The role of quantitative (18)F-FDG PET studies for the differentiation of malignant and benign bone lesions.
The role of quantitative (18)F-FDG PET studies for the differentiation of benign and malignant bone lesions is still an open question.


METHODS
Our evaluation included 83 patients with 37 histologically proven malignancies and 46 benign lesions. Thirty-five of the 46 benign lesions were histologically confirmed. The (18)F-FDG studies were accomplished as a dynamic series for 60 min. Evaluation of the (18)F-FDG kinetics was performed using the following parameters: standardized uptake value (SUV), global influx (Ki), computation of the transport constants K1-k4 with consideration of the distribution volume (VB) according to a 2-tissue-compartment model, fractal dimension based on the box-counting procedure (parameter for the inhomogeneity of the tumors).


RESULTS
The mean SUV, the vascular fraction VB, K1, and k3 were higher in malignant tumors compared with benign lesions (t test; P < 0.05). Although the (18)F-FDG SUV was helpful to differentiate benign and malignant tumors, there was some overlap, which limited the diagnostic accuracy. On the basis of the discriminant analysis, the SUV alone showed a sensitivity of only 54.05%, a specificity of 91.30%, and a diagnostic accuracy of 74.70%. The fractal dimension was superior and showed a sensitivity of 71.88%, a specificity of 81.58%, and an accuracy of 77.14%. The combination of SUV, fractal dimension, VB, K1-k4, and Ki revealed the best results with a sensitivity of 75.86%, a specificity of 97.22%, and an accuracy of 87.69%. Bayesian analysis showed true-positive results at the level of 0.8 for a low prevalence of disease (0.235) if the full kinetic data were used in the evaluation.


CONCLUSIONS
(18)F-FDG PET has a high specificity for the exclusion of a malignant bone tumor. Evaluation of the full (18)F-FDG kinetics and the application of discriminant analysis are required and can be used prospectively to classify a bone lesion as malignant or benign.
Dimitrakopoulou-Strauss
Antonia
A
Division of Oncological Diagnostics and Therapy, German Cancer Research Center, E0105 Medical PET Group, Im Neuenheimer Feld 280, Heidelberg, D-69120 Germany. a.dimitrakopoulou-strauss@dkfz.de
Strauss
Ludwig G
LG
Heichel
Thomas
T
Wu
Hua
H
Burger
Cyrill
C
Bernd
Ludger
L
Ewerbeck
Volker
V
D001499:Bayes Theorem; D001847:Bone Diseases / Q000000981:diagnostic imaging; D001859:Bone Neoplasms / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18