J Nucl Med 2001 Dec;42(12):1730-6
Myocardial glucose utilization and optimization of (18)F-FDG PET imaging in
patients with non-insulin-dependent diabetes mellitus, coronary artery disease,
and left ventricular dysfunction.
Vitale GD, deKemp RA, Ruddy TD, Williams K, Beanlands RS.
In patients with non-insulin-dependent diabetes mellitus (NIDDM), FDG PET
imaging is often problematic because of poor uptake of FDG. Different protocols
have been used; however, these have not been directly compared in patients with
NIDDM who have both coronary artery disease (CAD) and severe left ventricular (LV)
dysfunction, for which defining viability is most relevant. The aim of this
study was to better define the optimal means of FDG PET imaging, assessed by
image quality and myocardial glucose utilization rate (rMGU), among 3 imaging
protocols in patients with NIDDM, CAD, and severe LV dysfunction. METHODS: Ten
patients with NIDDM, CAD, and severe LV dysfunction (mean ejection fraction,
29.8% +/- 7.1%) underwent dynamic FDG PET scanning using 3 different protocols:
the standard protocol, consisting of oral glucose loading or a supplemental
insulin bolus based on fasting glucose; the niacin protocol, consisting of
pretreatment with niacin to lower free fatty acids; and the insulin clamp
protocol, consisting of hyperinsulinemic euglycemic clamp. Image quality was
satisfactory with at least 1 approach in 8 patients, who formed the primary
analysis group. RESULTS: Myocardium-to-blood-pool ratios were significantly
higher with the insulin clamp (standard, 1.7 +/- 1.2; niacin, 1.6 +/- 1.0;
insulin clamp, 3.4 +/- 2.5 [P < 0.05 vs. standard and niacin]). Values for
rMGU were higher with the insulin clamp (standard, 0.11 +/- 0.07 micromol/g/min;
niacin, 0.12 +/- 0.11 micromol/g/min; insulin clamping, 0.22 +/- 0.12 micromol/g/min
[P = 0.004 vs. standard and 0.07 vs. niacin]). CONCLUSION: The hyperinsulinemic
euglycemic clamp yielded the highest FDG PET image quality and the highest rMGU
in a comparison with the standard and niacin protocols in this difficult group
of patients with NIDDM, CAD, and severe LV dysfunction. The hyperinsulinemic
euglycemic clamp may be the preferred method for FDG PET viability imaging in
this population. Larger clinical trials are needed to assess whether accuracy is
greater with this approach.
