Johns Hopkins researchers have, for what is believed to be the first time, used a magnetic resonance imaging (MRI) technique called diffusion-weighted MRI (DWI), a technique that images the movement, or diffusion, of water molecules in tissues, to successfully determine the effectiveness of high-intensity focused ultrasound for treating uterine fibroids.
Uterine fibroids are noncancerous tumors that line the uterine wall and can cause intense pain and bleeding. The study appears in the July edition of Radiology.
Ultrasound treatment works by directing focused ultrasound energy that heats the targeted tissue to induce cell damage or death without damaging the surrounding tissue. Because it's noninvasive, the treatment provides a desirable alternative to conventional surgery and was undergoing clinical trials nationally and was recently given FDA approval.
When fibroids or other tissues are damaged or destroyed by ultrasound treatment, water molecules are trapped within the tissue because the cellular pumps that control the movement of water into or out of cells no longer function properly. By measuring the movement of this water using DWI, the researchers hoped to better gauge the impact of treatment on the fibroids by using a quantitative biophysical parameter called the apparent diffusion coefficient (ADC).
Currently, treatment success is determined using regular MRI with a contrast agent (a dye injected into the patient to enhance the resulting image). However, the image produced during this procedure does not precisely show functional information on the degree of fibroid destruction. Therefore, physicians also rely on questionnaires administered to patients after their fibroid treatment, which often are very subjective and unreliable.