Method for automatic detection of defective ultrasound linear array transducers based on uniformity assessment of clinical images — A case study

Abstract

The purpose of the present study was to test an idea of and describe a concept of a novel method of detecting defects related to horizontal nonuniformities in ultrasound equipment. The method is based on the analysis of ultrasound images collected directly from the clinical workflow. In total over 31000 images from three ultrasound scanners from two vendors were collected retrospectively from a database. An algorithm was developed and applied to the images, 150 at a time, for detection of systematic dark regions in the superficial part of the images. The result was compared with electrical measurements (FirstCall) of the transducers, performed at times when the transducers were known to be defective. The algorithm made similar detection of horizontal nonuniformities for images acquired at different time points over long periods of time. The results showed good subjective visual agreement with the available electrical measurements of the defective transducers, indicating a potential use of clinical images for early and automatic detection of defective transducers, as a complement to quality control.

Evaluation of an automatic method for detection of defects in linear and curvilinear ultrasound transducers

“…However, by averaging a number of clinical B-mode images, the defect will emerge, since it is present in all images, whereas the anatomical variations tend to cancel each other. In the method proposed to implement this idea, the clinical images are piled in an image stack, which is used to create a Systematic Dark Region (SDR) curve [11]. The SDR curve has a positive value where dark regions are detected in the superficial part of the images and is zero where no dark regions are detected.…”

“…All steps required can be automated and performed by a computer for many transducers at the same time. This method for automatic detection of defective linear ultrasound transducers was, as mentioned before, presented in a previous paper [11], where a detailed description of how the SDR curve is calculated is given.…”

“…The defects that were identified and visualized by the novel method [11] using clinical images showed good visual agreement with FirstCall measurements for a small selection of transducers in the proof of concept study [11], but a thorough evaluation of the method has not up till now been performed. The main purpose of the present study was therefore to perform an extensive evaluation of the novel method and to evaluate it against an established method.…”

“…These quality control tests are recommended to be performed every three months for mobile and emergency room systems and every six months for others in the report of AAPM Ultrasound Task Group No.1 [10]. Recently, a novel method for detecting defective ultrasound linear transducers by analyzing clinical images was introduced in a case study [11]. The method uses the information in the clinical images to find defects that can be seen by assessing the horizontal uniformity.…”

High frequency focused imaging for ultrasonic probe integrity inspection

“…Surface vibrations can be monitored using laser vibrometry [14] to locate possible defects, but this requires specific laser instrumentation which is complex to operate and expensive. A completely different technique is based on the evaluation of the transducers by their B-scan images [15] or air reverberations [16], but this is valid only for the rough estimation of defects. Nevertheless, these techniques do not reveal the presence of local defects so such an inspection might miss the faulty probe.…”