A COMPARATIVE-STUDY OF I-123 IMP SPET AND CT IN THE INVESTIGATION OF CHRONIC-STAGE HEAD TRAUMA PATIENTS

The aims of this study were (1) to compare N-isopropyl-p-[I-123] iodoa mphetamine (I-123-IMP) SPET with computed tomography (CT) in chronic-s tage head trauma patients with neurological abnormalities and (2) to q uantify regional cerebral blood flow (rCBF) in patients with chronic-s tage head trauma. I-123-IMP SPET and CT were performed in 23 patients with chronic-stage head trauma and 12 normal controls. Both types of i maging were evaluated visually. In addition for the SPET images, the r CBF in 12 regions (bilateral frontal cortex, temporal cortex, parietal cortex, occipital cortex, perilolandic area, cerebellum: total 276 re gions) was analysed quantitatively using a reference sampling method. In total, 39 focal lesions related to neurological abnormalities were detected. Athough 22 (56.4%) lesions were observed using both CT and S PET, another 17 (43.6%) were detected by SPET only. The mean rCBF in t he localized lesions of each lobe, which correspond to low-density are as (LDAs), were lower on CT than those of each lobe seen only on SPET. These rCBF values were lower than the mean rCBF values in the lobes o f the controls. The mean rCBF values in each lobe with visually normal tracer uptakes were also significantly lower in the 23 patients than in the controls. I-123-IMP SPET is useful for demonstrating brain dysf unction in morphologically intact brain regions and for providing obje ctive evidence to account for the clinical presentation of patients pr esenting with chronic traumatic brain injury.