An emerging CT technology can make the detection and treatment of gallstones easier according to a new paper on the accuracy of dual energy CT (DECT) for detection of gallstones, said Shambo Guha Roy, MBBS, radiology resident at Mercy Catholic Medical Center, Darby, PA.
Guha Roy
“While working on a night shift as a resident it is not uncommon to encounter a patient with upper abdominal pain who will get a CT first followed by upper abdominal ultrasound and overwhelmingly the ultrasound would not add more to the CT,” Dr. Roy said.
Often a patient may be experiencing gallstones that are not yet calcified and may not be detected on a normal CT. Getting the additional ultrasound can be time consuming, add costs, and may not impact patient’s care.
DECT is an emerging imaging technique that is growing in use. The advanced reconstruction algorithm of DECT in the form of virtual non contrast (VNC) and virtual monochromatic (VMC) images improve the ability to detect non-calcified gallstones, which have been harder to detect using CT alone, Dr. Roy said.
While some studies have shown the effectiveness of DECT in detecting gallstones, Dr. Roy said there had not yet been a study that included a control group to test for real-world sensitivity and specificity.
DECT Demonstrates Higher Sensitivity
The study looked at all patients between January 2018 through December 2020 who underwent both DECT of the abdomen and right upper quadrant ultrasound within six months of each other. The presence or absence of gallstones on ultrasound was used as standard. The CTs were reviewed by four attending radiologists, who were blinded to the ultrasound results. The CT results were taken as either positive or negative for gallstones when at least three readers were in agreement.
Of 209 DECT that were reviewed, 106 had gallstones and 103 did not. In 197 of 209 DECTs studied there was 3:1 agreement between the readers. The DECT was reported as positive in 95 out of 106 patients with ultrasound-proven gallstones. Furthermore, 98 out of 103 patients without gallstone on ultrasound were reported as negative on DECT.
The study found that DECT had a sensitivity of 92% for gallstone detection, which is higher than the previously reported sensitivities in the 70’s using standard CT.
Dr. Roy said detecting those stones earlier, saving patients additional tests and making use of emerging technology can help both radiologists and patients.
“We can avoid the unnecessary ultrasound in the emergency department by instead using DECT if gallstones are suspected,” he said. “It will reduce patient wait time and health care costs if more radiologists are trained on how to pick up gallstones on dual energy CT.”
Access the presentation, “Gallstones Detection On Dual Energy Computerized Tomography (DECT)- Is It Ready For Real-world Use? A Retrospective Observational Study,” (SSGI12-3) on demand at Meeting.RSNA.org.
