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A team of physicians and researchers from the Washington University School of Medicine in St. Louis has recently developed a ‘hopeful technique’ that combines ultrasound and photoacoustic technology to evaluate and diagnose malignant ovarian tumors at an early stage.
Ovarian malignancies are often diagnosed at a late stage because there are no specific signs and symptoms and no specific screening test for diagnosing ovarian cancer. Only 15% of ovarian cancers are detected at early stages.
The American Cancer Society estimates that about 22,240 women will receive a new diagnosis of ovarian cancer and about 14,070 women will die from ovarian cancer in the year 2018.
The researchers recently conducted a pilot study using co-registered photoacoustic tomography with ultrasound to evaluate ovarian masses in 16 patients at the School of Medicine and Barnes-Jewish Hospital. The results were recently published in the journal Radiology.
The team involving Quing Zhu, professor of biomedical engineering in the School of Engineering & Applied Science created a sheath using optical fibers that encases the standard transvaginal ultrasound probe. The optical fibers are connected with a laser source.
As the sheath is introduced in the vagina, the laser light penetrates the vaginal wall to get absorbed by the tumor to generate sound waves to reveal information about tumor vasculature and sO2 inside the ultrasound visible ovaries.
A normal ovary is not highly vascular and contains a lot of collagen tissue, but a malignant tissue is highly vascular because of neoangiogenesis. Using this multispectral photoacoustic imaging, the team looked at 26 ovarian masses from 16 participants that included nine invasive epithelial ovarian cancers (six serous carcinomas and three endometroid adenocarcinomas), three other tumors (two borderline serous tumors and one sex cord-stromal tumor), and 14 benign and normal (hereafter referred to as benign/normal) ovaries.
The researchers used two biomarkers to study the ovaries: relative total hemoglobin concentration (rHbT), which is directly dependent on the tumor angiogenesis, and mean oxygen saturation (sO2). The rHbT was almost two times higher for invasive epithelial cancerous ovaries as compared to normal ovaries P = .01) and the mean sO2 of invasive epithelial cancers, and the borderline and stromal tumors, was 8.2% lower than that of benign/normal ovaries (P = .003).
“Physicians are very excited about this because it might bring significant change into current clinical practice,” Zhu said. “It is very valuable to detect and diagnose ovarian cancers at early stages. It is also important to provide information and assurance to patients that there is no worry about their ovaries, instead of removing a patient’s ovaries. This technology can also be valuable to monitor high-risk patients who have increased risk of ovarian and breast cancers due to their genetic mutations. The current standard of care for these women is performing risk reduction surgeries to remove their ovaries at some point, which affects their quality of life and causes other health problems.”
Encouraged by the results of the pilot study, the team is gearing up to validate the findings in larger subjects and has applied for funding.
Here is a short video showing Dr. Zhu explaining the technology
