Applications of arterial spin labeled MRI in the brain

Abstract

Perfusion provides oxygen and nutrients to tissues and is closely tied to tissue function, and disorders of perfusion are major sources of medical morbidity and mortality. It has been almost two decades since the use of arterial spin labeling (ASL) for noninvasive perfusion imaging was first reported. While initial ASL MRI studies focused primarily on technological development and validation, a number of robust ASL implementations have emerged, and ASL MRI is now also available commercially on several platforms. As a result, basic science and clinical applications of ASL MRI have begun to proliferate. Although ASL MRI can be carried out in any organ, most studies to date have focused on the brain. This review covers selected research and clinical applications of ASL MRI in the brain to illustrate is potential in both neuroscience research and clinical care.

Correlation of 3D Arterial Spin Labeling and Multi-Parametric Dynamic Susceptibility Contrast Perfusion MRI in Brain Tumors

“…(15,16). Similarly, Tmax parameter derived from DSC could be strongly affected by tracer arrival delay, unlike in deconvolution methods (9,10).…”

“…The disadvantages of ASL, compared with DSC MRI, are transit time sensitivity, lower SNR and longer acquisition time. However, ASL perfusion imaging was recently improved with higher SNR, lower artifacts, and 3D imaging with background suppression (15,16).…”

“…ASL is non-invasive and uses magnetically labeled proton in the arterial blood water as an endogenous tracer to quantify CBF (14). ASL perfusion imaging has been continuously improving with three -dimensional (3D) imaging and background suppression, higher signal-to-noise ratio (SNR), and low artifacts (15,16). It would be a desirable perfusion method without the use of exogenous contrast agent ; however, the utility of ASL has been challenging in clinical practice due to transit time effect (17,18).…”

Measuring Biexponential Transverse Relaxation of the ASL Signal at 9.4 T to Estimate Arterial Oxygen Saturation and the Time of Exchange of Labeled Blood Water into Cortical Brain Tissue

“…Recent hardware improvements and sequence innovations have helped ASL to become an increasingly important and widely used tool in both clinical and research settings. 4,5 Flow sensitive alternating inversion recovery (FAIR) is a pulsed ASL (PASL) technique in which pairs of images are acquired after global and slice-selective inversion pulses. 6,7 The time between labeling and image acquisition is known as the inflow time (TI).…”

Discrimination and anatomical mapping of PET-positive lesions: comparison of CT attenuation-corrected PET images with coregistered MR and CT images in the abdomen

“…Integrated PET/MR opens new perspectives in biomedical research and clinical multimodality imaging [3][4][5][6]. In addition to better soft tissue contrast and lack of ionizing radiation exposure, MRI offers a wide range of advanced imaging techniques [7,8], such as apparent diffusion coefficient maps for quantification of cellular density [9], arterial spin labelling for measurement of blood flow [10], dynamic contrast enhancement to assess the characteristics of tumour vasculature, including perfusion, blood vessel permeability, blood volume and extravascular extracellular volume fraction [11], and quantification of tissue metabolite concentrations by calibrated 1 H-MR spectroscopy [12,13] or based on hyperpolarized 13 C [14]. Hence, multiparametric PET/MR has the potential to become a powerful tool for accurate primary diagnosis and early evaluation of therapy response.…”