Navicular bone position determined by positional MRI: a reproducibility study.
OBJECTIVE
To examine intraobserver, interobserver and between-day reproducibility of positional MRI for evaluation of navicular bone height (NVH) and medial navicular position (MNP).


METHODS
Positional MRI (pMRI) of the foot was performed on ten healthy participants (0.25 T G-scanner). Scanning was performed in supine and standing position, respectively. Two radiologists evaluated the images in a blinded manner. Reliability and agreement were assessed by calculation of intraclass correlation coefficient (ICC) and 95 % limits of agreement as a percentage of the mean (LOA%).


RESULTS
Intraobserver and interobserver reliability was "substantial" in both supine and standing position (ICC 0.86-0.98) and showed good agreement (LOA% 4.9-14.7 %). Between-day reliability of navicular height and medial navicular position in standing position remained substantial (ICC 0.85-0.92) with adequate agreement (LOA% 8.3-19.8 %). In supine position between-day reliability was "moderate" for NVH (ICC 0.72) and "slight" for MNP (ICC 0.39). Agreement remained adequate between-days for MNP in supine position (LOA% 17.7 %), but it was less than adequate for NVH in supine position (LOA% 24.2 %).


CONCLUSIONS
Navicular height and medial navicular position can be measured by pMRI in a very reproducible manner within and between observers. Increased measurement variation is observed between-days in supine position, which may be due to small positional differences or other unknown biomechanical factors.
Department of Radiology, Copenhagen University Hospital Frederiksberg & Bispebjerg, Nordre Fasanvej 57, Vej 4, Indgang 5, DK-2000, Frederiksberg, Denmark. hansen_philip@hotmail.com.
Philip
P
Hansen
Institute of Sports Medicine Copenhagen, Copenhagen University Hospital Bispebjerg, Copenhagen, NV, Denmark.
Finn E
FE
Johannsen
Parker Institute, Department of Rheumatology, Copenhagen University Hospital Frederiksberg, Frederiksberg, Denmark.
Stine
S
Hangaard
Institute of Sports Medicine Copenhagen, Copenhagen University Hospital Bispebjerg, Copenhagen, NV, Denmark.
Sandra E
SE
Stallknecht
Parker Institute, Department of Rheumatology, Copenhagen University Hospital Frederiksberg, Frederiksberg, Denmark.
Bjarke B
BB
Hansen
Department of Radiology, Copenhagen University Hospital Frederiksberg & Bispebjerg, Nordre Fasanvej 57, Vej 4, Indgang 5, DK-2000, Frederiksberg, Denmark.
Janus D
JD
Nybing
Department of Radiology, Copenhagen University Hospital Frederiksberg & Bispebjerg, Nordre Fasanvej 57, Vej 4, Indgang 5, DK-2000, Frederiksberg, Denmark.|Parker Institute, Department of Rheumatology, Copenhagen University Hospital Frederiksberg, Frederiksberg, Denmark.
Mikael
M
Boesen
D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D011187:Posture / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D016683:Supine Position; D013639:Tarsal Bones / Q000033:anatomy & histology*; D055815:Young Adult
Agreement; Foot posture; Navicular bone; Plantar arch; Positional MRI; Reliability; Reproducibility; Weight-bearing MRI