title: Effect of region of interest and slice thickness on vertebral bone mineral density measured by use of quantitative computed tomography in dogs.
abstract: OBJECTIVE
  To determine the effect of region of interest (ROI) setting and slice thickness on trabecular bone mineral density (BMD) measured with quantitative CT in dogs.
  
  
  METHODS
  14 healthy Beagles.
  
  
  METHODS
  CT of the lumbar vertebrae and a quantitative CT phantom was performed. The BMD of trabecular bone was measured from L1 to L7 in 2 ways in all dogs. First, sequential 9.6-mm-thick CT images were acquired and then CT images were reconstructed into transverse CT images with slice thicknesses of 2.4, 4.8, and 9.6 mm. The obtained images were analyzed by circular ROI and trace ROI methods. Second, lumbar vertebrae were scanned with the installed quantitative CT protocol with a slice thickness of 10 mm and then the CT images were analyzed by installed automatic BMD software.
  
  
  RESULTS
  Interclass correlation coefficients of the automatic software (0.975 to 1.0) and the circular method (0.871 to 0.996) were high, compared with those of the trace method (0.582 to 0.996). The BMD measured with the automatic software was not significantly different from that measured with circular ROI and a slice thickness of 9.6 mm. The BMD measured by use of the circular method was not different according to slice thickness.
  
  
  CONCLUSIONS
  Results obtained by use of automatic software were similar to those obtained by use of more manual methods. The CT images with thinner slice thickness (2.4 and 4.8 mm) could be used in dogs of toy and small breeds to measure lumbar vertebrae BMD to reduce the limitations of the standard 10-mm slice thickness.
authors: Department of Veterinary Medical Imaging, College of Veterinary Medicine, Chonnam National University, Gwangju, 500-757, South Korea.
authors: Yeonho
authors: Y
authors: Bae
authors: Seungjo
authors: S
authors: Park
authors: Sunghoon
authors: S
authors: Jeon
authors: Gahyun
authors: G
authors: Lee
authors: Jihye
authors: J
authors: Choi
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D005260:Female; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D019047:Phantoms, Imaging / Q000662:veterinary; D012984:Software; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*