[Case of specific MRI T2* weighted image associated with bacterial endocarditis]

We report a case of multiple signal loss lesions detected by T2* weighted image associated with bacterial endocarditis. A 23 year-old woman, who had undergone surgical closure of ventricular septal defect at age 2, suffered headache and general fatigue after dental treatment. She was admitted to another institution, and examinations revealed bacterial endcarditis. She was transferred to our hospital, and underwent aortic valve replacement. After the valve replacement, CT revealed parenchymal hematoma in the left frontal lobe. CT angiography (CTA) and cerebral angiography (CAG) demonstrated an aneurysm at the distal branch of the left middle cerebral artery. T2* weighted image demonstrated multiple signal loss lesions, which were not revealed by CAG and CTA. We speculated that these signal loss lesions were thrombosed mycotic intracranial aneurysms. She underwent left frontotemporal craniotomy, and the aneurysm was resected. Mycotic aneurysms are rare neurovascular lesions but their mortality and morbidity are high, so careful follow-up examinations are required. T2* weighted image was useful to detect mycotic aneurysms and plan the surgical strategy.