Subjective and objective comparisons of image quality between ultra-high-resolution CT and conventional area detector CT in phantoms and cadaveric human lungs

Masahiro Yanagawa; Akinori Hata; Osamu Honda; Noriko Kikuchi; Tomo Miyata; Ayumi Uranishi; Shinsuke Tsukagoshi; Noriyuki Tomiyama

doi:10.1007/s00330-018-5491-2

Subjective and objective comparisons of image quality between ultra-high-resolution CT and conventional area detector CT in phantoms and cadaveric human lungs

Eur Radiol. 2018 Dec;28(12):5060-5068. doi: 10.1007/s00330-018-5491-2. Epub 2018 May 29.

Authors

Masahiro Yanagawa¹, Akinori Hata², Osamu Honda², Noriko Kikuchi², Tomo Miyata², Ayumi Uranishi³, Shinsuke Tsukagoshi³, Noriyuki Tomiyama²

Affiliations

¹ Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka, 565-0871, Japan. m-yanagawa@radiol.med.osaka-u.ac.jp.
² Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka, 565-0871, Japan.
³ Department of CT Systems, Canon Medical Systems Corp., Otawara, Tochigi, Japan.

Abstract

Objectives: To compare the image quality of the lungs between ultra-high-resolution CT (U-HRCT) and conventional area detector CT (AD-CT) images.

Methods: Image data of slit phantoms (0.35, 0.30, and 0.15 mm) and 11 cadaveric human lungs were acquired by both U-HRCT and AD-CT devices. U-HRCT images were obtained with three acquisition modes: normal mode (U-HRCT_N: 896 channels, 0.5 mm × 80 rows; 512 matrix), super-high-resolution mode (U-HRCT_SHR: 1792 channels, 0.25 mm × 160 rows; 1024 matrix), and volume mode (U-HRCT_SHR-VOL: non-helical acquisition with U-HRCT_SHR). AD-CT images were obtained with the same conditions as U-HRCT_N. Three independent observers scored normal anatomical structures (vessels and bronchi), abnormal CT findings (faint nodules, solid nodules, ground-glass opacity, consolidation, emphysema, interlobular septal thickening, intralobular reticular opacities, bronchovascular bundle thickening, bronchiectasis, and honeycombing), noise, artifacts, and overall image quality on a 3-point scale (1 = worst, 2 = equal, 3 = best) compared with U-HRCT_N. Noise values were calculated quantitatively.

Results: U-HRCT could depict a 0.15-mm slit. Both U-HRCT_SHR and U-HRCT_SHR-VOL significantly improved visualization of normal anatomical structures and abnormal CT findings, except for intralobular reticular opacities and reduced artifacts, compared with AD-CT (p < 0.014). Visually, U-HRCT_SHR-VOL has less noise than U-HRCT_SHR and AD-CT (p < 0.00001). Quantitative noise values were significantly higher in the following order: U-HRCT_SHR (mean, 30.41), U-HRCT_SHR-VOL (26.84), AD-CT (16.03), and U-HRCT_N (15.14) (p < 0.0001). U-HRCT_SHR and U-HRCT_SHR-VOL resulted in significantly higher overall image quality than AD-CT and were almost equal to U-HRCT_N (p < 0.0001).

Conclusions: Both U-HRCT_SHR and U-HRCT_SHR-VOL can provide higher image quality than AD-CT, while U-HRCT_SHR-VOL was less noisy than U-HRCT_SHR.

Key points: • Ultra-high-resolution CT (U-HRCT) can improve spatial resolution. • U-HRCT can reduce streak and dark band artifacts. • U-HRCT can provide higher image quality than conventional area detector CT. • In U-HRCT, the volume mode is less noisy than the super-high-resolution mode. • U-HRCT may provide more detailed information about the lung anatomy and pathology.

Keywords: Artifacts; Diagnostic imaging; Image enhancement; Lung diseases; Multidetector computed tomography.

Publication types

Comparative Study

MeSH terms

Artifacts
Bronchiectasis / diagnostic imaging
Cadaver
Humans
Lung / diagnostic imaging*
Lung Diseases / diagnostic imaging*
Phantoms, Imaging
Pulmonary Emphysema / diagnostic imaging
Tomography, X-Ray Computed / instrumentation
Tomography, X-Ray Computed / methods*