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Christian Blendl: ImageJ plugin for analyzing the anthropomorphic test patterns in a mammographic test phantom image

Abstract

Background:

A plugin for ImageJ was developed for quality tests in digital mammography. It includes the automatic detection and analysis of the AKP-MDP (German acronym for: Acceptance and constancy test - Mammo Detail Plate) test structures embedded in a test phantom for mammographic X-ray devices. The AKP-MDP test plate is a component of the PAS 1054 (PAS, Public Available Specification: standard in Germany like DIN) test phantom utilized in acceptance and constancy tests for digital mammography devices. The test plate incorporates connatural structures simulating human tissue. Due to the fact, that the test images are usually analyzed visually by various biased observers only, a high variability of results can be expected (intraobserver and interobserver variability). An automatic analysis of the test plate can minimize this problem.

Material and Methods:

The ImageJ plugin detects the PAS1054 phantom body first and extracts the region of the AKP-MDP test plate. The AKP-MDP test plate contains 25 fields with five different structures (polyamide grids, numbers formed by 5-6 small holes, polycarbonate discs, microcalcifications, and gold discs) graded in size and contrast. The plugin finds the regions these structures. Subsequently an analysis of these structures with different methods according to the content of the fields is performed. Prior to the analysis image pre-processing comprises flat-field correction with polynomial fit and selective median filtering before the segmentation step. The actual analyzing process then uses the particle analyzer, the watershed algorithm amongst other methods to detect the structures. Finally the plugin saves the results to an HTML file.

Results:

The ImageJ plugin reports the knots, the angle and the mesh size of the five grids, number and geometrical measures of: the detected circles, the polycarbonate disc, the microcalcifications and the eccentric gold discs. The results are compared to reference samples, which are collected in a separate test procedure (high dose X-ray exposures with low noise). Thus the imaging performance of X-ray devices mapping the anthropomorphic structures can be measured.

Keywords

mammography, PAS1054, phantom images, anthropomorphic structures, X-ray

Administrative data

Presenting author: Christian Blendl
Organisation: Cologne University of Applied Sciences

co-authors: Markus Selbach, Sven Klugmann, Stefan Dickl

Type: Poster (portrait)

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