Differentiation of malignant and benign small peripheral pulmonary nodules using time-intensity curve on dynamic MRI

Abstract

Along with the increase in regularly scheduled pulmonary check-ups, there has also been an increase in the detection of nodules smaller than 20 mm. The differentiation of benign or malignant nodules is reportedly facilitated by adding contrast-enhanced MRI to high-resolution CT. However, there are few studies on peripheral pulmonary nodules smaller than 20 mm. We examined the use of contrast-enhanced MRI for peripheral pulmonary nodules smaller than 20 mm that were difficult to differentiate between benign or malignant using high-resolution CT, and compared the results with the pathological views of the excised specimens. On the time-intensity curve in the dynamic study, we classified it as "steep type", "flat type", "gradual type", and "not visible". The result was low. As for 75% of sensitivity, 42.9% of specificity, 68.6% of accuracy. However, as for 85.7% of sensitivity, 100% of specificity, 86.7% of accuracy in nodules with less than more than 15mm and 20mm of greatest dimension. The differentiation of benign or malignant nodules smaller than 15 mm is difficult by dynamic MRI, but it appears that MRI facilitates the diagnosis of nodules larger than 15 mm.