Prevalence of the Accessory Cardiac Bronchus on Multidetector Computed Tomography: Evaluation and Proposed Classification.

Purpose: Accessory cardiac bronchus (ACB) is a very rare congenital anomaly and may cause some clinical complications, such as recurrent episodes of both infection and hemoptysis. The purpose of this study was to assess the multidetector computed tomography (MDCT) characteristics of ACB and to classify this anomaly according to the MDCT aspects.
Materials and Methods: The routine thoracic CT scans from 5790 patients were evaluated retrospectively. The prevalence, location, length, diameter, division angle, distance from the carina, and the type of ACB were evaluated.
Results: A total of 12 ACBs were identified, with a prevalence of 0.2%. All ACBs originated from the intermediate bronchus. The median largest diameter of the ACBs was 7.75 mm (range: 5.8 to 10.30 mm), the median length was 12.1 mm (range: 8.6 to 35 mm), the median division angle was 61 degrees (range: 42 to 93 degrees), and the median distance from the carina was 16.95 mm (range: 5.7 to 22.20 mm). Six cases (50%) had a blind extremity (type 1: diverticulum or stump type), 3 cases (25%) had a mutiloculated cystic change at the end (type 2: cystic type), and 3 cases (25%) had a ventilated lobulus demarcated by an anomalous fissure (type 3: ventilated type).
Conclusions: ACBs can be classified into 3 types according to their MDCT features. Recognition of ACB is important, as it is associated with clinical complications and is also salient in trauma cases.