Abstract 722: High Reproducibility of Serial Adenosine Single Photon Tomography Myocardial Perfusion Studies: A Quantitative Analysis from the ADVANCE 2 Study
Patients commonly undergo serial adenosine single photon tomography (SPECT) to identify progression of coronary disease or to assess the benefit of anti-ischemic therapies. We sought to define the reproducibility of serial SPECT using quantitative techniques. The ADVANCE 2 study compared image results in patients undergoing adenosine (Ad) SPECT who were then randomized to either a second Ad or to Regadenoson SPECT. A subset of 260 patients had serial Ad SPECT within 4 weeks and form the basis of this analysis. All raw data of gated SPECT images (2 sets/patient) were reconstructed and reoriented in a standard fashion. Quantitative SPECT was performed using a validated program which determined the extent and severity of left ventricular (LV) perfusion defect size (PDS) and the extent of scintigraphic ischemia. PDS severity was defined as mild, moderate or severe based on the relation to normal pixel count activity (>50%, 26–50% and 0–25%, respectively). Quantification was performed blinded to randomization and image sequence. The mean (±SD) perfusion results for the 2 AD SPECT studies are shown in the table⇓ below. Linear regression analysis showed an excellent agreement between the first and second Ad studies when quantifying total (0.99, p<.0001); and ischemic (0.94, p<.0001) LV PDS. The 95% confidence interval for detecting a real change in an individual patient beyond variability was >1% (total PDS), >7% (ischemic PDS) and >4% (scar PDS). When analysis was restricted to the 104 patients with an abnormal Ad1, the 95% confidence intervals were: >9% (total PDS), >9% (ischemic PDS), and >5% (scar PDS). This is the largest series to date defining the high reproducibility of serial Ad SPECT imaging using quantitative polar plot analysis. These data highlight the importance of quantitative analysis when assessing patient changes in clinical practice and when designing clinical trials to assess changes in myocardial perfusion.