Seno Medical’s ImagioTM breast imaging system has the potential to provide physicians with vital information needed to better determine whether a suspicious mass is cancerous with the goal of reducing the rate of negative biopsies. Each year in the U.S., 1.6 million women undergo core needle or surgical breast biopsies after a suspicious mass is found through breast imaging or self-exams.1 However, more than 80 percent of these biopsies reveal benign pathology.2
Seno’s opto-acoustic technology fused with ultrasound (OA/US) may reduce negative biopsies by combining laser optics and acoustics, providing radiologists greater confidence to confirm or rule out malignancies better than they can with ultrasound alone.3 The process starts by using laser light of two specific wavelengths to microscopically expand the affected cells, creating a soundwave that can be ultrasonically detected and registered. Blood within and around masses preferentially absorbs the light over normal tissue and becomes slightly heated. A transient thermoelastic expansion causes a tumor to emit a pressure or acoustic wave. This acoustic wave is then detected by sensors within the hand-held, opto-acoustic (OA) probe as it is positioned over the indicated area of the breast.
Signals from the sensors are analyzed and co-registered into images that present a real-time blood map of the lesion in striking color. OA image contrast is related to both blood volume and oxygenation status. In general, malignant masses are more vascular and deplete oxygen from the blood at a higher rate than do benign masses. The two wavelengths of laser light that are used in the Imagio™ OA system facilitate imaging by showing the relative differences between oxygenated and deoxygenated blood.
Advantages of opto-acoustic imaging over anatomical imaging techniques include:
- OA imaging has the merit of both the high contrast and spectral specificity of optical imaging, and the sensitivity and spatial resolution of ultrasonic imaging. It is more than just a combination of the two methods.
- The goal is to incorporate laser-induced sound generation with ultrasonic sound detection to achieve improved specificity over conventional ultrasound alone.
- Unlike anatomical imaging techniques, such as mammography, laser OA imaging may detect breast cancer at its earliest clinically significant stage (3 mm. versus 10 mm. with mammography) without patient discomfort, need for injected contrast or radionuclide or exposure to potentially harmful ionizing radiation.4 The Seno Feasibility Study provided preliminary evidence that fused OA/US images improved specificity while maintaining the same acceptable sensitivity as conventional diagnostic ultrasound.5
- The Imagio™ breast imaging system uses laser energy that is well below the level determined to be safe for human skin. Other than minimal safety measures to protect from stray laser light, there are no costly facilities improvements to the same degree as with mammography, PEM, MRI or PET/CT.
- OA can display real-time functional information about the metabolism of tumors. OA provides information about tumor metabolism, demonstrates the relatively greater deoxygenation within malignant tissues and demonstrates increased blood within masses and the tissues that surround the masses. Unlike PET/CT, PEM and BSGI, OA does not use ionizing radiation, and unlike an MRI, OA does not use contrast agents,4 making Imagio™ fast and comfortable for patients with no follow-up monitoring due to the procedure itself.
- The pilot and MAESTRO interim analyses concluded that benign masses classified as BI-RADS 3, 4A and 4B could be downgraded 1-2 categories, potentially reducing biopsies and in some cases, even potentially minimizing the need for short interval follow-up imaging examinations. OA/US findings may increase suspicion and add certainty to the need for biopsies in malignant masses.
How OA Increases Diagnostic Specificity
OA imaging is a fusion of real-time spatially co-registered and temporally interleaved OA and B-mode information that shows both functional findings (relative oxygenation and deoxygenation of hemoglobin, especially in regions of angiogenesis) combined with morphological structures (for ready association with familiar gray scale US images) both within and around breast masses, all with the convenience and comfort of a hand-held probe. This addition of functional information greatly expands the ability of the radiologist to diagnose otherwise questionable lesions, thus reducing the risk and increasing the specificity.
1. Patient Pamphlet
2. White, R. et al., “Impact of core-needle breast biopsy on the surgical management of mammographic abnormalities,” Ann. Surg. 233, 769-777 (2001)
3. New Interim Results Support Imagio® Opto-acoustic (OA) Breast Imaging System’s Potential to Reduce Negative Biopsies.
4. Opto-Acoustic Imaging. http://senomedical.com/technology/optoacoustic-imaging/
5. Opto-acoustic Image Fusion Technology for Diagnostic Breast Imaging in a Feasibility Study. SPIE Medical Imaging 2015, February 22, 2015, Orlando, Florida.