Solid or Partly Solid Solitary Pulmonary Nodules: Their Characterization Using Contrast Wash-In and Morphologic Features at Helical CT

摘要

Background: Solitary pulmonary nodule (SPN) evaluation based on analyses of combined wash-inn(WI) and washout (WO) values obtained by helical dynamic CT (HDCT) scanning is useful fornmalignant SPN characterization, because this method has higher specificity and accuracy thannthat based on analyses of WI values only. However, increased specificity results in reducednsensitivity and the missing of malignant SPNs. Thus, the purpose of this study was to seek the mostneffective method for SPN characterization during HDCT scanning.nMethods: After obtaining unenhanced CT scans, dynamic CT scanning was performed using anhelical technique (images were obtained at 30, 60, 90, and 120 s, and at 5 and 15 min after theninitiation of IV contrast administration) in 486 patients with a solid or partly solid SPN. Diagnosticnefficacies were compared for three approaches involving considerations of WI values (innHousfield units [HU]) only, both WI and WO HU values, and WI HU values and morphologicncharacteristics.nResults: Considering WI values only (> 25 HU), sensitivity, specificity, and accuracy for malig-nnancy were 98% (233 of 237 nodules), 46% (114 of 249 nodules), and 71% (347 of 486 nodules),nrespectively. Using both a WI value of > 25 HU and a WO value of 5 to 36 HU, the correspondingnvalues were 89% (212 of 237 nodules), 79% (197 of 249 nodules), and 84% (409 of 486 nodules),nrespectively; for a WI value of > 25 HU and a malignant morphology, the corresponding valuesnwere 92% (219 of 237 nodules), 79% (197 of 249 nodules), and 86% (416 of 486 nodules),nrespectively (these values were significantly different between the WI-only group and the otherntwo groups; p u0001 0.001).nConclusions: The efficacy of SPN evaluation based on analyses of WI values plus morphologicnfeatures during HDCT scanning appears to be equivalent to that based on analyses of WI plusnWO values, thus obviating the need for WO scans, which saves time and reduces radiationnexposure of the patient. (CHEST 2007; 131:1516–1525)