Conflict of interest I ain’t going near no CT scanner Jack
CT in human fibrotic lung disease Technique Terminology Patterns of fibrosis Quantification
High Resolution CT technique Thin section (0.625-1.5 mm) Small field of view Edge-enhancing reconstruction Adequate inspiration Absent motion Prone and expiratory images very helpful Multiplanar images Standard window width (1500) and level (-700) Mayo JR. CT evaluation of diffuse infiltrative lung disease: dose considerations and optimal technique. Journal of thoracic imaging. 2009;24(4):252-9.
Features of lung fibrosis Reticular lines Honeycombing Ground glass attenuation or consolidation (uncommon) Traction bronchiectasis/architectural distortion Lobar volume loss Hansell DM, et al. Fleischner Society: glossary of terms for thoracic imaging. Radiology. 2008;246(3):697-722.
Reticular abnormality with traction bronchiectasis
UIP pattern Subpleural, basal predominance Reticular abnormality Honeycombing with or without traction bronchiectasis Absence of features inconsistent with UIP pattern ATS/ERS/JRS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence-based Guidelines for Diagnosis and Management. AJRCCM, 2011 Mar 15;183(6):788-824
Possible UIP Subpleural, basal predominance Reticular abnormality Absence of features inconsistent with UIP pattern ATS/ERS/JRS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence-based Guidelines for Diagnosis and Management. AJRCCM, 2011 Mar 15;183(6):788-824
IPFNET: Concordance between CT and pathologic diagnoses Pathology diagnosis CT diagnosisDefinite UIPProbable UIPPossible UIPNot UIPTotal UIP821712102 Possible UIP5194064 Inconsistent with UIP55 16 4075 Total1884292241 Yagihashi et al. Soc Thorac Radiol 2014
NSIP Basal predominance Peribronchovascular/ subpleural sparing Confluent pattern Volume loss Ground glass Reticular Traction bronchiectasis Consolidation +/- Honeycombing rare Travis et al. Am J Respir Crit Care Med. 2008;177:1338
Bleomycin induced fibrosis in rabbits Hirose et al. Am Rev Respir Dis. 1993 Mar;147(3):730-8. Lynch et al. Acad Radiol. 1997 Feb;4(2):102-7
Bleomycin induced fibrosis in rabbits Lynch et al. Acad Radiol. 1997 Feb;4(2):102-7
Quantification of lung fibrosis Semiquantitative Densitometry/CT histogram Texture-based methods
Relationship between semiquantitative assessment and physiologic impairment Wells et al. Am J Respir Crit Care Med Vol 167. pp 962–969, 2003
Relationship between semiquantitative assessment and mortality: Multivariate Baseline Variable Hazard ratio 95% Confidence Interval p Value HRCT features Overall extent of fibrosis 2.711.61, 4.55< 0.0001 % predicted DLCO 0.940.90, 0.98 0.004 Treatment assignment to IFN-γ1b 0.530.28, 0.990.04 Lynch DA, et al. Am J Respir Crit Care Med2005;172:488-93.
Histogram-based parameters Courtesy: Stephen Humphries, National Jewish Health
Relationship between quantitative histogram assessment and physiologic impairment R 2 = 0.23 P<0.0001 R 2 = 0.30 P<0.0001 R 2 = 0.20 P<0.0001 Best et al., Radiology; 2003;208:407-414
Multivariate analysis of predictors of mortality in IPF (n=167, 35 deaths) Effect Odds Ratio Estimates 95% Confidence Limits Wald Chi- Square Pr > ChiSq Kurtosis at Baseline0.579 0.32 to 1.0493.2490.0715 Mean Visual Fibrosis at Baseline CT1.104 1.018 to 1.1985.71710.0168 Best et al., Radiology; 2008 Mar;246(3):935-40.
Normal lung Reticular Abnormality Textural analysis Courtesy: Stephen Humphries, National Jewish Health
Critical features of CT assessment of fibrosis High resolution technique, with minimal motion Standardized descriptive lexicon Systematic categorization of fibrotic patterns Quantification Visual Histogram based Textural Validation against physiology, pathology, outcome