Leptomeningeal metastases: reduction in regional cerebral blood flow and cognitive impairment.

Twenty-six patients with recently diagnosed leptomeningeal metastases underwent multiple diagnostic procedures in order to assess possible cerebral parenchymal involvement. Pretreatment studies included detailed neurological examination, computed tomographic scan, electroencephalogram, neuropsychological assessment, psychiatric evaluation, and measurement of regional cerebral blood flow (rCBF) using the xenon 133 inhalation technique. At diagnosis 50% of the patients had symptoms and signs of cerebral dysfunction. Computed tomographic scanning and electroencephalography detected abnormalities in 42% and 58%, respectively. Scoring was abnormally low on at least three neuropsychological tests in 93% of the patients. The mean rCBF was reduced in 88% of patients by 16.1 +/- 2.5% (mean +/- SEM; range, 8 to 45%) compared with age-matched controls (p less than 0.001). rCBF was reduced and cognition was impaired in patients with or without overt cerebral manifestations. Neuropsychological testing and rCBF measurement may be helpful in early detection of cerebral dysfunction in patients with leptomeningeal metastases.