Estimation of pancreatic histology and likelihood of postoperative pancreatic fistula using extracellular volume fraction from contrast-enhanced computed tomography

Table 1 Patient characteristics, n (%)/median (25^th-75^th percentiles)

Patient background	All (n = 71)
Age (years)	72 (62-78)
Sex
Male	38 (54)
Female	33 (46)
BMI	23.1 (20.4-25.1)
Indication
PDAC	29 (41)
Vater Ca	10 (14)
IPMN	10 (14)
Bile duct Ca	7 (10)
PanNEN	6 (8)
MCN	2 (3)
Other	7 (10)
Blood test findings
Hemoglobin (g/dL)	13.3 (12.2-14.0)
Hematocrit (%)	40.1 (37.2- 43.0)
Platelet (× 104/µL)	24.0 (19.1-28.4)
Creatinine (mg/dL)	0.68 (0.57-0.81)
Albmin (g/dL)	4.2 (4.0-4.4)
Prognostic Nutritional Index	49.0 (46.0-53.1)
Image findings
MPD diameter (mm)	3 (2-4)
Thickess of pancreas (mm)	13 (11-15)
CT value on precontrast (HU)	41.0 (38.1-44.4)
CT value on equilibrium phase (HU)	102.4 (92.5-113.4)
ECVf (%)	32.0 (27.1-36.7)
Operative and postoperative findings
Blood loss (mL)	370 (200-616)
Operative time (min)	590 (471-675)
Texture
Soft	51 (72)
Hard	20 (28)
Day 3 drain amylase (U/L)	304 (93-616)
Histologic findings
Area of acini (mm2)	0.879 (0.729-1.027)
Area of islets (mm2)	0.027 (0.019-0.037)
Area of fibrosis (mm2)	0.027 (0.013-0.092)
Area of fat (mm2)	0.030 (0.007-0.073)

BMI: Body mass index; PDAC: Pancreatic ductal adenocarcinoma; Vater Ca: Carcinoma of papilla of Vater; IPMN: Intraductal papillary mucinous neoplasm; Bile duct Ca: Bile duct cancer; Pan NEN: Pancreatic neuroendocrine neoplasm; MCN: Mucinous cystic neoplasm; MPD: Main pancreatic duct; ECVf: Extracellular volume fraction.

Table 2 Hard-texture vs soft-texture in imaging and histologic findings, median (25^th-75^th percentiles)

Patient background	Hard (n = 20)	Soft (n = 51)	P value
Imaging findings
MPD diameter (mm)	4 (2-5)	2 (2-3)	0.019
Thickess of pancreas (mm)	14 (12-15)	12 (10-15)	0.274
CT value in precontrast (HU)	40.0 (38.1-42.2)	41.7 (38.1-44.7)	0.140
CT value in equilibrium phase (HU)	113.5 (101.5-124.5)	99.5 (88.9-107.0)	0.001
ECVf (%)	39.9 (36.2-45.4)	30.3 (26.4-34.4)	< 0.001
Histological findings
Area of acini (mm2)	0.778 (0.514-1.027)	0.880 (0.805-1.027)	0.195
Area of islets (mm2)	0.028 (0.021-0.044)	0.027 (0.019-0.035)	0.222
Area of fibrosis (mm2)	0.100 (0.024-0.174)	0.019 (0.011-0.040)	< 0.001
Area of fat (mm2)	0.018 (0.005-0.070)	0.032 (0.008-0.073)	0.374

MPD: Main pancreatic duct; CT: Computed tomography; ECVf: Extracellular volume fraction.

Table 3 Patient characteristics of pancreaticoduodenectomy and univariate analysis of risk factors for postoperative pancreatic fistula, n (%)/median (25^th-75^th percentiles)

Patient background	All patients (n = 48)	non-POPF (n = 27)	POPF (n = 21)	P value
Age (years)	73 (64-78)	74 (66-79)	73 (63-77)	0.176
Sex				0.082
Male	27 (56)	12 (44)	15 (71)
Female	21 (44)	15 (56)	6 (29)
BMI	23.1 (20.3-24.8)	22.2(19.7-24.1)	23.7 (21.1-25.1)	0.154
Indication				0.382
PDAC	20 (42)	13 (48)	7 (33)
Non-PDAC	28 (58)	14 (52)	14 (67)
Blood test findings
Hemoglobin (g/dL)	13.3 (12.2-14.2)	13 (11.6-13.9)	13.9 (12.5-14.7)	0.058
Hematocrit (%)	40.1 (37.4-43.0)	39.5 (37.1-42.3)	41.0 (38.7-43.3)	0.216
Platelet (× 104/µL)	23.8 (19.5-28.6)	23.6 (17.9-28.5)	24.0 (20.8-31.3)	0.430
Creatinine (mg/dL)	0.66 (0.57-0.76)	0.64 (0.57-0.75)	0.68 (0.62-0.83)	0.266
Albmin (g/dL)	4.2 (3.8-4.3)	4 (3.7-4.2)	4.2 (4.1-4.4)	0.063
Prognostic nutritional index	48.1 (46.0-53.8)	47.1 (45.6-50.8)	51.0 (47.2-54.9)	0.099
Image findings
MPD diameter (mm)	3 (2-5)	4 (3-5)	2 (2-3)	0.001
Thickess of pancreas (mm)	13.5 (11-15)	13 (11-15)	14 (11.5-16)	0.530
CT value on precontrast (HU)	41.0 (37.8-44.2)	40.8 (37.7-42.7)	42.7 (37.2-46.0)	0.304
CT value on equilibrium phase (HU)	102.7 (92.7-116.2)	110.5 (100.9-125.2)	94.3 (88.3-103.9)	0.001
ECVf (%)	31.5 (27.3-39.1)	37.2 (28.6-46.1)	30.5 (26.2-32.5)	0.003
Operative and postoperative findings
Blood loss (mL)	462 (293-670)	440 (200-600)	540 (380-683)	0.053
Operative time (minute)	643 (574-690)	625 (566-680)	661 (597-734)	0.424
Texture				0.060
Soft	34 (71)	16 (59)	18 (86)
Hard	14 (29)	11 (41)	3 (14)
Day 3 drain amylase (U/L)	279 (82-638)	154 (24-373)	612 (261-2665)	< 0.001
Histologic findings
Area of acini (mm2)	0.847 (0.659-1.018)	0.802 (0.424-1.013)	0.880 (0.767-1.023)	0.127
Area of islets (mm2)	0.030 (0.019-0.037)	0.033 (0.019-0.041)	0.027 (0.018-0.036)	0.318
Area of fibrosis (mm2)	0.030 (0.014-0.122)	0.041 (0.017-0.191)	0.026 (0.011-0.081)	0.110
Area of fat (mm2)	0.026 (0.004-0.072)	0.014 (0.002-0.065)	0.035 (0.007-0.076)	0.232

POPF: Postoperative pancreatic fistula; BMI: Body mass index; PDAC: Pancreatic ductal adenocarcinoma; MPD: Main pancreatic duct; CT: Computed tomography; ECVf: Extracellular volume fraction.

Table 4 Multivariate analysis of risk factors for postoperative pancreatic fistula

	Odds ratio (95%CI)	P value
MPD diameter ≤ 2 mm	4.26 (1.01-17.94)	0.048
ECVf < 36%	11.07 (1.17-104.76)	0.036

MPD: Main pancreatic duct; ECVf: Extracellular volume fraction.

Table 5 Computed tomography risk score for postoperative pancreatic fistula

Score	Non-POPF	POPF	Rates	P value
CT risk score1				< 0.001
0	14	0	0%
1	7	7	50%
2	6	14	70%

¹Number of cases meeting two criteria. Main pancreatic duct diameter ≤ 2 mm and extracellular volume fraction < 36%. POPF: Postoperative pancreatic fistula; CT: Computed tomography.