Crossed cerebellar diaschisis in intracarotid sodium amytal procedures: a SPECT study.

Eight patients with drug-resistant complex-partial seizures were subjected to left- and right-sided intracarotid sodium amytal (ISA) procedures during preoperative investigations for surgical treatment. Regional changes of cerebral and cerebellar blood flow during barbiturization were measured by [99mTc]-HMPAO-SPECT. Crossed cerebellar diaschisis (CCD) was observed in 13 out of 16 tests (81%) as well as ipsilateral cerebral hypoperfusion (87%). Thus CCD occurred more frequently in ISA procedures than in previously studied patients with cerebral infarctions and tumors. Since intracarotid injections of sodium amytal lead to hypoperfusion mainly in those areas of the brain that are supplied by the middle cerebral artery, functional suppression of these regions is supposed to be one of the main preconditions of CCD. Our findings suggest that CCD as demonstrated by the SPECT-technique is a common phenomenon in ISA procedures.