Related Experiment Video
Updated: Mar 26, 2026
Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Blood Oxygenation Level-Dependent CMR-Derived Measures in Critical Limb Ischemia and Changes With Revascularization
Adnan Bajwa1, Roman Wesolowski2, Ashish Patel1
1Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
Insights
Blood oxygenation level-dependent cardiovascular magnetic resonance (BOLD-CMR) can reliably assess lower limb muscle perfusion in critical limb ischemia (CLI) patients. This technique shows promise for detecting improvements after revascularization, aiding clinical management.
Area of Science:
- Cardiovascular Magnetic Resonance Imaging
- Medical Imaging Techniques
- Peripheral Vascular Disease
Background:
- Blood oxygenation level-dependent cardiovascular magnetic resonance (BOLD-CMR) has faced challenges in reproducibility for lower limb perfusion assessment.
- Previous BOLD-CMR methods failed to reliably detect improvements after revascularization in critical limb ischemia (CLI) patients.
Purpose of the Study:
- To develop BOLD-CMR into an objective and reliable clinical tool for measuring calf muscle perfusion.
- To assess the reliability and reproducibility of BOLD-CMR parameters in CLI patients.
Main Methods:
- BOLD-CMR imaging was performed on 3-T MRI in healthy controls (n=22) and CLI patients (n=34).
- Key parameters, signal reduction during ischemia (SRi) and gradient during reactive hyperemia (Grad), were analyzed.
- Perfusion changes post-revascularization were assessed in 12 CLI patients; muscle biopsies (n=28) were analyzed for capillary-fiber ratio.
Main Results:
- BOLD-CMR demonstrated good interuser and interscan reproducibility for Grad and SRi (p < 0.0001).
- CLI patients exhibited significantly lower Grad and SRi compared to controls (p < 0.001).
- Successful revascularization led to significant improvements in Grad (p < 0.0001) and SRi (p < 0.0005), correlating with capillary-fiber ratio.
Conclusions:
- BOLD-CMR is a promising, reliable tool for assessing lower limb muscle perfusion.
- Further clinical trials are warranted to validate BOLD-CMR for routine clinical use in CLI management.
Background:
Use of blood oxygenation level-dependent cardiovascular magnetic resonance (BOLD-CMR) to assess perfusion in the lower limb has been hampered by poor reproducibility and a failure to reliably detect post-revascularization improvements in patients with critical limb ischemia (CLI).
Objectives:
This study sought to develop BOLD-CMR as an objective, reliable clinical tool for measuring calf muscle perfusion in patients with CLI.
Methods:
The calf was imaged at 3-T in young healthy control subjects (n = 12), age-matched control subjects (n = 10), and patients with CLI (n = 34). Signal intensity time curves were generated for each muscle group and curve parameters, including signal reduction during ischemia (SRi) and gradient during reactive hyperemia (Grad). BOLD-CMR was used to assess changes in perfusion following revascularization in 12 CLI patients. Muscle biopsies (n = 28), obtained at the level of BOLD-CMR measurement and from healthy proximal muscle of patients undergoing lower limb amputation (n = 3), were analyzed for capillary-fiber ratio.
Results:
There was good interuser and interscan reproducibility for Grad and SRi (all p < 0.0001). The ischemic limb had lower Grad and SRi compared with the contralateral asymptomatic limb, age-matched control subjects, and young control subjects (p < 0.001 for all comparisons). Successful revascularization resulted in improvement in Grad (p < 0.0001) and SRi (p < 0.0005). There was a significant correlation between capillary-fiber ratio (p < 0.01) in muscle biopsies from amputated limbs and Grad measured pre-operatively at the corresponding level.
Conclusions:
BOLD-CMR showed promise as a reliable tool for assessing perfusion in the lower limb musculature and merits further investigation in a clinical trial.
More Related Videos
Related Concept Videos
01:21Imaging Studies for Cardiovascular System IV: CMRI
01:17Assessment of Diffusion and Perfusion
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this...
01:24Magnetic Resonance Imaging