Muhammad Azeemuddin

Neuroimaging of cerebral venous thrombosis

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 Δ 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.

Encephalitis and myelitis associated with dengue viral infection clinical and neuroimaging features.

OBJECTIVES The objective of this study was to identify clinical and neuroimaging features and outcome of patients with encephalitis and myelitis associated with dengue viral infection. PATIENTS AND METHODS We retrospectively reviewed 225 cases of dengue viral infection. The diagnosis of dengue was confirmed by serology (presence of IgM antibodies). RESULTS Six patients (3%) had evidence of neurological infection (encephalitis: 5 patients; encephalomyelitis: 1 patient). Age range was 18-35 years (Mean 27 years). Five patients (83%) were women. All patients (100%) had drowsiness, five patients (83%) had fever, four patients (67%) presented with seizures and one patient presented with paraparesis (16%). All patients had elevated CSF cell count (range 25-102; mean 61) with predominant lymphocytes. Five patients (83%) had abnormal CT or MRI scan. Cerebral edema was present in three patients. Other findings included low density signals in right temporal and occipital lobe (1 patient), bi temporal hyperintensities and meningeal enhancement (1 patient), Frontal and subcortical hyperintense lesion (1 patient) and hyperintense lesion on T2 in Pons and cervical and thoracic spinal cord (1 patient). EEG was done in four patients and showed generalized slowing (2 patients), bi temporal spikes (1 patient) and burst suppression pattern (1 patient). Two patients (32%) died and one patient was discharged in bedridden state. CONCLUSION The involvement of brain and spinal cord is uncommon in dengue viral infection. Most patient present with seizures. Neuroimaging features are diverse. Prognosis is poor in patients presenting with encephalitis or myelitis.

Frequency and Outcome of Carotid Atheromatous Disease in Patients With Stroke in Pakistan

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 ≥6 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. The local socio-economic and clinical data do not support routine carotid Doppler ultrasound in every patient with stroke and TIA in Pakistan. Studies are warranted to determine predictors of significant carotid artery stenosis in stroke/TIA patients of our country to develop reliable stroke guidelines appropriate for local population.

Incidental MRI lesions suggestive of multiple sclerosis in asymptomatic patients in Karachi, Pakistan

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.

Cerebral Venous Sinus Thrombosis: Association with Primary Varicella Zoster Virus Infection

Varicella zoster virus (VZV) has been known to cause cerebral arterial vasculopathy and an acquired antibody-mediated coagulopathy associated with purpura fulminans and generalized thromboembolism. There are no published reports of cerebral venous sinus thrombosis (CVST) associated with primary VZV infection. We report 2 cases that highlight an unusual presentation of VZV infection: CVST with primary varicella infection. One patient had extensive CVST with coexistent middle cerebral artery involvement. Primary VZV infection can be associated with thrombosis of cerebral arteries and venous sinuses.

Treatment of Nonvariceal Gastrointestinal Hemorrhage by Transcatheter Embolization

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.

Diagnostic Accuracy of Ultrasonography in Differentiating Benign and Malignant Thyroid Nodules Using Fine Needle Aspiration Cytology as the Reference Standard

BACKGROUND In Pakistan thyroid cancer is responsible for 1.2% cases of all malignant tumors. Ultrasonography (US) is helpful in detecting cancerous thyroid nodules on basis of different features like echogenicity, margins, microcalcifications, size, shape and abnormal neck lymph nodes. We therefore aimed to calculate diagnostic accuracy of ultrasound in detection of carcinoma in thyroid nodules taking fine needle aspiration cytology as the reference standard. MATERIALS AND METHODS A cross-sectional analytical study was designed to prospectively collect data from December 2010 till December 2012 from the Department of Radiology in Aga Khan University Hospital, Karachi, Pakistan. A total of 100 patients of both genders were enrolled after informed consent via applying non-probability consecutive sampling technique. Patients referred to Radiology department of Aga Khan University to perform thyroid ultrasound followed by fine-needle aspiration cytology of thyroid nodules were included. They were excluded if proven for thyroid malignancy or if their US or FNAC was conducted outside our institution. RESULTS The subjects comprised 76 (76%) females and 24 males. Mean age was 41.8±SD 12.3 years. Sensitivity and specificity with 95%CI of ultrasound in differentiating malignant thyroid nodule from benign thyroid nodule calculated to be 91.7% (95%CI, 0.72-0.98) and 78.94% (0.68-0.87) respectively. Reported positive predictive value and negative PV were 57.9% (0.41-0.73) and 96.8% (0.88-0.99) and overall accuracy was 82%. Likelihood ratio (LR) positive was computed to be 4.3 and LR negative was 0.1. CONCLUSIONS Ultrasonography has a high diagnostic accuracy in detecting malignancy in thyroid nodules on the basis of features like echogenicity, margins, micro calcifications and shape.

Meningioma-like lesions in Erdheim Chester disease

A 55-year-old female patient, a hypertensive, was admitted with generalized tonic clonic seizures, fever, cough, and drowsiness. Her symptoms had started 1 month back. Detailed work-up was done, and she was diagnosed to have diabetes insipidus. Her laboratory investigations showed hypernatremia with serum sodium level of 170, WBC count was 21.2, ESR was 94, and C-reactive protein was 20.5. Her chest X-ray showed osteopenia of visualized bone with patchy bony density at lateral ends of both clavicles. Radionuclide skeletal scintigraphy revealed diffusely increased tracer uptake over appendicular skeleton and left hemipelvis, with evidence of bony expansion and photon deficiencies more marked over the proximal one third of both femur and left Sacroiliac joint. She underwent brain MRI with gadolinium, which revealed multiple extra-axial masses along the bilateral cerebral convexities, intraventricular region involving occipital horn of left lateral ventricle, and along tentorium and falx. These were associated with mild surrounding edema causing effacement of adjacent cortical sulci and pressure on body of right lateral ventricle. These showed isointense signals on T1-weighted image and hypointense signals on T2-weighted images. Post contrast images showed intense homogenous enhancement of masses (Fig. 1). Based on these findings, a most probable diagnosis of meningiomatosis was suggested. To confirm the diagnosis of meningiomas, the patient was subjected to biopsy of lesion along the right cerebral convexity. A diagnosis of xanthogranulomatous lesion was made. Correlating with the clinical and radiographic features, these lesions were consistent with manifestations of ECD. She was put on azathioprine, thyroxine, desmopressin, esomeprazole. After a week, the patient was clinically stable, oriented, tolerating oral well, and her fever settled.

An unsuspected bleeding Meckel's diverticulum in an adult detected on mesenteric angiography

Meckels diverticulum is usually asymptomatic and found in almost 2% of the population. Haemorrhage from a Meckels diverticulum is common in children but rare in adults. Here we report a case of 20 years old male with recurrent gastrointestinal bleeding. Meckels diverticulum was diagnosed due to abnormal vascularity on mesenteric angiography and embolization was performed. Diagnosis was correlated with other radiological imaging and later elective resection was performed. This case is reported to emphasize the potential role of mesenteric angiography in the detection and management of bleeding Meckels diverticulum and correlation with other radiological imaging.

Posterior reversible encephalopathy syndrome.

OBJECTIVE To evaluate the Magnetic Resonauce Imaging (MRI) features in patients having Posterior Reversible Encephalopathy Syndrome. METHODS This is a retrospective study from 8th June 2005 to 26th July 2009. Twelve patients were included who were confirmed to have Posterior Reversible Encephalopathy Syndrome, per imaging and clinical follow-up. Two neuro-radiologists blinded to the clinical condition retrospectively reviewed each image. Standard sequences were unenhanced Fluid Attenuated Inversion Recovery (FLAIR), T1-weighted, T2- weighted images followed by diffusion-weighted imaging and contrast-enhanced T1-weighted imaging. The regions involved were recorded on the basis of these sequences. RESULTS Abnormal T2-weighted hyperintense signals (indicating vasogenic oedema) were consistently present in the parietal or occipital regions in 5 (41.6%), but other locations were also involved, including the deep white matter in 3 (25%), frontal lobes in 1, inferior temporal lobes in 1, cerebellar hemispheres in 1, and basal ganglia in 1 (8.3% each). On follow-up examination after 5-7 weeks, the patients showed marked improvement clinically and on neuro-imaging, and were discharged in a stable condition. After administration of gadolinium contrast, there was no area of abnormal enhancement in 11 cases and minimal enhancement was seen in 1 case. In our series, 3 patients had follow-up MRI examination which revealed the resolution of previously seen changes as well as the resolution of clinical symptoms. However, the diagnosis of Posterior Reversible Encephalopathy Syndrome was established in 9 other patients by resolution of clinical symptoms alone in 2-3 weeks. CONCLUSION Awareness of diverse clinical and radiographic presentation of acute Posterior Reversible Encephalopathy Syndrome is essential to avoid misdiagnosis and treatment delay. Moreover, the syndrome is reversible with prompt treatment and has good outcome. This case series confirmed clinical improvement and recovery in most patients within weeks.