Artificial intelligence in liver ultrasound

Table 1 Studies using artificial intelligence based on ultrasound for fatty liver disease diagnosis

Task	Reference standard	Sample size	Method	Results	Ref.
Fatty liver disease diagnosis	Liver biopsy	55 patients with severe obesity, 38 of whom had fatty liver disease	Deep learning with B-mode image ultrasound	Sensitivity: 100%; specificity: 88%; accuracy: 96%; AUC: 0.98	[26]
Fatty liver disease diagnosis	Radiologist qualitative score	157 ultrasound liver images from unknown number of participants	Deep learning with B-mode image ultrasound	Sensitivity: 95%; specificity: 85%; accuracy: 90.6%; AUC: 0.96	[28]
NAFLD assessment	MRI proton density fat fraction	204 participants, 140 of whom had NAFLD, 64 control participants	One-dimensional CNNs	Sensitivity: 97%; specificity: 94%; accuracy: 96%; AUC: 0.98	[31]
NAFLD assessment	MRI proton density fat fraction	135 adult participants with known or suspected NAFLD	Transfer learning with a pretrained CNN by four ultrasound views of liver routinely obtained	SCC: 0.81; AUC: 0.91 (PDFF ≥ 5%)	[27]
NAFLD assessment	Liver biopsy	295 subjects, 198 mild fatty liver, one moderate degree of fatty liver	DCNN-based organ segmentation with Gaussian mixture modeling for automated quantification of the HRI	ICC of two radiologists and DCNN were 0.919, 0.916, 0.734	[33]
The severity of fatty liver	Abdominal ultrasound	21855 B-mode ultrasound images, 2070 patients with different severities from none to severe fatty liver	Pretrained CNN models with B-mode ultrasound images	The areas under the receiver operating characteristic curves were 0.974 (mild steatosis vs others), 0.971 (moderate steatosis vs others), 0.981 (severe steatosis vs others), 0.985 (any severity vs normal) and 0.996 (moderate-to-severe steatosis clinically abnormal vs normal-to-mild steatosis clinically normal)	[29]

AUC: Area under curve; CNN: Convolutional neural network; DCNN: Deep convolutional neural network; HRI: Hepato-renal index; ICC: Intraclass correlation; MRI: Magnetic resonance image; NAFLD: Nonalcoholic fatty liver disease; PDFF: Proton density fat fraction; SCC: Spearman correlation coefficient.