New literature is emerging regarding the use of dynamic MRI to distinguish benign from malignant SPN. Dynamic MRI values have been found to reflect the quantitative and morphologic characteristics of microvessels in SPNs, similar in concept to dynamic CT imaging.124 In a study of 202 SPNs,125 dynamic MR images were obtained before and up to 8 min after IV injection of gadopentetate dimeglumine using T1-weighted spin-echo sequences. With ≤ 110% maximum enhancement ratio as a cutoff value, the PPV for malignancy was 92%; sensitivity, 63%; and specificity, 74%. With ≥ 13.5%/min slope as a cutoff value, sensitivity, specificity, PPV, and NPV for malignancy were 94%, 96%, 99%, and 74%, respectively. A prospective study of 175 patients with 202 SPNs126 was recently performed comparing dynamic MRI, dynamic CT imaging, and PET-CT imaging to distinguish benign from malignant SPNs. On dynamic MRI, with a slope of enhancement ratio cutoff of 0.04/s, the sensitivity, specificity, PPV, NPV, and accuracy were 96.3%, 82.1%, 95.7%, 84.2%, and 93.6%, respectively. These results were superior to combined PET-CT and dynamic CT imaging, and have opened up a promising new avenue of research in the use of imaging modalities to characterize SPNs.