Intralobar pulmonary sequestration and anomalous systemic arterial supply to the basal segment of the lung: A comparative study of clinical features and 3D imaging.

BACKGROUND: Intralobar pulmonary sequestration (IPS) and anomalous systemic arterial supply to the basal segment of the lung (ABL) are rare congenital anomalies in which a portion of the lung receives its blood supply from a systemic artery. IPS has abnormal bronchial and alveolar structures, whereas ABL does not. We compared the clinical characteristics and management of IPS and ABL, referencing the role of three-dimensional (3D) bronchial imaging. METHODS: We retrospectively reviewed patients diagnosed with IPS or ABL at two Japanese hospitals between January 2007 and September 2024. We collected data on clinical characteristics, diagnostic approaches, and management strategies. 3D bronchial imaging reconstructed from computed tomography (CT) data was graded as "highly useful," "useful," or "not useful" for identifying bronchial abnormalities. RESULTS: Twenty-five patients (IPS, n = 19; ABL, n = 6) were enrolled. Respiratory infections tended to be more common in the IPS group (p = 0.35), and hemoptysis in the ABL group (p = 0.06). The mean diameter of the abnormal vessels in the ABL group was significantly larger than that in the IPS group (p < 0.01). Surgery was performed in 12 IPS and five ABL cases, while seven patients were followed conservatively without symptom progression over 6.8 years. 3D imaging is particularly useful with thin-slice CT, but is limited by slice thickness, lesion size, or reduced lung volume. CONCLUSIONS: IPS and ABL exhibit distinct features that influence management strategies. Larger abnormal vessels in ABL may be associated with an increased risk of hemoptysis. 3D bronchial imaging enhances diagnostic confidence and aids in differentiating between these diseases.