# Stress-rest calf muscle perfusion: a functional diagnostic test for peripheral arterial disease (PAD)

> **NIH NIH R01** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $817,992

## Abstract

Peripheral arterial disease (PAD) affects nearly 8 million people and costs >$21B in the U.S. per year. With
reduced blood supply to their legs, some patients experience calf pain or fatigue with walking. Although PAD
can be reliably detected by a low ankle blood pressure, and anatomic imaging (MRI or CT) of the narrowing
arteries, to select the best treatment approach, we need a non-invasive test to assess calf-muscle function.
 In this project, we propose to use high-resolution magnetic resonance imaging (MRI) to measure blood
perfusion in different groups of calf muscle, and repeat the measurement after a low-load and a high-load
exercise of calf muscle. This stress-rest imaging approach is standard of care for evaluation of coronary artery
disease (CAD), and has never been successfully applied to PAD. Our preliminary results show distinct patterns
of muscle perfusion between healthy and PAD patients, and thus great promise of the technique. In this 4-year
project, we will first refine the perfusion imaging method, verify its reproducibility, and then compare the calf
muscle perfusion measures in PAD patients against healthy age-matched healthy controls. This comparison
will test the feasibility of detecting functional abnormality in PAD patients. After the baseline scans, the PAD
patients will undergo a 12-week supervised exercise therapy, and then a post-therapy MRI scan. Comparison
of the pre- and post-therapy measurement will indicate how the therapy improves the calf-muscle perfusion,
and how this perfusion change correlates with increase in patient’s walking ability.
 The long term goals of this project are to develop an improved diagnostic test for patients with PAD to
predict who will benefit from therapeutic intervention. The stress-rest perfusion studies of calf muscle can be
performed in conjunction with routine peripheral MRA to assess the functional significance of vascular stenosis.
As with the routinely performed cardiac stress imaging methods, improved functional measures of calf
perfusion should also prove useful in the testing and development of improved therapeutic approaches.

## Key facts

- **NIH application ID:** 10043117
- **Project number:** 7R01HL135242-04
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Pradeep Natarajan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $817,992
- **Award type:** 7
- **Project period:** 2019-10-17 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10043117

## Citation

> US National Institutes of Health, RePORTER application 10043117, Stress-rest calf muscle perfusion: a functional diagnostic test for peripheral arterial disease (PAD) (7R01HL135242-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10043117. Licensed CC0.

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