New tools help surgeons find liver tumors, not nick blood vessels

July 17, 2017
This graphic (fig. 1a) represents the mismatch between the liver shape based on a CT scan of the liver (in green) and the shape traced by the intraoperative tracking device during surgery (black dots). Credit: Vanderbilt University

The liver is a particularly squishy, slippery organ, prone to shifting both deadly tumors and life-preserving blood vessels by inches between the time they're discovered on a CT scan and when the patient is lying on an operating room table.

Surgeons can swab the exposed lightly on the surface with a special stylus, capturing the shape of the organ during , and a computer can match that image with the CT scan on a screen. This GPS-like ability is far better than guessing where the tumor and vessels are by feeling for them, but even this road map can be off by centimeters.

Vanderbilt University's Michael Miga, Harvie Branscomb Professor of Biomedical Engineering, and his team published the potential solution: surgery-tested software that better marries the CT scan's image with the tracked tool's. It's an advance that stands to help more than a half-million liver cancer patients worldwide each year. Their paper, "Deformation Correction for Image Guided Liver Surgery: An Intraoperative Fidelity Assessment," appears this month in the journal Surgery.

Used in a blinded, randomized 20-patient bystander study over the past two years at Memorial Sloan Kettering Cancer Center in New York, surgeons said the new technology improved the registration in more than 70 percent of cases.

This graphic (fig. 1b) demonstrates how the mismatch is corrected for using the new software approach. Credit: Vanderbilt University

"Deformation happens," said Miga, who developed the Pathfinder stylus system for abdominal surgeries. It sold to Analogic Corporation in 2014 and is in use at top cancer centers.

"The way the liver is configured in the body at the time of diagnostic imaging and the way it's presented for surgery are very different," he said. "If you're trying to get to a tumor the size of a dime and avoid a blood vessel, you need to avoid errors. The problem is, by the time a surgeon can access the organ for surgery, the CT-derived GPS map could be off by centimeters. That's dangerous, especially if resecting close to a major vessel."

The trick to fixing that error without investing in additional expensive equipment is software that makes a computer model out of the original image of the liver and simulates the forces being applied during surgery—such as packed gauze lifting the liver upward. The computer adjusts the CT-derived GPS map to better match the exposed organ shape in the OR.

In the study, surgeons were shown six or seven CT images, depending on time, for each of 20 liver tumor patients in the operating room, for a total of 125 images. The CT map would either be aligned to the original Pathfinder or Miga's new enhanced CT map that corrected for deformations. The surgeon was not told which display was being presented and would assess the alignment by touching the stylus on the patient's liver and looking at the display. The surgeon would then provide a score on a scale of +3 to -3 relative to the previous display presented. The display order was randomized and could go from enhanced to original, original back to enhanced, or held constant. The surgeon was able to detect the variations correctly in 73 percent of the 125 different evaluations.

This new deformation correction technology is available to be integrated into image-guided surgery systems.

Explore further: Minimally invasive surgery for liver cases compares favorably with open operations

More information: Logan W. Clements et al, Deformation correction for image-guided liver surgery: An intraoperative assessment of fidelity, Surgery (2017). DOI: 10.1016/j.surg.2017.04.020

Related Stories

Minimally invasive surgery for liver cases compares favorably with open operations

October 18, 2016
For patients who may benefit from a major liver operation to treat cancer, an open abdominal procedure is often the only option. However, a minimally invasive approach that avoids the large open incision may soon be a viable ...

New model could benefit liver cancer transplant patients

December 21, 2016
A simple blood test may better predict which patients diagnosed with liver cancer will experience disease recurrence, according to new research from Weill Cornell Medicine scientists. The findings may help physicians determine ...

Radical surgery saves life of young mom

January 6, 2012
A team led by Dr. Alan Hemming, transplant surgeon at UC San Diego Health System, has successfully performed the West Coast's first ex-vivo liver resection, a radical procedure to completely remove and reconstruct a diseased ...

All heart patients have some liver disease after Fontan surgery

May 31, 2017
Patients who undergo the Fontan operation as children for a complex congenital heart defect are at risk of developing progressive liver fibrosis, a buildup of fibrous deposits, as a result of the circulation created by the ...

Has breast MRI been performed upside down?

June 22, 2016
Magnetic Resonance Imaging (MRI) has been used as an effective tool for cancer evaluation and has been found to be highly sensitive in detecting breast tumors, but there is no evidence that pre-operative MRI translates into ...

Recommended for you

One weight-loss surgery shows lasting results

September 21, 2017
(HealthDay)—Obesity surgery can have long-lasting effects on weight and the risk of developing type 2 diabetes and high blood pressure, a new study finds.

Hold the phone: An ambulance might lower your chances of surviving some injuries

September 20, 2017
Victims of gunshots and stabbings are significantly less likely to die if they're taken to the trauma center by a private vehicle than ground emergency medical services (EMS), according to results of a new analysis.

Surgeons have major influence on breast cancer treatment

September 13, 2017
A woman's choice of surgeon plays a significant role in whether she's likely to receive an increasingly popular aggressive breast cancer surgery.

Some thyroid cancer patients can safely delay surgery

September 4, 2017
Most people diagnosed with cancer want to start treatment as soon as possible, for fear that delaying care will allow their tumor to grow out of control.

Obese people lack cells with satiety hormones

August 29, 2017
Individuals with severe overweight have an inhibited sense of satiation - they release fewer satiety hormones than people of normal weight. The reason: the responsible cells in the gastrointestinal tract of obese people are ...

Anesthesia and surgery during infancy may impact white matter during childhood

August 24, 2017
General anesthesia and surgery in otherwise healthy infants under the age of 1 year old could be associated with decreases in the amount of white matter in the brain, as well as reductions in the remaining white matter's ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.