System offers new blood visualization capabilitiesBlood is seldom viewed directly by radiologists. Contrast media block x-rays, creating shadow images of blood vessels on arteriograms, the gold standard for evaluating vascular pathology.
System offers new blood visualization capabilities
Blood is seldom viewed directly by radiologists. Contrast media block x-rays, creating shadow images of blood vessels on arteriograms, the gold standard for evaluating vascular pathology. Conventional ultrasound detects motion, not blood, painting flow as red or blue swaths to indicate direction. Now GE Medical Systems claims to have developed a new way to directly image blood flow, as well as the walls of blood vessels. And the result, according to radiologists who have tried the new technology, could be faster and more accurate diagnoses.
The Milwaukee company unveiled this new capability on April 29 in New York City as part of the latest annual upgrade to its flagship Logiq 700 platform. Dubbed Logiq 700 Expert, the new system is built around GEs coded excitation process, introduced last year (SCAN 5/13/98). This technique sculpts the ultrasound beam into tight pulses fired rapidly into the body. Whereas competing ultrasound systems use separate techniquesgray-scale imaging and Doppler flowto create a combined image of vasculature and surrounding tissues, Logiq 700 Expert simultaneously visualizes blood and surrounding anatomy.
Luminaries at about a dozen institutionseight in the U.S., two in Germany, and one each in Japan and Canadahave already taken the new Logiq product for a spin. GE executives expect interest in the new system to build quickly, predicting that it will be installed at more than 500 hospitals around the world by the end of the year. Thats a tall order, since commercial sales will not begin until June. The company plans to price the new product competitively with other premium scanners.
Logiq 700 Expert uses a technique called b-flow to characterize the movement of blood and the surrounding anatomy, including the walls of arteries and veins. The Expert system, the latest in a series of annual upgrades released by GE for the Logiq 700, also includes an enhanced harmonic imaging capability, called coded harmonics.
These two new technologies may extend the clinical reach of ultrasound in the diagnosis of stroke, as well as soft-tissue abnormalities, including cancer. Enhanced diagnoses, resulting from enhanced resolution, may be possible from studies of anatomical areas including the liver, kidneys, thyroid, and breast, as well as the fetus.
The Logiq 700 Expert series is geared toward using ultrasound for more preventive care early as opposed to reactive care later, said Omar Ishrak, general manager of global ultrasound for GE.
Ishrak specifically addressed the visualization of plaque in blood vessels during its early stages of development. Diagnosis of preclinical conditions might allow treatment before the plaque breaks off and migrates to the brain, causing stroke, he said.
The ability of Expert to detect early signs of vascular pathology was noted by Dr. Thomas Stavros, medical director of ultrasound and noninvasive vascular services at Swedish Medical Center in Denver. In studies conducted on Logiq 700 Expert over the past four months, Stavros reported seeing sinewy, web-like structures in blood vessels. These structures, which indicate a condition called fibromuscular dysplasia, may predispose patients to stroke.
One patient, who had nonspecific symptoms of dizziness and light-headedness, showed a sign of this conditionswirling bloodusing color Doppler. A soft finding of this type requires verification, according to Stavros, usually with x-ray arteriography, an invasive procedure. Using Logiq 700 Expert, however, Stavros was able to clearly demonstrate two membranes and definitively diagnose the patient with fibromuscular dysplasia, avoiding arteriography.
This is an example of how b-flow enabled us to make a more specific diagnosis, he said. With more specific findings, we can empower the patient to make decisions.
Stavros reported seeing ulcerated plaque and blood-vessel irregularities in other patients, which would have escaped detection without Expert. Specifically, he saw flow within the plaque ulcers, a capability that goes beyond even the gold standard of x-ray arteriography.
Dr. Edward Lyons, a professor of radiology and ob/gyn at the Health Sciences Centre in Winnipeg, Canada, reported seeing blood flow within the walls of the blood vessels themselves. When visualizing carotid and renal arteries, Lyons also demonstrated irregularities on the wall surface, as well as calcifications within the plaque.
We can get a better assessment of anatomy and physiology when we see the dynamics, he said.
The clinical significance of this new visualization technique remains to be determined. One possibility is to use patterns of dynamic flow to identify problems with grafted blood vessels, according to Lyons.
Both radiologists were impressed with the systems new coded harmonics capability. Stavros demonstrated unique capabilities of this technology for evaluating suspicious breast lesions, noting that definitive diagnosis100% certaintyis possible when evaluating complex cysts, but not when using conventional ultrasound. Complex cysts are cluttered with debris and, therefore, have a small chance of harboring cancer, he said. With coded harmonics, he was able to completely rule out cancer in seven of 10 patients.
I was able to move from pretty sure the lesion was benign to sure it was benign, he said.
There are other upgrades to Logiq 700 Expert, albeit none as impressive. These are aimed primarily at improving productivity. One, called automatic optimization, adds the ability to automatically enhance images with a single keystroke. Another speeds the 3-D reconstruction of images, while improving the quality of these images. Additionally, a new high-frequency probe, called M7C, offers improved near- and far-field imaging.