Systemic arterial supply to the normal basal segments of the left lower lobe: radiographic and CT findings in 11 patients.

SUMMARY: To assess the radiologic findings of systemic arterial supply to the normal basal segments of the left lower lobe, chest radiographs and CT scans of all 11 patients were reviewed retrospectively by two chest radiologists. On posteroanterior chest radiographs (n = 11), the anomalous systemic artery arising from the descending thoracic aorta was shown as a retrocardiac mass (n = 11). Absence of normal lower lobar pulmonary artery shadow (n = 11), partial obliteration of the descending aortic interface (n = 9), and increased interstitial markings in left lower lung zone (n = 8) were also noted. On contrast-enhanced scans (n = 11), abrupt tapering of the normal left lower lobar pulmonary artery distal to the origin of superior segmental artery (n = 11), aberrant systemic artery originating from the descending aorta (n = 11), mild volume loss in the left lower lobe (n = 11), diffuse dilatation of the intrapulmonary peripheral vasculature (n = 11) and areas of ground-glass opacity (n = 10) in the basal segments of the left lower lobe were seen. Because chest radiography and CT consistently demonstrate several combinations of characteristic findings, conventional aortography may not be necessary for proper diagnosis of this anomaly.