Computed tomography attenuation values of ascites are helpful to predict perforation site

Table 1 Patient characteristics n (%)

	Colorectum(n = 24)	Other sites(n = 27)	P value
Age (yr)	70 (44-91)1	61 (24-84)1	0.0152
Gender (male)	14 (58.3)	15 (55.6)	1.0003
Reason of perforation			0.8803
Malignancy	5 (20.8)	6 (22.2)
Benign	14 (58.3)	16 (59.3)
Chemo and/or radiotherapy	2 (8.3)	3 (11.1)
Idiopathic	3 (12.5)	2 (7.4)
Ascites accumulated site			0.5943
Douglas’s pouch	12 (50.0)	13 (48.1)
Perihepatic	7 (29.2)	10 (37.0)
Paracolic gutter	5 (20.8)	3 (11.1)
Intrapelvic	0	1 (3.7)
Amount of ascites (cm3)	17.3	55.4	0.0182
	(5.1-736.3)1	(9.3-494.1)1
Intravenous contrast (no)	5 (23.8)	4 (15.4)	0.4863
Time from onset (hours)	25.5 (6-144)1	17.7 (4-192)1	0.3402
CT attenuation values of ascites	22.5	16.5	0.0062
	(11.2-66.9)	(2.5-63.1)

¹Median (range);

²Mann-Whitney U test;

³Fisher’s exact test. CT: Computed tomography.

Table 2 Univariate and multivariate analysis of influencing factors on the computed tomography attenuation values of ascites

	Univariate		Multivariate
	Coefficient (95%CI)	P value	Coefficient (95%CI)	P value
Perforation site	8.86 (1.49-16.24)	0.020	7.39 (1.60-13.19)	0.014
Amount of ascites	-0.09 (-0.04-0.02)	0.513
Reason of perforation	1.57 (-4.64-7.77)	0.614
Ascites accumulated site	1.48 (-2.01-4.97)	0.397
Intravenous contrast	5.10 (-4.61-14.80)	0.296
Time from onset	-0.03 (-0.14-0.09)	0.656

Table 3 Logistic regression analysis of risk factors for postoperative complications

	Coefficient (95%CI)	P value
Age	1.04 (1.01-1.08)	0.026
Reason of perforation	1.50 (0.61-3.67)	0.374
Perforation site	3.40 (1.07-10.78)	0.038
CT attenuation values of ascites	1.03 (0.98-1.07)	0.247

CT: Computed tomography.

Table 4 Perforation site predicting rate of each method n (%)

	Site prediction rate
CT findings	42 (82.4)
CT attenuation values of ascites	40 (78.4)
Combining both methods	47 (92.2)

CT: Computed tomography.