Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner.
OBJECTIVE
The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners.


METHODS
This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner.


RESULTS
The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures.


CONCLUSIONS
Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners.
Division of Cancer Screening, National Cancer Center, Research Center for Cancer Prevention and Screening, Chuo-ku, Tokyo, Japan; Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Ryutaro
R
Kakinuma
Division of Cancer Screening, National Cancer Center, Research Center for Cancer Prevention and Screening, Chuo-ku, Tokyo, Japan.
Noriyuki
N
Moriyama
Division of Cancer Screening, National Cancer Center, Research Center for Cancer Prevention and Screening, Chuo-ku, Tokyo, Japan.
Yukio
Y
Muramatsu
Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Shiho
S
Gomi
Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Masahiro
M
Suzuki
Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Hirobumi
H
Nagasawa
Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan; Department of Radiology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
Masahiko
M
Kusumoto
Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Tomohiko
T
Aso
Department of Radiology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
Yoshihisa
Y
Muramatsu
Department of Endoscopy, Respiratory Endoscopy Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Takaaki
T
Tsuchida
Division of Pathology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Koji
K
Tsuta
Division of Pathology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Akiko Miyagi
AM
Maeshima
Division of Pathology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Naobumi
N
Tochigi
Department of Thoracic Surgery, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Shun-Ichi
S
Watanabe
Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
Naoki
N
Sugihara
Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
Shinsuke
S
Tsukagoshi
Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
Yasuo
Y
Saito
Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
Masahiro
M
Kazama
Department of Clinical Oncology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Nagasaki, Japan.
Kazuto
K
Ashizawa
Department of Diagnostic Radiology, Hiroshima University, Institute and Graduate School of Biomedical Sciences, Hiroshima, Hiroshima, Japan.
Kazuo
K
Awai
Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Osamu
O
Honda
Department of Radiology, Niigata University Medical and Dental Hospital, Niigata, Niigata, Japan.
Hiroyuki
H
Ishikawa
Department of Radiology, Niigata Cancer Center Hospital, Niigata, Niigata, Japan.
Naoya
N
Koizumi
Department of Diagnostic Radiology, Hiroshima University, Institute and Graduate School of Biomedical Sciences, Hiroshima, Hiroshima, Japan.
Daisuke
D
Komoto
Department of Radiology, Ohara General Hospital, Fukushima, Fukushima, Japan.
Hiroshi
H
Moriya
Department of Diagnostic Radiology, Kumamoto University, Faculty of Life Sciences, Kumamoto, Kumamoto, Japan.
Seitaro
S
Oda
Department of Radiology, National Hospital Organization Okinawa National Hospital, Ginowan, Okinawa, Japan.
Yasuji
Y
Oshiro
Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Masahiro
M
Yanagawa
Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Noriyuki
N
Tomiyama
Department of Thoracic Surgery, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.
Hisao
H
Asamura
D000230:Adenocarcinoma / Q000000981:diagnostic imaging; D000077192:Adenocarcinoma of Lung; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D015588:Observer Variation; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*