Repository for Image Data of Retroverted Subjects

Henak CR, Carruth ED, Anderson AE, Harris MD, Ellis BJ, Peters CL, Weiss JA:  Finite element predictions of cartilage contact mechanics in hips with retroverted acetabula.  Osteoarthritis and Cartilage. In Press.

DOI: http://dx.doi.org/10.1016/j.joca.2013.06.008

Overview

It is difficult to obtain high resolution image data of human hip joints. Therefore, the CT arthrogram image datasets for the subjects included for finite element analysis of cartilage contact stress have been made available. The 10 subjects with normal hip anatomy were made available as part of an earlier study (Harris MD et al., J Orthop Res, 2012, DOI:  http://dx.doi.org/10.1002/jor.22040). The 10 subjects with retroverted acetabula have been made available with this study in order to assist other investigators with the study of the mechanics of the retroverted acetabulum.

Accessing the Image Data

The image data can be downloaded at this address:

https://weisslabutah.org/software/retroverted-hips-image-data

If you have not registered on the MRL site previously, you will be asked to create an account.  Registration allows us to keep track of the use of the image data (number of downloads, who, where).  Your registration information is safe and will not be redistributed.

Separate files are available for each of the 10 subjects.  Each file is a Linux tape archive (tar) file, compressed with GNU Zip (gzip).  Thus each file has the ending “.tar.gz”.  The size of each file is approximately 3 GB.

Under Linux or other Unix operating systems, each individual download can be uncompressed and extracted using the commands:

  • gunzip .tar.gz
  • tar – xvf .tar

This will create a subdirectory containing all of the image data files for the particular subject in DICOM format, as well as a copy of the license agreement and this file.  Each image file represents one slice of the image dataset.

Both gzip and tar are available for Windows, and there are a number of free software tools that can extract .tar.gz files under Windows.

The image files have the extension “.dcm”.  Many image processing, segmentation and visualization programs can open these DICOM files directly.  The free software ImageJ is one option:

http://rsbweb.nih.gov/ij/

To open an image stack in Image J, choose “Import” from the “File” menu, and then choose “Image Sequence”.  Choose the first image in the stack and then click “Open”.

Subject Information

Subjects with retroverted acetabula were recruited for our study from patients being treated in our clinic for hip pain secondary to acetabular retroversion.  The basic characteristics of these subjects are listed in the table below.

Subject NumberAge (years)GenderWeight (kg)Height (cm)BMI (kg∙m-2)
OAC0123F5116419
OAC0234M10319427
OAC0318M6916226
OAC0420M7418322
OAC0536M9518927
OAC0622M9018726
OAC0727M8718924
OAC0819M9119125
OAC0920M6017121
OAC1018M8618824

 

Image Acquisition

CT images were acquired at the University of Utah Hospital. Each subject with acetabular retroversion was being seen at the University of Utah Orthopedics Center for hip pain.  The hip which was being evaluated clinically was selected for CT arthrogram.  The hip capsule was injected with ~20 ml of contrast agent (2:1 Xylocaine to OMNIPAQUE® 350, GE Healthcare Inc., Princeton, NJ) under fluoroscopic guidance.  CT images of both femurs and the entire pelvis were acquired following injection of the contrast agent.  Joint traction was applied during the CT scan using a hare traction device. The images below indicate the bone and cartilage regions in the image data.

 

Resampled Image Information

CT images were resampled to improve the resolution of the segmentation masks.  Resampled images are provided for download.  All images have a resampled in-plane resolution of 1536 × 1536, an original in-plane resolution of 512 × 512 and a bit depth of 16.

Subject NumberResampled in-plane resolution (mm)Original in-plane resolution (mm)Resampled slice thickness (mm)Original slice thickness (mm)
OAC010.2473150.7421880.3332961.5
OAC020.2584630.7753890.3333311.0
OAC030.2473960.7421880.2333330.7
OAC040.2604160.7812490.2333330.7
OAC050.2513020.7539060.2333330.7
OAC060.2897130.8691390.3333331.0
OAC070.2513020.7539060.3333331.0
OAC080.2376310.7128920.3333331.0
OAC090.2740890.8222660.3333331.0
OAC100.3255210.9765640.3333311.0