Table 4. Diagnostic accuracy of PDFF for classifying steatosis.

Cross-sectional steatosis grade classification (n=113)	MRI PDFF threshold (%) at 90% specificity		Sensitivity	PPV	NPV	AUROC (95% CI)
0-1 vs 2-3	16.3		83% (62/75)	95% (62/65)	73% (35/48)	0.95 (0.91–0.98)
0-2 vs 3	21.7		84% (26/31)	76% (26/34)	94% (74/79)	0.96 (0.93–0.99)
Longitudinal steatosis grade change classification (n=78)	Mean (SD) PDFF change (%)	Cutoff PDFF change at 90% specificity (%)	Sensitivity	PPV	NPV	AUROC (95% CI)
Decrease in steatosis grade (improvement) (42%)	-7.4±8.7	- 5.1	58% (19/33)	83% (19/23)	75% (41/55)	0.81 (0.71–0.91)
No change in steatosis grade (49%)	0.3±6.3	-	-	-	-	-
Increase in steatosis grade (worsening) (9%)	7.7±6.0	5.6	57% (4/7)	36% (4/11)	96% (64/67)	0.81 (0.63–0.99)

Notes: PDFF = proton density fat fraction; MRI = magnetic resonance imaging; PPV = positive predictive value; NPV = negative predictive value; AUROC = area under ROC curve; CI = confidence interval