# Vascular CT contrast agent development

> **NIH NIH R44** · NEXTRAST, INC. · 2022 · $821,821

## Abstract

Project Summary / Abstract
Our long-term goal is to revolutionize the effectiveness of vascular imaging by computed tomography (CT) for
millions of Americans. Contrast-enhanced CT is the modality of choice for imaging many forms of vascular
disease due to ease of use and wide availability. Unfortunately, currently available CT contrast agents are
severely limited by poor vascular enhancement, particularly in large-to-obese patients because of beam
hardening and loss of signal at the high kVp settings needed to image this patient population. Moreover, these
so-called “extravascular extracellular” small-molecule agents equilibrate rapidly between the intravascular and
interstitial fluid, and hence provide a “washed out” appearance of critical venous structures. Considering that
obesity is a major risk factor for cardiovascular disease and is increasing in prevalence, a transformative
contrast agent with improved imaging capabilities is urgently needed for this poorly served population. Patients
with an allergy to iodine are without alternative CT contrast options. Furthermore, iodine contrast is poorly
distinguished from vascular calcifications and metal-containing implants such as stents, despite the advent of
dual energy CT.
 We propose to develop a safe blood pool tantalum nanoparticle contrast agent (TaCZ) to address these
urgent unmet clinical needs. Our prior work showed excellent tolerance to TaCZ in four animal species, even
up to 6X intended clinical dose and with repeat dosing. TaCZ shows superior X-ray signal in vivo and in vitro,
even in simulated large body habitus. TaCZ shows the unique property of having both a blood pool distribution
yet, surprisingly, rapid renal excretion and minimal biological retention on par with clinical iodinated contrast
agents. With advanced metal artifact reduction algorithms for CT imaging, TaCZ is unlike iodinated agents in
that it retains excellent signal, which makes it ideal for imaging post-surgical or trauma patients. The duration
of intense vascular enhancement is over 5 minutes, unlike for iodinated agents’ 5 to 10 seconds, which
minimizes risk for error and mis-timing at vascular imaging. Profoundly, TaCZ may be used simultaneously
with iodine contrast agents as different “colors” at dual energy CT imaging to generate unprecedented
information-rich co-registered color contrast CT images with a single 5 second pass of the scanner. In our
project proposal, we will define processes and specifications for scaled-up TaCZ synthesis for tight size
distribution. Preclinical toxicity data will be extended to include maximum feasible intraperitoneal and GLP
maximum intravenous repeat dose testing to enable FDA-IND. Then first-in-human Clinical Phase 1 testing will
assess safety and efficacy in normal and obese individuals. At the conclusion of this project, we will have
validated data suitable for the Clinical Phase 2 and 3 human trials required for FDA-NDA approval and
commercial use of this transformativ...

## Key facts

- **NIH application ID:** 10479986
- **Project number:** 5R44HL152877-03
- **Recipient organization:** NEXTRAST, INC.
- **Principal Investigator:** Michael A Davis
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $821,821
- **Award type:** 5
- **Project period:** 2020-09-01 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10479986

## Citation

> US National Institutes of Health, RePORTER application 10479986, Vascular CT contrast agent development (5R44HL152877-03). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10479986. Licensed CC0.

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