title: The evaluation and comparison of kidney length obtained from axial cuts in spiral CT scan with its true length.
abstract: BACKGROUND
  Increased size of kidney is the main symptom of pyelonephritis and renal ischemia in children. Ultrasound and computed tomography (CT) scan methods are the imaging methods for evaluating the urogenital system. The aim of this study is to compare the kidney length obtained from spiral CT scan with the true length obtained from multi-slice CT.
  
  
  METHODS
  From 100 patients 200 kidneys were examined in Alzahra Hospital in 2012. Multi-slice CT was used to obtain coronal and sagittal cuts to find the length of kidneys.
  
  
  RESULTS
  The mean values of true size of axial sections of the right and left kidneys were 108.37 ± 12.3 mm and 109.74 ± 13.6 mm, respectively. The mean difference of axial sections' lengths in the right and left kidneys was 1.37 ± 1.22 mm. The mean values of length in the spiral CT scan of the right and left kidneys were 98.61 ± 15.8 mm and 103.11 ± 15.9 mm, respectively. The difference in the estimated size by multi-slice CT scan in oblique and axial images was significant (9.77 ± 1.19 mm and 6.63 ± 0.8 mm for the right and left kidneys, respectively (P < 0.001).
  
  
  CONCLUSIONS
  The average size of both kidneys determined in axial images was smaller than the actual size. The estimation of kidney size in axial images is not reliable, and to obtain the actual size, it is required to have the coronal and sagittal cuts with proper quality, which could be achieved by multi-slice method.
authors.affiliation: Department of Radiology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Karami
authors.affiliation: General Physician, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Farshad
authors.initials: F
authors.lastname: Rahimi
authors.affiliation: Applied Physiology research center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohammadhasan
authors.initials: M
authors.lastname: Tajadini
keywords: Computed tomography scan; kidney; renal length