Lung perfusion impairments in pulmonary embolic and airway obstruction with noncontrast MR imaging. |
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Authors: | Kazuyoshi Suga Nobuhiko Ogasawara Munemasa Okada Toshinobu Tsukuda Naofumi Matsunaga Mitsue Miyazaki |
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Affiliation: | Department of Radiology, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan. sugar@po.cc.yamaguchi-u.ac.jp |
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Abstract: | A noncontrast electrocardiography (ECG)-gated, fast-spin-echo magnetic resonance imaging was applied to noninvasively define perfusion impairments in pulmonary embolic and airway obstruction dog models. Two-phase ECG-gated lung images of the minimal lung signal intensity during systole and maximal signal intensity during diastole were acquired by using optimized R-wave triggering delay times in seven dogs anesthetized with pentobarbital sodium before, soon after, and 2 mo after embolization with enbucrilate and in another eight dogs before and after bronchial occlusion with balloon catheters, in combination with a gadolinium diethylenetriaminepentaacetic acid-enhanced dynamic study. An ECG-gated subtraction image between the two-phase lung images provided a uniform but gravity-dependent perfusion map in normal lungs. Furthermore, it defined all 13 variable-size perfusion deficits associated with pulmonary embolism and the dynamically decreased perfusion with time after bronchial occlusion in all the airway obstruction models. These results were consistent with contrast-enhanced pulmonary arterial perfusion phase images. This noncontrast imaging could be equivalent to a contrast-enhanced dynamic study in the definition of regionally impaired pulmonary arterial perfusion in pulmonary embolism and airway obstruction. |
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