title: Breast cancer with low FDG uptake: characterization by means of dual-time point FDG-PET/CT.
abstract: BACKGROUND
  Malignant breast lesions usually are differentiated by FDG-PET with a semiquantitative FDG standardized uptake value (SUV) of 2.5. However, the frequency of breast cancer with an SUV of less than or equal to 2.5 is noteworthy, and often present diagnostic challenges. This study was undertaken to evaluate the accuracy of dual-time point FDG-PET/CT with FDG standardized uptake value (SUV) calculation in the characterization of such breast tumors.
  
  
  METHODS
  Forty-nine female patients with newly diagnosed breast cancer were found to have primary breast cancer with minimally increased FDG uptake and met the criteria for inclusion in this study by having borderline levels of increased FDG uptake (SUV max less than or equal to 2.5) in the initial FDG-PET/CT images. Consequently, they underwent further delayed phase FDG-PET/CT scan for better evaluation of the disease.
  
  
  RESULTS
  Of the 49 cancer lesions; the majority were found to have rising or unvarying dual-time changes in SUV max (75.5%). The median value of SUV max increases by 25% between the early and delayed scan. The means+/-S.D. of the SUV max1, the SUV max2, and the Delta SUV max% were 1.2+/-0.6%, 1.3+/-0.9%, and 5.1+/-22.4%, respectively. The receiver-operating-characteristic (ROC) analysis proved that the highest accuracy for characterization of malignant breast lesions was obtained when a Delta SUV max% cut-off value 0.0% was used as criteria for malignant FDG uptake-change over time with sensitivity 75.5%, and false-positive rate 20.4%.
  
  
  CONCLUSIONS
  These results suggested that dual-time FDG-PET/CT imaging with standardized uptake value (SUV) estimation can improve the accuracy of the test in the evaluation of breast cancer with low FDG uptake.
authors.affiliation: Radiology Department, Menoufiya University School of Medicine, Menoufiya, Egypt. ashradio@gmail.com
authors.forename: Ashraf Anas
authors.initials: AA
authors.lastname: Zytoon
authors.forename: Koji
authors.initials: K
authors.lastname: Murakami
authors.forename: Mohamed Ramdan
authors.initials: MR
authors.lastname: El-Kholy
authors.forename: Emad
authors.initials: E
authors.lastname: El-Shorbagy
authors.forename: Osama
authors.initials: O
authors.lastname: Ebied
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18