Radiographie du thorax

vignette|Image A: Radiographie du thorax normale. Image B: image de pneumonie atypique (fièvre Q). La radiographie du thorax est une technique d' à base de rayons X permettant de diagnostiquer des pathologies atteignant ou retentissant sur le thorax et ses composantes : atteintes du médiastin, infections pulmonaires, pneumothorax, décompensation cardiaque.. Données statistiques Il s'agit de l'un des examens radiologiques les plus pratiqués. En France, selon la Haute Autorité de santé (HAS) en 2006, 4,4 millions de radiographies du thorax ont été réalisés sur une population de 63 millions de personnes. Technique L'aspect technique de la radiographie du thorax se fonde sur la projection de rayons X à travers le corps pour atteindre une plaque de capture numérique ou un film. Radiographie standard Pour obtenir une image de face, le patient se tient debout, la partie antérieure du tronc accolée à la plaque de capture et l'émetteur dans son dos. On parle

Predrilled locking compression plate is more accurate than tension band wiring in restoring articular geometry of the ulnar greater sigmoid notch after olecranon Chevron osteotomy

Alexandre Terrier, Frédéric Vauclair

Introduction: The olecranon Chevron osteotomy (OCO) is commonly used to approach complex intraarticular fractures of the distal humerus. Predrilled tension band wiring (TBW) has historically been used to fix OCO. However, clinical outcomes are burdened by secondary loss of reduction and up to 21.3% non-union rates. The biomechanical stability of anatomic locking compression plate (LCP) was reported to be superior to TBW in olecranon fracture fixation. We hypothesised that this implant may also be superior to TBW in the anatomic reconstruction of the articular surfaces of the ulnar greater sigmoid notch after OCO by predrilling the holes of the angular stable plate with the threaded drill guide prior to osteotomy. Materials and methods: Lateral standardised and calibrated radiographs of twenty synthetic ulnar bones were obtained using a custom-made holder prior to preparation by a senior orthopaedic trauma surgeon. Ten specimens were then predrilled using the threaded drill bit guide of an olecranon LCP, while the other ten samples were predrilled with two 1.6 mm Kirschner wires. A distal "V" OCO was performed using a 0.6 mm oscillating saw. After repositioning and fixation with the corresponding device, lateral radiographs were repeated. Two independent observers used the TraumaCad planning software to document the articular geometry of the ulnar greater sigmoid notch pre- and postoperatively. The diameter of the best-fitting circle (diameter), the distance between the tip of the coronoid and the olecranon processes (distance) and the maximum articular depth were measured. Results: With the TBW technique, after OCO and fixation, all three postoperative measurements were significantly (p = 0.13). Inter and intra-observer measurement reliability was strong to very strong (intraclass correlation coefficients >= 0.793) for all three variables. Conclusion: Our study reveals that the predrilled LCP technique is more accurate than the predrilled TBW in restoring the anatomic articular geometry of the ulnar greater sigmoid notch after OCO. (C) 2020 Elsevier Ltd. All rights reserved.

ELSEVIER SCI LTD2020

Philippe Thévenaz, Michaël Unser, Xiuwei Zhang

One of the main factors that affect the accuracy of intensity-based registration of two-dimensional (2D) X-ray fluoroscopy to three-dimensional (3D) CT data is the similarity measure, which is a criterion function that is used in the registration procedure for measuring the quality of image match. This paper presents a unifying framework for rationally deriving point similarity measures based on Markov random field (MRF) modeling of difference images which are obtained by comparing the reference fluoroscopic images with their associated digitally reconstructed radiographs (DRR's). The optimal solution is defined as the maximum a posterior (MAP) estimate of the MRF. Three novel point similarity measures derived from this framework are presented. They are evaluated using a phantom and a human cadaveric specimen. Combining any one of the newly proposed similarity measures with a previously introduced spline-based registration scheme, we develop a fast and accurate registration algorithm. We report their capture ranges, converging speeds, and registration accuracies.

Springer2006

Geometric Alignment and Chromatic Calibration of Serial Radiographic Images

Philippe Thévenaz

Objective—To develop software for automated registration and intensity calibration of serial dental radiographs for the analysis of longitudinal changes in bone density. Methods—Serial dental radiographs were acquired using a positioning device designed to minimize projection divergence. Each radiograph included an image of a standardized aluminium wedge. The radiographs were scanned on a flatbed scanner (AGFA Duo Scan) with a spatial resolution of 300 dpi, and pixel intensity coded in 16-bit grey scale. The intensity was calibrated using serial images of selected areas with defined thickness of the aluminium wedge. A robust B-splines multiresolution registration algorithm was implemented to overcome the acquisition misalignment. Radiographs, taken before and after periodontal therapy, were subtracted to assess bone density evolution. Results—The intensity calibration decreased the maximum intensity variations between serial radiographs from 30±17% to 1±1% (mean±standard deviation), and improved the visual comparison between the radiographs. The registration stage allowed correcting the misalignment of the radiographs on the scanner screen and superimposing the radiography contents. The observed residual motion was about 0.02±0.01 mm. Conclusion—Very user-friendly software was developed. The manipulator needs to scan the radiographs only one time. The software performs all subsequent processing steps.

The British Institute of Radiology2004

Predrilled locking compression plate is more accurate than tension band wiring in restoring articular geometry of the ulnar greater sigmoid notch after olecranon Chevron osteotomy

Alexandre Terrier, Frédéric Vauclair

ELSEVIER SCI LTD2020

Predrilled locking compression plate is more accurate than tension band wiring in restoring articular geometry of the ulnar greater sigmoid notch after olecranon Chevron osteotomy

Point Similarity Measures Based on MRF Modeling of Difference Images for Spline-Based 2D-3D Rigid Registration of x-Ray Fluoroscopy to CT Images

Geometric Alignment and Chromatic Calibration of Serial Radiographic Images

Predrilled locking compression plate is more accurate than tension band wiring in restoring articular geometry of the ulnar greater sigmoid notch after olecranon Chevron osteotomy

Point Similarity Measures Based on MRF Modeling of Difference Images for Spline-Based 2D-3D Rigid Registration of x-Ray Fluoroscopy to CT Images

Geometric Alignment and Chromatic Calibration of Serial Radiographic Images