Optical imaging that measures water content and blood volume in the cheek might be an efficient and non-invasive method to assess short- and long-term remission in people with Cushing’s disease, according to a study.
The study, “Optical Imaging Technology: A Useful Tool to Identify Remission in Cushing Disease After Surgery,” was published in Hormone and Metabolic Research.
Optical imaging is a technology that allows the ability to look inside the body in a non-invasive way, similar to X-rays, but uses visible light instead of radiation. Therefore, it is less damaging than X-rays, and can be used for scans that take a long time or that should be repeated periodically.
The technology is especially useful for examining soft tissues such as muscles, nerves, fat, and blood vessels.
Cushing’s disease happens when a tumor in the pituitary gland produces too much of the adrenocorticotropic hormone (ACTH), making the adrenal glands secrete excess cortisol.
The primary treatment is to remove the tumor surgically, but the symptoms reappear in up to 34% of patients. Measuring cortisol levels helps determine if the surgery was successful, but there are no methods that predict if remission will be long-lasting.
Therefore, researchers wanted to explore if measuring blood volume and water content in the cheeks by optical imaging could determine short- and long-term remission in Cushing’s disease patients who had undergone surgery to remove their tumors.
The team used a kind of optical imaging called near-infrared multi-spectral imaging that takes many images of the face at different wavelengths. This allows researchers to quantify different biomolecules, such as hemoglobin (the molecule that carries oxygen), blood, and water, since each molecule absorbs light differently.
During the study (NIH clinical protocol 97-CH-0076), which lasted from August 2012 to March 2017, researchers analyzed 49 patients, including 34 women, diagnosed with Cushing’s disease. The mean age was 18.5 years.
Patients were imaged before and after surgery. Three patients received two consecutive surgeries, because the first one was not successful, and were imaged after both surgeries. To assess long-term response, the investigators analyzed 22 patients at three to six months after surgery, and 13 patients at one year post-surgery.
“We found a decrease in blood volume fraction after vs. before surgical treatment in the tested facial area in 37 of the 40 (92%) patients” that were in remission, the researchers wrote. They also observed a decrease in water content in 35 of the 40 patients (87%).
In contrast, the 12 patients that did not achieve remission showed higher levels of blood volume and water content after the surgery. In the patients that went through two surgeries, the levels only decreased after the second one.
The researchers stated that optical imaging “is a promising tool to assess remission not only immediately post-operatively but also in follow-up, at least up to 12 months. This technique is safe, noninvasive, fast, and inexpensive, making it ideal to monitor a disease or condition over time.”
Although these preliminary results are promising, more studies are needed to understand fully the impact of optical imaging as a tool in the management of Cushing’s disease, and it should be used as a complement to, and not as a replacement for, traditional methods of diagnosis and evaluation, the study noted.