Researchers at the Kansas University Medical Center (KUMC) have designed new ultrasound technology that enables them to measure the stiffness of tissue masses deep beneath the skin.
Stiff or unusually firm tissue can be a primary indicator of abnormalities and even disease, but physicians must often rely on their own abilities to feel masses in order to examine them.
"It's not very sensitive in some cases," said Timothy Hall, PhD, a professor of radiology and director of the Image Science and Technology lab at KUMC. "Palpation is only sensitive to things close to the surface that are large and stiff compared to surrounding tissue."
Hall and his colleagues have developed a computer imaging program that uses ultrasound imaging to measure the stiffness and size of tissue several centimeters beneath the surface and as small as a few millimeters in diameter. More importantly, preliminary studies indicate that this technology, called palpation imaging, can identify and differentiate between tissue masses.
"The stiffness of different kinds of lesions appears to be unique," Hall said. "From our experience so far, we can often tell from our imaging alone what type of lesion it is-whether it's carcinoma, cyst or fibroadenoma."
Identification at this stage could tell the physician whether the tissue is malignant or benign and might mean the difference between surgical or non-invasive treatment, Hall contends. "Our goal is that it will significantly reduce the number of surgical biopsies performed."
Palpation imaging measures how much tissue changes, compared to surrounding tissue, when it's acted upon by external forces. The stiffness is determined through a computer mouse-looking object, called a transducer, connected to the ultrasound imaging system. When pressed against the skin, the transducer emits signals into the tissue. The signals then bounce off the tissue back to the transducer, which delivers them to a computer. The computer converts the data into a corresponding image, giving physicians a virtual picture of the tissue's stiffness and texture.
Because the images are projected in real time, researchers can control the image by simply moving the transducer or adjusting the amount of pressure applied.
To date, Hall has tested palpation imaging on breast tissue, having performed more than 175 scans on 40 women at KUMC. He said palpation imaging could have an important advantage over mammography because its images are not jeopardized by particularly dense or fibrous breast tissue, as mammography can be. And unlike mammography, palpation imaging performs equally well in young women and older women.
"Abnormal lumps are the most common way that breast lesions are first detected," he notes.
This new technology has also proven to be something that can be applied to tissue other than breasts. In November, Hall and his colleagues introduced palpation imaging to researchers at the Mayo Clinic in Rochester, Minn., who will test its efficacy on thyroid abnormalities.
Palpation imaging is still in preliminary testing stages; Hall first began a clinical trial in December 2001. However, testing continues at KUMC and will be soon be extended to other institutions in the United States and Europe through funding from the National Institutes of Health.
SOURCE:
Kansas University Medical Center (http://www.kumc.edu)
