Intestinal ultrasound in Crohn’s disease: A systematic review of its role in diagnosis, monitoring, and treatment response

Table 7 Role of intestinal ultrasound in predicting response to biologic therapy

Ref.	Study type	Number of patients	Biologic agent	IUS predictors	Follow up	Time points of IUS	Therapeutic outcomes
Moreno et al[96], 2014	Prospective	34 CD	Anti-TNF and/or immunomodulators	Wall thickness, CDS, wall enhancement	1 year	Baseline and 1 year	Good correlation between endoscopic remission and sonographic normalization (κ = 0.73, P < 0.001), highest correlation with wall thickness
Orlando et al[78], 2018	Prospective	30 CD	Anti-TNF	Strain ratio ≥ 2; BWT ≤ 3 mm	52 weeks	Baseline, week 14 and 52	Surgery higher with strain ratio ≥ 2. Lower strain ratio in those with transmural healing
Paredes et al[98], 2019	Prospective	36 CD	Anti-TNF	Transmural healing	48.5 months	Baseline, 12 weeks, 1 year	TH related to steroid free remission, less need for treatment escalation and surgery
Ungar et al[100], 2020	Prospective, observational	44 CD (50 IUS)	Adalimumab	BWT (TI and colon)	1 year	Within 30 days of trough level measurement	Trough level < 3 µg/mL higher BWT in TI and colon. Adalimumab retention higher with TI BWT < 4 mm
Albshesh et al[99], 2020	Retrospective	60 CD	IFX	BWT	16 months	Baseline	Small bowel BWT ≥ 4 mm associated with treatment failure
de Voogd et al[105], 2022	Prospective	40 CD	Anti-TNF	BWT, color doppler signals, CEUS	32 weeks	Baseline, 4-8 weeks (T1), 12-34 weeks (T2)	18% and 28% decrease in BWT predicted endoscopic response at T1 and T2 respectively. Absence of CDS and CEUS washout rate improved prediction
Chen et al[4], 2022	Prospective pilot study	30 CD	Anti-TNF	BWT, CDS, SWE	14 weeks	Week 2, 6 and 14	Changes in BWT, CDS and SWE occurred as early as week 2 in responders Baseline SWE and BWT were higher in non-responders
Kucharzik et al[109], 2023	Post hoc analysis of RCT	77 CD	Ustekinumab	TH, BWT, CDS, mesenteric fat, stratification	48 weeks	4 weeks, 48 weeks	IUS response, TH, BWT, CDS normalization highest in colon and biologic-naive patients. Week 4 IUS predicted week 48 endoscopic response. IUS endoscopy agreement > 90% (TI)
Vaughan et al[107], 2022	Prospective study	79 UC and 24 CD	Maintenance Infliximab	BWT, CDS	Cross sectional (median disease duration 8 years)	Cross sectional data	Lower infliximab trough level was associated with higher CDS in both UC and CD. Transmural healing in CD was associated with higher infliximab trough levels
Han et al[103], 2022	Retrospective	92 CD	IFX, ADA	BWT, ultrasonographic response	14 weeks	Week 0, week 14	Higher trough levels correlated with significant ultrasonographic response
Hoffmann et al[108], 2020	Prospective	23 CD	Ustekinumab	BWT reduction ≥ 1 mm	8 weeks	Week 0, week 8	Reduction in BWT predicted clinical and biochemical response
Calabrese et al[111], 2021	Prospective	40 CD	Anti-TNF	BWT, CDS	12 months	Baseline, interim, 12 months	Tight-control monitoring improved endoscopic remission and reduced disease activity
Guidi et al[113], 2006	Prospective	20 CD	Infliximab	CEUS enhancement, wall thickness	6 weeks	Baseline, after induction	CEUS changes correlated strongly with inflammatory markers and therapy response
Dolinger et al[112], 2021	Prospective pediatric	15 CD	Infliximab	SWE elasticity changes	1 year	Baseline, Week 14	SWE accurately predicted treatment response in pediatric CD patients
Dolinger et al[163], 2024	Prospective pediatric	30 CD	Infliximab	SWE, CEUS	Cross-sectional	Baseline	Differentiated inflammatory activity from fibrosis, enabling tailored therapies
Ainora et al[115], 2024	Prospective	40 CD	Anti-TNF	Combined IUS parameters with biomarkers	6 months	Baseline, interim, endpoint	Multimodal assessment improved precision in therapeutic adjustments
Allocca et al[110], 2023	Prospective	93 CD	Adalimumab, Ustekinumab, Vedolizumab	BUSS ≤ 3.52, IBUS-SAS ≤ 22.8	12 months	Baseline, Week 12	Week 12 BUSS ≤ 3.52 strongly predicted long-term endoscopic remission (OR 9.93, P < 0.001)

CD: Crohn’s disease; CEUS: Contrast-enhanced ultrasound; IUS: Intestinal ultrasound; BUSS: Bowel ultrasound score; IBUS-SAS: International bowel ultrasound segmental activity score; SWE: Shear wave elastography; BWT: Bowel wall thickness: TNF: Tumor necrosis factor; OR: Odds ratio; IFX: Infliximab; ADA: Adalimumab; CDS: Color doppler signal; TH: Transmural healing; RCT: Randomized controlled trial; UC: Ulcerative colitis.