Individualized arterial spin labeling background suppression by rapid T1 mapping during acquisition

T Lindner,H Guerreiro,F Austein,J Fiehler

doi:10.1007/s00330-022-08550-8

T Lindner, H Guerreiro + Show 2 more

Open Access

https://doi.org/10.1007/s00330-022-08550-8

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Abstract

ObjectiveArterial spin labeling blood perfusion signal relies on the difference between a label and a control image. Background suppression pulses are commonly used to improve the contrast, yet these are based on estimates of tissue relaxation times. The aim of this study is to improve the perfusion contrast by individualizing the timing of these background suppression pulses by means of T1 mapping.MethodsThe optimized timing of the background suppression pulses is obtained by rapid T1 mapping employing the variable flip angle technique. Ten healthy volunteers were included in this study. To compare the results, visual grading and the Wilcoxon signed-rank test was used comparing three categories of image quality.ResultsThe readers confirmed that the images of the proposed method generally show a higher signal-to-background ratio and cortical structures are better visible. Noise was mostly comparable to the standard method. Relative blood flow was statistically significant higher in the modified method.ConclusionThe individually optimized background suppression pulses improve the image appearance and allow for a better visualization of cortical structures. The proposed technique however prolongs scan time, which can be seen as negative result, yet needs to be further evaluated.Key Points• Background suppression timing in ASL can vary.• Both the label and control condition can be modified for T1 mapping.• Adapting the pulse timing improves the signal-to-background ratio.

Highlights

The readers confirmed that the images of the proposed method generally show a higher signal-to-background ratio and cortical structures are better visible
The proposed technique prolongs scan time, which can be seen as negative result, yet needs to be further evaluated
Arterial spin labeling (ASL) is a known method for non-contrastenhanced perfusion imaging mainly used in the brain and offers possibilities to obtain reliable information about underlying pathologies that influence perfusion [1]

Summary

Introduction

Arterial spin labeling (ASL) is a known method for non-contrastenhanced perfusion imaging mainly used in the brain and offers possibilities to obtain reliable information about underlying pathologies that influence perfusion [1]. Eur Radiol used which aim for increasing the signal difference between blood perfusion signal and static tissue [1,2,3] These are inversion pulses timed in a sense that at the time of image acquisition brain tissue (gray and white matter and cerebrospinal fluid) is being maximally suppressed while blood signal is at maximum. This process is performed either empirically or by using optimization algorithms [4]. A method was presented that calculated the T1 values from the

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Conclusion