Computed tomography-based transformer model for non-invasive prediction of portal venous pressure in chronic liver diseases

Table 1 Baseline characteristics of patients in all datasets, mean ± SD/n (%)

	Training set (n = 228)	Internal testing set (n = 57)	Temporally independent validation set (n = 74)	P value
Age (years)	51.5 ± 12.8	55.9 ± 15.0	55.2 ± 9.7	0.016
Gender
Male	148 (64.9)	31 (54.4)	42 (56.8)	0.218
Female	80 (35.1)	26 (45.6)	32 (43.2)
Etiology
Hepatitis B	113 (49.6)	18 (31.6)	39 (52.7)	0.152
Alcoholic	24 (10.5)	8 (14.0)	11(14.9)
Hepatitis C	8 (3.5)	1 (1.8)	2 (2.7)
Autoimmune	42 (18.4)	15 (26.3)	15 (20.3)
Others	41 (18.0)	15 (26.3)	7 (9.4)
Child-Pugh class
Class A	96 (42.1)	22 (38.6)	23 (31.1)	0.325
Class B	101 (44.3)	26 (45.6)	43 (58.1)
Class C	31 (13.6)	9 (15.8)	8 (10.8)
HVPG (mmHg)	17.9 ± 7.3	16.6 ± 10.3	15.9 ± 6.1	0.064
HVPG ≤ 5 mmHg	13 (5.7)	3 (5.3)	5 (6.8)
5 mmHg < HVPG < 10 mmHg	15 (6.6)	4 (7.0)	6 (8.1)
10 mmHg ≤ HVPG < 12 mmHg	10 (4.4)	3 (5.3)	3 (4.1)
12 mmHg ≤ HVPG < 16 mmHg	33 (14.5)	8 (14.0)	10 (13.5)
16 mmHg ≤ HVPG < 20 mmHg	50 (21.9)	14 (24.6)	15 (20.2)
HVPG ≥ 20 mmHg	107 (46.9)	25 (43.8)	35 (47.3)
Ascites
Yes	112 (49.1)	28 (49.1)	45 (60.8)	0.201
No	116 (50.9)	29 (50.9)	29 (39.2)
EGVB
Yes	199 (87.3)	38 (66.7)	62 (83.8)	< 0.001
No	29 (12.7)	19 (33.3)	12 (16.2)
Endoscopy therapy
No	77 (33.8)	29 (50.9)	33 (44.6)	0.109
1-2 sessions	115 (50.4)	21 (36.8)	32 (43.2)
3 and more sessions	36 (15.8)	7 (12.3)	9 (12.2)
Liver stiffness (kPa)	17.8 ± 9.0	15.2 ± 7.5	18.5 ± 7.3	0.186
Laboratory tests
Platelet (109/L)	71 ± 45.3	88 ± 62.6	70 ± 34.8	0.030
Total bilirubin (μmol/L)	27.9 ± 30.6	36.9 ± 47.5	27.4 ± 25.8	0.157
ALT (U/L)	37 ± 47.3	29 ± 27.7	35 ± 41.4	0.402
AST (U/L)	49 ± 52.2	39 ± 37.3	49 ± 49.5	0.396
ALP (U/L), median (IQR)	84 (56.8)	84 (87.0)	89 (60.5)	0.604
γ-GGT (U/L), median (IQR)	39 (59.8)	31 (65.0)	46 (85.5)	0.440
Albumin (g/L)	35.1 ± 6.2	35.7 ± 7.4	32.4 ± 5.1	0.002
Globulin (g/L)	28.5 ± 7.7	28.0 ± 7.3	30.6 ± 8.2	0.087
PT (seconds)	14.7 ± 2.4	14.0 ± 2.5	15.3 ± 2.9	0.018
INR	1.3 ± 0.2	1.2 ± 0.2	1.3 ± 0.3	0.080
Blood ammonia (μmol/L)	69.4 ± 36.7	58.8 ± 32.2	65.7 ± 36.9	0.220

HVPG: Hepatic vein pressure gradient; EGVB: Esophagogastric variceal bleeding; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; ALP: Alkaline phosphatase; γ-GGT: Gamma-glutamyl transferase; PT: Prothrombin time; INR: International normalized ratio; IQR: Interquartile range.

Table 2 Overall prediction accuracy of the model at different hepatic venous pressure gradient classification intervals

	Binary classification interval					Ternary classification interval					Quinary classification interval
	Set 1	Set 2	Set 3	Set 4	Set 5	Set 1	Set 2	Set 3	Set 4	Set 5	Set 1	Set 2	Set 3	Set 4	Set 5
Training set	91.8	93.1	91.9	94.6	95.4	88.1	87.3	85.3	91.4	94.0	73.1	71.9	68.8	77.4	85.0
Internal testing set	89.9	92.3	89.1	93.9	92.4	85.2	79.7	84.1	82.8	87.6	62.9	63.7	64.5	65.7	68.6
Temporally independent validation set	90.4	91.3	88.5	92.3	91.3	80.8	75.0	82.7	78.8	84.6	60.6	61.5	64.4	63.5	70.2

Table 3 Diagnostic performance of the model for different hepatic venous pressure gradient thresholds

HVPG	Group	Sensitivity (95%CI)	Specificity (95%CI)	PPV (95%CI)	NPV (95%CI)	AUC (95%CI)
> 5 mmHg	Training set	0.999 (0.998, 1.000)	0.817 (0.798, 0.834)	0.941 (0.935, 0.947)	0.998 (0.994, 0.999)	0.999 (0.999, 1.000)
	Internal testing set	0.990 (0.968, 0.997)	0.389 (0.183, 0.639)	0.964 (0.935, 0.981)	0.700 (0.354, 0.919)	0.956 (0.922, 0.991)
	Temporally independent validation set	0.967 (0.901, 0.992)	0.500 (0.223, 0.777)	0.937 (0.862, 0.974)	0.667 (0.309, 0.910)	0.951 (0.911, 0.991)
≥ 10 mmHg	Training set	0.986 (0.982, 0.989)	0.970 (0.963, 0.976)	0.983 (0.979, 0.987)	0.974 (0.968, 0.980)	0.998 (0.998, 0.999)
	Internal testing set	0.992 (0.970, 0.999)	0.519 (0.380, 0.655)	0.909 (0.868, 0.938)	0.933 (0.765, 0.988)	0.934 (0.905, 0.962)
	Temporally independent validation set	0.940 (0.859, 0.978)	0.857 (0.626, 0.962)	0.963 (0.888, 0.990)	0.783 (0.558, 0.917)	0.962 (0.927, 0.996)
≥ 12 mmHg	Training set	0.986 (0.982, 0.989)	0.990 (0.985, 0.993)	0.993 (0.991, 0.995)	0.978 (0.972, 0.983)	0.999 (0.999, 1.000)
	Internal testing set	0.996 (0.972, 1.000)	0.640 (0.531, 0.737)	0.875 (0.827, 0.912)	0.983 (0.895, 0.999)	0.978 (0.965, 0.991)
	Temporally independent validation set	0.912 (0.823, 0.961)	0.958 (0.769, 0.998)	0.986 (0.917, 0.999)	0.767 (0.573, 0.894)	0.972 (0.943, 1.000)
≥ 16 mmHg	Training set	0.938 (0.929, 0.946)	0.967 (0.961, 0.972)	0.958 (0.951, 0.965)	0.951 (0.944, 0.957)	0.993 (0.992, 0.994)
	Internal testing set	0.941 (0.899, 0.967)	0.853 (0.762, 0.914)	0.937 (0.894, 0.964)	0.862 (0.772, 0.921)	0.955 (0.922, 0.988)
	Temporally independent validation set	0.905 (0.809, 0.958)	0.833 (0.645, 0.937)	0.931 (0.839, 0.974)	0.781 (0.596, 0.901)	0.932 (0.877, 0.987)
≥ 20 mmHg	Training set	0.906 (0.891, 0.919)	0.969 (0.964, 0.973)	0.899 (0.883, 0.912)	0.971 (0.967, 0.975)	0.992 (0.991, 0.993)
	Internal testing set	0.793 (0.730, 0.845)	0.875 (0.796, 0.927)	0.920 (0.867, 0.954)	0.700 (0.616, 0.773)	0.895 (0.849, 0.940)
	Temporally independent validation set	0.750 (0.575, 0.873)	0.912 (0.811, 0.964)	0.818 (0.639, 0.924)	0.873 (0.768, 0.937)	0.904 (0.846, 0.961)

HVPG: Hepatic venous pressure gradient; PPV: Positive predictive value; NPV: Negative predictive value; AUC: Area under the receiver operating characteristic curve; CI: Confidence interval.