Evaluation of recurrent disease in the re-staging of colorectal cancer by 18F-FDG PET/CT: Use of CEA and CA 19-9 in patient selection.

The aim of the present retrospective study was to evaluate the sensitivity and specificity of fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing the recurrence of colorectal cancer (CRC) with regard to carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9). 18F-FDG PET/CT was performed in 100 patients for the re-staging of CRC. Therapy was discontinued prior to the examination. The mean (± standard deviation) CEA value (measured ~30 days prior to PET/CT examination) was 23.71 (±107) ng/ml, whereas the CA 19-9 value was 72 (±190.3) U/ml. Differences in CEA and CA 19-9 values in patients with scans that were positive or negative for recurrence were analyzed by means of a receiver operating characteristic (ROC) curve. ROC curves were used for the calculation of the sensitivity and specificity of 18F-FDG PET/CT for the CEA and CA 19-9 levels. The results of the 18F-FDG PET/CT were found to be associated with the CEA level (P=0.001), but not with the CA 19-9 level (P=0.43). PET/CT was positive for recurrence in 60 patients (60.0%), whose mean CEA and CA 19-9 values were 33.07±136.7 ng/ml and 75.24±192.3 U/ml, respectively. PET/CT was negative for recurrence in 40 patients (40.0%), whose mean CEA and CA 19-9 values were 10.15±30 ng/ml and 67.76±190 U/ml, respectively. On the basis of ROC curve analysis, the best compromise between sensitivity and specificity was achieved for CEA levels of 3.5 ng/ml [sensitivity, 80%; 95% confidence interval (CI), 67-89%; and specificity, 60%; 95% CI, 45-78%]. The study concluded that the detection of recurrence by 18F-FDG PET/CT in patients treated for CRC is associated with CEA, but not CA 19-9 serum levels. Moreover, 18F-FDG PET/CT should be recommended in patients with suspected CRC recurrence even when they present with CEA levels below the normal cut-off.

Factors affecting ¹8F FDOPA standardized uptake value in patients with primary brain tumors after treatment.

AIM: To investigate the factors affecting (18)F FDOPA uptake in patients with primary brain tumors (PBT) after treatment. MATERIALS AND METHODS: 97 patients with PBT (6 were grade I, 40 were grade II, 29 were grade III and 22 were grade IV) underwent (18)F FDOPA positron emission tomography/computed tomography (PET/CT) after treatment. Intervals from surgery, chemotherapy (CHT) and radiotherapy (RT) were 41.48 (±42.27), 16.04 (±29.08) and 28.62 (±34.49) months respectively. RESULTS: (18)F FDOPA uptake in the site of recurrence was not related to the interval from surgery and CHT while a significant relationship has been found with the interval from RT and tumor grade. CONCLUSIONS: The results of our study show that the interval from RT and the grade of PBT should be considered carefully when evaluating brain PET/CT scans since these factors could directly affect (18)F FDOPA uptake.

Impact of fasting glycemia and regional cerebral perfusion in diabetic subjects: a study with technetium-99m-ethyl cysteinate dimer single photon emission computed tomography.

BACKGROUND AND PURPOSE: Diabetes mellitus increases the risk of ischemic stroke. The aim of this study was to investigate the correlation between fasting plasma glucose (FPG) and changes in regional cerebral perfusion (CP) in subjects with DM. METHODS: CP was assessed in 24 subjects (mean age 44+/-2.5 years) with type 1 diabetes mellitus by single photon emission computed tomography. RESULTS: Analysis of CP during elevated FPG (224+/-24 mg/dL) showed 3 or more deficits in 42% of the subjects. A positive relationship between the number of CP deficits and FPG was observed (P<0.01), but not with age, sex, body mass index, or duration of diabetes mellitus. Regional deficits were reduced (P<0.001) with improvement in FPG (119+/-5 mg/dL). This reduction remained significant after adjustment for age, sex, and body mass index. Plasma levels of P-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, established markers of endothelial dysfunction, were significantly decreased with lower FPG. Furthermore, thiobarbituric acid reactive substance plasma levels, an index of oxidative stress, were also reduced (P<0.01). CONCLUSIONS: The present study demonstrates that changes in FPG are associated with functional changes in regional CP. Hyperglycemia-induced endothelial dysfunction may be implicated in the impaired regional CP of diabetic subjects.