ABSTRACT
Purpose: Hirayama disease (HD) is a rare disease that was commonly mis-diagnosed in the past. The importance of neutral and flexion magnetic resonance imaging (MRI) in its accurate diagnosis has been emphasized along with utility of the inter-segmental angle of flexion. Aim of the study was to observe MRI findings of HD in neutral and flexion position and measure the inter-segmental angle of flexion. Material and methods: Cervical MR images of 17 patients of suspected HD were evaluated retrospectively for loss of attachment (LOA) of posterior dura, lower cervical cord atrophy, T2 hyperintensity, loss of cervical lordosis, enhancement of posterior epidural venous plexus, and inter-segmental angle of flexion on neutral and flexion MRIs. Results: Flexion MRI showed LOA of posterior dura (most commonly and maximum at C6 vertebral level) and intense enhancement in posterior epidural space in almost all patients. The mean inter-segmental angle of flexion at C5-C6 was 9.2°, and at C6-C7 it was 6°. Neutral MRI revealed LOA in 64.7%, lower cervical cord atrophy in all patients, T2 hyperintensity in the lower cervical cord in 35.2% of patients, and loss of cervical lordosis in 58.8% of patients. Conclusions: Flexion MRI is the gold standard for diagnosis of HD; however, certain imaging attributes, i.e. loss of attachment of posterior dura, asymmetrical lower cervical cord atrophy, T2 hyperintensity, and loss of cervical lordosis, can be seen on neutral MRI as well, which subsequently prompts the radiologist to include flexion MRI for confirmation. The inter-segmental angle of flexion is increased in patients with HD, which plays a role in planning timely surgical intervention.
ABSTRACT
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.
