Table 2. Results of meta-regression analysis of the sensitivity and specificity of contrast-enhanced ultrasound LR-5 for diagnosing hepatocellular carcinoma.

Covariates	Subgroup	No. of experts reading	Meta-analysis summary estimate
			Sensitivity	P value	Specificity	P value
Study design	Cohort	19	0.67 (95% CI: 0.61–0.74)	0.48	0.89 (95% CI: 0.83–0.94)	0.58
	Case control	1	0.57 (95% CI: 0.47–0.67)		0.96 (95% CI: 0.91–0.99)
Study type	Retrospective	17	0.67 (95% CI: 0.60–0.73)	0.88	0.89 (95% CI: 0.83–0.95)	0.92
	Prospective	3	0.68 (95% CI: 0.53–0.83)		0.90 (95% CI: 0.81–0.99)
Center	Single center	13	0.72 (95% CI: 0.65–0.80)	0.009	0.87 (95% CI: 0.79–0.95)	0.35
	Multi-center	7	0.57 (95% CI: 0.52–0.62)		0.93 (95% CI: 0.83–0.99)
No. of patients	<100	11	0.62 (95% CI: 0.53–0.70)	0.056	0.87 (95% CI: 0.78–0.95)	0.367
	≥100	9	0.73 (95% CI: 0.67–0.79)		0.92 (95% CI: 0.86–0.98)
No. of lesions	<100	11	0.62 (95% CI: 0.53–0.70)	0.056	0.87 (95% CI: 0.78–0.95)	0.367
	≥100	9	0.73 (95% CI: 0.67–0.79)		0.92 (95% CI: 0.86–0.98)
Number of US systems	Single system	14	0.66 (95% CI: 0.59–0.74)	0.792	0.87 (95% CI: 0.81–0.94)	0.387
	Multiple systems	6	0.68 (95% CI: 0.58–0.79)		0.93 (95% CI: 0.88–0.98)
Contrast agent	SonoVue	18	0.67 (95% CI: 0.61–0.73)	0.924	0.88 (95% CI: 0.81–0.94)	<0.001
	SonoVue & Sonozoid	2	0.66 (95% CI: 0.41–0.91)		1.00
LI-RADS version	v. 2016	6	0.72 (95% CI: 0.59–0.85)	0.281	0.77 (95% CI: 0.63–0.91)	0.058
	v. 2017	14	0.65 (95% CI: 0.58–0.71)		0.94 (95% CI: 0.92–0.96)
Reference standard	Pathology only	9	0.60 (95% CI: 0.54–0.66)	0.035	0.92 (95% CI: 0.90–0.94)	0.331
	Pathology & imaging & follow-up	11	0.73 (95% CI: 0.64–0.81)		0.86 (95% CI: 0.77–0.96)

CI, confidence interval; US, ultrasound; LI-RADS, Liver Imaging Reporting and Data System.