Diagnostics & Imaging Week

The very act of breathing, or what is termed "respiratory motion,"can throw off radiologists and physicians alike during CT scans, as well as other procedures, particularly in lung biopsies. The reason is that breathing causes the tumor or area of concern to move, making it difficult to locate when conducting CT fluoroscopy-guided biopsies.

Now, the Mayo Clinic (Rochester, Minnesota) has developed the Interactive Breath-hold Control, which it says is the "first medical device of its kind in the world."The device measures the breathing of the patient using a light display, which instructs the patient on when to breathe during the procedure and when to hold a breath by using red and green lights – familiar stop and go signals.

This device would be of most interest to radiologists, who are the "major players,"because it's image-guided intervention, Stephanie Carlson, MD, a Mayo Clinic radiologist and lead investigator of the project, told Diagnostics & Imaging Week. However, other physicians "may benefit from this,"such as radiation oncologists, who also have to address "breath-holding issues"during treatment.

"The other folks that will be interested in this are actually the vendors themselves, because they sell interventional CT packages,"Carlson said. "They've been talking about wanting to include this as an accessory, because [breath-holding is] one of the major issues with CT-guided intervention."

The wireless display device, which is about the size of a handheld video game, according to the clinic, consists of a "simple"belt with expandable bellows that are wrapped around a patient's upper abdomen, individual light displays located next to the patient, the radiologist's image monitor, the CT operator console and a system control unit located next to the patient on the CT table.

"By focusing on the display, patients can easily adjust their breathing and consistently reproduce the same reference breath-hold level,"said Carlson. "This allows the radiologists to conduct a more accurate and safe procedure in less time than if the target area of the lesion were moving."

For example, typically if patient breathing disrupts the imaging process in needle biopsies, it may require more "puncture attempts,"Carlson said.

Mayo conducted randomized clinical trials, in which such things as needle puncture attempts were evaluated. More punctures in an effort to get the biopsy could possibly lead to a greater risk of complications, as well as longer procedure time. The trials were conducted at the Mayo Clinic and in Munich, Germany.

"We showed a decrease in needle puncture attempts, procedure time, radiation exposure to the patient and to the physician, and a decrease in complications,"Carlson said, noting that a "stationary"nodule or one that comes back within the original view of the radiologist following a breath can "decrease all those variables."

And the Interactive Breath-hold Control typically does reduce procedure time, but she said the "key things are increasing the safety and the accuracy."

Another advantage of the breath-hold device is that it allows patients with very small nodules to undergo needle biopsy vs. surgery. Carlson said that traditionally, patients with nodules less than 1.5 millimeters would not have the option of a needle biopsy, but would only be referred for surgical biopsy. Surgical biopsy procedures require as much as a two-to-four-day stay in the hospital, the clinic said. That hospital stay compares to a 30-45 minute CT-guided procedure, it added.

"The system also helps distract anxious patients during the procedure by giving them something to focus on other than the needle,"Carlson said. "By using this device, patients become less focused on the procedure and the possible discomfort associated with it."

The Mayo team also suggested other possible applications for the device, such as tumor ablation procedures, intratumoral injections, PET/CT scanning and possibly even robotic interventional procedures.

Another important aspect of the device is that it is "patient-friendly,"Carlson said, in that it is simple to use and can't harm the patient.

In characterizing the significance of the device development, she said, "The key words right now at NIH and in healthcare are minimally-invasive techniques. It's a device that helps us [achieve] minimally-invasive procedures as opposed to surgery. So, they're really trying to push image-guided [procedures]."

The device, which is patented, will be commercialized through a division at Mayo called Mayo Clinic Medical Devices. Carlson suggested that it will be OEMs who would be interested in the device to sell "either as an accessory to a CT machine"or a separate device, or even as a "package."

"This is actually the second medical device that Mayo has come out with in the last few years,"she said.