Quantitative evaluation of tendon enthesis using ultrashort echo time magnetic resonance imaging (UTE-MRI) techniques

Jerban, Saeed; Lombardi, Alecio; Ma, Yajun; Afsahi, Amir Masoud; Moazamian, Dina; Athertya, Jiyo S.; Jang, Hyungseok; Chung, Christine B.; Du, Jiang; Chang, Eric Y.

doi:10.58530/2022/4435

Cited by 1 publication

(1 citation statement)

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“…The ultrashort TE (UTE) 39 technique has also been used for short-T 2 brain imaging. [40][41][42][43][44][45][46][47][48] In UTE, gradient ramping is performed during signal readout, which avoids some of the technical constraints faced by the ramp-first sequence design but limits the achievable spatial encoding speed. Consequently, UTE is primarily sensitive to signals with T 2 s in the hundreds of microseconds range, which excludes the majority of myelin bilayer signals.…”

Section: Related Techniquesmentioning

confidence: 99%

Myelin bilayer mapping in the human brain in vivo

Baadsvik,

Weiger,

Froidevaux

et al. 2024

Magnetic Resonance in Med

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PurposeTo quantitatively map the myelin lipid‐protein bilayer in the live human brain.MethodsThis goal was pursued by integrating a multi‐TE acquisition approach targeting ultrashort T2 signals with voxel‐wise fitting to a three‐component signal model. Imaging was performed at 3 T in two healthy volunteers using high‐performance RF and gradient hardware and the HYFI sequence. The design of a suitable imaging protocol faced substantial constraints concerning SNR, imaging volume, scan time, and RF power deposition. Model fitting to data acquired using the proposed protocol was made feasible through simulation‐based optimization, and filtering was used to condition noise presentation and overall depiction fidelity.ResultsA multi‐TE protocol (11 TEs of 20–780 μs) for in vivo brain imaging was developed in adherence with applicable safety regulations and practical scan time limits. Data acquired using this protocol produced accurate model fitting results, validating the suitability of the protocol for this purpose. Structured, grainy texture of myelin bilayer maps was observed and determined to be a manifestation of correlated image noise resulting from the employed acquisition strategy. Map quality was significantly improved by filtering to uniformize the k‐space noise distribution and simultaneously extending the k‐space support. The final myelin bilayer maps provided selective depiction of myelin, reconciling competitive resolution (1.4 mm) with adequate SNR and benign noise texture.ConclusionUsing the proposed technique, quantitative maps of the myelin bilayer can be obtained in vivo. These maps offer unique information content with potential applications in basic research, diagnosis, disease monitoring, and drug development.

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