# PFCS AS CT/ULTRASOUND CONTRAST AGENTS

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 1990 · $116,270

## Abstract

We have shown that perfluorochemicals (PFCs) are effective
ultrasound (US) contrast agents whose echogenic effect on the
liver, spleen, and tumors in animals and man, was detectable by
standard US equipment.  We also showed that perfluoroctylbromide
(PFOB), a radiopaque PFC enhanced the vascular space, liver,
spleen, renal osmotic gradient, and macrophage collections on
computed tomography (CT).  Very stable 100% w/v PFOB emulsion has
been produced with lecithin alone.  PFOB has been approved for
intravenous use in Europe 15 patients have been studied (up to
2.5g/kg) with no side effect attributable to PFOB.  We hope to have
FDA approval in the U.S.A. by late 1987.

PFC concentration (()) in tissues can only be measured with gas
chromatography (GC) of tissue extracts.  While GC is sensitive and
specific to PFC, the % extracted is unknown.  Bromine in PFOB, is
detectable by Neutron Activation Analysis (NAA).  It showed that
extraction was less than 50%, varied for different organs, and
decreased over time for the same organ biasing pharmacokynetics
data.  We wish to utilize NAA to evaluate the efficacy of several
extraction techniques to optimize our extraction, correct our data,
explain discrepancies between CT and tissue (PFOB), and since this
problem is not unique to PFOB, provide data to those that must
utilize extracts.

Seeking a technique to estimate (PFOB) in vivo which allows for
longitudinal studies and tissue (PFOB) mapping, we constructed a
small CT phantom which was calibrated, and validated for (PFOB) up
to 70mg/g.  (PFOB) determined with CT and high correlation with NAA
(Y-1.01X-4, r-0.96).  We propose to calibrate the phantom to higher
(PFOB), test its accuracy in assessing biodistribution and
elimination in live rabbits, and construct, calibrate, and validate
a larger phantom for human use.

The delayed echogenic effect of PFC's (24-48hrs) is thought to be
impractical.  We have recently observed that PFOB enhances tissues
within minutes after infusion.  We wish to prove this observation
by comparing relative echogenicity of a vascular tissue (renal
cortex and liver) to a relatively hypovascular tissues (Vx2 tumor),
as well as an implanted phantom over time and at different PFOB
dosages (1-5g/kg).

We showed in vitro utilizing PFOB and its vehicle emulsion that
PFOB is a potent additive to a lecithin emulsion that markedly
affects acoustic properties at 5MHz.  We wish to extend these
experiments to other frequencies and to tissues to better
understand the mechanisms of PFOB tissue enhancement.

## Key facts

- **NIH application ID:** 3174381
- **Project number:** 5R01CA036799-06
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **SAM.gov UEI:** UYTTZT6G9DT1
- **Principal Investigator:** ROBERT F MATTREY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $116,270
- **Award type:** 5
- **Project period:** 1983-08-01 → 1993-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3174381

## Citation

> US National Institutes of Health, RePORTER application 3174381, PFCS AS CT/ULTRASOUND CONTRAST AGENTS (5R01CA036799-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3174381. Licensed CC0.

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