Brief Article
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World J Radiol. Mar 28, 2012; 4(3): 97-101
Published online Mar 28, 2012. doi: 10.4329/wjr.v4.i3.97
Prediction of transitional lumbosacral anatomy on magnetic resonance imaging of the lumbar spine
Majid Chalian, Theodoros Soldatos, John A Carrino, Alan J Belzberg, Jay Khanna, Avneesh Chhabra
Majid Chalian, Theodoros Soldatos, John A Carrino, Avneesh Chhabra, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Hospital, Baltimore, MD 21287, United States
Alan J Belzberg, Department of Neurosurgery, The Johns Hopkins Hospital, Baltimore, MD 21287, United States
Jay Khanna, Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD 21287, United States
Author contributions: All authors contributed equally to the design and execution of the study, analysis of the data and writing of the paper.
Correspondence to: Avneesh Chhabra, MD, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Hospital, 601 North Caroline Street, Baltimore, MD 21287, United States. achhabr6@jhmi.edu
Telephone: +1-443-2876032 Fax: +1-443-2876438
Received: August 18, 2011
Revised: February 22, 2012
Accepted: March 1, 2012
Published online: March 28, 2012
Abstract

AIM: To evaluate two simple angle measurements for predicting lumbosacral transitional vertebra (LSTV) in magnetic resonance imaging (MRI) studies of the spine.

METHODS: The lumbar spine MRI studies of 50 subjects with LSTV and 50 subjects with normal lumbosacral anatomy were retrospectively evaluated. In each study, the mid-sagittal T2-weighted image was used to measure the angle formed by a line parallel to the superior surface of the sacrum and a line perpendicular to the axis of the scan table (A-angle), as well as the angle formed by a line parallel to the superior endplate of the L3 vertebra and a line parallel to the superior surface of the sacrum (B-angle).

RESULTS: The total study population consisted of 100 subjects (46 males, 54 females, 51 ± 16 years old). There were no differences in age and sex between the two groups. Both A-angle and B-angle were significantly increased in subjects with LSTV compared to controls (P < 0.05). The optimal cut-off values of A-angle and B-angle for the prediction of LSTV were 39.8° (sensitivity = 80%, specificity = 80%, accuracy = 83%; 95% confidence interval = 74%-89%, P = 0.0001) and 35.9° (sensitivity = 80%, specificity = 54%, accuracy = 69%; 95% confidence interval = 59%-78%, P = 0.0005), respectively.

CONCLUSION: On sagittal MR images of the lumbar spine, an increased A-angle and/or B-angle should alert the radiologist to the presence of LSTV.

Keywords: Lumbosacral transitional vertebra, Magnetic resonance imaging, Lumbar spine, Angle, Prediction