Does the use of computed tomography scenogram alone enable diagnosis in cases of bowel obstruction?

Table 1 Etiologies of cases with mechanical obstruction in this study

Causes of mechanical obstruction	Case count
Postoperative adhesion	21
Hernia	10
Epigastric	2
Femoral	2
Incisional	1
Indirect inguinal	2
Umbilical	2
Obturator	1
Colon cancer	6
Ascending	1
Descending	2
Transverse	1
Sigmoid	2
Volvulus	3
Sigmoid	3
Ileitis due to Crohn's disease	1
Closed loop obstruction	1

Table 2 Observer's concordance with the final diagnosis of obstruction in the scenogram, n (%)

	Mechanical obstruction by final diagnosis			Specificity, %	Sensitivity, %	PPV, %	NPV, %	Accuracy, %
	Yes	None	Total
I Observer
Yes	32 (76.2)	4 (100)	36 (78.3)	76.19	0	88.88	0	69.56
None	10 (23.8)	0 (0)	10 (21.7)
II Observer
Yes	35 (83.3)	4 (100)	39 (84.8)	83.31	0	89.74	0	76.08
None	7 (16.7)	0 (0)	7 (15.2)
III Observer
Yes	35 (83.3)	2 (50)	37 (80.4)	83.33	50	94.59	22.23	80.43
None	7 (16.7)	2 (50)	9 (19.6)
Total	42 (91.3)	4 (8.7)	46 (100)

Table 3 Concordance of the segmentation diagnoses of the observers with the final diagnosis in the scenogram, n (%)

	Mechanical obstruction segment by final diagnosis			Specificity, %	Sensitivity, %	PPV, %	NPV, %	Accuracy, %
	Large	Small	Total
I Observer
Large	12 (85.7)	19 (59.4)	31 (67.4)	85.70	40.62	38.67	86.69	54.33
Small	2 (14.3)	13 (40.6)	15 (32.6)
II Observer
Large	8 (57.1)	10 (31.3)	18 (39.1)	57.14	68.75	44.40	78.60	65.22
Small	6 (42.9)	22 (68.8)	28 (60.9)
III Observer
Large	12 (85.7)	7 (21.9)	19 (41.3)	85.71	78.12	63.12	92.60	80.43
Small	2 (14.3)	25 (78.1)	27 (58.7)
Total	14 (30.4)	32 (69.6)	46 (100)

Table 4 Inter-observation agreement of obstruction and segmentation diagnoses in the scenogram in repeat measurements by the observers, n (%)

	Observer	Positive predict rate (large)	Negative predict rate (small)	P valuea
Obstruction	I	36 (100)	8 (80)	0.500
	II	35 (89.7)	6 (85.7)	0.375
	III	36 (97.3)	8 (88.9)	0.999
Segmentation	I	20 (64.5)	13 (86.7)	0.022
	II	16 (88.9)	23 (82.1)	0.453
	III	18 (94.7)	26 (96.3)	0.999

^aMcNamer test.

Table 5 Concordance of observers' second scenogram obstruction diagnoses with the final diagnosis, n (%)

	Mechanical obstruction by final diagnosis			Specificity, %	Sensitivity, %	PPV, %	NPV, %	Accuracy, %
	Yes	None	Total
I Observer
Yes	34 (81)	4 (100)	38 (82.6)	81	0	88.47	0	73.91
None	8 (19)	0 (0)	8 (17.4)
II Observer
Yes	32 (76.2)	4 (100)	36 (78.3)	76.19	0	88.88	0	69.56
None	10 (23.8)	0 (0)	10 (21.7)
III Observer
Yes	35 (83.3)	2 (50)	37 (80.4)	83.33	50	94.59	22.23	80.43
None	7 (16.7)	2 (50)	9 (19.6)
Total	42 (91.3)	4 (8.7)	46 (100)

Table 6 Concordance of the segmentation diagnoses of the observers with the final diagnosis in the second scenogram, n (%)

	Mechanical obstruction segment by final diagnosis			Specificity, %	Sensitivity, %	PPV, %	NPV, %	Accuracy, %
	Large	Small	Total
I Observer
Large	12 (85.7)	10 (31.3)	22 (47.8)	85.71	68.75	54.50	91.68	73.91
Small	2 (14.3)	22 (68.8)	24 (52.2)
II Observer
Large	9 (64.3)	12 (37.5)	21 (45.7)	64.29	62.50	42.82	80.03	63.04
Small	5 (35.7)	20 (62.5)	25 (54.3)
III Observer
Large	13 (92.9)	6 (18.8)	19 (41.3)	92.86	81.25	68.39	96.30	84.78
Small	1 (7.1)	26 (81.3)	27 (58.7)
Total	14 (30.4)	32 (69.6)	46 (100)

Table 7 Inter-rater (intra-observation) agreement of the evaluators' diagnoses of obstruction and segmentation on the scenogram, n (%)

	Observer	Positive predict rate	Negative predict rate	κ (95%CI)	P value
Obstruction	I vs II	34 (94.4)	5 (50)	0.498 (0.336-0.660)	0.001
	I vs III	33 (91.7)	6 (60)	0.536 (0.382-0.690)	< 0.001
	II vs III	35 (95.5)	5 (55.6)	0.548 (0.386-0.710)	< 0.001
Segmentation	I vs II	14 (45.2)	11 (73.3)	0.151 (0.03-0.272)	0.228
	I vs III	18 (58.1)	14 (93.3)	0.426 (0.314-0.538)	0.001
	II vs III	13 (68.4)	22 (81.5)	0.503 (0.373-0.633)	0.001

CI: Confidence interval; κ: Cohen Kappa.