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Total knee arthroplasty MRI featuring slice-encoding for metal artifact correction: reduction of artifacts for STIR and proton density-weighted sequences


Sutter, Reto; Hodek, Roman; Fucentese, Sandro F; Nittka, Mathias; Pfirrmann, Christian W A (2013). Total knee arthroplasty MRI featuring slice-encoding for metal artifact correction: reduction of artifacts for STIR and proton density-weighted sequences. American Journal of Roentgenology, 201(6):1315-1324.

Abstract

OBJECTIVE: The purpose of this article is to compare slice-encoding for metal artifact correction (SEMAC) sequences versus optimized standard MRI sequences in patients with total knee arthroplasty (TKA).
SUBJECTS AND METHODS: Forty-two patients with TKA underwent 1.5-T MRI. Sequences optimized for metal implant imaging (SEMAC) were compared with standard sequences optimized with high bandwidth for STIR and proton density (PD)-weighted images. In 29 patients, CT was available as reference standard. Signal void and insufficient fat saturation were quantified. Qualitative criteria (anatomy, distortion, blurring, and noise) were assessed on a 5-point scale (1, no artifacts; 5, severe artifacts) by two readers. Abnormal imaging findings were noted. A Student t test and a Wilcoxon signed rank test was used for statistics.
RESULTS: Signal void areas and insufficient fat saturation were smaller for the SEMAC sequences than for the optimized standard sequences (p ≤ 0.005 for all comparisons). Depiction of anatomic structures was better on STIR with SEMAC versus standard sequences optimized with high bandwidth (score range, 2.9-3.7 vs 4.2-4.9) and on PD-weighted imaging with SEMAC versus standard sequences optimized with high bandwidth (score range, 2.5-3.5 vs 3.1-3.8), which was statistically significant (p < 0.001 to p = 0.007 for different structures). Distortion and noise were lower for SEMAC than for the standard sequences (p ≤ 0.001), whereas no technique had a clear advantage for blurring. Detection of abnormal imaging findings was markedly increased for the SEMAC technique (p < 0.001) and was most pronounced for STIR images (98 and 74 findings for STIR with SEMAC for readers 1 and 2, respectively, vs 37 and 37 findings for readers 1 and 2, respectively, for STIR with standard sequences optimized with high bandwidth). Sensitivity for detection of periprosthetic osteolysis was improved for STIR with SEMAC (100% and 86% for readers 1 and 2, respectively) compared with STIR with standard sequences optimized with high bandwidth (14% and 29% for readers 1 and 2, respectively).
CONCLUSION: SEMAC sequences showed a statistically significant artifact reduction. The detection of clinically relevant findings such as periprosthetic osteolysis was markedly improved.

Abstract

OBJECTIVE: The purpose of this article is to compare slice-encoding for metal artifact correction (SEMAC) sequences versus optimized standard MRI sequences in patients with total knee arthroplasty (TKA).
SUBJECTS AND METHODS: Forty-two patients with TKA underwent 1.5-T MRI. Sequences optimized for metal implant imaging (SEMAC) were compared with standard sequences optimized with high bandwidth for STIR and proton density (PD)-weighted images. In 29 patients, CT was available as reference standard. Signal void and insufficient fat saturation were quantified. Qualitative criteria (anatomy, distortion, blurring, and noise) were assessed on a 5-point scale (1, no artifacts; 5, severe artifacts) by two readers. Abnormal imaging findings were noted. A Student t test and a Wilcoxon signed rank test was used for statistics.
RESULTS: Signal void areas and insufficient fat saturation were smaller for the SEMAC sequences than for the optimized standard sequences (p ≤ 0.005 for all comparisons). Depiction of anatomic structures was better on STIR with SEMAC versus standard sequences optimized with high bandwidth (score range, 2.9-3.7 vs 4.2-4.9) and on PD-weighted imaging with SEMAC versus standard sequences optimized with high bandwidth (score range, 2.5-3.5 vs 3.1-3.8), which was statistically significant (p < 0.001 to p = 0.007 for different structures). Distortion and noise were lower for SEMAC than for the standard sequences (p ≤ 0.001), whereas no technique had a clear advantage for blurring. Detection of abnormal imaging findings was markedly increased for the SEMAC technique (p < 0.001) and was most pronounced for STIR images (98 and 74 findings for STIR with SEMAC for readers 1 and 2, respectively, vs 37 and 37 findings for readers 1 and 2, respectively, for STIR with standard sequences optimized with high bandwidth). Sensitivity for detection of periprosthetic osteolysis was improved for STIR with SEMAC (100% and 86% for readers 1 and 2, respectively) compared with STIR with standard sequences optimized with high bandwidth (14% and 29% for readers 1 and 2, respectively).
CONCLUSION: SEMAC sequences showed a statistically significant artifact reduction. The detection of clinically relevant findings such as periprosthetic osteolysis was markedly improved.

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15 citations in Web of Science®
15 citations in Scopus®
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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Balgrist University Hospital, Swiss Spinal Cord Injury Center
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2013
Deposited On:03 Feb 2014 16:07
Last Modified:05 Apr 2016 17:27
Publisher:American Roentgen Ray Society
ISSN:0361-803X
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.2214/AJR.13.10531
PubMed ID:24261373

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