Low-dose computed tomography with 4th-generation iterative reconstruction algorithm in assessment of oncologic patients

Table 1 Descriptive table of weight groups in the patients population (n = 51)

Weight groups	No. of patients	M/F	Mean ± SD (yr)
Group A (41-60 kg)	8	3/5	70.5 ± 8.6
Group B (61-80 kg)	25	9/16	67.6 ± 11.5
Group C (81-90 kg)	13	11/2	71.8 ± 7.4
Group D ( > 90 kg)	5	4/1	59.2 ± 10.1
All patients	51	34/18	68.3 ± 10.4

M: Male; F: Female.

Table 2 Comparison of Dose-Length Product and Volumetric Computed Tomographic Dose Index obtained with standard-dose and low-dose protocols in all patients (n = 51) and according to weight (kg)

BMI groups	No. of patients	CTDIvol (mGy)			DLP (mGy*cm)			% DLP reduction
		Standard-dose	Low-dose	P-value	Standard-dose	Low-dose	P-value
Group A (41-60 kg)	8	14.1 ± 0.0	9.8 ± 1.5	0.012	891.9 ± 36.3	627.5 ± 92.9	0.012	29.6
Group B (61-80 kg)	25	21.1 ± 0.0	14.0 ± 2.8	< 0.001	1386.6 ± 65.9	920.0 ± 175.0	< 0.001	33.5
Group C (81-90 kg)	13	24.6 ± 0.0	17.2 ± 2.9	0.001	1656.8 ± 61.2	1162.6 ± 204.2	0.001	29.9
Group D ( > 90 kg)	5	27.4 ± 1.5	26.5 ± 5.4	0.5	1910.4 ± 147.6	1835.1 ± 359.5	0.5	2.5
All patients	51	21.4 ± 4.0	15.4 ± 5.2	< 0.001	1429.2 ± 297.7	1025.6 ± 370.9	< 0.001	28.9

DLP: Dose-Length-Product; CTDIvol: Volumetric Computed Tomographic Dose Index.

Table 3 Qualitative scoring of image noise, image sharpness and diagnostic quality of computed tomography images from Reader 1 and Reader 2

	Image noise		Image sharpness		Diagnostic quality
	Reader 1	Reader 2	Reader 1	Reader 2	Reader 1	Reader 2
Low-dosea	3.4 ± 0.6	3.6 ± 0.6	3.7 ± 0.5	3.7 ± 0.5	3.7 ± 0.5	3.8 ± 0.4
Group A (n = 8)	3.6 ± 0.7	3.8 ± 0.5	3.6 ± 0.5	3.5 ± 0.5	3.9 ± 0.4	3.8 ± 0.5
Group B (n = 25)	3.4 ± 0.6	3.6 ± 0.6	3.8 ± 0.5	3.8 ± 0.4	3.7 ± 0.6	3.8 ± 0.4
Group C (n = 13)	3.1 ± 0.4	3.6 ± 0.5	3.6 ± 0.5	3.9 ± 0.4	3.6 ± 0.5	4.0 ± 0.0
Group D (n = 5)	3.3 ± 0.6	3.0 ± 1.0	4.0 ± 0.0	3.3 ± 0.6	4.0 ± 0.0	3.7 ± 0.6
Standard-doseb	3.6 ± 0.7	3.5 ± 0.6	3.3 ± 0.7	3.5 ± 0.6	3.7 ± 0.5	3.8 ± 0.4
Group A (n = 8)	3.9 ± 0.4	3.5 ± 0.5	3.1 ± 0.6	3.4 ± 0.5	3.9 ± 0.4	3.8 ± 0.5
Group B (n = 25)	3.7 ± 0.5	3.7 ± 0.5	3.5 ± 0.6	3.5 ± 0.6	3.8 ± 0.4	3.8 ± 0.4
Group C (n = 13)	3.3 ± 0.5	3.3 ± 0.5	2.9 ± 0.7	3.9 ± 0.4	3.6 ± 0.5	4.0 ± 0.0
Group D (n = 5)	2.3 ± 1.5	3.0 ± 1.0	3.0 ± 1.0	3.3 ± 0.6	2.7 ± 1.2	3.7 ± 0.6
P-valuea-b	0.292	0.655	0.012	0.088	0.437	0.206
k Cohen Reader 1-Reader 2	0.694a-0.756b		0.783a-0.672b		0.704a-0.786b

Table 4 Computed tomography values (HU), standard deviation of computed tomography values (SD) and signal-to-noise ratio obtained with standard-dose and low-dose protocols

	Low-dose	Standard-dose	P-value
HUaorta (n = 51)	166.20 ± 18.83	154.17 ± 24.82	< 0.001
HUliver (n = 51)	112.55 ± 16.49	103.90 ± 17.49	< 0.001
HUspleen (n = 51)	126.24 ± 13.60	112.77 ± 15.66	< 0.001
SDliver (n = 51)	16.81 ± 2.02	14.41 ± 3.33	< 0.001
SDspleen (n = 51)	16.78 ± 2.04	14.72 ± 3.26	< 0.001
SDfat (n = 51)	12.17 ± 2.77	12.07 ± 2.98	0.307
SNRliver (n = 51)	6.94 ± 1.32	7.80 ± 2.30	0.002
SNRliver Group A (n = 8)	8.09 ± 1.63	9.36 ± 2.27	0.05
SNRliver Group B (n = 25)	6.95 ± 1.22	8.53 ± 1.97	< 0.001
SNRliver Group C (n = 13)	6.47 ± 1.00	6.66 ± 1.34	0.972
SNRliver Group D (n = 5)	6.29 ± 1.19	4.60 ± 1.77	0.08
SNRspleen (n = 51)	7.73 ± 1.46	8.10 ± 2.04	0.153
SNRspleen Group A (n = 8)	9.25 ± 2.31	10.53 ± 1.69	0.092
SNRspleen Group B (n = 25)	7.60 ± 1.10	8.04 ± 1.86	0.177
SNRspleen Group C (n = 13)	7.26 ± 1.11	7.20 ± 1.45	0.65
SNRspleen Group D (n = 5)	7.21 ± 0.82	6.86 ± 1.89	0.893

SNR: Signal-to-noise ratio.