by Aubrey C. Patrick
Technology advancements in diagnostic imaging are helping to improve womens heart
disease statistics.
Womens healthcare givers are seeing red these days. But rest
assured, because its all good. Red has become the signature color for several
campaigns to raise Americans awareness of heart disease, especially among women, for
whom it is the leading cause of death. The National Heart, Lung, and Blood Institute and
the American Heart Association co-sponsored National Wear Red Day this past February 6, as
part of The Heart Truth campaign, and First Lady Laura Bush kicked off American Heart
Month on February 4 in a White House ceremony.
The focus of the media blitzto educate about the symptoms and risks of heart
disease and about heart-healthy habitsis no surprise to manufacturers in the imaging
field who provide the technology and products that help reduce morbidity and mortality
among patients. Companies have been working steadily on technological advancements that
will make a difference in the detection and, thus, prognosis of heart disease in women.
Data Is Crucial
We know that women are nine times more likely to die of heart disease than
of breast cancer, says Harry Chesnut of Agfa HealthCares (Ridgefield Park, NJ)
product marketing division. Vendors now recognize that the algorithms that are
appropriate for men are less accurate for women with regard to diagnosis of heart
disease. Hence, along with the new concern about educating the public, manufacturers
are thinking about the issue differently. The technology will not really change, but
the protocols will, he believes.
The Impax cardiac information management system from Agfa Cardiology Products Group
(Milwaukee) allows access to patients images and diagnostic results from various
modalities as well as medical records information. Because the information can be
acquired, manipulated, and shared easily, physicians can make diagnoses and initiate
interventions faster.
Agfa enables the physician to collect information from different devices and
assemble the data without having to make a correlation manually. Doctors need to find
answers quickly, and our expertise is in connecting various systems, Chesnut
explains. With the Agfa workstation, the physician can make searches with a variety
of questions, such as how many patients in a particular population have had ejection
fractions of a certain percentage. The systems templates can highlight problems that
might not be readily evident, and the information is instantly accessible for identifying
various subsets, study protocols, and outcomes.
In addition, cardiologists in particular have been pushing for more evidence-based
medicine, he says, and now they have the tools. The Impax workstation incorporates a
simple reporting system that allows discreet data to be entered without a lot of extra
work, and can then be accessed later for follow-up and research. In the past, vendors
didnt have workable solutions for data, and this hindered research. Only recently
has the technology matured to the point that collecting, storing, sharing, and viewing
images is no longer problematic.
The ultimate challenge, Chesnut says, is to make the workflow optimal for radiologists
and cardiologists, all for the benefit of patients. Because the presentation of
heart disease in women is subtler than in men, we wanted to make the technology better so
that fewer [signs] would be missed, he says. With the higher level of accuracy
and greater automation of todays technologyas well as better management of
images and informationheart disease cases wont fall through the cracks, and
appropriate treatment can be initiated in a more timely manner.
Faster Treatment Enabled by Technology
A recently introduced imaging system, the Innova 3100 from GE Healthcare
(Waukesha, Wis), addresses the need to diagnose and treat the growing number of
cardiovascular cases. GE Healthcare unveiled the system at the annual meeting of the
American College of Cardiology last March.
The system produces images that are sufficiently clear and detailed for physicians to
make accurate diagnoses as well as successfully maneuver catheters, stents, and guide
wires. Flat-panel detector technology produces clear images of the heart, down to the
finest vessels. Not only is the imaging minimally invasive, but it eliminates multiple
procedures by enabling diagnosis and treatment to occur at the same visit.
Because cardiovascular disease affects the entire vascular system, cardiologists
need to see beyond the heart, explains David Handler, general manager of cardiology
marketing for GE Healthcare. In the past, analog-imaging technology was a stumbling
block: You could get a larger field of view, but the image quality was compromised. Now,
with digital technology and the Innova 3100 in particularimage quality is not
compromised at all.
The new generation of Innova technology provides a 30-cm2 field of view, with
flexibility for steep angles yet wide coverage and clear imagingan ideal combination
for interventional and peripheral cardiology. This product can be used even on
larger patients, up to 450 lbs. A doctor using Innova can place a stent in many cases if
it is necessary, instead of having the patient undergo open-heart surgery, Handler
notes. With better images and better data, we now have better management of heart
disease.
Noninvasive, Efficient Imaging with CT
Robb Young sees the advances in CT technology as a huge benefit for women
concerning diagnosis of heart disease. Because women have smaller hearts and, thus,
smaller vessels, the thin scan slices acquired with CT, especially the multislice
scanners, allow more efficient and accurate imaging of the organ, explains Young,
who is cardiac CT product manager for Toshiba America Medical Systems (TAMS of Tustin,
Calif).
TAMS recently introduced its Aquilion 32 CFX CT scanner, which delivers 32 simultaneous
0.5-mm slices in one gantry rotation. The thin slices not only show greater detail and
improve the accuracy of measurement, but theyre also more useful for identification
of plaque and determination of cardiac function. Furthermore, the systems speed
allows data to be acquired twice as fast as with a 16-slice scanner.
CT angiography is a fast, noninvasive alternative to cardiac catheterization, Young
says. The newest CT technology allows us to view the heart vessels
quicklywithin a short breath holdand efficiently, he explains. It
neednt involve hospitalization, so a larger population of patients can be reached.
Research shows that with women in particular, diagnostic catheterization doesnt
always clearly detect disease. In addition, cardiac catheterization has a 0.5% to 1%
mortality rate. CT provides a safer alternativeinstead of insertion of a catheter in
the heart for visualization of the vessels, CT [allows] a needle to be used to inject
contrast material intravenously and less invasively.
Used as a plaque assessment tool, CT can be an independent predictor of heart disease:
A scan as short as 5 to 10 seconds with a 16-slice CT system can determine whether
plaque in the heart vessels is soft (a sign of early-stage disease) or hard.
We need to educate not only the public but also the primary-care physicians about
the symptoms of heart disease in women and how they can differ from those of men,
Young explains. With a better understanding of the disease and the better tools that
are now available, clinicians can more safely look at the heart vessels and make better
decisions about diagnosis and treatment. For almost half of people with heart disease, the
first evidence of it is a heart attack. But CT, as a noninvasive technology, can be used
to quickly assess pain and to detect disease earlier.
The Next Generation of Cardiac Imaging
With regard to the cardiac capabilities of CT, GE Healthcare believes it has made
a breakthrough with its new generation of Light-Speed CT scanners. Recently cleared by the
FDA, the LightSpeed VCT (Volume CT) enables wide-volume scanning as well as
high-resolution images.
This product has significant potential because of the improved image quality,
reliability, and repeatability, notes Scott Schubert, VCT global product manager at
GE Health-care. The challenge with using CT for cardiac imaging is the movement of
the heart and coronary arteries. Thus, two factors are critical in the CT examination:
freezing the heart motion and ensuring high resolution. The LightSpeed VCT
addresses these factors with high-speed imaging, fast temporal resolution, and high
spatial resolution.
In addition to the reduction in scanning time from 20 to 5 seconds, another advantage
of the new system is a reduction in the total amount of contrast medium injected: The
typical dose of 100 cc is reduced by half. This is advantageous for patients who
have kidney disorders or patients who need to immediately undergo interventional cardiac
catheterization [and, hence, further injections], because overall, their contrast burden
will be less, and there is no need to wait for it to diminish between the two
procedures, Schubert explains.
With the variable-speed scanning offered by the LightSpeed technology, the rotation
speed can be adjusted to better match the patients heart rate. In addition,
electrocardiographic input detects the systolic phase and decreases the X-ray dose
accordingly; likewise, the dose is increased during the end-diastolic phase in order to
produce the best image. As a result, the LightSpeed VCT offers a 40% to 50% X-ray dose
reduction over the previous generation of LightSpeed CT scanners.
Clinical testing of the LightSpeed VCT begins this spring, and GE Healthcare expects to
begin delivery of the product later this year.
Aubrey C. Patrick is a contributing writer for Medical Imaging.