PET and SPECT in whiplash syndrome: a new approach to a forgotten brain?

Whiplash associated disorders are a medicolegally controversialcondition becoming increasingly worrisome in the western world. Thisstudy was designed to evaluate perfusion and glucose metabolism inwhiplash brain. Using Tc-99m-bicisate (ECD) single photon emission computed tomography (SPECT) and F-18-fluorodeoxyglucose (FDG) PET,six clinically and neuropsychologically controlled patients (patientgroup) with whiplash syndrome and 12 normal controls (control group)were investigated. Standardised elliptical regions of interest (ROIs)were determined in three adjacent transaxial slices in the frontal,parietal, temporal, and parieto-occipital cortex, cerebellum, brainstem, basal ganglia, and thalamus. For PET, the glucose metabolic index(GMI; =ROI uptake/global uptake at the level of the basal ganglia) and,for SPECT, the perfusion index (PI; =ROI/global) were calculated. Inthe patient group there was significant hypometabolism andhypoperfusion in the parieto-occipital regions (on the right (R) andleft (L) side) compared with the control group: PET data: GMIparieto-occipital R: control 1.066 (0.081) (mean (SD)), patient 0.946 (0.065); P=0.0092, Mann Whitney. GMI parieto-occipital L: control 1.034 (0.051), patient 0.922 (0.073); p=0.0067. SPECT data: PIparieto-occipital R: control 1.262 (0.066), patient 1.102 (0.063);P=0.0039. PI parieto-occipital L: control 1.226 (0.095), patient 1.098 (0.075); P=0.0273. In some patients there was hypometabolism (>2 SD of control) in regions other than the parieto-occipital region. It ishypothesised that parieto-occipital hypometabolism may be caused byactivation of nociceptive afferent nerves from the upper cervical spine.