New MR Techniques Shows Blood Flows Differently through Brains of Schizophrenics

Researchers in Germany have used a magnetic resonance imaging (MRI) technique called continuous arterial spin labeling (CASL) to map cerebral blood flow patterns in schizophrenic patients quickly and without using radiation or contrast agents.

The researchers' findings were published in the online edition and July 2010 issue of the journal Radiology. "Arterial spin labeling is a powerful technique that can help reduce the cost and complexity of examinations,” said the study's lead author, Lukas Scheef, M.D., from the department of radiology at the University of Bonn (Germany). "It can also be more readily repeated than methods that involve the use of contrast agents and radiotracers.”

Schizophrenia is a chronic and severe brain disorder that affects approximately 2.4 million American adults, according to the U.S. National Institute of Mental Health (Bethesda, MD, USA). Symptoms can include hallucinations, delusions, disordered thinking, movement disorders, social withdrawal, and cognitive deficits.

In the study, conducted at the University Hospital of Bonn, researchers utilized CASL MRI to compare cerebral blood flow in 11 nonmedicated patients with schizophrenia and 25 healthy controls. The patient group included three women with a mean age of 36 years and eight men with a mean age of 32 years. The control group included 13 women (mean age, 29 years) and 12 men (mean age, 30 years).

The study's findings revealed that compared to the healthy controls, the schizophrenic patients had extensive areas of hypoperfusion, or lower blood flow than normal in the frontal lobes and frontal cortex, anterior and medial cingulate gyri, and parietal lobes. These regions are associated with a number of higher cognitive functions including planning, decision-making, judgment, and impulse control.

Hyperperfusion, or increased blood flow, was observed in the cerebellum, brainstem, and thalamus of the schizophrenic patients. "Our CASL study revealed patterns of hypo- and hyper-perfusion similar to the perfusion patterns observed in positron emission tomography [PET] and single photon emission computed tomography [SPECT] studies of schizophrenic patients,” Dr. Scheef said.

Unlike PET and SPECT scanning, CASL MR images can be rapidly acquired without the use of ionizing radiation or contrast agents. In CASL MRI, arterial blood water is magnetically labeled in order to measure cerebral blood flow noninvasively. "CASL MRI may allow researchers to gain a better understanding of schizophrenia,” Dr. Scheef concluded. "In the long run, it may help to individualize and optimize treatment.”

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