title: High-resolution metal artifact reduction MR imaging of the lumbosacral plexus in patients with metallic implants.
abstract: OBJECTIVE
  To assess the quality and accuracy of metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) for the diagnosis of lumbosacral neuropathies in patients with metallic implants in the pelvis.
  
  
  METHODS
  Twenty-two subjects with lumbosacral neuropathy following pelvic instrumentation underwent 1.5-T MARS MRI including optimized axial intermediate-weighted and STIR turbo spin echo sequences extending from L5 to the ischial tuberosity. Two readers graded the visibility of the lumbosacral trunk, sciatic, femoral, lateral femoral cutaneous, and obturator nerves and the nerve signal intensity of nerve, architecture, caliber, course, continuity, and skeletal muscle denervation. Clinical examination and electrodiagnostic studies were used as the standard of reference. Descriptive, agreement, and diagnostic performance statistics were applied.
  
  
  RESULTS
  Lumbosacral plexus visibility on MARS MRI was good (4) or very good (3) in 92% of cases with 81% exact agreement and a Kendall's W coefficient of 0.811. The obturator nerve at the obturator foramen and the sciatic nerve posterior to the acetabulum had the lowest visibility, with good or very good ratings in only 61% and 77% of cases respectively. The reader agreement for nerve abnormalities on MARS MRI was excellent, ranging from 95.5 to 100%. MARS MRI achieved a sensitivity of 86%, specificity of 67%, positive predictive value of 95%, and negative predictive value of 40%, and accuracy of 83% for the detection of neuropathy.
  
  
  CONCLUSIONS
  MARS MRI yields high image quality and diagnostic accuracy for the assessment of lumbosacral neuropathies in patients with metallic implants of the pelvis and hips.
authors.affiliation: The Russell H. Morgan Department of Radiology & Radiological Science, The Johns Hopkins Medical Institutions, 600 North Wolfe Street, Baltimore, MD, 21287, USA. sahlawa1@jhmi.edu.
authors.forename: Shivani
authors.initials: S
authors.lastname: Ahlawat
authors.affiliation: Bond Business School, Bond University, Gold Coast, QLD, 4229, Australia.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Stern
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD, 21287, USA.
authors.forename: Allan J
authors.initials: AJ
authors.lastname: Belzberg
authors.affiliation: The Russell H. Morgan Department of Radiology & Radiological Science, The Johns Hopkins Medical Institutions, 600 North Wolfe Street, Baltimore, MD, 21287, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Fritz
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008160:Lumbosacral Plexus / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008670:Metals; D008875:Middle Aged; D010523:Peripheral Nervous System Diseases / Q000000981:diagnostic imaging*; D019736:Prostheses and Implants; D012680:Sensitivity and Specificity
chemical_list: D008670:Metals
keywords: Lumbosacral plexus; MR imaging; Metal artifact reduction; Peripheral neuropathy