Image reconstruction using small-voxel size improves small lesion detection for positron emission tomography

Rep, Sebastijan; Tomse, Petra; Jensterle, Luka; Jarabek, Leon; Zaletel, Katja; Lezaic, Luka

Image reconstruction using small-voxel size improves small lesion detection for positron emission tomography

Radiology and Oncology

Volume 56 (2022): Issue 2 (June 2022)

By:

Sebastijan Rep, Petra Tomse, Luka Jensterle, Leon Jarabek, Katja Zaletel and Luka Lezaic

Open Access

|Apr 2022

Figures & Tables

NEMA body (A) and the Micro Hollow-Sphere phantom (C), filled in the sphere-to-background radioactivity ratio 2:1, 3:1, 4:1, 8:1, and reconstructed with 2 mm (top row) and 4 mm (bottom row) in-line pixel size. Axial CT images with phantom spheres diameter of NEMA body (B) and the Micro Hollow-Sphere phantom (D).

Measurements of contrast-to-noise ratio (CNR)max/mean (top row) and contrast recovery coefficient (CRC)max/mean (bottom row) in all NEMA body and the Micro Hollow-Sphere phantom spheres for all radioactivity concentration ratios with 2 mm and 4 mm in-line pixel size.

Graphically represented contrast recovery coefficient (CRC)max/mean and contrast-to-noise ratio (CNR)max/mean of the 2 mm and 4 mm in-line pixel sizes.

Contrast-to-noise ratio (CNR)max, CNRmean, of the four Micro Hollow Sphere phantom and the six NEMA body phantom spheres filled with sphere-to-background radioactivity concentration ratios of 2:1, 3:1, 4:1, 8:1 for both 2 mm and 4 mm voxel size reconstructions, including relative changes in %

	Micro Hollow Sphere phantom - sphere diameter (mm)					NEMA body phantom - sphere diameter (mm)
Ratio 8:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	12.53	34.82	71.23	134.50	104.68	157.51	159.30	162.70	152.06	148.02
4 mm max	N/A	25.58	44.71	84.76	84.32	151.31	181.45	169.86	167.41	161.28
% change		36	59	59	24	4	-12	-4	-9	-8
2 mm mean	11.99	24.84	55.10	75.80	55.69	76.75	89.86	100.92	108.16	115.50
4 mm mean	N/A	17.41	40.95	55.58	54.73	78.83	93.99	107.44	116.37	123.83
% change		43	35	36	2	-3	-4	-6	-7	-7
Ratio 4:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	N/A	6.33	20.19	41.57	31.20	59.06	68.97	65.49	66.91	67.42
4 mm max	N/A	N/A	17.13	37.28	30.46	57.33	80.41	77.47	76.63	71.95
% change			18	12	2	3	-14	-15	-13	-6
2 mm mean	N/A	5.73	16.51	24.55	17.42	29.96	34.68	38.24	43.13	48.28
4 mm mean	N/A	N/A	16.04	23.93	16.91	29.57	39.95	42.28	47.14	53.26
% change			3	3	3	1	-13	-10	-9	-9
Ratio 3:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	N/A	N/A	7.72	23.53	18.69	32.87	44.04	41.32	42.66	41.87
4 mm max	N/A	N/A	N/A	16.13	18.18	31.84	45.27	49.36	48.04	47.15
% change				46	3	3	-10	-8	-9	-9
2 mm mean	N/A	N/A	6.11	13.45	11.28	16.93	21.28	22.58	25.55	28.23
4 mm mean	N/A	N/A	N/A	10.66	11.01	16.91	23.39	25.56	28.58	31.47
% change				26	2	0	9	-9	-9	-9
Ratio 2:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	N/A	N/A	N/A	N/A	5.49	15.68	19.40	22.51	22.90	22.73
4 mm max	N/A	N/A	N/A	N/A	4.00	15.08	20.40	24.89	25.48	24.94
% change					37	4	-5	-10	-10	-9
2 mm mean	N/A	N/A	N/A	N/A	1.64	6.93	7.59	9.95	11.97	13.85
4 mm mean	N/A	N/A	N/A	N/A	1.37	6.54	8.44	11.18	13.32	15.18
% change					20	6	-10	-11	-10	-9

Median, minimum and maximum values of contrast-to-noise ratio (CNR)max and CNRmean over all spheres-to-background ratios for all spheres, smaller (≤ 13 mm) spheres and larger (≥ 17 mm) spheres_ The values are given for images reconstructed with 2 mm and 4 mm in-line pixel size

	Number of spheres	Median	Minimum	Maximum
CNR_max 2 mm	30	42.26	5.49	162.60
CNR_max4 mm	30	46.21	4.00	181.45
CNR_mean 2 mm	30	25.56	1.64	115.50
CNR_mean 4 mm	30	27.15	1.37	123.83
CNR_max 2 mm; ≤ 13 mm	14	33.84	5.49	157.51
CNR_max 4 mm; ≤ 13 mm	14	31.15	4.00	151.31
CNR_mean 2 mm; ≤ 13 mm	14	20.98	1.64	76.75
CNR_mean 4 mm; ≤ 13 mm	14	17.16	1.37	78.73
CNR_max 2 mm; ≥ 17 mm	16	54.76	19.40	162.70
CNR_max 4 mm; ≥ 17 mm	16	60.65	20.40	181.45
CNR_mean 2 mm; ≥ 17 mm	16	31.45	7.59	115.50
CNR_mean 4 mm; ≥ 17 mm	16	35.71	8.44	123.83

Median, minimum and maximum values of contrast recovery coefficient (CRC)max and CRCmean over all for all spheres, spheres ≤ 13 mm and spheres ≥ 17 mm_ The values are given for images reconstructed with 2 mm and 4 mm voxel size

	Number of spheres	Median	Minimum	Maximum
CRC_max 2 mm	30	0.88	0.16	0.98
CRC_max 4 mm	30	0.87	0.13	1.03
CRC_mean 2 mm	30	0.60	0.14	0.75
CRC_mean 4 mm	30	0.59	0.13	0.76
CRC_max 2 mm; ≤ 13 mm	14	0.56	0.16	0.92
CRC_max 4 mm; ≤ 13 mm	14	0.52	0.13	0.84
CRC_mean 2 mm; ≤ 13 mm	14	0.40	0.14	0.60
CRC_mean 4 mm; ≤ 13 mm	14	0.38	0.13	0.60
CRC_max 2 mm; ≥ 17 mm	16	0.94	0.87	0.98
CRC_max 4 mm; ≥ 17 mm	16	0.94	0.87	1.03
CRC_mean 2 mm; ≥ 17 mm	16	0.66	0.57	0.75
CRC_mean 4 mm; ≥ 17 mm	16	0.66	0.56	0.76

Contrast recovery coefficient (CRC)max, CRCmean, of the four Micro Hollow Sphere phantom and the six NEMA body phantom spheres filled with sphere-to-background radioactivity concentration ratios of 2:1, 3:1, 4:1, 8:1 for both 2 mm and 4 mm in-line pixel size reconstructions, including relative changes in %

Micro Hollow Sphere phantom - sphere diameter (mm)						NEMA body phantom - sphere diameter (mm)
Ratio 8:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	0.11	0.16	0.24	0.38	0.65	0.92	0.93	0.95	0.89	0.87
4 mm max	N/A	0.15	0.21	0.33	0.51	0.84	0.99	0.93	0.92	0.89
% change		2	14	17	26	10	-5	2	-2	-2
2 mm mean	0.10	0.14	0.20	0.25	0.39	0.50	0.57	0.63	0.67	0.71
4 mm mean	N/A	0.13	0.19	0.24	0.37	0.49	0.56	0.63	0.67	0.71
% change		4	2	3	6	3	2	0	0	0
Ratio 4:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	N/A	0.21	0.28	0.40	0.57	0.87	0.98	0.94	0.96	0.96
4 mm max	N/A	N/A	0.26	0.38	0.53	0.80	1.03	1.00	1.00	0.95
% change			6	5	8	9	-5	-6	-4	2
2 mm mean	N/A	0.20	0.26	0.30	0.41	0.55	0.60	0.64	0.70	0.75
4 mm mean	N/A	N/A	0.26	0.30	0.39	0.52	0.63	0.64	0.70	0.75
% change			0	0	5	6	-4	-1	0	-1
Ratio 3:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	N/A	N/A	0.28	0.38	0.57	0.78	0.94	0.90	0.92	0.91
4 mm max	N/A	N/A	N/A	0.36	0.53	0.71	0.89	0.94	0.93	0.91
% change				7	7	9	6	-1	0	0
2 mm mean	N/A	N/A	0.26	0.31	0.64	0.54	0.61	0.62	0.67	0.71
4 mm mean	N/A	N/A	N/A	0.31	0.43	0.51	0.60	0.63	0.67	0.71
% change				1	5	5	1	-1	0	0
Ratio 2:1	4 mm	5 mm	6 mm	8 mm	10 mm	13 mm	17 mm	22 mm	28 mm	37 mm
2 mm max	N/A	N/A	N/A	N/A	0.57	0.79	0.87	0.94	0.95	0.94
4 mm max	N/A	N/A	N/A	N/A	0.53	0.74	0.85	0.93	0.95	0.93
% change					8	6	3	0	0	1
2 mm mean	N/A	N/A	N/A	N/A	0.48	0.60	0.61	0.66	0.71	0.75
4 mm mean	N/A	N/A	N/A	N/A	0.47	0.58	0.61	0.67	0.71	0.74
% change					2	4	0	-1	0	1

DOI: https://doi.org/10.2478/raon-2022-0015 | Journal eISSN: 1581-3207 | Journal ISSN: 1318-2099

Journal RSS Feed

Language: English

Page range: 142 - 149

Submitted on: Feb 1, 2022

Accepted on: Feb 16, 2022

Published on: Apr 13, 2022

Published by: Association of Radiology and Oncology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 times per year

Keywords:

PET/CT,

voxel size,

contrast recovery coefficient,

contrast-to-noise ratio

Related subjects:

Medicine,

Clinical medicine,

Internal medicine,

Haematology, oncology,

Radiology

© 2022 Sebastijan Rep, Petra Tomse, Luka Jensterle, Leon Jarabek, Katja Zaletel, Luka Lezaic, published by Association of Radiology and Oncology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Previous article Volume 56 (2022): Issue 2 (June 2022)Next article

Image reconstruction using small-voxel size improves small lesion detection for positron emission tomography

Figures & Tables

Figure 1

Figure 2

Figure 3

Contrast-to-noise ratio (CNR)max, CNRmean, of the four Micro Hollow Sphere phantom and the six NEMA body phantom spheres filled with sphere-to-background radioactivity concentration ratios of 2:1, 3:1, 4:1, 8:1 for both 2 mm and 4 mm voxel size reconstructions, including relative changes in %

Median, minimum and maximum values of contrast-to-noise ratio (CNR)max and CNRmean over all spheres-to-background ratios for all spheres, smaller (≤ 13 mm) spheres and larger (≥ 17 mm) spheres_ The values are given for images reconstructed with 2 mm and 4 mm in-line pixel size

Median, minimum and maximum values of contrast recovery coefficient (CRC)max and CRCmean over all for all spheres, spheres ≤ 13 mm and spheres ≥ 17 mm_ The values are given for images reconstructed with 2 mm and 4 mm voxel size

Paradigm

My account