Apparent diffusion coefficient-based histogram analysis differentiates histological subtypes of periampullary adenocarcinoma

Table 1 Characteristics of patients enrolled in the two histological groups

	IPAC	PPAC	P value
Total (n)	17	23
Age, yr (mean ± SD)	58.1±8.4	57.8±7.8	0.929
Male/female, n	12/5	14/9	0.524
CA19-9 positive (n)	9	15	0.433
Size, mm (mean ± SD)	15.5±5.1	17.4±5.7	0.273
Tumor differentiation	4/10/3	2/13/8	0.288
Well/moderate/poor (n)
Nodal involvement (n)	4	5	0.893
Perineural invasion (n)	1	9	0.016
Vessel involvement (n)	2	3	0.904

CA19-9 > 34 U/mL was defined as positive. IPAC: Intestinal-type periampullary adenocarcinoma; PPAC: Pancreatobiliary-type periampullary adenocarcinoma; SD: Standard deviation; n: Number; CA19-9: Carbohydrate antigen 19-9.