Aims and objectives
Saber-Sheath-Trachea (SST) is a specific,
easy to recognize but often unreported,
sign of COPD .
It’s defined by a tracheal index (i.e.
ratio of coronal to sagittal diameter of tracheal lumen) <2/3 (or <0,67) [2-3].
We investigated the reliability of this sign as a marker of a specific COPD phenotype,
through the analysis of the association between the Tracheal-Index (TI) and the automatic CT-quantification (QCT) of emphysema and air-trapping.
Methods and materials
Data from patients who underwent inspiratory and expiratory volumetric CT scans of the chest and pulmonary function tests (PFT) in the same period (maximum range: 15 days) were retrospectively acquired to be analyzed.
Patients without spirometric evidence of COPD and patients with recent episode of exacerbation of COPD or with previous history of thoracic surgery,
tracheostomy and diseases or radiotherapic treatment of the mediastinum were excluded.
At the end 63 patients met...
SST was found in 18/63 patients (28,6%); 14 patients showed the maximum tracheal narrowing at a different point from the one conventionally used,
and 5 of these had SST.
Compared to those with a normal TI,
patients with SST had lower FEV1/FVC (p<0,001) and lower FEV1 (p=0,03),
while no significant differences were observed for FVC,
BMI and smoking history (TAB.
prevalence of SST was significantly higher in GOLD classes III-IV (38 patients / 15 SST / 39,5%) vs...
Our results confirm the inverse relationship between TI and the severity of air-flow obstruction,
and the role of Saber-Sheath-Trachea as a reliable and specific sign of COPD.
More specifically this sign seems to be a marker of a mixed-phenotype,
with both components of disease predominant in the upper lobes.
Cardio-Thoracic Radiology Unit / Department of experimental,
diagnostic and specialty Medicine / S.
Orsola-Malpighi Hospital / University of Bologna - Italy
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