PONTINE ISCHEMIC RAREFACTION

To investigate apparently asymptomatic, bilateral symmetrical predomin antly pontine hyperintensities (PHI) on magnetic resonance imaging (MR I) scans in elderly patients, we examined the pens histopathologically in two brains of elderly hypertensives with PHI, and in three without PHI, on postmortem MRI scans. We also reviewed 85 serial in vivo MRI scans of patients over 60 and compared scan findings, vascular risk fa ctors, and clinical symptoms between patients with PHI and a control g roup. A subcortical arteriosclerotic encephalopathy (SAE)-like patholo gy was present in the pens in only the two autopsy brains with PHI and corresponded with the location of PHI on the postmortem MRI scans and with the most frequent sites of PHI on in vivo scans. SAE also involv ed the hemispheric white matter in one of the autopsy brains. Five of 16 (31%) patients with, and 4 of 69 (6%) without, PHI on in vivo MRI s cans had marked periventricular hyperintensity (PVHI) compatible with SAE (p = 0.01). We conclude that an SAE-like pathology may be seen in the pens in elderly hypertensives and this pathology is probably the c ause of PHI seen on MRI scans of patients over 60 years of age.