Ultrasound-based techniques for the diagnosis of liver steatosis

Table 1 Quantitative ultrasound: Optimal cutoffs obtained using proton density fat fraction with magnetic resonance imaging as the reference standard

Technique	S0 vs S1–S3	S0–S1 vs S2–S3	S0–S2 vs S3
BSC[20], 1/cm-sr (NAFLD)	0.0038	---------	---------
	Sensitivity: 93%	---------	---------
	Specificity: 97%	---------	---------
CAP[30], dB/m (NAFLD)	288	---------	---------
	Sensitivity: 75%
	Specificity: 77%
ATI[40], dB/cm/MHz (NAFLD)	0.63	0.72	---------
	Sensitivity: 80%	Sensitivity: 100%	---------
	Specificity: 89%	Specificity: 78%	---------
UGAP[43], dB/cm/MHz (NAFLD)	0.63	0.68	0.74
	Sensitivity: 80%	Sensitivity: 83%	Sensitivity: 87%
	Specificity: 91%	Specificity: 74%	Specificity: 79%
SSE[46], mm/μs (not specified)	1.537	1.511	---------
	Sensitivity: 80%	Sensitivity: 100%	---------
	Specificity: 86%	Specificity: 96%	---------

In parenthesis: Etiology of liver disease. BSC: Backscatter coefficient; sr: Square radian; CAP: Controlled attenuation parameter; dB: Decibel; ATI: Attenuation imaging; MHz: Megahertz; UGAP: Ultrasound guided attenuation parameter; SSE: Sound speed estimation; NAFLD: Non-alcoholic fatty liver disease.