Radioanatomical study of a true tracheal bronchus using multidetector computed tomography.
OBJECTIVE
True tracheal bronchus (TTB) is a rare anomaly in which a lobar or segmental ectopic bronchus arises from the trachea. We examined the frequency and multidetector computed tomography (MDCT) appearances of TTB.


METHODS
We retrospectively analyzed 9781 chest MDCT examinations. In cases in which there was an abnormal bronchus suggesting TTB on axial CT images, the following imaging of the abnormal bronchi was undertaken: multiplanar reformation (MPR), multiprojection volume reconstruction (MPVR), volume rendering (VR), and virtual endoscopy (VE).


RESULTS
Of 9781 MDCT examinations, 30 TTBs were observed in 10 females and 20 males. The frequency of TTB was 0.21% among 4622 females, 0.39% among 5159 males (0.31 % in the overall patient population). TTBs arose from the right lateral wall of the trachea; 17 TTBs were of the displaced type and 13 of the supernumerary type. With the displaced type, all segments of the right upper lobe were supplied by the TTB in 8 patients, and the apical segment was supplied in 8 patients. With the supernumerary type, TTBs showed blind termination in 10 patients, and the TTB had a small lobule in 3 patients. All TTBs were clearly visualized on MPR, MPVR, VR, and VE.


CONCLUSIONS
TTB was identified by MDCT with an incidence of 0.31%.
Suzuki
Masayuki
M
Department of Quantum Medical Technology, Graduate School of Medical Science, Kanazawa University, Kodatsuno, Kanazawa, Japan. suzuki@mhs.mp.kanazawa-u.ac.jp
Matsui
Osamu
O
Kawashima
Hiroko
H
Takemura
Akihiro
A
Matsubara
Kosuke
K
Hayashi
Norio
N
Koda
Wataru
W
Shibata
Yoshihiro
Y
D000293:Adolescent; D000328:Adult; D000368:Aged; D001980:Bronchi / Q000002:abnormalities*; D001995:Bronchography; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000002:abnormalities*; D055815:Young Adult