Endoscopic ultrasound elastography for malignant pancreatic masses and associated lymph nodes: Critical evaluation of strain ratio cutoff value

Table 1 Classification of pancreatic lesions

	Malignant	Nonmalignant
Solid	Adenocarcinoma	Acute pancreatitis
	Lymphoma	Chronic pancreatitis
	PNETs	Adenoma
	Pancreatoblastoma	Insulinoma
	Metastatic cancer
Solid-Cystic	Mucinous cystadenoma1	Serous cystadenoma
	Serous cystadenocarcinoma
	Mucinous cystadenocarcinoma
	IPMN1

¹Considered malignant if the Fukuoka criteria are met.

PNET: Pancreatic neuroendocrine tumor; IPMN: Intraductal papillary mucinous neoplasm.

Table 2 Baseline data and endoscopic ultrasound elastography diagnostic outcomes of pancreatic masses

	Malignancy (n = 69)	Nonmalignancy (n = 52)	P value
Age (yr), median (range)	67 (13–93)	68 (20–99)	0.8907a
Sex (female), n (%)	36 (52.2)	19 (36.5)	0.1271b
PM location, n (%)			0.6891b
Head	50 (72.5)	35 (67.3)
Neck	3 (4.3)	4 (7.7)
Body	13 (18.8)	12 (23.1)
Tail	3 (4.3)	1 (1.9)
PM diameter (mm), median (range)	37.0 (7.4–70.0)	30 (10.0–60.0)	0.0616a
Giovannini elastic score, n (%)			< 0.001b
Green (score 1 to 2)	-	11 (21.2)
Cyan (score 3)	5 (7.2)	11 (21.2)
Dark blue (score 4 to 5)	64 (92.8)	30 (57.7)
Strain ratio, median (range)	50.4 (7.8–225.0)	33.0 (2.6–321.0)	< 0.001a
Firmness/histopathology, n (%)			< 0.001b
Solid-cystic masses (n = 36)	26/69	10/52	< 0.001b
Serous cystadenoma	-	10 (19.2)
Mucinous cystadenoma	5 (7.2)	-
Mucinous cystadenocarcinoma	3 (4.3)	-
IPMN	18 (26.1)	-
Solid masses (n = 85)	43/69	42/52	< 0.001b
Normal	-	4 (7.7)
Acute pancreatitis	-	10 (19.2)
Chronic pancreatitis	-	26 (50.0)
Adenoma	-	1 (1.9)
Insulinoma	-	1 (1.9)
Adenocarcinoma	33 (47.8)	-
Lymphoma	3 (4.3)	-
PNETs	6 (8.7)	-
Pancreatoblastoma	1 (1.4)	-

^aMann-Whitney U test.

^bPearson Chi-Quadrat Test.

IPMN: Intraductal papillary mucinous neoplasm; PNET: Pancreatic neuroendocrine tumor; PM: Pancreatic masses.

Table 3 Qualitative and quantitative diagnostic accuracy of endoscopic ultrasound elastography for detecting malignant pancreatic masses: All lesions (n = 121) and only solid pancreatic masses (n = 85)

	EUS-elastography qualitative analysis		EUS-elastography quantitative analysis
	All masses	Only solid pancreatic masses	All PMs		Only solid PMs
			SR ≥ 21.51	SR ≥ 121.02	SR ≥ 21.51	SR ≥ 121.02
Sensitivity (%)	100.0	100.0	94.2	14.5	90.7	14.0
Specificity (%)	21.2	23.8	40.4	96.2	47.6	95.4
PPV (%)	62.7	57.3	67.7	83.3	63.9	70.0
NPV (%)	100.0	100.0	84.0	45.9	83.3	52.0
Accuracy (%)	66.1	62.4	71.1	49.6	69.4	54.1

¹Internally derived optimal strain ratio (SR) cutoff for sensitivity (and accuracy).

²Internally derived optimal SR cutoff for specificity.

EUS: Endoscopic ultrasound; SR: Strain ratio; PPV: Positive predictive value; NPV: Negative predictive value; PM: Pancreatic masses.

Table 4 Baseline data, endoscopic ultrasound, and endoscopic ultrasound elastography diagnostic outcomes of the associated lymph nodes

	Malignancy (n = 22)	Nonmalignancy (n = 21)	P value
Age (yr), median (range)	76 (57–95)	65 (39–85)	0.2037a
Sex (female), n (%)	8 (36.4)	6 (28.6)	0.5860b
LN location, n (%)			0.4250b
Esophagus	13 (59.1)	15 (71.4)
Stomach	2 (9.1)	1 (4.8)
Liver	1 (4.5)	-
Pancreas	5 (22.7)	5 (23.8)
Kidney	1 (4.5)	-
LN diameter, median (range)	20.0 (4.0–50.0)	15.5 (7.0–21.6)	0.2662a
EUS-LN characteristics, n (%)
Irregular shape	11 (50.0)	10 (47.6)	0.8760b
Undefined border	13 (59.1)	8 (38.1)	0.2730b
Anechoic density	7 (31.8)	3 (14.3)	0.1740b
Giovannini elastic score, n (%)			0.7970b
Green (score 1 to 2)	1 (4.5)	2 (9.5)
Cyan (score 3)	6 (27.3)	6 (28.6)
Dark blue (score 4 to 5)	15 (68.2)	13 (61.9)
Strain ratio, median (range)	30.0 (3.0–120.0)	40.0 (5.0–269.0)	0.7182a
Histopathology, n (%)			< 0.001b
Acute lymphadenitis	-	10 (47.6)
Chronic lymphadenitis	-	11 (52.4)
Lymphoma	2 (9.1)	-
Metastasis	20 (90.9)	-

^aMann-Whitney U test.

^bPearson Chi-Quadrat Test.

EUS: Endoscopic ultrasound; LN: Lymph node.

Table 5 Diagnostic accuracy of conventional B-mode endoscopic ultrasound and qualitative and quantitative endoscopic ultrasound elastography analysis for malignancy in the associated lymph nodes (n = 43)

	Conventional B-mode EUS				EUS-elastography qualitative analysis	EUS-elastography quantitative analysis
	Size	Shape	Border	Density		SR ≥ 14.01	SR ≥ 155.02
Sensitivity (%)	59.1	50.0	59.1	31.8	68.1	90.9	4.5
Specificity (%)	42.9	52.4	61.9	85.7	38.1	28.6	95.2
PPV (%)	52.0	52.4	61.9	70.0	53.6	51.4	50.0
NPV (%)	50.0	50.0	59.1	54.6	53.3	75.0	48.8
Accuracy (%)	51.2	51.2	60.5	58.1	53.5	60.4	48.8

¹Internally derived optimal strain ratio cutoff for sensitivity (and accuracy).

²Internally derived optimal cutoff for specificity.

EUS: Endoscopic ultrasound; SR: Strain ratio; PPV: Positive predictive value; NPV: Negative predictive value.