Crohn's disease related strictures in cross-sectional imaging: More than meets the eye?

Strictures in Crohn's disease (CD) are a hallmark of long-standing intestinal damage, brought about by inflammatory and non-inflammatory pathways. Understanding the complex pathophysiology related to inflammatory infiltrates, extracellular matrix deposition, as well as muscular hyperplasia is crucial to produce high-quality scoring indices for assessing CD strictures. In addition, cross-sectional imaging modalities are the primary tool for diagnosis and follow-up of strictures, especially with the initiation of anti-fibrotic therapy clinical trials. This in turn requires such modalities to both diagnose strictures with high accuracy, as well as be able to delineate the impact of each histomorphologic component on the individual stricture. We discuss the current knowledge on cross-sectional imaging modalities used for stricturing CD, with an emphasis on histomorphologic correlates, novel imaging parameters which may improve segregation between inflammatory, muscular, and fibrotic stricture components, as well as a future outlook on the role of artificial intelligence in this field of gastroenterology.

Validation of stricture length, duration and obstructive symptoms as predictors for intervention in ileal stricturing Crohn's disease

BACKGROUND

Risk factors for intervention in terminal ileal (TI) stricturing Crohn's disease (CD) are poorly defined. Novel and rigorous definitions for TI strictures recently became available.

OBJECTIVE

We aimed to describe the rates of symptoms or need for endoscopic balloon dilation (EBD) or surgery as well as risk factors of progression in a well-defined stricturing CD cohort.

METHODS

Consecutive adult patients with non-penetrating stricturing TI CD, as defined by centrally-read magnetic resonance enterography CONSTRICT criteria, were separated into a derivation and validation cohort. Clinical and imaging characteristics were collected following prespecified scoring conventions. Primary outcome was a composite endpoint of EBD or surgery ("intervention"). Multivariable analysis was performed.

RESULTS

Eighty-six patients (48.8% female, median age 36 years) met selection criteria, 17.4% had prior EBD, 59.3% previously received biologics and 58.1% of strictures were anastomotic. Median follow-up was 63.4 [95% CI: 57, 68.9] months. In the derivation cohort, at 12 and 48 months, 26% and 45% of patients had intervention, respectively. Multivariable analysis showed obstructive symptoms (Hazard ratio [HR] 1.444; 95% CI 1.126-1.852), stricture duration (HR 0.974; 95% CI, 0.954-0.995) and length (HR 1.039; 95% CI, 1.011-1.069) predicted intervention. The concordance index for split-sample validation was 0.74 and 0.67, respectively. Biologics were not associated with intervention. An online risk calculator was constructed.

CONCLUSION

In patients with TI stricturing CD, 26% and 45% required intervention at 1 and 4 years. Obstructive symptoms, stricture duration and length were independent and validated predictors of the need for intervention. These findings are important for clinical practice and aid in the design of future trials for CD strictures.