Combined anatomical MRI differentiates pulmonary invasive adenocarcinoma from tuberculoma in noncalcified nodule: a retrospective comparison of CT with MRI

Abstract

Objective: MRI as a non-ionizing modality can be a complementary tool for nodules assessment. This study is aimed to evaluate the potential of the combined conventional and modified anatomical MRI sequences for differential diagnosis of invasive adenocarcinoma (IAC) and tuberculoma. Materials and methods:Sixty-seven patients (median 54 years, range 18-82 years) with 82 noncalcified nodules (mean 19.56±6.85 mm, range 7-30 mm) underwent CT and MRI (T1WI-starVIBE, T1WI-VIBE, T2WI-TSE-fBLADE). Two radiologists independently assessed nodule dimensions and morphologic features (margin, morphology, lobulation, spiculation, cavity, air bronchogram, pleural indentation). Comparison of categorical variables was performed using Chi-square test. The inter-method agreement of morphologic features assessment by CT and MRI sequences were compared using Kappa test. Multivariate logistic regression analyses were applied to identify independent predictors to IAC. ROC analysis was performed to investigate the differential diagnosis capability. Results: Thirty-eight IACs and 44 tuberculomas were identified. Readers 1 and 2 underestimated the nodules mean diameter with T1WI-starVIBE (T1WI-VIBE, T2WI-TSE-fBLADE) by 0.86±1.71 mm (1.19±2.06 mm, 0.15±1.96 mm) and 0.99±1.75 mm (1.27±2.04 mm, 0.19±1.91 mm). The inter-method agreements between MRI and CT were “fair” to “excellent” in the evaluation of morphological features except for spiculation (0.318≦Kappa≦0.895). Compared with the tuberculoma group, the IAC group was significant with unclear margin (T1WI-starVIBE, T1WI-VIBE), irregular morphology (CT, MRI), lobulation (CT, MRI), spiculation (T1WI-starVIBE, T2WI-TSE-fBLADE) and air bronchogram (CT, T1WI-starVIBE and T1WI-VIBE) (P﹤0.05). The AUC values for the logistic model by the combination of CT and MRI were 0.867/0.877 (reader 1/2: sensitivity 73.68%/76.32%, specificity 86.36%/86.36%) and were significantly higher than that by T1WI-starVIBE (P=0.002) and T1WI-TSE-fBLADE (P=0.027) (reader 1), as well as higher than that by CT (P=0.045) and T1WI-starVIBE (P=0.003) (reader 2). Conclusion: The combined conventional and modified anatomical MRI sequences has diagnostic potential in distinguishing pulmonary IAC from tuberculoma.