J Korean Soc Radiol.  2018 Jan;78(1):35-43. 10.3348/jksr.2018.78.1.35.

Attenuation-Based Automatic Tube Potential Selection in Cerebral Computed Tomography Angiography: Effects on Radiation Exposure and Image Quality

• Choi JM
• Kim JH
• Kang SM
• Yu JS
• Chung JJ
• Cho ES

• KMID: 2399304
• DOI: http://doi.org/10.3348/jksr.2018.78.1.35

Abstract

OBJECTIVE
To investigate the feasibility of using the attenuation-based automatic tube potential selection (ATPS) algorithm for cerebral computed tomography angiography (CTA) and to assess radiation dose, vascular attenuation, and image quality compared to a conventional fixed 120-kVp protocol.
MATERIALS AND METHODS
Among 36 volunteers for cerebral CTA, a total of 18 were scanned with fixed 120 kVp and 140 effective mAs using automatic tube current modulation. The other 18 were scanned with an ATPS algorithm. Radiation doses, attenuation, contrast-to-noise ratio (CNR) of the cerebral arteries, subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, venous contamination, image noise, and overall image quality were compared between the groups.
RESULTS
The volume CT dose index and effective dose of the ATPS group were lower than those of the fixed 120-kVp group. The ATPS group had significantly higher arterial attenuation and no significant difference in CNR, compared with the fixed 120-kVp. The ATPS group had higher subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, and overall image quality.
CONCLUSION
The ATPS algorithm for the cerebral CTA reduced radiation dose by 43% while maintaining image quality and improved the attenuation of cerebral arteries by selecting lower tube potential.

MeSH Terms

Adenosine Triphosphate
Angiography*
Arteries
Brain
Cerebral Arteries
Cone-Beam Computed Tomography
Noise
Radiation Exposure*
Volunteers
Adenosine Triphosphate

Figure

• 

  Fig. 1. Cerebral CTA of 38-year-old woman, using the fixed 120-kVp protocol. Axial (A) and coronal (B) maximum intensity projection images with a slab thickness of 10 mm and volume rendering image (C) were assessed. The mean attenuation value of the cerebral arteries (397.5 HU) and CNR (25.5) in this volunteer were similar to the mean attenuation value (377.3 HU) and mean CNR (24.7) for cerebral CTA in group A. CNR = contrast-to-noise radio, CTA = computed tomography angiography, HU = Hounsfield units

• 

  Fig. 2. Cerebral CTA of 50-year-old man, using the automatic tube potential selection protocol. Axial (A) and coronal (B) maximum intensity projection images with a slab thickness of 10 mm and volume rendering image (C) were assessed. A tube potential of 80 kVp was selected. The mean attenuation value of the cerebral arteries (560.5 HU) and CNR (22.8) in this volunteer were similar to the mean attenuation value (587.7 HU) and mean CNR (24.2) for cerebral CTA in group B. CNR = contrast-to-noise radio, CTA = computed tomography angiography, HU = Hounsfield units

Reference

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