AU - Shah, Omair AU - Choh, Naseer AU - Shera, Faiz AU - Gojwari, Tariq AU - Suhail, Jan AU - Shafi, Fahad AU - Jan, Rafi TI - Computed Tomography Severity Grading of Chronic Obstructive Pulmonary Disease based on Volumetric Assessment of Inspiratory and Expiratory Scans PT - JOURNAL ARTICLE TA - UMSU-Press JN - UMSU-Press VO - 6 VI - 4 IP - 4 4099 - http://ijrabms.umsu.ac.ir/article-1-137-en.html 4100 - http://ijrabms.umsu.ac.ir/article-1-137-en.pdf SO - UMSU-Press 4 ABĀ  - Background & Aims: To determine attenuation threshold for detection and quantification of air trapping in obstructive airway disease. Quantify airway dysfunction in patients of obstructive airway disease & its correlation with pulmonary function tests. Materials & Methods: Paired HRCT scans of 48 patients were done and correlated with Pulmonary Function Tests taken within 2 weeks of the study. Threshold attenuation value on expiratory scan that signifies air trapping was obtained by correlating relative volumes with PFT parameters (PEF 25-75% & RV/TLC). The lung volumes at this threshold were then correlated with PFT values signifying airway dysfunction (FEV1, FEV1/FVC and PEF 25-75%) and airway dysfunction was then quantified based on these volumes. Results: Maximum correlation of PFT parameters signifying air trapping is with relative volume of limited lung at -850HU (l850) (p<0.005) which was taken as the threshold for air trapping. Using this threshold (-850HU), we calculated the relative volume change of limited and whole lung (l850 & t850) and expiratory relative volume of limited and whole lung (ERV l850 & ERV t850). Significant correlation was seen between l850 and PFT parameters signifying airway dysfunction (p<0.005). A severity classification of obstructive airway disease was formulated based on l850 and classified patients into mild (l850<-30%), moderate (l850= -20 - -30%), severe (l850 =-10 - -20%), and very severe (l850 > -10%). Conclusion: l850 can be used as a CT parameter to quantify airway dysfunction irrespective of presence or absence of emphysema. Severity classification of obstructive airway disease was formulated based on l850. CP - IRAN IN - SKIMS,SOURA LG - eng PB - UMSU-Press PG - 241 PT - orginal article YR - 2020