Objective To evaluate the role of digital subtraction angiography (DSA) in the detection of intracranial aneurysms among patients with spontaneous subarachnoid hemorrhage (SAH) compared with computed tomographic angiography (CTA) in a single center, Sri Lanka. Methods A total of 123 patients clinically and CT proven SAH were evaluated with CT angiography and DSA with a median interval of 3 days. The sensitivity, specificity and accuracy of CT angiography in detecting aneurysms were analyzed compared to DSA on a perpatient, per-size, per-site and per morphological basis. All data were analyzed using SPSS analytical package (version 18). Ethical approval for the study was from the institutional ethical review board. Results Among 123 patients with clinically and CT proven SAH, 51 (41.5%) patients showed aneurysms on CT angiography. 72 were negative for aneurysms in CTA. In 13 out of 72 (18%) CTA negative patients subsequent DSA demonstrated aneurysms. Number of CTA negative but DSA positive aneurysm were 15 as two of the patients had two aneurysms each. Four CTA detected aneurysms could not be appreciated in the subsequent DSAs. Aneurysms (47) detected by both CT angiography and DSA were more than 6mm in size (56.7%) , saccular type (96.5%) and were located in the anterior circulation system (92.4%). Most CTA negative aneurysms detected by DSA were less than 6mm in size (80%), saccular type (60%) and were located in anterior (53.8%) and posterior (46.7%) circulation system. The sensitivity, specificity, positive predictive value and negative predictive value of CT angiography compared to DSA per patient basis were 78.3%, 93.7%, 92.2% and 81.9% respectively.

Background and ObjectiveThe carotid bifurcation (CB) is an important anatomical landmark and it is essential to have a thorough knowledge regarding the levels at which it bifurcates occurs in relation to the vertebral body level, especially in the fields of interventional radiology and surgery. MethodologyLateral projection of common carotid run with bony overlay was used to evaluate the level of CB in relation to 13 pre-determined levels. Images of 287 patients; 129 males and 158 females, from 6 to 88 years, who underwent digital subtraction cerebral angiography at a single center in Sri Lanka were included in study. ResultsHighest CB level was observed at right C2 in both males (n=1, 0.4%) and females (n=15, 4.9%). The lowest in males was seen at left C6/7 (n=1, 0.4%) and in females at C5/6 (n=1, 0.3%). C3 was the commonest CB level (n=174, 31.4%). CB level was found to be significantly lower in males (U=30109.5, p<0.001) and lower on left side (U= 33850.5, p = 0.014). Bilaterally symmetric CBs were seen in 136 (50.9%), which was commoner among females (M:F of 1:1.3) and occurred most frequently at C3 (n = 49, 18.4%).Average mid-cervical internal carotid artery (ICA) diameter was 4.1mm ± 0.9mm and 4.0mm ± 0.8mm and length was between 3.5cm -12.0cm and 2.9mm to -10.9mm in males and females respectively. No correlation was found between neck length and the level of CB (p = 0.099). ConclusionThe CB level ranging from the highest at C2 to the lowest at C6/7 with the most frequent level of bifurcation being at C3 corresponds to the other available international studies. Similarly, the prevalence of symmetric CBs was also comparable. Mean ICA diameter in our study was lower compared to other studies and may prove to be a useful predictor in local clinical practice.