Quantitative assessment of ultrasound microvessel imaging in Crohn's disease: correlation with pathological inflammation.

objectiveUltrasound microvessel imaging (UMI) may offer noninvasive, highly sensitive microvessel imaging for assessing Crohn's disease (CD). However, a quantification metric that demonstrates a strong correlation with pathological inflammation is preferred. The objective was to determine if UMI can enhance IBD imaging interrogations.

methodsUMI was performed on bowel wall segments from patients with CD requiring surgery (n = 55 patients). The vessel-length ratio (VLR) measured by UMI was compared with that obtained using color flow imaging (CFI) and with a histopathologic standard evaluated on all bowel layers. Correlations between VLR and pathological inflammation and receiver operating characteristic (ROC) curves between different groups were analyzed to demonstrate the advantages of VLR with UMI.

resultsThe correlation between VLR from UMI and pathological inflammation (R = 0.80) outperformed that of VLR from CFI (R = 0.59). UMI showed a significant difference (p < 0.01) between mild and non-mild inflammation cases, while CFI could not (p = 0.014). In the ROC analysis, VLR with UMI demonstrated an area under the curve (AUC) of 0.93, compared to the AUC of 0.80 for VLR with CFI, indicating better identification of pathological inflammation between mild and non-mild cases. For a sub-cohort of patients with stricture without penetrating complications (n = 19), VLR using UMI also showed better correlation (R = 0.93) with pathological inflammation scores and a higher AUC (0.96) than those of VLR using CFI (R = 0.66 and 0.88, respectively).

conclusionsUMI enhances vessel detection sensitivity compared to CFI and more accurately reflects transmural inflammation in small bowel Crohn's disease. VLR using UMI strongly correlates with pathological inflammation, distinguishing between mild and non-mild cases, notably including patients with stricture without penetrating complications. KEY POINTS: Question Bowel wall thickness and Limberg score from ultrasound are insufficient quantitative metrics for reliable diagnosis of inflammation severity for Crohn's disease. Findings Ultrasound microvessel imaging (UMI) with vessel-length ratio (VLR) is strongly correlated with pathological inflammation and had improved distinction between mild and non-mild inflammation cases. Clinical relevance UMI with VLR has the potential to enhance clinicians' ability to assess disease activity and evaluate therapeutic responses, thereby improving Crohn's disease patient outcomes.