Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2005-5-13
pubmed:abstractText
Assessing the displacement of bony implants is an important topic in arthroplasty, particularly in total hip replacement (THR). The observation of the migration is supposed to provide an insight into the fixation of the implant. Diagnostic standard radiographs of the pelvis are an advantageous data source for this purpose. The previous methods based on these images, however, lack of a thorough consideration of their projective nature. They do, hence, not reach the desired precision, which should lie in the submillimeter range to allow a detection of migration in the first one or two years after implantation. The aim of the work presented here was, therefore, a method for measuring the distance of the artificial hip socket to the bone with an error of less than 0.5 mm. The approach has been on the one hand to define the bone-cup distance measured in the radiograph so that the variability of the intrinsic and extrinsic parameters at exposure has a minimal impact. On the other, specialized matching techniques are applied in order to optimize the localization of the necessary bony landmarks and the cup in the X-ray image. The coordinates of the bony landmarks are determined by means of a template matching algorithm. The position of the implant is estimated by intensity-based registration using the cup's CAD-model. The method was validated theoretically, experimentally, and clinically. In the clinical radiographs, the standard deviation of the migration measurements resulted to be 0.28 mm when using only natural bony landmarks. The implantation of a bony marker was found to increase the precision to a standard deviation of 0.20 mm. The interobserver variability in the two cases was estimated to be 0.11 mm and 0.04 mm.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0278-0062
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
676-88
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15889554-Algorithms, pubmed-meshheading:15889554-Arthroplasty, Replacement, Hip, pubmed-meshheading:15889554-Equipment Failure Analysis, pubmed-meshheading:15889554-Hip Joint, pubmed-meshheading:15889554-Hip Prosthesis, pubmed-meshheading:15889554-Humans, pubmed-meshheading:15889554-Imaging, Three-Dimensional, pubmed-meshheading:15889554-Joint Instability, pubmed-meshheading:15889554-Movement, pubmed-meshheading:15889554-Pattern Recognition, Automated, pubmed-meshheading:15889554-Phantoms, Imaging, pubmed-meshheading:15889554-Prosthesis Failure, pubmed-meshheading:15889554-Radiographic Image Enhancement, pubmed-meshheading:15889554-Radiographic Image Interpretation, Computer-Assisted, pubmed-meshheading:15889554-Reproducibility of Results, pubmed-meshheading:15889554-Sensitivity and Specificity
pubmed:year
2005
pubmed:articleTitle
Submillimeter measurement of cup migration in clinical standard radiographs.
pubmed:affiliation
Computer Vision Laboratory, Swiss Federal Institute of Technology (ETH), Gloriastr. 35, 8092 Zürich, Switzerland. tribur@vision.ee.ethz.ch
pubmed:publicationType
Journal Article, Comparative Study, Evaluation Studies, Validation Studies