Anomalous Systemic Artery to the Non-Sequestrated Lung: Multi-Slice Computed Tomography Features
Anomalous systemic artery to the non-sequestrated lung (ASANSL) is a rare congenital anomaly that was previously classified as a Pryce type I sequestration. This condition involves an anomalous systemic artery (ASA) supplying blood to a normal lung. Historically, Pryce described three variants of sequestration: an abnormal artery confined to a normally connected lung, an abnormal artery supplying both a sequestered mass and adjacent normal lung, and an abnormal artery to the sequestered mass. ASANSL falls under the first category, where the anomalous artery supplies a lung with normal bronchial connections.
To better understand the characteristics of ASANSL, a retrospective study was conducted on 15 patients who underwent contrast-enhanced multi-slice computed tomography (MSCT). The findings revealed that all cases involved an ASA originating from the descending aorta, with normal bronchial connections. In 13 out of 15 cases, the ASA supplied the left lower lung (LLL), while the remaining two cases involved the right lower lobe (RLL). Specifically, 12 cases showed the ASA supplying all basal segments of the LLL, and three cases involved only part of the segments of the LLL or RLL. Additionally, various abnormalities in the pulmonary parenchyma were observed in the involved segments, including atelectasis, emphysema, bronchiectasis, and areas of ground-glass opacity. These changes are indicative of slight pulmonary congestion caused by the high systemic arterial pressure.
The study also highlighted the diagnostic utility of MSCT in identifying ASANSL. MSCT provides detailed images of the bronchial and parenchymal structures, as well as the vascular anatomy of the lung. This non-invasive imaging technique has become the most useful diagnostic method for evaluating patients suspected of having ASANSL, replacing the need for angiography in most cases. The ability of MSCT to accurately depict the vascular anomalies and associated parenchymal changes makes it an invaluable tool for both diagnosis and treatment planning.
Treatment options for ASANSL vary depending on the severity of the condition and the patient’s clinical presentation. In the study, five patients underwent surgical treatment, which involved the division of the ASA followed by lobectomy. One patient opted for therapeutic embolization of the ASA, while nine patients chose to undergo follow-up without immediate intervention. Other treatment modalities described in the literature include ligation or division of the ASA, resection of the diseased lung segments, and re-implantation of the ASA to the pulmonary artery. The choice of treatment is influenced by factors such as the extent of the vascular anomaly, the presence of parenchymal abnormalities, and the patient’s overall health.
The nomenclature surrounding ASANSL has been a source of confusion, with various terms used to describe the condition, including “ASA to the left lower lobe,” “ASA supply to the normal basal segments of LLL,” and “pseudosequestration.” The authors of the study suggest that ASANSL may be the most accurate term to describe this anomaly. While the majority of cases in the study involved the basal segments of the LLL, there were instances where only part of the LLL or RLL segments were affected. This variability underscores the importance of using a term that encompasses the full spectrum of the condition, rather than one that is limited to a specific anatomical location.
In conclusion, ASANSL is a rare congenital anomaly that can be effectively diagnosed using MSCT. This imaging technique provides detailed information about the vascular and parenchymal structures of the lung, aiding in the identification of the anomalous artery and any associated abnormalities. The study emphasizes the importance of accurate diagnosis and appropriate treatment planning, which may include surgical intervention, embolization, or follow-up. The term ASANSL is proposed as the most accurate descriptor for this condition, reflecting its diverse anatomical presentations. MSCT continues to be a valuable tool in the evaluation and management of patients with ASANSL, offering a non-invasive and reliable method for diagnosis and treatment planning.
doi.org/10.1097/CM9.0000000000000965
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