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Updated: Jun 8, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Integrated myocardial flow reserve (iMFR) assessment: diffuse atherosclerosis and microvascular dysfunction are more
Jonathan B Moody1, Alexis Poitrasson-Rivière2, Jennifer M Renaud2
1INVIA, LLC, Ann Arbor, MI, USA. jmoody@inviasolutions.com.
Insights
The extent of diffusely impaired myocardial perfusion is a significant predictor of mortality, offering improved risk stratification beyond traditional methods. This finding highlights the prognostic value of integrated myocardial flow reserve (iMFR) in identifying high-risk patients.
Area of Science:
- Cardiology
- Medical Imaging
- Prognostics
Background:
- Revascularization for epicardial stenoses improves symptoms but not survival.
- Conventional ischemia imaging fails to detect diffuse atherosclerosis and microvascular dysfunction.
- Integrated myocardial flow reserve (iMFR) offers a novel approach to differentiate focal from diffuse coronary disease impacts.
Purpose of the Study:
- To evaluate the prognostic value of iMFR in distinguishing the perfusion impact of focal atherosclerosis from diffuse coronary disease.
- To assess the association of novel perfusion measures with mortality risk.
- To determine if iMFR improves risk stratification for mortality.
Main Methods:
- Analysis of a large single-center registry of patients undergoing myocardial perfusion positron emission tomography.
- Utilized Cox proportional hazards modeling to assess mortality risk.
- Evaluated global stress myocardial blood flow (MBF), global myocardial flow reserve (MFR), and iMFR-derived metrics (focal and diffuse impaired perfusion extents).
Main Results:
- In 6867 patients with 3.4-year follow-up, all perfusion measures correlated with death.
- Diffusely impaired perfusion extent (HR 2.65) and global MFR (HR 2.29) were stronger mortality predictors than stress MBF (HR 1.62).
- Focally impaired perfusion extent showed only moderate association with mortality (HR 1.09).
- Diffusely impaired perfusion extent significantly improved risk stratification when added to global MFR (NRI 0.246).
Conclusions:
- The extent of diffusely impaired perfusion is a potent independent marker of mortality risk.
- Diffusely impaired perfusion provides additive prognostic information beyond traditional factors and global MFR.
- Focally impaired perfusion has a less significant association with mortality compared to diffuse impairment.
Background And Aims:
Although treatment of ischemia-causing epicardial stenoses may improve symptoms of ischemia, current evidence does not suggest that revascularization improves survival. Conventional myocardial ischemia imaging does not uniquely identify diffuse atherosclerosis, microvascular dysfunction, or nonobstructive epicardial stenoses. We sought to evaluate the prognostic value of integrated myocardial flow reserve (iMFR), a novel noninvasive approach to distinguish the perfusion impact of focal atherosclerosis from diffuse coronary disease.
Methods:
This study analyzed a large single-center registry of consecutive patients clinically referred for rest-stress myocardial perfusion positron emission tomography. Cox proportional hazards modeling was used to assess the association of two previously reported and two novel perfusion measures with mortality risk: global stress myocardial blood flow (MBF); global myocardial flow reserve (MFR); and two metrics derived from iMFR analysis: the extents of focal and diffusely impaired perfusion.
Results:
In total, 6867 patients were included with a median follow-up of 3.4 years [1st-3rd quartiles, 1.9-5.0] and 1444 deaths (21%). Although all evaluated perfusion measures were independently associated with death, diffusely impaired perfusion extent (hazard ratio 2.65, 95%C.I. [2.37-2.97]) and global MFR (HR 2.29, 95%C.I. [2.08-2.52]) were consistently stronger predictors than stress MBF (HR 1.62, 95%C.I. [1.46-1.79]). Focally impaired perfusion extent (HR 1.09, 95%C.I. [1.03-1.16]) was only moderately related to mortality. Diffusely impaired perfusion extent remained a significant independent predictor of death when combined with global MFR (p < 0.0001), providing improved risk stratification (overall net reclassification improvement 0.246, 95%C.I. [0.183-0.310]).
Conclusions:
The extent of diffusely impaired perfusion is a strong independent and additive marker of mortality risk beyond traditional risk factors, standard perfusion imaging, and global MFR, while focally impaired perfusion is only moderately related to mortality.
