Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

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Muhle, C. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Brossmann, J. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Melchert, U.H. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Schroeder, C. [Radiologische Abt., Universitaets-Kinderklinik, Christian-Albrechts-Universitaet, Kiel (Germany); Boer, R. de [Philips Medical Systems, Best (Netherlands); Spielmann, R.P. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Heller, M. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany)

1995-12-31

To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

International Nuclear Information System (INIS)

Muhle, C.; Brossmann, J.; Melchert, U.H.; Schroeder, C.; Boer, R. de; Spielmann, R.P.; Heller, M.

1995-01-01

To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

In situ targeted MRI detection of Helicobacter pylori with stable magnetic graphitic nanocapsules

Science.gov (United States)

Li, Yunjie; Hu, Xiaoxiao; Ding, Ding; Zou, Yuxiu; Xu, Yiting; Wang, Xuewei; Zhang, Yin; Chen, Long; Chen, Zhuo; Tan, Weihong

2017-06-01

Helicobacter pylori infection is implicated in the aetiology of many diseases. Despite numerous studies, a painless, fast and direct method for the in situ detection of H. pylori remains a challenge, mainly due to the strong acidic/enzymatic environment of the gastric mucosa. Herein, we report the use of stable magnetic graphitic nanocapsules (MGNs), for in situ targeted magnetic resonance imaging (MRI) detection of H. pylori. Several layers of graphene as the shell effectively protect the magnetic core from corrosion while retaining the superior contrast effect for MRI in the gastric environment. Boronic-polyethylene glycol molecules were synthesized and modified on the MGN surface for targeted MRI detection. In a mouse model of H. pylori-induced infection, H. pylori was specifically detected through both T2-weighted MR imaging and Raman gastric mucosa imaging using functionalized MGNs. These results indicated that enhancement of MRI using MGNs may be a promising diagnostic and bioimaging platform for very harsh conditions.

Bayesian Inference for Functional Dynamics Exploring in fMRI Data

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Xuan Guo

2016-01-01

Full Text Available This paper aims to review state-of-the-art Bayesian-inference-based methods applied to functional magnetic resonance imaging (fMRI data. Particularly, we focus on one specific long-standing challenge in the computational modeling of fMRI datasets: how to effectively explore typical functional interactions from fMRI time series and the corresponding boundaries of temporal segments. Bayesian inference is a method of statistical inference which has been shown to be a powerful tool to encode dependence relationships among the variables with uncertainty. Here we provide an introduction to a group of Bayesian-inference-based methods for fMRI data analysis, which were designed to detect magnitude or functional connectivity change points and to infer their functional interaction patterns based on corresponding temporal boundaries. We also provide a comparison of three popular Bayesian models, that is, Bayesian Magnitude Change Point Model (BMCPM, Bayesian Connectivity Change Point Model (BCCPM, and Dynamic Bayesian Variable Partition Model (DBVPM, and give a summary of their applications. We envision that more delicate Bayesian inference models will be emerging and play increasingly important roles in modeling brain functions in the years to come.

Cognitive function and MRI findings in very low birth weight infants

International Nuclear Information System (INIS)

Imamura, Atsuko; Takagishi, Yuka; Takada, Satoru; Uetani, Yoshiyuki; Nakamura, Toru; Nakamura, Hajime; Inagaki, Yuko.

1996-01-01

Twenty-two very low birth weight infants at preschool ages of 5-6 years were studied to clarify the correlation between cognitive function and MRI findings. Cognitive function was evaluated by the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Frostig developmental test of visual perception. Ventricular enlargement, assessed by the bioccipital index (B.I.) measured on MRI, was correlated to cognitive disorders. Children with periventricular high intensity areas (T 2 -weighted images) extending from the posterior periventricular region to the parietal lobe tend to highly suffer from cerebral palsy and visuoperceptual impairment. These results indicate that the disorders of cognitive function in very low birth weight infants were caused by a damage of association fibers in periventricular areas which was detectable by MRI. (author)

Application of functional MRI in breast diseases

International Nuclear Information System (INIS)

Feng Yun; Liu Shiyuan; Wang Chenguang; Tao Xiaofeng; Wang Jinlin; Wang Jian

2007-01-01

Objective: To investigate the value of functional MRI in the diagnosis and differential diagnosis of breast diseases. Methods: Sixty-five patients with 68 lesions were enrolled in this study. Conventional T 1 WI and T 2 WI scan, dynamic contrast enhanced MRI, diffusion weighted imaging and 1 H single voxel MR spectroscopy were performed consequently. All lesions were verified by pathology, including 4 cases of breast adenosis, 22 fibroadenomas, 2 chronic inflammations, 3 cysts, 33 infitrating ductal carcinomas, 1 intraductal carcinoma and 3 cystosarcoma phyllodes tumors. Morphological features, maximum enhancement ratio, time-intensity curve, apparent diffusion coefficient and Choline peak were analyzed. Results: The detection rates of T 1 WI and T 2 WI were 14.7% (n=10) and 51.5% (n=35). The sensitivity, specificity, accuracy of dynamic contrast enhanced MRI for the malignant tumor were 94. 6%, 71.4% and 76.5% respectively. Retrospective study showed that diffusion weighted imaging, with the b value from 800 s/mm 2 to 1000 s/mm 2 , could be used to differentiate various types of breast lesions. 1 H signal voxel spectroscopy had a sensitivity of 51.4%, specificity of 82.6%, and accuracy of 67.6% for the malignent. The sensitivity, specificity and accuracy could reach 97.3%, 90.0% and 92.6% respectively by combining conventional scan, dynamic contrast enhanced MRI and MR spectroscopy. Conclusion: Functional MRI, with high sensitivity, specificity and accuracy, can be used widely in the diagnosis of malignant breast lesions. (authors)

“Awake” intraoperative functional MRI (ai-fMRI) for mapping the eloquent cortex: Is it possible in awake craniotomy?☆

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Lu, Jun-Feng; Zhang, Han; Wu, Jin-Song; Yao, Cheng-Jun; Zhuang, Dong-Xiao; Qiu, Tian-Ming; Jia, Wen-Bin; Mao, Ying; Zhou, Liang-Fu

2012-01-01

As a promising noninvasive imaging technique, functional MRI (fMRI) has been extensively adopted as a functional localization procedure for surgical planning. However, the information provided by preoperative fMRI (pre-fMRI) is hampered by the brain deformation that is secondary to surgical procedures. Therefore, intraoperative fMRI (i-fMRI) becomes a potential alternative that can compensate for brain shifts by updating the functional localization information during craniotomy. However, previous i-fMRI studies required that patients be under general anesthesia, preventing the wider application of such a technique as the patients cannot perform tasks unless they are awake. In this study, we propose a new technique that combines awake surgery and i-fMRI, named “awake” i-fMRI (ai-fMRI). We introduced ai-fMRI to the real-time localization of sensorimotor areas during awake craniotomy in seven patients. The results showed that ai-fMRI could successfully detect activations in the bilateral primary sensorimotor areas and supplementary motor areas for all patients, indicating the feasibility of this technique in eloquent area localization. The reliability of ai-fMRI was further validated using intraoperative stimulation mapping (ISM) in two of the seven patients. Comparisons between the pre-fMRI-derived localization result and the ai-fMRI derived result showed that the former was subject to a heavy brain shift and led to incorrect localization, while the latter solved that problem. Additionally, the approaches for the acquisition and processing of the ai-fMRI data were fully illustrated and described. Some practical issues on employing ai-fMRI in awake craniotomy were systemically discussed, and guidelines were provided. PMID:24179766

Normal pancreatic exocrine function does not exclude MRI/MRCP chronic pancreatitis findings.

Science.gov (United States)

Alkaade, Samer; Cem Balci, Numan; Momtahen, Amir Javad; Burton, Frank

2008-09-01

Abnormal pancreatic function tests have been reported to precede the imaging findings of chronic pancreatitis. Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) is increasingly accepted as the primary imaging modality for the detection of structural changes of early mild chronic pancreatitis. The aim of this study was to evaluate MRI/MRCP findings in patients with symptoms consistent with chronic pancreatitis who have normal Secretin Endoscopic Pancreatic Function test. A retrospective study of 32 patients referred for evaluation of chronic abdominal pain consistent with chronic pancreatitis and reported normal standard abdominal imaging (ultrasound, computed tomography, or MRI). All patients underwent Secretin Endoscopic Pancreatic Function testing and pancreatic MRI/MRCP at our institution. We reviewed the MRI/MRCP images in patients who had normal Secretin Endoscopic Pancreatic Function testing. MRI/MRCP images were assessed for pancreatic duct morphology, gland size, parenchymal signal and morphology, and arterial contrast enhancement. Of the 32 patients, 23 had normal Secretin Endoscopic Pancreatic Function testing, and 8 of them had mild to marked spectrum of abnormal MRI/MRCP findings that were predominantly focal. Frequencies of the findings were as follows: pancreatic duct stricture (n=3), pancreatic duct dilatation (n=3), side branch ectasia (n=4), atrophy (n=5), decreased arterial enhancement (n=5), decreased parenchymal signal (n=1), and cavity formation (n=1). The remaining15 patients had normal pancreatic structure on MRI/MRCP. Normal pancreatic function testing cannot exclude abnormal MRI/MRCP especially focal findings of chronic pancreatitis. Further studies needed to verify significance of these findings and establish MRI/MRCP imaging criteria for the diagnosis of chronic pancreatitis.

Cognitive function and MRI findings in very low birth weight infants

Energy Technology Data Exchange (ETDEWEB)

Imamura, Atsuko; Takagishi, Yuka; Takada, Satoru; Uetani, Yoshiyuki; Nakamura, Toru; Nakamura, Hajime [Kobe Univ. (Japan). School of Medicine; Inagaki, Yuko

1996-07-01

Twenty-two very low birth weight infants at preschool ages of 5-6 years were studied to clarify the correlation between cognitive function and MRI findings. Cognitive function was evaluated by the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Frostig developmental test of visual perception. Ventricular enlargement, assessed by the bioccipital index (B.I.) measured on MRI, was correlated to cognitive disorders. Children with periventricular high intensity areas (T{sub 2}-weighted images) extending from the posterior periventricular region to the parietal lobe tend to highly suffer from cerebral palsy and visuoperceptual impairment. These results indicate that the disorders of cognitive function in very low birth weight infants were caused by a damage of association fibers in periventricular areas which was detectable by MRI. (author)

Effects of Field-Map Distortion Correction on Resting State Functional Connectivity MRI

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Hiroki Togo

2017-12-01

Full Text Available Magnetic field inhomogeneities cause geometric distortions of echo planar images used for functional magnetic resonance imaging (fMRI. To reduce this problem, distortion correction (DC with field map is widely used for both task and resting-state fMRI (rs-fMRI. Although DC with field map has been reported to improve the quality of task fMRI, little is known about its effects on rs-fMRI. Here, we tested the influence of field-map DC on rs-fMRI results using two rs-fMRI datasets derived from 40 healthy subjects: one with DC (DC+ and the other without correction (DC−. Independent component analysis followed by the dual regression approach was used for evaluation of resting-state functional connectivity networks (RSN. We also obtained the ratio of low-frequency to high-frequency signal power (0.01–0.1 Hz and above 0.1 Hz, respectively; LFHF ratio to assess the quality of rs-fMRI signals. For comparison of RSN between DC+ and DC− datasets, the default mode network showed more robust functional connectivity in the DC+ dataset than the DC− dataset. Basal ganglia RSN showed some decreases in functional connectivity primarily in white matter, indicating imperfect registration/normalization without DC. Supplementary seed-based and simulation analyses supported the utility of DC. Furthermore, we found a higher LFHF ratio after field map correction in the anterior cingulate cortex, posterior cingulate cortex, ventral striatum, and cerebellum. In conclusion, field map DC improved detection of functional connectivity derived from low-frequency rs-fMRI signals. We encourage researchers to include a DC step in the preprocessing pipeline of rs-fMRI analysis.

Clinical application of functional MRI

International Nuclear Information System (INIS)

Taniwaki, Takayuki

2010-01-01

Described is the present state of clinical application of fMRI in the preoperative assessment of brain tumors, and plasticity in and pathophysiology of central diseases. For the tumor resection, fMRI is useful for risk assessment of postoperative nerve dysfunction, for selection of the patient rather suitable for brain mapping at the invasive surgery than at the pre-operation and for guidance of the operation itself. Preoperative fMRI alone can neither distinguish the regions of the primary and secondary functions nor exhibit the relation between the tumor and white matter fibers but there are compensatory means for these drawbacks. Benefit of preoperative fMRI has not yet been based on the evidence on double blind trials. Combination of fMRI imaging and electroencephalography (EEG) finding has shown that, in generalized epilepsy, extensive and stimulated activation occurs in both frontal/occipital regions and in thalamus area, respectively, and that the concomitant lowered activities are conceivably the reflection of burst discharge in normal brain functions. Plasticity in the human brain has been demonstrated by fMRI in cerebral vascular diseases, multiple sclerosis and amyotrophic lateral sclerosis. Pathogenesis of Parkinson disease and depression has been better understood by fMRI investigations revealing regions with elevated and reduced activities. Studies of attention deficit hyperactivity disorder have shown similar change of activities with functional reductions of the right dorsolateral frontal anterior area and of dorsal frontal cingulate gyrus, together with stimulated wider regions to given tasks. As above, fMRI has greatly contributed to our understanding of diseases of central nervous system and is to be expected to expand wider in this field. (T.T.)

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...... consistent data throughout the course of a study, and consistent stability across time and sites is needed to allow data from different time periods or acquisition sites to be optimally integrated....

Comparision the value of detecting myocardial viability between low dose dobutamine stress MRI and echocardiography

International Nuclear Information System (INIS)

He Yi; Zhang Zhaoqi; Yu Wei; Miao Cuilian; Zhao Yike; Yan Zixu

2006-01-01

Objective: To Compare the diagnostic value between low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI in detecting myocardial viability of chronic myocardial infarction. Methods: Rest and low dose dobutamine (5, 10 μg·kg -1 ·min -1 ) stress transthrotic echocardiography and cine-MRI were performed in 30 patients with chronic myocardial infarction. 24 patients underwent successful revascularization and 10 of them underwent another rest cine-MRI study to assess segmental myocardial functional recovery. Left ventricular were divided into 16 segments, the criteria of viability in different techniques is: MRI: dobutamine induced systolic wall thickening was ≥2 mm in akinetic or diskinetic segments at rest; Echocardiography: wall motion score reduced at least 1 after dobutamine stress in akinetic or' diskinetic segments at rest. Results: One hundren and eight segments showed wall motion abnormalities of 30 patients, 65 and 56 segments shows positive reaction, 43 and 52 segments shows negativereaction in MRI and echocardiography after dobutamine stress respectively. Kappa value of the two techniques is 0.75, concordance in both techniques is 88%. Twenty-four segments showed functional recovery, 14 segments remained dysfunction 3-6 months after revascularization, the sensitivity, specificity and accuracy of detecting myocardial viability in chronic myocardial infarction in MRI and echocardiography is 95.8% vs 79.2% (P>0.05), 85.7% vs 85.7% (P>0.05), 92.1% vs 81.6% (P>0.05) respectively. The sensitivity and accuracy of MRI is a little higher. Conclusion: The ability of detecting myocardial viability by both low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI is similer, the sensitivity and accuracy of MRI is a little higher. (authors)

Impact of functional MRI data preprocessing pipeline on default-mode network detectability in patients with disorders of consciousness

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Adrian eAndronache

2013-08-01

Full Text Available An emerging application of resting-state functional MRI is the study of patients with disorders of consciousness (DoC, where integrity of default-mode network (DMN activity is associated to the clinical level of preservation of consciousness. Due to the inherent inability to follow verbal instructions, arousal induced by scanning noise and postural pain, these patients tend to exhibit substantial levels of movement. This results in spurious, non-neural fluctuations of the blood-oxygen level-dependent (BOLD signal, which impair the evaluation of residual functional connectivity. Here, the effect of data preprocessing choices on the detectability of the DMN was systematically evaluated in a representative cohort of 30 clinically and etiologically heterogeneous DoC patients and 33 healthy controls. Starting from a standard preprocessing pipeline, additional steps were gradually inserted, namely band-pass filtering, removal of co-variance with the movement vectors, removal of co-variance with the global brain parenchyma signal, rejection of realignment outlier volumes and ventricle masking. Both independent-component analysis (ICA and seed-based analysis (SBA were performed, and DMN detectability was assessed quantitatively as well as visually. The results of the present study strongly show that the detection of DMN activity in the sub-optimal fMRI series acquired on DoC patients is contingent on the use of adequate filtering steps. ICA and SBA are differently affected but give convergent findings for high-grade preprocessing. We propose that future studies in this area should adopt the described preprocessing procedures as a minimum standard to reduce the probability of wrongly inferring that DMN activity is absent.

Clinical functional MRI. Persurgical functional neuroimaging. 2. ed.

International Nuclear Information System (INIS)

Stippich, Christoph

2015-01-01

The second, revised edition of this successful textbook provides an up-to-date description of the use of preoperative fMRI in patients with brain tumors and epilepsies. State of the art fMRI procedures are presented, with detailed consideration of practical aspects, imaging and data processing, normal and pathological findings, and diagnostic possibilities and limitations. Relevant information on brain physiology, functional neuroanatomy, imaging technique, and methodology is provided by recognized experts in these fields. Compared with the first edition, chapters have been updated to reflect the latest developments and in particular the current use of diffusion tensor imaging (DTI) and resting-state fMRI. Entirely new chapters are included on resting-state presurgical fMRI and the role of DTI and tractography in brain tumor surgery. Further chapters address multimodality functional neuroimaging, brain plasticity, and pitfalls, tips, and tricks.

Clinical functional MRI. Persurgical functional neuroimaging. 2. ed.

Energy Technology Data Exchange (ETDEWEB)

Stippich, Christoph (ed.) [Univ. Hospitals Basel (Switzerland). Division of Diagnostic and Inventional Neuroradiology

2015-06-01

The second, revised edition of this successful textbook provides an up-to-date description of the use of preoperative fMRI in patients with brain tumors and epilepsies. State of the art fMRI procedures are presented, with detailed consideration of practical aspects, imaging and data processing, normal and pathological findings, and diagnostic possibilities and limitations. Relevant information on brain physiology, functional neuroanatomy, imaging technique, and methodology is provided by recognized experts in these fields. Compared with the first edition, chapters have been updated to reflect the latest developments and in particular the current use of diffusion tensor imaging (DTI) and resting-state fMRI. Entirely new chapters are included on resting-state presurgical fMRI and the role of DTI and tractography in brain tumor surgery. Further chapters address multimodality functional neuroimaging, brain plasticity, and pitfalls, tips, and tricks.

Diffusion, confusion and functional MRI

International Nuclear Information System (INIS)

Le Bihan, Denis

2012-01-01

Diffusion MRI has been introduced in 1985 and has had a very successful life on its own. While it has become a standard for imaging stroke and white matter disorders, the borders between diffusion MRI and the general field of fMRI have always remained fuzzy. First, diffusion MRI has been used to obtain images of brain function, based on the idea that diffusion MRI could also be made sensitive to blood flow, through the intra-voxel incoherent motion (IVIM) concept. Second, the IVIM concept helped better understand the contribution from different vasculature components to the BOLD fMRI signal. Third, it has been shown recently that a genuine fMRI signal can be obtained with diffusion MRI. This 'DfMRI' signal is notably different from the BOLD fMRI signal, especially for its much faster response to brain activation both at onset and offset, which points out to structural changes in the neural tissues, perhaps such as cell swelling, occurring in activated neural tissue. This short article reviews the major steps which have paved the way for this exciting development, underlying how technical progress with MRI equipment has each time been instrumental to expand the horizon of diffusion MRI toward the field of fMRI. (authors)

[Role of MRI for detection and characterization of pulmonary nodules].

Science.gov (United States)

Sommer, G; Koenigkam-Santos, M; Biederer, J; Puderbach, M

2014-05-01

Due to physical and technical limitations, magnetic resonance imaging (MRI) has hitherto played only a minor role in image-based diagnostics of the lungs. However, as a consequence of important methodological developments during recent years, MRI has developed into a technically mature and clinically well-proven method for specific pulmonary questions. The purpose of this article is to provide an overview on the currently available sequences and techniques for assessment of pulmonary nodules and analyzes the clinical significance according to the current literature. The main focus is on the detection of lung metastases, the detection of primary pulmonary malignancies in high-risk individuals and the differentiation between pulmonary nodules of benign and malignant character. The MRI technique has a sensitivity of approximately 80 % for detection of malignant pulmonary nodules compared to the reference standard low-dose computed tomography (CT) and is thus somewhat inferior to CT. Advantages of MRI on the other hand are a higher specificity in differentiating malignant and benign pulmonary nodules and the absence of ionizing radiation exposure. A systematic use of MRI as a primary tool for detection and characterization of pulmonary nodules is currently not recommended due to insufficient data. The diagnostic potential of MRI for early detection and staging of malignant pulmonary diseases, however, seems promising. Therefore, further evaluation of MRI as a secondary imaging modality in clinical trials is highly warranted.

IClinfMRI Software for Integrating Functional MRI Techniques in Presurgical Mapping and Clinical Studies.

Science.gov (United States)

Hsu, Ai-Ling; Hou, Ping; Johnson, Jason M; Wu, Changwei W; Noll, Kyle R; Prabhu, Sujit S; Ferguson, Sherise D; Kumar, Vinodh A; Schomer, Donald F; Hazle, John D; Chen, Jyh-Horng; Liu, Ho-Ling

2018-01-01

Task-evoked and resting-state (rs) functional magnetic resonance imaging (fMRI) techniques have been applied to the clinical management of neurological diseases, exemplified by presurgical localization of eloquent cortex, to assist neurosurgeons in maximizing resection while preserving brain functions. In addition, recent studies have recommended incorporating cerebrovascular reactivity (CVR) imaging into clinical fMRI to evaluate the risk of lesion-induced neurovascular uncoupling (NVU). Although each of these imaging techniques possesses its own advantage for presurgical mapping, a specialized clinical software that integrates the three complementary techniques and promptly outputs the analyzed results to radiology and surgical navigation systems in a clinical format is still lacking. We developed the Integrated fMRI for Clinical Research (IClinfMRI) software to facilitate these needs. Beyond the independent processing of task-fMRI, rs-fMRI, and CVR mapping, IClinfMRI encompasses three unique functions: (1) supporting the interactive rs-fMRI mapping while visualizing task-fMRI results (or results from published meta-analysis) as a guidance map, (2) indicating/visualizing the NVU potential on analyzed fMRI maps, and (3) exporting these advanced mapping results in a Digital Imaging and Communications in Medicine (DICOM) format that are ready to export to a picture archiving and communication system (PACS) and a surgical navigation system. In summary, IClinfMRI has the merits of efficiently translating and integrating state-of-the-art imaging techniques for presurgical functional mapping and clinical fMRI studies.

Altered resting-state functional connectivity in post-traumatic stress disorder: a perfusion MRI study

Science.gov (United States)

Li, Baojuan; Liu, Jian; Liu, Yang; Lu, Hong-Bing; Yin, Hong

2013-03-01

The majority of studies on posttraumatic stress disorder (PTSD) so far have focused on delineating patterns of activations during cognitive processes. Recently, more and more researches have started to investigate functional connectivity in PTSD subjects using BOLD-fMRI. Functional connectivity analysis has been demonstrated as a powerful approach to identify biomarkers of different brain diseases. This study aimed to detect resting-state functional connectivity abnormities in patients with PTSD using arterial spin labeling (ASL) fMRI. As a completely non-invasive technique, ASL allows quantitative estimates of cerebral blood flow (CBF). Compared with BOLD-fMRI, ASL fMRI has many advantages, including less low-frequency signal drifts, superior functional localization, etc. In the current study, ASL images were collected from 10 survivors in mining disaster with recent onset PTSD and 10 survivors without PTSD. Decreased regional CBF in the right middle temporal gyrus, lingual gyrus, and postcentral gyrus was detected in the PTSD patients. Seed-based resting-state functional connectivity analysis was performed using an area in the right middle temporal gyrus as region of interest. Compared with the non-PTSD group, the PTSD subjects demonstrated increased functional connectivity between the right middle temporal gyrus and the right superior temporal gyrus, the left middle temporal gyrus. Meanwhile, decreased functional connectivity between the right middle temporal gyrus and the right postcentral gyrus, the right superior parietal lobule was also found in the PTSD patients. This is the first study which investigated resting-state functional connectivity in PTSD using ASL images. The results may provide new insight into the neural substrates of PTSD.

Detection of rotator cuff tears: the value of MRI following ultrasound

International Nuclear Information System (INIS)

Rutten, Matthieu J.C.M.; Spaargaren, Gert-Jan; Jager, Gerrit J.; Loon, Ton van; Waal Malefijt, Maarten C. de; Kiemeney, Lambertus A.L.M.

2010-01-01

To evaluate the need for additional magnetic resonance imaging (MRI) following ultrasound (US) in patients with shoulder pain and/or disability and to compare the accuracy of both techniques for the detection of partial-thickness and full-thickness rotator cuff tears (RCT). In 4 years, 5,216 patients underwent US by experienced musculoskeletal radiologists. Retrospectively, patient records were evaluated if MRI and surgery were performed within 5 months of US. US and MRI findings were classified into intact cuff, partial-thickness and full-thickness RCT, and were correlated with surgical findings. Additional MR imaging was performed in 275 (5.2%) patients. Sixty-eight patients underwent surgery within 5 months. US and MRI correctly depicted 21 (95%) and 22 (100%) of the 22 full-thickness tears, and 8 (89%) and 6 (67%) of the 9 partial-thickness tears, respectively. The differences in performance of US and MRI were not statistically significant (p = 0.15). MRI following routine shoulder US was requested in only 5.2% of the patients. The additional value of MRI was in detecting intra-articular lesions. In patients who underwent surgery, US and MRI yielded comparably high sensitivity for detecting full-thickness RCT. US performed better in detecting partial-thickness tears, although the difference was not significant. (orig.)

Detection of rotator cuff tears: the value of MRI following ultrasound

Energy Technology Data Exchange (ETDEWEB)

Rutten, Matthieu J.C.M.; Spaargaren, Gert-Jan; Jager, Gerrit J. [Jeroen Bosch Ziekenhuis, Department of Radiology, NL' s-Hertogenbosch (Netherlands); Loon, Ton van [Jeroen Bosch Ziekenhuis, Department of Orthopedic Surgery, NL' s-Hertogenbosch (Netherlands); Waal Malefijt, Maarten C. de [Radboud University Nijmegen Medical Centre, Department of Orthopedic Surgery, Nijmegen (Netherlands); Kiemeney, Lambertus A.L.M. [Radboud University Nijmegen Medical Centre, Department of Epidemiology and Biostatistics and HTA, Geert Grooteplein Noord 21, P.O. Box 9101, Nijmegen (Netherlands)

2010-02-15

To evaluate the need for additional magnetic resonance imaging (MRI) following ultrasound (US) in patients with shoulder pain and/or disability and to compare the accuracy of both techniques for the detection of partial-thickness and full-thickness rotator cuff tears (RCT). In 4 years, 5,216 patients underwent US by experienced musculoskeletal radiologists. Retrospectively, patient records were evaluated if MRI and surgery were performed within 5 months of US. US and MRI findings were classified into intact cuff, partial-thickness and full-thickness RCT, and were correlated with surgical findings. Additional MR imaging was performed in 275 (5.2%) patients. Sixty-eight patients underwent surgery within 5 months. US and MRI correctly depicted 21 (95%) and 22 (100%) of the 22 full-thickness tears, and 8 (89%) and 6 (67%) of the 9 partial-thickness tears, respectively. The differences in performance of US and MRI were not statistically significant (p = 0.15). MRI following routine shoulder US was requested in only 5.2% of the patients. The additional value of MRI was in detecting intra-articular lesions. In patients who underwent surgery, US and MRI yielded comparably high sensitivity for detecting full-thickness RCT. US performed better in detecting partial-thickness tears, although the difference was not significant. (orig.)

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...... will have very few or no clinical symptoms, or it could be due to compensatory mechanisms in the visual pathway or the visual cortex. In order to understand the pathophysiology and recovery processes in ON it is essential to have sensitive methods to asses both structure and function. These methods...... 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...

Physiological and technical limitations of functional magnetic resonance imaging (fMRI) - consequences for clinical use

International Nuclear Information System (INIS)

Wuestenberg, T.; Jordan, K.; Giesel, F.L.; Villringer, A.

2003-01-01

Functional magnetic resonance imaging (fMRI) is the most common noninvasive technique in functional neuroanatomy. The capabilities and limitations of the method will be discussed based on a short review of the current knowledge about the neurovascular relationship. The focus of this article is on current methodical and technical problems regarding fMRI-based detection and localization of neuronal activity. Main error sources and their influence on the reliability and validity of fMRI-methods are presented. Appropriate solution strategies will be proposed and evaluated. Finally, the clinical relevance of MR-based diagnostic methods are discussed. (orig.) [de

Novel fMRI working memory paradigm accurately detects cognitive impairment in Multiple Sclerosis

Science.gov (United States)

Nelson, Flavia; Akhtar, Mohammad A.; Zúñiga, Edward; Perez, Carlos A.; Hasan, Khader M.; Wilken, Jeffrey; Wolinsky, Jerry S.; Narayana, Ponnada A.; Steinberg, Joel L.

2016-01-01

Background Cognitive impairment (CI) cannot be diagnosed by MRI. Functional MRI (fMRI) paradigms such as the immediate/delayed memory task (I/DMT), detect varying degrees of working memory. Preliminary findings using I/DMT, showed differences in Blood Oxygenation Level Dependent (BOLD) activation between impaired (MSCI, n=12) and non-impaired (MSNI, n=9) MS patients. Objectives To confirm CI detection based on I/DMT’ BOLD activation in a larger cohort of MS patients. The role of T2 lesion volume (LV) and EDSS in magnitude of BOLD signal were also sought. Methods Fifty patients [EDSS mean (m) = 3.2, DD m =12 yr., age m =40yr.] underwent the Minimal Assessment of Cognitive Function in MS (MACFIMS) and the I/DMT. Working-memory activation (WMa) represents BOLD signal during DMT minus signal during IMT. CI was based on MACFIMS. Results 10 MSNI, 30 MSCI and 4 borderline patients were included in analyses. ANOVA showed MSNI had significantly greater WMa than MSCI, in the left (L) prefrontal cortex and L supplementary motor area (p = 0.032). Regression analysis showed significant inverse correlations between WMa and T2 LV/EDSS in similar areas (p = 0.005, 0.004 respectively). Conclusion I/DMT-based BOLD activation detects CI in MS, larger studies are needed to confirm these findings. PMID:27613119

Exploring structure and function of sensory cortex with 7T MRI.

Science.gov (United States)

Schluppeck, Denis; Sanchez-Panchuelo, Rosa-Maria; Francis, Susan T

2018-01-01

In this paper, we present an overview of 7T magnetic resonance imaging (MRI) studies of the detailed function and anatomy of sensory areas of the human brain. We discuss the motivation for the studies, with particular emphasis on increasing the spatial resolution of functional MRI (fMRI) using reduced field-of-view (FOV) data acquisitions. MRI at ultra-high-field (UHF) - defined here as 7T and above - has several advantages over lower field strengths. The intrinsic signal-to-noise ratio (SNR) of images is higher at UHF, and coupled with the increased blood-oxygen-level-dependent (BOLD) signal change, this results in increased BOLD contrast-to-noise ratio (CNR), which can be exploited to improve spatial resolution or detect weaker signals. Additionally, the BOLD signal from the intra-vascular (IV) compartment is relatively diminished compared to lower field strengths. Together, these properties make 7T functional MRI an attractive proposition for high spatial specificity measures. But with the advantages come some challenges. For example, increased vulnerability to susceptibility-induced geometric distortions and signal loss in EPI acquisitions tend to be much larger. Some of these technical issues can be addressed with currently available tools and will be discussed. We highlight the key methodological considerations for high resolution functional and structural imaging at 7 T. We then present recent data using the high spatial resolution available at UHF in studies of the visual and somatosensory cortex to highlight promising developments in this area. Copyright © 2017 Elsevier Inc. All rights reserved.

Asymptomatic cerebral hemorrhage detected by MRI

International Nuclear Information System (INIS)

Nakajima, Yumi; Ohsuga, Hitoshi; Yamamoto, Masahiro; Shinohara, Yukito

1991-01-01

Detection of previous cerebral infarction on CT films of patients with no history of stroke is a common occurrence. The incidence of silent cerebral infarction was reported to be about 10 to 11 percent, but very few reports concerning asymptomatic cerebral hemorrhage available. However, recent clinical application of MRI has resulted in the detection of old asymptomatic hemorrhage in patients with no history known stroke-like episodes. The purpose of this study was to elucidate the incidence, the cause and the character of the asymptomatic cerebral hemorrhage among patients who had undergone MRI examinations. From September 1987 through June 1990, 2757 patients have undergone 3474 MR scans of the brain with 1.0 Tesla Siemens Magneton unit in our hospital. Seventeen patients showed no clinical signs or symptoms suggesting a stroke episode corresponding to the detected hemorrhagic lesion. The 17 patients corresponded to 0.6% of the patients who underwent MRI, 1.5% of the patients with cerebrovascular disease and 9.5% of the patients with intracerebral hemorrhage(ICH), which was rather higher than expected. Among the 17 patients, 12 were diagnosed as primary ICH and 5 as secondary ICH. Most of the primary asymptomatic hemorrhage were hypertensive ones and slit-like curvilinear lesions between the putamen and claustrum or external capsule. The secondary asymptomatic hemorrhage were due to AVM and angiomas in the frontal cortex, thalamus and pons. (author)

Asymptomatic cerebral hemorrhage detected by MRI

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Nakajima, Yumi; Ohsuga, Hitoshi; Yamamoto, Masahiro; Shinohara, Yukito [Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine

1991-03-01

Detection of previous cerebral infarction on CT films of patients with no history of stroke is a common occurrence. The incidence of silent cerebral infarction was reported to be about 10 to 11 percent, but very few reports concerning asymptomatic cerebral hemorrhage available. However, recent clinical application of MRI has resulted in the detection of old asymptomatic hemorrhage in patients with no history known stroke-like episodes. The purpose of this study was to elucidate the incidence, the cause and the character of the asymptomatic cerebral hemorrhage among patients who had undergone MRI examinations. From September 1987 through June 1990, 2757 patients have undergone 3474 MR scans of the brain with 1.0 Tesla Siemens Magneton unit in our hospital. Seventeen patients showed no clinical signs or symptoms suggesting a stroke episode corresponding to the detected hemorrhagic lesion. The 17 patients corresponded to 0.6% of the patients who underwent MRI, 1.5% of the patients with cerebrovascular disease and 9.5% of the patients with intracerebral hemorrhage(ICH), which was rather higher than expected. Among the 17 patients, 12 were diagnosed as primary ICH and 5 as secondary ICH. Most of the primary asymptomatic hemorrhage were hypertensive ones and slit-like curvilinear lesions between the putamen and claustrum or external capsule. The secondary asymptomatic hemorrhage were due to AVM and angiomas in the frontal cortex, thalamus and pons. (author).

Imaging tools to study pharmacology: functional MRI on small rodents

OpenAIRE

Elisabeth eJonckers; Disha eShah; Julie eHamaide; Marleen eVerhoye; Annemie eVan Der Linden

2015-01-01

Functional Magnetic Resonance Imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimu...

Management of breast lesions detectable only on MRI

International Nuclear Information System (INIS)

Siegmann-Luz, K.C.; Bahrs, S.D.; Preibsch, H.; Hattermann, V.; Claussen, C.D.

2014-01-01

Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline 'Diagnosis, Therapy, and Follow-Up of Breast Cancer' as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. (orig.)

Does functional MRI detect activation in white matter? A review of emerging evidence, issues, and future directions

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Gawryluk, Jodie R.; Mazerolle, Erin L.; D'Arcy, Ryan C. N.

2014-01-01

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: (1) the blood oxygen level dependent (BOLD) fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and (2) fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter) as opposed to action potentials (the primary type of neural activity in white matter). Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI. PMID:25152709

Imaging tools to study pharmacology: functional MRI on small rodents

Directory of Open Access Journals (Sweden)

Elisabeth eJonckers

2015-10-01

Full Text Available Functional Magnetic Resonance Imaging (fMRI is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD fMRI techniques, including resting state (rsfMRI, stimulus-evoked (st-fMRI, and pharmacological MRI (phMRI. Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimulation and/or a pharmacological challenge. The first part of this review describes the physiological basis of BOLD fMRI and the hemodynamic response on which the MRI contrast is based. Specific emphasis goes to possible effects of anaesthesia and the animal’s physiological conditions on neural activity and the hemodynamic response. The second part of this review describes applications of the aforementioned techniques in pharmacologically-induced, as well as in traumatic and transgenic disease models and illustrates how multiple fMRI methods can be applied successfully to evaluate different aspects of a specific disorder. For example, fMRI techniques can be used to pinpoint the neural substrate of a disease beyond previously defined hypothesis-driven regions-of-interest (ROIs. In addition, fMRI techniques allow one to dissect how specific modifications (e.g. treatment, lesion etc. modulate the functioning of specific brain areas (st-fMRI, phMRI and how functional connectivity (rsfMRI between several brain regions is affected, both in acute and extended time frames. Furthermore, fMRI techniques can be used to assess/explore the efficacy of novel treatments in depth, both in fundamental research as well as in preclinical settings. In conclusion, by describing several exemplary studies, we aim to highlight the advantages of functional MRI in exploring the acute and long-term effects of pharmacological substances and/or pathology on brain functioning along with

Large-scale Granger causality analysis on resting-state functional MRI

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D'Souza, Adora M.; Abidin, Anas Zainul; Leistritz, Lutz; Wismüller, Axel

2016-03-01

We demonstrate an approach to measure the information flow between each pair of time series in resting-state functional MRI (fMRI) data of the human brain and subsequently recover its underlying network structure. By integrating dimensionality reduction into predictive time series modeling, large-scale Granger Causality (lsGC) analysis method can reveal directed information flow suggestive of causal influence at an individual voxel level, unlike other multivariate approaches. This method quantifies the influence each voxel time series has on every other voxel time series in a multivariate sense and hence contains information about the underlying dynamics of the whole system, which can be used to reveal functionally connected networks within the brain. To identify such networks, we perform non-metric network clustering, such as accomplished by the Louvain method. We demonstrate the effectiveness of our approach to recover the motor and visual cortex from resting state human brain fMRI data and compare it with the network recovered from a visuomotor stimulation experiment, where the similarity is measured by the Dice Coefficient (DC). The best DC obtained was 0.59 implying a strong agreement between the two networks. In addition, we thoroughly study the effect of dimensionality reduction in lsGC analysis on network recovery. We conclude that our approach is capable of detecting causal influence between time series in a multivariate sense, which can be used to segment functionally connected networks in the resting-state fMRI.

Diagnostic imaging strategy for MDCT- or MRI-detected breast lesions: use of targeted sonography

International Nuclear Information System (INIS)

Nakano, Satoko; Ohtsuka, Masahiko; Mibu, Akemi; Karikomi, Masato; Sakata, Hitomi; Yamamoto, Masahiro

2012-01-01

Leading-edge technology such as magnetic resonance imaging (MRI) or computed tomography (CT) often reveals mammographically and ultrasonographically occult lesions. MRI is a well-documented, effective tool to evaluate these lesions; however, the detection rate of targeted sonography varies for MRI detected lesions, and its significance is not well established in diagnostic strategy of MRI detected lesions. We assessed the utility of targeted sonography for multidetector-row CT (MDCT)- or MRI-detected lesions in practice. We retrospectively reviewed 695 patients with newly diagnosed breast cancer who were candidates for breast conserving surgery and underwent MDCT or MRI in our hospital between January 2004 and March 2011. Targeted sonography was performed in all MDCT- or MRI-detected lesions followed by imaging-guided biopsy. Patient background, histopathology features and the sizes of the lesions were compared among benign, malignant and follow-up groups. Of the 695 patients, 61 lesions in 56 patients were detected by MDCT or MRI. The MDCT- or MRI-detected lesions were identified by targeted sonography in 58 out of 61 lesions (95.1%). Patients with pathological diagnoses were significantly older and more likely to be postmenopausal than the follow-up patients. Pathological diagnosis proved to be benign in 20 cases and malignant in 25. The remaining 16 lesions have been followed up. Lesion size and shape were not significantly different among the benign, malignant and follow-up groups. Approximately 95% of MDCT- or MRI-detected lesions were identified by targeted sonography, and nearly half of these lesions were pathologically proven malignancies in this study. Targeted sonography is a useful modality for MDCT- or MRI-detected breast lesions

High temporal resolution functional MRI using parallel echo volumar imaging

International Nuclear Information System (INIS)

Rabrait, C.; Ciuciu, P.; Ribes, A.; Poupon, C.; Dehaine-Lambertz, G.; LeBihan, D.; Lethimonnier, F.; Le Roux, P.; Dehaine-Lambertz, G.

2008-01-01

Purpose: To combine parallel imaging with 3D single-shot acquisition (echo volumar imaging, EVI) in order to acquire high temporal resolution volumar functional MRI (fMRI) data. Materials and Methods: An improved EVI sequence was associated with parallel acquisition and field of view reduction in order to acquire a large brain volume in 200 msec. Temporal stability and functional sensitivity were increased through optimization of all imaging parameters and Tikhonov regularization of parallel reconstruction. Two human volunteers were scanned with parallel EVI in a 1.5 T whole-body MR system, while submitted to a slow event-related auditory paradigm. Results: Thanks to parallel acquisition, the EVI volumes display a low level of geometric distortions and signal losses. After removal of low-frequency drifts and physiological artifacts,activations were detected in the temporal lobes of both volunteers and voxel-wise hemodynamic response functions (HRF) could be computed. On these HRF different habituation behaviors in response to sentence repetition could be identified. Conclusion: This work demonstrates the feasibility of high temporal resolution 3D fMRI with parallel EVI. Combined with advanced estimation tools,this acquisition method should prove useful to measure neural activity timing differences or study the nonlinearities and non-stationarities of the BOLD response. (authors)

MRI evaluation and functional assessment of brain injury after hypoxic ischemia in neonatal mice.

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Adén, Ulrika; Dahlberg, Viktoria; Fredholm, Bertil B; Lai, Li-Ju; Chen, Zhengguan; Bjelke, Börje

2002-05-01

Severe perinatal asphyxia is an important cause of brain injury in the newborn infant. We examined early events after hypoxic ischemia (HI) in the 7-day-old mouse brain by MRI and related them to long-term functional effects and histopathology in the same animals at 4 to 5 weeks of age. HI was induced in 7-day-old CD1 mice by exposure to 8% oxygen for 30 minutes after occlusion of the left common carotid artery. The resulting unilateral focal lesion was evaluated in vivo by MRI (T2 maps and apparent diffusion coefficient maps) at 3, 6, and 24 hours and 5 days after hypoxia. Locomotion and sensorimotor function were analyzed after 3 weeks. Four weeks after HI, the mice were killed, and cresyl violet-stained brain sections were examined morphologically. A decrease in apparent diffusion coefficient values in cortex on the affected side was found at 3 hours after HI. T2 values were significantly increased after 6 hours and remained so for 5 days. Maximal size of the lesion was attained at 3 to 6 hours after HI and declined thereafter. Animals with MRI-detected lesions had decreased forward locomotion, performed worse than controls in the beam-walking test, and showed a unilateral hypotrophy in the cresyl violet-stained brain sections 4 weeks later. The temporal progression of the damage after HI in 7-day-old mice differs from that of the adult brain as judged by MRI. The early lesions detected by MRI were related to functional impairments for these mice in near-adult life.

Detection of Brain Reorganization in Pediatric Multiple Sclerosis Using Functional MRI

Science.gov (United States)

2014-10-01

7.5 years). Pediatric temporal lobe epilepsy patients who undergo clinically-indicated Wada test and/or implantation of subdural electrodes with...cohort. 2.6. Validation of fMRI in temporal lobe epilepsy patients: The validation of passive language fMRI was carried out on patient cohort 1...made up of 15 pediatric-onset temporal lobe epilepsy surgical patients all of whom had some form of invasive mapping for comparisons against fMRI

Annexin V–CLIO: A Nanoparticle for Detecting Apoptosis by MRI

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Eyk A. Schellenberger

2002-04-01

Full Text Available Annexin V, which recognizes the phosphatidylserine of apoptotic cells, was conjugated to crosslinked iron oxide (CLIO nanoparticles, a functionalized superparamagnetic preparation developed for target-specific magnetic resonance imaging (MRI. The resulting nanoparticle had an average of 2.7 annexin V proteins linked per CLIO nanoparticle through disulfide bonds. Using camptothecin to induce apoptosis, a mixture of Jurkat T cells (69% healthy and 31% apoptotic was incubated with annexin V–CLIO and was applied to magnetic columns. The result was an almost complete removal of the apoptotic cells (>99%. In a phantom MRI experiment, untreated control cells (12% apoptotic cells, 88% healthy cells and camptothecin-treated cells (65% apoptotic cells, 35% healthy cells were incubated with either annexin V–CLIO (1.0, 0.5, and 0.1 μg Fe/mL or with unlabeled CLIO. A significant signal decrease of camptothecin-treated cells relative to untreated cells was observed even at the lowest concentration tested. Unmodified CLIO failed to cause a significant signal change of apoptotic cells. Hence, annexin V–CLIO allowed the identification of cell suspensions containing apoptotic cells by MRI even at very low concentrations of magnetic substrate. Conjugation of annexin V to CLIO affords a strategy for the development of a MRI imaging probe for detecting apoptosis.

Incremental Activation Detection for Real-Time fMRI Series Using Robust Kalman Filter

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Liang Li

2014-01-01

Full Text Available Real-time functional magnetic resonance imaging (rt-fMRI is a technique that enables us to observe human brain activations in real time. However, some unexpected noises that emerged in fMRI data collecting, such as acute swallowing, head moving and human manipulations, will cause much confusion and unrobustness for the activation analysis. In this paper, a new activation detection method for rt-fMRI data is proposed based on robust Kalman filter. The idea is to add a variation to the extended kalman filter to handle the additional sparse measurement noise and a sparse noise term to the measurement update step. Hence, the robust Kalman filter is designed to improve the robustness for the outliers and can be computed separately for each voxel. The algorithm can compute activation maps on each scan within a repetition time, which meets the requirement for real-time analysis. Experimental results show that this new algorithm can bring out high performance in robustness and in real-time activation detection.

MRI to assess renal structure and function.

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Artunc, Ferruh; Rossi, Cristina; Boss, Andreas

2011-11-01

In addition to excellent anatomical depiction, MRI techniques have expanded to study functional aspects of renal physiology, such as renal perfusion, glomerular filtration rate (GFR) or tissue oxygenation. This review will focus on current developments with an emphasis on clinical applicability. The method of GFR determination is largely heterogeneous and still has weaknesses. However, the technique of employing liver disappearance curves has been shown to be accurate in healthy persons and patients with chronic kidney disease. In potential kidney donors, complete evaluation of kidney anatomy and function can be accomplished in a single-stop investigation. Techniques without contrast media can be utilized to measure renal tissue oxygenation (blood oxygen level-dependent MRI) or perfusion (arterial spin labeling) and could aid in the diagnosis and treatment of ischemic renal diseases, such as renal artery stenosis. Diffusion imaging techniques may provide information on spatially restricted water diffusion and tumor cellularity. Functional MRI opens new horizons in studying renal physiology and pathophysiology in vivo. Although extensively utilized in research, labor-intensive postprocessing and lack of standardization currently limit the clinical applicability of functional MRI. Further studies are necessary to evaluate the clinical value of functional magnetic resonance techniques for early discovery and characterization of kidney disease.

Function-specific and Enhanced Brain Structural Connectivity Mapping via Joint Modeling of Diffusion and Functional MRI.

Science.gov (United States)

Chu, Shu-Hsien; Parhi, Keshab K; Lenglet, Christophe

2018-03-16

A joint structural-functional brain network model is presented, which enables the discovery of function-specific brain circuits, and recovers structural connections that are under-estimated by diffusion MRI (dMRI). Incorporating information from functional MRI (fMRI) into diffusion MRI to estimate brain circuits is a challenging task. Usually, seed regions for tractography are selected from fMRI activation maps to extract the white matter pathways of interest. The proposed method jointly analyzes whole brain dMRI and fMRI data, allowing the estimation of complete function-specific structural networks instead of interactively investigating the connectivity of individual cortical/sub-cortical areas. Additionally, tractography techniques are prone to limitations, which can result in erroneous pathways. The proposed framework explicitly models the interactions between structural and functional connectivity measures thereby improving anatomical circuit estimation. Results on Human Connectome Project (HCP) data demonstrate the benefits of the approach by successfully identifying function-specific anatomical circuits, such as the language and resting-state networks. In contrast to correlation-based or independent component analysis (ICA) functional connectivity mapping, detailed anatomical connectivity patterns are revealed for each functional module. Results on a phantom (Fibercup) also indicate improvements in structural connectivity mapping by rejecting false-positive connections with insufficient support from fMRI, and enhancing under-estimated connectivity with strong functional correlation.

Extraction of temporal information in functional MRI

Science.gov (United States)

Singh, M.; Sungkarat, W.; Jeong, Jeong-Won; Zhou, Yongxia

2002-10-01

The temporal resolution of functional MRI (fMRI) is limited by the shape of the haemodynamic response function (hrf) and the vascular architecture underlying the activated regions. Typically, the temporal resolution of fMRI is on the order of 1 s. We have developed a new data processing approach to extract temporal information on a pixel-by-pixel basis at the level of 100 ms from fMRI data. Instead of correlating or fitting the time-course of each pixel to a single reference function, which is the common practice in fMRI, we correlate each pixel's time-course to a series of reference functions that are shifted with respect to each other by 100 ms. The reference function yielding the highest correlation coefficient for a pixel is then used as a time marker for that pixel. A Monte Carlo simulation and experimental study of this approach were performed to estimate the temporal resolution as a function of signal-to-noise ratio (SNR) in the time-course of a pixel. Assuming a known and stationary hrf, the simulation and experimental studies suggest a lower limit in the temporal resolution of approximately 100 ms at an SNR of 3. The multireference function approach was also applied to extract timing information from an event-related motor movement study where the subjects flexed a finger on cue. The event was repeated 19 times with the event's presentation staggered to yield an approximately 100-ms temporal sampling of the haemodynamic response over the entire presentation cycle. The timing differences among different regions of the brain activated by the motor task were clearly visualized and quantified by this method. The results suggest that it is possible to achieve a temporal resolution of /spl sim/200 ms in practice with this approach.

Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

International Nuclear Information System (INIS)

Kulemann, Vanessa; Schima, Wolfgang; Tamandl, Dietmar; Kaczirek, Klaus; Gruenberger, Thomas; Wrba, Friedrich; Weber, Michael; Ba-Ssalamah, Ahmed

2011-01-01

Objective: To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy. Materials and methods: Twenty preoperative tri-phasic MDCT (4-64-row, Siemens) and dynamic contrast-enhanced MRI (1.5 T or 3.0 T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1-60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%. Results: Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1 cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1 cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference (p 1 cm. Conclusion: For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.

Can breast MRI computer-aided detection (CAD) improve radiologist accuracy for lesions detected at MRI screening and recommended for biopsy in a high-risk population?

International Nuclear Information System (INIS)

Arazi-Kleinman, T.; Causer, P.A.; Jong, R.A.; Hill, K.; Warner, E.

2009-01-01

Aim: To evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) computer-aided detection (CAD) for breast MRI screen-detected lesions recommended for biopsy in a high-risk population. Material and methods: Fifty-six consecutive Breast Imaging Reporting and Data System (BI-RADS) 3-5 lesions with histopathological correlation [nine invasive cancers, 13 ductal carcinoma in situ (DCIS) and 34 benign] were retrospectively evaluated using a breast MRI CAD prototype (CAD-Gaea). CAD evaluation was performed separately and in consensus by two radiologists specializing in breast imaging, blinded to the histopathology. Thresholds of 50, 80, and 100% and delayed enhancement were independently assessed with CAD. Lesions were rated as malignant or benign according to threshold and delayed enhancement only and in combination. Sensitivities, specificities, and negative predictive values (NPV) were determined for CAD assessments versus pathology. Initial MRI BI-RADS interpretation without CAD versus CAD assessments were compared using paired binary diagnostic tests. Results: Threshold levels for lesion enhancement were: 50% to include all malignant (and all benign) lesions; and 100% for all invasive cancer and high-grade DCIS. Combined use of threshold and enhancement patterns for CAD assessment was best (73% sensitivity, 56% specificity and 76% NPV for all cancer). Sensitivities and NPV were better for invasive cancer (100%/100%) than for all malignancies (54%/76%). Radiologists' MRI interpretation was more sensitive than CAD (p = 0.05), but less specific (p = 0.001) for cancer detection. Conclusion: The breast MRI CAD system used could not improve the radiologists' accuracy for distinguishing all malignant from benign lesions, due to the poor sensitivity for DCIS detection.

Intrinsically radiolabelled [(59)Fe]-SPIONs for dual MRI/radionuclide detection.

Science.gov (United States)

Hoffman, David; Sun, Minghao; Yang, Likun; McDonagh, Philip R; Corwin, Frank; Sundaresan, Gobalakrishnan; Wang, Li; Vijayaragavan, Vimalan; Thadigiri, Celina; Lamichhane, Narottam; Zweit, Jamal

2014-01-01

Towards the development of iron oxide nanoparticles with intrinsically incorporated radionuclides for dual Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) and more recently of Single Photon Emission Computed Tomography/Magnetic Resonance Imaging (SPECT/MRI), we have developed intrinsically radiolabeled [(59)Fe]-superparamagnetic iron oxide nanoparticles ([(59)Fe]-SPIONs) as a proof of concept for an intrinsic dual probe strategy. (59)Fe was incorporated into Fe3O4 nanoparticle crystal lattice with 92±3% efficiency in thermal decomposition synthesis. Multidentate poly(acrylic acid)-dopamine-poly(ethylene-glycol-2000) (PAA-DOP-PEG) ligands were designed and synthesized based on facile EDC chemistry and utilized to functionalize the [(59)Fe]-SPIONs. The transverse relaxivity of [(59)Fe]-SPIONs (97±3 s(-1)mM(-1)) was characterized and found to be similar to non-radioactive SPIONs (72±10 s(-1)mM(-1)), indicating that (59)Fe incorporation does not alter the SPIONs' MRI contrast properties. [(59)Fe]-SPIONs were used to evaluate the nanoparticle biodistribution by ex vivo gamma counting and MRI. Nude mice (n=15) were injected with [(59)Fe]-SPIONs and imaged at various time points with 7T small animal MRI scanner. Ex vivo biodistribution was evaluated by tissue-based gamma counting. MRI signal contrast qualitatively correlates with the %ID/g of [(59)Fe]-SPIONs, with high contrast in liver (45±6%), medium contrast in kidneys (21±5%), and low contrast in brain (4±6%) at 24 hours. This work demonstrates the synthesis and in vivo application of intrinsically radiolabeled [(59)Fe]-SPIONs for bimodal detection and provides a proof of concept for incorporation of both gamma- and positron-emitting inorganic radionuclides into the core of metal based MRI contrast agent nanoparticles.

Multivariate spatial Gaussian mixture modeling for statistical clustering of hemodynamic parameters in functional MRI

International Nuclear Information System (INIS)

Fouque, A.L.; Ciuciu, Ph.; Risser, L.; Fouque, A.L.; Ciuciu, Ph.; Risser, L.

2009-01-01

In this paper, a novel statistical parcellation of intra-subject functional MRI (fMRI) data is proposed. The key idea is to identify functionally homogenous regions of interest from their hemodynamic parameters. To this end, a non-parametric voxel-based estimation of hemodynamic response function is performed as a prerequisite. Then, the extracted hemodynamic features are entered as the input data of a Multivariate Spatial Gaussian Mixture Model (MSGMM) to be fitted. The goal of the spatial aspect is to favor the recovery of connected components in the mixture. Our statistical clustering approach is original in the sense that it extends existing works done on univariate spatially regularized Gaussian mixtures. A specific Gibbs sampler is derived to account for different covariance structures in the feature space. On realistic artificial fMRI datasets, it is shown that our algorithm is helpful for identifying a parsimonious functional parcellation required in the context of joint detection estimation of brain activity. This allows us to overcome the classical assumption of spatial stationarity of the BOLD signal model. (authors)

Role of New Functional MRI Techniques in the Diagnosis, Staging, and Followup of Gynecological Cancer: Comparison with PET-CT

Directory of Open Access Journals (Sweden)

Elena Alvarez Moreno

2012-01-01

Full Text Available Recent developments in diagnostic imaging techniques have magnified the role and potential of both MRI and PET-CT in female pelvic imaging. This article reviews the techniques and clinical applications of new functional MRI (fMRI including diffusion-weighted MRI (DWI, dynamic contrast-enhanced (DCE-MRI, comparing with PET-CT. These new emerging provide not only anatomic but also functional imaging, allowing detection of small volumes of active tumor at diagnosis and early disease relapse, which may not result in detectable morphological changes at conventional imaging. This information is useful in distinguishing between recurrent/residual tumor and post-treatment changes and assessing treatment response, with a clear impact on patient management. Both PET-CT and now fMRI have proved to be very valuable tools for evaluation of gynecologic tumors. Most papers try to compare these techniques, but in our experience both are complementary in management of these patients. Meanwhile PET-CT is superior in diagnosis of ganglionar disease; fMRI presents higher accuracy in local preoperative staging. Both techniques can be used as biomarkers of tumor response and present high accuracy in diagnosis of local recurrence and peritoneal dissemination, with complementary roles depending on histological type, anatomic location and tumoral volume.

Added value of diffusion-weighted MRI in detection of cervical cancer recurrence: comparison with morphologic and dynamic contrast-enhanced MRI sequences.

Science.gov (United States)

Lucas, Rita; Lopes Dias, João; Cunha, Teresa Margarida

2015-01-01

We aimed to evaluate the added value of diffusion-weighted imaging (DWI) to standard magnetic resonance imaging (MRI) for detecting post-treatment cervical cancer recurrence. The detection accuracy of T2-weighted (T2W) images was compared with that of T2W MRI combined with either dynamic contrast-enhanced (DCE) MRI or DWI. Thirty-eight women with clinically suspected uterine cervical cancer recurrence more than six months after treatment completion were examined with 1.5 Tesla MRI including T2W, DCE, and DWI sequences. Disease was confirmed histologically and correlated with MRI findings. The diagnostic performance of T2W imaging and its combination with either DCE or DWI were analyzed. Sensitivity, positive predictive value, and accuracy were calculated. Thirty-six women had histologically proven recurrence. The accuracy for recurrence detection was 80% with T2W/DCE MRI and 92.1% with T2W/DWI. The addition of DCE sequences did not significantly improve the diagnostic ability of T2W imaging, and this sequence combination misclassified two patients as falsely positive and seven as falsely negative. The T2W/DWI combination revealed a positive predictive value of 100% and only three false negatives. The addition of DWI to T2W sequences considerably improved the diagnostic ability of MRI. Our results support the inclusion of DWI in the initial MRI protocol for the detection of cervical cancer recurrence, leaving DCE sequences as an option for uncertain cases.

Study of human brain functions by functional magnetic resonance imaging (fMRI) and spectroscopy (fMRS)

International Nuclear Information System (INIS)

Jagannathan, N.R.

1998-01-01

Functional magnetic resonance imaging (fMRI) has become a powerful tool in the detection and assessment of cerebral pathophysiology and the regional mapping and characterization of cognitive processes such as motor skills, vision, language and memory. The results of the effect of motor cortex stimulation during repetitive hand squeezing task activation using in-vivo single voxel NMR spectroscopy carried out on normal volunteer subjects are presented

Neuro-pharmacological functional MRI of epilepsy

Energy Technology Data Exchange (ETDEWEB)

Kiriyama, Hideki; Makabe, Tetsuo; Tomita, Susumu; Omoto, Takashi; Asari, Shoji [Okayama Univ. (Japan). School of Medicine; Aihara, Hiroshi; Kinugasa, Kazushi; Nishimoto, Akira; Ito, Takahiko

2000-03-01

We studied patients with epilepsy by neuro-pharmacological functional MRI technique using diazepam. Five normal volunteers and 7 patients with epilepsy were investigated. MRI was performed by a 1.5 T unit (SIGNA Horizon, GE) using the following parameters: TR/TE 5000 msec/80 msec, FA 90 deg, FOV 200 mm, matrix 128 x 128, slice thickness 7 mm. We performed MRI scanning over 5 minutes (2 minutes before and 3 minutes after injection of diazepam) for each 1 session; we scanned 3 sessions for each patient at intervals of 5 minutes. The diazepam was injected rapidly from the antecubital vein. The dose of diazepam was 0.05 mg/kg/injection (total dose was 0.15 mg/kg). The data were analyzed statistically using t-test. Signal change after administration of diazepam was less than 1 to 2% in healthy volunteers. By contrast, in patient with epilepsy, the signal change was almost 3%, which was significantly greater than that of the normal area (p=0.01). The neuro-pharmacological functional MRI technique using diazepam might be a useful method to identify epileptic foci. (author)

Neuro-pharmacological functional MRI of epilepsy

International Nuclear Information System (INIS)

Kiriyama, Hideki; Makabe, Tetsuo; Tomita, Susumu; Omoto, Takashi; Asari, Shoji; Aihara, Hiroshi; Kinugasa, Kazushi; Nishimoto, Akira; Ito, Takahiko

2000-01-01

We studied patients with epilepsy by neuro-pharmacological functional MRI technique using diazepam. Five normal volunteers and 7 patients with epilepsy were investigated. MRI was performed by a 1.5 T unit (SIGNA Horizon, GE) using the following parameters: TR/TE 5000 msec/80 msec, FA 90 deg, FOV 200 mm, matrix 128 x 128, slice thickness 7 mm. We performed MRI scanning over 5 minutes (2 minutes before and 3 minutes after injection of diazepam) for each 1 session; we scanned 3 sessions for each patient at intervals of 5 minutes. The diazepam was injected rapidly from the antecubital vein. The dose of diazepam was 0.05 mg/kg/injection (total dose was 0.15 mg/kg). The data were analyzed statistically using t-test. Signal change after administration of diazepam was less than 1 to 2% in healthy volunteers. By contrast, in patient with epilepsy, the signal change was almost 3%, which was significantly greater than that of the normal area (p=0.01). The neuro-pharmacological functional MRI technique using diazepam might be a useful method to identify epileptic foci. (author)

Pathophysiological changes detected by MRI within 24 hours after head injury

International Nuclear Information System (INIS)

Nagaoka, Tsukasa; Wakabayashi, Shinichi; Nariai, Tadashi; Ohno, Kikuo; Hirakawa, Kimiyoshi; Fukui, Shinsuke; Takei, Hidenori.

1995-01-01

This report concerns the evaluation of the usefulness of high-field magnetic resonance imaging (MRI) for the diagnosis and prognosis of patients with head injuries. For this purpose we compared the CT and MRI results obtained on 48 such patients. MRI of all cases was taken within 24 hours after head injury using a 1.5-Tesla unit. The sensitivity of the two modalities in the detection of small traumatic lesions was compared. Traumatic lesions of 23 patients (47.9%) were not detected by CT, but they were demonstrated on MRI. Overall, MRI was significantly more sensitive than CT in detecting early and/or subtle traumatic changes of the brain parenchyma (P 1 -WI and T 2 -WI. (B) Corpus callosum lesions with hyperintensity on T 2 -WI were in fact hemorrhagic contusions by signal changes on sequential MRI. The follow-up of chronological changes of a given corpus callosum lesion was essential for confirmation of its pathology. (C) In one case, scratch-like lesions with strong hypointensity on T 1 -WI and hyperintensity on T 2 -WI were clearly demonstrated in the white matter. These observations appeared to indicate axonal damages. (D) Even if initial GCS score is low ( 2 -WI and subsequently disappeared completely. We conclude that performing MRI in the early stage of a head injury is of utility for the understanding of pertinent pathophysiological changes and for predicting outcome. (author)

Functional brain segmentation using inter-subject correlation in fMRI.

Science.gov (United States)

Kauppi, Jukka-Pekka; Pajula, Juha; Niemi, Jari; Hari, Riitta; Tohka, Jussi

2017-05-01

The human brain continuously processes massive amounts of rich sensory information. To better understand such highly complex brain processes, modern neuroimaging studies are increasingly utilizing experimental setups that better mimic daily-life situations. A new exploratory data-analysis approach, functional segmentation inter-subject correlation analysis (FuSeISC), was proposed to facilitate the analysis of functional magnetic resonance (fMRI) data sets collected in these experiments. The method provides a new type of functional segmentation of brain areas, not only characterizing areas that display similar processing across subjects but also areas in which processing across subjects is highly variable. FuSeISC was tested using fMRI data sets collected during traditional block-design stimuli (37 subjects) as well as naturalistic auditory narratives (19 subjects). The method identified spatially local and/or bilaterally symmetric clusters in several cortical areas, many of which are known to be processing the types of stimuli used in the experiments. The method is not only useful for spatial exploration of large fMRI data sets obtained using naturalistic stimuli, but also has other potential applications, such as generation of a functional brain atlases including both lower- and higher-order processing areas. Finally, as a part of FuSeISC, a criterion-based sparsification of the shared nearest-neighbor graph was proposed for detecting clusters in noisy data. In the tests with synthetic data, this technique was superior to well-known clustering methods, such as Ward's method, affinity propagation, and K-means ++. Hum Brain Mapp 38:2643-2665, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Functional MRI in children: clinical and research applications

International Nuclear Information System (INIS)

Leach, James L.; Holland, Scott K.

2010-01-01

Functional MRI has become a critical research tool for evaluating brain function and developmental trajectories in children. Its clinical use in children is becoming more common. This presentation will review the basic underlying physiologic and technical aspects of fMRI, review research applications that have direct clinical relevance, and outline the current clinical uses of this technology. (orig.)

Functional MRI for immediate monitoring stereotactic thalamotomy in a patient with essential tremor

International Nuclear Information System (INIS)

Hesselmann, Volker; Schaaf, Maike; Krug, Barbara; Lackner, Klaus; Maarouf, Mohammed; Hunsche, Stefan; Sturm, Volker; Lasek, Kathrin; Wedekind, Christoph

2006-01-01

The effect of stereotactic thalamotomy was assessed with pre- and postoperative functional magnetic resonance imaging (fMRI) under motor stimulation. A patient with unilateral essential tremor (ET) of the left arm underwent stereotactically guided thalamotomy of the right ventral intermediate thalamic nucleus (VIM). FMRI was done directly before and after surgery on a 1.5-Tesla scanner. The stimulation paradigm was maintainance of the affected arm in an extended position and hand clenching being performed in a block design manner. Statistical analysis was done with Brain Voyager 2000. After thalamotomy the tremor diminished completely. As a difference between the pre- and postoperative fMRI, a significant activation was found in the VIM contralateral to the activation site, adjacent to the inferior olivary nucleus contralateral to the activation site and in the dorsal cingulum. In conclusion, fMRI can detect the functional effect of thalamotomy for tremor treatment. Direct postoperative fMRI provides a sufficient method for estimating the effect of thalamotomy immediately after intervention. The importance of the intermediate thalamic nucleus and the olivary nucleus in tremor generation is supported by our findings. (orig.)

Diffusion-weighted MRI for detecting prostate tumour in men at increased genetic risk

International Nuclear Information System (INIS)

Souza, Nandita M. de; Morgan, Veronica A.; Bancroft, Elizabeth; Sohaib, S. Aslam; Giles, Sharon L.; Kote-Jarai, Zsofia; Castro, Elena; Hazell, Steven; Jafar, Maysam; Eeles, Rosalind

2014-01-01

•Endorectal T2W + DW-MRI is potentially useful for prostate cancer screening.•MRI is specific for detecting prostate cancer in men with increased genetic risk.•Detection of prostate cancer in men at genetically low risk with MRI is limited. Endorectal T2W + DW-MRI is potentially useful for prostate cancer screening. MRI is specific for detecting prostate cancer in men with increased genetic risk. Detection of prostate cancer in men at genetically low risk with MRI is limited. Diffusion-weighted (DW)-MRI is invaluable in detecting prostate cancer. We determined its sensitivity and specificity and established interobserver agreement for detecting tumour in men with a family history of prostate cancer stratified by genetic risk. 51 men with a family history of prostate cancer underwent T2-W + DW-endorectal MRI at 3.0 T. Presence of tumour was noted at right and left apex, mid and basal prostate sextants by 2 independent observers, 1 experienced and the other inexperienced in endorectal MRI. Sensitivity and specificity against a 10-core sampling technique (lateral and medial cores at each level considered together) in men with >2× population risk based on 71 SNP analysis versus those with lower genetic risk scores was established. Interobserver agreement was determined at a subject level. Biopsies indicated cancer in 28 sextants in 13/51 men; 32 of 51 men had twice the population risk (>0.25) based on 71 SNP profiling. Sensitivity/specificity per-subject for patients was 90.0%/86.4% (high-risk) vs. 66.7%/100% (low-risk, observer 1) and 60.0%/86.3% (high-risk) vs. 33.3%/93.8% (low-risk, observer 2) with moderate overall inter-observer agreement (kappa = 0.42). Regional sensitivities/specificities for high-risk vs. low-risk for observer 1 apex 72.2%/100% [33.3%/100%], mid 100%/93.1% [100%/97.3%], base 16.7%/98.3% [0%/100%] and for observer 2 apex 36.4%/98.1% [0%/100%], mid 28.6%/96.5% [100%/100%], base 20%/100% [0%/97.3%] were poorer as they failed to detect

3He-MRI in follow-up of lung transplant recipients

International Nuclear Information System (INIS)

Gast, Klaus Kurt; Zaporozhan, Julia; Ley, Sebastian; Biedermann, Alexander; Knitz, Frank; Eberle, Balthasar; Schmiedeskamp, Joerg; Heussel, Claus-Peter; Mayer, Eckhard; Schreiber, Wolfgang Guenter; Thelen, Manfred; Kauczor, Hans-Ulrich

2004-01-01

The aim of this study was to evaluate the possible contribution of 3 He-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up 3 He-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At 3 He-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and 3 He-MRI was good, although subjective evaluation of 3 He-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The 3 He-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by 3 He-MRI. In 2 of these 5 cases, 3 He-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that 3 He-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies. (orig.)

Comparison of methods for detecting nondeterministic BOLD fluctuation in fMRI.

Science.gov (United States)

Kiviniemi, Vesa; Kantola, Juha-Heikki; Jauhiainen, Jukka; Tervonen, Osmo

2004-02-01

Functional MR imaging (fMRI) has been used in detecting neuronal activation and intrinsic blood flow fluctuations in the brain cortex. This article is aimed for comparing the methods for analyzing the nondeterministic flow fluctuations. Fast Fourier Transformation (FFT), cross correlation (CC), spatial principal component analysis (sPCA), and independent component analysis (sICA) were compared. 15 subjects were imaged at 1.5 T. Three quantitative measures were compared: (1) The number of subjects with identifiable fluctuation, (2) the volume, and (3) mean correlation coefficient (MCC) of the detected voxels. The focusing on cortical structures and the overall usability were qualitatively assessed. sICA was spatially most accurate but time consuming, robust, and detected voxels with high temporal synchrony. The CC and FFT were fast suiting primary screening. The CC detected highest temporal synchrony but the subjective detection for reference vector produced excess variance of the detected volumes. The FFT and sPCA were not spatially accurate and did not detect adequate temporal synchrony of the voxels.

Robust preprocessing for stimulus-based functional MRI of the moving fetus.

Science.gov (United States)

You, Wonsang; Evangelou, Iordanis E; Zun, Zungho; Andescavage, Nickie; Limperopoulos, Catherine

2016-04-01

Fetal motion manifests as signal degradation and image artifact in the acquired time series of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We present a robust preprocessing pipeline to specifically address fetal and placental motion-induced artifacts in stimulus-based fMRI with slowly cycled block design in the living fetus. In the proposed pipeline, motion correction is optimized to the experimental paradigm, and it is performed separately in each phase as well as in each region of interest (ROI), recognizing that each phase and organ experiences different types of motion. To obtain the averaged BOLD signals for each ROI, both misaligned volumes and noisy voxels are automatically detected and excluded, and the missing data are then imputed by statistical estimation based on local polynomial smoothing. Our experimental results demonstrate that the proposed pipeline was effective in mitigating the motion-induced artifacts in stimulus-based fMRI data of the fetal brain and placenta.

Automated detection of multiple sclerosis lesions in serial brain MRI

International Nuclear Information System (INIS)

Llado, Xavier; Ganiler, Onur; Oliver, Arnau; Marti, Robert; Freixenet, Jordi; Valls, Laia; Vilanova, Joan C.; Ramio-Torrenta, Lluis; Rovira, Alex

2012-01-01

Multiple sclerosis (MS) is a serious disease typically occurring in the brain whose diagnosis and efficacy of treatment monitoring are vital. Magnetic resonance imaging (MRI) is frequently used in serial brain imaging due to the rich and detailed information provided. Time-series analysis of images is widely used for MS diagnosis and patient follow-up. However, conventional manual methods are time-consuming, subjective, and error-prone. Thus, the development of automated techniques for the detection and quantification of MS lesions is a major challenge. This paper presents an up-to-date review of the approaches which deal with the time-series analysis of brain MRI for detecting active MS lesions and quantifying lesion load change. We provide a comprehensive reference source for researchers in which several approaches to change detection and quantification of MS lesions are investigated and classified. We also analyze the results provided by the approaches, discuss open problems, and point out possible future trends. Lesion detection approaches are required for the detection of static lesions and for diagnostic purposes, while either quantification of detected lesions or change detection algorithms are needed to follow up MS patients. However, there is not yet a single approach that can emerge as a standard for the clinical practice, automatically providing an accurate MS lesion evolution quantification. Future trends will focus on combining the lesion detection in single studies with the analysis of the change detection in serial MRI. (orig.)

Automated detection of multiple sclerosis lesions in serial brain MRI

Energy Technology Data Exchange (ETDEWEB)

Llado, Xavier; Ganiler, Onur; Oliver, Arnau; Marti, Robert; Freixenet, Jordi [University of Girona, Computer Vision and Robotics Group, Girona (Spain); Valls, Laia [Dr. Josep Trueta University Hospital, Department of Radiology, Girona (Spain); Vilanova, Joan C. [Girona Magnetic Resonance Center, Girona (Spain); Ramio-Torrenta, Lluis [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Multiple Sclerosis and Neuroimmunology Unit, Girona (Spain); Rovira, Alex [Vall d' Hebron University Hospital, Magnetic Resonance Unit, Department of Radiology, Barcelona (Spain)

2012-08-15

Multiple sclerosis (MS) is a serious disease typically occurring in the brain whose diagnosis and efficacy of treatment monitoring are vital. Magnetic resonance imaging (MRI) is frequently used in serial brain imaging due to the rich and detailed information provided. Time-series analysis of images is widely used for MS diagnosis and patient follow-up. However, conventional manual methods are time-consuming, subjective, and error-prone. Thus, the development of automated techniques for the detection and quantification of MS lesions is a major challenge. This paper presents an up-to-date review of the approaches which deal with the time-series analysis of brain MRI for detecting active MS lesions and quantifying lesion load change. We provide a comprehensive reference source for researchers in which several approaches to change detection and quantification of MS lesions are investigated and classified. We also analyze the results provided by the approaches, discuss open problems, and point out possible future trends. Lesion detection approaches are required for the detection of static lesions and for diagnostic purposes, while either quantification of detected lesions or change detection algorithms are needed to follow up MS patients. However, there is not yet a single approach that can emerge as a standard for the clinical practice, automatically providing an accurate MS lesion evolution quantification. Future trends will focus on combining the lesion detection in single studies with the analysis of the change detection in serial MRI. (orig.)

Whole-body muscle MRI to detect myopathies in non-extrapyramidal bent spine syndrome

International Nuclear Information System (INIS)

Ohana, Mickael; Durand, Marie-Christine; Marty, Catherine; Lazareth, Jean-Philippe; Maisonobe, Thierry; Mompoint, Dominique; Carlier, Robert-Yves

2014-01-01

Bent spine syndrome (BSS), defined as an abnormal forward flexion of the trunk resolving in supine position, is usually related to parkinsonism, but can also be encountered in myopathies. This study evaluates whole-body muscle MRI (WB-mMRI) as a tool for detecting underlying myopathy in non-extrapyramidal BSS. Forty-three patients (90 % women; 53-86 years old) with a non-extrapyramidal BSS were prospectively included. All underwent a 1.5-T WB-mMRI and a nerve conduction study. Muscle biopsy was performed if a myopathy could not be eliminated based on clinical examination and all tests. Systematic MRI interpretation focused on peripheral and axial muscle injury; spinal posture and incidental findings were also reported. WB-mMRI was completed for all patients, with 13 muscle biopsies ultimately needed and myopathy revealed as the final etiological diagnosis in five cases (12 %). All biopsy-proven myopathies were detected by the WB-mMRI. Relevant incidental MRI findings were made in seven patients. This study supports WB-mMRI as a sensitive and feasible tool for detecting myopathy in BSS patients. Associated with electroneuromyography, it can better indicate when a muscle biopsy is needed and guide it when required. Rigorous radiological interpretation is mandatory, so as not to miss incidental findings of clinical consequence. (orig.)

Whole-body muscle MRI to detect myopathies in non-extrapyramidal bent spine syndrome

Energy Technology Data Exchange (ETDEWEB)

Ohana, Mickael [Nouvel Hopital Civil - Hopitaux Universitaires de Strasbourg, Service de Radiologie B, Strasbourg (France); Durand, Marie-Christine [AP-HP - Hopital Raymond Poincare, Service de Neurologie, Garches (France); Marty, Catherine; Lazareth, Jean-Philippe [AP-HP - Hopital Raymond Poincare, Service de Rhumatologie, Garches (France); Maisonobe, Thierry [APH-HP - Hopital de la Pitie-Salpetriere, Service de Neuropathologie, Paris (France); Mompoint, Dominique; Carlier, Robert-Yves [AP-HP - Hopital Raymond Poincare, Service de Radiologie, Garches (France)

2014-08-15

Bent spine syndrome (BSS), defined as an abnormal forward flexion of the trunk resolving in supine position, is usually related to parkinsonism, but can also be encountered in myopathies. This study evaluates whole-body muscle MRI (WB-mMRI) as a tool for detecting underlying myopathy in non-extrapyramidal BSS. Forty-three patients (90 % women; 53-86 years old) with a non-extrapyramidal BSS were prospectively included. All underwent a 1.5-T WB-mMRI and a nerve conduction study. Muscle biopsy was performed if a myopathy could not be eliminated based on clinical examination and all tests. Systematic MRI interpretation focused on peripheral and axial muscle injury; spinal posture and incidental findings were also reported. WB-mMRI was completed for all patients, with 13 muscle biopsies ultimately needed and myopathy revealed as the final etiological diagnosis in five cases (12 %). All biopsy-proven myopathies were detected by the WB-mMRI. Relevant incidental MRI findings were made in seven patients. This study supports WB-mMRI as a sensitive and feasible tool for detecting myopathy in BSS patients. Associated with electroneuromyography, it can better indicate when a muscle biopsy is needed and guide it when required. Rigorous radiological interpretation is mandatory, so as not to miss incidental findings of clinical consequence. (orig.)

T1-weighted MRI for the detection of coronary artery plaque haemorrhage

International Nuclear Information System (INIS)

Oei, May Lin; Ozgun, Murat; Seifarth, Harald; Bunck, Alexander; Fischbach, Roman; Heindel, Walter; Maintz, David; Orwat, Stefan; Botnar, Rene

2010-01-01

Hyperintense areas in atherosclerotic plaques on pre-contrast T1-weighted MRI have been shown to correlate with intraplaque haemorrhage. We evaluated the presence of T1 hyperintensity in coronary artery plaques in coronary artery disease (CAD) patients and correlated results with multi-detector computed tomography (MDCT) findings. Fifteen patients with CAD were included. Plaques detected by MDCT were categorised based on their Hounsfield number. T1-weighted inversion recovery (IR) MRI prepared coronary MRI for the detection of plaque and steady-state free-precession coronary MR-angiography for anatomical correlation was performed. After registration of MDCT and MRI, regions of interest were defined on MDCT-visible plaques and in corresponding vessel segments acquired with MRI. MDCT density and MR signal measurement were performed in each plaque. Forty-three plaques were identified with MDCT. With IR-MRI 5/43 (12%) plaques were hyperintense, 2 of which were non-calcified and 3 mixed. Average signal-to-noise and contrast-to-noise ratios of hyperintense plaques were 15.7 and 9.1, compared with 5.6 and 1.2 for hypointense plaques. Hyperintense plaques exhibited a significantly lower CT density than hypointense plaques (63.6 vs. 140.8). There was no correlation of plaque signal intensity with degree of stenosis. T1-weighted IR-MRI may be useful for non-invasive detection and characterisation of intraplaque haemorrhage in coronary artery plaques. (orig.)

Functional imaging of the kidneys with fast MRI techniques

International Nuclear Information System (INIS)

Prasad, Pottumarthi V.; Priatna, Agus

1999-01-01

Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible

MRI-alone radiation therapy planning for prostate cancer: Automatic fiducial marker detection

International Nuclear Information System (INIS)

Ghose, Soumya; Mitra, Jhimli; Rivest-Hénault, David; Fazlollahi, Amir; Fripp, Jurgen; Dowling, Jason A.; Stanwell, Peter; Pichler, Peter; Sun, Jidi; Greer, Peter B.

2016-01-01

Purpose: The feasibility of radiation therapy treatment planning using substitute computed tomography (sCT) generated from magnetic resonance images (MRIs) has been demonstrated by a number of research groups. One challenge with an MRI-alone workflow is the accurate identification of intraprostatic gold fiducial markers, which are frequently used for prostate localization prior to each dose delivery fraction. This paper investigates a template-matching approach for the detection of these seeds in MRI. Methods: Two different gradient echo T1 and T2* weighted MRI sequences were acquired from fifteen prostate cancer patients and evaluated for seed detection. For training, seed templates from manual contours were selected in a spectral clustering manifold learning framework. This aids in clustering “similar” gold fiducial markers together. The marker with the minimum distance to a cluster centroid was selected as the representative template of that cluster during training. During testing, Gaussian mixture modeling followed by a Markovian model was used in automatic detection of the probable candidates. The probable candidates were rigidly registered to the templates identified from spectral clustering, and a similarity metric is computed for ranking and detection. Results: A fiducial detection accuracy of 95% was obtained compared to manual observations. Expert radiation therapist observers were able to correctly identify all three implanted seeds on 11 of the 15 scans (the proposed method correctly identified all seeds on 10 of the 15). Conclusions: An novel automatic framework for gold fiducial marker detection in MRI is proposed and evaluated with detection accuracies comparable to manual detection. When radiation therapists are unable to determine the seed location in MRI, they refer back to the planning CT (only available in the existing clinical framework); similarly, an automatic quality control is built into the automatic software to ensure that all gold

MRI-alone radiation therapy planning for prostate cancer: Automatic fiducial marker detection

Energy Technology Data Exchange (ETDEWEB)

Ghose, Soumya, E-mail: soumya.ghose@case.edu; Mitra, Jhimli [Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106 and CSIRO Health and Biosecurity, The Australian e-Health & Research Centre, Herston, QLD 4029 (Australia); Rivest-Hénault, David; Fazlollahi, Amir; Fripp, Jurgen; Dowling, Jason A. [CSIRO Health and Biosecurity, The Australian e-Health & Research Centre, Herston, QLD 4029 (Australia); Stanwell, Peter [School of health sciences, The University of Newcastle, Newcastle, NSW 2308 (Australia); Pichler, Peter [Department of Radiation Oncology, Cavalry Mater Newcastle Hospital, Newcastle, NSW 2298 (Australia); Sun, Jidi; Greer, Peter B. [School of Mathematical and Physical Sciences, The University of Newcastle, Newcastle, NSW 2308, Australia and Department of Radiation Oncology, Cavalry Mater Newcastle Hospital, Newcastle, NSW 2298 (Australia)

2016-05-15

Purpose: The feasibility of radiation therapy treatment planning using substitute computed tomography (sCT) generated from magnetic resonance images (MRIs) has been demonstrated by a number of research groups. One challenge with an MRI-alone workflow is the accurate identification of intraprostatic gold fiducial markers, which are frequently used for prostate localization prior to each dose delivery fraction. This paper investigates a template-matching approach for the detection of these seeds in MRI. Methods: Two different gradient echo T1 and T2* weighted MRI sequences were acquired from fifteen prostate cancer patients and evaluated for seed detection. For training, seed templates from manual contours were selected in a spectral clustering manifold learning framework. This aids in clustering “similar” gold fiducial markers together. The marker with the minimum distance to a cluster centroid was selected as the representative template of that cluster during training. During testing, Gaussian mixture modeling followed by a Markovian model was used in automatic detection of the probable candidates. The probable candidates were rigidly registered to the templates identified from spectral clustering, and a similarity metric is computed for ranking and detection. Results: A fiducial detection accuracy of 95% was obtained compared to manual observations. Expert radiation therapist observers were able to correctly identify all three implanted seeds on 11 of the 15 scans (the proposed method correctly identified all seeds on 10 of the 15). Conclusions: An novel automatic framework for gold fiducial marker detection in MRI is proposed and evaluated with detection accuracies comparable to manual detection. When radiation therapists are unable to determine the seed location in MRI, they refer back to the planning CT (only available in the existing clinical framework); similarly, an automatic quality control is built into the automatic software to ensure that all gold

Clinical outcome following a low-suspicion multiparametric prostate MRI or benign MRI-guided biopsy to detect prostate cancer

DEFF Research Database (Denmark)

Boesen, Lars; Nørgaard, Nis; Løgager, Vibeke

2017-01-01

follow-up [132/156 (85%)] had decreasing levels of prostate-specific-antigen and could be monitored in primary care. CONCLUSION: A low-suspicion MRI in men with prior negative systematic biopsies has a high negative predictive value in ruling out longer term significant cancer. Therefore, immediate...... repeated biopsies are of limited clinical value and could be avoided even if prostate-specific-antigen levels are persistently elevated.......PURPOSE: To assess the future risk of detecting significant prostate cancer following either a low-suspicion MRI or suspicious MRI with benign MRI-guided biopsies in men with prior negative systematic biopsies. MATERIALS AND METHODS: 289 prospectively enrolled men underwent MRI followed by repeated...

Functional Proton MRI in Emphysematous Rats.

Science.gov (United States)

Bianchi, Andrea; Tibiletti, Marta; Kjørstad, Åsmund; Birk, Gerald; Schad, Lothar R; Stierstorfer, Birgit; Stiller, Detlef; Rasche, Volker

2015-12-01

To demonstrate the feasibility of proton magnetic resonance imaging (MRI) ventilation-related maps in rodents for the evaluation of lung function in the presence of pancreatic porcine elastase (PPE)-induced emphysema. Twelve rats were equally divided into 3 groups: group 1 (no administration of PPE); group 2 (PPE selectively only in the left lung); and group 3 (PPE administered in both lungs). Magnetic resonance imaging (MRI) and computed tomographic (CT) data were acquired at baseline, at 2 weeks and 4 weeks after administration, after which the animals were euthanized. The MRI protocol comprised a golden angle 2-dimensional ultrashort echo time MRI sequence [echo time, 0.343 millisecond (ms); repetition time, 120 ms; 12 slides with thickness, 1 mm; acquisition time, 30 minutes], from which inspiration and expiration images were reconstructed after the extraction of a self-gating signal. Inspiration images were registered to images at expiration, and expansion maps were created by calculating the specific difference in signal intensity. The lungs were segmented, and the mean specific expansion (MSE) calculated as an established surrogate for fractional ventilation. Computed tomographic data provided lung density (peak of the Hounsfield unit histogram, HU_P), whereas histology provided the mean linear intercept for each lung. Two weeks after administration, the control group had a mean MSE in both lungs corresponding to 96% of the baseline. Group 2 had 85% of the baseline, and group 3 had 57%. Considering the PPE-treated lungs alone, a significant reduction in MSE of 27% at 2 weeks and 40% at 4 weeks was found with respect to nontreated lungs. Significant correlations between HU_P and MSE were found at all time points (baseline: r = 0.606, P = 0.0017; 2 weeks: r = 0.837, P ≤ 0.0001; 4 weeks: r = 0.765, P Mean linear intercept values significantly correlated both with MRI MSE (r = -0.770, P The calculated ventilation-related maps showed a reduction of function in

Mandarin functional MRI Language paradigms

OpenAIRE

Ci, He; van Graan, Andre; Gonz?lvez, Gloria; Thompson, Pamela; Hill, Andrea; Duncan, John S.

2016-01-01

Abstract Objective The objective of this study was to implement convenient, fast, and accurate Mandarin task paradigms for functional MRI, and to locate the Chinese language functional areas in frontal and temporal lobes. Materials and Methods Nineteen healthy Chinese volunteers participated in this study, which utilized a block design with four language tasks: auditory naming (AN), picture naming (PN), verbal fluency?character (VFC), and verbal fluency?letter (VFL). All functional images wer...

Functional MRI experiments : acquisition, analysis and interpretation of data

NARCIS (Netherlands)

Ramsey, NF; Hoogduin, H; Jansma, JM

2002-01-01

Functional MRI is widely used to address basic and clinical neuroscience questions. In the key domains of fMRI experiments, i.e. acquisition, processing and analysis, and interpretation of data, developments are ongoing. The main issues are sensitivity for changes in fMRI signal that are associated

Structural and functional MRI in children with renal disease. First experience

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Joergensen, Bettina; Froekiaer, Joergen [Aarhus Univ. Hospital (Denmark). Inst. of Clinical Medicine; Karstoft, Kristian; Pedersen, Michael [Aarhus Univ. Hospital (Denmark). Inst. of Clinical Medicine; Aarhus Univ. Hospital (Denmark). MR Research Centre; Joergensen, Troels Munch [Aarhus Univ. Hospital (Denmark). Dept. of Urology; Rittig, Soeren [Aarhus Univ. Hospital (Denmark). Dept. of Paediatrics

2010-07-01

This MRI study demonstrates our first clinical experiences with structural and functional evaluation in children with renal dysfunction, and communicates our experience with quantitative measurements of renal function compared to reference values found employing radionucleotides. We included renal impaired children who were recruited for clinical radioisotopic GFR measurements (n=8). MRI was performed 2 hours after Cr-EDTA measurements and was conducted using a protocol involving both anatomical/structural sequences and a dynamic contrast-enhanced sequence. Data obtained with the dynamic MRI sequence were processed using the graphical Patlak approach to obtain estimates of GFR. We were able to characterize the intrarenal configuration (cortex, medulla, pelvicalyceal arrangement) in all cases. Functional analyses of dynamic contrast-enhanced MRI revealed an overall underestimation of GFR measured by MRI compared to Cr-EDTPA measures (range: -2% to -43%). We advocate the use of MRI as a single-modality approach in the structural and functional evaluation of impaired kidneys in children, and concurrently, we presented a clinically available strategy for estimations of renal cortical volume and single kidney function. However, the use of MRI contrast agents have recently become controversial in renal patients due to the risk of NSF. (orig.)

Development of functional MRI in gastric cancer

International Nuclear Information System (INIS)

Zhang Lei; Shao Guoliang

2013-01-01

Gastric cancer is one of the most common malignant tumors in digestive tract functional MRI can represent the functional changes of the tumor. DWI not only provides a new way to diagnosis the gastric cancer, but also reflect the pathology changes of the tumor, which has great value to predict the therapeutic effect and prognosis of the tumor. MRS is the only method to test the chemical composition of tissues in live without injury, which has great value in the early diagnosis of gastric tumor and in the research of tumor mechanism. This review is mainly focused on the status and development of functional MRI in gastric cancer. (authors)

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-06-15

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

Comparison of AMI-25 enhanced MRI and helical dynamic CT in the detection of hepatic lesions

International Nuclear Information System (INIS)

Saitou, Kazuhiro; Matsuda, Hiromichi; Fukushima, Hiroaki; Kanzaki, Hiroshi; Hirose, Takashi; Karizaki, Dai; Abe, Kimihiko; Amino, Saburou

1994-01-01

We performed AMI-25 enhanced MRI and helical dynamic CT in 12 cases of hepatic lesions. Nine of these were hepatocellular carcinomas. Two cases were metastatic liver tumors (the primary lesion was gastric in one and the other was gallbladder cancer). One case was suspected to be adenomatous hyperplasia. Thirty-two lesions were detected in T2-weighted SE images before AMI-25 administration, while 46 lesions were detected in AMI-25 enhanced MRI images. In particular, AMI-25 enhanced MRI was superior to plain MRI in lesions less than 10 mm in size. A total of 48 lesions were detected in helical dynamic CT. Although AMI-25 enhanced MRI almost equaled helical dynamic CT in the detection of liver tumors, helical dynamic CT was slightly superior to AMI-25 enhanced MRI in the detection of subphrenic lesions. It was possible to know the hemodynamics in each hepatic lesion by helical dynamic CT. AMI-25 enhanced MRI was useful to know the inclusion of reticuloendothelial system, and that yielded different diagnoses in adenomatous hyperplasia and well differentiated hepatocellular carcinoma. Helical dynamic CT was useful for qualitative diagnosis. Both AMI-25 enhanced MRI and helical dynamic CT contributed to the detection of liver tumor and qualitative diagnosis. (author)

Enhanced subject-specific resting-state network detection and extraction with fast fMRI.

Science.gov (United States)

Akin, Burak; Lee, Hsu-Lei; Hennig, Jürgen; LeVan, Pierre

2017-02-01

Resting-state networks have become an important tool for the study of brain function. An ultra-fast imaging technique that allows to measure brain function, called Magnetic Resonance Encephalography (MREG), achieves an order of magnitude higher temporal resolution than standard echo-planar imaging (EPI). This new sequence helps to correct physiological artifacts and improves the sensitivity of the fMRI analysis. In this study, EPI is compared with MREG in terms of capability to extract resting-state networks. Healthy controls underwent two consecutive resting-state scans, one with EPI and the other with MREG. Subject-level independent component analyses (ICA) were performed separately for each of the two datasets. Using Stanford FIND atlas parcels as network templates, the presence of ICA maps corresponding to each network was quantified in each subject. The number of detected individual networks was significantly higher in the MREG data set than for EPI. Moreover, using short time segments of MREG data, such as 50 seconds, one can still detect and track consistent networks. Fast fMRI thus results in an increased capability to extract distinct functional regions at the individual subject level for the same scan times, and also allow the extraction of consistent networks within shorter time intervals than when using EPI, which is notably relevant for the analysis of dynamic functional connectivity fluctuations. Hum Brain Mapp 38:817-830, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Functional MRI in pre-surgical planning: case study and cautionary ...

African Journals Online (AJOL)

Background. Since its inception almost 20 years ago, functional magnetic resonance imaging (fMRI) has greatly advanced our knowledge of human brain function. Although the clinical applications of fMRI are still limited, there have recently been encouraging advances for its use in pre-operative functional cortical mapping ...

Detection and grading of dAVF: prospects and limitations of 3T MRI.

Science.gov (United States)

Bink, Andrea; Berkefeld, Joachim; Wagner, Marlies; You, Se-Jong; Ackermann, Hanns; Lorenz, Matthias W; Senft, Christian; du Mesnil de Rochemont, Richard

2012-02-01

DSA is currently the criterion standard for the assessment of dural arteriovenous fistulas (dAVF). Recently, evolving MRA techniques have emerged as a non-invasive alternative. The aim of this study is to assess the value of 3 T MRI in detecting and describing dAVF and to determine whether MRI can replace DSA as diagnostic procedure. A total of 19 patients with dAVF and 19 without dAVF underwent the same MRI protocol, including 3D time-of-flight MRA and time-resolved contrast-enhanced MRA. The images were evaluated retrospectively by three independent readers with different levels of experience blinded to clinical information. The readers assessed the presence, the site, the venous drainage and the feeders of dAVF. Sensitivity, specificity, accuracy, intertechnique and interobserver agreements were calculated. DAVF can be detected with high sensitivity, specificity and accuracy by experienced and also by less experienced readers. However, MRI has limitations when used for grading and evaluation of the angioarchitecture of the dAVF. Different experience, the limited resolution of MRI and its inability to selectively display arteries were the reasons for these limitations. With MRI dAVF can be detected reliably. Nevertheless, at present MRI can not fully replace DSA, especially for treatment planning.

Volume based DCE-MRI breast cancer detection with 3D visualization system

International Nuclear Information System (INIS)

Chia, F.K.; Sim, K.S.; Chong, S.S.; Tan, S.T.; Ting, H.Y.; Abbas, S.F.; Omar, S.

2011-01-01

In this paper, a computer aided design auto probing system is presented to detect breast lesions based on Dynamic contrast enhanced Magnetic resonance imaging (DCE-MRI) images. The system is proposed in order to aid the radiologists and doctors in the interpretation of MRI breast images and enhance the detection accuracy. A series of approaches are presented to enhance the detection accuracy and refine the breast region of interest (Roil) automatically. Besides, a semi-quantitative analysis is used to segment the breast lesions from selected breast Roil and classify the detected tumour is whether benign, suspicious or malignant. The entire breast Roil including the detected tumour will display in 3D. The methodology has been applied on 104 sets of digital imaging and communications in medicine (Dico) breast MRI datasets images. The biopsy results are verified by 2 radiologists from Hospital Malaysia. The experimental results are demonstrated the proposed scheme can precisely identify breast cancer regions with 93% accuracy. (author)

Real-time QRS detection using integrated variance for ECG gated cardiac MRI

Directory of Open Access Journals (Sweden)

Schmidt Marcus

2016-09-01

Full Text Available During magnetic resonance imaging (MRI, a patient’s vital signs are required for different purposes. In cardiac MRI (CMR, an electrocardiogram (ECG of the patient is required for triggering the image acquisition process. However, a reliable QRS detection of an ECG signal acquired inside an MRI scanner is a challenging task due to the magnetohydrodynamic (MHD effect which interferes with the ECG. The aim of this work was to develop a reliable QRS detector usable inside the MRI which also fulfills the standards for medical devices (IEC 60601-2-27. Therefore, a novel real-time QRS detector based on integrated variance measurements is presented. The algorithm was trained on ANSI/AAMI EC13 test waveforms and was then applied to two databases with 12-lead ECG signals recorded inside and outside an MRI scanner. Reliable results for both databases were achieved for the ECG signals recorded inside (DBMRI: sensitivity Se = 99.94%, positive predictive value +P = 99.84% and outside (DBInCarT: Se = 99.29%, +P = 99.72% the MRI. Due to the accurate R-peak detection in real-time this can be used for monitoring and triggering in MRI exams.

Sensitivity of enhanced MRI for the detection of breast cancer: new, multicentric, residual, and recurrent

International Nuclear Information System (INIS)

Davis, P.L.; McCarty, K.S. Jr.

1997-01-01

Magnetic resonance imaging (MRI) of the breast brings the advantages of high resolution cross-sectional imaging to breast cancer diagnosis, treatment and research: improved cancer detection, staging, selection of therapy, evaluation of therapeutic response in vivo, detection of recurrence, and even the development of new therapies. Until now breast cancer treatment and research has been impeded by the limited means of evaluating the breast cancer in vivo: primarily clinical palpation and mammography of the breast tumor. A review of the initial studies shows that with the use of paramagnetic contrast agents, MRI has a sensitivity of 96 % for detecting breast cancers. MRI detects multicentric disease with a sensitivity of 98 %, superior to any other modality. The ability of MRI to detect recurrent local breast cancer in the conservatively treated breast is nearly 100 %. MRI is capable of monitoring tumor response to chemotherapy and actually guiding therapeutic interventions such as interstitial laser photocoagulation. (orig.)

Abbreviated protocol for breast MRI: Are multiple sequences needed for cancer detection?

International Nuclear Information System (INIS)

Mango, Victoria L.; Morris, Elizabeth A.; David Dershaw, D.; Abramson, Andrea; Fry, Charles; Moskowitz, Chaya S.; Hughes, Mary; Kaplan, Jennifer; Jochelson, Maxine S.

2015-01-01

Highlights: • Abbreviated breast MR demonstrates high sensitivity for breast carcinoma detection. • Time to perform/interpret the abbreviated exam is shorter than a standard MRI exam. • An abbreviated breast MRI could reduce costs and make MRI screening more available. - Abstract: Objective: To evaluate the ability of an abbreviated breast magnetic resonance imaging (MRI) protocol, consisting of a precontrast T1 weighted (T1W) image and single early post-contrast T1W image, to detect breast carcinoma. Materials and methods: A HIPAA compliant Institutional Review Board approved review of 100 consecutive breast MRI examinations in patients with biopsy proven unicentric breast carcinoma. 79% were invasive carcinomas and 21% were ductal carcinoma in situ. Four experienced breast radiologists, blinded to carcinoma location, history and prior examinations, assessed the abbreviated protocol evaluating only the first post-contrast T1W image, post-processed subtracted first post-contrast and subtraction maximum intensity projection images. Detection and localization of tumor were compared to the standard full diagnostic examination consisting of 13 pre-contrast, post-contrast and post-processed sequences. Results: All 100 cancers were visualized on initial reading of the abbreviated protocol by at least one reader. The mean sensitivity for each sequence was 96% for the first post-contrast sequence, 96% for the first post-contrast subtraction sequence and 93% for the subtraction MIP sequence. Within each sequence, there was no significant difference between the sensitivities among the 4 readers (p = 0.471, p = 0.656, p = 0.139). Mean interpretation time was 44 s (range 11–167 s). The abbreviated imaging protocol could be performed in approximately 10–15 min, compared to 30–40 min for the standard protocol. Conclusion: An abbreviated breast MRI protocol allows detection of breast carcinoma. One pre and post-contrast T1W sequence may be adequate for detecting

Abbreviated protocol for breast MRI: Are multiple sequences needed for cancer detection?

Energy Technology Data Exchange (ETDEWEB)

Mango, Victoria L., E-mail: vlm2125@columbia.edu [Columbia University Medical Center, Herbert Irving Pavilion, 161 Fort Washington Avenue, 10th Floor, New York, NY 10032 (United States); Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Morris, Elizabeth A., E-mail: morrise@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); David Dershaw, D., E-mail: dershawd@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Abramson, Andrea, E-mail: abramsoa@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Fry, Charles, E-mail: charles_fry@nymc.edu [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595 (United States); Moskowitz, Chaya S. [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Hughes, Mary, E-mail: hughesm@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Kaplan, Jennifer, E-mail: kaplanj@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Jochelson, Maxine S., E-mail: jochelsm@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States)

2015-01-15

Highlights: • Abbreviated breast MR demonstrates high sensitivity for breast carcinoma detection. • Time to perform/interpret the abbreviated exam is shorter than a standard MRI exam. • An abbreviated breast MRI could reduce costs and make MRI screening more available. - Abstract: Objective: To evaluate the ability of an abbreviated breast magnetic resonance imaging (MRI) protocol, consisting of a precontrast T1 weighted (T1W) image and single early post-contrast T1W image, to detect breast carcinoma. Materials and methods: A HIPAA compliant Institutional Review Board approved review of 100 consecutive breast MRI examinations in patients with biopsy proven unicentric breast carcinoma. 79% were invasive carcinomas and 21% were ductal carcinoma in situ. Four experienced breast radiologists, blinded to carcinoma location, history and prior examinations, assessed the abbreviated protocol evaluating only the first post-contrast T1W image, post-processed subtracted first post-contrast and subtraction maximum intensity projection images. Detection and localization of tumor were compared to the standard full diagnostic examination consisting of 13 pre-contrast, post-contrast and post-processed sequences. Results: All 100 cancers were visualized on initial reading of the abbreviated protocol by at least one reader. The mean sensitivity for each sequence was 96% for the first post-contrast sequence, 96% for the first post-contrast subtraction sequence and 93% for the subtraction MIP sequence. Within each sequence, there was no significant difference between the sensitivities among the 4 readers (p = 0.471, p = 0.656, p = 0.139). Mean interpretation time was 44 s (range 11–167 s). The abbreviated imaging protocol could be performed in approximately 10–15 min, compared to 30–40 min for the standard protocol. Conclusion: An abbreviated breast MRI protocol allows detection of breast carcinoma. One pre and post-contrast T1W sequence may be adequate for detecting

Validating excised rodent lungs for functional hyperpolarized xenon-129 MRI.

Directory of Open Access Journals (Sweden)

David M L Lilburn

Full Text Available Ex vivo rodent lung models are explored for physiological measurements of respiratory function with hyperpolarized (hp (129Xe MRI. It is shown that excised lung models allow for simplification of the technical challenges involved and provide valuable physiological insights that are not feasible using in vivo MRI protocols. A custom designed breathing apparatus enables MR images of gas distribution on increasing ventilation volumes of actively inhaled hp (129Xe. Straightforward hp (129Xe MRI protocols provide residual lung volume (RV data and permit for spatially resolved tracking of small hp (129Xe probe volumes during the inhalation cycle. Hp (129Xe MRI of lung function in the excised organ demonstrates the persistence of post mortem airway responsiveness to intravenous methacholine challenges. The presented methodology enables physiology of lung function in health and disease without additional regulatory approval requirements and reduces the technical and logistical challenges with hp gas MRI experiments. The post mortem lung functional data can augment histological measurements and should be of interest for drug development studies.

Prenatal detection of microtia by MRI in a fetus with trisomy 22

International Nuclear Information System (INIS)

Milic, Andrea; Blaser, Susan; Robinson, Ashley; Viero, Sandra; Halliday, William; Winsor, Elizabeth; Toi, Ants; Thomas, Micki; Chitayat, David

2006-01-01

Trisomy 22 is a rare chromosomal abnormality infrequently detected prenatally. External ear abnormalities, in particular microtia, are often associated with trisomy 22, but prenatal detection of microtia has not been reported in association with trisomy 22. We report a fetus with trisomy 22, with fetal MRI findings of microtia, craniofacial dysmorphism, and polygyria. Fetal MRI is a useful tool for auricular assessment and might have utility in the prenatal detection of chromosomal abnormalities, especially among fetuses with structural anomalies. (orig.)

Functional imaging of the kidneys with fast MRI techniques

International Nuclear Information System (INIS)

Prasad, P.V.; Priatna, A.

1999-01-01

Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Functional imaging of the kidneys with fast MRI techniques

Energy Technology Data Exchange (ETDEWEB)

Prasad, P.V.; Priatna, A. [AN-234, MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave., Boston, MA (United States)

1999-02-01

Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Novel MRI methodology to detect human whole-brain connectivity changes after ingestion of fructose or glucose

Science.gov (United States)

Tsao, Sinchai; Wilkins, Bryce; Page, Kathleen A.; Singh, Manbir

2012-03-01

A novel MRI protocol has been developed to investigate the differential effects of glucose or fructose consumption on whole-brain functional brain connectivity. A previous study has reported a decrease in the fMRI blood oxygen level dependent (BOLD) signal of the hypothalamus following glucose ingestion, but due to technical limitations, was restricted to a single slice covering the hypothalamus, and thus unable to detect whole-brain connectivity. In another previous study, a protocol was devised to acquire whole-brain fMRI data following food intake, but only after restricting image acquisition to an MR sampling or repetition time (TR) of 20s, making the protocol unsuitable to detect functional connectivity above 0.025Hz. We have successfully implemented a continuous 36-min, 40 contiguous slices, whole-brain BOLD acquisition protocol on a 3T scanner with TR=4.5s to ensure detection of up to 0.1Hz frequencies for whole-brain functional connectivity analysis. Human data were acquired first with ingestion of water only, followed by a glucose or fructose drink within the scanner, without interrupting the scanning. Whole-brain connectivity was analyzed using standard correlation methodology in the 0.01-0.1 Hz range. The correlation coefficient differences between fructose and glucose ingestion among targeted regions were converted to t-scores using the water-only correlation coefficients as a null condition. Results show a dramatic increase in the hypothalamic connectivity to the hippocampus, amygdala, insula, caudate and the nucleus accumben for fructose over glucose. As these regions are known to be key components of the feeding and reward brain circuits, these results suggest a preference for fructose ingestion.

Intraoperative functional MRI as a new approach to monitor deep brain stimulation in Parkinson's disease

International Nuclear Information System (INIS)

Hesselmann, Volker; Sorger, Bettina; Girnus, Ralf; Lasek, Kathrin; Schulte, Oliver; Krug, Barbara; Lackner, Klaus; Maarouf, Mohammad; Sturm, Volker; Wedekind, Christoph; Bunke, Juergen

2004-01-01

This article deals with technical aspects of intraoperative functional magnetic resonance imaging (fMRI) for monitoring the effect of deep brain stimulation (DBS) in a patient with Parkinson's disease. Under motor activation, therapeutic high-frequency stimulation of the subthalamic nucleus was accompanied by an activation decrease in the contralateral primary sensorimotor cortex and the ipsilateral cerebellum. Furthermore, an activation increase in the contralateral basal ganglia and insula region were detected. These findings demonstrate that fMRI constitutes a promising clinical application for investigating brain activity changes induced by DBS. (orig.)

Effective artifact removal in resting state fMRI data improves detection of DMN functional connectivity alteration in Alzheimer’s disease

Directory of Open Access Journals (Sweden)

Ludovica eGriffanti

2015-08-01

Full Text Available Artefact removal from resting state fMRI data is an essential step for a better identification of the resting state networks and the evaluation of their functional connectivity (FC, especially in pathological conditions. There is growing interest in the development of cleaning procedures, especially those not requiring external recordings (data-driven, which are able to remove multiple sources of artefacts. It is important that only inter-subject variability due to the artefacts is removed, preserving the between-subject variability of interest - crucial in clinical applications using clinical scanners to discriminate different pathologies and monitor their staging. In Alzheimer’s disease (AD patients, decreased FC is usually observed in the posterior cingulate cortex within the default mode network (DMN, and this is becoming a possible biomarker for AD. The aim of this study was to compare four different data-driven cleaning procedures (regression of motion parameters; regression of motion parameters, mean white matter and cerebrospinal fluid signal; FMRIB's ICA-based X-noiseifier –FIX- cleanup with soft and aggressive options on data acquired at 1.5T. The approaches were compared using data from 20 elderly healthy subjects and 21 AD patients in a mild stage, in terms of their impact on within-group consistency in FC and ability to detect the typical FC alteration of the DMN in AD patients. Despite an increased within-group consistency across subjects after applying any of the cleaning approaches, only after cleaning with FIX the expected DMN FC alteration in AD was detectable. Our study validates the efficacy of artefact removal even in a relatively small clinical population, and supports the importance of cleaning fMRI data for sensitive detection of FC alterations in a clinical environment.

Implementation of a ferromagnetic detection system in a clinical MRI setting

International Nuclear Information System (INIS)

Orchard, L.J.

2015-01-01

Purpose: To evaluate the implementation of a ferromagnetic detection system (FMDS) into a clinical MRI setting. Materials and methods: One thousand patients were considered for MRI safety screening using an FMDS. Equipment used was a Ferroguard ® Screener (Metrasens Ltd, Malvern, Worcestershire, UK). Fully gowned patients rotated 360° in front of the FMDS in a standardized manner following traditional MRI screening methods (the use of a written questionnaire (Fig. B.1) and verbal interview. Results: Final results included 1032 individual screening events performed in 977 patients. There were 922 (94%) initial passes using the FMDS; 34 (4%) failed initial screens but passed a subsequent screen; 21 (2%) failed the initial and subsequent screens. Thus, including all screening events (n = 1032), there were 956 (93%) true negatives (TN); 21 (2%) false positives (FP) and 55 (5%) true positives (TP). No false negatives (FN) were recorded. Therefore, sensitivity was 100% and specificity was 98%. Conclusion: Implementation and correct usage of an FMDS proved to increase safety within a clinical MRI environment by alerting staff to ferromagnetic items or implants not identified using traditional MRI screening methods. An FMDS should be used as an adjunct to these methods. The information in this study pertains to the specific equipment used in this investigation. - Highlights: • Ferromagnetic detection system sensitivity in this study was 100%. • Ferromagnetic detection system specificity in this study was 98%. • The additional screening procedure had little impact on throughput ie additional time taken was minimal. • Staff training, technique and compliance is important in implementing the screening procedures. • The ferromagnetic detection system identified objects that may have demonstrated projectile, heating or artefact effects

Joint brain connectivity estimation from diffusion and functional MRI data

Science.gov (United States)

Chu, Shu-Hsien; Lenglet, Christophe; Parhi, Keshab K.

2015-03-01

Estimating brain wiring patterns is critical to better understand the brain organization and function. Anatomical brain connectivity models axonal pathways, while the functional brain connectivity characterizes the statistical dependencies and correlation between the activities of various brain regions. The synchronization of brain activity can be inferred through the variation of blood-oxygen-level dependent (BOLD) signal from functional MRI (fMRI) and the neural connections can be estimated using tractography from diffusion MRI (dMRI). Functional connections between brain regions are supported by anatomical connections, and the synchronization of brain activities arises through sharing of information in the form of electro-chemical signals on axon pathways. Jointly modeling fMRI and dMRI data may improve the accuracy in constructing anatomical connectivity as well as functional connectivity. Such an approach may lead to novel multimodal biomarkers potentially able to better capture functional and anatomical connectivity variations. We present a novel brain network model which jointly models the dMRI and fMRI data to improve the anatomical connectivity estimation and extract the anatomical subnetworks associated with specific functional modes by constraining the anatomical connections as structural supports to the functional connections. The key idea is similar to a multi-commodity flow optimization problem that minimizes the cost or maximizes the efficiency for flow configuration and simultaneously fulfills the supply-demand constraint for each commodity. In the proposed network, the nodes represent the grey matter (GM) regions providing brain functionality, and the links represent white matter (WM) fiber bundles connecting those regions and delivering information. The commodities can be thought of as the information corresponding to brain activity patterns as obtained for instance by independent component analysis (ICA) of fMRI data. The concept of information

MRI surveillance for the detection of local recurrence in rectal cancer after transanal endoscopic microsurgery

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Hupkens, Britt J.P.; Martens, Milou H. [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); Maastricht University Medical Center, Department of Surgery, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); Maas, Monique [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); The Netherlands Cancer Institute, Department of Radiology, Amsterdam (Netherlands); Deserno, Willem M.L.L.G. [Laurentius Hospital, Department of Radiology, Roermond (Netherlands); Leijtens, Jeroen W.A. [Laurentius Hospital, Department of Surgery, Roermond (Netherlands); Nelemans, Patty J. [Maastricht University, Department of Epidemiology, Maastricht (Netherlands); Bakers, Frans C.H. [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); Maastricht University Medical Centre, Maastricht (Netherlands); Lambregts, Doenja M.J. [The Netherlands Cancer Institute, Department of Radiology, Amsterdam (Netherlands); Beets, Geerard L. [GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); The Netherlands Cancer Institute, Department of Surgery, Amsterdam (Netherlands); Beets-Tan, Regina G.H. [GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); The Netherlands Cancer Institute, Department of Radiology, Amsterdam (Netherlands)

2017-12-15

To evaluate diagnostic performance of follow-up MRI for detection of local recurrence of rectal cancer after transanal endoscopic microsurgery (TEM). Between January 2006 and February 2014, 81 patients who underwent TEM were included. Two expert readers (R1 and R2), independently evaluated T2-weighted (T2W) MRI and diffusion-weighted (DWI) MRI for the detection of local recurrence, retrospectively, and recorded confidence on a five-point scale. Diagnostic performance of follow-up MRI was assessed using ROC-curve analysis and kappa statistics for the reproducibility between readers. 293 MRIs were performed, 203 included DWI. 18 (22%) patients developed a local recurrence: luminal 11, nodal two and both five. Areas under the curve (AUCs) for local recurrence detection were 0.72 (R1) and 0.80 (R2) for T2W-MRI. For DWI, AUCs were 0.70 (R1) and 0.89 (R2). For nodal recurrence AUCs were 0.72 (R1) and 0.80 (R2) for T2W-MRI. Reproducibility was good for T2W-MRI (κ0.68 for luminal and κ0.71 for nodal recurrence) and moderate for DWI (κ0.57). AUCs and reproducibility for recurrence detection increased during follow-up. Follow-up with MRI after TEM for rectal cancer is feasible. Postoperative changes can be confusing at the first postoperative MRI, but during follow-up diagnostic performance and reproducibility increase. (orig.)

MRI surveillance for the detection of local recurrence in rectal cancer after transanal endoscopic microsurgery

International Nuclear Information System (INIS)

Hupkens, Britt J.P.; Martens, Milou H.; Maas, Monique; Deserno, Willem M.L.L.G.; Leijtens, Jeroen W.A.; Nelemans, Patty J.; Bakers, Frans C.H.; Lambregts, Doenja M.J.; Beets, Geerard L.; Beets-Tan, Regina G.H.

2017-01-01

To evaluate diagnostic performance of follow-up MRI for detection of local recurrence of rectal cancer after transanal endoscopic microsurgery (TEM). Between January 2006 and February 2014, 81 patients who underwent TEM were included. Two expert readers (R1 and R2), independently evaluated T2-weighted (T2W) MRI and diffusion-weighted (DWI) MRI for the detection of local recurrence, retrospectively, and recorded confidence on a five-point scale. Diagnostic performance of follow-up MRI was assessed using ROC-curve analysis and kappa statistics for the reproducibility between readers. 293 MRIs were performed, 203 included DWI. 18 (22%) patients developed a local recurrence: luminal 11, nodal two and both five. Areas under the curve (AUCs) for local recurrence detection were 0.72 (R1) and 0.80 (R2) for T2W-MRI. For DWI, AUCs were 0.70 (R1) and 0.89 (R2). For nodal recurrence AUCs were 0.72 (R1) and 0.80 (R2) for T2W-MRI. Reproducibility was good for T2W-MRI (κ0.68 for luminal and κ0.71 for nodal recurrence) and moderate for DWI (κ0.57). AUCs and reproducibility for recurrence detection increased during follow-up. Follow-up with MRI after TEM for rectal cancer is feasible. Postoperative changes can be confusing at the first postoperative MRI, but during follow-up diagnostic performance and reproducibility increase. (orig.)

Reporting and management of breast lesions detected using MRI

International Nuclear Information System (INIS)

Dall, B.J.G.; Vinnicombe, S.; Gilbert, F.J.

2011-01-01

Magnetic resonance imaging (MRI) is the most accurate technique for diagnosing and delineating the extent of both invasive and in-situ breast cancer and is increasingly being used as part of the preoperative work-up to assess the local extent of disease. It is proving invaluable in providing information that allows successful single-stage surgery. An inevitable consequence of the high sensitivity of MRI is that it will identify additional lesions that may or may not represent significant extra disease. This may complicate and delay the preoperative process. This paper outlines a strategy for managing MRI-detected lesions to optimize the benefits of breast MRI as a local staging tool while minimizing the false-positive diagnoses. It discusses the importance of good technique to reduce the number of indeterminate lesions. Methods to refine the patient pathway to minimize delays are discussed. The format of MRI reporting is discussed in detail as is the usefulness of discussion of cases at multidisciplinary meetings. Illustrative cases are used to clarify the points made.

Multi-flux-transformer MRI detection with an atomic magnetometer.

Science.gov (United States)

Savukov, Igor; Karaulanov, Todor

2014-12-01

Recently, anatomical ultra-low field (ULF) MRI has been demonstrated with an atomic magnetometer (AM). A flux-transformer (FT) has been used for decoupling MRI fields and gradients to avoid their negative effects on AM performance. The field of view (FOV) was limited because of the need to compromise between the size of the FT input coil and MRI sensitivity per voxel. Multi-channel acquisition is a well-known solution to increase FOV without significantly reducing sensitivity. In this paper, we demonstrate twofold FOV increase with the use of three FT input coils. We also show that it is possible to use a single atomic magnetometer and single acquisition channel to acquire three independent MRI signals by applying a frequency-encoding gradient along the direction of the detection array span. The approach can be generalized to more channels and can be critical for imaging applications of non-cryogenic ULF MRI where FOV needs to be large, including head, hand, spine, and whole-body imaging. Copyright © 2014 Elsevier Inc. All rights reserved.

Bladder cancer: utility of MRI in detection of occult muscle-invasive disease

International Nuclear Information System (INIS)

Rosenkrantz, Andrew B.; Mussi, Thais C.; Melamed, Jonathan; Taneja, Samir S.; Huang, William C.

2012-01-01

Background. The presence of muscularis propria invasion by bladder cancer is a key factor in prognosis and treatment decisions, although may be missed by biopsy due to sampling error. MRI has shown potential for detection of muscle invasion but has not specifically been evaluated for this purpose in the setting of bladder cancer patients without evidence of muscle invasion on initial biopsy. Purpose. To evaluate the role of MRI in detection of muscularis propria invasion by bladder cancer following a pathologic diagnosis of non-invasive tumor. Material and Methods. This retrospective study included 23 patients who underwent pelvic MRI following a pathologic diagnosis of bladder cancer without muscularis propria invasion and in whom additional histologic evaluation was performed following MRI. Two radiologists in consensus reviewed T2-weighted images to identify those cases suspicious for muscle invasion on MRI. The radiologists identified whether cases suspicious for invasion demonstrated disruption of the T2-hypointense muscularis layer of the bladder wall, peri-vesical fat stranding, and peri-vesical soft tissue nodularity. Findings were compared with pathologic results obtained after MRI. Results. Suspicion was raised for muscle invasion in eight of 23 cases, four of which exhibited invasion on follow-up pathology. No case without suspicion on MRI exhibited invasion on follow-up pathology. Therefore, sensitivity and specificity were 100% and 79%, respectively. Among individual findings, muscularis disruption on T2WI exhibited sensitivity of 100% and specificity of 79%, peri-vesical fat stranding exhibited sensitivity and specificity of 50% and 84%, and peri-vesical soft tissue nodularity exhibited sensitivity and specificity of 25% and 100%. Conclusion. MRI demonstrated high sensitivity for detection of muscle invasion in cases of bladder cancer without invasion on initial histologic assessment. Muscularis disruption on T2WI appeared to exhibit a better

Bladder cancer: utility of MRI in detection of occult muscle-invasive disease

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Rosenkrantz, Andrew B. [Dept. of Radiology, NYU Langone Medical Center, New York (United States)], E-mail: Andrew.rosenkrantz@nyumc.org; Mussi, Thais C. [Dept. of Radiology, NYU Langone Medical Center, New York (United States); Hospital Israelita Albert Einstein, Sao Paulo (Brazil); Melamed, Jonathan [Dept. of Pathology, NYU Langone Medical Center, New York (United States); Taneja, Samir S.; Huang, William C. [Dept. of Urology, Div. of Urologic Oncology, NYU Langone Medical Center, New York (United States)

2012-07-15

Background. The presence of muscularis propria invasion by bladder cancer is a key factor in prognosis and treatment decisions, although may be missed by biopsy due to sampling error. MRI has shown potential for detection of muscle invasion but has not specifically been evaluated for this purpose in the setting of bladder cancer patients without evidence of muscle invasion on initial biopsy. Purpose. To evaluate the role of MRI in detection of muscularis propria invasion by bladder cancer following a pathologic diagnosis of non-invasive tumor. Material and Methods. This retrospective study included 23 patients who underwent pelvic MRI following a pathologic diagnosis of bladder cancer without muscularis propria invasion and in whom additional histologic evaluation was performed following MRI. Two radiologists in consensus reviewed T2-weighted images to identify those cases suspicious for muscle invasion on MRI. The radiologists identified whether cases suspicious for invasion demonstrated disruption of the T2-hypointense muscularis layer of the bladder wall, peri-vesical fat stranding, and peri-vesical soft tissue nodularity. Findings were compared with pathologic results obtained after MRI. Results. Suspicion was raised for muscle invasion in eight of 23 cases, four of which exhibited invasion on follow-up pathology. No case without suspicion on MRI exhibited invasion on follow-up pathology. Therefore, sensitivity and specificity were 100% and 79%, respectively. Among individual findings, muscularis disruption on T2WI exhibited sensitivity of 100% and specificity of 79%, peri-vesical fat stranding exhibited sensitivity and specificity of 50% and 84%, and peri-vesical soft tissue nodularity exhibited sensitivity and specificity of 25% and 100%. Conclusion. MRI demonstrated high sensitivity for detection of muscle invasion in cases of bladder cancer without invasion on initial histologic assessment. Muscularis disruption on T2WI appeared to exhibit a better

An Automated, Adaptive Framework for Optimizing Preprocessing Pipelines in Task-Based Functional MRI.

Directory of Open Access Journals (Sweden)

Nathan W Churchill

Full Text Available BOLD fMRI is sensitive to blood-oxygenation changes correlated with brain function; however, it is limited by relatively weak signal and significant noise confounds. Many preprocessing algorithms have been developed to control noise and improve signal detection in fMRI. Although the chosen set of preprocessing and analysis steps (the "pipeline" significantly affects signal detection, pipelines are rarely quantitatively validated in the neuroimaging literature, due to complex preprocessing interactions. This paper outlines and validates an adaptive resampling framework for evaluating and optimizing preprocessing choices by optimizing data-driven metrics of task prediction and spatial reproducibility. Compared to standard "fixed" preprocessing pipelines, this optimization approach significantly improves independent validation measures of within-subject test-retest, and between-subject activation overlap, and behavioural prediction accuracy. We demonstrate that preprocessing choices function as implicit model regularizers, and that improvements due to pipeline optimization generalize across a range of simple to complex experimental tasks and analysis models. Results are shown for brief scanning sessions (<3 minutes each, demonstrating that with pipeline optimization, it is possible to obtain reliable results and brain-behaviour correlations in relatively small datasets.

Brain MRI Tumor Detection using Active Contour Model and Local Image Fitting Energy

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Nabizadeh, Nooshin; John, Nigel

2014-03-01

Automatic abnormality detection in Magnetic Resonance Imaging (MRI) is an important issue in many diagnostic and therapeutic applications. Here an automatic brain tumor detection method is introduced that uses T1-weighted images and K. Zhang et. al.'s active contour model driven by local image fitting (LIF) energy. Local image fitting energy obtains the local image information, which enables the algorithm to segment images with intensity inhomogeneities. Advantage of this method is that the LIF energy functional has less computational complexity than the local binary fitting (LBF) energy functional; moreover, it maintains the sub-pixel accuracy and boundary regularization properties. In Zhang's algorithm, a new level set method based on Gaussian filtering is used to implement the variational formulation, which is not only vigorous to prevent the energy functional from being trapped into local minimum, but also effective in keeping the level set function regular. Experiments show that the proposed method achieves high accuracy brain tumor segmentation results.

Human brain functional MRI and DTI visualization with virtual reality.

Science.gov (United States)

Chen, Bin; Moreland, John; Zhang, Jingyu

2011-12-01

Magnetic resonance diffusion tensor imaging (DTI) and functional MRI (fMRI) are two active research areas in neuroimaging. DTI is sensitive to the anisotropic diffusion of water exerted by its macromolecular environment and has been shown useful in characterizing structures of ordered tissues such as the brain white matter, myocardium, and cartilage. The diffusion tensor provides two new types of information of water diffusion: the magnitude and the spatial orientation of water diffusivity inside the tissue. This information has been used for white matter fiber tracking to review physical neuronal pathways inside the brain. Functional MRI measures brain activations using the hemodynamic response. The statistically derived activation map corresponds to human brain functional activities caused by neuronal activities. The combination of these two methods provides a new way to understand human brain from the anatomical neuronal fiber connectivity to functional activities between different brain regions. In this study, virtual reality (VR) based MR DTI and fMRI visualization with high resolution anatomical image segmentation and registration, ROI definition and neuronal white matter fiber tractography visualization and fMRI activation map integration is proposed. Rationale and methods for producing and distributing stereoscopic videos are also discussed.

Functional MRI for planning in neurosurgery

International Nuclear Information System (INIS)

Erb, M.; Saur, R.

2007-01-01

Beside structural images from CT and MR, functional data about localization of brain activations with different tasks becomes more and more important for presurgical planning. With this method, it's possible to depict mainly primary sensory and motoric areas, but also higher functions like speech and memory. To judge this information adequately, one has to be aware of the variability of activation pattern dependent on chosen threshold. Especially, the absence of such activation at a given location does not necessary mean that this area has no function. The reliability of a measurement strongly depends on efficiency of experimental design and cooperation of the patient. Therefore, short and easy tasks which can be performed in a block design should be preferred. Information about localization of functions determined by fMRI can mainly be used for presurgical planning. Intraoperative usage in the navigation system is problematic due to the brain shift. Therefore, intraoperative imaging together with dynamic adaptation using nonlinear deformation algorithms may improve the value of fMRI in the future. (orig.)

Multiparametric MRI in detection and staging of prostate cancer

DEFF Research Database (Denmark)

Boesen, Lars

2017-01-01

progression, the diagnosis and subsequent treatment planning can be challenging. The current diagnostic approach with PSA testing and digital rectal examination followed by transrectal ultrasound biopsies (TRUS-bx) lack in both sensitivity and specificity in PCa detection and offers limited information about......-MRI-targeted biopsies (mp-MRI-bx) under TRUS-guidance of any mp-MRI-suspicious lesion not hit on systematic TRUS-bx. Study II included patients with clinically localised PCa (cT1-T2) determined by digital rectal examination and/or TRUS and scheduled for radical prostatectomy (RP). Mp-MRI was performed prior to RP...... divided by ADCbenign). The ADC measurements (ADCtumour and ADCratio values) were correlated with the Gleason score (GS) from each tumour foci. RESULTS: Eighty-three patients were included in study I. PCa was found in 39/83 (47%) and both the PIRADS summation score and the over-all Likert classification...

Exploring connectivity with large-scale Granger causality on resting-state functional MRI.

Science.gov (United States)

DSouza, Adora M; Abidin, Anas Z; Leistritz, Lutz; Wismüller, Axel

2017-08-01

Large-scale Granger causality (lsGC) is a recently developed, resting-state functional MRI (fMRI) connectivity analysis approach that estimates multivariate voxel-resolution connectivity. Unlike most commonly used multivariate approaches, which establish coarse-resolution connectivity by aggregating voxel time-series avoiding an underdetermined problem, lsGC estimates voxel-resolution, fine-grained connectivity by incorporating an embedded dimension reduction. We investigate application of lsGC on realistic fMRI simulations, modeling smoothing of neuronal activity by the hemodynamic response function and repetition time (TR), and empirical resting-state fMRI data. Subsequently, functional subnetworks are extracted from lsGC connectivity measures for both datasets and validated quantitatively. We also provide guidelines to select lsGC free parameters. Results indicate that lsGC reliably recovers underlying network structure with area under receiver operator characteristic curve (AUC) of 0.93 at TR=1.5s for a 10-min session of fMRI simulations. Furthermore, subnetworks of closely interacting modules are recovered from the aforementioned lsGC networks. Results on empirical resting-state fMRI data demonstrate recovery of visual and motor cortex in close agreement with spatial maps obtained from (i) visuo-motor fMRI stimulation task-sequence (Accuracy=0.76) and (ii) independent component analysis (ICA) of resting-state fMRI (Accuracy=0.86). Compared with conventional Granger causality approach (AUC=0.75), lsGC produces better network recovery on fMRI simulations. Furthermore, it cannot recover functional subnetworks from empirical fMRI data, since quantifying voxel-resolution connectivity is not possible as consequence of encountering an underdetermined problem. Functional network recovery from fMRI data suggests that lsGC gives useful insight into connectivity patterns from resting-state fMRI at a multivariate voxel-resolution. Copyright © 2017 Elsevier B.V. All

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

International Nuclear Information System (INIS)

Krestin, G.P.; Fischbach, R.; Vorreuther, R.; Schulthess, G.K. von

1993-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1993-06-01

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

Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD MRI

Directory of Open Access Journals (Sweden)

Frederic Bauer

2017-12-01

Full Text Available Background/Aims: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI measures tissue oxygenation based on the transverse relaxation rate (R2*. The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. Methods: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI, 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14. BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. Results: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively. Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each. Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each, whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each. Conclusion: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide.

Dynamic MRI-based computer aided diagnostic systems for early detection of kidney transplant rejection: A survey

Science.gov (United States)

Mostapha, Mahmoud; Khalifa, Fahmi; Alansary, Amir; Soliman, Ahmed; Gimel'farb, Georgy; El-Baz, Ayman

2013-10-01

Early detection of renal transplant rejection is important to implement appropriate medical and immune therapy in patients with transplanted kidneys. In literature, a large number of computer-aided diagnostic (CAD) systems using different image modalities, such as ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT), and radionuclide imaging, have been proposed for early detection of kidney diseases. A typical CAD system for kidney diagnosis consists of a set of processing steps including: motion correction, segmentation of the kidney and/or its internal structures (e.g., cortex, medulla), construction of agent kinetic curves, functional parameter estimation, diagnosis, and assessment of the kidney status. In this paper, we survey the current state-of-the-art CAD systems that have been developed for kidney disease diagnosis using dynamic MRI. In addition, the paper addresses several challenges that researchers face in developing efficient, fast and reliable CAD systems for the early detection of kidney diseases.

Detection of early subclinical lung disease in children with cystic fibrosis by lung ventilation imaging with hyperpolarised gas MRI.

Science.gov (United States)

Marshall, Helen; Horsley, Alex; Taylor, Chris J; Smith, Laurie; Hughes, David; Horn, Felix C; Swift, Andrew J; Parra-Robles, Juan; Hughes, Paul J; Norquay, Graham; Stewart, Neil J; Collier, Guilhem J; Teare, Dawn; Cunningham, Steve; Aldag, Ina; Wild, Jim M

2017-08-01

Hyperpolarised 3 He ventilation-MRI, anatomical lung MRI, lung clearance index (LCI), low-dose CT and spirometry were performed on 19 children (6-16 years) with clinically stable mild cystic fibrosis (CF) (FEV 1 >-1.96), and 10 controls. All controls had normal spirometry, MRI and LCI. Ventilation-MRI was the most sensitive method of detecting abnormalities, present in 89% of patients with CF, compared with CT abnormalities in 68%, LCI 47% and conventional MRI 22%. Ventilation defects were present in the absence of CT abnormalities and in patients with normal physiology, including LCI. Ventilation-MRI is thus feasible in young children, highly sensitive and provides additional information about lung structure-function relationships. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

MRI for the detection of calcific features of vertebral haemangioma.

Science.gov (United States)

Bender, Y Y; Böker, S M; Diederichs, G; Walter, T; Wagner, M; Fallenberg, E; Liebig, T; Rickert, M; Hamm, B; Makowski, M R

2017-08-01

To evaluate the diagnostic performance of susceptibility-weighted-magnetic-resonance imaging (SW-MRI) for the detection of vertebral haemangiomas (VHs) compared to T1/T2-weighted MRI sequences, radiographs, and computed tomography (CT). The study was approved by the local ethics review board. An SW-MRI sequence was added to the clinical spine imaging protocol. The image-based diagnosis of 56 VHs in 46 patients was established using T1/T2 MRI in combination with radiography/CT as the reference standard. VHs were assessed based on T1/T2-weighted MRI images alone and in combination with SW-MRI, while radiographs/CT images were excluded from the analysis. Fifty-one of 56 VHs could be identified on T1/T2 MRI images alone, if radiographs/CT images were excluded from analysis. In five cases (9.1%), additional radiographs/CT images were required for the imaging-based diagnosis. If T1/T2 and SW-MRI images were used in combination, all VHs could be diagnosed, without the need for radiography/CT. Size measurements revealed a close correlation between CT and SW-MRI (R 2 =0.94; pspine, as the use of additional CT/radiography can be minimized. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping

Science.gov (United States)

Robinson, Jennifer; Calhoun, Vince

2018-01-01

Purpose To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. Methods A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Results Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. Conclusions The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization. PMID:29351339

Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping.

Science.gov (United States)

Chen, Zikuan; Robinson, Jennifer; Calhoun, Vince

2018-01-01

To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization.

Prospective detection of cortical dysplasia on clinical MRI in pediatric intractable epilepsy

Energy Technology Data Exchange (ETDEWEB)

Radhakrishnan, Rupa; Leach, James L.; Gelfand, Michael J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Mangano, Francesco T. [Cincinnati Children' s Hospital Medical Center, Department of Neurosurgery, Cincinnati, OH (United States); Rozhkov, Leonid; Greiner, Hansel M. [Cincinnati Children' s Hospital Medical Center, Department of Neurology, Comprehensive Epilepsy Treatment Center, Cincinnati, OH (United States); Miles, Lili [Cincinnati Children' s Hospital Medical Center, Department of Pathology, Cincinnati, OH (United States)

2016-09-15

Cortical dysplasia is the most common cause of pediatric refractory epilepsy. MRI detection of epileptogenic lesion is associated with good postsurgical outcome. Additional electrophysiological information is suggested to be helpful in localization of cortical dysplasia. Educational measures were taken to increase the awareness of cortical dysplasia at our institution in the context of a recent International League Against Epilepsy (ILAE 2011) classification of cortical dysplasia. To determine changes in the rate of prospective identification of cortical dysplasia on an initial radiology report and also evaluate the benefit of MRI review as part of a multidisciplinary epilepsy conference in identifying previously overlooked MRI findings. We retrospectively evaluated surgically treated children with refractory epilepsy from 2007 to 2014 with cortical dysplasia on histopathology. We analyzed the initial radiology report, preoperative MRI interpretation at multidisciplinary epilepsy conference and subsequent retrospective MRI review with knowledge of the resection site. We recorded additional electrophysiological data and the presence of lobar concordance with the MRI findings. Of 78 children (44 MRI lesional) evaluated, 18 had initially overlooked MRI findings. Comparing 2007-2010 to 2011-2014, there was improvement in the rate of overlooked findings on the initial radiology report (54% vs. 13% of lesional cases, respectively; P = 0.008). The majority (72%) were identified at a multidisciplinary conference with lobar concordance of findings with at least one additional electrophysiological investigation in 89%. Awareness of current classification schemes of cortical dysplasia and image review in the context of a multidisciplinary conference can lead to improved MRI detection of cortical dysplasia in children. (orig.)

Prospective detection of cortical dysplasia on clinical MRI in pediatric intractable epilepsy

International Nuclear Information System (INIS)

Radhakrishnan, Rupa; Leach, James L.; Gelfand, Michael J.; Mangano, Francesco T.; Rozhkov, Leonid; Greiner, Hansel M.; Miles, Lili

2016-01-01

Cortical dysplasia is the most common cause of pediatric refractory epilepsy. MRI detection of epileptogenic lesion is associated with good postsurgical outcome. Additional electrophysiological information is suggested to be helpful in localization of cortical dysplasia. Educational measures were taken to increase the awareness of cortical dysplasia at our institution in the context of a recent International League Against Epilepsy (ILAE 2011) classification of cortical dysplasia. To determine changes in the rate of prospective identification of cortical dysplasia on an initial radiology report and also evaluate the benefit of MRI review as part of a multidisciplinary epilepsy conference in identifying previously overlooked MRI findings. We retrospectively evaluated surgically treated children with refractory epilepsy from 2007 to 2014 with cortical dysplasia on histopathology. We analyzed the initial radiology report, preoperative MRI interpretation at multidisciplinary epilepsy conference and subsequent retrospective MRI review with knowledge of the resection site. We recorded additional electrophysiological data and the presence of lobar concordance with the MRI findings. Of 78 children (44 MRI lesional) evaluated, 18 had initially overlooked MRI findings. Comparing 2007-2010 to 2011-2014, there was improvement in the rate of overlooked findings on the initial radiology report (54% vs. 13% of lesional cases, respectively; P = 0.008). The majority (72%) were identified at a multidisciplinary conference with lobar concordance of findings with at least one additional electrophysiological investigation in 89%. Awareness of current classification schemes of cortical dysplasia and image review in the context of a multidisciplinary conference can lead to improved MRI detection of cortical dysplasia in children. (orig.)

Methodological principles for optimising functional MRI experiments

International Nuclear Information System (INIS)

Wuestenberg, T.; Giesel, F.L.; Strasburger, H.

2005-01-01

Functional magnetic resonance imaging (fMRI) is one of the most common methods for localising neuronal activity in the brain. Even though the sensitivity of fMRI is comparatively low, the optimisation of certain experimental parameters allows obtaining reliable results. In this article, approaches for optimising the experimental design, imaging parameters and analytic strategies will be discussed. Clinical neuroscientists and interested physicians will receive practical rules of thumb for improving the efficiency of brain imaging experiments. (orig.) [de

Novel fMRI working memory paradigm accurately detects cognitive impairment in multiple sclerosis.

Science.gov (United States)

Nelson, Flavia; Akhtar, Mohammad A; Zúñiga, Edward; Perez, Carlos A; Hasan, Khader M; Wilken, Jeffrey; Wolinsky, Jerry S; Narayana, Ponnada A; Steinberg, Joel L

2017-05-01

Cognitive impairment (CI) cannot be diagnosed by magnetic resonance imaging (MRI). Functional magnetic resonance imaging (fMRI) paradigms, such as the immediate/delayed memory task (I/DMT), detect varying degrees of working memory (WM). Preliminary findings using I/DMT showed differences in blood oxygenation level dependent (BOLD) activation between impaired (MSCI, n = 12) and non-impaired (MSNI, n = 9) multiple sclerosis (MS) patients. The aim of the study was to confirm CI detection based on I/DMT BOLD activation in a larger cohort of MS patients. The role of T2 lesion volume (LV) and Expanded Disability Status Scale (EDSS) in magnitude of BOLD signal was also sought. A total of 50 patients (EDSS mean ( m) = 3.2, disease duration (DD) m = 12 years, and age m = 40 years) underwent the Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) and I/DMT. Working memory activation (WMa) represents BOLD signal during DMT minus signal during IMT. CI was based on MACFIMS. A total of 10 MSNI, 30 MSCI, and 4 borderline patients were included in the analyses. Analysis of variance (ANOVA) showed MSNI had significantly greater WMa than MSCI, in the left prefrontal cortex and left supplementary motor area ( p = 0.032). Regression analysis showed significant inverse correlations between WMa and T2 LV/EDSS in similar areas ( p = 0.005, 0.004, respectively). I/DMT-based BOLD activation detects CI in MS. Larger studies are needed to confirm these findings.

Research progress of BOLD-functional MRI of hepatic encephalopathy

International Nuclear Information System (INIS)

Ni Ling; Zhang Longjiang; Lu Guangming

2013-01-01

Hepatic encephalopathy (HE), characterized by a wide spectrum of clinical manifestations, ranging from behavior abnormality, conscious disorder and even coma, is a consequence of liver dysfunction in both acute and chronic hepatic diseases. Minimal hepatic encephalopathy (MHE) refers to a subgroup of cirrhotic patients without clinical overt hepatic encephalopathy symptoms hut with abnormalities in neuro -cognitive functions. HE/MHE can have a far-reaching impact on quality of life and prognosis. The exact neuropathology mechanism was still unclear. Recently, functional MRI (fMRI) has been increasingly applied for investigating the neuro-pathophysiological mechanism of HE. This paper will review the fMRI research applied on uncovering the neuropathology mechanism of HE. (authors)

MRI for troubleshooting detection of prostate cancer; MRT zur Problemloesung beim Nachweis des Prostatakarzinoms

Energy Technology Data Exchange (ETDEWEB)

Beyersdorff, D.; Hamm, B. [Universitaetsmedizin Berlin, Charite Mitte (Germany)

2005-06-01

Prostate cancer is the most common malignancy in males. Men aged 50 and older are recommended to undergo an annual digital rectal examination (DRE) and determination of prostate-specific antigen (PSA) in serum for early detection. However, prostate biopsies guided by transrectal ultrasound (TRUS) come up negative for cancer in many patients despite having PSA levels above 4 ng/ml. T2-weighted Magnetic Resonance Imaging (MRI) is able to represent the prostate including the surrounding anatomy and depict suspicious areas of low intensity within a high-intensity peripheral zone. MRI has a higher sensitivity for detecting prostate carcinomas than DRE and TRUS in patients having an elevated PSA value and a negative core biopsy. However, its specificity is poor since other abnormalities such as prostatic intraepithelial neoplasia (PIN), prostatitis, scars, or haemmorrhage have a similar MRI appearance. The use of additional techniques such as MR spectroscopy and contrast-enhanced dynamic MRI improves sensitivity, but in particular it improves the specificity of tumor detection. Newly developed biopsy devices enable the performance of targeted biopsies in areas that appear suspicious in the MRI. (orig.)

Functional MRI (fMRI) on lesions in and around the motor and the eloquent cortices

International Nuclear Information System (INIS)

Hara, Yoshie; Nakamura, Mitsugu; Tamura, Shogo; Tamaki, Norihiko; Kitamura, Junji

1999-01-01

From the view point of neurosurgeons, to aim the preoperative localized diagnosis on the motor and the eloquent cortices and postoperative preservation of neurological functions, fMRI was carried for patients with lesions in and around the motor and the eloquent cortices. Even in cases of mechanical oppression or brain edema, the motor and the eloquent cortices are localized on cerebral gyri. In perioperative period, identification and preserving the motor and the eloquent cortices are important for keeping brain function. Twenty six preoperative cases and 3 normal healthy subjects were observed. Exercise enhanced fMRI was performed on 3 normal healthy subjects, fMRI with motor stimulation in 24 cases and fMRI with speech stimulation in 4 cases. The signal intensity increased in all cases responsing to both stimulations. But the signal intensity in 8 cases decreased in some regions by motor stimulation and 1 case by speech stimulation. The decrease of signal intensity in this study seems to be a clinically important finding and it will be required to examine the significance in future. (K.H.)

Impact of real-time virtual sonography, a coordinated sonography and MRI system that uses an image fusion technique, on the sonographic evaluation of MRI-detected lesions of the breast in second-look sonography.

Science.gov (United States)

Nakano, Shogo; Kousaka, Junko; Fujii, Kimihito; Yorozuya, Kyoko; Yoshida, Miwa; Mouri, Yukako; Akizuki, Miwa; Tetsuka, Rie; Ando, Takahito; Fukutomi, Takashi; Oshima, Yukihiko; Kimura, Junko; Ishiguchi, Tsuneo; Arai, Osamu

2012-08-01

The aim of this study was to verify the utility of second-look sonography using real-time virtual sonography (RVS)-a coordinated sonography with an MRI system that uses an image fusion technique with magnetic navigation-on the sonographic evaluation of MRI-detected lesions of the breast. Of the 196 consecutive patients who were examined with breast MRI in our hospital from 2006 to 2009, those patients who underwent second-look sonography to identify MRI-detected lesions were enrolled in this study. MRI was performed using a 1.5-T imager with the patient in a supine position. To assess the efficacy benefits of RVS, the correlations between lesion detection rates, MRI features, distribution, and histopathological classification on second-look sonography using conventional B-mode or RVS were analyzed. Of the 196 patients, 55 (28 %) demonstrated 67 lesions initially detected by MRI, followed by second-look sonography. Of the 67 MRI-detected lesions, 18 (30 %) were identified with second-look sonography using conventional B-mode alone, whereas 60 (90 %) lesions were detected with second-look sonography using RVS (p use of RVS on second-look sonography significantly increases the sonographic detection rate of MRI-detected lesions without operator dependence.

Combination of functional MRI with SAS and MRA

Energy Technology Data Exchange (ETDEWEB)

Sumida, Masayuki; Takeshita, Shinichirou; Kutsuna, Munenori; Akimitsu, Tomohide; Arita, Kazunori; Kurisu, Kaoru [Hiroshima Univ. (Japan). School of Medicine

1999-02-01

For presurgical diagnosis of brain surface, combination of functional MRI (fMRI) with the MR angiography was examined. This method could visualize brain bay, convolution and vein as index of surface. Five normal adults (male, mean age: 28-year-old) and 7 patients with brain tumor on the main locus to surface (male: 4, female: 3, mean age: 52.3-year-old) were studied. fMRI was performed by SPGR method (TR 70, TE 40, flip angle 60, one slice, thickness 10 mm, FOV 20 cm, matrix 128 x 128). The brain surface was visualized by SAS (surface anatomy scanning). SAS was performed by FSE method (TR 6000, TE 200, echo train 16, thickness 20 mm, slice 3, NEX 2). Cortical veins near superior sagittal sinus were visualized by MRA with 2D-TOF method (TR 50, TE 20, flip angle 60, thickness 2 mm, slice 28, NEX 1). These images were superimposed and functional image of peripheral sensorimotor region was evaluated anatomically. In normal adults, high signal was visualized at another side of near sensorimotor region at 8 of 10 sides. All high signal area of fMRI agreed with cortical vein near sensorimotor region that was visualized by MRA. In patients with brain tumor, signal was visualized at another side of sensorimotor region of tumor without 2 cases with palsy. In another side of tumor, signal of fMRI was visualized in 5 of 7 cases. The tumor was visualized as opposite low signal field in SAS. Locational relation between tumor and brain surface and brain function was visualized distinctly by combination of MRA, SAS and MRA. This method could become useful for presurgical diagnosis. (K.H.)

Functional MRI language mapping in pre-surgical epilepsy patients ...

African Journals Online (AJOL)

Background. Functional magnetic resonance imaging (fMRI) is commonly applied to study the neural substrates of language in clinical research and for neurosurgical planning. fMRI language mapping is used to assess language lateralisation, or determine hemispheric dominance, and to localise regions of the brain ...

Morphological and functional imaging in COPD with CT and MRI: present and future

International Nuclear Information System (INIS)

Ley-Zaporozhan, Julia; Ley, Sebastian; Kauczor, Hans-Ulrich

2008-01-01

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. COPD is defined by irreversible airflow obstruction. It is a heterogeneous disease affecting the airways (i.e. chronic bronchitis, airway collapse), the parenchyma (i.e. hyperinflation, air trapping and emphysematous destruction) as well as the vasculature (i.e. hypoxic vasoconstriction, rarefication and pulmonary arterial hypertension) with different severity during the course of the disease. These different aspects of COPD can be best addressed by imaging using a combination of morphological and functional techniques. Three-dimensional high-resolution computed tomography (3D-HRCT) is the technique of choice for morphological imaging of the lung parenchyma and airways. This morphological information is to be accomplished by functional information about perfusion, regional lung mechanics, and ventilation mainly provided by MRI. The comprehensive diagnostic possibilities of CT complemented by MRI will allow for a more sensitive detection, phenotype-driven characterization and dedicated therapy monitoring of COPD as presented in this review. (orig.)

Multiparametric and molecular imaging of breast tumors with MRI and PET/MRI

International Nuclear Information System (INIS)

Pinker, K.; Marino, M.A.; Meyer-Baese, A.; Helbich, T.H.

2016-01-01

Magnetic resonance imaging (MRI) of the breast is an indispensable tool in breast imaging for many indications. Several functional parameters with MRI and positron emission tomography (PET) have been assessed for imaging of breast tumors and their combined application is defined as multiparametric imaging. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the hallmarks of cancer and may provide additional specificity. Multiparametric and molecular imaging of the breast comprises established MRI parameters, such as dynamic contrast-enhanced MRI, diffusion-weighted imaging (DWI), MR proton spectroscopy ( 1 H-MRSI) as well as combinations of radiological and MRI techniques (e.g. PET/CT and PET/MRI) using radiotracers, such as fluorodeoxyglucose (FDG). Multiparametric and molecular imaging of the breast can be performed at different field-strengths (range 1.5-7 T). Emerging parameters comprise novel promising techniques, such as sodium imaging ( 23 Na MRI), phosphorus spectroscopy ( 31 P-MRSI), chemical exchange saturation transfer (CEST) imaging, blood oxygen level-dependent (BOLD) and hyperpolarized MRI as well as various specific radiotracers. Multiparametric and molecular imaging has multiple applications in breast imaging. Multiparametric and molecular imaging of the breast is an evolving field that will enable improved detection, characterization, staging and monitoring for personalized medicine in breast cancer. (orig.) [de

Visualization and quantification of large bowel motility with functional cine-MRI

International Nuclear Information System (INIS)

Buhmann, S.; Wielage, C.; Fischer, T.; Reiser, M.; Lienemann, A.; Kirchhoff, C.; Mussack, T.

2005-01-01

Purpose: to develop and evaluate a method to visualize and quantify large bowel motility using functional cine MRI. Methods: fifteen healthy individuals (8males, 7 females, 20 to 45 years old) with no history or present symptoms of bowel disorders were enrolled in a functional cine MRI examination at 6 a. m. after a starving phase for at least eight hours before and after oral administration of Senna tea (mild stimulating purgative). Two consecutive sets of repeated measurements of the entire abdomen were performed using a 1.5T MRI system with coronal T2-weighted HASTE sequences anatomically adjusted to the course of the large bowel. A navigator technique was used for respiratory gating at the level of the right dorsal diaphragm. The changes in diameter (given in cm) were measured at 5 different locations of the ascending (AC), transverse (TC) and descending colon (DC), and assessed as parameters for the bowel motility. Results: the mean values as a statistical measure for large bowel relaxation were determined. Before ingestion of Senna tea, the mean diameter measured 3.41 cm (ascending colon), 3 cm (transverse colon) and 2.67 cm (descending colon). After the ingestion of Senna tea, the mean diameter increased to 3.69 cm (ascending colon) to 3.4 cm (transverse colon) and to 2.9 cm (descending colon). A statistically significant difference was demonstrated with the Wilcoxon test (level of confidence 0.05). For the determination of dynamic increase, the changes of the statistical scatter amplitude to the mean value were expressed as percentage before and after the ingestion of Senna tea. Thereby, an increase in variation and dynamic range was detected for the AC (112.9%) and DC (100%), but a decrease in the dynamics for the TC (69%). Conclusion: a non-invasive method for the assessment of bowel motility was developed for the first time. The use of functional cine MRI utilizing a prokinetic stimulus allowed visualisation and quantification of large bowel motility

Mutual Connectivity Analysis (MCA) Using Generalized Radial Basis Function Neural Networks for Nonlinear Functional Connectivity Network Recovery in Resting-State Functional MRI.

Science.gov (United States)

DSouza, Adora M; Abidin, Anas Zainul; Nagarajan, Mahesh B; Wismüller, Axel

2016-03-29

We investigate the applicability of a computational framework, called mutual connectivity analysis (MCA), for directed functional connectivity analysis in both synthetic and resting-state functional MRI data. This framework comprises of first evaluating non-linear cross-predictability between every pair of time series prior to recovering the underlying network structure using community detection algorithms. We obtain the non-linear cross-prediction score between time series using Generalized Radial Basis Functions (GRBF) neural networks. These cross-prediction scores characterize the underlying functionally connected networks within the resting brain, which can be extracted using non-metric clustering approaches, such as the Louvain method. We first test our approach on synthetic models with known directional influence and network structure. Our method is able to capture the directional relationships between time series (with an area under the ROC curve = 0.92 ± 0.037) as well as the underlying network structure (Rand index = 0.87 ± 0.063) with high accuracy. Furthermore, we test this method for network recovery on resting-state fMRI data, where results are compared to the motor cortex network recovered from a motor stimulation sequence, resulting in a strong agreement between the two (Dice coefficient = 0.45). We conclude that our MCA approach is effective in analyzing non-linear directed functional connectivity and in revealing underlying functional network structure in complex systems.

Graph-based network analysis of resting-state functional MRI

Directory of Open Access Journals (Sweden)

Jinhui Wang

2010-06-01

Full Text Available In the past decade, resting-state functional MRI (R-fMRI measures of brain activity have attracted considerable attention. Based on changes in the blood oxygen level-dependent signal, R-fMRI offers a novel way to assess the brain’s spontaneous or intrinsic (i.e., task-free activity with both high spatial and temporal resolutions. The properties of both the intra- and inter-regional connectivity of resting-state brain activity have been well documented, promoting our understanding of the brain as a complex network. Specifically, the topological organization of brain networks has been recently studied with graph theory. In this review, we will summarize the recent advances in graph-based brain network analyses of R-fMRI signals, both in typical and atypical populations. Application of these approaches to R-fMRI data has demonstrated non-trivial topological properties of functional networks in the human brain. Among these is the knowledge that the brain’s intrinsic activity is organized as a small-world, highly efficient network, with significant modularity and highly connected hub regions. These network properties have also been found to change throughout normal development, aging and in various pathological conditions. The literature reviewed here suggests that graph-based network analyses are capable of uncovering system-level changes associated with different processes in the resting brain, which could provide novel insights into the understanding of the underlying physiological mechanisms of brain function. We also highlight several potential research topics in the future.

Graph-based network analysis of resting-state functional MRI.

Science.gov (United States)

Wang, Jinhui; Zuo, Xinian; He, Yong

2010-01-01

In the past decade, resting-state functional MRI (R-fMRI) measures of brain activity have attracted considerable attention. Based on changes in the blood oxygen level-dependent signal, R-fMRI offers a novel way to assess the brain's spontaneous or intrinsic (i.e., task-free) activity with both high spatial and temporal resolutions. The properties of both the intra- and inter-regional connectivity of resting-state brain activity have been well documented, promoting our understanding of the brain as a complex network. Specifically, the topological organization of brain networks has been recently studied with graph theory. In this review, we will summarize the recent advances in graph-based brain network analyses of R-fMRI signals, both in typical and atypical populations. Application of these approaches to R-fMRI data has demonstrated non-trivial topological properties of functional networks in the human brain. Among these is the knowledge that the brain's intrinsic activity is organized as a small-world, highly efficient network, with significant modularity and highly connected hub regions. These network properties have also been found to change throughout normal development, aging, and in various pathological conditions. The literature reviewed here suggests that graph-based network analyses are capable of uncovering system-level changes associated with different processes in the resting brain, which could provide novel insights into the understanding of the underlying physiological mechanisms of brain function. We also highlight several potential research topics in the future.

Frequency-dependent changes in the regional amplitude and synchronization of resting-state functional MRI in stroke.

Directory of Open Access Journals (Sweden)

Jianfang Zhu

Full Text Available Resting-state functional magnetic resonance imaging (R-fMRI has been intensively used to assess alterations of inter-regional functional connectivity in patients with stroke, but the regional properties of brain activity in stroke have not yet been fully investigated. Additionally, no study has examined a frequency effect on such regional properties in stroke patients, although this effect has been shown to play important roles in both normal brain functioning and functional abnormalities. Here we utilized R-fMRI to measure the amplitude of low-frequency fluctuations (ALFF and regional homogeneity (ReHo, two major methods for characterizing the regional properties of R-fMRI, in three different frequency bands (slow-5: 0.01-0.027 Hz; slow-4: 0.027-0.73 Hz; and typical band: 0.01-0.1 Hz in 19 stroke patients and 15 healthy controls. Both the ALFF and ReHo analyses revealed changes in brain activity in a number of brain regions, particularly the parietal cortex, in stroke patients compared with healthy controls. Remarkably, the regions with changed activity as detected by the slow-5 band data were more extensive, and this finding was true for both the ALFF and ReHo analyses. These results not only confirm previous studies showing abnormality in the parietal cortex in patients with stroke, but also suggest that R-fMRI studies of stroke should take frequency effects into account when measuring intrinsic brain activity.

Clinical application of functional MRI for chronic epilepsy

International Nuclear Information System (INIS)

Woermann, F.G.; Labudda, K.

2010-01-01

Functional magnetic resonance imaging (fMRI) is frequently used in the presurgical diagnostic procedure of epilepsy patients, in particular for lateralization of speech and memory and for localization of the primary motor cortex to delineate the epileptogenic lesion from eloquent brain areas. fMRI is one of the non-invasive procedures in the presurgical diagnostic process, together with medical history, seizure semiology, neurological examination, interictal and ictal EEG, structural MRI, video EEG monitoring and neuropsychology. This diagnostic sequence leads either to the decision for or against elective epilepsy surgery or to the decision to proceed with invasive diagnostic techniques (Wada test, intra-operative or extra-operative cortical stimulation). It is difficult to evaluate the contribution of the fMRI test in isolation to the validity of the entire diagnostic sequence. Complications such as memory loss and aphasia in temporal lobe resections or paresis after frontal lobe resections are rare and rarely of disastrous extent. This further complicates the evaluation of the clinical relevance of fMRI as a predictive tool. In this article studies which investigated the concordance between fMRI and other diagnostic gold standards will be presented as well as the association between presurgical fMRI and postsurgical morbidity. (orig.) [de

Can MRI replace DMSA in the detection of renal parenchymal defects in children with urinary tract infections?

Energy Technology Data Exchange (ETDEWEB)

Kavanagh, Eoin C.; Ryan, Stephanie; McCourbrey, Siobhan; O' Connor, Rachel; Donoghue, Veronica [Children' s University Hospital, Department of Radiology, Dublin (Ireland); Awan, Atif [Children' s University Hospital, Department of Paediatrics, Dublin (Ireland)

2005-03-01

Renal parenchymal defects may be a consequence of urinary tract infections (UTI) in childhood. MRI is a non-radiation imaging modality compared with DMSA scanning. To compare DMSA with MRI for the detection of renal parenchymal defects in children presenting for radiological investigation after a first UTI. Both DMSA and MRI were performed at the same appointment in 37 children (aged 4 months-13 years; mean 4.5 years) with a history of UTI. Both planar and SPECT DMSA were performed. MRI of the kidneys employed axial and coronal T1-, T2- and fat-saturated T1-weighted (T1-W) sequences. Some children had imaging after IV contrast medium. The coronal fat-saturated T1-W sequence was the best sequence and it detected all the findings on MRI. MRI had a sensitivity of 77% and a specificity of 87% for the detection of a scarred kidney using DMSA as the gold standard. MRI diagnosed pyelonephritis in two children that had been interpreted as scarring on DMSA. Renal MRI using a single, coronal, fat-saturated T1-W sequence is a rapid, accurate and minimally invasive technique for the detection of renal scarring that does not employ ionizing radiation. (orig.)

Can MRI replace DMSA in the detection of renal parenchymal defects in children with urinary tract infections?

International Nuclear Information System (INIS)

Kavanagh, Eoin C.; Ryan, Stephanie; McCourbrey, Siobhan; O'Connor, Rachel; Donoghue, Veronica; Awan, Atif

2005-01-01

Renal parenchymal defects may be a consequence of urinary tract infections (UTI) in childhood. MRI is a non-radiation imaging modality compared with DMSA scanning. To compare DMSA with MRI for the detection of renal parenchymal defects in children presenting for radiological investigation after a first UTI. Both DMSA and MRI were performed at the same appointment in 37 children (aged 4 months-13 years; mean 4.5 years) with a history of UTI. Both planar and SPECT DMSA were performed. MRI of the kidneys employed axial and coronal T1-, T2- and fat-saturated T1-weighted (T1-W) sequences. Some children had imaging after IV contrast medium. The coronal fat-saturated T1-W sequence was the best sequence and it detected all the findings on MRI. MRI had a sensitivity of 77% and a specificity of 87% for the detection of a scarred kidney using DMSA as the gold standard. MRI diagnosed pyelonephritis in two children that had been interpreted as scarring on DMSA. Renal MRI using a single, coronal, fat-saturated T1-W sequence is a rapid, accurate and minimally invasive technique for the detection of renal scarring that does not employ ionizing radiation. (orig.)

HIV Infection Is Associated with Impaired Striatal Function during Inhibition with Normal Cortical Functioning on Functional MRI

NARCIS (Netherlands)

du Plessis, Stéfan; Vink, Matthijs; Joska, John A; Koutsilieri, Eleni; Bagadia, Asif; Stein, Dan J; Emsley, Robin

2015-01-01

The aim of the present study was to investigate the effect of HIV infection on cortical and subcortical regions of the frontal-striatal system involved in the inhibition of voluntary movement. Functional MRI (fMRI) studies suggest that human immunodeficiency virus (HIV) infection is associated with

Methodological Improvements in Combining TMS and Functional MRI

OpenAIRE

Moisa, Marius

2011-01-01

Since 1997, when Bohning and colleagues demonstrated for the first time the feasibility of interleaving transcranial magnetic stimulation (TMS) with blood oxygenation level dependency functional magnetic resonance imaging (BOLD fMRI), this combination became a very promising techniques to study brain connectivity. However, the implementation of a reliable setup for interleaved TMS/fMRI is still technically challenging. In this thesis, I intended to further explore and develop methodological i...

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.)

Functional alterations of V1 cortex in patients with primary open angle glaucoma using functional MRI retinotopic mapping

International Nuclear Information System (INIS)

Shi Linping; Cai Ping; Li Changying; Li Xueqin; Xie Bing; Li Sha; Liu Ting; Chen Xing; Shi Yanshu; Wang Jian

2011-01-01

Objective: To evaluate the functional changes of visual cortex (V1) in patients with primary open angle glaucoma (POAG) by fMRI retinotopic mapping technology. Methods: Fifteen POAG patients and 15 healthy volunteers underwent stimulations with fMRI retinotopic mapping stimulus and contrast-reversing checkerboard patterns stimulus on a Siemens Trio 3.0 T MRI whole-body scanner for functional data collection. Comparisons of V1 fMRI responses between the glaucomatous eyes and the healthy eyes of the patients were carried out using paired samples t-test, while independent samples t-test was used to compare V1 fMRI responses and activations between the healthy eyes of patients and the age-, gender- and side- matched eyes of normal people. Differences of V1 cortical functions and visual functions were analyzed by linear correlation analysis when the glaucomatous and the healthy eyes were simulated individually., Results: (1) V1 fMRI responses of the individually stimulated glaucomatous eyes [(1.24±0.72)%] were weaker than those of the healthy eyes [(2.18±0.93)%] (t=4.757, P 0.05). (2) Differences of V1 cortical functions were negatively correlated with those of visual functions in the individually stimulated glaucomatous and healthy eyes (r=-0.887, P< 0.01). (3) The activated area indexes of V1 cortexes in the healthy eyes from patients (0.72±0.12) were lower than those in the matched eyes of normal people (0.85±0.09) (t=-3.801, P<0.01) . Conclusion: Cortical function impairment was in accordance with visual function impairment in glaucoma. Located and quantified measurement with fMRI retinotopic mapping was a useful method for clinical follow-up and evaluation of functional alteration of glaucomatous visual cortex, and a potentially useful means of studying trans-synaptic degeneration of visual pathways of in vivo glaucoma. (authors)

Functional MRI in human motor control studies and clinical applications

International Nuclear Information System (INIS)

Toma, Keiichiro

2002-01-01

Functional magnetic resonance imaging (fMRI) has been a useful tool for the noninvasive mapping of brain function associated with various motor and cognitive tasks. Because fMRI is based on the blood oxygenation level dependent (BOLD) effect, it does not directly record neural activity. With the fMRI technique, distinguishing BOLD signals creased by cortical projection neurons from those created by intracortical neurons appears to be difficult. Two major experimental designs are used in fMRI studies: block designs and event-related designs. Block-designed fMRI presupposes the steady state of regional cerebral blood flow and has been applied to examinations of brain activation caused by tasks requiring sustained or repetitive movements. By contrast, the more recently developed event-related fMRI with time resolution of a few seconds allows the mapping of brain activation associated with a single movement according to the transient aspects of the hemodynamic response. Increasing evidence suggests that multiple motor areas are engaged in a networked manner to execute various motor acts. In order to understand functional brain maps, it is important that one understands sequential and parallel organizations of anatomical connections between multiple motor areas. In fMRI studies of complex motor tasks, elementary parameters such as movement length, force, velocity, acceleration and frequency should be controlled, because inconsistency in those parameters may alter the extent and intensity of motor cortical activation, confounding interpretation of the findings obtained. In addition to initiation of movements, termination of movements plays an important role in the successful achievement of complex movements. Brain areas exclusively related to the termination of movements have been, for the first time, uncovered with an event-related fMRI technique. We propose the application of fMRI to the elucidation of the pathophysiology of movement disorders, particularly dystonia

Functional MRI in human motor control studies and clinical applications

Energy Technology Data Exchange (ETDEWEB)

Toma, Keiichiro [Kyoto Univ. (Japan). Graduate School of Medicine; Nakai, Toshiharu [Inst. of Biomedical Research and Innovation, Kobe (Japan)

2002-07-01

Functional magnetic resonance imaging (fMRI) has been a useful tool for the noninvasive mapping of brain function associated with various motor and cognitive tasks. Because fMRI is based on the blood oxygenation level dependent (BOLD) effect, it does not directly record neural activity. With the fMRI technique, distinguishing BOLD signals creased by cortical projection neurons from those created by intracortical neurons appears to be difficult. Two major experimental designs are used in fMRI studies: block designs and event-related designs. Block-designed fMRI presupposes the steady state of regional cerebral blood flow and has been applied to examinations of brain activation caused by tasks requiring sustained or repetitive movements. By contrast, the more recently developed event-related fMRI with time resolution of a few seconds allows the mapping of brain activation associated with a single movement according to the transient aspects of the hemodynamic response. Increasing evidence suggests that multiple motor areas are engaged in a networked manner to execute various motor acts. In order to understand functional brain maps, it is important that one understands sequential and parallel organizations of anatomical connections between multiple motor areas. In fMRI studies of complex motor tasks, elementary parameters such as movement length, force, velocity, acceleration and frequency should be controlled, because inconsistency in those parameters may alter the extent and intensity of motor cortical activation, confounding interpretation of the findings obtained. In addition to initiation of movements, termination of movements plays an important role in the successful achievement of complex movements. Brain areas exclusively related to the termination of movements have been, for the first time, uncovered with an event-related fMRI technique. We propose the application of fMRI to the elucidation of the pathophysiology of movement disorders, particularly dystonia

Cortical language activation in aphasia: a functional MRI study

International Nuclear Information System (INIS)

Xu Xiaojun; Zhang Minming; Shang Desheng; Wang Qidong; Luo Benyan

2004-01-01

Objective: To investigate the differences of the underlying neural basis of language processing between normal subjects and aphasics, and to study the feasibility for functional magnetic resonance imaging (fMRI) in examining the cortical language activation in clinical aphasics. Methods: fMRI was used to map language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed word generation task during fMRI scanning, which measured the signal changes associated with regional neural activity induced by the task. These signal changes were processed to statistically generate the activation map that represented the language area. Results: In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions in normal group. In the patient group, however, no activation was showed in the left inferior frontal gyrus whether or not the patient had lesion in the left frontal lobe. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects. Conclusion: The remote effect of focal lesion and functional redistribution or reorganization was found in aphasic patients. fMRI was useful in evaluating the language function in aphasic patients. (authors)

Functional MRI: Genesis, State of the art and the Sequel

International Nuclear Information System (INIS)

Bharath, Rose Dawn

2014-01-01

The last 25 years have seen functional magnetic resonance imaging (fMRI) grow from an interesting experimental imaging technique in the hands of some to a primary investigation of choice in the localization and lateralization of brain function prior to surgery. Developments in the field of computational neurosciences have transformed fMRI analysis from classical subtractive type analysis to dynamic casual modeling, and now to graph theory analysis. This has widened the scope of fMRI, and is therefore finding applications in understanding neural correlates of diseases like autism and Alzheimer's disease, prognostication of diseases like traumatic brain injury, and has the potential to direct therapy. It is unfortunately true that this widened ambit has not received the clinical attention it deserves, probably because fMRI is susceptible to artifacts from skull base and blood products and has reduced sensitivity in patients with vascular malformations, or because a change in medical practice usually lags behind the technological and scientific developments that make it possible. This review focuses on the developmental chronology of fMRI image analysis in the last 25 years with highlights on major milestones like developments in the field of paradigms, analysis methods, resting state fMRI, and functional connectivity. To make the statistical images of brain at work more colorful, the article starts with genesis of fMRI and ends with the hope of a promising bright future. Many inputs for this article are obtained from a series of 103 review articles edited by Bandettini et al., compiling personal experiences of pioneers in this field. Interested readers are encouraged to refer to these for a more complete overview.

Comparison of left ventricular function assessment between echocardiography and MRI in Duchenne muscular dystrophy

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Buddhe, Sujatha; Lewin, Mark; Olson, Aaron; Soriano, Brian D. [University of Washington School of Medicine and Seattle Children' s Hospital, Division of Cardiology, Department of Pediatrics, Seattle, WA (United States); Ferguson, Mark [University of Washington School of Medicine and Seattle Children' s Hospital, Department of Radiology, Seattle, WA (United States)

2016-09-15

Cardiomyopathy in Duchenne muscular dystrophy (DMD) is associated with death in approximately 40% of patients. Echocardiography is routinely used to assess left ventricular (LV) function; however, it has limitations in these patients. We compared echocardiographic measures of cardiac function assessment to cardiac MRI. We included children and young adults with DMD who had MRI performed between January 2010 and July 2015. We measured echocardiographic and MRI parameters of function assessment, including strain. Presence of late gadolinium enhancement (LGE) was assessed by MRI. Subjects were divided into two groups based on MRI left ventricular ejection fraction (LVEF): group I, LVEF ≥55% and group II, LVEF <55%. We included 41 studies in 33 subjects, with 25 in group I and 16 in group II. Mean age of subjects was 13.6 ± 2.8 years and mean duration between echocardiogram and MRI was 7.6 ± 4.1 months. Only 8 of 16 (50%) patients in group II had diminished function on echocardiogram. Echocardiographic images were suboptimal in 16 subjects (39%). Overall, echocardiographic parameters had weak correlation with MRI-derived ejection fraction percentage. MRI-derived myocardial strain assessment has better correlation with MRI ejection fraction as compared to echocardiography-derived strain parameters. Echocardiography-based ventricular functional assessment has weak correlation with MRI parameters in children and young adults with Duchenne muscular dystrophy. While this correlation improves in the subset of subjects with adequate echocardiographic image quality, it remains modest and potentially suboptimal for clinical management. Accordingly, we conclude that MRI should be performed routinely and early in children with DMD, not only for LGE imaging but also for functional assessment. (orig.)

Comparison of left ventricular function assessment between echocardiography and MRI in Duchenne muscular dystrophy

International Nuclear Information System (INIS)

Buddhe, Sujatha; Lewin, Mark; Olson, Aaron; Soriano, Brian D.; Ferguson, Mark

2016-01-01

Cardiomyopathy in Duchenne muscular dystrophy (DMD) is associated with death in approximately 40% of patients. Echocardiography is routinely used to assess left ventricular (LV) function; however, it has limitations in these patients. We compared echocardiographic measures of cardiac function assessment to cardiac MRI. We included children and young adults with DMD who had MRI performed between January 2010 and July 2015. We measured echocardiographic and MRI parameters of function assessment, including strain. Presence of late gadolinium enhancement (LGE) was assessed by MRI. Subjects were divided into two groups based on MRI left ventricular ejection fraction (LVEF): group I, LVEF ≥55% and group II, LVEF <55%. We included 41 studies in 33 subjects, with 25 in group I and 16 in group II. Mean age of subjects was 13.6 ± 2.8 years and mean duration between echocardiogram and MRI was 7.6 ± 4.1 months. Only 8 of 16 (50%) patients in group II had diminished function on echocardiogram. Echocardiographic images were suboptimal in 16 subjects (39%). Overall, echocardiographic parameters had weak correlation with MRI-derived ejection fraction percentage. MRI-derived myocardial strain assessment has better correlation with MRI ejection fraction as compared to echocardiography-derived strain parameters. Echocardiography-based ventricular functional assessment has weak correlation with MRI parameters in children and young adults with Duchenne muscular dystrophy. While this correlation improves in the subset of subjects with adequate echocardiographic image quality, it remains modest and potentially suboptimal for clinical management. Accordingly, we conclude that MRI should be performed routinely and early in children with DMD, not only for LGE imaging but also for functional assessment. (orig.)

MRI of the Breast for the Detection and Assessment of the Size of Ductal Carcinoma in Situ

International Nuclear Information System (INIS)

Kim, Do Youn; Moon, Woo Kyung; Cho, Nariya

2007-01-01

The aim of the study was to compare the accuracy of magnetic resonance imaging (MRI) and mammography for the detection and assessment of the size of ductal carcinoma in situ (DCIS). The preoperative contrast-enhanced MRI and mammography were analyzed in respect of the detection and assessment of the size of DCIS in 72 patients (age range: 30 67 years, mean age: 47 years). The MRI and mammographic measurements were compared with the histopathologic size with using the Pearson's correlation coefficients and the Mann-Whitney u test. We evaluated whether the breast density, the tumor nuclear grade, the presence of comedo necrosis and microinvasion influenced the MRI and mammographic size estimates by using the chi-square test. Of the 72 DCIS lesions, 68 (94%) were detected by MRI and 62 (86%) were detected by mammography. Overall, the Pearson's correlation of the size between MRI and histopathology was 0.786 versus 0.633 between mammography and histopathology (p < 0.001). MRI underestimated the size by more than 1 cm (including false negative examination) in 12 patients (17%), was accurate in 52 patients (72%) and overestimated the size by more than 1 cm in eight patients (11%) whereas mammography underestimated the size in 25 patients (35%), was accurate in 31 patients (43%) and overestimated the size in 16 patients (22%). The MRI, but not the mammography, showed significant correlation for the assessment of the size of tumor in noncomedo DCIS (p < 0.001 vs p = 0.060). The assessment of tumor size by MRI was affected by the nuclear grade (p = 0.008) and the presence of comedo necrosis (p = 0.029), but not by the breast density (p 0.747) or microinvasion (p = 0.093). MRI was more accurate for the detection and assessment of the size of DCIS than mammography

Sensitivity of different MRI sequences in the early detection of melanoma brain metastases

Science.gov (United States)

Breckwoldt, Michael O.; Schwarz, Daniel; Radbruch, Alexander; Enk, Alexander; Bendszus, Martin; Hassel, Jessica; Schlemmer, Heinz-Peter

2018-01-01

Background After the emergence of new MRI techniques such as susceptibility- and diffusion-weighted imaging (SWI and DWI) and because of specific imaging characteristics of melanoma brain metastases (MBM), it is unclear which MRI sequences are most beneficial for detection of MBM. This study was performed to investigate the sensitivity of six clinical MRI sequences in the early detection of MBM. Methods Medical records of all melanoma patients referred to our center between November 2005 and December 2016 were reviewed for presence of MBM. Analysis encompassed six MRI sequences at the time of initial diagnosis of first or new MBM, including non-enhanced T1-weighted (T1w), contrast-enhanced T1w (ceT1w), T2-weighted (T2w), T2w-FLAIR, susceptibility-weighted (SWI) and diffusion-weighted (DWI) MRI. Each lesion was rated with respect to its conspicuity (score from 0—not detectable to 3—clearly visible). Results Of 1210 patients, 217 with MBM were included in the analysis and up to 5 lesions per patient were evaluated. A total of 720 metastases were assessed and all six sequences were available for 425 MBM. Sensitivity (conspicuity ≥2) was 99.7% for ceT1w, 77.0% for FLAIR, 64.7% for SWI, 61.0% for T2w, 56.7% for T1w, and 48.4% for DWI. Thirty-one (7.3%) of 425 lesions were only detectable by ceT1w but no other sequence. Conclusions Contrast-enhanced T1-weighting is more sensitive than all other sequences for detection of MBM. Disruption of the blood-brain-barrier is consistently an earlier sign in MBM than perifocal edema, signal loss on SWI or diffusion restriction. PMID:29596475

Whole-body MRI in comparison to skeletal scintigraphy for detection of skeletal metastases in patients with solid tumors

International Nuclear Information System (INIS)

Ghanem, N.; Altehoefer, C.; Winterer, J.; Schaefer, O.; Bley, T.A.; Langer, M.; Kelly, T.; Moser, E.

2004-01-01

The aim of this study was to compare the diagnostic efficacy of whole-body magnetic resonance imaging (WB-MRI) as a new and rapid examination technique with skeletal scintigraphy for detection of skeletal metastases from solid tumors. In 129 patients with solid malignant tumors, WB-MRI was performed for individual comparison with skeletal scintigraphy. Examinations were performed with the innovative AngioSURF trademark rolling table with integrated phased array surface coil and coronary TIRM sequences for different body regions. The results for WB-MRI and skeletal scintigraphy were concordant in 81% of the cases, whereby both procedures excluded skeletal metastases in 43%. WB-MRI and skeletal scintigraphy demonstrated skeletal metastases in 38% of the cases, whereby WB-MRI provided more comprehensive findings in 45%. In 12% of the cases, skeletal scintigraphy was superior to WB-MRI and in 19% the findings were discordant, whereby WB-MRI detected skeletal metastases in 15 cases which had not been found on skeletal scintigraphy. In nine cases, skeletal scintigraphy was positive when the WB-MRI was negative. In 60% of the cases, WB-MRI evidenced tumor-associated findings. WB-MRI represents a promising new staging technique for detection of skeletal metastases, which is more sensitive in many cases than skeletal scintigraphy in detecting and assessing the extent of skeletal metastases - and tumor-associated findings that are relevant for treatment strategy. (orig.) [de

Functional MRI in the Investigation of Blast-Related Traumatic Brain Injury

Science.gov (United States)

Graner, John; Oakes, Terrence R.; French, Louis M.; Riedy, Gerard

2012-01-01

This review focuses on the application of functional magnetic resonance imaging (fMRI) to the investigation of blast-related traumatic brain injury (bTBI). Relatively little is known about the exact mechanisms of neurophysiological injury and pathological and functional sequelae of bTBI. Furthermore, in mild bTBI, standard anatomical imaging techniques (MRI and computed tomography) generally fail to show focal lesions and most of the symptoms present as subjective clinical functional deficits. Therefore, an objective test of brain functionality has great potential to aid in patient diagnosis and provide a sensitive measurement to monitor disease progression and treatment. The goal of this review is to highlight the relevant body of blast-related TBI literature and present suggestions and considerations in the development of fMRI studies for the investigation of bTBI. The review begins with a summary of recent bTBI publications followed by discussions of various elements of blast-related injury. Brief reviews of some fMRI techniques that focus on mental processes commonly disrupted by bTBI, including working memory, selective attention, and emotional processing, are presented in addition to a short review of resting state fMRI. Potential strengths and weaknesses of these approaches as regards bTBI are discussed. Finally, this review presents considerations that must be made when designing fMRI studies for bTBI populations, given the heterogeneous nature of bTBI and its high rate of comorbidity with other physical and psychological injuries. PMID:23460082

Noninvasive determination of language dominance using functional MRI and near-infrared spectroscopy

International Nuclear Information System (INIS)

Ota, Takahiro; Kamada, Kyousuke; Saito, Nobuhito

2009-01-01

Identification of the language dominant hemisphere is important in cases necessary for partial encephalotomy due to epilepsy and tumor. Functional MRI (fMRI) essentially detects oxy-Hb/deoxy-Hb ratio in the brain region resulted from blood flow change and near-infrared spectroscopy (NIRS), the Hb level change in the tissue, in which the image can be detected by light-receiving proves of NIR-light (780-1500 nm wavelength) irradiated and passed through the tissues. This paper describes the comparison of the two methods for determination of language dominance with reference to that identified by Wada test, a gold standard but inconvenient for both operators and patients. Subjects are 11 brain tumor and 11 epilepsy patients (M 10/F 12, av. age of 36.7 y, 19 right-handed), whose dominances are successfully determined previously by Wada test. fMRI is conducted with 3T machine (General Electric, USA) with phased-array coil in patients receiving various language tasks, and data are processed by Dr. View (Asahi Kasei) to calculate the laterality index for the dominance. NIRS is conducted with Hitachi-Medico ETG-4000 with 695 and 830 nm IR in patients receiving other different language tasks, on whose frontotemporal region of head surface 12-channel probes are equipped. Data are processed by the equipped software to calculate the difference of oxy-Hb change rates between the two hemispheres for the dominance determination. Consistency of fMRI in determining the dominance with Wada test is found 86.3% and of NIRS, 72.7%, which suggests the latter can be only supplementary to the former. However, NIRS is noted to be useful in atypical cases like those with right or bilateral dominance. (K.T.)

Windowed correlation: a suitable tool for providing dynamic fMRI-based functional connectivity neurofeedback on task difficulty.

Directory of Open Access Journals (Sweden)

Anna Zilverstand

Full Text Available The goal of neurofeedback training is to provide participants with relevant information on their ongoing brain processes in order to enable them to change these processes in a meaningful way. Under the assumption of an intrinsic brain-behavior link, neurofeedback can be a tool to guide a participant towards a desired behavioral state, such as a healthier state in the case of patients. Current research in clinical neuroscience regarding the most robust indicators of pathological brain processes in psychiatric and neurological disorders indicates that fMRI-based functional connectivity measures may be among the most important biomarkers of disease. The present study therefore investigated the general potential of providing fMRI neurofeedback based on functional correlations, computed from short-window time course data at the level of single task periods. The ability to detect subtle changes in task performance with block-wise functional connectivity measures was evaluated based on imaging data from healthy participants performing a simple motor task, which was systematically varied along two task dimensions representing two different aspects of task difficulty. The results demonstrate that fMRI-based functional connectivity measures may provide a better indicator for an increase in overall (motor task difficulty than activation level-based measures. Windowed functional correlations thus seem to provide relevant and unique information regarding ongoing brain processes, which is not captured equally well by standard activation level-based neurofeedback measures. Functional connectivity markers, therefore, may indeed provide a valuable tool to enhance and monitor learning within an fMRI neurofeedback setup.

The power of using functional fMRI on small rodents to study brain pharmacology and disease

OpenAIRE

Jonckers, Elisabeth; Shah, Disha; Hamaide, Julie; Verhoye, Marleen; Van der Linden, Annemie

2015-01-01

Abstract: Functional magnetic resonance imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sen...

Parameterized hemodynamic response function data of healthy individuals obtained from resting-state functional MRI in a 7T MRI scanner

Directory of Open Access Journals (Sweden)

D. Rangaprakash

2018-04-01

Full Text Available Functional magnetic resonance imaging (fMRI, being an indirect measure of brain activity, is mathematically defined as a convolution of the unmeasured latent neural signal and the hemodynamic response function (HRF. The HRF is known to vary across the brain and across individuals, and it is modulated by neural as well as non-neural factors. Three parameters characterize the shape of the HRF, which is obtained by performing deconvolution on resting-state fMRI data: response height, time-to-peak and full-width at half-max. The data provided here, obtained from 47 healthy adults, contains these three HRF parameters at every voxel in the brain, as well as HRF parameters from the default-mode network (DMN. In addition, we have provided functional connectivity (FC data from the same DMN regions, obtained for two cases: data with deconvolution (HRF variability minimized and data with no deconvolution (HRF variability corrupted. This would enable researchers to compare regional changes in HRF with corresponding FC differences, to assess the impact of HRF variability on FC. Importantly, the data was obtained in a 7T MRI scanner. While most fMRI studies are conducted at lower field strengths, like 3T, ours is the first study to report HRF data obtained at 7T. FMRI data at ultra-high fields contains larger contributions from small vessels, consequently HRF variability is lower for small vessels at higher field strengths. This implies that findings made from this data would be more conservative than from data acquired at lower fields, such as 3T. Results obtained with this data and further interpretations are available in our recent research study (Rangaprakash et al., in press [1]. This is a valuable dataset for studying HRF variability in conjunction with FC, and for developing the HRF profile in healthy individuals, which would have direct implications for fMRI data analysis, especially resting-state connectivity modeling. This is the first public HRF

Motor function deficits in schizophrenia: an fMRI and VBM study

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Singh, Sadhana; Modi, Shilpi; Kumar, Pawan; Singh, Namita; Khushu, Subash [Institute of Nuclear Medicine and Allied Sciences (INMAS), NMR Research Center, Delhi (India); Goyal, Satnam; Bhatia, Triptish; Deshpande, Smita N. [RML Hospital, PGIMER, New Delhi (India)

2014-05-15

To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session. fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls. The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task. (orig.)

Motor function deficits in schizophrenia: an fMRI and VBM study

International Nuclear Information System (INIS)

Singh, Sadhana; Modi, Shilpi; Kumar, Pawan; Singh, Namita; Khushu, Subash; Goyal, Satnam; Bhatia, Triptish; Deshpande, Smita N.

2014-01-01

To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session. fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls. The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task. (orig.)

Muscle MRI and functional outcome measures in Becker muscular dystrophy.

Science.gov (United States)

Barp, Andrea; Bello, Luca; Caumo, Luca; Campadello, Paola; Semplicini, Claudio; Lazzarotto, Annalisa; Sorarù, Gianni; Calore, Chiara; Rampado, Alessandro; Motta, Raffaella; Stramare, Roberto; Pegoraro, Elena

2017-11-22

Becker muscular dystrophy (BMD) is a neuromuscular disorder allelic to Duchenne muscular dystrophy (DMD), caused by in-frame mutations in the dystrophin gene, and characterized by a clinical progression that is both milder and more heterogeneous than DMD. Muscle magnetic resonance imaging (MRI) has been proposed as biomarker of disease progression in dystrophinopathies. Correlation with clinically meaningful outcome measures such as North Star Ambulatory Assessment (NSAA) and 6 minute walk test (6MWT) is paramount for biomarker qualification. In this study, 51 molecularly confirmed BMD patients (aged 7-69 years) underwent muscle MRI and were evaluated with functional measures (NSAA and 6MWT) at the time of the MRI, and subsequently after one year. We confirmed a pattern of fatty substitution involving mainly the hip extensors and most thigh muscles. Severity of muscle fatty substitution was significantly correlated with specific DMD mutations: in particular, patients with an isolated deletion of exon 48, or deletions bordering exon 51, showed milder involvement. Fat infiltration scores correlated with baseline functional measures, and predicted changes after 1 year. We conclude that in BMD, skeletal muscle MRI not only strongly correlates with motor function, but also helps in predicting functional deterioration within a 12-month time frame.

Accuracy of high-field intraoperative MRI in the detectability of residual tumor in glioma grade IV resections

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Hesselmann, Volker; Mager, Ann-Kathrin [Asklepios-Klinik Nord, Hamburg (Germany). Radiology/Neurologie; Goetz, Claudia; Kremer, Paul [Asklepios-Klinik Nord, Hamburg (Germany). Dept. of Neurosurgery; Detsch, Oliver [Asklepios-Klinik Nord, Hamburg (Germany). Dept. of Anaesthesiology and Intensive Care Medicine; Theisgen, Hannah-Katharina [Universitaetsklinikum Schleswig-Holstein, Kiel (Germany). Dept. of Neurosurgery; Friese, Michael; Gottschalk, Joachim [Asklepios-Klinik Nord, Hamburg (Germany). Dept. of Pathology and Neuropathology; Schwindt, Wolfram [Univ. Hospital Muenster (Germany). Dept. of Clinical Radiology

2017-06-15

To assess the sensitivity/specificity of tumor detection by T1 contrast enhancement in intraoperative MRI (ioMRI) in comparison to histopathological assessment as the gold standard in patients receiving surgical resection of grade IV glioblastoma. 68 patients with a primary or a recurrent glioblastoma scheduled for surgery including fluorescence guidance and neuronavigation were included (mean age: 59 years, 26 female, 42 male patients). The ioMRI after the first resection included transverse FLAIR, DWI, T2-FFE and T1 - 3 d FFE ± GD-DPTA. The second resection was performed whenever residual contrast-enhancing tissue was detected on ioMRI. Resected tissue samples were histopathologically evaluated (gold standard). Additionally, we evaluated the early postoperative MRI scan acquired within 48 h post-OP for remaining enhancing tissue and compared them with the ioMRI scan. In 43 patients ioMRI indicated residual tumorous tissue, which could be confirmed in the histological specimens of the second resection. In 16 (4 with recurrent, 12 with primary glioblastoma) cases, ioMRI revealed truly negative results without residual tumor and follow-up MRI confirmed complete resection. In 7 cases (3 with recurrent, 4 with primary glioblastoma) ioMRI revealed a suspicious result without tumorous tissue in the histopathological workup. In 2 (1 for each group) patients, residual tumorous tissue was detected in spite of negative ioMRI. IoMRI had a sensitivity of 95 % (94 % recurrent and 96 % for primary glioblastoma) and a specificity of 69.5 % (57 % and 75 %, respectively). The positive predictive value was 86 % (84 % for recurrent and 87 % for primary glioblastoma), and the negative predictive value was 88 % (80 % and 92 %, respectively). ioMRI is effective for detecting remaining tumorous tissue after glioma resection. However, scars and leakage of contrast agent can be misleading and limit specificity. Intraoperative MRI (ioMRI) presents with a high sensitivity for residual

Accuracy of high-field intraoperative MRI in the detectability of residual tumor in glioma grade IV resections

International Nuclear Information System (INIS)

Hesselmann, Volker; Mager, Ann-Kathrin; Goetz, Claudia; Kremer, Paul; Detsch, Oliver; Theisgen, Hannah-Katharina; Friese, Michael; Gottschalk, Joachim; Schwindt, Wolfram

2017-01-01

To assess the sensitivity/specificity of tumor detection by T1 contrast enhancement in intraoperative MRI (ioMRI) in comparison to histopathological assessment as the gold standard in patients receiving surgical resection of grade IV glioblastoma. 68 patients with a primary or a recurrent glioblastoma scheduled for surgery including fluorescence guidance and neuronavigation were included (mean age: 59 years, 26 female, 42 male patients). The ioMRI after the first resection included transverse FLAIR, DWI, T2-FFE and T1 - 3 d FFE ± GD-DPTA. The second resection was performed whenever residual contrast-enhancing tissue was detected on ioMRI. Resected tissue samples were histopathologically evaluated (gold standard). Additionally, we evaluated the early postoperative MRI scan acquired within 48 h post-OP for remaining enhancing tissue and compared them with the ioMRI scan. In 43 patients ioMRI indicated residual tumorous tissue, which could be confirmed in the histological specimens of the second resection. In 16 (4 with recurrent, 12 with primary glioblastoma) cases, ioMRI revealed truly negative results without residual tumor and follow-up MRI confirmed complete resection. In 7 cases (3 with recurrent, 4 with primary glioblastoma) ioMRI revealed a suspicious result without tumorous tissue in the histopathological workup. In 2 (1 for each group) patients, residual tumorous tissue was detected in spite of negative ioMRI. IoMRI had a sensitivity of 95 % (94 % recurrent and 96 % for primary glioblastoma) and a specificity of 69.5 % (57 % and 75 %, respectively). The positive predictive value was 86 % (84 % for recurrent and 87 % for primary glioblastoma), and the negative predictive value was 88 % (80 % and 92 %, respectively). ioMRI is effective for detecting remaining tumorous tissue after glioma resection. However, scars and leakage of contrast agent can be misleading and limit specificity. Intraoperative MRI (ioMRI) presents with a high sensitivity for residual

Evaluation of pulmonary arterial morphology and function in cyanotic congenital heart disease by MRI and cine MRI

International Nuclear Information System (INIS)

Hashimoto, Ikuo; Tsubata, Shinichi; Miyazaki, Ayumi; Ichida, Fukiko; Okada, Toshio; Murakami, Arata; Futatsuya, Ryuusuke; Nakajima, Kenshuu; Nakajima, Akio

1993-01-01

Pulmonary arterial anatomy was evaluated by magnetic resonance imaging (MRI), angiography and two-dimensional echocardiography in 20 patients with cyanotic heart disease associated with decreased pulmonary blood flow. Excellent correlation between MRI and angiographic estimates of pulmonary artery diameter was obtained (main pulmonary artery, r=0.87; right pulmonary artery, r=0.96; left pulmonary artery, r=0.95). However, echocardiography could not describe peripheral pulmonary arteries obviously, especially left pulmonary artery. In the assessment of peripheral pulmonary stenosis or obstruction, cine MRI was superior to echocardiography. We conclude that MRI and cine MRI will play an important role in the serial evaluation of pulmonary arterial morphology and function in patients with cyanotic congenital heart disease before and after surgical repair. (author)

Evaluation of pulmonary arterial morphology and function in cyanotic congenital heart disease by MRI and cine MRI

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, Ikuo; Tsubata, Shinichi; Miyazaki, Ayumi; Ichida, Fukiko; Okada, Toshio; Murakami, Arata; Futatsuya, Ryuusuke; Nakajima, Kenshuu; Nakajima, Akio [Toyama Medical and Pharmaceutical Univ. (Japan)

1993-01-01

Pulmonary arterial anatomy was evaluated by magnetic resonance imaging (MRI), angiography and two-dimensional echocardiography in 20 patients with cyanotic heart disease associated with decreased pulmonary blood flow. Excellent correlation between MRI and angiographic estimates of pulmonary artery diameter was obtained (main pulmonary artery, r=0.87; right pulmonary artery, r=0.96; left pulmonary artery, r=0.95). However, echocardiography could not describe peripheral pulmonary arteries obviously, especially left pulmonary artery. In the assessment of peripheral pulmonary stenosis or obstruction, cine MRI was superior to echocardiography. We conclude that MRI and cine MRI will play an important role in the serial evaluation of pulmonary arterial morphology and function in patients with cyanotic congenital heart disease before and after surgical repair. (author).

Functional MRI of the visual cortex and visual testing in patients with previous optic neuritis

DEFF Research Database (Denmark)

Langkilde, Annika Reynberg; Frederiksen, J.L.; Rostrup, Egill

2002-01-01

to both the results of the contrast sensitivity test and to the Snellen visual acuity. Our results indicate that fMRI is a useful method for the study of ON, even in cases where the visual acuity is severely impaired. The reduction in activated volume could be explained as a reduced neuronal input......The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size...... of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed...

Tablet-Based Functional MRI of the Trail Making Test: Effect of Tablet Interaction Mode

Directory of Open Access Journals (Sweden)

Mahta Karimpoor

2017-10-01

Full Text Available The Trail Making Test (TMT is widely used for assessing executive function, frontal lobe abilities, and visual motor skills. Part A of this pen-and-paper test (TMT-A involves linking numbers randomly distributed in space, in ascending order. Part B (TMT-B alternates between linking numbers and letters. TMT-B is more demanding than TMT-A, but the mental processing that supports the performance of this test remains incompletely understood. Functional MRI (fMRI may help to clarify the relationship between TMT performance and brain activity, but providing an environment that supports real-world pen-and-paper interactions during fMRI is challenging. Previously, an fMRI-compatible tablet system was developed for writing and drawing with two modes of interaction: the original cursor-based, proprioceptive approach, and a new mode involving augmented reality to provide visual feedback of hand position (VFHP for enhanced user interaction. This study characterizes the use of the tablet during fMRI of young healthy adults (n = 22, with half of the subjects performing TMT with VFHP and the other half performing TMT without VFHP. Activation maps for both TMT-A and TMT-B performance showed considerable overlap between the two tablet modes, and no statistically differences in brain activity were detected when contrasting TMT-B vs. TMT-A for the two tablet modes. Behavioral results also showed no statistically different interaction effects for TMT-B vs. TMT-A for the two tablet modes. Tablet-based TMT scores showed reasonable convergent validity with those obtained by administering the standard pen-and-paper TMT to the same subjects. Overall, the results suggest that despite the slightly different mechanisms involved for the two modes of tablet interaction, both are suitable for use in fMRI studies involving TMT performance. This study provides information for using tablet-based TMT methods appropriately in future fMRI studies involving patients and healthy

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

International Nuclear Information System (INIS)

Kim, Ah Yeong; Kim, Young Kon; Lee, Min Woo; Park, Min Jung; Hwang, Jiyoung; Lee, Mi Hee; Lee, Jae Won

2012-01-01

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

Detection of osseous metastases of the spine: Comparison of high resolution multi-detector-CT with MRI

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Buhmann, Sonja; Becker, Christoph; Duerr, Hans Roland; Reiser, Maximilian; Baur-Melnyk, Andrea

2009-01-01

Purpose: The aim of the study was to evaluate the diagnostic accuracy of multi-slice-computed tomography (MDCT) for the detection of vertebral metastases in comparison to magnetic resonance imaging (MRI). Materials and methods: In a retrospective analysis, 639 vertebral bodies of 41 patients with various histologically confirmed primary malignancies were analysed. The MDCT-images were acquired on a 16/64-row-MDCT scanner (Siemens Somatom Sensation 16/64). MRI was performed on 1.5 T scanners (SIEMENS Symphony/Sonata). The MDCT- and MRI-images were evaluated separately by two experienced radiologists in a consensus reading. The combination of MDCT and MRI in an expert reading including follow-up examinations and/or histology as well as clinical data served as the gold standard. Results: 201/639 vertebral bodies were defined as metastatically affected by the gold standard. In MDCT 133/201 lesions, in MRI 198/201 lesions were detected. 68 vertebral bodies were false negative in MDCT, whereas 3 false negatives were found in MRI. 3 false positive results were obtained in MDCT, 5 in MRI. Sensitivity was significantly lower for MDCT (66.2%) than for MRI (98.5%) (p < 0.0001). Specificity was not significantly different for both methods (MDCT: 99.3%; MRI: 98.9%). The diagnostic accuracy resulted in 88.8% for MDCT and 98.7% for MRI. Conclusion: Although 16/64-row-MDCT provides excellent image quality and a high spatial resolution in the assessment of bony structures, metastatic lesions without significant bone destruction may be missed. The diagnostic accuracy of MRI proved to be significantly superior to 16/64-row-MDCT for the detection of osseous metastases.

Three-dimensional black-blood contrast-enhanced MRI improves detection of intraluminal thrombi in patients with acute ischaemic stroke.

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Jang, Won; Kwak, Hyo Sung; Chung, Gyung Ho; Hwang, Seung Bae

2018-03-19

This study evaluated the utility of three-dimensional (3D), black-blood (BB), contrast-enhanced, magnetic resonance imaging (MRI) for the detection of intraluminal thrombi in acute stroke patients. Forty-seven patients with acute stroke involving the anterior circulation underwent MRI examination within 6 h of clinical onset. Cerebral angiography was used as the reference standard. In a blinded manner, two neuroradiologists interpreted the following three data sets: (1) diffusion-weighted imaging (DWI) + 3D BB contrast-enhanced MRI; (2) DWI + susceptibility weighted imaging (SWI); (3) DWI + 3D BB contrast-enhanced MRI + SWI. Of these patients, 47 had clots in the middle cerebral artery and four had clots in the anterior cerebral artery. For both observers, the area under the curve (Az) for data sets 1 and 3, which included 3D BB contrast-enhanced MRI, was significantly greater than it was for data set 2, which did not include 3D BB contrast-enhanced MR imaging (observer 1, 0.988 vs 0.904, p = 0.001; observer 2, 0.988 vs 0.894, p = 0.000). Three-dimensional BB contrast-enhanced MRI improves detection of intraluminal thrombi compared to conventional MRI methods in patients with acute ischaemic stroke. • BB contrast-enhanced MRI helps clinicians to assess the intraluminal clot • BB contrast-enhanced MRI improves detection of intraluminal thrombi • BB contrast-enhanced MRI for clot detection has a higher sensitivity.

Methodology for functional MRI of simulated driving.

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Kan, Karen; Schweizer, Tom A; Tam, Fred; Graham, Simon J

2013-01-01

The developed world faces major socioeconomic and medical challenges associated with motor vehicle accidents caused by risky driving. Functional magnetic resonance imaging (fMRI) of individuals using virtual reality driving simulators may provide an important research tool to assess driving safety, based on brain activity and behavior. A fMRI-compatible driving simulator was developed and evaluated in the context of straight driving, turning, and stopping in 16 young healthy adults. Robust maps of brain activity were obtained, including activation of the primary motor cortex, cerebellum, visual cortex, and parietal lobe, with limited head motion (driving is a feasible undertaking.

High-field fMRI unveils orientation columns in humans.

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Yacoub, Essa; Harel, Noam; Ugurbil, Kâmil

2008-07-29

Functional (f)MRI has revolutionized the field of human brain research. fMRI can noninvasively map the spatial architecture of brain function via localized increases in blood flow after sensory or cognitive stimulation. Recent advances in fMRI have led to enhanced sensitivity and spatial accuracy of the measured signals, indicating the possibility of detecting small neuronal ensembles that constitute fundamental computational units in the brain, such as cortical columns. Orientation columns in visual cortex are perhaps the best known example of such a functional organization in the brain. They cannot be discerned via anatomical characteristics, as with ocular dominance columns. Instead, the elucidation of their organization requires functional imaging methods. However, because of insufficient sensitivity, spatial accuracy, and image resolution of the available mapping techniques, thus far, they have not been detected in humans. Here, we demonstrate, by using high-field (7-T) fMRI, the existence and spatial features of orientation- selective columns in humans. Striking similarities were found with the known spatial features of these columns in monkeys. In addition, we found that a larger number of orientation columns are devoted to processing orientations around 90 degrees (vertical stimuli with horizontal motion), whereas relatively similar fMRI signal changes were observed across any given active column. With the current proliferation of high-field MRI systems and constant evolution of fMRI techniques, this study heralds the exciting prospect of exploring unmapped and/or unknown columnar level functional organizations in the human brain.

EKG-based detection of deep brain stimulation in fMRI studies.

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Fiveland, Eric; Madhavan, Radhika; Prusik, Julia; Linton, Renee; Dimarzio, Marisa; Ashe, Jeffrey; Pilitsis, Julie; Hancu, Ileana

2018-04-01

To assess the impact of synchronization errors between the assumed functional MRI paradigm timing and the deep brain stimulation (DBS) on/off cycling using a custom electrocardiogram-based triggering system METHODS: A detector for measuring and predicting the on/off state of cycling deep brain stimulation was developed and tested in six patients in office visits. Three-electrode electrocardiogram measurements, amplified by a commercial bio-amplifier, were used as input for a custom electronics box (e-box). The e-box transformed the deep brain stimulation waveforms into transistor-transistor logic pulses, recorded their timing, and propagated it in time. The e-box was used to trigger task-based deep brain stimulation functional MRI scans in 5 additional subjects; the impact of timing accuracy on t-test values was investigated in a simulation study using the functional MRI data. Following locking to each patient's individual waveform, the e-box was shown to predict stimulation onset with an average absolute error of 112 ± 148 ms, 30 min after disconnecting from the patients. The subsecond accuracy of the e-box in predicting timing onset is more than adequate for our slow varying, 30-/30-s on/off stimulation paradigm. Conversely, the experimental deep brain stimulation onset prediction accuracy in the absence of the e-box, which could be off by as much as 4 to 6 s, could significantly decrease activation strength. Using this detector, stimulation can be accurately synchronized to functional MRI acquisitions, without adding any additional hardware in the MRI environment. Magn Reson Med 79:2432-2439, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

A Functional Iron Oxide Nanoparticles Modified with PLA-PEG-DG as Tumor-Targeted MRI Contrast Agent.

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Xiong, Fei; Hu, Ke; Yu, Haoli; Zhou, Lijun; Song, Lina; Zhang, Yu; Shan, Xiuhong; Liu, Jianping; Gu, Ning

2017-08-01

Tumor targeting could greatly promote the performance of magnetic nanomaterials as MRI (Magnetic Resonance Imaging) agent for tumor diagnosis. Herein, we reported a novel magnetic nanoparticle modified with PLA (poly lactic acid)-PEG (polyethylene glycol)-DG (D-glucosamine) as Tumor-targeted MRI Contrast Agent. In this work, we took use of the D-glucose passive targeting on tumor cells, combining it on PLA-PEG through amide reaction, and then wrapped the PLA-PEG-DG up to the Fe 3 O 4 @OA NPs. The stability and anti phagocytosis of Fe 3 O 4 @OA@PLA-PEG-DG was tested in vitro; the MRI efficiency and toxicity was also detected in vivo. These functional magnetic nanoparticles demonstrated good biocompatibility and stability both in vitro and in vivo. Cell experiments showed that Fe 3 O 4 @OA@PLA-PEG-DG nanoparticles exist good anti phagocytosis and high targetability. In vivo MRI images showed that the contrast effect of Fe 3 O 4 @OA@PLA-PEG-DG nanoparticles prevailed over the commercial non tumor-targeting magnetic nanomaterials MRI agent at a relatively low dose. The DG can validly enhance the tumor-targetting effect of Fe 3 O 4 @OA@PLA-PEG nanoparticle. Maybe MRI agents with DG can hold promise as tumor-targetting development in the future.

Management of breast lesions detectable only on MRI; Abklaerung ausschliesslich MRT-detektierbarer Mammalaesionen

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Siegmann-Luz, K.C.; Bahrs, S.D.; Preibsch, H.; Hattermann, V.; Claussen, C.D. [Universitaetsklinikum Tuebingen (Germany). Abt. Diagnostische und Interventionelle Radiologie

2014-01-15

Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline 'Diagnosis, Therapy, and Follow-Up of Breast Cancer' as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. (orig.)

A urinary biomarker-based risk score correlates with multiparametric MRI for prostate cancer detection.

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Hendriks, Rianne J; van der Leest, Marloes M G; Dijkstra, Siebren; Barentsz, Jelle O; Van Criekinge, Wim; Hulsbergen-van de Kaa, Christina A; Schalken, Jack A; Mulders, Peter F A; van Oort, Inge M

2017-10-01

Prostate cancer (PCa) diagnostics would greatly benefit from more accurate, non-invasive techniques for the detection of clinically significant disease, leading to a reduction of over-diagnosis and over-treatment. The aim of this study was to determine the association between a novel urinary biomarker-based risk score (SelectMDx), multiparametric MRI (mpMRI) outcomes, and biopsy results for PCa detection. This retrospective observational study used data from the validation study of the SelectMDx score, in which urine was collected after digital rectal examination from men undergoing prostate biopsies. A subset of these patients also underwent a mpMRI scan of the prostate. The indications for performing mpMRI were based on persistent clinical suspicion of PCa or local staging after PCa was found upon biopsy. All mpMRI images were centrally reviewed in 2016 by an experienced radiologist blinded for the urine test results and biopsy outcome. The PI-RADS version 2 was used. In total, 172 patients were included for analysis. Hundred (58%) patients had PCa detected upon prostate biopsy, of which 52 (52%) had high-grade disease correlated with a significantly higher SelectMDx score (P < 0.01). The median SelectMDx score was significantly higher in patients with a suspicious significant lesion on mpMRI compared to no suspicion of significant PCa (P < 0.01). For the prediction of mpMRI outcome, the area-under-the-curve of SelectMDx was 0.83 compared to 0.66 for PSA and 0.65 for PCA3. There was a positive association between SelectMDx score and the final PI-RADS grade. There was a statistically significant difference in SelectMDx score between PI-RADS 3 and 4 (P < 0.01) and between PI-RADS 4 and 5 (P < 0.01). The novel urinary biomarker-based SelectMDx score is a promising tool in PCa detection. This study showed promising results regarding the correlation between the SelectMDx score and mpMRI outcomes, outperforming PCA3. Our results suggest that this risk

Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

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Berko, Netanel S; Hay, Arielle; Sterba, Yonit; Wahezi, Dawn; Levin, Terry L

2015-09-01

Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P myositis were 75% and 31%, respectively, with a sensitivity of 40% and specificity of 67%. Compression-strain US

Does preoperative breast MRI significantly impact on initial surgical procedure and re-operation rates in patients with screen-detected invasive lobular carcinoma?

International Nuclear Information System (INIS)

Sinclair, K.; Sakellariou, S.; Dawson, N.; Litherland, J.

2016-01-01

Aim: To investigate whether magnetic resonance imaging (MRI) changes the management of patients with screen-detected invasive lobular carcinoma (ILC). Materials and methods: A retrospective, controlled, single-centre analysis of 138 cases of screen-detected ILC was performed. All patients were assessed by a single multidisciplinary team as to whether preoperative MRI altered the initial management decision or reduced re-operation rates. Results: Forty-three percent of patients had preoperative MRI. MRI guided surgical management in 40.7% patients. Primary mastectomy rates were not significantly different between the MRI and non-MRI groups (32% and 30% respectively, p=0.71). The MRI group had a lower secondary surgery rate (6.8% versus 15.2%); however, the results did not reach statistical significance, and there were no unnecessary mastectomies. Conclusion: MRI can be used appropriately to guide primary surgery in screen-detected ILC cases and affects the initial management decision in 40.7% of patients. It does not significantly affect the overall mastectomy rate or re-operation rates, but reduces the likelihood of the latter. As a result of this review, the authors' local policy for the use of MRI in screen-detected ILC patients has been modified. For patients undergoing mastectomy for ILC, MRI is no longer performed routinely to search for contralateral malignancy as this has no proven added benefit. - Highlights: • Breast magnetic resonance imaging (MRI) allows more accurate tumour assessment and detects additional foci of disease in invasive lobular carcinoma (ILC). • Over the study's 3 year time frame, MRI guided surgical management of 40.7% screen-detected ILC patients scanned. • No statistically significant difference in mastectomy rates between MRI and non MRI groups. • Observed lower re-operation rate (6.8%-v-15.2%) in MRI group not statistically significant. • No MRI benefit for contralateral disease detection in ILC patients for

A novel passive paradigm for functional magnetic resonance imaging (fMRI) to localize brain functions

International Nuclear Information System (INIS)

Gasser, T.; Sandalcioglu, I.E.; Skwarek, V.; Gizewski, E.; Stolke, D.; Hans, V.

2003-01-01

The design of a shielded stimulation-device for electrical stimulation of peripheral nerves in the MRI-environment as passive fMRI-paradigm is content of this study. Especially the technical aspects and selection criteria of the stimulation-parameters are discussed. The clinical value for neurosurgical patients is outlined by supplying data from clinical studies, evaluating this novel paradigm. Thus neurosurgeons are supplied with superior information about functional anatomy, therefore being able to preserve functionally relevant brain-structures. (orig.) [de

The effect of fMRI task combinations on determining the hemispheric dominance of language functions

International Nuclear Information System (INIS)

Niskanen, Eini; Koenoenen, Mervi; Villberg, Ville; Aeikiae, Marja; Nissi, Mikko; Ranta-aho, Perttu; Karjalainen, Pasi; Saeisaenen, Laura; Mervaala, Esa; Kaelviaeinen, Reetta; Vanninen, Ritva

2012-01-01

The purpose of this study is to establish the most suitable combination of functional magnetic resonance imaging (fMRI) language tasks for clinical use in determining language dominance and to define the variability in laterality index (LI) and activation power between different combinations of language tasks. Activation patterns of different fMRI analyses of five language tasks (word generation, responsive naming, letter task, sentence comprehension, and word pair) were defined for 20 healthy volunteers (16 right-handed). LIs and sums of T values were calculated for each task separately and for four combinations of tasks in predefined regions of interest. Variability in terms of activation power and lateralization was defined in each analysis. In addition, the visual assessment of lateralization of language functions based on the individual fMRI activation maps was conducted by an experienced neuroradiologist. A combination analysis of word generation, responsive naming, and sentence comprehension was the most suitable in terms of activation power, robustness to detect essential language areas, and scanning time. In general, combination analyses of the tasks provided higher overall activation levels than single tasks and reduced the number of outlier voxels disturbing the calculation of LI. A combination of auditory and visually presented tasks that activate different aspects of language functions with sufficient activation power may be a useful task battery for determining language dominance in patients. (orig.)

The effect of fMRI task combinations on determining the hemispheric dominance of language functions

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Niskanen, Eini [University of Eastern Finland, Department of Applied Physics, Kuopio (Finland); Kuopio University Hospital, Department of Clinical Radiology, Kuopio (Finland); Koenoenen, Mervi [Kuopio University Hospital, Department of Clinical Radiology, Kuopio (Finland); Kuopio University Hospital, Department of Clinical Neurophysiology, Kuopio (Finland); Villberg, Ville; Aeikiae, Marja [Kuopio University Hospital, Department of Neurology, Kuopio (Finland); Nissi, Mikko; Ranta-aho, Perttu; Karjalainen, Pasi [University of Eastern Finland, Department of Applied Physics, Kuopio (Finland); Saeisaenen, Laura; Mervaala, Esa [Kuopio University Hospital, Department of Clinical Neurophysiology, Kuopio (Finland); University of Eastern Finland, Institute of Clinical Medicine, Clinical Neurophysiology, Kuopio (Finland); Kaelviaeinen, Reetta [Kuopio University Hospital, Department of Neurology, Kuopio (Finland); University of Eastern Finland, Institute of Clinical Medicine, Neurology, Kuopio (Finland); Vanninen, Ritva [Kuopio University Hospital, Department of Clinical Radiology, Kuopio (Finland); University of Eastern Finland, Institute of Clinical Medicine, Clinical Radiology, Kuopio (Finland)

2012-04-15

The purpose of this study is to establish the most suitable combination of functional magnetic resonance imaging (fMRI) language tasks for clinical use in determining language dominance and to define the variability in laterality index (LI) and activation power between different combinations of language tasks. Activation patterns of different fMRI analyses of five language tasks (word generation, responsive naming, letter task, sentence comprehension, and word pair) were defined for 20 healthy volunteers (16 right-handed). LIs and sums of T values were calculated for each task separately and for four combinations of tasks in predefined regions of interest. Variability in terms of activation power and lateralization was defined in each analysis. In addition, the visual assessment of lateralization of language functions based on the individual fMRI activation maps was conducted by an experienced neuroradiologist. A combination analysis of word generation, responsive naming, and sentence comprehension was the most suitable in terms of activation power, robustness to detect essential language areas, and scanning time. In general, combination analyses of the tasks provided higher overall activation levels than single tasks and reduced the number of outlier voxels disturbing the calculation of LI. A combination of auditory and visually presented tasks that activate different aspects of language functions with sufficient activation power may be a useful task battery for determining language dominance in patients. (orig.)

The effect of fMRI task combinations on determining the hemispheric dominance of language functions.

Science.gov (United States)

Niskanen, Eini; Könönen, Mervi; Villberg, Ville; Nissi, Mikko; Ranta-Aho, Perttu; Säisänen, Laura; Karjalainen, Pasi; Aikiä, Marja; Kälviäinen, Reetta; Mervaala, Esa; Vanninen, Ritva

2012-04-01

The purpose of this study is to establish the most suitable combination of functional magnetic resonance imaging (fMRI) language tasks for clinical use in determining language dominance and to define the variability in laterality index (LI) and activation power between different combinations of language tasks. Activation patterns of different fMRI analyses of five language tasks (word generation, responsive naming, letter task, sentence comprehension, and word pair) were defined for 20 healthy volunteers (16 right-handed). LIs and sums of T values were calculated for each task separately and for four combinations of tasks in predefined regions of interest. Variability in terms of activation power and lateralization was defined in each analysis. In addition, the visual assessment of lateralization of language functions based on the individual fMRI activation maps was conducted by an experienced neuroradiologist. A combination analysis of word generation, responsive naming, and sentence comprehension was the most suitable in terms of activation power, robustness to detect essential language areas, and scanning time. In general, combination analyses of the tasks provided higher overall activation levels than single tasks and reduced the number of outlier voxels disturbing the calculation of LI. A combination of auditory and visually presented tasks that activate different aspects of language functions with sufficient activation power may be a useful task battery for determining language dominance in patients.

Pharmaco fMRI: Determining the functional anatomy of the effects of medication.

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Wandschneider, Britta; Koepp, Matthias J

2016-01-01

Functional MRI studies have helped to elucidate underlying mechanisms in complex neurological and neuropsychiatric disorders. Disease processes often involve complex large-scale network interactions, extending beyond the presumed main disease focus. Given both the complexity of the clinical phenotype and the underlying dysfunctional brain circuits, so called pharmaco-fMRI (ph-MRI) studies probe pharmacological effects on functional neuro-anatomy, and can help to determine early treatment response, mechanisms of drug efficacy and side effects, and potentially advance CNS drug development. In this review, we discuss recent ph-MRI research in three major neuropsychiatric and neurological disorders and associated network alterations, namely selective serotonin and noradrenergic reuptake inhibitors in affective disorders and emotional processing circuits; antiepileptic drugs in epilepsy and cognitive networks; and stimulants in attention-deficit/hyperactivity disorder and networks of attention control. We conclude that ph-MRI studies show consistent and reproducible changes on disease relevant networks, and prove sensitive to early pharmacological effects on functional anatomy associated with disease. Further CNS drug research and development would benefit greatly from improved disease phenotyping, or biomarkers, using advanced imaging techniques.

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

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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.

Development of contaminant detection system based on ultra-low field SQUID-NMR/MRI

International Nuclear Information System (INIS)

Tsunaki, S; Yamamoto, M; Hatta, J; Hatsukade, Y; Tanaka, S

2014-01-01

We have developed an ultra-low field (ULF) NMR/MRI system using an HTS-rf-SQUID and evaluated performance of the system as a contaminant detection system for foods and drinks. In this work, we measured 1D MRIs from water samples with or without various contaminants, such as aluminum and glass balls using the system. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. We measured 2D MRIs from food samples with and without a hole. In the 2D MRIs, the hole position in the sample was well visualized. These results show that the feasibility of the system to detect and localize contaminants in foods and drinks.

Functional MRI in pre-surgical planning: Case study and cautionary notes

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Bruce S Spottiswoode

2012-09-01

Full Text Available Background. Since its inception almost 20 years ago, functional magnetic resonance imaging (fMRI has greatly advanced our knowledge of human brain function. Although the clinical applications of fMRI are still limited, there have recently been encouraging advances for its use in pre-operative functional cortical mapping to identify potentially eloquent areas prior to neurosurgery. Objectives. We explore the potential use of this emerging technique by presenting a neurosurgical case study, as performed at the Cape Universities Brain Imaging Centre (CUBIC, Tygerberg, Cape Town. We conclude with a brief summary of the potential pitfalls of this technique, as well as cautionary guidelines based on our experience. Methods and results. A 22-year-old male patient from Tygerberg Hospital underwent the successful resection of an anaplastic astrocytoma after fMRI presurgical planning at our facility. The subject was able to leave the ward unassisted. Conclusion. If consideration is given to the many limitations of this emerging technique, fMRI can be useful in aiding the neurosurgeon in pre-operative planning of his surgical approach.

Sensitivity of MRI in detecting alveolar infiltrates. Experimental studies

International Nuclear Information System (INIS)

Biederer, J.; Busse, I.; Grimm, J.; Reuter, M.; Heller, M.; Muhle, C.; Freitag, S.

2002-01-01

Purpose: An experimental study using porcine lung explants and a dedicated chest phantom to evaluate the signal intensity of artificial alveolar infiltrates with T 1 - and T 2 -weighted MRI sequences. Material and Methods: 10 porcine lung explants were intubated, transferred into the cavity of a MRI-compatible chest phantom and inflated by continuous evacuation of the artificial pleural space. All lungs were examined with MRI at 1.5 T before and after intra-tracheal instillation of either 100 or 200 ml gelatine-stabilised liquid to simulate alveolar infiltrates. MR-examination comprised gradient echo (2D- and 3D-GRE) and fast spin echo sequences (T 2 -TSE and T 2 -HASTE). The signal intensity of lung parenchyma was evaluated at representative cross sections using a standardised scheme. Control studies were acquired with helical CT. Results: The instilled liquid caused patchy confluent alveolar infiltrates resembling the findings in patients with pneumonia or ARDS. CT revealed typical ground-glass opacities. Before the application of the liquid, only T 2 -HASTE and T 2 -TSE displayed lung parenchyma signals with a signal/noise ratio of 3.62 and 1.39, respectively. After application of the liquid, both T 2 -weighted sequences showed clearly visible infiltrates with an increase in signal intensity of approx. 30% at 100 ml (p 2 -weighted sequences detects artificial alveolar infiltrates with high signal intensity and may be a highly sensitive tool to detect pneumonia in patients. (orig.) [de

Functional MRI studies of the neural mechanisms of human brain attentional networks

International Nuclear Information System (INIS)

Hao Jing; Li Kuncheng; Chen Qi; Wang Yan; Peng Xiaozhe; Zhou Xiaolin

2005-01-01

Objective: To identify the neural mechanisms of the anterior attention network (AAN) and posterior attention network (PAN) , investigate the possible interaction between them with event-related functional MRI(ER-fMRI). Methods: Eight right-handed healthy volunteers participated in the experiment designed with inhibition of return in visual orienting and Stroop color-word interference effect. The fMRI data were collected on Siemens 1.5 T Sonata MRI systems and analyzed by AFNI to generate the activation map. Results: The data sets from 6 of 8 subjects were used in the study. The functional localizations of the Stroop and IOR, which manifest the function of the AAN and PAN respectively, were consistent with previous imaging researches. On cued locations, left inferior parietal lobule (IPL), area MT/V5, right dorsolateral prefrontal cortex (DLPFC) and left anterior cingulated cortex (ACC) were significantly activated. On uncued locations, right superior parietal lobule (SPL) and bilateral area MT/V5 were significantly activated. Conclusion: The AAN exerts control over the PAN, while its function can be in turn modulated by the PAN. There are interaction between the AAN and PAN. In addition, it is also proved that ER-fMRI is a feasible method to revise preexisting cognitive model and theory. (authors)

Functional connectivity analysis of the brain network using resting-state fMRI

International Nuclear Information System (INIS)

Hayashi, Toshihiro

2011-01-01

Spatial patterns of spontaneous fluctuations in blood oxygenation level-dependent (BOLD) signals reflect the underlying neural architecture. The study of the brain network based on these self-organized patterns is termed resting-state functional MRI (fMRI). This review article aims at briefly reviewing a basic concept of this technology and discussing its implications for neuropsychological studies. First, the technical aspects of resting-state fMRI, including signal sources, physiological artifacts, image acquisition, and analytical methods such as seed-based correlation analysis and independent component analysis, are explained, followed by a discussion on the major resting-state networks, including the default mode network. In addition, the structure-function correlation studied using diffuse tensor imaging and resting-state fMRI is briefly discussed. Second, I have discussed the reservations and potential pitfalls of 2 major imaging methods: voxel-based lesion-symptom mapping and task fMRI. Problems encountered with voxel-based lesion-symptom mapping can be overcome by using resting-state fMRI and evaluating undamaged brain networks in patients. Regarding task fMRI in patients, I have also emphasized the importance of evaluating the baseline brain activity because the amplitude of activation in BOLD fMRI is hard to interpret as the same baseline cannot be assumed for both patient and normal groups. (author)

Assessment of pulmonary structure-function relationships in young children and adolescents with cystic fibrosis by multivolume proton-MRI and CT.

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Pennati, Francesca; Roach, David J; Clancy, John P; Brody, Alan S; Fleck, Robert J; Aliverti, Andrea; Woods, Jason C

2018-02-19

Lung disease is the most frequent cause of morbidity and mortality in patients with cystic fibrosis (CF), and there is a shortage of sensitive biomarkers able to regionally monitor disease progression and to assess early responses to therapy. To determine the feasibility of noncontrast-enhanced multivolume MRI, which assesses intensity changes between expiratory and inspiratory breath-hold images, to detect and quantify regional ventilation abnormalities in CF lung disease, with a focus on the structure-function relationship. Retrospective. Twenty-nine subjects, including healthy young children (n = 9, 7-37 months), healthy adolescents (n = 4, 14-22 years), young children with CF lung disease (n = 10, 7-47 months), and adolescents with CF lung disease (n = 6, 8-18 years) were studied. 3D spoiled gradient-recalled sequence at 1.5T. Subjects were scanned during breath-hold at functional residual capacity (FRC) and total lung capacity (TLC) through noncontrast-enhanced MRI and CT. Expiratory-inspiratory differences in MR signal-intensity (Δ 1 H-MRI) and CT-density (ΔHU) were computed to estimate regional ventilation. MR and CT images were also evaluated using a CF-specific scoring system. Quadratic regression, Spearman's correlation, one-way analysis of variance (ANOVA). Δ 1 H-MRI maps were sensitive to ventilation heterogeneity related to gravity dependence in healthy lung and to ventilation impairment in CF lung disease. A high correlation was found between MRI and CT ventilation maps (R 2  = 0.79, P < 0.001). Globally, Δ 1 H-MRI and ΔHU decrease with increasing morphological score (respectively, R 2  = 0.56, P < 0.001 and R 2  = 0.31, P < 0.001). Locally, Δ 1 H-MRI was higher in healthy regions (median 15%) compared to regions with bronchiectasis, air trapping, consolidation, and to segments fed by airways with bronchial wall thickening (P < 0.001). Multivolume noncontrast-enhanced MRI, as a nonionizing imaging

Value of FDG-PET vs MRI/CT in detection and staging of early uterine cervical cancer

International Nuclear Information System (INIS)

Kluge, P.; Kratzsch, A.; Horn, L.; Schmidt, F.; Einkel, J.; Sabri, O.

2003-01-01

This prospective study was performed to define the efficiency of FDG-PET in detecting primaries and in preoperatively assessing lymph node metastases of cervical cancer. Forty one patients with cervical cancer were investigated with PET (370 MBq F-18-FDG, Siemens ECAT EXACT HR+, visual evaluation) and MRI prior radical hysterectomy with pelvic, and additionally 12 cases paraortal, lymphadenectomies. Histopathological evaluation verified in all cases the evidence of cervical cancer except in one case, where the tumor was completely removed by conisation procedure. Sensitivity of PET and MRI were 95% and 85%, respectively. In 16/82 pelvic lymph node sites metastases were histologically detected (7 x micrometastases). Sensitivity, specificity, positive positive and negative predictive value were 50%, 85%, 44% and 88% for PET and 31%, 90%, 40% and 86% for MRI. Out of the 12 cases with dissection of paraortal lymph nodes, metastases were found histologically in 3 cases. PET detected 2/3 truly with no false positive result while CT detected 0/3 cases with no false positive findings. It is concluded that PET can detect cervical cancer with high accuracy. The accuracy of PET and MRI was similar for detection of pelvic metastases. Both methods have limited sensitivity due to the high incidence of micrometastases. PET was more accurate than CT in detection of paraortal metastases

Automated lesion detection on MRI scans using combined unsupervised and supervised methods

International Nuclear Information System (INIS)

Guo, Dazhou; Fridriksson, Julius; Fillmore, Paul; Rorden, Christopher; Yu, Hongkai; Zheng, Kang; Wang, Song

2015-01-01

Accurate and precise detection of brain lesions on MR images (MRI) is paramount for accurately relating lesion location to impaired behavior. In this paper, we present a novel method to automatically detect brain lesions from a T1-weighted 3D MRI. The proposed method combines the advantages of both unsupervised and supervised methods. First, unsupervised methods perform a unified segmentation normalization to warp images from the native space into a standard space and to generate probability maps for different tissue types, e.g., gray matter, white matter and fluid. This allows us to construct an initial lesion probability map by comparing the normalized MRI to healthy control subjects. Then, we perform non-rigid and reversible atlas-based registration to refine the probability maps of gray matter, white matter, external CSF, ventricle, and lesions. These probability maps are combined with the normalized MRI to construct three types of features, with which we use supervised methods to train three support vector machine (SVM) classifiers for a combined classifier. Finally, the combined classifier is used to accomplish lesion detection. We tested this method using T1-weighted MRIs from 60 in-house stroke patients. Using leave-one-out cross validation, the proposed method can achieve an average Dice coefficient of 73.1 % when compared to lesion maps hand-delineated by trained neurologists. Furthermore, we tested the proposed method on the T1-weighted MRIs in the MICCAI BRATS 2012 dataset. The proposed method can achieve an average Dice coefficient of 66.5 % in comparison to the expert annotated tumor maps provided in MICCAI BRATS 2012 dataset. In addition, on these two test datasets, the proposed method shows competitive performance to three state-of-the-art methods, including Stamatakis et al., Seghier et al., and Sanjuan et al. In this paper, we introduced a novel automated procedure for lesion detection from T1-weighted MRIs by combining both an unsupervised and a

Superparamagnetic iron oxides for MRI

International Nuclear Information System (INIS)

Weissleder, R.; Reimer, P.

1993-01-01

Pharmaceutical iron oxide preparations have been used as MRI contrast agents for a variety of purposes. These agents predominantly decrease T2 relaxation times and therefore cause a decrease in signal intensity of tissues that contain the agent. After intravenous administration, dextran-coated iron oxides typically accumulate in phagocytic cells in liver and spleen. Clinical trials have shown that iron oxide increases lesion/liver and lesion/spleen contrast, that more lesions can be depicted than on plain MRI or CT, and that the size threshold for lesion detection decreases. Decreased uptake of iron oxides in liver has been observed in hepatitis and cirrhosis, potentially allowing the assessment of organ function. More recently a variety of novel, target-specific monocrystalline iron oxides compounds have been used for receptor and immunospecific images. Future development of targeted MRI contrast agents is critical for organ- or tissue-specific quantitative and functional MRI. (orig.)

Superparamagnetic iron oxides for MRI

Energy Technology Data Exchange (ETDEWEB)

Weissleder, R [MGH-NMR Center, Dept. of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Reimer, P [MGH-NMR Center, Dept. of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); [Inst. fuer Klinische Radiologie, Zentrale Roentgendiagnostik, Westfaelische-Wilhelms-Univ., Muenster (Germany)

1993-06-01

Pharmaceutical iron oxide preparations have been used as MRI contrast agents for a variety of purposes. These agents predominantly decrease T2 relaxation times and therefore cause a decrease in signal intensity of tissues that contain the agent. After intravenous administration, dextran-coated iron oxides typically accumulate in phagocytic cells in liver and spleen. Clinical trials have shown that iron oxide increases lesion/liver and lesion/spleen contrast, that more lesions can be depicted than on plain MRI or CT, and that the size threshold for lesion detection decreases. Decreased uptake of iron oxides in liver has been observed in hepatitis and cirrhosis, potentially allowing the assessment of organ function. More recently a variety of novel, target-specific monocrystalline iron oxides compounds have been used for receptor and immunospecific images. Future development of targeted MRI contrast agents is critical for organ- or tissue-specific quantitative and functional MRI. (orig.)

Functional MRI in schizophrenia. Diagnostics and therapy monitoring of cognitive deficits of schizophrenic patients by functional MRI

International Nuclear Information System (INIS)

Furtner, J.; Prayer, D.; Sachs, G.

2010-01-01

Cognitive impairments are core psychopathological components of the symptomatic of schizophrenic patients. These dysfunctions are generally related to attention, executive functions and memory. This report provides information on the importance of using functional magnetic resonance imaging (fMRI) for the diagnostics and therapy monitoring of the different subtypes of cognitive dysfunctions. Furthermore, it describes the typical differences in the activation of individual brain regions between schizophrenic patients and healthy control persons. This information should be helpful in identifying the deficit profile of each patient and create an individual therapy plan. (orig.) [de

The usefulness of MRI for detection of the thymus gland in myasthenia gravis

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Hokezu, Youichi; Kaseda, Syun; Arimura, Kimiyoshi; Osame, Mitsuhiro; Baba, Kuniaki (Kagoshima Univ. (Japan). Faculty of Medicine); Ohkubo, Koichi; Hagiwara, Hiroshi

1989-08-01

Seven patients with myasthenia gravis (MG) were examined to find thymus or thymoma employing chest radiographs, computed tomography (CT), pneumomediastinography (PMG), computed tomography after pneumomediastinography (PMG-CT) and magnetic resonance imaging (MRI). X-ray CT examination could reveal thymus only in half out of 6 cases scanned. On the other hand, MRI confirmed thymus or thymoma in 6 out of 7 patients. PMG and PMG-CT confirmed thymus or thymoma clearly in all of the 4 cases studied. PMG and PMG-CT examinations revealed thymus or thymoma more clearly than MRI. MRI is, however, an examination causing no pain to the patients and also more superior to X-ray CT in distinguishing between a thymus and mediastinal fat or vascular structure. In addition, MRI could reveal even capsules in thymoma which were never revealed by X-ray CT. We concluded that MRI could be an alternative method to CT and PMG in detection of thymus or thymoma in MG. (author).

The usefulness of MRI for detection of the thymus gland in myasthenia gravis

International Nuclear Information System (INIS)

Hokezu, Youichi; Kaseda, Syun; Arimura, Kimiyoshi; Osame, Mitsuhiro; Baba, Kuniaki; Ohkubo, Koichi; Hagiwara, Hiroshi.

1989-01-01

Seven patients with myasthenia gravis (MG) were examined to find thymus or thymoma employing chest radiographs, computed tomography (CT), pneumomediastinography (PMG), computed tomography after pneumomediastinography (PMG-CT) and magnetic resonance imaging (MRI). X-ray CT examination could reveal thymus only in half out of 6 cases scanned. On the other hand, MRI confirmed thymus or thymoma in 6 out of 7 patients. PMG and PMG-CT confirmed thymus or thymoma clearly in all of the 4 cases studied. PMG and PMG-CT examinations revealed thymus or thymoma more clearly than MRI. MRI is, however, an examination causing no pain to the patients and also more superior to X-ray CT in distinguishing between a thymus and mediastinal fat or vascular structure. In addition, MRI could reveal even capsules in thymoma which were never revealed by X-ray CT. We concluded that MRI could be an alternative method to CT and PMG in detection of thymus or thymoma in MG. (author)

Unexpected Coexisting Myocardial Infarction Detected by Delayed Enhancement MRI

Directory of Open Access Journals (Sweden)

Edouard Gerbaud

2009-01-01

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

Pharmaco fMRI: Determining the functional anatomy of the effects of medication

Directory of Open Access Journals (Sweden)

Britta Wandschneider

2016-01-01

Full Text Available Functional MRI studies have helped to elucidate underlying mechanisms in complex neurological and neuropsychiatric disorders. Disease processes often involve complex large-scale network interactions, extending beyond the presumed main disease focus. Given both the complexity of the clinical phenotype and the underlying dysfunctional brain circuits, so called pharmaco-fMRI (ph-MRI studies probe pharmacological effects on functional neuro-anatomy, and can help to determine early treatment response, mechanisms of drug efficacy and side effects, and potentially advance CNS drug development. In this review, we discuss recent ph-MRI research in three major neuropsychiatric and neurological disorders and associated network alterations, namely selective serotonin and noradrenergic reuptake inhibitors in affective disorders and emotional processing circuits; antiepileptic drugs in epilepsy and cognitive networks; and stimulants in attention-deficit/hyperactivity disorder and networks of attention control. We conclude that ph-MRI studies show consistent and reproducible changes on disease relevant networks, and prove sensitive to early pharmacological effects on functional anatomy associated with disease. Further CNS drug research and development would benefit greatly from improved disease phenotyping, or biomarkers, using advanced imaging techniques.

BOLDSync: a MATLAB-based toolbox for synchronized stimulus presentation in functional MRI.

Science.gov (United States)

Joshi, Jitesh; Saharan, Sumiti; Mandal, Pravat K

2014-02-15

Precise and synchronized presentation of paradigm stimuli in functional magnetic resonance imaging (fMRI) is central to obtaining accurate information about brain regions involved in a specific task. In this manuscript, we present a new MATLAB-based toolbox, BOLDSync, for synchronized stimulus presentation in fMRI. BOLDSync provides a user friendly platform for design and presentation of visual, audio, as well as multimodal audio-visual (AV) stimuli in functional imaging experiments. We present simulation experiments that demonstrate the millisecond synchronization accuracy of BOLDSync, and also illustrate the functionalities of BOLDSync through application to an AV fMRI study. BOLDSync gains an advantage over other available proprietary and open-source toolboxes by offering a user friendly and accessible interface that affords both precision in stimulus presentation and versatility across various types of stimulus designs and system setups. BOLDSync is a reliable, efficient, and versatile solution for synchronized stimulus presentation in fMRI study. Copyright © 2013 Elsevier B.V. All rights reserved.

Association between MRI-defined osteoarthritis, pain, function and strength 3-10 years following knee joint injury in youth sport.

Science.gov (United States)

Whittaker, Jackie L; Toomey, Clodagh M; Woodhouse, Linda J; Jaremko, Jacob L; Nettel-Aguirre, Alberto; Emery, Carolyn A

2017-10-10

Youth and young adults who participate in sport have an increased risk of knee injury and subsequent osteoarthritis. Improved understanding of the relationship between structural and clinical outcomes postinjury could inform targeted osteoarthritis prevention interventions. This secondary analysis examines the association between MRI-defined osteoarthritis and self-reported and functional outcomes, 3-10 years following youth sport-related knee injury in comparison to healthy controls. Participants included a subsample (n=146) of the Alberta Youth Prevention of Early Osteoarthritis cohort: specifically, 73 individuals with 3-10 years history of sport-related intra-articular knee injury and 73 age-matched, sex-matched and sport-matched controls with completed MRI studies. Outcomes included: MRI-defined osteoarthritis, radiographic osteoarthritis, Knee Injury and Osteoarthritis Outcome Score, Intermittent and Constant Osteoarthritis Pain, knee extensor/flexor strength, triple-hop and Y-balance test. Descriptive statistics and univariate logistic regression were used to compare those with and without MRI-defined osteoarthritis. Associations between MRI-defined osteoarthritis and each outcome were assessed using multivariable linear regression considering the influence of injury history, sex, body mass index and time since injury. Participant median age was 23 years (range 15-27), and 63% were female. MRI-defined osteoarthritis varied by injury history, injury type and surgical history and was not isolated to participants with ACL and/or meniscal injuries. Those with a previous knee injury had 10-fold (95% CI 2.3 to 42.8) greater odds of MRI-defined osteoarthritis than uninjured participants. MRI-defined osteoarthritis was independently significantly associated with quality of life, but not symptoms, strength or function. MRI-detected structural changes 3-10 years following youth sport-related knee injury may not dictate clinical symptomatology, strength or function

Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

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Berko, Netanel S.; Levin, Terry L. [Montefiore Medical Center, Department of Radiology, Bronx, NY (United States); Hay, Arielle [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States); Miami Children' s Hospital, Department of Pediatrics, Miami, FL (United States); Sterba, Yonit; Wahezi, Dawn [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States)

2015-09-15

Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31

Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

International Nuclear Information System (INIS)

Berko, Netanel S.; Levin, Terry L.; Hay, Arielle; Sterba, Yonit; Wahezi, Dawn

2015-01-01

Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31

Comparative evaluation of chest radiography, low-field MRI, the Shwachman-Kulczycki score and pulmonary function tests in patients with cystic fibrosis

International Nuclear Information System (INIS)

Anjorin, Angela; Vogl, Thomas J.; Schmidt, Helga; Posselt, Hans-Georg; Smaczny, Christina; Ackermann, Hanns; Deimling, Michael; Abolmaali, Nasreddin

2008-01-01

The aim of this study was to investigate whether the parenchymal lung damage in patients suffering from cystic fibrosis (CF) can be equivalently quantified by the Chrispin-Norman (CN) scores determined with low-field magnetic resonance imaging (MRI) and conventional chest radiography (CXR). Both scores were correlated with pulmonary function tests (PFT) and the Shwachman-Kulczycki method (SKM). To evaluate the comparability of MRI and CXR for different states of the disease, all scores were applied to patients divided into three age groups. Seventy-three CF patients (mean SKM score: 62 ± 8) with a median age (range) of 14 years (7-32) were included. The mean CN scores determined with both imaging methods were comparable (CXR: 12.1 ± 4.7; MRI: 12.0 ± 4.5) and showed high correlation (P < 0.05, R = 0.97). Only weak correlations were found between imaging, PFT, and SKM. Both imaging modalities revealed significantly more severe disease expression with age, while PFT and SKM failed to detect early signs of disease. We conclude that imaging of the lung in CF patients is capable of detecting subtle and early parenchymal destruction before lung function or clinical scoring is affected. Furthermore, low-field MRI revealed high consistency with chest radiography and may be used for a thorough follow-up while avoiding radiation exposure. (orig.)

Detection of bone metastasis of prostate cancer. Comparison of whole-body MRI and bone scintigraphy

International Nuclear Information System (INIS)

Ketelsen, D.; Roethke, M.; Aschoff, P.; Lichy, M.P.; Claussen, C.D.; Schlemmer, H.P.; Merseburger, A.S.; Reimold, M.

2008-01-01

Purpose: prostate cancer continues to be the third leading cancer-related mortality of western men. Early diagnosis of bone metastasis is important for the therapy regime and for assessing the prognosis. The standard method is bone scintigraphy. Whole-body MRI proved to be more sensitive for early detection of skeletal metastasis. However, studies of homogenous tumor entities are not available. The aim of the study was to compare bone scintigraphy and whole-body MRI regarding the detection of bone metastasis of prostate cancer. Materials and methods: 14 patients with histologically confirmed prostate cancer and a bone scintigraphy as well as whole-body MRI within one month were included. The mean age was 68 years. Scintigraphy was performed using the planar whole-body technique (ventral and dorsal projections). Suspect areas were enlarged. Whole-body MRI was conducted using native T1w and STIR sequences in the coronary plane of the whole body, sagittal imaging of spine and breath-hold STIR and T1w-Flash-2D sequences of ribs and chest. Bone scintigraphy and whole-body MRI were evaluated retrospectively by experienced radiologists in a consensus reading on a lesion-based level. Results: whole-body MRI detected significantly more bone metastasis (p = 0.024). 96.4% of the demonstrated skeletal metastases in bone scintigraphy were founded in whole-body MRI while only 58.6% of the depicted metastases in MRI were able to be located in scintigraphy. There was no significant difference regarding bone metastasis greater than one centimeter (p = 0.082) in contrast to metastasis less than one centimeter (p = 0.035). Small osteoblastic metastases showed a considerably higher contrast in T1w sequences than in STIR imaging. Further advantages of whole-body MRI were additional information about extra-osseous tumor infiltration and their complications, for example stenosis of spinal canal or vertebral body fractures, found in 42.9% of patients. (orig.)

Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences.

Science.gov (United States)

Finkenstaedt, Tim; Del Grande, Filippo; Bolog, Nicolae; Ulrich, Nils; Tok, Sina; Kolokythas, Orpheus; Steurer, Johann; Andreisek, Gustav; Winklhofer, Sebastian

2018-02-01

 To assess the performance of fat-suppressed fluid-sensitive MRI sequences compared to T1-weighted (T1w) / T2w sequences for the detection of Modic 1 end-plate changes on lumbar spine MRI.  Sagittal T1w, T2w, and fat-suppressed fluid-sensitive MRI images of 100 consecutive patients (consequently 500 vertebral segments; 52 female, mean age 74 ± 7.4 years; 48 male, mean age 71 ± 6.3 years) were retrospectively evaluated. We recorded the presence (yes/no) and extension (i. e., Likert-scale of height, volume, and end-plate extension) of Modic I changes in T1w/T2w sequences and compared the results to fat-suppressed fluid-sensitive sequences (McNemar/Wilcoxon-signed-rank test).  Fat-suppressed fluid-sensitive sequences revealed significantly more Modic I changes compared to T1w/T2w sequences (156 vs. 93 segments, respectively; p definition of Modic I changes is not fully applicable anymore.. · Fat-suppressed fluid-sensitive MRI sequences revealed more/greater extent of Modic I changes.. · Finkenstaedt T, Del Grande F, Bolog N et al. Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences. Fortschr Röntgenstr 2018; 190: 152 - 160. © Georg Thieme Verlag KG Stuttgart · New York.

New procedures. Comprehensive staging of lung cancer by MRI

International Nuclear Information System (INIS)

Hintze, C.; Dinkel, J.; Biederer, J.; Heussel, C.P.; Puderbach, M.

2010-01-01

Lung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification are measurable with MRI. Pulmonary nodules can be detected at the clinically relevant size of 4-5 mm in diameter. The extent of mediastinal, hilar and supraclavicular lymph node affection can be assessed at the same time. The predominant metastatic spread to the adrenal glands and spine can be detected in coronal orientation during dedicated MRI of the lungs. Search focused whole body MRI completes the staging. Various additional MR imaging techniques provide further functional and clinically relevant information during a single examination. In the oncological context the most important techniques are imaging of perfusion and tumor motion. Functional MRI of the lungs complements the pure staging and improves surgical approaches and radiotherapy planning. (orig.) [de

Use of contrast agents for liver MRI

International Nuclear Information System (INIS)

Ward, Janice

2007-01-01

Contrast-enhanced MRI is recognised as one of the most accurate imaging methods for investigating diseases of the liver. Uniquely several different types of contrast agents are available for liver MRI. They can be divided into non-specific extracellular fluid space (ECF), hepatocyte specific and reticulo-endothelial system (RES) specific agents. They are used to improve the detection of focal liver lesions by increasing normal-abnormal tissue contrast and to assist in lesion characterisation by demonstrating tissue perfusion and cellular function. ECF-gadolinium (Gd) chelates have been widely used in abdominal MRI for many years. They provide valuable information regarding the vascularisation and perfusion characteristics of lesions and assist in lesion detection, particularly of hypervascular lesions. The hepatocyte and RES-specific agents further improve lesion detection, provide important functional information and allow the distinction between hepatocellular and non-hepatocellular tumours. This article describes the different MR contrast agents and discusses their current status for diagnosing focal liver lesions. The importance of optimised technique and appropriate selection of contrast agent is emphasised

[MRI methods for pulmonary ventilation and perfusion imaging].

Science.gov (United States)

Sommer, G; Bauman, G

2016-02-01

Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O2-enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies.

MRI methods for pulmonary ventilation and perfusion imaging

International Nuclear Information System (INIS)

Sommer, G.; Bauman, G.

2016-01-01

Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O 2 -enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies. (orig.) [de

Adrenal phaeochromocytoma: correlation of MRI appearances with histology and function

International Nuclear Information System (INIS)

Jacques, Audrey E.T.; Sahdev, Anju; Sandrasagara, Madrika; Rockall, Andrea G.; Reznek, Rodney H.; Goldstein, Rick; Chew, Shern; Berney, Daniel

2008-01-01

The purpose of this study was to describe the range of appearances of adrenal phaeochromocytomas on T2-weighted MRI, correlate appearances with histopathology, and quantify the incidence of the previously described hyperintense appearance. The appearance and MR characteristics of 44 phaeochromocytomas were reviewed retrospectively. T2-weighted appearances were grouped: (1) 'classical', homogeneous, high signal intensity, isointense to CSF; (2) homogeneous, isointense or minimally hyperintense to spleen, hypointense to CSF; (3) heterogeneous, marbled appearance; (4) heterogeneous, multiple high signal intensity pockets. All 44 adrenal phaeochromocytomas were well circumscribed, 1.2-15 cm in maximum diameter, with no visual or quantitative signal loss on chemical shift imaging. On T2-weighted MRI 5/44 (11%) had group 1 appearance; 15/44 (34%) group 2, 7/44 (16%) group 3; and 17/44 (39%) group 4. Homogeneous group 1 and 2 lesions were smaller (mean 4.5 cm) than heterogeneous group 3 and 4 lesions (mean 6.3 cm). Increasing MRI heterogeneity correlated pathologically with increasing amounts of haemorrhage, necrosis and fibrosis. No MRI features were predictive of malignancy. Non-functioning phaeochromocytomas were larger than functioning lesions. No size difference was seen between syndrome and sporadic lesions. In this large series we report a wide range of appearances of adrenal phaeochromocytomas on T2-weighted MRI. The previously described classical hyperintense phaeochromocytoma is relatively uncommon. (orig.)

Multiparametric MRI of the prostate. Method for early detection of prostate cancer?

International Nuclear Information System (INIS)

Schlemmer, Heinz-Peter

2010-01-01

Current approaches for the early detection of prostate cancer are controversially discussed because the disease is characterized by a high incidence rate with a relatively low morbidity rate, availability of only limited prognostic markers, and continued therapy-related morbidity. Conventional morphological MRI does not play a role in early detection since small tumor foci cannot be delineated. However, if there is clinical suspicion for prostate cancer, multiparametric MRI is currently the most accurate method for detecting and characterizing suspicious lesions in the prostate. The potential to identify the so-called 'index lesion', i.e., the tumor area that is most aggressive and determines treatment, is particularly important. This information can increase the accuracy of prostate biopsy and serve as a biomarker for follow-up during active surveillance. The method may considerably contribute to the urgently required separation of clinically significant from clinically insignificant prostate cancers. (orig.)

MRI with DWI for the Detection of Posttreatment Head and Neck Squamous Cell Carcinoma: Why Morphologic MRI Criteria Matter.

Science.gov (United States)

Ailianou, A; Mundada, P; De Perrot, T; Pusztaszieri, M; Poletti, P-A; Becker, M

2018-04-01

Although diffusion-weighted imaging combined with morphologic MRI (DWIMRI) is used to detect posttreatment recurrent and second primary head and neck squamous cell carcinoma, the diagnostic criteria used so far have not been clarified. We hypothesized that precise MRI criteria based on signal intensity patterns on T2 and contrast-enhanced T1 complement DWI and therefore improve the diagnostic performance of DWIMRI. We analyzed 1.5T MRI examinations of 100 consecutive patients treated with radiation therapy with or without additional surgery for head and neck squamous cell carcinoma. MRI examinations included morphologic sequences and DWI ( b =0 and b =1000 s/mm 2 ). Histology and follow-up served as the standard of reference. Two experienced readers, blinded to clinical/histologic/follow-up data, evaluated images according to clearly defined criteria for the diagnosis of recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment, post-radiation therapy inflammatory edema, and late fibrosis. DWI analysis included qualitative (visual) and quantitative evaluation with an ADC threshold. Recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment was present in 36 patients, whereas 64 patients had post-radiation therapy lesions only. The Cohen κ for differentiating tumor from post-radiation therapy lesions with MRI and qualitative DWIMRI was 0.822 and 0.881, respectively. Mean ADCmean in recurrent head and neck squamous cell carcinoma/second primary head and neck squamous cell carcinoma occurring after treatment (1.097 ± 0.295 × 10 -3 mm 2 /s) was significantly lower ( P .05). Although ADCs were similar in tumors and late fibrosis, morphologic MRI criteria facilitated distinction between the 2 conditions. The sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios (95% CI) of

Working memory capacity and the functional connectome - insights from resting-state fMRI and voxelwise centrality mapping.

Science.gov (United States)

Markett, Sebastian; Reuter, Martin; Heeren, Behrend; Lachmann, Bernd; Weber, Bernd; Montag, Christian

2018-02-01

The functional connectome represents a comprehensive network map of functional connectivity throughout the human brain. To date, the relationship between the organization of functional connectivity and cognitive performance measures is still poorly understood. In the present study we use resting-state functional magnetic resonance imaging (fMRI) data to explore the link between the functional connectome and working memory capacity in an individual differences design. Working memory capacity, which refers to the maximum amount of context information that an individual can retain in the absence of external stimulation, was assessed outside the MRI scanner and estimated based on behavioral data from a change detection task. Resting-state time series were analyzed by means of voxelwise degree and eigenvector centrality mapping, which are data-driven network analytic approaches for the characterization of functional connectivity. We found working memory capacity to be inversely correlated with both centrality in the right intraparietal sulcus. Exploratory analyses revealed that this relationship was putatively driven by an increase in negative connectivity strength of the structure. This resting-state connectivity finding fits previous task based activation studies that have shown that this area responds to manipulations of working memory load.

Mapping brain activity in gradient-echo functional MRI using principal component analysis

Science.gov (United States)

Khosla, Deepak; Singh, Manbir; Don, Manuel

1997-05-01

The detection of sites of brain activation in functional MRI has been a topic of immense research interest and many technique shave been proposed to this end. Recently, principal component analysis (PCA) has been applied to extract the activated regions and their time course of activation. This method is based on the assumption that the activation is orthogonal to other signal variations such as brain motion, physiological oscillations and other uncorrelated noises. A distinct advantage of this method is that it does not require any knowledge of the time course of the true stimulus paradigm. This technique is well suited to EPI image sequences where the sampling rate is high enough to capture the effects of physiological oscillations. In this work, we propose and apply tow methods that are based on PCA to conventional gradient-echo images and investigate their usefulness as tools to extract reliable information on brain activation. The first method is a conventional technique where a single image sequence with alternating on and off stages is subject to a principal component analysis. The second method is a PCA-based approach called the common spatial factor analysis technique (CSF). As the name suggests, this method relies on common spatial factors between the above fMRI image sequence and a background fMRI. We have applied these methods to identify active brain ares during visual stimulation and motor tasks. The results from these methods are compared to those obtained by using the standard cross-correlation technique. We found good agreement in the areas identified as active across all three techniques. The results suggest that PCA and CSF methods have good potential in detecting the true stimulus correlated changes in the presence of other interfering signals.

Serial cranial ultrasonography or early MRI for detecting preterm brain injury?

NARCIS (Netherlands)

Plaisier, Annemarie; Raets, Marlou M A; Ecury-Goossen, Ginette M; Govaert, Paul; Feijen-Roon, Monique; Reiss, Irwin K M; Smit, Liesbeth S; Lequin, Maarten H; Dudink, Jeroen

OBJECTIVE: To investigate detection ability and feasibility of serial cranial ultrasonography (CUS) and early MRI in preterm brain injury. DESIGN: Prospective cohort study. SETTING: Level III neonatal intensive care unit. PATIENTS: 307 infants, born below 29 weeks of gestation. METHODS: Serial CUS

Structural and functional abnormalities of default mode network in minimal hepatic encephalopathy: a study combining DTI and fMRI.

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Rongfeng Qi

Full Text Available BACKGROUND AND PURPOSE: Live failure can cause brain edema and aberrant brain function in cirrhotic patients. In particular, decreased functional connectivity within the brain default-mode network (DMN has been recently reported in overt hepatic encephalopathy (HE patients. However, so far, little is known about the connectivity among the DMN in the minimal HE (MHE, the mildest form of HE. Here, we combined diffusion tensor imaging (DTI and resting-state functional MRI (rs-fMRI to test our hypothesis that both structural and functional connectivity within the DMN were disturbed in MHE. MATERIALS AND METHODS: Twenty MHE patients and 20 healthy controls participated in the study. We explored the changes of structural (path length, tracts count, fractional anisotropy [FA] and mean diffusivity [MD] derived from DTI tractography and functional (temporal correlation coefficient derived from rs-fMRI connectivity of the DMN in MHE patients. Pearson correlation analysis was performed between the structural/functional indices and venous blood ammonia levels/neuropsychological tests scores of patients. All thresholds were set at P<0.05, Bonferroni corrected. RESULTS: Compared to the healthy controls, MHE patients showed both decreased FA and increased MD in the tract connecting the posterior cingulate cortex/precuneus (PCC/PCUN to left parahippocampal gyrus (PHG, and decreased functional connectivity between the PCC/PCUN and left PHG, and medial prefrontal cortex (MPFC. MD values of the tract connecting PCC/PCUN to the left PHG positively correlated to the ammonia levels, the temporal correlation coefficients between the PCC/PCUN and the MPFC showed positive correlation to the digital symbol tests scores of patients. CONCLUSION: MHE patients have both disturbed structural and functional connectivity within the DMN. The decreased functional connectivity was also detected between some regions without abnormal structural connectivity, suggesting that the

Quantitation of global and regional left ventricular function by MRI

NARCIS (Netherlands)

van der Geest, RJ; Reiber, JHC; Reiber, JHC; VanDerWall, EE

1998-01-01

Magnetic resonance imaging (MRI) provides several imaging strategies for assessing left ventricular function. As a three-dimensional imaging technique, all measurements can be performed without relying on geometrical assumptions. Global and regional function parameters can be derived from

Acquisition and analysis strategies in functional MRI at high fields

International Nuclear Information System (INIS)

Windischberger, C.

2001-08-01

Functional magnetic resonance imaging represents a non-invasive technique to examine neuronal activity in the brain. It applies radio waves to excite nuclear spins, using the emitted signal during relaxation for image generation. Signal modulations from local blood flow and oxygenation level changes caused by neuronal activity are the basis for calculating functional brain maps with high spatial resolution. The present work discusses concepts for improving the spatial and temporal resolution, as well as sophisticated analysis approaches. Besides an exhaustive description of image reconstruction algorithms, computational simulations on echo-shifting in echo-planar imaging are presented and effects on spatial resolution are quantified. The results demonstrate that echo-shifting causes only minimal resolution losses for high signal-to-noise data, but leads to severe resolution degradation (up to 30 %) in images with low signal-to-noise ratios. After an overview of the mechanisms that cause fMRI signal changes subsequent to neuronal activity, explorative analysis algorithms like Fuzzy Cluster Analysis, as well as parametric approaches are described and discussed. In the context of fMRI artifacts, effects of respiratory motion are examined. For the first time, well-defined breathing patterns are used to quantify the influences on fMRI signal intensity. Also, the variability of fMRI activation in a mental rotation paradigm are investigated, using single-trial analysis. Such, intra-subject activation consistency was determined successfully. Finally, in a second study on mental rotation explorative data analysis was applied to retrieve neuro-functional hypotheses. (author)

Automatic cardiac cycle determination directly from EEG-fMRI data by multi-scale peak detection method.

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Wong, Chung-Ki; Luo, Qingfei; Zotev, Vadim; Phillips, Raquel; Chan, Kam Wai Clifford; Bodurka, Jerzy

2018-03-31

In simultaneous EEG-fMRI, identification of the period of cardioballistic artifact (BCG) in EEG is required for the artifact removal. Recording the electrocardiogram (ECG) waveform during fMRI is difficult, often causing inaccurate period detection. Since the waveform of the BCG extracted by independent component analysis (ICA) is relatively invariable compared to the ECG waveform, we propose a multiple-scale peak-detection algorithm to determine the BCG cycle directly from the EEG data. The algorithm first extracts the high contrast BCG component from the EEG data by ICA. The BCG cycle is then estimated by band-pass filtering the component around the fundamental frequency identified from its energy spectral density, and the peak of BCG artifact occurrence is selected from each of the estimated cycle. The algorithm is shown to achieve a high accuracy on a large EEG-fMRI dataset. It is also adaptive to various heart rates without the needs of adjusting the threshold parameters. The cycle detection remains accurate with the scan duration reduced to half a minute. Additionally, the algorithm gives a figure of merit to evaluate the reliability of the detection accuracy. The algorithm is shown to give a higher detection accuracy than the commonly used cycle detection algorithm fmrib_qrsdetect implemented in EEGLAB. The achieved high cycle detection accuracy of our algorithm without using the ECG waveforms makes possible to create and automate pipelines for processing large EEG-fMRI datasets, and virtually eliminates the need for ECG recordings for BCG artifact removal. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Diffusion-weighted imaging as part of hybrid PET/MRI protocols for whole-body cancer staging: Does it benefit lesion detection?

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Buchbender, Christian, E-mail: christian.buchbender@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Hartung-Knemeyer, Verena, E-mail: verena.hartung@uk-essen.de [Univ Duisburg-Essen, Medical Faculty, Department of Nuclear Medicine, Hufelandstr. 55, D-45147 Essen (Germany); Beiderwellen, Karsten, E-mail: karsten.beiderwellen@uk-essen.de [Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Hufelandstr. 55, D-45147 Essen (Germany); Heusch, Philipp, E-mail: philipp.heusch@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Kühl, Hilmar, E-mail: hilmar.kuehl@uni-due.de [Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Hufelandstr. 55, D-45147 Essen (Germany); Lauenstein, Thomas C., E-mail: thomas.lauenstein@uk-essen.de [Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Hufelandstr. 55, D-45147 Essen (Germany); Forsting, Michael, E-mail: michael.forsting@uk-essen.de [Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Hufelandstr. 55, D-45147 Essen (Germany); Antoch, Gerald, E-mail: antoch@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Heusner, Till A., E-mail: heusner@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany)

2013-05-15

Purpose: Positron emission tomography/magnetic resonance imaging (PET/MRI) requires efficient scan protocols for whole-body cancer staging. The aim of this study was to evaluate if the application of diffusion-weighted MR imaging (DWI) results in a diagnostic benefit for lesion detection in oncologic patients if added to a whole-body [18F]-fluorodesoxyglucose ([18F]-FDG) PET/MRI protocol. Methods: 25 consecutive oncologic patients (16 men, 9 women; age 57 ± 12 years) prospectively underwent whole-body [18F]-FDG-PET/MRI including DWI on a hybrid PET/MRI scanner. A team of two readers assessed [18F]-FDG PET/MRI without DWI for primary tumors and metastases. In a second session, now considering DWI, readers reassessed [18F]-FDG PET/MRI accordingly. Additionally, the lesion-to-background contrast on [18F]-FDG PET and DWI was rated qualitatively (0, invisible; 1, low; 2, intermediate; 3, high). Wilcoxon's signed-rank test was performed to test for differences in the lesion-to-background contrast. Results: 49 lesions were detected in 16 patients (5 primaries, 44 metastases). All 49 lesions were concordantly detected by [18F]-FDG PET/MRI alone and [18F]-FDG PET/MRI with DWI. The lesion-to-background contrast on DWI compared to [18F]-FDG PET was rated lower in 22 (44.9%) of 49 detected lesions resulting in a significantly higher lesion-to-background contrast on [18F]-FDG PET compared to DWI (P = 0.001). Conclusions: DWI as part of whole-body [18F]-FDG PET/MRI does not benefit lesion detection. Given the necessity to optimize imaging protocols with regard to patient comfort and efficacy, DWI has to be questioned as a standard tool for whole-body staging in oncologic PET/MRI.

High frame rate retrospectively triggered Cine MRI for assessment of murine diastolic function.

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Coolen, Bram F; Abdurrachim, Desiree; Motaal, Abdallah G; Nicolay, Klaas; Prompers, Jeanine J; Strijkers, Gustav J

2013-03-01

To assess left ventricular (LV) diastolic function in mice with Cine MRI, a high frame rate (>60 frames per cardiac cycle) is required. For conventional electrocardiography-triggered Cine MRI, the frame rate is inversely proportional to the pulse repetition time (TR). However, TR cannot be lowered at will to increase the frame rate because of gradient hardware, spatial resolution, and signal-to-noise limitations. To overcome these limitations associated with electrocardiography-triggered Cine MRI, in this paper, we introduce a retrospectively triggered Cine MRI protocol capable of producing high-resolution high frame rate Cine MRI of the mouse heart for addressing left ventricular diastolic function. Simulations were performed to investigate the influence of MRI sequence parameters and the k-space filling trajectory in relation to the desired number of frames per cardiac cycle. An optimized protocol was applied in vivo and compared with electrocardiography-triggered Cine for which a high-frame rate could only be achieved by several interleaved acquisitions. Retrospective high frame rate Cine MRI proved superior to the interleaved electrocardiography-triggered protocols. High spatial-resolution Cine movies with frames rates up to 80 frames per cardiac cycle were obtained in 25 min. Analysis of left ventricular filling rate curves allowed accurate determination of early and late filling rates and revealed subtle impairments in left ventricular diastolic function of diabetic mice in comparison with nondiabetic mice. Copyright © 2012 Wiley Periodicals, Inc.

Comparison of post-surgical MRI presentation of the pituitary gland and its hormonal function.

Science.gov (United States)

Bladowska, Joanna; Sokolska, Violetta; Sozański, Tomasz; Bednarek-Tupikowska, Grażyna; Sąsiadek, Marek

2010-01-01

Post-surgical evaluation of the pituitary gland in MRI is difficult because of a change of anatomical conditions. It depends also on numerous other factors, including: size and expansion of a tumour before surgery, type of surgical access, quality and volume of filling material used and time of its resorption.The aim of the study was to compare MR image of the pituitary gland after surgery with clinical findings and to establish a correlation between MRI presentation of spared pituitary and its hormonal function. 124 patients after resection of pituitary adenomas - 409 MRI results in total - were studied. With a 1.5-T unit, T1-weighted sagittal and coronal, enhanced and unenhanced images were obtained. The pituitary gland seemed to be normal in MRI in 11 patients, 8 of them had completely regular pituitary function but in 3 of them we noticed a partial hypopituitarism. In 99 patients only a part of the pituitary gland was recognised, 53 of them had hypopituitarism but 46 of them were endocrinologically healthy. 14 patients seemed to have no persistent pituitary gland in MRI, in comparison to hormonal studies: there was panhypopituitarism in 6 and hypopituitarism in 8 cases. MRI presentation of post - surgical pituitary gland doesn't necessarily correlate with its hormonal function - there was a significant statistical difference. Some patients with partial pituitary seems normal hormonal function. In some cases the pituitary seem normal in MRI but these patients have hormonal disorders and need substitution therapy.

Altered brain functions in HIV positive patients free of HIV- associated neurocognitive disorders: A MRI study during unilateral hand movements

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Jing Zhao

2015-03-01

Full Text Available This paper aimed to investigate the brain activity of human immunodeficiency virus (HIV positive patients with normal cognition during unilateral hand movement and whether highly active antiretroviral therapy (HAART could affect the brain function. Functional magnetic resonance imaging (fMRI was performed for 60 HIV positive (HIV+ subjects and −42 healthy age-matched right-handed control subjects. Each subject was evaluated by the neuropsychological test and examined with fMRI during left and right hand movement tasks. HIV+ subjects showed greater activation in anterior cingulum, precuneus, occipital lobes, ipsilateral postcentral gyrus and contralateral cerebellum compared with control group during right hand movement task. However, during left hand movement no statistically significant difference was detected between these two groups. HAART medication for HIV+ subjects lowered the increased activity to normal level. Meanwhile patients receiving the regimen of zidovudine, lamivudine and efavirenz showed lower activity at bilateral caudate and ipsilateral inferior frontal gyrus in comparison with subjects receiving other HAART regimens. Therefore, HIV+ subjects demonstrated brain asymmetry in motor cortex, with increased activity present during right hand movement but absent during left hand movement. HAART proves effective in HIV+ subjects even with normal cognition and the specific regimen of HAART could prevent cerebral abnormal functions. Meanwhile, this study validates that during motor tasks, fMRI can detect the brain signal changes prior to the occurrences of other HIV- associated dysfunctions.

Functional MRI in Patients with Intracranial Lesions near Language Areas.

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Hakyemez, B; Erdogan, C; Yildirim, N; Bora, I; Bekar, A; Parlak, M

2006-06-30

We aimed to depict Broca's area and Wernicke's area by word generation and sentence formation paradigms in patients with various intracranial lesions adjacent to language areas using functional MRI technique and to evaluate the ability of functional MRI to lateralize the hemispheric dominance for language. Twenty-three right-handed patients were included in this study. Lesions were classified as low-grade glioma (n=8), high-grade glioma (n=9), metastasis (n=1), meningioma (n=1), arteriovenous malformation (n=2) and mesial temporal sclerosis (n=2). We performed blood-oxygenated-level-dependant functional MRI using a 1.5-T unit. Word generation and sentence formation tasks were used to activate language areas. Language areas were defined as Brodmann 44, 45 (Broca's area) and Brodmann 22 area (Wernicke's area). Laterality index was used to show the dominant hemisphere. Two poorly cooperative patients showed no activation and were excluded from the study. Broca's area was localized in 21 patients (100 %). Wernicke's area, on the other hand, could only be localized in eight of the 21 patients (38 %).The left hemisphere was dominant in 86% of patients while atypical language lateralization (right or bilateral) was demonstrated in 14% of the patients. Bilateral activation areas were shown in 10% of those patients while right cerebral hemisphere was dominant in 4% of the patients. Word generation and sentence formation tasks are especially helpful in localizing Broca's area. Wernicke's area could also be demonstrated in some of the cases. Functional MRI can be used as an important and useful means of demonstrating language areas in patients with lesions adjacent to those areas and depicting the hemispheric dominance.

Comparative studies of brain activation with MEG and functional MRI

International Nuclear Information System (INIS)

George, J.S.; Aine, C.J.; Sanders, J.A.; Lewine, J.D.; Caprihan, A.

1993-01-01

The past two years have witnessed the emergence of MRI as a functional imaging methodology. Initial demonstrations involved the injection of a paramagnetic contrast agent and required ultrafast echo planar imaging capability to adequately resolve the passage of the injected bolus. By measuring the local reduction in image intensity due to magnetic susceptibility, it was possible to calculate blood volume, which changes as a function of neural activation. Later developments have exploited endogenous contrast mechanisms to monitor changes in blood volume or in venous blood oxygen content. Recently, we and others have demonstrated that it is possible to make such measurements in a clinical imager, suggesting that the large installed base of such machines might be utilized for functional imaging. Although it is likely that functional MRI (fMRI) will subsume some of the clinical and basic neuroscience applications now touted for MEG, it is also clear that these techniques offer different largely complementary, capabilities. At the very least, it is useful to compare and cross-validate the activation maps produced by these techniques. Such studies will be valuable as a check on results of neuromagnetic distributed current reconstructions and will allow better characterization of the relationship between neurophysiological activation and associated hemodynamic changes. A more exciting prospect is the development of analyses that combine information from the two modalities to produce a better description of underlying neural activity than is possible with either technique in isolation. In this paper we describe some results from initial comparative studies and outline several techniques that can be used to treat MEG and fMRI data within a unified computational framework

Breast MRI, digital mammography and breast tomosynthesis: comparison of three methods for early detection of breast cancer.

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Roganovic, Dragana; Djilas, Dragana; Vujnovic, Sasa; Pavic, Dag; Stojanov, Dragan

2015-11-16

Breast cancer is the most common malignancy in women and early detection is important for its successful treatment. The aim of this study was to investigate the sensitivity and specificity of three methods for early detection of breast cancer: breast magnetic resonance imaging (MRI), digital mammography, and breast tomosynthesis in comparison to histopathology, as well as to investigate the intraindividual variability between these modalities. We included 57 breast lesions, each detected by three diagnostic modalities: digital mammography, breast MRI, and breast tomosynthesis, and subsequently confirmed by histopathology. Breast Imaging-Reporting and Data System (BI-RADS) was used for characterizing the lesions. One experienced radiologist interpreted all three diagnostic modalities. Twenty-nine of the breast lesions were malignant while 28 were benign. The sensitivity for digital mammography, breast MRI, and breast tomosynthesis, was 72.4%, 93.1%, and 100%, respectively; while the specificity was 46.4%, 60.7%, and 75%, respectively. Receiver operating characteristics (ROC) curve analysis showed an overall diagnostic advantage of breast tomosynthesis over both breast MRI and digital mammography. The difference in performance between breast tomosynthesis and digital mammography was significant (p tomosynthesis and breast MRI was not significant (p=0.20).

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

International Nuclear Information System (INIS)

Itou, Naoki; Kotake, Fumio; Saitou, Kazuhiro; Abe, Kimihiko

2000-01-01

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

Predictive values of BI-RADS® magnetic resonance imaging (MRI) in the detection of breast ductal carcinoma in situ (DCIS)

International Nuclear Information System (INIS)

Badan, Gustavo Machado; Piato, Sebastião; Roveda, Décio; Faria Castro Fleury, Eduardo de

2016-01-01

Purpose: The purpose of this study was to evaluate BI-RADS indicators in the detection of DCIS by MRI. Materials and methods: Prospective observational study that started in 2014 and lasted 24 months. A total of 110 consecutive patients were evaluated, who presented with suspicious or highly suspicious microcalcifications on screening mammography (BI-RADS categories 4 and 5) and underwent stereotactic-guided breast biopsy, having had an MRI scan performed prior to biopsy. Results: Altogether, 38 cases were characterized as positive for malignancy, of which 25 were DCIS and 13 were invasive ductal carcinoma cases. MRI had a sensitivity of 96%; specificity of 75.67%; positive predictive value (PPV) for DCIS detection of 57.14%; negative predictive value (NPV) in the detection of DCIS of 98.24%; and an accuracy of 80.80%. Conclusion: BI-RADS as a tool for the detection of DCIS by MRI is a powerful instrument whose sensitivity was higher when compared to that observed for mammography in the literature. Likewise, the PPV obtained by MRI was higher than that observed in the present study for mammography, and the high NPV obtained on MRI scans can provide early evidence to discourage breast biopsy in selected cases.

Functional MRI of the visual cortex and visual testing in patients with previous optic neuritis

DEFF Research Database (Denmark)

Langkilde, Annika Reynberg; Frederiksen, J.L.; Rostrup, Egill

2002-01-01

of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed...... a reduced blood oxygenation level dependent (BOLD) signal increase and a greater asymmetry in the visual cortex, compared with controls. The volume of visual cortical activation was significantly correlated to the result of the contrast sensitivity test. The BOLD signal increase correlated significantly......The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size...

Seven tesla MRI improves detection of focal cortical dysplasia in patients with refractory focal epilepsy

NARCIS (Netherlands)

Veersema, Tim J; Ferrier, Cyrille H; van Eijsden, Pieter; Gosselaar, Peter H; Aronica, Eleonora; Visser, Fredy; Zwanenburg, Jaco M; de Kort, Gerard A P; Hendrikse, Jeroen; Luijten, Peter R; Braun, Kees P J

Objective: The aim of this study is to determine whether the use of 7 tesla (T) MRI in clinical practice leads to higher detection rates of focal cortical dysplasias in possible candidates for epilepsy surgery. Methods: In our center patients are referred for 7 T MRI if lesional focal epilepsy is

A Tumor-Targeted Nanodelivery System to Improve Early MRI Detection of Cancer

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Kathleen F. Pirollo

2006-01-01

Full Text Available The development of improvements in magnetic resonance imaging (MRI that would enhance sensitivity, leading to earlier detection of cancer and visualization of metastatic disease, is an area of intense exploration. We have devised a tumor-targeting, liposomal nanodelivery platform for use in gene medicine. This systemically administered nanocomplex has been shown to specifically and efficiently deliver both genes and oligonucleotides to primary and metastatic tumor cells, resulting in significant tumor growth inhibition and even tumor regression. Here we examine the effect on MRI of incorporating conventional MRI contrast agent Magnevist® into our anti-transferrin receptor single-chain antibody (TfRscFv liposomal complex. Both in vitro and in an in vivo orthotopic mouse model of pancreatic cancer, we show increased resolution and image intensity with the complexed Magnevist®. Using advanced microscopy techniques (scanning electron microscopy and scanning probe microscopy, we also established that the Magnevist® is in fact encapsulated by the liposome in the complex and that the complex still retains its nanodimensional size. These results demonstrate that this TfRscFv-liposome-Magnevist® nanocomplex has the potential to become a useful tool in early cancer detection.

Upper Limb Evaluation in Duchenne Muscular Dystrophy: Fat-Water Quantification by MRI, Muscle Force and Function Define Endpoints for Clinical Trials.

Science.gov (United States)

Ricotti, Valeria; Evans, Matthew R B; Sinclair, Christopher D J; Butler, Jordan W; Ridout, Deborah A; Hogrel, Jean-Yves; Emira, Ahmed; Morrow, Jasper M; Reilly, Mary M; Hanna, Michael G; Janiczek, Robert L; Matthews, Paul M; Yousry, Tarek A; Muntoni, Francesco; Thornton, John S

2016-01-01

A number of promising experimental therapies for Duchenne muscular dystrophy (DMD) are emerging. Clinical trials currently rely on invasive biopsies or motivation-dependent functional tests to assess outcome. Quantitative muscle magnetic resonance imaging (MRI) could offer a valuable alternative and permit inclusion of non-ambulant DMD subjects. The aims of our study were to explore the responsiveness of upper-limb MRI muscle-fat measurement as a non-invasive objective endpoint for clinical trials in non-ambulant DMD, and to investigate the relationship of these MRI measures to those of muscle force and function. 15 non-ambulant DMD boys (mean age 13.3 y) and 10 age-gender matched healthy controls (mean age 14.6 y) were recruited. 3-Tesla MRI fat-water quantification was used to measure forearm muscle fat transformation in non-ambulant DMD boys compared with healthy controls. DMD boys were assessed at 4 time-points over 12 months, using 3-point Dixon MRI to measure muscle fat-fraction (f.f.). Images from ten forearm muscles were segmented and mean f.f. and cross-sectional area recorded. DMD subjects also underwent comprehensive upper limb function and force evaluation. Overall mean baseline forearm f.f. was higher in DMD than in healthy controls (pmuscle f.f. as a biomarker to monitor disease progression in the upper limb in non-ambulant DMD, with sensitivity adequate to detect group-level change over time intervals practical for use in clinical trials. Clinical validity is supported by the association of the progressive fat transformation of muscle with loss of muscle force and function.

Value of fusion of PET and MRI in the detection of intra-pelvic recurrence of gynecological tumor: comparison with 18F-FDG contrast-enhanced PET/CT and pelvic MRI.

Science.gov (United States)

Kitajima, Kazuhiro; Suenaga, Yuko; Ueno, Yoshiko; Kanda, Tomonori; Maeda, Tetsuo; Makihara, Natsuko; Ebina, Yasuhiko; Yamada, Hideto; Takahashi, Satoru; Sugimura, Kazuro

2014-01-01

To evaluate the diagnostic value of retrospective image fusion from pelvic magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography (PET) in detecting intra-pelvic recurrence of gynecological tumor. Thirty patients with a suspicion of recurrence of gynecological malignancy underwent inline contrast-enhanced PET/computed tomography (CT) and pelvic contrast-enhanced MRI for restaging. Diagnostic performance about the local recurrence, pelvic lymph node and bone metastasis and peritoneal lesion of PET/low-dose non-enhanced CT (PET/ldCT), PET/full-dose contrast-enhanced CT (PET/ceCT), contrast-enhanced MRI, and retrospective image fusion from PET and MRI (fused PET/MRI) were evaluated by two experienced readers. Final diagnoses were obtained by histopathological examinations, radiological imaging and clinical follow-up for at least 6 months. McNemar test was employed for statistical analysis. Documented positive locally recurrent disease, pelvic lymph node and bone metastases, and peritoneal dissemination were present in 53.3, 26.7, 10.0, and 16.7%, respectively. Patient-based sensitivity for detecting local recurrence, pelvic lymph node and bone metastasis and peritoneal lesion were 87.5, 87.5, 100 and 80.0%, respectively, for fused PET/MRI, 87.5, 62.5, 66.7 and 60.0%, respectively, for contrast-enhanced MRI, 62.5, 87.5, 66.7 and 80.0%, respectively, for PET/ceCT, and 50.0, 87.5, 66.7 and 60.0%, respectively, for PET/ldCT. The sensitivity of diagnosing local recurrence by fused PET/MRI was significantly better than that of PET/ldCT (p=0.041). The patient-based sensitivity, specificity and accuracy for the detection of intra-pelvic recurrence/metastasis were 91.3, 100 and 93.3% for fused PET/MRI, 82.6, 100 and 86.7% for contrast-enhanced MRI, 82.6, 100 and 86.7% for PET/ceCT and 78.3, 85.7 and 80.0% for PET/ldCT. Fused PET/MRI combines the individual advantages of MRI and PET, and is a valuable technique for assessment of intra

Cerebral microbleeds, cognitive impairment, and MRI in patients with diabetes mellitus.

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Zhou, Hong; Yang, Juan; Xie, Peihan; Dong, Yulan; You, Yong; Liu, Jincai

2017-07-01

Cerebral microbleeds (CMBs), a typical imaging manifestation marker of sporadic cerebral small vessel disease, play a critical role in vascular cognitive impairment, which is often accompanied by diabetes mellitus (DM). Hence, CMBs may, in part, be responsible for the occurrence and development of cognitive impairment in patients with diabetes. Novel magnetic resonance imaging (MRI) sequences, such as susceptibility-weighted imaging and T2*-weighted gradient-echo, have the capability of noninvasively revealing CMBs in the brain. Moreover, a correlation between CMBs and cognitive impairment in patients with diabetes has been suggested in applications of functional MRI (fMRI). Since pathological changes in the brain occur prior to observable decline in cognitive function, neuroimaging may help predict the progression of cognitive impairment in diabetic patients. In this article, we review the detection of CMBs using MRI in diabetic patients exhibiting cognitive impairment. Future studies should emphasize the development and establishment of a novel MRI protocol, including fMRI, for diabetic patients with cognitive impairment to detect CMBs. A reliable MRI protocol would also be helpful in understanding the pathological mechanisms of cognitive impairment in this important patient population. Copyright © 2017. Published by Elsevier B.V.

Comparison of post-surgical MRI presentation of the pituitary gland and its hormonal function

International Nuclear Information System (INIS)

Bladowska, J.; Sokolska, V.; Sasiadek, M.; Sozanski, T.; Bednarek-Tupikowska, G.

2010-01-01

Background: Post-surgical evaluation of the pituitary gland in MRI is difficult because of a change of anatomical conditions. It depends also on numerous other factors, including: size and expansion of a tumour before surgery, type of surgical access, quality and volume of filling material used and time of its resorption.The aim of the study was to compare MR image of the pituitary gland after surgery with clinical findings and to establish a correlation between MRI presentation of spared pituitary and its hormonal function. Material/Methods: 124 patients after resection of pituitary adenomas - 409 MRI results in total - were studied. With a 1.5-T unit, T1-weighted sagittal and coronal, enhanced and unenhanced images were obtained. Results: The pituitary gland seemed to be normal in MRI in 11 patients, 8 of them had completely regular pituitary function but in 3 of them we noticed a partial hypopituitarism. In 99 patients only a part of the pituitary gland was recognised, 53 of them had hypopituitarism but 46 of them were endocrinologically healthy. 14 patients seemed to have no persistent pituitary gland in MRI, in comparison to hormonal studies: there was panhypopituitarism in 6 and hypopituitarism in 8 cases. Conclusions: MRI presentation of post - surgical pituitary gland doesn't necessarily correlate with its hormonal function - there was a significant statistical difference. Some patients with partial pituitary seems normal hormonal function. In some cases the pituitary seem normal in MRI but these patients have hormonal disorders and need substitution therapy. (authors)

Functional-anatomic study of episodic retrieval using fMRI. I. Retrieval effort versus retrieval success.

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Buckner, R L; Koutstaal, W; Schacter, D L; Wagner, A D; Rosen, B R

1998-04-01

A number of recent functional imaging studies have identified brain areas activated during tasks involving episodic memory retrieval. The identification of such areas provides a foundation for targeted hypotheses regarding the more specific contributions that these areas make to episodic retrieval. As a beginning effort toward such an endeavor, whole-brain functional magnetic resonance imaging (fMRI) was used to examine 14 subjects during episodic word recognition in a block-designed fMRI experiment. Study conditions were manipulated by presenting either shallow or deep encoding tasks. This manipulation yielded two recognition conditions that differed with regard to retrieval effort and retrieval success: shallow encoding yielded low levels of recognition success with high levels of retrieval effort, and deep encoding yielded high levels of recognition success with low levels of effort. Many brain areas were activated in common by these two recognition conditions compared to a low-level fixation condition, including left and right prefrontal regions often detected during PET episodic retrieval paradigms (e.g., R. L. Buckner et al., 1996, J. Neurosci. 16, 6219-6235) thereby generalizing these findings to fMRI. Characterization of the activated regions in relation to the separate recognition conditions showed (1) bilateral anterior insular regions and a left dorsal prefrontal region were more active after shallow encoding, when retrieval demanded greatest effort, and (2) right anterior prefrontal cortex, which has been implicated in episodic retrieval, was most active during successful retrieval after deep encoding. We discuss these findings in relation to component processes involved in episodic retrieval and in the context of a companion study using event-related fMRI.

Resting-State Functional Connectivity-Based Biomarkers and Functional MRI-Based Neurofeedback for Psychiatric Disorders: A Challenge for Developing Theranostic Biomarkers.

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Yamada, Takashi; Hashimoto, Ryu-Ichiro; Yahata, Noriaki; Ichikawa, Naho; Yoshihara, Yujiro; Okamoto, Yasumasa; Kato, Nobumasa; Takahashi, Hidehiko; Kawato, Mitsuo

2017-10-01

Psychiatric research has been hampered by an explanatory gap between psychiatric symptoms and their neural underpinnings, which has resulted in poor treatment outcomes. This situation has prompted us to shift from symptom-based diagnosis to data-driven diagnosis, aiming to redefine psychiatric disorders as disorders of neural circuitry. Promising candidates for data-driven diagnosis include resting-state functional connectivity MRI (rs-fcMRI)-based biomarkers. Although biomarkers have been developed with the aim of diagnosing patients and predicting the efficacy of therapy, the focus has shifted to the identification of biomarkers that represent therapeutic targets, which would allow for more personalized treatment approaches. This type of biomarker (i.e., "theranostic biomarker") is expected to elucidate the disease mechanism of psychiatric conditions and to offer an individualized neural circuit-based therapeutic target based on the neural cause of a condition. To this end, researchers have developed rs-fcMRI-based biomarkers and investigated a causal relationship between potential biomarkers and disease-specific behavior using functional MRI (fMRI)-based neurofeedback on functional connectivity. In this review, we introduce a recent approach for creating a theranostic biomarker, which consists mainly of 2 parts: (1) developing an rs-fcMRI-based biomarker that can predict diagnosis and/or symptoms with high accuracy, and (2) the introduction of a proof-of-concept study investigating the relationship between normalizing the biomarker and symptom changes using fMRI-based neurofeedback. In parallel with the introduction of recent studies, we review rs-fcMRI-based biomarker and fMRI-based neurofeedback, focusing on the technological improvements and limitations associated with clinical use. © The Author 2017. Published by Oxford University Press on behalf of CINP.

Associations of resting-state fMRI functional connectivity with flow-BOLD coupling and regional vasculature.

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Tak, Sungho; Polimeni, Jonathan R; Wang, Danny J J; Yan, Lirong; Chen, J Jean

2015-04-01

There has been tremendous interest in applying functional magnetic resonance imaging-based resting-state functional connectivity (rs-fcMRI) measurements to the study of brain function. However, a lack of understanding of the physiological mechanisms of rs-fcMRI limits their ability to interpret rs-fcMRI findings. In this work, the authors examine the regional associations between rs-fcMRI estimates and dynamic coupling between the blood oxygenation level-dependent (BOLD) and cerebral blood flow (CBF), as well as resting macrovascular volume. Resting-state BOLD and CBF data were simultaneously acquired using a dual-echo pseudocontinuous arterial spin labeling (pCASL) technique, whereas macrovascular volume fraction was estimated using time-of-flight MR angiography. Functional connectivity within well-known functional networks—including the default mode, frontoparietal, and primary sensory-motor networks—was calculated using a conventional seed-based correlation approach. They found the functional connectivity strength to be significantly correlated with the regional increase in CBF-BOLD coupling strength and inversely proportional to macrovascular volume fraction. These relationships were consistently observed within all functional networks considered. Their findings suggest that highly connected networks observed using rs-fcMRI are not likely to be mediated by common vascular drainage linking distal cortical areas. Instead, high BOLD functional connectivity is more likely to reflect tighter neurovascular connections, attributable to neuronal pathways.

Morpho-Functional 1H-MRI of the Lung in COPD: Short-Term Test-Retest Reliability.

Directory of Open Access Journals (Sweden)

Bertram J Jobst

Full Text Available Non-invasive end-points for interventional trials and tailored treatment regimes in chronic obstructive pulmonary disease (COPD for monitoring regionally different manifestations of lung disease instead of global assessment of lung function with spirometry would be valuable. Proton nuclear magnetic resonance imaging (1H-MRI allows for a radiation-free assessment of regional structure and function. The aim of this study was to evaluate the short-term reproducibility of a comprehensive morpho-functional lung MRI protocol in COPD.20 prospectively enrolled COPD patients (GOLD I-IV underwent 1H-MRI of the lung at 1.5T on two consecutive days, including sequences for morphology, 4D contrast-enhanced perfusion, and respiratory mechanics. Image quality and COPD-related morphological and functional changes were evaluated in consensus by three chest radiologists using a dedicated MRI-based visual scoring system. Test-retest reliability was calculated per each individual lung lobe for the extent of large airway (bronchiectasis, wall thickening, mucus plugging and small airway abnormalities (tree in bud, peripheral bronchiectasis, mucus plugging, consolidations, nodules, parenchymal defects and perfusion defects. The presence of tracheal narrowing, dystelectasis, pleural effusion, pulmonary trunk ectasia, right ventricular enlargement and, finally, motion patterns of diaphragma and chest wall were addressed.Median global scores [10(Q1:8.00;Q3:16.00 vs.11(Q1:6.00;Q3:15.00] as well as category subscores were similar between both timepoints, and kappa statistics indicated "almost perfect" global agreement (ĸ = 0.86, 95%CI = 0.81-0.91. Most subscores showed at least "substantial" agreement of MRI1 and MRI2 (ĸ = 0.64-1.00, whereas the agreement for the diagnosis of dystelectasis/effusion (ĸ = 0.42, 95%CI = 0.00-0.93 was "moderate" and of tracheal abnormalities (ĸ = 0.21, 95%CI = 0.00-0.75 "fair". Most MRI acquisitions showed at least diagnostic quality at

Investigation of a calcium-responsive contrast agent in cellular model systems: feasibility for use as a smart molecular probe in functional MRI.

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Angelovski, Goran; Gottschalk, Sven; Milošević, Milena; Engelmann, Jörn; Hagberg, Gisela E; Kadjane, Pascal; Andjus, Pavle; Logothetis, Nikos K

2014-05-21

Responsive or smart contrast agents (SCAs) represent a promising direction for development of novel functional MRI (fMRI) methods for the eventual noninvasive assessment of brain function. In particular, SCAs that respond to Ca(2+) may allow tracking neuronal activity independent of brain vasculature, thus avoiding the characteristic limitations of current fMRI techniques. Here we report an in vitro proof-of-principle study with a Ca(2+)-sensitive, Gd(3+)-based SCA in an attempt to validate its potential use as a functional in vivo marker. First, we quantified its relaxometric response in a complex 3D cell culture model. Subsequently, we examined potential changes in the functionality of primary glial cells following administration of this SCA. Monitoring intracellular Ca(2+) showed that, despite a reduction in the Ca(2+) level, transport of Ca(2+) through the plasma membrane remained unaffected, while stimulation with ATP induced Ca(2+)-transients suggested normal cellular signaling in the presence of low millimolar SCA concentrations. SCAs merely lowered the intracellular Ca(2+) level. Finally, we estimated the longitudinal relaxation times (T1) for an idealized in vivo fMRI experiment with SCA, for extracellular Ca(2+) concentration level changes expected during intense neuronal activity which takes place upon repetitive stimulation. The values we obtained indicate changes in T1 of around 1-6%, sufficient to be robustly detectable using modern MRI methods in high field scanners. Our results encourage further attempts to develop even more potent SCAs and appropriate fMRI protocols. This would result in novel methods that allow monitoring of essential physiological processes at the cellular and molecular level.

Feasibility of shutter-speed DCE-MRI for improved prostate cancer detection.

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Li, Xin; Priest, Ryan A; Woodward, William J; Tagge, Ian J; Siddiqui, Faisal; Huang, Wei; Rooney, William D; Beer, Tomasz M; Garzotto, Mark G; Springer, Charles S

2013-01-01

The feasibility of shutter-speed model dynamic-contrast-enhanced MRI pharmacokinetic analyses for prostate cancer detection was investigated in a prebiopsy patient cohort. Differences of results from the fast-exchange-regime-allowed (FXR-a) shutter-speed model version and the fast-exchange-limit-constrained (FXL-c) standard model are demonstrated. Although the spatial information is more limited, postdynamic-contrast-enhanced MRI biopsy specimens were also examined. The MRI results were correlated with the biopsy pathology findings. Of all the model parameters, region-of-interest-averaged K(trans) difference [ΔK(trans) ≡ K(trans)(FXR-a) - K(trans)(FXL-c)] or two-dimensional K(trans)(FXR-a) vs. k(ep)(FXR-a) values were found to provide the most useful biomarkers for malignant/benign prostate tissue discrimination (at 100% sensitivity for a population of 13, the specificity is 88%) and disease burden determination. (The best specificity for the fast-exchange-limit-constrained analysis is 63%, with the two-dimensional plot.) K(trans) and k(ep) are each measures of passive transcapillary contrast reagent transfer rate constants. Parameter value increases with shutter-speed model (relative to standard model) analysis are larger in malignant foci than in normal-appearing glandular tissue. Pathology analyses verify the shutter-speed model (FXR-a) promise for prostate cancer detection. Parametric mapping may further improve pharmacokinetic biomarker performance. Copyright © 2012 Wiley Periodicals, Inc.

Non-invasive MRI detection of individual pellets in the human stomach.

Science.gov (United States)

Knörgen, Manfred; Spielmann, Rolf Peter; Abdalla, Ahmed; Metz, Hendrik; Mäder, Karsten

2010-01-01

MRI is a powerful and non-invasive method to follow the fate of oral drug delivery systems in humans. Until now, most MRI studies focused on monolithic dosage forms (tablets and capsules). Small-sized multi-particulate drug delivery systems are very difficult to detect due to the poor differentiation between the delivery system and the food. A new approach was developed to overcome the described difficulties and permit the selective imaging of small multi-particulate dosage forms within the stomach. We took advantage of the different sensitivities to susceptibility artefacts of T(2)-weighted spin-echo sequences and T(2)-weighted gradient echo pulse sequences. Using a combination of both methods within a breath hold followed by a specific mathematical image analysis involving co-registration, motion correction, voxel-by-voxel comparison of the maps from different pulse sequences and graphic 2D-/3D-presentation, we were able to obtain pictures with a high sensitivity due to susceptibility effects caused by a 1% magnetite load. By means of the new imaging sequence, single pellets as small as 1mm can be detected with high selectivity within surrounding heterogeneous food in the human stomach. The developed method greatly expands the use of MRI to study the fate of oral multi-particulate drug delivery systems and their food dependency in men. Copyright 2009 Elsevier B.V. All rights reserved.

Functional MRI and CT biomarkers in oncology

Energy Technology Data Exchange (ETDEWEB)

Winfield, J.M. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK Imaging Centre at the Institute of Cancer Research, Sutton (United Kingdom); Institute of Cancer Research and Royal Marsden Hospital, MRI Unit, Sutton (United Kingdom); Payne, G.S.; DeSouza, N.M. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK Imaging Centre at the Institute of Cancer Research, Sutton (United Kingdom)

2015-04-01

Imaging biomarkers derived from MRI or CT describe functional properties of tumours and normal tissues. They are finding increasing numbers of applications in diagnosis, monitoring of response to treatment and assessment of progression or recurrence. Imaging biomarkers also provide scope for assessment of heterogeneity within and between lesions. A wide variety of functional parameters have been investigated for use as biomarkers in oncology. Some imaging techniques are used routinely in clinical applications while others are currently restricted to clinical trials or preclinical studies. Apparent diffusion coefficient, magnetization transfer ratio and native T{sub 1} relaxation time provide information about structure and organization of tissues. Vascular properties may be described using parameters derived from dynamic contrast-enhanced MRI, dynamic contrast-enhanced CT, transverse relaxation rate (R{sub 2}*), vessel size index and relative blood volume, while magnetic resonance spectroscopy may be used to probe the metabolic profile of tumours. This review describes the mechanisms of contrast underpinning each technique and the technical requirements for robust and reproducible imaging. The current status of each biomarker is described in terms of its validation, qualification and clinical applications, followed by a discussion of the current limitations and future perspectives. (orig.)

Comparison of MRI and PET-CT in detecting the loco-regional recurrence of soft tissue sarcomas during surveillance

Energy Technology Data Exchange (ETDEWEB)

Park, Sun-Young [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Hallym University Sacred Heart Hospital, Department of Radiology, Anyang-si, Gyeonggi-do (Korea, Republic of); Chung, Hye Won [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Chae, Sun Young [University of Ulsan College of Medicine, Asan Medical Center, Department of Nuclear Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Lee, Jong-Seok [University of Ulsan College of Medicine, Asan Medical Center, Department of Orthopedic Surgery, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of)

2016-10-15

To investigate the diagnostic performance of MRI and PET-CT for the detection of loco-regional recurrences after soft tissue sarcoma (STS) excision. From Dec 2003 to Aug 2014, 394 patients with STSs, who were included in the electronic patient registry for initial or repeated surgery at our hospital, were retrospectively reviewed. We identified 152 patients who underwent regular postoperative follow-ups with both MRI and PET-CT, obtained within a 3 month period of each other. We analyzed differences in the performance of MRI and PET-CT for the diagnosis of loco-regional recurrences using McNemar's test. The receiver-operating characteristic curves and calculations of the area under the curve were used. Twenty patients were found to have a loco-regional recurrence after tumor excision. For MRI and PET-CT, the sensitivities were 90.0 and 95.0 %, and the specificities 97.7 and 95.5 %, respectively, with positive predictive values of 85.7 and 76.0 % and negative predictive values of 98.5 and 99.2 %, respectively. No significant difference was detected between the sensitivities of MRI and PET-CT (p = 0.125). The area under the receiver-operating characteristic curve for PET-CT (0.952) was not significantly greater than that for MRI (0.939; p = 0.6). MRI of the area of interest is recommended for evaluation of tumor recurrence after surgical excision of STS. PET-CT was shown to be effective for detection of STS recurrence, and comparable to MRI. However, if PET-CT or MRI findings are inconclusive, the other modality may be helpful in differentiating tumor recurrence from post-therapeutic tissue change. (orig.)

The search for neuroimaging biomarkers of Alzheimer's disease with advanced MRI techniques

International Nuclear Information System (INIS)

Li, Tie-Qiang; Wahlund, Lars-Olof

2011-01-01

The aim of this review is to examine the recent literature on using advanced magnetic resonance imaging (MRI) techniques for finding neuroimaging biomarkers that are sensitive to the detection of risks for Alzheimer's disease (AD). Since structural MRI techniques, such as brain structural volumetry and voxel based morphometry (VBM), have been widely used for AD studies and extensively reviewed, we will only briefly touch on the topics of volumetry and morphometry. The focus of the current review is about the more recent developments in the search for AD neuroimaging biomarkers with functional MRI (fMRI), resting-state functional connectivity MRI (fcMRI), diffusion tensor imaging (DTI), arterial spin-labeling (ASL), and magnetic resonance spectroscopy (MRS)

Remotely detected high-field MRI of porous samples

Science.gov (United States)

Seeley, Juliette A.; Han, Song-I.; Pines, Alexander

2004-04-01

Remote detection of NMR is a novel technique in which an NMR-active sensor surveys an environment of interest and retains memory of that environment to be recovered at a later time in a different location. The NMR or MRI information about the sensor nucleus is encoded and stored as spin polarization at the first location and subsequently moved to a different physical location for optimized detection. A dedicated probe incorporating two separate radio frequency (RF)—circuits was built for this purpose. The encoding solenoid coil was large enough to fit around the bulky sample matrix, while the smaller detection solenoid coil had not only a higher quality factor, but also an enhanced filling factor since the coil volume comprised purely the sensor nuclei. We obtained two-dimensional (2D) void space images of two model porous samples with resolution less than 1.4 mm 2. The remotely reconstructed images demonstrate the ability to determine fine structure with image quality superior to their directly detected counterparts and show the great potential of NMR remote detection for imaging applications that suffer from low sensitivity due to low concentrations and filling factor.

Gait improvement after treadmill training in ischemic stroke survivors: A critical review of functional MRI studies ☆

OpenAIRE

Xiao, Xiang; Huang, Dongfeng; O’Young, Bryan

2012-01-01

Stroke survivors often present with abnormal gait, movement training can improve the walking performance post-stroke, and functional MRI can objectively evaluate the brain functions before and after movement training. This paper analyzes the functional MRI changes in patients with ischemic stroke after treadmill training with voluntary and passive ankle dorsiflexion. Functional MRI showed that there are some changes in some regions of patients with ischemic stroke including primary sensorimot...

Comparison of X-ray, CT and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis

International Nuclear Information System (INIS)

Huang Zhenguo; Zhang Xuezhe; Hong Wen; Wang Guochun; Zhou Huiqiong; Lu Xin; Wang Wu

2011-01-01

Objective: To compare X-ray, CT, and MRI in detection of abnormal sacroiliac joint changes in patients with early stage of ankylosing spondylitis (AS). Methods: Fifty-three patients with clinical suspected early stage of AS underwent X-ray and MRI scan. MR scan sequences for the sacroiliac joints consisted of T 1 -weighted, T 2 -weighted, short time inversion recovery (STIR) and three dimensional balance turbo field echo with water selective excitation (3D-BTFE-WATS) in all patients. In 24 of the patients, fat-saturated contrast-enhanced T 1 -weighted was used. Twenty-five of 53 patients underwent CT scan. The Chi-square test was used to analyse the uniformity of bone erosions detected by X-ray, CT, and MRI. Results: Of the 106 sacroiliac joints in 53 patients, 16 sacroiliac joints with bone erosions were detected by X-ray and 63 sacroiliac joints by MRI. Of the 50 sacroiliac joints in 25 patients, 26 sacroiliac joints with bone erosions were found by CT. With regard to the detection of bone erosions, there was no difference between Cf and MRI (χ 2 =0.16, P>0.05) and there was significant difference between CT and X-ray or MRI and X-ray (χ 2 =14.44 and 17.36, P<0.05). 3D-BTFE-WATS was better than other sequences in detection of bone erosions. Acute inflammatory changes were determined by MRI, which included subchondral bone marrow edema in 32 patients, synovitis in 35 patients, fat depositions in 16 patients, enthesitis in 15 patients, capsulitis in 9 patients, and cartilaginous disruption in 31 patients. Conclusions: MRI can detect acute inflammatory changes that can not display by X-ray and CT. Compared with radiography and CT, MRI is more useful in detection of abnormal sacroiliac joint changes in patients with early stage of AS. (authors)

Breast MRI, digital mammography and breast tomosynthesis: comparison of three methods for early detection of breast cancer

Directory of Open Access Journals (Sweden)

Dragana Roganovic

2015-11-01

Full Text Available Breast cancer is the most common malignancy in women and early detection is important for its successful treatment. The aim of this study was to investigate the sensitivity and specificity of three methods for early detection of breast cancer: breast magnetic resonance imaging (MRI, digital mammography, and breast tomosynthesis in comparison to histopathology, as well as to investigate the intraindividual variability between these modalities.  We included 57 breast lesions, each detected by three diagnostic modalities: digital mammography, breast MRI, and breast tomosynthesis, and subsequently confirmed by histopathology. Breast Imaging-Reporting and Data System (BI-RADS was used for characterizing the lesions. One experienced radiologist interpreted all three diagnostic modalities. Twenty-nine of the breast lesions were malignant while 28 were benign. The sensitivity for digital mammography, breast MRI, and breast tomosynthesis, was 72.4%, 93.1%, and 100%, respectively; while the specificity was 46.4%, 60.7%, and 75%, respectively. Receiver operating characteristics (ROC curve analysis showed an overall diagnostic advantage of breast tomosynthesis over both breast MRI and digital mammography. The difference in performance between breast tomosynthesis and digital mammography was significant (p < 0.001, while the difference between breast tomosynthesis and breast MRI was not significant (p = 0.20. 

DISC1 gene and affective psychopathology: a combined structural and functional MRI study.

Science.gov (United States)

Opmeer, Esther M; van Tol, Marie-José; Kortekaas, Rudie; van der Wee, Nic J A; Woudstra, Saskia; van Buchem, Mark A; Penninx, Brenda W; Veltman, Dick J; Aleman, André

2015-02-01

The gene Disrupted-In-Schizophrenia-1 (DISC1) has been indicated as a determinant of psychopathology, including affective disorders, and shown to influence prefrontal cortex (PFC) and hippocampus functioning, regions of major interest for affective disorders. We aimed to investigate whether DISC1 differentially modulates brain function during executive and memory processing, and morphology in regions relevant for depression and anxiety disorders (affective disorders). 128 participants, with (n = 103) and without (controls; n = 25) affective disorders underwent genotyping for Ser704Cys (with Cys-allele considered as risk-allele) and structural and functional (f) Magnetic Resonance Imaging (MRI) during visuospatial planning and emotional episodic memory tasks. For both voxel-based morphometry and fMRI analyses, we investigated the effect of genotype in controls and explored genotypeXdiagnosis interactions. Results are reported at p < 0.05 FWE small volume corrected. In controls, Cys-carriers showed smaller bilateral (para)hippocampal volumes compared with Ser-homozygotes, and lower activation in the anterior cingulate cortex (ACC) and dorsolateral PFC during visuospatial planning. In anxiety patients, Cys-carriers showed larger (para)hippocampal volumes and more ACC activation during visuospatial planning. In depressive patients, no effect of genotype was observed and overall, no effect of genotype on episodic memory processing was detected. We demonstrated that Ser704Cys-genotype influences (para)hippocampal structure and functioning the dorsal PFC during executive planning, most prominently in unaffected controls. Results suggest that presence of psychopathology moderates Ser704Cys effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Can the painDETECT Questionnaire score and MRI help predict treatment outcome in rheumatoid arthritis

DEFF Research Database (Denmark)

Rifbjerg-Madsen, Signe; Christensen, Anton Wulf; Boesen, Mikael

2014-01-01

contrast-enhanced MRI (DCE-MRI) is performed. METHOD AND ANALYSIS: The painDETECT Questionnaire (PDQ), originally developed to screen for a neuropathic pain component, is applied to indicate the presence of central sensitisation. Adults diagnosed with RA are included when either (A) initiating disease......-inflammatory treatment, to explore the prognostic value of a screening questionnaire for central sensitisation, hand inflammation assessed by conventional MRI, and the interaction between them regarding treatment outcome evaluated by clinical status (DAS28-CRP). For the purpose of further exploratory analyses, dynamic...

Hypercapnic evaluation of vascular reactivity in healthy aging and acute stroke via functional MRI.

Science.gov (United States)

Raut, Ryan V; Nair, Veena A; Sattin, Justin A; Prabhakaran, Vivek

2016-01-01

Functional MRI (fMRI) is well-established for the study of brain function in healthy populations, although its clinical application has proven more challenging. Specifically, cerebrovascular reactivity (CVR), which allows the assessment of the vascular response that serves as the basis for fMRI, has been shown to be reduced in healthy aging as well as in a range of diseases, including chronic stroke. However, the timing of when this occurs relative to the stroke event is unclear. We used a breath-hold fMRI task to evaluate CVR across gray matter in a group of acute stroke patients (< 10 days from stroke; N = 22) to address this question. These estimates were compared with those from both age-matched (N = 22) and younger (N = 22) healthy controls. As expected, young controls had the greatest mean CVR, as indicated by magnitude and extent of fMRI activation; however, stroke patients did not differ from age-matched controls. Moreover, the ipsilesional and contralesional hemispheres of stroke patients did not differ with respect to any of these measures. These findings suggest that fMRI remains a valid tool within the first few days of a stroke, particularly for group fMRI studies in which findings are compared with healthy subjects of similar age. However, given the relatively high variability in CVR observed in our stroke sample, caution is warranted when interpreting fMRI data from individual patients or a small cohort. We conclude that a breath-hold task can be a useful addition to functional imaging protocols for stroke patients.

Bayesian spatiotemporal model of fMRI data using transfer functions.

Science.gov (United States)

Quirós, Alicia; Diez, Raquel Montes; Wilson, Simon P

2010-09-01

This research describes a new Bayesian spatiotemporal model to analyse BOLD fMRI studies. In the temporal dimension, we describe the shape of the hemodynamic response function (HRF) with a transfer function model. The spatial continuity and local homogeneity of the evoked responses are modelled by a Gaussian Markov random field prior on the parameter indicating activations. The proposal constitutes an extension of the spatiotemporal model presented in a previous approach [Quirós, A., Montes Diez, R. and Gamerman, D., 2010. Bayesian spatiotemporal model of fMRI data, Neuroimage, 49: 442-456], offering more flexibility in the estimation of the HRF and computational advantages in the resulting MCMC algorithm. Simulations from the model are performed in order to ascertain the performance of the sampling scheme and the ability of the posterior to estimate model parameters, as well as to check the model sensitivity to signal to noise ratio. Results are shown on synthetic data and on a real data set from a block-design fMRI experiment. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

International Nuclear Information System (INIS)

Morioka, T.; Fujii, K.; Fukui, M.; Mizushima, A.; Matsumoto, S.; Hasuo, K.; Yamamoto, T.; Tobimatsu, S.

1995-01-01

Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

Functional mapping of the sensorimotor cortex: combined use of magnetoencephalography, functional MRI, and motor evoked potentials

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Morioka, T. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fujii, K. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Fukui, M. [Dept. of Neurosurgery, Neurological Inst., Kyshu Univ., Fukuoka (Japan); Mizushima, A. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Matsumoto, S. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Hasuo, K. [Dept. of Radiology, Kyushu Univ. Fukuoka (Japan); Yamamoto, T. [Dept. of Otolaryngology, Kyushu Univ. Fukuoka (Japan); Tobimatsu, S. [Dept. of Clinical Neurophysiology, Neurological Inst., Kyushu Univ., Fukuoka (Japan)

1995-10-01

Combined use of magnetoencephalography (MEG), functional magnetic resonance imaging (f-MRI), and motor evoked potentials (MEPs) was carried out on one patient in an attempt to localise precisely a structural lesion to the central sulcus. A small cyst in the right frontoparietal region was thought to be the cause of generalised seizures in an otherwise asymptomatic woman. First the primary sensory cortex was identified with magnetic source imaging (MSI) of somatosensory evoked magnetic fields using MEG and MRI. Second, the motor area of the hand was identified using f-MRI during handsqueezing. Then transcranial magnetic stimulation localised the hand motor area on the scalp, which was mapped onto the MRI. There was a good agreement between MSI, f-MRI and MEP as to the location of the sensorimotor cortex and its relationship to the lesion. Multimodality mapping techniques may thus prove useful in the precise localisation of cortical lesions, and in the preoperative determination of the best treatment for peri-rolandic lesions. (orig.)

Synthesis of functionalized magnetite nanoparticles to use as liver targeting MRI contrast agent

International Nuclear Information System (INIS)

Yazdani, Farshad; Fattahi, Bahare; Azizi, Najmodin

2016-01-01

The aim of this research was the preparation of functionalized magnetite nanoparticles to use as a liver targeting contrast agent in magnetic resonance imaging (MRI). For this purpose, Fe_3O_4 nanoparticles were synthesized via the co-precipitation method. The synthesized nanoparticles were coated with silica via the Stober method and finally the coated nanoparticles were functionalized with mebrofenin. Formation of crystalline magnetite particles was confirmed by X-ray diffraction (XRD) analysis. The Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analyzer (EDX) of the final product showed that silica had been effectively bonded onto the surface of the magnetite nanoparticles and the coated nanoparticles functionalized with mebrofenin. The magnetic resonance imaging of the functional nanoparticles showed that the Fe_3O_4–SiO_2-mebrofenin composite is an effective MRI contrast agent for liver targeting. - Highlights: • Superparamagnetic magnetite nanoparticles have been synthesized by simple and economical method. • Preperation of functional MNPs as a MRI contrast agent for liver targeting. • Gaining a good r_2 relaxivity of the coated functional nanoparticles.

Bold-Independent Computational Entropy Assesses Functional Donut-Like Structures in Brain fMRI Images.

Science.gov (United States)

Peters, James F; Ramanna, Sheela; Tozzi, Arturo; İnan, Ebubekir

2017-01-01

We introduce a novel method for the measurement of information level in fMRI (functional Magnetic Resonance Imaging) neural data sets, based on image subdivision in small polygons equipped with different entropic content. We show how this method, called maximal nucleus clustering (MNC), is a novel, fast and inexpensive image-analysis technique, independent from the standard blood-oxygen-level dependent signals. MNC facilitates the objective detection of hidden temporal patterns of entropy/information in zones of fMRI images generally not taken into account by the subjective standpoint of the observer. This approach befits the geometric character of fMRIs. The main purpose of this study is to provide a computable framework for fMRI that not only facilitates analyses, but also provides an easily decipherable visualization of structures. This framework commands attention because it is easily implemented using conventional software systems. In order to evaluate the potential applications of MNC, we looked for the presence of a fourth dimension's distinctive hallmarks in a temporal sequence of 2D images taken during spontaneous brain activity. Indeed, recent findings suggest that several brain activities, such as mind-wandering and memory retrieval, might take place in the functional space of a four dimensional hypersphere, which is a double donut-like structure undetectable in the usual three dimensions. We found that the Rényi entropy is higher in MNC areas than in the surrounding ones, and that these temporal patterns closely resemble the trajectories predicted by the possible presence of a hypersphere in the brain.

Neurodegenerative diseases of the central motor system in MRI

International Nuclear Information System (INIS)

Alfke, K.

2005-01-01

Neurodegenerative diseases of the central motor system often lead to discrete but functionally important parenchymal abnormalities in various parts of the brain. MRI is the most sensitive imaging method to detect these abnormalities. Various neurodegenerative diseases are presented with their clinical symptoms and MRI findings. Criteria for differential diagnosis are provided as well. (orig.)

Min-max Extrapolation Scheme for Fast Estimation of 3D Potts Field Partition Functions. Application to the Joint Detection-Estimation of Brain Activity in fMRI

International Nuclear Information System (INIS)

Risser, L.; Vincent, T.; Ciuciu, P.; Risser, L.; Idier, J.; Risser, L.; Forbes, F.

2011-01-01

In this paper, we propose a fast numerical scheme to estimate Partition Functions (PF) of symmetric Potts fields. Our strategy is first validated on 2D two-color Potts fields and then on 3D two- and three-color Potts fields. It is then applied to the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated, deactivated and inactivated brain regions and to estimate region dependent hemodynamic filters. For any brain region, a specific 3D Potts field indeed embodies the spatial correlation over the hidden states of the voxels by modeling whether they are activated, deactivated or inactive. To make spatial regularization adaptive, the PFs of the Potts fields over all brain regions are computed prior to the brain activity estimation. Our approach is first based upon a classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, we propose an extrapolation method that allows us to approximate the PFs associated to the Potts fields defined over the remaining brain regions. In comparison with preexisting methods either based on a path sampling strategy or mean-field approximations, our contribution strongly alleviates the computational cost and makes spatially adaptive regularization of whole brain fMRI datasets feasible. It is also robust against grid inhomogeneities and efficient irrespective of the topological configurations of the brain regions. (authors)

Utility of vaginal and rectal contrast medium in MRI for the detection of deep pelvic endometriosis

International Nuclear Information System (INIS)

Chassang, M.; Novellas, S.; Bloch-Marcotte, C.; Chevallier, P.; Delotte, J.; Bongain, A.; Toullalan, O.

2010-01-01

To study the sensitivity of MRI performed utilising vaginal and rectal opacification with ultrasound gel in the detection of deep pelvic endometriosis. This was a prospective monocentric study. All patients evaluated by the gynaecologist for pelvic pain, endometriosis or infertility were included. Axial and sagittal T2-weighted images were performed both with and without vaginal and rectal opacification with ultrasound gel. Three radiologists, all blinded, interpreted the images with a minimum of 15 days between the two readings. MRI performance with and without vaginal and rectal opacification was evaluated by calculating sensitivity, specificity and both positive and negative predictive values. Seventy-eight patients were included. Among these, 31 patients had deep pelvic endometriosis of which 24 were confirmed by laparoscopy. Seventy-six locations of deep pelvic endometriosis were discovered on MRI. For the three reviewers there was a significant improvement in sensitivity between pre- and post-contrast MRI (p < 0.0002). Opacification of the vagina and rectum significantly improved the sensitivity of MRI for the detection of deep pelvic endometriosis by expanding the vagina and rectum, thus allowing better delineation of the pelvic organs. This was especially apparent for lesions localised to the vagina and rectovaginal septum. (orig.)

Utility of vaginal and rectal contrast medium in MRI for the detection of deep pelvic endometriosis

Energy Technology Data Exchange (ETDEWEB)

Chassang, M.; Novellas, S.; Bloch-Marcotte, C.; Chevallier, P. [Hopital Archet 2, Service d' Imagerie Diagnostique et Interventionnelle, Centre Hospitalier Regional et Universitaire de Nice, 151 route de Saint Antoine de Ginestiere, B.P. 3079, Nice Cedex 3 (France); Delotte, J.; Bongain, A. [Hopital Archet 2, Service de Gynecologie-Obstetrique, Centre Hospitalier Regional et Universitaire de Nice, 151 route de Saint Antoine de Ginestiere, B.P. 3079, Nice Cedex 3 (France); Toullalan, O. [Hopital de Cannes, Service de Gynecologie, 15 avenue des Broussailles, B.P. 264, Cannes Cedex (France)

2010-04-15

To study the sensitivity of MRI performed utilising vaginal and rectal opacification with ultrasound gel in the detection of deep pelvic endometriosis. This was a prospective monocentric study. All patients evaluated by the gynaecologist for pelvic pain, endometriosis or infertility were included. Axial and sagittal T2-weighted images were performed both with and without vaginal and rectal opacification with ultrasound gel. Three radiologists, all blinded, interpreted the images with a minimum of 15 days between the two readings. MRI performance with and without vaginal and rectal opacification was evaluated by calculating sensitivity, specificity and both positive and negative predictive values. Seventy-eight patients were included. Among these, 31 patients had deep pelvic endometriosis of which 24 were confirmed by laparoscopy. Seventy-six locations of deep pelvic endometriosis were discovered on MRI. For the three reviewers there was a significant improvement in sensitivity between pre- and post-contrast MRI (p < 0.0002). Opacification of the vagina and rectum significantly improved the sensitivity of MRI for the detection of deep pelvic endometriosis by expanding the vagina and rectum, thus allowing better delineation of the pelvic organs. This was especially apparent for lesions localised to the vagina and rectovaginal septum. (orig.)

Multiparametric MRI in the assessment of response of rectal cancer to neoadjuvant chemoradiotherapy: A comparison of morphological, volumetric and functional MRI parameters

International Nuclear Information System (INIS)

Hoetker, Andreas M.; Tarlinton, Lisa; Gollub, Marc J.; Mazaheri, Yousef; Woo, Kaitlin M.; Goenen, Mithat; Saltz, Leonard B.; Goodman, Karyn A.; Garcia-Aguilar, Julio

2016-01-01

To compare morphological and functional MRI metrics and determine which ones perform best in assessing response to neoadjuvant chemoradiotherapy (CRT) in rectal cancer. This retrospective study included 24 uniformly-treated patients with biopsy-proven rectal adenocarcinoma who underwent MRI, including diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) sequences, before and after completion of CRT. On all MRI exams, two experienced readers independently measured longest and perpendicular tumour diameters, tumour volume, tumour regression grade (TRG) and tumour signal intensity ratio on T2-weighted imaging, as well as tumour volume and apparent diffusion coefficient on DW-MRI and tumour volume and transfer constant K"t"r"a"n"s on DCE-MRI. These metrics were correlated with histopathological percent tumour regression in the resected specimen (%TR). Inter-reader agreement was assessed using the concordance correlation coefficient (CCC). For both readers, post-treatment DW-MRI and DCE-MRI volumetric tumour assessments were significantly associated with %TR; DCE-MRI volumetry showed better inter-reader agreement (CCC=0.700) than DW-MRI volumetry (CCC=0.292). For one reader, mrTRG, post-treatment T2 tumour volumetry and assessments of volume change made with T2, DW-MRI and DCE-MRI were also significantly associated with %TR. Tumour volumetry on post-treatment DCE-MRI and DW-MRI correlated well with %TR, with DCE-MRI volumetry demonstrating better inter-reader agreement. (orig.)

Multiparametric MRI in the assessment of response of rectal cancer to neoadjuvant chemoradiotherapy: A comparison of morphological, volumetric and functional MRI parameters

Energy Technology Data Exchange (ETDEWEB)

Hoetker, Andreas M. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Universitaetsmedizin Mainz, Department of Diagnostic and Interventional Radiology, Mainz (Germany); Tarlinton, Lisa; Gollub, Marc J. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Mazaheri, Yousef [Memorial Sloan Kettering Cancer Center, Department of Medical Physics, New York, NY (United States); Woo, Kaitlin M.; Goenen, Mithat [Memorial Sloan Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Saltz, Leonard B. [Memorial Sloan Kettering Cancer Center, Department of Medicine, Gastrointestinal Oncology Service, New York, NY (United States); Goodman, Karyn A. [Memorial Sloan Kettering Cancer Center, Department of Radiation Oncology, New York, NY (United States); Garcia-Aguilar, Julio [Memorial Sloan Kettering Cancer Center, Department of Surgery, New York, NY (United States)

2016-12-15

To compare morphological and functional MRI metrics and determine which ones perform best in assessing response to neoadjuvant chemoradiotherapy (CRT) in rectal cancer. This retrospective study included 24 uniformly-treated patients with biopsy-proven rectal adenocarcinoma who underwent MRI, including diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) sequences, before and after completion of CRT. On all MRI exams, two experienced readers independently measured longest and perpendicular tumour diameters, tumour volume, tumour regression grade (TRG) and tumour signal intensity ratio on T2-weighted imaging, as well as tumour volume and apparent diffusion coefficient on DW-MRI and tumour volume and transfer constant K{sup trans} on DCE-MRI. These metrics were correlated with histopathological percent tumour regression in the resected specimen (%TR). Inter-reader agreement was assessed using the concordance correlation coefficient (CCC). For both readers, post-treatment DW-MRI and DCE-MRI volumetric tumour assessments were significantly associated with %TR; DCE-MRI volumetry showed better inter-reader agreement (CCC=0.700) than DW-MRI volumetry (CCC=0.292). For one reader, mrTRG, post-treatment T2 tumour volumetry and assessments of volume change made with T2, DW-MRI and DCE-MRI were also significantly associated with %TR. Tumour volumetry on post-treatment DCE-MRI and DW-MRI correlated well with %TR, with DCE-MRI volumetry demonstrating better inter-reader agreement. (orig.)

Functional MRI of human hypothalamic responses following glucose ingestion

NARCIS (Netherlands)

Smeets, P.A.M.; Graaf, C. de; Stafleu, A.; Osch, M.J.P. van; Grond, J. van der

2005-01-01

The hypothalamus is intimately involved in the regulation of food intake, integrating multiple neural and hormonal signals. Several hypothalamic nuclei contain glucose-sensitive neurons, which play a crucial role in energy homeostasis. Although a few functional magnetic resonance imaging (fMRI)

Functional cine MR imaging for the detection and mapping of intraabdominal adhesions: method and surgical correlation

Energy Technology Data Exchange (ETDEWEB)

Buhmann-Kirchhoff, Sonja; Reiser, Maximilian; Lienemann, Andreas [University Hospital Grosshadern, Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany); Lang, Reinhold; Steitz, Heinrich O.; Jauch, Karl W. [University Hospital Munich-Grosshadern, Department of Surgery, Munich (Germany); Kirchhoff, Chlodwig [University Hospital Munich-Innenstadt, Department of Surgery, Munich (Germany)

2008-06-15

The purpose of this study was to evaluate the presence and localization of intraabdominal adhesions using functional cine magnetic resonance imaging (MRI) and to correlate the MR findings with intraoperative results. In a retrospective study, patients who had undergone previous abdominal surgery with suspected intraabdominal adhesions were examined. A true fast imaging with steady state precession sequence in transverse/sagittal orientation was used for a section-by-section dynamic depiction of visceral slide on a 1.5-Tesla system. After MRI, all patients underwent anew surgery. A nine-segment abdominal map was used to document the location and type of the adhesions. The intraoperative results were taken as standard of reference. Ninety patients were enrolled. During surgery 71 adhesions were detected, MRI depicted 68 intraabdominal adhesions. The most common type of adhesion in MRI was found between the anterior abdominal wall and small bowel loops (n = 22, 32.5%) and between small bowel loops and pelvic organs (n = 14, 20.6%). Comparing MRI with the intraoperative findings, sensitivity varied between 31 and 75% with a varying specificity between 65 and 92% in the different segments leading to an overall MRI accuracy of 89%. Functional cine MRI proved to be a useful examination technique for the identification of intraabdominal adhesions in patients with acute or chronic pain and corresponding clinical findings providing accurate results. However, no differentiation for symptomatic versus asymptomatic adhesions is possible. (orig.)

Mapping of cognitive functions in chronic intractable epilepsy: Role of fMRI

International Nuclear Information System (INIS)

Chaudhary, Kapil; Kumaran, S Senthil; Chandra, Sarat P; Wadhawan, Ashima Nehra; Tripathi, Manjari

2014-01-01

Functional magnetic resonance imaging (fMRI), a non-invasive technique with high spatial resolution and blood oxygen level dependent (BOLD) contrast, has been applied to localize and map cognitive functions in the clinical condition of chronic intractable epilepsy. fMRI was used to map the language and memory network in patients of chronic intractable epilepsy pre- and post-surgery. After obtaining approval from the institutional ethics committee, six patients with intractable epilepsy with an equal number of age-matched controls were recruited in the study. A 1.5 T MR scanner with 12-channel head coil, integrated with audio-visual fMRI accessories was used. Echo planar imaging sequence was used for BOLD studies. There were two sessions in TLE (pre- and post-surgery). In TLE patients, BOLD activation increased post-surgery in comparison of pre-surgery in inferior frontal gyrus (IFG), middle frontal gyrus (MFG), and superior temporal gyrus (STG), during semantic lexical, judgment, comprehension, and semantic memory tasks. Functional MRI is useful to study the basic concepts related to language and memory lateralization in TLE and guide surgeons for preservation of important brain areas during ATLR. This will help in understanding future directions for the diagnosis and treatment of such disease

Mapping of cognitive functions in chronic intractable epilepsy: Role of fMRI

Directory of Open Access Journals (Sweden)

Kapil Chaudhary

2014-01-01

Full Text Available Background: Functional magnetic resonance imaging (fMRI, a non-invasive technique with high spatial resolution and blood oxygen level dependent (BOLD contrast, has been applied to localize and map cognitive functions in the clinical condition of chronic intractable epilepsy. Purpose: fMRI was used to map the language and memory network in patients of chronic intractable epilepsy pre- and post-surgery. Materials and Methods: After obtaining approval from the institutional ethics committee, six patients with intractable epilepsy with an equal number of age-matched controls were recruited in the study. A 1.5 T MR scanner with 12-channel head coil, integrated with audio-visual fMRI accessories was used. Echo planar imaging sequence was used for BOLD studies. There were two sessions in TLE (pre- and post-surgery. Results: In TLE patients, BOLD activation increased post-surgery in comparison of pre-surgery in inferior frontal gyrus (IFG, middle frontal gyrus (MFG, and superior temporal gyrus (STG, during semantic lexical, judgment, comprehension, and semantic memory tasks. Conclusion: Functional MRI is useful to study the basic concepts related to language and memory lateralization in TLE and guide surgeons for preservation of important brain areas during ATLR. This will help in understanding future directions for the diagnosis and treatment of such disease.

Estimation of gas and tissue lung volumes by MRI: functional approach of lung imaging.

Science.gov (United States)

Qanadli, S D; Orvoen-Frija, E; Lacombe, P; Di Paola, R; Bittoun, J; Frija, G

1999-01-01

The purpose of this work was to assess the accuracy of MRI for the determination of lung gas and tissue volumes. Fifteen healthy subjects underwent MRI of the thorax and pulmonary function tests [vital capacity (VC) and total lung capacity (TLC)] in the supine position. MR examinations were performed at inspiration and expiration. Lung volumes were measured by a previously validated technique on phantoms. Both individual and total lung volumes and capacities were calculated. MRI total vital capacity (VC(MRI)) was compared with spirometric vital capacity (VC(SP)). Capacities were correlated to lung volumes. Tissue volume (V(T)) was estimated as the difference between the total lung volume at full inspiration and the TLC. No significant difference was seen between VC(MRI) and VC(SP). Individual capacities were well correlated (r = 0.9) to static volume at full inspiration. The V(T) was estimated to be 836+/-393 ml. This preliminary study demonstrates that MRI can accurately estimate lung gas and tissue volumes. The proposed approach appears well suited for functional imaging of the lung.

Real-time MRI navigated US: Role in diagnosis and guided biopsy of incidental breast lesions and axillary lymph nodes detected on breast MRI but not on second look US

Energy Technology Data Exchange (ETDEWEB)

Pons, Elena Pastor, E-mail: elenapastorpons@gmail.com; Azcón, Francisco Miras, E-mail: frmiaz00@gmail.com; Casas, María Culiañez, E-mail: mariacc1980@gmail.com; Meca, Salvador Martínez, E-mail: isalvaa@hotmail.com; Espona, José Luis García, E-mail: gespona@hotmail.com

2014-06-15

Objectives: To prospectively evaluate the accuracy of real-time ultrasound combined with supine-MRI using volume navigation technique (RtMR-US) in diagnosis and biopsy of incidental breast lesions (ILSM) and axillary lymph nodes (LNSM) suspicious of malignancy on contrast enhanced magnetic resonance imaging (CE-MRI). Materials and methods: Five hundred and seventy-seven women were examined using breast CE-MRI. Those with incidental breast lesions not identified after second-look ultrasound (US) were recruited for RtMR-US. Biopsy was performed in ILSM. Breast lesions were categorized with BI-RADS system and Fisher’ exact test. Axillary lymph nodes morphology was described. To assess efficacy of RtMR-US, diagnostic accuracy, sensitivity, specificity, detection rate and Kappa index of conventional-US and RtMR-US were calculated. Results: Forty-three lesions were detected on CE-MRI before navigation. Eighteen were carcinomas and 25 ILSM. Of these, 21 underwent a RtMR-US. Detection rate on RtMR-US (90.7%) was higher than on conventional-US (43%) (p < 0.001). Agreement between both techniques was low (k = 0.138). Twenty ILSM and 2 LNSM were biopsied. Sixty-five percent were benign (100% of BI-RADS3 and 56% of BI-RADS4-5). Diagnostic performance of RtMR-US identifying malignant nodules for overall lesions and for the subgroup of ILSM was respectively: sensitivity 96.3% and 100%, specificity 18.8% and 30.7%, positive predictive value 66.7% and 43.7%, negative predictive value 75% and 100%. In addition RtMR-US enabled biopsy of 2 metastatic lymph nodes. Conclusions: Real time-US with supine-MRI using a volume navigation technique increases the detection of ILSM. RtMR-US may be used to detect occult breast carcinomas and to assess cancer extension, preventing unnecessary MRI-guided biopsies and sentinel lymph node biopsies. Incidental lesions BI-RADS 3 non-detected on conventional-US are probably benign.

Computer-aided detection in breast MRI : a systematic review and meta-analysis

NARCIS (Netherlands)

Dorrius, Monique D.; Jansen-van der Weide, Marijke C.; van Ooijen, Peter M. A.; Pijnappel, Ruud M.; Oudkerk, Matthijs

To evaluate the additional value of computer-aided detection (CAD) in breast MRI by assessing radiologists' accuracy in discriminating benign from malignant breast lesions. A literature search was performed with inclusion of relevant studies using a commercially available CAD system with automatic

Machine learning algorithm accurately detects fMRI signature of vulnerability to major depression.

Science.gov (United States)

Sato, João R; Moll, Jorge; Green, Sophie; Deakin, John F W; Thomaz, Carlos E; Zahn, Roland

2015-08-30

Standard functional magnetic resonance imaging (fMRI) analyses cannot assess the potential of a neuroimaging signature as a biomarker to predict individual vulnerability to major depression (MD). Here, we use machine learning for the first time to address this question. Using a recently identified neural signature of guilt-selective functional disconnection, the classification algorithm was able to distinguish remitted MD from control participants with 78.3% accuracy. This demonstrates the high potential of our fMRI signature as a biomarker of MD vulnerability. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

Comparison of thallium-201 SPET and CT/MRI in the detection of residual/recurrent squamous cell carcinoma of the oral cavity

International Nuclear Information System (INIS)

Lee, Jong-Kang; Tyan, Yeu-Sheng; Huang, Wen-Sheng

2004-01-01

This study was designed to compare the effectiveness of thallium-201 single-photon emission tomography (SPET) and conventional imaging, comprising computed tomography (CT) and magnetic resonance imaging (MRI), in the detection of residual/recurrent squamous cell carcinoma (SCC) of the oral cavity. Thirty-two patients with clinically suspected recurrent SCC of the oral cavity were recruited. All patients underwent 201 Tl SPET and CT or MRI within 2 weeks. The final diagnoses were based on the histology of the biopsy specimen. 201 Tl SPET and CT/MRI both accurately detected 17 of 18 residual/recurrent tumours. CT/MRI yielded eight false-positive studies, whereas 201 Tl SPET successfully excluded all tumours. The sensitivity, specificity, positive and negative predictive values and accuracy of 201 Tl SPET for the detection of recurrent oral SCC were 94%, 100%, 100%, 93% and 97%, respectively. The sensitivity, specificity, positive and negative predictive values and accuracy of CT/MRI for the detection of recurrent oral SCC were 94%, 43%, 68%, 86% and 72%, respectively. Thallium-201 SPET is more accurate than conventional imaging (CT or MRI) in differentiating residual/recurrent oral SCC from post-therapy changes. (orig.)

Upper Limb Evaluation in Duchenne Muscular Dystrophy: Fat-Water Quantification by MRI, Muscle Force and Function Define Endpoints for Clinical Trials.

Directory of Open Access Journals (Sweden)

Valeria Ricotti

Full Text Available A number of promising experimental therapies for Duchenne muscular dystrophy (DMD are emerging. Clinical trials currently rely on invasive biopsies or motivation-dependent functional tests to assess outcome. Quantitative muscle magnetic resonance imaging (MRI could offer a valuable alternative and permit inclusion of non-ambulant DMD subjects. The aims of our study were to explore the responsiveness of upper-limb MRI muscle-fat measurement as a non-invasive objective endpoint for clinical trials in non-ambulant DMD, and to investigate the relationship of these MRI measures to those of muscle force and function.15 non-ambulant DMD boys (mean age 13.3 y and 10 age-gender matched healthy controls (mean age 14.6 y were recruited. 3-Tesla MRI fat-water quantification was used to measure forearm muscle fat transformation in non-ambulant DMD boys compared with healthy controls. DMD boys were assessed at 4 time-points over 12 months, using 3-point Dixon MRI to measure muscle fat-fraction (f.f.. Images from ten forearm muscles were segmented and mean f.f. and cross-sectional area recorded. DMD subjects also underwent comprehensive upper limb function and force evaluation.Overall mean baseline forearm f.f. was higher in DMD than in healthy controls (p<0.001. A progressive f.f. increase was observed in DMD over 12 months, reaching significance from 6 months (p<0.001, n = 7, accompanied by a significant loss in pinch strength at 6 months (p<0.001, n = 9 and a loss of upper limb function and grip force observed over 12 months (p<0.001, n = 8.These results support the use of MRI muscle f.f. as a biomarker to monitor disease progression in the upper limb in non-ambulant DMD, with sensitivity adequate to detect group-level change over time intervals practical for use in clinical trials. Clinical validity is supported by the association of the progressive fat transformation of muscle with loss of muscle force and function.

Radiomic features for prostate cancer detection on MRI differ between the transition and peripheral zones: Preliminary findings from a multi-institutional study.

Science.gov (United States)

Ginsburg, Shoshana B; Algohary, Ahmad; Pahwa, Shivani; Gulani, Vikas; Ponsky, Lee; Aronen, Hannu J; Boström, Peter J; Böhm, Maret; Haynes, Anne-Maree; Brenner, Phillip; Delprado, Warick; Thompson, James; Pulbrock, Marley; Taimen, Pekka; Villani, Robert; Stricker, Phillip; Rastinehad, Ardeshir R; Jambor, Ivan; Madabhushi, Anant

2017-07-01

To evaluate in a multi-institutional study whether radiomic features useful for prostate cancer (PCa) detection from 3 Tesla (T) multi-parametric MRI (mpMRI) in the transition zone (TZ) differ from those in the peripheral zone (PZ). 3T mpMRI, including T2-weighted (T2w), apparent diffusion coefficient (ADC) maps, and dynamic contrast-enhanced MRI (DCE-MRI), were retrospectively obtained from 80 patients at three institutions. This study was approved by the institutional review board of each participating institution. First-order statistical, co-occurrence, and wavelet features were extracted from T2w MRI and ADC maps, and contrast kinetic features were extracted from DCE-MRI. Feature selection was performed to identify 10 features for PCa detection in the TZ and PZ, respectively. Two logistic regression classifiers used these features to detect PCa and were evaluated by area under the receiver-operating characteristic curve (AUC). Classifier performance was compared with a zone-ignorant classifier. Radiomic features that were identified as useful for PCa detection differed between TZ and PZ. When classification was performed on a per-voxel basis, a PZ-specific classifier detected PZ tumors on an independent test set with significantly higher accuracy (AUC = 0.61-0.71) than a zone-ignorant classifier trained to detect cancer throughout the entire prostate (P  0.14) were obtained for all institutions. A zone-aware classifier significantly improves the accuracy of cancer detection in the PZ. 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:184-193. © 2016 International Society for Magnetic Resonance in Medicine.

Differentiating between bipolar and unipolar depression in functional and structural MRI studies.

Science.gov (United States)

Han, Kyu-Man; De Berardis, Domenico; Fornaro, Michele; Kim, Yong-Ku

2018-03-28

Distinguishing depression in bipolar disorder (BD) from unipolar depression (UD) solely based on clinical clues is difficult, which has led to the exploration of promising neural markers in neuroimaging measures for discriminating between BD depression and UD. In this article, we review structural and functional magnetic resonance imaging (MRI) studies that directly compare UD and BD depression based on neuroimaging modalities including functional MRI studies on regional brain activation or functional connectivity, structural MRI on gray or white matter morphology, and pattern classification analyses using a machine learning approach. Numerous studies have reported distinct functional and structural alterations in emotion- or reward-processing neural circuits between BD depression and UD. Different activation patterns in neural networks including the amygdala, anterior cingulate cortex (ACC), prefrontal cortex (PFC), and striatum during emotion-, reward-, or cognition-related tasks have been reported between BD and UD. A stronger functional connectivity pattern in BD was pronounced in default mode and in frontoparietal networks and brain regions including the PFC, ACC, parietal and temporal regions, and thalamus compared to UD. Gray matter volume differences in the ACC, hippocampus, amygdala, and dorsolateral prefrontal cortex (DLPFC) have been reported between BD and UD, along with a thinner DLPFC in BD compared to UD. BD showed reduced integrity in the anterior part of the corpus callosum and posterior cingulum compared to UD. Several studies performed pattern classification analysis using structural and functional MRI data to distinguish between UD and BD depression using a supervised machine learning approach, which yielded a moderate level of accuracy in classification. Copyright © 2018 Elsevier Inc. All rights reserved.

Community structure in networks of functional connectivity: resolving functional organization in the rat brain with pharmacological MRI.

Science.gov (United States)

Schwarz, Adam J; Gozzi, Alessandro; Bifone, Angelo

2009-08-01

In the study of functional connectivity, fMRI data can be represented mathematically as a network of nodes and links, where image voxels represent the nodes and the connections between them reflect a degree of correlation or similarity in their response. Here we show that, within this framework, functional imaging data can be partitioned into 'communities' of tightly interconnected voxels corresponding to maximum modularity within the overall network. We evaluated this approach systematically in application to networks constructed from pharmacological MRI (phMRI) of the rat brain in response to acute challenge with three different compounds with distinct mechanisms of action (d-amphetamine, fluoxetine, and nicotine) as well as vehicle (physiological saline). This approach resulted in bilaterally symmetric sub-networks corresponding to meaningful anatomical and functional connectivity pathways consistent with the purported mechanism of action of each drug. Interestingly, common features across all three networks revealed two groups of tightly coupled brain structures that responded as functional units independent of the specific neurotransmitter systems stimulated by the drug challenge, including a network involving the prefrontal cortex and sub-cortical regions extending from the striatum to the amygdala. This finding suggests that each of these networks includes general underlying features of the functional organization of the rat brain.

Secretin-stimulated MRI characterization of pancreatic morphology and function in patients with chronic pancreatitis.

Science.gov (United States)

Madzak, Adnan; Olesen, Søren Schou; Haldorsen, Ingfrid Salvesen; Drewes, Asbjørn Mohr; Frøkjær, Jens Brøndum

Chronic pancreatitis (CP) is characterized by abnormal pancreatic morphology and impaired endocrine and exocrine function. However, little is known about the relationship between pancreatic morphology and function, and also the association with the etiology and clinical manifestations of CP. The aim was to explore pancreatic morphology and function with advanced MRI in patients with CP and healthy controls (HC) METHODS: Eighty-two patients with CP and 22 HC were enrolled in the study. Morphological imaging parameters included pancreatic main duct diameter, gland volume, fat signal fraction and apparent diffusion coefficient (ADC) values. Functional secretin-stimulated MRI (s-MRI) parameters included pancreatic secretion (bowel fluid volume) and changes in pancreatic ADC value before and after secretin stimulation. Patients were classified according to the modified Cambridge and M-ANNHEIM classification system and fecal elastase was collected. All imaging parameters differentiated CP patients from HC; however, correlations between morphological and functional parameters in CP were weak. Patients with alcoholic and non-alcoholic etiology had comparable s-MRI findings. Fecal elastase was positively correlated to pancreatic gland volume (r = 0.68, P = 0.0016) and negatively correlated to Cambridge classification (r = -0.35, P pancreatic gland volume was significantly decreased in the severe stages of CP (P = 0.001). S-MRI provides detailed information about pancreatic morphology and function and represents a promising non-invasive imaging method to characterize pancreatic pathophysiology and may enable monitoring of disease progression in patients with CP. Copyright © 2017 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Hypercapnic evaluation of vascular reactivity in healthy aging and acute stroke via functional MRI

Directory of Open Access Journals (Sweden)

Ryan V. Raut

2016-01-01

Full Text Available Functional MRI (fMRI is well-established for the study of brain function in healthy populations, although its clinical application has proven more challenging. Specifically, cerebrovascular reactivity (CVR, which allows the assessment of the vascular response that serves as the basis for fMRI, has been shown to be reduced in healthy aging as well as in a range of diseases, including chronic stroke. However, the timing of when this occurs relative to the stroke event is unclear. We used a breath-hold fMRI task to evaluate CVR across gray matter in a group of acute stroke patients (<10 days from stroke; N = 22 to address this question. These estimates were compared with those from both age-matched (N = 22 and younger (N = 22 healthy controls. As expected, young controls had the greatest mean CVR, as indicated by magnitude and extent of fMRI activation; however, stroke patients did not differ from age-matched controls. Moreover, the ipsilesional and contralesional hemispheres of stroke patients did not differ with respect to any of these measures. These findings suggest that fMRI remains a valid tool within the first few days of a stroke, particularly for group fMRI studies in which findings are compared with healthy subjects of similar age. However, given the relatively high variability in CVR observed in our stroke sample, caution is warranted when interpreting fMRI data from individual patients or a small cohort. We conclude that a breath-hold task can be a useful addition to functional imaging protocols for stroke patients.

Diagnostic reliability of 3.0-T MRI for detecting osseous abnormalities of the temporomandibular joint.

Science.gov (United States)

Sawada, Kunihiko; Amemiya, Toshihiko; Hirai, Shigenori; Hayashi, Yusuke; Suzuki, Toshihiro; Honda, Masahiko; Sisounthone, Johnny; Matsumoto, Kunihito; Honda, Kazuya

2018-01-01

We compared the diagnostic reliability of 3.0-T magnetic resonance imaging (MRI) for detection of osseous abnormalities of the temporomandibular joint (TMJ) with that of the gold standard, cone-beam computed tomography (CBCT). Fifty-six TMJs were imaged with CBCT and MRI, and images of condyles and fossae were independently assessed for the presence of osseous abnormalities. The accuracy, sensitivity, and specificity of 3.0-T MRI were 0.88, 1.0, and 0.73, respectively, in condyle evaluation and 0.91, 0.75, and 0.95 in fossa evaluation. The McNemar test showed no significant difference (P > 0.05) between MRI and CBCT in the evaluation of osseous abnormalities in condyles and fossae. The present results indicate that 3.0-T MRI is equal to CBCT in the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

Improved detection of localized prostate cancer using co-registered MRI and {sup 11}C-acetate PET/CT

Energy Technology Data Exchange (ETDEWEB)

Jambor, Ivan, E-mail: ivjamb@utu.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); 2nd Department of Radiology, Comenius University and St. Elisabeth Oncology Institute, Bratislava (Slovakia); Turku PET Centre, University of Turku, Turku (Finland); Borra, Ronald, E-mail: ronald.borra@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Turku PET Centre, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); Kemppainen, Jukka, E-mail: Jukka.Kemppainen@tyks.fi [Turku PET Centre, University of Turku, Turku (Finland); Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku (Finland); Lepomaeki, Virva, E-mail: Virva.Lepomaki@tyks.fi [Turku PET Centre, University of Turku, Turku (Finland); Parkkola, Riitta, E-mail: Riitta.Parkkola@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Turku PET Centre, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); Dean, Kirsti, E-mail: Kirsti.Dean@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); Alanen, Kalle, E-mail: Kalle.Alanen@tyks.fi [Department of Pathology, Turku University Hospital, Turku (Finland); Arponen, Eveliina, E-mail: Eveliina.Arponen@utu.fi [Turku PET Centre, University of Turku, Turku (Finland); Nurmi, Martti, E-mail: Martti.Nurmi@tyks.fi [Department of Surgery, Division of Urology, Turku University Hospital, Turku (Finland); Aronen, Hannu J., E-mail: Hannu.Aronen@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); and others

2012-11-15

Objectives: We aimed to study the ability of contrast enhanced MRI at 1.5 T and {sup 11}C-acetate PET/CT, both individually and using fused data, to detect localized prostate cancer. Methods: Thirty-six men with untreated prostate cancer and negative for metastatic disease on pelvic CT and bone scan were prospectively enrolled. A pelvic {sup 11}C-acetate PET/CT scan was performed in all patients, and a contrast enhanced MRI scan in 33 patients (6 examinations using both endorectal coil and surface coils, and 27 examinations using surface coils only). After the imaging studies 10 patients underwent prostatectomy and 26 were treated by image guided external beam radiation treatment. Image fusion of co-registered PET and MRI data was performed based on anatomical landmarks visible on CT and MRI using an advanced in-house developed software package. PET/CT, MRI and fused PET/MRI data were evaluated visually and compared with biopsy findings on a lobar level, while a sextant approach was used for patients undergoing prostatectomy. Results: When using biopsy samples as method of reference, the sensitivity, specificity and accuracy for visual detection of prostate cancer on a lobar level by contrast enhanced MRI was 85%, 37%, 73% and that of {sup 11}C-acetate PET/CT 88%, 41%, 74%, respectively. Fusion of PET with MRI data increased sensitivity, specificity and accuracy to 90%, 72% and 85%, respectively. Conclusions: Fusion of sequentially obtained PET/CT and MRI data for the localization of prostate cancer is feasible and superior to the performance of each individual modality alone.

Detection of angiogenesis-dependent parameters by functional MRI: Correlation between histomorphology and evaluation of clinical relevance as prognostic factor for the example of cervical carcinoma

International Nuclear Information System (INIS)

Hawighorst, H.; Knopp, M.V.; Schoenberg, S.O.; Essig, M.; Kaick, G. van; Schaeffer, U.; Knapstein, P.G.; Weikel, W.

1998-01-01

Purpose: Purpose of this study is to compare functional MRI parameters with histomorphological markers of tumor microvessel density (MVD) and permeability (vascular endothelial growth factor) and to determine the ultimate value of both approaches by correlation with disease outcome in patients with primary cancer of the uterine cervix. Method: Pharmacokinetic parameters were calculated from contrast-enhanced dynamic MR imaging series in 37 patients with biopsy-proven primary cervical cancer. On the operative whole mount specimens, histomorphological markers of tumor angiogenesis (MVD, VEGF) were compared with the MRI-derived parameters. For MRI and histomorphological data, Kaplan-Meier survival curves were calculated and compared using logrank statistics. Results: Significant (p [de

Real-time virtual sonography (RVS)-guided vacuum-assisted breast biopsy for lesions initially detected with breast MRI.

Science.gov (United States)

Uematsu, Takayoshi

2013-12-01

To report on our initial experiences with a new method of real-time virtual sonography (RVS)-guided 11-gauge vacuum-assisted breast biopsy for lesions that were initially detected with breast MRI. RVS-guided 11-gauge vacuum-assisted biopsy is performed when a lesion with suspicious characteristics is initially detected with breast MRI and is occult on mammography, sonography, and physical examination. Live sonographic images were co-registered to the previously loaded second-look spine contrast-enhanced breast MRI volume data to correlate the sonography and MR images. Six lesions were examined in six consecutive patients scheduled to undergo RVS-guided 11-gauge vacuum-assisted biopsy. One patient was removed from the study because of non-visualization of the lesion in the second-look spine contrast-enhanced breast MRI. Five patients with non-mass enhancement lesions were biopsied. The lesions ranged in size from 9 to 13 mm (mean 11 mm). The average procedural time, including the sonography and MR image co-registration time, was 25 min. All biopsies resulted in tissue retrieval. One was fibroadenomatous nodules, and those of four were fibrocystic changes. There were no complications during or after the procedures. RVS-guided 11-gauge vacuum-assisted breast biopsies provide a safe and effective method for the examination of suspicious lesions initially detected with MRI.

Functional cine MRI of the abdomen for the assessment of implanted synthetic mesh in patients after incisional hernia repair: initial results

Energy Technology Data Exchange (ETDEWEB)

Fischer, Tanja [Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany); Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Klinikum Innenstadt, Munich (Germany); Ladurner, Roland; Mussack, Thomas [Ludwig-Maximilians-University Munich, Department of Surgery and Traumatology, Klinikum Innenstadt, Munich (Germany); Gangkofer, Alexander; Reiser, Maximilian; Lienemann, Andreas [Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany)

2007-12-15

The aim of our study was to develop a method that allows the vizualiation and evaluation of implanted mesh in patients after incisional hernia repair with MRI. Furthermore, we assessed problems typically related with mesh implantation like adhesions and muscular atrophy. We enrolled 28 patients after incisional hernia repair. In 10 patients mesh implantation was done by laparoscopy (expanded polytetrafluoroethylene=ePTFE mesh) and in 18 by laparotomy (polypropylene mesh). Functional MRI was performed on a 1.5-T system in supine position. Sagittal and axial TrueFISP images of the entire abdomen were acquired with the patient repeatedly straining. Evaluation included: correct position and intact fixation of the mesh, furthermore visceral adhesions, recurrent hernia and atrophy of the rectus muscle. The ePTFE mesh was visible in all cases; the polypropylene mesh was not detectable. In seven of the ten ePTFE meshes the fixation was not intact; two recurrent hernias were detected. Twenty of 28 patients had intraabdominal adhesions. In 5 cases mobility of the abdominal wall was reduced, and 16 patients showed an atropy of the rectus muscle. Functional cine MRI is a suitable method for follow-up studies in patients after hernia repair. ePTFE meshes can be visualized directly, and typical complications like intestinal adhesions and abdominal wall dysmotility can be assessed reliably. (orig.)

Degree of contribution (DoC) feature selection algorithm for structural brain MRI volumetric features in depression detection.

Science.gov (United States)

Kipli, Kuryati; Kouzani, Abbas Z

2015-07-01

Accurate detection of depression at an individual level using structural magnetic resonance imaging (sMRI) remains a challenge. Brain volumetric changes at a structural level appear to have importance in depression biomarkers studies. An automated algorithm is developed to select brain sMRI volumetric features for the detection of depression. A feature selection (FS) algorithm called degree of contribution (DoC) is developed for selection of sMRI volumetric features. This algorithm uses an ensemble approach to determine the degree of contribution in detection of major depressive disorder. The DoC is the score of feature importance used for feature ranking. The algorithm involves four stages: feature ranking, subset generation, subset evaluation, and DoC analysis. The performance of DoC is evaluated on the Duke University Multi-site Imaging Research in the Analysis of Depression sMRI dataset. The dataset consists of 115 brain sMRI scans of 88 healthy controls and 27 depressed subjects. Forty-four sMRI volumetric features are used in the evaluation. The DoC score of forty-four features was determined as the accuracy threshold (Acc_Thresh) was varied. The DoC performance was compared with that of four existing FS algorithms. At all defined Acc_Threshs, DoC outperformed the four examined FS algorithms for the average classification score and the maximum classification score. DoC has a good ability to generate reduced-size subsets of important features that could yield high classification accuracy. Based on the DoC score, the most discriminant volumetric features are those from the left-brain region.

Detection of local recurrent prostate cancer after radical prostatectomy in terms of salvage radiotherapy using dynamic contrast enhanced-MRI without endorectal coil

International Nuclear Information System (INIS)

Rischke, Hans Christian; Schäfer, Arnd O; Nestle, Ursula; Volegova-Neher, Natalja; Henne, Karl; Benz, Matthias R; Schultze-Seemann, Wolfgang; Langer, Mathias; Grosu, Anca L

2012-01-01

To evaluate the value of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI) without endorectal coil (EC) in the detection of local recurrent prostate cancer (PC) after radical prostatectomy (RP). Thirty-three patients with recurrent PC underwent DCE-MRI without EC before salvage radiotherapy (RT). At median 15 (mean 16±4.9, range 12–27) months after completion of RT all patients showed complete biochemical response. Additional follow up post RT DCE-MRI scans were available. Prostate specific antigen (PSA) levels at the time of imaging were correlated to the imaging findings. In 22/33 patients (67%) early contrast enhancing nodules were detected in the post-prostatectomy fossa on pre-RT DCE-MRI images. The average pre-RT PSA level of the 22 patients with positive pre-RT DCE-MRI findings was significantly higher (mean, 0.74±0.64 ng/mL) compared to the pre-RT PSA level of the 11 patients with negative pre-RT DCE-MRI (mean, 0.24±0.13 ng/mL) (p<0.001). All post-RT DCE-MRI images showed complete resolution of initial suspicious lesions. A pre-RT PSA cut-off value of ≥0.54 ng/ml readily predicted a positive DCE-MRI finding. This is the first study that shows that DCE-MRI without EC can detect local recurrent PC with an estimated accuracy of 83% at low PSA levels. All false negative DCE-MRI scans were detected using a PSA cut-off of ≥0.54 ng/mL

Preoperative functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS)

DEFF Research Database (Denmark)

Hartwigsen, G.; Siebner, Hartwig R.; Stippich, C.

2010-01-01

Neurosurgical resection of brain lesions aims to maximize excision while minimizing the risk of permanent injury to the surrounding intact brain tissue and resulting neurological deficits. While direct electrical cortical stimulation at the time of surgery allows the precise identification...... of essential cortex, it cannot provide information preoperatively for surgical planning.Brain imaging techniques such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS) are increasingly being used to localize functionally critical cortical......, if the stimulated cortex makes a critical contribution to the brain functions subserving the task. While the relationship between task and functional activation as revealed by fMRI is correlative in nature, the neurodisruptive effect of TMS reflects a causal effect on brain activity.The use of preoperative f...

Detection of local recurrent prostate cancer after radical prostatectomy in terms of salvage radiotherapy using dynamic contrast enhanced-MRI without endorectal coil

Directory of Open Access Journals (Sweden)

Rischke Hans Christian

2012-10-01

Full Text Available Abstract Purpose To evaluate the value of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI without endorectal coil (EC in the detection of local recurrent prostate cancer (PC after radical prostatectomy (RP. Material and methods Thirty-three patients with recurrent PC underwent DCE-MRI without EC before salvage radiotherapy (RT. At median 15 (mean 16±4.9, range 12–27 months after completion of RT all patients showed complete biochemical response. Additional follow up post RT DCE-MRI scans were available. Prostate specific antigen (PSA levels at the time of imaging were correlated to the imaging findings. Results In 22/33 patients (67% early contrast enhancing nodules were detected in the post-prostatectomy fossa on pre-RT DCE-MRI images. The average pre-RT PSA level of the 22 patients with positive pre-RT DCE-MRI findings was significantly higher (mean, 0.74±0.64 ng/mL compared to the pre-RT PSA level of the 11 patients with negative pre-RT DCE-MRI (mean, 0.24±0.13 ng/mL (p Conclusions This is the first study that shows that DCE-MRI without EC can detect local recurrent PC with an estimated accuracy of 83% at low PSA levels. All false negative DCE-MRI scans were detected using a PSA cut-off of ≥0.54 ng/mL.

On the Averaging of Cardiac Diffusion Tensor MRI Data: The Effect of Distance Function Selection

Science.gov (United States)

Giannakidis, Archontis; Melkus, Gerd; Yang, Guang; Gullberg, Grant T.

2016-01-01

Diffusion tensor magnetic resonance imaging (DT-MRI) allows a unique insight into the microstructure of highly-directional tissues. The selection of the most proper distance function for the space of diffusion tensors is crucial in enhancing the clinical application of this imaging modality. Both linear and nonlinear metrics have been proposed in the literature over the years. The debate on the most appropriate DT-MRI distance function is still ongoing. In this paper, we presented a framework to compare the Euclidean, affine-invariant Riemannian and log-Euclidean metrics using actual high-resolution DT-MRI rat heart data. We employed temporal averaging at the diffusion tensor level of three consecutive and identically-acquired DT-MRI datasets from each of five rat hearts as a means to rectify the background noise-induced loss of myocyte directional regularity. This procedure is applied here for the first time in the context of tensor distance function selection. When compared with previous studies that used a different concrete application to juxtapose the various DT-MRI distance functions, this work is unique in that it combined the following: (i) Metrics were judged by quantitative –rather than qualitative– criteria, (ii) the comparison tools were non-biased, (iii) a longitudinal comparison operation was used on a same-voxel basis. The statistical analyses of the comparison showed that the three DT-MRI distance functions tend to provide equivalent results. Hence, we came to the conclusion that the tensor manifold for cardiac DT-MRI studies is a curved space of almost zero curvature. The signal to noise ratio dependence of the operations was investigated through simulations. Finally, the “swelling effect” occurrence following Euclidean averaging was found to be too unimportant to be worth consideration. PMID:27754986

On the averaging of cardiac diffusion tensor MRI data: the effect of distance function selection

Science.gov (United States)

Giannakidis, Archontis; Melkus, Gerd; Yang, Guang; Gullberg, Grant T.

2016-11-01

Diffusion tensor magnetic resonance imaging (DT-MRI) allows a unique insight into the microstructure of highly-directional tissues. The selection of the most proper distance function for the space of diffusion tensors is crucial in enhancing the clinical application of this imaging modality. Both linear and nonlinear metrics have been proposed in the literature over the years. The debate on the most appropriate DT-MRI distance function is still ongoing. In this paper, we presented a framework to compare the Euclidean, affine-invariant Riemannian and log-Euclidean metrics using actual high-resolution DT-MRI rat heart data. We employed temporal averaging at the diffusion tensor level of three consecutive and identically-acquired DT-MRI datasets from each of five rat hearts as a means to rectify the background noise-induced loss of myocyte directional regularity. This procedure is applied here for the first time in the context of tensor distance function selection. When compared with previous studies that used a different concrete application to juxtapose the various DT-MRI distance functions, this work is unique in that it combined the following: (i) metrics were judged by quantitative—rather than qualitative—criteria, (ii) the comparison tools were non-biased, (iii) a longitudinal comparison operation was used on a same-voxel basis. The statistical analyses of the comparison showed that the three DT-MRI distance functions tend to provide equivalent results. Hence, we came to the conclusion that the tensor manifold for cardiac DT-MRI studies is a curved space of almost zero curvature. The signal to noise ratio dependence of the operations was investigated through simulations. Finally, the ‘swelling effect’ occurrence following Euclidean averaging was found to be too unimportant to be worth consideration.

Comparison of abdominal MRI with diffusion-weighted imaging to {sup 68}Ga-DOTATATE PET/CT in detection of neuroendocrine tumors of the pancreas

Energy Technology Data Exchange (ETDEWEB)

Schmid-Tannwald, Christine; Schmid-Tannwald, Christoph M.; Neumann, Ralph; Nikolaou, Konstantin; Schramm, Nicolai; Reiser, Maximilian F.; Rist, Carsten [Ludwig Maximilians University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Morelli, John N. [Scott and White Hospital Temple, Department of Radiology, Temple, TX (United States); Haug, Alexander R.; Jansen, Nathalie [Ludwig Maximilians University Hospital Munich, Department of Nuclear Medicine, Munich (Germany)

2013-06-15

The aim of the study was to evaluate contrast-enhanced MRI, diffusion-weighted MRI (DW MRI), and {sup 68}Ga-DOTATATE positron emission tomography (PET)/CT in the detection of intermediate to well-differentiated neuroendocrine tumors (NET) of the pancreas. Eighteen patients with pathologically proven pancreatic NET who underwent MRI including DW MRI and PET/CT within 6 weeks of each other were included in this retrospective study. Two radiologists evaluated T2-weighted (T2w), T2w + DW MRI, T2w + contrast-enhanced T1-weighted (CE T1w) MR images, and PET/CT for NET detection. The sensitivity and level of diagnostic confidence were compared among modalities using McNemar's test and a Wilcoxon signed rank test. Apparent diffusion coefficients (ADC) of pancreatic NETs and normal pancreatic tissue were compared with Student's t test. Of the NETs, 8/23 (34.8 %) and 9/23 (39.1 %) were detected on T2w images by observers 1 and 2, respectively. Detection rates improved significantly by combining T2w images with DW MRI (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05) or CE T1w images (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05). Detection rates of pancreatic NET with PET/CT (both observers: 23/23 = 100 %) were statistically significantly higher than with MRI (p < 0.05). The mean ADC value of NET (1.02 {+-} 0.26 x 10{sup -3} mm{sup 2}/s) was statistically significantly lower than that of normal pancreatic tissue (1.48 {+-} 0.39 x 10{sup -3} mm{sup 2}/s). DW MRI is a valuable adjunct to T2w imaging and comparable to CE T1w imaging in pancreatic NET detection, quantitatively differentiating between NET and normal pancreatic tissue with ADC measurements. {sup 68}Ga-DOTATATE PET/CT is more sensitive than MRI in the detection of pancreatic NET. (orig.)

High frame rate retrospectively triggered Cine MRI for assessment of murine diastolic function

NARCIS (Netherlands)

Coolen, Bram F.; Abdurrachim, Desiree; Motaal, Abdallah G.; Nicolay, Klaas; Prompers, Jeanine J.; Strijkers, Gustav J.

2013-01-01

To assess left ventricular (LV) diastolic function in mice with Cine MRI, a high frame rate (>60 frames per cardiac cycle) is required. For conventional electrocardiography-triggered Cine MRI, the frame rate is inversely proportional to the pulse repetition time (TR). However, TR cannot be lowered

TH-CD-202-09: Free-Breathing Proton MRI Functional Lung Avoidance Maps to Guide Radiation Therapy

International Nuclear Information System (INIS)

Capaldi, D; Sheikh, K; Parraga, G; Hoover, D; Yaremko, B; Palma, D

2016-01-01

Purpose: Pulmonary functional MRI using inhaled gas contrast agents was previously investigated as a way to identify well-functioning lung in patients with NSCLC who are clinical candidates for radiotherapy. Hyperpolarized noble-gas ( 3 He and 129 Xe) MRI has also been optimized to measure functional lung information, but for a number of reasons, the clinical translation of this approach to guide radiotherapy planning has been limited. As an alternative, free-breathing pulmonary 1H MRI using clinically available MRI systems and pulse sequences provides a non-contrast-enhanced method to generate both ventilation and perfusion maps. Free-breathing 1 H MRI exploits non-rigid registration and Fourier decomposition of MRI signal intensity differences (Bauman et al., MRM, 2009) that may be generated during normal tidal breathing. Here, our objective was to generate free-breathing 1 H MRI ventilation and lung function avoidance maps in patients with NSCLC as a way to guide radiation therapy planning. Methods: Stage IIIA/IIIB NSCLC patients (n=8, 68±9yr) provided written informed consent to a randomized controlled clinical trial ( https://clinicaltrials.gov/ct2/show/NCT02002052 ) that aimed to compare outcomes related to image-guided versus conventional radiation therapy planning. Hyperpolarized 3 He/ 129 Xe and dynamic free tidal-breathing 1 H MRI were acquired as previously described (Capaldi et al., Acad Radiol, 2015). Non-rigid registration was performed using the modality-independent-neighbourhood-descriptor (MIND) deformable approach (Heinrich et al., Med Image Anal, 2012). Ventilation-defect-percent ( 3 He:VDP He , 129 Xe:VDP Xe , Free-breathing- 1 H:VDP FB ) and the corresponding ventilation maps were compared using Pearson correlation coefficients (r) and the Dice similarity coefficient (DSC). Results: VDP FB was significantly related to VDP He (r=.71; p=.04) and VDP Xe (r=.80; p=.01) and there were also strong spatial relationships (DSC He /DSC Xe =89±3%/77±11

Probing the brain with molecular fMRI.

Science.gov (United States)

Ghosh, Souparno; Harvey, Peter; Simon, Jacob C; Jasanoff, Alan

2018-04-09

One of the greatest challenges of modern neuroscience is to incorporate our growing knowledge of molecular and cellular-scale physiology into integrated, organismic-scale models of brain function in behavior and cognition. Molecular-level functional magnetic resonance imaging (molecular fMRI) is a new technology that can help bridge these scales by mapping defined microscopic phenomena over large, optically inaccessible regions of the living brain. In this review, we explain how MRI-detectable imaging probes can be used to sensitize noninvasive imaging to mechanistically significant components of neural processing. We discuss how a combination of innovative probe design, advanced imaging methods, and strategies for brain delivery can make molecular fMRI an increasingly successful approach for spatiotemporally resolved studies of diverse neural phenomena, perhaps eventually in people. Copyright © 2018 Elsevier Ltd. All rights reserved.

Simultaneous fMRI-PET of the opioidergic pain system in human brain

DEFF Research Database (Denmark)

Wey, Hsiao-Ying; Catana, Ciprian; Hooker, Jacob M

2014-01-01

distinct components of the blood oxygenation level dependent (BOLD) fMRI signal has not yet been shown. We obtained sixteen fMRI-PET data sets from eight healthy volunteers. Each subject participated in randomized order in a pain scan and a control (nonpainful pressure) scan on the same day. Dynamic PET......MRI and PET provide complementary information for studying brain function. While the potential use of simultaneous MRI/PET for clinical diagnostic and disease staging has been demonstrated recently; the biological relevance of concurrent functional MRI-PET brain imaging to dissect neurochemically...... data were acquired with an opioid radioligand, [(11)C]diprenorphine, to detect endogenous opioid releases in response to pain. BOLD fMRI data were collected at the same time to capture hemodynamic responses. In this simultaneous human fMRI-PET imaging study, we show co-localized responses in thalamus...

State-space model with deep learning for functional dynamics estimation in resting-state fMRI.

Science.gov (United States)

Suk, Heung-Il; Wee, Chong-Yaw; Lee, Seong-Whan; Shen, Dinggang

2016-04-01

Studies on resting-state functional Magnetic Resonance Imaging (rs-fMRI) have shown that different brain regions still actively interact with each other while a subject is at rest, and such functional interaction is not stationary but changes over time. In terms of a large-scale brain network, in this paper, we focus on time-varying patterns of functional networks, i.e., functional dynamics, inherent in rs-fMRI, which is one of the emerging issues along with the network modelling. Specifically, we propose a novel methodological architecture that combines deep learning and state-space modelling, and apply it to rs-fMRI based Mild Cognitive Impairment (MCI) diagnosis. We first devise a Deep Auto-Encoder (DAE) to discover hierarchical non-linear functional relations among regions, by which we transform the regional features into an embedding space, whose bases are complex functional networks. Given the embedded functional features, we then use a Hidden Markov Model (HMM) to estimate dynamic characteristics of functional networks inherent in rs-fMRI via internal states, which are unobservable but can be inferred from observations statistically. By building a generative model with an HMM, we estimate the likelihood of the input features of rs-fMRI as belonging to the corresponding status, i.e., MCI or normal healthy control, based on which we identify the clinical label of a testing subject. In order to validate the effectiveness of the proposed method, we performed experiments on two different datasets and compared with state-of-the-art methods in the literature. We also analyzed the functional networks learned by DAE, estimated the functional connectivities by decoding hidden states in HMM, and investigated the estimated functional connectivities by means of a graph-theoretic approach. Copyright © 2016 Elsevier Inc. All rights reserved.

Predictive values of BI-RADS{sup ®} magnetic resonance imaging (MRI) in the detection of breast ductal carcinoma in situ (DCIS)

Energy Technology Data Exchange (ETDEWEB)

Badan, Gustavo Machado, E-mail: gustavobadan@hotmail.com [Breast Imaging Service of Radiology Depatment—Irmandade da Santa Casa de Misericórdia de São Paulo, São Paulo, SP (Brazil); Piato, Sebastião [Mastology Division—Gynecology and Obstetrics Department (Brazil); Roveda, Décio; Faria Castro Fleury, Eduardo de [Breast Imaging Service of Radiology Depatment—Irmandade da Santa Casa de Misericórdia de São Paulo, São Paulo, SP (Brazil)

2016-10-15

Purpose: The purpose of this study was to evaluate BI-RADS indicators in the detection of DCIS by MRI. Materials and methods: Prospective observational study that started in 2014 and lasted 24 months. A total of 110 consecutive patients were evaluated, who presented with suspicious or highly suspicious microcalcifications on screening mammography (BI-RADS categories 4 and 5) and underwent stereotactic-guided breast biopsy, having had an MRI scan performed prior to biopsy. Results: Altogether, 38 cases were characterized as positive for malignancy, of which 25 were DCIS and 13 were invasive ductal carcinoma cases. MRI had a sensitivity of 96%; specificity of 75.67%; positive predictive value (PPV) for DCIS detection of 57.14%; negative predictive value (NPV) in the detection of DCIS of 98.24%; and an accuracy of 80.80%. Conclusion: BI-RADS as a tool for the detection of DCIS by MRI is a powerful instrument whose sensitivity was higher when compared to that observed for mammography in the literature. Likewise, the PPV obtained by MRI was higher than that observed in the present study for mammography, and the high NPV obtained on MRI scans can provide early evidence to discourage breast biopsy in selected cases.

Detection of electroporation-induced membrane permeabilization states in the brain using diffusion-weighted MRI

DEFF Research Database (Denmark)

Mahmood, Faisal; Hansen, Rasmus H; Agerholm-Larsen, Birgit

2015-01-01

BACKGROUND: Tissue permeabilization by electroporation (EP) is a promising technique to treat certain cancers. Non-invasive methods for verification of induced permeabilization are important, especially in deep-seated cancers. In this study we evaluated diffusion-weighted magnetic resonance imaging...... (NP), transient membrane permeabilization (TMP), and permanent membrane permeabilization (PMP), respectively. DW-MRI was acquired 5 minutes, 2 hours, 24 hours and 48 hours after EP. Histology was performed for validation of the permeabilization states. Tissue content of water, Na+, K+, Ca2...... minutes after EP, compared to NP. Kurtosis was also significantly higher at 24 hours (pstates, supporting the DW-MRI findings. We conclude that DW-MRI is capable of detecting EP...

Detection of hepatocellular carcinoma by Gd-EOB-DTPA-enhanced liver MRI: Comparison with triple phase 64 detector row helical CT

International Nuclear Information System (INIS)

Akai, Hiroyuki; Kiryu, Shigeru; Matsuda, Izuru; Satou, Jirou; Takao, Hidemasa; Tajima, Taku; Watanabe, Yasushi; Imamura, Hiroshi; Kokudo, Norihiro; Akahane, Masaaki; Ohtomo, Kuni

2011-01-01

Purpose: To compare the diagnostic performance of Gd-EOB-DTPA-enhanced MRI with that of triple phase 64-MDCT in the detection of hepatocellular carcinoma (HCC). Patients and methods: Thirty-four patients with 52 surgically proven lesions underwent Gd-EOB-DTPA-enhanced MRI and triple phase 64-MDCT. Two observers independently evaluated MR and CT imaging on a lesion-by-lesion basis. Sensitivity, positive and negative predictive values and reproducibility were evaluated. The diagnostic accuracy of each modality was assessed with alternative-free response receiver operating characteristic (ROC) analysis. Results: Both observers showed higher sensitivity in detecting lesions with MRI compared to CT, however, only the difference between the two imaging techniques for observer 2 was significant (P = 0.034). For lesions 1 cm or smaller, MRI and CT showed equal sensitivity (both 62.5%) with one observer, and MRI proved superior to CT with the other observer (MRI 75% vs. CT 56.3%), but the latter difference was not significant (P = 0.083). The difference in positive and negative predictive value between the two imaging techniques for each observer was not significant (P > 0.05). The areas under the ROC curve for each observer were 0.843 and 0.861 for MRI vs. 0.800 and 0.833 for CT and the differences were not significant. Reproducibility was higher using MRI for both observers, but the result was not significant (MRI 32/33 vs. CT 29/33, P = 0.083). Conclusion: Gd-EOB-DTPA-enhanced MRI tended to show higher diagnostic accuracy, sensitivity and reproducibility compared to triple phase 64-MDCT in the detection of hepatocellular carcinoma, however statistical significance was not achieved.

Detection of white matter lesion regions in MRI using SLIC0 and convolutional neural network.

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Diniz, Pedro Henrique Bandeira; Valente, Thales Levi Azevedo; Diniz, João Otávio Bandeira; Silva, Aristófanes Corrêa; Gattass, Marcelo; Ventura, Nina; Muniz, Bernardo Carvalho; Gasparetto, Emerson Leandro

2018-04-19

White matter lesions are non-static brain lesions that have a prevalence rate up to 98% in the elderly population. Because they may be associated with several brain diseases, it is important that they are detected as soon as possible. Magnetic Resonance Imaging (MRI) provides three-dimensional data with the possibility to detect and emphasize contrast differences in soft tissues, providing rich information about the human soft tissue anatomy. However, the amount of data provided for these images is far too much for manual analysis/interpretation, representing a difficult and time-consuming task for specialists. This work presents a computational methodology capable of detecting regions of white matter lesions of the brain in MRI of FLAIR modality. The techniques highlighted in this methodology are SLIC0 clustering for candidate segmentation and convolutional neural networks for candidate classification. The methodology proposed here consists of four steps: (1) images acquisition, (2) images preprocessing, (3) candidates segmentation and (4) candidates classification. The methodology was applied on 91 magnetic resonance images provided by DASA, and achieved an accuracy of 98.73%, specificity of 98.77% and sensitivity of 78.79% with 0.005 of false positives, without any false positives reduction technique, in detection of white matter lesion regions. It is demonstrated the feasibility of the analysis of brain MRI using SLIC0 and convolutional neural network techniques to achieve success in detection of white matter lesions regions. Copyright © 2018. Published by Elsevier B.V.

Functional versus Nonfunctional Rehabilitation in Chronic Ischemic Stroke: Evidences from a Randomized Functional MRI Study

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Maristela C. X. Pelicioni

2016-01-01

Full Text Available Motor rehabilitation of stroke survivors may include functional and/or nonfunctional strategy. The present study aimed to compare the effect of these two rehabilitation strategies by means of clinical scales and functional Magnetic Resonance Imaging (fMRI. Twelve hemiparetic chronic stroke patients were selected. Patients were randomly assigned a nonfunctional (NFS or functional (FS rehabilitation scheme. Clinical scales (Fugl-Meyer, ARA test, and modified Barthel and fMRI were applied at four moments: before rehabilitation (P1 and immediately after (P2, 1 month after (P3, and three months after (P4 the end of rehabilitation. The NFS group improved significantly and exclusively their Fugl-Meyer scores at P2, P3, and P4, when compared to P1. On the other hand, the FS group increased significantly in Fugl-Meyer at P2, when compared to P1, and also in their ARA and Barthel scores. fMRI inspection at the individual level revealed that both rehabilitation schemes most often led to decreased activation sparseness, decreased activity of contralesional M1, increased asymmetry of M1 activity to the ipsilesional side, decreased perilesional activity, and decreased SMA activity. Increased M1 asymmetry with rehabilitation was also confirmed by Lateralization Indexes. Our clinical analysis revealed subtle differences between FS and NFS.

MRI: A method to detect minor brain damage following coronary bypass surgery

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Vik, A.; Brubakk, A.O. (Trondheim Univ. (Norway). Dept. of Biomedical Engineering); Rinck, P.A. (Trondheim Univ. (Norway). MR Center); Sande, E.; Levang, O.W. (Trondheim Univ. Hospital (Norway). Dept. of Surgery); Sellevold, O. (Trondheim Univ. Hospital (Norway). Dept. of Anaesthesiology)

1991-10-01

In order to assess the occurrence of minor focal brain lesions after coronary bypass surgery, magnetic resonance imaging (MRI) was used. Nine male patients (age 42-63) with angina pectoris were investigated at 0.5 Tesla. The investigation was performed one to seven weeks prior to the operation and one month after the operation. Before surgery, the images demonstrated more than five high intensity spots in the white matter of the brain in all but two patients. No additional spots were found after operation. This pilot study indicates that it might be difficult to use MRI to detect minor parenchymal lesions after cardiopulmonary bypass surgery. (orig.).

Multimodal functional network connectivity: an EEG-fMRI fusion in network space.

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Xu Lei

Full Text Available EEG and fMRI recordings measure the functional activity of multiple coherent networks distributed in the cerebral cortex. Identifying network interaction from the complementary neuroelectric and hemodynamic signals may help to explain the complex relationships between different brain regions. In this paper, multimodal functional network connectivity (mFNC is proposed for the fusion of EEG and fMRI in network space. First, functional networks (FNs are extracted using spatial independent component analysis (ICA in each modality separately. Then the interactions among FNs in each modality are explored by Granger causality analysis (GCA. Finally, fMRI FNs are matched to EEG FNs in the spatial domain using network-based source imaging (NESOI. Investigations of both synthetic and real data demonstrate that mFNC has the potential to reveal the underlying neural networks of each modality separately and in their combination. With mFNC, comprehensive relationships among FNs might be unveiled for the deep exploration of neural activities and metabolic responses in a specific task or neurological state.

Unenhanced breast MRI (STIR, T2-weighted TSE, DWIBS): An accurate and alternative strategy for detecting and differentiating breast lesions.

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Telegrafo, Michele; Rella, Leonarda; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe; Moschetta, Marco

2015-10-01

To assess the role of STIR, T2-weighted TSE and DWIBS sequences for detecting and characterizing breast lesions and to compare unenhanced (UE)-MRI results with contrast-enhanced (CE)-MRI and histological findings, having the latter as the reference standard. Two hundred eighty consecutive patients (age range, 27-73 years; mean age±standard deviation (SD), 48.8±9.8years) underwent MR examination with a diagnostic protocol including STIR, T2-weighted TSE, THRIVE and DWIBS sequences. Two radiologists blinded to both dynamic sequences and histological findings evaluated in consensus STIR, T2-weighted TSE and DWIBS sequences and after two weeks CE-MRI images searching for breast lesions. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy for UE-MRI and CE-MRI were calculated. UE-MRI results were also compared with CE- MRI. UE-MRI sequences obtained sensitivity, specificity, diagnostic accuracy, PPV and NPV values of 94%, 79%, 86%, 79% and 94%, respectively. CE-MRI sequences obtained sensitivity, specificity, diagnostic accuracy, PPV and NPV values of 98%, 83%, 90%, 84% and 98%, respectively. No statistically significant difference between UE-MRI and CE-MRI was found. Breast UE-MRI could represent an accurate diagnostic tool and a valid alternative to CE-MRI for evaluating breast lesions. STIR and DWIBS sequences allow to detect breast lesions while T2-weighted TSE sequences and ADC values could be useful for lesion characterization. Copyright © 2015 Elsevier Inc. All rights reserved.

Functional magnetic resonance imaging (fMRI) of motor deficits in schizophrenia

International Nuclear Information System (INIS)

Wenz, F.; Floemer, F.; Kaick, G. van

1995-01-01

The purpose of this study was to investigate differences in the cerebral activation pattern in ten schizophrenic patients and ten healthy volunteers using functional MRI. fMRI was performed using a modified FLASH sequence (TR/TE/α=100/60/40 ) and a conventional 1.5 T MR scanner. Colorcoded statistical parametric maps based on Student's t-test were calculated. Activation strength was quantified using a 5x6 grid overlay. The volunteers showed a higher activation strength during left hand movement compared to right hand movement. This lateralization effect was reversed in patients who showed overall reduced activation strength. Disturbed interhemispheric balance in schizophrenic patients during motor task performance can be demonstrated using fMRI. (orig.) [de

Emerging role of functional brain MRI in low-grade glioma surgery

DEFF Research Database (Denmark)

Friismose, Ancuta; Traise, Peter; Markovic, Ljubo

Learning objectives 1. To describe the use of functional MRI (fMRI) in cranial surgery planning for patients with low-grade gliomas (LGG). 2. To show the increasing importance of fMRI in the clinical setting. Background LGG include brain tumors classified by the World Health Organization as grade I...... be used to map eloquent cortex areas, thus minimizing postoperative deficits and improving surgical performance. Findings and procedure details Patients diagnosed with low-grade gliomas located in eloquent brain areas undergo fMRI prior to surgery. The exams are performed on a 3T MR system (Achieva TX....... Language comprehension and visual tasks can be added to visualize Wernicke’s area or the visual cortex. Diffusion tensor imaging (DTI) is used to map nerve tract course relative to the tumour. Conclusion FMRI has proven its clinical utility in locating eloquent brain areas with relation to tumor site...

Prostate cancer detection using multiparametric 3 – tesla MRI and fusion biopsy: preliminary results

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Thais Caldara Mussi

Full Text Available ABSTRACT Objective: To evaluate the diagnostic efficacy of transrectal ultrasonography (US biopsy with imaging fusion using multiparametric (mp magnetic resonance imaging (MRI in patients with suspicion of prostate cancer (PCa, with an emphasis on clinically significant tumors according to histological criteria. Materials and Methods: A total of 189 consecutive US/MRI fusion biopsies were performed obtaining systematic and guided samples of suspicious areas on mpMRI using a 3 Tesla magnet without endorectal coil. Clinical significance for prostate cancer was established based on Epstein criteria. Results: In our casuistic, the average Gleason score was 7 and the average PSA was 5.0ng/mL. Of the 189 patients that received US/MRI biopsies, 110 (58.2% were positive for PCa. Of those cases, 88 (80% were clinically significant, accounting for 46.6% of all patients. We divided the MRI findings into 5 Likert scales of probability of having clinically significant PCa. The positivity of US/MRI biopsy for clinically significant PCa was 0%, 17.6% 23.5%, 53.4% and 84.4% for Likert scores 1, 2, 3, 4 and 5, respectively. There was a statistically significant difference in terms of biopsy results between different levels of suspicion on mpMRI and also when biopsy results were divided into groups of clinically non-significant versus clinically significant between different levels of suspicion on mpMRI (p-value <0.05 in both analyzes. Conclusion: We found that there is a significant difference in cancer detection using US/MRI fusion biopsy between low-probability and intermediate/high probability Likert scores using mpMRI.

Timed function tests, motor function measure, and quantitative thigh muscle MRI in ambulant children with Duchenne muscular dystrophy: A cross-sectional analysis.

Science.gov (United States)

Schmidt, Simone; Hafner, Patricia; Klein, Andrea; Rubino-Nacht, Daniela; Gocheva, Vanya; Schroeder, Jonas; Naduvilekoot Devasia, Arjith; Zuesli, Stephanie; Bernert, Guenther; Laugel, Vincent; Bloetzer, Clemens; Steinlin, Maja; Capone, Andrea; Gloor, Monika; Tobler, Patrick; Haas, Tanja; Bieri, Oliver; Zumbrunn, Thomas; Fischer, Dirk; Bonati, Ulrike

2018-01-01

The development of new therapeutic agents for the treatment of Duchenne muscular dystrophy has put a focus on defining outcome measures most sensitive to capture treatment effects. This cross-sectional analysis investigates the relation between validated clinical assessments such as the 6-minute walk test, motor function measure and quantitative muscle MRI of thigh muscles in ambulant Duchenne muscular dystrophy patients, aged 6.5 to 10.8 years (mean 8.2, SD 1.1). Quantitative muscle MRI included the mean fat fraction using a 2-point Dixon technique, and transverse relaxation time (T2) measurements. All clinical assessments were highly significantly inter-correlated with p muscle MRI values significantly correlated with all clinical assessments with the extensors showing the strongest correlation. In contrast to the clinical assessments, quantitative muscle MRI values were highly significantly correlated with age. In conclusion, the motor function measure and timed function tests measure disease severity in a highly comparable fashion and all tests correlated with quantitative muscle MRI values quantifying fatty muscle degeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of hippocampal function, volume and connectivity on posterior cingulate cortex functioning during episodic memory fMRI in mild cognitive impairment.

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Papma, Janne M; Smits, Marion; de Groot, Marius; Mattace Raso, Francesco U; van der Lugt, Aad; Vrooman, Henri A; Niessen, Wiro J; Koudstaal, Peter J; van Swieten, John C; van der Veen, Frederik M; Prins, Niels D

2017-09-01

Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer's disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI). MCI patients (n = 27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus. We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors. Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI. • PCC functioning during episodic memory relates to hippocampal functioning in MCI. • PCC functioning during episodic memory does not relate to hippocampal structure in MCI. • Functional network changes are an important predictor of PCC functioning in MCI.

Quantitative estimation of renal function with dynamic contrast-enhanced MRI using a modified two-compartment model.

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Bin Chen

Full Text Available To establish a simple two-compartment model for glomerular filtration rate (GFR and renal plasma flow (RPF estimations by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI.A total of eight New Zealand white rabbits were included in DCE-MRI. The two-compartment model was modified with the impulse residue function in this study. First, the reliability of GFR measurement of the proposed model was compared with other published models in Monte Carlo simulation at different noise levels. Then, functional parameters were estimated in six healthy rabbits to test the feasibility of the new model. Moreover, in order to investigate its validity of GFR estimation, two rabbits underwent acute ischemia surgical procedure in unilateral kidney before DCE-MRI, and pixel-wise measurements were implemented to detect the cortical GFR alterations between normal and abnormal kidneys.The lowest variability of GFR and RPF measurements were found in the proposed model in the comparison. Mean GFR was 3.03±1.1 ml/min and mean RPF was 2.64±0.5 ml/g/min in normal animals, which were in good agreement with the published values. Moreover, large GFR decline was found in dysfunction kidneys comparing to the contralateral control group.Results in our study demonstrate that measurement of renal kinetic parameters based on the proposed model is feasible and it has the ability to discriminate GFR changes in healthy and diseased kidneys.

The search for neuroimaging biomarkers of Alzheimer's disease with advanced MRI techniques

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Li, Tie-Qiang (Karolinska Huddinge - Medical Physics, Stockholm (Sweden)), email: tieqiang.li@karolinska.se; Wahlund, Lars-Olof (Dept. of Neurobiology, Care Sciences and Society, Karolinska Institute, Stockholm (Sweden))

2011-02-15

The aim of this review is to examine the recent literature on using advanced magnetic resonance imaging (MRI) techniques for finding neuroimaging biomarkers that are sensitive to the detection of risks for Alzheimer's disease (AD). Since structural MRI techniques, such as brain structural volumetry and voxel based morphometry (VBM), have been widely used for AD studies and extensively reviewed, we will only briefly touch on the topics of volumetry and morphometry. The focus of the current review is about the more recent developments in the search for AD neuroimaging biomarkers with functional MRI (fMRI), resting-state functional connectivity MRI (fcMRI), diffusion tensor imaging (DTI), arterial spin-labeling (ASL), and magnetic resonance spectroscopy (MRS)

Robust Estimation of HDR in fMRI using H-infinity Filters

DEFF Research Database (Denmark)

Puthusserypady, Sadasivan; Jue, R.; Ratnarajah, T.

2010-01-01

Estimation and detection of the hemodynamic response (HDR) are of great importance in functional MRI (fMRI) data analysis. In this paper, we propose the use of three H-infinity adaptive filters (finite memory, exponentially weighted, and timevarying) for accurate estimation and detection of the HDR......-1487]. Performances of the proposed techniques are compared to the conventional t-test method as well as the well-known LMSs and recursive least squares algorithms. Extensive numerical simulations show that the proposed methods result in better HDR estimations and activation detections....

Hybrid ICA-Seed-Based Methods for fMRI Functional Connectivity Assessment: A Feasibility Study

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Robert E. Kelly

2010-01-01

Full Text Available Brain functional connectivity (FC is often assessed from fMRI data using seed-based methods, such as those of detecting temporal correlation between a predefined region (seed and all other regions in the brain; or using multivariate methods, such as independent component analysis (ICA. ICA is a useful data-driven tool, but reproducibility issues complicate group inferences based on FC maps derived with ICA. These reproducibility issues can be circumvented with hybrid methods that use information from ICA-derived spatial maps as seeds to produce seed-based FC maps. We report results from five experiments to demonstrate the potential advantages of hybrid ICA-seed-based FC methods, comparing results from regressing fMRI data against task-related a priori time courses, with “back-reconstruction” from a group ICA, and with five hybrid ICA-seed-based FC methods: ROI-based with (1 single-voxel, (2 few-voxel, and (3 many-voxel seed; and dual-regression-based with (4 single ICA map and (5 multiple ICA map seed.

Comparison of hepatic MDCT, MRI, and DSA to explant pathology for the detection and treatment planning of hepatocellular carcinoma

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Lauren M. Ladd

2016-12-01

Full Text Available Background/Aims The diagnosis and treatment plan for hepatocellular carcinoma (HCC can be made from radiologic imaging. However, lesion detection may vary depending on the imaging modality. This study aims to evaluate the sensitivities of hepatic multidetector computed tomography (MDCT, magnetic resonance imaging (MRI, and digital subtraction angiography (DSA in the detection of HCC and the consequent management impact on potential liver transplant patients. Methods One hundred and sixteen HCC lesions were analyzed in 41 patients who received an orthotopic liver transplant (OLT. All of the patients underwent pretransplantation hepatic DSA, MDCT, and/or MRI. The imaging results were independently reviewed retrospectively in a blinded fashion by two interventional and two abdominal radiologists. The liver explant pathology was used as the gold standard for assessing each imaging modality. Results The sensitivity for overall HCC detection was higher for cross-sectional imaging using MRI (51.5%, 95% confidence interval [CI]=36.2-58.4% and MDCT (49.8%, 95% CI=43.7-55.9% than for DSA (41.7%, 95% CI=36.2-47.3% (P=0.05. The difference in false-positive rate was not statistically significant between MRI (22%, MDCT (29%, and DSA (29% (P=0.67. The sensitivity was significantly higher for detecting right lobe lesions than left lobe lesions for all modalities (MRI: 56.1% vs. 43.1%, MDCT: 55.0% vs. 42.0%, and DSA: 46.9% vs. 33.9%; all P<0.01. The sensitivities of the three imaging modalities were also higher for lesions ≥2 cm vs. <2 cm (MRI: 73.4% vs. 32.7%, MDCT: 66.9% vs. 33.8%, and DSA: 62.2% vs. 24.1%; all P<0.01. The interobserver correlation was rated as very good to excellent. Conclusion The sensitivity for detecting HCC is higher for MRI and MDCT than for DSA, and so cross-sectional imaging modalities should be used to evaluate OLT candidacy.

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

International Nuclear Information System (INIS)

Uematsu, Takayoshi; Kasami, Masako; Watanabe, Junichiro

2011-01-01

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

Functional Topography of Human Corpus Callosum: An fMRI Mapping Study

OpenAIRE

Fabri, Mara; Polonara, Gabriele

2013-01-01

The concept of a topographical map of the corpus callosum (CC) has emerged from human lesion studies and from electrophysiological and anatomical tracing investigations in other mammals. Over the last few years a rising number of researchers have been reporting functional magnetic resonance imaging (fMRI) activation in white matter, particularly the CC. In this study the scope for describing CC topography with fMRI was explored by evoking activation through simple sensory stimulation and moto...

The potential of functional MRI as a biomarker in early Alzheimer’s disease

OpenAIRE

Sperling, Reisa

2011-01-01

Functional magnetic resonance imaging (fMRI) is a relative newcomer in the field of biomarkers for Alzheimer’s disease (AD). fMRI has several potential advantages, particularly for clinical trials, as it is a non-invasive imaging technique that does not require the injection of contrast agent or radiation exposure and thus can be repeated many times during a longitudinal study. fMRI has relatively high spatial and reasonable temporal resolution, and can be acquired in the same session as stru...

Simultaneous detection of landmarks and key-frame in cardiac perfusion MRI using a joint spatial-temporal context model

Science.gov (United States)

Lu, Xiaoguang; Xue, Hui; Jolly, Marie-Pierre; Guetter, Christoph; Kellman, Peter; Hsu, Li-Yueh; Arai, Andrew; Zuehlsdorff, Sven; Littmann, Arne; Georgescu, Bogdan; Guehring, Jens

2011-03-01

Cardiac perfusion magnetic resonance imaging (MRI) has proven clinical significance in diagnosis of heart diseases. However, analysis of perfusion data is time-consuming, where automatic detection of anatomic landmarks and key-frames from perfusion MR sequences is helpful for anchoring structures and functional analysis of the heart, leading toward fully automated perfusion analysis. Learning-based object detection methods have demonstrated their capabilities to handle large variations of the object by exploring a local region, i.e., context. Conventional 2D approaches take into account spatial context only. Temporal signals in perfusion data present a strong cue for anchoring. We propose a joint context model to encode both spatial and temporal evidence. In addition, our spatial context is constructed not only based on the landmark of interest, but also the landmarks that are correlated in the neighboring anatomies. A discriminative model is learned through a probabilistic boosting tree. A marginal space learning strategy is applied to efficiently learn and search in a high dimensional parameter space. A fully automatic system is developed to simultaneously detect anatomic landmarks and key frames in both RV and LV from perfusion sequences. The proposed approach was evaluated on a database of 373 cardiac perfusion MRI sequences from 77 patients. Experimental results of a 4-fold cross validation show superior landmark detection accuracies of the proposed joint spatial-temporal approach to the 2D approach that is based on spatial context only. The key-frame identification results are promising.

Functional neuroimaging of visuospatial working memory tasks enables accurate detection of attention deficit and hyperactivity disorder

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Rubi Hammer

2015-01-01

Full Text Available Finding neurobiological markers for neurodevelopmental disorders, such as attention deficit and hyperactivity disorder (ADHD, is a major objective of clinicians and neuroscientists. We examined if functional Magnetic Resonance Imaging (fMRI data from a few distinct visuospatial working memory (VSWM tasks enables accurately detecting cases with ADHD. We tested 20 boys with ADHD combined type and 20 typically developed (TD boys in four VSWM tasks that differed in feedback availability (feedback, no-feedback and reward size (large, small. We used a multimodal analysis based on brain activity in 16 regions of interest, significantly activated or deactivated in the four VSWM tasks (based on the entire participants' sample. Dimensionality of the data was reduced into 10 principal components that were used as the input variables to a logistic regression classifier. fMRI data from the four VSWM tasks enabled a classification accuracy of 92.5%, with high predicted ADHD probability values for most clinical cases, and low predicted ADHD probabilities for most TDs. This accuracy level was higher than those achieved by using the fMRI data of any single task, or the respective behavioral data. This indicates that task-based fMRI data acquired while participants perform a few distinct VSWM tasks enables improved detection of clinical cases.

Strategies for sensing neurotransmitters with responsive MRI contrast agents.

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Angelovski, Goran; Tóth, Éva

2017-01-23

A great deal of research involving multidisciplinary approaches is currently dedicated to the understanding of brain function. The complexity of physiological processes that underlie neural activity is the greatest hurdle to faster advances. Among imaging techniques, MRI has great potential to enable mapping of neural events with excellent specificity, spatiotemporal resolution and unlimited tissue penetration depth. To this end, molecular imaging approaches using neurotransmitter-sensitive MRI agents have appeared recently to study neuronal activity, along with the first successful in vivo MRI studies. Here, we review the pioneering steps in the development of molecular MRI methods that could allow functional imaging of the brain by sensing the neurotransmitter activity directly. We provide a brief overview of other imaging and analytical methods to detect neurotransmitter activity, and describe the approaches to sense neurotransmitters by means of molecular MRI agents. Based on these initial steps, further progress in probe chemistry and the emergence of innovative imaging methods to directly monitor neurotransmitters can be envisaged.

Integration of fMRI, NIROT and ERP for studies of human brain function.

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Gore, John C; Horovitz, Silvina G; Cannistraci, Christopher J; Skudlarski, Pavel

2006-05-01

Different methods of assessing human brain function possess specific advantages and disadvantages compared to others, but it is believed that combining different approaches will provide greater information than can be obtained from each alone. For example, functional magnetic resonance imaging (fMRI) has good spatial resolution but poor temporal resolution, whereas the converse is true for electrophysiological recordings (event-related potentials or ERPs). In this review of recent work, we highlight a novel approach to combining these modalities in a manner designed to increase information on the origins and locations of the generators of specific ERPs and the relationship between fMRI and ERP signals. Near infrared imaging techniques have also been studied as alternatives to fMRI and can be readily integrated with simultaneous electrophysiological recordings. Each of these modalities may in principle be also used in so-called steady-state acquisitions in which the correlational structure of signals from the brain may be analyzed to provide new insights into brain function.

Hemorrhage detection in MRI brain images using images features

Science.gov (United States)

Moraru, Luminita; Moldovanu, Simona; Bibicu, Dorin; Stratulat (Visan), Mirela

2013-11-01

The abnormalities appear frequently on Magnetic Resonance Images (MRI) of brain in elderly patients presenting either stroke or cognitive impairment. Detection of brain hemorrhage lesions in MRI is an important but very time-consuming task. This research aims to develop a method to extract brain tissue features from T2-weighted MR images of the brain using a selection of the most valuable texture features in order to discriminate between normal and affected areas of the brain. Due to textural similarity between normal and affected areas in brain MR images these operation are very challenging. A trauma may cause microstructural changes, which are not necessarily perceptible by visual inspection, but they could be detected by using a texture analysis. The proposed analysis is developed in five steps: i) in the pre-processing step: the de-noising operation is performed using the Daubechies wavelets; ii) the original images were transformed in image features using the first order descriptors; iii) the regions of interest (ROIs) were cropped from images feature following up the axial symmetry properties with respect to the mid - sagittal plan; iv) the variation in the measurement of features was quantified using the two descriptors of the co-occurrence matrix, namely energy and homogeneity; v) finally, the meaningful of the image features is analyzed by using the t-test method. P-value has been applied to the pair of features in order to measure they efficacy.

Multimodality Functional Imaging in Radiation Therapy Planning: Relationships between Dynamic Contrast-Enhanced MRI, Diffusion-Weighted MRI, and 18F-FDG PET

Directory of Open Access Journals (Sweden)

Moisés Mera Iglesias

2015-01-01

Full Text Available Objectives. Biologically guided radiotherapy needs an understanding of how different functional imaging techniques interact and link together. We analyse three functional imaging techniques that can be useful tools for achieving this objective. Materials and Methods. The three different imaging modalities from one selected patient are ADC maps, DCE-MRI, and 18F-FDG PET/CT, because they are widely used and give a great amount of complementary information. We show the relationship between these three datasets and evaluate them as markers for tumour response or hypoxia marker. Thus, vascularization measured using DCE-MRI parameters can determine tumour hypoxia, and ADC maps can be used for evaluating tumour response. Results. ADC and DCE-MRI include information from 18F-FDG, as glucose metabolism is associated with hypoxia and tumour cell density, although 18F-FDG includes more information about the malignancy of the tumour. The main disadvantage of ADC maps is the distortion, and we used only low distorted regions, and extracellular volume calculated from DCE-MRI can be considered equivalent to ADC in well-vascularized areas. Conclusion. A dataset for achieving the biologically guided radiotherapy must include a tumour density study and a hypoxia marker. This information can be achieved using only MRI data or only PET/CT studies or mixing both datasets.

Comparison of 18F-FDG PET/CT and PET/MRI in patients with multiple myeloma

OpenAIRE

Sachpekidis, Christos; Hillengass, Jens; Goldschmidt, Hartmut; Mosebach, Jennifer; Pan, Leyun; Schlemmer, Heinz-Peter; Haberkorn, Uwe; Dimitrakopoulou-Strauss, Antonia

2015-01-01

PET/MRI represents a promising hybrid imaging modality with several potential clinical applications. Although PET/MRI seems highly attractive in the diagnostic approach of multiple myeloma (MM), its role has not yet been evaluated. The aims of this prospective study are to evaluate the feasibility of 18F-FDG PET/MRI in detection of MM lesions, and to investigate the reproducibility of bone marrow lesions detection and quantitative data of 18F-FDG uptake between the functional (PET) component ...

Combined 18F-Fluciclovine PET/MRI Shows Potential for Detection and Characterization of High-Risk Prostate Cancer.

Science.gov (United States)

Elschot, Mattijs; Selnæs, Kirsten M; Sandsmark, Elise; Krüger-Stokke, Brage; Størkersen, Øystein; Giskeødegård, Guro F; Tessem, May-Britt; Moestue, Siver A; Bertilsson, Helena; Bathen, Tone F

2018-05-01

The objective of this study was to investigate whether quantitative imaging features derived from combined 18 F-fluciclovine PET/multiparametric MRI show potential for detection and characterization of primary prostate cancer. Methods: Twenty-eight patients diagnosed with high-risk prostate cancer underwent simultaneous 18 F-fluciclovine PET/MRI before radical prostatectomy. Volumes of interest (VOIs) for prostate tumors, benign prostatic hyperplasia (BPH) nodules, prostatitis, and healthy tissue were delineated on T2-weighted images, using histology as a reference. Tumor VOIs were marked as high-grade (≥Gleason grade group 3) or not. MRI and PET features were extracted on the voxel and VOI levels. Partial least-squared discriminant analysis (PLS-DA) with double leave-one-patient-out cross-validation was performed to distinguish tumors from benign tissue (BPH, prostatitis, or healthy tissue) and high-grade tumors from other tissue (low-grade tumors or benign tissue). The performance levels of PET, MRI, and combined PET/MRI features were compared using the area under the receiver-operating-characteristic curve (AUC). Results: Voxel and VOI features were extracted from 40 tumor VOIs (26 high-grade), 36 BPH VOIs, 6 prostatitis VOIs, and 37 healthy-tissue VOIs. PET/MRI performed better than MRI and PET alone for distinguishing tumors from benign tissue (AUCs of 87%, 81%, and 83%, respectively, at the voxel level and 96%, 93%, and 93%, respectively, at the VOI level) and high-grade tumors from other tissue (AUCs of 85%, 79%, and 81%, respectively, at the voxel level and 93%, 93%, and 91%, respectively, at the VOI level). T2-weighted MRI, diffusion-weighted MRI, and PET features were the most important for classification. Conclusion: Combined 18 F-fluciclovine PET/multiparametric MRI shows potential for improving detection and characterization of high-risk prostate cancer, in comparison to MRI and PET alone. © 2018 by the Society of Nuclear Medicine and Molecular

Diagnostic performance of CT and MRI on the detection of symptomatic intracranial dural arteriovenous fistula: a meta-analysis with indirect comparison

Energy Technology Data Exchange (ETDEWEB)

Lin, Yen-Heng [National Taiwan University, Institute of Epidemiology and Preventive Medicine, Taipei (China); National Taiwan University Hospital in Taipei and Yuan-Lin Branch, Department of Medical Imaging and Radiology, Hospital and Medical College, Taipei (China); Lin, Hsien-Ho [National Taiwan University, Institute of Epidemiology and Preventive Medicine, Taipei (China); Liu, Hon-Man; Lee, Chung-Wei; Chen, Ya-Fang [National Taiwan University Hospital in Taipei and Yuan-Lin Branch, Department of Medical Imaging and Radiology, Hospital and Medical College, Taipei (China)

2016-08-15

This study aims to review the diagnostic performance of computed tomography (CT) and magnetic resonance imaging (MRI) in symptomatic dural arteriovenous fistula (DAVF). EMBASE, PubMed, and Cochrane Library were searched until April 2015 for studies which compared CT, MRI, or both with angiography for the detection of DAVF. The diagnostic performances of MRI and CT were indirectly compared using modality as a covariate in the analysis. Thirteen studies met our inclusion criteria. MRI had a sensitivity of 0.90 (95 % confidence interval (CI) = 0.83-0.94) and specificity of 0.94 (95 % CI = 0.90-0.96). CT had a sensitivity of 0.80 (95 % CI = 0.62-0.90) and specificity of 0.87 (95 % CI = 0.74-0.94). MRI showed better diagnostic performance than CT (p = 0.02). Contrast medium use and time-resolved MR angiography did not improve MRI diagnostic performance (p = 0.31 and 0.44, respectively). Both CT and MRI had good diagnostic performance. MRI was better than CT on the detection of symptomatic intracranial dural arteriovenous fistula in the indirect comparison. (orig.)

Comparison between air CT and MRI in the detection of small acoustic neurinomas

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Kamei, Tetsuya; Nakashima, Aiko; Seto, Hikaru; Kakishita, Masao

1989-02-01

Air CT proved useful in yielding images of acoustic tumors as an air filling defect in 11 (24%) of 46 patients. Six of the 11 tumors were small ones of less than 1 cm in diameter. Air CT was also able to exclude an intracanalicular tumor in 29 patients (63%). MRI was performed for comparison in eight patients (nine tumors) already diagnosed by air CT as having an acoustic tumor. MRI detected eight (89%) of nine tumors. A false negative result on MRI was obtained only in one intracanalicular tumor (4.3 mm in size). This was considered to be attributable to limitations of spatial resolution including the wide slice thickness. A protocol for radiological investigation and management of patients whose clinical symptoms and/or audiovestibular examination are highly indicative of acoustic tumor is proposed and discussed. (author).

Comparison between air CT and MRI in the detection of small acoustic neurinomas

International Nuclear Information System (INIS)

Kamei, Tetsuya; Nakashima, Aiko; Seto, Hikaru; Kakishita, Masao

1989-01-01

Air CT proved useful in yielding images of acoustic tumors as an air filling defect in 11 (24%) of 46 patients. Six of the 11 tumors were small ones of less than 1 cm in diameter. Air CT was also able to exclude an intracanalicular tumor in 29 patients (63%). MRI was performed for comparison in eight patients (nine tumors) already diagnosed by air CT as having an acoustic tumor. MRI detected eight (89%) of nine tumors. A false negative result on MRI was obtained only in one intracanalicular tumor (4.3 mm in size). This was considered to be attributable to limitations of spatial resolution including the wide slice thickness. A protocol for radiological investigation and management of patients whose clinical symptoms and/or audiovestibular examination are highly indicative of acoustic tumor is proposed and discussed. (author)

Inaudible functional MRI using a truly mute gradient echo sequence

International Nuclear Information System (INIS)

Marcar, V.L.; Girard, F.; Rinkel, Y.; Schneider, J.F.; Martin, E.

2002-01-01

We performed functional MRI experiments using a mute version of a gradient echo sequence on adult volunteers using either a simple visual stimulus (flicker goggles: 4 subjects) or an auditory stimulus (music: 4 subjects). Because the mute sequence delivers fewer images per unit time than a fast echo planar imaging (EPI) sequence, we explored our data using a parametric ANOVA test and a non-parametric Wilcoxon-Mann-Whitney test in addition to performing a cross-correlation analysis. All three methods were in close agreement regarding the location of the BOLD contrast signal change. We demonstrated that, using appropriate statistical analysis, functional MRI using an MR sequence that is acoustically inaudible to the subject is feasible. Furthermore compared with the ''silent'' event-related procedures involving an EPI protocol, our mGE protocol compares favourably with respect to experiment time and the BOLD signal. (orig.)

Low-frequency hippocampal-cortical activity drives brain-wide resting-state functional MRI connectivity.

Science.gov (United States)

Chan, Russell W; Leong, Alex T L; Ho, Leon C; Gao, Patrick P; Wong, Eddie C; Dong, Celia M; Wang, Xunda; He, Jufang; Chan, Ying-Shing; Lim, Lee Wei; Wu, Ed X

2017-08-15

The hippocampus, including the dorsal dentate gyrus (dDG), and cortex engage in bidirectional communication. We propose that low-frequency activity in hippocampal-cortical pathways contributes to brain-wide resting-state connectivity to integrate sensory information. Using optogenetic stimulation and brain-wide fMRI and resting-state fMRI (rsfMRI), we determined the large-scale effects of spatiotemporal-specific downstream propagation of hippocampal activity. Low-frequency (1 Hz), but not high-frequency (40 Hz), stimulation of dDG excitatory neurons evoked robust cortical and subcortical brain-wide fMRI responses. More importantly, it enhanced interhemispheric rsfMRI connectivity in various cortices and hippocampus. Subsequent local field potential recordings revealed an increase in slow oscillations in dorsal hippocampus and visual cortex, interhemispheric visual cortical connectivity, and hippocampal-cortical connectivity. Meanwhile, pharmacological inactivation of dDG neurons decreased interhemispheric rsfMRI connectivity. Functionally, visually evoked fMRI responses in visual regions also increased during and after low-frequency dDG stimulation. Together, our results indicate that low-frequency activity robustly propagates in the dorsal hippocampal-cortical pathway, drives interhemispheric cortical rsfMRI connectivity, and mediates visual processing.

TH-CD-202-09: Free-Breathing Proton MRI Functional Lung Avoidance Maps to Guide Radiation Therapy

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Capaldi, D; Sheikh, K; Parraga, G [Robarts Research Institute, The University of Western Ontario, London, Ontario, CA (United States); Department of Medical Biophysics, The University of Western Ontario, London, Ontario, CA (United States); Hoover, D; Yaremko, B; Palma, D [Department of Medical Biophysics, The University of Western Ontario, London, Ontario, CA (United States); Department of Oncology, The University of Western Ontario, London, Ontario, CA (United States)

2016-06-15

Purpose: Pulmonary functional MRI using inhaled gas contrast agents was previously investigated as a way to identify well-functioning lung in patients with NSCLC who are clinical candidates for radiotherapy. Hyperpolarized noble-gas ({sup 3}He and {sup 129}Xe) MRI has also been optimized to measure functional lung information, but for a number of reasons, the clinical translation of this approach to guide radiotherapy planning has been limited. As an alternative, free-breathing pulmonary 1H MRI using clinically available MRI systems and pulse sequences provides a non-contrast-enhanced method to generate both ventilation and perfusion maps. Free-breathing {sup 1}H MRI exploits non-rigid registration and Fourier decomposition of MRI signal intensity differences (Bauman et al., MRM, 2009) that may be generated during normal tidal breathing. Here, our objective was to generate free-breathing {sup 1}H MRI ventilation and lung function avoidance maps in patients with NSCLC as a way to guide radiation therapy planning. Methods: Stage IIIA/IIIB NSCLC patients (n=8, 68±9yr) provided written informed consent to a randomized controlled clinical trial ( https://clinicaltrials.gov/ct2/show/NCT02002052 ) that aimed to compare outcomes related to image-guided versus conventional radiation therapy planning. Hyperpolarized {sup 3}He/{sup 129}Xe and dynamic free tidal-breathing {sup 1}H MRI were acquired as previously described (Capaldi et al., Acad Radiol, 2015). Non-rigid registration was performed using the modality-independent-neighbourhood-descriptor (MIND) deformable approach (Heinrich et al., Med Image Anal, 2012). Ventilation-defect-percent ({sup 3}He:VDP{sub He}, {sup 129}Xe:VDP{sub Xe}, Free-breathing-{sup 1}H:VDP{sub FB}) and the corresponding ventilation maps were compared using Pearson correlation coefficients (r) and the Dice similarity coefficient (DSC). Results: VDP{sub FB} was significantly related to VDP{sub He} (r=.71; p=.04) and VDP{sub Xe} (r=.80; p=.01) and

The Neural Basis of Typewriting: A Functional MRI Study.

Science.gov (United States)

Higashiyama, Yuichi; Takeda, Katsuhiko; Someya, Yoshiaki; Kuroiwa, Yoshiyuki; Tanaka, Fumiaki

2015-01-01

To investigate the neural substrate of typewriting Japanese words and to detect the difference between the neural substrate of typewriting and handwriting, we conducted a functional magnetic resonance imaging (fMRI) study in 16 healthy volunteers. All subjects were skillful touch typists and performed five tasks: a typing task, a writing task, a reading task, and two control tasks. Three brain regions were activated during both the typing and the writing tasks: the left superior parietal lobule, the left supramarginal gyrus, and the left premotor cortex close to Exner's area. Although typing and writing involved common brain regions, direct comparison between the typing and the writing task revealed greater left posteromedial intraparietal cortex activation in the typing task. In addition, activity in the left premotor cortex was more rostral in the typing task than in the writing task. These findings suggest that, although the brain circuits involved in Japanese typewriting are almost the same as those involved in handwriting, there are brain regions that are specific for typewriting.

The Neural Basis of Typewriting: A Functional MRI Study.

Directory of Open Access Journals (Sweden)

Yuichi Higashiyama

Full Text Available To investigate the neural substrate of typewriting Japanese words and to detect the difference between the neural substrate of typewriting and handwriting, we conducted a functional magnetic resonance imaging (fMRI study in 16 healthy volunteers. All subjects were skillful touch typists and performed five tasks: a typing task, a writing task, a reading task, and two control tasks. Three brain regions were activated during both the typing and the writing tasks: the left superior parietal lobule, the left supramarginal gyrus, and the left premotor cortex close to Exner's area. Although typing and writing involved common brain regions, direct comparison between the typing and the writing task revealed greater left posteromedial intraparietal cortex activation in the typing task. In addition, activity in the left premotor cortex was more rostral in the typing task than in the writing task. These findings suggest that, although the brain circuits involved in Japanese typewriting are almost the same as those involved in handwriting, there are brain regions that are specific for typewriting.

A functional MRI study of deception among offenders with antisocial personality disorders.

Science.gov (United States)

Jiang, W; Liu, H; Liao, J; Ma, X; Rong, P; Tang, Y; Wang, W

2013-08-06

Deceit is a core feature of antisocial personality disorder (ASPD), and the study of deception in ASPD has important implications for identifying the underlying mechanism of ASPD. A great deal of functional neuroimaging literature has described the neural correlates of deception in healthy volunteers, but there have been few imaging studies examining people with ASPD. The neural correlates of lie-telling in ASPD, and which specific brain activities are related to the capacity to lie, are unclear. In this study, 32 offenders who satisfied the Personality Diagnostic Questionaire-4 and PDI-IV (Personality Disorder Interview) criteria for ASPD were divided into three groups based on their capacity for deception, which was evaluated based on the deceitfulness criterion of the PDI-IV ASPD. All offenders underwent functional magnetic resonance imaging (fMRI) while responding to questions in a truthful, inverse, or deceitful manner. We primarily created contrasts in the brain activities between truth-telling and lie-telling, and then computed the Pearson's correlation coefficients between activities contrasts of individual, i.e. BOLD (blood-oxygen-level-dependent) strength during deception minus that during truth-telling, and the capacity for deception. Our results indicated that the bilateral dorsolateral prefrontal cortex extending to the middle frontal gyrus, the left inferior parietal lobule, and the bilateral anterior cingulate gyrus/medial superior frontal gyrus were associated with deception among people with ASPD. As the capacity for deception increased, the contrasted brain activities of the above regions decreased. This study found that truthful and untruthful communications of ASPD subjects can be differentiated in terms of brain BOLD activities, and more importantly, this study is the first to use fMRI to discover that BOLD activities during deception are correlated with the capacity to lie. The latter finding might challenge the diagnostic accuracy of lie

Current stage of fMRI applications in newborns and children during the first year of life

International Nuclear Information System (INIS)

Boecker, H.; Scheef, L.; Jankowski, J.; Zimmermann, N.; Born, M.; Heep, A.

2008-01-01

Currently, a paradigm shift towards expanded early use of cranial MRI in newborns at risk and infants in the first year of life can be observed in neonatology. Beyond clinical MRI applications, there is progressive use of functional MRI (fMRI) in this age group. On the one hand, fMRI allows monitoring of functional developmental processes depending on maturational stage; on the other hand, this technique may provide the basis for early detection of pathophysiological processes as a prerequisite for functionally guided therapeutic interventions. This article provides a comprehensive review of current fMRI applications in neonates and infants during the first year of life and focuses on the associated methodological issues (e.g. signal physiology, sedation, safety aspects). (orig.)

Cardiac MRI in ischemic heart disease

International Nuclear Information System (INIS)

Ishida, Masaki; Kato, Shingo; Sakuma, Hajime

2009-01-01

Considerable progress has been made in cardiac magnetic resonance imaging (MRI). Cine MRI is recognized as the most accurate method for evaluating ventricular function. Late gadolinium-enhanced MRI can clearly delineate subendocardial infarction, and the assessment of transmural extent of infarction on MRI is widely useful for predicting myocardial viability. Stress myocardial perfusion MRI allows for detection of subendocardial myocardial ischemia, and the diagnostic accuracy of stress perfusion MRI is superior to stress perfusion single-photon emission computed tomography in patients with multivessel coronary artery disease (CAD). In recent years, image quality, volume coverage, acquisition speed and arterial contrast of 3-dimensional coronary magnetic resonance angiography (MRA) have been substantially improved with use of steady-state free precession sequences and parallel imaging techniques, permitting the acquisition of high-quality, whole-heart coronary MRA within a reasonably short imaging time. It is now widely recognized that cardiac MRI has tremendous potential for the evaluation of ischemic heart disease. However, cardiac MRI is technically complicated and its use in clinical practice is relatively limited. With further improvements in education and training, as well as standardization of appropriate study protocols, cardiac MRI will play a central role in managing patients with CAD. (author)

Functional and molecular imaging with MRI: potential applications in paediatric radiology

International Nuclear Information System (INIS)

Arthurs, Owen J.; Gallagher, Ferdia A.

2011-01-01

MRI is a very versatile tool for noninvasive imaging and it is particularly attractive as an imaging technique in paediatric patients given the absence of ionizing radiation. Recent advances in the field of MRI have enabled tissue function to be probed noninvasively, and increasingly MRI is being used to assess cellular and molecular processes. For example, dynamic contrast-enhanced MRI has been used to assess tissue vascularity, diffusion-weighted imaging can quantify molecular movements of water in tissue compartments and MR spectroscopy provides a quantitative assessment of metabolite levels. A number of targeted contrast agents have been developed that bind specifically to receptors on the vascular endothelium or cell surface and there are several MR methods for labelling cells and tracking cellular movements. Hyperpolarization techniques have the capability of massively increasing the sensitivity of MRI and these have been used to image tissue pH, successful response to drug treatment as well as imaging the microstructure of the lungs. Although there are many challenges to be overcome before these techniques can be translated into routine paediatric imaging, they could potentially be used to aid diagnosis, predict disease outcome, target biopsies and determine treatment response noninvasively. (orig.)

Functional MRI studies of acupuncture analgesia modulating within the human brain

International Nuclear Information System (INIS)

Hou Jinwen; Huang Weihao; Wang Qing; Feng Jingwei; Pu Yonglin; Gao Jiahong

2002-01-01

Objective: To evaluate the correlation between acupuncture analgesia and specific functional areas of the brain using functional magnetic resonance imaging (fMRI). Methods: Acupuncture stimulation was induced by manipulating acupuncture needle at the acupuncture point, large intestine 4 (LI 4, Hegu) on the right (dominant) hand of 8 healthy subjects. Functional MRI data were obtained from scanning the whole brain. A block-design paradigm was applied. Functional responses were established by students' group t-test analysis. Results: The data sets from 6 of 8 subjects were used in the study. Signal increases and signal decreases elicited by acupuncture stimulating were demonstrated in multiple brain regions. Signal increases in periaqueductal gray matter and ventral posterior nucleus of the left thalamus, and signal decreases in bilateral anterior cingulate cortex and bilateral occipital lobes were considered as the response to the acupuncture modulating within the human brain. Conclusion: The therapeutic effect of acupuncture analgesia was probably produced by the interaction of multiple brain structures of functional connectivity rather than through the activation of a single brain region

The effect of hippocampal function, volume and connectivity on posterior cingulate cortex functioning during episodic memory fMRI in mild cognitive impairment

International Nuclear Information System (INIS)

Papma, Janne M.; Koudstaal, Peter J.; Swieten, John C. van; Smits, Marion; Lugt, Aad van der; Groot, Marius de; Vrooman, Henri A.; Mattace Raso, Francesco U.; Niessen, Wiro J.; Veen, Frederik M. van der; Prins, Niels D.

2017-01-01

Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer's disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI). MCI patients (n = 27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus. We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors. Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI. (orig.)

The effect of hippocampal function, volume and connectivity on posterior cingulate cortex functioning during episodic memory fMRI in mild cognitive impairment

Energy Technology Data Exchange (ETDEWEB)

Papma, Janne M.; Koudstaal, Peter J.; Swieten, John C. van [Erasmus MC - University Medical Center Rotterdam, Department of Neurology, Rotterdam (Netherlands); Smits, Marion; Lugt, Aad van der [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, Rotterdam (Netherlands); Groot, Marius de; Vrooman, Henri A. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, Rotterdam (Netherlands); Erasmus MC - University Medical Center Rotterdam, Department of Medical Informatics, Rotterdam (Netherlands); Mattace Raso, Francesco U. [Erasmus MC - University Medical Center Rotterdam, Department of Geriatrics, Rotterdam (Netherlands); Niessen, Wiro J. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, Rotterdam (Netherlands); Erasmus MC - University Medical Center Rotterdam, Department of Medical Informatics, Rotterdam (Netherlands); Delft University of Technology, Faculty of Applied Sciences, Delft (Netherlands); Veen, Frederik M. van der [Erasmus University Rotterdam, Institute of Psychology, Rotterdam (Netherlands); Prins, Niels D. [VU University Medical Center, Alzheimer Center, Department of Neurology, Amsterdam (Netherlands)

2017-09-15

Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer's disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI). MCI patients (n = 27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus. We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors. Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI. (orig.)

ICN_Atlas: Automated description and quantification of functional MRI activation patterns in the framework of intrinsic connectivity networks.

Science.gov (United States)

Kozák, Lajos R; van Graan, Louis André; Chaudhary, Umair J; Szabó, Ádám György; Lemieux, Louis

2017-12-01

Generally, the interpretation of functional MRI (fMRI) activation maps continues to rely on assessing their relationship to anatomical structures, mostly in a qualitative and often subjective way. Recently, the existence of persistent and stable brain networks of functional nature has been revealed; in particular these so-called intrinsic connectivity networks (ICNs) appear to link patterns of resting state and task-related state connectivity. These networks provide an opportunity of functionally-derived description and interpretation of fMRI maps, that may be especially important in cases where the maps are predominantly task-unrelated, such as studies of spontaneous brain activity e.g. in the case of seizure-related fMRI maps in epilepsy patients or sleep states. Here we present a new toolbox (ICN_Atlas) aimed at facilitating the interpretation of fMRI data in the context of ICN. More specifically, the new methodology was designed to describe fMRI maps in function-oriented, objective and quantitative way using a set of 15 metrics conceived to quantify the degree of 'engagement' of ICNs for any given fMRI-derived statistical map of interest. We demonstrate that the proposed framework provides a highly reliable quantification of fMRI activation maps using a publicly available longitudinal (test-retest) resting-state fMRI dataset. The utility of the ICN_Atlas is also illustrated on a parametric task-modulation fMRI dataset, and on a dataset of a patient who had repeated seizures during resting-state fMRI, confirmed on simultaneously recorded EEG. The proposed ICN_Atlas toolbox is freely available for download at http://icnatlas.com and at http://www.nitrc.org for researchers to use in their fMRI investigations. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Multiparametric prostate MRI for follow-up monitoring after radiation therapy

International Nuclear Information System (INIS)

Weidner, A.M.; Dinter, D.J.; Bohrer, M.; Sertdemir, M.; Hausmann, D.; Wenz, F.; Schoenberg, S.O.

2012-01-01

Radiation therapy is a therapeutic option with curative intent for patients with prostate cancer. Monitoring of prostate-specific antigen (PSA) values is the current standard of care in the follow-up. Imaging is recommended only for symptomatic patients and/or for further therapeutic options. For detection of local recurrence magnetic resonance imaging (MRI) of the prostate is acknowledged as the method of choice. Good results for primary diagnosis were found especially in combination with functional techniques, whereas in recurrent prostate cancer only few studies with heterogeneous study design are available for prostate MRI. Furthermore, changes in different MRI modalities due to radiation therapy have been insufficiently investigated to date. As the initial results were promising prostate MRI and available therapeutic options for detection of local recurrence should be considered in patients with increased PSA. (orig.) [de

Time-delayed contrast-enhanced MRI improves detection of brain metastases and apparent treatment volumes.

Science.gov (United States)

Kushnirsky, Marina; Nguyen, Vinh; Katz, Joel S; Steinklein, Jared; Rosen, Lisa; Warshall, Craig; Schulder, Michael; Knisely, Jonathan P S

2016-02-01

Contrast-enhanced MRI is the preeminent diagnostic test for brain metastasis (BM). Detection of BMs for stereotactic radiosurgery (SRS) planning may improve with a time delay following administration of a high-relaxivity agent for 1.5-T and 3-T imaging systems. Metastasis detection with time-delayed MRI was evaluated in this study. Fifty-three volumetric MRI studies from 38 patients undergoing SRS for BMs were evaluated. All studies used 0.1-mmol/kg gadobenate dimeglumine (MultiHance; Bracco Diagnostics) immediately after injection, followed by 2 more axial T1-weighted sequences after 5-minute intervals (final image acquisition commenced 15 minutes after contrast injection). Two studies were motion limited and excluded. Two hundred eighty-seven BMs were identified. The studies were randomized and examined separately by 3 radiologists, who were blinded to the temporal sequence. Each radiologist recorded the number of BMs detected per scan. A Wilcoxon signed-rank test compared BM numbers between scans. One radiologist determined the scan on which BMs were best defined. All confirmed, visible tumors were contoured using iPlan RT treatment planning software on each of the 3 MRI data sets. A linear mixed model was used to analyze volume changes. The interclass correlations for Scans 1, 2, and 3 were 0.7392, 0.7951, and 0.7290, respectively, demonstrating excellent interrater reliability. At least 1 new lesion was detected in the second scan as compared with the first in 35.3% of subjects (95% CI 22.4%-49.9%). The increase in BM numbers between Scans 1 and 2 ranged from 1 to 10. At least 1 new lesion was detected in the third scan as compared with the second in 21.6% of subjects (95% CI 11.3%-35.3%). The increase in BM numbers between Scans 2 and 3 ranged from 1 to 9. Between Scans 1 and 3, additional tumors were seen on 43.1% of scans (increase ranged from 1 to 14). The median increase in tumor number for all comparisons was 1. There was a significant increase in number

Large-scale functional MRI analysis to accumulate knowledge on brain functions

International Nuclear Information System (INIS)

Schwartz, Yannick

2015-01-01

How can we accumulate knowledge on brain functions? How can we leverage years of research in functional MRI to analyse finer-grained psychological constructs, and build a comprehensive model of the brain? Researchers usually rely on single studies to delineate brain regions recruited by mental processes. They relate their findings to previous works in an informal way by defining regions of interest from the literature. Meta-analysis approaches provide a more principled way to build upon the literature. This thesis investigates three ways to assemble knowledge using activation maps from a large amount of studies. First, we present an approach that uses jointly two similar fMRI experiments, to better condition an analysis from a statistical standpoint. We show that it is a valuable data-driven alternative to traditional regions of interest analyses, but fails to provide a systematic way to relate studies, and thus does not permit to integrate knowledge on a large scale. Because of the difficulty to associate multiple studies, we resort to using a single dataset sampling a large number of stimuli for our second contribution. This method estimates functional networks associated with functional profiles, where the functional networks are interacting brain regions and the functional profiles are a weighted set of cognitive descriptors. This work successfully yields known brain networks and automatically associates meaningful descriptions. Its limitations lie in the unsupervised nature of this method, which is more difficult to validate, and the use of a single dataset. It however brings the notion of cognitive labels, which is central to our last contribution. Our last contribution presents a method that learns functional atlases by combining several datasets. [Henson 2006] shows that forward inference, i.e. the probability of an activation given a cognitive process, is often not sufficient to conclude on the engagement of brain regions for a cognitive process

DW MRI at 3.0 T versus FDG PET/CT for detection of malignant pulmonary tumors.

Science.gov (United States)

Zhang, Jian; Cui, Long-Biao; Tang, Xing; Ren, Xin-Ling; Shi, Jie-Ran; Yang, Hai-Nan; Zhang, Yan; Li, Zhi-Kui; Wu, Chang-Gui; Jian, Wen; Zhao, Feng; Ti, Xin-Yu; Yin, Hong

2014-02-01

Emerging evidence suggests that diffusion-weighted magnetic resonance imaging (DW MRI) could be useful for tumor detection with N and M staging of lung cancer in place of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). DW MRI at 3.0 T and FDG PET/CT were performed before therapy in 113 patients with pulmonary nodules. Mean apparent diffusion coefficient (ADC), maximal standardized uptake value (SUVmax ) and Ki-67 scores were assessed. Quantitatively, specificity and accuracy of ADC (91.7 and 92.9%, respectively) were significantly higher than those of SUVmax (66.7 and 77.9% respectively, p 0.05). Qualitatively, sensitivity, specificity and accuracy of DW MRI (96.1, 83.3 and 92.0%, respectively) were also not significantly different from that of FDG PET/CT (88.3, 83.3 and 86.7%, respectively, p > 0.05). Significant negative correlation was found between Ki-67 score and ADC (r = -0.66, p 0.05). In conclusion, quantitative and qualitative assessments for detection of malignant pulmonary tumors with DW MRI at 3.0 T are superior to those with FDG PET/CT. Furthermore, ADC could predict the malignancy of lung cancer. © 2013 UICC.

MRI detection of soleus muscle injuries in professional football players

Energy Technology Data Exchange (ETDEWEB)

Pezzotta, G.; Querques, G.; Pecorelli, A.; Nani, R.; Sironi, S. [Papa Giovanni XXIII Hospital, University Milano-Bicocca, Department of Radiology, Bergamo (Italy)

2017-11-15

To describe magnetic resonance imaging (MRI) characteristics of soleus muscle injuries in symptomatic professional football players stratified according to both the Munich consensus statement and the British Athletics Muscle Injury Classification (BAMIC), and to investigate the association between specific MRI features and the ''return to play'' (RTP). Professional football players with an episode of acute posterior calf pain and impaired function, subsequent to sports activity, underwent ultrasound followed by MRI examination reviewed by two different radiologists with more than 10 years of experience in the musculoskeletal system. MRI features and RTP outcome were evaluated for all types of injuries. During a 36-month period, a total of 20 professional football players were evaluated. According to the Munich consensus, 11 were type 3A, 8 were type 3B, and 1 was type 4, whereas according to the BAMIC, 11 lesions were considered grade 1, 4 grade 2, 4 grade 3, and 1 grade 4. RTP data were available for all patients (mean 3.3 ± 1.6 weeks). Both the Munich consensus and the BAMIC correlated with RTP (Spearman correlation = 0.982 and p < 0.0001 and 0.886 and p < 0.0001 respectively). Extension of edema was an independent prognostic factor for RTP in two different models of multivariate regression analysis (p = 0.044 model A; p = 0.031 model B). The Munich consensus and BAMIC grading systems are useful tools for defining the patient's prognosis and proper rehabilitation time after injury. The MRI feature that we should carefully look for is the extension of edema, as it seems to significantly affect the RTP. (orig.)

MRI detection of soleus muscle injuries in professional football players

International Nuclear Information System (INIS)

Pezzotta, G.; Querques, G.; Pecorelli, A.; Nani, R.; Sironi, S.

2017-01-01

To describe magnetic resonance imaging (MRI) characteristics of soleus muscle injuries in symptomatic professional football players stratified according to both the Munich consensus statement and the British Athletics Muscle Injury Classification (BAMIC), and to investigate the association between specific MRI features and the ''return to play'' (RTP). Professional football players with an episode of acute posterior calf pain and impaired function, subsequent to sports activity, underwent ultrasound followed by MRI examination reviewed by two different radiologists with more than 10 years of experience in the musculoskeletal system. MRI features and RTP outcome were evaluated for all types of injuries. During a 36-month period, a total of 20 professional football players were evaluated. According to the Munich consensus, 11 were type 3A, 8 were type 3B, and 1 was type 4, whereas according to the BAMIC, 11 lesions were considered grade 1, 4 grade 2, 4 grade 3, and 1 grade 4. RTP data were available for all patients (mean 3.3 ± 1.6 weeks). Both the Munich consensus and the BAMIC correlated with RTP (Spearman correlation = 0.982 and p < 0.0001 and 0.886 and p < 0.0001 respectively). Extension of edema was an independent prognostic factor for RTP in two different models of multivariate regression analysis (p = 0.044 model A; p = 0.031 model B). The Munich consensus and BAMIC grading systems are useful tools for defining the patient's prognosis and proper rehabilitation time after injury. The MRI feature that we should carefully look for is the extension of edema, as it seems to significantly affect the RTP. (orig.)

MRI detection of soleus muscle injuries in professional football players.

Science.gov (United States)

Pezzotta, G; Querques, G; Pecorelli, A; Nani, R; Sironi, S

2017-11-01

To describe magnetic resonance imaging (MRI) characteristics of soleus muscle injuries in symptomatic professional football players stratified according to both the Munich consensus statement and the British Athletics Muscle Injury Classification (BAMIC), and to investigate the association between specific MRI features and the "return to play" (RTP). Professional football players with an episode of acute posterior calf pain and impaired function, subsequent to sports activity, underwent ultrasound followed by MRI examination reviewed by two different radiologists with more than 10 years of experience in the musculoskeletal system. MRI features and RTP outcome were evaluated for all types of injuries. During a 36-month period, a total of 20 professional football players were evaluated. According to the Munich consensus, 11 were type 3A, 8 were type 3B, and 1 was type 4, whereas according to the BAMIC, 11 lesions were considered grade 1, 4 grade 2, 4 grade 3, and 1 grade 4. RTP data were available for all patients (mean 3.3 ± 1.6 weeks). Both the Munich consensus and the BAMIC correlated with RTP (Spearman correlation = 0.982 and p < 0.0001 and 0.886 and p < 0.0001 respectively). Extension of edema was an independent prognostic factor for RTP in two different models of multivariate regression analysis (p = 0.044 model A; p = 0.031 model B). The Munich consensus and BAMIC grading systems are useful tools for defining the patient's prognosis and proper rehabilitation time after injury. The MRI feature that we should carefully look for is the extension of edema, as it seems to significantly affect the RTP.

Assessment of language lateralization with functional magnetic resonance imaging (fMRI)

International Nuclear Information System (INIS)

Salagierska-Barwinska, A.; Goraj, B.

2004-01-01

fMRI offers powerful methods to delineate which brain regions are engaged in language processing in the intact brain. Until now hemisphere dominance for language has been usually assessed by means of the intraoperative methods: the Wada test or electrocortical stimulation mapping. Recently functional MRI becomes the valuable method in determining hemisphere dominance for language. fMRI study was proved to be concordant with invasive measures. fMRI was carried out in 30 healthy selected participants (15 females: 10 strongly right-handed and 5 strongly left-handed; 15 males: 10 strongly right-handed and 5 strongly left-handed). The subject's handedness was assessed by standardized psychological tests inter alia the 'lateralization inventory'. Two different language tasks were used: a verb generation task and a phonological task. Subjects were scanned,while performing experimental block. The block contained alternately 8 active (language task) and 8 control conditions. Statistical analysis of evoked blood oxygenation level-dependent BOLD) responses, measured with echo planar imagining (1.5 T) were used. During a verb generation task in strongly right or left handed subjects the inferior frontal region was activated on the side opposite to the subject's handedness determined by the psychological test. Our fMRI studies demonstrated no gender effects on brain during these language tasks. Our study suggests that fMRI is a good device for the study of the language organization. The advantage of fMRI is its capacity for exact localization of activated areas. fMRI together with adequate neurolinguistic test could be promising routine preoperative tool in identification hemisphere dominance for language. These results encourage to further investigation for evaluating correlation in patients with brain injuries. (author)

Left atrial dysfunction in type 2 diabetes mellitus: insights from cardiac MRI

Energy Technology Data Exchange (ETDEWEB)

Graca, Bruno; Donato, Paulo; Caseiro-Alves, Filipe [University of Coimbra, Faculty of Medicine, Coimbra (Portugal); Coimbra' s Hospital Centre and University, Medical Imaging Department, Coimbra (Portugal); Joao Ferreira, Maria [University of Coimbra, Faculty of Medicine, Coimbra (Portugal); Coimbra' s Hospital Centre and University, Cardiology Department, Coimbra (Portugal); Gomes, Leonor [University of Coimbra, Faculty of Medicine, Coimbra (Portugal); Coimbra' s Hospital Centre and University, Endocrinology Department, Coimbra (Portugal); Castelo-Branco, Miguel [University of Coimbra, Faculty of Medicine, Coimbra (Portugal)

2014-11-15

The left atrium (LA) modulates left ventricular filling through reservoir, conduit and booster pump functions. Only limited data exist on LA involvement in type 2 diabetes mellitus (DM2). This study sought to assess LA function in asymptomatic DM2 with cardiac MRI. We hypothesized that cardiac MRI can detect LA dysfunction in asymptomatic DM2. Forty-five patients with asymptomatic DM2 and 24 normoglycaemic controls were studied. MRI cine imaging was performed to measure LA maximal and minimal volumes. A flow-sensitive phase-contrast gradient-echo sequence was used for flow measurements perpendicular to the orifice of the mitral valve, to quantify active LA stroke volume. LA total, passive and active emptying volumes and fractions were calculated. LA reservoir function, namely LA total ejection fraction, was significantly greater in controls compared to patients with DM2 (62.2 ± 5.2 vs 57.0 ± 7.6 %, P = 0.004). LA passive ejection fraction was also greater in the controls (26.2 ± 9.5 vs 16.1 ± 11.0 %, P < 0.001). Regarding parameters of LA booster pump function, LA active ejection fraction was not significantly different between groups. DM2 was demonstrated to be an independent determinant of LA function. Cardiac MRI enables the detection of LA dysfunction in asymptomatic DM2, characterized by a reduction in LA reservoir and conduit functions. (orig.)