BACKGROUND: The aim of the study was to compare SPECT and CT scanning results in patients after mild head trauma, the former in the aspect of both focal and regional perfusion deficits.
METHODS: High-resolution ^99mTc-HMPAO SPECT was performed on a group of 31 patients after mild head trauma using a three-head gammacamera, qualitatively and quantitatively, utilising an asymmetry index for unilateral perfusion deficits and a comparison to cerebellar perfusion for assessing the regional cerebral perfusion. For assessing the normal values a control group of 30 patients was studied.
RESULTS: 27 studies were abnormal, 4 normal. Abnormalities consisted of focal perfusion deficits in 27 patients and diffuse regional hypoperfusion in 11 patients. Focal perfusion deficits were localised most frequently in frontal lobes and occipito-parietal area. Analysing individual cases, diffuse regional hypoperfusion was most pronounced in frontal lobes, analysing whole group a significant decrease of regional cerebral perfusion was found in all brain regions: frontal, occipital, parietal lobes, basal ganglia and thalami, except temporal lobes. A separate entity presents 4 patients in whom careful investigation revealed simulation of head trauma. In those cases perfusion brain SPECT was normal. CT scanning showed abnormalities in brain parenchyma in 11 patients, in bone in 9 patients. 11 patients showed persistent neurological symptoms and signs. Correlation between SPECT results and those signs was high in 7 of them, partial in 3, no correlation was seen in 2.
CONCLUSIONS: Brain perfusion SPECT is a useful tool in the assessing of patients after mild head trauma. It shows higher sensitivity than brain CT, although it may lack specificity in some cases. SPECT shows high utility in discriminating cases of simulation. It may be a useful tool in forensic medicine.