CROSSED CEREBELLAR DIASCHISIS ASSOCIATED WITH BALLOON TEST OCCLUSION OF THE CAROTID-ARTERY

Tc-99(m)-hexamethylpropyleneamine oxime (Tc-99(m)-HMPAO) single photon emission computed tomographic (SPECT) brain imaging performed in conj unction with balloon test occlusion of the carotid artery has been use d to assess risk of neurologic sequelae that might follow permanent su rgical ligation of the artery. The predictive value of cortical hypope rfusion during temporary carotid occlusion for adverse neurologic even ts has been debated in previous publications. We believe that the risk of an adverse event is greater when a reduction in cortical perfusion during balloon test occlusion is associated with crossed cerebellar d iaschisis (CCD). To test our hypothesis we evaluated the results of 27 Tc-99(m)HMPAO SPECT brain studies obtained in association with balloo n test occlusions of the carotid artery. In each case we correlated cl inical outcome with the presence or absence of regional decreases in c erebral perfusion and CCD. All of the 27 patients were free of neurolo gic symptoms during the balloon test occlusion. Seventeen of the 27 sc intigraphic studies were felt to be abnormal, showing cortical perfusi on defects all on the side of the occlusion. Among these 17 patients, five demonstrated CCD. Four of these five CCD patients showed evidence for cerebral cortical ischaemia on the side of the temporary carotid occlusion either shortly after the procedure or following carotid arte ry sacrifice. Of the remaining 12 patients with regionally reduced cer ebral perfusion and no CCD, none showed evidence for cortical ischaemi a in association with balloon test occlusion, and five of these 12 pat ients had carotid ligation without subsequent neurologic sequelae. Our results provide evidence to support our hypothesis that when CCD acco mpanies regional hypoperfusion on a brain SPECT study obtained after i njection of Tc-99(m)-HMPAO during balloon test occlusion of the caroti d artery, the patient is likely to be at increased risk of adverse neu rologic sequelae following carotid sacrifice.