Spinal Cord Cavernous Malformations: MRI Commonly Shows Adjacent Intramedullary Hemorrhage

Background and purpose: There is a relative paucity of radiology literature on spinal cord cavernous malformations (SCMs). We hypothesized that the classic MRI features of cavernous malformations are not highly prevalent. The purpose was to review MR imaging findings of SCMs with a focus on prevalence of hemorrhagic features, including adjacent intramedullary hemorrhage at initial presentation.

Methods: In this single-institution study, 78 SCMs in 76 patients diagnosed on imaging/pathology were retrospectively evaluated for size, location, cord expansion, exophytic component, popcorn morphology, signal characteristics, including T1 weighted (T1w) and T2w rims, blood-fluid levels, and adjacent intramedullary hemorrhage. Intramedullary hemorrhage was defined as centrally and/or eccentrically located linear or flame shaped non-edematous signal abnormality extending longitudinally away from SCMs, distinct from lesional rim.

Results: Sixty-three percent (49/78) of SCMs measured <1 cm in length, 78% (61/78) extended to the cord surface, 65% (51/78) were expansile, and 32% (25/78) were exophytic. Popcorn morphology was seen in 15% (12/78) on T1w and 22% (17/78) on T2w. Internal blood-fluid levels were evident in 4% (3/78). Sixty-nine percent (54/78) showed T2w hypointense rims; the T2w rim was complete/near-complete in 37% (29/78). A rim on T1w was visible in 49% (38/78); this was hyperintense in 58% (22/38). Adjacent intramedullary hemorrhage was seen in 45/78 (58%), was most commonly bidirectional in 67% (30/45) and eccentric in 68% (30/44). Cord edema was seen in 22% (17/78); 53% (9/17) also demonstrated intramedullary hemorrhage with edema.

Conclusions: The classically described popcorn morphology, internal blood-fluid levels, and complete/near-complete T2w hypointense rims are often absent on MRIs in SCMs. Adjacent intramedullary hemorrhage is frequently present, often eccentric and bidirectional.