Complementary diagnostic value of conventional ultrasound and contrast-enhanced magnetic resonance imaging for post-hepatectomy hepatocellular carcinoma surveillance

Table 1 Baseline characteristics of the study population

Characteristic	Total (n = 186)	Recurrence (n = 68)	Non-recurrence (n = 118)
Age, years	56.8 ± 11.2	57.3 ± 10.8	56.5 ± 11.4
Male sex	158 (84.9)	59 (86.8)	99 (83.9)
HBV infection	162 (87.1)	60 (88.2)	102 (86.4)
Child-Pugh A	168 (90.3)	60 (88.2)	108 (91.5)
Tumor size, cm	5.2 ± 2.8	5.8 ± 3.1	4.9 ± 2.6
AFP, ng/mL	185.5 (28.7-756.3)	298.4 (56.2-1024.5)	142.8 (22.3-528.6)
Liver cirrhosis	148 (79.6)	58 (85.3)	90 (76.3)
Solitary tumor	142 (76.3)	48 (70.6)	94 (79.7)
Microvascular invasion	52 (28.0)	28 (41.2)	24 (20.3)
ALT, U/L	42.6 ± 28.3	45.8 ± 31.2	40.7 ± 26.5
Albumin, g/L	38.5 ± 4.8	37.8 ± 5.1	38.9 ± 4.6

Data are presented as mean ± SD, n (%), or median (interquartile range).

AFP: Alpha-fetoprotein; ALT: Alanine aminotransferase; HBV: Hepatitis B virus.

Table 2 Overall diagnostic performance of different imaging modalities

Parameter	US alone	CE-MRI alone	Combined
Sensitivity, %	61.8 (49.2-73.3)	92.6 (83.7-97.6)	97.1 (89.8-99.6)
Specificity, %	93.2 (87.1-97.0)	95.8 (90.4-98.6)	96.6 (91.6-99.1)
PPV, %	84.0 (70.9-92.8)	92.6 (83.7-97.6)	94.3 (86.0-98.4)
NPV, %	81.5 (73.4-87.9)	95.8 (90.4-98.6)	98.3 (93.8-99.8)
Accuracy, %	82.3 (76.0-87.5)	94.6 (90.3-97.4)	96.8 (93.1-98.8)
AUC	0.775 (0.708-0.834)	0.942 (0.897-0.971)	0.969 (0.932-0.989)
Detection rate, %	61.8 (42/68)	92.6 (63/68)	97.1 (66/68)
Positive LR	9.09 (5.12-16.13)	22.05 (11.36-42.78)	28.56 (13.12-62.19)
Negative LR	0.41 (0.30-0.56)	0.08 (0.03-0.18)	0.03 (0.01-0.12)
Youden index	0.550 (0.417-0.683)	0.884 (0.793-0.952)	0.937 (0.872-0.978)
F1 score	0.716 (0.612-0.808)	0.926 (0.867-0.964)	0.957 (0.911-0.983)

Data are presented as point estimate (95% confidence interval), with the exception of the detection rate.

AUC: Area under the curve; CE-MRI: Contrast-enhanced magnetic resonance imaging; LR: Likelihood ratio; NPV: Negative predictive value; PPV: Positive predictive value; US: Ultrasound.

Table 3 Diagnostic performance stratified by lesion size

Lesion size, cm	n	US sensitivity, %	CE-MRI sensitivity, %	P value
< 1	13	38.5 (13.9-68.4)	87.5 (61.7-98.4)	< 0.001
1-2	28	60.7 (40.6-78.5)	89.3 (71.8-97.7)	< 0.001
> 2	35	85.7 (69.7-95.2)	97.1 (85.1-99.9)	0.065
2-3	15	80.0 (51.9-95.7)	93.3 (68.1-99.8)	0.091
3-5	12	91.7 (61.5-99.8)	100.0 (73.5-100.0)	0.478
> 5	8	87.5 (47.3-99.7)	100.0 (63.1-100.0)	0.302
Overall	76	61.8 (49.2-73.3)	92.6 (83.7-97.6)	< 0.001

Data are presented as sensitivity (95% confidence interval).

CE-MRI: Contrast-enhanced magnetic resonance imaging; US: Ultrasound.

Table 4 Diagnostic performance stratified by lesion location

Lesion location	n	US sensitivity (%)	CE-MRI sensitivity (%)	P value
Superficial subcapsular	27	88.9 (70.8-97.6)	72.2 (52.8-87.3)	0.032
Deep parenchymal	41	52.4 (36.4-68.0)	95.2 (83.8-99.4)	< 0.001
Near surgical margin	18	72.2 (46.5-90.3)	88.9 (65.3-98.6)	0.045
Dome region (VII/VIII)	14	42.9 (17.7-71.1)	92.9 (66.1-99.8)	0.003
Caudate lobe (Seg I)	8	37.5 (8.5-75.5)	87.5 (47.3-99.7)	0.021
Right posterior section	12	50.0 (21.1-78.9)	91.7 (61.5-99.8)	0.008

Data are presented as sensitivity (95% confidence interval).

Superficial subcapsular: Lesions < 2 cm from the liver capsule; deep parenchymal: Lesions ≥ 2 cm from the liver capsule.

CE-MRI: Contrast-enhanced magnetic resonance imaging; Seg: Segment; US: Ultrasound.

Table 5 Detection of vascular invasion

Vascular invasion type	n	US detection (%)	CE-MRI detection (%)	P value
PVTT	16	62.5 (35.4-84.8)	93.8 (69.8-99.8)	0.012
Hepatic vein invasion	5	40.0 (5.3-85.3)	100.0 (47.8-100.0)	0.025
Bile duct invasion	7	42.9 (9.9-81.6)	85.7 (42.1-99.6)	0.035
Inferior vena cava invasion	3	33.3 (0.8-90.6)	100.0 (29.2-100.0)	0.046
Microvascular invasion (imaging)	22	45.5 (24.4-67.8)	86.4 (65.1-97.1)	0.002
Multiple vascular invasion	9	44.4 (13.7-78.8)	88.9 (51.8-99.7)	0.023

Data are presented as detection rate (95% confidence interval).

CE-MRI: Contrast-enhanced magnetic resonance imaging; PVTT: Portal vein tumor thrombus; US: Ultrasound.

Table 6 Comparative imaging characteristics and advantages

Characteristic	Conventional US	CE-MRI
Spatial resolution	Excellent for superficial lesions	Excellent for deep lesions
Soft tissue contrast	Moderate	Superior
Small lesion detection	Limited (< 1 cm)	Excellent (< 1 cm)
Vascular assessment	Limited (Doppler)	Comprehensive
Real-time capability	Yes	No
Cost-effectiveness	High	Moderate
Availability	Widespread	Limited in some areas
Operator dependency	High	Low

CE-MRI: Contrast-enhanced magnetic resonance imaging; US: Ultrasound.