Capillary telangiectasias of the pons. Does diffusion-weighted MR increase diagnostic accuracy?

Abstract

Background and purpose: Capillary telangiectasias are benign lesions of the brainstem which are sometimes difficult to distinguish from other lesions in standard MRI. The purpose of this study was to evaluate if diffusion-weighted imaging (DWI) could help to improve diagnostic accuracy.

Methods: 148 MR examinations of patients with pontine lesions were evaluated retrospectively and revealed capillary telangiectasia (n=18), presumed microvascular disease (n=20), encephalitis disseminata (n=21), pontine myelinolysis (n=16), tumor (n=20), acute infarction (n=20), subacute infarction (n=13) and chronic infarction (n=20). All patients were examined using identical measurement parameters for DWI, Fluid attenuated inversion recovery, T2-weighted turbo spin-echo, and T1-weighted spin-echo before and after application of contrast agent in transverse orientation.

Results: All capillary telangiectasias showed low signal intensity in DWI and significant contrast enhancement after application of gadolinium. Hypointense signal on DWI was very rare for the remaining lesions: only 1 pontine myelinolysis, 1 tumor, 4 subacute infarctions, and 19 chronic infarctions also revealed low signal intensity on DWI. The combination of high signal intensity on T1-weighted post-contrast images and low signal intensity on DWI was found for all capillary telangiectasias, but only for 1/20 tumor and for 4/13 subacute infarctions. These lesions could be differentiated by their clinical course and/or MRI follow-up examinations. The results of the visual assessment were confirmed by quantitative evaluation.

Conclusion: DWI seems to be a useful adjunct for the diagnosis of capillary telangiectasias which will facilitate the differential diagnosis concerning tumorous, inflammatory and ischemic lesions.