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Impact of Absolute Myocardial Blood Flow Quantification on the Diagnostic Performance of PET-Based Perfusion Scans
Laust Dupont Rasmussen1,2,3, Lars Christian Gormsen4, June Anita Ejlersen5
1Department of Cardiology, Gødstrup Hospital, Herning, Denmark (L.D.R., L.L.K., M.B., S.W.).
Insights
Quantitative measurements from Rubidium-82 positron emission tomography (RbPET) improve the identification of obstructive coronary artery disease (CAD). Combining quantitative data with qualitative assessment enhances diagnostic accuracy for obstructive CAD.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Guidelines recommend quantitative Rubidium-82 positron emission tomography (RbPET) for obstructive coronary artery disease (CAD) detection.
- The impact of quantitative RbPET on diagnostic accuracy remains unclear.
- This study aimed to optimize RbPET algorithms for improved obstructive CAD identification.
Purpose of the Study:
- To investigate the optimal RbPET reading algorithm for enhanced identification of obstructive coronary artery disease (CAD).
- To evaluate the diagnostic accuracy of quantitative RbPET measurements in detecting obstructive CAD.
Main Methods:
- 400 patients underwent RbPET and invasive coronary angiography (ICA) with fractional flow reserve (FFR) and quantitative coronary angiography (QCA).
- RbPET quantitative measurements (myocardial blood flow, MBF reserve, transient ischemic dilatation) were added to qualitative summed stress score (SSS).
- Obstructive CAD was defined by ICA-FFR ≤0.80 or >90% diameter stenosis; sensitivity analyses used anatomically severe CAD (>70% diameter stenosis by QCA).
Main Results:
- Stand-alone SSS had 57% sensitivity and 93% specificity; hyperemic MBF showed similar sensitivity (61%) but lower specificity (85%).
- Combining SSS, MBF, and MBF reserve improved discrimination (AUC 0.78 vs. 0.85, P<0.001), yielding 77% sensitivity and 74% specificity.
- For anatomically severe CAD, all measures showed high discrimination (≥0.90), with quantification increasing sensitivity and decreasing specificity.
Conclusions:
- Incorporating quantitative measurements into RbPET analysis significantly improves the identification of obstructive CAD.
- Optimized RbPET algorithms enhance diagnostic accuracy for obstructive coronary artery disease.
Background:
Guidelines propose the inclusion of quantitative measurements from 82Rubidium positron emission tomography (RbPET) to discriminate obstructive coronary artery disease (CAD). However, the effect on diagnostic accuracy is unknown. The aim was to investigate the optimal RbPET reading algorithm for improved identification of obstructive CAD.
Methods:
Prospectively enrolled patients (N=400) underwent RbPET and invasive coronary angiography with fractional flow reserve and quantitative coronary angiography. Quantitative measurements (myocardial blood flow (MBF), MBF reserve, transient ischemic dilatation) by RbPET were step-wisely added to a qualitative assessment by the summed stress score based on their diagnostic accuracy of obstructive CAD by invasive coronary angiography-fractional flow reserve. Prespecified cutoffs were summed stress score ≥4, hyperemic MBF 2.00 mL/g per min, and MBF reserve 1.80, respectively. Hemodynamically obstructive CAD was defined as >90% diameter stenosis or invasive coronary angiography-fractional flow reserve ≤0.80, and sensitivity analyses included a clinically relevant reference of anatomically severe CAD (>70% diameter stenosis by invasive coronary angiography-quantitative coronary angiography).
Results:
Hemodynamically obstructive CAD was present in 170/400 (42.5%) patients. Stand-alone summed stress score showed a sensitivity and specificity of 57% and 93%, respectively, while hyperemic MBF showed similar sensitivity (61%, P=0.57) but lower specificity (85%, P=0.008). With increased discrimination by receiver-operating characteristic curves (0.78 versus 0.85; P<0.001), combining summed stress score, MBF and MBF reserve showed the highest sensitivity of 77% but lower specificity of 74% (P<0.001 for both comparisons). Against anatomically severe CAD, all measures independently yielded high discrimination ≥0.90 with increased sensitivity and lower specificity by additional quantification.
Conclusions:
The inclusion of quantitative measurements to a RbPET read increases in the identification of obstructive CAD.
Registration:
URL: https://www.clinicaltrials.gov; Unique identifier: NCT03481712.
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