Postoperative imaging evolution of preserved CCM-associated venous structures after cerebral cavernous malformation surgery: a retrospective case series

To describe the postoperative imaging evolution of preserved cerebral cavernous malformation (CCM)-associated venous drainage structures and their clinical context after microsurgical resection. Fifteen patients with solitary sporadic intracranial CCMs who underwent microsurgical resection between 2015 and 2025 were retrospectively reviewed. Early postoperative 1.5-T magnetic resonance imaging (MRI) was obtained 2–3 months after surgery, while subsequent long-term imaging was symptom-driven. The overall cohort included 15 patients; serial venous imaging analysis was performed in the five patients for whom delayed symptoms prompted follow-up MRI, using the same venous segment on 1-mm-slice T2-weighted images in the corresponding anatomical plane. No definite residual CCM was identified on available early postoperative imaging, and preservation of the associated venous drainage structure was documented in all patients. Five patients developed delayed symptoms 1–4 years after surgery. Apparent venous diameter increased from 1.0 to 2.1 mm, 0.8 to 2.2 mm, 0.9 to 1.9 mm, 1.2 to 2.6 mm, and 1.3 to 3.0 mm, respectively. Four selected patients underwent stereotactic radiosurgery (SRS) and subsequently improved clinically. Post-SRS MRI was directly available in two patients and showed decreased apparent venous caliber. The untreated patient remained intermittently symptomatic. Delayed increased conspicuity and apparent enlargement of preserved CCM-associated venous drainage structures may occur in selected symptomatic patients after CCM surgery. This finding should be considered preliminary and hypothesis-generating. The present data do not establish causality, predictive value, a diagnostic threshold, or SRS efficacy. Prospective studies with standardized long-term imaging and dedicated venous assessment are required.