First-pass perfusion imaging of solitary pulmonary nodules with 64-detector row CT: comparison of perfusion parameters of malignant and benign lesions.

The purpose of this study was to determine the usefulness of first-pass whole nodule perfusion imaging in the differentiation of benign and malignant solitary pulmonary nodules (SPNs). 77 patients with non-calcified SPNs (46 malignant, 22 benign and 9 active inflammatory) underwent first-pass perfusion imaging with a 64-detector row CT scanner. Perfusion, peak enhancement intensity (PEI), time to peak (TTP) and blood volume (BV) were measured and statistically compared among different groups. Mean perfusion, PEI and BV for benign SPNs were significantly lower than those for malignant nodules (p<0.05) and active infections (p<0.05), but the differences were not statistically significant between malignant tumours and active infections (p>0.05). Receiver operating characteristic (ROC) curve analysis showed that SPNs with perfusion greater than 30.6 ml min(-1) ml(-1), PEI higher than 23.3 HU or BV larger than 12.2 ml per 100 g were more likely to be malignant. In conclusion, first-pass perfusion imaging with 64-detector row CT is a feasible way of assessing whole nodule perfusion and helpful in differentiating benign from malignant SPNs.