Resting-State Perfusion in Nonmedicated Schizophrenic Patients: A Continuous Arterial Spin-labeling 3.0-T MR Study

Abstract

CASL in schizophrenia revealed patterns of hypo- and hyperperfusion similar to the perfusion patterns in previously published positron emission tomographic and single photon emission computed tomographic studies. The advantages of CASL, including independence from injected contrast agents, no irradiation, and fast acquisition time, may facilitate intensive perfusion studies of the early recognition of schizophrenia and other psychiatric disorders, as well as longitudinal disease-monitoring research of these conditions.

Increased resting perfusion of the hippocampus in high positive schizotypy: A pseudocontinuous arterial spin labeling study

“…Overall, these studies reported seemingly mixed results, including increases (Friston, Liddle, Frith, Hirsch, & Frackowiak, 1992; Liddle et al, 1992; Malaspina et al, 2004; Pinkham et al, 2011; Schobel et al, 2013, 2009; Talati et al, 2014; Talati, Rane, Skinner, Gore, & Heckers, 2015), decreases (Kindler et al, 2015; Nordahl et al, 1996; Scheef et al, 2010; Tamminga et al, 1992), or no differences (Horn et al, 2009; Ota et al, 2014; Vita et al, 1995). Beyond the hippocampus, other brain regions of significantly elevated resting perfusion in schizophrenia patients compared with healthy controls have involved the basal ganglia and middle temporal lobes (Pinkham et al, 2011), cerebellum, brainstem, and thalamus (Scheef et al, 2010). Noteworthy, while not directly focusing on the hippocampus as a specific region, initial PET and SPECT studies did not find increased perfusion in medial temporal regions (Andreasen et al, 1997; Catafau et al, 1994; Early, Reiman, Raichle, & Spitznagel, 1987; Parellada et al, 1994).…”

Arterial spin labeling in patients with schizophrenia: a systematic review

“…Impaired parahippocampal recruitment during visual-memory encoding has been reported in patients and their siblings 37 . In our review, two small studies with the same sample size found divergent results in this region: while Scheef et al 14 (N = 11) described increased rCBF in this brain region, Walther et al 35 (N = 11) found precisely the opposite. Again, evidence is not enough to determine the rCBF patterns in the parahippocampus of patients with schizophrenia.…”

“…Of note, most of the divergent findings were described in the same study, by Scheef et al 14 (see Table 3 for details). putamen is in line with the results of studies using other neuroimaging methods and is probably a consequence of antipsychotic use 30 .…”

“…Studies have shown that functions mediated by the precuneus are impaired in schizophrenia 39 . Scheef et al 14 (N = 11) reported increased rCBF in the precuneus of patients, which is in contrast with Pinkham et al 17 (N = 30). The divergent data available make it impossible to determine rCBF patterns in the precuneus of patients with schizophrenia.…”

“…However, it is not yet clear whether rCBF in this region is increased or decreased in patients 6 . Among the articles included in our review, Pinkham et al 17 (N = 30) reported increased rCBF in the right MTG in schizophrenia, whereas Scheef et al 14 (N = 11), the only study with unmedicated patients, found decreased rCBF in patients relative to controls. The assumption of an antipsychotic effect to explain these differences is tempting, but the answer remains elusive.…”