The role of quality assurance and quality control in improving the diagnostic accuracy of obstetric ultrasound: A Literature review.

Abstract

The importance of achieving accurate foetal measurements in obstetric ultrasound is widely understood to allow high quality assessment of foetal growth and development. Ultrasound has been widely accepted as the routine method of diagnosis in the obstetric field for foetal abnormalities due to its accessibility and efficiency in diagnosis. Yet, the operation dependent nature of ultrasound causes calculations to be prone to error that may drastically affect foetal measurements recorded and the outcome of the foetus. In this review, various studies focused on quality assurance and quality control are summarised with their results and limitations discussed. Furthermore, related issues including the potential of bias in self appraisal of image quality, inaccurate growth charts and operator related factors are highlighted to be hindering the progress of the optimisation of obstetric ultrasound.  Additionally, future research in nuchal translucency and foetal biometry acquisition regarding the vast developments in ultrasound technology and techniques proposed to increase ease of use and diagnostic accuracy will be discussed. Literature was obtained from online databases such as Ovid Medline, Scopus and PubMed using keywords such as “Obstetric ultrasound”, “Quality assurance” and “Quality control”. The scope of literature was broadened to compensate by discussing quality assurance measurements at different gestational phases; such as “Fetal biometry” and “Nuchal Translucency”, as well as including experimental designs focused on quality assurance of image reporting, as optimisation of images are not limited to the image collection but also the interpretation and reporting of those images. In a review of current literature addressing the quality control and assurance of obstetric sonography, a common agreement is that implementation of quality assurance measures will increase fetal measurement reliability significantly. Although there is variability to the strategies, there is still a lack of a standardised framework for the assessment of quality assurance across clinical sites of the modality.

Introduction

Obstetric sonography is a major modality used for the measurement of fetal weight, anatomical anomalies, and general fetal wellbeing. This modality has seen an exponential growth in application and technological advancements however, optimisation and guarantee of image quality remains an overlooked and neglected aspect in literature due to poor resources and efficiency associated with quality assurance measures. However, there is an importance for image quality measures to address the variance of the quality of studies and consequences due to the operator dependent nature of sonography. Assessment and guarantee of image quality involve the implementation of quality assurance and quality control systems (Salomon). This literature review intends to explore the current state of quality assurance measures in obstetric sonography, describe standardised improvements to inter and intra-operator reliability, and identify why quality assurance and quality control systems are so important for obstetric ultrasound. Quality assurance will be defined as the implementation of systematic and planned tasks in a system to demonstrate a determined standard of image quality and their conditions will be met consistently (Salomon). This system aims to guarantee consistent acquisition of high-quality images. Quality control is defined as evaluations of techniques or activities that monitor quality to ensure consistent high-quality delivery of images (Hediger M). Resource management, such as cost efficiency, time constraint and effective equipment usage are highly prioritised in the increasingly demanding setting of the medical field (Salomon). Though the sensitivity and precision of fetal anatomy are higher in other modalities such as Magnetic Resonance Imaging (MRI), sonography is the primary modality fetal measurement for its faster image acquisition and low cost. This prioritisation raises questions in various literature on the practicality and impact of implementing image quality measures, despite some literature suggestion of increased reliability and accuracy of measurements from the application of various quality assurance and control methods (Russell S).

Process of analysing literature

Literature was obtained from online databases such as Ovid Medline, Scopus and PubMed using keywords such as “Obstetric ultrasound”, “Quality assurance” and “Quality control” for a broad topic search. However, the literature was limited, as the topic is largely neglected. Therefore the scope of literature was broadened to compensate by discussing quality assurance measurements at different gestational phases; such as “Fetal biometry” and “Nuchal Translucency”, as well as including experimental designs focused on quality assurance of image reporting, as optimisation of images are not limited to the image collection but also the interpretation and reporting of those images (1). Sources were selected based on peer-review, date of publication, experimental design and whether it was a large-scale study to ensure that the ultrasound protocol reviewed is the most recent and applicable to modern settings. Measurements of nuchal translucency (NT) and crown rump length (CRL) were chosen as the preferred parameters for obstetric sonography of the first trimester to calculate the gestational age, and foetal biometry measurements for the later trimesters to characterise foetal growth rate.

Quality Assurance and Con