Quantitative myocardial perfusion in coronary artery disease: A perfusion mapping study

Knott, Kristopher; Camaioni, Claudia; Ramasamy, Anantharaman; Augusto, João; Bhuva, Anish; Xue, Hui; Manisty, Charlotte; Hughes, Rebecca; Brown, Louise A.; Amersey, Rajiv; Bourantas, Christos V.; Kellman, Peter; Plein, Sven; Moon, James

doi:10.1002/jmri.26668

Cited by 44 publications

(34 citation statements)

References 34 publications

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“…Initial validation results (e.g. against PET and coronary angiography) are good (20,21) and inter-subject repeatability is similar to the published PET literature. (22,23).…”

Section: Introductionsupporting

confidence: 70%

Quantitative Myocardial Perfusion in Fabry Disease

Knott

Augusto

Nordin

et al. 2019

Circ: Cardiovascular Imaging

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Background: Fabry disease (FD) is an X-linked lysosomal storage disease resulting in tissue accumulation of sphingolipids. Key myocardial processes that lead to adverse outcomes in FD include storage, hypertrophy, inflammation and fibrosis. These are quantifiable by multi-parametric Cardiovascular Magnetic Resonance (CMR). Recent developments in CMR perfusion mapping allow rapid in-line perfusion quantification permitting broader clinical application, including the assessment of microvascular dysfunction. We hypothesized that microvascular dysfunction in FD would be associated with storage, fibrosis and oedema. Methods: A prospective, observational study of 44 FD patients (49 years, 43% male, 24 (55%) with left ventricular hypertrophy (LVH)) and 27 healthy controls with multi-parametric CMR including vasodilator stress perfusion mapping. Myocardial blood flow (MBF) was measured and its associations with other processes investigated. Results: Compared to LVH-FD, LVH+ FD had higher LV ejection fraction (73% vs 68%), more LGE (85% vs 15%) and a lower stress MBF (1.76 vs 2.36ml/g/min). The reduction in stress MBF was more pronounced in the subendocardium than subepicardium. LVH-FD had lower stress MBF than controls (2.36 vs 3.00ml/g/min, p=0.002). Across all FD, LGE and low native T1 were independently associated with reduced stress MBF. On a per-segment basis stress MBF was independently associated with wall thickness, T2, ECV and LGE. Conclusions: FD patients have reduced perfusion, particularly in the subendocardium with greater reductions with LVH, storage, edema and scar. Perfusion is reduced even without LVH suggesting it is an early disease marker. Clinical perspective Fabry disease (FD) is a slowly progressive multisystem storage disease. Progressive cardiac involvement is the primary cause of premature death. Therapy is available but expensive. Myocardial phenotype development and pathways is not well understood and the impact of treatment and the timing of initiation is uncertain. Recently, cardiovascular magnetic resonance has begun to unravel phenotype development because, as well as hypertrophy and fibrosis (using late gadolinium enhancement), storage can now be measured (using T1 mapping) and edema/inflammation (using T2 mapping). Microvascular dysfunction is also thought also to play a role. CMR perfusion mapping can now quantify thisboth concurrently with the other assessments and without using ionizing radiation, more easily permitting the assessment of early disease. We performed multi-parametric CMR in FD including perfusion mapping. Compared to healthy volunteers, patients with FD had reduced stress myocardial blood flow (MBF). This occurred even before hypertrophy. It was most marked subendocardially, was worse when there was storage and, regionally, where there was fibrosis. This implies that microvascular dysfucntion is an early disease feature and could contribute to the progression from storage to fibrosis (and hence heart failure and arrhythmia). Because it may relate to endothelial rather t...

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“…Initial validation results (e.g. against PET and coronary angiography) are good (20,21) and inter-subject repeatability is similar to the published PET literature. (22,23).…”

Section: Introductionsupporting

confidence: 70%

Quantitative Myocardial Perfusion in Fabry Disease

Knott

Augusto

Nordin

et al. 2019

Circ: Cardiovascular Imaging

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“…This has led to myocardial perfusion examinations only being routinely performed in highly experienced centres. Quantitative perfusion analysis has been proposed as a more reproducible and user-independant alternative to the visual assessment and has been shown to have a good diagnostic accuracy and prognostic value (Hsu et al., 2018; Knott et al., 2019; Sammut et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

Hierarchical Bayesian myocardial perfusion quantification

Scannell

Chiribiri

Villa

et al. 2020

Medical Image Analysis

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Purpose: Tracer-kinetic models can be used for the quantitative assessment of contrast-enhanced MRI data. However, the model-fitting can produce unreliable results due to the limited data acquired and the high noise levels. Such problems are especially prevalent in myocardial perfusion MRI leading to the compromise of constrained numerical deconvolutions and segmental signal averaging being commonly used as alternatives to the more complex tracer-kinetic models.Methods: In this work, the use of hierarchical Bayesian inference for the parameter estimation is explored. It is shown that with Bayesian inference it is possible to reliably fit the two-compartment exchange model to perfusion data. The use of prior knowledge on the ranges of kinetic parameters and the fact that neighbouring voxels are likely to have similar kinetic properties combined with a Markov chain Monte Carlo based fitting procedure significantly improves the reliability of the perfusion estimates with compared to the traditional least-squares approach. The method is assessed using both simulated and patient data. Results:The average (standard deviation) normalised mean square error for the distinct noise realisations of a simulation phantom falls from 0.32 (0.55) with the least-squares fitting to 0.13 (0.2) using Bayesian inference. The assessment of the presence of coronary artery disease based purely on the quantitative MBF maps obtained using Bayesian inference matches the visual assessment in all 24 slices. When using the maps obtained by the least-squares fitting, a corresponding assessment is only achieved in 16/24 slices.Conclusion: Bayesian inference allows a reliable, fully automated and user-independent assessment of myocardial perfusion on a voxel-wise level using the two-compartment exchange model.

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“…Recent advances in CMR perfusion mapping now permit high-resolution, pixel-wise myocardial blood flow (MBF) quantification automatically and inline at the scanner (figures 1 and 2) 15 using the Gadgetron software framework 16. In suspected ischaemic heart disease the technique has been validated using PET, angiography and invasive fractional flow reserve (FFR) 17–19. Perfusion mapping has also provided insights into the disease process in Fabry disease 20.…”

Section: Introductionmentioning

confidence: 99%

Inline perfusion mapping provides insights into the disease mechanism in hypertrophic cardiomyopathy

Camaioni

Knott

Augusto

et al. 2019

Heart

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ObjectiveIn patients with hypertrophic cardiomyopathy (HCM), the role of small vessel disease and myocardial perfusion remains incompletely understood and data on absolute myocardial blood flow (MBF, mL/g/min) are scarce. We measured MBF using cardiovascular magnetic resonance fully quantitative perfusion mapping to determine the relationship between perfusion, hypertrophy and late gadolinium enhancement (LGE) in HCM.Methods101 patients with HCM with unobstructed epicardial coronary arteries and 30 controls (with matched cardiovascular risk factors) underwent pixel-wise perfusion mapping during adenosine stress and rest. Stress, rest MBF and the myocardial perfusion reserve (MPR, ratio of stress to rest) were calculated globally and segmentally and then associated with segmental wall thickness and LGE.ResultsIn HCM, 79% had a perfusion defect on clinical read. Stress MBF and MPR were reduced compared with controls (mean±SD 1.63±0.60 vs 2.30±0.64 mL/g/min, p<0.0001 and 2.21±0.87 vs 2.90±0.90, p=0.0003, respectively). Globally, stress MBF fell with increasing indexed left ventricle mass (R2 for the model 0.186, p=0.036) and segmentally with increasing wall thickness and LGE (both p<0.0001). In 21% of patients with HCM, MBF was lower during stress than rest (MPR <1) in at least one myocardial segment, a phenomenon which was predominantly subendocardial. Apparently normal HCM segments (normal wall thickness, no LGE) had reduced stress MBF and MPR compared with controls (mean±SD 1.88±0.81 mL/g/min vs 2.32±0.78 mL/g/min, p<0.0001).ConclusionsMicrovascular dysfunction is common in HCM and associated with hypertrophy and LGE. Perfusion can fall during vasodilator stress and is abnormal even in apparently normal myocardium suggesting it may be an early disease marker.

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Quantitative myocardial perfusion in coronary artery disease: A perfusion mapping study

Cited by 44 publications

References 34 publications

Quantitative Myocardial Perfusion in Fabry Disease

Quantitative Myocardial Perfusion in Fabry Disease

Hierarchical Bayesian myocardial perfusion quantification

Inline perfusion mapping provides insights into the disease mechanism in hypertrophic cardiomyopathy

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