Photo: Michael Dolinger
Unlike in the rest of the country, where intestinal ultrasound rarely is used in the clinic, in New York City, gastroenterologists at Mount Sinai Hospital have made IUS findings the “the fifth vital sign” for inflammatory bowel disease patient care, particularly to monitor disease. Now, new research from the institution and other centers is showing that the tool can identify patients with endoscopic recurrence and possibly predict disease outcomes and treatment response.
“This is a noninvasive tool that’s more accurate than the standard biomarkers or clinical symptoms, and we use it regularly at the point of care without needing patients to fast, without any preparation, and in five minutes we can see if there’s Crohn’s disease recurrence,” said Michael Dolinger, MD, MBA, an advanced pediatric IBD fellow at the Susan and Leonard Feinstein IBD Clinical Center at Mount Sinai.
Dr. Dolinger, who has made IUS the focus of his research, presented his latest study at the 2022 Congress of the European Crohn’s and Colitis Organisation (ECCO). He and his co-investigators analyzed IUS results performed at the point of care in 18 patients with Crohn’s disease who had undergone ileocolonic resection a median 45 months previously (range, 29-99 months). All the patients also underwent colonoscopy within 30 days of IUS, and 44% were found to have endoscopic recurrence.
Dr. Dolinger’s team found that bowel wall thickness and hyperemia in the neoterminal ileum and bowel wall thickness at the ileocolonic anastomosis were significantly associated with endoscopic recurrence upon colonoscopy. Specifically, the average bowel wall thickness in patients with endoscopic recurrence was 4 mm (range, 3.2-4.8 mm), compared with 2 mm (range, 1.5-2.6 mm) among those without recurrence (P=0.04). Six patients with endoscopic recurrence had bowel wall hyperemia in the neoterminal ileum, compared with none of those in endoscopic remission at the time of colonoscopy (P=0.007).
Statistical analyses showed that a bowel wall thickness of 3.2 mm had a positive predictive value of 100% in identifying endoscopic recurrence, a negative predictive value of 97.3%, sensitivity of 75% and specificity of 100%.
Moreover, although neoterminal ileum bowel wall thickness correlated with the Rutgeerts score (P=0.04), an endoscopic measure of postoperative disease recurrence, it did not correlate with the Harvey-Bradshaw Index, a clinical measure of disease activity. That finding suggests that clinical symptoms alone are not reliable predictors of Crohn’s disease recurrence, Dr. Dolinger noted.
“What we were able to show is that IUS is accurate, compared to colonoscopy, in identifying those with endoscopic recurrence,” he told Gastroenterology & Endoscopy News.
Unlike colonoscopy, which is the gold standard for evaluating disease activity but invasive and costly, IUS is low cost and can be performed in the clinic, “early and often, and gives physicians a way to monitor response to treatment or surgery and intervene when necessary to control inflammation,” Dr. Dolinger said.
“Here at Mount Sinai, there was initial skepticism among many about the use of IUS for disease monitoring, but that has been replaced by so much enthusiasm, and now people say it’s like a fifth vital sign for IBD, and many don’t do a clinic visit without it,” he said.
Ashwin Ananthakrishnan, MD, MPH, an associate professor of medicine at Massachusetts General Hospital, in Boston, who was not involved in the study, said Dr. Dolinger’s research provides convincing evidence—albeit from a small number of patients—that IUS has value in assessing postoperative recurrence. “For post-op management, active monitoring for recurrence is an important component, and this is an added tool to achieve that,” he said.
Two recent studies from researchers in Europe, where IUS is used more commonly in IBD care, point to additional potential clinical value of IUS in IBD care.
In a Danish study presented at ECCO, investigators followed a cohort of 60 IBD patients who underwent IUS at the time of diagnosis (DOP 10). Preliminary results showed that those who required a biologic, bowel resection or IBD-related hospitalization during the following six months had higher scores on the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) at the time of diagnosis than those who did not (66.2 vs. 34.7; P<0.001). Moreover, all patients with an IBUS-SAS score of at least 80 were hospitalized during the six-month follow-up.
“IUS activity at diagnosis of IBD seems to have the capability to predict short-term disease outcome,” the authors wrote in their abstract.
In another study presented at ECCO, Dutch researchers looked at the correlation between early changes in IUS values and response to treatment (DOP 11). They included data from 51 consecutive patients with ulcerative colitis who underwent baseline IUS and endoscopy at the time of treatment initiation with an anti-inflammatory regimen, including 31 who also underwent a second endoscopy eight to 26 weeks after treatment outset. The results showed that a bowel wall thickness of 3.52 mm six weeks after treatment initiation predicted mucosal healing, with 91% sensitivity and 91% specificity, while a bowel wall thickness of 2.98 mm was 87% sensitive and 100% specific in identifying endoscopic response.
“In a point-of-care setting, early treatment evaluation with IUS could guide treatment decisions in [ulcerative colitis] in order to optimize treatment response,” they wrote, referring to IUS as “a non-invasive alternative to endoscopy.”
Using IUS to predict disease progression and treatment response “is an emerging way to use IUS, and the single-center European studies indicate that it may be an excellent tool—or even the best tool for these purposes, as I believe,” said Dr. Dolinger, who was not involved with the European research.
“The data from these small studies should lead to larger multicenter prospective studies to test these hypotheses, which would help further incorporate IUS into the treatment monitoring algorithm,” he said.
While gastroenterologists at Mount Sinai have incorporated IUS into their IBD monitoring protocol, there are several reasons the modality is not used commonly across the country, he noted. First, gastroenterologists in the United States are not typically trained in the use of IUS. That is something Dr. Dolinger hopes to change, with Mount Sinai offering the first ultrasound training course for gastroenterologists in the country in September, organized by the International Bowel Ultrasound Group.
“Once there are more centers with expertise, I think we’ll really start to see exponential growth in use of ultrasound instead of using blood and stool-based biomarkers,” he said.
Dr. Ananthakrishnan, the expert not involved in these studies, said IUS “is an accessible, noninvasive and inexpensive modality to monitor IBD activity, but there are barriers to its use in the United States.” In addition to a lack of gastroenterologist training in ultrasound, he said there are “logistical barriers, such as the [lack] of ultrasound machines in gastroenterology clinics, and financial barriers, like insurance coverage.”
Dr. Ananthakrishnan stressed that it will be important for the health system in the United States “to institute changes that could make ultrasound more accessible within GI practices.”