Reproducibility of phase rotation stimulated echo acquisition mode at 3T in schizophrenia: Emphasis on glutamine.

PURPOSE: To determine the reproducibility and reliability of glutamine (Gln), measured with a very short echo time phase rotation stimulated echo acquisition mode (VTE-PR STEAM) sequence at 3T, in subjects with schizophrenia. METHODS: Seven subjects with schizophrenia were scanned twice with VTE-PR STEAM in a Siemens 3T TIM Trio scanner with a 32-channel head coil. Spectroscopic data were collected from two voxels in gray matter, one in the dorsal anterior cingulate and the other in the medial occipital cortex. Reproducibility was assessed using coefficients of variation (CVs) and reliability with standard error of measurement and intraclass correlations (ICCs). Phantoms containing increasing concentrations of Gln in a physiologic solution of other neurometabolites with overlapping resonances were scanned to assess the validity of spectral Gln measurement. RESULTS: Very good reliability and reproducibility for Gln in both regions of interest were supported by CVs of ≤10.0% and ICCs of ≥0.6, respectively. Phantom studies documented a robust correspondence between known Gln concentrations and VTE-PR STEAM measurements of this metabolite (R(2) = 0.988). CONCLUSION: The VTE-PR STEAM approach at 3T permits the longitudinal assessment of Gln and other (1) H MR spectroscopy neurometabolites in a clinically plausible setting.

A review of longitudinal electroconvulsive therapy: neuroimaging investigations.

Electroconvulsive therapy (ECT) is the most effective treatment for a depressive episode but the mechanism of action and neural correlates of response are poorly understood. Different theories have suggested that anticonvulsant properties or neurotrophic effects are related to the unique mechanism of action of ECT. This review assessed longitudinal imaging investigations (both structural and functional) associated with ECT response published from 2002 to August 2013. We identified 26 investigations that used a variety of different imaging modalities and data analysis methods. Despite these methodological differences, we summarized the major findings of each investigation and identified common patterns that exist across multiple investigations. The ECT response is associated with decreased frontal perfusion, metabolism, and functional connectivity and increased volume and neuronal chemical metabolites. The general collective of longitudinal neuroimaging investigations support both the anticonvulsant and the neurotrophic effects of ECT. We propose a conceptual framework that integrates these seemingly contradictory hypotheses.