Role of intestinal ultrasound in ulcerative colitis: A systematic review

Table 2 Studies evaluating scoring systems to assess disease activity in ulcerative colitis based on intestinal ultrasound

Ref.	Study type	Follow-up duration	IUS activity	Comparator	Number of patients	Results
Allocca et al[16]	Prospective	6 mo	BWT, CDS, BWS, lymph nodes	Colonoscopy	53 UC patients	BWT and CDS were independent predictors of colonoscopic activity; Humanitus ultrasound criteria: (1) BWT > 3 mm with CDS; and (2) BWT > 4.43 and absence of CDS. MUC > 6.2: Sensitivity 71%, specificity: 100%, AUC: 0.891. Addition of FCP increased sensitivity to 100%
Allocca et al[17]	Prospective	6 mo	BWT, CDS	Colonoscopy	43 UC patients	MUC score > 6.2 discriminated active UC (sensitivity 85%, specificity 94%, AUC 0.902); external validation study
Allocca et al[18]	Prospective	1.6 years (median)	MUC	-	98 UC patients	Milan ultrasound criteria > 6.2 at baseline was statistically significantly associated with adverse disease outcomes (treatment escalation, steroid use, hospitalization, and colectomy) (HR: 3.87)
Allocca et al[19]	Prospective	1 year	MUC	Colonoscopy	49 UC patients	MUC ≤ 6.2 at wk 12 is independent predictor of MES ≤ 1 at 1 year (OR: 5.8)
Maeda et al[20]	Retrospective	1 year	Milan criteria	Endoscopic Mayo score, fecal calprotectin	58 UC patients	MUC > 6.2 predicted 1 year relapse (HR: 3.22)
Goodsall et al[4]	Prospective cohort	8 wk	Milan criteria, BWT	NHI, colonoscopy (UCEIS score)	29 UC patients	IUS + FC accurately predicted histological activity in 88% of cases (sensitivity 88%, specificity 80%, positive predictive valve 95%, and negative predictive valve 57%)
Piazza et al[21]	Prospective, multi centre	11.5-31.9 mo	MUC, BWT	MES, FCP, CRP	141 UC patients	MUC > 7.7 was better in predicting colectomy (AUC: 0.83) risk than MES
Rispo et al[22]	Prospective	Cross-sectional	MUC	Colonoscopy (MES)	86 UC patients	Conventional and hand-held ultrasound had excellent agreement for MUC (kappa = 0.86). No difference in diagnostic accuracy (0.87 IUS vs 0.84 hand-held IUS)
Bots et al[23]	Prospective	3 wk	BWT, vascularity, haustrations, fat wrapping	Colonoscopy	60 UCpatients	UC-IUS score was developed which has strong correlation with endoscopic disease activity (ρ = 0.83 for Mayo score, ρ = 0.76 for UCEIS score)
Komatsu et al[24]	Retrospective validation	-	BWT, submucosal index	Colonoscopy	44 UC patients	High PPV (95%) and NPV (80%) to predict endoscopic improvement

CD: Crohn’s disease; IUS: Intestinal ultrasound; FC: Faecal calprotectin; UC: Ulcerative colitis; MUC: Milan ultrasound criteria; CI: Confidence interval; HUS: Humanitas ultrasound criteria; CWF: Colon wall flow; CWT: Colon wall thickness; SUS-CD: Simple ultrasound score-Crohn’s disease; IBUS-SAS: International bowel ultrasound-segmental activity score; BWT: Bowel wall thickness; CDAI: Crohn’s disease activity index; DBE: Double balloon enteroscopy; US-CD: US scoring system for Crohn’s disease; UC-IUS: Ulcerative colitis intestinal ultrasound; ρ: Spearman’s rho; UCEIS: Ulcerative colitis endoscopic index of severity; PPV: Positive predictive value; NPV: Negative predictive value.