Synthetic Mri of the Brain in a Clinical Setting

Abstract

Background: Conventional magnetic resonance imaging (MRI) has relatively long scan

Synthetic MRI for Clinical Neuroimaging: Results of the Magnetic Resonance Image Compilation (MAGiC) Prospective, Multicenter, Multireader Trial

“…5,[15][16][17][18] Synthetic imaging exhibited characteristic hyperintense artifacts in FLAIR views, corroborating previous reports that further work will be necessary before synthetically generated FLAIR views can fully replace conventional FLAIR in practice. 5,6 While FLAIR artifacts contributed to lower overall image quality scores (because all views were considered in this composite primary end point), the overall impact of FLAIR artifacts on diagnosis was inherently limited by the nature of the synthetic views, in which immediate cross-comparison with other contrast views is possible. On rare occasions, encoding artifacts in FLAIR views could necessitate clinical workflow changes such as the addition of a single conventional scan; however, the impact on the patient's overall scan experience is offset by the time savings of the synthetic acquisition.…”

“…The primary hypothesis is 1-sided and can be stated as H 0 :S Յ Ϫ⌬ and H A :S Ͼ Ϫ⌬, where the S is the median difference of overall diagnostic image quality across readers for synthetic-versus-conventional MR imaging, in which noninferiority is established by rejecting the null hypothesis. The margin (⌬) of .5 was determined statistically on the basis of the population and was confirmed by clinical estimates from prior research 5 and institutional pilot data, in accordance with recommendations for determination of noninferiority margins described in the US Food and Drug Administration Guidance for Industry: Non-Inferiority Clinical Trials to Establish Effectiveness (2016) (https://www.fda.gov/ downloads/Drugs/GuidanceComplianceRegulatoryInformation/ Guidances/UCM202140.pdf) and trial designs for noninferiority testing in radiology reviewed by Ahn et al (2012).…”

“…MDME parameters acquired in 1 scan are used in synthetic imaging to calculate pixel intensity, producing an appearance similar to that of conventional MR images with modifiable TE, TR, and TI. 5,11 Thus, synthetic (based on MDME) and conventional T1, T2, T1 FLAIR, T2 FLAIR, PD, and STIR contrast views were collected. MDME data were reconstructed outside the clinical care environment by using MAGnetic resonance image Compilation (MAGiC) software on a 64-bit Advantage Workstation (GE Healthcare, Milwaukee, Wisconsin).…”

“…4 This advancement may help improve throughput and reduce rescanning, while also providing quantitative information of research interest. [4][5][6] Clinical studies of synthetic MR imaging are highly heterogeneous in that they examine a variety of conditions with widely varying scan parameters, with a paucity of large, randomized trials to inform clinical usage. 3,6 Blystad et al 5 (2012) reported that synthetic images had diagnostic utility similar to that of conventional imaging series, though with some quality issues like granulation and contrast particularly apparent in FLAIR views.…”

“…[4][5][6] Clinical studies of synthetic MR imaging are highly heterogeneous in that they examine a variety of conditions with widely varying scan parameters, with a paucity of large, randomized trials to inform clinical usage. 3,6 Blystad et al 5 (2012) reported that synthetic images had diagnostic utility similar to that of conventional imaging series, though with some quality issues like granulation and contrast particularly apparent in FLAIR views. Other studies reported good quality and contrast for synthetic images among certain indications, such as multiple sclerosis, brain metastasis, 6,7 and myelination patterns.…”