Work

Quantitative ultrashort T2 components imaging in the brain using variable flip angle balanced steady state free precession ultrashort echo time MRI

Year: 2025

Type: article

Abstract: • Novel method for quantifying ultrashort T2 components in the brain • Balanced steady-state free precession ultrashort echo time MRI sequence was used • High efficiency sequence enabled high-resolution images and maps • Ultrashort-T2 component quantifications showed reasonable consistency between separate scans • Ultrashort-T2 component maps showed signal loss in multiple sclerosis patients’ lesions which are characterized by demyelination This study aimed to develop a new method for quantitative measurement of ultrashort T 2 (uT 2 ) components in the brain that are associated with myelin, providing reliable and high-quality fitting results of uT 2 fraction. Four healthy volunteers and four multiple sclerosis (MS) patients were recruited. A modified dual-echo balanced steady state free precession (bSSFP) ultrashort echo time (UTE) sequence was applied for acquisitions at six flip angles. The signals originating from uT 2 components (e.g., myelin) were extracted and fitted by analyzing the differences between TE 1 = 50 μ s and TE 2 = 2.2 ms signal curves along flip angles. A two-sample t-test was used for statistical comparison between uT 2 fractions in white matter (WM), gray matter (GM), and MS lesions. The differences between two TEs’ signal curves along flip angles showed clear evidence of a uT 2 component with a shape that matched the simulated results. Significantly higher uT 2 fraction values were found in total WM than total GM for all individuals (around 6%-7% vs. 2%, P <0.001). In healthy volunteers, the uT 2 fraction was consistent between repeated scans. In addition, the uT 2 fraction in MS lesions was quantified with significantly reduced values than surrounding normal appearing WM by this method (4.84% ± 0.49% vs. 7.96% ± 0.94%, P <0.001). An isotropic sub-millimeter resolution uT 2 fraction map was achieved with a simplified fitting model, and corresponded to expected patterns of myelination. There was a significant uT 2 fraction reduction in MS patients’ lesions. The repeatability of the quantification was verified by the consistency between two separate scans.

Source: NeuroImage

DOI: 10.1016/j.neuroimage.2025.121551

Authors: Xin Shen, Ari Green, Roland G. Henry, Nikhil Deveshwar, Uzay Emir, Peder E.Z. Larson

Institutions: University of California, San Francisco, University of North Carolina at Chapel Hill

Language: English

Topic: Advanced MRI Techniques and Applications

Subfield: Radiology, Nuclear Medicine and Imaging

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,540