1
A
B
C
D
E
F
G
H
Jejunum | Segment
2
A
B
C
D
E
F
G
H
Ileum | Segment
3
Terminal Ileum
4
Right Colon
5
Transverse Colon
6
Descending Colon
7
Sigmoid
8
Rectum
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PICMI

Pediatric Inflammatory Crohn's Magnetic Resonance Enterography [MRE] Index
  • PICMI
About

PICMI (Pediatric Inflammatory Crohn's Magnetic Resonance Enterography [MRE] Index)1-5

Aim: To standardize the scoring of transmural inflammation in children with Crohn’s disease across all segments of the intestine, without the need for contrast enemas or intravenous gadolinium. 

PICMI incorporates five radiological items, scored in every bowel segment: wall thickness, diffusion-weighted imaging (DWI) hyperintensity, wall ulceration, mesenteric edema, and the comb sign. The weighted global score correlates with several constructs of disease activity, including radiologist global assessment and endoscopic inflammation (r = 0.63,p < .001). Inter-observer reliability is high (ICC = 0.84), test-retest reliability is excellent, and the score is responsive to change over time. PICMI ≤10 defines transmural healing, and a decrease of >20 points defines response (AUC 0.96 [95% CI 0.93–0.99]).¹

Therapeutic & Diagnostic Evidence:

  • Treatment evaluation: In a prospective single-center study, adalimumab achieved PICMI-defined transmural response (>20-point drop) more often than immunomodulator maintenance therapy (54% vs 31%, P = .01).³
  • Diagnostic correlation: At diagnosis, PICMI correlates with endoscopic disease activity.⁴
  • Prognostic value: In a multicenter, multireader study, MRE findings carried prognostic value for the subsequent disease course in children with Crohn’s disease.²
  • Clinical adoption: A 2026 review describes the use of PICMI in clinical practice alongside Japan’s MREC classification and score, with illustrative pediatric cases.⁵
Calculator
calculator
1
Jejunum
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
B
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
C
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
D
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
E
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
F
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
G
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
1
Jejunum
Segment
H
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
B
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
C
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
D
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
E
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
F
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
G
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
2
Ileum
Segment
H
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
3
Terminal Ileum
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
4
Right Colon
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
5
Transverse Colon
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
6
Descending Colon
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
7
Sigmoid
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
8
Rectum
Segment
A
Wall thickness
Measure the thickest part within the segment. Round mm to the nearest whole number.
Ulceration
Mucosal indentation smaller than the full thickness of the bowel wall
Wall restricted diffusion
A subjective measure of hyperintensity on highest b value trace image compared to normal bowel
Mesenteric edema
T2 hyperintense signal of the mesentery adjacent to the same bowel loop assessed
Comb sign
Vascular engorgement related to the bowel loop assessed
Total Score:
User guide notees:

The total PICMI score is the sum of the segmental scores for each of the involved segments: jejunum, ileum, terminal ileum (10 cm from the ileo-cecal valve), right colon, transverse colon, descending colon, sigmoid, and rectum (the jejunum and ilium are divided into eight segments, one or more of which can be scored if involved). 

Segmental PICMI (scored based on the worst part) = wall thickness (≥3mm) x 3 + ulceration (0/1) x 6 + wall restricted diffusion (0/1) x 9 + mesenteric edema (0/1) x 6 + comb sign (0/1) x 9

Small bowel scoring: If there is > 20 cm of affected bowel in the jejunum or ileum, each 20 cm length is scored as a separate segment. For example, 18 cm is one segment, 25 cm or 36cm are two segments, and 44 cm is three separate segments (20 + 20 + 4), each receiving its own segmental score as above.

Continuous disease versus skip lesions: If the distance between two segments of affected small bowel is ≤ 20 cm, the unaffected bowel is included in the length measurement and is considered part of continuous disease. If the unaffected bowel between two affected segments is >20 cm, the two affected segments are considered skip lesions, and scored separately as two different segments.

Cutoff values in the total PICMI score to determine severity of transmural inflammation:
≤10     Remission
11-55    Mild inflammation
56-120    Moderate inflammation
>120    Severe inflammation

A score change in the PICMI of >20 points define response (i.e. minimally important difference of the PICMI)

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