title: Using MRI to evaluate anatomic significance of aortic bifurcation, right renal artery, and conus medullaris when locating lumbar vertebral segments.
abstract: OBJECTIVE
  This study evaluated the anatomic significance and sites of aortic bifurcation, right renal artery, and conus medullaris when locating lumbar vertebral segments on MRI. SUBJECTS AND METHODS. The study group was composed of 210 patients who underwent MRI of the lumbosacral spine. The position of aortic bifurcation was evaluated using MRI. Midline and sagittal MRI were also assessed to identify the proximal portion of the right renal artery and the tip of the conus medullaris. These locations were recorded in relation to the upper or lower half of the adjacent vertebral body or the adjacent intervertebral disk space.
  
  
  RESULTS
  The most common site of aortic bifurcation was at the L4 vertebra (83%). In most patients two separated iliac arteries were apparent at the level of the L4-L5 disk space (93%), and the right renal artery was located between the lower half of the L1 vertebra and the upper half of the L2 vertebra (92%). The position of the conus medullaris was variably located, and the most frequent site was at the L1 vertebra (56%).
  
  
  CONCLUSIONS
  The aortic bifurcation, the right renal artery, and the combination of these structures can be reliable landmarks for determining the lumbar vertebral segments on MRI or CT. However, conus medullaris cannot be considered a good landmark because of its variable locations.
authors.affiliation: Department of Diagnostic Radiology, University of Konkuk, Chung-Ju Hospital, 620-5 Kyohyun-Dong, Chung-Ju City, Chung-Buk 380-704, South Korea. chlee86@kku.ac.kr
authors.forename: Chang Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Bo Kyoung
authors.initials: BK
authors.lastname: Seo
authors.forename: Young Chil
authors.initials: YC
authors.lastname: Choi
authors.forename: Hyun Joon
authors.initials: HJ
authors.lastname: Shin
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Park
authors.forename: Hae Jeong
authors.initials: HJ
authors.lastname: Jeon
authors.forename: Kyeong Ah
authors.initials: KA
authors.lastname: Kim
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Park
authors.forename: Baek Hyun
authors.initials: BH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001011:Aorta / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012077:Renal Artery / Q000033:anatomy & histology*; D013116:Spinal Cord / Q000033:anatomy & histology*