Moshe Graif

High b-Value q-Space Analyzed Diffusion-Weighted MRI: Application to Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) which affects nearly one million people worldwide, leading to a progressive decline of motor and sensory functions, and permanent disability. High b‐value diffusion‐weighted MR images (b of up to 14000 s/mm2) were acquired from the brains of controls and MS patients. These diffusion MR images, in which signal decay is not monoexponential, were analyzed using the q‐space approach that emphasizes the diffusion characteristics of the slow‐diffusing component. From this analysis, displacement and probability maps were constructed. The computed q‐space analyzed MR images that were compared with conventional T1, T2 (fluid attenuated inversion recovery (FLAIR)), and diffusion tensor imaging (DTI) images were found to be sensitive to the pathophysiological state of white matter. The indices used to construct this q‐space analyzed MR maps, provided a pronounced differentiation between normal tissue and tissues classified as MS plaques by the FLAIR images. More importantly, a pronounced differentiation was also observed between tissues classified by the FLAIR MR images as normal‐appearing white matter (NAWM) in the MS brains, which are known to be abnormal, and the respective control tissues. The potential diagnostic capacity of high b‐value diffusion q‐space analyzed MR images is discussed, and experimental data that explains the consequences of using the q‐space approach once the short pulse gradient approximation is violated are presented. Magn Reson Med 47:115–126, 2002.

Normal White Matter Development From Infancy to Adulthood: Comparing Diffusion Tensor and High b Value Diffusion Weighted MR Images

To evaluate the sensitivity of high b value diffusion weight magnetic resonance imaging (DWI) in detecting normal white matter maturation, compare it to conventional diffusion tensor imaging (DTI), and to obtain normative quantitative data using this method.

The septic versus nonseptic inflamed joint: MRI characteristics.

Abstract Objective. To differentiate the MR features of septic versus nonseptic inflamed joints. Design and patients. Thirty patients were referred for MRI with inflamed joints (19 were subsequently found to be septic and 11 nonseptic). At 1.5 T enhanced MRI five groups of signs related to joint space, synovium, cartilage, bone and peri-articular soft tissue respectively were assessed and compared between the septic and nonseptic groups. Results. The prevalence of MRI findings in septic versus nonseptic joints (respectively) was as follows: effusion (79% vs 82%), fluid outpouching (79% vs 73%), fluid heterogeneity (21% vs 27%), synovial thickening (68% vs 55%), synovial periedema (63% vs 55%), synovial enhancement (94% vs 88%), cartilage loss (53% vs 30%), bone erosions (79% vs 38%), bone erosions enhancement (77% vs 43%), bone marrow edema (74% vs 38%), bone marrow enhancement (67% vs 50%), soft tissue edema (63% vs 78%), soft tissue enhancement (67% vs 71%), periosteal edema (11% vs. 10%). The presence of bone erosions appeared to be an indicator for an infected joint (P=0.072); coexistence of bone marrow edema slightly improves the significance (0.068). A similar trend was obtained when combining bone erosions with either synovial thickening, synovial periedema, bone marrow enhancement or soft tissue edema (P=0.075). Conclusions. The combination of bone erosions with marrow edema is highly suggestive for a septic articulation; the additional coexistence of synovial thickening, synovial edema, soft tissue edema or bone marrow enhancement increases the above level of confidence. Similar to conventional radiography, the single sign that appeared to show a significant trend was the presence of bone erosions. However, no single sign or combination could either be considered pathognomonic or exclude the presence of a joint infection.

Diffusion tensor imaging of the median nerve in healthy and carpal tunnel syndrome subjects

To determine if diffusion tensor imaging (DTI) of the median nerve could allow identification of patients with carpal tunnel syndrome (CTS).

High b value q-space-analyzed diffusion MRI in vascular dementia: A preliminary study

High b value diffusion weighted magnetic resonance imaging (high-b DWI) was used to characterize white matter changes in the brain of patients with vascular dementia (VaD). Hyperintense white matter areas detected by T2-weighted magnetic resonance imaging (MRI) represent lesions, also termed leukoaraiosis that are very common in VaD as well as in other types of dementia. Therefore, the role of white matter changes in the cognitive and memory decline that occurs in VaD patients is still under debate. High-b DWI, analyzed using the q-space approach, is a more sensitive MRI method for detection of white matter changes. High-b DWI revealed massive white matter loss in VaD patients that surpassed the boundaries of T2 hyperintensities. This technique, therefore, might serve as a better indication for the extensive nerve fiber loss in the white matter that is caused by vascular disease.

Synovial effusion in reflex sympathetic dystrophy: an additional sign for diagnosis and staging

Abstract Purpose. To improve the present MRI criteria for diagnosis and staging of reflex sympathetic dystrophy (RSD) by including increased joint fluid as an additional MRI sign of RSD. Design and patients. One hundred and fourteen extremities (69 affected and 45 contralateral controls) in 57 consecutive patients with RSD were evaluated using a 1.5-T unit. T1- and T2-weighted pulse sequences, often with fat suppression, were used before and after administration of intravenous contrast enhancement (Gd). Following T2-weighted image digitization the volume of synovial fluid was measured with a computer model. Results. Effusions were detected in 61% of the extremities suspected of RSD and in 44% of the contralateral control joints. The mean fluid quantity measured in the symptomatic articulation was 201 mm3. MRI diagnosis of RSD based on previously described criteria was done in 62% of the patients, yielding a sensitivity of 60%. Effusions were present in 79% of the false negative MRI cases. Retrospectively considering the presence of fluid as a potential positive criterion for RSD increases the sensitivity by 31% (to 91%). Conclusions. Joint effusions are probably associated with early stages of RSD. Adding effusion to the list of radiological criteria for RSD increases the sensitivity of MRI from 60% to 91%.

High b-value diffusion imaging of dementia: application to vascular dementia and alzheimer disease.

Alzheimers disease (AD) and Vascular Dementia (VaD) are the most common types of dementia and are progressive diseases affecting millions of people. Despite the high sensitivity of MRI to neurological disorders it has not thus far been found to be specific for the detection of either of these pathologies. In the present study high b-value q-space diffusion-weighted MRI (DWI) was applied to VaD and AD. Controls (N=4), VaD patients (N=8) and AD patients (N=6) were scanned with high b-value DWI, which emphasizes the water component which exhibits restricted diffusion. VaD patients were found to present major WM loss while, in AD, the major pathology found was GM changes, as expected. Also, WM changes in VaD and AD were of a different pattern, more specific to frontal and temporal areas in AD and more widespread in VaD. This pattern of WM changes may be utilized as a diagnosis criterion. Conventional diffusion tensor imaging did not show significant changes between either of the groups and controls. These results demonstrate the potential of high b-value DWI in the diagnosis of dementia.

Radioimmunoguided surgery benefits for recurrent colorectal cancer.

AbstractBackground: Despite new adjuvant therapy, 50% of patients with colon cancer will have recurrent disease. This study investigated the use of a radiolabeled monoclonal antibody in locating occult tumor during surgery for recurrent colorectal cancer. Methods: Twenty-two patients with recurrent colorectal cancer underwent surgery using the radioimmunoguided surgery (RIGS) system. All patients were subjected to abdominal and chest computed tomography (CT). Before surgery, patients were injected with the CC49 monoclonal antibody (MoAb), anti-TAG antibody labeled with125I. Ten patients with elevated carcinoembryonic antigen (CEA) levels and no CT findings had a scintigraphy scan with an anti-CEA MoAb labeled with99Tc. Human antimouse antibody levels of these patients were within normal limits. Surgical exploration including liver ultrasound examination was followed by survey with a gamma-detecting probe (GDP). Results: There was MoAb tumor localization in 100% of the patients. CT found nine tumor sites, traditional surgical exploration 30, and the GDP 51, with 44 confirmed by pathology (hematoxylin and eosin). The RIGS system found occult tumor in 10 patients (45.4%) and resulted in major changes in surgical procedure in 11 patients. In the 10 patients who had scintigraphy scans, 10 tumor sites were identified, whereas RIGS found an additional eight sites. Conclusion: RIGS technology offers a substantial benefit for patients undergoing surgery for recurrent colorectal cancer and a better chance of finding recurrent tumor intraoperatively in patients who have elevated CEA levels with no other CT findings.

Pseudoaneurysm of the inferior epigastric artery mimicking abdominal wall hematoma

A 67 year old woman underwent surgical repair of a nonreducible umbilical hernia. The immediate postoperative course was uneventful. Two weeks later, during the removal of one of the retention sutures on an outpatient basis, she experienced a sudden, severe pain at the incision site. She was released without further evaluation. Two days later she was readmitted on an emergency basis because of intractable pain. Physical examination revealed

Further development of reconstructive and cell tissue-engineering technology for treatment of complete peripheral nerve injury in rats

Abstract In this work we evaluated the efficacy of biodegradable composite co-polymer guiding neurotube, based on tissue-engineering technology, for the treatment of complete peripheral nerve injury where the nerve defect is significant. The right sciatic nerve of 12 three-month-old rats was completely transected and peripheral nervesegment was removed. A 2.2-cm biodegradable co-polymer neurotube containing viscous gel (NVR-N-Gel) with survival factors, neuroprotective agents and Schwann cells was placed between the proximal and the distal parts of the transected nerve for reconnection a 2-cm nerve defect. The proximal and distal parts of the nerve were fixed into the neurotube using 10-0 sutures. Ultrasound observation showed growth of the axons into the composite neurotube 2 months after the surgery. Electrophysiological study indicated compound muscle action potentials in nine out of 12 rats, 2-4 months after peripheral nerve reconstructive surgery. The postoperative follow-up (up to 4 months) on the operated rats that underwent peripheral nerve reconstruction using composite co-polymer neurotube, showed beginning of re-establishment of active foot movements. The tube was dissolved and nerve showed complete reconnection. Histological observation of the nerve showed growth of myelinated axons into the site where a 2-cm nerve defect replaced by composite co-polymer neurotube and into the distal part of the nerve. In conclusion: (1) an innovative composite neurotube for reconstruction of significant loss of peripheral nerve segment is described; (2) a viscous gel, containing survival factors, neuroprotective agents and Schwann cells served as a regenerative environment for repair. Further investigations of this reconstructive procedure are being conducted.