A close association between brain lacuna infarction and renal surface irregularity

This study was undertaken to examine the association between brain lacunae examined by magnetic resonance imaging (MRI), and the severity of renal ischemia, evaluated by computed tomography (CT). We reviewed 114 cases, out of 1694 brain MRI studies and 2861 kidney CT studies undertaken between May 1994 and March 1996 in which both brain MRI and kidney CT were examined. Brain lacunae were defined as low intensity areas between 5 mm and 10 mm in diameter with the T1-weighted image. The severity of irregularity of the renal surface was classified as one of three grades: absent, mild, or severe. The prevalence of brain lacunae in cases with the renal surface irregularity classified as absent, mild, or severe was six of 45, 14 of 45, and 17 of 24, respectively. There was a highly significant relationship (P < .001) between the prevalence of brain lacunae and the severity of the renal surface irregularity. This relationship persisted, even when the subjects were restricted to include hypertensive patients > 60 years old. The irregularity of the renal surface is mainly caused by ischemia due to arteriosclerosis in the renal arteries. The results reported here suggest that brain lacuna infarcts are closely associated with renal ischemia, implicating a causative role of renal ischemia for brain lacunae.