The Role of Dynamic Magnetic Resonance Imaging in the Evaluation of Pulmonary Nodules and Masses

OBJECTIVE: The aim of our study was to determine whether or not dynamic magnetic resonance imaging (MRI) with kinetic and morphological parameters can reveal significant differences between malignant and benign pulmonary lesions, and thus to evaluate the use of dynamic MRI in the management of pulmonary nodules. PATIENTS AND METHODS: Thirty-one patients (4 women and 27 men) underwent 1.5 T MRI, where 10 consecutive dynamic series were performed every 30 s by using 3D fast low-angle shot sequences. The percentage increase in the signal intensity of the lesions was determined for each time point. Time-enhancement curves of the lesions were drawn and classified into four types: A, B, C and D. Early peak (EP) and maximum peak (MP) values of the curves were calculated and compared with the diagnoses of the patients. The usefulness of these parameters was tested statistically. In addition to the comparison of the parameters between the groups, receiver-operating characteristic analysis was used to assess sensitivity, specificity, and both positive and negative predictive values of EP and MP parameters. RESULTS: Of the 31 pulmonary lesions, 16 (52%) were malignant. These showed a stronger enhancement with higher median values of EP and MP (77.08 and 123.15, respectively) than those corresponding to the benign lesions (14.45 and 32.53, respectively). There were significant differences between the benign and malignant lesions (p < 0.001). Sensitivity, specificity, positive predictive value and negative predictive value were 75, 93, 92 and 78% for EP and 93, 86, 88 and 93% for MP, respectively. CONCLUSION: A combination of kinetic and morphological evaluation in dynamic MRI provided accurate differentiation between benign and malignant pulmonary lesions. It was a useful and noninvasive method of evaluating pulmonary nodules.