    Science.gov (United States)

    Kännälä, Sami; Toivo, Tim; Alanko, Tommi; Jokela, Kari

    2009-04-07

    Recent advances in magnetic resonance imaging (MRI) have increased occupational exposure to magnetic fields. In this study, we examined the assessment of occupational exposure to gradient magnetic fields and time-varying magnetic fields generated by motion in non-homogeneous static magnetic fields of MRI scanners. These magnetic field components can be measured simultaneously with an induction coil setup that detects the time rate of change of magnetic flux density (dB/dt). The setup developed was used to measure the field components around two MRI units (1 T open and 3 T conventional). The measured values can be compared with dB/dt reference levels derived from magnetic flux density reference levels given by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The measured motion-induced dB/dt values were above the dB/dt reference levels for both MRI units. The measured values for the gradient fields (echo planar imaging (EPI) and fast field echo (FFE) sequences) also exceeded the dB/dt reference levels in positions where the medical staff may have access during interventional procedures. The highest motion-induced dB/dt values were 0.7 T s(-1) for the 1 T scanner and 3 T s(-1) for the 3 T scanner when only the static field was present. Even higher values (6.5 T s(-1)) were measured for simultaneous exposure to motion-induced and gradient fields in the vicinity of the 3 T scanner.

  5. In vivo MRI volumetric measurement of prostate regression and growth in mice

    Directory of Open Access Journals (Sweden)

    Nalcioglu Orhan

    2007-07-01

    Full Text Available Abstract Background Mouse models for treatment of late-stage prostate cancer are valuable tools, but assessing the extent of growth of the prostate and particularly its regression due to therapeutic intervention or castration is difficult due to the location, small size and interdigitated anatomy of the prostate gland in situ. Temporal monitoring of mouse prostate regression requires multiple animals and examination of histological sections. Methods Initially, T2-weighted magnetic resonance imaging (MRI was performed on normal year-old C57/BL6 mice. Individual mice were repeatedly imaged using inhalation anesthesia to establish the reproducibility of the method and to follow hormone manipulation of the prostate volume. Subsequently, MRI fat signal was suppressed using a chemical shift-selective (CHESS pulse to avoid signal contamination and enhance discrimination of the prostate. Results High field (7T MRI provides high resolution (117 × 117 μm in plane, highly reproducible images of the normal mouse prostate. Despite long imaging times, animals can be imaged repeatedly to establish reliability of volume measurements. Prostate volume declines following castration and subsequently returns to normal with androgen administration in the same animal. CHESS imaging allowed discrimination of both the margins of the prostate and the dorsal-lateral lobes of the prostate (DLP from the ventral lobes (VP. Castration results in a 40% reduction in the volume of the DLP and a 75% reduction in the volume of the VP. Conclusion MRI assessment of the volume of the mouse prostate is precise and reproducible. MRI improves volumetric determination of the extent of regression and monitoring of the same mouse over time during the course of treatment is possible. Since assessing groups of animals at each time point is avoided, this improves the accuracy of the measurement of any manipulation effect and reduces the number of animals required.

  6. Cerebrospinal fluid volumetric MRI mapping as a simple measurement for evaluating brain atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Vis, J.B. de; Zwanenburg, J.J.; Kleij, L.A. van der; Spijkerman, J.M.; Hendrikse, J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Biessels, G.J. [University Medical Center Utrecht, Department of Neurology, Brain Center Rudolf Magnus, Utrecht (Netherlands); Petersen, E.T. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Hvidovre Hospital, Danish Research Centre for Magnetic Resonance, Hvidovre (Denmark)

    2016-05-15

    To assess whether volumetric cerebrospinal fluid (CSF) MRI can be used as a surrogate for brain atrophy assessment and to evaluate how the T{sub 2} of the CSF relates to brain atrophy. Twenty-eight subjects [mean age 64 (sd 2) years] were included; T{sub 1}-weighted and CSF MRI were performed. The first echo data of the CSF MRI sequence was used to obtain intracranial volume, CSF partial volume was measured voxel-wise to obtain CSF volume (V{sub CSF}) and the T{sub 2} of CSF (T{sub 2,CSF}) was calculated. The correlation between V{sub CSF} / T{sub 2,CSF} and brain atrophy scores [global cortical atrophy (GCA) and medial temporal lobe atrophy (MTA)] was evaluated. Relative total, peripheral subarachnoidal, and ventricular V{sub CSF} increased significantly with increased scores on the GCA and MTA (R = 0.83, 0.78 and 0.78 and R = 0.72, 0.62 and 0.86). Total, peripheral subarachnoidal, and ventricular T{sub 2} of the CSF increased significantly with higher scores on the GCA and MTA (R = 0.72, 0.70 and 0.49 and R = 0.60, 0.57 and 0.41). A fast, fully automated CSF MRI volumetric sequence is an alternative for qualitative atrophy scales. The T{sub 2} of the CSF is related to brain atrophy and could thus be a marker of neurodegenerative disease. (orig.)

  7. Self-Reported Measures Of Strength And Sport-Specific Skills Distinguish Ranking In An International Online Fitness Competition.

    Science.gov (United States)

    Serafini, Paul R; Feito, Yuri; Mangine, Gerald T

    2017-02-08

    To determine if self-reported performance measures could distinguish ranking during the 2016 CrossFit Open, data from three thousand male (n=1500; 27.2±8.4 y; 85.2±7.9 kg; 177.0±6.5 cm) and female (n=1500, 28.7±4.9 y; 63.7±5.8 kg; 163.7±6.6 cm) competitors was used for this study. Competitors were split by gender and grouped into quintiles (Q1-Q5) based upon their final ranking. Quintiles were compared for one-repetition maximum (1RM) squat, deadlift, clean and jerk (CJ), snatch, 400-m sprint, 5,000-m run, and benchmark workouts (Fran, Helen, Grace, Filthy-50, and Fight-gone-bad). Separate one-way analyses of variance revealed all competitors in Q1 reported greater (p<0.05) 1RM loads for squat (Males: 201.6±19.1 kg; Females: 126.1±13.0 kg), deadlift (Males: 232.4±20.5 kg; Females: 148.3±14.5 kg), CJ (Males: 148.9±12.1 kg; Females: 95.7±8.4 kg), and snatch (Males: 119.4±10.9 kg; Females 76.5±7.6 kg) compared to other quintiles. In addition, Males in Q1 (59.3±5.9 sec) reported faster (p<0.05) 400-m times than Q3 only (62.6±7.3 sec), but were not different from any group in the 5,000-m run. Females in Q2 (67.5 ± 8.8 sec) reported faster (p<0.05) 400-m times than Q3-Q5 (73.5-74.8 sec) and faster (21.3 ± 1.8 min, p<0.02) 5,000-m times than Q4 (22.6±2.2 min) and Q5 (22.6±1.9 min). Faster (p<0.05) Fran times were reported by Q1 (males: 138.2±13.3 sec; females: 159.4±28.3 sec) compared to other groups, while the results of other workouts were variable. These data indicate that the most successful athletes excel in all areas of fitness/skill, while lower-ranking athletes should focus on developing strength and power after achieving sufficient proficiency in sport-specific skills.

  8. Quantitative measurement of cerebral oxygen extraction fraction using MRI in patients with MELAS.

    Directory of Open Access Journals (Sweden)

    Lei Yu

    Full Text Available OBJECTIVE: To quantify the cerebral OEF at different phases of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS by using MRI. METHODS: We recruited 32 patients with MELAS confirmed by gene analysis. Conventional MRI scanning, as well as functional MRI including arterial spin labeling and oxygen extraction fraction imaging, was undertaken to obtain the pathological and metabolic information of the brains at different stages of stroke-like episodes in patients. A total of 16 MRI examinations at the acute and subacute phase and 19 examinations at the interictal phase were performed. In addition, 24 healthy volunteers were recruited for control subjects. Six regions of interest were placed in the anterior, middle, and posterior parts of the bilateral hemispheres to measure the OEF of the brain or the lesions. RESULTS: OEF was reduced significantly in brains of patients at both the acute and subacute phase (0.266 ± 0.026 and at the interictal phase (0.295 ± 0.009, compared with normal controls (0.316 ± 0.025. In the brains at the acute and subacute phase of the episode, 13 ROIs were prescribed on the stroke-like lesions, which showed decreased OEF compared with the contralateral spared brain regions. Increased blood flow was revealed in the stroke-like lesions at the acute and subacute phase, which was confined to the lesions. CONCLUSION: MRI can quantitatively show changes in OEF at different phases of stroke-like episodes. The utilization of oxygen in the brain seems to be reduced more severely after the onset of episodes in MELAS, especially for those brain tissues involved in the episodes.

  9. 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.

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ... Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ... Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top ...

  12. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan; Fiehler, Jens [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neuroradiology; Reitz, Matthias; Schmidt, Nils O. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neurosurgery; Bolar, Divya S. [Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States). Radiology; Adalsteinsson, Elfar [Massachusetts Institute of Technology, Cambridge, MA (United States). Electrical Engineering and Computer Science

    2015-05-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s {sup and} -1] = 20.7/20.4/20.1, R2*[s {sup and} -1] = 31.6/29.6/25.9, R2'[s {sup and} 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min {sup and} -1.100g {sup and} -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood

  13. Cine-MRI versus two-dimensional echocardiography to measure in vivo left ventricular function in rat heart.

    Science.gov (United States)

    Stuckey, Daniel J; Carr, Carolyn A; Tyler, Damian J; Clarke, Kieran

    2008-08-01

    Two-dimensional echocardiography is the most commonly used non-invasive method for measuring in vivo cardiac function in experimental animals. In humans, measurements of cardiac function made using cine-MRI compare favourably with those made using echocardiography. However, no rigorous comparison has been made in small animals. Here, standard short-axis two-dimensional (2D) echocardiography (2D-echo) and cine-MRI measurements were made in the same rats, both control and after chronic myocardial infarction. Correlations between the two techniques were found for end diastolic area, stroke area and ejection fraction, but cine-MRI measurements of ejection fraction were 12+/-6% higher than those made using 2D-echo, because of the 1.8-fold higher temporal resolution of the MRI technique (4.6 ms vs 8.3 ms). Repeated measurements on the same group of rats over several days showed that the cine-MRI technique was more reproducible than 2D-echo, in that 2D-echo would require five times more animals to find a statistically significant difference. In summary, caution should be exercised when comparing functional results acquired using short-axis 2D-echo vs cine-MRI. The accuracy of cine-MRI allows identification of alterations in heart function that may be missed when using 2D-echo.

  14. N-methyl-D-aspartate receptor encephalitis mediates loss of intrinsic activity measured by functional MRI.

    Science.gov (United States)

    Brier, Matthew R; Day, Gregory S; Snyder, Abraham Z; Tanenbaum, Aaron B; Ances, Beau M

    2016-06-01

    Spontaneous brain activity is required for the development and maintenance of normal brain function. Many disease processes disrupt the organization of intrinsic brain activity, but few pervasively reduce the amplitude of resting state blood oxygen level dependent (BOLD) fMRI fluctuations. We report the case of a female with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, longitudinally studied during the course of her illness to determine the contribution of NMDAR signaling to spontaneous brain activity. Resting state BOLD fMRI was measured at the height of her illness and 18 weeks following discharge from hospital. Conventional resting state networks were defined using established methods. Correlation and covariance matrices were calculated by extracting the BOLD time series from regions of interest and calculating either the correlation or covariance quantity. The intrinsic activity was compared between visits, and to expected activity from 45 similarly aged healthy individuals. Near the height of the illness, the patient exhibited profound loss of consciousness, high-amplitude slowing of the electroencephalogram, and a severe reduction in the amplitude of spontaneous BOLD fMRI fluctuations. The patient's neurological status and measures of intrinsic activity improved following treatment. We conclude that NMDAR-mediated signaling plays a critical role in the mechanisms that give rise to organized spontaneous brain activity. Loss of intrinsic activity is associated with profound disruptions of consciousness and cognition.

  15. Ischiofemoral space on MRI in an asymptomatic population: Normative width measurements and soft tissue signal variations

    Energy Technology Data Exchange (ETDEWEB)

    Maras Oezdemir, Zeynep; Goermeli, Cemile Ayse; Sagir Kahraman, Ayseguel [Inoenue University School of Medicine, Department of Radiology, Malatya (Turkey); Aydingoez, Uestuen [Hacettepe University School of Medicine, Department of Radiology, Ankara (Turkey)

    2015-08-15

    To make normative width measurements of the ischiofemoral (IF) space in an asymptomatic population and to record soft tissue MRI signal variations within the IF space in order to determine whether such variations are associated with IF space dimensions. Normative width measurements of the IF space were prospectively made in 418 hips on 1.5 T MR images of 209 asymptomatic volunteers. Quantitative and qualitative assessments of the IF soft tissues including the quadratus femoris (QF) muscle were also made. The mean IF space width was 2.56 ± 0.75 cm (right, 2.60 ± 0.75 cm; left, 2.53 ± 0.75 cm). Soft tissue MRI signal abnormalities were present within the IF space in 19 (9.1 %) of 209 volunteers. Soft tissue abnormalities within the IF space included oedema (3/209, 1.4 %) of the QF and/or surrounding soft tissue, and only fatty infiltration (16/209, 7.7 %) of the QF. Bilateral IF spaces are asymmetrical in asymptomatic persons. There is ≥10 % of width difference between right and left IF spaces in approximately half of asymptomatic individuals. Fatty infiltration and oedema can be present at the IF space in a small portion of the asymptomatic population, who also have narrower IF spaces than those without soft tissue MRI signal abnormalities. (orig.)

  16. The usefulness of 3D quantitative analysis with using MRI for measuring osteonecrosis of the femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ji Young; Lee, Sun Wha [Ewha Womans University College of Medicine, Seoul (Korea, Republic of); Park, Youn Soo [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2006-11-15

    We wanted to evaluate the usefulness of MRI 3D quantitative analysis for measuring osteonecrosis of the femoral head in comparison with MRI 2D quantitative analysis and quantitative analysis of the specimen. For 3 months at our hospital, 14 femoral head specimens with osteonecrosis were obtained after total hip arthroplasty. The patients preoperative MRIs were retrospectively reviewed for quantitative analysis of the size of the necrosis. Each necrotic fraction of the femoral head was measured by 2D quantitative analysis with using mid-coronal and mid-sagittal MRIs, and by 3D quantitative analysis with using serial continuous coronal MRIs and 3D reconstruction software. The necrotic fraction of the specimen was physically measured by the fluid displacement method. The necrotic fraction according to MRI 2D or 3D quantitative analysis was compared with that of the specimen by using Spearman's correlation test. On the correlative analysis, the necrotic fraction by MRI 2D quantitative analysis and quantitative analysis of the specimen showed moderate correlation (r = 0.657); on the other hand, the necrotic fraction by MRI 3D quantitative analysis and quantitative analysis of the specimen demonstrated a strong correlation (r = 0.952) ({rho} < 0.05). MRI 3D quantitative analysis was more accurate than 2D quantitative analysis using MRI for measuring osteonecrosis of the femoral head. Therefore, it may be useful for predicting the clinical outcome and deciding the proper treatment option.

  17. On the characterization of single-event related brain activity from functional Magnetic Resonance Imaging (fMRI) measurements

    KAUST Repository

    Khoram, Nafiseh

    2014-08-01

    We propose an efficient numerical technique for calibrating the mathematical model that describes the singleevent related brain response when fMRI measurements are given. This method employs a regularized Newton technique in conjunction with a Kalman filtering procedure. We have applied this method to estimate the biophysiological parameters of the Balloon model that describes the hemodynamic brain responses. Illustrative results obtained with both synthetic and real fMRI measurements are presented. © 2014 IEEE.

  18. Measuring the mutual effects between a CZT detector and MRI for the development of a simultaneous MBI/MRI insert

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Ashley [McMaster University (Canada); Farncombe, Troy [Hamilton Health Sciences (Canada); Noseworthy, Michael [McMaster University (Canada)

    2015-05-18

    While mammography is the gold standard for breast cancer screening, it suffers from poor sensitivity in women with dense breast tissue. Both breast MRI and molecular breast imaging (MBI) have been used as secondary imaging techniques. However, breast MRI suffers from low specificity and low sensitivity in MBI. A CZT based detector system has been developed with the goal of simultaneous MBI/MRI imaging to address the shortcomings of each modality. The performance of each modality needs to be addressed separately and together. The CZT system is comprised of four Redlen CZT modules tiled in a 2x2 array. Each module consists of 256 pixels and feature a builtin on-board ASIC and FPGA. A custom digital readout circuit board was designed to interface the four modules with a microcontroller to a PC. MR images were acquired with a 3T GE Discovery MR750 and Hologic breast coils. A gradient echo imaging sequence was used for all image acquisitions. A tissue mimicking phantom with a plastic grid insert (1 cm spacing) was used to evaluate geometric accuracy with the CZT detectors in the MRI bore. The average distance between the grid markers was 1Å 0.2cm indicating negligible geometric distortion. Field maps were generated with a uniform phantom to quantify the effect on magnetic field homogeneity. Early results indicate a significant distortion (~10ppm) in the magnetic field closest to the coil. Further analysis of the MR images will determine the extent of image quality degradation. A flood map of Tc-99m was acquired to evaluate and implement an energy correction map and a uniformity map. In the absence of a magnetic field, the mean energy resolution at 140keV was 6.3%. After fully characterizing the uniformity, geometric accuracy and sensitivity, the same metrics will be evaluated in the MRI bore.

  19. Multimodal classification of schizophrenia patients with MEG and fMRI data using static and dynamic connectivity measures

    Directory of Open Access Journals (Sweden)

    Mustafa Sinan Cetin

    2016-10-01

    Full Text Available Mental disorders like schizophrenia are currently diagnosed by physicians/psychiatrists through clinical assessment and their evaluation of patient’s self-reported experiences as the illness emerges. There is great interest in identifying biological markers of prognosis at the onset of illness, rather than relying on the evolution of symptoms across time. Functional network connectivity, which indicates a subject's overall level of 'synchronicity' of activity between brain regions, demonstrates promise in providing individual subject predictive power. Many previous studies reported functional connectivity changes during resting-state using only functional magnetic resonance imaging (fMRI. Nevertheless, exclusive reliance on fMRI to generate such networks may limit the inference of the underlying dysfunctional connectivity, which is hypothesized to be a factor in patient symptoms, as fMRI measures connectivity via hemodynamics. Therefore, combination of connectivity assessments using fMRI and magnetoencephalography (MEG, which more directly measures neuronal activity, may provide improved classification of schizophrenia than either modality alone. Moreover, recent evidence indicates that metrics of dynamic connectivity may also be critical for understanding pathology in schizophrenia. In this work, we propose a new framework for extraction of important disease related features and classification of patients with schizophrenia based on using both fMRI and MEG to investigate functional network components in the resting state. Results of this study show that the integration of fMRI and MEG provides important information that captures fundamental characteristics of functional network connectivity in schizophrenia and is helpful for prediction of schizophrenia patient group membership. Combined fMRI/MEG methods, using static functional network connectivity analyses, improved classification accuracy relative to use of fMRI or MEG methods alone (by 15

  20. Gas-liquid Phase Distribution and Void Fraction Measurements Using the MRI

    Science.gov (United States)

    Daidzic, N. E.; Schmidt, E.; Hasan, M. M.; Altobelli, S.

    2004-01-01

    We used a permanent-magnet MRI system to estimate the integral and spatially- and/or temporally-resolved void-fraction distributions and flow patterns in gas-liquid two-phase flows. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. Air flow rates were varied between 1 and 200 ml/min. The cylindrical non-conducting test tube in which two-phase flow was measured was placed in a 2.67 kGauss MRI with MRT spectrometer/imager. Roughly linear relationship has been obtained for the integral void-fraction, obtained by volume-averaging of the spatially-resolved signals, and the air flow rate in upward direction. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI a non-invasive and non-intrusive experimental technique can indeed provide a wealth of different qualitative and quantitative data and is especially well suited for averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows.

  1. Position and width of normal adult optic chiasm as measured in coronal MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Soon; Park, Jin Sook [Wonju College of Medicine, Yonsei University, Wonju (Korea, Republic of)

    1994-06-15

    To evaluate the position and transverse dimension of the adult optic chiasm in normal Korean adult. The authors analysed 3D coronal volume images (TR/TE=30/13, flip angle=30 .deg. ) of 136 normal adult subjects without known visual abnormality. All MRI examinations were performed using a 0.5T system. MRI was reviewed retrospectively to determine the position (horizontal and tilted) of the potic chiosm and the transverse dimension of the optic chiasm was measured. Seventy- five (55%) of the 136 normal subjects had horizontal position, and sixty-one (45%) had tilted position. Thirty- eight (62%) of 61 with tilted position showed higher position on the right side, and twenty-three (38%) showed higher position on the side. The average transverse dimension(mean SD) was 15.2 {+-} 0.7mm in men and 14.6 {+-} 1.0mm in women. The difference of transverse dimension between men and women was statistically significant. Tilted position of the adult optic chiasm on coronal MRI was seen in approximately half of normal adults. The average of transverse dimension of normal optic chiasm was 15mm.

  2. Measurement of Strain in the Left Ventricle during Diastole withcine-MRI and Deformable Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Veress, Alexander I.; Gullberg, Grant T.; Weiss, Jeffrey A.

    2005-07-20

    The assessment of regional heart wall motion (local strain) can localize ischemic myocardial disease, evaluate myocardial viability and identify impaired cardiac function due to hypertrophic or dilated cardiomyopathies. The objectives of this research were to develop and validate a technique known as Hyperelastic Warping for the measurement of local strains in the left ventricle from clinical cine-MRI image datasets. The technique uses differences in image intensities between template (reference) and target (loaded) image datasets to generate a body force that deforms a finite element (FE) representation of the template so that it registers with the target image. To validate the technique, MRI image datasets representing two deformation states of a left ventricle were created such that the deformation map between the states represented in the images was known. A beginning diastoliccine-MRI image dataset from a normal human subject was defined as the template. A second image dataset (target) was created by mapping the template image using the deformation results obtained from a forward FE model of diastolic filling. Fiber stretch and strain predictions from Hyperelastic Warping showed good agreement with those of the forward solution. The technique had low sensitivity to changes in material parameters, with the exception of changes in bulk modulus of the material. The use of an isotropic hyperelastic constitutive model in the Warping analyses degraded the predictions of fiber stretch. Results were unaffected by simulated noise down to an SNR of 4.0. This study demonstrates that Warping in conjunction with cine-MRI imaging can be used to determine local ventricular strains during diastole.

  3. Cerebral blood flow measurement using fMRI and PET: a cross-validation study.

    Science.gov (United States)

    Chen, Jean J; Wieckowska, Marguerite; Meyer, Ernst; Pike, G Bruce

    2008-01-01

    An important aspect of functional magnetic resonance imaging (fMRI) is the study of brain hemodynamics, and MR arterial spin labeling (ASL) perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF) measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (DeltaCBF) measured using a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion method to those obtained using H(2) (15)O PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI) masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average DeltaCBF of 21.5 +/- 8.2% for FAIR versus 28.2 +/- 12.8% for PET at maximum stimulation intensity). Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL DeltaCBF for all 3 ROI types indicated no significant difference from unity (P > .05).

  4. Cerebral Blood Flow Measurement Using fMRI and PET: A Cross-Validation Study

    Directory of Open Access Journals (Sweden)

    Jean J. Chen

    2008-01-01

    Full Text Available An important aspect of functional magnetic resonance imaging (fMRI is the study of brain hemodynamics, and MR arterial spin labeling (ASL perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (ΔCBF measured using a flow-sensitive alternating inversion recovery (FAIR ASL perfusion method to those obtained using H2O15 PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (average ΔCBF of 21.5±8.2% for FAIR versus 28.2±12.8% for PET at maximum stimulation intensity. Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, a t-test comparison of the slopes of the linear fits of PET versus ASL ΔCBF for all 3 ROI types indicated no significant difference from unity (P>.05.

  5. Cell Treatment for Stroke in Type Two Diabetic Rats Improves Vascular Permeability Measured by MRI.

    Directory of Open Access Journals (Sweden)

    Guangliang Ding

    Full Text Available Treatment of stroke with bone marrow stromal cells (BMSC significantly enhances brain remodeling and improves neurological function in non-diabetic stroke rats. Diabetes is a major risk factor for stroke and induces neurovascular changes which may impact stroke therapy. Thus, it is necessary to test our hypothesis that the treatment of stroke with BMSC has therapeutic efficacy in the most common form of diabetes, type 2 diabetes mellitus (T2DM. T2DM was induced in adult male Wistar rats by administration of a high fat diet in combination with a single intraperitoneal injection (35mg/kg of streptozotocin. These rats were then subjected to 2h of middle cerebral artery occlusion (MCAo. T2DM rats received BMSC (5x106, n = 8 or an equal volume of phosphate-buffered saline (PBS (n = 8 via tail-vein injection at 3 days after MCAo. MRI was performed one day and then weekly for 5 weeks post MCAo for all rats. Compared with vehicle treated control T2DM rats, BMSC treatment of stroke in T2DM rats significantly (p<0.05 decreased blood-brain barrier disruption starting at 1 week post stroke measured using contrast enhanced T1-weighted imaging with gadopentetate, and reduced cerebral hemorrhagic spots starting at 3 weeks post stroke measured using susceptibility weighted imaging, although BMSC treatment did not reduce the ischemic lesion volumes as demarcated by T2 maps. These MRI measurements were consistent with histological data. Thus, BMSC treatment of stroke in T2DM rats initiated at 3 days after stroke significantly reduced ischemic vascular damage, although BMSC treatment did not change infarction volume in T2DM rats, measured by MRI.

  6. Error analysis of cine phase contrast MRI velocity measurements used for strain calculation.

    Science.gov (United States)

    Jensen, Elisabeth R; Morrow, Duane A; Felmlee, Joel P; Odegard, Gregory M; Kaufman, Kenton R

    2015-01-02

    Cine Phase Contrast (CPC) MRI offers unique insight into localized skeletal muscle behavior by providing the ability to quantify muscle strain distribution during cyclic motion. Muscle strain is obtained by temporally integrating and spatially differentiating CPC-encoded velocity. The aim of this study was to quantify CPC measurement accuracy and precision and to describe error propagation into displacement and strain. Using an MRI-compatible jig to move a B-gel phantom within a 1.5 T MRI bore, CPC-encoded velocities were collected. The three orthogonal encoding gradients (through plane, frequency, and phase) were evaluated independently in post-processing. Two systematic error types were corrected: eddy current-induced bias and calibration-type error. Measurement accuracy and precision were quantified before and after removal of systematic error. Through plane- and frequency-encoded data accuracy were within 0.4 mm/s after removal of systematic error - a 70% improvement over the raw data. Corrected phase-encoded data accuracy was within 1.3 mm/s. Measured random error was between 1 to 1.4 mm/s, which followed the theoretical prediction. Propagation of random measurement error into displacement and strain was found to depend on the number of tracked time segments, time segment duration, mesh size, and dimensional order. To verify this, theoretical predictions were compared to experimentally calculated displacement and strain error. For the parameters tested, experimental and theoretical results aligned well. Random strain error approximately halved with a two-fold mesh size increase, as predicted. Displacement and strain accuracy were within 2.6 mm and 3.3%, respectively. These results can be used to predict the accuracy and precision of displacement and strain in user-specific applications.

  7. Reference values of MRI measurements of the common bile duct and pancreatic duct in children

    Energy Technology Data Exchange (ETDEWEB)

    Gwal, Kriti; Bedoya, Maria A.; Patel, Neal; Darge, Kassa; Anupindi, Sudha A. [University of Pennsylvania Perelman School of Medicine, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Rambhatla, Siri J. [Beth Israel Medical Center, Department of Pediatrics, Newark, NJ (United States); Sreedharan, Ram R. [University of Pennsylvania, Departments of Gastroenterology, Hepatology and Nutrition, The Children' s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA (United States)

    2015-08-15

    Magnetic resonance imaging/cholangiopancreatography (MRI/MRCP) is now an essential imaging modality for the evaluation of biliary and pancreatic pathology in children, but there are no data depicting the normal diameters of the common bile duct (CBD) and pancreatic duct. Recognition of abnormal duct size is important and the increasing use of MRCP necessitates normal MRI measurements. To present normal MRI measurements for the common bile duct and pancreatic duct in children. In this retrospective study we searched all children ages birth to 10 years in our MR urography (MRU) database from 2006 until 2013. We excluded children with a history of hepatobiliary or pancreatic surgery. We stratified 204 children into five age groups and retrospectively measured the CBD and the pancreatic duct on 2-D axial and 3-D coronal T2-weighted sequences. We performed statistical analysis, using logistic and linear regressions to detect the age association of the visibility and size of the duct measurements. We used non-parametric tests to detect gender and imaging plane differences. Our study included 204 children, 106 (52%) boys and 98 (48%) girls, with a median age of 33 months (range 0-119 months). The children were distributed into five age groups. The common bile duct was visible in all children in all age groups. The pancreatic duct was significantly less visible in the youngest children, group 1 (54/67, 80.5%; P = 0.003) than in the oldest children, group 5 (22/22, 100%). In group 2 the pancreatic duct was seen in 19/21 (90.4%), in group 3 52/55 (94.5%), and in group 4 39/39 (100%). All duct measurements increased with age (P < 0.001; r-value > 0.423), and the incremental differences between ages were significant. The measurement variations between the axial and coronal planes were statistically significant (P < 0.001); however these differences were fractions of millimeters. For example, in group 1 the mean coronal measurement of the CBD was 2.1 mm and the axial

  8. MRI measurement of blood-brain barrier transport with a rapid acquisition refocused echo (RARE) method

    Science.gov (United States)

    Walton, Jeffrey H; Ng, Kit Fai; Anderson, Steven E; Rutledge, John C

    2015-01-01

    Dynamic Contrast Enhanced (DCE) MRI is increasingly being used to assess changes in capillary permeability. Most quantitative techniques used to measure capillary permeability are based on the Fick equation that requires measurement of signal reflecting both plasma and tissue concentrations of the solute being tested. To date, most Magnetic Resonance Imaging (MRI) methods for acquiring appropriate data quickly rely on gradient recalled echo (GRE) type acquisitions, which work well in clinical low field settings. However, acquiring this type of data on high field small animal preclinical MRIs is problematic due to geometrical distortions from susceptibility mismatch. This problem can be exacerbated when using small animal models to measure blood brain barrier (BBB) permeability, where precise sampling from the superior sagittal sinus (SSS) is commonly used to determine the plasma concentration of the contrast agent. Here we present results demonstrating that a standard saturation recovery rapid acquisition refocused echo (RARE) method is capable of acquiring T1 maps with good spatial and temporal resolution for Patlak analysis (Patlak, 1983) to assess changes in BBB Gd-DTPA permeability following middle cerebral artery occlusion with reperfusion in the rat. This method limits known problems with magnetic susceptibility mismatch and may thus allow greater accuracy in BBB permeability measurement in small animals. PMID:25998382

  9. Interdependence and contributions of sun exposure and vitamin D to MRI measures in multiple sclerosis.

    Science.gov (United States)

    Zivadinov, Robert; Treu, Cierra N; Weinstock-Guttman, Bianca; Turner, Caitlin; Bergsland, Niels; O'Connor, Kerri; Dwyer, Michael G; Carl, Ellen; Ramasamy, Deepa P; Qu, Jun; Ramanathan, Murali

    2013-10-01

    To assess the relationships of sun exposure history, supplementation and environmental factors to vitamin D levels in multiple sclerosis (MS) patients and to evaluate the associations between sun exposure and MRI measures. This study included 264 MS patients (mean age 46.9±10 years, disease duration 14.6±10 years; 67.8% relapsing-remitting, 28% secondary progressive and 4.2% primary progressive MS) and 69 healthy controls. Subjects underwent neurological and 3 T MRI examinations, provided blood samples and answered questions to a structured questionnaire. Information on race, skin and eye colour, supplement use, body mass index (BMI) and sun exposure was obtained by questionnaire. The vitamin D metabolites (25-hydroxy vitamin D3, 1, 25-dihydroxy vitamin D3 and 24, 25-dihydroxy vitamin D3) were measured using mass spectrometry. Multivitamin supplementation (partial correlation r(p)=0.29, psun exposure (r(p)=0.22, p=0.002) and darker eye colour (r(p)=-0.18, p=0.015) had the strongest associations with vitamin D metabolite levels in the MS group. Increased summer sun exposure was associated with increased grey matter volume (GMV, r(p)=0.16, p=0.019) and whole brain volume (WBV, r(p)=0.20, p=0.004) after correcting for Extended Disability Status Scale in the MS group. Inclusion of 25-hydroxy vitamin D3 levels did not substantially affect the positive associations of sun exposure with WBV (r(p)=0.18, p=0.003) and GMV (r(p)=0.14, p=0.026) in the MS group. Sun exposure may have direct effects on MRI measures of neurodegeneration in MS, independently of vitamin D.

  10. Volume measurement by using super-resolution MRI: application to prostate volumetry

    CERN Document Server

    Oubel, Estanislao; Iannessi, Antoine

    2015-01-01

    Accuracy and precision of measurements are important for patient follow up in oncology but, unfortunately, partial volume effects introduce an undesired variability between observers. Super resolution techniques (SR) combine multiple acquisitions of an object into a single image richer in details. Herein, the use of SR for reducing variability is investigated in the specific context of prostate measurements. Prostate is typically imaged by T2-weighted MRI in three perpendicular low resolution images, each of them presenting partial volume effects in the direction of the slice selection gradient. SR techniques allow to combine these images into an image presenting the same level of details in all directions. This is expected to increase the accuracy and reproducibility of volume measurements, which in turn improves other derived measurements like PSA density.

  11. Sub-band denoising and spline curve fitting method for hemodynamic measurement in perfusion MRI

    Science.gov (United States)

    Lin, Hong-Dun; Huang, Hsiao-Ling; Hsu, Yuan-Yu; Chen, Chi-Chen; Chen, Ing-Yi; Wu, Liang-Chi; Liu, Ren-Shyan; Lin, Kang-Ping

    2003-05-01

    In clinical research, non-invasive MR perfusion imaging is capable of investigating brain perfusion phenomenon via various hemodynamic measurements, such as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean trasnit time (MTT). These hemodynamic parameters are useful in diagnosing brain disorders such as stroke, infarction and periinfarct ischemia by further semi-quantitative analysis. However, the accuracy of quantitative analysis is usually affected by poor signal-to-noise ratio image quality. In this paper, we propose a hemodynamic measurement method based upon sub-band denoising and spline curve fitting processes to improve image quality for better hemodynamic quantitative analysis results. Ten sets of perfusion MRI data and corresponding PET images were used to validate the performance. For quantitative comparison, we evaluate gray/white matter CBF ratio. As a result, the hemodynamic semi-quantitative analysis result of mean gray to white matter CBF ratio is 2.10 +/- 0.34. The evaluated ratio of brain tissues in perfusion MRI is comparable to PET technique is less than 1-% difference in average. Furthermore, the method features excellent noise reduction and boundary preserving in image processing, and short hemodynamic measurement time.

  12. Tissue temperature distribution measurement by MRI and laser immunology for cancer treatment

    Science.gov (United States)

    Chen, Yichao; Gnyawali, Surya C.; Wu, Feng; Liu, Hong; Tesiram, Yasvir A.; Abbott, Andrew; Towner, Rheal A.; Chen, Wei R.

    2007-02-01

    In cancer treatment and immune response enhancement research, Magnetic Resonance Imaging (MRI) is an ideal method for non-invasive, three-dimensional temperature measurement. We used a 7.1-Tesla magnetic resonance imager for ex vivo tissues and small animal to determine temperature distribution of target tissue during laser irradiation. The feasibility of imaging is approved with high spatial resolution and high signal-noise- ratio. Tissue-simulating gel phantom gel, biological tissues, and tumor-bearing animals were used in the experiments for laser treatment and MR imaging. Thermal couple measurement of temperature in target samples was used for system calibration. An 805-nm laser was used to irradiate the samples with a laser power in the range of 1 to 2.5 watts. Using the MRI system and a specially developed processing algorithm, a clear temperature distribution matrix in the target tissue and surrounding tissue was obtained. The temperature profiles show that the selective laser photothermal effect could result in tissue temperature elevation in a range of 10 to 45 °C. The temperature resolution of the measurement was about 0.37°C including the total system error. The spatial resolution was 0.4 mm (128x128 pixels with field of view of 5.5x5.5 cm). The temperature distribution provided in vivo thermal information and future reference for optimizing dye concentration and irradiation parameters to achieve optimal thermal effects in cancer treatment.

  13. Carboxylated magnetic nanoparticles as MRI contrast agents: Relaxation measurements at different field strengths

    Energy Technology Data Exchange (ETDEWEB)

    Jedlovszky-Hajdu, Angela, E-mail: angela.hajdu@net.sote.hu [Laboratory of Nanochemistry, Department of Biophysics and Radiation Biology, Semmelweis University, Nagyvarad Sq 4, H-1089 Budapest (Hungary); Tombacz, Etelka, E-mail: tombacz@chem.u-szeged.hu [Department of Physical Chemistry and Material Science, University of Szeged, Aradi Vt. Sq 1, Szeged 6720 (Hungary); Banyai, Istvan, E-mail: banyai.istvan@science.unideb.hu [Department of Colloid and Environmental Chemistry, University of Debrecen (Hungary); Babos, Magor, E-mail: babosmagor@yahoo.com [Euromedic Diagnostics Szeged Ltd., Semmelweis St 6, Szeged 6720 (Hungary); Palko, Andras, E-mail: palko@radio.szote.u-szeged.hu [Faculty of Medicine, Department of Radiology, University of Szeged (Hungary)

    2012-09-15

    At the moment the biomedical applications of magnetic fluids are the subject of intensive scientific interest. In the present work, magnetite nanoparticles (MNPs) were synthesized and stabilized in aqueous medium with different carboxylic compounds (citric acid (CA), polyacrylic acid (PAA), and sodium oleate (NaOA)), in order to prepare well stabilized magnetic fluids (MFs). The magnetic nanoparticles can be used in the magnetic resonance imaging (MRI) as contrast agents. Magnetic resonance relaxation measurements of the above MFs were performed at different field strengths (i.e., 0.47, 1.5 and 9.4 T) to reveal the field strength dependence of their magnetic responses, and to compare them with that of ferucarbotran, a well-known superparamagnetic contrast agent. The measurements showed characteristic differences between the tested magnetic fluids stabilized by carboxylic compounds and ferucarbotran. It is worthy of note that our magnetic fluids have the highest r2 relaxivities at the field strength of 1.5 T, where the most of the MRI works in worldwide. - Highlights: Black-Right-Pointing-Pointer Magnetic resonance relaxation measurements were done at different field strengths. Black-Right-Pointing-Pointer Results show characteristic differences between the tested carboxylated MFs. Black-Right-Pointing-Pointer r1 and r2 relaxivities depend on the thickness of the protecting layer. Black-Right-Pointing-Pointer MFs have high r2/r1 ratios at each magnetic field.

  14. MRI of the Chest

    Medline Plus

    Full Text Available ... distinguish between cancer tissue and fluid, known as edema . MRI typically costs more and may take more ... with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes ...

  15. Right-sided cardiac function in healthy volunteers measured by first-pass radionuclide ventriculography and gated blood-pool SPECT: comparison with cine MRI

    DEFF Research Database (Denmark)

    Kjaer, Andreas; Lebech, Anne-Mette; Hesse, Birger

    2005-01-01

    and breath-hold cine MRI performed according to standard protocols. RESULTS: Normal ranges for RV ejection fraction (RVEF) defined as mean +/- 2SD were 0.49-0.72, 0.44-0.66 and 0.40-0.69 when measured by MRI, FP and GBPS respectively. Bland-Altman analysis showed a mean difference (bias) between MRI and FP...

  16. Validation of Continuously Tagged MRI for the Measurement of Dynamic 3D Skeletal Muscle Tissue Deformation

    CERN Document Server

    Moerman, Kevin M; Simms, Ciaran K; Lamerichs, Rolf M; Stoker, Jaap; Nederveen, Aart J

    2016-01-01

    A SPAMM tagged MRI methodology is presented allowing continuous (3.3-3.6 Hz) sampling of 3D dynamic soft tissue deformation using non-segmented 3D acquisitions. The 3D deformation is reconstructed by the combination of 3 mutually orthogonal tagging directions, thus requiring only 3 repeated motion cycles. In addition a fully automatic post-processing framework is presented employing Gabor scale-space and filter-bank analysis for tag extrema segmentation and triangulated surface fitting aided by Gabor filter bank derived surface normals. Deformation is derived following tracking of tag surface triplet triangle intersections. The dynamic deformation measurements were validated using indentation tests (~20 mm deep at 12 mm/s) on a silicone gel soft tissue phantom containing contrasting markers which provide a reference measure of deformation. In addition, the techniques were evaluated in-vivo for dynamic skeletal muscle tissue deformation measurement during indentation of the biceps region of the upper arm in a ...

  17. 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.)

  18. Fetal lung volume measurement by MRI with high-speed imaging systems

    Energy Technology Data Exchange (ETDEWEB)

    Osada, Hisao; Kaku, Kenshi [Chiba Univ. (Japan). Hospital

    2002-08-01

    Although ultrasonography is widely used for fetal morphologic observation, magnetic resonance imaging (MRI) has gained popularity as a new prenatal diagnostic method with recent introduction of high-speed imaging systems. Infants with lung hypoplasia affecting respiratory function require intensive management starting immediately after birth. Therefore, accurate prenatal differential diagnosis and severity evaluation are extremely important for these fetuses. The aim of this study is to measure fetal lung volume using a computer-based, three-dimensional MRI imaging system and to evaluate the possibility of clinical applications of this procedure. A total of 96 fetuses were evaluated, all were morphologically abnormal, and MRI was done for advanced assessment from 24 to 39 weeks gestation. Three-directional views of fetal chest were imaged by Signa Horizon, 1.5 Tesla, version 5.6 (General Electronics) with the following conditions; coil: TORSO coil, sequence: SSFSE (single shot fast spin echo), slice thickness: 5 mm, and imaging speed: 2 seconds/slice. To calculate the lung volume and create three-dimensional image, the lung area in each slice was traced out, then multiplied using computer image processing. Simultaneously, the volumes of all slices were summed to give the volume of each lung. Linear regression analysis and analysis of covariance (ANCOVA) were used for statistical analyses. In all cases, clear images were obtained, and were adequate for three-dimensional evaluation of the fetal lung. Thirty-five fetuses had poor outcomes, such as intrauterine fetal death, neonatal death, and intensive respiratory care. Regression lines of lung volume versus gestational week were calculated for these fetuses with poor outcome and 61 other fetuses with good outcome. ANCOVA, with gestational week as a covariant, revealed a significant intergroup difference in the lung volume (p<0.001). Similarly, regression lines of lung volume versus fetal body weight estimated by

  19. Accurate perioperative flow measurement of the portal vein and hepatic and renal artery: A role for preoperative MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, Mechteld A.R., E-mail: mar.vermeulen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Ligthart-Melis, Gerdien C., E-mail: g.ligthart-melis@vumc.nl [Department of Internal Medicine, Dietetics and Nutritional Sciences, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Buijsman, René, E-mail: renebuysman@gmail.com [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Siroen, Michiel P.C., E-mail: m.siroen6@upcmail.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Poll, Marcel C.G. van de, E-mail: mcg.vandepoll@ah.unimaas.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Boelens, Petra G., E-mail: p.boelens@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Dejong, Cornelis H.C., E-mail: chc.dejong@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Schaik, Cors van, E-mail: c.vanschaik@vumc.nl [Department of Radiology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Hofman, Mark B.M., E-mail: mbm.hofman@vumc.nl [Department of Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Leeuwen, Paul A.M. van, E-mail: pam.vleeuwen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2012-09-15

    Background: Quantification of abdominal blood flow is essential for a variety of gastrointestinal and hepatic topics such as liver transplantation or metabolic flux measurement, but those need to be performed during surgery. It is not clear whether Duplex Doppler Ultrasound during surgery or MRI before surgery is the tool to choose. Objective: To examine whether preoperative evaluation of abdominal blood flow using MRI could prove to be a useful and reliable alternative for the perioperative sonographic approach. Methods: In this study portal and renal venous flow and hepatic arterial flow were sequentially quantified by preoperative MRI, preoperative and perioperative Duplex Doppler Ultrasound (DDUS). 55 Patients scheduled for major abdominal surgery were studied and methods and settings were compared. Additionally, average patient population values were compared. Results: Mean (±SD) plasmaflow measured by perioperative DDUS, preoperative DDUS and MRI, respectively was 433 ± 200/423 ± 162/507 ± 96 ml/min (portal vein); 96 ± 70/74 ± 41/108 ± 91 ml/min (hepatic artery); 248 ± 139/201 ± 118/219 ± 69 ml/min (renal vein). No differences between the different settings of DDUS measurement were detected. Equality of mean was observed for all measurements. Bland Altman Plots showed widespread margins. Hepatic arterial flow measurements correlated with each other, but portal and renal venous flow correlations were absent. Conclusions: Surgery and method (DDUS vs. MRI) do not affect mean flow values. Individual comparison is restricted due to wide range in measurements. Since MRI proves to be more reliable with respect to inter-observer variability, we recommend using mean MRI results in experimental setups.

  20. Comparing deflection measurements of a magnetically steerable catheter using optical imaging and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lillaney, Prasheel, E-mail: Prasheel.Lillaney@ucsf.edu; Caton, Curtis; Martin, Alastair J.; Losey, Aaron D.; Evans, Leland; Saeed, Maythem; Cooke, Daniel L.; Wilson, Mark W.; Hetts, Steven W. [Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California 94143 (United States)

    2014-02-15

    Purpose: Magnetic resonance imaging (MRI) is an emerging modality for interventional radiology, giving clinicians another tool for minimally invasive image-guided interventional procedures. Difficulties associated with endovascular catheter navigation using MRI guidance led to the development of a magnetically steerable catheter. The focus of this study was to mechanically characterize deflections of two different prototypes of the magnetically steerable catheterin vitro to better understand their efficacy. Methods: A mathematical model for deflection of the magnetically steerable catheter is formulated based on the principle that at equilibrium the mechanical and magnetic torques are equal to each other. Furthermore, two different image based methods for empirically measuring the catheter deflection angle are presented. The first, referred to as the absolute tip method, measures the angle of the line that is tangential to the catheter tip. The second, referred to the base to tip method, is an approximation that is used when it is not possible to measure the angle of the tangent line. Optical images of the catheter deflection are analyzed using the absolute tip method to quantitatively validate the predicted deflections from the mathematical model. Optical images of the catheter deflection are also analyzed using the base to tip method to quantitatively determine the differences between the absolute tip and base to tip methods. Finally, the optical images are compared to MR images using the base to tip method to determine the accuracy of measuring the catheter deflection using MR. Results: The optical catheter deflection angles measured for both catheter prototypes using the absolute tip method fit very well to the mathematical model (R{sup 2} = 0.91 and 0.86 for each prototype, respectively). It was found that the angles measured using the base to tip method were consistently smaller than those measured using the absolute tip method. The deflection angles measured

  1. Turbulent Kinetic Energy Measurement Using Phase Contrast MRI for Estimating the Post-Stenotic Pressure Drop: In Vitro Validation and Clinical Application.

    Science.gov (United States)

    Ha, Hojin; Kim, Guk Bae; Kweon, Jihoon; Huh, Hyung Kyu; Lee, Sang Joon; Koo, Hyun Jung; Kang, Joon-Won; Lim, Tae-Hwan; Kim, Dae-Hee; Kim, Young-Hak; Kim, Namkug; Yang, Dong Hyun

    2016-01-01

    Although the measurement of turbulence kinetic energy (TKE) by using magnetic resonance imaging (MRI) has been introduced as an alternative index for quantifying energy loss through the cardiac valve, experimental verification and clinical application of this parameter are still required. The goal of this study is to verify MRI measurements of TKE by using a phantom stenosis with particle image velocimetry (PIV) as the reference standard. In addition, the feasibility of measuring TKE with MRI is explored. MRI measurements of TKE through a phantom stenosis was performed by using clinical 3T MRI scanner. The MRI measurements were verified experimentally by using PIV as the reference standard. In vivo application of MRI-driven TKE was explored in seven patients with aortic valve disease and one healthy volunteer. Transvalvular gradients measured by MRI and echocardiography were compared. MRI and PIV measurements of TKE are consistent for turbulent flow (0.666 400). The turbulence pressure drop correlates strongly with total TKE (R2 = 0.986). However, in vivo measurements of TKE are not consistent with the transvalvular pressure gradient estimated by echocardiography. These results suggest that TKE measurement via MRI may provide a potential benefit as an energy-loss index to characterize blood flow through the aortic valve. However, further clinical studies are necessary to reach definitive conclusions regarding this technique.

  2. MRI measurement on intercondylar notch after anterior cruciate ligament rupture and its correlation.

    Science.gov (United States)

    Ouyang, Xiao; Wang, Yu Hao; Wang, Jian; Hong, Shi Dong; Xin, Feng; Wang, Lin; Yang, Xiao Wei; Wang, Jing Rong; Wang, Li Ming; Wei, B O; Wang, Qing; Cui, Wei Ding; Fu, Xing Li

    2016-04-01

    The knee joint is extremely susceptible to injury, which is usually identified by magnetic resonance imaging (MRI). In the present study, MRI was applied to quantitatively detect the association between anterior cruciate ligament (ACL) rupture and anatomic morphologic changes of the intercondylar notch. Forty patients with unilateral ACL rupture who were treated between July, 2013 and October, 2014 were enrolled in the present study. The patients were divided into the observation (affected side) and control (healthy side) groups. MRI measurements were undertaken based on parameters associated with intercondylar notch of double knee joints. The results showed that intercondylar notch width (ICW) in the observation group was significantly smaller than that in the control group, and differences were statistically significant (Pnotch height and femoral condyle width [epicondylar width (EW)] between the two groups were not statistically significant (P>0.05). Notch width index (NWI) and notch shape index (NSI) in the observation group were significantly less than those in the control group and differences were statistically significant (P0.05). The differential value of ICW in the observation group was 2.6±1.3 mm and the ACL rupture time of the affected knee was 20.4±1.3 months on average. The correlation was statistically significant (Pnotch stenosis degree on the affected knee was not statistically significant (P>0.05). In conclusion, after ACL rupture, ICW on the affected knee had significant stenosis, NSI and NWI were significantly reduced and the stenosis degree was aggravated with the prolongation of course. By contrast, Lysholm and Tegner scoring of patients with different degrees of stenosis had no correlation.

  3. SU-E-J-120: Comparing 4D CT Computed Ventilation to Lung Function Measured with Hyperpolarized Xenon-129 MRI

    Energy Technology Data Exchange (ETDEWEB)

    Neal, B; Chen, Q [University of Virginia, Charlottesville, VA (United States)

    2015-06-15

    Purpose: To correlate ventilation parameters computed from 4D CT to ventilation, profusion, and gas exchange measured with hyperpolarized Xenon-129 MRI for a set of lung cancer patients. Methods: Hyperpolarized Xe-129 MRI lung scans were acquired for lung cancer patients, before and after radiation therapy, measuring ventilation, perfusion, and gas exchange. In the standard clinical workflow, these patients also received 4D CT scans before treatment. Ventilation was computed from 4D CT using deformable image registration (DIR). All phases of the 4D CT scan were registered using a B-spline deformable registration. Ventilation at the voxel level was then computed for each phase based on a Jacobian volume expansion metric, yielding phase sorted ventilation images. Ventilation based upon 4D CT and Xe-129 MRI were co-registered, allowing qualitative visual comparison and qualitative comparison via the Pearson correlation coefficient. Results: Analysis shows a weak correlation between hyperpolarized Xe-129 MRI and 4D CT DIR ventilation, with a Pearson correlation coefficient of 0.17 to 0.22. Further work will refine the DIR parameters to optimize the correlation. The weak correlation could be due to the limitations of 4D CT, registration algorithms, or the Xe-129 MRI imaging. Continued development will refine parameters to optimize correlation. Conclusion: Current analysis yields a minimal correlation between 4D CT DIR and Xe-129 MRI ventilation. Funding provided by the 2014 George Amorino Pilot Grant in Radiation Oncology at the University of Virginia.

  4. Dynamic measurements of total hepatic blood flow with Phase Contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yzet, Thierry [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Yzet.Thierry@chu-amiens.fr; Bouzerar, Roger [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: bouzerar.roger@chu-amiens.fr; Baledent, Olivier [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Olivier.Baledent@chu-amiens.fr; Renard, Cedric [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Renard.Cedric@chu-amiens.fr; Lumbala, Didier Mbayo [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: MbayoLumbala.Didier@chu-amiens.fr; Nguyen-Khac, Eric [Mobile Unit of Alcoology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Nguyen-Khac.Eric@chu-amiens.fr; Regimbeau, Jean-Marc [Department of Visceral and Digestive General Surgery, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: regimbeau.jean-marc@chu-amiens.fr; Deramond, H. [Department of Radiology, University Hospital, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: deramond.herve@chu-amiens.fr; Meyer, Marc-Etienne [Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Place Victor Pauchet, 80054 Amiens cedex 1 (France)], E-mail: Meyer.Marc-Etienne@chu-amiens.fr

    2010-01-15

    Background/Aims: To measure total hepatic blood flow including portal and proper hepatic artery flows as well as the temporal evolution of the vessel's section during a cardiac cycle. Methods: Twenty healthy subjects, with a mean age of 26 years, were explored. Magnetic resonance imaging blood flow measurements were carried out in the portal vein and the proper hepatic artery. MR studies were performed using a 1.5T imager (General Electric Medical Systems). Gradient-echo 2D Fast Cine Phase Contrast sequences were used with both cardiac and respiratory gatings. Data analysis was performed using a semi-automatic software built in our laboratory. Results: The total hepatic flow rate measured was 1.35 {+-} 0.18 L/min or 19.7 {+-} 4.6 mL/(min kg). The proper hepatic artery provided 19.1% of the total hepatic blood flow entering the liver. Those measurements were in agreement with earlier studies using direct measurements. Mean and maximum velocities were also assessed and a discrepancy between our values and the literature's Doppler data was found. Measurements of the portal vein area have shown a mean variation, defined as a 'pulsatility' index of 18% over a cardiac cycle. Conclusions: We report here proper hepatic artery blood flow rate measurements using MRI. Associated with portal flow measurements, we have shown the feasibility of total hepatic flowmetry using a non-invasive and harmless technique.

  5. Registration pipeline for pulmonary free-breathing 1H MRI ventilation measurements

    Science.gov (United States)

    Guo, Fumin; Capaldi, Dante P. I.; Di Cesare, Robert; Fenster, Aaron; Parraga, Grace

    2017-03-01

    Objectives: Our aim was to develop a clinically-practical and physiologically-relevant approach for regional structure-function measurements of the lung using Fourier decomposition of free-breathing pulmonary magnetic resonance imaging (FDMRI). Methods: Ten patients with chronic obstructive pulmonary disease provided written informed consent to a study protocol approved by Health Canada and completed pulmonary function tests, 1H/hyperpolarized noble gas and free-breathing pulmonary magnetic resonance imaging (MRI) during a single 2-hour visit. Free-breathing 1H MRI was simultaneously segmented using a multi-region coupled continuous max-flow approach by exploring primal/dual analysis and convex optimization techniques. The segmented free-breathing 1H MRI lung was registered using deformable registration approach that was developed using dual and convex optimization methods to compensate for respiratory/cardiac motion. Fourier decomposition of the co-registered lung was used to generate pulmonary functional information that was quantified as ventilation-defect-percent (VDP). The pipeline was implemented on a GPU for speed-up. Lung segmentation accuracy was measured by comparing algorithm and manual lung masks using Dice-similarity-coefficient (DSC). FD-VDP was compared to 3He-VDP using Pearson correlation coefficient and Bland-Altman analysis. The reproducibility of our algorithm was measured using coefficient of variation (CoV) and intraclass correlation coefficient (ICC) for DSC and FD-VDP. Results: The pipeline yielded a whole lung DSC of 95.7+/-1.7% and FD-VDP that were correlated with 3He-VDP (r = 0.81, p = 0.004). CoV (ICC) were 0.4% (0.98) and 4.1% (0.98) for whole lung DSC and FD-VDP, respectively. The proposed approach requires 45 min for parallel implementation with minimal user interaction. Conclusion: The proposed approach provides a clinically-practical pipeline to generate regional pulmonary structure-function measurements using free

  6. Measuring adult attachment representation in an fMRI environment: concepts and assessment.

    Science.gov (United States)

    Buchheim, Anna; George, Carol; Kachele, Horst; Erk, Susanne; Walter, Henrik

    2006-01-01

    Human attachment is defined as a biologically based behavioral system that influences motivational, cognitive, emotional, and memory processes with respect to intimate relationships (parents, life partner, own children). Recent neurobiological studies in this field have in common that they investigated social relationships by examining fMRI neuroimaging patterns while individuals viewed pictures of their beloved relationship partner versus friends, acquaintances, strangers, or mothers' responses to their young children. The researchers showed that the neural underpinnings of these unique intimate emotional states are linked to functionally specialized areas in the brain. Conceptualizing this work from a behavioral systems-attachment theory perspective, these studies did not directly address the subject's attachment representational system. Traditional attachment theory and research has been built on the analysis of attachment narratives, called 'attachment representation'. The Adult Attachment Projective developed by George and West in 2001 is a set of attachment-based schematic pictures. It is constructed to increasingly activate the participant's attachment system in the course of the task, that is, by the introduction of increasingly stressful attachment scenes concluding with pictures of individuals facing death and potential abuse alone. The attachment patterns are evaluated based on individuals' overall verbal response to the picture set. This paper proposes that the AAP is a fruitful measure to use in an fMRI environment to examine brain activation patterns in adults while they are speaking overtly about attachment stories in a standardized setting.

  7. Noninvasive measurement of liver iron concentration at MRI in children with acute leukemia: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Vag, Tibor; Krumbein, Ines; Reichenbach, Juergen R.; Lopatta, Eric; Stenzel, Martin; Kaiser, Werner A.; Mentzel, Hans-Joachim [Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Jena (Germany); Kentouche, Karim; Beck, James [Friedrich Schiller University Jena, Department of Pediatrics, Jena (Germany); Renz, Diane M. [Charite University Medicine Berlin, Department of Radiology, Campus Virchow Clinic, Berlin (Germany)

    2011-08-15

    Routine assessment of body iron load in patients with acute leukemia is usually done by serum ferritin (SF) assay; however, its sensitivity is impaired by different conditions including inflammation and malignancy. To estimate, using MRI, the extent of liver iron overload in children with acute leukemia and receiving blood transfusions, and to examine the association between the degree of hepatic iron overload and clinical parameters including SF and the transfusion iron load (TIL). A total of 25 MRI measurements of the liver were performed in 15 children with acute leukemia (mean age 9.75 years) using gradient-echo sequences. Signal intensity ratios between the liver and the vertebral muscle (L/M ratio) were calculated and compared with SF-levels. TIL was estimated from the cumulative blood volume received, assuming an amount of 200 mg iron per transfused red blood cell unit. Statistical analysis revealed good correlation between the L/M SI ratio and TIL (r = -0.67, P = 0.002, 95% confidence interval CI = -0.83 to -0.34) in patients with acute leukemia as well as between L/M SI ratio and SF (r = -0.76, P = 0.0003, 95% CI = -0.89 to -0.52). SF may reliably reflect liver iron stores as a routine marker in patients suffering from acute leukemia. (orig.)

  8. Correlation of auditory brain stem response and the MRI measurements in neuro-degenerative disorders

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, Hidekazu (Tokyo Women' s Medical Coll. (Japan))

    1989-06-01

    The purpose of this study is to elucidate correlations of several MRI measurements of the cranium and brain, functioning as a volume conductor, to the auditory brain stem response (ABR) in neuro-degenerative disorders. The subjects included forty-seven patients with spinocerebellar degeneration (SCD) and sixteen of amyotrophic lateral sclerosis (ALS). Statistically significant positive correlations were found between I-V and III-V interpeak latencies (IPLs) and the area of cranium and brain in the longitudinal section of SCD patients, and between I-III and III-V IPLs and the area in the longitudinal section of those with ALS. And, also there were statistically significant correlations between the amplitude of the V wave and the area of brain stem as well as that of the cranium in the longitudinal section of SCD patients, and between the amplitude of the V wave and the area of the cerebrum in the longitudinal section of ALS. In conclusion, in the ABR, the IPLs were prolonged and the amplitude of the V wave was decreased while the MRI size of the cranium and brain increased. When the ABR is applied to neuro-degenerative disorders, it might be important to consider not only the conduction of the auditory tracts in the brain stem, but also the correlations of the size of the cranium and brain which act as a volume conductor. (author).

  9. Comparison of lumbar spinal canal measurements on MRI and CT; Comparaison des mesures du canal lombaire en IRM et TDM

    Energy Technology Data Exchange (ETDEWEB)

    Malghem, J.; Willems, X.; Vande Berg, B.; Cosnard, G.; Lecouvet, F. [Cliniques Universitaires Saint Luc, Dept. d' Imagerie Medicale, Bruxelles (Belgium); Robert, A. [Ecole de Sante Publique, Faculte de Medecine, Unite d' Epidemiologie, Biostatistique et Methodes Operationnelles en Sante, Bruxelles (Belgium)

    2009-04-15

    Purpose. To compare AP diameter measurements of spinal canal and thecal sac on MM and CT. Materials and methods. The AP diameter of the spinal canal at L4 and thecal sac at L4-5 were measured on both MRI and CT performed on patients at less than one month interval. Measurements were obtained from axial CT images of the abdomen on CT and sagittal T1W (n=98 ) and T2W (n=78) MR images of the spine. The examinations were reviewed at more than 24 hours interval. Radiologists were blinded. Inter-observer agreement evaluation was performed prior to this study. Measurements were compared using a t test for paired variables. Results. For the spinal canal, mean measurements were 0.4 {+-} 1.5 mm inferior on CT compared to MRI. For the thecal sac, mean measurements were 0.1 {+-} 1.4 mm inferior on CT compared to MRI. Conclusion. Measurements on CT and MRI for lumbar spinal canal and thecal sac are fairly comparable, with mean measurement differences inferior to the degree of precision of the measurement technique itself. (authors)

  10. Measuring the representational space of music with fMRI: a case study with Sting.

    Science.gov (United States)

    Levitin, Daniel J; Grafton, Scott T

    2016-12-01

    Functional brain imaging has revealed much about the neuroanatomical substrates of higher cognition, including music, language, learning, and memory. The technique lends itself to studying of groups of individuals. In contrast, the nature of expert performance is typically studied through the examination of exceptional individuals using behavioral case studies and retrospective biography. Here, we combined fMRI and the study of an individual who is a world-class expert musician and composer in order to better understand the neural underpinnings of his music perception and cognition, in particular, his mental representations for music. We used state of the art multivoxel pattern analysis (MVPA) and representational dissimilarity analysis (RDA) in a fixed set of brain regions to test three exploratory hypotheses with the musician Sting: (1) Composing would recruit neutral structures that are both unique and distinguishable from other creative acts, such as composing prose or visual art; (2) listening and imagining music would recruit similar neural regions, indicating that musical memory shares anatomical substrates with music listening; (3) the MVPA and RDA results would help us to map the representational space for music, revealing which musical pieces and genres are perceived to be similar in the musician's mental models for music. Our hypotheses were confirmed. The act of composing, and even of imagining elements of the composed piece separately, such as melody and rhythm, activated a similar cluster of brain regions, and were distinct from prose and visual art. Listened and imagined music showed high similarity, and in addition, notable similarity/dissimilarity patterns emerged among the various pieces used as stimuli: Muzak and Top 100/Pop songs were far from all other musical styles in Mahalanobis distance (Euclidean representational space), whereas jazz, R&B, tango and rock were comparatively close. Closer inspection revealed principaled explanations for the

  11. Measuring neuroplasticity associated with cerebral palsy rehabilitation: An MRI based power analysis.

    Science.gov (United States)

    Reid, Lee B; Pagnozzi, Alex M; Fiori, Simona; Boyd, Roslyn N; Dowson, Nicholas; Rose, Stephen E

    2017-05-01

    Researchers in the field of child neurology are increasingly looking to supplement clinical trials of motor rehabilitation with neuroimaging in order to better understand the relationship between behavioural training, brain changes, and clinical improvements. Randomised controlled trials are typically accompanied by sample size calculations to detect clinical improvements but, despite the large cost of neuroimaging, not equivalent calculations for concurrently acquired imaging neuroimaging measures of changes in response to intervention. To aid in this regard, a power analysis was conducted for two measures of brain changes that may be indexed in a trial of rehabilitative therapy for cerebral palsy: cortical thickness of the impaired primary sensorimotor cortex, and fractional anisotropy of the impaired, delineated corticospinal tract. Power for measuring fractional anisotropy was assessed for both region-of-interest-seeded and fMRI-seeded diffusion tractography. Taking into account practical limitations, as well as data loss due to behavioural and image-processing issues, estimated required participant numbers were 101, 128 and 59 for cortical thickness, region-of-interest-based tractography, and fMRI-seeded tractography, respectively. These numbers are not adjusted for study attrition. Although these participant numbers may be out of reach of many trials, several options are available to improve statistical power, including careful preparation of participants for scanning using mock simulators, careful consideration of image processing options, and enrolment of as homogeneous a cohort as possible. This work suggests that smaller and moderate sized studies give genuine consideration to harmonising scanning protocols between groups to allow the pooling of data. Copyright © 2017 ISDN. All rights reserved.

  12. Tumor-to-breast volume ratio as measured on MRI: a possible predictor of breast-conserving surgery versus mastectomy.

    Science.gov (United States)

    Faermann, Renata; Sperber, Fani; Schneebaum, Schlomo; Barsuk, Daphna

    2014-02-01

    The surgical approach to breast cancer changed dramatically in the past 20 years. The surgical objective today is to remove the tumor, ensuring negative margins and good cosmetic results, and preserving the breast when possible. Magnetic resonance imaging of the breast has become an essential imaging tool prior to surgery, diagnosing additional tumors and assessing tumor extent. Tumor-to-breast volume ratio, an important predictor of breast conservation, can be measured with MRI and may change the surgical decision. To measure the tumor-to-breast volume ratio using MRI in order to assess whether there is a correlation between this ratio and the type of surgery selected (breast-conserving or mastectomy). The volumes of the tumor and the breast and the tumor-to-breast volume ratio were retrospectively calculated using preoperative breast MRI in 76 patients who underwent breast-conserving surgery or mastectomy. Breast-conserving surgery (lumpectomy) was performed in 64 patients and mastectomy in 12. The average tumor-to-breast volume ratio was 0.06 (6%) in the lumpectomy group and 0.30 (30%) in the mastectomy group (P < 0.0001). The tumor-to-breast volume ratio correlated with the type of surgery. As measured on MRI, this ratio is an accurate means of determining the type of surgery best suited for a given patient. It is recommended that MRI-determined tumor-to-breast volume ratio become part of the surgical planning protocol for patients diagnosed with breast cancer.

  13. Ultrasound and MRI measurements of joint cartilage in healthy children. A validation study

    DEFF Research Database (Denmark)

    Spannow, A H; Stenboeg, E; Jensen, Mogens Pfeiffer;

    2011-01-01

    Purpose: In juvenile idiopathic arthritis (JIA), proliferative changes in the synovium and synovial fluid accumulation are pathological findings responsible for damage to the cartilaginous tissue and periarticular bone, which are late radiographic findings in conventional radiography. Early...... detection of these joint changes would allow the clinicians to initiate relevant therapies as is essential for the long-term outcome of JIA. Ultrasonography (US) has shown great potential for this purpose but validation in a pediatric setting is needed. The objective of this study was to validate US.......5 millimeters. The coefficient of variation (CV) was found to be good (16 %) except for in the case of the wrist joint (20 %). Conclusion: We found a good level of agreement and no significant systematic joint size-related differences in cartilage thickness measurements between MRI and US. US appears...

  14. Utilizing MRI to measure the transcytolemmal water exchange rate for the rat brain

    Science.gov (United States)

    Quirk, James D.; Bretthorst, G. Larry; Neil, Jeffrey J.

    2001-05-01

    Understanding the exchange of water between the intra- and extracellular compartments of the brain is important both for understanding basic physiology and for the interpretation of numerous MRI results. However, due to experimental difficulties, this basic property has proven difficult to measure in vivo. In our experiments, we will track overall changes in the relaxation rate constant of water in the rat brain following the administration of gadoteridol, a relaxation agent, to the extracellular compartment. From these changes, we will utilize probability theory and Markov Chain Monte Carlo simulations to infer the compartment specific water exchange and relaxation rate constants. Due to the correlated nature of these parameters and our inability to independently observe them, intelligent model selection is critical. Through analysis of simulated data sets, we refine our choice of model and method of data collection to optimize applicability to the in vivo situation.

  15. Accuracy and variability of tumor burden measurement on multi-parametric MRI

    Science.gov (United States)

    Salarian, Mehrnoush; Gibson, Eli; Shahedi, Maysam; Gaed, Mena; Gómez, José A.; Moussa, Madeleine; Romagnoli, Cesare; Cool, Derek W.; Bastian-Jordan, Matthew; Chin, Joseph L.; Pautler, Stephen; Bauman, Glenn S.; Ward, Aaron D.

    2014-03-01

    Measurement of prostate tumour volume can inform prognosis and treatment selection, including an assessment of the suitability and feasibility of focal therapy, which can potentially spare patients the deleterious side effects of radical treatment. Prostate biopsy is the clinical standard for diagnosis but provides limited information regarding tumour volume due to sparse tissue sampling. A non-invasive means for accurate determination of tumour burden could be of clinical value and an important step toward reduction of overtreatment. Multi-parametric magnetic resonance imaging (MPMRI) is showing promise for prostate cancer diagnosis. However, the accuracy and inter-observer variability of prostate tumour volume estimation based on separate expert contouring of T2-weighted (T2W), dynamic contrastenhanced (DCE), and diffusion-weighted (DW) MRI sequences acquired using an endorectal coil at 3T is currently unknown. We investigated this question using a histologic reference standard based on a highly accurate MPMRIhistology image registration and a smooth interpolation of planimetric tumour measurements on histology. Our results showed that prostate tumour volumes estimated based on MPMRI consistently overestimated histological reference tumour volumes. The variability of tumour volume estimates across the different pulse sequences exceeded interobserver variability within any sequence. Tumour volume estimates on DCE MRI provided the lowest inter-observer variability and the highest correlation with histology tumour volumes, whereas the apparent diffusion coefficient (ADC) maps provided the lowest volume estimation error. If validated on a larger data set, the observed correlations could support the development of automated prostate tumour volume segmentation algorithms as well as correction schemes for tumour burden estimation on MPMRI.

  16. Quantification of MRI measured myocardial perfusion reserve in healthy humans: a comparison with positron emission tomography

    DEFF Research Database (Denmark)

    Fritz-Hansen, Thomas; Hove, Jens D; Kofoed, Klaus F

    2008-01-01

    PURPOSE: To validate a noninvasive quantitative MRI technique, the K(i) perfusion method, for myocardial perfusion in humans using (13)N-ammonia PET as a reference method. MATERIALS AND METHODS: Ten healthy males (64 +/- 8 years) were examined with combined PET and MRI perfusion imaging at rest...... and during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd-DTPA-enhanced MRI and (13)N-ammonia PET were fitted by a two-compartment perfusion model. RESULTS: Mean perfusion values (+/-SD) derived from the MRI...... as a quantitative marker for myocardial perfusion in healthy humans....

  17. Comparison of ASL and DCE MRI for the non-invasive measurement of renal blood flow: quantification and reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Cutajar, Marica; Hales, Patrick W.; Clark, Christopher A.; Gordon, Isky [UCL Institute of Child Health, Imaging and Biophysics Unit, London (United Kingdom); Thomas, David L. [UCL Institute of Neurology, Department of Brain Repair and Rehabilitation, London (United Kingdom); Banks, T. [Great Ormond Street Hospital, Department of Radiology, London (United Kingdom)

    2014-06-15

    To investigate the reproducibility of arterial spin labelling (ASL) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and quantitatively compare these techniques for the measurement of renal blood flow (RBF). Sixteen healthy volunteers were examined on two different occasions. ASL was performed using a multi-TI FAIR labelling scheme with a segmented 3D-GRASE imaging module. DCE MRI was performed using a 3D-FLASH pulse sequence. A Bland-Altman analysis was used to assess repeatability of each technique, and determine the degree of correspondence between the two methods. The overall mean cortical renal blood flow (RBF) of the ASL group was 263 ± 41 ml min{sup -1} [100 ml tissue]{sup -1}, and using DCE MRI was 287 ± 70 ml min{sup -1} [100 ml tissue]{sup -1}. The group coefficient of variation (CV{sub g}) was 18 % for ASL and 28 % for DCE-MRI. Repeatability studies showed that ASL was more reproducible than DCE with CV{sub g}s of 16 % and 25 % for ASL and DCE respectively. Bland-Altman analysis comparing the two techniques showed a good agreement. The repeated measures analysis shows that the ASL technique has better reproducibility than DCE-MRI. Difference analysis shows no significant difference between the RBF values of the two techniques. (orig.)

  18. A measurement method for distinguishing the real contact area of rough surfaces of transparent solids using improved Otsu technique

    Science.gov (United States)

    Song, Bao-Jiang; Yan, Shao-Ze; Xiang, Wu-Wei-Kai

    2015-01-01

    An experimental method of measuring the real contact area of transparent blocks based on the principle of total internal reflection is presented, intending to support the investigation of friction characteristics, heat conduction, and energy dissipation at the contact interface. A laser sheet illuminates the contact interface, and the transmitted laser sheet is projected onto a screen. Then the contact information is acquired from the screen by a camera. An improved Otsu method is proposed to process the data of experimental images. It can compute the threshold of the overall image and filter out all the pixels one by one. Through analyzing the experimental results, we describe the relationship between the real contact area and the positive pressure during a continuous loading process, at different loading rates, with the polymethyl methacrylate (PMMA) material. A hysteresis phenomenon in the relationship between the real contact area and the positive pressure is found and explained. Project supported by the National Natural Science Foundation of China (Grant No. 11272171), the Beijing Natural Science Foundation, China (Grant No. 3132030), and the Education Ministry Doctoral Fund of China (Grant No. 20120002110070).

  19. Diagnostic performance of MRI measurements to assess hindfoot malalignment. An assessment of four measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Florian M.; Hoffmann, Adrienne; Mamisch-Saupe, Nadja; Hodler, Juerg [University Hospital Balgrist and University of Zurich, Radiology, Zuerich (Switzerland); Farshad, Mazda; Espinosa, Norman [University Hospital Balgrist and University of Zurich, Department of Orthopaedic Surgery, Zuerich (Switzerland); Resnick, Donald [University of California San Diego, Department of Radiology, San Diego, CA (United States)

    2013-09-15

    To investigate the ability of coronal non-weight-bearing MR images to discriminate between normal and abnormal hindfoot alignment. Three different measurement techniques (calcaneal axis, medial/lateral calcaneal contour) based on weight-bearing hindfoot alignment radiographs were applied in 49 patients (mean, 48 years; range 21-76 years). Three groups of subjects were enrolled: (1) normal hindfoot alignment (0 -10 valgus); (2) abnormal valgus (>10 ); (3) any degree of varus hindfoot alignment. Hindfoot alignment was then measured on coronal MR images using four different measurement techniques (calcaneal axis, medial/lateral calcaneal contour, sustentaculum tangent). ROC analysis was performed to find the MR measurement with the greatest sensitivity and specificity for discrimination between normal and abnormal hindfoot alignment. The most accurate measurement on MR images to detect abnormal hindfoot valgus was the one using the medial calcaneal contour, reaching a sensitivity/specificity of 86 %/75 % using a cutoff value of >11 valgus. The most accurate measurement on MR images to detect abnormal hindfoot varus was the sustentaculum tangent, reaching a sensitivity/specificity of 91 %/71 % using a cutoff value of <12 valgus. It is possible to suspect abnormal hindfoot alignment on coronal non-weight-bearing MR images. (orig.)

  20. Temperature elevation by HIFU in ex vivo porcine muscle: MRI measurement and simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Solovchuk, Maxim A., E-mail: solovchuk@gmail.com [Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China); Hwang, San Chao; Chang, Hsu [Medical Engineering Research Division, National Health Research Institute, Miaoli 35053, Taiwan (China); Thiriet, Marc [Sorbonne Universités, UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005, Paris (France); Sheu, Tony W. H., E-mail: twhsheu@ntu.edu.tw [Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, Republic of China and Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China)

    2014-05-15

    Purpose: High-intensity focused ultrasound is a rapidly developing medical technology with a large number of potential clinical applications. Computational model can play a pivotal role in the planning and optimization of the treatment based on the patient's image. Nonlinear propagation effects can significantly affect the temperature elevation and should be taken into account. In order to investigate the importance of nonlinear propagation effects, nonlinear Westervelt equation was solved. Weak nonlinear propagation effects were studied. The purpose of this study was to investigate the correlation between the predicted and measured temperature elevations and lesion in a porcine muscle. Methods: The investigated single-element transducer has a focal length of 12 cm, an aperture of 8 cm, and frequency of 1.08 MHz. Porcine muscle was heated for 30 s by focused ultrasound transducer with an acoustic power in the range of 24–56 W. The theoretical model consists of nonlinear Westervelt equation with relaxation effects being taken into account and Pennes bioheat equation. Results: Excellent agreement between the measured and simulated temperature rises was found. For peak temperatures above 85–90 °C “preboiling” or cavitation activity appears and lesion distortion starts, causing small discrepancy between the measured and simulated temperature rises. From the measurements and simulations, it was shown that distortion of the lesion was caused by the “preboiling” activity. Conclusions: The present study demonstrated that for peak temperatures below 85–90 °C numerical simulation results are in excellent agreement with the experimental data in three dimensions. Both temperature rise and lesion size can be well predicted. Due to nonlinear effect the temperature in the focal region can be increased compared with the linear case. The current magnetic resonance imaging (MRI) resolution is not sufficient. Due to the inevitable averaging the measured

  1. Novel MRI Technique Enables Non-Invasive Measurement of Atrial Wall Thickness.

    Science.gov (United States)

    Varela, Marta; Morgan, Ross; Theron, Adeline; Dillon-Murphy, Desmond; Chubb, Henry; Whitaker, John; Henningsson, Markus; Aljabar, Paul; Schaeffter, Tobias; Kolbitsch, Christoph; Aslanidi, Oleg V

    2017-08-01

    Knowledge of atrial wall thickness (AWT) has the potential to provide important information for patient stratification and the planning of interventions in atrial arrhythmias. To date, information about AWT has only been acquired in post-mortem or poor-contrast computed tomography (CT) studies, providing limited coverage and highly variable estimates of AWT. We present a novel contrast agent-free MRI sequence for imaging AWT and use it to create personalized AWT maps and a biatrial atlas. A novel black-blood phase-sensitive inversion recovery protocol was used to image ten volunteers and, as proof of concept, two atrial fibrillation patients. Both atria were manually segmented to create subject-specific AWT maps using an average of nearest neighbors approach. These were then registered non-linearly to generate an AWT atlas. AWT was 2.4 ± 0.7 and 2.7 ± 0.7 mm in the left and right atria, respectively, in good agreement with post-mortem and CT data, where available. AWT was 2.6 ± 0.7 mm in the left atrium of a patient without structural heart disease, similar to that of volunteers. In a patient with structural heart disease, the AWT was increased to 3.1 ± 1.3 mm. We successfully designed an MRI protocol to non-invasively measure AWT and create the first whole-atria AWT atlas. The atlas can be used as a reference to study alterations in thickness caused by atrial pathology. The protocol can be used to acquire personalized AWT maps in a clinical setting and assist in the treatment of atrial arrhythmias.

  2. How bees distinguish colors

    Directory of Open Access Journals (Sweden)

    Horridge A

    2015-03-01

    Full Text Available Adrian Horridge Biological Sciences, Australian National University, Canberra, ACT, Australia Abstract: Behind each facet of the compound eye, bees have photoreceptors for ultraviolet, green, and blue wavelengths that are excited by sunlight reflected from the surrounding panorama. In experiments that excluded ultraviolet, bees learned to distinguish between black, gray, white, and various colors. To distinguish two targets of differing color, bees detected, learned, and later recognized the strongest preferred inputs, irrespective of which target displayed them. First preference was the position and measure of blue reflected from white or colored areas. They also learned the positions and a measure of the green receptor modulation at vertical edges that displayed the strongest green contrast. Modulation is the receptor response to contrast and was summed over the length of a contrasting vertical edge. This also gave them a measure of angular width between outer vertical edges. Third preference was position and a measure of blue modulation. When they returned for more reward, bees recognized the familiar coincidence of these inputs at that place. They cared nothing for colors, layout of patterns, or direction of contrast, even at black/white edges. The mechanism is a new kind of color vision in which a large-field tonic blue input must coincide in time with small-field phasic modulations caused by scanning vertical edges displaying green or blue contrast. This is the kind of system to expect in medium-lowly vision, as found in insects; the next steps are fresh looks at old observations and quantitative models. Keywords: vision, honey bee, visual processing, optimum system, picture sorting

  3. Relationship between intracranial pressure and phase contrast cine MRI derived measures of intracranial pulsations in idiopathic normal pressure hydrocephalus.

    Science.gov (United States)

    Jaeger, Matthias; Khoo, Angela K; Conforti, David A; Cuganesan, Ramesh

    2016-11-01

    Phase contrast cine MRI with determination of pulsatile aqueductal cerebrospinal fluid (CSF) stroke volume and flow velocity has been suggested to assess intracranial pulsations in idiopathic normal pressure hydrocephalus (iNPH). We aimed to compare this non-invasive measure of pulsations to intracranial pressure (ICP) pulse wave amplitude from continuous ICP monitoring. We hypothesised that a significant correlation between these two markers of intracranial pulsations exists. Fifteen patients with suspected iNPH had continuous computerised ICP monitoring with calculation of mean ICP pulse wave amplitude (MWA) from time-domain analysis. MRI measured CSF aqueductal stroke volume and peak flow velocity. Mean MWA was 5.4mmHg (range 2.3-12.4mmHg). Mean CSF stroke volume and peak flow velocity were 65μl (range 3-195μl) and 9.31cm/s (range 1.68-15.0cm/s), respectively. No significant correlation between the invasive and non-invasive measures of pulsations existed (Spearman r=-0.30 and r=-0.27, respectively; p>0.05). We observed marked intra-individual fluctuation of MWA during continuous ICP monitoring of an average of 6.0mmHg (range 2.8-12.2mmHg). The results suggest a complex interplay between measures of pulsations derived from snapshot MRI measurements and continuous computerised ICP measurements, as no significant relationship existed in our data. Further study is needed to better understand the temporal profile of CSF MRI flow studies, as substantial variation in MWA over the course of several hours of ICP monitoring is common, suggesting that these physiologic fluctuations might obscure MRI snapshot measures of intracranial pulsations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Patellar Articular Overlap on MRI Is a Simple Alternative to Conventional Measurements of Patellar Height

    Science.gov (United States)

    Munch, Jacqueline L.; Sullivan, Jaron P.; Nguyen, Joseph T.; Mintz, Douglas; Green, Daniel W.; Shubin Stein, Beth E.; Strickland, Sabrina

    2016-01-01

    Background: Patella alta describes an abnormally high-riding patella in relationship to the femur and has been shown to correlate with patellofemoral pain, instability, chondromalacia, and arthrosis. Conventional measurements of patella alta involve multiple measurements and are often not defined on cross-sectional imaging as related to radiographs. Hypothesis: Patellar articular overlap on sagittal magnetic resonance imaging (MRI) will correlate well with conventional measurements of patella alta as measured by a standardized technique defined by our group. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: MRIs of 239 knees were reviewed by 3 attending surgeons with practices focusing on patellofemoral disease, as well as 2 sports medicine fellows and 1 musculoskeletal radiologist. Measurements included articular overlap, percentage of articular coverage, Caton-Deschamps index, Blackburne-Peel index, and modified Insall-Salvati index. Results: Interrater reliability was high for Caton-Deschamps, Blackburne-Peel, and modified Insall-Salvati indices (intraclass correlation coefficient [ICC], 0.877, 0.828, and 0.787, respectively). Articular overlap and percentage articular coverage correlated well with each other (ICC, 0.961; P < .001) and with the Caton-Deschamps (overlap r = –0.271, P < .001; coverage r = –0.131, P = .037) and Blackburne-Peel (overlap r = 0.343, P < .001; coverage r = –0.238, P < .001) indices. Articular overlap and percentage coverage failed to correlate with the modified Insall-Salvati index (overlap r = –0.117, P = .091; coverage r = 0.007, P = .918). Conclusion: Patellar articular overlap and percentage of patellar articular coverage show promise as a simpler alternative to conventional, ratio-based measurements of patellar height. Future studies are needed to evaluate the range of normal and the relationship to our traditionally used measurements. PMID:27482530

  5. The effect of Gibbs ringing artifacts on measures derived from diffusion MRI

    NARCIS (Netherlands)

    Perrone, Daniele; Aelterman, Jan; Pižurica, Aleksandra; Jeurissen, Ben; Philips, Wilfried; Leemans, A

    2015-01-01

    Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a unique method to investigate microstructural tissue properties noninvasively and is one of the most popular methods for studying the brain white matter in vivo. To obtain reliable statistical inferences with diffusion MRI, however, there

  6. Cerebrospinal fluid volumetric MRI mapping as a simple measurement for evaluating brain atrophy

    NARCIS (Netherlands)

    De Vis, J B; Zwanenburg, J J|info:eu-repo/dai/nl/290473683; van der Kleij, L A; Spijkerman, J M; Biessels, G J|info:eu-repo/dai/nl/165576367; Hendrikse, J|info:eu-repo/dai/nl/266590268; Petersen, E T

    2016-01-01

    OBJECTIVES: To assess whether volumetric cerebrospinal fluid (CSF) MRI can be used as a surrogate for brain atrophy assessment and to evaluate how the T2 of the CSF relates to brain atrophy. METHODS: Twenty-eight subjects [mean age 64 (sd 2) years] were included; T1-weighted and CSF MRI were perform

  7. Reliability and agreement of adipose tissue fat fraction measurements with water-fat MRI in patients with manifest cardiovascular disease

    NARCIS (Netherlands)

    Franssens, Bas T; Eikendal, Anouk L; Leiner, Tim; van der Graaf, Yolanda|info:eu-repo/dai/nl/072825847; Visseren, Frank L J|info:eu-repo/dai/nl/166267678; Hoogduin, J M|info:eu-repo/dai/nl/158071956

    2016-01-01

    The supraclavicular fat depot is known for brown adipose tissue presence. To unravel adipose tissue physiology and metabolism, high quality and reproducible imaging is required. In this study we quantified the reliability and agreement of MRI fat fraction measurements in supraclavicular and subcutan

  8. Measurement of the arterial concentration of Gd-DTPA using MRI: a step toward quantitative perfusion imaging

    DEFF Research Database (Denmark)

    Fritz-Hansen, T; Rostrup, Egill; Larsson, H B;

    1996-01-01

    accordance between the two input functions was found, indicating that it is possible to measure the input function to the myocardium using MRI. A variation between the two concentration curves of 5% at upslope, 2.7% at peak point, and 7% at downslope was found. The study also indicates that a short...

  9. Reliability and agreement of adipose tissue fat fraction measurements with water-fat MRI in patients with manifest cardiovascular disease

    NARCIS (Netherlands)

    Franssens, Bas T; Eikendal, Anouk L; Leiner, Tim; van der Graaf, Yolanda; Visseren, Frank L J; Hoogduin, J M

    2016-01-01

    The supraclavicular fat depot is known for brown adipose tissue presence. To unravel adipose tissue physiology and metabolism, high quality and reproducible imaging is required. In this study we quantified the reliability and agreement of MRI fat fraction measurements in supraclavicular and subcutan

  10. Quantification of MRI measured myocardial perfusion reserve in healthy humans: A comparison with positron emission tomography

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Hove, J.D.; Kofoed, K.F.;

    2008-01-01

    and during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd-DTPA-enhanced MRI and N-13-ammonia PET were fitted by a two-compartment perfusion model. Results: Mean perfusion values (+/- SD) derived from the MRI......Purpose: To validate a noninvasive quantitative MRI technique, the K-i perfusion method, for myocardial perfusion in humans using N-13-ammonia PET as a reference method. Materials and Methods: Ten healthy males (64 +/- 8 years) were examined with combined PET and MRI perfusion imaging at rest...... method at rest and at hyperemia were 80 +/- 20 and 183 +/- 56 mL/min/100 g, respectively. The same data for PET were 71 +/- 16 and 203 +/- 67 mL/min/100 g. A linear relationship was observed between MRI and PET-derived myocardial perfusion reserve for regional and global data. Linear regression...

  11. Comparison of Global Cerebral Blood Flow Measured by Phase-Contrast Mapping MRI with O-15-H2O Positron Emission Tomography

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob

    2017-01-01

    Purpose To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by 15O-H2O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo...

  12. Reproducibility of BOLD, perfusion, and CMRO2 measurements with calibrated-BOLD fMRI.

    Science.gov (United States)

    Leontiev, Oleg; Buxton, Richard B

    2007-03-01

    The coupling of changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO(2)) during brain activation can be characterized by an empirical index, n, defined as the ratio between fractional CBF change and fractional CMRO(2) change. The combination of blood oxygenation level dependent (BOLD) imaging with CBF measurements from arterial spin labeling (ASL) provides a potentially powerful experimental approach for measuring n, but the reproducibility of the technique previously has not been assessed. In this study, inter-subject variance and intra-subject reproducibility of the method were determined. Block design %BOLD and %CBF responses to visual stimulation and mild hypercapnia (5% CO(2)) were measured, and these data were used to compute the BOLD scaling factor M, %CMRO(2) change with activation, and the coupling index n. Reproducibility was determined for three approaches to defining regions-of-interest (ROIs): 1) Visual area V1 determined from prior retinotopic maps, 2) BOLD-activated voxels from a separate functional localizer, and 3) CBF-activated voxels from a separate functional localizer. For estimates of %BOLD, %CMRO(2) and n, intra-subject reproducibility was found to be best for regions selected according to CBF activation. Among all fMRI measurements, estimates of n were the most robust and were substantially more stable within individual subjects (coefficient of variation, CV=7.4%) than across the subject pool (CV=36.9%). The stability of n across days, despite wider variability of CBF and CMRO(2) responses, suggests that the reproducibility of blood flow changes is limited by variation in the oxidative metabolic demand. We conclude that the calibrated BOLD approach provides a highly reproducible measurement of n that can serve as a useful quantitative probe of the coupling of blood flow and energy metabolism in the brain.

  13. Repeatability of cardiac-MRI-measured right ventricular size and function in congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Rowan; Salem, Yishay [Mount Sinai School of Medicine, Division of Pediatric Cardiology, New York, NY (United States); Shah, Amee; Lai, Wyman W. [Morgan Stanley Children' s Hospital of New York Presbyterian, New York, NY (United States); Nielsen, James C. [Mount Sinai School of Medicine, Division of Pediatric Cardiology, New York, NY (United States); Mount Sinai Children' s Heart Center, Box 1201, New York, NY (United States)

    2011-08-15

    The measurement error for right ventricular (RV) size and function assessed by cardiac MRI (CMRI) in congenital heart disease has not been fully characterized. As CMRI parameters are being increasingly utilized to make clinical decisions, defining error in the clinical setting is critical. This investigation examines the repeatability of CMRI for RV size and function. Forty consecutive people with congenital heart disease involving the RV were retrospectively identified. Contouring of RV volumes was performed by two expert CMRI clinicians. The coefficient of variability and repeatability coefficients were calculated. Repeatability coefficients were multiplied by the mean value for each group studied to define a threshold beyond which measurement error was unlikely to be responsible. The variability for indexed RV end-diastolic volume = 3.2% and 3.3% for intra- and interobserver comparisons, respectively. The repeatability coefficients were 13.2% and 14.9% for intra- and interobserver comparisons, which yielded threshold values of 15.1 ml/m{sup 2} and 20.2 ml/m{sup 2}, respectively. For RV ejection fraction (EF), the repeatability coefficients for intra- and interobserver comparisons were 5.0% and 6.0%, which resulted in threshold values of 2.6 EF% and 3.0 EF%. The threshold values generated can be used during serial assessment of RV size and function. (orig.)

  14. An fMRI-compatible force measurement system for the evaluation of the neural correlates of step initiation.

    Science.gov (United States)

    de Lima-Pardini, Andrea Cristina; de Azevedo Neto, Raymundo Machado; Coelho, Daniel Boari; Boffino, Catarina Costa; Shergill, Sukhwinder S; de Oliveira Souza, Carolina; Brant, Rachael; Barbosa, Egberto Reis; Cardoso, Ellison Fernando; Teixeira, Luis Augusto; Cohen, Rajal G; Horak, Fay Bahling; Amaro, Edson

    2017-02-23

    Knowledge of brain correlates of postural control is limited by the technical difficulties in performing controlled experiments with currently available neuroimaging methods. Here we present a system that allows the measurement of anticipatory postural adjustment of human legs to be synchronized with the acquisition of functional magnetic resonance imaging data. The device is composed of Magnetic Resonance Imaging (MRI) compatible force sensors able to measure the level of force applied by both feet. We tested the device in a group of healthy young subjects and a group of elderly subjects with Parkinson's disease using an event-related functional MRI (fMRI) experiment design. In both groups the postural behavior inside the magnetic resonance was correlated to the behavior during gait initiation outside the scanner. The system did not produce noticeable imaging artifacts in the data. Healthy young people showed brain activation patterns coherent with movement planning. Parkinson's disease patients demonstrated an altered pattern of activation within the motor circuitry. We concluded that this force measurement system is able to index both normal and abnormal preparation for gait initiation within an fMRI experiment.

  15. An fMRI-compatible force measurement system for the evaluation of the neural correlates of step initiation

    Science.gov (United States)

    de Lima-Pardini, Andrea Cristina; de Azevedo Neto, Raymundo Machado; Coelho, Daniel Boari; Boffino, Catarina Costa; Shergill, Sukhwinder S.; de Oliveira Souza, Carolina; Brant, Rachael; Barbosa, Egberto Reis; Cardoso, Ellison Fernando; Teixeira, Luis Augusto; Cohen, Rajal G.; Horak, Fay Bahling; Amaro, Edson

    2017-01-01

    Knowledge of brain correlates of postural control is limited by the technical difficulties in performing controlled experiments with currently available neuroimaging methods. Here we present a system that allows the measurement of anticipatory postural adjustment of human legs to be synchronized with the acquisition of functional magnetic resonance imaging data. The device is composed of Magnetic Resonance Imaging (MRI) compatible force sensors able to measure the level of force applied by both feet. We tested the device in a group of healthy young subjects and a group of elderly subjects with Parkinson’s disease using an event-related functional MRI (fMRI) experiment design. In both groups the postural behavior inside the magnetic resonance was correlated to the behavior during gait initiation outside the scanner. The system did not produce noticeable imaging artifacts in the data. Healthy young people showed brain activation patterns coherent with movement planning. Parkinson’s disease patients demonstrated an altered pattern of activation within the motor circuitry. We concluded that this force measurement system is able to index both normal and abnormal preparation for gait initiation within an fMRI experiment. PMID:28230070

  16. The measurement of free erythrocyte porphyrin (FEP) as a simple means of distinguishing iron deficiency from beta-thalassemia trait in subjects with microcytosis.

    Science.gov (United States)

    Stockman, J A; Weiner, L S; Simon, G E; Stuart, M J; Oski, F A

    1975-01-01

    Assay of free erythrocyte porphyrin (FEP) and measurement of red cell indices were obtained in a group of subjects with iron deficiency and beta-thalassemia trait to determine if these studies cound detect these disorders and discriminate bbetween them. FEP values were increased in 90.2 per cent of subjects with iron deficiency but were within the normal range in 96.6 per cent of subjects with beta-thalassemia trait. Mean FEP values increased sligtly as transferrin saturation fell but became abnormally elevated when the transferrin saturation fell but became abnormally elevated when the transferrin saturation was less than 15 per cent. Unlike subjecs with iron deficiency in whom the mean corpuscular volume varied from 46 to 84, all individuals with beta-thalassermia trait exhibited microcytosis. In most instances, determination of FEP appears to distinguish beta-thalassemia trait from iron deficiency in patients with microcytosis.

  17. Anatomic guidelines defined by reformatting images on MRI for volume measurement of amygdala and hippocampus

    Energy Technology Data Exchange (ETDEWEB)

    Hoshida, Tohru; Sakaki, Toshisuke [Nara Medical Univ., Kashihara (Japan); Uematsu, Sumio

    1995-03-01

    Twelve patients with intractable partial epilepsy underwent MR scans at the Epilepsy Center of the Johns Hopkins Hospital. There were five women and seven men, ranging in age from five to 51 years (mean age: 26 years). Coronal images were obtained using a 3-D SPGR. The coronal images were transferred to an Allegro 5.1 workstation, and reformatted along the cardinal axes (axial and sagittal) in multiple view points. The anterior end of the amygdala was measured at the level just posterior to the disappearance of the temporal stem. The semilunar gyrus of the amygdala was separated from the ambient gyrus by the semianular sulcus that forms the boundary between the amygdala and the entorhinal cortex. The delineation of the hippocampal formation included the subicular complex, hippocampal proper, dentate gyrus, alveus, and fimbria. The uncal cleft separated the uncus above from the parahippocampal gyrus below. The roof of this cleft was formed by the hippocampus and the dentate gyrus, and the floor, by the presubiculum and subiculum. Although using some guidelines, strictly separating the hippocampal head from the posterior part of the amygdala was not feasible as was previously reported, because of the isointensity on MRI between the cortex of the amygdala and the hippocampus. The most posterior portion of the hippocampus was measured at the level of the subsplenial gyri, just below the splenium of the corpus callosum, to measure the hippocampal volume in its near totality. Therefore, it is reliable, and clinically useful, to measure the combined total volume of the amygdala and the hippocampus when comparing results with those of other centers. (S.Y.).

  18. Feasibility study of high-resolution DCE-MRI for glomerular filtration rate (GFR) measurement in a routine clinical modal.

    Science.gov (United States)

    Zhang, Yu-Dong; Wu, Chen-Jiang; Zhang, Jing; Wang, Xiao-Ning; Liu, Xi-Sheng; Shi, Hai-Bin

    2015-10-01

    Dynamic contrast enhanced (DCE) MR renography has been identified as an interesting tool to determine single-kidney GFR. However, a fundamental issue for the applicability of MR-based estimate of single-kidney GFR is selecting a balance between spatial and temporal resolution of DCE-MRI data. The purpose is to assess the feasibility of GFR estimate from high-resolution (HR) dynamic contrast-enhanced (DCE) MRI in a routine clinical modal. Standard MR renography (2.4s/phase, total 4min; 4-ml Gd) and five-phase, HR-based imaging protocol (0, 30, 70, 120, and 240s; 0.05mmol/kg Gd) were prospectively performed in twelve volunteers who were scheduled for routine renal MRI. Data were plotted with Patlak, two-compartment modified Tofts model (2CTM), and two-compartment filtration model (2CFM) for GFR estimate. During all the measurements, only the signal intensities in the aorta and whole kidney parenchyma were considered. Standard 2CFM and 2CTM produced lower residuals over the fitted interval than HR-based measures (pGFR and higher residuals than that plots with 0-120s data points (pGFR with HR-based DCE-MRI and appreciate kinetic model. Patlak plots from 0, 30, 70, and 120s data points is better than plots from 0, 30, 70, 120, and 240s data points.

  19. Multisite evaluations of a T2 -relaxation-under-spin-tagging (TRUST) MRI technique to measure brain oxygenation.

    Science.gov (United States)

    Liu, Peiying; Dimitrov, Ivan; Andrews, Trevor; Crane, David E; Dariotis, Jacinda K; Desmond, John; Dumas, Julie; Gilbert, Guillaume; Kumar, Anand; Maclntosh, Bradley J; Tucholka, Alan; Yang, Shaolin; Xiao, Guanghua; Lu, Hanzhang

    2016-02-01

    Venous oxygenation (Yv ) is an important index of brain physiology and may be indicative of brain diseases. A T2 -relaxation-under-spin-tagging (TRUST) MRI technique was recently developed to measure Yv . A multisite evaluation of this technique would be an important step toward broader availability and potential clinical utilizations of Yv measures. TRUST MRI was performed on a total of 250 healthy subjects, 125 from the developer's site and 25 each from five other sites. All sites were equipped with a 3 Tesla (T) MRI of the same vendor. The estimated Yv and the standard error (SE) of the estimation εYv were compared across sites. The averaged Yv and εYv across six sites were 61.1% ± 1.4% and 1.3% ± 0.2%, respectively. Multivariate regression analysis showed that the estimated Yv was dependent on age (P = 0.009) but not on performance site. In contrast, the SE of the Yv estimation was site-dependent (P = 0.024) but was less than 1.5%. Further analysis revealed that εYv was positively associated with the amount of subject motion (P < 0.001) but negatively associated with blood signal intensity (P < 0.001). This work suggests that TRUST MRI can yield equivalent results of Yv estimation across different sites. © 2015 Wiley Periodicals, Inc.

  20. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Waahlin, Anders

    2012-07-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  1. Measuring fMRI reliability with the intra-class correlation coefficient.

    Science.gov (United States)

    Caceres, Alejandro; Hall, Deanna L; Zelaya, Fernando O; Williams, Steven C R; Mehta, Mitul A

    2009-04-15

    The intra-class class correlation coefficient (ICC) is a prominent statistic to measure test-retest reliability of fMRI data. It can be used to address the question of whether regions of high group activation in a first scan session will show preserved subject differentiability in a second session. With this purpose, we present a method that extends voxel-wise ICC analysis. We show that voxels with high group activation have more probability of being reliable, if a subsequent session is performed, than typical voxels across the brain or across white matter. We also find that the existence of some voxels with high ICC but low group activation can be explained by stable signals across sessions that poorly fit the HRF model. At a region of interest level, we show that our voxel-wise ICC calculation is more robust than previous implementations under variations of smoothing and cluster size. The method also allows formal comparisons between the reliabilities of given brain regions; aimed at establishing which ROIs discriminate best between individuals. The method is applied to an auditory and a verbal working memory task. A reliability toolbox for SPM5 is provided at http://brainmap.co.uk.

  2. Quantitative MRI for hepatic fat fraction and T2* measurement in pediatric patients with non-alcoholic fatty liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Jie; Rigsby, Cynthia K.; Donaldson, James S. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States); Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Fishbein, Mark H. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Division of Gastroenterology, Hepatology, and Nutrition, Chicago, IL (United States); Zhang, Gang [Ann and Robert H. Lurie Children' s Hospital of Chicago, Biostatistics Research Core, Chicago, IL (United States); Schoeneman, Samantha E. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States)

    2014-11-15

    Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in children. The gold standard for diagnosis is liver biopsy. MRI is a non-invasive imaging method to provide quantitative measurement of hepatic fat content. The methodology is particularly appealing for the pediatric population because of its rapidity and radiation-free imaging techniques. To develop a multi-point Dixon MRI method with multi-interference models (multi-fat-peak modeling and bi-exponential T2* correction) for accurate hepatic fat fraction (FF) and T2* measurements in pediatric patients with NAFLD. A phantom study was first performed to validate the accuracy of the MRI fat fraction measurement by comparing it with the chemical fat composition of the ex-vivo pork liver-fat homogenate. The most accurate model determined from the phantom study was used for fat fraction and T2* measurements in 52 children and young adults referred from the pediatric hepatology clinic with suspected or identified NAFLD. Separate T2* values of water (T2*{sub W}) and fat (T2*{sub F}) components derived from the bi-exponential fitting were evaluated and plotted as a function of fat fraction. In ten patients undergoing liver biopsy, we compared histological analysis of liver fat fraction with MRI fat fraction. In the phantom study the 6-point Dixon with 5-fat-peak, bi-exponential T2* modeling demonstrated the best precision and accuracy in fat fraction measurements compared with other methods. This model was further calibrated with chemical fat fraction and applied in patients, where similar patterns were observed as in the phantom study that conventional 2-point and 3-point Dixon methods underestimated fat fraction compared to the calibrated 6-point 5-fat-peak bi-exponential model (P < 0.0001). With increasing fat fraction, T2*{sub W} (27.9 ± 3.5 ms) decreased, whereas T2*{sub F} (20.3 ± 5.5 ms) increased; and T2*{sub W} and T2*{sub F} became increasingly more similar when fat

  3. Colon wall motility: comparison of novel quantitative semi-automatic measurements using cine MRI

    OpenAIRE

    Hoad, Caroline; Menys, A.; Garsed, Klara; Marciani, Luca; Hamy, Valentin; Murray, Kathryn; Costigan, Carolyn; Atkinson, D.; Major, Giles; Spiller, Robin C; Taylor, S.; Gowland, Penny A.

    2016-01-01

    Background\\ud \\ud Recently, cine magnetic resonance imaging (MRI) has shown promise for visualizing movement of the colonic wall, although assessment of data has been subjective and observer dependent. This study aimed to develop an objective and semi-automatic imaging metric of ascending colonic wall movement, using image registration techniques.\\ud Methods\\ud \\ud Cine balanced turbo field echo MRI images of ascending colonic motility were acquired over 2 min from 23 healthy volunteers (HVs)...

  4. Data Mining of Satellite-Based Measurements to Distinguish Natural From Man-Made Oil Slicks at the Sea Surface in Campeche Bay (Mexico)

    Science.gov (United States)

    Carvalho, G. D. A.; Minnett, P. J.; de Miranda, F. P.; Landau, L.; Paes, E.

    2016-02-01

    Campeche Bay, located in the Mexican portion of the Gulf of Mexico, has a well-established activity engaged with numerous oil rigs exploring and producing natural gas and oil. The associated risk of oil slicks in this region - that include oil spills (i.e. oil floating at the sea surface solely attributed to man-made activities) and oil seeps (i.e. surface footprint of the oil that naturally comes out of the seafloor reaching the surface of the ocean) - leads Pemex to be in a continuous state of alert for reducing possible negative influence on marine and coastal ecosystems. Focusing on a monitoring strategy, a multi-year dataset (2008-2012) of synthetic aperture radar (SAR) measurements from the RADARSAT-2 satellite is used to investigate the spatio-temporal distribution of the oil slicks observed at the surface of the ocean in the Campeche Bay region. The present study is an exploratory data analysis that seeks to discriminate between these two possible oil slick types: oil seeps and oil spills. Multivariate data analysis techniques (e.g. Principal Components Analysis, Clustering Analysis, Discriminant Function, etc.) are explored to design a data-learning classification algorithm to distinguish natural from man-made oil slicks. This analysis promotes a novel idea bridging geochemistry and remote sensing research to express geophysical differences between seeped and spilled oil. Here, SAR backscatter coefficients - i.e. sigma-naught (σo), beta-naught (βo), and gamma-naught (γo) - are combined with attributes referring to the geometry, shape, and dimension that describe the oil slicks. Results indicate that the synergy of combining these various characteristics is capable of distinguishing oil seeps from oil spills observed on the sea surface to a useful accuracy.

  5. Distinguishing the roles of meteorology, emission control measures, regional transport, and co-benefits of reduced aerosol feedbacks in ;APEC Blue;

    Science.gov (United States)

    Gao, Meng; Liu, Zirui; Wang, Yuesi; Lu, Xiao; Ji, Dongsheng; Wang, Lili; Li, Meng; Wang, Zifa; Zhang, Qiang; Carmichael, Gregory R.

    2017-10-01

    Air quality are strongly influenced by both emissions and meteorological conditions. During the Asia Pacific Economic Cooperation (APEC) week (November 5-11, 2014), the Chinese government implemented unprecedented strict emission control measures in Beijing and surrounding provinces, and then a phenomenon referred to as "APEC Blue" (rare blue sky) occurred. It is challenging to quantify the effectiveness of the implemented strict control measures solely based on observations. In this study, we use the WRF-Chem model to distinguish the roles of meteorology, emission control measures, regional transport, and co-benefits of reduced aerosol feedbacks during APEC week. In general, meteorological variables, PM2.5 concentrations and PM2.5 chemical compositions are well reproduced in Beijing. Positive weather conditions (lower temperature, lower relative humidity, higher wind speeds and enhanced boundary layer heights) play important roles in "APEC Blue". Applying strict emission control measures in Beijing and five surrounding provinces can only explain an average decrease of 17.7 μg/m3 (-21.8%) decreases in PM2.5 concentrations, roughly more than half of which is caused by emission controls that implemented in the five surrounding provinces (12.5 μg/m3). During the APEC week, non-local emissions contributed to 41.3% to PM2.5 concentrations in Beijing, and the effectiveness of implementing emission control measures hinges on dominant pathways and transport speeds. Besides, we also quantified the contribution of reduced aerosol feedbacks due to strict emission control measures in this study. During daytime, co-benefits of reduced aerosol feedbacks account for about 10.9% of the total decreases in PM2.5 concentrations in urban Beijing. The separation of contributions from aerosol absorption and scattering restates the importance of controlling BC to accelerate the effectiveness of aerosol pollution control.

  6. Accuracy of respiratory motion measurement of 4D-MRI: A comparison between cine and sequential acquisition.

    Science.gov (United States)

    Liu, Yilin; Yin, Fang-Fang; Rhee, DongJoo; Cai, Jing

    2016-01-01

    The authors have recently developed a cine-mode T2*/T1-weighted 4D-MRI technique and a sequential-mode T2-weighted 4D-MRI technique for imaging respiratory motion. This study aims at investigating which 4D-MRI image acquisition mode, cine or sequential, provides more accurate measurement of organ motion during respiration. A 4D digital extended cardiac-torso (XCAT) human phantom with a hypothesized tumor was used to simulate the image acquisition and the 4D-MRI reconstruction. The respiratory motion was controlled by the given breathing signal profiles. The tumor was manipulated to move continuously with the surrounding tissue. The motion trajectories were measured from both sequential- and cine-mode 4D-MRI images. The measured trajectories were compared with the average trajectory calculated from the input profiles, which was used as references. The error in 4D-MRI tumor motion trajectory (E) was determined. In addition, the corresponding respiratory motion amplitudes of all the selected 2D images for 4D reconstruction were recorded. Each of the amplitude was compared with the amplitude of its associated bin on the average breathing curve. The mean differences from the average breathing curve across all slice positions (D) were calculated. A total of 500 simulated respiratory profiles with a wide range of irregularity (Ir) were used to investigate the relationship between D and Ir. Furthermore, statistical analysis of E and D using XCAT controlled by 20 cancer patients' breathing profiles was conducted. Wilcoxon Signed Rank test was conducted to compare two modes. D increased faster for cine-mode (D = 1.17 × Ir + 0.23) than sequential-mode (D = 0.47 × Ir + 0.23) as irregularity increased. For the XCAT study using 20 cancer patients' breathing profiles, the median E values were significantly different: 0.12 and 0.10 cm for cine- and sequential-modes, respectively, with a p-value of 0.02. The median D values were significantly different: 0.47 and 0.24 cm for cine

  7. CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

    Energy Technology Data Exchange (ETDEWEB)

    Karlo, C., E-mail: christoph.karlo@usz.c [Institute of Diagnostic Radiology, Department of Radiology, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Reiner, C.S.; Stolzmann, P. [Institute of Diagnostic Radiology, Department of Radiology, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Breitenstein, S. [Department of Visceral Surgery, University Hospital of Zurich (Switzerland); Marincek, B. [Institute of Diagnostic Radiology, Department of Radiology, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Weishaupt, D. [Institute for Radiology and Radiodiagnostics, City Hospital Triemli, Zurich (Switzerland); Frauenfelder, T. [Institute of Diagnostic Radiology, Department of Radiology, University Hospital of Zurich, Raemistrasse 100, 8091 Zurich (Switzerland)

    2010-07-15

    Objective: To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation. Methods: Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated. Results: Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI). Conclusion: CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.

  8. MR measurement of luminal water in prostate gland: Quantitative correlation between MRI and histology.

    Science.gov (United States)

    Sabouri, Shirin; Fazli, Ladan; Chang, Silvia D; Savdie, Richard; Jones, Edward C; Goldenberg, S Larry; Black, Peter C; Kozlowski, Piotr

    2017-09-01

    To determine the relationship between parameters measured from luminal water imaging (LWI), a new magnetic resonance imaging (MRI) T2 mapping technique, and the corresponding tissue composition in prostate. In all, 17 patients with prostate cancer were examined with a 3D multiecho spin echo sequence at 3T prior to undergoing radical prostatectomy. Maps of seven MR parameters, called N, T2-short , T2-long , Ashort , Along , geometric mean T2 time (gmT2 ), and luminal water fraction (LWF), were generated using nonnegative least squares (NNLS) analysis of the T2 decay curves. MR parametric maps were correlated to digitized whole-mount histology sections. Percentage area of tissue components, including luminal space, nuclei, and cytoplasm plus stroma, was measured on the histology sections by using color-based image segmentation. Spearman's rank correlation test was used to evaluate the correlation between MR parameters and the corresponding tissue components, with particular attention paid to the correlation between LWF and percentage area of luminal space. N, T2-short , Along , gmT2 , and LWF showed significant correlation (P correlation (P correlation was observed between LWF and luminal space (Spearman's coefficient of rank correlation = 0.75, P correlated with the fractional amount of luminal space in prostatic tissue. This result suggests that LWI can potentially be applied for evaluation of prostatic diseases in which the extent of luminal space differs between normal and abnormal tissues. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:861-869. © 2017 International Society for Magnetic Resonance in Medicine.

  9. MRI-based hip cartilage measures in osteoarthritic and non-osteoarthritic individuals: a systematic review

    Science.gov (United States)

    Aguilar, Hector N; Battié, Michele C

    2017-01-01

    Osteoarthritis is a common hip joint disease, involving loss of articular cartilage. The prevalence and prognosis of hip osteoarthritis have been difficult to determine, with various clinical and radiological methods used to derive epidemiological estimates exhibiting significant heterogeneity. MRI-based methods directly visualise hip joint cartilage, and offer potential to more reliably define presence and severity of osteoarthritis, but have been underused. We performed a systematic review of MRI-based estimates of hip articular cartilage in the general population and in patients with established osteoarthritis, using MEDLINE, EMBASE and SCOPUS current to June 2016, with search terms such as ‘hip’, ‘femoral head’, ‘cartilage’, ‘volume’, ‘thickness’, ‘MRI’, etc. Ultimately, 11 studies were found appropriate for inclusion, but they were heterogeneous in osteoarthritis assessment methodology and composition. Overall, the studies consistently demonstrate the reliability and potential clinical utility of MRI-based estimates. However, no longitudinal data or reference values for hip cartilage thickness or volume have been published, limiting the ability of MRI to define or risk-stratify hip osteoarthritis. MRI-based techniques are available to quantify articular cartilage signal, volume, thickness and defects, which could establish the sequence and rate of articular cartilage changes at the hip that yield symptomatic osteoarthritis. However, prevalence and rates of progression of hip osteoarthritis have not been established in any MRI studies in the general population. Future investigations could fill this important knowledge gap using robust MRI methods in population-based cross-sectional and longitudinal studies. PMID:28405471

  10. Comparison of scar thickness measurements using trans-vaginal sonography and MRI in cases of pregnancy with previous caesarean section. Do they correlate with actual scar thickness?

    Science.gov (United States)

    Singh, N; Tripathi, R; Mala, Y M; Dixit, R; Tyagi, S; Batra, A

    2013-11-01

    The aim of this study was to evaluate scar thickness in cases of pregnancy with previous caesarean section, by trans-vaginal sonography (TVS) and magnetic resonance imaging (MRI), and to correlate precision of radiologically-measured scar thickness with actual measurement of scar thickness. A total of 35 pregnant patients with previous caesarean section planned for elective caesarean section, were evaluated prospectively. Their scar thickness was measured by TVS and MRI on the day of elective repeat caesarean section. These measurements were correlated with each other and with scar thickness measured during elective repeat caesarean section by using a caliper. The correlation coefficients between scar thickness measured by TVS and MRI with peroperative evaluation with a caliper, were +0.72 and +0.59, respectively. The study concluded that as MRI is a costlier modality and TVS has better correlation coefficient with actual scar thickness, TVS can be considered to be the better modality for antenatal scar thickness measurement.

  11. A novel approach to calibrate the Hemodynamic Model using functional Magnetic Resonance Imaging (fMRI) measurements

    KAUST Repository

    Khoram, Nafiseh

    2016-01-21

    Background The calibration of the hemodynamic model that describes changes in blood flow and blood oxygenation during brain activation is a crucial step for successfully monitoring and possibly predicting brain activity. This in turn has the potential to provide diagnosis and treatment of brain diseases in early stages. New Method We propose an efficient numerical procedure for calibrating the hemodynamic model using some fMRI measurements. The proposed solution methodology is a regularized iterative method equipped with a Kalman filtering-type procedure. The Newton component of the proposed method addresses the nonlinear aspect of the problem. The regularization feature is used to ensure the stability of the algorithm. The Kalman filter procedure is incorporated here to address the noise in the data. Results Numerical results obtained with synthetic data as well as with real fMRI measurements are presented to illustrate the accuracy, robustness to the noise, and the cost-effectiveness of the proposed method. Comparison with Existing Method(s) We present numerical results that clearly demonstrate that the proposed method outperforms the Cubature Kalman Filter (CKF), one of the most prominent existing numerical methods. Conclusion We have designed an iterative numerical technique, called the TNM-CKF algorithm, for calibrating the mathematical model that describes the single-event related brain response when fMRI measurements are given. The method appears to be highly accurate and effective in reconstructing the BOLD signal even when the measurements are tainted with high noise level (as high as 30%).

  12. Evaluating the reliability of different preprocessing steps to estimate graph theoretical measures in resting state fMRI data.

    Science.gov (United States)

    Aurich, Nathassia K; Alves Filho, José O; Marques da Silva, Ana M; Franco, Alexandre R

    2015-01-01

    With resting-state functional MRI (rs-fMRI) there are a variety of post-processing methods that can be used to quantify the human brain connectome. However, there is also a choice of which preprocessing steps will be used prior to calculating the functional connectivity of the brain. In this manuscript, we have tested seven different preprocessing schemes and assessed the reliability between and reproducibility within the various strategies by means of graph theoretical measures. Different preprocessing schemes were tested on a publicly available dataset, which includes rs-fMRI data of healthy controls. The brain was parcellated into 190 nodes and four graph theoretical (GT) measures were calculated; global efficiency (GEFF), characteristic path length (CPL), average clustering coefficient (ACC), and average local efficiency (ALE). Our findings indicate that results can significantly differ based on which preprocessing steps are selected. We also found dependence between motion and GT measurements in most preprocessing strategies. We conclude that by using censoring based on outliers within the functional time-series as a processing, results indicate an increase in reliability of GT measurements with a reduction of the dependency of head motion.

  13. The association between Placental T2* measured by MRI in dichorionic twin pregnancies and intertwin birth weight differences

    DEFF Research Database (Denmark)

    Sørensen, Anne Nødgaard Weidemann; Sinding, Marianne Munk; Peters, David Alberg;

    ABSTRACT FINAL ID: P22.06 TITLE: The association between Placental T2* measured by MRI in dichorionic twin pregnancies and intertwin birth weight differences AUTHORS (FIRST NAME, LAST NAME): Anne Sørensen1, 2, Marianne Sinding1, David Peters3, Jens B. Frøkjær4, 2, Astrid Petersen6, Niels Uldbjerg5...... the association between the intertwin placental T2* difference and the intertwin birth weight difference Methods: A total of 21 dichorionic twin pregnancies (gestational age 20.1 – 34.1 weeks) were included in this study and placental T2* was measured using a gradient recalled echo MRI sequence with readout at 16......: Intertwin placental T2* difference is strongly related to intertwin birthweight difference, even when performed several weeks before birth. Placental T2* might be a future method to predict intertwin birthweight difference in dichorionic twin pregnancies. Further studies should be performed in order...

  14. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain (ventricles) causes of epilepsy ( ... may not always distinguish between cancer tissue and fluid, known as edema . MRI typically costs more and ...

  15. Reproducibility, and age, body-weight and gender dependency of candidate skeletal muscle MRI outcome measures in healthy volunteers

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Jasper M.; Reilly, Mary M.; Hanna, Michael G. [UCL Institute of Neurology, Medical Research Council Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, London (United Kingdom); Sinclair, Christopher D.J.; Yousry, Tarek A.; Thornton, John S. [UCL Institute of Neurology, Medical Research Council Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); Fischmann, Arne [University of Basel Hospital, Department of Radiology, Division of Diagnostic and Interventional Neuroradiology, Basel (Switzerland)

    2014-07-15

    Quantitative magnetic resonance imaging (MRI) can potentially meet the pressing need for objective, sensitive, reproducible outcome measures in neuromuscular disease trials. We tested, in healthy volunteers, the consistency, reliability and sensitivity to normal inter-subject variation of MRI methods targeted to lower limb muscle pathology to inform the design of practical but comprehensive MRI outcome measure protocols for use in imminent patient studies. Forty-seven healthy volunteers, age 21-81 years, were subject at 3T to three-point Dixon fat-fraction measurement, T{sub 1}-relaxometry, T{sub 2}-relaxometry and magnetisation transfer ratio (MTR) imaging at mid-thigh and mid-calf level bilaterally. Fifteen subjects underwent repeat imaging at 2 weeks. Mean between-muscle fat fraction and T{sub 2} differences were small, but significant (p < 0.001). Fat fraction and T{sub 2} correlated positively, and MTR negatively with subject age in both the thigh and calf, with similar significant correlations with weight at thigh level only (p < 0.001 to p < 0.05). Scan-rescan and inter-observer intra-class correlation coefficients ranged between 0.62-0.84 and 0.79-0.99 respectively. Quantitative lower-limb muscle MRI using readily implementable methods was sensitive enough to demonstrate inter-muscle differences (small in health), and correlations with subject age and weight. In combination with high reliability, this strongly supports the suitability of these methods to provide longitudinal outcome measures in neuromuscular disease treatment trials. (orig.)

  16. Accuracy of model-based tracking of knee kinematics and cartilage contact measured by dynamic volumetric MRI.

    Science.gov (United States)

    Kaiser, Jarred; Monawer, Arezu; Chaudhary, Rajeev; Johnson, Kevin M; Wieben, Oliver; Kijowski, Richard; Thelen, Darryl G

    2016-10-01

    The purpose of this study was to determine the accuracy of knee kinematics and cartilage contact measured by volumetric dynamic MRI. A motor-actuated phantom drove femoral and tibial bone segments through cyclic 3D motion patterns. Volumetric images were continuously acquired using a 3D radially undersampled cine spoiled gradient echo sequence (SPGR-VIPR). Image data was binned based on position measured via a MRI-compatible rotary encoder. High-resolution static images were segmented to create bone models. Model-based tracking was performed by optimally registering the bone models to the volumetric images at each frame of the SPGR-VIPR series. 3D tibiofemoral translations and orientations were reconstructed, and compared to kinematics obtained by tracking fiducial markers. Imaging was repeated on a healthy subject who performed cyclic knee flexion-extension. Cartilage contact for the subject was assessed by measuring the overlap between articular cartilage surfaces. Model-based tracking was able to track tibiofemoral angles and translations with precisions less than 0.8° and 0.5mm. These precisions resulted in an uncertainty of less than 0.5mm in cartilage contact location. Dynamic SPGR-VIPR imaging can accurately assess in vivo knee kinematics and cartilage contact during voluntary knee motion performed in a MRI scanner. This technology could facilitate the quantitative investigation of links between joint mechanics and the development of osteoarthritis.

  17. Multisensory integration of dynamic emotional faces and voices: method for simultaneous EEG-fMRI measurements

    Directory of Open Access Journals (Sweden)

    Patrick David Schelenz

    2013-11-01

    Full Text Available Combined EEG-fMRI analysis correlates time courses from single electrodes or independent EEG components with the hemodynamic response. Implementing information from only one electrode, however, may miss relevant information from complex electrophysiological networks. Component based analysis, in turn, depends on a priori knowledge of the signal topography. Complex designs such as studies on multisensory integration of emotions investigate subtle differences in distributed networks based on only a few trials per condition. Thus, they require a sensitive and comprehensive approach which does not rely on a-priori knowledge about the underlying neural processes. In this pilot study, feasibility and sensitivity of source localization-driven analysis for EEG-fMRI was tested using a multisensory integration paradigm. Dynamic audiovisual stimuli consisting of emotional talking faces and pseudowords with emotional prosody were rated in a delayed response task. The trials comprised affectively congruent and incongruent displays.In addition to event-locked EEG and fMRI analyses, induced oscillatory EEG responses at estimated cortical sources and in specific temporo-spectral windows were correlated with the corresponding BOLD responses. EEG analysis showed high data quality with less than 10% trial rejection. In an early time window, alpha oscillations were suppressed in bilateral occipital cortices and fMRI analysis confirmed high data quality with reliable activation in auditory, visual and frontal areas to the presentation of multisensory stimuli. In line with previous studies, we obtained reliable correlation patterns for event locked occipital alpha suppression and BOLD signal time course.Our results suggest a valid methodological approach to investigate complex stimuli using the present source localization driven method for EEG-fMRI. This novel procedure may help to investigate combined EEG-fMRI data from novel complex paradigms with high spatial and

  18. Multisensory integration of dynamic emotional faces and voices: method for simultaneous EEG-fMRI measurements.

    Science.gov (United States)

    Schelenz, Patrick D; Klasen, Martin; Reese, Barbara; Regenbogen, Christina; Wolf, Dhana; Kato, Yutaka; Mathiak, Klaus

    2013-01-01

    Combined EEG-fMRI analysis correlates time courses from single electrodes or independent EEG components with the hemodynamic response. Implementing information from only one electrode, however, may miss relevant information from complex electrophysiological networks. Component based analysis, in turn, depends on a priori knowledge of the signal topography. Complex designs such as studies on multisensory integration of emotions investigate subtle differences in distributed networks based on only a few trials per condition. Thus, they require a sensitive and comprehensive approach which does not rely on a-priori knowledge about the underlying neural processes. In this pilot study, feasibility and sensitivity of source localization-driven analysis for EEG-fMRI was tested using a multisensory integration paradigm. Dynamic audiovisual stimuli consisting of emotional talking faces and pseudowords with emotional prosody were rated in a delayed response task. The trials comprised affectively congruent and incongruent displays. In addition to event-locked EEG and fMRI analyses, induced oscillatory EEG responses at estimated cortical sources and in specific temporo-spectral windows were correlated with the corresponding BOLD responses. EEG analysis showed high data quality with less than 10% trial rejection. In an early time window, alpha oscillations were suppressed in bilateral occipital cortices and fMRI analysis confirmed high data quality with reliable activation in auditory, visual and frontal areas to the presentation of multisensory stimuli. In line with previous studies, we obtained reliable correlation patterns for event locked occipital alpha suppression and BOLD signal time course. Our results suggest a valid methodological approach to investigate complex stimuli using the present source localization driven method for EEG-fMRI. This novel procedure may help to investigate combined EEG-fMRI data from novel complex paradigms with high spatial and temporal

  19. Correlation of preoperative MRI and intraoperative 3D ultrasound to measure brain tissue shift

    Science.gov (United States)

    Gobbi, David G.; Lee, Belinda K. H.; Peters, Terence M.

    2001-05-01

    B-Mode ultrasound is often used during neurosurgery to provide intra-operative images of the brain though a craniotomy, but the use of 3D ultrasound during surgery is still in its infancy. We have developed a system that provides real-time freehand 3D ultrasound reconstruction at a reduced resolution. The reconstruction proceeds incrementally and the 3D image is overlayed, via a computer, on a pre-operative 3D MRI scan. This provides the operator with the necessary feedback to maintain a constant freehand sweep-rate, and also ensures that the sweep covers the desired anatomical volume. All of the ultrasound video frames are buffered, and a full-resolution, compounded reconstruction proceeds once the manual sweep is complete. We have also developed tools for manual tagging of homologous landmarks in the 3D MRI and 3D ultrasound volumes that use a piecewise cubic approximation of thin-plate spline interpolation to achieve interactive nonlinear registration and warping of the MRI volume to the ultrasound volume: Each time a homologous point-pair is identified by the use, the image of the warped MRI is updated on the computer screen after less than 0.5 s.

  20. A New Similarity Measure for Non-Local Means Filtering of MRI Images

    CERN Document Server

    Dolui, Sudipto; Patarroyo, Iván C Salgado; Michailovich, Oleg V

    2011-01-01

    The acquisition of MRI images offers a trade-off in terms of acquisition time, spatial/temporal resolution and signal-to-noise ratio (SNR). Thus, for instance, increasing the time efficiency of MRI often comes at the expense of reduced SNR. This, in turn, necessitates the use of post-processing tools for noise rejection, which makes image de-noising an indispensable component of computer assistance diagnosis. In the field of MRI, a multitude of image de-noising methods have been proposed hitherto. In this paper, the application of a particular class of de-noising algorithms - known as non-local mean (NLM) filters - is investigated. Such filters have been recently applied for MRI data enhancement and they have been shown to provide more accurate results as compared to many alternative de-noising algorithms. Unfortunately, virtually all existing methods for NLM filtering have been derived under the assumption of additive white Gaussian (AWG) noise contamination. Since this assumption is known to fail at low val...

  1. Analysis of group ICA-based connectivity measures from fMRI: application to Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Shanshan Li

    Full Text Available Functional magnetic resonance imaging (fMRI is a powerful tool for the in vivo study of the pathophysiology of brain disorders and disease. In this manuscript, we propose an analysis stream for fMRI functional connectivity data and apply it to a novel study of Alzheimer's disease. In the first stage, spatial independent component analysis is applied to group fMRI data to obtain common brain networks (spatial maps and subject-specific mixing matrices (time courses. In the second stage, functional principal component analysis is utilized to decompose the mixing matrices into population-level eigenvectors and subject-specific loadings. Inference is performed using permutation-based exact logistic regression for matched pairs data. The method is applied to a novel fMRI study of Alzheimer's disease risk under a verbal paired associates task. We found empirical evidence of alternative ICA-based metrics of connectivity when comparing subjects evidencing mild cognitive impairment relative to carefully matched controls.

  2. Measurement of distinctive features of cortical spreading depolarizations with different MRI contrasts

    NARCIS (Netherlands)

    Umesh Rudrapatna, S.; Hamming, Arend M.; Wermer, Marieke J H; van der Toorn, A; Dijkhuizen, Rick M.

    2015-01-01

    Growing clinical evidence suggests critical involvement of spreading depolarizations (SDs) in the pathophysiology of neurological disorders such as migraine and stroke. MRI provides powerful tools to detect and assess co-occurring cerebral hemodynamic and cellular changes during SDs. This study

  3. Measurement of distinctive features of cortical spreading depolarizations with different MRI contrasts

    NARCIS (Netherlands)

    Umesh Rudrapatna, S.; Hamming, Arend M.; Wermer, Marieke J H; van der Toorn, A; Dijkhuizen, Rick M.

    2015-01-01

    Growing clinical evidence suggests critical involvement of spreading depolarizations (SDs) in the pathophysiology of neurological disorders such as migraine and stroke. MRI provides powerful tools to detect and assess co-occurring cerebral hemodynamic and cellular changes during SDs. This study repo

  4. PHYCAA: Data-driven measurement and removal of physiological noise in BOLD fMRI

    DEFF Research Database (Denmark)

    Churchill, Nathan W.; Yourganov, Grigori; Spring, Robyn

    2012-01-01

    challenge for identifying and removing such artifact. This paper presents a multivariate, data-driven method for the characterization and removal of physiological noise in fMRI data, termed PHYCAA (PHYsiological correction using Canonical Autocorrelation Analysis). The method identifies high frequency...

  5. Sampling rate dependence of correlation at long time lags in BOLD fMRI measurements on humans and gel phantoms.

    Science.gov (United States)

    Mikkelsen, Kaare B; Lund, Torben E

    2013-01-01

    The aim of this study is to investigate the effects of sampling rate on Hurst exponents derived from Blood Oxygenation Level Dependent functional Magnetic Resonance Imaging (BOLD fMRI) resting state time series. fMRI measurements were performed on 2 human subjects and a selection of gel phantoms. From these, Hurst exponents were calculated. It was found that low sampling rates induced non-trivial exponents at sharp material transitions, and that Hurst exponents of human measurements had a strong TR-dependence. The findings are compared to theoretical considerations regarding the fractional Gaussian noise model and resampling, and it is found that the implications are problematic. This result should have a direct influence on the way future studies of low-frequency variation in BOLD fMRI data are conducted, especially if the fractional Gaussian noise model is considered. We recommend either using a different model (examples of such are referenced in the conclusion), or standardizing experimental procedures along an optimal sampling rate.

  6. In vitro validation of flow measurements in an aortic nitinol stent graft by velocity-encoded MRI

    Energy Technology Data Exchange (ETDEWEB)

    Rengier, Fabian, E-mail: f.rengier@dkfz.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); German Cancer Research Center (dkfz) Heidelberg, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Delles, Michael, E-mail: delles@kit.edu [Karlsruhe Institute of Technology (KIT), Department of Informatics, Institute for Anthropomatics, Adenauerring 2, 76131 Karlsruhe (Germany); Weber, Tim Frederik, E-mail: Tim.Weber@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Boeckler, Dittmar, E-mail: dboeckler@me.com [University Hospital Heidelberg, Department of Vascular and Endovascular Surgery, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Ley, Sebastian, E-mail: ley@gmx.net [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich, E-mail: Hans-Ulrich.Kauczor@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); Tengg-Kobligk, Hendrik von, E-mail: h.vontengg@dkfz.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Im Neuenheimer Feld 110, 69120 Heidelberg (Germany); German Cancer Research Center (dkfz) Heidelberg, Department of Radiology, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

    2011-10-15

    Purpose: To validate flow measurements within an aortic nickel-titanium (nitinol) stent graft using velocity-encoded cine magnetic resonance imaging (VEC MRI) and to assess intraobserver agreement of repeated flow measurements. Materials and methods: An elastic tube phantom mimicking the descending aorta was developed with the possibility to insert an aortic nitinol stent graft. Different flow patterns (constant, sinusoidal and pulsatile aortic flow) were applied by a gear pump. A two-dimensional phase-contrast sequence was used to acquire VEC perpendicular cross-sections at six equidistant levels along the phantom. Each acquisition was performed twice with and without stent graft, and each dataset was analysed twice by the same reader. The percental difference of the measured flow volume to the gold standard (pump setting) was defined as the parameter for accuracy. Furthermore, the intraobserver agreement was assessed. Results: Mean accuracy of flow volume measurements was -0.45 {+-} 1.63% without stent graft and -0.18 {+-} 1.45% with stent graft. Slightly lower accuracy was obtained for aortic flow both without (-2.31%) and with (-1.29%) stent graft. Accuracy was neither influenced by the measurement position nor by repeated acquisitions. There was significant intraobserver agreement with an intraclass correlation coefficient of 0.87 (without stent graft, p < 0.001) and 0.80 (with stent graft, p < 0.001). The coefficient of variance was 0.25% without stent graft and 0.28% with stent graft. Conclusion: This study demonstrated high accuracy and excellent intraobserver agreement of flow measurements within an aortic nitinol stent graft using VEC MRI. VEC MRI may give new insights into the haemodynamic consequences of endovascular aortic repair.

  7. Measurement of the square measure of the pharynx and the positional diagnosis of airway obstruction during obstructive sleep apnea syndrome by dynamic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ozuki, Taizo; Ohkubo, Yasuo; Abe, Kimihiko [Tokyo Medical Coll. (Japan)

    2000-11-01

    The purpose of this study was to apply dynamic MRI for the positional diagnosis of airway obstruction during snoring and sleep apnea and to compare the apnea hypopnea index (AHI) and the square measure of the pharynx obtained before and after laser-assisted uvula-palate-pharyngoplasty (LAUP). From December 1997 to October 1998, dynamic MRI and overnight monitoring were performed at the hospital of Tokyo Medical University on 42 patients who complained of snoring and symptoms related to sleep apnea syndrome (SAS). Of the 42 patients, four exhibited collapse at the position of the soft palate (soft palate type) as diagnosed by dynamic MRI, and four exhibited collapse at the position of the soft palate as well as the tongue (complex type). LAUP was performed on these eight patients with obstructive SAS (OSAS). After LAUP, the AHI of these eight patients with OSAS decreased significantly (p<0.05). The square measure of the pharynx of these eight patients was increased (p<0.01). The AHI of all four patients with soft-palate obstruction decreased, and the square measure of the pharynx of three of these four patients increased. The AHI of three of four patients with the complex type decreased, while the square measure of the pharynx of two of these four patients increased. (author)

  8. The value of MRI iniIdiopathic tarsal tunnel syndrome by measuring the cross-sectional area of tarsal tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Jung; Jeong, Yu Mi; Lee, Sheen Woo; Choi Seung; Kim, Jeong Ho; Park, Hong Gi [Gachon University, Gil Hospital, Incheon (Korea, Republic of)

    2015-03-15

    The purpose of this study was to evaluate the use of MRI as a diagnostic test in tarsal tunnel syndrome. There are no published reports with this aim and no diagnostic standard for idiopathic tarsal tunnel syndrome (TTS) using imaging modalities. We retrospectively searched our Picture Archiving and Communication System data and medical records to identify patients who were clinically and electomyographically diagnosed with idiopathic TTS without space-occupying lesion on MRI. Twenty five patients were included in the patient group. Another twenty-five patients who underwent ankle MRI for Achilles tendon disease were selected and included in the control group. Cross-sectional areas (CSA) of tarsal tunnel were manually measured independently by two radiologists who were blinded to clinical and surgical results, using three-dimensional reconstruction software in our hospital. Measurements were done on axial images at three levels (level 1, tibiotalar joint level; level 2, medial malleolar tip level; level 3, sustentaculum tali level). Patient and control group data were statistically analyzed by the Mann-Whitney test. The mean values of CSA at levels 1, 2, and 3 of the tarsal tunnel were 87.8 mm2, 98.2 mm2, and 105.2 mm2, respectively in the patient group; and 100.0 mm2, 113.8 mm2, and 127.9 mm2 in the control group, respectively, in reader 1; and 86.2 mm2, 97.6 mm2, 105.2 mm2, respectively in the patient group; and 99.7 mm2, 112.3 mm2, 124.4 mm2, respectively, in the control group, in reader 2. The mean CSA in the patient group was significantly less than that of the control group at all three levels (p < 0.05). Intra-class correlation coefficient value between reader 1 and reader 2 were 0.98 in group 1, and 0.97 in group 2, respectively. MRI can be helpful in the assessment of idiopathic tarsal tunnel syndrome. CSA measurements of tarsal tunnel at each level may predict TTS even though there are no space occupying lesions in the tarsal tunnel on MRI.

  9. Reliability and agreement of adipose tissue fat fraction measurements with water-fat MRI in patients with manifest cardiovascular disease.

    Science.gov (United States)

    Franssens, Bas T; Eikendal, Anouk L; Leiner, Tim; van der Graaf, Yolanda; Visseren, Frank L J; Hoogduin, J M

    2016-01-01

    The supraclavicular fat depot is known for brown adipose tissue presence. To unravel adipose tissue physiology and metabolism, high quality and reproducible imaging is required. In this study we quantified the reliability and agreement of MRI fat fraction measurements in supraclavicular and subcutaneous adipose tissue of 25 adult patients with clinically manifest cardiovascular disease. MRI fat fraction measurements were made under ambient temperature conditions using a vendor supplied mDixon chemical-shift water-fat multi-echo pulse sequence at 1.5 T field strength. Supraclavicular fat fraction reliability (intraclass correlation coefficientagreement , ICCagreement ) was 0.97 for test-retest, 0.95 for intra-observer and 0.56 for inter-observer measurements, which increased to 0.88 when ICCconsistency was estimated. Supraclavicular fat fraction agreement displayed mean differences of 0.5% (limit of agreement (LoA) -1.7 to 2.6) for test-retest, -0.5% (LoA -2.9 to 2.0) for intra-observer and 5.6% (LoA 0.4 to 10.8) for inter-observer measurements. Median fat fraction in supraclavicular adipose tissue was 82.5% (interquartile range (IQR) 78.6-84.0) and 89.7% (IQR 87.2-91.5) in subcutaneous adipose tissue (p fat MRI has good reliability and agreement to measure adipose tissue fat fraction in patients with manifest cardiovascular disease. These findings enable research on determinants of fat fraction and enable longitudinal monitoring of fat fraction within adipose tissue depots. Interestingly, even in adult patients with manifest cardiovascular disease, supraclavicular adipose tissue has a lower fat fraction compared with subcutaneous adipose tissue, suggestive of distinct morphologic characteristics, such as brown adipose tissue.

  10. Relationship between saccadic eye movements and cortical activity as measured by fMRI

    DEFF Research Database (Denmark)

    Kimmig, H.; Greenlee, M.W.; Gondan, Matthias;

    2001-01-01

    quantitative changes in cortical activity associated with qualitative changes in the saccade task for comparable levels of saccadic activity. All experiments required the simultaneous acquisition of eye movement and fMRI data. For this purpose we used a new high-resolution limbus-tracking technique......We investigated the quantitative relationship between saccadic activity (as reflected in frequency of occurrence and amplitude of saccades) and blood oxygenation level dependent (BOLD) changes in the cerebral cortex using functional magnetic resonance imaging (fMRI). Furthermore, we investigated....... The latter finding is taken to indicate a more demanding cortical processing in the "anti" task than the "pro" task, which could explain the observed difference in BOLD activation. We hold that a quantitative analysis of saccade parameters (especially saccade frequency and latency) is important...

  11. MRI Slice Segmentation and 3D Modelling of Temporomandibular Joint Measured by Microscopic Coil

    Science.gov (United States)

    Smirg, O.; Liberda, O.; Smekal, Z.; Sprlakova-Pukova, A.

    2012-01-01

    The paper focuses on the segmentation of magnetic resonance imaging (MRI) slices and 3D modelling of the temporomandibular joint disc in order to help physicians diagnose patients with dysfunction of the temporomandibular joint (TMJ). The TMJ is one of the most complex joints in the human body. The most common joint dysfunction is due to the disc. The disc is a soft tissue, which in principle cannot be diagnosed by the CT method. Therefore, a 3D model is made from the MRI slices, which can image soft tissues. For the segmentation of the disc in individual slices a new method is developed based on spatial distribution and anatomical TMJ structure with automatic thresholding. The thresholding is controlled by a genetic algorithm. The 3D model is realized using the marching cube method.

  12. Peripheral nerve MRI: precision and reproducibility of T2*-derived measurements at 3.0-T. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Tagliafico, Alberto [University of Genoa, Institute of Anatomy, Department of Experimental Medicine, Genoa (Italy); Bignotti, Bianca; Martinoli, Carlo [University of Genoa, Radiology Department, Genoa, Genova (Italy); Tagliafico, Giulio [CNR-IMATI, Consiglio Nazionale delle Ricerche, Istituto di Matematica Applicata e Tecnologie Informatiche, Genova (Italy)

    2015-05-01

    To prospectively evaluate the precision and reproducibility of T2*-derived measurements of the peripheral nerves. The study was approved by the local ethics committee and written informed consent was obtained. Bilateral upper and lower limb MRI examination was performed in 40 healthy subjects on a 3.0-T scanner. MRI protocol included T1-turbo spin-echo, T2-turbo spin-echo with fat suppression, and multiecho gradient recalled echo. Measurements of T2* times on T2* maps at different anatomical levels were performed. Three authors measured independently and in different sessions at baseline and after 4 weeks. Non-parametric tests and Bland-Altman statistics were used. Minimum and maximum percentage variability were 10 % and 19 % for T2* (84-91 % of reproducibility). Maximum values of minimum detectable differences between limbs was 16 % (with 95 % CI: 2-37). Intra- and inter-observer agreement of the three radiologists for T2* was considered good. Evaluating the combined influence of the observer and of the repeated measurements the reproducibility was 87-98 %. T2* measurement of the peripheral nerves is precise and reproducible. The healthy contralateral side can be used as an internal control. Variations in T2* values up to 16 % have to be considered. (orig.)

  13. MRI and MRS of human brain tumors.

    Science.gov (United States)

    Hou, Bob L; Hu, Jiani

    2009-01-01

    The purpose of this chapter is to provide an introduction to magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of human brain tumors, including the primary applications and basic terminology involved. Readers who wish to know more about this broad subject should seek out the referenced books (1. Tofts (2003) Quantitative MRI of the brain. Measuring changes caused by disease. Wiley; Bradley and Stark (1999) 2. Magnetic resonance imaging, 3rd Edition. Mosby Inc; Brown and Semelka (2003) 3. MRI basic principles and applications, 3rd Edition. Wiley-Liss) or reviews (4. Top Magn Reson Imaging 17:127-36, 2006; 5. JMRI 24:709-724, 2006; 6. Am J Neuroradiol 27:1404-1411, 2006).MRI is the most popular means of diagnosing human brain tumors. The inherent difference in the magnetic resonance (MR) properties of water between normal tissues and tumors results in contrast differences on the image that provide the basis for distinguishing tumors from normal tissues. In contrast to MRI, which provides spatial maps or images using water signals of the tissues, proton MRS detects signals of tissue metabolites. MRS can complement MRI because the observed MRS peaks can be linked to inherent differences in biochemical profiles between normal tissues and tumors.The goal of MRI and MRS is to characterize brain tumors, including tumor core, edge, edema, volume, types, and grade. The commonly used brain tumor MRI protocol includes T2-weighted images and T1-weighted images taken both before and after the injection of a contrast agent (typically gadolinium: Gd). The commonly used MRS technique is either point-resolved spectroscopy (PRESS) or stimulated echo acquisition mode (STEAM).

  14. Colon wall motility: comparison of novel quantitative semi-automatic measurements using cine MRI.

    Science.gov (United States)

    Hoad, C L; Menys, A; Garsed, K; Marciani, L; Hamy, V; Murray, K; Costigan, C; Atkinson, D; Major, G; Spiller, R C; Taylor, S A; Gowland, P A

    2016-03-01

    Recently, cine magnetic resonance imaging (MRI) has shown promise for visualizing movement of the colonic wall, although assessment of data has been subjective and observer dependent. This study aimed to develop an objective and semi-automatic imaging metric of ascending colonic wall movement, using image registration techniques. Cine balanced turbo field echo MRI images of ascending colonic motility were acquired over 2 min from 23 healthy volunteers (HVs) at baseline and following two different macrogol stimulus drinks (11 HVs drank 1 L and 12 HVs drank 2 L). Motility metrics derived from large scale geometric and small scale pixel movement parameters following image registration were developed using the post ingestion data and compared to observer grading of wall motion. Inter and intra-observer variability in the highest correlating metric was assessed using Bland-Altman analysis calculated from two separate observations on a subset of data. All the metrics tested showed significant correlation with the observer rating scores. Line analysis (LA) produced the highest correlation coefficient of 0.74 (95% CI: 0.55-0.86), p cine MRI registered data provides a quick, accurate and non-invasive method to detect wall motion within the ascending colon following a colonic stimulus in the form of a macrogol drink. © 2015 John Wiley & Sons Ltd.

  15. Impaired sensory processing measured by functional MRI in Bipolar disorder manic and depressed mood states.

    Science.gov (United States)

    Shaffer, Joseph J; Johnson, Casey P; Fiedorowicz, Jess G; Christensen, Gary E; Wemmie, John A; Magnotta, Vincent A

    2017-07-03

    Bipolar disorder is characterized by recurring episodes of depression and mania. Defining differences in brain function during these states is an important goal of bipolar disorder research. However, few imaging studies have directly compared brain activity between bipolar mood states. Herein, we compare functional magnetic resonance imaging (fMRI) responses during a flashing checkerboard stimulus between bipolar participants across mood states (euthymia, depression, and mania) in order to identify functional differences between these states. 40 participants with bipolar I disorder and 33 healthy controls underwent fMRI during the presentation of the stimulus. A total of 23 euthymic-state, 16 manic-state, 15 depressed-state, and 32 healthy control imaging sessions were analyzed in order to compare functional activation during the stimulus between mood states and with healthy controls. A reduced response was identified in the visual cortex in both the depressed and manic groups compared to euthymic and healthy participants. Functional differences between bipolar mood states were also observed in the cerebellum, thalamus, striatum, and hippocampus. Functional differences between mood states occurred in several brain regions involved in visual and other sensory processing. These differences suggest that altered visual processing may be a feature of mood states in bipolar disorder. The key limitations of this study are modest mood-state group size and the limited temporal resolution of fMRI which prevents the segregation of primary visual activity from regulatory feedback mechanisms.

  16. Perfusion and vascular permeability: basic concepts and measurement in DCE-CT and DCE-MRI.

    Science.gov (United States)

    Cuenod, C A; Balvay, D

    2013-12-01

    The microvascular network formed by the capillaries supplies the tissues and permits their function. It provides a considerable surface area for exchanges between blood and tissues. All pathological conditions cause changes in the microcirculation. These changes can be used as imaging biomarkers for the diagnosis of lesions and optimisation of treatment. Among the many imaging techniques developed to study the microcirculation, the analysis of the tissue kinetics of intravenously injected contrast agents is the most widely used, either as positive enhancement for CT, T1-weighted MRI and ultrasound - dynamic contrast-enhanced-imaging (DCE-imaging) - or negative enhancement in T2*-weighted brain MRI - dynamic susceptibility contrast-MRI (DSC-MRI) -. Acquisition involves an injection of contrast agent during the acquisition of a dynamic series of images on a zone of interest. These kinetics may be analyzed visually, to define qualitative criteria, or with software using mathematical modelling, to extract quantitative physiological parameters. The results depend on the acquisition conditions (type of imaging device, imaging mode, frequency and total duration of acquisition), the type of contrast agent, the data pre-processing (motion correction, conversion of the signal into concentration) and the data analysis method. Because of these multiple choices it is necessary to understand the physiological processes involved and understand the advantages and limits of each strategy.

  17. Longitudinal measurements of MRI-T2 in boys with Duchenne muscular dystrophy: effects of age and disease progression.

    Science.gov (United States)

    Willcocks, R J; Arpan, I A; Forbes, S C; Lott, D J; Senesac, C R; Senesac, E; Deol, J; Triplett, W T; Baligand, C; Daniels, M J; Sweeney, H L; Walter, G A; Vandenborne, K

    2014-05-01

    Duchenne muscular dystrophy (DMD) is characterized by an increased muscle damage and progressive replacement of muscle by noncontractile tissue. Both of these pathological changes can lengthen the MRI transverse proton relaxation time (T2). The current study measured longitudinal changes in T2 and its distribution in the lower leg of 16 boys with DMD (5-13years, 15 ambulatory) and 15 healthy controls (5-13years). These muscles were chosen to allow extended longitudinal monitoring, due to their slow progression compared with proximal muscles in DMD. In the soleus muscle of boys with DMD, T2 and the percentage of pixels with an elevated T2 (⩾2SD above control mean T2) increased significantly over 1year and 2years, while the width of the T2 histogram increased over 2years. Changes in soleus T2 variables were significantly greater in 9-13years old compared with 5-8years old boys with DMD. Significant correlations between the change in all soleus T2 variables over 2years and the change in functional measures over 2years were found. MRI measurement of muscle T2 in boys with DMD is sensitive to disease progression and shows promise as a clinical outcome measure.

  18. MRI characterization of temporal lobe epilepsy using rapidly measurable spatial indices with hemisphere asymmetries and gender features

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Siddhartha; Chakrabarti, Nilkanta [University of Calcutta, Department of Physiology and UGC-CPEPA Centre for ' ' Electro-physiological and Neuro-imaging studies including Mathematical Modelling' ' , Kolkata (India); Sarkar, Sudipta; Chakraborty, Sumit; Basu, Swadhapriya [IPGME and R, SSKM Hospital, Department of Radiodiagnosis, Kolkata (India); Mulpuru, Sai Krishna [National Brain Research Centre, National Neuro-Imaging Facility, Manesar (India); Tiwary, Basant K. [Pondicherry University, Centre for Bioinformatics, School of Life Sciences, Pondicherry (India); Roy, Prasun Kumar [National Brain Research Centre, Computational Neuroimaging Division, Manesar (India); National Brain Research Centre, Clinical Neuroscience Unit, Gurgaon (India)

    2015-09-15

    The paucity of morphometric markers for hemispheric asymmetries and gender variations in hippocampi and amygdalae in temporal lobe epilepsy (TLE) calls for better characterization of TLE by finding more useful prognostic MRI parameter(s). T1-weighted MRI (3 T) morphometry using multiple parameters of hippocampus-parahippocampus (angular and linear measures, volumetry) and amygdalae (volumetry) including their hemispheric asymmetry indices (AI) were evaluated in both genders. The cutoff values of parameters were statistically estimated from measurements of healthy subjects to characterize TLE (57 patients, 55 % male) alterations. TLE had differential categories with hippocampal atrophy, parahippocampal angle (PHA) acuteness, and several other parametric changes. Bilateral TLE categories were much more prevalent compared to unilateral TLE categories. Female patients were considerably more disposed to bilateral TLE categories than male patients. Male patients displayed diverse categories of unilateral abnormalities. Few patients (both genders) had combined bilateral appearances of hippocampal atrophy, amygdala atrophy, PHA acuteness, and increase in hippocampal angle (HA) where medial distance ratio (MDR) varied among genders. TLE had gender-specific and hemispheric dominant alterations in AI of parameters. Maximum magnitude of parametric changes in TLE includes (a) AI increase in HA of both genders, (b) HA increase (bilateral) in female patients, and (c) increase in ratio of amygdale/hippocampal volume (unilateral, right hemispheric), and AI decrease in MDR, in male patients. Multiparametric MRI studies of hippocampus and amygdalae, including their hemispheric asymmetry, underscore better characterization of TLE. Rapidly measurable single-slice parameters (HA, PHA, MDR) can readily delineate TLE in a time-constrained clinical setting, which contrasts with customary three-dimensional hippocampal volumetry that requires many slice computation. (orig.)

  19. MRI characterization of temporal lobe epilepsy using rapidly measurable spatial indices with hemisphere asymmetries and gender features.

    Science.gov (United States)

    Datta, Siddhartha; Sarkar, Sudipta; Chakraborty, Sumit; Mulpuru, Sai Krishna; Basu, Swadhapriya; Tiwary, Basant K; Chakrabarti, Nilkanta; Roy, Prasun Kumar

    2015-09-01

    The paucity of morphometric markers for hemispheric asymmetries and gender variations in hippocampi and amygdalae in temporal lobe epilepsy (TLE) calls for better characterization of TLE by finding more useful prognostic MRI parameter(s). T1-weighted MRI (3 T) morphometry using multiple parameters of hippocampus-parahippocampus (angular and linear measures, volumetry) and amygdalae (volumetry) including their hemispheric asymmetry indices (AI) were evaluated in both genders. The cutoff values of parameters were statistically estimated from measurements of healthy subjects to characterize TLE (57 patients, 55% male) alterations. TLE had differential categories with hippocampal atrophy, parahippocampal angle (PHA) acuteness, and several other parametric changes. Bilateral TLE categories were much more prevalent compared to unilateral TLE categories. Female patients were considerably more disposed to bilateral TLE categories than male patients. Male patients displayed diverse categories of unilateral abnormalities. Few patients (both genders) had combined bilateral appearances of hippocampal atrophy, amygdala atrophy, PHA acuteness, and increase in hippocampal angle (HA) where medial distance ratio (MDR) varied among genders. TLE had gender-specific and hemispheric dominant alterations in AI of parameters. Maximum magnitude of parametric changes in TLE includes (a) AI increase in HA of both genders, (b) HA increase (bilateral) in female patients, and (c) increase in ratio of amygdale/hippocampal volume (unilateral, right hemispheric), and AI decrease in MDR, in male patients. Multiparametric MRI studies of hippocampus and amygdalae, including their hemispheric asymmetry, underscore better characterization of TLE. Rapidly measurable single-slice parameters (HA, PHA, MDR) can readily delineate TLE in a time-constrained clinical setting, which contrasts with customary three-dimensional hippocampal volumetry that requires many slice computation.

  20. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: an international multicenter reliability study using computerized MRI erosion volume measurements

    DEFF Research Database (Denmark)

    Bird, P; Ejbjerg, B; McQueen, F

    2003-01-01

    Scoring erosions on magnetic resonance imaging (MRI) is one method of estimating damage in patients with rheumatoid arthritis (RA), but it has limitations. The aim of this pilot study was to assess the feasibility and inter-reader reliability of computer assisted erosion volume estimation...... with metacarpophalangeal (MCP) joints 2 to 5 of the dominant hand included in the field of view. Three readers were instructed to grade MCP 2 and 3 using the OMERACT grading system and then to measure the erosion volume of the same joints using OSIRIS software. The inter-reader reliability of the grading method...

  1. 1D.09: APPLICABILITY OF MEASUREMENT OF RENAL PERFUSION USING 1.5 TESLA MRI ARTERIAL SPIN LABELLING.

    Science.gov (United States)

    Kistner, I; Ott, C; Jumar, A; Friedrich, S; Grosso, R; Siegl, C; Schmieder, R E; Janka, R

    2015-06-01

    Renal perfusion is a key parameter of kidney function and the decrement of renal perfusion is a marker of target organ damage caused by hypertension. Detecting these changes in renal perfusion could help to manage antihypertensive therapy and evaluate patients[Combining Acute Accent] prognosis. Measurement of renal perfusion by MRI arterial spin labelling (ASL) is a non-invasive and non-time-consuming method without the need to inject any contrast agent. This study examined reproducibility of renal perfusion measured by 1.5 Tesla MRI. Renal perfusion was measured by ASL technique using an 1.5 Tesla MRI scanner. Subjects were scanned 3 times at two different days in an interval of two weeks to assess the test-retest reproducibility. Renal perfusion was automatically calculated for the cortex and medulla of the kidney by dedicated software. 14 patients were included with mean age 48.9 ± 12.7 and mean office blood pressure 132 ± 16/82 ± 10mmHg and estimated glomerular filtration rate> 60 ml/min/1.73m. The change of the mean total, cortical and medullary renal perfusion from the first examination to the second examination was 0.37 ± 13/0.62 ± 18/0.00 ± 12 ml/min/100 g kidney weight (p = 0.915/p = 0.898/p = 0.998), respectively. There was also no significant difference between the three renal perfusion measurements at one time point. For clinical trials these data indicate that to detect a 5% (10%) difference of cortical renal perfusion due to an intervention (vs placebo) only 38 (14) patients are required in face of the observed standard deviation for the change in renal perfusion. The inter and intra-session reproducibility of cortical renal perfusion assessed by MRI ASL 1.5 Tesla is excellent and small study cohorts can be used for examination of renal perfusion.

  2. Efficient solution methodology for calibrating the hemodynamic model using functional Magnetic Resonance Imaging (fMRI) measurements

    KAUST Repository

    Zambri, Brian

    2015-11-05

    Our aim is to propose a numerical strategy for retrieving accurately and efficiently the biophysiological parameters as well as the external stimulus characteristics corresponding to the hemodynamic mathematical model that describes changes in blood flow and blood oxygenation during brain activation. The proposed method employs the TNM-CKF method developed in [1], but in a prediction/correction framework. We present numerical results using both real and synthetic functional Magnetic Resonance Imaging (fMRI) measurements to highlight the performance characteristics of this computational methodology. © 2015 IEEE.

  3. Relationship between saccadic eye movements and cortical activity as measured by fMRI

    DEFF Research Database (Denmark)

    Kimmig, H.; Greenlee, M.W.; Gondan, Matthias;

    2001-01-01

    quantitative changes in cortical activity associated with qualitative changes in the saccade task for comparable levels of saccadic activity. All experiments required the simultaneous acquisition of eye movement and fMRI data. For this purpose we used a new high-resolution limbus-tracking technique...... that repeated processing of saccades is integrated over time in the BOLD response. In contrast, there was no comparable BOLD change with variation of saccade amplitude. This finding speaks for a topological rather than activity-dependent coding of saccade amplitudes in most cortical regions. In the experiments...

  4. Chest MRI

    Science.gov (United States)

    Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI ... healthy enough to filter the contrast. During the MRI, the person who operates the machine will watch ...

  5. Cortical phase changes measured using 7-T MRI in subjects with subjective cognitive impairment, and their association with cognitive function.

    Science.gov (United States)

    van Rooden, Sanneke; Buijs, Mathijs; van Vliet, Marjolein E; Versluis, Maarten J; Webb, Andrew G; Oleksik, Ania M; van de Wiel, Lotte; Middelkoop, Huub A M; Blauw, Gerard Jan; Weverling-Rynsburger, Annelies W E; Goos, Jeroen D C; van der Flier, Wiesje M; Koene, Ted; Scheltens, Philip; Barkhof, Frederik; van de Rest, Ondine; Slagboom, P Eline; van Buchem, Mark A; van der Grond, Jeroen

    2016-09-01

    Studies have suggested that, in subjects with subjective cognitive impairment (SCI), Alzheimer's disease (AD)-like changes may occur in the brain. Recently, an in vivo study has indicated the potential of ultra-high-field MRI to visualize amyloid-beta (Aβ)-associated changes in the cortex in patients with AD, manifested by a phase shift on T2 *-weighted MRI scans. The main aim of this study was to investigate whether cortical phase shifts on T2 *-weighted images at 7 T in subjects with SCI can be detected, possibly implicating the deposition of Aβ plaques and associated iron. Cognitive tests and T2 *-weighted scans using a 7-T MRI system were performed in 28 patients with AD, 18 subjects with SCI and 27 healthy controls (HCs). Cortical phase shifts were measured. Univariate general linear modeling and linear regression analysis were used to assess the association between diagnosis and cortical phase shift, and between cortical phase shift and the different neuropsychological tests, adjusted for age and gender. The phase shift (mean, 1.19; range, 1.00-1.35) of the entire cortex in AD was higher than in both SCI (mean, 0.85; range, 0.73-0.99; p WMS) and cortical phase shift (β = -0.544, p = 0.007). The major finding of this study is that, in subjects with SCI, an increased cortical phase shift measured at high field is associated with a poorer memory performance, although, as a group, subjects with SCI do not show an increased phase shift compared with HCs. This increased cortical phase shift related to memory performance may contribute to the understanding of SCI as it is still unclear whether SCI is a sign of pre-clinical AD. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Correlation of intra-articular osseous measurements with posterior cruciate ligament length on MRI scans.

    LENUS (Irish Health Repository)

    Orakzai, S H

    2010-01-01

    Six patients with a clinical diagnosis of chronic posterior cruciate ligament (PCL) rupture, based on a positive posterior drawer test, had a normal appearance of the PCL on an MRI scan. It is postulated that the PCL had been ruptured but healed in a lengthened state. 12 volunteers with no history of knee trauma underwent an MRI scan of the knee. In this control group (n = 12), there was a close correlation between the lateral femoral condylar width in the sagittal plane and the PCL length, with a ratio of 2:1 (95% confidence interval (CI) = 1.817-2.095). In the clinically abnormal group (n = 6), the ratio was 1.49:1 (95% CI = 1.206-1.782) (p< 0.0005). In conclusion, the ratio of the lateral femoral condylar width in the sagittal plane to the PCL length is a useful index for diagnosing PCL attenuation and lengthening in the presence of a normal morphological MR appearance.

  7. The effects of hippocampal lesions on MRI measures of structural and functional connectivity.

    Science.gov (United States)

    Henson, Richard N; Greve, Andrea; Cooper, Elisa; Gregori, Mariella; Simons, Jon S; Geerligs, Linda; Erzinçlioğlu, Sharon; Kapur, Narinder; Browne, Georgina

    2016-11-01

    Focal lesions can affect connectivity between distal brain regions (connectional diaschisis) and impact the graph-theoretic properties of major brain networks (connectomic diaschisis). Given its unique anatomy and diverse range of functions, the hippocampus has been claimed to be a critical "hub" in brain networks. We investigated the effects of hippocampal lesions on structural and functional connectivity in six patients with amnesia, using a range of magnetic resonance imaging (MRI) analyses. Neuropsychological assessment revealed marked episodic memory impairment and generally intact performance across other cognitive domains. The hippocampus was the only brain structure exhibiting reduced grey-matter volume that was consistent across patients, and the fornix was the only major white-matter tract to show altered structural connectivity according to both diffusion metrics. Nonetheless, functional MRI revealed both increases and decreases in functional connectivity. Analysis at the level of regions within the default-mode network revealed reduced functional connectivity, including between nonhippocampal regions (connectional diaschisis). Analysis at the level of functional networks revealed reduced connectivity between thalamic and precuneus networks, but increased connectivity between the default-mode network and frontal executive network. The overall functional connectome showed evidence of increased functional segregation in patients (connectomic diaschisis). Together, these results point to dynamic reorganization following hippocampal lesions, with both decreased and increased functional connectivity involving limbic-diencephalic structures and larger-scale networks. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.

  8. In vivo measurements of relaxation process in the human liver by MRI. The role of respiratory gating/triggering

    DEFF Research Database (Denmark)

    Thomsen, C; Henriksen, O; Ring, P

    1988-01-01

    In vivo estimation of relaxation processes in the liver by magnetic resonance imaging (MRI) may be helpful for characterization of various pathological conditions in the liver. However, such measurements may be significantly hampered by movement of the liver with the respiration. The effect...... of synchronization of data acquisition to the respiratory cycle on measured T1- and T2-relaxation curves was studied in normal subjects, patients with diffuse liver disease, and patients with focal liver pathology. Multi spin echo sequences with five different repetition times were used. The measurements were...... different, when respiratory synchronization was employed. The results indicate that respiratory synchronization is only necessary for estimation of relaxation processes in the liver with focal pathology....

  9. Global Functional Connectivity Differences between Sleep-Like States in Urethane Anesthetized Rats Measured by fMRI.

    Directory of Open Access Journals (Sweden)

    Ekaterina Zhurakovskaya

    Full Text Available Sleep is essential for nervous system functioning and sleep disorders are associated with several neurodegenerative diseases. However, the macroscale connectivity changes in brain networking during different sleep states are poorly understood. One of the hindering factors is the difficulty to combine functional connectivity investigation methods with spontaneously sleeping animals, which prevents the use of numerous preclinical animal models. Recent studies, however, have implicated that urethane anesthesia can uniquely induce different sleep-like brain states, resembling rapid eye movement (REM and non-REM (NREM sleep, in rodents. Therefore, the aim of this study was to assess changes in global connectivity and topology between sleep-like states in urethane anesthetized rats, using blood oxygenation level dependent (BOLD functional magnetic resonance imaging. We detected significant changes in corticocortical (increased in NREM-like state and corticothalamic connectivity (increased in REM-like state. Additionally, in graph analysis the modularity, the measure of functional integration in the brain, was higher in NREM-like state than in REM-like state, indicating a decrease in arousal level, as in normal sleep. The fMRI findings were supported by the supplementary electrophysiological measurements. Taken together, our results show that macroscale functional connectivity changes between sleep states can be detected robustly with resting-state fMRI in urethane anesthetized rats. Our findings pave the way for studies in animal models of neurodegenerative diseases where sleep abnormalities are often one of the first markers for the disorder development.

  10. MRI and low back pain

    Science.gov (United States)

    Backache - MRI; Low back pain - MRI; Lumbar pain - MRI; Back strain - MRI; Lumbar radiculopathy - MRI; Herniated intervertebral disk - MRI; Prolapsed intervertebral disk - MRI; Slipped disk - MRI; Ruptured ...

  11. Glottal jet measurements in synthetic, MRI-based human vocal fold models

    Science.gov (United States)

    Thomson, Scott; Pickup, Brian; Gollnick, Paul

    2007-11-01

    Human vocal fold vibration generates a time-varying elliptically-shaped glottal jet that produces sound in speech. Improved understanding of glottal jet dynamics can yield insight into voice production mechanisms and improve the diagnosis and treatment of voice disorders. Experiments using recently developed life-sized synthetic models of the vocal folds are presented. The fabrication process of converting MRI images to synthetic models is described. The process allows for varying the Young's modulus of the models, allowing for asymmetric conditions to be created by casting opposing vocal folds using materials of different stiffness. The models are shown to oscillate at frequencies, pressures, and flow rates typical of human speech. Phase-locked particle image velocimetry (PIV) results are presented which characterize the glottal jet, including jet direction, vortical structures, and turbulence levels. Results are shown for symmetric and asymmetric vocal fold models. The degree of material asymmetry required to cause significant asymmetry in the glottal jet is reported.

  12. Cerebrospinal fluid volumetric MRI mapping as a simple measurement for evaluating brain atrophy

    DEFF Research Database (Denmark)

    De Vis, J B; Zwanenburg, J J; van der Kleij, L A;

    2016-01-01

    ) and medial temporal lobe atrophy (MTA)] was evaluated. RESULTS: Relative total, peripheral subarachnoidal, and ventricular VCSF increased significantly with increased scores on the GCA and MTA (R = 0.83, 0.78 and 0.78 and R = 0.72, 0.62 and 0.86). Total, peripheral subarachnoidal, and ventricular T2...... of the CSF increased significantly with higher scores on the GCA and MTA (R = 0.72, 0.70 and 0.49 and R = 0.60, 0.57 and 0.41). CONCLUSION: A fast, fully automated CSF MRI volumetric sequence is an alternative for qualitative atrophy scales. The T2 of the CSF is related to brain atrophy and could thus...

  13. Evaluation of MRI-based Polymer Gel Dosimetry for Measurement of CT Dose Index (CTDI on 64 slices CT Scanners

    Directory of Open Access Journals (Sweden)

    Leaila Karimi-Afshar

    2009-06-01

    Full Text Available Introduction: Computed tomography (CT has numerous applications in clinical procedures but its main problem is its high radiation dose to the patients compared to other imaging modalities using x-ray. CT delivers approximately high doses to the nearby tissues due to the scattering effect, fan beam (beam divergence and limited collimator efficiency. The radiation dose from multi-slice scanners is greater than the single-slice scanners and since multi-slice scanners increasingly employ a wide beam, 100 mm ion chambers currently used in measuring the CTDI100, are not capable of accurately measuring the total dose profile of the slice width. Therefore, the CT dose is underestimated by using them. The purpose of this study is to measure the Computed Tomography Dose Index (CTDI of a GE multi-slice CT scanner (64-slice using polymer gel dosimetry based on MRI imaging (MRPD. CTDI is the sum of point doses along the central axis and estimates the average patient dose during CT scanning. Materials and Methods: For measuring CTDI, after designing and fabricating the phantom and preparing the MAGIC gel, MRI imaging using a 1.5 T Siemens MRI scanner was performed with the imaging parameters of ST = 2 mm, NEX = 1, TE = 20-640 ms and TR = 2000 ms. CTDI was measured with a 100 mm ion chamber (CTDI100 and also the MAGIC gel with MRPD method for 10 mm and 40 mm CT scan nominal widths. Results: Following the measurement of the CTDI100 for 10 mm and 40 mm nominal slice widths of the multi-slice scanner using both ion chamber and MAGIC gel, the results showed that the ion chamber underestimates CTDI100 by 28.71% and 14.03% compared to gel for 10 mm and 40 mm respectively. Discussion and Conclusion: It was concluded from this study that gel dosimeters have the capability to measure CTDI in wide beams of multi-slice CT scanners whereas 100 mm standard ion chamber due to its limited length is not reliable even for a 10 mm beam width. In addition, due to the 3

  14. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: an international multicenter reliability study using computerized MRI erosion volume measurements

    DEFF Research Database (Denmark)

    Bird, P; Ejbjerg, B; McQueen, F;

    2003-01-01

    with metacarpophalangeal (MCP) joints 2 to 5 of the dominant hand included in the field of view. Three readers were instructed to grade MCP 2 and 3 using the OMERACT grading system and then to measure the erosion volume of the same joints using OSIRIS software. The inter-reader reliability of the grading method....... Good correlation was demonstrated between the total erosion scores and the total erosion volumes. For both erosion volumes and erosion scores, 1 mm and 3 mm acquisitions produced variable results between readers, with no clear pattern of underestimation or overestimation for either slice thickness....... The volume estimation method was more time consuming, taking roughly 5 times as long as the scoring method. Computerized MRI erosion volume measurements are feasible, with high intra-observer and inter-occasion reliabilities. Despite high ICC, the inter-observer reliability is not sufficient for multicenter...

  15. 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...

  16. Hemodynamic Measurement Using Four-Dimensional Phase-Contrast MRI: Quantification of Hemodynamic Parameters and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Hojin [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Guk Bae [Asan Institute of Life Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kweon, Jihoon [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Young-Hak [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Deok Hee; Yang, Dong Hyun [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kim, Namkug [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of)

    2016-11-01

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  17. Hemodynamic measurement using four-dimensional phase-contrast MRI: Quantification of hemodynamic parameters and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ho Jin; Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Guk Bae; Kweon, Ji Hoon; Kim, Young Hak; Lee, Deok Hee; Yang, Dong Hyun; KIm, Nam Kug [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-07-15

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  18. ELISA-Based Measurement of Antibody Responses and PCR-Based Detection Profiles Can Distinguish between Active Infection and Early Clearance of Borrelia burgdorferi

    Directory of Open Access Journals (Sweden)

    John J. Lazarus

    2012-01-01

    Full Text Available Borrelia burgdorferi is a spirochetal bacterium that causes Lyme disease. These studies address whether current research methods using either ELISA to detect seroconversion to B. burgdorferi antigens or PCR quantification of bacterial DNA within tissues can accurately distinguish between a productive infection versus a B. burgdorferi exposure that is rapidly cleared by the innate responses. Mice receiving even minimal doses of live B. burgdorferi produced significantly more B. burgdorferi-specific IgM and IgG than groups receiving large inocula of heat-killed bacteria. Additionally, sera from mice injected with varied doses of killed B. burgdorferi recognized unique borrelial antigens compared to mice infected with live B. burgdorferi. Intradermal injection of killed B. burgdorferi resulted in rapid DNA clearance from skin, whereas DNA was consistently detected in skin inoculated with viable B. burgdorferi. These data indicate that both ELISA-based serological analyses and PCR-based methods of assessing B. burgdorferi infection clearly distinguish between an established infection with live bacteria and exposure to large numbers of bacteria that are promptly cleared by the innate responses.

  19. SU-D-303-03: Impact of Uncertainty in T1 Measurements On Quantification of Dynamic Contrast Enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Aryal, M; Cao, Y [The University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: Quantification of dynamic contrast enhanced (DCE) MRI requires native longitudinal relaxation time (T1) measurement. This study aimed to assess uncertainty in T1 measurements using two different methods. Methods and Materials: Brain MRI scans were performed on a 3T scanner in 9 patients who had low grade/benign tumors and partial brain radiotherapy without chemotherapy at pre-RT, week-3 during RT (wk-3), end-RT, and 1, 6 and 18 months after RT. T1-weighted images were acquired using gradient echo sequences with 1) 2 different flip angles (50 and 150), and 2) 5 variable TRs (100–2000ms). After creating quantitative T1 maps, average T1 was calculated in regions of interest (ROI), which were distant from tumors and received a total of accumulated radiation doses < 5 Gy at wk-3. ROIs included left and right normal Putamen and Thalamus (gray matter: GM), and frontal and parietal white matter (WM). Since there were no significant or even a trend of T1 changes from pre-RT to wk-3 in these ROIs, a relative repeatability coefficient (RC) of T1 as a measure of uncertainty was estimated in each ROI using the data pre-RT and at wk-3. The individual T1 changes at later time points were evaluated compared to the estimated RCs. Results: The 2-flip angle method produced small RCs in GM (9.7–11.7%) but large RCs in WM (12.2–13.6%) compared to the saturation-recovery (SR) method (11.0–17.7% for GM and 7.5–11.2% for WM). More than 81% of individual T1 changes were within T1 uncertainty ranges defined by RCs. Conclusion: Our study suggests that the impact of T1 uncertainty on physiological parameters derived from DCE MRI is not negligible. A short scan with 2 flip angles is able to achieve repeatability of T1 estimates similar to a long scan with 5 different TRs, and is desirable to be integrated in the DCE protocol. Present study was supported by National Institute of Health (NIH) under grant numbers; UO1 CA183848 and RO1 NS064973.

  20. Test-retest measurements of dopamine D{sub 1}-type receptors using simultaneous PET/MRI imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kaller, Simon; Patt, Marianne; Becker, Georg-Alexander; Luthardt, Julia; Meyer, Philipp M.; Werner, Peter; Barthel, Henryk; Bresch, Anke; Sabri, Osama [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Rullmann, Michael [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); Girbardt, Johanna [Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); Fritz, Thomas H. [Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); University of Gent, Institute for Psychoacoustics and Electronic Music (IPEM), Ghent (Belgium); Hesse, Swen [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Leipzig University Medical Centre, Integrated Research and Treatment Centre (IFB) Adiposity Diseases, Leipzig (Germany)

    2017-06-15

    The role of dopamine D{sub 1}-type receptor (D{sub 1}R)-expressing neurons in the regulation of motivated behavior and reward prediction has not yet been fully established. As a prerequisite for future research assessing D{sub 1}-mediated neuronal network regulation using simultaneous PET/MRI and D{sub 1}R-selective [{sup 11}C]SCH23390, this study investigated the stability of central D{sub 1}R measurements between two independent PET/MRI sessions under baseline conditions. Thirteen healthy volunteers (7 female, age 33 ± 13 yrs) underwent 90-min emission scans, each after 90-s bolus injection of 486 ± 16 MBq [{sup 11}C]SCH23390, on two separate days within 2-4 weeks using a PET/MRI system. Parametric images of D{sub 1}R distribution volume ratio (DVR) and binding potential (BP{sub ND}) were generated by a multi-linear reference tissue model with two parameters and the cerebellar cortex as receptor-free reference region. Volume-of-interest (VOI) analysis was performed with manual VOIs drawn on consecutive transverse MRI slices for brain regions with high and low D{sub 1}R density. The DVR varied from 2.5 ± 0.3 to 2.9 ± 0.5 in regions with high D{sub 1}R density (e.g. the head of the caudate) and from 1.2 ± 0.1 to 1.6 ± 0.2 in regions with low D{sub 1}R density (e.g. the prefrontal cortex). The absolute variability of the DVR ranged from 2.4% ± 1.3% to 5.1% ± 5.3%, while Bland-Altman analyses revealed very low differences in mean DVR (e.g. 0.013 ± 0.17 for the nucleus accumbens). Intraclass correlation (one-way, random) indicated very high agreement (0.93 in average) for both DVR and BP{sub ND} values. Accordingly, the absolute variability of BP{sub ND} ranged from 7.0% ± 4.7% to 12.5% ± 10.6%; however, there were regions with very low D{sub 1}R content, such as the occipital cortex, with higher mean variability. The test-retest reliability of D{sub 1}R measurements in this study was very high. This was the case not only for D{sub 1}R-rich brain areas, but

  1. Assessment of histological response of paediatric bone sarcomas using FDG PET in comparison to morphological volume measurement and standardized MRI parameters

    Energy Technology Data Exchange (ETDEWEB)

    Denecke, Timm; Misch, Daniel; Steffen, Ingo G.; Plotkin, Michail; Stoever, Brigitte [Charite - Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde, Campus Virchow-Klinikum, Berlin (Germany); Hundsdoerfer, Patrick; Henze, Guenter [Charite - Universitaetsmedizin Berlin, Klinik fuer Paediatrie m.S. Onkologie und Haematologie, Otto-Heubner-Zentrum, Campus Virchow-Klinikum, Berlin (Germany); Schoenberger, Stefan [Universitaetsklinikum der Heinrich-Heine-Universitaet Duesseldorf, Klinik fuer Kinder-Onkologie, -Haematologie und -Immunologie, Duesseldorf (Germany); Furth, Christian; Ruf, Juri [Otto-von-Guericke-Universitaet Magdeburg, Klinik fuer Radiologie und Nuklearmedizin, Universitaetsklinikum Magdeburg A.oe.R., Magdeburg (Germany); Hautzel, Hubertus [Universitaetsklinikum der Heinrich Heine Universitaet Duesseldorf, Nuklearmedizinische Klinik, Duesseldorf (Germany); Kluge, Regine [Universitaetsklinikum Leipzig A.oe.R., Klinik und Poliklinik fuer Nuklearmedizin, Leipzig (Germany); Bierbach, Uta [Universitaetsklinikum Leipzig A.oe.R., Abteilung fuer Kinder-Haematologie, -Onkologie und -Haemostaseologie, Leipzig (Germany); Otto, Sylke [Universitaetsklinikum Greifswald, Institut fuer Diagnostische Radiologie und Neuroradiologie, Greifswald (Germany); Beck, James F. [Universitaetsklinikum Greifswald, Abteilung fuer Paediatrische Haematologie und Onkologie, Greifswald (Germany); Franzius, Christiane [MR- und PET/CT-Zentrum, Bremen-Mitte (Germany); Universitaetsklinikum Muenster, Klinik und Poliklinik fuer Nuklearmedizin, Muenster (Germany); Amthauer, Holger [Charite - Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde, Campus Virchow-Klinikum, Berlin (Germany); Otto-von-Guericke-Universitaet Magdeburg, Klinik fuer Radiologie und Nuklearmedizin, Universitaetsklinikum Magdeburg A.oe.R., Magdeburg (Germany)

    2010-10-15

    The objective of this study was to evaluate positron emission tomography (PET) using {sup 18}F-fluoro-2-deoxy-D-glucose (FDG) in comparison to volumetry and standardized magnetic resonance imaging (MRI) parameters for the assessment of histological response in paediatric bone sarcoma patients. FDG PET and local MRI were performed in 27 paediatric sarcoma patients [Ewing sarcoma family of tumours (EWS), n = 16; osteosarcoma (OS), n = 11] prior to and after neoadjuvant chemotherapy before local tumour resection. Several parameters for assessment of response of the primary tumour to therapy by FDG PET and MRI were evaluated and compared with histopathological regression of the resected tumour as defined by Salzer-Kuntschik. FDG PET significantly discriminated responders from non-responders using the standardized uptake value (SUV) reduction and the absolute post-therapeutic SUV (SUV2) in the entire patient population ({nabla}SUV, p = 0.005; SUV2, p = 0.011) as well as in the subgroup of OS patients ({nabla}SUV, p = 0.009; SUV2, p = 0.028), but not in the EWS subgroup. The volume reduction measured by MRI/CT did not significantly discriminate responders from non-responders either in the entire population (p = 0.170) or in both subgroups (EWS, p = 0.950; OS, p = 1.000). The other MRI parameters alone or in combination were unreliable and did not improve the results. Comparing diagnostic parameters of FDG PET and local MRI, metabolic imaging showed high superiority in the subgroup of OS patients, while similar results were observed in the population of EWS. FDG PET appears to be a useful tool for non-invasive response assessment in the group of OS patients and is superior to MRI. In EWS patients, however, neither FDG PET nor volumetry or standardized MRI criteria enabled a reliable response assessment to be made after neoadjuvant treatment. (orig.)

  2. 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.)

  3. Comparison of global cerebral blood flow measured by phase‐contrast mapping MRI with 15O‐H2O positron emission tomography

    Science.gov (United States)

    Lindberg, Ulrich; Aachmann‐Andersen, Niels Jacob; Lisbjerg, Kristian; Christensen, Søren Just; Rasmussen, Peter; Olsen, Niels Vidiendal; Law, Ian; Larsson, Henrik Bo Wiberg; Henriksen, Otto Mølby

    2016-01-01

    Purpose To compare mean global cerebral blood flow (CBF) measured by phase‐contrast mapping magnetic resonance imaging (PCM MRI) and by 15O‐H2O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo against an accepted reference technique. Materials and Methods Same‐day measurements of CBF by 15O‐H2O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one‐tissue compartment model with measurement of the arterial input function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume‐segmented 3D T 1‐weighted anatomical MR‐scan. Results Mean CBF was 34.9 ± 3.4 mL/100 g/min measured by 15O‐H2O PET and 57.0 ± 6.8 mL/100 g/min measured by PCM MRI. The measurements were highly correlated (P = 0.0008, R2 = 0.44), although values obtained by PCM MRI were higher compared to 15O‐H2O PET (absolute and relative differences were 22.0 ± 5.2 mL/100 g/min and 63.4 ± 14.8%, respectively). Conclusion This study confirms the use of PCM MRI for quantification of global CBF, but also that PCM MRI systematically yields higher values relative to 15O‐H2O PET, probably related to methodological bias. Level of Evidence: 3 J. Magn. Reson. Imaging 2017;45:692–699. PMID:27619317

  4. Measurement and Visualization of Tight Rock Exposed to CO2 Using NMR Relaxometry and MRI

    Science.gov (United States)

    Wang, Haitao; Lun, Zengmin; Lv, Chengyuan; Lang, Dongjiang; Ji, Bingyu; Luo, Ming; Pan, Weiyi; Wang, Rui; Gong, Kai

    2017-03-01

    Understanding mechanisms of oil mobilization of tight matrix during CO2 injection is crucial for CO2 enhanced oil recovery (EOR) and sequestration engineering design. In this study exposure behavior between CO2 and tight rock of the Ordos Basin has been studied experimentally by using nuclear magnetic resonance transverse relaxation time (NMR T2) spectrum and magnetic resonance imaging (MRI) under the reservoir pressure and temperature. Quantitative analysis of recovery at the pore scale and visualization of oil mobilization are achieved. Effects of CO2 injection, exposure times and pressure on recovery performance have been investigated. The experimental results indicate that oil in all pores can be gradually mobilized to the surface of rock by CO2 injection. Oil mobilization in tight rock is time-consuming while oil on the surface of tight rock can be mobilized easily. CO2 injection can effectively mobilize oil in all pores of tight rock, especially big size pores. This understanding of process of matrix exposed to CO2 could support the CO2 EOR in tight reservoirs.

  5. Regional MRI Perfusion Measures Predict Motor/Executive Function in Patients with Clinically Isolated Syndrome

    Directory of Open Access Journals (Sweden)

    Efrosini Z. Papadaki

    2014-01-01

    Full Text Available Background. Patients with clinically isolated syndrome (CIS demonstrate brain hemodynamic changes and also suffer from difficulties in processing speed, memory, and executive functions. Objective. To explore whether brain hemodynamic disturbances in CIS patients correlate with executive functions. Methods. Thirty CIS patients and forty-three healthy subjects, matched for age, gender, education level, and FSIQ, were administered tests of visuomotor learning and set shifting ability. Cerebral blood volume (CBV, cerebral blood flow (CBF, and mean transit time (MTT values were estimated in normal-appearing white matter (NAWM and normal-appearing deep gray Matter (NADGM structures, using a perfusion MRI technique. Results. CIS patients showed significantly elevated reaction time (RT on both tasks, while their CBV and MTT values were globally increased, probably due to inflammatory vasodilation. Significantly, positive correlation coefficients were found between error rates on the inhibition condition of the visuomotor learning task and CBV values in occipital, periventricular NAWM and both thalami. On the set shifting condition of the respective task significant, positive associations were found between error rates and CBV values in the semioval center and periventricular NAWM bilaterally. Conclusion. Impaired executive function in CIS patients correlated positively with elevated regional CBV values thought to reflect inflammatory processes.

  6. Combining classification with fMRI-derived complex network measures for potential neurodiagnostics.

    Directory of Open Access Journals (Sweden)

    Tomer Fekete

    Full Text Available Complex network analysis (CNA, a subset of graph theory, is an emerging approach to the analysis of functional connectivity in the brain, allowing quantitative assessment of network properties such as functional segregation, integration, resilience, and centrality. Here, we show how a classification framework complements complex network analysis by providing an efficient and objective means of selecting the best network model characterizing given functional connectivity data. We describe a novel kernel-sum learning approach, block diagonal optimization (BDopt, which can be applied to CNA features to single out graph-theoretic characteristics and/or anatomical regions of interest underlying discrimination, while mitigating problems of multiple comparisons. As a proof of concept for the method's applicability to future neurodiagnostics, we apply BDopt classification to two resting state fMRI data sets: a trait (between-subjects classification of patients with schizophrenia vs. controls, and a state (within-subjects classification of wake vs. sleep, demonstrating powerful discriminant accuracy for the proposed framework.

  7. Is the type and extent of hippocampal sclerosis measurable on high-resolution MRI?

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    Urbach, H; Schwarzwald, R [Medical Center University of Freiburg, Dept. of Neuroradiology, Freiburg (Germany); Huppertz, H.J. [Swiss Epilepsy Center, Zurich (Switzerland); Becker, A.J. [Medical Center University of Bonn, Department of Neuropathology, Bonn (Germany); Wagner, J. [Medical Center University of Bonn, Department of Epileptology, Bonn (Germany); Bahri, M. Delsous; Tschampa, H.J. [Medical Center University of Bonn, Department of Radiology/Neuroradiology, Bonn (Germany)

    2014-09-15

    The purpose of this study is to relate hippocampal volume and FLAIR signal intensity to Wyler grading of hippocampal sclerosis (HS). Of 100 consecutive patients with temporal lobe epilepsy and HS as histopathological diagnosis, 32 had high-resolution 3 Tesla MRI and anatomically well-preserved hippocampi following amygdalo-hippocampectomy. Hippocampal volume on 3D T1-weighted gradient echo and signal intensity on coronal FLAIR sequences were determined using FreeSurfer and SPM tools and related to Wyler grading. Seizure outcome was determined after 1 year. Histopathology showed four Wyler II, 19 Wyler III, and 9 Wyler IV HS. Hippocampal volumes were 3.08 ml for Wyler II (Wyler II/contralateral side: p > 0.05), 2.19 ml for Wyler III (p < 0.01), 2.62 ml for Wyler IV (p = 0.01), and 3.08 ml for the contralateral side. Normalized FLAIR signals were 1,354 (p = 0.0004), 1,408 (p < 0.0001), 1,371 (p < 0.04), and 1,296, respectively. Wyler II hippocampi were visually normal. Two of four (50 %) Wyler II, 16/19 (84 %) Wyler III, and 6/9 (66 %) Wyler IV patients achieved Engel I outcome. Combined volumetry and quantitative FLAIR signal analysis clearly identifies Wyler III and IV HS. Quantitative FLAIR signal analysis may be helpful to identify Wyler II HS. (orig.)

  8. Chemical shift-based MRI to measure fat fractions in dystrophic skeletal muscle

    Science.gov (United States)

    Triplett, William T.; Baligand, Celine; Forbes, Sean C.; Willcocks, Rebecca J.; Lott, Donovan J.; DeVos, Soren; Pollaro, Jim; Rooney, William D.; Sweeney, H. Lee; Bönnemann, Carsten; Wang, Dah-Jyuu; Vandenborne, Krista; Walter, Glenn A.

    2014-01-01

    Purpose The relationship between FF determined based on multiple TE, unipolar GE images and 1H-MRS was evaluated using different models for fat-water decomposition, signal-to-noise ratios (SNR), and excitation flip angles. Methods A combination of single voxel proton spectroscopy (1H-MRS) and gradient echo (GE) imaging was used to determine muscle fat fractions (FF) in both normal and dystrophic muscles. In order to cover a large range of FF, the soleus and vastus lateralis muscles of 22 unaffected control (CON), 16 subjects with Collagen VI (COL6), and 71 subjects with Duchenne muscular dystrophy (DMD) were studied. 1H-MRS based FF were corrected for the increased muscle 1H2O T1 and T2 values observed in dystrophic muscles. Results Excellent agreement was found between co-registered FF derived from GE images fit to a multipeak model with noise bias correction and the relaxation corrected 1H-MRS FF (y= 0.93×+0.003; R2=0.96) across the full range of FF. Relaxation corrected 1H-MRS FF and imaging based FF were significantly elevated (pmuscles. Conclusion FF, T2, and T1 were all sensitive to muscle involvement in dystrophic muscle. MRI offered an additional advantage over single voxel spectroscopy in that the tissue heterogeneity in FF could be readily determined. PMID:24006208

  9. Quantification of the effect of water exchange in dynamic contrast MRI perfusion measurements in the brain and heart

    DEFF Research Database (Denmark)

    Larsson, H B; Rosenbaum, S; Fritz-Hansen, T

    2001-01-01

    Measurement of myocardial and brain perfusion when using exogenous contrast agents (CAs) such as gadolinium-DTPA (Gd-DTPA) and MRI is affected by the diffusion of water between compartments. This water exchange may have an impact on signal enhancement, or, equivalently, on the longitudinal......(i)) by using a realistic simulation. These results were verified by in vivo studies of the heart and brain in humans. The conclusion is that water exchange between the vascular and extravascular extracellular space has no effect on K(i) estimation in the myocardium when a normal dose of Gd-DTPA is used. Water...... exchange can have a significant effect on perfusion estimation (F) in the brain when using Gd-DTPA, where it acts as an intravascular contrast agent....

  10. Precise spatial co-registration in simultaneous fNIRS and fMRI measurements using markers coaxially fixable to the optodes

    Science.gov (United States)

    Yamada, Toru; Matsuda, Keiji; Iwano, Takayuki; Umeyama, Shinji

    2014-03-01

    Similar to blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI), functional nearinfrared spectroscopy (fNIRS) observes regional hemodynamic responses associated with neuronal activation. However, the conventional criteria for detecting true positive fNIRS and fMRI signals appear to be based on different understandings of cerebral hemodynamics. Considerable numbers of fNIRS studies have ascribed the increase in oxygenated hemoglobin to a typical sign of functional activation, whereas the corresponding BOLD signal in fMRI directly correlates with a decrease in deoxygenated hemoglobin. This inconsistency requires solution through the simultaneous measurements of fNIRS and fMRI. In practice, however, there remain several technical problems associated with conducting simultaneous measurements with high reproducibility. One issue is the precise spatial registration of NIRS optodes in MR images. We prepared marker containers of an annular shape that can be coaxially fixed to the optode. Liquid paraffin with α-tocopheryl acetate, which exhibits a bright contrast in T1-weighted MR images of human heads, was solidified in each container by adding higher fatty acid. A subject wearing the marker-fixed optodes at parietal area participated in preliminary fNIRS and fMRI experiments; the subject was instructed to execute single-sided hand finger tapping. The positions showed that deoxygenated hemoglobin decreases in fNIRS coincided with the BOLD-positive region in fMRI. The prepared marker is chemically stable and repetitively usable. We believe that this simple method contributes precision to the co-registration of fNIRS and fMRI.

  11. Gender and age effects in structural brain asymmetry as measured by MRI texture analysis.

    Science.gov (United States)

    Kovalev, Vassili A; Kruggel, Frithjof; von Cramon, D Yves

    2003-07-01

    Effects of gender and age on structural brain asymmetry were studied by 3D texture analysis in 380 adults. Asymmetry is detected by comparing the complex 3D gray-scale image patterns in the left and right cerebral hemispheres as revealed by anatomical T1-weighted MRI datasets. The Talairach and Tournoux parcellation system was applied to study the asymmetry on five levels: the whole cerebrum, nine coronal sections, 12 axial sections, boxes resulting from both coronal and axial subdivisions, and by a sliding spherical window of 9 mm diameter. The analysis revealed that the brain asymmetry increases in the anterior-posterior direction starting from the central region onward. Male brains were found to be more asymmetric than female. This gender-related effect is noticeable in all brain areas but is most significant in the superior temporal gyrus, Heschl's gyrus, the adjacent white matter regions in the temporal stem and the knee of the optic radiation, the thalamus, and the posterior cingulate. The brain asymmetry increases significantly with age in the inferior frontal gyrus, anterior insula, anterior cingulate, parahippocampal gyrus, retrosplenial cortex, coronal radiata, and knee region of the internal capsule. Asymmetry decreases with age in the optic radiation, precentral gyrus, and angular gyrus. The texture-based method reported here is based on extended multisort cooccurrence matrices that employ intensity, gradient, and anisotropy features in a uniform way. It is sensitive, simple to reproduce, robust, and unbiased in the sense that segmentation of brain compartments and spatial transformations are not necessary. Thus, it should be considered as another tool for digital morphometry in neuroscience.

  12. Cognitive deterioration and functional compensation in ALS measured with fMRI using an inhibitory task.

    Science.gov (United States)

    Witiuk, Kelsey; Fernandez-Ruiz, Juan; McKee, Ryan; Alahyane, Nadia; Coe, Brian C; Melanson, Michel; Munoz, Douglas P

    2014-10-22

    Amyotrophic lateral sclerosis (ALS) is characterized by degeneration of upper and lower motor neurons, resulting in progressive weakness and muscle atrophy. Recent studies suggest that nondemented ALS patients can show selective cognitive impairments, predominantly executive dysfunction, but little is known about the neural basis of these impairments. Oculomotor studies in ALS have described deficits in antisaccade execution, which requires the implementation of a task set that includes inhibition of automatic responses followed by generation of a voluntary action. It has been suggested that the dorsolateral prefrontal cortex (DLPFC) contributes in this process. Thus, we investigated whether deterioration of executive functions in ALS patients, such as the ability to implement flexible behavior during the antisaccade task, is related to DLPFC dysfunction. While undergoing an fMRI scan, 12 ALS patients and 12 age-matched controls performed an antisaccade task with concurrent eye tracking. We hypothesized that DLPFC deficits would appear during the antisaccade preparation stage, when the task set is being established. ALS patients made more antisaccade direction errors and showed significant reductions in DLPFC activation. In contrast, regions, such as supplementary eye fields and frontal eye fields, showed increased activation that was anticorrelated with the number of errors. The ALS group also showed reduced saccadic latencies that correlated with increased activation across the oculomotor saccade system. These findings suggest that ALS results in deficits in the inhibition of automatic responses that are related to impaired DLPFC activation. However, they also suggest that ALS patients undergo functional changes that partially compensate the neurological impairment. Copyright © 2014 the authors 0270-6474/14/3414260-12$15.00/0.

  13. Comparison of global cerebral blood flow measured by phase-contrast mapping MRI with (15) O-H2 O positron emission tomography

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob;

    2017-01-01

    PURPOSE: To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by (15) O-H2 O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated...... of the arterial input function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume-segmented 3D T1 -weighted anatomical MR-scan. RESULTS: Mean CBF was 34.9 ± 3.4 mL/100 g...... in vivo against an accepted reference technique. MATERIALS AND METHODS: Same-day measurements of CBF by (15) O-H2 O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one-tissue compartment model with measurement...

  14. Examination of anticipated chemical shift and shape distortion effect on materials commonly used in prosthetic socket fabrication when measured using MRI: a validation study.

    Science.gov (United States)

    Safari, Mohammad Reza; Rowe, Philip; Buis, Arjan

    2013-01-01

    The quality of lower-limb prosthetic socket fit is influenced by shape and volume consistency during the residual limb shape-capturing process (i.e., casting). Casting can be quantified with magnetic resonance imaging (MRI) technology. However, chemical shift artifact and image distortion may influence the accuracy of MRI when common socket/casting materials are used. We used a purpose-designed rig to examine seven different materials commonly used in socket fabrication during exposure to MRI. The rig incorporated glass marker tubes filled with water doped with 1 g/L copper sulfate (CS) and 9 plastic sample vials (film containers) to hold the specific material specimens. The specimens were scanned 9 times in different configurations. The absolute mean difference of the glass marker tube length was 1.39 mm (2.98%) (minimum = 0.13 mm [0.30%], maximum = 5.47 mm [14.03%], standard deviation = 0.89 mm). The absolute shift for all materials was <1.7 mm. This was less than the measurement tolerance of +/-2.18 mm based on voxel (three-dimensional pixel) dimensions. The results show that MRI is an accurate and repeatable method for dimensional measurement when using matter containing water. Additionally, silicone and plaster of paris plus 1 g/L CS do not show a significant shape distortion nor do they interfere with the MRI image of the residual limb.

  15. Examination of anticipated chemical shift and shape distortion effect on materials commonly used in prosthetic socket fabrication when measured using MRI: A validation study

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Safari, PhD

    2013-02-01

    Full Text Available The quality of lower-limb prosthetic socket fit is influenced by shape and volume consistency during the residual limb shape-capturing process (i.e., casting. Casting can be quantified with magnetic resonance imaging (MRI technology. However, chemical shift artifact and image distortion may influence the accuracy of MRI when common socket/casting materials are used. We used a purpose-designed rig to examine seven different materials commonly used in socket fabrication during exposure to MRI. The rig incorporated glass marker tubes filled with water doped with 1 g/L copper sulfate (CS and 9 plastic sample vials (film containers to hold the specific material specimens. The specimens were scanned 9 times in different configurations. The absolute mean difference of the glass marker tube length was 1.39 mm (2.98% (minimum = 0.13 mm [0.30%], maximum = 5.47 mm [14.03%], standard deviation = 0.89 mm. The absolute shift for all materials was <1.7 mm. This was less than the measurement tolerance of +/–2.18 mm based on voxel (three-dimensional pixel dimensions. The results show that MRI is an accurate and repeatable method for dimensional measurement when using matter containing water. Additionally, silicone and plaster of paris plus 1 g/L CS do not show a significant shape distortion nor do they interfere with the MRI image of the residual limb.

  16. Linking non-invasive parametric MRI with invasive physiological measurements (MR-PHYSIOL): towards a hybrid and integrated approach for investigation of acute kidney injury in rats.

    Science.gov (United States)

    Pohlmann, A; Cantow, K; Hentschel, J; Arakelyan, K; Ladwig, M; Flemming, B; Hoff, U; Persson, P B; Seeliger, E; Niendorf, T

    2013-04-01

    Acute kidney injury of various origins shares a common link in the pathophysiological chain of events: imbalance between renal medullary oxygen delivery and oxygen demand. For in vivo assessment of kidney haemodynamics and oxygenation in animals, quantitative but invasive physiological methods are established. A very limited number of studies attempted to link these invasive methods with parametric Magnetic Resonance Imaging (MRI) of the kidney. Moreover, the validity of parametric MRI (pMRI) as a surrogate marker for renal tissue perfusion and renal oxygenation has not been systematically examined yet. For this reason, we set out to combine invasive techniques and non-invasive MRI in an integrated hybrid setup (MR-PHYSIOL) with the ultimate goal to calibrate, monitor and interpret parametric MR and physiological parameters by means of standardized interventions. Here we present a first report on the current status of this multi-modality approach. For this purpose, we first highlight key characteristics of renal perfusion and oxygenation. Second, concepts for in vivo characterization of renal perfusion and oxygenation are surveyed together with the capabilities of MRI for probing blood oxygenation-dependent tissue stages. Practical concerns evoked by the use of strong magnetic fields in MRI and interferences between MRI and invasive physiological probes are discussed. Technical solutions that balance the needs of in vivo physiological measurements together with the constraints dictated by small bore MR scanners are presented. An early implementation of the integrated MR-PHYSIOL approach is demonstrated including brief interventions of hypoxia and hyperoxia. Acta Physiologica © 2013 Scandinavian Physiological Society.

  17. Correlation between dynamic contrast-enhanced MRI and histopathology in the measurement of tumor and breast volume and their ratio in breast cancer patients: a prospective study

    Institute of Scientific and Technical Information of China (English)

    LIU Qian; YE Jing-ming; XU Ling; DUAN Xue-ning; ZHAO Jian-xin; LIU Yin-hua

    2012-01-01

    Background Earlier studies have examined the association between the diameter of primary tumors measured by magnetic resonance imaging (MRI) and histopathology in breast cancer patients.However,the diameter does not completely describe the dimensions of the breast tumor or its volumetric proportion relative to the whole breast.The association between breast tumor volume/breast volume ratios measured by these two techniques has not been reported.Methods Seventy-three patients were recruited from female patients with primary breast tumors admitted to our center between January and December 2010.They were divided into two groups.Group A (n=46) underwent modified radical mastectomy (MRM),and Group B (n=27) underwent preoperative neoadjuvant chemotherapy before MRM.They were examined by dynamic-contrast enhanced MRI (DCE-MRI) to measure breast volumes (BVs),tumor volumes (TVs),and tumor volume/breast volume ratios (TV/BV).These measurements were compared with histopathology results after MRM,and the associations between MRI and pathology were analyzed by linear regression and Bland-Altman analysis.Results For Group A,the correlation coefficients for BVs,TVs,and TV/BV ratios measured by the two techniques were 0.938,0.921,and 0.897 (all P <0.001),respectively.For Group B,the correlation coefficients for BVs,TVs,and TV/BV ratios were 0.936,0.902,and 0.869 (all P<0.01),respectively.The results suggest statistically significant correlations between these parameters measured by the two techniques for both groups.Conclusion For these patients,BVs,TVs,and TV/BV ratios measured by DCE-MRI significantly correlated with those determined by histopathology.

  18. MRI Scans

    Science.gov (United States)

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  19. Shoulder MRI

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    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  20. Multi-modal, Multi-measure, and Multi-class Discrimination of ADHD with Hierarchical Feature Extraction and Extreme Learning Machine Using Structural and Functional Brain MRI.

    Science.gov (United States)

    Qureshi, Muhammad Naveed Iqbal; Oh, Jooyoung; Min, Beomjun; Jo, Hang Joon; Lee, Boreom

    2017-01-01

    Structural and functional MRI unveil many hidden properties of the human brain. We performed this multi-class classification study on selected subjects from the publically available attention deficit hyperactivity disorder ADHD-200 dataset of patients and healthy children. The dataset has three groups, namely, ADHD inattentive, ADHD combined, and typically developing. We calculated the global averaged functional connectivity maps across the whole cortex to extract anatomical atlas parcellation based features from the resting-state fMRI (rs-fMRI) data and cortical parcellation based features from the structural MRI (sMRI) data. In addition, the preprocessed image volumes from both of these modalities followed an ANOVA analysis separately using all the voxels. This study utilized the average measure from the most significant regions acquired from ANOVA as features for classification in addition to the multi-modal and multi-measure features of structural and functional MRI data. We extracted most discriminative features by hierarchical sparse feature elimination and selection algorithm. These features include cortical thickness, image intensity, volume, cortical thickness standard deviation, surface area, and ANOVA based features respectively. An extreme learning machine performed both the binary and multi-class classifications in comparison with support vector machines. This article reports prediction accuracy of both unimodal and multi-modal features from test data. We achieved 76.190% (p multi-class settings as well as 92.857% (p multi-modal group analysis approach with multi-measure features may improve the accuracy of the ADHD differential diagnosis.

  1. Quantitative renal perfusion measurements in a rat model of acute kidney injury at 3T: testing inter- and intramethodical significance of ASL and DCE-MRI.

    Directory of Open Access Journals (Sweden)

    Fabian Zimmer

    Full Text Available OBJECTIVES: To establish arterial spin labelling (ASL for quantitative renal perfusion measurements in a rat model at 3 Tesla and to test the diagnostic significance of ASL and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI in a model of acute kidney injury (AKI. MATERIAL AND METHODS: ASL and DCE-MRI were consecutively employed on six Lewis rats, five of which had a unilateral ischaemic AKI. All measurements in this study were performed on a 3 Tesla MR scanner using a FAIR True-FISP approach and a TWIST sequence for ASL and DCE-MRI, respectively. Perfusion maps were calculated for both methods and the cortical perfusion of healthy and diseased kidneys was inter- and intramethodically compared using a region-of-interest based analysis. RESULTS/SIGNIFICANCE: Both methods produce significantly different values for the healthy and the diseased kidneys (P<0.01. The mean difference was 147±47 ml/100 g/min and 141±46 ml/100 g/min for ASL and DCE-MRI, respectively. ASL measurements yielded a mean cortical perfusion of 416±124 ml/100 g/min for the healthy and 316±102 ml/100 g/min for the diseased kidneys. The DCE-MRI values were systematically higher and the mean cortical renal blood flow (RBF was found to be 542±85 ml/100 g/min (healthy and 407±119 ml/100 g/min (AKI. CONCLUSION: Both methods are equally able to detect abnormal perfusion in diseased (AKI kidneys. This shows that ASL is a capable alternative to DCE-MRI regarding the detection of abnormal renal blood flow. Regarding absolute perfusion values, nontrivial differences and variations remain when comparing the two methods.

  2. Tunnel widening after ACL reconstruction with aperture screw fixation or all-inside reconstruction with suspensory cortical button fixation: Volumetric measurements on CT and MRI scans.

    Science.gov (United States)

    Mayr, Raul; Smekal, Vinzenz; Koidl, Christian; Coppola, Christian; Fritz, Josef; Rudisch, Ansgar; Kranewitter, Christof; Attal, René

    2017-10-01

    Tunnel widening after anterior cruciate ligament reconstruction (ACLR) is influenced by the surgical and fixation techniques used. Computed tomography (CT) is the most accurate image modality for assessing tunnel widening, but magnetic resonance imaging (MRI) might also be reliable for tunnel volume measurements. In the present study tunnel widening after ACLR using biodegradable interference screw fixation was compared with all-inside ACLR using button fixation, with tunnel volume changes being measured on CT and MRI scans. Randomized controlled trial; Level of evidence, 2. Thirty-three patients were randomly assigned to hamstring ACLR using a biodegradable interference screw or all-inside cortical button fixation. CT and MRI scanning were done at the time of surgery and six months after. Tunnel volume changes were calculated and compared. On CT, femoral tunnel volumes changed from the postoperative state (100%) to 119.8% with screw fixation and 143.2% with button fixation (P=0.023). The changes in tibial tunnel volumes were not significant (113.9% vs. 117.7%). The changes in bone tunnel volume measured on MRI were comparable with those on CT only for tunnels with interference screws. Tibial tunnels with button fixation were significantly underestimated on MRI scanning (P=0.018). All-inside ACLR using cortical button fixation results in increased femoral tunnel widening in comparison with ACLR with biodegradable interference screw fixation. MRI represents a reliable imaging modality for future studies investigating tunnel widening with interference screw fixation. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Magnetic resonance imaging is comparable to computed tomography for determination of glenoid version but does not accurately distinguish between Walch B2 and C classifications.

    Science.gov (United States)

    Lowe, Jeremiah T; Testa, Edward J; Li, Xinning; Miller, Suzanne; DeAngelis, Joseph P; Jawa, Andrew

    2017-04-01

    Computed tomography (CT) scan is the standard for the preoperative assessment of glenoid version and morphology before total shoulder arthroplasty. However, the capacity of magnetic resonance imaging (MRI) to visualize bone morphology has improved with advancing technology. The purpose of this study was to compare the accuracy of MRI to CT for assessment of glenoid version and Walch classification. Three fellowship-trained shoulder surgeons assessed glenoid version and Walch classification of 30 patients with primary shoulder osteoarthritis who received both CT and MRI scans before total shoulder arthroplasty. Version measurements, Walch classification, and observer agreement were compared. Mean glenoid version was -15.5° and -18.6° by CT and MRI, respectively (P = .17). Interobserver reliability coefficients were good for both imaging modalities (CT, 0.73; MRI, 0.62). Intraobserver coefficients were good to excellent for CT (range, 0.76-0.87) and good for MRI (range, 0.75-0.79). For Walch classification, interobserver reliability for both modalities was merely fair, whereas intraobserver reliability was moderate to good. Although identification of type A1, A2, and B1 was nearly identical between CT and MRI, there was observer disagreement on type B2 (P = .001) and C glenoids (P = .03). Specifically, MRI underidentified type B2 and overidentified type C compared with CT. MRI is largely comparable to CT scan for evaluation of the glenoid, with similar measurements of version and identification of less extreme Walch glenoids. However, MRI is less accurate at distinguishing between type B2 and C glenoids. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  4. FUNCTIONAL-ANATOMY OF THE SOFT-TISSUES OF THE HAND AND WRIST - INVIVO EXCURSION MEASUREMENT OF THE FLEXOR POLLICIS LONGUS-TENDON USING MRI

    NARCIS (Netherlands)

    HAM, SJ; KONINGS, JG; WOLF, RFE; MOOYAART, EL

    1993-01-01

    Magnetic resonance imaging (MRI) of the flexor pollicis longus-tendon (FPL-tendon) with the thumb in different positions allows the in vivo assessment of its abduction-adduction/flexion excursion. Measurements can also be performed in different positions of the wrist. In our study, the mean

  5. FUNCTIONAL-ANATOMY OF THE SOFT-TISSUES OF THE HAND AND WRIST - INVIVO EXCURSION MEASUREMENT OF THE FLEXOR POLLICIS LONGUS-TENDON USING MRI

    NARCIS (Netherlands)

    HAM, SJ; KONINGS, JG; WOLF, RFE; MOOYAART, EL

    1993-01-01

    Magnetic resonance imaging (MRI) of the flexor pollicis longus-tendon (FPL-tendon) with the thumb in different positions allows the in vivo assessment of its abduction-adduction/flexion excursion. Measurements can also be performed in different positions of the wrist. In our study, the mean excursio

  6. Improved Cardiac MRI Volume Measurements in Patients with Tetralogy of Fallot by Independent End-Systolic and End-Diastolic Phase Selection

    NARCIS (Netherlands)

    Freling, Hendrik G.; Pieper, Petronella G.; Vermeulen, Karin M.; van Swieten, Jeroen M.; Sijens, Paul E.; van Veldhuisen, Dirk J.; Willems, Tineke P.

    2013-01-01

    Objectives: To investigate to what extent cardiac MRI derived measurements of right ventricular (RV) volumes using the left ventricular (LV) end-systolic and end-diastolic frame misrepresent RV end-systolic and end-diastolic volumes in patients with tetralogy of Fallot (ToF) and a right bundle

  7. The impact of reliable pre-bolus T1 measurements or a fixed T1 value in the assessment of glioma patients with Dynamic Contrast Enhancing MRI

    DEFF Research Database (Denmark)

    Tietze, Anna; Mouridsen, Kim; Mikkelsen, Irene Klærke

    2015-01-01

    Purpose: Accurate quantification of hemodynamic parameters using Dynamic Contrast Enhanced MRI (DCE) requires a measurement of tissue T1 prior to contrast injection (T1). We evaluate (i) T1 estimation using the variable flip angle (VFA) and the saturation recovery (SR) techniques and (ii) investi...

  8. The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics

    NARCIS (Netherlands)

    M. Cibiş (Merih); K. Jarvis (Kelly); M. Markl (Michael); M. Rose (Michael); C. Rigsby (Cynthia); A.J. Barker (Alex J.); J.J. Wentzel (Jolanda)

    2015-01-01

    textabstractViscous dissipation inside Fontan circulation, a parameter associated with the exercise intolerance of Fontan patients, can be derived from computational fluid dynamics (CFD) or 4D flow MRI velocities. However, the impact of spatial resolution and measurement noise on the estimation of

  9. Simultaneous measurement of kidney function by dynamic contrast enhanced MRI and FITC-sinistrin clearance in rats at 3 tesla: initial results.

    Directory of Open Access Journals (Sweden)

    Frank G Zöllner

    Full Text Available Glomerular filtration rate (GFR is an essential parameter of kidney function which can be measured by dynamic contrast enhanced magnetic resonance imaging (MRI-GFR and transcutaneous approaches based on fluorescent tracer molecules (optical-GFR. In an initial study comparing both techniques in separate measurements on the same animal, the correlation of the obtained GFR was poor. The goal of this study was to investigate if a simultaneous measurement was feasible and if thereby, the discrepancies in MRI-GFR and optical-GFR could be reduced. For the experiments healthy and unilateral nephrectomised (UNX Sprague Dawley (SD rats were used. The miniaturized fluorescent sensor was fixed on the depilated back of an anesthetized rat. A bolus of 5 mg/100 g b.w. of FITC-sinistrin was intravenously injected. For dynamic contrast enhanced perfusion imaging (DCE-MRI a 3D time-resolved angiography with stochastic trajectories (TWIST sequence was used. By means of a one compartment model the excretion half-life (t1/2 of FITC-sinistrin was calculated and converted into GFR. GFR from DCE-MRI was calculated by fitting pixel-wise a two compartment renal filtration model. Mean cortical GFR and GFR by FITC-sinistrin were compared by Bland-Altman plots and pair-wise t-test. Results show that a simultaneous GFR measurement using both techniques is feasible. Mean optical-GFR was 4.34 ± 2.22 ml/min (healthy SD rats and 2.34 ± 0.90 ml/min (UNX rats whereas MRI-GFR was 2.10 ± 0.64 ml/min (SD rats and 1.17 ± 0.38 ml/min (UNX rats. Differences between healthy and UNX rats were significant (p<0.05 and almost equal percentage difference (46.1% and 44.3% in mean GFR were assessed with both techniques. Overall mean optical-GFR values were approximately twice as high compared to MRI-GFR values. However, compared to a previous study, our results showed a higher agreement. In conclusion, the possibility to use the transcutaneous method in MRI may have a huge impact in

  10. Statistical approach of measurement of signal to noise ratio in according to change pulse sequence on brain MRI meningioma and cyst images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eul Kyu [Inje Paik University Hospital Jeo-dong, Seoul (Korea, Republic of); Choi, Kwan Woo [Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [The Baekseok Culture University, Cheonan (Korea, Republic of); Jang, Seo Goo [The Soonchunhyang University, Asan (Korea, Republic of); Kim, Ki Won [Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Son, Soon Yong [The Wonkwang Health Science University, Iksan (Korea, Republic of); Min, Jung Whan; Son, Jin Hyun [The Shingu University, Sungnam (Korea, Republic of)

    2016-09-15

    The purpose of this study was to needed basis of measure MRI CAD development for signal to noise ratio (SNR) by pulse sequence analysis from region of interest (ROI) in brain magnetic resonance imaging (MRI) contrast. We examined images of brain MRI contrast enhancement of 117 patients, from January 2005 to December 2015 in a University-affiliated hospital, Seoul, Korea. Diagnosed as one of two brain diseases such as meningioma and cysts SNR for each patient's image of brain MRI were calculated by using Image J. Differences of SNR among two brain diseases were tested by SPSS Statistics21 ANOVA test for there was statistical significance (p < 0.05). We have analysis socio-demographical variables, SNR according to sequence disease, 95% confidence according to SNR of sequence and difference in a mean of SNR. Meningioma results, with the quality of distributions in the order of T1CE, T2 and T1, FLAIR. Cysts results, with the quality of distributions in the order of T2 and T1, T1CE and FLAIR. SNR of MRI sequences of the brain would be useful to classify disease. Therefore, this study will contribute to evaluate brain diseases, and be a fundamental to enhancing the accuracy of CAD development.

  11. Regional Reproducibility of BOLD Calibration Parameter M, OEF and Resting-State CMRO2 Measurements with QUO2 MRI

    Science.gov (United States)

    Lajoie, Isabelle; Tancredi, Felipe B.; Hoge, Richard D.

    2016-01-01

    The current generation of calibrated MRI methods goes beyond simple localization of task-related responses to allow the mapping of resting-state cerebral metabolic rate of oxygen (CMRO2) in micromolar units and estimation of oxygen extraction fraction (OEF). Prior to the adoption of such techniques in neuroscience research applications, knowledge about the precision and accuracy of absolute estimates of CMRO2 and OEF is crucial and remains unexplored to this day. In this study, we addressed the question of methodological precision by assessing the regional inter-subject variance and intra-subject reproducibility of the BOLD calibration parameter M, OEF, O2 delivery and absolute CMRO2 estimates derived from a state-of-the-art calibrated BOLD technique, the QUantitative O2 (QUO2) approach. We acquired simultaneous measurements of CBF and R2* at rest and during periods of hypercapnia (HC) and hyperoxia (HO) on two separate scan sessions within 24 hours using a clinical 3 T MRI scanner. Maps of M, OEF, oxygen delivery and CMRO2, were estimated from the measured end-tidal O2, CBF0, CBFHC/HO and R2*HC/HO. Variability was assessed by computing the between-subject coefficients of variation (bwCV) and within-subject CV (wsCV) in seven ROIs. All tests GM-averaged values of CBF0, M, OEF, O2 delivery and CMRO2 were: 49.5 ± 6.4 mL/100 g/min, 4.69 ± 0.91%, 0.37 ± 0.06, 377 ± 51 μmol/100 g/min and 143 ± 34 μmol/100 g/min respectively. The variability of parameter estimates was found to be the lowest when averaged throughout all GM, with general trends toward higher CVs when averaged over smaller regions. Among the MRI measurements, the most reproducible across scans was R2*0 (wsCVGM = 0.33%) along with CBF0 (wsCVGM = 3.88%) and R2*HC (wsCVGM = 6.7%). CBFHC and R2*HO were found to have a higher intra-subject variability (wsCVGM = 22.4% and wsCVGM = 16% respectively), which is likely due to propagation of random measurement errors, especially for CBFHC due to the low

  12. Accuracy of MRI volume measurements of breast lesions: comparison between automated, semiautomated and manual assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, Marga B.; Fournell, Daphne; Nadar, Beenarose Thanka; Figiel, Jens H.; Keil, Boris; Heverhagen, Johannes T. [Philipps University, Department of Radiology, Marburg (Germany); Behrens, Sarah N.M. [MeVis GmbH, Bremen (Germany)

    2009-05-15

    The aim of this study was to investigate the efficacy of a dedicated software tool for automated and semiautomated volume measurement in contrast-enhanced (CE) magnetic resonance mammography (MRM). Ninety-six breast lesions with histopathological workup (27 benign, 69 malignant) were re-evaluated by different volume measurement techniques. Volumes of all lesions were extracted automatically (AVM) and semiautomatically (SAVM) from CE 3D MRM and compared with manual 3D contour segmentation (manual volume measurement, MVM, reference measurement technique) and volume estimates based on maximum diameter measurement (MDM). Compared with MVM as reference method MDM, AVM and SAVM underestimated lesion volumes by 63.8%, 30.9% and 21.5%, respectively, with significantly different accuracy for benign (102.4%, 18.4% and 11.4%) and malignant (54.9%, 33.0% and 23.1%) lesions (p<0.05). Inter- and intraobserver reproducibility was best for AVM (mean difference {+-}2SD, 1.0{+-}9.7% and 1.8{+-}12.1%) followed by SAVM (4.3{+-}25.7% and 4.3{+-}7.9%), MVM (2.3{+-}38.2% and 8.6{+-}31.8%) and MDM (33.9{+-}128.4% and 9.3{+-}55.9%). SAVM is more accurate for volume assessment of breast lesions than MDM and AVM. Volume measurement is less accurate for malignant than benign lesions. (orig.)

  13. Effects of changing from non-accelerated to accelerated MRI for follow-up in brain atrophy measurement.

    Science.gov (United States)

    Leung, Kelvin K; Malone, Ian M; Ourselin, Sebastien; Gunter, Jeffrey L; Bernstein, Matt A; Thompson, Paul M; Jack, Clifford R; Weiner, Michael W; Fox, Nick C

    2015-02-15

    Stable MR acquisition is essential for reliable measurement of brain atrophy in longitudinal studies. One attractive recent advance in MRI is to speed up acquisition using parallel imaging (e.g. reducing volumetric T1-weighted acquisition scan times from around 9 to 5 min). In some studies, a decision to change to an accelerated acquisition may have been deliberately taken, while in others repeat scans may occasionally be accidentally acquired with an accelerated acquisition. In ADNI, non-accelerated and accelerated scans were acquired in the same scanning session on each individual. We investigated the impact on brain atrophy as measured by k-means normalized boundary shift integral (KN-BSI) and deformation-based morphometry when changing from non-accelerated to accelerated MRI acquisitions over a 12-month interval using scans of 422 subjects from ADNI. KN-BSIs were calculated using both a non-accelerated baseline scan and non-accelerated 12-month scans (i.e. consistent acquisition), and a non-accelerated baseline scan and an accelerated 12-month scan (i.e. changed acquisition). Fluid-based non-rigid registration was also performed on those scans to estimate the brain atrophy rate. We found that the effect on KN-BSI and fluid-based non-rigid registration depended on the scanner manufacturer. For KN-BSI, in Philips and Siemens scanners, the change had very little impact on the measured atrophy rate (increase of 0.051% in Philips and -0.035% in Siemens from consistent acquisition to changed acquisition), whereas, in GE, the change caused a mean reduction of 0.65% in the brain atrophy rate. This is likely due to the difference in tissue contrast between gray matter and cerebrospinal fluid in the non-accelerated and accelerated scans in GE, which uses IR-FSPGR instead of MP-RAGE. For fluid-based non-rigid registration, the change caused a mean increase of 0.29% in the brain atrophy rate in the changed acquisition compared with consistent acquisition in Philips

  14. Perfusion MRI (dynamic susceptibility contrast imaging) with different measurement approaches for the evaluation of blood flow and blood volume in human gliomas

    DEFF Research Database (Denmark)

    Thomsen, H; Steffensen, E; Larsson, Elna-Marie

    2012-01-01

    technique arterial spin labelling (ASL) presently provides measurement only of cerebral blood flow (CBF), which has not been widely used in human brain tumor studies. Purpose: To assess if measurement of blood flow is comparable with measurement of blood volume in human biopsy-proven gliomas obtained by DSC......, and glioblastomas. Results: rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r ¼ 0.60) and to the cerebellum (r ¼ 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated......-MRI using two different regions for normalization and two different measurement approaches. Material and Methods: Retrospective study of 61 patients with different types of gliomas examined with DSC perfusion MRI. Regions of interest (ROIs) were placed in tumor portions with maximum perfusion on rCBF and r...

  15. Extraction of the cerebral cortical boundaries from MRI for measurement of cortical thickness

    Science.gov (United States)

    Eskildsen, Simon F.; Uldahl, Mark; Ostergaard, Lasse R.

    2005-04-01

    Several neurodegenerative diseases, such as Alzheimer's disease, cause atrophy of the cerebral cortex. Measurements of cerebral cortical thickness and volume are used in the quantification and localization of atrophy. It is possible to measure the thickness of the cerebral cortex manually from magnetic resonance imaging, but partial volume effects, orthogonality problems, large amounts of manual labor and operator bias makes it difficult to conduct measurements on large patient populations. Automatic quantification and localization of atrophy is a highly desirable goal, as it facilitates the study of early anatomical changes and track disease progression on large populations. The first step in achieving this goal is to develop robust and accurate methods for measuring cortical thickness and volume automatically. We have developed a new method, capable of both extracting surface representations of the cortical boundaries from magnetic resonance imaging and measuring the cortical thickness. Experiments show that the developed method is robust and performs well on datasets of both healthy subjects and subjects suffering from Alzheimer's disease.

  16. Quantitative MRI measures of orbitofrontal cortex in patients with chronic schizophrenia or schizoaffective disorder.

    Science.gov (United States)

    Hoptman, Matthew J; Volavka, Jan; Weiss, Elisabeth M; Czobor, Pál; Szeszko, Philip R; Gerig, Guido; Chakos, Miranda; Blocher, Joseph; Citrome, Leslie L; Lindenmayer, Jean-Pierre; Sheitman, Brian; Lieberman, Jeffrey A; Bilder, Robert M

    2005-11-30

    The relationship between orbitofrontal cortex (OFC) volumes and functional domains in treatment-resistant patients with schizophrenia or schizoaffective disorder is poorly understood. OFC dysfunction is implicated in several of the behaviors that are abnormal in schizophrenia. However, little is known about the relationship between these behaviors and OFC volumes. Forty-nine patients received magnetic resonance imaging scanning as part of a double-blind treatment study in which psychiatric symptomatology, neuropsychological function, and aggression were measured. OFC volumes were manually traced on anatomical images. Psychiatric symptomatology was measured with the Positive and Negative Syndrome Scale (PANSS). Aggression was measured with the Overt Aggression Scale (OAS) and with the PANSS. Neuropsychological function was assessed using a comprehensive test battery. Larger right OFC volumes were associated with poorer neuropsychological function. Larger left OFC gray matter volumes and larger OFC white matter volumes bilaterally were associated with greater levels of aggression. These findings are discussed in the context of potential iatrogenic effects.

  17. Citicoline Treatment Improves Measures of Impulsivity and Task Performance in Chronic Marijuana Smokers: A Pilot BOLD fMRI Study.

    Science.gov (United States)

    Gruber, Staci A; Sagar, Kelly A; Dahlgren, Mary Kathryn; Gonenç, Atilla; Conn, Nina A; Winer, Jeffrey P; Penetar, David; Lukas, Scott E

    2015-09-30

    Citicoline is an endogenous nucleotide that has historically been used to treat stroke, traumatic brain injury, and cognitive dysfunction. Research has also shown that citicoline treatment is associated with improved cognitive performance in substance-abusing populations. We hypothesized that marijuana (MJ) smokers who received citicoline would demonstrate improvement in cognitive performance as well as increased neural efficiency during tasks of cognitive control relative to those who received placebo. The current study tested this hypothesis by examining the effects of citicoline in treatment-seeking chronic MJ smokers. In an 8-week double-blind, placebo-controlled study, 19 MJ smokers were randomly assigned via a double-blind procedure to the citicoline (8 Males, 2 Females) or placebo group (9 Males, 0 Females). All participants completed fMRI scanning at baseline and after 8 weeks of treatment during two cognitive measures of inhibitory processing, the Multi Source Interference Test (MSIT) and Stroop Color Word Test, and also completed the Barratt Impulsiveness Scale (BIS-11), a self-report measure of impulsivity. Following the 8 week trial, MJ smokers treated with citicoline demonstrated significantly lower levels of behavioral impulsivity, improved task accuracy on both the MSIT and Stroop tasks, and exhibited significantly different patterns of brain activation relative to baseline levels and relative to those who received placebo. Findings suggest that citicoline may facilitate the treatment of MJ use disorders by improving the cognitive skills necessary to fully engage in comprehensive treatment programs.

  18. Assessment of Renal Hemodynamics and Oxygenation by Simultaneous Magnetic Resonance Imaging (MRI) and Quantitative Invasive Physiological Measurements.

    Science.gov (United States)

    Cantow, Kathleen; Arakelyan, Karen; Seeliger, Erdmann; Niendorf, Thoralf; Pohlmann, Andreas

    2016-01-01

    In vivo assessment of renal perfusion and oxygenation under (patho)physiological conditions by means of noninvasive diagnostic imaging is conceptually appealing. Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and quantitative parametric mapping of the magnetic resonance (MR) relaxation times T 2* and T 2 are thought to provide surrogates of renal tissue oxygenation. The validity and efficacy of this technique for quantitative characterization of local tissue oxygenation and its changes under different functional conditions have not been systematically examined yet and remain to be established. For this purpose, the development of an integrative multimodality approaches is essential. Here we describe an integrated hybrid approach (MR-PHYSIOL) that combines established quantitative physiological measurements with T 2* (T 2) mapping and MR-based kidney size measurements. Standardized reversible (patho)physiologically relevant interventions, such as brief periods of aortic occlusion, hypoxia, and hyperoxia, are used for detailing the relation between the MR-PHYSIOL parameters, in particular between renal T 2* and tissue oxygenation.

  19. Quality assurance in functional MRI

    DEFF Research Database (Denmark)

    Liu, Thomas T; Glover, Gary H; Mueller, Bryon A

    2015-01-01

    Over the past 20 years, functional magnetic resonance imaging (fMRI) has ben- efited greatly from improvements in MRI hardware and software. At the same time, fMRI researchers have pushed the technical limits of MRI systems and greatly in- fluenced the development of state-of-the-art systems....... Minimizing image noise and maximizing system stability is critical in fMRI because the blood oxygenation level- dependent (BOLD) signal changes that are used for most fMRI studies represent only a small fraction of the total MR signal. In addition, multiple imaging volumes must be acquired over time to track...... cognitive processes. As a result, MRI scanners must have excellent time-series stability to accurately measure BOLD signal changes over the course of a long time series (typically on the order of 10 min per scan). fMRI studies are particularly demanding on the scanner hardware because they utilize fast...

  20. Respiration gating and Bloch fitting improve pH measurements with acidoCEST MRI in an ovarian orthotopic tumor model

    Science.gov (United States)

    Jones, Kyle M.; Randtke, Edward A.; Howison, Christine M.; Pagel, Mark D.

    2016-03-01

    We have developed a MRI method that can measure extracellular pH in tumor tissues, known as acidoCEST MRI. This method relies on the detection of Chemical Exchange Saturation Transfer (CEST) of iopamidol, an FDA-approved CT contrast agent that has two CEST signals. A log10 ratio of the two CEST signals is linearly correlated with pH, but independent of agent concentration, endogenous T1 relaxation time, and B1 inhomogeneity. Therefore, detecting both CEST effects of iopamidol during in vivo studies can be used to accurately measure the extracellular pH in tumor tissues. Past in vivo studies using acidoCEST MRI have suffered from respiration artifacts in orthotopic and lung tumor models that have corrupted pH measurements. In addition, the non-linear fitting method used to analyze results is unreliable as it is subject to over-fitting especially with noisy CEST spectra. To improve the technique, we have recently developed a respiration gated CEST MRI pulse sequence that has greatly reduced motion artifacts, and we have included both a prescan and post scan to remove endogenous CEST effects. In addition, we fit the results by parameterizing the contrast of the exogenous agent with respect to pH via the Bloch equations modified for chemical exchange, which is less subject to over-fitting than the non-linear method. These advances in the acidoCEST MRI technique and analysis methods have made pH measurements more reliable, especially in areas of the body subject to respiratory motion.

  1. Measurement with microscopic MRI and simulation of flow in different aneurysm models

    Energy Technology Data Exchange (ETDEWEB)

    Edelhoff, Daniel, E-mail: daniel.edelhoff@tu-dortmund.de; Frank, Frauke; Heil, Marvin; Suter, Dieter [Experimental Physics III, TU Dortmund University, Otto-Hahn-Street 4, Dortmund 44227 (Germany); Walczak, Lars; Weichert, Frank [Computer Science VII, TU Dortmund University, Otto-Hahn-Street 16, Dortmund 44227 (Germany); Schmitz, Inge [Institute for Pathology, Ruhr Universität Bochum, Bürkle-de-la-Camp-Platz 1, Bochum 44789 (Germany)

    2015-10-15

    Purpose: The impact and the development of aneurysms depend to a significant degree on the exchange of liquid between the regular vessel and the pathological extension. A better understanding of this process will lead to improved prediction capabilities. The aim of the current study was to investigate fluid-exchange in aneurysm models of different complexities by combining microscopic magnetic resonance measurements with numerical simulations. In order to evaluate the accuracy and applicability of these methods, the fluid-exchange process between the unaltered vessel lumen and the aneurysm phantoms was analyzed quantitatively using high spatial resolution. Methods: Magnetic resonance flow imaging was used to visualize fluid-exchange in two different models produced with a 3D printer. One model of an aneurysm was based on histological findings. The flow distribution in the different models was measured on a microscopic scale using time of flight magnetic resonance imaging. The whole experiment was simulated using fast graphics processing unit-based numerical simulations. The obtained simulation results were compared qualitatively and quantitatively with the magnetic resonance imaging measurements, taking into account flow and spin–lattice relaxation. Results: The results of both presented methods compared well for the used aneurysm models and the chosen flow distributions. The results from the fluid-exchange analysis showed comparable characteristics concerning measurement and simulation. Similar symmetry behavior was observed. Based on these results, the amount of fluid-exchange was calculated. Depending on the geometry of the models, 7% to 45% of the liquid was exchanged per second. Conclusions: The result of the numerical simulations coincides well with the experimentally determined velocity field. The rate of fluid-exchange between vessel and aneurysm was well-predicted. Hence, the results obtained by simulation could be validated by the experiment. The

  2. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... distinguish between cancer tissue and fluid, known as edema . MRI typically costs more and may take more time to perform than other imaging modalities. top of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  3. Cerebral blood oxygenation changes during neuronal activation in stroke patients measured by near infrared spectroscopy and BOLD-functional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Yoshihiro; Fukaya, Chikashi; Sakatani, Kaoru; Katayama, Yoichi [Nihon Univ., Tokyo (Japan). School of Medicine

    2002-03-01

    Blood Oxygenation Level Dependent (BOLD)-fMRI images areas of activation by detecting a reduced concentration of deoxyhemoglobin during neuronal activity, which is caused by a larger increase in O{sub 2} delivery as compared to O{sub 2} consumption in normal adults. In the present study, near infrared spectroscopy demonstrated an increase of deoxyhemoglobin associated with increases of oxyhemoglobin and total hemoglobin in activation areas of stroke patients, whereas BOLD-fMRI failed to image such activation areas. The findings obtained have serious implications for the application of BOLD-fMRI to patients with brain disorders, since BOLD-fMRI may overlook neuronal activities in these patients. (author)

  4. MRI blood-brain barrier permeability measurements to predict hemorrhagic transformation in a rat model of ischemic stroke.

    Science.gov (United States)

    Hoffmann, Angelika; Bredno, Jörg; Wendland, Michael F; Derugin, Nikita; Hom, Jason; Schuster, Tibor; Zimmer, Claus; Su, Hua; Ohara, Peter T; Young, William L; Wintermark, Max

    2012-12-01

    Permeability imaging might add valuable information in the risk assessment of hemorrhagic transformation. This study evaluates the predictive value of blood-brain barrier permeability (BBBP) measurements extracted from dynamic contrast-enhanced MRI for hemorrhagic transformation in ischemic stroke. Spontaneously hypertensive and Wistar rats with 2 h filament occlusion of the right MCA underwent MRI during occlusion, at 4 and 24 h post reperfusion. BBBP was imaged by DCE imaging and quantified by Patlak analysis. Cresyl-violet staining was used to characterize hemorrhage in sacrificed rats at 24 h, immediately following the last imaging study. BBBP changes were evaluated at baseline, 4 and 24 h after reperfusion. Receiver-operating characteristic (ROC) analysis was performed to determine the most accurate BBBP threshold to predict hemorrhagic transformation. In animals showing macroscopic hemorrhage at 24 h, 95th BBBP percentile values ipsilateral were 0.323 [0.260, 0.387], 0.685 [0.385, 0.985], and 0.412 [0.210, 0.613] ml/min·100 g (marginal mean [95%CI]) during occlusion, at 4 and 24 h post reperfusion, respectively. The BBBP values on the infarcted and contralateral side were significantly different at 4 (p = 0.034) and 24 h post reperfusion (p = 0.031). The predictive value of BBBP in terms of macroscopic hemorrhage was highest 4 h after reperfusion (ROC area under the curve = 84 %) with a high negative predictive value (98.3 %) and limited positive predictive value (14.9 %) for a threshold of 0.35 ml/min·100g. Altered BBBP is a necessary but not sufficient condition to cause hemorrhagic transformation in rats with an infarct. Further research is needed to identify those additional risk factors that are required for hemorrhagic transformation to develop in the setting of ischemic stroke.

  5. Hemodynamic significance of coronary stenosis by vessel attenuation measurement on CT compared with adenosine perfusion MRI

    Energy Technology Data Exchange (ETDEWEB)

    Dekker, Martijn A.M. den; Pelgrim, Gert Jan; Pundziute, Gabija; Heuvel, Edwin R. van den; Oudkerk, Matthijs; Vliegenthart, Rozemarijn, E-mail: r.vliegenthart@umcg.nl

    2015-01-15

    Highlights: • The majority of anatomical coronary stenoses do not cause myocardial ischemia. • cCTA-derived CCO decrease expresses luminal density gradient across stenosis. • CCO decrease differentiates between anatomical stenoses with and without associated myocardial ischemia. • CCO decrease assessment can exclude the majority of stenoses without hemodynamic significance. - Abstract: Purpose: We assessed the association between corrected contrast opacification (CCO) based on coronary computed tomography angiography (cCTA) and inducible ischemia by adenosine perfusion magnetic resonance imaging (APMR). Methods: Sixty cardiac asymptomatic patients with extra-cardiac arterial disease (mean age 64.4 ± 7.7 years; 78% male) underwent cCTA and APMR. Luminal CT attenuation values (Hounsfield Units) were measured in coronary arteries from proximal to distal, with additional measurements across sites with >50% lumen stenosis. CCO was calculated by dividing coronary CT attenuation by descending aorta CT attenuation. A reversible perfusion defect on APMR was considered as myocardial ischemia. Results: In total, 169 coronary stenoses were found. Seven patients had 8 perfusion defects on APMR, with 11 stenoses in corresponding vessels. CCO decrease across stenoses with hemodynamic significance was 0.144 ± 0.112 compared to 0.047 ± 0.104 across stenoses without hemodynamic significance (P = 0.003). CCO decrease in lesions with and without anatomical stenosis was similar (0.054 ± 0.116 versus 0.052 ± 0.101; P = 0.89). Using 0.20 as preliminary CCO decrease cut-off, hemodynamic significance would be excluded in 82.9% of anatomical stenoses. Conclusions: CCO decrease across coronary stenosis is associated with myocardial ischemia on APMR. CCO based on common cCTA data is a novel method to assess hemodynamic significance of anatomical stenosis.

  6. CBF/CMRO2 coupling measured with calibrated BOLD fMRI: sources of bias.

    Science.gov (United States)

    Leontiev, Oleg; Dubowitz, David J; Buxton, Richard B

    2007-07-15

    The coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during brain activation can be characterized by an empirical index n, the ratio of fractional CBF changes to fractional CMRO2 changes. Measurements of n have yielded varying results, and it is not known if the observed variability is due to measurement techniques or underlying physiology. The calibrated BOLD approach using hypercapnia offers a promising tool for assessing changes in CBF/CMRO2 coupling in health and disease, but potential systematic errors have not yet been characterized. The goal of this study was to experimentally evaluate the magnitude of bias in the estimate of n that arises from the way in which a region of interest (ROI) is chosen for averaging data and to relate this potential bias to a more general theoretical consideration of the sources of systematic errors in the calibrated BOLD experiment. Results were compared for different approaches for defining an ROI within the visual cortex based on: (1) retinotopically defined V1; (2) a functional CBF localizer; and (3) a functional BOLD localizer. Data in V1 yielded a significantly lower estimate of n (2.45) compared to either CBF (n=3.45) or BOLD (n=3.18) localizers. Different statistical thresholds produced biases in estimates of n with values ranging from 3.01 (low threshold) to 4.37 (high threshold). Possible sources of the observed biases are discussed. These results underscore the importance of a critical evaluation of the methodology, and the adoption of consistent standards for applying the calibrated BOLD approach to the evaluation of CBF/CMRO2 coupling.

  7. CBF/CMRO2 Coupling Measured with Calibrated-BOLD fMRI: Sources of Bias

    Science.gov (United States)

    Leontiev, Oleg; Dubowitz, David J.; Buxton, Richard B.

    2007-01-01

    The coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during brain activation can be characterized by an empirical index n, the ratio of fractional CBF changes to fractional CMRO2 changes. Measurements of n have yielded varying results, and it is not known if the observed variability is due to measurement techniques or underlying physiology. The calibrated BOLD approach using hypercapnia offers a promising tool for assessing changes in CBF/CMRO2 coupling in health and disease, but potential systematic errors have not yet been characterized. The goal of this study was to experimentally evaluate the magnitude of bias in the estimate of n that arises from the way in which a region of interest (ROI) is chosen for averaging data, and to relate this potential bias to a more general theoretical consideration of the sources of systematic errors in the calibrated BOLD experiment. Results were compared for different approaches for defining an ROI within the visual cortex based on: 1) retinotopically-defined V1; 2) a functional CBF localizer; and 3) a functional BOLD localizer. Data in V1 yielded a significantly lower estimate of n (2.45) compared to either CBF (n = 3.45) or BOLD (n = 3.18) localizers. Different statistical thresholds produced biases in estimates of n with values ranging from 3.01 (low threshold) to 4.37 (high threshold). Possible sources of the observed biases are discussed. These results underscore the importance of a critical evaluation of the methodology, and the adoption of consistent standards for applying the calibrated BOLD approach to the evaluation of CBF/CMRO2 coupling. PMID:17524665

  8. Application of fMRI to obesity research: differences in reward pathway activation measured with fMRI BOLD during visual presentation of high and low calorie foods

    Science.gov (United States)

    Tsao, Sinchai; Adam, Tanja C.; Goran, Michael I.; Singh, Manbir

    2012-03-01

    The factors behind the neural mechanisms that motivate food choice and obesity are not well known. Furthermore, it is not known when these neural mechanisms develop and how they are influenced by both genetic and environmental factors. This study uses fMRI together with clinical data to shed light on the aforementioned questions by investigating how appetite-related activation in the brain changes with low versus high caloric foods in pre-pubescent girls. Previous studies have shown that obese adults have less striatal D2 receptors and thus reduced Dopamine (DA) signaling leading to the reward-deficit theory of obesity. However, overeating in itself reduces D2 receptor density, D2 sensitivity and thus reward sensitivity. The results of this study will show how early these neural mechanisms develop and what effect the drastic endocrinological changes during puberty has on these mechanisms. Our preliminary results showed increased activations in the Putamen, Insula, Thalamus and Hippocampus when looking at activations where High Calorie > Low Calorie. When comparing High Calorie > Control and Low Calorie > Control, the High > Control test showed increased significant activation in the frontal lobe. The Low > Control also yielded significant activation in the Left and Right Fusiform Gyrus, which did not appear in the High > Control test. These results indicate that the reward pathway activations previously shown in post-puberty and adults are present in pre-pubescent teens. These results may suggest that some of the preferential neural mechanisms of reward are already present pre-puberty.

  9. Improved measurement of brain deformation during mild head acceleration using a novel tagged MRI sequence.

    Science.gov (United States)

    Knutsen, Andrew K; Magrath, Elizabeth; McEntee, Julie E; Xing, Fangxu; Prince, Jerry L; Bayly, Philip V; Butman, John A; Pham, Dzung L

    2014-11-07

    In vivo measurements of human brain deformation during mild acceleration are needed to help validate computational models of traumatic brain injury and to understand the factors that govern the mechanical response of the brain. Tagged magnetic resonance imaging is a powerful, noninvasive technique to track tissue motion in vivo which has been used to quantify brain deformation in live human subjects. However, these prior studies required from 72 to 144 head rotations to generate deformation data for a single image slice, precluding its use to investigate the entire brain in a single subject. Here, a novel method is introduced that significantly reduces temporal variability in the acquisition and improves the accuracy of displacement estimates. Optimization of the acquisition parameters in a gelatin phantom and three human subjects leads to a reduction in the number of rotations from 72 to 144 to as few as 8 for a single image slice. The ability to estimate accurate, well-resolved, fields of displacement and strain in far fewer repetitions will enable comprehensive studies of acceleration-induced deformation throughout the human brain in vivo. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Measurement of coronary flow response to cold pressor stress in asymptomatic women with cardiovascular risk factors using spiral velocity-encoded cine MRI at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Maroules, Christopher D.; Peshock, Ronald M. (Dept. of Radiology, Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)), e-mail: Ron.Peshock@UTSouthwestern.edu; Chang, Alice Y.; Kontak, Andrew (Dept. of Internal Medicine, Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)); Dimitrov, Ivan; Kotys, Melanie (Dept. of Philips Medical Systems, Cleveland, OH (United States))

    2010-05-15

    Background: Coronary sinus (CS) flow in response to a provocative stress has been used as a surrogate measure of coronary flow reserve, and velocity-encoded cine (VEC) magnetic resonance imaging (MRI) is an established technique for measuring CS flow. In this study, the cold pressor test (CPT) was used to measure CS flow response because it elicits an endothelium-dependent coronary vasodilation that may afford greater sensitivity for detecting early changes in coronary endothelial function. Purpose: To investigate the feasibility and reproducibility of CS flow reactivity (CSFR) to CPT using spiral VEC MRI at 3 Tesla in a sample of asymptomatic women with cardiovascular risk factors. Material and Methods: Fourteen asymptomatic women (age 38 years +- 10) with cardiovascular risk factors were studied using 3D spiral VEC MRI of the CS at 3 T. The CPT was utilized as a provocative stress to measure changes in CS flow. CSFR to CPT was calculated from the ratio of CS flow during peak stress to baseline CS flow. Results: CPT induced a significant hemodynamic response as measured by a 45% increase in rate-pressure product (P<0.01). A significant increase in CS volume flow was also observed (baseline, 116 +- 26 ml/min; peak stress, 152 +- 34 ml/min, P=0.01). CSFR to CPT was 1.31 +- 0.20. Test-retest variability of CS volume flow was 5% at baseline and 6% during peak stress. Conclusion: Spiral CS VEC MRI at 3 T is a feasible and reproducible technique for measuring CS flow in asymptomatic women at risk for cardiovascular disease. Significant changes in CSFR to CPT are detectable, without demanding pharmacologic stress

  11. Using perfusion MRI to measure the dynamic changes in neural activation associated with tonic muscular pain.

    Science.gov (United States)

    Owen, Daron G; Clarke, Collin F; Ganapathy, Sugantha; Prato, Frank S; St Lawrence, Keith S

    2010-03-01

    Knowledge regarding neural pain processing is primarily the result of studies involving models of brief cutaneous pain; however, clinical pain generally originates in deep tissue and is prolonged. This study measured the dynamic neural activation associated with a muscular pain model incorporating both acute and tonic states. Hypertonic saline (5% NaCl) was infused into the brachioradialis muscle of eleven healthy volunteers for 15min after an initial bolus of 0.5mL. Ten controls followed the same protocol with normal saline (0.9% NaCl). Magnetic resonance images of cerebral blood flow (CBF) were acquired using an arterial spin labelling method. The imaging volume extended from the thalamus to the primary somatosensory cortices, but did not include the brainstem and cerebellum. Using a numerical scale from 0 to 10, ratings of pain intensity peaked at 5.9+/-0.6 and remained near 5 for the remainder of the trial. Controls experienced minimal pain, reporting a peak value of 1.8+/-0.4. Significant CBF increases in rostral and caudal anterior insula bilaterally, anterior mid-cingulate cortex (aMCC), bilateral thalamus, and contralateral posterior insula were observed. The time courses of CBF revealed significant differences in the activation pattern during tonic pain. In particular, a more rapid return to baseline in aMCC versus insula was interpreted as a preferential decrease in the affective component of pain. This conclusion was supported by the strong correlation between pain intensity ratings and CBF in the contralateral insula (R(2)=0.911, p<0.01), which is a region believed to be responsible for pain intensity processing.

  12. Belowground plant development measured with magnetic resonance imaging (MRI: exploiting the potential for non-invasive trait quantification using sugar beet as a proxy

    Directory of Open Access Journals (Sweden)

    Ralf eMetzner

    2014-09-01

    Full Text Available Both structural and functional properties of belowground plant organs are critical for the development and yield of plants but, compared to the shoot, much more difficult to observe due to soil opacity. Many processes concerning the belowground plant performance are not fully understood, in particular spatial and temporal dynamics and their interrelation with environmental factors. We used Magnetic Resonance Imaging (MRI as a noninvasive method to evaluate which traits can be measured when a complex plant organ is monitored in-vivo while growing in the soil. We chose sugar beet (Beta vulgaris ssp. vulgaris as a model system. The beet consists mainly of root tissues, is rather complex regarding tissue structure and responses to environmental factors, and thereby a good object to test the applicability of MRI for 3D phenotyping approaches. Over a time period of up to 3 months, traits such as beet morphology or anatomy were followed in the soil and the effect of differently sized pots on beet fresh weight calculated from MRI data was studied. There was a clear positive correlation between the pot size and the increase in fresh weight of a sugar beet over time. Since knowledge of the development of internal beet structures with several concentric cambia, vascular and parenchyma rings is still limited, we consecutively acquired 3D volumetric images on individual plants using the MRI contrast parameter T2 to map the development of rings at the tissue level. This demonstrates that MRI provides versatile protocols to non-invasively measure plant traits in the soil. It opens new avenues to investigate belowground plant performance under adverse environmental conditions such as drought, nutrient shortage or soil compaction to seek for traits of belowground organs making plants more resilient to stress.

  13. Belowground plant development measured with magnetic resonance imaging (MRI): exploiting the potential for non-invasive trait quantification using sugar beet as a proxy

    Science.gov (United States)

    Metzner, Ralf; van Dusschoten, Dagmar; Bühler, Jonas; Schurr, Ulrich; Jahnke, Siegfried

    2014-01-01

    Both structural and functional properties of belowground plant organs are critical for the development and yield of plants but, compared to the shoot, much more difficult to observe due to soil opacity. Many processes concerning the belowground plant performance are not fully understood, in particular spatial and temporal dynamics and their interrelation with environmental factors. We used Magnetic Resonance Imaging (MRI) as a noninvasive method to evaluate which traits can be measured when a complex plant organ is monitored in-vivo while growing in the soil. We chose sugar beet (Beta vulgaris ssp. vulgaris) as a model system. The beet consists mainly of root tissues, is rather complex regarding tissue structure and responses to environmental factors, and thereby a good object to test the applicability of MRI for 3D phenotyping approaches. Over a time period of up to 3 months, traits such as beet morphology or anatomy were followed in the soil and the effect of differently sized pots on beet fresh weight calculated from MRI data was studied. There was a clear positive correlation between the pot size and the increase in fresh weight of a sugar beet over time. Since knowledge of the development of internal beet structures with several concentric cambia, vascular and parenchyma rings is still limited, we consecutively acquired 3D volumetric images on individual plants using the MRI contrast parameter T2 to map the development of rings at the tissue level. This demonstrates that MRI provides versatile protocols to non-invasively measure plant traits in the soil. It opens new avenues to investigate belowground plant performance under adverse environmental conditions such as drought, nutrient shortage, or soil compaction to seek for traits of belowground organs making plants more resilient to stress. PMID:25278947

  14. Improved measurement of labile proton concentration-weighted chemical exchange rate (kws) with experimental factor-compensated and T1-normalized quantitative chemical exchange saturation transfer (CEST) MRI

    Science.gov (United States)

    Wu, Renhua; Liu, Charng-Ming; Liu, Philip K; Sun, Phillip Zhe

    2012-01-01

    Chemical exchange saturation transfer (CEST) MRI enables measurement of dilute CEST agents and microenvironment properties such as pH and temperature, holding great promise for in vivo applications. However, because of confounding concomitant RF irradiation and relaxation effects, the CEST-weighted MRI contrast may not fully characterize the underlying CEST phenomenon. We postulated that the accuracy of quantitative CEST MRI could be improved if the experimental factors (labeling efficiency and RF spillover effect) were estimated and taken into account. Specifically, the experimental factor was evaluated as a function of exchange rate and CEST agent concentration ratio, which remained relatively constant for intermediate RF irradiation power levels. Hence, the experimental factors can be calculated based on the reasonably estimated exchange rate and labile proton concentration ratio, which significantly improved quantification. The simulation was confirmed with Creatine phantoms of serially varied concentration titrated to the same pH, whose reverse exchange rate (kws) was found to be linearly correlated with the concentration. In summary, the proposed solution provides simplified yet reasonably accurate quantification of the underlying CEST system, which may help guide the ongoing development of quantitative CEST MRI. PMID:22649044

  15. Clinical usefulness of nuclear magnetic resonance imaging (MRI) in discriminating different pathological changes in two patients with lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Yoshiaki; Shioya, Sumie; Ohta, Yasuyo; Yamabayashi, Hajime; Haida, Munetaka

    1988-01-01

    Two patients of lung cancer who developed homogeneous opacities in the left upper lung field were evaluated by MRI. Case 1 was a 46-year-old man with Horner's sign on the left side. MRI saggital images disclosed invasion to adjacent tissues which was not clearly demonstrated by conventional CT. Case 2 was a 66-year-old man with poorly differentiated squamous cell carcinoma. MRI revealed two different components in the homogeneous lesion which was not detected by CT. The difference in strength of signal intensity between each lesion was very prominent both in the T/sub 2/ weighted image (i.e., long SE) and in the IR image, not in the short SE image. This investigation presents two patients with lung cancer in whom MRI was found useful in distinguishing different lung pathological fundings. With conventional chest roentgenogram and CT, homogeneous opacities in the left upper lung were demonstrated. MRI revealed two components with different signal intensity in the homogeneous lesions. The difference was further enhanced in T/sub 2/ weighted MRI. In vitro measurement of T/sub 1/ and T/sub 2/ values of lung pathological tissues strongly suggested that one of two components corresponds to tumor and the other to non-tumor lesion. The results indicate that the T/sub 2/ weighted MRI is useful to distinguish different pathological changes in the lung.

  16. Measurement of SUVs-Maximum for Normal Region Using VOI in PET/MRI and PET/CT

    Directory of Open Access Journals (Sweden)

    Jeong Kyu Park

    2014-01-01

    Full Text Available The purpose of this research is to establish an overall data set associated with the VOI (Volume of Interest, which is available for simultaneous assessment of PET/MRI and PET/CT regardless of the use of contrast media. The participants as objects of this investigation are 26 healthy examinees in Korea, SUV (standardized-uptake-values-maximum evaluation for whole-body F-18 FDG (fluorodeoxyglucose PET/MRI image using VOI of normal region has exhibited very significant difference to that for whole-body F-18 FDG PET/CT image (significant probability value (P0.8. It is shown that one needs to decide SUVs-maximum for PET/MRI with the reduction of 25.0~26.4% from their evaluated value and needs to decide with the reduction of 28.8~29.4% in the same situation but with the use of contrast media. The use of SUVLBM-maximum (SUVLean Body Mass-maximum is very advantageous in reading overall image of PET/CT and PET/MRI to medical doctors and researchers, if we consider its convenience and efficiency. We expect that this research enhances the level of the early stage accurate diagnosis with whole-body images of PET/MRI and PET/CT.

  17. Reproducibility of pulmonary blood flow measurements by phase-contrast MRI using different 1.5 T MR scanners at two institutions

    Science.gov (United States)

    Iraha, Rin; Tsuchiya, Nanae; Yamashiro, Tsuneo; Iwasawa, Tae

    2017-01-01

    Background Magnetic resonance imaging (MRI) can be beneficial for diagnosis of disease by offering quantitative information. However, reproducibility can be a major problem when there is a numerical threshold in multi-institution, multi-vendor situations. Purpose To measure pulmonary blood flow with phase-contrast (PC) imaging using two different MR scanners (1.5 T) at different institutions in the same participants and to examine the reproducibility of the measurements. Material and Methods Participants were 10 healthy volunteers (5 men; age range, 27–36 years). The measurements included the mean and maximal blood velocities, the mean blood flow volume, and the acceleration time and volume (AT and AV), derived from the time-flow curve of the PC-MRI. Simultaneously obtained maximal, minimal, and mean areas from regions of interest set in the pulmonary artery were also calculated. In order to calculate the reproducibility of the quantitative variables, intra-class correlation coefficients (ICCs) were employed. When an adequate ICC was obtained, Bland–Altman analysis was conducted to identify any systematic bias. Results The ICCs were almost perfect for the mean blood flow volume and the AV (r = 0.82 and 0.80), and were substantial in the mean and maximal areas, and the AT (r = 0.63, 0.74, and 0.64, respectively). However, there was a fixed bias in the area measurement between the two scanners. Also, the AV had a proportional bias. Conclusion Our results reveal that various indices derived from PC-MRI on different MR scanners are promising as common indices for pulmonary flow assessment. Research and clinical use of PC-MRI for the pulmonary artery is expected to extend to multi-institution situations. PMID:28210495

  18. Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Rostrup, Egill; Garde, Ellen;

    2001-01-01

    Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined...... was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE-EPI measured a significant...... increase in CBF and CBV in response to ACZ, while SE-EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE-EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE-EPI and change in ICA flow. In conclusion...

  19. Resting fMRI measures are associated with cognitive deficits in schizophrenia assessed by the MATRICS consensus cognitive battery

    Science.gov (United States)

    He, Hao; Bustillo, Juan; Du, Yuhui; Yu, Qingbao; Jones, Thomas R.; Jiang, Tianzi; Calhoun, Vince D.; Sui, Jing

    2015-03-01

    The cognitive deficits of schizophrenia are largely resistant to current treatment, and are thus a life-long burden to patients. The MATRICS consensus cognitive battery (MCCB) provides a reliable and valid assessment of cognition across a comprehensive set of cognitive domains for schizophrenia. In resting-state fMRI, functional connectivity associated with MCCB has not yet been examined. In this paper, the interrelationships between MCCB and the abnormalities seen in two types of functional measures from resting-state fMRI—fractional amplitude of low frequency fluctuations (fALFF) and functional network connectivity (FNC) maps were investigated in data from 47 schizophrenia patients and 50 age-matched healthy controls. First, the fALFF maps were generated and decomposed by independent component analysis (ICA), and then the component showing the highest correlation with MCCB composite scores was selected. Second, the whole brain was separated into functional networks by group ICA, and the FNC maps were calculated. The FNC strengths with most significant correlations with MCCB were displayed and spatially overlapped with the fALFF component of interest. It demonstrated increased cognitive performance associated with higher fALFF values (intensity of regional spontaneous brain activity) in prefrontal regions, inferior parietal lobe (IPL) but lower ALFF values in thalamus, striatum, and superior temporal gyrus (STG). Interestingly, the FNC showing significant correlations with MCCB were in well agreement with the activated regions with highest z-values in fALFF component. Our results support the view that functional deficits in distributed cortico-striato-thalamic circuits and inferior parietal lobe may account for several aspects of cognitive impairment in schizophrenia.

  20. Automating measurement of subtle changes in articular cartilage from MRI of the knee by combining 3D image registration and segmentation

    Science.gov (United States)

    Lynch, John A.; Zaim, Souhil; Zhao, Jenny; Peterfy, Charles G.; Genant, Harry K.

    2001-07-01

    In osteoarthritis, articular cartilage loses integrity and becomes thinned. This usually occurs at sites which bear weight during normal use. Measurement of such loss from MRI scans, requires precise and reproducible techniques, which can overcome the difficulties of patient repositioning within the scanner. In this study, we combine a previously described technique for segmentation of cartilage from MRI of the knee, with a technique for 3D image registration that matches localized regions of interest at followup and baseline. Two patients, who had recently undergone meniscal surgery, and developed lesions during the 12 month followup period were examined. Image registration matched regions of interest (ROI) between baseline and followup, and changes within the cartilage lesions were estimate to be about a 16% reduction in cartilage volume within each ROI. This was more than 5 times the reproducibility of the measurement, but only represented a change of between 1 and 2% in total femoral cartilage volume. Changes in total cartilage volume may be insensitive for quantifying changes in cartilage morphology. A combined used of automated image segmentation, with 3D image registration could be a useful tool for the precise and sensitive measurement of localized changes in cartilage from MRI of the knee.

  1. Effects of repeatability measures on results of fMRI sICA: a study on simulated and real resting-state effects.

    Science.gov (United States)

    Remes, Jukka J; Starck, Tuomo; Nikkinen, Juha; Ollila, Esa; Beckmann, Christian F; Tervonen, Osmo; Kiviniemi, Vesa; Silven, Olli

    2011-05-15

    Spatial independent components analysis (sICA) has become a widely applied data-driven method for fMRI data, especially for resting-state studies. These sICA approaches are often based on iterative estimation algorithms and there are concerns about accuracy due to noise. Repeatability measures such as ICASSO, RAICAR and ARABICA have been introduced as remedies but information on their effects on estimates is limited. The contribution of this study was to provide more of such information and test if the repeatability analyses are necessary. We compared FastICA-based ordinary and repeatability approaches concerning mixing vector estimates. Comparisons included original FastICA, FSL4 Melodic FastICA and original and modified ICASSO. The effects of bootstrapping and convergence threshold were evaluated. The results show that there is only moderate improvement due to repeatability measures and only in the bootstrapping case. Bootstrapping attenuated power from time courses of resting-state network related ICs at frequencies higher than 0.1 Hz and made subsets of low frequency oscillations more emphasized IC-wise. The convergence threshold did not have a significant role concerning the accuracy of estimates. The performance results suggest that repeatability measures or strict converge criteria might not be needed in sICA analyses of fMRI data. Consequently, the results in existing sICA fMRI literature are probably valid in this sense. A decreased accuracy of original bootstrapping ICASSO was observed and corrected by using centrotype mixing estimates but the results warrant for thorough evaluations of data-driven methods in general. Also, given the fMRI-specific considerations, further development of sICA methods is strongly encouraged. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. 海马结构的磁共振信号测量%MRI Signal Measurement of Hippocampal Formation

    Institute of Scientific and Technical Information of China (English)

    杜绪仓; 王泽忠; 鱼博浪; 任惠民; 胡海涛; 刘勇

    2001-01-01

    Objective To define the range of the normal values of MRI signals of hippocampal formation(HPF) for the diagnosis of early stage Alzheimer's disease and hippocampal sclerosis.Methods MRI signals of 254 normal adults were measured on the transverse section.Results HPF signal intensities were:T1 relaxation times,629±73 ms;T2 relaxation times,83±5.5 ms;and proton density value,5978±651.The T2 value range(χ±2S)was 72~94 ms,and mean 83 ms.T2 value greater than 104 ms will be associated with evidence of hippocampal pathologic changes.The mixed signal intensity of T2WI(30,60,120)were:3907±407,2657±347,1288±174.The signal intensity ratios of T2WI were:1.02,1.07,1.13.Conclusion As for the histological features of temporal lobe cortex and HPF,T1relaxation times and proton density values are matched but T2 relaxation times of HPF are relatively longer.%目的确定正常成年人海马结构(HPF)的磁共振信号范围,用于HS及AD的早期诊断及鉴别诊断。方法 MRI横切位定量测量了254例成年国人(年龄18~76岁)的HPF的磁共振信号。结果正常HPF的T1驰豫时间、T2驰豫时间及质子密度值分别为(629±73)ms,(83±5.5)ms,5978±651。正常T2值范围(χ±2S)为:72~94 ms。正常HPF T1WI及T2WI各回波(30、60、120)绝对信号值分别为:2263±258、3907±407、2657±347、1288±174。与颞叶皮质的相对信号强度(SIR)为:T1WI,0.98。T2WI分别为1.02、1.07、1.13。结论与颞叶皮质相比,HPF的信号特点为:T1值及质子密度值相当,T2值较长。

  3. MRI of the Prostate

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Prostate Magnetic resonance imaging (MRI) of the prostate ... limitations of MRI of the Prostate? What is MRI of the Prostate? Magnetic resonance imaging (MRI) is ...

  4. Correlation between Heart, Liver and Pancreas Hemosiderosis Measured by MRI T2* among Thalassemia Major Patients from Iran.

    Science.gov (United States)

    Azarkeivan, Azita; Hashemieh, Mozhgan; Shirkavand, Afshan; Sheibani, Kourosh

    2016-02-01

    Major thalassemia patients need lifelong transfusions. The consequence of these repeated transfusions is iron accumulation in different organs. The main aim of the present study was to investigate the correlation between heart, liver and pancreas hemosiderosis in thalassemic patients from Iran. This cross-sectional study was conducted on 164 major thalassemia patients at Zafar Adult Thalassemia Center, a referral thalassemia center in Tehran, Iran, from May to November 2014.  All patients were on regular blood transfusion at 2-4 week intervals to keep their hemoglobin at a level of 7-9 gr/dL before each transfusion. Demographic data were gathered from patients' history. MRI T2* of liver, heart and pancreas were performed for all patients. There were a moderate correlation between pancreatic T2* and cardiac T2* relaxation times (r = 0.42, P pancreas and liver (r = 0.41, P pancreas and liver T2* relaxation times indicate that relying on liver MRI T2* to predict the exact condition of pancreas or heart iron overload might not be a reliable approach in thalassemia major patients. Our findings suggest the advantage of using pancreas and heart MRI T2* as a non-invasive method for estimation of iron overload instead of relying on liver MRI T2*.

  5. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: an international multicenter reliability study using computerized MRI erosion volume measurements

    DEFF Research Database (Denmark)

    Bird, P; Ejbjerg, B; McQueen, F;

    2003-01-01

    Scoring erosions on magnetic resonance imaging (MRI) is one method of estimating damage in patients with rheumatoid arthritis (RA), but it has limitations. The aim of this pilot study was to assess the feasibility and inter-reader reliability of computer assisted erosion volume estimation...

  6. Cortical phase changes measured using 7-T MRI in subjects with subjective cognitive impairment, and their association with cognitive function

    NARCIS (Netherlands)

    Rooden, van Sanneke; Buijs, Mathijs; Vliet, van Marjolein E.; Versluis, Maarten J.; Webb, Andrew G.; Oleksik, Ania M.; Wiel, van de Lotte; Middelkoop, Huub A.M.; Blauw, Gerard Jan; Weverling-Rynsburger, Annelies W.E.; Goos, Jeroen D.C.; Flier, van der Wiesje M.; Koene, Ted; Scheltens, Philip; Barkhof, Frederik; Nieuwerth-van de Rest, Ondine; Slagboom, P.E.; Buchem, van Mark A.; Grond, van der Jeroen

    2016-01-01

    Studies have suggested that, in subjects with subjective cognitive impairment (SCI), Alzheimer's disease (AD)-like changes may occur in the brain. Recently, an in vivo study has indicated the potential of ultra-high-field MRI to visualize amyloid-beta (Aβ)-associated changes in the cortex in

  7. Comparison of MRI and DXA to measure muscle size and age-related atrophy in thigh muscles.

    Science.gov (United States)

    Maden-Wilkinson, T M; Degens, H; Jones, D A; McPhee, J S

    2013-09-01

    Magnetic resonance imaging (MRI) and dual-energy x-ray absorptiometry (DXA) were used to examine the thigh lean mass in young and old men and women. A whole-body DXA scan was used to estimate thigh lean mass in young (20 men; 22.4±3.1y; 18 women; 22.1±2.0y) and older adults (25 men; 72.3±4.9y; 28 women; 72.0±4.5y). Thigh lean mass determined with a thigh scan on the DXA or full thigh MRI scans were compared. Although the thigh lean mass quantified by DXA and MRI in young and older participants were correlated (R(2)=0.88; pmuscles in the older than young individuals, while the other thigh muscles were only 18% smaller. DXA underestimates the age-related loss of thigh muscle mass in comparison to MRI. The quadriceps muscles were more susceptible to age-related atrophy compared with other thigh muscles.

  8. Comparison of serial serum ferritin measurements and liver iron concentration assessed by MRI in adult transfused patients with sickle cell disease.

    Science.gov (United States)

    Tsitsikas, Dimitris A; Nzouakou, Ruben; Ameen, Venus; Sirigireddy, Bala; Amos, Roger J

    2014-02-01

    Transfused patients with sickle cell disease (SCD) are at risk of iron overload and identifying such patients is important to prevent associated complications. Our aim was to assess the efficacy of serial serum ferritin (SF) measurements in identifying patients with hepatic iron overload as assessed by liver MRI and its usefulness in guiding decision making regarding chelation therapy. We retrospectively compared the results of 49 liver MRI scans (LS) with the median serum ferritin (MSF) values for 28 patients in our institution. We found a nonlinear increment of MSF with increasing liver iron concentration (LIC). 18.4% and 47.4% of abnormal LSs corresponded to MSF serum ferritin measurements in adult transfused patients with sickle cell disease have a low sensitivity for identifying patients with iron overload and are of limited value in guiding decision making regarding initiation or monitoring of chelation therapy. The iron status of such high risk patients should be assessed by more definitive ways such as MRI. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Assessment of EchoMRI-AH versus dual-energy X-ray absorptiometry by iDXA to measure human body composition.

    Science.gov (United States)

    Marlatt, K L; Greenway, F L; Ravussin, E

    2017-04-01

    Comparison of percent fat mass across different body composition analysis devices is important given variation in technology accuracy and precision, as well as the growing need for cross-validation of devices often applied across longitudinal studies. We compared EchoMRI-AH and Lunar iDXA quantification of percent body fat (PBF) in 84 adults (43M, 41F), with the mean age 39.7±15.9 years and body mass index (BMI) 26.2±5.3 kg/m(2). PBF correlated strongly between devices (r>0.95, P<0.0001). A prediction equation was derived in half of the subjects, and the other half were used to cross-validate the proposed equation (EchoMRI-AH PBF=[(0.94 × iDXA PBF)+(0.14 × Age)+(3.3 × Female)-8.83). The mean PBF difference (predicted-measured) in the validation group was not different from 0 (diff=0.27%, 95% confidence interval: -0.42-0.96, P=0.430). Bland-Altman plots showed a bias with higher measured PBF on EchoMRI-AH versus iDXA in all 84 subjects (β=0.13, P<0.0001). The proposed prediction equation was valid in our cross-validation sample, and it has the potential to be applied across multicenter studies.

  10. Dynamic regional phase synchrony (DRePS): An Instantaneous Measure of Local fMRI Connectivity Within Spatially Clustered Brain Areas.

    Science.gov (United States)

    Omidvarnia, Amir; Pedersen, Mangor; Walz, Jennifer M; Vaughan, David N; Abbott, David F; Jackson, Graeme D

    2016-05-01

    Dynamic functional brain connectivity analysis is a fast expanding field in computational neuroscience research with the promise of elucidating brain network interactions. Sliding temporal window based approaches are commonly used in order to explore dynamic behavior of brain networks in task-free functional magnetic resonance imaging (fMRI) data. However, the low effective temporal resolution of sliding window methods fail to capture the full dynamics of brain activity at each time point. These also require subjective decisions regarding window size and window overlap. In this study, we introduce dynamic regional phase synchrony (DRePS), a novel analysis approach that measures mean local instantaneous phase coherence within adjacent fMRI voxels. We evaluate the DRePS framework on simulated data showing that the proposed measure is able to estimate synchrony at higher temporal resolution than sliding windows of local connectivity. We applied DRePS analysis to task-free fMRI data of 20 control subjects, revealing ultra-slow dynamics of local connectivity in different brain areas. Spatial clustering based on the DRePS feature time series reveals biologically congruent local phase synchrony networks (LPSNs). Taken together, our results demonstrate three main findings. Firstly, DRePS has increased temporal sensitivity compared to sliding window correlation analysis in capturing locally synchronous events. Secondly, DRePS of task-free fMRI reveals ultra-slow fluctuations of ∼0.002-0.02 Hz. Lastly, LPSNs provide plausible spatial information about time-varying brain local phase synchrony. With the DRePS method, we introduce a framework for interrogating brain local connectivity, which can potentially provide biomarkers of human brain function in health and disease. Hum Brain Mapp 37:1970-1985, 2016. © 2016 Wiley Periodicals, Inc.

  11. MRI zoo

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard....... MRI was done using a Philips Achieva 1.5 T system and CT was performed using a Siemens Somatom system. Axial and sagittal slices were acquired using standard T1w and T2w MRI sequences, and visualization was made using the Mistar software (Apollo Imaging Technology, Melbourne, Australia). Images were...

  12. MRI of the cardiomyopathies

    Energy Technology Data Exchange (ETDEWEB)

    Di Cesare, Ernesto E-mail: ernesto.dicesare@cc.univaq.it

    2001-06-01

    We examined the potentialities of Magnetic resonance imaging (MRI) in the evaluation of the main cardiomyopathies: hypertrophic, dilated, restrictive and arrhythmogenic right ventricular. The hypertrophic cardiomyopathy is generally adequately investigated by echocardiography, that well defines the myocardial thickening and the obstruction of the left ventricular output. However, by echocardiography we still have difficulties in the evaluation of the apex of the left ventricle and the right ventricle involvement. MRI provides a complete evaluation of the heart with a clear evidence also of the echocardiographic dark zones by means of a clear evidence of the apex of the right ventricle. The dilated form is also well investigated by MRI that provides a clear evaluation of the volumes, mass and ejection fraction by means of the 3D analysis including conditions of the ventricular remodelling. Moreover, this technique helps in the differential diagnosis of acute myocarditis. In the acute phase of myocarditis (first 2 weeks), in fact, the myocardium produces high signal intensity on the T2 weighted sequences due to the presence of oedema. The third form of cardiomyopathy is the restrictive one, characterised by reduced diastolic filling and diastolic volume, normality of the systolic function and parietal thickness, interstitial fibrosis and enlargement of both atria. The mean potentiality of MRI is related to the differential diagnosis with constrictive pericarditis. Only in the former, the pericardium appears irregularly thickened with areas exceeding 4 mm of pericardial thickness. Finally, the right ventricular arrhythmogenic cardiomyopathy represents the main indication to MRI evaluation. With this imaging modality we are can obtain a clear morpho-functional evaluation of the right ventricle and distinguish the intramyocardial adipose substitution characterised by areas of high signal in the myocardium.

  13. Fractionated manganese injections: effects on MRI contrast enhancement and physiological measures in C57BL/6 mice.

    Science.gov (United States)

    Grünecker, Barbara; Kaltwasser, Sebastian F; Peterse, Yorick; Sämann, Philipp G; Schmidt, Mathias V; Wotjak, Carsten T; Czisch, Michael

    2010-10-01

    Manganese-enhanced MRI (MEMRI) is an increasingly used imaging method in animal research, which enables improved T(1)-weighted tissue contrast. Furthermore accumulation of manganese in activated neurons allows visualization of neuronal activity. However, at higher concentrations manganese (Mn2+) exhibits toxic side effects that interfere with the animals' behaviour and well-being. Therefore, when optimizing MEMRI protocols, a compromise has to be found between minimizing side effects and intensifying image contrast. Recently, a low concentrated fractionated Mn2+ application scheme has been proposed as a promising alternative. In this study, we investigated effects of different fractionated Mn2+ dosing schemes on vegetative, behavioural and endocrine markers, and MEMRI signal contrast in C57BL/6N mice. Measurements of the animals' well-being included telemetric monitoring of body temperature and locomotion, control of weight and observation of behavioural parameters during the time course of the injection protocols. Corticosterone levels after Mn2+ application served as endocrine marker of the stress response. We compared three MnCl2  x 4H2O application protocols: 3 times 60 mg/kg with an inter-injection interval of 48 h, six times 30 mg/kg with an inter-injection interval of 48 h, and 8 times 30 mg/kg with an inter-injection interval of 24 h (referred to as 3 x 60/48, 6 x 30/48 and 8 x 30/24, respectively). Both the 6 x 30/48 and the 8 x 30/24 protocols showed attenuated effects on animals' well-being as compared to the 3 x 60/48 scheme. Best MEMRI signal contrast was observed for the 8 x 30/24 protocol. Together, these results argue for a fractionated application scheme such as 30 mg/kg every 24 h for 8 days to provide sufficient MEMRI signal contrast while minimizing toxic side effects and distress.

  14. SU-E-J-236: Audiovisual Biofeedback Improves Breath-Hold Lung Tumor Position Reproducibility Measured with 4D MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D; Pollock, S; Keall, P [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW (Australia); Greer, P [School of Mathematical and Physical Sciences, The University of Newcastle, Newcastle, NSW (Australia); Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW (Australia); Lapuz, C; Ludbrook, J [Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW (Australia); Kim, T [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW (Australia); Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA (United States)

    2015-06-15

    Purpose: Audiovisual biofeedback breath-hold (AVBH) was employed to reproduce tumor position on inhale and exhale breath-holds for 4D tumor information. We hypothesize that lung tumor position will be more consistent using AVBH compared with conventional breath-hold (CBH). Methods: Lung tumor positions were determined for seven lung cancer patients (age: 25 – 74) during to two separate 3T MRI sessions. A breathhold training session was performed prior to the MRI sessions to allow patients to become comfortable with AVBH and their exhale and inhale target positions. CBH and AVBH 4D image datasets were obtained in the first MRI session (pre-treatment) and the second MRI session (midtreatment) within six weeks of the first session. Audio-instruction (MRI: Siemens Skyra) in CBH and verbal-instruction (radiographer) in AVBH were used. A radiation oncologist contoured the lung tumor using Eclipse (Varian Medical Systems); tumor position was quantified as the centroid of the contoured tumor after rigid registration based on vertebral anatomy across two MRI sessions. CBH and AVBH were compared in terms of the reproducibility assessed via (1) the difference between the two exhale positions for the two sessions and the two inhale positions for the sessions. (2) The difference in amplitude (exhale to inhale) between the two sessions. Results: Compared to CBH, AVBH improved the reproducibility of two exhale (or inhale) lung tumor positions relative to each other by 33%, from 6.4±5.3 mm to 4.3±3.0 mm (p=0.005). Compared to CBH, AVBH improved the reproducibility of exhale and inhale amplitude by 66%, from 5.6±5.9 mm to 1.9±1.4 mm (p=0.005). Conclusions: This study demonstrated that audiovisual biofeedback can be utilized for improving the reproducibility of breath-hold lung tumor position. These results are advantageous towards achieving more accurate emerging radiation treatment planning methods, in addition to imaging and treatment modalities utilizing breath

  15. Pediatric MRI

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIH Study of Normal Brain Development is a longitudinal study using anatomical MRI, diffusion tensor imaging (DTI), and MR spectroscopy (MRS) to map pediatric...

  16. Knee MRI

    Science.gov (United States)

    ... air-conditioned and well-lit. Some scanners have music to help you pass the time. When the ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  17. Cerebral blood flow measured by arterial-spin labeling MRI: A useful biomarker for characterization of minimal hepatic encephalopathy in patients with cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210016 (China); Zhang, Long Jiang, E-mail: kevinzhlj@163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Zhong, Jianhui [Department of Imaging Sciences, University of Rochester School of Medicine and Dentistry, Box648, 601 Elmwood Avenue, Rochester, NY 14642-8648 (United States); Wang, Ze [Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3900 Chestnut St., Philadelphia, PA 19104 (United States); Qi, Rongfeng; Shi, Donghong [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Lu, Guang Ming, E-mail: cjr.luguangming@vip.163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China)

    2013-11-01

    Purpose: To investigate the role of arterial-spin labeling (ASL) MRI to non-invasively characterize the patterns of cerebral blood flow (CBF) changes in cirrhotic patients and to assess the potential of ASL MRI to characterize minimal hepatic encephalopathy (MHE). Materials and methods: This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Thirty six cirrhosis patients without overt hepatic encephalopathy (16 MHE patients and 20 non hepatic encephalopathy (non-HE) patients) and 25 controls underwent ASL MRI, and CBF was measured for each subject. One-way ANOCOVA test with age and gender as covariences was used to compare CBF difference among three groups, and post hoc analysis was performed between each two groups. Region-based correlation analysis was applied between Child–Pugh score, venous blood ammonia level, neuropsychological tests and CBF values in cirrhosis patients. Receiver operator characteristic (ROC) analysis was used for assessing CBF measurements in ASL MRI to differentiate MHE from non-HE patients. Results: The gray matter CBF of MHE patients (71.09 ± 11.88 mL min{sup −1} 100 g{sup −1}) was significantly higher than that of non-HE patients (55.28 ± 12.30 mL min{sup −1} 100 g{sup −1}, P < 0.01) and controls (52.09 ± 9.27 mL min{sup −1} 100 g{sup −1}, P < 0.001). Voxel-wise ANOCOVA results showed that CBFs were significantly different among three groups in multiple gray matter areas (P < 0.05, Bonferroni corrected). Post hoc comparisons showed that CBF of these brain regions was increased in MHE patients compared with controls and non-HE patients (P < 0.05, Bonferroni corrected). CBF of the right putamen was of the highest sensitivity (93.8%) and moderate specificity (75.0%) for characterization of MHE when using the cutoff value of 50.57 mL min{sup −1} 100 g{sup −1}. CBFs in the bilateral median cingulate gyri, left supramarginal gyrus, right angular gyrus, right

  18. Perfusion MRI (dynamic susceptibility contrast imaging) with different measurement approaches for the evaluation of blood flow and blood volume in human gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, H. (Den Sundhedsfaglige Kandidatuddannelse, Aarhus Universitet Bygning 1264, Aarhus (Denmark); University College Nordjylland, Aalborg (Denmark)), Email: hnt@ucn.dk; Steffensen, E. (Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark)); Larsson, E. M. (Aalborg Hospital/Aarhus University Hospital, Department of Radiology, Aalborg (Denmark); Uppsala University Hospital, Department of Radiology, Uppsala (Sweden))

    2012-02-15

    Background. Perfusion magnetic resonance imaging (MRI) is increasingly used in the evaluation of brain tumors. Relative cerebral blood volume (rCBV) is usually obtained by dynamic susceptibility contrast (DSC) MRI using normal appearing white matter as reference region. The emerging perfusion technique arterial spin labelling (ASL) presently provides measurement only of cerebral blood flow (CBF), which has not been widely used in human brain tumor studies. Purpose. To assess if measurement of blood flow is comparable with measurement of blood volume in human biopsy-proven gliomas obtained by DSC-MRI using two different regions for normalization and two different measurement approaches. Material and Methods. Retrospective study of 61 patients with different types of gliomas examined with DSC perfusion MRI. Regions of interest (ROIs) were placed in tumor portions with maximum perfusion on rCBF and rCBV maps, with contralateral normal appearing white matter and cerebellum as reference regions. Larger ROIs were drawn for histogram analyses. The type and grade of the gliomas were obtained by histopathology. Statistical comparison was made between diffuse astrocytomas, anaplastic astrocytomas, and glioblastomas. Results. rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r = 0.60) and to the cerebellum (r = 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated (0.61 < r < 0.93), whereas for kurtosis and peak height, the correlation coefficient was about 0.3 when comparing rCBF and rCBV values for the same reference region. Neither rCBF nor rCBV quantification provided a statistically significant difference between the three types of gliomas. However, both rCBF and rCBV tended to increase with tumor grade and to be lower in patients who had undergone resection/treatment. Conclusion. rCBF measurements normalized to white matter

  19. Distinguishing the Sciences: For Nursing

    Directory of Open Access Journals (Sweden)

    Catherine Green

    2014-06-01

    Full Text Available The article explores the problem of nursing as a practical discipline and suggests that there are several kinds of nursing science. Following the lead of Jacques Maritain and Yves R. Simon, the authoress begins with an account of the distinguishing characteristics of theoretical knowledge, to which the term “science” has historically been applied, and distinguishes it from practical knowledge or prudence. Next she reviews Maritain and Simon’s discussion of two intermediate levels of inquiry that share some characteristics of both science and practical knowledge. Finally, using the writings of several nurse theorists whose seminal ideas in this area have established a basis for nurse theorist’s discussion of these issues, she distinguishes four kinds of nursing inquiry which range from the very theoretical to the very practical.

  20. Right temporal cortical hypertrophy in resilience to trauma: an MRI study

    OpenAIRE

    Sevenius Nilsen, André; Hilland, Eva; Kogstad, Norunn; Heir, Trond; Hauff, Edvard; Lien, Lars; Endestad, Tor

    2016-01-01

    Background In studies employing physiological measures such as magnetic resonance imaging (MRI), it is often hard to distinguish what constitutes risk-resilience factors to posttraumatic stress disorder (PTSD) following trauma exposure and what the effects of trauma exposure and PTSD are. Objective We aimed to investigate whether there were observable morphological differences in cortical and sub-cortical regions of the brain, 7–8 years after a single potentially traumatic event. Methods Twen...

  1. Measurement of diaphragmatic length during the breathing cycle by dynamic MRI: comparison between healthy adults and patients with an intrathoracic tumor

    Energy Technology Data Exchange (ETDEWEB)

    Plathow, Christian; Fink, Christian; Ley, Sebastian; Puderbach, Michael; Eichinger, Monica; Kauczor, Hans-Ulrich [Department of Radiology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120, Heidelberg (Germany); Schmaehl, Astrid [Department of Diagnostic Radiology, Clinic for Thoracic Diseases, Heidelberg (Germany)

    2004-08-01

    The purpose of this study was to assess diaphragmatic length and shortening during the breathing cycle in healthy volunteers and patients with a lung tumor using dynamic MRI (dMRI). In 15 healthy volunteers and 28 patients with a solitary lung tumor, diaphragmatic motion and length were measured during the breathing cycle using a trueFISP sequence (three images per second in the coronal and sagittal plane). Time-distance curves and maximal length reduction (= shortening) of the diaphragm were calculated. The influence of tumor localization on diaphragmatic shortening was examined. In healthy volunteers maximal diaphragmatic shortening was 30% in the coronal and 34% in the sagittal orientation, with no difference between both hemithoraces. Tumors of the upper and middle lung region did not affect diaphragmatic shortening. In contrast, tumors of the lower lung region changed shortening significantly (P<0.05). In hemithoraces with a tumor in the lower region, shortening was 18% in the coronal and 19% in the sagittal plane. The ratio of diaphragmatic length change from inspiration to expiration changed significantly from healthy subjects (inspiration length >> expiratory length, P<0.05) to patients with a tumor in the lower lung region (inspiratory length = expiratory length). dMRI is a simple, non-invasive method to evaluate diaphragmatic motion and shortening in volunteers and patients during the breathing cycle. Tumors of the lower lung region have a significant influence on shortening of the diaphragm. (orig.)

  2. Regional and voxel-wise comparisons of blood flow measurements between dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and arterial spin labeling (ASL) in brain tumors.

    Science.gov (United States)

    White, Carissa M; Pope, Whitney B; Zaw, Taryar; Qiao, Joe; Naeini, Kourosh M; Lai, Albert; Nghiemphu, Phioanh L; Wang, J J; Cloughesy, Timothy F; Ellingson, Benjamin M

    2014-01-01

    The objective of the current study was to evaluate the regional and voxel-wise correlation between dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) measurement of cerebral blood flow (CBF) in patients with brain tumors. Thirty patients with histologically verified brain tumors were evaluated in the current study. DSC-MRI was performed by first using a preload dose of gadolinium contrast, then collecting a dynamic image acquisition during a bolus of contrast, followed by posthoc contrast agent leakage correction. Pseudocontinuous ASL was collected using 30 pairs of tag and control acquisition using a 3-dimensional gradient-echo spin-echo (GRASE) acquisition. All images were registered to a high-resolution anatomical atlas. Average CBF measurements within regions of contrast-enhancement and T2 hyperintensity were evaluated between the two modalities. Additionally, voxel-wise correlation between CBF measurements obtained with DSC and ASL were assessed. Results demonstrated a positive linear correlation between DSC and ASL measurements of CBF when regional average values were compared; however, a statistically significant voxel-wise correlation was only observed in around 30-40% of patients. These results suggest DSC and ASL may provide regionally similar, but spatially different measurements of CBF.

  3. Principal component analysis of the dynamic response measured by fMRI: a generalized linear systems framework.

    Science.gov (United States)

    Andersen, A H; Gash, D M; Avison, M J

    1999-07-01

    Principal component analysis (PCA) is one of several structure-seeking multivariate statistical techniques, exploratory as well as inferential, that have been proposed recently for the characterization and detection of activation in both PET and fMRI time series data. In particular, PCA is data driven and does not assume that the neural or hemodynamic response reaches some steady state, nor does it involve correlation with any pre-defined or exogenous experimental design template. In this paper, we present a generalized linear systems framework for PCA based on the singular value decomposition (SVD) model for representation of spatio-temporal fMRI data sets. Statistical inference procedures for PCA, including point and interval estimation will be introduced without the constraint of explicit hypotheses about specific task-dependent effects. The principal eigenvectors capture both the spatial and temporal aspects of fMRI data in a progressive fashion; they are inherently matched to unique and uncorrelated features and are ranked in order of the amount of variance explained. PCA also acts as a variation reduction technique, relegating most of the random noise to the trailing components while collecting systematic structure into the leading ones. Features summarizing variability may not directly be those that are the most useful. Further analysis is facilitated through linear subspace methods involving PC rotation and strategies of projection pursuit utilizing a reduced, lower-dimensional natural basis representation that retains most of the information. These properties will be illustrated in the setting of dynamic time-series response data from fMRI experiments involving pharmacological stimulation of the dopaminergic nigro-striatal system in primates.

  4. Accuracy of fully automated, quantitative, volumetric measurement of the amount of fibroglandular breast tissue using MRI: correlation with anthropomorphic breast phantoms.

    Science.gov (United States)

    Wengert, Georg J; Pinker, Katja; Helbich, Thomas H; Vogl, Wolf-Dieter; Spijker, Sylvia M; Bickel, Hubert; Polanec, Stephan H; Baltzer, Pascal A

    2017-06-01

    To demonstrate the accuracy of fully automated, quantitative, volumetric measurement of the amount of fibroglandular breast tissue (FGT), using MRI, and to investigate the impact of different MRI sequences using anthropomorphic breast phantoms as the ground truth. In this study, 10 anthropomorphic breast phantoms that consisted of different known fractions of adipose and protein tissue, which closely resembled normal breast parenchyma, were developed. Anthropomorphic breast phantoms were imaged with a 1.5 T unit (Siemens, Avantofit) using an 18-channel breast coil. The sequence protocol consisted of an isotropic Dixon sequence (Di), an anisotropic Dixon sequence (Da), and T1 3D FLASH sequences with and without fat saturation (T1). Fully automated, quantitative, volumetric measurement of FGT for all anthropomorphic phantoms and sequences was performed and correlated with the amounts of fatty and protein components in the phantoms as the ground truth. Fully automated, quantitative, volumetric measurements of FGT with MRI for all sequences ranged from 5.86 to 61.05% (mean 33.36%). The isotropic Dixon sequence yielded the highest accuracy (median 0.51%-0.78%) and precision (median range 0.19%) compared with anisotropic Dixon (median 1.92%-2.09%; median range 0.55%) and T1 -weighted sequences (median 2.54%-2.46%; median range 0.82%). All sequences yielded good correlation with the FGT content of the anthropomorphic phantoms. The best correlation of FGT measurements was identified for Dixon sequences (Di, R(2)  = 0.999; Da, R(2)  = 0.998) compared with conventional T1 -weighted sequences (R(2)  = 0.971). MRI yields accurate, fully automated, quantitative, volumetric measurements of FGT, an increasingly important and sensitive imaging biomarker for breast cancer risk. Compared with conventional T1 sequences, Dixon-type sequences show the highest correlation and reproducibility for automated, quantitative, volumetric FGT measurements using anthropomorphic breast

  5. Direct comparison of local cerebral blood flow rates measured by MRI arterial spin-tagging and quantitative autoradiography in a rat model of experimental cerebral ischemia.

    Science.gov (United States)

    Ewing, James R; Wei, Ling; Knight, Robert A; Pawa, Swati; Nagaraja, Tavarekere N; Brusca, Thomas; Divine, George W; Fenstermacher, Joseph D

    2003-02-01

    The present study determined cerebral blood flow (CBF) in the rat using two different magnetic resonance imaging (MRI) arterial spin-tagging (AST) methods and 14C-iodoantipyrine (IAP)-quantitative autoradiography (QAR), a standard but terminal technique used for imaging and quantitating CBF, and compared the resulting data sets to assess the precision and accuracy of the different techniques. Two hours after cerebral ischemia was produced in eight rats via permanent occlusion of one middle cerebral artery (MCA) with an intraluminal suture, MRI-CBF was measured over a 2.0-mm coronal slice using single-coil AST, and tissue magnetization was assessed by either a spin-echo (SE) or a variable tip-angle gradient-echo (VTA-GE) readout. Subsequently ( approximately 2.5 hours after MCA occlusion), CBF was assayed by QAR with the blood flow indicator 14C-IAP, which produced coronal images of local flow rates every 0.4 mm along the rostral-caudal axis. The IAP-QAR images that spanned the 2-mm MRI slice were selected, and regional flow rates (i.e., local CBF [lCBF]) were measured and averaged across this set of images by both the traditional approach, which involved reader interaction and avoidance of sectioning artifacts, and a whole film-scanning technique, which approximated total radioactivity in the entire MRI slice with minimal user bias. After alignment and coregistration, the concordance of the CBF rates generated by the two QAR approaches and the two AST methods was examined for nine regions of interest in each hemisphere. The QAR-lCBF rates were higher with the traditional method of assaying tissue radioactivity than with the MRI-analog approach; although the two sets of rates were highly correlated, the scatter was broad. The flow rates obtained with the whole film-scanning technique were chosen for subsequent comparisons to MRI-CBF results because of the similarity in tissue "sampling" among these three methods. As predicted by previous modeling, "true" flow rates

  6. Effects of spin-lock field direction on the quantitative measurement of spin-lattice relaxation time constant in the rotating frame (T1ρ) in a clinical MRI system

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Seonghwan, E-mail: Seonghwan.Yee@Beaumont.edu [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States); Gao, Jia-Hong [Center for MRI Research, Peking University, Beijing 100871 (China)

    2014-12-15

    Purpose: To investigate whether the direction of spin-lock field, either parallel or antiparallel to the rotating magnetization, has any effect on the spin-lock MRI signal and further on the quantitative measurement of T1ρ, in a clinical 3 T MRI system. Methods: The effects of inverted spin-lock field direction were investigated by acquiring a series of spin-lock MRI signals for an American College of Radiology MRI phantom, while the spin-lock field direction was switched between the parallel and antiparallel directions. The acquisition was performed for different spin-locking methods (i.e., for the single- and dual-field spin-locking methods) and for different levels of clinically feasible spin-lock field strength, ranging from 100 to 500 Hz, while the spin-lock duration was varied in the range from 0 to 100 ms. Results: When the spin-lock field was inverted into the antiparallel direction, the rate of MRI signal decay was altered and the T1ρ value, when compared to the value for the parallel field, was clearly different. Different degrees of such direction-dependency were observed for different spin-lock field strengths. In addition, the dependency was much smaller when the parallel and the antiparallel fields are mixed together in the dual-field method. Conclusions: The spin-lock field direction could impact the MRI signal and further the T1ρ measurement in a clinical MRI system.

  7. The use of the lumbosacral enlargement as an intrinsic imaging biomarker: feasibility of grey matter and white matter cross-sectional area measurements using MRI at 3T.

    Directory of Open Access Journals (Sweden)

    Marios C Yiannakas

    Full Text Available Histopathological studies have demonstrated the involvement of spinal cord grey matter (GM and white matter (WM in several diseases and recent research has suggested the use of magnetic resonance imaging (MRI as a promising tool for in vivo assessment of the upper spinal cord. However, many neurological conditions would benefit from quantitative assessment of tissue integrity at different levels and relatively little work has been done, mainly due to technical challenges associated with imaging the lower spinal cord. In this study, the value of the lumbosacral enlargement (LSE as an intrinsic imaging biomarker was determined by exploring the feasibility of obtaining within it reliable GM and WM cross-sectional area (CSA measurements by means of a commercially available MRI system at 3 tesla (T. 10 healthy volunteers (mean age 27.5 years, 6 female gave written informed consent and high resolution images of the LSE were acquired and analysed using an optimised MRI acquisition and analysis protocol. GM and WM mean CSA measurements were obtained from a 15 mm section at the level of the LSE and the reproducibility of the measurements was determined by means of scan-rescan, intra- and inter-observer assessments. Mean (±SD LSE cross-sectional area (LSE-CSA was 62.3 (±4.1 mm2 and mean (±SD LSE grey matter cross-sectional area (LSE-GM-CSA was 19.8 (±3.3 mm2. The mean scan-rescan, intra- and inter-observer % coefficient of variation (COV for measuring the LSE-CSA were 2%, 2% and 2.5%, respectively and for measuring the LSE-GM-CSA were 7.8%, 8% and 8.6%, respectively. This study has shown that the LSE can be used reliably as an intrinsic imaging biomarker. The method presented here can be potentially extended to study the LSE in the diseased state and could provide a solid foundation for subsequent multi-parametric MRI investigations.

  8. Distinguishing drought and water scarcity

    NARCIS (Netherlands)

    Loon, van A.

    2013-01-01

    Water resources can become strained by both natural factors such as drought and human factors such as unsustainable use. Water resource managers can develop practices to reduce overuse of water resources, but they cannot prevent droughts, so distinguishing the causes of water stress can be useful.

  9. Soft tissue artefacts of the human back: comparison of the sagittal curvature of the spine measured using skin markers and an open upright MRI.

    Directory of Open Access Journals (Sweden)

    Roland Zemp

    Full Text Available Soft tissue artefact affects the determination of skeletal kinematics. Thus, it is important to know the accuracy and limitations of kinematic parameters determined and modelled based on skin marker data. Here, the curvature angles, as well as the rotations of the lumbar and thoracic segments, of seven healthy subjects were determined in the sagittal plane using a skin marker set and compared to measurements taken in an open upright MRI scanner in order to understand the influence of soft tissue artefact at the back. The mean STA in the flexed compared to the extended positions were 10.2±6.1 mm (lumbar/9.3±4.2 mm (thoracic and 10.7±4.8 mm (lumbar/9.2±4.9 mm (thoracic respectively. A linear regression of the lumbar and thoracic curvatures between the marker-based measurements and MRI-based measurements resulted in coefficients of determination, R2, of 0.552 and 0.385 respectively. Skin marker measurements therefore allow for the assessment of changes in the lumbar and thoracic curvature angles, but the absolute values suffer from uncertainty. Nevertheless, this marker set appears to be suitable for quantifying lumbar and thoracic spinal changes between quasi-static whole body postural changes.

  10. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

    Science.gov (United States)

    Bonutti, F; Tecchio, M; Maieron, M; Trevisan, D; Negro, C; Calligaris, F

    2016-03-01

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures.

  11. [Abnormal cerebral blood flow distributions during the post-ictal phase of febrile status epilepticus in three pediatric patients measured by arterial spin labeling perfusion MRI].

    Science.gov (United States)

    Hirano, Keiko; Fukuda, Tokiko

    2016-05-01

    The ability to visualize brain perfusion is important for identifying epileptic foci. We present three pediatric cases showing asymmetrical cerebral blood flow (CBF) distributions during the post-ictal phase of febrile status epilepticus measured by arterial spin labeling (ASL) perfusion MRI. During the acute phase, regional CBF measurements in the areas considered including epileptic foci were higher than in the corresponding area of the contralateral hemisphere, though the exact quantitative value varied between cases. We could not identify the correct epileptogenic foci, because those ASL images were taken after the prolonged and extraordinary activation of neurons in the affected area. During the recovery phase, the differences reduced and the average regional CBF measurement was 54.6 ± 6.1 ml/100 g per minute, which was a little less than the number of previous ASL studies. ASL perfusion MRI imaging provides a method for evaluating regional CBF by using magnetically labeled arterial blood water as an endogenous tracer. With this technique, we can repeatedly evaluate both the brain structure and the level of perfusion at the same time. ASL is noninvasive and easily accessible, and therefore it could become a routine tool for assessment of perfusion in daily practice of pediatric neurology.

  12. MRI Artifacts

    Directory of Open Access Journals (Sweden)

    Abed Al Nasser Assi

    2009-12-01

    Full Text Available   "nMagnetic resonance imaging (MRI has become more and more frequently used in medical imaging diagnostic in recent years. Radiologists and technicians working at these systems are relatively often confronted with image artifacts related to the radiowave with strong magnetic in the scanner. Many artifacts may be corrected or modulated through an understanding of their cause. This requires familiarity with scanner design; theory of operation; and image acquisition. The purpose of this review article is to present the most relevant artifacts that arise in MRI scanner, to provide some physical background on the formation of artifacts, and to suggest strategies to reduce or avoid these artifacts. The most frequent artifacts that can occur during MRI scanning are Motion related artifacts; Para-magnetic artifacts; Phase Wrap artifacts; Frequency artifacts; Susceptibility artifacts; Clipping artefact; Chemical Shift artifact and "Zebra" artefact .    "n  

  13. Portable MRI

    Energy Technology Data Exchange (ETDEWEB)

    Espy, Michelle A. [Los Alamos National Laboratory

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  14. MRI in Optic Neuritis: Structure, Function, Interactions

    DEFF Research Database (Denmark)

    Fuglø, Dan

    2011-01-01

    resonance imaging (MRI), and the visual evoked potential (VEP) continues to show a delayed P100 indicating persistent demyelination. The explanation for this apparent discrepancy between structure and function could be due to either a redundancy in the visual pathways so that some degree of signal loss...... are low. Functional MRI (fMRI) is a non-invasive technique that can measure brain activity with a high spatial resolution. Recently, technical and methodological advancements have made it feasible to record VEPs and fMRI simultaneously and the relationship between averaged VEPs and averaged fMRI signals...... have been described. Still, to take full advantage of simultaneously recorded VEP-fMRI one would ideally want to track single-trial changes in the VEP and use this information in the fMRI analysis. In order to do this we examined 10 healthy volunteers with simultaneous VEP-fMRI. Different measures...

  15. An analysis of the uncertainty and bias in DCE-MRI measurements using the spoiled gradient-recalled echo pulse sequence

    Energy Technology Data Exchange (ETDEWEB)

    Subashi, Ergys [Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 and Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States); Choudhury, Kingshuk R. [Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27710 (United States); Johnson, G. Allan, E-mail: gjohnson@duke.edu [Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 (United States); Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2014-03-15

    Purpose: The pharmacokinetic parameters derived from dynamic contrast-enhanced (DCE) MRI have been used in more than 100 phase I trials and investigator led studies. A comparison of the absolute values of these quantities requires an estimation of their respective probability distribution function (PDF). The statistical variation of the DCE-MRI measurement is analyzed by considering the fundamental sources of error in the MR signal intensity acquired with the spoiled gradient-echo (SPGR) pulse sequence. Methods: The variance in the SPGR signal intensity arises from quadrature detection and excitation flip angle inconsistency. The noise power was measured in 11 phantoms of contrast agent concentration in the range [0–1] mM (in steps of 0.1 mM) and in onein vivo acquisition of a tumor-bearing mouse. The distribution of the flip angle was determined in a uniform 10 mM CuSO{sub 4} phantom using the spin echo double angle method. The PDF of a wide range of T1 values measured with the varying flip angle (VFA) technique was estimated through numerical simulations of the SPGR equation. The resultant uncertainty in contrast agent concentration was incorporated in the most common model of tracer exchange kinetics and the PDF of the derived pharmacokinetic parameters was studied numerically. Results: The VFA method is an unbiased technique for measuringT1 only in the absence of bias in excitation flip angle. The time-dependent concentration of the contrast agent measured in vivo is within the theoretically predicted uncertainty. The uncertainty in measuring K{sup trans} with SPGR pulse sequences is of the same order, but always higher than, the uncertainty in measuring the pre-injection longitudinal relaxation time (T1{sub 0}). The lowest achievable bias/uncertainty in estimating this parameter is approximately 20%–70% higher than the bias/uncertainty in the measurement of the pre-injection T1 map. The fractional volume parameters derived from the extended Tofts model

  16. Diagnostic value of chemical shift artifact in distinguishing benign lymphadenopathy

    Energy Technology Data Exchange (ETDEWEB)

    Farshchian, Nazanin, E-mail: farshchian.n@gmail.com [Department of Radiology, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Tamari, Saghar; Farshchian, Negin [Department of Radiology, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Madani, Hamid [Department of Pathology, Imam-Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Rezaie, Mansour [Department of Biostatistics, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Mohammadi-Motlagh, Hamid-Reza, E-mail: mohammadimotlagh@gmail.com [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

    2011-11-15

    Purpose: Today, distinguishing metastatic lymph nodes from secondary benign inflammatory ones via using non-invasive methods is increasingly favorable. In this study, the diagnostic value of chemical shift artifact (CSA) in magnetic resonance imaging (MRI) was evaluated to distinguish benign lymphadenopathy. Subjects and methods: A prospective intraindividual internal review board-approved study was carried out on 15 men and 15 women having lymphadenopathic lesions in different locations of the body who underwent contrast-enhanced dynamic MR imaging at 1.5 T. Then, the imaging findings were compared with pathology reports, using the statistics analyses. Results: Due to the findings of the CSA existence in MRI, a total of 56.7% of the studied lesions (17 of 30) were identified as benign lesions and the rest were malignant, whereas the pathology reports distinguished twelve malignant and eighteen benign cases. Furthermore, the CSA findings comparing the pathology reports indicated that CSA, with confidence of 79.5%, has a significant diagnostic value to differentiate benign lesions from malignant ones. Conclusion: Our study demonstrated that CSA in MR imaging has a suitable diagnostic potential nearing readiness for clinical trials. Furthermore, CSA seems to be a feasible tool to differentiate benign lymph nodes from malignant ones; however, further studies including larger numbers of patients are required to confirm our results.

  17. MRI-derived measurements of human subcortical, ventricular and intracranial brain volumes: Reliability effects of scan sessions, acquisition sequences, data analyses, scanner upgrade, scanner vendors and field strengths.

    Science.gov (United States)

    Jovicich, Jorge; Czanner, Silvester; Han, Xiao; Salat, David; van der Kouwe, Andre; Quinn, Brian; Pacheco, Jenni; Albert, Marilyn; Killiany, Ronald; Blacker, Deborah; Maguire, Paul; Rosas, Diana; Makris, Nikos; Gollub, Randy; Dale, Anders; Dickerson, Bradford C; Fischl, Bruce

    2009-05-15

    Automated MRI-derived measurements of in-vivo human brain volumes provide novel insights into normal and abnormal neuroanatomy, but little is known about measurement reliability. Here we assess the impact of image acquisition variables (scan session, MRI sequence, scanner upgrade, vendor and field strengths), FreeSurfer segmentation pre-processing variables (image averaging, B1 field inhomogeneity correction) and segmentation analysis variables (probabilistic atlas) on resultant image segmentation volumes from older (n=15, mean age 69.5) and younger (both n=5, mean ages 34 and 36.5) healthy subjects. The variability between hippocampal, thalamic, caudate, putamen, lateral ventricular and total intracranial volume measures across sessions on the same scanner on different days is less than 4.3% for the older group and less than 2.3% for the younger group. Within-scanner measurements are remarkably reliable across scan sessions, being minimally affected by averaging of multiple acquisitions, B1 correction, acquisition sequence (MPRAGE vs. multi-echo-FLASH), major scanner upgrades (Sonata-Avanto, Trio-TrioTIM), and segmentation atlas (MPRAGE or multi-echo-FLASH). Volume measurements across platforms (Siemens Sonata vs. GE Signa) and field strengths (1.5 T vs. 3 T) result in a volume difference bias but with a comparable variance as that measured within-scanner, implying that multi-site studies may not necessarily require a much larger sample to detect a specific effect. These results suggest that volumes derived from automated segmentation of T1-weighted structural images are reliable measures within the same scanner platform, even after upgrades; however, combining data across platform and across field-strength introduces a bias that should be considered in the design of multi-site studies, such as clinical drug trials. The results derived from the young groups (scanner upgrade effects and B1 inhomogeneity correction effects) should be considered as preliminary and in

  18. Breast MRI scan

    Science.gov (United States)

    MRI - breast; Magnetic resonance imaging - breast; Breast cancer - MRI; Breast cancer screening - MRI ... radiologist) see some areas more clearly. During the MRI, the person who operates the machine will watch ...

  19. MRI Safety during Pregnancy

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z MRI Safety During Pregnancy Magnetic resonance imaging (MRI) Illness ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor ...

  20. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  1. MRI of the Chest

    Medline Plus

    Full Text Available ... the limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) ... ray, CT and ultrasound. top of page How is the procedure performed? MRI examinations may be performed ...

  2. Quantum correlations and distinguishability of quantum states

    Science.gov (United States)

    Spehner, Dominique

    2014-07-01

    A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature.

  3. Measurement of blood-brain barrier permeability with t1-weighted dynamic contrast-enhanced MRI in brain tumors: a comparative study with two different algorithms.

    Science.gov (United States)

    Bergamino, Maurizio; Saitta, Laura; Barletta, Laura; Bonzano, Laura; Mancardi, Giovanni Luigi; Castellan, Lucio; Ravetti, Jean Louis; Roccatagliata, Luca

    2013-01-01

    The purpose of this study was to assess the feasibility of measuring different permeability parameters with T1-weighted dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in order to investigate the blood brain-barrier permeability associated with different brain tumors. The Patlak algorithm and the extended Tofts-Kety model were used to this aim. Twenty-five adult patients with tumors of different histological grades were enrolled in this study. MRI examinations were performed at 1.5 T. Multiflip angle, fast low-angle shot, and axial 3D T1-weighted images were acquired to calculate T1 maps, followed by a DCE acquisition. A region of interest was placed within the tumor of each patient to calculate the mean value of different permeability parameters. Differences in permeability measurements were found between different tumor grades, with higher histological grades characterized by higher permeability values. A significant difference in transfer constant (K (trans)) values was found between the two methods on high-grade tumors; however, both techniques revealed a significant correlation between the histological grade of tumors and their K (trans) values. Our results suggest that DCE acquisition is feasible in patients with brain tumors and that K (trans) maps can be easily obtained by these two algorithms, even if the theoretical model adopted could affect the final results.

  4. Improved cardiac MRI volume measurements in patients with tetralogy of Fallot by independent end-systolic and end-diastolic phase selection.

    Directory of Open Access Journals (Sweden)

    Hendrik G Freling

    Full Text Available OBJECTIVES: To investigate to what extent cardiac MRI derived measurements of right ventricular (RV volumes using the left ventricular (LV end-systolic and end-diastolic frame misrepresent RV end-systolic and end-diastolic volumes in patients with tetralogy of Fallot (ToF and a right bundle branch block. METHODS: Sixty-five cardiac MRI scans of patients with ToF and a right bundle branch block, and 50 cardiac MRI scans of control subjects were analyzed. RV volumes and function using the end-systolic and end-diastolic frame of the RV were compared to using the end-systolic and end-diastolic frame of the LV. RESULTS: Timing of the RV end-systolic frame was delayed compared to the LV end-systolic frame in 94% of patients with ToF and in 50% of control subjects. RV end-systolic volume using the RV end-systolic instead of LV end-systolic frame was smaller in ToF (median -3.3 ml/m(2, interquartile range -1.9 to -5.6 ml/m(2; p<0.001 and close to unchanged in control subjects. Using the RV instead of LV end-systolic and end-diastolic frame hardly affected RV end-diastolic volumes in both groups and ejection fraction in control subjects (54±4%, both methods, while increasing ejection fraction from 45±7% to 48±7% for patients with ToF (p<0.001. QRS duration correlated positively with the changes in the RV end-systolic volume (p<0.001 and RV ejection fraction obtained in ToF patients when using the RV instead of the LV end-systolic and end-diastolic frame (p = 0.004. CONCLUSION: For clinical decision making in ToF patients RV volumes derived from cardiac MRI should be measured in the end-systolic frame of the RV instead of the LV.

  5. MRI zoo

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard proced...

  6. Distinguishability and accessible information in quantum theory

    CERN Document Server

    Fuchs, C

    1996-01-01

    This document focuses on translating various information-theoretic measures of distinguishability for probability distributions into measures of distin- guishability for quantum states. These measures should have important appli- cations in quantum cryptography and quantum computation theory. The results reported include the following. An exact expression for the quantum fidelity between two mixed states is derived. The optimal measurement that gives rise to it is studied in detail. Several upper and lower bounds on the quantum mutual information are derived via similar techniques and compared to each other. Of note is a simple derivation of the important upper bound first proved by Holevo and an explicit expression for another (tighter) upper bound that appears implicitly in the same derivation. Several upper and lower bounds to the quan- tum Kullback relative information are derived. The measures developed are also applied to ferreting out the extent to which quantum systems must be disturbed by information...

  7. Serum neurofilament light chain in early relapsing remitting MS is increased and correlates with CSF levels and with MRI measures of disease severity.

    Science.gov (United States)

    Kuhle, Jens; Barro, Christian; Disanto, Giulio; Mathias, Amandine; Soneson, Charlotte; Bonnier, Guillaume; Yaldizli, Özguer; Regeniter, Axel; Derfuss, Tobias; Canales, Mathieu; Schluep, Myriam; Du Pasquier, Renaud; Krueger, Gunnar; Granziera, Cristina

    2016-10-01

    Neurofilament light chain (NfL) levels in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients correlate with the degree of neuronal injury. To date, little is known about NfL concentrations in the serum of relapsing remitting multiple sclerosis (RRMS) patients and their relationship with CSF levels and magnetic resonance imaging (MRI) measures of disease severity. We aimed to validate the quantification of NfL in serum samples of RRMS, as a biofluid source easily accessible for longitudinal studies. A total of 31 RRMS patients underwent CSF and serum sampling. After a median time of 3.6 years, 19 of these RRMS patients, 10 newly recruited RRMS patients and 18 healthy controls had a 3T MRI and serum sampling. NfL concentrations were determined by electrochemiluminescence immunoassay. NfL levels in serum were highly correlated to levels in CSF (r = 0.62, p = 0.0002). Concentrations in serum were higher in patients than in controls at baseline (p = 0.004) and follow-up (p = 0.0009) and did not change over time (p = 0.56). Serum NfL levels correlated with white matter (WM) lesion volume (r = 0.68, p NfL levels were highly correlated, and serum concentrations were increased in RRMS. Serum NfL levels correlated with MRI markers of WM disease severity. Our findings further support longitudinal studies of serum NfL as a potential biomarker of on-going disease progression and as a potential surrogate to quantify effects of neuroprotective drugs in clinical trials. © The Author(s), 2016.

  8. Cine phase-contrast MRI measurement of CSF flow in the cervical spine: a pilot study in patients with spinal cord injury

    Science.gov (United States)

    Negahdar, MJ; Shakeri, M.; McDowell, E.; Wells, J.; Vitaz, T.; Harkema, S.; Amini, A.

    2011-03-01

    MRI velocimetry (also known as phase-contrast MRI) is a powerful tool for quantification of cerebrospinal fluid (CSF) flow in various regions of the brain and craniospinal junction and has been accepted as a diagnostic tool to assist with the diagnosis of certain conditions such as hydrocephalus and chiari malformations. Cerebrospinal fluid is continually produced in the ventricles of the brain, flows through the ventricular system and then out and around the brain and spinal cord and is reabsorbed over the convexity of the brain. Any disease process which either impedes the normal pattern of flow or restricts the area where flow occurs can change the pattern of these waveforms with the direction and velocity of flow being determined by the pressure transmitted from the pulsation of the heart and circulation of blood within the central nervous system. Therefore, we hypothesized that phase-contrast MRI could eventually be used as a diagnostic aid in determining the degree of spinal cord compression following injury to the cervical or thoracic spine. In this study, we examined CSF flow in 3 normal subjects and 2 subjects with non-acute injuries in the cervical spine using Cine phasecontrast MRI. CSF flow analysis was performed using an in-house developed software. The flow waveform was calculated in both normal subjects (n=3) as well as subjects with spinal cord injury in the cervical spine (n=2). The bulk flow at C2 was measured to be 0.30 +/- 0.05 cc, at 5 cm distal to C2, it was 0.19+/- 0.07 cc, and at 10 cm distal to C2, it was 0.17+/- 0.05 cc. These results were in good agreement with previously published results. In patients with spinal cord injury, at the site of injury in the cervical spine, bulk flow was found to be 0.08 +/- 0.12 cc, at 5 cm proximal to the site of injury it was found to be 0.18 +/- 0.07 cc, and at 5 cm distal to the site of injury, it was found to be 0.12 +/- 0.01 cc.

  9. Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant in Cognitively Impaired Patients.

    Directory of Open Access Journals (Sweden)

    Eric R Braverman

    Full Text Available To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19-90 years displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54, 57.14% central atrophy (N=88, and 44.52% temporal atrophy (N=69. A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III scores differentially across various brain loci. Delayed latency (p=0.0740 was marginally associated with temporal atrophy; reduced fractional anisotropy (FA in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115. Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787. In the centrum semiovale (CS, reduced FA correlated with visual memory (p=0.0622. Lower demyelination correlated with higher P300 amplitude (p=0.0002. Compared to males, females have higher demyelination (p=0.0064. Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165. Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087. In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740; high auditory memory and low temporal atrophy (p=0.0417; and high working memory and low temporal atrophy (p=0.0166. Central atrophy correlated with aging and immediate memory (p=0.0294: the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost

  10. Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients

    Science.gov (United States)

    Braverman, Eric R.; Blum, Kenneth; Hussman, Karl L.; Han, David; Dushaj, Kristina; Li, Mona; Marin, Gabriela; Badgaiyan, Rajendra D.; Smayda, Richard; Gold, Mark S.

    2015-01-01

    To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19–90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost

  11. Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients.

    Science.gov (United States)

    Braverman, Eric R; Blum, Kenneth; Hussman, Karl L; Han, David; Dushaj, Kristina; Li, Mona; Marin, Gabriela; Badgaiyan, Rajendra D; Smayda, Richard; Gold, Mark S

    2015-01-01

    To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19-90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost

  12. Association of the Fractal Dimension of Retinal Arteries and Veins with Quantitative Brain MRI Measures in HIV-Infected and Uninfected Women.

    Directory of Open Access Journals (Sweden)

    Howard A Crystal

    Full Text Available The fractal dimension of retinal arteries and veins is a measure of the complexity of the vascular tree. We hypothesized that retinal fractal dimension would be associated with brain volume and white matter integrity in HIV-infected women.Nested case-control within longitudinal cohort study.Women were recruited from the Brooklyn site of the Women's Interagency HIV study (WIHS; 34 HIV-infected and 21 HIV-uninfected women with analyzable MRIs and retinal photographs were included. Fractal dimension was determined using the SIVA software program on skeletonized retinal images. The relationship between predictors (retinal vascular measures and outcomes (quantitative MRI measures were analyzed with linear regression models. All models included age, intracranial volume, and both arterial and venous fractal dimension. Some models were adjusted for blood pressure, race/ethnicity, and HIV-infection.The women were 45.6 ± 7.3 years of age. Higher arterial dimension was associated with larger cortical volumes, but higher venous dimension was associated with smaller cortical volumes. In fully adjusted models, venous dimension was significantly associated with fractional anisotropy (standardized β = -0.41, p = 0.009 and total gray matter volume (β = -0.24, p = 0.03, and arterial dimension with mean diffusivity (β = -0.33,.p = 0.04 and fractional anisotropy (β = 0.34, p = 0.03. HIV-infection was not associated with any retinal or MRI measure.Higher venous fractal dimension was associated with smaller cortical volumes and lower fractional anisotropy, whereas higher arterial fractal dimension was associated with the opposite patterns. Longitudinal studies are needed to validate this finding.

  13. Battlefield MRI

    Energy Technology Data Exchange (ETDEWEB)

    Espy, Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-01

    Magnetic Resonance Imaging is the best method for non-invasive imaging of soft tissue anatomy, saving countless lives each year. It is regarded as the gold standard for diagnosis of mild to moderate traumatic brain injuries. Furthermore, conventional MRI relies on very high, fixed strength magnetic fields (> 1.5 T) with parts-per-million homogeneity, which requires very large and expensive magnets.

  14. Distance between the rectal wall and mesorectal fascia measured by MRI: Effect of rectal distension and implications for preoperative prediction of a tumour-free circumferential resection margin

    Energy Technology Data Exchange (ETDEWEB)

    Slater, A. [Department of Specialist Radiology, University College Hospital, London (United Kingdom); Halligan, S. [Department of Specialist Radiology, University College Hospital, London (United Kingdom); Taylor, S.A. [Department of Specialist Radiology, University College Hospital, London (United Kingdom); Marshall, M. [Intestinal Imaging Centre, St Mark' s Hospital, Northwick Park, London (United Kingdom)

    2006-01-15

    Aim: To determine the effect of rectal distension, used by some workers to facilitate staging, on mesorectal tissues. Subjects and methods: Ninety-seven consecutive rectal cancer staging MRI examinations were identified of which 76 were analysable: 48 studies were performed using rectal insufflation of 100 ml room air and 28 were performed without distension. Median age was 69 and 72 years, respectively. In each patient a single experienced observer measured the distance from the outer rectal wall to the inner margin of the mesorectal fascia at four locations (12, 3, 6 and 9 o'clock), excluding sites of tumour involvement, from the T1-weighted axial image at the level of the sacro-coccygeal junction. The two groups of measurements were compared using Mann-Whitney test statistic, and frequencies then categorized into <5 mm or {>=}5 mm, and compared using Fisher's exact test. Results: The median distance between the rectal wall and mesorectal fascia in the distended group was approximately half that found in the non-distended group, and significantly lower at the 3, 6 and 9 o'clock positions (p<0.001). 68/167 (41%) of measurements were 5 mm or less, compared with 19/104 (18%) in the non-distended group (p<0.001). Conclusion: Rectal distension before MRI significantly reduces the distance between the rectal wall and mesorectal fascia. Although this is advocated to facilitate visualization of the primary tumour, it potentially affects the accuracy with which a clear circumferential resection margin can be predicted.

  15. MRI measurements of the pons and cerebellum in children born preterm; associations with the severity of periventricular leukomalacia and perinatal risk factors

    Energy Technology Data Exchange (ETDEWEB)

    Argyropoulou, M.I.; Xydis, V.; Argyropoulou, P.I.; Efremidis, S.C. [Department of Radiology, Medical School, University of Ioannina (Greece); Drougia, A.; Andronikou, S. [Neonatology Unit, Department of Paediatrics, Medical School, University of Ioannina (Greece); Tzoufi, M. [Department of Paediatrics, Medical School, University of Ioannina (Greece); Bassounas, A. [Department of Computer Science, Unit of Medical Technology and Intelligent Information Systems, University of Ioannina (Greece)

    2003-10-01

    Our purpose was to measure the size of the pons and cerebellum in preterm babies with periventricular leukomalacia (PVL), and to study their relationship with the severity of PVL and with perinatal risk factors. We examined 33 premature children, mean gestational age 31 weeks, range 26-36 weeks with PVL on MRI, and 27 full-term controls. On MRI at 0.4-5.5 years (mean 1.4 years) we measured the area of the corpus callosum and vermis, the anteroposterior diameter of the pons and the volume of the cerebellum. The area of the corpus callosum was used as a marker of white matter loss and PVL severity. All regional brain measurements except that of the vermis were significantly lower in patients than controls: corpus callosum (mm{sup 2}): 239.6{+-}92.5 vs 434.8{+-}126.8, P <0.01; pons (mm): 14.8{+-}3.0 vs 17.9{+-}1.4, P <0.01; cerebellum (cm{sup 3}): 68.2{+-}31.6 vs 100.6{+-}28.3, P <0.01; vermis (mm{sup 2}): 808.1{+-}292.2 vs 942.2{+-}246.2, NS. Significant reduction in the area of the vermis: 411.3{+-}203.3 vs 935{+-}252.6 mm{sup 2}; cerebellar volume: 16.3{+-}12.5 vs 96.6{+-}20.2 mm{sup 3}; and the diameter of the pons: 10.1{+-}2.2 vs 17.5{+-}1.3 mm (P <0.01) were observed in seven children with gestational age {<=}28 weeks, severe hypotension and large patent ductus arteriosus (PDA). There was a significant correlation between the duration of mechanical ventilation and the size of the vermis, pons and cerebellum (R=-0.65, -0.57 and -0.73, respectively, P <0.01). (orig.)

  16. A longitudinal observational study of brain atrophy rate reflecting four decades of multiple sclerosis: a comparison of serial 1D, 2D, and volumetric measurements from MRI images

    Energy Technology Data Exchange (ETDEWEB)

    Martola, Juha; Zhang, Yi; Aspelin, Peter; Kristoffersen Wiberg, Maria [Karolinska Institutet, Division of Radiology, Department of Clinical Science, Intervention, and Technology, Stockholm (Sweden); Bergstroem, Jakob [Karolinska Institutet, The Medical Statistics Unit, Department of Learning, Informatics, Management and Ethics (LIME), Stockholm (Sweden); Fredrikson, Sten; Stawiarz, Leszek; Hillert, Jan [Karolinska Institutet, Division of Neurology, Department of Clinical Neuroscience, Stockholm (Sweden); Flodmark, Olof; Lilja, Anders [Karolinska University Hospital, Department of Neuroradiology, Department of Clinical Neuroscience, Stockholm (Sweden); Ekbom, Anders [Karolinska Institutet, Clinical Epidemiology Unit, Stockholm (Sweden)

    2010-02-15

    Multiple sclerosis (MS) has a variable progression with an early onset of atrophy. Individual longitudinal radiological evaluations (over decades) are difficult to perform due to the limited availability of magnetic resonance imaging (MRI) in the past, patients lost in follow-up, and the continuous updating of scanners. We studied a cohort with widespread disease duration at baseline. The observed individual atrophy rates over time of 10 years represented four decades of disease span. Thirty-seven MS patients (age range 24-65 years with disease duration 1-33 years) were consecutively selected and evaluated with MRI at baseline 1995 and in 1996. They were followed up for a decade (mean of 9.25 years, range 7.3-10 years) up to 2003-2005. Brain parenchymal volume and volumes of the supratentorial ventricles were analyzed with semi-automated volumetric measurements at three time points (1995, 1996, and 2003-2005). Volumetric differences were found over shorter periods of time (1-7 months); however, differences vanished by the end of follow-up. A uniform longitudinal decrease in brain volume and increase in ventricle volumes were found. Frontal horn width (1D) correlated strongest to 3D measures. No statistical differences of atrophy rates between MS courses were found. Supratentorial ventricular volumes were associated with disability and this association persisted during follow-up. Despite variable clinical courses, the degenerative effects of MS progression expressed in brain atrophy seem to uniformly progress over longer periods of time. These volumetric changes can be detected using 1D and 2D measurements performed on a routine PACS workstation. (orig.)

  17. A new diagnostic score to detect osteoporosis in patients undergoing lumbar spine MRI

    Energy Technology Data Exchange (ETDEWEB)

    Bandirali, Michele; Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Di Leo, Giovanni; Papini, Giacomo Davide Edoardo [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Sconfienza, Luca Maria; Sardanelli, Francesco [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy); Ulivieri, Fabio Massimo [IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Servizio di Medicina Nucleare, Milano (Italy)

    2015-10-15

    Signal intensity of lumbar-spine at magnetic resonance imaging (MRI) correlates to bone mineral density (BMD). Our aim was to define a quantitative MRI-based score to detect osteoporosis on lumbar-spine MRI. After Ethics Committee approval, we selected female patients who underwent both lumbar-spine MRI and dual-energy X-ray absorptiometry (DXA) and a reference group of 131 healthy females (20-29 years) who underwent lumbar-spine MRI. We measured the intra-vertebral signal-to-noise ratio in L1-L4. We introduced an MRI-based score (M-score), on the model of T-score. M-score diagnostic performance in diagnosing osteoporosis was estimated against DXA using receiver operator characteristic (ROC) analysis. We included 226 patients (median age 65 years), 70 (31 %) being osteoporotic at DXA. MRI signal-to-noise ratio correlated to BMD (r = -0.677, P < 0.001). M-score negatively correlated to T-score (r = -0.682, P < 0.001). Setting a 90 %-specificity, an M-score threshold of 5.5 was found, distinguishing osteoporosis from non-osteoporosis (sensitivity 54 %; ROC AUC 0.844). Thirty-one (14 %) patients had a fragility fracture, with osteoporosis detected in 15 (48 %) according to M-score and eight (26 %) according to T-score (P = 0.016). M-score obtained on lumbar spine MRI is a quantitative method correlating with osteoporosis. Its diagnostic value remains to be demonstrated on a large prospective cohort of patients. (orig.)

  18. Measurement of human advanced brain function in calculation processing using functional magnetic resonance imaging (fMRI)

    Energy Technology Data Exchange (ETDEWEB)

    Hashida, Masahiro; Yamauchi, Syuichi [Yamaguchi Univ., Ube (Japan). Hospital; Wu, Jing-Long (and others)

    2001-06-01

    Using functional magnetic resonance imaging (fMRI), we investigated the activated areas of the human brain related with calculation processing as an advanced function of the human brain. Furthermore, we investigated differences in activation between visual and auditory calculation processing. The eight subjects (all healthy men) were examined on a clinical MR unit (1.5 tesla) with a gradient echo-type EPI sequence. SPM99 software was used for data processing. Arithmetic problems were used for the visual stimulus (visual image) as well as for the auditory stimulus (audible voice). The stimuli were presented to the subjects as follows: no stimulation, presentation of random figures, and presentation of arithmetic problems. Activated areas of the human brain related with calculation processing were the inferior parietal lobule, middle frontal gyrus, and inferior frontal gyrus. Comparing the arithmetic problems with the presentation of random figures, we found that the activated areas of the human brain were not differently affected by visual and auditory systems. The areas activated in the visual and auditory experiments were observed at nearly the same place in the brain. It is possible to study advanced functions of the human brain such as calculation processing in a general clinical hospital when adequate tasks and methods of presentation are used. (author)

  19. Fetal lung apparent diffusion coefficient measurement using diffusion-weighted MRI at 3 Tesla: Correlation with gestational age.

    Science.gov (United States)

    Afacan, Onur; Gholipour, Ali; Mulkern, Robert V; Barnewolt, Carol E; Estroff, Judy A; Connolly, Susan A; Parad, Richard B; Bairdain, Sigrid; Warfield, Simon K

    2016-12-01

    To evaluate the feasibility of using diffusion-weighted magnetic resonance imaging (DW-MRI) to assess the fetal lung apparent diffusion coefficient (ADC) at 3 Tesla (T). Seventy-one pregnant women (32 second trimester, 39 third trimester) were scanned with a twice-refocused Echo-planar diffusion-weighted imaging sequence with 6 different b-values in 3 orthogonal diffusion orientations at 3T. After each scan, a region-of-interest (ROI) mask was drawn to select a region in the fetal lung and an automated robust maximum likelihood estimation algorithm was used to compute the ADC parameter. The amount of motion in each scan was visually rated. When scans with unacceptable levels of motion were eliminated, the lung ADC values showed a strong association with gestational age (P < 0.01), increasing dramatically between 16 and 27 weeks and then achieving a plateau around 27 weeks. We show that to get reliable estimates of ADC values of fetal lungs, a multiple b-value acquisition, where motion is either corrected or considered, can be performed. J. Magn. Reson. Imaging 2016;44:1650-1655. © 2016 International Society for Magnetic Resonance in Medicine.

  20. Effects of b-value and number of gradient directions on diffusion MRI measures obtained with Q-ball imaging

    Science.gov (United States)

    Schilling, Kurt G.; Nath, Vishwesh; Blaber, Justin; Harrigan, Robert L.; Ding, Zhaohua; Anderson, Adam W.; Landman, Bennett A.

    2017-02-01

    High-angular-resolution diffusion-weighted imaging (HARDI) MRI acquisitions have become common for use with higher order models of diffusion. Despite successes in resolving complex fiber configurations and probing microstructural properties of brain tissue, there is no common consensus on the optimal b-value and number of diffusion directions to use for these HARDI methods. While this question has been addressed by analysis of the diffusion-weighted signal directly, it is unclear how this translates to the information and metrics derived from the HARDI models themselves. Using a high angular resolution data set acquired at a range of b-values, and repeated 11 times on a single subject, we study how the b-value and number of diffusion directions impacts the reproducibility and precision of metrics derived from Q-ball imaging, a popular HARDI technique. We find that Q-ball metrics associated with tissue microstructure and white matter fiber orientation are sensitive to both the number of diffusion directions and the spherical harmonic representation of the Q-ball, and often are biased when under sampled. These results can advise researchers on appropriate acquisition and processing schemes, particularly when it comes to optimizing the number of diffusion directions needed for metrics derived from Q-ball imaging.

  1. Distinguishing ichthyoses by protein profiling.

    Directory of Open Access Journals (Sweden)

    Robert H Rice

    Full Text Available To explore the usefulness of protein profiling for characterization of ichthyoses, we here determined the profile of human epidermal stratum corneum by shotgun proteomics. Samples were analyzed after collection on tape circles from six anatomic sites (forearm, palm, lower leg, forehead, abdomen, upper back, demonstrating site-specific differences in profiles. Additional samples were collected from the forearms of subjects with ichthyosis vulgaris (filaggrin (FLG deficiency, recessive X-linked ichthyosis (steroid sulfatase (STS deficiency and autosomal recessive congenital ichthyosis type lamellar ichthyosis (transglutaminase 1 (TGM1 deficiency. The ichthyosis protein expression patterns were readily distinguishable from each other and from phenotypically normal epidermis. In general, the degree of departure from normal was lower from ichthyosis vulgaris than from lamellar ichthyosis, parallel to the severity of the phenotype. Analysis of samples from families with ichthyosis vulgaris and concomitant modifying gene mutations (STS deficiency, GJB2 deficiency permitted correlation of alterations in protein profile with more complex genetic constellations.

  2. Distinguishing ichthyoses by protein profiling.

    Science.gov (United States)

    Rice, Robert H; Bradshaw, Katie M; Durbin-Johnson, Blythe P; Rocke, David M; Eigenheer, Richard A; Phinney, Brett S; Schmuth, Matthias; Gruber, Robert

    2013-01-01

    To explore the usefulness of protein profiling for characterization of ichthyoses, we here determined the profile of human epidermal stratum corneum by shotgun proteomics. Samples were analyzed after collection on tape circles from six anatomic sites (forearm, palm, lower leg, forehead, abdomen, upper back), demonstrating site-specific differences in profiles. Additional samples were collected from the forearms of subjects with ichthyosis vulgaris (filaggrin (FLG) deficiency), recessive X-linked ichthyosis (steroid sulfatase (STS) deficiency) and autosomal recessive congenital ichthyosis type lamellar ichthyosis (transglutaminase 1 (TGM1) deficiency). The ichthyosis protein expression patterns were readily distinguishable from each other and from phenotypically normal epidermis. In general, the degree of departure from normal was lower from ichthyosis vulgaris than from lamellar ichthyosis, parallel to the severity of the phenotype. Analysis of samples from families with ichthyosis vulgaris and concomitant modifying gene mutations (STS deficiency, GJB2 deficiency) permitted correlation of alterations in protein profile with more complex genetic constellations.

  3. Index Measurement for 0.5T Permanent Magnet MRI System%0.5T永磁MRI系统参数测量

    Institute of Scientific and Technical Information of China (English)

    尤剑颖; 包尚联

    2011-01-01

    Objective: To set up a set of index for our own developed 0.5T C type permanent magnet MRI system as the progress evaluation and reception check, which has been compared with national standard and gave the own self evaluation.Materials and Methods: Synthesizing the national standard and referencing the international standards of AAPM and NEMA,we proposed a set of index to be the manufacturer's standard for our 0.5T C type permanent MRI system,which included the uniformity, signal to noise of the image, geometry deformation, slice thickness and its uncertainty, space resolution et al.Conclusions: The index measured can token as its performance of the 0.5T C type permanent MRI system.The measurement results showed that the index, such as the space resolution has not seen reported inside of China.%目的:建立一套测量方法检测本课题组完成的0.5T C型永磁型磁共振成像系统的研究进展检测并对成果验收,并将检测结果与相关国家医药行业标准中对质量参数所提示的要求进行比较,并做出评价.材料与方法:采用体模,综合考虑AAPM及HEMA国际组织的测量标准,以及国家医药行业标准,提出一套方法用于测量本组内0.5T磁共振产品的测量参数集作为我们的企业标准,包括图像均匀性、图像信噪比、几何畸变、层厚及误差、空间分辨率等.结论:经过分析和比较,我们建立的测试参数系统能够表征0.5T永磁型磁共振系统的性能,我们研发的系统达到的技术指标,例如空间分辨率等指标在国内未见报道.

  4. The Compression Flow as a Measure to Estimate the Cognitive Impairment Severity in Resting State fMRI and 18FDG-PET Alzheimer's Disease Connectomes

    Directory of Open Access Journals (Sweden)

    Antonio Giuliano Zippo

    2015-12-01

    Full Text Available The human brain appears organized in compartments characterized by seemingly specific functional purposes on many spatial scales. A complementary functional state binds information from specialized districts to return what is called integrated information. This fundamental network dynamics undergoes to severe disarrays in diverse degenerative conditions such as Alzheimer's Diseases (AD. The AD represents a multifarious syndrome characterized by structural, functional and metabolic landmarks. In particular, in the early stages of AD, adaptive functional modifications of the brain networks mislead initial diagnoses because cognitive abilities may result indiscernible from normal subjects. As a matter of facts, current measures of functional integration fail to catch significant differences among normal, mild cognitive impairment (MCI and even AD subjects. The aim of this work is to introduce a new topological feature called Compression Flow (CF to finely estimate the extent of the functional integration in the brain networks. The method uses a Monte Carlo-like estimation of the information integration flows returning the compression ratio between the size of the injected information and the size of the condensed information within the network. We analyzed the resting state connectomes of 75 subjects of the Alzheimer's Disease Neuroimaging Initiative 2 (ADNI repository. Our analyses are focused on the 18FGD-PET and functional MRI (fMRI acquisitions in several clinical screening conditions. Results indicated that CF effectively discriminate MCI, AD and normal subjects by showing a significant decrease of the functional integration in the AD and MCI brain connectomes. This result did not emerge by using a set of common complex network statistics. Furthermore, CF was best correlated with individual clinical scoring scales. In conclusion, we presented a novel measure to quantify the functional integration that resulted efficient to discriminate

  5. MRI of the Chest

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of the chest ... limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is ...

  6. Response competition and response inhibition during different choice-discrimination tasks: evidence from ERP measured inside MRI scanner.

    Science.gov (United States)

    Gonzalez-Rosa, Javier J; Inuggi, Alberto; Blasi, Valeria; Cursi, Marco; Annovazzi, Pietro; Comi, Giancarlo; Falini, Andrea; Leocani, Letizia

    2013-07-01

    We investigated the neural correlates underlying response inhibition and conflict detection processes using ERPs and source localization analyses simultaneously acquired during fMRI scanning. ERPs were elicited by a simple reaction time task (SRT), a Go/NoGo task, and a Stroop-like task (CST). The cognitive conflict was thus manipulated in order to probe the degree to which information processing is shared across cognitive systems. We proposed to dissociate inhibition and interference conflict effects on brain activity by using identical Stroop-like congruent/incongruent stimuli in all three task contexts and while varying the response required. NoGo-incongruent trials showed a larger N2 and enhanced activations of rostral anterior cingulate cortex (ACC) and pre-supplementary motor area, whereas Go-congruent trials showed a larger P3 and increased parietal activations. Congruent and incongruent conditions of the CST task also elicited similar N2, P3 and late negativity (LN) ERPs, though CST-incongruent trials revealed a larger LN and enhanced prefrontal and ACC activations. Considering the stimulus probability and experimental manipulation of our study, current findings suggest that NoGo N2 and frontal NoGo P3 appear to be more associated to response inhibition rather than a specific conflict monitoring, whereas occipito-parietal P3 of Go and CST conditions may be more linked to a planned response competition between the prepared and required response. LN, however, appears to be related to higher level conflict monitoring associated with response choice-discrimination but not when the presence of cognitive conflict is associated with response inhibition.

  7. Measuring hepatic functional reserve using low temporal resolution Gd-EOB-DTPA dynamic contrast-enhanced MRI: a preliminary study comparing galactosyl human serum albumin scintigraphy with indocyanine green retention

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kazuhiro; Hashimoto, Tsuyoshi; Araki, Yoichi; Akata, Soichi; Tokuuye, Koichi [Tokyo Medical University, Department of Radiology, Tokyo (Japan); Ledsam, Joseph; Sourbron, Steven [University of Leeds, Division of Medical Physics, Leeds (United Kingdom)

    2014-01-15

    To investigate if tracer kinetic modelling of low temporal resolution dynamic contrast-enhanced (DCE) MRI with Gd-EOB-DTPA could replace technetium-99 m galactosyl human serum albumin (GSA) single positron emission computed tomography (SPECT) and indocyanine green (ICG) retention for the measurement of liver functional reserve. Twenty eight patients awaiting liver resection for various cancers were included in this retrospective study that was approved by the institutional review board. The Gd-EOB-DTPA MRI sequence acquired five images: unenhanced, double arterial phase, portal phase, and 4 min after injection. Intracellular contrast uptake rate (UR) and extracellular volume (Ve) were calculated from DCE-MRI, along with the ratio of GSA radioactivity of liver to heart-plus-liver and per cent of cumulative uptake from 15-16 min (LHL15 and LU15, respectively) from GSA-scintigraphy. ICG retention at 15 min, Child-Pugh cirrhosis score (CPS) and postoperative Inuyama fibrosis criteria were also recorded. Statistical analysis was with Spearman rank correlation analysis. Comparing MRI parameters with the reference methods, significant correlations were obtained for UR and LHL15, LU15, ICG15 (all 0.4-0.6, P < 0.05); UR and CPS (-0.64, P < 0.001); Ve and Inuyama (0.44, P < 0.05). Measures of liver function obtained by routine Gd-EOB-DTPA DCE-MRI with tracer kinetic modelling may provide a suitable method for the evaluation of liver functional reserve. (orig.)

  8. Reproducibility of Intra- and Inter-scanner Measurements of Liver Fat Using Complex Confounder-corrected Chemical Shift Encoded MRI at 3.0 Tesla

    Science.gov (United States)

    Wu, Bing; Han, Wei; Li, Zhenhong; Zhao, Yonghua; Ge, Mingmei; Guo, Xueqing; Wu, Xinhuai

    2016-01-01

    The purpose of this study was to prospectively evaluate the reproducibility of the proton density fat-fraction (PDFF) of the liver using the IDEAL algorithm, a quantitative confounder-corrected chemical-shift-encoded MRI method. Data were obtained from 15 volunteers on four different days. The first and the third examinations were conducted on scanner one with one-week intervals, while the second and the fourth tests were performed on scanner two with same time interval. For each test, two MR scans were performed, one before and one after a meal. Regions-of-interest measurements were manually calculated to estimate the PDFF in the right and left lobes on the PDFF images. Reproducibility was measured using the intra-class correlation coefficient (ICC). The ICCs of the PDFF in the right and left lobes were 0.935 and 0.878, respectively. The intra-scanner ICCs of the right lobe before and after a meal or at a one-week interval were 0.924 and 0.953, respectively. The inter-scanner ICCs of PDFF the next day and at a one-week interval were 0.920 and 0.864, respectively. The PDFF of liver derived from IDEAL demonstrated high intra- and inter-scanner measurement reproducibility. The PDFF of the right lobe before a meal was more reproducible than after-meal measurements. PMID:26763303

  9. Genetic correlates of brain aging on MRI and cognitive test measures: a genome-wide association and linkage analysis in the Framingham study

    Science.gov (United States)

    Seshadri, Sudha; DeStefano, Anita L; Au, Rhoda; Massaro, Joseph M; Beiser, Alexa S; Kelly-Hayes, Margaret; Kase, Carlos S; D'Agostino, Ralph B; DeCarli, Charles; Atwood, Larry D; Wolf, Philip A

    2007-01-01

    Background Brain magnetic resonance imaging (MRI) and cognitive tests can identify heritable endophenotypes associated with an increased risk of developing stroke, dementia and Alzheimer's disease (AD). We conducted a genome-wide association (GWA) and linkage analysis exploring the genetic basis of these endophenotypes in a community-based sample. Methods A total of 705 stroke- and dementia-free Framingham participants (age 62 +9 yrs, 50% male) who underwent volumetric brain MRI and cognitive testing (1999–2002) were genotyped. We used linear models adjusting for first degree relationships via generalized estimating equations (GEE) and family based association tests (FBAT) in additive models to relate qualifying single nucleotide polymorphisms (SNPs, 70,987 autosomal on Affymetrix 100K Human Gene Chip with minor allele frequency ≥ 0.10, genotypic call rate ≥ 0.80, and Hardy-Weinberg equilibrium p-value ≥ 0.001) to multivariable-adjusted residuals of 9 MRI measures including total cerebral brain (TCBV), lobar, ventricular and white matter hyperintensity (WMH) volumes, and 6 cognitive factors/tests assessing verbal and visuospatial memory, visual scanning and motor speed, reading, abstract reasoning and naming. We determined multipoint identity-by-descent utilizing 10,592 informative SNPs and 613 short tandem repeats and used variance component analyses to compute LOD scores. Results The strongest gene-phenotype association in FBAT analyses was between SORL1 (rs1131497; p = 3.2 × 10-6) and abstract reasoning, and in GEE analyses between CDH4 (rs1970546; p = 3.7 × 10-8) and TCBV. SORL1 plays a role in amyloid precursor protein processing and has been associated with the risk of AD. Among the 50 strongest associations (25 each by GEE and FBAT) were other biologically interesting genes. Polymorphisms within 28 of 163 candidate genes for stroke, AD and memory impairment were associated with the endophenotypes studied at p < 0.001. We confirmed our previously

  10. Edna B. Foa: Award for Distinguished Scientific Contributions.

    Science.gov (United States)

    2015-11-01

    The APA Awards for Distinguished Scientific Contributions are presented to persons who, in the opinion of the Committee on Scientific Awards, have made distinguished theoretical or empirical contributions to basic research in psychology. One of the 2015 award winners is Edna B. Foa, who received this award for "her outstanding and innovative research on the nature, measurement, and treatment of anxiety." Foa's award citation, biography, and a selected bibliography are presented here.

  11. MRI findings in meningeal cysts of the vertebral column

    Energy Technology Data Exchange (ETDEWEB)

    Chalkias, S.M. [Dept. of Radiology, AHEPA General Hospital of the Aristotelian Univ., Thessaloniki (Greece); Cova, M.A. [Dept. of Radiology, University Hospital of Trieste, Ospedale di Cattinara (Italy); Ricci, C. [Dept. of Radiology, University Hospital of Trieste, Ospedale di Cattinara (Italy); Magnaldi, S. [Dept. of Radiology, University Hospital of Trieste, Ospedale di Cattinara (Italy); Pozzi-Mucelli, R.S. [Dept. of Radiology, University Hospital of Trieste, Ospedale di Cattinara (Italy)

    1993-10-01

    The aim of this study was to demonstrate the MRI findings and to emphasise the contribution of MRI to the diagnosis of this rare pathology. MRI findings were evaluated according to a new classification that divides MCs into extradural cysts without (type 1) or with (type 2) spinal nerve root fibres and intradural cysts (type 3). Because of its high contrast resolution MRI can distinguish the three types of MC. The use of the different levels of signal intensity of the cyst and CSF in T2-weighted images to distinguish communicating from non-communicating MCs is illustrated. This diagnostic sign exploitats the signal loss due to flow phenomena of CSF pulsations on ungated sequences to reveal the communication of the MC with the SAS. We recommend MRI as the most sensitive and specific modality for the study of MCs. (orig.)

  12. Distinguishability of complete and unextendible product bases

    CERN Document Server

    De Rinaldis, S

    2003-01-01

    It is not always possible to distinguish multipartite orthogonal states if only local operation and classical communication (LOCC) are allowed. We prove that we cannot distinguish the states of an unextendible product bases (UPB) by LOCC even when infinite resources (infinite-dimensional ancillas, infinite number of operations). Moreover we give a method to check the LOCC distinguishability of a complete product bases.

  13. MRI assessment of relapsed glioblastoma during treatment with bevacizumab: Volumetric measurement of enhanced and FLAIR lesions for evaluation of response and progression—A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Pichler, Josef, E-mail: josef.pichler@gespag.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria); Pachinger, Corinna, E-mail: pachingercorinna@gmx.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria); Pelz, Manuela, E-mail: mauela.pelz@gespag.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria); Kleiser, Raimund, E-mail: raimund.kleiser@gespag.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria)

    2013-05-15

    Purpose: To develop a magnetic resonance imaging (MRI) metric that is useful for therapy monitoring in patients with relapsed glioblastoma (GBM) during treatment with the antiangiogenic monoclonal antibody bevacizumab (Bev). We evaluated the feasibility of tumour volume measurement with our software tool in clinical routine and tried to establish reproducible and quantitative parameters for surveillance of patients on treatment with antiangiogenic drugs. Materials and methods: In this retrospective institutional pilot study, 18 patients (11 men, 7 women; mean age 53.5) with recurrent GBM received bevacizumab and irinotecan every two weeks as second line therapy. Follow up scans were assessed every two to four months. Data were collected on a 1.5 T MR System (Siemens, Symphony) with the standard head coil using our standardized tumour protocol. Volumetric measurement was performed with a commercial available software stroketool in FLAIR and T1-c imaging with following procedure: Pre-processing involved cutting noise and electing a Gaussian of 3 × 3 to smooth images, selecting a ROI (region of interest) in healthy brain area of the contra lateral side with quantifying the intensity value, adding 20% to this value to define the threshold level. Only values above this threshold are left corresponding to the tumour lesion. For the volumetric measurement the detected tumour area was circuited in all slices and finally summing up all values and multiplied by slice thickness to get the whole volume. Results: With McDonalds criteria progression was indicated in 14 out of 18 patients. In contrast, volumetric measurement showed an increase of contrast enhancement of >25%, defined as threshold for progression, in 11 patients (78%) and in 12 patients (85%) in FLAIR volume, respectively. 6 patients revealed that volumes in MRI increased earlier than the last scan, which was primarily defined as the date of progression with McDonald criteria, changing PFS after re-evaluation of

  14. fMRI adaptation revisited.

    Science.gov (United States)

    Larsson, Jonas; Solomon, Samuel G; Kohn, Adam

    2016-07-01

    Adaptation has been widely used in functional magnetic imaging (fMRI) studies to infer neuronal response properties in human cortex. fMRI adaptation has been criticized because of the complex relationship between fMRI adaptation effects and the multiple neuronal effects that could underlie them. Many of the longstanding concerns about fMRI adaptation have received empirical support from neurophysiological studies over the last decade. We review these studies here, and also consider neuroimaging studies that have investigated how fMRI adaptation effects are influenced by high-level perceptual processes. The results of these studies further emphasize the need to interpret fMRI adaptation results with caution, but they also provide helpful guidance for more accurate interpretation and better experimental design. In addition, we argue that rather than being used as a proxy for measurements of neuronal stimulus selectivity, fMRI adaptation may be most useful for studying population-level adaptation effects across cortical processing hierarchies.

  15. Knee MRI scan

    Science.gov (United States)

    MRI - knee ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ... less anxious. Your provider may suggest an "open" MRI, in which the machine is not as close ...

  16. MRI of the Chest

    Medline Plus

    Full Text Available ... MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the chest is performed ...

  17. Play the MRI Game

    Science.gov (United States)

    ... Teachers' Questionnaire MRI Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  18. MRI of the Chest

    Medline Plus

    Full Text Available ... MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the chest is performed ...

  19. MRI of the Chest

    Medline Plus

    Full Text Available ... You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, ... Magnetic Resonance Imaging (MRI) Safety MRI Safety During Pregnancy Images related to Magnetic Resonance Imaging (MRI) - Chest ...

  20. Accuracy of distinguishing between dysembryoplastic neuroepithelial tumors and other epileptogenic brain neoplasms with [¹¹C]methionine PET.

    Science.gov (United States)

    Rheims, Sylvain; Rubi, Sebastià; Bouvard, Sandrine; Bernard, Emilien; Streichenberger, Nathalie; Guenot, Marc; Le Bars, Didier; Hammers, Alexander; Ryvlin, Philippe

    2014-10-01

    Dysembryoplastic neuroepithelial tumors (DNTs) represent a prevalent cause of epileptogenic brain tumors, the natural evolution of which is much more benign than that of most gliomas. Previous studies have suggested that [(11)C]methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumors, and hence optimize the management of patients. Here, we reassessed the diagnostic accuracy of MET-PET for the differentiation between DNT and other epileptogenic brain neoplasms in a larger population. We conducted a retrospective study of 77 patients with focal epilepsy related to a nonrapidly progressing brain tumor on MRI who underwent MET-PET, including 52 with a definite histopathology. MET-PET data were assessed by a structured visual analysis that distinguished normal, moderately abnormal, and markedly abnormal tumor methionine uptake and by semiquantitative ratio measurements. Pathology showed 21 DNTs (40%), 10 gangliogliomas (19%), 19 low-grade gliomas (37%), and 2 high-grade gliomas (4%). MET-PET visual findings significantly differed among the various tumor types (P < .001), as confirmed by semiquantitative analyses (P < .001 for all calculated ratios), regardless of gadolinium enhancement on MRI. All gliomas and gangliogliomas were associated with moderately or markedly increased tumor methionine uptake, whereas 9/21 DNTs had normal methionine uptake. Receiver operating characteristics analysis of the semiquantitative ratios showed an optimal cutoff threshold that distinguished DNTs from other tumor types with 90% specificity and 89% sensitivity. Normal MET-PET findings in patients with an epileptogenic nonrapidly progressing brain tumor are highly suggestive of DNT, whereas a markedly increased tumor methionine uptake makes this diagnosis unlikely. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e

  1. Accuracy of distinguishing between dysembryoplastic neuroepithelial tumors and other epileptogenic brain neoplasms with [11C]methionine PET

    Science.gov (United States)

    Rheims, Sylvain; Rubi, Sebastià; Bouvard, Sandrine; Bernard, Emilien; Streichenberger, Nathalie; Guenot, Marc; Le Bars, Didier; Hammers, Alexander; Ryvlin, Philippe

    2014-01-01

    Background Dysembryoplastic neuroepithelial tumors (DNTs) represent a prevalent cause of epileptogenic brain tumors, the natural evolution of which is much more benign than that of most gliomas. Previous studies have suggested that [11C]methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumors, and hence optimize the management of patients. Here, we reassessed the diagnostic accuracy of MET-PET for the differentiation between DNT and other epileptogenic brain neoplasms in a larger population. Methods We conducted a retrospective study of 77 patients with focal epilepsy related to a nonrapidly progressing brain tumor on MRI who underwent MET-PET, including 52 with a definite histopathology. MET-PET data were assessed by a structured visual analysis that distinguished normal, moderately abnormal, and markedly abnormal tumor methionine uptake and by semiquantitative ratio measurements. Results Pathology showed 21 DNTs (40%), 10 gangliogliomas (19%), 19 low-grade gliomas (37%), and 2 high-grade gliomas (4%). MET-PET visual findings significantly differed among the various tumor types (P < .001), as confirmed by semiquantitative analyses (P < .001 for all calculated ratios), regardless of gadolinium enhancement on MRI. All gliomas and gangliogliomas were associated with moderately or markedly increased tumor methionine uptake, whereas 9/21 DNTs had normal methionine uptake. Receiver operating characteristics analysis of the semiquantitative ratios showed an optimal cutoff threshold that distinguished DNTs from other tumor types with 90% specificity and 89% sensitivity. Conclusions Normal MET-PET findings in patients with an epileptogenic nonrapidly progressing brain tumor are highly suggestive of DNT, whereas a markedly increased tumor methionine uptake makes this diagnosis unlikely. PMID:24598358

  2. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  3. Simultaneous EEG-fMRI: perspectives in psychiatry.

    Science.gov (United States)

    Mulert, Christoph; Pogarell, Oliver; Hegerl, Ulrich

    2008-04-01

    Neurophysiological findings such as reduced amplitudes of the P300 potential in patients with schizophrenia are among the most robust findings in biological psychiatry. An enormous literature with findings of abnormal central processing in psychiatric diseases has been acquired during the last decades. However, the benefit of this research has been limited in part due to the unresolved problem of precise and correct localization of the underlying neural generators. The difficulty of correct localization is due to the fact that different constellations of cortical neuroelectric generators can produce identical EEG activity. Therefore, even concerning several major event related potentials no generally accepted knowledge about their cerebral generation exists. While correct localization can easily be obtained by imaging methods based on hemodynamic changes such as functional magnetic resonance imaging (fMRI), these techniques can not distinguish between different aspects of neural activity such as oscillation modes or stages of information processing that are only some milliseconds apart. Accordingly, the integration of simultaneous measurements of EEG and fMRI has become a methodological key issue today. EEG-fMRI may prove to be crucial in providing much deeper understanding of brain activity over the next decades. This review summarizes the basic physiology, methodological issues and interesting applications in psychiatry.

  4. Interobserver agreement of semi-automated and manual measurements of functional MRI metrics of treatment response in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Bonekamp, David; Bonekamp, Susanne; Halappa, Vivek Gowdra; Geschwind, Jean-Francois H.; Eng, John; Corona-Villalobos, Celia Pamela [The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD (United States); Pawlik, Timothy M. [The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD (United States); The Johns Hopkins School of Medicine, Department of Surgery, Oncology, Baltimore, MD (United States); Kamel, Ihab R., E-mail: ikamel@jhmi.edu [The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD (United States)

    2014-03-15

    Purpose: To assess the interobserver agreement in 50 patients with hepatocellular carcinoma (HCC) before and 1 month after intra-arterial therapy (IAT) using two semi-automated methods and a manual approach for the following functional, volumetric and morphologic parameters: (1) apparent diffusion coefficient (ADC), (2) arterial phase enhancement (AE), (3) portal venous phase enhancement (VE), (4) tumor volume, and assessment according to (5) the Response Evaluation Criteria in Solid Tumors (RECIST), and (6) the European Association for the Study of the Liver (EASL). Materials and methods: This HIPAA-compliant retrospective study had institutional review board approval. The requirement for patient informed consent was waived. Tumor ADC, AE, VE, volume, RECIST, and EASL in 50 index lesions was measured by three observers. Interobserver reproducibility was evaluated using intraclass correlation coefficients (ICC). P < 0.05 was considered to indicate a significant difference. Results: Semi-automated volumetric measurements of functional parameters (ADC, AE, and VE) before and after IAT as well as change in tumor ADC, AE, or VE had better interobserver agreement (ICC = 0.830–0.974) compared with manual ROI-based axial measurements (ICC = 0.157–0.799). Semi-automated measurements of tumor volume and size in the axial plane before and after IAT had better interobserver agreement (ICC = 0.854–0.996) compared with manual size measurements (ICC = 0.543–0.596), and interobserver agreement for change in tumor RECIST size was also higher using semi-automated measurements (ICC = 0.655) compared with manual measurements (ICC = 0.169). EASL measurements of tumor enhancement in the axial plane before and after IAT ((ICC = 0.758–0.809), and changes in EASL after IAT (ICC = 0.653) had good interobserver agreement. Conclusion: Semi-automated measurements of functional changes assessed by ADC and VE based on whole-lesion segmentation demonstrated better reproducibility than

  5. MRI of cardiovascular malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kastler, Bruno [Centre Hospitalier Univ. Jean Minjoz, Besancon (France); Universite de Franche-Comte, Besancon (FR). Lab. I4S (Health, Innovation, Intervention, Imaging, Engineering); Centre Hospitalier Sherbrooke Univ., PQ (Canada). Dept. of Radiology

    2011-07-01

    MRI is a non-invasive and non-ionizing imaging modality that is perfectly suited for the diagnosis and follow-up of both pediatric and adult congenital heart disease. It provides a large field of view and has the unique ability to depict complex cardiac and vascular anatomy and to measure cardiac function and flow within one examination. MRI is the ideal complement to echocardiography whenever the information provided by the latter is limited. This book has been conceived as a self-teaching manual that will assist qualified radiologists, cardiologists, and pediatricians, as well as those in training. It is richly illustrated with numerous images and drawings that cover all usual and most unusual anomalies. The principal author, Professor Bruno Kastler, is head of radiology at Besancon University Hospital, France and is board certified in both radiology and cardiology. (orig.)

  6. Navicular bone position determined by positional MRI

    DEFF Research Database (Denmark)

    Hansen, Philip; Johannsen, Finn E; Hangaard, Stine

    2016-01-01

    OBJECTIVE: To examine intraobserver, interobserver and between-day reproducibility of positional MRI for evaluation of navicular bone height (NVH) and medial navicular position (MNP). MATERIALS AND METHODS: Positional MRI (pMRI) of the foot was performed on ten healthy participants (0.25 T G......: Navicular height and medial navicular position can be measured by pMRI in a very reproducible manner within and between observers. Increased measurement variation is observed between-days in supine position, which may be due to small positional differences or other unknown biomechanical factors....

  7. Prediction of conversion from mild cognitive impairment to Alzheimer’s disease using MRI and structural network features

    Directory of Open Access Journals (Sweden)

    Rizhen eWei

    2016-04-01

    Full Text Available Optimized magnetic resonance imaging (MRI features and abnormalities of brain network architectures may allow earlier detection and accurate prediction of the progression from mild cognitive impairment (MCI to Alzheimer’s disease (AD. In this study, we proposed a classification framework to distinguish MCI converters (MCIc from MCI non-converters (MCInc by using a combination of FreeSurfer-derived MRI features and nodal features derived from the thickness network. At the feature selection step, we first employed sparse linear regression with stability selection, for the selection of discriminative features in the iterative combinations of MRI and network measures. Subsequently the top K features of available combinations were selected as optimal features for classification. To obtain unbiased results, support vector machine (SVM classifiers with nested cross validation were used for classification. The combination of 10 features including those from MRI and network measures attained accuracies of 66.04%, 76.39%, 74.66% and 73.91% for mixed conversion time, 6, 12 and 18 months before diagnosis of probable AD, respectively. Analysis of the diagnostic power of different time periods before diagnosis of probable AD showed that short-term prediction (6 and 12 months achieved more stable and higher AUC scores compared with long-term prediction (18 months, with K values from 1 to 30. The present results suggest that meaningful predictors composed of MRI and network measures may offer the possibility for early detection of progression from MCI to AD.

  8. Phase-Contrast MRI measurements in intra-cranial aneurysms in-vivo of flow patterns, velocity fields and wall shear stress: A comparison with CFD

    Science.gov (United States)

    Boussel, Loic; Rayz, Vitaliy; Martin, Alastair; Acevedo-Bolton, Gabriel; Lawton, Michael T.; Higashida, Randall; Smith, Wade S.; Young, William L.; Saloner, David

    2010-01-01

    Evolution of intracranial aneurysms is known to be related to hemodynamic forces such as Wall Shear Stress (WSS) and Maximum Shear Stress (MSS). Estimation of these parameters can be performed using numerical simulations (computational fluid dynamics - CFD) but can also be directly measured with MRI using a time-dependent 3D phase-contrast sequence with encoding of each of the three components of the velocity vectors (7D-MRV). In order to study the accuracy of 7D-MRV in estimating these parameters in–vivo, in comparison with CFD, 7D-MRV and patient-specific CFD modeling was performed for three patients who had intracranial aneurysms. A visual and a quantitative analysis of the flow pattern and the distribution of velocities, MSS, and WSS were performed between the two techniques. Spearman's coefficients of correlation between the two techniques were 0.56 for the velocity field, 0.48 for MSS and 0.59 for WSS. Visual analysis and Bland-Altman plots showed a good agreement for flow pattern and velocities but large discrepancies for MSS and WSS. In conclusion, these results indicate that in-vivo 7D-MRV can be used to measure velocity flow fields and to estimate MSS and WSS but is not currently able to provide accurate quantification of these two last parameters. PMID:19161132

  9. MRI-measured regression of carotid atherosclerosis induced by statins with and without niacin in a randomised controlled trial: the NIA plaque study.

    Science.gov (United States)

    Sibley, Christopher T; Vavere, Andrea L; Gottlieb, Ilan; Cox, Christopher; Matheson, Matthew; Spooner, Amy; Godoy, Gustavo; Fernandes, Veronica; Wasserman, Bruce A; Bluemke, David A; Lima, Joao A C

    2013-11-01

    To evaluate the benefit of niacin in addition to statin therapy on plaque regression among older individuals with established atherosclerosis. Randomised, controlled, double-blind clinical trial. University outpatient center. 145 patients older than 65 years, half of them older than 75 years of age, with established atherosclerosis were enrolled. Participants received either extended release niacin (1500 mg daily) or placebo in addition to statin therapy to reach their National Cholesterol Education Program-defined low density lipoprotein (LDL) cholesterol target. The primary endpoint was reduction in the wall volume of the internal carotid artery (ICA) measured by MRI. After 18 months, high density lipoprotein cholesterol was higher with statins plus niacin compared with statins alone (1.6 ± 0.4 vs 1.4 ± 0.4 mmol/L p<0.001). Both groups had significant decreases in the main outcome measure of ICA wall volume, which regressed at 0.5%/month (SEM 0.2, p=0.004) in the statins plus placebo group and at 0.7%/month in the statins plus niacin group (SEM 0.2, p<0.001). There was no difference in the rate of regression between groups (p=0.49). Treatment with statin therapy to presently recommended LDL levels, with or without niacin, resulted in significant atherosclerosis reduction.

  10. Diffusion-weighted quantitative MRI of pleural abnormalities: Intra- and interobserver variability in the apparent diffusion coefficient measurements.

    Science.gov (United States)

    Priola, Adriano Massimiliano; Priola, Sandro Massimo; Gned, Dario; Giraudo, Maria Teresa; Brundu, Maria; Righi, Luisella; Veltri, Andrea

    2017-09-01

    To assess intra- and interobserver variability in the apparent diffusion coefficient (ADC) measurements of pleural abnormalities. Diffusion-weighted magnetic resonance imaging was performed in 34 patients to characterize pleural abnormalities, with a 1.5T unit at b values of 0/150/500/800 sec/mm(2) . In two sessions held 3 months apart, on perfusion-free ADC maps, two independent readers measured the ADC of pleural abnormalities (two readings for each reader in each case) using different methods of region-of-interest (ROI) positioning. In three methods, freehand ROIs were drawn within tumor boundaries to encompass the entire lesion on one or more axial slices (whole tumor volume [WTV], three slices observer-defined [TSOD], single-slice [SS]), while in two methods one or more ROIs were placed on the more restricted areas (multiple small round ROI [MSR], one small round ROI [OSR]). Measurement variability between readings by each reader (intraobserver repeatability) and between readers in first reading (interobserver repeatability) were assessed using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Analysis of variance (ANOVA) was performed to compare ADC values between the different methods. The measurement time of each case for all methods in first reading was recorded and compared between methods and readers. All methods demonstrated good (MSR, OSR) and excellent (WTV, TSOD, SS) intra- and interreader agreement, with best and worst repeatability in WTV (lower ICC, 0.977; higher CoV, 3.5%) and OSR (lower ICC, 0.625; higher CoV, 22.8%), respectively. The lower 95% confidence interval of ICC resulted in fair to moderate agreement for OSR (up to 0.379) and in excellent agreement for WTV, TSV, and SS (up to 0.918). ADC values of OSR and MSR were significantly lower compared to other methods (P < 0.001). The OSR and SS required less measurement time (10 and 21/22 sec, respectively) compared to the others (P < 0.0001), while the WTV required

  11. Measurement of the arterial concentration of Gd-DTPA using MRI: a step toward quantitative perfusion imaging

    DEFF Research Database (Denmark)

    Fritz-Hansen, T; Rostrup, Egill; Larsson, H B

    1996-01-01

    A noninvasive method using an inversion recovery turbo-FLASH for dynamic measurement of the arterial input function represented by the bolus passage of Gd-DTPA in the descending aorta is presented, and the results are compared with the input function obtained by arterial blood samples. A good...

  12. Reproductibility of apparent diffusion coefficients measurements in diffusion-weighted MRI of the abdomen with different b values

    Energy Technology Data Exchange (ETDEWEB)

    Bilgili, Mirace Yasemin Karadeniz, E-mail: mykaradeniz@hotmail.com [Kırıkkale University Medicine Faculty, Department of Radiology, Sevil sok. 16/3 06590 Cebeci/Ankara (Turkey)

    2012-09-15

    Purpose: To test the reproducibility of apparent diffusion coefficients (ADC) measurements of the normal liver, kidney and spleen parenchyma with different b values. Materials and methods: Eleven healthy volunteers were imaged twice with use of the same protocol. Each DWI was performed with b-factors of 0, 100 and 500 s/mm{sup 2}. The ADCs were organized according to session (1 or 2), anatomic location and repetition (twice with two different b value per session). The ADC data were analyzed with repeated-measures analysis of variance to demonstrate the influence of anatomic location, session and different b values. The coefficient of variation was calculated for each subject, b value and anatomic location, then analyzed by using repeated-measures analysis of variance. Results: There were significant differences in mean ADCs among the three anatomic locations and with different b values (P < .05). There were no significant differences in ADCs between imaging sessions 1 or 2 for both b values (P > .05). The CV values range between 7.3% and 14.7%. There were no significant differences in CV values neither between the two b values nor for the various organ locations (P > .05). Conclusion: Using the same technical parameters, patients and the same observer, CV values range between 7.3% and 14.7%. And we recommend to be careful in examination and comparison of the measured ADC values, below these limits, without knowledge technical parameters that has been used, otherwise differences that are merely because of changes in the measurement technique could be interpreted as differences because of progression of disease or therapy.

  13. fMRI-compatible rehabilitation hand device

    OpenAIRE

    Tzika Aria; Astrakas Loukas; Weinberg Brian; Triantafyllou Christina; Muto Andrew; Khanicheh Azadeh; Mavroidis Constantinos

    2006-01-01

    Abstract Background Functional magnetic resonance imaging (fMRI) has been widely used in studying human brain functions and neurorehabilitation. In order to develop complex and well-controlled fMRI paradigms, interfaces that can precisely control and measure output force and kinematics of the movements in human subjects are needed. Optimized state-of-the-art fMRI methods, combined with magnetic resonance (MR) compatible robotic devices for rehabilitation, can assist therapists to quantify, mo...

  14. MRI volumetry for the preoperative diagnosis of trigeminal neuralgia

    Energy Technology Data Exchange (ETDEWEB)

    Kress, Bodo; Schindler, Markus; Haehnel, Stefan; Sartor, Klaus; Stippich, Christoph [University of Heidelberg, Division of Neuroradiology, Department of Neurology, Medical Center, 69120 Heidelberg (Germany); Rasche, Dirk; Tronnier, Volker [University of Heidelberg, Department of Neurosurgery, Medical Center, 69120 Heidelberg (Germany)

    2005-07-01

    To assess whether quantitative measuring methods can help improve the reliability of MRI-based evaluations of the pathological role of a neurovascular conflict between an artery and the trigeminal nerve. In a prospective study, magnetic resonance images were obtained from 62 patients with unilateral facial pain and 50 healthy test subjects. In coronal T1- and T2-weighted sequences volume measurements were performed by regions of interest and compared intraindividually (healthy versus affected side in the patient populations and right versus left side in the group of test subjects) and on the basis of the different clinical pictures (t test for dependent and independent samples, p<0.05). In patients with trigeminal neuralgia, the affected nerve showed a smaller volume than the trigeminal nerve on the healthy side (p<0.001). Such a volume difference was noted neither in the other patients nor in the healthy test subjects. Quantitative MRI measurements allow a pathological neurovascular conflict to be distinguished from a nonpathological condition where an artery is in close proximity to the trigeminal nerve. The measured volume difference between the healthy and the affected nerve in patients with neuralgia is indicative of trigeminal nerve atrophy resulting from damage to the nerve. (orig.)

  15. Support Vector Machine Classification For MRI Images

    OpenAIRE

    Rajeswari S; Theiva Jeyaselvi. K

    2012-01-01

    -Magnetic resonance imaging (MRI) is an imaging technique that has played an important role in neuro science research for studying brain images. Classification is an important part in order to distinguish between normal patients and those who have the p o s s i b i l i t y o f h a v i n g a b n o r m a l i t i e s o r tumor. In this paper, we have obtained the texture based features such as GLCM (Grey Level Co-occurrence Matrix) of MRI images. To select the discriminative features among them ...

  16. Ask for advice of measurement nuclrar magnetic resonance image(MRI)%关于对医用核磁共振成像(MRI)系统检测的探讨

    Institute of Scientific and Technical Information of China (English)

    郭洪涛; 张莹

    2005-01-01

    通过这篇学术文章,对全国各地技术机构正在进行的检测核磁共振成像(MRI)系统中如何正确操作、正确处理数据及客观评价起到积极的作用.所采用的方法是北美放射物理学会(AAPM)和美国国家电气生产厂家标准(NEMA)推荐的方法.从近几年来对北京地区新安装的、使用中几十台磁共振成像系统(MRI)进行了检测结果表明,采用AAPM建议书和NEMA标准所规定的方法对中国开展核磁共振成像(MRI)系统中图像的检测是可行的,也是必须的.对我们今后正在制定国家级是非常有益的.

  17. Short-term MRI measurements as predictors of EDSS progression in relapsing-remitting multiple sclerosis: grey matter atrophy but not lesions are predictive in a real-life setting.

    Science.gov (United States)

    von Gumberz, Johanna; Mahmoudi, Mina; Young, Kim; Schippling, Sven; Martin, Roland; Heesen, Christoph; Siemonsen, Susanne; Stellmann, Jan-Patrick

    2016-01-01

    Magnetic resonance imaging (MRI) is the best biomarker of inflammatory disease activity in relapsing remitting Multiple Sclerosis (RRMS) so far but the association with disability is weak. Appearance of new MRI-lesions is used to evaluate response to immunotherapies in individual patients as well as being the most common primary outcome in phase-2 trials. Measurements of brain atrophy show promising outcomes in natural cohort studies and some phase-2 trials. From a theoretical perspective they might represent irreversible neurodegeneration and be more closely associated with disability. However, these atrophy measurements are not yet established as prognostic factors in real-life clinical routine. High field MRI has improved image quality and resolution and new methods to measure atrophy dynamics have become available. To investigate the predictive value of MRI classification criteria in to high/low atrophy and inflammation groups, and to explore predictive capacity of two consecutive routine MRI scans for disability progression in RRMS in a real-life prospective cohort. 82 RRMS-patients (40 untreated, 42 treated with immunotherapies, mean age 40 years, median Expanded Disability Status Scale (EDSS) of 2, underwent two clinically indicated MRI scans (3 Tesla) within 5-14 months, and EDSS assessment after a mean of 3.0 (1.5-4.2) years. We investigated the predictive value of predefined classifications in low/high inflammatory and atrophy groups for EDSS progression (≥1.5 if baseline EDSS = 0, ≥1.0 if baseline EDSS EDSS and higher grey matter atrophy (FreeSurfer) as best predictors (R (2) = 0.29) for EDSS progression and the accuracy was overall good (Area under the curve = 0.81). Beside EDSS at baseline, short-term grey matter atrophy is predictive for EDSS progression in treated and untreated RRMS. The development of atrophy measurements for individual risk counselling and evaluation of treatment response seems possible, but needs further validation in larger

  18. MRI evaluation of vascular dementia

    Institute of Scientific and Technical Information of China (English)

    Yicheng Liu; Hongxing Zhang; Wei Huang; Wenjun Wan; Hongfen Peng

    2006-01-01

    OBJECTTVE: To explain the association between vascular dementia and the cranial MRI manifestations, and recognize the value of cranial MRI in the early diagnosis of vascular dementia and the assessment of disease conditions.DATA SOURCES: Pubmed database was searched to identify articles about the cranial MRI manifestations of patients with vascular dementia published in English from January 1992 to June 2006 by using the key words of "MRI, vascular dementia". Others were collected by searching the name of journals and title of articles in the Chinese full-text journal database.STUDY SELECTTON: The collected articles were primarily checked, those correlated with the cranial MRI manifestations of patients with vascular dementia were selected, while the obviously irrelative ones were excluded, and the rest were retrieved manually, the full-texts were searched.DATA EXTRACTION: Totally 255 articles were collected, 41 of them were involved, and the other 214 were excluded.DATA SYNTHESIS: MRI can be taken as one of the effective methods for the early diagnosis and disease evaluation of vascular dementia. White matter lesions are the important risk factors of vascular dementia.Vascular dementia is accompanied by the atrophy of related brain sites, but further confirmation is needed to investigate whether there is significant difference. MRI can be used to quantitatively investigate the infarcted sites and sizes of patients with vascular dementia after infarction, but there is still lack of systematic investigation on the association of the infarcted sites and sizes with the cognitive function of patients with vascular dementia.CONCLUSTON: Cranial MRI can detect the symptoms of vascular dementia at early period, so that corresponding measures can be adopted to prevent and treat vascular dementia in time.

  19. Precise measurement of renal filtration and vascular parameters using a two-compartment model for dynamic contrast-enhanced MRI of the kidney gives realistic normal values

    Energy Technology Data Exchange (ETDEWEB)

    Tofts, Paul S. [Brighton and Sussex Medical School, Falmer, Sussex (United Kingdom); UCL Institute of Neurology, London (United Kingdom); Cutajar, Marica [Brighton and Sussex Medical School, Falmer, Sussex (United Kingdom); UCL Institute of Child Health, London (United Kingdom); Mendichovszky, Iosif A. [University of Manchester, Imaging Science and Biomedical Engineering, Manchester (United Kingdom); Peters, A.M. [Brighton and Sussex Medical School, Falmer, Sussex (United Kingdom); Gordon, Isky [UCL Institute of Child Health, London (United Kingdom)

    2012-06-15

    To model the uptake phase of T{sub 1}-weighted DCE-MRI data in normal kidneys and to demonstrate that the fitted physiological parameters correlate with published normal values. The model incorporates delay and broadening of the arterial vascular peak as it appears in the capillary bed, two distinct compartments for renal intravascular and extravascular Gd tracer, and uses a small-vessel haematocrit value of 24%. Four physiological parameters can be estimated: regional filtration K{sup trans} (ml min {sup -1} [ml tissue ]{sup -1}), perfusion F (ml min {sup -1} [100 ml tissue ]{sup -1}), blood volume v{sub b} (%) and mean residence time MRT (s). From these are found the filtration fraction (FF; %) and total GFR (ml min {sup -1}). Fifteen healthy volunteers were imaged twice using oblique coronal slices every 2.5 s to determine the reproducibility. Using parenchymal ROIs, group mean values for renal biomarkers all agreed with published values: K{sup trans}: 0.25; F: 219; v{sub b}: 34; MRT: 5.5; FF: 15; GFR: 115. Nominally cortical ROIs consistently underestimated total filtration (by {proportional_to} 50%). Reproducibility was 7-18%. Sensitivity analysis showed that these fitted parameters are most vulnerable to errors in the fixed parameters kidney T{sub 1}, flip angle, haematocrit and relaxivity. These renal biomarkers can potentially measure renal physiology in diagnosis and treatment. circle Dynamic contrast-enhanced magnetic resonance imaging can measure renal function. circle Filtration and perfusion values in healthy volunteers agree with published normal values. circle Precision measured in healthy volunteers is between 7 and 15%. (orig.)

  20. T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation

    Energy Technology Data Exchange (ETDEWEB)

    Wedegaertner, Ulrike; Adam, Gerhard [Universitaetsklinikum Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Kooijman, Hendrik [Philips Medical Systems, Best (Netherlands); Andreas, Thomas; Beindorff, Nicola; Hecher, Kurt [University Hospital Hamburg-Eppendorf, Department of Obstetrics and Prenatal Medicine, Hamburg (Germany)

    2010-01-15

    The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO{sub 2}) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO{sub 2}) was measured during the two experimental phases. The slope of MR-sO{sub 2} as a function of blood-sO{sub 2} was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO{sub 2}. During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO{sub 2} decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0(T=5.023, df=4, P=0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO{sub 2} and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible. (orig.)

  1. Genetic correlates of brain aging on MRI and cognitive test measures: a genome-wide association and linkage analysis in the Framingham study

    OpenAIRE

    2007-01-01

    Abstract Background Brain magnetic resonance imaging (MRI) and cognitive tests can identify heritable endophenotypes associated with an increased risk of developing stroke, dementia and Alzheimer's disease (AD). We conducted a genome-wide association (GWA) and linkage analysis exploring the genetic basis of these endophenotypes in a community-based sample. Methods A total of 705 stroke- and dementia-free Framingham participants (age 62 +9 yrs, 50% male) who underwent volumetric brain MRI and ...

  2. Changes in Cerebral Blood Flow in Presymptomatic Mutation Carriers of Familial Frontotemporal Dementia (FTD-3), Measured with MRI

    DEFF Research Database (Denmark)

    Lunau, Line Andersen; Mouridsen, Kim; Rodell, Anders

    , temporal, parietal, and occipital lobes, hippocampus, basal ganglia and cerebellum. Data were normalized to white matter in order to smooth inter-individual differences. Results: We included 8 carriers and 7 first-degree related family non-carriers. Comparing carriers with non-carriers, the former showed...... decreased mean CBF values at the capillary level in all ROIs, with significant changes in capillary CBF in the parietal (mean change 14 %; p = 0.03) and occipital (mean change 9 %; p = 0.02) lobes. Conclusions: Decreased cerebral blood flow can be measured in presymptomatic CHMP2B mutation carriers...... with statistically significant differences in the occipital- and parietal lobes. Alterations in CBF possibly affect the whole brain. Data indicate that FTD-3 pathology might involve brain capillaries. This may impact the understanding of the pathogenesis involving endosomal dysfunction and implicates involvement...

  3. Diffusion measurement of intraplaque hemorrhage and intramural hematoma using diffusion weighted MRI at 3T in cervical artery

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Bin [The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi (China); Yang, Li [Fudan University, Department of Radiology, Shanghai Institute of Medical Imaging, Zhongshan Hospital, Shanghai (China); Wang, Guangbin; Shi, Honglu; Wang, Shanshan; Li, Huihua [Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Chen, Weibo; Chan, Queenie [Philips Healthcare, Shanghai (China)

    2016-10-15

    To assess the difference between carotid haemorrhagic plaque and non-haemorrhagic plaque by using diffusion-weighted imaging (DWI) and to evaluate carotid intraplaque haemorrhage (IPH) and intramural hematoma (IMH) of cervical artery dissection with apparent diffusion coefficient (ADC) measurement. Fifty-one symptomatic patients underwent 3.0-T carotid MR imaging, including conventional sequences, three-dimensional (3D) magnetization-prepared rapid acquisition gradient-echo (MPRAGE) sequence, and DWI. Thirty-nine patients with carotid plaque and eight patients with IMH of cervical artery dissection were finally included. The groups of hemorrhagic plaque, non-hemorrhagic plaque and IMH were divided according to 3D MPRAGE sequence. ADC values of different groups were measured, and t tests were performed. The mean ADC values of hemorrhagic plaques, non-hemorrhagic plaque and IMH were (1.284 ± 0.327) x 10{sup -3}mm{sup 2}/s, (1.766 ± 0.477) x 10{sup -3}mm{sup 2}/s, and (0.563 ± 0.119) x 10{sup -3}mm{sup 2}/s, respectively. The mean ADC values of hemorrhagic and non-hemorrhagic regions in the hemorrhagic plaque group were (0.985 ± 0.376) x 10{sup -3}mm{sup 2}/s and (1.480 ± 0.465) x 10{sup -3}mm{sup 2}/s, respectively. The differences between the hemorrhagic plaque and non-hemorrhagic plaque, hemorrhagic region and non-hemorrhagic region in hemorrhagic plaque, and the hemorrhagic region in the hemorrhagic plaque and IMH of artery dissection were significant (P < 0.05). DWI may be a useful complement to conventional MR imaging for identifying haemorrhage of carotid plaques and differentiate IMHs from IPH. (orig.)

  4. The impact of simulated MRI scanner background noise on visual attention processes as measured by the EEG.

    Science.gov (United States)

    Kobald, S Oliver; Getzmann, Stephan; Beste, Christian; Wascher, Edmund

    2016-06-21

    Environmental noise is known to affect personal well-being as well as cognitive processes. Besides daily life, environmental noise can also occur in experimental research settings, e.g. when being in a magnetic resonance scanner. Scanner background noise (SBN) might pose serious confounds for experimental findings, even when non-auditory settings are examined. In the current experiment we tested if SBN alters bottom-up and top-down related processes of selective visual attention mechanisms. Participants completed two blocks of a visual change detection task, one block in silence and one block under SBN exposure. SBN was found to decrease accuracy in measures of visual attention. This effect was modulated by the temporal occurrence of SBN. When SBN was encountered in the first block, it prevented a significant improvement of accuracy in the second block. When SBN appeared in the second block, it significantly decreased accuracy. Neurophysiological findings showed a strong frontal positivity shift only when SBN was present in the first block, suggesting an inhibitory process to counteract the interfering SBN. Common correlates of both top-down and bottom-up processes of selective visual attention were not specifically affected by SBN exposure. Further research appears necessary to entirely rule out confounds of SBN in assessing visual attention.

  5. The impact of simulated MRI scanner background noise on visual attention processes as measured by the EEG

    Science.gov (United States)

    Kobald, S. Oliver; Getzmann, Stephan; Beste, Christian; Wascher, Edmund

    2016-01-01

    Environmental noise is known to affect personal well-being as well as cognitive processes. Besides daily life, environmental noise can also occur in experimental research settings, e.g. when being in a magnetic resonance scanner. Scanner background noise (SBN) might pose serious confounds for experimental findings, even when non-auditory settings are examined. In the current experiment we tested if SBN alters bottom-up and top-down related processes of selective visual attention mechanisms. Participants completed two blocks of a visual change detection task, one block in silence and one block under SBN exposure. SBN was found to decrease accuracy in measures of visual attention. This effect was modulated by the temporal occurrence of SBN. When SBN was encountered in the first block, it prevented a significant improvement of accuracy in the second block. When SBN appeared in the second block, it significantly decreased accuracy. Neurophysiological findings showed a strong frontal positivity shift only when SBN was present in the first block, suggesting an inhibitory process to counteract the interfering SBN. Common correlates of both top-down and bottom-up processes of selective visual attention were not specifically affected by SBN exposure. Further research appears necessary to entirely rule out confounds of SBN in assessing visual attention. PMID:27324456

  6. single voxel magnetic resonance spectroscopy in distinguishing ...

    African Journals Online (AJOL)

    2011-03-03

    Mar 3, 2011 ... magnetic resonance spectroscopy (MRI, MRS) in differentiating focal neoplastic lesions from focal non- ..... this study, it is important to note that there were distinct differences in the .... Applications of MRS in the. 13. evaluation ...

  7. Distinguishing Cartesian Products of Countable Graphs

    Directory of Open Access Journals (Sweden)

    Estaji Ehsan

    2017-02-01

    Full Text Available The distinguishing number D(G of a graph G is the minimum number of colors needed to color the vertices of G such that the coloring is preserved only by the trivial automorphism. In this paper we improve results about the distinguishing number of Cartesian products of finite and infinite graphs by removing restrictions to prime or relatively prime factors.

  8. Changes in brain connectivity related to the treatment of depression measured through fMRI: a systematic review

    Science.gov (United States)

    Gudayol-Ferré, Esteve; Peró-Cebollero, Maribel; González-Garrido, Andrés A.; Guàrdia-Olmos, Joan

    2015-01-01

    Depression is a mental illness that presents alterations in brain connectivity in the Default Mode Network (DMN), the Affective Network (AN) and other cortical-limbic networks, and the Cognitive Control Network (CCN), among others. In recent years the interest in the possible effect of the different antidepressant treatments on functional connectivity has increased substantially. The goal of this paper is to conduct a systematic review of the studies on the relationship between the treatment of depression and brain connectivity. Nineteen studies were found in a systematic review on this topic. In all of them, there was improvement of the clinical symptoms after antidepressant treatment. In 18 out of the 19 studies, clinical improvement was associated to changes in brain connectivity. It seems that both DMN and the connectivity between cortical and limbic structures consistently changes after antidepressant treatment. However, the current evidence does not allow us to assure that the treatment of depression leads to changes in the CCN. In this regard, some papers report a positive correlation between changes in brain connectivity and improvement of depressive symptomatology, particularly when they measure cortical-limbic connectivity, whereas the changes in DMN do not significantly correlate with clinical improvement. Finally, some papers suggest that changes in connectivity after antidepressant treatment might be partly related to the mechanisms of action of the treatment administered. This effect has been observed in two studies with stimulation treatment (one with rTMS and one with ECT), and in two papers that administered three different pharmacological treatments. Our review allows us to make a series of recommendations that might guide future researchers exploring the effect of anti-depression treatments on brain connectivity. PMID:26578927

  9. CHANGES IN BRAIN CONNECTIVITY RELATED TO THE TREATMENT OF DEPRESSION MEASURED THROUGH fMRI: A SYSTEMATIC REVIEW

    Directory of Open Access Journals (Sweden)

    Esteve eGudayol-Ferré

    2015-11-01

    Full Text Available Depression is a mental illness that presents alterations of brain connectivity in the Default Mode Network, the Affective Network and other cortical-limbic networks, and the Cognitive Control Network (CCN among others. In recent years the interest in the possible effect of the different antidepressant treatments on functional connectivity has increased substantially. The goal of this paper is to conduct a systematic review of the studies on the relationship between the treatment of depression and brain connectivity. Nineteen studies were found in the systematic review on this topic. In all of them, there was improvement of the clinical symptoms after antidepressant treatment. In 18 out of the 19 studies, clinical improvement was associated to changes in brain connectivity. It seems that both DMN and the connectivity between cortical and limbic structures consistently change after antidepressant treatment. However, the current evidence does not allow us to assure that the treatment of depression lead to changes in the CCN. In this regard, some papers report a positive correlation between changes in brain connectivity and improvement of depressive symptomatology, particularly when they measure cortical-limbic connectivity, whereas the changes in DMN do not significantly correlate with clinical improvement. Finally, some papers suggest that changes in connectivity after antidepressant treatment might be partly related to the mechanisms of action of the treatment administered. This effect has been observed in two studies with stimulation treatment (one with rTMS and one with ECT, and in two papers that administered three different pharmacological treatments. us to make a series of recommendations that, on the one hand, might guide future researchers exploring the effect of anti-depression treatments on brain connectivity.

  10. Multimodal assessments of the hippocampal formation in schizophrenia and bipolar disorder: Evidences from neurobehavioral measures and functional and structural MRI

    Directory of Open Access Journals (Sweden)

    Christian Knöchel

    2014-01-01

    Full Text Available A potential clinical and etiological overlap between schizophrenia (SZ and bipolar disorder (BD has long been a subject of discussion. Imaging studies imply functional and structural alterations of the hippocampus in both diseases. Thus, imaging this core memory region could provide insight into the pathophysiology of these disorders and the associated cognitive deficits. To examine possible shared alterations in the hippocampus, we conducted a multi-modal assessment, including functional and structural imaging as well as neurobehavioral measures of memory performance in BD and SZ patients compared with healthy controls. We assessed episodic memory performance, using tests of verbal and visual learning (HVLT, BVMT in three groups of participants: BD patients (n = 21, SZ patients (n = 21 and matched (age, gender, education healthy control subjects (n = 21. In addition, we examined hippocampal resting state functional connectivity, hippocampal volume using voxel-based morphometry (VBM and fibre integrity of hippocampal connections using diffusion tensor imaging (DTI. We found memory deficits, changes in functional connectivity within the hippocampal network as well as volumetric reductions and altered white matter fibre integrity across patient groups in comparison with controls. However, SZ patients when directly compared with BD patients were more severely affected in several of the assessed parameters (verbal learning, left hippocampal volumes, mean diffusivity of bilateral cingulum and right uncinated fasciculus. The results of our study suggest a graded expression of verbal learning deficits accompanied by structural alterations within the hippocampus in BD patients and SZ patients, with SZ patients being more strongly affected. Our findings imply that these two disorders may share some common pathophysiological mechanisms. The results could thus help to further advance and integrate current pathophysiological models of SZ and BD.

  11. Conservatively treated knee injury is associated with knee cartilage matrix degeneration measured with MRI-based T2 relaxation times: data from the osteoarthritis initiative.

    Science.gov (United States)

    Hofmann, Felix C; Neumann, Jan; Heilmeier, Ursula; Joseph, Gabby B; Nevitt, Michael C; McCulloch, Charles E; Link, Thomas M

    2017-08-29

    To investigate the association of cartilage degeneration with previous knee injuries not undergoing surgery, determined by morphologic and quantitative 3-T magnetic resonance imaging (MRI). We performed a nested cross-sectional study of right knee MRIs from participants in the Osteoarthritis Initiative (OAI) aged 45-79 with baseline Kellgren-Lawrence score of 0-2. Cases were 142 right knees of patients with self-reported history of injury limiting the ability to walk for at least 2 days. Controls were 426 right knees without history of injury, frequency-matched to cases on age, BMI, gender, KL scores and race (1:3 ratio). Cases and controls were compared using covariate-adjusted linear regression analysis, with the outcomes of region-specific T2 mean, laminar analysis and heterogeneity measured by texture analysis to investigate early cartilage matrix abnormalities and the Whole-Organ Magnetic Resonance Imaging Score (WORMS) to investigate morphologic knee lesions. Compared to control subjects, we found significantly higher mean T2 values in the injury [lateral tibia (28.10 ms vs. 29.11 ms, p = 0.001), medial tibia (29.70 ms vs. 30.40 ms, p = 0.014) and global knee cartilage (32.73 ms vs. 33.29 ms, p = 0.005)]. Injury subjects also had more heterogeneous cartilage as measured by GLCM texture contrast, variance and entropy (p  0.05). A history of knee injury not treated surgically is associated with higher and more heterogeneous T2 values, but not with morphologic knee abnormalities. Our findings suggest that significant, conservatively treated knee injuries are associated with permanent cartilage matrix abnormalities.

  12. Fasting and postprandial volumes of the undisturbed colon: normal values and changes in diarrhea-predominant irritable bowel syndrome measured using serial MRI.

    Science.gov (United States)

    Pritchard, S E; Marciani, L; Garsed, K C; Hoad, C L; Thongborisute, W; Roberts, E; Gowland, P A; Spiller, R C

    2014-01-01

    Previous assessments of colon morphology have relied on tests which were either invasive or used ionizing radiation. We aimed to measure regional volumes of the undisturbed colon in healthy volunteers (HV) and patients with diarrhea-predominant irritable bowel syndrome (IBS-D). 3D regional (ascending, transverse, and descending) colon volumes were measured in fasting abdominal magnetic resonance (MR) images of 75 HVs and 25 IBS-D patients. Thirty-five of the HV and all 25 IBS-D subjects were fed a standard meal and postprandial MRI data obtained over 225 min. Colonic regions were identified and 3D maps from cecum to sigmoid flexure were defined. Fasted regional volumes showed wide variation in both HVs being (mean ± SD) ascending colon (AC) 203 ± 75 mL, transverse (TC) 198 ± 79 mL, and descending (DC) 160 ± 86 mL with no difference from IBS-D subjects (AC 205 ± 69 mL, TC 232 ± 100 mL, and DC 151 ± 71 mL, respectively). The AC volume expanded by 10% after feeding (p = 0.007) in the 35 HV possibly due to increased ileo-colonic inflow. A later rise in AC volume occurred from t = 90 to t = 240 min as the meal residue entered the cecum. In contrast, IBS-D subjects showed a much reduced postprandial response of the AC (p colon in fasted and fed states. The AC in IBS-D appeared less able to accommodate postprandial inflow which may account for faster colonic transit. © 2013 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.

  13. How bees distinguish black from white

    Directory of Open Access Journals (Sweden)

    Horridge A

    2014-10-01

    Full Text Available Adrian Horridge Biological Sciences, Australian National University, Canberra, ACT, AustraliaAbstract: Bee eyes have photoreceptors for ultraviolet, green, and blue wavelengths that are excited by reflected white but not by black. With ultraviolet reflections excluded by the apparatus, bees can learn to distinguish between black, gray, and white, but theories of color vision are clearly of no help in explaining how they succeed. Human vision sidesteps the issue by constructing black and white in the brain. Bees have quite different and accessible mechanisms. As revealed by extensive tests of trained bees, bees learned two strong signals displayed on either target. The first input was the position and a measure of the green receptor modulation at the vertical edges of a black area, which included a measure of the angular width between the edges of black. They also learned the average position and total amount of blue reflected from white areas. These two inputs were sufficient to help decide which of two targets held the reward of sugar solution, but the bees cared nothing for the black or white as colors, or the direction of contrast at black/white edges. These findings provide a small step toward understanding, modeling, and implementing in silicon the anti-intuitive visual system of the honeybee, in feeding behavior. Keywords: vision, detectors, black/white, color, visual processing

  14. Predictive MRI correlates of lesser metatarsophalangeal joint plantar plate tear

    Energy Technology Data Exchange (ETDEWEB)

    Umans, Rachel L. [Cornell University Medical College, New York, NY (United States); Umans, Benjamin D. [Harvard University, Cambridge, MA (United States); Umans, Hilary [Albert Einstein College of Medicine, Bronx, NY (United States); Lenox Hill Radiology and Imaging Associates, New York, NY (United States); Elsinger, Elisabeth [Albert Einstein College of Medicine, Bronx, NY (United States); Montefiore Medical Center, Bronx, NY (United States)

    2016-07-15

    To identify correlated signs on non-enhanced MRI that might improve diagnostic detection of plantar plate (PP) tear. We performed an IRB-approved, HIPAA-compliant retrospective analysis of 100 non-contrast MRI (50 PP tear, 50 controls). All were anonymized, randomized, and reviewed; 20 were duplicated to assess consistency. One musculoskeletal radiologist evaluated qualitative variables. A trained non-physician performed measurements. Consistency and concordance were assessed. Pearson's Chi-square test was used to test the correlation between qualitative findings and PP tear status. Correlation between measurements and PP status was assessed using t tests and Wilcoxon's rank-sum test (p values < 0.05 considered significant). Classification and regression trees were utilized to identify attributes that, taken together, would consistently distinguish PP tear from controls. Quantitative measurements were highly reproducible (concordance 0.88-0.99). Elevated 2nd MT protrusion, lesser MT supination and rotational divergence of >45 between the 1st-2nd MT axis correlated with PP tear. Pericapsular soft tissue thickening correlated most strongly with PP tear, correctly classifying 95 % of cases and controls. Excluding pericapsular soft tissue thickening, sequential assessment of 2nd toe enthesitis, 2nd flexor tendon subluxation, and splaying of the second and third toes accurately classified PP status in 92 %. Pericapsular soft tissue thickening most strongly correlated with PP tear. For cases in which it might be difficult to distinguish pericapsular fibrosis from neuroma, sequential assessment of 2nd toe enthesitis, flexor tendon subluxation and splaying of the 2nd and 3rd toe is most helpful for optimizing accurate diagnosis of PP tear. (orig.)

  15. Improved measurement of labile proton concentration-weighted chemical exchange rate (k(ws)) with experimental factor-compensated and T(1) -normalized quantitative chemical exchange saturation transfer (CEST) MRI.

    Science.gov (United States)

    Wu, Renhua; Liu, Charng-Ming; Liu, Philip K; Sun, Phillip Zhe

    2012-01-01

    Chemical exchange saturation transfer (CEST) MRI enables measurement of dilute CEST agents and microenvironment properties such as pH and temperature, holding great promise for in vivo applications. However, because of confounding concomitant radio frequency (RF) irradiation and relaxation effects, the CEST-weighted MRI contrast may not fully characterize the underlying CEST phenomenon. We postulated that the accuracy of quantitative CEST MRI could be improved if the experimental factors (labeling efficiency and RF spillover effect) were estimated and taken into account. Specifically, the experimental factor was evaluated as a function of exchange rate and CEST agent concentration ratio, which remained relatively constant for intermediate RF irradiation power levels. Hence, the experimental factors can be calculated based on the reasonably estimated exchange rate and labile proton concentration ratio, which significantly improved quantification. The simulation was confirmed with creatine phantoms of serially varied concentration titrated to the same pH, whose reverse exchange rate (k(ws)) was found to be linearly correlated with the concentration. In summary, the proposed solution provides simplified yet reasonably accurate quantification of the underlying CEST system, which may help guide the ongoing development of quantitative CEST MRI.

  16. Simultaneous PET/MR imaging of the brain: feasibility of cerebral blood flow measurements with FAIR-TrueFISP arterial spin labeling MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stegger, Lars [Dept. of Radiology, Diagnostic and Interventional Radiology, Eberhard Karls Univ. Tuebingen, Tuebingen (Germany); Dept. of Nuclear Medicine and European Inst. for Molecular Imaging, Univ. of Munster, Munster (Germany)], E-mail: stegger@uni-muenster.de; Martirosian, Petros; Schick, Fritz [Dept. of Radiology, Section of Experimental Radiology, Eberhard Karls Univ. Tuebingen, Tuebingen (Germany); Schwenzer, Nina; Pfannenberg, Christina; Claussen, Claus D. [Dept. of Radiology, Diagnostic and Interventional Radiology, Eberhard Karls Univ. Tuebingen, Tuebingen (Germany); Bisdas, Sotirios [Dept. of Radiology, Diagnostic and Interventional Neuroradiology, Eberhard Karls Univ. Tuebingen, Tuebingen (Germany); Kolb, Armin; Pichler, Bernd [Dept. of Preclinical Imaging and Radiopharmacy, Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, Eberhard Karls Univ. Tuebingen, Tuebingen (Germany); Boss, Andreas [Dept. of Radiology, Diagnostic and Interventional Radiology, Eberhard Karls Univ. Tuebingen, Tuebingen (Germany); Inst. of Diagnostic and Interventional Radiology, Univ. Hospital Zurich, Zurich (Switzerland)

    2012-11-15

    Background Hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) with simultaneous data acquisition promises a comprehensive evaluation of cerebral pathophysiology on a molecular, anatomical, and functional level. Considering the necessary changes to the MR scanner design the feasibility of arterial spin labeling (ASL) is unclear. Purpose To evaluate whether cerebral blood flow imaging with ASL is feasible using a prototype PET/MRI device. Material and Methods ASL imaging of the brain with Flow-sensitive Alternating Inversion Recovery (FAIR) spin preparation and true fast imaging in steady precession (TrueFISP) data readout was performed in eight healthy volunteers sequentially on a prototype PET/MRI and a stand-alone MR scanner with 128 x 128 and 192 x 192 matrix sizes. Cerebral blood flow values for gray matter, signal-to-noise and contrast-to-noise ratios, and relative signal change were compared. Additionally, the feasibility of ASL as part of a clinical hybrid PET/MRI protocol was demonstrated in five patients with intracerebral tumors. Results Blood flow maps showed good delineation of gray and white matter with no discernible artifacts. The mean blood flow values of the eight volunteers on the PET/MR system were 51 {+-} 9 and 51 {+-} 7 mL/100 g/min for the 128 x 128 and 192 x 192 matrices (stand-alone MR, 57 {+-} 2 and 55 {+-} 5, not significant). The value for signal-to-noise (SNR) was significantly higher for the PET/MRI system using the 192 x 192 matrix size (P < 0.01), the relative signal change (dS) was significantly lower for the 192 x 192 matrix size (P = 0.02). ASL imaging as part of a clinical hybrid PET/MRI protocol could successfully be accomplished in all patients in diagnostic image quality. Conclusion ASL brain imaging is feasible with a prototype hybrid PET/MRI scanner, thus adding to the value of this novel imaging technique.

  17. In vivo measurement of changes in venous blood-oxygenation with high resolution functional MRI at 0.95 tesla by measuring changes in susceptibility and velocity.

    Science.gov (United States)

    Hoogenraad, F G; Reichenbach, J R; Haacke, E M; Lai, S; Kuppusamy, K; Sprenger, M

    1998-01-01

    High-resolution functional imaging experiments at 0.95 Tesla have been performed to determine the changes in oxygen saturation in pial veins during motor activation by measuring both flow and susceptibility changes in the blood. Averaging across subjects, mean values for the change of the oxygenation level, deltaY = 0.16 +/- 0.08 (n = 7) and deltaY = 0.13 +/- 0.09 (n = 4), were obtained from the susceptibility sensitive and the flow sensitive acquisitions, respectively. The results suggest that the increase in blood flow is largely uncoupled from the oxygen consumption. The quoted errors reflect mainly the intersubject variability. In addition, low-resolution echo planar imaging (EPI) measurements were performed on the same volunteers to quantify signal intensity changes. Using the measured change in oxygenation, the observed signal changes in the EPI experiments can be attributed to a 5% venous blood volume.

  18. Classification algorithms with multi-modal data fusion could accurately distinguish neuromyelitis optica from multiple sclerosis.

    Science.gov (United States)

    Eshaghi, Arman; Riyahi-Alam, Sadjad; Saeedi, Roghayyeh; Roostaei, Tina; Nazeri, Arash; Aghsaei, Aida; Doosti, Rozita; Ganjgahi, Habib; Bodini, Benedetta; Shakourirad, Ali; Pakravan, Manijeh; Ghana'ati, Hossein; Firouznia, Kavous; Zarei, Mojtaba; Azimi, Amir Reza; Sahraian, Mohammad Ali

    2015-01-01

    Neuromyelitis optica (NMO) exhibits substantial similarities to multiple sclerosis (MS) in clinical manifestations and imaging results and has long been considered a variant of MS. With the advent of a specific biomarker in NMO, known as anti-aquaporin 4, this assumption has changed; however, the differential diagnosis remains challenging and it is still not clear whether a combination of neuroimaging and clinical data could be used to aid clinical decision-making. Computer-aided diagnosis is a rapidly evolving process that holds great promise to facilitate objective differential diagnoses of disorders that show similar presentations. In this study, we aimed to use a powerful method for multi-modal data fusion, known as a multi-kernel learning and performed automatic diagnosis of subjects. We included 30 patients with NMO, 25 patients with MS and 35 healthy volunteers and performed multi-modal imaging with T1-weighted high resolution scans, diffusion tensor imaging (DTI) and resting-state functional MRI (fMRI). In addition, subjects underwent clinical examinations and cognitive assessments. We included 18 a priori predictors from neuroimaging, clinical and cognitive measures in the initial model. We used 10-fold cross-validation to learn the importance of each modality, train and finally test the model performance. The mean accuracy in differentiating between MS and NMO was 88%, where visible white matter lesion load, normal appearing white matter (DTI) and functional connectivity had the most important contributions to the final classification. In a multi-class classification problem we distinguished between all of 3 groups (MS, NMO and healthy controls) with an average accuracy of 84%. In this classification, visible white matter lesion load, functional connectivity, and cognitive scores were the 3 most important modalities. Our work provides preliminary evidence that computational tools can be used to help make an objective differential diagnosis of NMO and MS.

  19. Classification algorithms with multi-modal data fusion could accurately distinguish neuromyelitis optica from multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Arman Eshaghi

    2015-01-01

    Full Text Available Neuromyelitis optica (NMO exhibits substantial similarities to multiple sclerosis (MS in clinical manifestations and imaging results and has long been considered a variant of MS. With the advent of a specific biomarker in NMO, known as anti-aquaporin 4, this assumption has changed; however, the differential diagnosis remains challenging and it is still not clear whether a combination of neuroimaging and clinical data could be used to aid clinical decision-making. Computer-aided diagnosis is a rapidly evolving process that holds great promise to facilitate objective differential diagnoses of disorders that show similar presentations. In this study, we aimed to use a powerful method for multi-modal data fusion, known as a multi-kernel learning and performed automatic diagnosis of subjects. We included 30 patients with NMO, 25 patients with MS and 35 healthy volunteers and performed multi-modal imaging with T1-weighted high resolution scans, diffusion tensor imaging (DTI and resting-state functional MRI (fMRI. In addition, subjects underwent clinical examinations and cognitive assessments. We included 18 a priori predictors from neuroimaging, clinical and cognitive measures in the initial model. We used 10-fold cross-validation to learn the importance of each modality, train and finally test the model performance. The mean accuracy in differentiating between MS and NMO was 88%, where visible white matter lesion load, normal appearing white matter (DTI and functional connectivity had the most important contributions to the final classification. In a multi-class classification problem we distinguished between all of 3 groups (MS, NMO and healthy controls with an average accuracy of 84%. In this classification, visible white matter lesion load, functional connectivity, and cognitive scores were the 3 most important modalities. Our work provides preliminary evidence that computational tools can be used to help make an objective differential diagnosis

  20. Measurement of Healthy Adult Kidney's Range of Motion by Cine-MRI%Cine-MRI测量健康成年人肾脏运动幅度

    Institute of Scientific and Technical Information of China (English)

    范文骏; 龙淼淼; 沈文; 倪红艳; 黄黎香

    2013-01-01

    目的 通过电影磁共振成像(Cine-MRI)技术观察健康成年人平静规律呼吸状态下双肾运动幅度.资料与方法 选取57名健康成年志愿者(男28名,女29名),于平静规律呼吸状态下进行与双肾长轴平行的斜冠状面Cine-MRI检查,测量一次完整呼吸过程中双肾下极运动幅度,比较双侧肾脏及不同性别间肾脏运动幅度的差异.结果 Cine-MRI测得健康成年人平静规律呼吸状态下右肾运动幅度为5.6~16.5 mm,平均(9.5±2.1) mm;左肾运动幅度为4.5~13.9 mm,平均(8.1±2.0) mm;双侧肾脏运动幅度比较,差异有统计学意义(t=9.30,P<0.05);男性左、右侧肾脏运动幅度分别为(8.7±2.0) mm和(10.3±2.2) mm,均大于女性对应侧肾脏运动幅度[分别为(7.5±1.8) mm和(8.8±1.7) mm],差异有统计学意义(t=2.82、4.41,P<0.05).结论 平静规律呼吸状态下斜冠状面上右肾运动幅度大于左肾,在进行功能磁共振成像时宜选用左肾数据作为参照标准,尤其是当受检者为男性时.%Purpose To observe the healthy adult kidneys' range of motion in the calm regular breathing state through Cine-MRI.Materials and Methods Cine-MRI was applied to 57 healthy adult volunteers (28 male,29 female) on oblique coronal plane parallel to the long axis of the kidneys in a state of calm regular breathing.The range of motion of lower renal pole was measured in the process of a full breathing,and was compared between the double kidneys and between different gender.Results The range of motion of the right and left kidney of healthy adult was from 5.6 mm to 16.5 mm,mean (9.5 ±2.1) mm; and 4.5mm to 13.9 mm,mean (8.1 ±2.0) mm,respectively,and it was demonstrated significant difference between bilateral kidneys (t=9.30,P<0.05).The range of motion of left and right kidney of the male subjects were (8.7± 2.0) mm and (10.3 ± 2.2) mm,which were larger than those of female subjects [(7.5±1.8) mm and (8.8± 1.7) mm],and it revealed the significant

  1. MRI features of tuberculosis of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Sanghvi, Darshana A.; Iyer, Veena R.; Deshmukh, Tejaswini; Hoskote, Sumedh S. [Seth GS Medical College and KEM Hospital, Department of Radiology, Mumbai (India)

    2009-03-15

    The objective of this study was to describe the magnetic resonance imaging (MRI) features of tuberculosis (TB) of the knee joint. The MRI features in 15 patients with TB of the knee, as confirmed by histology of the biopsied joint synovium, were reviewed retrospectively. The images were assessed for intra-articular and peri-articular abnormalities. All patients had florid synovial proliferation. The proliferating synovium showed intermediate to low T2 signal intensity. In the patients who were administered intravenous contrast, the hypertrophic synovium was intensely enhancing. Marrow edema (n = 9), osteomyelitis (n = 4), cortical erosions (n = 5), myositis (n = 6), cellulitis (n = 2), abscesses (n = 3), and skin ulceration/sinus formation (n = 2) were seen in the adjacent bone and soft tissue. Synovial proliferation associated with tuberculous arthritis is typically hypointense on T2-weighted images. This appearance, in conjunction with other peri-articular MRI features described, can help in distinguishing TB arthritis from other proliferating synovial arthropathies. (orig.)

  2. A comparison of MRI criteria for diagnosing pediatric ADEM and MS

    NARCIS (Netherlands)

    Ketelslegers, I. A.; Neuteboom, R. F.; Boon, M.; Catsman-Berrevoets, C. E.; Hintzen, R. Q.

    2010-01-01

    Background: Brain MRI is a useful tool for diagnosing inflammatory demyelinating disorders in children. However, it remains unclear which are the most reliable criteria for distinguishing multiple sclerosis (MS) from monophasic disorders such as acute disseminated encephalomyelitis (ADEM). We theref

  3. A comparison of MRI criteria for diagnosing pediatric ADEM and MS.

    NARCIS (Netherlands)

    Ketelslegers, I.A.; Neuteboom, R.F.; Boon, M.; Catsman-Berrevoets, C.E.; Hintzen, R.Q.

    2010-01-01

    BACKGROUND: Brain MRI is a useful tool for diagnosing inflammatory demyelinating disorders in children. However, it remains unclear which are the most reliable criteria for distinguishing multiple sclerosis (MS) from monophasic disorders such as acute disseminated encephalomyelitis (ADEM). We theref

  4. MRI of the lungs in children

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, Wolfgang [Paediatric Radiology in the Department of Diagnostic and Interventional Radiology, University Hospital Leipzig (Germany)], E-mail: wolfgang.hirsch@medizin.uni-leipzig.de; Sorge, Ina; Krohmer, Svetlana; Weber, Dana [Paediatric Radiology in the Department of Diagnostic and Interventional Radiology, University Hospital Leipzig (Germany); Meier, Konstanze [Department of Paediatrics, University Hospital Leipzig (Germany); Till, Holger [Department of Paediatric Surgery, University Hospital Leipzig (Germany)

    2008-11-15

    Lung diseases of children often need diagnostic imaging beyond X-ray. Although CT is considered the gold standard of lung imaging, MRI is sufficient to answer most of the questions raised. After all, the exposure to radiation caused by one CT examination corresponds to approximately the effective dose of 200 chest radiographs. What is MRI's potential in the lung today? In diseases with alveolar pathology, cardiac- and respiratory-triggered MRI examinations are roughly equivalent to CT examinations. Distinct interstitial processes are easily diagnosable using MRI. Early interstitial processes may be missed by MRI, but conventional plain films fail to recognize them just as often. For identification of lung metastases, CT is still used as the initial diagnostic measure. Subsequent therapy monitoring may then be carried out with the help of MRI. Small bullae and pulmonary emphysema at present pose a problem to MRI. On the other hand, MRI is reliable for follow-up examinations in inflammatory diseases or for imaging of complications, and the increased use of lung MRI as an alternative to chest CT may contribute immensely to reducing radiation exposure in children.

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) ... ray, CT and ultrasound. top of page How is the procedure performed? MRI examinations may be performed ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses ... of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  7. Distinguishing patients with Parkinson's disease subtypes from normal controls based on functional network regional efficiencies.

    Directory of Open Access Journals (Sweden)

    Delong Zhang

    Full Text Available Many studies have demonstrated that the pathophysiology and clinical symptoms of Parkinson's disease (PD are inhomogeneous. However, the symptom-specific intrinsic neural activities underlying the PD subtypes are still not well understood. Here, 15 tremor-dominant PD patients, 10 non-tremor-dominant PD patients, and 20 matched normal controls (NCs were recruited and underwent resting-state functional magnetic resonance imaging (fMRI. Functional brain networks were constructed based on randomly generated anatomical templates with and without the cerebellum. The regional network efficiencies (i.e., the local and global efficiencies were further measured and used to distinguish subgroups of PD patients (i.e., with tremor-dominant PD and non-tremor-dominant PD from the NCs using linear discriminant analysis. The results demonstrate that the subtype-specific functional networks were small-world-organized and that the network regional efficiency could discriminate among the individual PD subgroups and the NCs. Brain regions involved in distinguishing between the study groups included the basal ganglia (i.e., the caudate and putamen, limbic regions (i.e., the hippocampus and thalamus, the cerebellum, and other cerebral regions (e.g., the insula, cingulum, and calcarine sulcus. In particular, the performances of the regional local efficiency in the functional network were better than those of the global efficiency, and the performances of global efficiency were dependent on the inclusion of the cerebellum in the analysis. These findings provide new evidence for the neurological basis of differences between PD subtypes and suggest that the cerebellum may play different roles in the pathologies of different PD subtypes. The present study demonstrated the power of the combination of graph-based network analysis and discrimination analysis in elucidating the neural basis of different PD subtypes.

  8. Abdominal MRI scan

    Science.gov (United States)

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ...

  9. MRI of the Chest

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    Full Text Available ... about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want ... projectiles within the MRI scanner room and may cause you and/or others nearby harm. These items ...

  10. MRI of the Chest

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    Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ... tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms that ...

  11. MRI of the Chest

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    Full Text Available ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ... might be obscured by bone with other imaging methods. The contrast material used in MRI exams is ...

  12. MRI of the Chest

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... with claustrophobia. Newer open MRI units provide very high quality images for many types of exams. Older ...

  13. MRI of the Chest

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    Full Text Available ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ... the limitations of MRI of the Chest? High-quality images are assured only if you are able ...

  14. MRI of the Chest

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    Full Text Available ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ... might be obscured by bone with other imaging methods. The contrast material used in MRI exams is ...

  15. MRI of the Chest

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    Full Text Available ... have this exam in the first trimester of pregnancy unless the potential benefit from the MRI exam ... See the Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

  16. MRI of the Chest

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging technique that ... risking the side effects of conventional (catheter) angiography . Risks The MRI examination poses almost no risk to ...

  17. MRI of the Chest

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    Full Text Available ... or potentially pose a risk, depending on their nature and the strength of the MRI magnet. Many ... of the body being studied. If a contrast material will be used in the MRI exam, a ...

  18. MRI of the Chest

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    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven valuable in ...

  19. MRI of the Chest

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    Full Text Available ... MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ...

  20. MRI of the Chest

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    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of ... Although there is no reason to believe that magnetic resonance imaging harms the fetus, pregnant women usually are ...

  1. MRI of the Chest

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    Full Text Available ... claustrophobia. Newer open MRI units provide very high quality images for many types of exams; however, older ... MRI units may not provide this same image quality. Certain types of exams cannot be performed using ...

  2. MRI of the Chest

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    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven valuable in ...

  3. MRI of the Chest

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  4. MRI of the Chest

    Science.gov (United States)

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  5. Compressed sensing for body MRI.

    Science.gov (United States)

    Feng, Li; Benkert, Thomas; Block, Kai Tobias; Sodickson, Daniel K; Otazo, Ricardo; Chandarana, Hersh

    2017-04-01

    The introduction of compressed sensing for increasing imaging speed in magnetic resonance imaging (MRI) has raised significant interest among researchers and clinicians, and has initiated a large body of research across multiple clinical applications over the last decade. Compressed sensing aims to reconstruct unaliased images from fewer measurements than are traditionally required in MRI by exploiting image compressibility or sparsity. Moreover, appropriate combinations of compressed sensing with previously introduced fast imaging approaches, such as parallel imaging, have demonstrated further improved performance. The advent of compressed sensing marks the prelude to a new era of rapid MRI, where the focus of data acquisition has changed from sampling based on the nominal number of voxels and/or frames to sampling based on the desired information content. This article presents a brief overview of the application of compressed sensing techniques in body MRI, where imaging speed is crucial due to the presence of respiratory motion along with stringent constraints on spatial and temporal resolution. The first section provides an overview of the basic compressed sensing methodology, including the notion of sparsity, incoherence, and nonlinear reconstruction. The second section reviews state-of-the-art compressed sensing techniques that have been demonstrated for various clinical body MRI applications. In the final section, the article discusses current challenges and future opportunities. 5 J. Magn. Reson. Imaging 2017;45:966-987. © 2016 International Society for Magnetic Resonance in Medicine.

  6. MRI in acute poliomyelitis

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, L. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Dagan, O. [The Intensive Care Unit, The Schneider Children`s Medical Centre of Israel, Beilinson Medical Campus, Petah Tiqva (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Grunebaum, M. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    1996-05-01

    MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig.

  7. MRI of the Chest

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    Full Text Available ... field of the MRI unit, metal and electronic items are not allowed in the exam room. In addition to affecting the MRI images, ... damaged pins, hairpins, metal zippers and similar metallic items, which can distort ... In most cases, an MRI exam is safe for patients with metal implants, except ...

  8. fMRI Neuroinformatics

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup; Christensen, Mark Schram; Madsen, Kristoffer M.

    2006-01-01

    Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction...

  9. Distinguishing benign from malignant main duct intraductal papillary mucinous tumors of the pancreas by CT and MRI%CT和MRI对主胰管型胰腺导管内乳头状黏液瘤良恶性鉴别的价值

    Institute of Scientific and Technical Information of China (English)

    边云; 李骁; 陈炜; 高振坡; 王莉; 陆建平

    2015-01-01

    Objective To evaluate the value of imaging studies in diagnosis and differentiating malignant from benign main duct intraductal papillary mucinous neoplasms (MD-IPMNs).Methods The imaging studies of a total of 31 patients with MD-IPMNs confirmed by pathology after surgery was retrospectively reviewed.All patients underwent either CT,MR or MRCP.Two radiologists observed the lesions' imaging feature,and then the lesions was scored,and the differentiation between malignant and benign was made.The Bland Altman method was used for evaluation of inter-observer agreement.The score of the lesions was compared with the pathological results.Finally,a ROC curve was used to calculate AUC,and to evaluate the role of the maximum diameter of the main pancreatic duct (MPD) obtained by imaging studies in differentiation of malignant and benign IPMNs,and to determine the best cut-off point,and sensitivity,specificity.Results Histological analysis revealed low grade dysplasia in 13 patients,middle grade dysplasia in 6 and high grade dysplasia in 5,and adenocarcinoma in 7.Imaging studies suggested benign lesions in 16,malignant lesions in 10 patients and disdiagnosis in 5.The inter-observer agreement on major imaging features was good.The maximum diameter of the MPD was clinically meaningful for distinguishing malignant from benign lesions,and the AUC was 83.8%,and the best cut-off value was 14.8 mm,the sensitivity and specificity was 66.7% and 100%.The presence of wall nodules could be an imaging feature for distinguishing malignant from benign lesions,but the size of nodules,location of nodules within pancreatic duct,the atrophy of pancreatic parenchyma,and dilated bile duct was not useful for differentiation.Conclusions The imaging studies are sensitive for diagnosis and differentiation between malignant and benign MD-IPMNs,and it is of clinical value for preoperative diagnosis and follow up.%目的 探讨影像学检查对主胰管型胰腺导管内乳头状瘤(MD-IPMN)诊

  10. MRI、超声及钼靶在乳腺肿块大小测量中的比较%A Comparative Analysis of MRI, Ultrasonography and Molybdenum Target Mammography in the Measurement of Breast Lump Size

    Institute of Scientific and Technical Information of China (English)

    安静; 夏玉军

    2016-01-01

    Objective To comparatively analyze the accuracy of MRI, ultrasound and mammography in the measurement of lump size in patients with breast cancer. Methods 51 cases of breast tumor patients (53 lesions) who underwent diagnosis and treatment for breast tumors from January 2014 to June 2014 in our hospital were selected as research objects. All the selected patients underwent preoperative mammography, ultrasound, and MRI examination to measure the size of breast lumps. The corresponding data was recorded and compared with postoperative pathological results. The accuracy of the three methods in determining the lump size was compared. Results The difference between the maximum cross-sectional diameter of breast lumps obtained from mammography, ultrasound, and MRI measurements and the results obtained by actual measurement of pathological specimens was≤1 cm in 10 cases ( 27.8%), 20 cases ( 55.6%) , and 24 cases ( 66.7%) respectively. Conclusion The accuracy of MRI in the measurement of breast lump size was higher than the accuracy of ultrasound and mammography. MRI is a realiable examination method in the preoperative assessment of breast tumor size.%目的:对比分析MRI、超声及钼靶测量乳腺肿块大小的准确性。方法选取2014年1月~2014年6月在本院就诊的51例乳腺肿物患者(53个病灶)为研究对象,所有患者于术前均通过钼靶、超声及MRI检查测量了肿块大小,记录相应数据,并与术后病理结果进行对比,比较3种方法测量肿块大小的准确性。结果钼靶、超声、MRI测得的乳腺肿块横截面最大径与病理标本的实际测量值差值≤1 cm者分别有10例(27.8%)、20例(55.6%)、24例(66.7%)。结论MRI检查测量乳腺肿块大小的准确性高于钼靶和超声检查,是术前准确评估乳腺肿块大小的可靠检查手段。

  11. Atrophy of medial temporal lobes on MRI in "probable" Alzheimer's disease and normal ageing: diagnostic value and neuropsychological correlates.

    Science.gov (United States)

    Scheltens, P; Leys, D; Barkhof, F; Huglo, D; Weinstein, H C; Vermersch, P; Kuiper, M; Steinling, M; Wolters, E C; Valk, J

    1992-10-01

    Magnetic resonance imaging (MRI) has shown a great reduction in medial temporal lobe and hippocampal volume of patients with Alzheimer's disease as compared to controls. Quantitative volumetric measurements are not yet available for routine clinical use. We investigated whether visual assessment of medial temporal lobe atrophy (MTA) on plain MRI films could distinguish patients with Alzheimer's disease (n = 21) from age matched controls (n = 21). The degree of MTA was ascertained with a ranking procedure and validated by linear measurements of the medial temporal lobe including the hippocampal formation and surrounding spaces occupied by cerebrospinal fluid. Patients with Alzheimer's disease showed a significantly higher degree of subjectively assessed MTA than controls (p = 0.0005). Linear measurements correlated highly with subjective assessment of MTA and also showed significant differences between groups. Ventricular indices did not differ significantly between groups. In Alzheimer's disease patients the degree of MTA correlated significantly with scores on the mini-mental state examination and memory tests, but poorly with mental speed tests. This study shows that MTA may be assessed quickly and easily with plain MRI films. MTA shown on MRI strongly supports the clinical diagnosis of Alzheimer's disease, is related to memory function, and seems to occur earlier in the disease process than does generalised brain atrophy.

  12. 3.0 T MRI上深筋膜完整性对于下肢软组织肿瘤良、恶性鉴别的价值%The diagnostic value of delineating deep fascia in distinguishing between benign and malignant soft-tissue tumors in lower limbs using 3.0 T MRI

    Institute of Scientific and Technical Information of China (English)

    刘莉; 欧阳汉; 吴宁

    2010-01-01

    目的 分析3.0 T MRI上深筋膜形态改变对于鉴别下肢软组织肿瘤良、恶性的价值.方法 回顾分析40例患者共41个经病理证实的下肢软组织肿瘤的3.0 T MRI表现.将肿瘤按主体与深筋膜的关系分为位于皮下浅层深筋膜外侧、深筋膜内侧、筋膜鞘间隙内、肌肉内的4组肿瘤,分析肿瘤与深筋膜的关系及深筋膜的形态学改变.将深筋膜外侧及内侧组肿瘤归为浅在肿瘤,筋膜鞘间隙及肌肉内肿瘤归为深部肿瘤,分别对其筋膜完整及筋膜破坏肿瘤的最大径进行Mann-Whitney U检验.结果 深筋膜外侧肿瘤7个,深筋膜内侧肿瘤8个,筋膜鞘间隙内肿瘤10个,肌肉内肿瘤16个.良性肿瘤16个,MRI显示深筋膜均完整,筋膜鞘间脂肪间隙存在;恶性肿瘤25个,其中23个见深筋膜破坏征象,包括筋膜中断处被肿瘤取代,肿瘤穿透筋膜生长;筋膜鞘间结构破坏,肌肉层次模糊,2例恶性肿瘤深筋膜完整.浅在肿瘤中,深筋膜完整者及破坏者肿瘤最大径的中位数±四分位数区间分别为(5.0±3.8)cm和(5.7±6.9)cm,两者差异无统计学意义(T=47.5,P>0.05).深部肿瘤中,深筋膜完整者及破坏者最大径的中位数±四分位数区间分别为(4.6±1.9)cm和(13.6±6.5)cm,两者差异有统计学意义(T=62.5,P0.05). In deeper lesions [(3) (4)] the maximum size were (4.6±1.9) cm of those had intact deep fascia, and (13.6±6.5) cm of those had destruction signs (T= 62.5, P <0.01). Distinguish malignant from benign lesions on the signs of destructed deep fascia, the sensitivity, specificity and accuracy were 92.0% (23/25), 100% (16/16), and 95. 1% (39/,41), respectively. Conclusions Tumor involvements and disruption of the deep fascial structures visualized by 3.0 T MR imaging may be of utility in differentiating malignant from benign soft-tissue tumors.

  13. SU-F-303-13: Initial Evaluation of Four Dimensional Diffusion- Weighted MRI (4D-DWI) and Its Effect On Apparent Diffusion Coefficient (ADC) Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y [Duke University Medical Physics Program (United States); Yin, F; Czito, B; Bashir, M; Palta, M; Cai, J [Duke University Medical Center, Durham, NC (United States); Zhong, X; Dale, B [Siemens Healthcare, Durham, NC (United States)

    2015-06-15

    Purpose: Diffusion-weighted imaging(DWI) has been shown to have superior tumor-to-tissue contrast for cancer detection.This study aims at developing and evaluating a four dimensional DWI(4D-DWI) technique using retrospective sorting method for imaging respiratory motion for radiotherapy planning,and evaluate its effect on Apparent Diffusion Coefficient(ADC) measurement. Materials/Methods: Image acquisition was performed by repeatedly imaging a volume of interest using a multi-slice single-shot 2D-DWI sequence in the axial planes and cine MRI(served as reference) using FIESTA sequence.Each 2D-DWI image were acquired in xyz-diffusion-directions with a high b-value(b=500s/mm2).The respiratory motion was simultaneously recorded using bellows.Retrospective sorting was applied in each direction to reconstruct 4D-DWI.The technique was evaluated using a computer simulated 4D-digital human phantom(XCAT),a motion phantom and a healthy volunteer under an IRB-approved study.Motion trajectories of regions-of-interests(ROI) were extracted from 4D-DWI and compared with reference.The mean motion trajectory amplitude differences(D) between the two was calculated.To quantitatively analyze the motion artifacts,XCAT were controlled to simulate regular motion and the motions of 10 liver cancer patients.4D-DWI,free-breathing DWI(FB- DWI) were reconstructed.Tumor volume difference(VD) of each phase of 4D-DWI and FB-DWI from the input static tumor were calculated.Furthermore, ADC was measured for each phase of 4D-DWI and FB-DWI data,and mean tumor ADC values(M-ADC) were calculated.Mean M-ADC over all 4D-DWI phases was compared with M-ADC calculated from FB-DWI. Results: 4D-DWI of XCAT,the motion phantom and the healthy volunteer demonstrated the respiratory motion clearly.ROI D values were 1.9mm,1.7mm and 2.0mm,respectively.For motion artifacts analysis,XCAT 4D-DWI images show much less motion artifacts compare to FB-DWI.Mean VD for 4D-WDI and FB-DWI were 8.5±1.4% and 108±15

  14. Superresolution improves MRI cortical segmentation with FACE

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Manjón, José V.; Coupé, Pierrick

    Brain cortical surface extraction f