Sensitivity of FDG PET, GLUT1 expression and proliferative index in bronchioloalveolar lung cancer.

OBJECTIVE: To estimate the sensitivity of [F] fluorodeoxyglucose (FDG) positron emission tomography (PET) and to assess the expression of glucose transporter 1 (GLUT1) and proliferative index (PI) in bronchioloalveolar lung cancer (BAC). METHODS: Twenty-four patients with resected BAC underwent preoperative PET between October 1996 and February 2003. The surgical specimens were re-examined, and 18 patients who fulfilled the 1999 WHO definition for BAC were included in the study. The PET images were reviewed in order to determine the positive (PET+) and negative (PET-) tumours on PET. The pathology slides were stained with antibodies to GLUT1 and Proliferating cell nuclear antigen (PCNA) in order to determine GLUT1 expression and PI, respectively. RESULTS: There were 13 cases of PET+ BAC (sensitivity, 72%; confidence interval, 52-93%); seven of them were GLUT1+ cases and six were GLUT1-. The stromal cell PI was significantly higher in GLUT1+ BAC compared to GLUT- BAC (50.9+/-17.1 vs. 33.2+/-14.2, P=0.0286), and higher in PET+ BAC compared to PET- BAC (45.5+/-15.3 vs. 29.6+/-19.6, P=0.0854). CONCLUSION: After applying the 1999 WHO criteria, the sensitivity of PET for detecting BAC is still relatively low. Other glucose transporters such as GLUT3 likely play a role in FDG uptake in BAC. GLUT1+ or PET+ BAC tumours have a higher stromal cell PI when compared to GLUT1- BAC or PET- BAC tumours, respectively.

Intra-individual variability of cardiac uptake on serial whole-body 18F-FDG PET.

OBJECTIVE: To measure the variability of cardiac uptake on serial whole-body F-FDG PET scans. METHODS: Two hundred and eighteen whole-body PET scans were performed in 47 patients with different primary malignancies between October 1996 and April 2003 on a dedicated PET system. The number of scans per patient ranged between four and nine. Two experienced nuclear medicine physicians reviewed the scans retrospectively using the non-attenuation corrected images to assess the cardiac FDG uptake. Patients with cardiac uptake less or equal to lung uptake were assigned in the "low" uptake group, and those with cardiac uptake more than the lung uptake were assigned to the "high" uptake group. The reproducibility of cardiac uptake on serial whole-body PET scans and the effect of age, sex, weight, diabetes and primary diagnosis on cardiac uptake was evaluated. RESULTS: There was very good reproducibility (intra-class correlation coefficient=0.77) of individual cardiac FDG uptake on serial whole-body PET scans. Diabetics (n=6) in comparison to non-diabetics were less likely to have high cardiac uptake (odds ratio (OR)=0.24, P<0.05). Patients with lymphoma (n=12) in comparison to patients with other primary diagnoses were more likely to have high cardiac uptake (OR=8.6, P<0.05). There was no association between cardiac uptake and age, sex or weight. CONCLUSION: Cardiac FDG uptake on whole-body PET does not appear to change significantly over time. It is likely that uptake is determined by individual characteristics; these likely include diabetes and primary diagnosis of lymphoma.