Myelin Imaging Using 3D Dual-echo Ultra-short Echo Time MRI with Rosette k-Space Pattern

Purpose: This study aimed to develop a new 3D dual-echo rosette k-space trajectory, specifically for applications of ultra-short echo time (UTE) magnetic resonance imaging (MRI). The direct imaging of the myelin bilayer, which has ultra-short transverse relaxation time (uT2), was acquired to test the performance of the proposed UTE sequence. Theory and Methods: The rosette trajectory was developed based on rotations of a "petal-like" pattern in the kx-ky plane, with oscillated extensions in kz-direction for 3D coverage. Five healthy volunteers were recruited and underwent ten dual-echo rosette UTE scans with varied echo times (TEs). Dual-exponential model fitting was performed to separate uT2 signals, with the output of uT2 fraction, uT2 value and long T2 value. Results: The reconstructed images' signal contrast between white matter (WM) and grey matter (GM) increased with longer TEs. The WM regions had higher uT2 fraction values than GM (10.9% ± 1.9% vs. 5.7% ± 2.4%). The uT2 value was about 0.12 milliseconds in WM. Conclusion: The higher uT2 fraction value in WM compared to GM demonstrated the ability of the proposed sequence to capture rapidly decaying signals.

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Cluster-based segmentation of dual-echo ultra-short echo time images for PET/MR bone localization

EJNMMI Physics ◽

10.1186/2197-7364-1-7 ◽

2014 ◽

Vol 1 (1) ◽

pp. 7 ◽

Cited By ~ 13

Author(s):

Gaspar Delso ◽

Konstantinos Zeimpekis ◽

Michael Carl ◽

Florian Wiesinger ◽

Martin Hüllner ◽

...

Keyword(s):

Echo Time ◽

Short Echo Time ◽

Dual Echo

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Imaging in Psoriasis and Psoriatic Arthritis: GRAPPA 2008

The Journal of Rheumatology ◽

10.3899/jrheum.090955 ◽

2010 ◽

Vol 37 (2) ◽

pp. 448-452 ◽

Cited By ~ 13

Author(s):

LAURA C. COATES ◽

DENNIS M. McGONAGLE ◽

RICHARD HODGSON ◽

PAOLO GISONDI ◽

ARTHUR F. KAVANAUGH ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Psoriatic Arthritis ◽

Pathological Change ◽

Resonance Imaging ◽

Group Discussions ◽

Echo Time ◽

Magnetic Resonance Imaging Mri ◽

Primary Focus ◽

Short Echo Time

At the 2008 meeting of GRAPPA (Group for Research and Assessment of Psoriasis and Psoriatic Arthritis), the primary focus of the imaging session was the enthesis. Presentations from Dennis McGonagle (Leeds, UK), Richard Hodgson (Leeds, UK), and Paolo Gisondi (Verona, Italy) elaborated on this theme and prepared the meeting attendees for group discussions of further work in this area. Imaging, notably magnetic resonance imaging (MRI) and ultrasonography, provides evidence of pathological change at the enthesis in psoriatic arthritis (PsA). Further, imaging abnormalities are found at sites that are asymptomatic in both PsA and psoriasis. The role of newer imaging modalities, such as ultra-short echo time (UTE) MRI, is promising but remains to be fully elucidated. The implication of these findings in relation to subclinical and predisease status is intriguing and requires further study in longitudinal studies. Further work is also required to examine the proposed common biomechanical basis between joint and skin, the mechanism of the resulting inflammation, and how these mechanisms differ from those seen in rheumatoid arthritis.

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