Ultrasound Patch: Bladder Monitoring & Early Cancer Diagnosis

MIT researchers have developed a wearable ultrasound monitor in the form of a patch, which can image internal organs without the need for an ultrasound operator or the application of gel. The researchers demonstrated in a recent study that the patch can effectively image the bladder and assess its fullness. They believe this innovation could assist patients with bladder or kidney disorders in monitoring the proper functioning of these organs.

This method could also be modified to monitor other organs in the body by adjusting the placement of the ultrasound array and adjusting the signal frequency. These devices might facilitate earlier detection of cancers that develop deep within the body, like ovarian cancer.

“This technology is versatile and can be used not only on the bladder but any deep tissue of the body. It’s a novel platform that can do identification and characterization of many of the diseases that we carry in our body,” says Canan Dagdeviren, an associate professor in MIT’s Media Lab and the senior author of the study.

Lin Zhang, a research scientist at MIT; Colin Marcus, a graduate student in electrical engineering and computer science at MIT; and Dabin Lin, a professor at Xi’an Technological University, have authored a paper detailing their work, which has been published in Nature Electronics. The lab of Dagdeviren, known for its expertise in creating flexible, wearable electronic devices, has recently designed an ultrasound monitor that can be integrated into a bra for breast cancer screening.

In their latest research, the team employed a similar method to produce a wearable patch that can stick to the skin and capture ultrasound images of internal organs. For their initial demonstration, the researchers opted to concentrate on the bladder, partly influenced by Dagdeviren’s brother, who was diagnosed with kidney cancer a few years ago. Following the surgical removal of one of his kidneys, he experienced difficulties in fully emptying his bladder. This prompted Dagdeviren to consider whether an ultrasound monitor that indicates the bladder’s fullness could benefit patients like her brother, or individuals with other bladder or kidney-related issues.

“Millions of people are suffering from bladder dysfunction and related diseases, and not surprisingly, bladder volume monitoring is an effective way to assess your kidney health and wellness,” she says.

Bladder volume is currently measured using a traditional ultrasound probe that requires a visit to a medical facility. Dagdeviren and her team aimed to create a wearable alternative for at-home use. They developed a flexible patch made of silicone rubber with five ultrasound arrays made from a new piezoelectric material.

The arrays form a cross shape to image the entire bladder, which is about 12 by 8 centimeters when full. The patch’s naturally sticky polymer adheres gently to the skin, allowing easy attachment and removal. Underwear or leggings can be used to secure the patch in place once applied to the skin.

Bladder Volume

In a study conducted in collaboration with the Center for Ultrasound Research and Translation and the Department of Radiology at Massachusetts General Hospital, researchers demonstrated that the new patch could produce images comparable to those generated by a traditional ultrasound probe. These images were effective in tracking changes in bladder volume. The study involved 20 patients with varying body mass indexes. Participants were initially imaged with a full bladder, followed by imaging with a partially empty bladder, and finally with a completely empty bladder. The images captured by the new patch closely matched the quality of those obtained with traditional ultrasound, and the ultrasound arrays performed effectively on all participants regardless of their body mass index. The patch eliminates the need for ultrasound gel and does not require the application of pressure, as is the case with a regular ultrasound probe, due to its large field of view that encompasses the entire bladder. To view the images, the researchers connected their ultrasound arrays to the same type of ultrasound machine used in medical imaging centers. However, the MIT team is currently developing a portable device, approximately the size of a smartphone, that can be used for image viewing.

“In this work, we have further developed a path toward clinical translation of conformable ultrasonic biosensors that yield valuable information about vital physiologic parameters. Our group hopes to build on this and develop a suite of devices that will ultimately bridge the information gap between clinicians and patients,” says Anthony E. Samir, director of the MGH Center for Ultrasound Research and Translation and Associate Chair of Imaging Sciences at MGH Radiology, who is also an author of the study.

The MIT team aims to create ultrasound devices for imaging various organs like the pancreas, liver, and ovaries. To adjust the ultrasound signal frequency based on each organ’s location and depth, the researchers have to develop new piezoelectric materials. In some cases, an implant may be more effective than a wearable patch for organs deep within the body.

“For whatever organ that we need to visualize, we go back to the first step, select the right materials, come up with the right device design and then fabricate everything accordingly,” before testing the device and performing clinical trials, Dagdeviren says.

“This work could develop into a central area of focus in ultrasound research, motivate a new approach to future medical device designs, and lay the groundwork for many more fruitful collaborations between materials scientists, electrical engineers, and biomedical researchers,” says Anantha Chandrakasan, dean of MIT’s School of Engineering, the Vannevar Bush Professor of Electrical Engineering and Computer Science, and an author of the paper.