Document Detail


Minimizing ferromagnetic artefact with metallic lumbar total disc arthroplasty devices at adjacent segments: technical note.
MedLine Citation:
PMID:  20081522     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY DESIGN: Technical report. OBJECTIVE: To minimize the gross artefact associated with a conventional metallic lumbar total disc arthroplasty (TDA) device on a conventional high field-strength (1.5 Tesla [T]) magnetic resonance imaging (MRI) scanner. SUMMARY OF BACKGROUND DATA: Gross artefact is often apparent with ferromagnetic metallic TDA devices on conventional high field-strength MRI scanners. Such artefact completely obliterates MRI assessment at the operated level, and usually obscures visualization of adjacent segments. Because adjacent segment preservation is a raison d'?tre of spinal TDA, clarity of imaging at this latter level is imperative. A failure to image adjacent segments may presage investigations, which are either invasive (e.g., myelography) or associated with significant radiation hazard (e.g., computed tomography), both with significantly less diagnostic sensitivity. This could negatively direct TDA choice with certain TDAs. METHODS: Progressive modifications to specific imaging parameter settings were sought on a conventional high field-strength (1.5T) closed-bore scanner to match the minimal artefact previously observed on a lower field-strength (0.3T) open scanner. Direct comparisons were made between each modified protocol image obtained initially using a phantom; however, routine postoperative MRIs were subsequently obtained in n = 40 patients following lumbar TDA insertion. RESULTS: Key parameter modifications were required in the receive bandwidth, the strength of the frequency encoding gradient, as well as in the echo train length. The use of higher specification "focused gradients" was also avoided. The overall effect was to reduce the slew rate of the gradients, which limited artefact due to a decrease in phase dispersion. Such appearances effectively matched with those previously obtained on the low field-strength (0.3T) open scanner in n = 40 patients. CONCLUSION: Relatively simple modifications to MRI parameter settings can be made on conventional high field-strength (1.5T) closed-bore scanners, which minimize metal artefact and enhance imaging of adjacent segments with ferromagnetic TDA devices. Such modifications effectively match appearances to those obtained with outmoded low field-strength (0.3T) open-bore scanners.
Authors:
Laurence A G Marshman; Graeme Strong; Matthew Trewhella; Ata Kasis; Tai Friesem
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Spine     Volume:  35     ISSN:  1528-1159     ISO Abbreviation:  Spine     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2010-01-18     Completed Date:  2010-03-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7610646     Medline TA:  Spine (Phila Pa 1976)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  252-6     Citation Subset:  IM    
Affiliation:
Department of Spinal Surgery, University Hospital of North Tees, Hardwick, Stockton. l.a.g.marshman@btinternet.com
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Arthroplasty, Replacement / instrumentation
Artifacts*
Equipment Design / instrumentation
Female
Humans
Image Enhancement / instrumentation
Image Processing, Computer-Assisted / instrumentation
Intervertebral Disk / surgery*
Intervertebral Disk Degeneration / surgery*
Lumbar Vertebrae / surgery
Magnetic Resonance Imaging / instrumentation*,  methods
Male
Middle Aged
Patient Selection
Prostheses and Implants*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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