Does routine MR contrast enhancement correlate with internal thrombosis in cerebral cavernous malformations? A radiological-histopathological correlation in a case series

Objectives: It is well known that cerebral cavernous malformations (CCMs) present with variable degrees of contrast enhancement on routine magnetic resonance imaging (MRI) studies. This is attributed to the presence of a low flow vascular architecture in these lesions. The aim of this preliminary study was to determine whether an additional reason for the different degree of contrast enhancement could be the degree of internal thrombosis. Material and methods: Fourteen consecutive patients with surgically removed CCMs were included. In all patients, standard preoperative MRI (1.5 Tesla, T1 weighted images without and with contrast agent, slice thickness 5 mm, 0.1 mmol gadolinium/kg body weight, and delay similar to 5 minutes) and a histological specimen were available. The degree of contrast enhancement (none, little, moderate, and marked) was rated by two independent neuroradiologists blinded to the results of histopathology. The degree of internal thrombosis (none, little, moderate, and marked) was rated by a neuropathologist blinded to the results of MRI. Results: Contrast enhancement was visible in six (43%) CCMs (Cohen's kappa=0.76 or substantial). The degree of contrast enhancement was not dependent on the degree of internal thrombosis (P=0.1, Fisher's exact test) and did not correlate with it (r=0.06, P=0.83, Pearson's correlation coefficient). Conclusion: The flow characteristics of CCMs seem to be the main factor contributing to the degree of contrast enhancement while the degree of internal thrombosis does not influence their contrast affinity.