Fasting and nonfasting iodine-123-idophenylpentadecanoic acid myocardial SPECT imaging in coronary artery disease

Iodine-123-labeled idophenylpentadecanoic acid (IPPA) metabolic imaging has been shown to be clinically useful for the identification of myocardial vi ability in patients with coronary artery disease and left ventricular dysfu nction. Imaging is usually performed under fasting conditions since nonfast ing conditions may affect myocardial uptake of I-123-IPPA. The purpose of t his study was to examine the impact of dietary condition on I-123-IPPA meta bolic imaging. Methods: Forty patients with stable coronary artery disease underwent, in randomized order and on separate days, I-123-IPPA SPECT myoca rdial imaging under fasting and nonfasting conditions. Patients were inject ed with I-123-IPPA (4-5 mCi) at rest with imaging performed at 4 (initial) and 30 (delay) min. For each image (initial and delay images), 10 segments were analyzed by three experienced observers without knowledge of patient i dentity or dietary condition using a 5-point grading system (0 = no uptake to 4 = normal uptake). A summed global score was obtained for each image by adding the scores for all 10 segments. Image quality was assessed using a 3-point grading system. Results: Visual agreement for normal and abnormal s egments between fasting and nonfasting conditions was 82% (kappa = 0.63). T here were no significant differences in the summed global scores for both c onditions. Image quality was equivalent for both conditions in 65% of cases and superior under the nonfasting condition in 25% of cases. Conclusion: I mage quality as well as the presence, location and severity of defects are similar under fasting and nonfasting conditions with I-123-IPPA. Therefore, fasting is not necessary before I-123-IPPA SPECT imaging for the assessmen t of myocardial viability.