The right-sided double lumen endobronchial tube (R-DLT) is seldom. The principal cause of reticence for using the R-DLT are the difficult positioning of its lateral orifice in front of the origin of the right upper lobe (RUL) and the variability of the length of the right main stem bronchus (RMSB). Both the angle between the right upper lobe (RUL) bronchus origin and the RMSB and the length of the RMSB can be measured with high resolution CT-scan. These measures can be useful in clinical practice as they help to determine when a R-DLT should not be used or used with caution when facing a large variation of the angle of the RUL or a proximal implantation of a RUL bronchus .

Since the introduction in the early '80s of the disposable double-lumen endobronchial tube (DLT), combined with the use of fiberoptic bronchoscopy (FOB) to confirm its positioning, some controversies have aroused; the main concern being the use of the right-sided double-lumen endobronchial tube (R-DLT). Alongside this persistent controversy, the anatomy of the right tracheo-bronchial tree seems to be the principal cause of reticence for using the R-DLT. Compared to the left main stem bronchus, this anatomy is relatively complex and can be divided in two issues: 1) the variable length of the right main-stem bronchus (RMSB) and consequently, the variable level of insertion of the right upper lobe (RUL) bronchus on the lateral part of the RMSB and 2) the alignment of the lateral orifice of the R-DLT in regard of the RUL bronchus origin. A as part of an extensive study of the tracheo-bronchial tree anatomy with high resolution CT-scan, we had the opportunity to measure differently the length of the main stem right bronchus and the angulation between the RUL bronchus origin and the lateral aspect of the right side main stem bronchus.

Inclusion Criteria:

• Aged 35 to 85 years old

Exclusion Criteria:

• Unavailable weight and height
• Tracheobronchial tree pathologies (e.g. : tracheomalacia, tracheobronchomegaly, endobronchial lesions, bronchiectasis, etc.)
• Mediastinal pathologies inducing an extrinsic compression of the tracheobronchial tree.
• Pulmonary pathologies inducing a deformation of the tracheobronchial tree (e.g.: retraction, important atelectasis, pulmonary fibrosis, chronic tuberculosis, etc.)
• Patients that have had a treatment or surgery inducing a deformation of the tracheobronchial tree (e.g.: lobectomy, pneumonectomy, radiotherapy)
• An important musculoskeletal deformity at the thoracic level
• Low-quality CT scan exams (e.g.: significant kinetic artifacts where measurements should be taken

Evaluation of radiological consecutives thoracic CT-Scan reconstruction in a tertiary university hearth and lung institute. Patients had CT- scan for diagnosis or follow-up purposes