Comparison of Usual Interstitial Pneumonia and Nonspecific Interstitial Pneumonia: Quantification of Disease Severity and Discrimination between Two Diseases on HRCT Using a Texture-Based Automated System

Abstract

ObjectiveTo evaluate the usefulness of an automated system for quantification and discrimination of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP).Materials and MethodsAn automated system to quantify six regional high-resolution CT (HRCT) patterns: normal, NL; ground-glass opacity, GGO; reticular opacity, RO; honeycombing, HC; emphysema, EMPH; and consolidation, CONS, was developed using texture and shape features. Fifty-four patients with pathologically proven UIP (n = 26) and pathologically proven NSIP (n = 28) were included as part of this study. Inter-observer agreement in measuring the extent of each HRCT pattern between the system and two thoracic radiologists were assessed in 26 randomly selected subsets using an interclass correlation coefficient (ICC). A linear regression analysis was used to assess the contribution of each disease pattern to the pulmonary function test parameters. The discriminating capacity of the system between UIP and NSIP was evaluated using a binomial logistic regression.ResultsThe overall ICC showed acceptable agreement among the system and the two radiologists (r = 0.895 for the abnormal lung volume fraction, 0.706 for the fibrosis fraction, 0.895 for NL, 0.625 for GGO, 0.626 for RO, 0.893 for HC, 0.800 for EMPH, and 0.430 for CONS). The volumes of NL, GGO, RO, and EMPH contribute to forced expiratory volume during one second (FEV1) (r = 0.72, β values, 0.84, 0.34, 0.34 and 0.24, respectively) and forced vital capacity (FVC) (r = 0.76, β values, 0.82, 0.28, 0.21 and 0.34, respectively). For diffusing capacity (DLco), the volumes of NL and HC were independent contributors in opposite directions (r = 0.65, β values, 0.64, -0.21, respectively). The automated system can help discriminate between UIP and NSIP with an accuracy of 82%.ConclusionThe automated quantification system of regional HRCT patterns can be useful in the assessment of disease severity and may provide reliable agreement with the radiologists' results. In addition, this system may be useful in differentiating between UIP and NSIP.

Effects of emphysema on physiological and prognostic characteristics of lung function in idiopathic pulmonary fibrosis

“…Although there is a risk of misclassification, our AQS showed substantial agreement with visual assessment (by S.M.L.) in the evaluation of emphysema extent (κ = 0.708, P < 0.001), similar to previous studies .…”

“…To estimate the volume of each regional pattern, the area of each class was multiplied by the slice thickness of the HRCT image. The details have been described in previous studies . Emphysema extent was calculated as the proportion of emphysema within the whole lung volume.…”

“…The details have been described in previous studies. 16,17 Emphysema extent was calculated as the proportion of emphysema within the whole lung volume. An emphysema extent of <5% was regarded as insignificant; patients with <5% emphysema were classified as the no/trivial emphysema group.…”

Idiopathic Pulmonary Fibrosis: Diagnosis and Prognostic Evaluation

“…This study is important because it emphasizes the element ‘tempo' as an important clinical category. A CT scan may predict slow progression of the disease when honeycomb changes are not detectable, emphysema profusion is low and HRCT scoring of fibrosis is also low [20]. IPF patients with high mast cell density in surgical lung biopsy specimens seem to have a slower decline in forced vital capacity (FVC) [21].…”

Idiopathische pulmonale Fibrose: Diagnostik und prognostische Beurteilung

“…Während die klinischen Merkmale der sporadischen IPF gut beschrieben sind, sind bei der familiären IPF die Aspekte klinische Präsentation, Komplikationen und Outcome der Patienten noch unzureichend definiert, und die Frage ist offen, ob familiäre Formen der IPF einen spezifisch anderen Verlauf haben als sporadische, sei es als Folge genetischer Einflüsse oder anderer Faktoren. In mehreren Veröf-fentlichungen sind die klinischen Merkmale von familiären und sporadischen IPF-Patienten verglichen worden; dabei wurden, abgesehen von einem niedrigeren Durchschnittsalter zum Zeitpunkt der Diagnosestellung bei der familiären Form, keine Unterscheidungsmerkmale zwischen den beiden Gruppen festgestellt [15] [20]. Bei IPFPatienten mit hoher Mastzelldichte in der chirurgischen Lungenbiopsieprobe scheint die forcierte Vitalkapazität (FVC) langsamer abzunehmen [21].…”