IBD ULTRASOUND CALCULATOR CROHN´S DISEASE

Validated intestinal ultrasound activity indices, calculated in real time. No data is saved, sent or transmitted.

Developed by Dr. J. Poza Cordón · Hospital Universitario La Paz, Madrid · @joaquin_poza

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Core measurements

Shared inputs for Simple US Score, BUSS and IBUS-SAS

Enter up to four BWT measurements from the same target or most affected bowel segment. Do not combine measurements from different segments.

M1Wall thickness 1 (mm)

M2Wall thickness 2 (mm)

M3Wall thickness 3 (mm)

M4Wall thickness 4 (mm)

Not calculated

Average wall thickness

Enter at least one measurement

Limberg grade — Colour Doppler

Grade 0 No Doppler signal Grade 1 1–2 Doppler spots/cm² Grade 2 3–5 Doppler spots/cm² Grade 3 >5 Doppler spots/cm² ± vessels outside

How Limberg is used

Simple US Adds the Limberg grade directly: +0, +1, +2 or +3.

BUSS Adds 0 for grade 0 and 1.65 for any grade ≥1.

SUS-CD Converts the Limberg grade into segmental Doppler points; grades 2 and 3 both contribute 2 Doppler points.

Simple US Score

Average BWT + Limberg grade

Waiting for 2 fields

Simple US

Enter at least one measurement and select Limberg

≤3.1 Likely inactive Current range

>3.1–8 Active disease Se 92.5% · Sp 100% Current range

>8 SES-CD >7 likely Se 73% · Sp 72% Current range

Scoring, interpretation & references

The Limberg grade contributes its numerical value directly: grade 0 adds 0, grade 1 adds 1, grade 2 adds 2 and grade 3 adds 3.

Interpretation

Score range	Interpretation	Performance
≤3.1	Likely inactive disease	Not reported
>3.1 to 8	Active disease	Se 92.5%, Sp 100%
>8	SES-CD >7 likely	Se 73%, Sp 72%

References

1 Ripollés T, Poza J, Suárez C, et al. Inflamm Bowel Dis. 2021.

2 Ripollés T, Poza J, Suárez C, et al. Inflamm Bowel Dis. 2024.

BUSS Score

0.75 × average BWT + hyperaemia component

Waiting for 2 fields

BUSS

Enter at least one measurement and select Limberg

≤3.52 Likely inactive Current range

>3.52 Active disease Se 83% · Sp 85% Current range

Reduction ≥1.2 during follow-up → associated with endoscopic response

Scoring, interpretation & references

Limberg grade	Hyperaemia component
Grade 0	0
Grades 1–3	1.65

Note: BUSS does not add the Limberg grade directly. Any Limberg grade ≥1 contributes 1.65.

Interpretation

Score range	Interpretation	Performance
≤3.52	Likely inactive disease	Not reported
>3.52	Active disease	Se 83%, Sp 85%

A reduction ≥1.2 during follow-up is associated with endoscopic response (≥50% reduction in SES-CD); AUC 0.79.

References

1 Allocca M. Aliment Pharmacol Ther. 2022.

2 Allocca M, et al. Clin Gastroenterol Hepatol. 2022.

IBUS-SAS

4 × BWT + 15 × mesenteric fat + 4 × echostructure + 7 × Doppler

Waiting for 4 fields

IBUS-SAS

Select echostructure, mesenteric fat and Doppler

<25 Mucosal healing predictor AUC 0.85 Current range

25–25.2 Indeterminate Current range

>25.2–63 Active disease Se 82% · Sp 100% · AUC 0.89 Current range

>63 High surgery risk Se 100% · Sp 73% · AUC 0.92 Current range

Scoring, interpretation & references

BWTvalue × 4

Mesenteric fatgrade × 15

Echostructuregrade × 4

Dopplergrade × 7

Interpretation

Score range	Interpretation	Performance
<25	Predictor of mucosal healing post-induction	AUC 0.85
25–25.2	Indeterminate zone	Not reported
>25.2 to 63	Active disease	Se 82%, Sp 100%, AUC 0.89
>63	High risk of surgery at diagnosis	Se 100%, Sp 73%, AUC 0.92

References

1 Novak KL, et al. J Crohns Colitis. 2020. Original IBUS-SAS development.

2 Dragoni G, et al. J Crohns Colitis. 2023.

3 Madsen GR, et al. Clin Gastroenterol Hepatol. 2025.

4 Huang Z, et al. Inflamm Bowel Dis. 2023.

SUS-CD

Sum of segmental BWT and Doppler points

Waiting for data

Unentered segments are considered normal and contribute 0 points.

SUS-CD

Enter data for at least one segment

0 Likely inactive Current range

1–2 Active disease Se 95% · Sp 70% Current range

≥3 SES-CD >7 likely Se 88.5% · Sp 69% Current range

Scoring, interpretation & references

BWT scoring

Measured BWT	BWT points
<3 mm	0
3 to <5 mm	1
5 to <8 mm	2
≥8 mm	3

Rectum: bowel wall thickness only

Measured BWT (rectum)	BWT points
<4 mm	0
4 to <5 mm	1
5 to <8 mm	2
≥8 mm	3

Doppler scoring

Doppler finding	SUS-CD Doppler points
0 · No or single vessel	0
1 · 2–5 vessels/cm²	1
2 · >5 vessels/cm²	2

Important: In the original SUS-CD the rectum is scored on wall thickness alone, with its own thresholds, and no Doppler score is applied.

Unentered segments are considered normal and contribute 0 points.

Interpretation

Score range	Interpretation	Performance
0	Likely inactive disease	Not reported
1–2	Active disease	Se 95%, Sp 70%
≥3	SES-CD >7 likely	Se 88.5%, Sp 69%

References

1 Saevik F, et al. J Crohns Colitis. 2021.

Final summary

Calculated indices and partial SUS-CD results are shown

No index has been calculated yet.

Plain-text summary

For use by trained healthcare professionals as a decision-support aid only. It does not replace clinical judgement, endoscopy or any other diagnostic assessment. All values are entered and processed locally in your browser; nothing is stored or transmitted.