Radiation dose reduction with dictionary learning based processing for head CT.

Yang Chen (1, 2, 3) , Luyao Shi (1, 2, 3) , Jiang Yang (4) , Yining Hu (1, 2, 3) , Limin Luo (1, 2, 3) , Xindao Yin (5) , Jean-Louis Coatrieux (1, 6)

1 CRIBS - Centre de Recherche en Information Biomédicale sino-français
2 LIST - Laboratory of Image Science and Technology [Nanjing]
3 Key Laboratory of Computer Network and Information Integration
4 Key Laboratory of Photoelectronic Imaging Technology and System
5 Department of Radiology
6 LTSI - Laboratoire Traitement du Signal et de l'Image

: In CT, ionizing radiation exposure from the scan has attracted much concern from patients and doctors. This work is aimed at improving head CT images from low-dose scans by using a fast Dictionary learning (DL) based post-processing. Both Low-dose CT (LDCT) and Standard-dose CT (SDCT) nonenhanced head images were acquired in head examination from a multi-detector row Siemens Somatom Sensation 16 CT scanner. One hundred patients were involved in the experiments. Two groups of LDCT images were acquired with 50 % (LDCT50 %) and 25 % (LDCT25 %) tube current setting in SDCT. To give quantitative evaluation, Signal to noise ratio (SNR) and Contrast to noise ratio (CNR) were computed from the Hounsfield unit (HU) measurements of GM, WM and CSF tissues. A blinded qualitative analysis was also performed to assess the processed LDCT datasets. Fifty and seventy five percent dose reductions are obtained for the two LDCT groups (LDCT50 %, 1.15 ± 0.1 mSv; LDCT25 %, 0.58 ± 0.1 mSv; SDCT, 2.32 ± 0.1 mSv; P < 0.001). Significant SNR increase over the original LDCT images is observed in the processed LDCT images for all the GM, WM and CSF tissues. Significant GM-WM CNR enhancement is noted in the DL processed LDCT images. Higher SNR and CNR than the reference SDCT images can even be achieved in the processed LDCT50 % and LDCT25 % images. Blinded qualitative review validates the perceptual improvements brought by the proposed approach. Compared to the original LDCT images, the application of DL processing in head CT is associated with a significant improvement of image quality.

Domaines: Ingénierie biomédicale

Yang Chen, Luyao Shi, Jiang Yang, Yining Hu, Limin Luo, et al.. Radiation dose reduction with dictionary learning based processing for head CT.. Australasian Physical and Engineering Sciences in Medicine, 2014, 37 ((3)), pp.483-93. ⟨10.1007/s13246-014-0276-7⟩. ⟨inserm-01007561⟩