Splenic switch-off in three-dimensional adenosine stress cardiac magnetic resonance perfusion for differentiating true-negative from potentially false-negative studies identified by fractional flow reserve

Figures

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  Fig. 1. Patient inclusion flowchart showing initial enrollment, exclusions, and final study population. The number of patients with and without CAD (based on FFR ≤ 0.80) and their respective SSO status (present or absent) are also presented. CAD coronary artery disease, FFR fractional flow reserve, SSO splenic switch-off, 3D three-dimensional, CMR cardiovascular magnetic resonance

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  Fig. 2. Example of splenic switch-off (SSO) and signal intensity (SI) assessment. Representative first-pass perfusion images at peak myocardial signal intensity from a patient with splenic switch-off (SSO+) during 3D adenosine stress perfusion (A), and the corresponding rest perfusion image (B). Images (C) and (D) show another patient with absent splenic switch-off (SSO−) during adenosine stress and rest, respectively. Corresponding SI-time curves display: splenic mean (blue solid line) and maximum (orange solid line) SI, left ventricular (LV) blood pool mean SI (purple dotted line), and myocardial mean SI (green solid line). SI values are normalized to the peak LV blood pool signal and are given in arbitrary units (a.u.).While the anterolateral wall in panel C appears relatively hypointense, the patient had no perfusion defect on clinical read and no flow-limiting lesion on FFR. Furthermore, the green SI curve demonstrates similar myocardial signal enhancement between stress and rest, indicating no quantitative evidence of ischemia. FFR fractional flow reserve.

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  Fig. 3. Markers of stress adequacy in CMR. This diagram depicts the distribution of true-negative and false-negative CMR perfusion results among negative CMR studies, stratified by the presence or absence of different stress adequacy markers, with invasive FFR serving as the reference standard. The following thresholds were used to define an adequate stress response: SI ratio stress-to-rest of spleen ≤0.32, SI ratio spleen-to-myocardium at stress ≤0.38, heart rate increase ≥10 bpm, and blood pressure decrease ≥10 mmHg. CMR cardiac magnetic resonance, FFR fractional flow reserve, HR heart rate, RR blood pressure, SI signal, SSO splenic switch-off between stress and rest

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  Fig. 4. Predictive performance of signal intensity ratios for visual splenic switch-off. Receiver operating characteristic (ROC) curves demonstrating the ability of quantitative splenic signal intensity ratios to predict visually assessed splenic switch-off (SSO). Both the stress-to-rest signal intensity ratio of the spleen (blue) and the splenic-to-myocardial signal intensity ratio under stress (purple) showed excellent agreement with visual SSO status. These findings support the use of objective markers to complement or potentially replace visual evaluation in the absence of rest images. cvAUC cross-validated area under the curve, CMR cardiovascular magnetic resonance, FFR fractional flow reserve

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  Fig. 5. Ability of signal intensity ratios for identifying true-negative CMR studies. ROC curves for evaluating the ability of quantitative splenic perfusion parameters to discriminate between true-negative and potentially false-negative CMR perfusion studies (using invasive FFR as the reference standard). Both the stress-to-rest signal intensity ratio of the spleen (blue) and the splenic-to-myocardial ratio at stress (purple) showed good predictive ability in identifying true-negative studies, indicating their potential role as objective markers of stress adequacy among negative CMR exams. cvAUC cross-validated area under the curve, CMR cardiovascular magnetic resonance, FFR fractional flow reserve, ROC receiver operating characteristic