Abstract 12085: Quantitative Adenosine Stress Myocardial Perfusion Computed Tomography: A 4-Fold Radiation Dose Reduction Using a Time Adaptive Filter (TAF)
Introduction: Integration of myocardial perfusion (MP) computed tomography into routine clinical practice is limited by high radiation dose. However, reduced dose leads to increased image noise and exacerbation of artifacts. Existing techniques can reduce image noise, but may compromise quantitative accuracy of MP estimates. This study aimed to evaluate a novel time adaptive filter (TAF) that we developed, which reduces image noise yet maintains accuracy of MP quantitation.
Methods: Six pigs (35-42 kg) underwent MP imaging with a dual-source CT scanner at 80 kVp and both 360 (reference dose, REF) and 90 (low dose, LOW) mAs, after intracoronary adenosine injections (100 ug/kg/min) into the left anterior descending (LAD) coronary artery. Contrast medium was injected through a catheter in the superior vena cava (0.33 ml/kg over 2 s). Time attenuation curves (TAC), generated for the left ventricular (LV) chamber and the perfused LAD territory, were fitted by gamma variates for estimation of MP.
Results: Mean heart rate and arterial pressure during REF scans (91.2 ± 13.2 bpm and 71.3 ± 14.0 mmHg, respectively) remained unchanged during LOW scans. The average image noise in the LAD territory observed using REF increased with LOW, but was restored in LOW+TAF (17.1 ± 1.4, 33.2 ±5.5, and 13.9 ± 2.5 HU, respectively). TACs showed excellent agreement between REF and LOW+TAF (Figure). MP parameter estimates demonstrated a mean difference of 8.5% (range 0.9-15.7%). Estimated MP values derived from the REF and LD+TAF data were similar (2.08±0.62 and 2.02 ±0.53 ml/g/min, respectively, p = NS).
Conclusion: Low dose data processed with the TAF algorithm reduced image noise 2 to 3-fold, yet yielded perfusion estimates that were not significantly different from the reference dose protocol. This technique may make myocardial perfusion computed tomography clinically practical.
- © 2011 by American Heart Association, Inc.