ABSTRACT
<p><b>OBJECTIVE</b>To investigate the characteristic findings of an anomalous systemic arterial supply to the lung without the pulmonary artery on spiral CT and discuss its nomenclature.</p><p><b>METHODS</b>Four cases of anomalous systemic arterial supply to the left basal segment of the lung without the pulmonary artery were retrospectively reviewed with analysis of the characteristic CT findings.</p><p><b>RESULTS</b>On spiral CT scans, the involved left lower lung including the entire left basal segments (n=2), the lateral and posterior basal segment (n=1), and the anterior, medial, and posterior basal segment (n=1) had mild volume loss and areas of ground-glass opacity but with normal bronchial trees. The absence of the entire or part of the basal segments of the normal left lower lobar pulmonary artery, anomalous systemic artery originating from the abdominal aorta, diffuse dilatation of the systemic arterial branches distributed in the basal segments of the left lower lobe, and left lower pulmonary venous drainage into left atrium were found in all these patients.</p><p><b>CONCLUSION</b>This anomaly presents with characteristic findings on chest spiral CT, for which the nomenclature of local absent pulmonary artery better shows the characteristics of the disease.</p>