Improved uniformity in tomographic myocardial perfusion imaging with attenuation correction and enhanced acquisition and processing.

Unlabelled: Tissue attenuation results in nonuniform myocardial perfusion images with significant sex differences. New SPECT imaging protocols to correct attenuation are currently under investigation. This study was performed to assess the effects of attenuation correction (AC) on overall image uniformity compared with more conventional imaging protocols in both men and women.

Methods: Thirty-nine patients (19 men, 20 women) with less than a 5% likelihood of coronary artery disease were studied. (99m)Tc-sestamibi studies were acquired with a triple-head scanner equipped with a simultaneous transmission and emission protocol. Four imaging protocols were compared: a 180 degrees acquisition and filtered backprojection reconstruction (FBP), a 360 degrees acquisition and FBP, a 360 degrees acquisition and iterative reconstruction (IT), and a 360 degrees acquisition with IT and AC. Quantitative analysis was performed to evaluate myocardial tracer uniformity for men and women.

Results: 180 degrees, 360 degrees FBP, and 360 degrees IT showed sex differences, with decreased tracer concentration in the anterior wall in women and decreased tracer concentration in the inferior wall in men. AC images showed the greatest uniformity (9.9% coefficient of variation for AC versus 12.5% for IT, P < 0.0001), and no statistically significant differences in uniformity were seen between male and female AC studies.

Conclusion: More uniform myocardial perfusion images were obtained with AC, resulting in images with no differences in uniformity between men and women. These techniques are expected to improve specificity and overall diagnostic accuracy.