Correlation of MRI-determined small bowel Crohn’s disease categories with medical response and surgical pathology

Table 1 Grouping by MRI findings

	Category 1	Category 2	Category 3	Category 4
Mucosal enhancement	Nil	Mild	Mild	Mild or marked
Transmural enhancement	Nil	Nil or mild	Nil or mild	Marked
Wall thickness (mm)	> 3	< 6	> 6	> 3

Patients were grouped on the basis of the SB wall thickness and mucosal or transmural enhancement. The 4 categories could also be described as (1) fibrosis, (2) mild segmental hyper-enhancement and mild wall thickening, (3) mild segmental hyper-enhancement and marked wall thickening, and (4) marked segmental transmural hyper-enhancement.

Table 2 Characteristics of the CD patients prior to the MRI examination

	CD (n = 52)
Gender: male	38.5% (20/52)
Age at diagnosis (yr)	38.9 ± 16.0 (14-79)
A1 ≤ 16	11.5% (6/52)
A2 17-40	55.8% (29/52)
A3 > 40	32.7% (17/52)
Crohn’s disease
L1 Terminal ileum	78.8% (41/52)
L2 Colon	0% (0/52)
L3 Ileocolonic	19.2% (10/52)
L4 Upper GI	7.7% (4/52)
P Perianal	9.6% (5/52)
B1 Non-stricturing
Non-penetrating	75.0% (39/52)
B2 Stricturing	19.2% (10/52)
B3 Penetrating	5.8% (3/52)
Colectomy	11.5% (6/52)
Terminal ileal resection	25.0% (13/52)
Proximal SB resection	1.9% (1/52)

Table 3 MRI findings of patients according to the MRI category

MRI group (n)	Male (%)	Age (yr)	Bowel length involved (cm)	Wall thickness (mm)	Degree of SB wall enhancement	Mucosal enhancement (%)	Transmural enhancement (%)	Mesenterichyperaemia (%)	Fibrofatty proliferation (%)	Regional lymph nodes (%)	Free fluid (%)	Narrowed lumen no hold-up (%)	Prestenotic dilation ± holdup (%)	Fistula (%)
1 (7)	28.6	37.9 ± 9.4	6.3 ± 7.9	< 3 0%	None 100%	0	0	0	14.3	0	14.3	57.1	14.3	0
		(23-54)	(1-25)	3-6 71.4%	Mild 0%
				> 6 28.6%	Marked 0%
2 (9)	22.2	32.8 ± 9.2	13.8 ±12.3	< 3 11.1%	None 0%	100	88.9	33.3	33.3	66.6	33.3	44.4	0	22.2
		(17-78)	(3-30)	3-6 88.9%	Mild 100%
				> 6 0%	Marked 0%
3 (16)	43.8	40.1 ± 16.2	16.2 ± 12.0	< 3 0%	None 0%	93.8	43.8	50.0	62.5	37.5	18.8	18.8	62.5	25.0
		(14-79)	(2-50)	3-6 0%	Mild 100%
				> 6 100%	Marked 0%
4 (20)	45.0	41 ± 19.2	19.2 ± 11.6	< 3 0%	None 0%	100	90.0	75.0	75.0	85.0	35.0	35.0	35.0	20.0
		(14-49)	(2-45)	3-6 10%	Mild 0%
				> 6 90%	Marked 100%

Table 4 MRI category, medical therapy and clinical response (%)

MRI group	Steroids	5ASA	Antibiotics	AZA/6MP	MTX	Anti-TNF α	Response
1 (n = 7)	57.10	57.10	28.50	85.70	0.00	42.90	14.30
2 (n = 9)	55.50	88.90	0.00	22.20	33.30	44.40	100.00
3 (n = 16)	81.30	68.80	6.30	50.00	0.00	12.50	43.80
4 (n = 20)	70.00	70.00	5.00	40.00	0.00	35.00	50.00
Responders (n = 27)	63.00	63.00	11.10	44.40	3.70	25.90	N/A
Non-responders (n = 25)	76.00	80.00	4.00	48.00	8.00	36.00	N/A

5ASA: 5 aminosalicylic acid; AZA/6MP: Azathioprine/6 mercaptopurine; MTX: Methotrexate; N/A: Not applicable.

Table 5 MRI category, response to medical therapy in relation to luminal narrowing with and without hold up

MRI group	No narrowed lumen	Narrowed lumen no hold up	Narrowed lumen with hold up
1	Response 0% (0/2)	Response 25% (1/4)	Response 0% (0/1)
n = 7	No response 100% (2/2)	No response 75% (3/4)	No response 100% (1/1)
2	Response 100% (5/5)	Response 100% (4/4)	Response N/A
n = 9	No response 0% (0/5)	No response 0% (0/4)	No response N/A
3	Response 66.7% (2/3)	Response 66.7% (2/3)	Response 40% (4/10)
n = 16	No response 33.3% (1/3)	No response 33.3% (1/3)	No response 60% (6/10)
4	Response 83.3% (5/6)	Response 57.1% (4/7)	Response 14.3% (1/7)
n = 20	No response 16.7% (1/6)	No response 42.9% (3/7)	No response 85.7% (6/7)
Total	Response 75.0% (12/16)	Response 61.1% (11/18)	Response 27.8% (5/18)
n = 52	No response 25.0% (4/16)	No response 38.9% (7/18)	No response 72.2% (7/18)

Table 6 Correlation of MRI findings with surgical pathology

No.	Sex	Age	MRI assessment		Surgical pathology
			Group	Fistula	Inflammation	Fibrosis	Fistula
1	F	23	1	No	Minimal	Yes	No
2	M	45	1	No	No	Yes	No
3	F	39	2	Yes	Mild	No	Yes
4	M	17	3	No	Mild	Yes	No
5	F	59	3	No	Mild	Yes	No
6	F	31	3	No	Mild	Yes	No
7	M	18	3	No	Moderate	Yes	No
8	M	24	3	Yes	Mild	Yes	Yes
9	F	37	3	No	Mild	Yes	No
10	M	41	3	No	Mild	Yes	No
11	F	62	4	No	Florid	Yes	No
12	M	19	4	No	Florid	Yes	No
13	M	61	4	No	Florid	Yes	No
14	F	21	4	Yes	Florid	No	Yes
15	M	43	4	Yes	Florid	Yes	Yes
16	M	14	4	No	Florid	No	No
17	F	56	4	No	Florid	No	No