Visual and semiquantitative analysis of 82Rb uptake in malignant tumors on PET/CT: first systematic analysis.

OBJECTIVE: The objective of this study was to analyze the uptake of rubidium in malignant tumors. PARTICIPANTS AND METHODS: Sixteen malignant lesions were included. Two radiologists compared each lesion to four references (subcutaneous fat, lung, mediastinal blood pool, and liver) at rest and stress and scored as 1-4. Maximum standardized uptake value (SUV) in each lesion and four references, as well as ratios of lesion SUV to SUV of each of the references, were calculated at rest and stress. We assessed an agreement for scores of reader 1 versus reader 2 (inter-reader) at rest and stress, scores at rest versus stress (intrapatient) for reader 1 and reader 2, and lesion SUV and respective ratios at rest and stress using paired t-test and Bland-Altman analyses. RESULTS: Fifteen (94%) out of 16 lesions had a score of 3 or 4 at rest or stress or both by at least one reviewer. We did not find evidence of inter-reader bias at rest or stress or intrapatient (rest vs. stress) bias for either reader. SUV ranged from 1.0 to 8.1 at rest and from 0.7 to 6.7 at stress. There was an excellent agreement between ratios of lesion SUV to lung SUV at rest versus stress. On the extreme, there was a poor agreement between ratios of lesion SUV to liver SUV at rest versus stress. Otherwise, the agreement was good for the majority of the results, and moderate for a few others. CONCLUSION: Malignant tumors can be readily depicted and quantified on rubidium PET/CT. Further research is needed.

Frequency of high blood glucose prior to FDG PET.

PURPOSE: To assess the frequency of blood glucose level higher than 150 mg/dL in non-diabetic patients presenting for FDG PET. METHODS: We reviewed the electronic medical record (EMR) of all lymphoma patients who had at least one FDG PET/CT from July 1, 2014 through June 30, 2015. We extracted the blood glucose level at the time of the FDG PET during this 1-year time period and any previous PET scans these patients had. Patients' diabetic status was determined from EMR. RESULTS: One hundred seventeen patients with 574 scans were included: 91 non-diabetic with 429 scans and 26 diabetic patients with 145 scans. Blood glucose level ranged from 44 to 259 mg/dL: 44 to 144 mg/dL in non-diabetic patients and 73 to 259 mg/dL in diabetic patients. There was no non-diabetic patient with a glucose level higher than 150 mg/dL at any occasion. Only one scan was performed with 144 mg/dL of glucose. All other scans were performed with a glucose level less than 140 mg/dL. There were nine diabetic patients with glucose level less than 150 mg/dL prior to all of their scans and 17 diabetic patients with a glucose level higher than 150 mg/dL prior to PET at least on one occasion. CONCLUSIONS: In all non-diabetic patients, blood glucose level was below the lower limit of the recommended range prior to all their FDG PET scans while this was not the case in diabetic patients. We conclude that measuring blood glucose level prior to FDG PET may be limited to diabetic patients.