Table 2.

Comparison of Clinical and CT imaging Characteristics between Type 1 AIP Patients with and without PaT

	AIP (n = 69)	AIP + PaC (n = 5)	P Value
Male	58 (84%)	2 (40%)	0.044
Age (year)	61 (24–80)	58 (42–76)	0.845
Surveillance period (month)	5 (1–109)	3 (0–6)	0.086
IgG4 (n = 65)			0.561
<1 time upper limit	8 (14%)	1 (20%)
1–2 times upper limit	11 (17%)	0 (0%)
≥ 2 times upper limit	41 (69%)	4 (80%)
CA-199 (n = 65, U/ml)	19.5 (2.0–1987.0)	21.4 (2.0–106.0)	0.767
Biopsy at the initial visit	41 (58%)	5 (100%)	0.150
Presence of extrapancreatic involvement
Bile duct	63 (91%)	3 (60%)	0.087
Kidney	25 (36%)	0 (0%)	0.160
Retroperitoneum	9 (9%)	2 (40%)	0.157
CT imaging characteristics of pancreatic parenchyma
Enlargement pattern			0.003
Diffuse	49 (71%)	0 (0%)
Focal	20 (29%)	5 (100%)
Presence of atrophy	10 (15%)	1 (20%)	0.564
Presence of heterogeneity	28 (41%)	5 (100%)	0.015
Presence of low-density (n = 26)	21 (30%)	5 (100%)	0.004
Mass-like low-density	6 (29%)	4 (80%)	0.055
Relative density of low-density
Arterial phase			1.000
Hypoattenuating	21 (100%)	5 (100%)
Isoattenuating	0 (0%)	0 (0%)
Hyperattenuating	0 (0%)	0 (0%)
Venous phase			0.562
Hypoattenuating	14 (67%)	4 (80%)
Isoattenuating	7 (33%)	1 (20%)
Hyperattenuating	0 (0%)	0 (0%)
Absolute density of low-density (Hu)
Pre-enhanced phase	42 (33–53)	45 (28–45)	0.769
Arterial phase	71 (51–96)	53 (32–89)	0.313
Venous phase	83 (57–112)	81 (37–94)	0.255
CT imaging characteristics of main pancreatic duct
Presence of dilatation	16 (23%)	1 (20%)	1.000
Presence of cutoff	31 (45%)	2 (40%)	1.000
CT imaging characteristics of peripancreatic structures
Presence of halo sign	43 (62%)	2 (40%)	0.374
Presence of stranding	14 (20%)	3 (60%)	0.076
Presence of ascites	2 (3%)	1 (20%)	0.192
Presence of vessel stricture	44 (64%)	4 (80%)	0.651

Abbreviations: AIP autoimmune pancreatitis, PaT pancreatic tumor, Hu Hounsfield

Quantitative data are expressed as median (range), qualitative data as absolute values (percentages)