Solitary pulmonary nodules: Association between signal characteristics in dynamic contrast enhanced MRI and tumor angiogenesis

SummaryPurposeTo estimate the association between signal characteristic of dynamic enhanced MRI using curve types and angiogenesis in solitary pulmonary nodules.Materials and methodsThirty-six patients with a solitary pulmonary nodule (SPN) ranging in size from 6 to 37 mm (median 17 mm) underwent dynamic contrast enhanced MRI with a time interval of 10 s over a total period of 4 min. Resulting from the time–intensity curves four different enhancement curve profiles (A–D) were defined: type A with strong increase followed by early washout, type B with strong increase without washout, type C with slow increase and type D without relevant increase. Maximum peak (Pmax), slope of the first bolus transit (slope) and washout were calculated. Microvessel densities (MVD) were counted at the margins and at the center of the nodules. The mean MVD of each nodule was calculated. Enhancement characteristics were correlated with MVD grouped by diagnosis and by curve types. Curve types were correlated with the score of vascular endothelial growth factor (VEGF).ResultsThe frequency of malignancy was 55% (20/36). Using curve types for differentiation between malignant and benign SPN, the sensitivity, specificity and accuracy were 100%, 75% and 89%, respectively. The correlation between Pmax and MVDmean for all nodules was moderate (rs = 0.4, P = 0.02). A relevant correlation was found between Pmax and MVDmargin in curve type A (rs = 0.63; P = 0.04) and Pmax and MVDmean in curve type C (rs = 0.86; P = 0.006). No positive correlation was found between Pmax and MVD (mean, center and margin) in curve type B. No significant correlation was found for slope and washout. VEGF score correlated positively with curve types (rs = 0.67; P < 0.001).ConclusionA relevant association between perfusion curve profiles and angiogenesis was found in malignant nodules having early washout and in benign lesion with a slow increase of enhancement. In cases of strong signal increase without washout additional factors for enhancement must be considered. The use of curve profiles could allow for the estimation of the extent of VEGF.