GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Wiley  (2)
  • 1
    In: Magnetic Resonance in Medicine, Wiley, Vol. 79, No. 3 ( 2018-03), p. 1628-1637
    Abstract: The presence of metallic debris near total hip arthroplasty can have a significant impact on longitudinal patient management. Methods for magnetic resonance imaging‐based quantification of metallic debris near painful total hip replacements are described and applied to cohorts of symptomatic and control subject cases. Methods A combination of metal artifact reduction, off‐resonance mapping, off‐resonance background removal, and spatial clustering methods are utilized to quantify off‐resonance signatures in cases of suspected metallosis. These methods are applied to a cohort of symptomatic hip arthroplasties composed of cobalt‐chromium alloys. Magnetostatic simulations and theoretical principles are used to illuminate the potential sources of the measured off‐resonance effects. Reported metrics from histological tissue assays extracted during surgical revision procedures are also correlated with the proposed magnetic resonance imaging‐based quantification results. Results The presented methods identified quantifiable metallosis signatures in more than 70% of the symptomatic and none of the control cases. Preliminary correlations of the MR data with direct histological evaluation of retrieved tissue samples indicate that the observed off‐resonance effect may be related to tissue necrosis. Conclusions Magnetostatic simulations, theoretical principles, and preliminary histological trends suggest that disassociated cobalt is the source of the observed off‐resonance signature. Magn Reson Med 79:1628–1637, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 1493786-4
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    In: Magnetic Resonance in Medicine, Wiley, Vol. 74, No. 5 ( 2015-11), p. 1349-1355
    Abstract: It has previously been demonstrated that increased overlap of spectral bins in three‐dimensional multispectral imaging techniques (3D‐MSI) can aid in reducing residual artifacts near metal implants. However, increasing spectral overlap also necessitates consideration of saturation effects for species with long T 1 values. Here, an interleaved spectral bin acquisition strategy is presented for overlapping 3D‐MSI that allows for flexible choice of repetition times while simultaneously addressing these cross talk concerns. Methods A phantom imaging experiment is used to illustrate the amplified effect of cross talk on 3D‐MSI acquisitions. A methodological approach to address cross talk across a variety of prescribed repetition times is then described. Using the presented principles, a clinical subject with a total hip replacement was imaged to generate T 1 , proton density, and short‐tau inversion recovery contrasts. In addition, a fracture instrumentation case was imaged pre‐ and postcontrast using T 1 ‐weighted spectrally overlapped 3D‐MSI. Results Phantom results demonstrate that conventional spectral interleaving approaches can generate unwanted signal characteristics in heavily overlapped 3D‐MSI. Clinical images using the presented methods successfully demonstrate T 1 , proton density, and inversion recovery image contrasts using heavily overlapped 3D‐MSI. Conclusions Through automated management of spectral bin distributions across multiple interleaves, a variety of longitudinal magnetization contrasts can efficiently be acquired without any clinically relevant cross‐talk impact using heavily overlapped 3D‐MSI. Magn Reson Med 74:1349–1355, 2015. © 2014 Wiley Periodicals, Inc.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2015
    detail.hit.zdb_id: 1493786-4
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...