title: Increased 18F-FDG Uptake on PET/CT is Associated With Poor Arterial and Portal Perfusion on Multiphase CT.
abstract: OBJECTIVE
  To correlate 18F-FDG uptake on PET/CT with patterns of arterial and portal perfusion on multi-detector CT (MDCT) in patients with hepatocellular carcinoma (HCC) and to assess the value of variables from PET/CT and MDCT in predicting histological grades and overall survival.
  
  
  METHODS
  We retrospectively analyzed MDCT and PET/CT of 66 patients with HCC who underwent surgical treatment. Tumor peak standard uptake value (SUV) was divided by the mean liver SUV (T/LSUV). The mean tumor Hounsfield unit (HU) to mean liver HU was calculated for arterial (T/LHU-A) and portal phases (T/LHU-P). All patients were divided into three groups: I, T/LHU-A ≤l and T/LHU-P <1; II, T/LHU-A >1 and T/LHU-P <1; and III, T/LHU-A >1 and T/LHU-P ≥1. The relationships between the CT perfusion groups and T/LSUV were assessed. Multivariate logistic regression analyses were performed using clinical and imaging parameters for predicting histological grade. Overall survival curves stratified by T/LSUV and CT perfusion groups were estimated using the Kaplan-Meier method.
  
  
  RESULTS
  Statistically significant differences in T/LSUV were noted between groups I and II (2.29 [range 1.74-3.60] vs. 1.20 [range 1.07-1.58], P < 0.001) and groups I and III (2.29 [range 1.74-3.60] vs. 1.30 [range 1.07-1.43], P < 0.001). In multivariate analysis, a T/LSUV cutoff of >1.46 was the only independent predictor of tumor grade, with an odds ratio of 8.462 (95% confidence interval 1.799-39.803). Kaplan-Meier curves showed significant differences in OS according to T/LSUV >1.62, group I perfusion pattern, and T/LSUV >1.62 plus group I perfusion pattern (P = 0.04, P = 0.021, and P = 0.002, respectively).
  
  
  CONCLUSIONS
  18F-FDG PET/CT is not commonly used for detecting HCC due to its limited sensitivity. We found that increased 18F-FDG uptake is associated with decreased arterial and portal perfusion on MDCT. This can be used to preselect patients who would benefit the most from PET/CT. Meanwhile, 18F-FDG uptake remained as the only independent predictor of histological grade, and higher 18F-FDG uptake and lower perfusion pattern on MDCT were significantly related to shorter OS.
authors.affiliation: From the Departments of *Nuclear Medicine and †Radiology, Yonsei University College of Medicine, Severance Hospital, Seoul, Korea; ‡Program of Nanoscience and Technology, the Graduate School of Yonsei University College of Medicine, Seoul, Korea; and §Department of Radiology, Harvard Medical School, Brigham Women's Hospital, Boston, MA.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Hwang
authors.forename: Minwook
authors.initials: M
authors.lastname: Lee
authors.forename: Narae
authors.initials: N
authors.lastname: Lee
authors.forename: Saewhan
authors.initials: S
authors.lastname: Park
authors.forename: Chun Ki
authors.initials: CK
authors.lastname: Kim
authors.forename: Mi-Ae
authors.initials: MA
authors.lastname: Park
authors.forename: Mijin
authors.initials: M
authors.lastname: Yun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D055420:Perfusion Imaging; D011168:Portal System / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18