title: CT angiography in potential living kidney donors: 80 kVp versus 120 kVp.
abstract: OBJECTIVE
  The purpose of this article is to retrospectively investigate the diagnostic accuracy, image quality, and radiation dose of renal artery CT angiography (CTA), at 80 kVp compared with 120 kVp, in adult kidney donors.
  
  
  METHODS
  CTA examinations of 258 consecutive potential kidney donors were retrospectively evaluated; 189 patients were scanned using 64-MDCT scanners (higher maximal tube current), and 69 patients were scanned using 16-MDCT scanners (lower maximal tube current). On the basis of the tube potential and scanners, the study population was divided into four groups. Qualitative and quantitative analysis include vascular attenuation measurements, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Volume CT dose index (CTDIvol) was recorded, and size-specific dose estimate was also estimated.
  
  
  RESULTS
  Using 80 kVp for the 16-MDCT scanner, there was a 64.9% reduction in size-specific dose estimate (66.1% reduction in CTDIvol), increased noise, and tube current saturation in all cases. Axial image quality was significantly lower compared with that obtained at 120 kVp (p = 0.02), but image quality and visibility of renal artery branch order were comparable. Using 80 kVp for the 64-MDCT scanner, there was a 40.5% reduction in size-specific dose estimate (43.6% reduction in CTDIvol) and increased SNR and CNR (p < 0.001). No significant differences in 3D image quality and branch order visibility were observed. Tube current saturation was reached in 31% of cases. One hundred fifty-one patients (86 imaged at 80 kVp and 65 imaged at 120 kVp) underwent donor nephrectomy; CTA diagnostic accuracy was 100%.
  
  
  CONCLUSIONS
  Renal artery CTA using 80 kVp combined with limiting the tube current results in a significant reduction in radiation dose and improved SNR and CNR, without deterioration of image quality.
authors.affiliation: 1 Department of Radiology, Yale School of Medicine, 20 York St, New Haven, CT 06510.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Davarpanah
authors.forename: Jay K
authors.initials: JK
authors.lastname: Pahade
authors.forename: Dan
authors.initials: D
authors.lastname: Cornfeld
authors.forename: Monica
authors.initials: M
authors.lastname: Ghita
authors.forename: Sanjay
authors.initials: S
authors.lastname: Kulkarni
authors.forename: Gary M
authors.initials: GM
authors.lastname: Israel
mesh_terms: D000328:Adult; D000792:Angiography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007472:Iohexol; D016030:Kidney Transplantation; D019520:Living Donors; D008297:Male; D011829:Radiation Dosage; D012077:Renal Artery / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol