Design and application of an MR reference phantom for multicentre lung imaging trials

Abstract

IntroductionAs there is an increasing number of multicentre lung imaging studies with MRI in patients, dedicated reference phantoms are required to allow for the assessment and comparison of image quality in multi-vendor and multi-centre environments. However, appropriate phantoms for this purpose are so far not available commercially. It was therefore the purpose of this project to design and apply a cost-effective and simple to use reference phantom which addresses the specific requirements for imaging the lungs with MRI.MethodsThe phantom was designed to simulate 4 compartments (lung, blood, muscle and fat) which reflect the specific conditions in proton-MRI of the chest. Multiple phantom instances were produced and measured at 15 sites using a contemporary proton-MRI protocol designed for an in vivo COPD study at intervals over the course of the study. Measures of signal- and contrast-to-noise ratio, as well as structure and edge depiction were extracted from conventionally acquired images using software written for this purpose.ResultsFor the signal to noise ratio, low intra-scanner variability was found with 4.5% in the lung compartment, 4.0% for blood, 3.3% for muscle and 3.7% for fat. The inter-scanner variability was substantially higher, with 41%, 32%, 27% and 32% for the same order of compartments. In addition, measures of structure and edge depiction were found to both vary significantly among several scanner types and among scanners of the same model which were equipped with different gradient systems.ConclusionThe described reference phantom reproducibly quantified image quality aspects and detected substantial inter-scanner variability in a typical pulmonary multicentre proton MRI study, while variability was greater in lung tissue compared to other tissue types. Accordingly, appropriate reference phantoms can help to detect bias in multicentre in vivo study results and could also be used to harmonize equipment or data.

An Analysis for Key Indicators of Reproducibility in Radiology

“…(29) Investigators should be encouraged to take notes of analysis coding and scripts so as to be able to create a detailed explanation to be published with the study. (30–32) Providing such analysis scripts could improve the reproducibility of study outcomes and serve as a guide for future radiology publications to follow. (26)…”

Quantification of pulmonary perfusion abnormalities using DCE-MRI in COPD: comparison with quantitative CT and pulmonary function

“…All subjects underwent MRI using the same 1.5 T scanner (Magnetom Aera, Siemens Healthineers) using a standardized chest MRI protocol (Supplementary table 1) [3,19,20], validated by a phantom study [21]. For the DCE-MRI perfusion imaging, a time-resolved T1-weighted 3D keyhole pulse sequence (time-resolved angiography with interleaved stochastic trajectories [TWIST]) with a fixed dose of 2 ml gadolinium-based CA (Gadobutrol, Bayer Vital GmbH) was injected i.v.…”

The radiological diagnosis of bronchiectasis: what's in a name?

“…As for CT, consensus on the classification of bronchiectasis is lacking. Furthermore, standardisation across centres and vendors for lung MRI is in its early days [49][50][51]. However, there have been important developments that may significantly contribute to the future of bronchiectasis research, as follows.…”