The use of vessel wall imaging to detect a de novo microaneurysm on the periventricular anastomoses in moyamoya disease: illustrative case.

backgroundMoyamoya disease (MMD) is linked to the formation of intracranial aneurysms. The authors recently observed an effective use of magnetic resonance vessel wall imaging (MR-VWI) to detect de novo unruptured MMD-associated microaneurysms. OBSERVATIONS: The authors describe a 57-year-old female who was diagnosed with MMD 6 years ago after suffering a left putaminal hemorrhage. MR-VWI revealed point-like enhancement in the right posterior paraventricular region during the annual follow-up. On the T2-weighted image, this lesion was surrounded by high intensity. Angiography revealed a microaneurysm in the periventricular anastomosis. Right combined revascularization surgery was performed to prevent future hemorrhagic events. Another de novo circumferential enhanced lesion on MR-VWI appeared in the left posterior periventricular region 3 months after surgery. Angiography revealed that the enhanced lesion was a de novo microaneurysm on the periventricular anastomosis. The left combined revascularization surgery went well. The bilateral microaneurysms vanished on follow-up angiography. LESSONS: Unruptured MMD-associated microaneurysms on the periventricular anastomosis can be detected using MR-VWI. Revascularization surgery can eliminate microaneurysms by reducing hemodynamic stress on the periventricular anastomosis.