title: Precision of volumetric assessment of proximal femur microarchitecture from high-resolution 3T MRI.
abstract: OBJECTIVE
  To evaluate the precision of measures of bone volume and bone volume fraction derived from high-resolution 3T MRI of proximal femur bone microarchitecture using non-uniformity correction.
  
  
  METHODS
  This HIPAA compliant, institutional review board approved study was conducted on six volunteers (mean age 56 ± 13 years), and written informed consent was obtained. All volunteers underwent a 3T FLASH MRI hip scan at three time points: baseline, second scan same day (intra-scans), and third scan one week later (inter-scans). Segmentation of femur images and values for total proximal femur volume (T), bone volume (B), and bone volume fraction (BVF) were calculated using in-house developed software, FireVoxel. Two types of non-uniformity corrections were applied to images (N3 and BiCal). Precision values were calculated using absolute percent error (APE). Statistical analysis was carried out using one-sample one-sided t test to observe the consistency of the precision and paired t test to compare between the various methods and scans.
  
  
  RESULTS
  No significant differences in bone volume measurements were observed for intra- and inter-scans. When using non-uniformity correction and assessing all subjects uniformly at the level of the lesser trochanter, precision values overall improved, especially significantly (p < 0.05) when measuring bone volume, B . B values using the combination of N3 or BiCal with CLT had a significant consistent APE values of less than 2.5 %, while BVF values were all consistently and significantly lower than 2.5 % APE.
  
  
  CONCLUSIONS
  Our results demonstrate the precision of high-resolution 3D MRI measures were comparable to that of dual-energy X-ray absorptiometry. Additional corrections to the analysis technique by cropping at the lesser trochanter or using non-uniformity corrections helped to improve precision. The high precision values from these MRI scans provide evidence for MRI of the proximal femur as a promising tool for osteoporosis diagnosis and treatment.
authors.affiliation: Department of Radiology, NYU Langone Medical Center, Center for Biomedical Imaging, New York University, 660 First Ave. 4th Floor, New York, NY, 10016, USA, Alexandra.Hotca-Cho@nyumc.org.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Hotca
authors.forename: Shreyas
authors.initials: S
authors.lastname: Ravichandra
authors.forename: Artem
authors.initials: A
authors.lastname: Mikheev
authors.forename: Henry
authors.initials: H
authors.lastname: Rusinek
authors.forename: Gregory
authors.initials: G
authors.lastname: Chang
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D000368:Aged; D015519:Bone Density; D005260:Female; D005269:Femur / Q000033:anatomy & histology*; D006621:Hip Joint / Q000033:anatomy & histology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010024:Osteoporosis / Q000473:pathology*; D015203:Reproducibility of Results; D012984:Software