MR imaging of cavernous sinus thrombosis

PURPOSE: To determine the role of Contrast enhanced MRI (CEMRI) in the evaluation of Cavernous sinus thrombosis (CST). METHOD: The study included 7 patients with an imaging diagnosis of cavernous sinus thrombosis. A retrospective analysis of Contrast enhanced MRI of 9 affected cavernous sinuses and a control group of 7 patients (14 cavernous sinuses) was conducted. Various qualitative and quantitative parameters were then compared. RESULTS: In the patient group, the mean Cavernous sinus (CS) diameter, Cavernous Internal Carotid Artery (ICA) diameter and Superior Ophthalmic Vein (SOV) diameter were 9.14 ± 0.56 mm, 3.5 mm ± 0.9 mm and 3.8 mm ± 1.79 mm respectively. While in the control group, the mean CS diameter, ICA diameter and SOV dimeter were 6.58 ± 0.54 mm, 4.6 mm ± 0.44 mm and 1.1 mm ± 0.11 mm respectively. The differences in the CS size, ICA and SOV diameters was statistically significant. (p < 0.05). Cut off points of ≥ 10 mm for CS diameter, ≥ 2.9 mm for SOV dilation, and ≤ 4.2 mm for ICA flow void diameter were estimated using receiver operating characteristic curves. Various other qualitative parameters, like bulging lateral walls of the sinus, heterogenous signal intensity with filling defects on post contrast images, abnormal dural enhancement along the lateral wall of the sinus and orbital apex involvement were more frequently observed in the CST group, in comparison to the control group. CONCLUSIONS: CEMRI plays an invaluable role not only in the diagnosis of cavernous sinus thrombosis, but also in evaluating the extent of disease and its associated complications. The quantitative and qualitative parameters described here, provide more objectivity and accuracy in diagnosis of CST, thus, aiding prompt diagnosis and early treatment.