Table 1.

Percent CT number accuracy and percent noise reduction observed in five clinical cases. Both CT number and standard deviation are measured in a ROI (20 × 20 pixels) in the relative smooth liver region, such as those shown in Figures 4 and 5. ACNR: anticorrelated noise reduction [12].

Dataset	Basis material	Algorithm	Mean density (mg/cc)	Standard deviation	Absolute density error (mg/cc)	% Density error	% Noise reduction
Case 1  (Figure 4)	Water	Original	29.16	72.22	—	—	—
		ACNR	26.00	24.26	3.16	10.8%	66.4%
		Proposed	27.85	30.29	1.31	4.5%	58.1%
	Iodine	Original	−961.41	29.71	—	—	—
		ACNR	−961.22	9.45	0.19	0.002%	68.2%
		Proposed	−961.33	10.32	0.08	0.008%	65.3%
Case 2  (Figure 5)	Water	Original	15.28	88.27	—	—	—
		ACNR	24.25	27.99	8.97	58.7%	68.3%
		Proposed	15.42	28.17	0.14	0.9%	68.0%
	Iodine	Original	−967.92	31.42	—	—	—
		ACNR	−967.41	9.83	0.51	0.05%	68.7%
		Proposed	−966.31	10.98	0.61	0.2%	65.1%
Case 3	Water	Original	5.74	85.39	—	—	—
		ACNR	6.81	25.99	1.07	18.6%	69.6%
		Proposed	5.93	27.07	0.19	3.7%	68.3%
	Iodine	Original	−934.50	34.77	—	—	—
		ACNR	−935.87	9.26	1.37	0.2%	73.2%
		Proposed	−935.61	9.91	1.11	0.2%	71.5%
Case 4	Water	Original	9.42	45.94	—	—	—
		ACNR	7.48	15.89	1.94	20.6%	65.4%
		Proposed	8.70	16.57	0.72	7.6%	63.9%
	Iodine	Original	−993.72	12.84	—	—	—
		ACNR	−994.56	3.41	0.84	0.08%	73.4%
		Proposed	−994.25	3.94	0.53	0.05%	69.3%
Case 5	Water	Original	12.98	161.68	—	—	—
		ACNR	15.81	48.47	2.83	21.8%	70.0%
		Proposed	13.85	51.20	0.87	6.7%	68.3%
	Iodine	Original	−990.19	20.36	—	—	—
		ACNR	−989.32	6.25	0.87	0.09%	69.3%
		Proposed	−988.89	6.76	1.3	0.1%	66.8%
		Original	—	—	—	—	—
Average		ACNR	—	—	2.18	13.1%	69.3%
		Proposed	—	—	0.69	2.40%	66.5%
		Original	—	—	—	—	—
Maximum		ACNR	—	—	8.97	58.7%	73.4%
		Proposed	—	—	1.31	7.6%	71.5%