Ultrasound elastography for the differential diagnosis of benign and malignant gastrointestinal stromal tumors

Table 1 Demographic and clinical characteristics of the study population, mean ± SD/n (%)

Characteristic	All patients (n = 100)	Benign GIST (n = 43)	Malignant GIST (n = 57)	P value
Age (years)	62.3 ± 11.4	60.8 ± 12.1	63.5 ± 10.8	0.235
Sex				0.412
Male	57 (57.0)	23 (53.5)	34 (59.6)
Female	43 (43.0)	20 (46.5)	23 (40.4)
Tumor location				0.028
Stomach	65 (63.1)	33 (73.3)	32 (55.2)
Small intestine	28 (27.2)	8 (17.8)	20 (34.5)
Other	10 (9.7)	4 (8.9)	6 (10.3)
Tumor size (cm)	4.8 ± 2.9	3.2 ± 1.4	6.1 ± 3.1	< 0.001
Presenting symptoms				0.156
Asymptomatic	42 (42.0)	22 (51.2)	20 (35.1)
Abdominal pain	35 (35.0)	13 (30.2)	22 (38.6)
GI bleeding	15 (15.0)	5 (11.6)	10 (17.5)
Other	8 (8.0)	3 (7.0)	5 (8.8)

GIST: Gastrointestinal stromal tumor.

Table 2 Conventional ultrasound features of benign and malignant gastrointestinal stromal tumors, n (%)

Feature	Benign GIST (n = 45)	Malignant GIST (n = 58)	P value
Shape			< 0.001
Regular	38 (84.4)	25 (43.1)
Irregular	7 (15.6)	33 (56.9)
Boundary			0.002
Clear	41 (91.1)	39 (67.2)
Unclear	4 (8.9)	19 (32.8)
Echo pattern			< 0.001
Homogeneous	36 (80.0)	22 (37.9)
Heterogeneous	9 (20.0)	36 (62.1)
Vascularity			< 0.001
Grade 0-1	35 (77.8)	19 (32.8)
Grade 2-3	10 (22.2)	39 (67.2)

GIST: Gastrointestinal stromal tumor.

Table 3 Strain elastography parameters for benign and malignant gastrointestinal stromal tumors, mean ± SD/n (%)

Parameter	Benign GIST (n = 45)	Malignant GIST (n = 58)	P value
Elastographic pattern			< 0.001
Score 1-2	33 (73.3)	8 (13.8)
Score 3	9 (20.0)	15 (25.9)
Score 4-5	3 (6.7)	35 (60.3)
Strain ratio	2.31 ± 0.89	4.82 ± 1.73	< 0.001
Strain pattern			< 0.001
Homogeneous	38 (84.4)	20 (34.5)
Heterogeneous	7 (15.6)	38 (65.5)

GIST: Gastrointestinal stromal tumor.

Table 4 Shear-wave elastography parameters for benign and malignant gastrointestinal stromal tumors, mean ± SD

Parameter	Benign GIST (n = 45)	Malignant GIST (n = 58)	P value
Mean elastic modulus (kPa)	21.3 ± 8.4	45.6 ± 15.8	< 0.001
Maximum elastic modulus (kPa)	28.7 ± 10.2	62.4 ± 20.3	< 0.001
Minimum elastic modulus (kPa)	15.2 ± 6.8	31.8 ± 12.4	< 0.001
Heterogeneity index	0.18 ± 0.07	0.42 ± 0.15	< 0.001

GIST: Gastrointestinal stromal tumor.

Table 5 Diagnostic performance of elastography parameters

Parameter	AUC (95%CI)	Cutoff value	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
Strain ratio	0.892 (0.831-0.953)	3.45	84.5	86.7	89.1	81.2
Mean elastic modulus	0.918 (0.865-0.971)	32.5	87.9	88.9	91.1	85.1
Heterogeneity index	0.876 (0.810-0.942)	0.28	82.8	84.4	87.3	79.2

AUC: Area under the curve; CI: Confidence interval; NPV: Negative predictive value; PPV: Positive predictive value.