Hypertensive pontine microhemorrhage.

BACKGROUND AND PURPOSE This study investigated whether the topography of hypertensive pontine microhemorrhages (hPMHs) resembles that of larger primary pontine hemorrhages. METHODS Sixty-nine consecutive patients with small-vessel disease underwent imaging with gradient-echo MRI, and 27 patients with hPMH were detected. Lesion size and location along the rostrocaudal (longitudinal), lateral (coronal), and anteroposterior (sagittal) axes were determined. RESULTS A total of 52 hPMHs were identified in the 27 patients (mean, 1.93+/-2.4 per patient). The lesions showed a nonrandom distribution, with a propensity to occur in the middle pons in the rostrocaudal axis, posterior half of the basis pontis in the anteroposterior axis, and central subdivision within the lateral axis. The area of hPMH ranged from 1.3 to 19.0 mm2 (mean, 5.06+/-3.72 mm2). The size of hPMH did not vary as a function of lesion location. CONCLUSIONS Previous studies reported that primary pontine hemorrhages tend to occur in the middle pons and at the junction of basis pontis and tegmentum. Therefore, topographical correspondences between large and small pontine hemorrhages may provide evidence that the 2 lesions share some etiological basis. Further investigation may determine whether hPMHs portend future symptomatic primary pontine hemorrhages.