Predictive Value of 18F-FDG PET/CT for Vascular Invasion in Patients With Hepatocellular Carcinoma Before Liver Transplantation.

BACKGROUND: Positron emission tomography-computed tomography using F-fluorodeoxyglucose (F-FDG PET/CT) has been widely used in oncology. Vascular invasion of hepatocellular carcinoma (HCC) is associated with a high risk of tumor recurrence and low survival rates after liver transplantation (LT). This retrospective study determined the predictive value of F-FDG PET/CT for vascular invasion in patients with HCC before LT. METHODS: Sixty-five patients with HCC who underwent F-FDG PET/CT before LT were retrospectively included between January 2010 and July 2012. Volumes of interest (VOIs) were drawn for the tumors and normal liver tissues, and the standardized uptake value (SUV) in each VOI was measured. The maximal SUV (SUVmax) of the tumor, the ratio of tumor SUVmax to normal liver SUVmax (TSUVmax/LSUVmax), and the ratio of tumor SUVmax to normal liver SUVmean (TSUVmax/LSUVmean) were measured. The predictive value of metabolic parameters and conventional prognostic factors were analyzed. RESULTS: Vascular invasion was pathologically confirmed in 15 (23.08%) of 65 patients. Compared with patients without vascular invasion, patients with vascular invasion exhibited significantly higher serum alpha-fetoprotein (AFP) (P < 0.001), larger tumor size (P = 0.001), higher tumor number (P = 0.017), and higher SUVmax, TSUVmax/LSUVmax ratio, and higher TSUVmax/LSUVmean ratio (P = 0.008, P = 0.002, and P = 0.006, respectively). Univariate analysis revealed that SUVmax, TSUVmax/LSUVmax ratio, and TSUVmax/LSUVmean ratio of FDG PET/CT were significantly associated with vascular invasion in patients with HCC before LT (P = 0.019, P = 0.018, and P = 0.015, respectively). Multivariate analysis revealed that the TSUVmax/LSUVmean ratio of F-FDG PET/CT was a significant predictor of vascular invasion (P = 0.04) and that the TSUVmax/LSUVmax ratio of F-FDG PET/CT was an independent predictor of vascular invasion, although this finding demonstrated borderline statistical significance (P = 0.06) in patients with HCC before LT. CONCLUSIONS: According to the study results, the TSUVmax/LSUVmean ratio is an independent and significant predictor of vascular invasion, and the TSUVmax/LSUVmax ratio of F-FDG PET/CT is an independent predictor of vascular invasion, which is the main negative outcome after LT. Therefore, FDG PET/CT can provide vital information for determining prognosis and selecting an optimal candidate of LT for HCC.

FDG PET/CT of a late-term pregnant woman with breast cancer.

A 38-year-old pregnant woman at 26-week gestation with left breast cancer requested an FDG PET/CT scan for more detailed staging of her breast cancer before treatment. After discussing the potential radiation-related risk and estimating possible absorbed dose to fetus, she consented for examination. By using a low-radiation-dose CT protocol and administration of routine 370-MBq FDG without diuresis, the resultant calculated (using existing models to predict fetal radiation exposure) fetal dose from CT and FDG would be 3.60 mGy and 6.29 mGy, respectively. In contrast to the existing few literatures, our case also demonstrated previously unreported uptake in the fetal kidneys.