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J Rheumatol. 2020 Feb;47(2):282-289. doi: 10.3899/jrheum.180541. Epub 2019 Apr 15.

Precision, Reliability, and Responsiveness of a Novel Automated Quantification Tool for Cartilage Thickness: Data from the Osteoarthritis Initiative.

Author information

1
From Imorphics Ltd., Manchester; Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds and National Institute for Health Research (NIHR) Leeds Biomedical Research Centre, Leeds, UK.
2
PGC has undertaken consultancies or speaker bureaus for AbbVie, Flexion, Novartis, and Pfizer. MAB, GAG, GRV, CBW, and ADB are employees of Imorphics Ltd., a wholly owned subsidiary of Stryker Corp. M.A. Bowes, PhD, Imorphics Ltd.; G.A. Guillard, PhD, Imorphics Ltd.; G.R. Vincent, PhD, Imorphics Ltd.; A.D. Brett, PhD, Imorphics Ltd.; C.B. Wolstenholme, BSc, Imorphics Ltd.; P.G. Conaghan, MBBS, PhD, FRACP, FRCP, Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds and NIHR Leeds Biomedical Research Centre.
3
From Imorphics Ltd., Manchester; Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds and National Institute for Health Research (NIHR) Leeds Biomedical Research Centre, Leeds, UK. p.conaghan@leeds.ac.uk.
4
PGC has undertaken consultancies or speaker bureaus for AbbVie, Flexion, Novartis, and Pfizer. MAB, GAG, GRV, CBW, and ADB are employees of Imorphics Ltd., a wholly owned subsidiary of Stryker Corp. M.A. Bowes, PhD, Imorphics Ltd.; G.A. Guillard, PhD, Imorphics Ltd.; G.R. Vincent, PhD, Imorphics Ltd.; A.D. Brett, PhD, Imorphics Ltd.; C.B. Wolstenholme, BSc, Imorphics Ltd.; P.G. Conaghan, MBBS, PhD, FRACP, FRCP, Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds and NIHR Leeds Biomedical Research Centre. p.conaghan@leeds.ac.uk.

Abstract

OBJECTIVE:

Accurate automated segmentation of cartilage should provide rapid reliable outcomes for both epidemiological studies and clinical trials. We aimed to assess the precision and responsiveness of cartilage thickness measured with careful manual segmentation or a novel automated technique.

METHODS:

Agreement of automated segmentation was assessed against 2 manual segmentation datasets: 379 magnetic resonance images manually segmented in-house (training set), and 582 from the Osteoarthritis Initiative with data available at 0, 1, and 2 years (biomarkers set). Agreement of mean thickness was assessed using Bland-Altman plots, and change with pairwise Student t test in the central medial femur (cMF) and tibia regions (cMT). Repeatability was assessed on a set of 19 knees imaged twice on the same day. Responsiveness was assessed using standardized response means (SRM).

RESULTS:

Agreement of manual versus automated methods was excellent with no meaningful systematic bias (training set: cMF bias 0.1 mm, 95% CI ± 0.35; biomarkers set: bias 0.1 mm ± 0.4). The smallest detectable difference for cMF was 0.13 mm (coefficient of variation 3.1%), and for cMT 0.16 mm(2.65%). Reported change using manual segmentations in the cMF region at 1 year was -0.031 mm (95% CI -0.022, -0.039), p < 10-4, SRM -0.31 (-0.23, -0.38); and at 2 years was -0.071 (-0.058, -0.085), p < 10-4, SRM -0.43 (-0.36, -0.49). Reported change using automated segmentations in the cMF at 1 year was -0.059 (-0.047, -0.071), p < 10-4, SRM -0.41 (-0.34, -0.48); and at 2 years was -0.14 (-0.123, -0.157, p < 10-4, SRM -0.67 (-0.6, -0.72).

CONCLUSION:

A novel cartilage segmentation method provides highly accurate and repeatable measures with cartilage thickness measurements comparable to those of careful manual segmentation, but with improved responsiveness.

KEYWORDS:

CARTILAGE; KNEE; MAGNETIC RESONANCE IMAGING; OSTEOARTHRITIS

PMID:
30988122
DOI:
10.3899/jrheum.180541

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