Novel Diagnostic Tool Detects Life-Threatening Infections Faster Than Standard Nuclear Imaging Tests

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Source:   Cedars-Sinai Medical Center (http://www.csmc.edu/)

Date:   Posted 6/19/2002

Novel Diagnostic Tool Detects Life-Threatening Infections Faster Than

Standard Nuclear Imaging Tests

LOS ANGELES, CA -- Researchers at Cedars-Sinai Medical Center have found

that a novel imaging agent detects life-threatening infections and

inflammation in patients more rapidly than the standard nuclear medicine

imaging tests typically used for this purpose. The imaging agent may

eliminate the need for additional tests and reduce the risk of exposure

involved in handling blood samples taken when additional clarification is

needed to identify the infection.

The study, presented at the 49th Annual Meeting of the Society of Nuclear

Medicine, sought to determine whether the agent, a non-invasive

radiopharmaceutical recently FDA approved for the detection of lung cancer,

was effective in identifying the presence of infection or inflammation. The

investigators found that the imaging agent, called Tc 99m Depreotide

detected the source of the infection in all patients studied three hours

after they received the agent. Infection and inflammations included

pneumonia, infections of bone, kidney, lining of the heart, gallbladder,

skin and joint prosthesis.

" Our results show that a Depreotide scan identified the source of infection

in all patients who had successfully undergone other types of nuclear

imaging tests to determine the cause of infection, " said Alan Waxman, M.D.,

the lead author of the study and the Director of Nuclear Medicine and

Co-Chairman of Imaging at Cedars-Sinai Medical Center. " In short, Depreotide

enabled us to determine the presence of infection about three hours after

the patient underwent a Depreotide scan when it usually takes as long as 24

to 48 hours to get results. This means that medical decisions can be made

much more rapidly and accurately when a patient's life may be at stake. "

Typically, radiologists use nuclear imaging tests such as labeled white

blood cells or other radio tracers to help identify the type and source of

infection when patients present with fever or other signs of infection.

These tests detect infection by slowly concentrating in areas where white

blood cells have collected to fight infection. The detection of abnormality

often depends on the concentration of the tracer over many hours or days

before the abnormalities are visualized. Test results can take from 24 to 48

hours and require laboratory technicians to handle blood products, which can

expose them to HIV or AIDS.

The imaging agent, Depreotide, is a small synthetic peptide that works by

attaching to proteins called somatostatin receptors, which are present on

lung cancer cell surfaces. And, because a large number of these receptors

are present on lung cancer cells, the agent concentrates on the cells and

provides clear images of the tumor. But some infection and inflammatory

processes also involve the expression of somatostatin receptors on cell

surfaces, leading Dr. Waxman and his research team to examine whether the

agent could provide clear images of the infection.

To determine whether Depreotide could detect infection more rapidly and

accurately than traditional imaging tests, 19 patients with 21 previously

identified sources of infection/inflammation were given an injection of

Tc-99m Depreotide and underwent whole body imaging scans with a nuclear

medicine camera two hours later. Infection/inflammation was detected in all

patients studied, sometimes more accurately than other tests, including CT

scans.

The investigators found that Depreotide was able to detect the source of

infection in all or 100 percent of the patients with previously identified

infections within a three-hour time period.

" Our results suggest that this agent is capable of detecting infections

within three hours after receiving an injection of Depreotide without

handling blood products or having to perform extra imaging studies, " said

Dr. Waxman.

This study was supported by a grant from Berlex Laboratories, Inc. Further

studies will investigate the type of infection that is best characterized by

the Depreotide agent.

Cedars-Sinai Medical Center is one of the largest nonprofit academic medical

centers in the Western United States. For the fifth straight two-year

period, Cedars-Sinai has been named Southern California's gold standard in

health care in an independent survey. Cedars-Sinai is internationally

renowned for its diagnostic and treatment capabilities and its broad

spectrum of programs and services, as well as breakthrough in biomedical

research and superlative medical education. Named one of the 100 " Most

Wired " hospitals in health care in 2001, the Medical Center ranks among the

top 10 non-university hospitals in the nation for its research activities.