Using only minimally invasive surgery, a device that combines three previously unrelated imaging tools may help diagnose hard to detect early-stage ovarian cancer in high-risk women, thanks to the efforts of researchers from the University of Connecticut and the University of Southern California in the US. The researchers, who propose the new approach may be better than the current standard method of preemptively removing the ovaries, write about how they tested their device in the September issue of Biomedical Optics Express, the Optical Society of America’s (OSA) open-access journal.

The survival rates for ovarian cancer are low because the disease is hard to detect, hence its reputation as the “silent killer”. The authors write that the disease “is predominantly diagnosed in Stages III or IV due to the lack of reliable symptoms, as well as the lack of efficacious screening techniques”.

Now, by combining multiple imaging tools, the researchers think they have come up with a new way of spotting much earlier the changes in ovarian tissue that indicate cancer.

The new device, which they describe as a “prototype endoscopy system for ovarian tissue characterization”, brings together three imaging technologies: photoacoustic imaging (PAI), optical coherence tomography (OCT) and pulse-echo ultrasound (US). The first provides contrast, the second offers high-resolution sub-surface imaging and the third provides deep-tissue imaging.

In their paper, the researchers describe the prototype device as comprising:

” … a ball-lensed OCT sample arm probe, a multimode fiber having the output end polished at 45 degree angle so as to deliver the light perpendicularly for PAI, and a high frequency ultrasound transducer with 35MHz center frequency.”

They go on to detail how they tested the prototype device on both pig and human ovarian tissue. It correctly identified malignant tumors that were later confirmed by tissue staining and examination under a microscope.

They conclude that:

“The optical absorption contrast provided by PAI, the high resolution subsurface morphology provided by OCT, and the deeper tissue structure imaged by US demonstrate the synergy of the combined endoscopy and the superior performance of this hybrid device over each modality alone in ovarian tissue characterization.”

Although these tests were done on tissue that had already been removed, because the device has a diameter of only 5 mm, the researchers suggest it could be inserted through a small laparoscopic incision during minimally invasive surgery to image tissue in live patients.

Written by Catharine Paddock PhD