title: Motion artifacts in kidney stone imaging using single-source and dual-source dual-energy CT scanners: a phantom study.
abstract: OBJECTIVE
  Dual-energy computed tomography (DECT) has shown the capability of differentiating uric acid (UA) from non-UA stones with 90-100% accuracy. With the invention of dual-source (DS) scanners, both low- and high-energy images are acquired simultaneously. However, DECT can also be performed by sequential acquisition of both images on single-source (SS) scanners. The objective of this study is to investigate the effects of motion artifacts on stone classification using both SS-DECT and DS-DECT.
  
  
  METHODS
  114 kidney stones of different types and sizes were imaged on both DS-DECT and SS-DECT scanners with tube voltages of 80 and 140 kVp with and without induced motion. Postprocessing was conducted to create material-specific images from corresponding low- and high-energy images. The dual-energy ratio (DER) and stone material were determined and compared among different scans.
  
  
  RESULTS
  For the motionless scans, all stones were correctly classified with SS-DECT, while two cystine stones were misclassified with DS-DECT. When motion was induced, 94% of the stones were misclassified with SS-DECT versus 11% with DS-DECT (P < 0.0001). Stone size was not a factor in stone misclassification under motion. Stone type was not a factor in stone misclassification under motion with SS-DECT, although with DS-DECT, cystine showed higher number of stone misclassification.
  
  
  CONCLUSIONS
  Motion artifacts could result in stone misclassification in DECT. This effect is more pronounced in SS-DECT versus DS-DECT, especially if stones of different types lie in close proximity to each other. Further, possible misinterpretation of the number of stones (i.e., missing one, or thinking that there are two) in DS-DECT could be a potentially significant problem.
authors: Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA. elsayei@umich.edu.|University of Michigan, 1500 E. Medical Center Dr., Ann Arbor, MI, 48109, USA. elsayei@umich.edu.
authors: El-Sayed H
authors: el-SH
authors: Ibrahim
authors: Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA.
authors: Joseph G
authors: JG
authors: Cernigliaro
authors: Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA.
authors: Robert A
authors: RA
authors: Pooley
authors: Indiana University, 340 W 10th St, Indianapolis, IN, 46202, USA.
authors: James C
authors: JC
authors: Williams
authors: Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL, 32224, USA.
authors: William E
authors: WE
authors: Haley
mesh_terms: D016477:Artifacts; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D009038:Motion; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*
keywords: Dual-energy computed tomography; Kidney stones; Motion artifacts; Nephrolithiasis