Relationship Between The Time-density Curves And Image Feature Of Focal Ground Glass Opacity

Objective:To study the time—density curve TDC and the image feature of focal groundglass opacity（fGGO），evaluate the role of TDC in the differential diagnosis of fGGO．Materials and Methods:Clinical data，the size，attenuation value and features(shape，margin，interface，internal characteristics，adjacent structure)of the lesions in24cases with fGGOconfirmed by pathology or anti-inflammatory therapy were analyzed．The differencesbetween benign and malignant fGGO were analyzed by using the Fisher exact test.Thefocal ground glass opacity underwent CT perfusion imaging after intravenous injectionof50ml of contrast medium．Then the TDC was created.Results:11cases of adenocarcinoma,6cases of bronchoalveolar carcinoma, atypicaladenomatous hyperplasia in2cases,4cases of inflammatory lesion, Focal interstitialfibrosis in1cases. Adenocarcinoma、BAC and AAH were considered maglinant,inflammatory disease and FIF were considered benign.1The morphological features of fGGOIn terms of clinical data,the size and attenuation value of the lesions were nostatistical differences between benign and malignant fGGO. The shape，interface andpleural indentation sign were significantly different between benign and malignantfGGO．The margin were no statistical differences between benign and malignant fGGO.2The Time-density Curves of fGGOThe TDC showed2types in adenocarcinoma．Type I：the curve ascended anddescended slowly．the whole curve was flat，the end of the curve was higher than thelevel before enhancement；Type II：the curve ascended slowly，no descending，it kepton ascended slowly． 3types of TDC were showed in bronchoalveolar carcinoma．Type I：the curveascended suddenly，after reaching the peak value，it descended slowly，the end of thecurve was higher than the level before enhancement；Type II is similar to type I ofadenocarcinoma；type III is similar to type II of adenocarcinoma.The type of TDC in atypical adenomatous hyperplasia is similar to type I ofadenocarcinoma．The TDC showed2types in inflammation．Type I：the curve ascended slowly，but descended obviously. Type II is similar to type I of adenocarcinoma.The type of TDC in Focal interstitial fibrosis is similar to type I ofadenocarcinoma.Conclusion:The morphological features have important value in diagnosing differencefGGO．There have distinct TDC between benign and malignant fGGO，and there is animportant value in the differential diagnosis of fGGO with help of the morphologicalfeatures.