title: CT volumetry of lumbar vertebral bodies in patients with hypoplasia L5 and bilateral spondylolysis and in normal controls.
abstract: BACKGROUND
  To examine the feasibility and results of calculating the volume of lumbar vertebral bodies in normal patients and patients with suspected hypoplasia of L5.
  
  
  METHODS
  Lumbar multi-detector CT was performed in 38 patients with bilateral spondylolysis and hypoplasia of L5 and in 38 normal patients. Lumbar vertebral body volume of L3, L4 and L5 was measured by CT volumetry with a semi-automated program, created with MeVisLab.
  
  
  RESULTS
  In the control group, the average vertebral body volume (in cubic centimeters) of L3 was 35.93 (±7.33), 36.34 (±7.13) for L4 and 34.63 (±6.88) for L5. In patients with suspected hypoplasia L5 the average body volume (in cubic centimeters) of L3 was 36.85 (±7.37), 36.90 (±6.99) for L4 and 33.14 (±6.57) for L5. The difference in mean vertebral body volume for L3, L4 and L5 between both groups was statistically not significant. However, there was a statistically significant difference of the ratio L5/L4 (P < 0.001) between both groups: the mean ratio L5/L4 in the control group was 95.3 ± 3.9%, the ratio for the hypoplastic L5 group was 89.9 ± 6.3%.
  
  
  CONCLUSIONS
  There was no significant difference in the vertebral body volume for L3, L4 and L5 between both groups due to inter-patient variability. However, the relation between the body volume of L5 and L4 is significantly different between both groups. The volume of the vertebral body of L5 proved to be on average 10.2% smaller than the volume of L4 in the group with hypoplasia L5 versus 4.7% in the control group.
authors.affiliation: Department of Radiology, UZ Leuven, Campus Gasthuisberg, Herestraat 49, 3000, Leuven, Belgium. guido.wilms@uz.kuleuven.ac.be
authors.forename: Guido E
authors.initials: GE
authors.lastname: Wilms
authors.forename: Endry
authors.initials: E
authors.lastname: Willems
authors.forename: Philippe
authors.initials: P
authors.lastname: Demaerel
authors.forename: Frederik
authors.initials: F
authors.lastname: De Keyzer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D016022:Case-Control Studies; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D012984:Software; D013169:Spondylolysis / Q000000981:diagnostic imaging*