Automatic Location of Vertebrae on DXA Images Using Random Forest Regression

  • M. G. Roberts
  • Timothy F. Cootes
  • J. E. Adams
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7512)

Abstract

We provide a fully automatic method of segmenting vertebrae in DXA images. This is of clinical relevance to the diagnosis of osteoporosis by vertebral fracture, and to grading fractures in clinical trials. In order to locate the vertebrae we train detectors for the upper and lower vertebral endplates. Each detector uses random forest regressor voting applied to Haar-like input features. The regressors are applied at a grid of points across the image, and each tree votes for an endplate centre position. Modes in the smoothed vote image are endplate candidates, some of which are the neighbouring vertebrae of the one sought. The ambiguity is resolved by applying geometric constraints to the connections between vertebrae, although there can be some ambiguity about where the sequence starts (e.g. is the lowest vertebra L4 or L5, Fig 2a). The endplate centres are used to initialise a final phase of Active Appearance Model search for a detailed solution. The method is applied to a dataset of 320 DXA images. Accuracy is comparable to manually initialised AAM segmentation in 91% of images, but multiple grade 3 fractures can cause some edge confusion in severely osteoporotic cases.

Keywords

Vertebral Fracture Random Forest Vertebral Fracture Assessment Active Appearance Model Lower Endplate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • M. G. Roberts
    • 1
  • Timothy F. Cootes
    • 1
  • J. E. Adams
    • 1
  1. 1.Imaging Science Research GroupUniversity of ManchesterU.K.

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