Molecular imaging societies have numerous recommendations for patients with diabetes who undergo fluoride-18 fluorodeoxyglucose (FDG) PET/CT tumor imaging. According to new research published in the Journal of the American College of Radiology, however, many providers are not explaining these things to patients when appointments are scheduled.
“Common recommendations include (1) fasting for 4 hours before the examination, (2) ensuring that blood glucose is less than 200 mg/dL, (3) discontinuing the use of short-acting insulin 4 hours before the examination, (4) discontinuing long-acting insulin and possibly metformin after the midnight preceding the test, and (5) preferentially scheduling patients with diabetes mellitus for morning appointments,” explained author Andrew Kaiser, MD, from the department of radiology at the University of Michigan in Ann Arbor, and colleagues. “Despite consistency across guidelines, patient preparation may vary from center to center, and stated policy may not always align with what actually occurs in clinical practice.”
To find out if these factors were being addressed during the scheduling process, Kaiser et al. called 65 nuclear medicine providers three times each in March 2017, following a script where the caller inquired about ordering a PET scan for their diabetic grandmother. “She has cancer and is diabetic, but I’m not sure what medications she is on—its either insulin or something oral,” the caller said each time “I was wondering whether these medications affect how you schedule patients for PET/CT.” The team also contact program directors from 33 academic institutions by email, requesting copies of their written protocol related to FDG PET/CT tumor imaging for patients with diabetes.
Overall, the call center contact did not explain recommendations for FDG PET/CT exams for patients with diabetes 47 percent of the time. A preferred examination time—the morning, for example—was not mentioned 91 percent of the time. In addition, a glucose threshold was only mentioned in 29 percent of phone calls.
“Our primary finding is that relevant diabetes-specific information is commonly withheld by nuclear medicine call centers throughout the United States when discussing oncologic FDG PET/CT, despite local and national policies indicating its importance,” the authors wrote. “When information is provided, it is often heterogeneous, incomplete, and different than national guidelines.”
This is so crucial, Kaiser and colleagues explained, because insulin can reduce the diagnostic sensitivity of FDG PET/CT imaging. Inappropriate insulin administration can also lead to hypoglycemia or hyperglycemia.
Though the authors think more research is needed to provide patients with the most accurate, helpful recommendations possible, they did note that advocacy is needed from more national organizations to help improve this “nationwide disconnection” and help correct information get properly communicated to patients.