The images, taken by Dr. Alberto Martegani and Dr. Luca Aiani of the Valduce Hospital in Como, Italy, more clearly illuminate blood flow in tiny capillary vessels that feed breast tumours, an important first step in improving cancer diagnosis and treatment. In addition, Sensant presented Silicon Ultrasound images from a recent animal study that also used contrast agents to show detailed blood flow in kidney tissue.
Ultrasound contrast agents consist of millions of micro-bubbles, each smaller than the size of a single red blood cell, that are injected intravenously into the bloodstream. Ultrasound contrast agents such as SonoVue are chemically inert and, unlike many x-ray and magnetic resonance contrast agents, are not associated with toxic side-effects.
When subject to ultrasound, the micro-bubbles produce a harmonic "ringing" that makes them visible in the ultrasound image. Because the acoustic properties of the tiny silicon "drums" that compose a Silicon Ultrasound sensor have a much broader frequency response than conventional ultrasound technology, Silicon Ultrasound detects the ringing contrast micro-bubbles with improved resolution and produces superior images of blood flow.
With Silicon Ultrasound and contrast agents, physicians can visualize flow in the microscopic vessels supplying blood to a tumour. The small size of the contrast agent's micro-bubbles - a mean diameter of 2,5 microns, slightly less than red blood cells, enables them to pass through the vast network of the body's arterial branches, and into the capillary vessels where flow is 1000x slower than in the aorta. Once in the vessels, contrast agents will appear on a contrast-enhanced ultrasound image, making them ideal for imaging the micro-vessels, not otherwise visible with ultrasound, that supply blood to tumours.
Silicon Ultrasound with contrast has the potential to reduce cost and improve the patient experience by reducing the high rate of invasive biopsies, procedures described by patients as both physically and emotionally traumatic. Over one million biopsies were performed last year on women in the United States, and nearly 80 percent proved to be negative. By some estimates, there are nearly one million potentially unnecessary biopsies at a cost of approximately $1 billion per year in the United States.
Ultrasound is already widely used as an adjunct to mammography to rule out benign cysts, and ultrasound with contrast may take this a step farther by distinguishing benign from cancerous masses. Research with contrast-enhanced magnetic resonance imaging (MRI), and early research with contrast-enhanced ultrasound, suggest that vessels associated with malignant tumours are typically arranged in a disorderly, tangled fashion with sharp kinks while benign masses are characterized by low flow or regular, organised vessels. With the additional information on blood flow in a tumour's micro-vessels, physicians may be able to rule out many suspicious masses without invasive biopsy.
In the future, Silicon Ultrasound technology used in conjunction with contrast agents as a primary screening modality may also save lives by providing more informative images that may enable earlier and more accurate diagnosis of malignant breast tumours. Promising initial research using MRI with contrast demonstrates high rates of breast cancer detection in the highest risk women. Ultrasound imaging with contrast, at one-tenth the cost, may offer similar advantages for a much larger group of women.
Sensant CEO Igal Ladabaum commented: "The potential improvement in contrast agent imaging with Silicon Ultrasound is good news in the fight against cancer, and the work on breast tumour imaging with contrast is particularly exciting. Although it's at an early stage, the potential positive ramifications for women are undeniable. Contrast-enhanced ultrasound, and the new diagnostic information it provides, may one day save lives by detecting cancer earlier, and it may also provide a faster, less expensive, and less invasive diagnostic process."
Founded in 1998, Sensant Corporation develops silicon-based sensors for medical ultrasound imaging. Based on its Silicon Ultrasound transducer technology, Sensant provides a revolutionary technology platform to medical imaging companies. Silicon Ultrasound is the enabling technology for major innovations such as volumetric, three-dimensional imaging and improved visualization of tumours using ultrasound contrast agents. Such advances will provide physicians with more informative images that will help to deliver better quality care more quickly and economically.