MRI and Anatomical Determinants Affecting Neuroforaminal Stenosis Evaluation: A Descriptive Observational Study

Abstract

Sayed E Wahezi,1 Terence Hillery,2 Rene Przkora,3 Tim Lubenow,4 Tim Deer,5 Chong Kim,2 Dawood Sayed,6 Jonathan Krystal,7 Merritt Kinon,8 Kishan Sitapara,7 Kim Nguyen,7 Daniel Wong,7 Karen Sperling7 1Montefiore Multidisciplinary Pain Program, Montefiore Medical Center, Bronx, NY, USA; 2The MetroHealth System, Cleveland, OH, USA; 3Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA; 4Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA; 5Department of Anesthesiology, West Virginia University, Morgantown, WV, USA; 6The University of Kansas Health System, Kansas City, KS, USA; 7Montefiore Medical Center, Bronx, NY, USA; 8Department of Neurosurgery, USA Brain and Spine Institute, Westchester Medical Center Health Network, New York Medical College, Valhalla, NY, USACorrespondence: Sayed E Wahezi, Montefiore Health System, Montefiore Multidisciplinary Pain Program, 1250 Waters Place, Tower #2, Bronx, NY, 10461, USA, Tel [phone], Fax [phone], Email [email protected]: Neuroforaminal stenosis (NFS), a narrowing of the intervertebral foramen, is a cause of disability in the aging population. Formal magnetic resonance imaging (MRI) classification of NSF has been developed recently and contradictory findings have been reported. This study aims to assess whether in-plane, anatomically conformed two-dimensional (2D) views of the neuroforamen characterize NFS more accurately than traditional axial, coronal, and sagittal views in healthy individuals with and without simulated scoliosis.Patients and methods: This observational study was approved by the designated institutional review board at our academic tertiary care center. Four volunteers underwent lumbar spine MRI twice, once in the supine position and once with intentionally introduced hip tilt. The latter resulted in lumbar curvature mimicking positioning errors approximating degenerative lumbar scoliosis. Anatomically oriented cuts such as axial with endplate correction and coronally obliqued parasagittals, also called coronal obliques, were performed. Standard sagittal and axial views were also performed in both the supine and rotated groups.Results: Coronal oblique and anatomically oriented axial views demonstrated the highest correlation with true neuroforaminal caliber. Deviation from anatomical congruence resulted in false measurements of neuroforaminal size. The hip-tilt studies produced MR that were less favorable to characterization of the caliber of neuroforamina. Coronal sections demonstrated reliability only when performed at the mid-pedicular lines. Standard axial views were reliable only when taken at the upper one-third of the neuroforamen. Coronal oblique views demonstrated superiority when evaluating consecutive neuroforamen on one image compared to non-obliqued parasagittal slices.Conclusion: To minimize error in neuroforaminal analysis, imaging specialists should perform anatomically oriented cuts to conform to individual patient anatomy. When this cannot be performed due to a patient’s spine rotation or position, the MRI reader should view oblique, axial, and coronal images simultaneously and dynamically for proper foraminal characterization.Keywords: foraminal stenosis, lumbar vertebrae, magnetic resonance imaging, neural foramen, scoliosis

Keywords

• foraminal stenosis
• lumbar vertebrae
• magnetic resonance imaging
• neural foramen
• scoliosis