Role of 123I-IMP SPET in the early diagnosis of borderline chronic hydrocephalus after aneurysmal subarachnoid haemorrhage.

摘要

Chronic hydrocephalus after aneurysmal sub-arachnoid haemorrhage (SAH) is easily diagnosed in most cases. However, the diagnosis is sometimes difficult in borderline cases, in which (a) pathognomonic clinical deterioration due to hydrocephalus is masked by the neurological deficits caused in the acute stage of SAH and (b) ventricular enlargement is not so marked on CT scan. The purpose of this study was to investigate whether or not iodine-123 labelled N-isopropyl-p-iodo-amphetamine (123I-IMP) single-photon emission tomography (SPET) is of value for the early diagnosis of borderline chronic hydrocephalus after SAH. Fifteen patients who met the criteria of borderline chronic hydrocephalus were selected for the study, and underwent a shunt operation. The patients were divided into a shunt-effective group and a shunt-ineffective group according to neurological improvement after the shunt operation. 123I-IMP SPET was performed in the acute stage of SAH, within 1 week before the shunt operation, and 2 weeks after the shunt operation. Regional cerebral blood flow was estimated by the 123I-IMP autoradiographic method. Pre-shunting periventricular low-perfusion areas showed statistically significant differences between the two groups (P<0.05). In the shunt-effective group, peri-ventricular low-perfusion areas on pre-shunting SPET were significantly enlarged compared with those in the acute stage of SAH (P<0.05), and they were significantly reduced after the shunt operation (P<0.05). In the shunt-ineffective group, periventricular low-perfusion areas showed no significant changes during the course. These results suggest that periventricular low-perfusion areas enlarge in the early stage of chronic hydrocephalus after SAH, and that 123I-IMP SPET can be used for both the early diagnosis of borderline chronic hydrocephalus after SAH and the prediction of shunt effectiveness.