Evaluation of Indeterminate Pulmonary Nodules with Dynamic MR Imaging

Purpose: We prospectively assessed whether enhancement characteristics on dynamic magnetic resonance (MR) imaging could distinguish indeterminate pulmonary nodules. Methods: We evaluated 51 pulmonary nodules in 51 consecutive patients (11 female, 40 male; mean age, 64 years) using dynamic MR images acquired at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 120, 150, 180, 210, 240, 360, 480, 600, 720, and 840 s following injection of contrast material. We prospectively evaluated morphologic enhancement patterns, peak rate, time to peak enhancement, steepest slope, and washout of nodules and analyzed statistics to determine any differences between MR parameters, patient age, tumor size, and final diagnosis. Results: We found 25 malignant, 12 active inflammatory, and 14 benign nodules. Nodule diameter was significantly larger for malignant than nonmalignant, and benign nodules (P <= 0.01). Patients with malignant nodules were significantly older than those with nonmalignant (P=0.01) and active inflammatory (P=0.02) nodules. However, morphologic enhancement patterns, peak rate, time to peak enhancement, steepest slope, and washout characteristics at 2, 4, 8, and 12 min showed no significant difference between malignant and nonmalignant nodules and among malignant, active inflammatory, and benign nodules. Conclusion: Prospective assessment of dynamic MR images demonstrated their inadequacy for distinguishing indeterminate pulmonary nodules.