A 71-year-old woman with pulmonary sequestration had iodine hypersensitivity. Diagnosis was made using computed tomography without contrast enhancement and magnetic resonance imaging. An anomalous artery arising from the descending thoracic aorta was clearly defined. Thus the diagnosis of pulmonary sequestration was confirmed before successful operation without angiography. This diagnostic procedure is safe, noninvasive and useful to detect the anomalous artery, especially in the patient with iodine hypersensitivity.