Accurate super-resolution low-field brain MRI

Iglesias, Juan Eugenio; Schleicher, Riana; Laguna, Sonia; Billot, Benjamin; Schaefer, Pamela W.; McKaig, Brenna; Goldstein, Joshua N.; Sheth, Kevin N; Rosen, Matthew S.; Kimberly, W. Taylor

doi:10.48550/arxiv.2202.03564

Cited by 3 publications

(2 citation statements)

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“…32 To facilitate coregistration, we first synthesized 1-mm isotropic T1 MP-RAGE-like images from the HF-DWI and LF-FLAIR scans using SynthSR. 33,34 These were segmented with SynthSeg 35,36 which enabled creation of binary masks of the total intracranial volume (Fig. S1).…”

Section: Quantitative Flair Analysismentioning

confidence: 99%

Diffusion‐Weighted Imaging Fluid‐Attenuated Inversion Recovery Mismatch on Portable, Low‐Field Magnetic Resonance Imaging Among Acute Stroke Patients

Sorby‐Adams,

Guo,

de Havenon

et al. 2024

Annals of Neurology

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ObjectiveFor stroke patients with unknown time of onset, mismatch between diffusion‐weighted imaging (DWI) and fluid‐attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) can guide thrombolytic intervention. However, access to MRI for hyperacute stroke is limited. Here, we sought to evaluate whether a portable, low‐field (LF)‐MRI scanner can identify DWI‐FLAIR mismatch in acute ischemic stroke.MethodsEligible patients with a diagnosis of acute ischemic stroke underwent LF‐MRI acquisition on a 0.064‐T scanner within 24 h of last known well. Qualitative and quantitative metrics were evaluated. Two trained assessors determined the visibility of stroke lesions on LF‐FLAIR. An image coregistration pipeline was developed, and the LF‐FLAIR signal intensity ratio (SIR) was derived.ResultsThe study included 71 patients aged 71 ± 14 years and a National Institutes of Health Stroke Scale of 6 (interquartile range 3–14). The interobserver agreement for identifying visible FLAIR hyperintensities was high (κ = 0.85, 95% CI 0.70–0.99). Visual DWI‐FLAIR mismatch had a 60% sensitivity and 82% specificity for stroke patients <4.5 h, with a negative predictive value of 93%. LF‐FLAIR SIR had a mean value of 1.18 ± 0.18 <4.5 h, 1.24 ± 0.39 4.5–6 h, and 1.40 ± 0.23 >6 h of stroke onset. The optimal cut‐point for LF‐FLAIR SIR was 1.15, with 85% sensitivity and 70% specificity. A cut‐point of 6.6 h was established for a FLAIR SIR <1.15, with an 89% sensitivity and 62% specificity.InterpretationA 0.064‐T portable LF‐MRI can identify DWI‐FLAIR mismatch among patients with acute ischemic stroke. Future research is needed to prospectively validate thresholds and evaluate a role of LF‐MRI in guiding thrombolysis among stroke patients with uncertain time of onset. ANN NEUROL 2024

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Section: Quantitative Flair Analysismentioning

confidence: 99%

Diffusion‐Weighted Imaging Fluid‐Attenuated Inversion Recovery Mismatch on Portable, Low‐Field Magnetic Resonance Imaging Among Acute Stroke Patients

Sorby‐Adams,

Guo,

de Havenon

et al. 2024

Annals of Neurology

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show abstract

“…Machine learning algorithms have been shown to boost the performance in other low-field systems and can be readily incorporated to ours. These can be used, via transfer learning, to increase the spatial resolution of scans a posteriori based on multiple acquisitions, prior knowledge about the sample 40 , or with networks trained with paired datasets of low and high-field images, to recover from the former features visible otherwise only with the latter 32,41 . Deep learning and convolutional neural networks can also be employed to increase reconstruction quality through image denoising, artifact detection and active noise cancellation 31,42,43 .…”

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confidence: 99%