Ukihide Tateishi MD, PhD, Presenter: Nothing to Disclose

Mitsuo Satake MD, Abstract Co-Author: Nothing to Disclose

Tetsuo Maeda MD, Abstract Co-Author: Nothing to Disclose

Koji Murakami MD, PhD, Abstract Co-Author: Nothing to Disclose

Yasuaki Arai MD, Abstract Co-Author: Nothing to Disclose

The present investigation was made to clarify whether the differentiation of malignant and benign non-solid solitary pulmonary nodules (SPNs) were made using FDG PET/CT.

FDG PET/CT images of 85 cases (mean age: 62 years old; range 42-78 years) with non-solid SPN were analyzed prospectively. There were 44 males and 41 females. Pathologic confirmation was obtained by surgical specimens in 19 malignant lesions and 8 benign lesions. The remaining 58 benign lesions were determined by the disappearance of the lesions on follow-up CT images. Visual score, maximum and mean standardized uptake value (SUV), and maximum and mean lesion to normal tissue ratio (LNR) were compared to clinical variables including smoking history, laboratory test results, and CT findings. The performance of diagnosis on FDG PET/CT was conducted by receiver operating characteristics (ROC) analysis. The univariate and multivariate logistic regression analyses were performed to differentiate between malignant and benign lesions.

The Az values for distinction of malignant and benign non-solid SPNs were 0.742 in maximum SUV, 0.709 in mean SUV, 0.690 in maximum LNR, 0.682 in visual score, and 0.644 in mean LNR. In the univariate analysis, significant difference was found in maximum SUV (0.76 vs. 1.30; P=0.009), mean SUV (0.58 vs. 0.91; P=0.017), size (10.2 vs. 16.1; P=0.014), maximum LNR (1.19 vs. 1.93; P=0.033), and mean LNR (1.19 vs. 1.34; P=0.041) between malignant and benign non-solid SPNs. There were no significant difference in smoking history, laboratory measurements including CRP, white blood cell count, neutrophils, lymphocytes, and tumor markers. Malignant lesions represented irregular margin (n=14, 74%), spicula (n=2, 11%), pleural indentation (n=2, 11%), cavitation (n=1, 6%) on CT. Bronchiectasis or bronchiolectasis was only found in benign non-solid SPNs and its frequency was statistically significant (P=0.001). In the multivariate logistic regression analysis, maximum SUV was only significant to differentiate between malignant and benign non-solid SPNs.

Malignant non-solid SPNs tends to represent lower maximum SUV compared with those of benign non-solid SPNs on FDG PET/CT.

Tateishi, U, Satake, M, Maeda, T, Murakami, K, Arai, Y, Solitary Pulmonary Nodule: Distinction of Malignant and Benign Non-solid Lesions on FDG PET/CT.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4408459.html