Stellenwert der Positronen-Emissions-Tomographie (PET) mit F-18 Fluordeoxyglukose (FDG) in der Diagnostik von Mammatumoren

Introduction: In a prospective study 84 patients with 111 histologically confirmed breast tumours underwent positron emission tomography (PET). Aim of this study was to evaluate the diagnostic accuracy of PET imaging for detection of malignant breast tumours. Material and Methods: Transmission and emission scans were carried out after intravenous injection of F-18 fluorodeoxyglucose (FDG). For visual image analysis tracer uptake of breast tissue was classified in three categories (a: 'unlikely'; b: 'probable'; c: 'definite' malignant tissue). For quantitative image analysis standardized uptake values (SUV) were calculated using the region of interest (ROI) technique. Results: Regarding only 'definite' findings representing malignancy resulted in a sensitivity of 61% and a corresponding specificity of 98%. Including also 'probable' PET findings yielded a sensitivity of 80% and a specificity of 78%. The difference between SUV values of malignant (3.3 ± 1.8) and benign (1.4 ± 0.5) tumours was statistically highly significant (p = 0.001). Receiver operating characteristic (ROC) curve analysis showed a sensitivity of 62% and a specificity of 91% at a threshold SUV value of 2.1. After correction for partial volume effects sensitivity increased to 78% with a corresponding specificity of 90%. Sensitivity of PET imaging was influenced by tumour size. Tumours smaller than one centimetre in diameter were not reliably detectable. Conclusion: Positron emission tomography may be helpful in patients with unclear conventional diagnostic findings to determine the staging of breast tumours larger than one centimeter with high diagnostic accuracy.