Narinder S. Paul MD, Presenter: Research funding, Toshiba Corporation

Eta Prezelj, Abstract Co-Author: Nothing to Disclose

Ravi Menezes PhD, Abstract Co-Author: Nothing to Disclose

Demetris Andrea Patsios MBBCh, Abstract Co-Author: Nothing to Disclose

Heidi C. Roberts MD, Abstract Co-Author: Nothing to Disclose

Kenneth Chapman, Abstract Co-Author: Nothing to Disclose

To correlate 4D dynamic low dose CT virtual bronchoscopy (DLD-VB) with pulmonary function tests (PFT) in detection of Tracheobronchomalacia (TBM). 

A prospective study recruiting 50 patents presenting with non-specific respiratory symptoms and no known history of airways or lung disease and stable symptoms. DLD-VB was performed using a volume CT with 320 x 0.5mm detector rows covering the central airway from the thoracic inlet to the first bronchial divisions. Patients maintained a 2s inspiratory breath-hold then exhaled quickly while 5 volume CT acquisitions using 120kv, 22.5-37.5mAs were performed. 0.5/0.5mm transaxial CT images were reconstructed using mediastinal and lung algorithms, 4D DLD-VB cine loops were created. All images were interrogated blinded to PFT results to record evidence of tracheomalacia i.e. reduction in AP airway diameter of ≥50%; as none (normal) or present; graded as tracheomalacia (TM), bronchomalacia (BM) or tracheobronchomalacia (TBM). Patients were grouped by PFT severity of COPD into; control group (none) – no COPD, GpA – mild, GpB-moderate and GpC-severe. Statistical analysis performed with Chi-square and Fisher’s exact test. Console DLP (mGy*cm) was read to determine radiation dose.  

50 patients were enrolled (23M), 68y (50-85y), BMI = 29.2 (19.0-48.3). PFT grouping of COPD severity; none =12 (24%), mild=9 (18%), moderate=20 (40%) and severe=9 (18%). DLD-VB grouping of airways disease; none =27 (54%), TM=13 (26%), BM=6 (12%), TBM=4 (8%). Patients with normal DLD-VB had PFT grading of COPD as; none=7 (58%), GpA=5 (56%), GpB=12 (60%), GpC=3 (33%). Patients with TM, TBM or BM had PFT grading of COPD as; none=5 (42%), GpA=4 (44%), GpB=8 (40%), GpC=6 (67%) chi-square test p=0.636. After combining PFT groups (control + GpA + GpB) = GpD and comparing to GpC; with normal DLD-VB; GpD=24 (59%), GpC=3 (33%) and with TM, TBM or BM; GpD=17 (41%), GpC=6 (67%). Fisher’s exact test p=0.27. DLP = 286.4 (190.3-359.3), effective dose 4.0mSv (2.7-5.0mSv).

4D DLD-VB demonstrates significant airways collapse across a spectrum of PFT fndings from normal to severe COPD. Increased COPD severity trends to more severe airways collapse.

4D Dynamic Low Dose CT Virtual Bronchoscopy is a promising tool for detection of Tracheobronchomalacia, is easy to perform and has an acceptable radiation dose profile. 

Paul, N, Prezelj, E, Menezes, R, Patsios, D, Roberts, H, Chapman, K, 4D Dynamic Low Dose CT Virtual Bronchoscopy for Diagnosis of Tracheobronchomalacia.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12034915.html