Crohn’s disease often leads to bowel wall changes that are difficult to characterise without cross-sectional imaging. While CT involves radiation and MRI can be costly or impractical, transabdominal ultrasound offers a bedside option that can be repeated and integrated into routine care. A recent article published in Insights into Imaging evaluated whether adding elastography to standard ultrasound helps identify bowel narrowing more reliably in adults with active disease. Working from a structured protocol and using endoscopic scoring as reference, the researchers examined whether measures of tissue stiffness strengthen assessment compared with conventional greyscale features alone.
Structured Ultrasound with Elastography
The analysis included adults diagnosed with Crohn’s disease at a single hospital between May 2020 and October 2024. All participants had complete clinical information, ultrasound and endoscopy. Patients with serious comorbidities or contraindications to either test were excluded to ensure image quality and safety. Ultrasound examinations followed a standard sequence that began with greyscale imaging to locate affected bowel, then progressed to elastography to quantify stiffness within the thickest, reliably measurable segment. A trained radiologist used a consistent acquisition approach, monitored peristalsis to limit motion and repeated measurements to achieve stable results. Quality control steps, including equipment presets and acceptance thresholds, were applied to improve repeatability and reduce artefacts from gas, depth or tissue interfaces.
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Endoscopy scored disease severity with a simplified Crohn’s index that served as the reference for narrowing. The ultrasound reading also included a stenosis assessment score derived from greyscale features. Elastography added two quantitative stiffness metrics that reflect how rapidly shear waves travel through tissue and how resistant the bowel wall is to deformation. The goal was to understand whether stiffness adds independent diagnostic value beyond morphology and, if so, whether a combined ultrasound approach improves overall accuracy.
Stiffness Measures Add Independent Value
Baseline clinical features such as age and common inflammatory markers did not clearly separate patients with and without narrowing. In contrast, ultrasound measures showed meaningful differences. Stenosis scores derived from greyscale imaging were higher when narrowing was present, yet stiffness stood out as a stronger discriminator. Both elastography metrics were linked to narrowing on initial tests and remained significant after accounting for other factors. In practical terms, stiffer bowel segments were more likely to represent narrowing than those with similar appearances but lower stiffness.
Performance analysis compared each measure on its own and then evaluated a combined approach. Greyscale scores provided moderate discrimination, whereas stiffness metrics performed better when used separately. Bringing the measures together further improved classification, indicating that morphology and stiffness contribute complementary information. The pattern supports the premise that elastography can help confirm suspected narrowing when greyscale features are equivocal and can boost confidence when both appearance and stiffness point in the same direction.
Workflow Considerations and Practical Limits
The protocol highlighted situations that challenge ultrasound assessment and can reduce sensitivity. Deep pelvic locations, overlying gas and incomplete suppression of bowel motion may degrade elastography quality. Narrowing that is predominantly mucosal can be missed if the sampling focuses on deeper wall layers. Body habitus, lesion depth and operator factors also influence acquisition and measurement stability. These constraints underline the need for careful patient positioning, attention to peristalsis and adherence to standard presets to keep results consistent across examinations.
The comparison with endoscopy and the structured ultrasound score indicates where elastography fits in practice. Ultrasound remains appealing because it is non-invasive, radiation-free and immediately available at the point of care. Elastography adds quantitative stiffness data that greyscale imaging and endoscopy do not provide, creating a more rounded picture of the affected segment. In workflows where CT and MRI are limited by availability or patient factors, a multimodal ultrasound approach can support timely decision-making and may reduce the need for additional tests when findings align. When results diverge or quality is suboptimal, endoscopy and cross-sectional imaging still play a central corroborating role.
A standardised ultrasound pathway that integrates elastography improves the detection of bowel narrowing in active Crohn’s disease compared with greyscale features alone. Quantitative stiffness emerges as an independent indicator of narrowing, and a combined model offers the strongest classification. The protocol’s emphasis on quality control, repeated measurements and expert oversight supports reproducibility, though anatomical and technical constraints remain. The findings support adopting multimodal ultrasound with elastography as a practical addition to routine assessment, while recognising that challenging anatomy, motion and gas require careful technique and appropriate follow-up with established reference tests.
Source: Insights into Imaging
Image Credit: iStock
