Cerebral venous system anatomy

Cerebral venous system can be divided into a superficial and a deep system. The superficial system comprises of sagittal sinuses and cortical veins and these drain superficial surfaces of both cerebral hemispheres. The deep system comprises of lateral sinus, straight sinus and sigmoid sinus along with draining deeper cortical veins. Both these systems mostly drain themselves into internal jugular veins. The veins draining the brain do not follow the same course as the arteries that supply it. Generally, venous blood drains to the nearest venous sinus, except in the case of that draining from the deepest structures, which drain to deep veins. These drain, in turn, to the venous sinuses. The superficial cerebral veins can be subdivided into three groups. These are interlinked with anastomotic veins of Trolard and Labbe. However, the superficial cerebral veins are very variable. They drain to the nearest dural sinus. Thus the superolateral surface of the hemisphere drains to the superior sagittal sinus while the posteroinferior aspect drains to the transverse sinus. The veins of the posterior fossa are variable in course and angiographic diagnosis of their occlusion is extremely difficult. Blood from the deep white matter of the cerebral hemisphere and from the basal ganglia is drained by internal cerebral and basal veins, which join to form the great vein of Galen that drains into the straight sinus. With the exception of wide variations of basal vein, the deep system is rather constant compared to the superficial venous system. Hence their thrombosis is easy to recognize

Intra-abdominal desmoplastic small round cell tumor

Intra-abdominal desmoplastic small round cell tumor [IDSRCT] is a unique, highly aggressive neoplasm that chiefly affects male adolescents and young adults and most frequently presents as a large abdominal mass with widespread peritoneal involvement at the time of diagnosis. We present two cases of IDSRCT in a young male and a female. Both typically presented with diffuse peritoneal involvement

Role of focused appendiceal computed tomography in clinically equivocal acute appendicitis

To determine the accuracy of FACT [focused appendiceal computed tomography] in evaluation of acute appendicitis. The study was conducted in Aga Khan University Hospital, Karachi, over a period of one year. Sixty-three patients with clinically equivocal acute appendicitis underwent thin-section non-enhanced helical CT. Axial scans were obtained in a single breath hold from L2 vertebral level to the pubic symphysis with 5-mm collimation and a pitch of 1.5. All scans were obtained without oral, intravenous, or rectal contrast material. Criteria for diagnosis of acute appendicitis included an enlarged appendix [>6 mm diameter] and periappendiceal inflammation. Final diagnoses were established with the results of surgical or clinical follow-up. There were 21 true-positive diagnoses, 38 true-negative diagnoses, no false-positive diagnoses, and 2 false-negative diagnoses, which yielded a sensitivity of 91% and a specificity of 100%. Non-enhanced FACT is a highly accurate problem solving technique in clinically equivocal cases of acute appendicitis

Non contrast helical CT scan for acute flank pain: non calculus urinary and extra urinary causes

To determine the value of non contrast helical CT in the diagnosis of non calculus renal and extraurinary causes of acute flank pain. A prospective descriptive study. Radiology Department, Aga Khan University Hospital Karachi from January 2005 to June 2005. 130 consecutive patients with acute flank pain underwent Noncontrast enhanced helical CT scan [NHCT]. 100[73%] were male and 30[23%] were female. Scans were observed for noncalculus renal and extraurinary causes of acute flank pain. Out of 130 patients, 30 patients were excluded. In 23[23%] patients non calculus causes of pain were diagnosed. In 5 [5%] patients incidental findings were recorded which were most likely not cause of pain. Three patients had non calculus renal abnormalities which included renal cell carcinoma, horseshoe kidney adult polycystic kidney disease. The accurate and timely diagnosis of an obstructing ureteral calculus, a non calculus urinary abnormality or an extra urinary tract pathology, establishes non contrast helical CT as the diagnostic study of choice for the evaluation of patients with flank pain

Lhermitte Duclos disease [dysplastic cerebellar gangliocytoma]

This case report describes an adult male presenting with ataxia. Dysplastic cerebellar gangliocytoma, the Lhermitte- Duclos disease, was diagnosed on neuroimaging. Diagnosis was confirmed on histopathology of surgically removed lesion. Patient underwent an uneventful recovery following operative treatment

Cerebral deep venous thrombosis: case report and literature review

The case of a 28 years old woman presenting with headache, drowsiness and vomiting of a short duration, is presented. She was diagnosed as deep cerebral venous thrombosis on the basis of MRI findings. Treatment with heparin gave completed recovery

Role of magnetic resonance imaging in lumbar spondylosis

To assess the frequency of various MRI findings in patients with lumbar spondylosis and determine their association with symptoms of patients. Cross-sectional analytical study. Radiology Department,The Aga Khan University Hospital, Karachi, from January to December, 2002. The study included 120 patients who presented with low back and leg pain. Segmental classification system was used to classify the pain distribution. All patients underwent lumbar MRI using 1.5 T-scanner. MRI scans was evaluated for magnitude and location of nerve compression, disc extrusion and the nature of nerve and thecal sac deformation in the central canal, lateral recess and intervertebral foramen at each spinal level. Statistical analysis was performed using computer program SPSS [Version; 10]. Chi-square test was also used to determine significance of association between degree of compression, duration of symptoms, site of pain and presence of weakness and numbness. Independent samples test [Levenes test] and Chi-square test were used to determine the significance of associations between age, gender, chronicity of symptoms and MRI findings. A p-value of <0.05 was considered to indicate statistically significant association. The study included 120 patients, the age range was 22 to 88 years [mean 47 years]. Twenty-three patients had acute pain of less than 2 months, 40 patients had recurrence of previous symptoms within past 2 months and 57 patients had chronic pain. Disc herniation was most frequent finding seen in 107 patients [89%]. Eighty-eight patients [73%] had MRI evidence showing some degree of nerve or thecal sac compression. Severe nerve compression was present in 48 patients [40%]. Disc extrusion was present in 22 patients [18%]. There was no significant association between segmental distribution of symptoms and presence of anatomic impairment. However, severe nerve compression and disc extrusion were significantly associated with pain distal to the knees. The presence of disc extrusion or ipsilateral severe nerve compression at one or multiple side is strongly associated with distal leg pain. There should be a correlation between patient symptoms and signs of sciatica and imaging demonstration of nerve root compression before invasive therapy is undertaken

Unenhanced helical CT scan for ureterolithiasis

The study was carried out from November 2002 to January 2004 and included patients who presented with flank pain at the Aga Khan University Hospital. One hundred and twenty patients were excluded from the study that were less than 15 years of age, pregnant or had history of trauma and infection. A total of 80 out of these 200 patients were included in this study that had a CT diagnosis of ureteric calculus after a UEHCT. In all those 80 patients with diagnosis of ureteric calculus on CT scan was confirmed later on either IVU, stone passage in the urine, ESWL [extracorporeal shock wave lithotripsy] or on the ureteroscopic removal of calculus. The images were interpreted for site, size and location of ureteric calculus, hydronephrosis, hydroureter, perinephric stranding, periureteral stranding, nephromegaly and incidental findings. The age range was 15-69 years, with a mean age of 37.5 years. Out of 80 patients, 32 [40%] patients presented with right sided flank pain and 48 [60%] of the patients had left sided flank pain. In 12 [15%] patients, calculi were present in the proximal ureter, in 24 [30%] in the mid ureter and in 44 [55%] in distal ureter. Most of the stones were between 3-5 mm size range [47%]; 20% stones were less than 3 mm in size and 32.5% of stones were more than 5 mm in size. Most common secondary sign was perinephric stranding seen in 48 patients [60%]. The second most common secondary sign was periureteral stranding seen in 44 [55%] patients. In 30 of the patients [37.5%] hydronephrosis was observed. In 18 [22.5%] hydroureter was present. Nephromegaly was observed in 2.3% of the patients. In 2 of 120 patients in which CT was negative, ureteric calculus was present on IVU which was carried out 3 days after UEHCT. In 2 of 120 patients in which CT was negative for ureteric calculus, ureteric calculus was present on IVU which was carried out 3 days after UEHCT. The sensitivity, specificity, positive and negative predictive values of unenhanced helical CT scan for detection of ureteric calculi was 97.5%, 98.3%, 97.5% and 98.3% respectively