researchers in germany have used a magnetic 1 imaging (mri核磁共振成像) technique called continuous arterial spin labeling (casl) to map 2（大脑的） blood flow patterns in schizophrenic（精神分裂症的） patients quickly and without using radiation or contrast agents（对比剂，造影剂） . their findings appear in the online edition and july printed issue of the journal radiology. "arterial spin labeling is a powerful technique that can help reduce the cost and 3 of examinations," said the study's lead author, lukas scheef, m.d., from the department of radiology at university of bonn, germany. "it can also be more readily repeated than methods that involve the use of contrast agents and radiotracers（放射示踪物） ."
schizophrenia is a 4 and severe brain 5 that affects approximately 2.4 million american adults, according to the national institute of mental health. symptoms can include hallucinations（幻觉） , 6（妄想，错觉） , disordered thinking, movement 7, social 8 and 9 10.
in the study, conducted at the university hospital of bonn in germany, researchers used casl mri to compare cerebral blood flow in 11 non-medicated 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 results revealed that compared to the healthy controls, the schizophrenic patients had extensive areas of hypoperfusion, or lower blood flow than normal in the frontal 11（大脑前庭） and frontal cortex（皮质） , 12（前面的） and medial cingulate（有色带的） gyri（脑回） , and parietal lobes（顶叶） . these regions are associated with a number of higher cognitive functions including planning, decision making, 13 and impulse control.
hyperperfusion, or increased blood flow, was observed in the cerebellum（小脑） , brainstem（脑干） and thalamus（丘脑） of the schizophrenic patients.
"our casl study revealed patterns of hypo- and hyperperfusion similar to the perfusion（充满） patterns observed in positron 14 tomography (pet) and single photon emission 15 tomography (spect单光子发射计算机化断层显像) studies of schizophrenic patients," dr. scheef said.
unlike pet and spect studies, casl mr images can be quickly acquired without the use of ionizing radiation（电离辐射） or contrast agents. in casl mri, arterial blood water is magnetically labeled in order to non-invasively measure cerebral blood flow.
"casl mri may allow researchers to gain a better understanding of schizophrenia," dr. scheef said. "in the long run, it may help to individualize and 16 treatment."
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