Comparison of Two Normalization Structures in Brain Perfusion Tomography in the First Episode of Schizophrenia Using Commercial Software

Abstract

Objectives: Single photon emission computed tomography with Tc-99m hexamethylpropylenamine oxime provides information on brain perfusion distribution in psychiatric patients. The assessment of cerebral blood flow using different normalization structures could be diverse. Methods: Quantification programs may improve diagnosis, but adequate normalization structure must be selected. We compared regional brain perfusion in twelve brain regions associated with schizophrenia using two different normalization structures - whole brain and cerebellum - in antipsychotic drug- naive patients during the first episode of schizophrenia. Results: We analyzed 12 brain regions associated with schizophrenia in 50 patients with the first episode of schizophrenia. Z-scores for each entire region, as well as left and right Z-scores, were calculated based on an age-matched normal database. We chose two normalization structures for Z-score calculation, the whole brain and the cerebellum. Conclusion: Based on the results, we conclude that both normalization structures can be used. However, the highest Z-score matches were observed for the gyrus rectus, orbitofrontal region, inferior medial frontal gyrus, medial orbital gyrus, middle frontal gyrus, anterior cingulate gyrus, superior medial frontal gyrus, and caudate, while the lowest matches were found for the medial temporal region and thalamus.