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Early and accurate diagnosis of cerebral venous thrombosis (CVT) is possible with the help of computed tomography (CT) scan and magnetic resonance imaging (MRI). Empty delta sign on postcontrast CT is present in only up to 30% of the cases. The role of CT venography is not yet established, but it is emerging as an effective modality for diagnosis of CVT. T2* MRI sequence is superior to spin echo in detecting CVT and small hemor rhages. MR venography is considered the technique of choice for diagnosis and follow-up of CVT, but in certain cases, MRI could be superior as it shows the thrombus itself and not just the absence of signal as seen on MR venography. Diffusion-weighted imaging is a relatively new MRI technique that is extremely sensitive in detecting acute arterial strokes and can distinguish cytotoxic and vasogenic edema. The presence of hyperintense signal on diffusion-weighted imaging in the occluded veins or sinuses at the time of diagnosis may predict a low rate of vessel recanalization. Contrast angiography should be strongly considered if isolated cortical vein thrombosis is suspected.

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BACKGROUND AND PURPOSE There is a paucity of literature related to the neuroimaging of CNS tuberculosis (TB) and largely covers pediatric CNS TB. The objective of this study was to determine the frequency of different forms of CNS TB and its associated complications and to study longitudinal disease course using computed tomography (CT) and MRI. METHODS Retrospective chart and imaging review of patients diagnosed with CNS TB in a tertiary care hospital in Pakistan over a 10‐year period. A total of 452 initial brain MRI and 209 CT scans were reviewed by an expert radiologist specialized in neuroimaging. This was followed by review of 53 MRI/52 CT and 7 MRI/14 CT first and second follow‐up scans, respectively. RESULTS Note that 559 patients, 296 males and 263 females were included in the study. On the initial CT scans, tuberculomas were found in 25 (12%), infarction in 54 (25%), basal meningeal enhancement in 29 (14%), and hydrocephalus in 84 (40%). On initial MRI, tuberculomas were found in 182 (40%), infarction in 120 (27%), basal meningeal enhancement in 184 (41%), and hydrocephalus in 116 (26%). On review of follow‐up CT scans, 13 (25%) showed new or worsening hydrocephalus, 8 (15%) showed new infarcts, 1 exhibited new tuberculoma, and 5 showed worsening cerebral edema. On review of follow‐up MRI scans, new or worsening hydrocephalus was seen in 3 (6%), new infarcts in 3 (6%), new tuberculoma in 10 (19%), worsening cerebral edema in 7 (13%), and TB myelitis in 4 (8%) patients. CONCLUSIONS Tuberculoma, hydrocephalus, and cerebral infarcts are the most prominent findings in CNS tuberculosis. Our study showed development of new lesions on subsequent neuroimaging suggesting a dynamic and progressive nature of the disease process in some individuals.

Background and Purpose-Limited data exist on the frequency and outcome of carotid artery disease in Pakistan. Such information would help guide the usefulness of screening for the condition in this low-middle income health care setting. Methods-A prospective, descriptive study was conducted among 3 large teaching hospitals in Karachi, Pakistan. Patients referred for carotid Doppler ultrasound examination were included if they had experienced a stroke or TIA within the previous month. The severity and morphology of carotid disease were characterized by trained technicians using standardized criteria. Demographic and risk factor data were collected at baseline, and the outcome of patients was assessed at least 6 months later. Results-A total of 672 patients underwent bilateral carotid Doppler ultrasound (1344 carotid examinations). The findings revealed 0% to 50% stenosis in 526 (78%), 51% to 69% stenosis in 57 (8%), 70% to 99% stenosis in 82 (12%), and total occlusion in 7 patients (1%). Potentially surgically correctable disease, defined as 70% to 99% carotid artery stenosis, was present in only 79 (12%) patients, of whom 47 (60%) were ipsilateral symptomatic, 15 (20%) asymptomatic, and 17 (20%) had status unknown. Outcome information at Ն6 months follow-up was available for 36 of the 47 (76%) surgically correctable and only 4 of these patients (12%) had undergone surgical or radiological intervention (carotid endarterectomy in 3 patients and carotid stenting in 1 patient). Conclusion-The frequency of carotid artery disease of at least moderate severity is very low in patients with recent stroke or TIA and there is low utilization of high-cost, carotid intervention procedures in Pakistan. These data raise questions regarding the applicability and cost-effectiveness of routine carotid ultrasound screening in our country and similar population in Asia.

Purpose. To investigate the sensitivity of mesenteric angiography, technical success of hemostasis, clinical success rate, and complications of transcatheter embolization for the treatment of acute nonvariceal gastrointestinal hemorrhage. Material and Methods. A retrospective review of 200 consecutive patients who underwent mesenteric arteriography for acute nonvariceal gastrointestinal hemorrhage between February 2004 and February 2011 was done. Results. Of 200 angiographic studies, 114 correctly revealed the bleeding site with mesenteric angiography. 47 (41%) patients had upper gastrointestinal hemorrhage and 67 (59%) patients had lower gastrointestinal hemorrhage. Out of these 114, in 112 patients (98%) technical success was achieved with immediate cessation of bleeding. 81 patients could be followed for one month. Clinical success was achieved in 72 out of these 81 patients (89%). Seven patients rebled. 2 patients developed bowel ischemia. Four patients underwent surgery for bowel ischemia or rebleeding. Conclusion. The use of therapeutic transcatheter embolization for treatment of acute gastrointestinal hemorrhage is highly successful and relatively safe with 98% technical success and 2.4% postembolization ischemia in our series. In 89% of cases it was definitive without any further intervention.

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The objective of this study was to identify asymptomatic patients with brain MRI lesions suggestive of multiple sclerosis (MS) in a low-prevalence area of Pakistan. Brain MRIs for 864 patients were reviewed at the Aga Khan University (Karachi, Pakistan) during an 8-month period of 2006 and 2007 to identify patients with lesions suggestive of MS. The lesions were characterised based on modified Barkhof criteria. Six (two females) (0.7%) of 864 patients fulfilled brain MRI criteria suggestive of MS. The mean number of MRI lesions (total lesions on T2) were 9 (range 5-14). Although Pakistan is considered a low-prevalence area for MS, 0.7% of brain MRI scans in patients without clinical MS symptoms showed lesions fulfilling brain MRI criteria of MS.