Rapid whole-brain quantitative MT imaging

IF 2.4 4区医学 Q2 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Zeitschrift fur Medizinische Physik Pub Date : 2025-02-01 DOI:10.1016/j.zemedi.2023.02.005

Roya Afshari , Francesco Santini , Rahel Heule , Craig H. Meyer , Josef Pfeuffer , Oliver Bieri

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引用次数: 0

Abstract

Purpose

To provide a robust whole-brain quantitative magnetization transfer (MT) imaging method that is not limited by long acquisition times.

Methods

Two variants of a spiral 2D interleaved multi-slice spoiled gradient echo (SPGR) sequence are used for rapid quantitative MT imaging of the brain at 3 T. A dual flip angle, steady-state prepared, double-contrast method is used for combined B₁ and-T₁ mapping in combination with a single-contrast MT-prepared acquisition over a range of different saturation flip angles (50 deg to 850 deg) and offset frequencies (1 kHz and 10 kHz). Five sets (containing minimum 6 to maximum 18 scans) with different MT-weightings were acquired. In addition, main magnetic field inhomogeneities (ΔB₀) were measured from two Cartesian low-resolution 2D SPGR scans with different echo times. Quantitative MT model parameters were derived from all sets using a two-pool continuous-wave model analysis, yielding the pool-size ratio, F, their exchange rate, k_f, and their transverse relaxation time, T_2r.

Results

Whole-brain quantitative MT imaging was feasible for all sets with total acquisition times ranging from 7:15 min down to 3:15 min. For accurate modeling, B₁-correction was essential for all investigated sets, whereas ΔB₀-correction showed limited bias for the observed maximum off-resonances at 3 T.

Conclusion

The combination of rapid B₁-T₁ mapping and MT-weighted imaging using a 2D multi-slice spiral SPGR research sequence offers excellent prospects for rapid whole-brain quantitative MT imaging in the clinical setting.

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快速全脑定量MT成像。

目的:提供一种不受长采集时间限制的可靠的全脑定量磁化转移(MT)成像方法。方法:采用两种螺旋二维交错多层失稳梯度回波(SPGR)序列，在3 t时对大脑进行快速定量MT成像。采用双翻转角度、稳态制备的双对比度方法，结合在不同饱和翻转角度(50°至850°)和偏移频率(1 kHz和10 kHz)范围内的单对比度MT制备采集，进行B1和t1组合成像。获得了5组不同mt权重的扫描(包含最少6到最多18次扫描)。此外，通过两次不同回波时间的笛卡尔低分辨率二维SPGR扫描测量了主磁场不均匀性(ΔB0)。使用双池连续波模型分析从所有集合中获得定量MT模型参数，得到池大小比F、它们的汇率kf和它们的横向弛豫时间T2r。结果:全脑定量MT成像对所有集都是可行的，总采集时间从7:15分钟到3:15分钟不等。为了准确建模，b1校正对所有研究集都是必不可少的，而ΔB0-correction对观察到的最大非共振在3t时显示有限的偏差。快速B1-T1定位与二维多层螺旋SPGR研究序列的MT加权成像相结合，为临床快速全脑定量MT成像提供了良好的前景。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Zeitschrift fur Medizinische Physik 医学-核医学

CiteScore

3.70

自引率

10.00%

发文量

审稿时长

65 days

期刊介绍： Zeitschrift fur Medizinische Physik (Journal of Medical Physics) is an official organ of the German and Austrian Society of Medical Physic and the Swiss Society of Radiobiology and Medical Physics.The Journal is a platform for basic research and practical applications of physical procedures in medical diagnostics and therapy. The articles are reviewed following international standards of peer reviewing. Focuses of the articles are: -Biophysical methods in radiation therapy and nuclear medicine -Dosimetry and radiation protection -Radiological diagnostics and quality assurance -Modern imaging techniques, such as computed tomography, magnetic resonance imaging, positron emission tomography -Ultrasonography diagnostics, application of laser and UV rays -Electronic processing of biosignals -Artificial intelligence and machine learning in medical physics In the Journal, the latest scientific insights find their expression in the form of original articles, reviews, technical communications, and information for the clinical practice.