Brain capillary telangiectasia: MR imaging appearance and clinicohistopathologic findings.

PURPOSE: To demonstrate the clinical and magnetic resonance (MR) imaging findings of brain capillary telangiectasia and compare them with postmortem specimens.
MATERIALS AND METHODS: MR images obtained in and clinical histories of 18 adult patients with a presumed diagnosis of capillary telangiectasia examined within 3 years were retrospectively reviewed. All patients had undergone MR imaging with conventional T1- and T2-weighted spin-echo sequences and gadolinium-enhanced T1-weighted and susceptibility-sensitive gradient-echo (GRE) sequences. No biopsies had been performed. Fourteen patients had undergone clinical and MR imaging follow-up (median, 11 months). Postmortem tissues from three cases of histopathologically confirmed capillary telangiectasia were imaged.
RESULTS: All lesions were small, homogeneously enhancing, and hypo- to isointense on T1-weighted images and iso- to slightly hyperintense on proton-density- and T2-weighted images. None was hypointense on proton-density- or T2-weighted images. All lesions showed marked GRE signal loss. None had changed at follow-up. Two patients had multiple classic cerebral cavernous angiomas. The three specimens showed no abnormal susceptibility and contained no hemosiderin at tissue analysis.
CONCLUSION: Capillary telangiectasia has mild contrast material enhancement but is otherwise undetectable on conventional MR images. It lacks the "hemosiderin rim" of cavernous angioma and demonstrates increased susceptibility only on GRE images, likely owing to blood oxygen-level-dependent contrast. GRE is essential in diagnosing brain capillary telangiectasia, which could otherwise be misdiagnosed as neoplasia, subacute infarction, or demyelination.