Quantitative assessment of myocardial perfusion abnormality on SPECT myocardial perfusion imaging is more reproducible than expert visual analysis

Abstract

Background Current guidelines of Food and Drug Administration for the evaluation of SPECT myocardial perfusion imaging (MPI) in clinical trials recommend independent visual interpretation by multiple experts. Few studies have addressed whether quantitative SPECT MPI assessment would be more reproducible for this application. Methods and Results We studied 31 patients (age 68 ± 13, 25 male) with abnormal stress MPI who underwent repeat exercise (n = 11) or adenosine (n = 20) MPI within 9-22 months (mean 14.9 ± 3.8 months) and had no interval revascularization or myocardial infarction and no change in symptoms, stress type, rest or stress ECG, or clinical response to stress on the second study. Visual interpretation per FDA Guidance used 17-segment, 5-point scoring by two independent expert readers with overread of discordance by a third expert, and percent myocardium abnormal was derived from normalized summed scores. The quantitative magnitude of perfusion abnormality was assessed by the total perfusion deficit (TPD), expressing stress, rest, and ischemic perfusion abnormality. High linear correlations were observed between visual and quantitative size of stress, rest, and ischemic defects (R = 0.94, 0.92, 0.84). Correlations of two tests were higher by quantitative than by visual methods for stress (R = 0.97 vs R = 0.91, P = 0.03) and rest defects (R = 0.94 vs R = 0.82, P = 0.03), respectively, and statistically similar for ischemic defects (R = 0.84 vs R = 0.70, P = ns). Conclusions In stable patients having serial SPECT MPI, quantification is more reproducible than visual for magnitude of perfusion abnormality, suggesting its superiority for use in randomized clinical trials and monitoring the effects of therapy in an individual patient.

Automated assessment of serial SPECT myocardial perfusion images

“…8 Further, Berman et al predict that automated methods should be superior to visual methods in randomized clinical trials and when monitoring the effects of therapy in an individual patient. 8 Despite the limitations of the study, we concur with the overall conclusions, and our own experience is in accordance with the findings.…”

“…8 Further, Berman et al predict that automated methods should be superior to visual methods in randomized clinical trials and when monitoring the effects of therapy in an individual patient. 8 Despite the limitations of the study, we concur with the overall conclusions, and our own experience is in accordance with the findings. The limitations of the study are partly addressed by the authors and include the small sample size (only 25 patients with ischemia), the long time intervals between the two studies, and the fact that all studies were from same institution.…”

“…8 Assuming one uses an automated method for serial testing in a clinical trial, what type of patients should be recruited given these thresholds, or alternatively, are these thresholds applicable to all patients regardless of size of baseline abnormality? One option is to express the change from absolute to relative percentages as is often done in large trials in acute myocardial infarction or acute coronary syndromes.…”

It’s not all in the numbers

“…20 Compared with visual assessment alone, quantitation improves interpretive reproducibility. 21,22 Robust diagnostic accuracy is consistently shown, 15,23,24 with some studies reporting higher accuracy than visual analysis. 19,25 Quantitation should improve risk stratification, although there are few publications to date in this regard.…”

Validation of Automated Quantification of Myocardial Perfusion Single-Photon Emission Computed Tomography Using Heart Score View in Patients With Known or Suspected Coronary Artery Disease

“…To overcome these limitations, several software packages for automated quantification such as Quantitative Perfusion SPECT (QPS; version 7.2) (Cedars-Sinai Medical Center, USA) have been developed and commonly used to optimise reproducibility and improve accuracy. [4][5][6] Recently, a new software package called Heart Score View (HSV; version 1.5) (Nihon Medi-Physics, Japan) was developed in Japan. [7][8][9] In the current study, we compared the scoring results of myocardial perfusion among visual analysis, QPS and HSV in patients with known or suspected coronary artery disease.…”