Diagnostic accuracy of diffusion weighted MRI in differentiating benign and malignant meningiomas.

OBJECTIVE: To determine the diagnostic accuracy of DWI in differentiating benign and malignant meningiomas keeping histopathology as gold standard. METHODS: This was a descriptive analytical study conducted at Radiology Department, DUHS/Dr. Ruth K. M. Pfau Civil Hospital Karachi, from August 2016 to March 2018.It included152 patients clinically suspected of meningioma on conventional neuroimaging. Imaging features of DWI were compared with histopathology findings. The diagnostic accuracy of DWI was calculated in terms of sensitivity, specificity, accuracy, PPV and NPV using histopathology as gold standard. RESULTS: There were 59 male and 93 female patients with mean age of 55.38±9.8 years. Mean duration of sign and symptoms was 5.67±2.57 months. Out of 152 patients, 117(77%) and 35(23%) were differentiated into benign and malignant meningiomas respectively by DWI while 135(88.82%) and17(11.18%) patients were diagnosed respectively on histopathology. The sensitivity, specificity, PPV, NPV and accuracy of DWI of 84.4%, 82.3%, 97.4%, 40%, and 84.2% respectively keeping histopathology as gold standard. CONCLUSION: DWI features along with calculation of ADC values is a reliable non-invasive technique for differentiating benign and malignant meningiomas. However the low negative predictive value necessitates the use of histopathology.

MRA-based evaluation of anatomical variation of circle of Willis in adult Pakistanis.

OBJECTIVE: To determine the frequency and patterns of normal anatomical variation of Circle of Willis on magnetic resonance angiogram in adults without cerebrovascular disease. METHODS: This descriptive cross-sectional study was conducted at the Radiology Department of Dow University of Health Sciences / Civil Hospital, Karachi, from January to December 2016, and comprised patients referred for magnetic resonance imaging of the brain and magnetic resonance angiogram without any clinical or radiological manifestation of cerebrovascular disease, primarily including those with suspected demyelination, infection, epilepsy or metastases. Three-dimensional time-of-flight magnetic resonance angiography was performed. The Circle of Willis was assessed for its completeness along with anatomical variations of anterior and posterior components of the circle. RESULTS: Of the 135 subjects, 70(51.8%) were males and 65(48.2%) were females with an overall mean age of 49.26±9.2 years. Among all the subjects, 30(22.2%) showed a complete circle, while 82 (60.7%) and 23(17.1%) had partially complete and incomplete circles respectively. The anterior part of the circle was completed in 108 (80%) subjects, showing type 'a' as the most common variant in 93(68.9%). The posterior part of the circle was completed in 30 (22.2%) subjects with type 'e' variant in 52(38.5%). CONCLUSIONS: There was a wide variability in the anatomy of the Circle of Willis in Pakistani adults asymptomatic for cerebrovascular disease.

Pseudoaneurysm of Left proximal Common Carotid Artery following penetrating trauma.

A 33-year male with history of penetrating trauma to left upper chest in 2006, presented through Medical unit to Radiology Department with complain of hemoptysis. Chest X-ray showed a soft tissue lesion in left upper lobe with a linear metallic foreign body. Contrast enhanced CT scan of chest and later CTA was performed which showed a saccular aneurysm arising from mediastinal part of left common aortic artery surrounded by thrombosis with a cylindrical linear metallic foreign body. He was planned for endovascular repair with stenting which he could not afford due to financial constraints. He is currently on conservative follow up. Vascular lesions can be serious complications resulting from blunt or penetrating trauma, when presenting with hemoptysis due to pseudaoneurysms formation even after so many years of trauma.