Gray matter (GM) volume deficits have been described in patients with schizophrenia (Sz) and bipolar disorder (BD), but to date, few studies have directly compared GM volumes between these syndromes with methods allowing for whole-brain comparisons. We have used structural magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) to compare GM volumes between 38 Sz and 19 BD chronic patients. We also included 24 healthy controls. The results revealed a widespread cortical (dorsolateral and medial prefrontal and precentral) and cerebellar deficit as well as GM deficits in putamen and thalamus in Sz when compared to BD patients. Besides, a subcortical GM deficit was shown by Sz and BD groups when compared to the healthy controls, although a putaminal reduction was only evident in the Sz patients. In this comparison, the BD patients showed a limited cortical and subcortical GM deficit. These results support a partly different pattern of GM deficits associated to chronic Sz and chronic BD, with some degree of overlapping.

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The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose.

Aims:The aim of this study was to assess the relation between cognition, gray matter (GM) volumes and gamma noise power (amount of background oscillatory activity in the gamma band) in schizophrenia. Methods:We explored the relation between cognitive performance and regional GM volumes using voxel-based morphometry (VBM), in order to discover if the association between gamma noise power (an electroencephalography measurement of background activity in the gamma band) and cognition is observed through structural deficits related to the disease. Noise power, magnetic resonance imaging and cognitive assessments were obtained in 17 drug-free paranoid patients with schizophrenia and 13 healthy controls.Results: In comparison with controls, patients showed GM deficits at posterior cingulate (bilateral), left inferior parietal (supramarginal gyrus) and left inferior dorsolateral prefrontal regions. Patients exhibited a direct association between performance in working memory and right temporal (superior and inferior gyri) GM densities. They also displayed a negative association between right anterior cerebellum volume and gamma noise power at the frontal midline (Fz) site. Conclusion:A structural deficit in the cerebellum may be involved in gamma activity disorganization in schizophrenia. Temporal structural deficits may relate to cognitive dysfunction in this illness.