A Modified Targetoid Feature Emphasizing Thin-Rim APHE to Improve the Diagnostic Performance of LI-RADS for Malignant Hepatic Tumors

Figures & data

Figure 1 Flowchart of the study. HCC, hepatocellular carcinoma; LR-M, LI-RADS M.

Table 1 Demographic and Pathological Characteristics of 381 Patients with 387 Hepatic Tumors

Parameter	Value
No. of participants	n=381
Mean age (years old)	52.9±21.4
Male/Female	323/58
Cause of chronic liver disease
Hepatitis B virus	373
Hepatitis C virus	3
Alcoholic liver disease	3
Nonalcoholic steatohepatitis	2
Liver cirrhosis	215
No. of Observations	387
Observation size (mm)	49.2±27.2
<20	38
≥20	349
Final diagnosis
HCC	281
Non-HCC malignancy	86
ICC	51
cHCC-CC	31
Metastasis	2
EHE	2

Note: Continuous variables are described as median with interquartile range in parenthesis. Categorical variables are described as number of participants.

Abbreviations: ICC, Intrahepatic cholangiocarcinoma; cHCC-CC: Combined hepatocellular-cholangiocarcinoma; EHE, Epithelioid hemangioendothelioma.

Figure 2 Rim hyperenhancement patterns on AP image and the modified measurement criterion of rim APHE. (a) Rim hyperenhancement patterns on AP image, thick-rim(left) and thin-rim(right). (b) the modified measurement criterion of rim APHE. Hepatic observations with rim APHE (spatially defined subtype of APHE in which arterial phase enhancement is most pronounced in the periphery) were divided into two categories, thick-rim (30–70%) and thin-rim APHE (< 30%). The thickness measurement of the rim APHE compared with the tumor radius is T/R=30%-70%, classified as thick-rim APHE (left). The thickness measurement of the rim APHE compared with the tumor radius is T/R<30%, classified as thin-rim APHE(right).

Table 2 Liver Imaging-Reporting and Data System (LI-RADS v2018) Categorization of HCC and Non-HCC Malignancies Using Contrast-Enhanced MRI

Category	HCC malignancy (n=281)	Non-HCC malignancy (n=86)	Benign lesions (n=20)
LR-3	0	2 (2.3)	13 (65.0)
LR-4	12 (4.3)	0	5 (25.0)
LR-5	212 (75.4)	10 (11.6)	2 (10.0)
LR-M	57 (20.3)	74 (86.0)	0

Note: Data in parenthesis are presented as percentage.

Abbreviations: HCC, Hepatocellular carcinoma; LR-3(LI-RADS-3), Intermediate probability of HCC; LR-4(LI-RADS-4), Probably HCC; LR-5(LI-RADS-5), Definitely HCC; LR-M(LI-RADS-M), Definitely or probably malignant.

Table 3 MRI Features of Malignant Observations According to MRI Modality (ECA-MRI Vs HBA-MRI)

LI-RADS features	HCC (n=281)			Non-HCC malignancy (n=86)
	ECA-MRI (n=150)	HBA-MRI (n=131)	P value	ECA-MRI (n=55)	HBA-MRI (n=31)	P value
Major features
Non-rim APHE	125 (83.3)	105 (80.2)	0.490	19 (34.5)	9 (29.0)	0.241
Non-peripheral washout	122 (81.3)	105 (80.2)	0.802	12 (21.8)	6 (19.4)	0.787
Enhancing capsule	134 (89.3)	80 (61.1)	<0.001	8 (14.5)	3 (9.7)	0.739
Targetoid appearance
Rim APHE	24 (16.0)	26 (19.8)	0.400	34 (61.8)	22 (71.0)	0.393
			0.130			0.184
Thick rim	22 (91.7)	17 (65.4)		4 (11.8)	1 (4.5)
Thin rim	2 (8.4)	9 (34.6)		29 (85.3)	21 (95.5)
Peripheral washout	19 (12.7)	25 (19.1)	0.140	20 (36.4)	15 (48.4)	0.276
Delayed central enhancement	13 (8.7)	8 (6.1)	0.416	40 (72.7)	17 (54.8)	0.092
Targetoid DWI	6 (4.0)	7 (5.3)	0.601	17 (30.9)	15 (48.4)	0.107
Targetoid TP/HBP	NA	7 (5.3)		NA	22 (71.0)

Note: Data in parenthesis are presented as percentage.

Abbreviations: HCC, Hepatocellular carcinoma; ECA-MRI, Extracellular contrast agent–enhanced MRI; HBA-MRI, Hepatobiliary agent–enhanced MRI; APHE, Arterial phase hyperenhancement; DWI, Diffusion-weighted imaging; TP, Transitional phase; HBP, Hepatobiliary phase; NA, Not applicable/available.

Table 4 Comparison of LI-RADS Characteristic of the Study Population Within LR-M Category

LI-RADS features	HCC (n=57)	Non-HCC malignancy (n=74)	OR (univariable)	OR (multivariable)
Major features
Non-rim APHE	7 (12.3)	14 (18.9)	1.69 (0.65–4.78, p=0.29)
Non-peripheral washout	5 (8.8)	8 (10.8)	0.78 (0.22–2.48, p=0.68)
Enhancing capsule	36 (63.2)	8 (10.8)	13.93 (5.85–36.71, p<0.001)	8.38 (2.66–30.55, p=0.001)
Targetoid appearance
Rim APHE	50 (87.7)	56 (75.7)	0.43 (0.16–1.07, p=0.08)
Thick rim	39 (68.4)	5 (6.8)	0.03 (0.01–0.09, p<0.001)	0.07 (0.01–0.30, p=0.001)
Thin rim	11 (19.3)	51 (68.9)	0.10 (0.04–0.23, p<0.001)	0.08 (0.02–0.24, p<0.001)
Peripheral washout	44 (77.2)	35 (47.3)	0.27 (0.12–0.58, p=0.001)	0.08 (0.02–0.31, p<0.001)
Delayed central enhancement	21 (36.8)	57 (77.0)	6.11 (2.87–13.55, p<0.001)
Targetoid DWI	13 (22.8)	32 (43.2)	2.64 (1.24–5.86, p=0.014)	7.02 (1.89–30.42, p=0.005)
Targetoid TP/HBP	7/28 (25.0)	22/29(75.9)	0.32 (0.13–0.73, p=0.009)
Ancillary features
Surface retraction	9 (15.8)	27 (36.5)	0.40 (0.14–1.03, p=0.068)
Bile duct dilatation	4 (7.0)	23 (31.1)	0.16 (0.05–0.46, p=0.002)
Lobulated margin	17 (29.8)	33 (44.6)	1.94 (0.94–4.09, p=0.075)

Note: Data in parenthesis are presented as percentage.

Abbreviations: HCC, Hepatocellular carcinoma; APHE, Arterial phase hyperenhancement; DWI, Diffusion-weighted imaging; TP, Transitional phase; HBP, Hepatobiliary phase.

Figure 3 Hepatocellular carcinoma in a 74-year-old man with chronic hepatitis B. (a-c) On the axial arterial phase, portal venous phase and delayed phase images after administration of extracellular contrast agent, the segment-5 lesion showed thick-rim arterial phase hyperenhancement (APHE) followed by non-peripheral washout. (d) The mass showed a non-targetoid appearance on b-800 diffusion weighted image. The tumor was initially categorized as LR-M by observers. The tumor was re-categorized as modified LR-5 according to modified LI-RADS.

Figure 4 Intrahepatic cholangiocarcinoma in two patients, a 48-year-old man with chronic hepatitis B. On the axial arterial phase image (a), the liver mass on segment 5 showed thin-rim arterial phase hyperenhancement (APHE). On portal venous phase and delayed phase images (b and c) after administration of extracellular contrast agent, the tumor showed delayed central enhancement. On b-800 DWI image (d), the mass showed a targetoid appearance. The tumor was initially categorized as LR-M by observers. The tumor was re-categorized as modified LR-M according to modified LI-RADS.

Figure 5 Performance of thin-rim APHE, targetoid DWI and peripheral washout to distinguish non-HCC malignancy from HCC in targetoid lesions.

Table 5 Diagnostic Performance of LI-RADS Categories for the Diagnosis of Hepatic Malignancies Using Enhanced MRI

	TP	FN	FP	TN	Sensitivity (95% CI)	Specificity (95% CI)	Accuracy (95% CI)	PPV (95% CI)	NPV (95% CI)
LR-M	74	12	57	244	86.0 (78.6–93.5)	81.1 (76.6–85.5)	82.2 (78.3–86.0)	56.5 (47.9–65.1)	95.3 (92.7–97.9)
mLR-M	71	15	32	269	82.2 (74.4–90.7)	89.4 (85.9–92.9)	87.9 (84.6–91.1)	68.9 (59.8–78.0)	94.7 (92.1–97.3)
P value					0.529	0.004	0.027	NA	NA
LR-5	224	57	20	86	79.7 (75.0–84.4)	81.1 (73.6–88.7)	80.1 (76.1–84.1)	91.8 (88.3–95.3)	60.1 (52.0–68.3)
mLR-5	249	32	23	83	88.6 (84.9–92.3)	78.3 (70.3–86.3)	85.8 (82.3–89.3)	91.5 (88.2–94.9)	72.2 (63.9–80.5)
P value					0.004	0.608	0.036	NA	NA

Note: Data are described as percentage with 95% confidence interval in parenthesis.

Abbreviations: TP, True positive; FN, False negative; FP, False-positive; TN, True negative; CI, Confidence interval; PPV, Positive predictive value; NPV, Negative predictive value; LR-M, LI-RADS M; mLR-M, Modified LI-RADS M; mLR-5, Modified LI-RADS 5; NA, Not applicable.