Knowledge-based iterative model reconstruction technique in computed tomography of lumbar spine lowers radiation dose and improves tissue differentiation for patients with lower back pain.
OBJECTIVE
To evaluate the image quality and diagnostic confidence of reduced-dose computed tomography (CT) of the lumbar spine (L-spine) reconstructed with knowledge-based iterative model reconstruction (IMR).


METHODS
Prospectively, group A consisted of 55 patients imaged with standard acquisition reconstructed with filtered back-projection. Group B consisted of 58 patients imaged with half tube current, reconstructed with hybrid iterative reconstruction (iDose(4)) in Group B1 and knowledge-based IMR in Group B2. Signal-to-noise ratio (SNR) of different regions, the contrast-to-noise ratio between the intervetebral disc (IVD) and dural sac (D-D CNR), and subjective image quality of different regions were compared. Higher strength IMR was also compared in spinal stenosis cases.


RESULTS
The SNR of the psoas muscle and D-D CNR were significantly higher in the IMR group. Except for the facet joint, subjective image quality of other regions including IVD, intervertebral foramen (IVF), dural sac, peridural fat, ligmentum flavum, and overall diagnostic acceptability were best for the IMR group. Diagnostic confidence of narrowing IVF and IVD was good (kappa=0.58-0.85). Higher strength IMR delineated IVD better in spinal stenosis cases.


CONCLUSIONS
Lower dose CT of L-spine reconstructed with IMR demonstrates better tissue differentiation than iDose(4) and standard dose CT with FBP.
Department of Medical Imaging, Pojen General Hopsital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Cheng Hui
CH
Yang
Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.
Tung-Hsin
TH
Wu
School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan. Electronic address: bcjlin@me.com.
Chung-Jung
CJ
Lin
School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
Yi-You
YY
Chiou
School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
Ying-Chou
YC
Chen
School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
Ming-Huei
MH
Sheu
School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
Wan-Yuo
WY
Guo
School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
Chen Fen
CF
Chiu
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D017116:Low Back Pain / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D018579:Patient Selection; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013122:Spinal Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods
Computer tomography; Diagnostic confidence; Image quality; Iterative reconstruction; Lumbar spine; Radiation dose