Background: Bronchial situs defines the position of the cardiac atria, lungs, liver, stomach, and spleen relative to the midline. Bronchial situs anomalies (BSA) are classified as situs inversus and situs ambiguus (right isomerism and left isomerism). The aim of our study is to evaluate the relationship between BSA and its subtypes and lung parenchymal findings.

Materials and Methods: By retrospectively scanning the archives of our hospital between 2010 and 2022, 31 patients in the 0-18 age group who were diagnosed with BSA in thorax CT angiography examination were identified. The BSA type of 31 patients was grouped as situs inversus, right isomerism, and left isomerism. The lung parenchyma was divided into two categories as "presence of a finding" and "no finding". The lung parenchymal findings of the patients were classified as "mosaic perfusion", "consolidation", "ground glass density", "peribronchial thickening", "subsegmental atelectasis", and "other". Chi-square test was used in statistical analysis. A P value of <0.05 was considered significant.

Results: The ages of 31 pediatric patients were between 0-84 months (mean: 13.03 ± 22.04). The distribution of 31 patients was situs inversus n=7 (22.5%), right isomerism n=13 (41.9%), left isomerism n=11 (35.4%). There were 10 patients (32.2%) without findings in the lung parenchyma and 21 patients (67.7%) with findings. Lung parenchymal findings; mosaic perfusion (n=21), consolidation (n=9), ground glass density (n=9), peribronchial thickening (n=7), subsegmental atelectasis (n=6), other=3 (millimetric calcific nodule n=1 , interlobular septal thickening n=1, air cyst n=1). When the relationship between BSA type and findings in the lung parenchyma was evaluated, a significant relationship was found between situs inversus (p = 0.012) and right isomerism (p = 0.004). There were no findings in 5 of 7 patients with situs inversus (71.4%). All 11 patients with right isomerism had parenchymal findings. Significant relationships were detected between both situs inversus and right isomerism and mosaic perfusion (p=0.012, p=0.004, respectively).

Discussion and Conclusion: According to our study, a significant relationship was found between BSA types and findings in the lung parenchyma. While parenchymal findings were less common in situs inversus, parenchymal findings were more common in right isomerism. While situs inversus,

one of the BSA types, has a more benign course, the frequency of other organ anomalies (especially congenital heart diseases) accompanying situs ambiguus may be related to this conditions.