Arterial spin labeling in patients with schizophrenia: a systematic review

Abstract

Background: Neuroimaging studies are an invaluable source of information about the physiopathology of schizophrenia. Arterial spin labeling (ASL) is a new magnetic resonance technique (MRI) that is able to effectively evaluate brain function without the use of radiation. Objective: To make a systematic review of studies using ASL to compare resting-state regional cerebral blood flow (rCBF) patterns in patients with schizophrenia and healthy controls. Methods: Original articles were searched for on PubMed, Scopus, Web of Science and PsycINFO electronic databases. The search terms used were 'arterial' , 'spin' , 'labeling' , and 'schizophrenia' . Only studies comparing resting-state rCBF were included, a qualitative synthesis was then performed. Results: Ten articles were included in the review among a total of 22. Decreased rCBF in schizophrenia patients was described in the anterior cingulate, cuneus, fusiform gyrus, frontal lobe, left middle frontal gyrus, inferior frontal gyrus, lingual gyrus, middle occipital gyrus, and parietal lobe. The putamen was the only region with increased rCBF in schizophrenia. Discussion: The evidence of the studies reviewed lends support to the concept of hipofrontality in schizophrenia. rCBF alterations were found in regions classically associated with schizophrenia. ASL seems to be valid, and reliable tool to assess schizophrenia.

Neuroimaging in Schizophrenia

“…Abnormal resting state brain activity has also been reported in a meta-analysis of studies using PET, fMRI and ASL and the authors identified hypoactivation in the ventromedial prefrontal cortex, left hippocampus, posterior cingulate cortex, precuneus, and hyperactivation in bilateral lingual gyrus of schizophrenic patients compared to controls 31 . Lastly, in a systematic review of ASL imaging in schizophrenia, the authors identified convergent reductions in cerebral blood flow in the frontal lobe, left middle frontal gyrus, inferior frontal gyrus, lingual gyrus, cuneus, middle occipital gyrus, fusiform gyrus, anterior cingulate and parietal lobe, with the putamen as the only region showing increased CBF in schizophrenia 32 . The same study also found inconsistent results for middle temporal, parahippocampal, precuneus and thalamic regions 32 .…”

“…Lastly, in a systematic review of ASL imaging in schizophrenia, the authors identified convergent reductions in cerebral blood flow in the frontal lobe, left middle frontal gyrus, inferior frontal gyrus, lingual gyrus, cuneus, middle occipital gyrus, fusiform gyrus, anterior cingulate and parietal lobe, with the putamen as the only region showing increased CBF in schizophrenia 32 . The same study also found inconsistent results for middle temporal, parahippocampal, precuneus and thalamic regions 32 . Taken together, functional imaging studies point towards altered metabolic or hemodynamic activity in frontal, cingulate, parietal and occipital brain regions with a few areas of hyperactivity, such as the putamen and sensorimotor regions, but more work is needed to determine the clinical implications of these observations.…”

Schizophrenia: A Narrative Review of Etiopathogenetic, Diagnostic and Treatment Aspects

“…Limitations in the imaging studies on schizophrenia are represented by the issue that most of them mainly recruited chronic patients and individuals taking antipsychotic treatment, therefore making it difficult to identify the time of the brain changes and the effect of the treatment exposure [ 146 , 147 ]. Functional neuroimaging studies have shown alterations in the brain metabolism and the blood flow in the frontal, cingulate, parietal, putamen, and sensorimotor regions [ 148 , 149 , 150 , 151 ]. Dopamine dysfunction has also been observed in schizophrenic patients.…”

Heritability of Cerebral Blood Flow and the Correlation to Schizophrenia Spectrum Disorders: A Pseudo-continuous Arterial Spin Labeling Twin Study

“…11,13 Pseudo-continuous arterial spin labeling (pCASL) is a noninvasive magnetic resonance (MR) technique that uses arterial water as a diffusible tracer to form CBF images with high spatial resolution. 18 Arterial spin labeling (ASL) studies in schizophrenia are generally small and with some variability in findings (reviewed in Guimarães et al 19 and Théberge 20 ). Nevertheless, frontal hypoperfusion at rest has been reported in several studies, [21][22][23][24][25][26][27] most frequently in the anterior cingulate cortex 21,26,27 and the medial frontal gyrus.…”