# NON-CONTRAST-ENHANCED PERIPHERAL MR ANGIOGRAPHY

> **NIH NIH R01** · CASE WESTERN RESERVE UNIVERSITY · 2020 · $369,070

## Abstract

Project Abstract
In patients with vascular disease, clear delineation of the arteries of interest is essential for diagnosis
and treatment planning. While a number of angiography techniques are available nowadays, non-
contrast-enhanced (NCE) magnetic resonance angiography (MRA) is considered a highly promising
modality due to non-invasiveness as opposed to digital subtraction angiography (DSA), and the
absence of side effects unlike computerized tomography (involving ionizing radiation) and gadolinium-
contrast-enhanced MRA (involving the risk of nephrogenic systemic fibrosis). As such, many NCE
MRA methods have been explored in the past decades, yet are still at some distance from solid
clinical acceptance due to issues such as limited angiographic coverage and spatial resolution, and
long scan time (particularly when multiple acquisitions are needed).
This project will focus on novel NCE MRA methods which achieve high vessel contrast, high spatial
resolution in all 3 dimensions and large angiographic coverage in short scan time. At the core of the
proposed method is velocity-selective (VS) magnetization preparation which generates angiographic
contrast by suppressing background materials while preserving arterial blood based on their velocity.
Due to spatially non-selective nature, VS preparation can be combined with 3D encoding with large
FOV and high spatial resolution in all three dimensions unlike inflow-based approaches such as time-
of-flight. Also, VS preparation generates positive angiographic contrast directly from single acquisition,
as opposed to existing flow-sensitive approaches that require two acquisitions to be subtracted. We
will first develop VS excitation pulse sequences which are robust to potential variation in B0 and B1
field as well as eddy current of VS gradient. Areas of investigation will include incorporation of multiple
refocusing pulses, Malcom-Levitt phase cycling, and two successive VS preparations. Exploiting the
sparsity of background-suppressed image of VS-MRA, we will achieve high-rate scan acceleration by
combining compressed sensing with parallel imaging reconstruction. While the proposed VS-MRA is
applicable for diverse vascular territories, this project will focus on peripheral angiography and
cerebral angiography as representative clinical applications. For each of the two applications, we will
optimize VS-MRA pulse sequences by selecting optimal number of refocusing pulses and type of
refocusing composite pulse based on estimates of B0 and B1 offsets. Using the optimized protocol,
lastly, diagnostic performance will be evaluated in patients with x-ray angiography as the reference.

## Key facts

- **NIH application ID:** 9936056
- **Project number:** 5R01HL135500-04
- **Recipient organization:** CASE WESTERN RESERVE UNIVERSITY
- **Principal Investigator:** Sanjay Rajagopalan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $369,070
- **Award type:** 5
- **Project period:** 2017-04-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9936056

## Citation

> US National Institutes of Health, RePORTER application 9936056, NON-CONTRAST-ENHANCED PERIPHERAL MR ANGIOGRAPHY (5R01HL135500-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9936056. Licensed CC0.

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