Understanding and optimizing the amplitude modulated control for multiple‐slice continuous arterial spin labeling

Utting, Jane F.; Thomas, David L.; Gadian, David G.; Helliar, Robert W.; Lythgoe, Mark F.; Ordidge, Roger J.

doi:10.1002/mrm.20604

Cited by 14 publications

(25 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We used a representative T 1sat of 0.86 seconds, similar to that used by Utting et al (2005). The pH-weighted image was derived as CEST ratio asymmetry (CESTR asym ), which calculates the difference between label and reference images, normalized by the control scan (I 0 ) per voxel as ( CESTR asym ¼ ðI ref À I label Þ=I 0 ).…”

Section: Data Processingmentioning

confidence: 99%

Association between pH-Weighted Endogenous Amide Proton Chemical Exchange Saturation Transfer MRI and Tissue Lactic Acidosis during Acute Ischemic Stroke

Sun

Cheung

Wang

et al. 2011

J Cereb Blood Flow Metab

129

139

View full text Add to dashboard Cite

The ischemic tissue becomes acidic after initiation of anaerobic respiration, which may result in impaired tissue metabolism and, ultimately, in severe tissue damage. Although changes in the major cerebral metabolites can be studied using magnetic resonance (MR) spectroscopy (MRS)-based techniques, their spatiotemporal resolution is often not sufficient for routine examination of fastevolving and heterogeneous acute stroke lesions. Recently, pH-weighted MR imaging (MRI) has been proposed as a means to assess tissue acidosis by probing the pH-dependent chemical exchange of amide protons from endogenous proteins and peptides. In this study, we characterized acute ischemic tissue damage using localized proton MRS and multiparametric imaging techniques that included perfusion, diffusion, pH, and relaxation MRI. Our study showed that pH-weighted MRI can detect ischemic lesions and strongly correlates with tissue lactate content measured by 1 H MRS, indicating lactic acidosis. Our results also confirmed the correlation between apparent diffusion coefficient and lactate; however, no significant relationship was found for perfusion, T 1 , and T 2 . In summary, our study showed that optimized endogenous pH-weighted MRI, by sensitizing to local tissue pH, remains a promising tool for providing a surrogate imaging marker of lactic acidosis and altered tissue metabolism, and augments conventional techniques for stroke diagnosis.

show abstract

Section: Data Processingmentioning

confidence: 99%

Association between pH-Weighted Endogenous Amide Proton Chemical Exchange Saturation Transfer MRI and Tissue Lactic Acidosis during Acute Ischemic Stroke

Sun

Cheung

Wang

et al. 2011

J Cereb Blood Flow Metab

129

139

View full text Add to dashboard Cite

show abstract

“…18 Vascular and fat-suppression modules were also used with a labeling pulse duration of 3 seconds. Postlabeling delay and the gap between the labeling plane and the central imaging plane were 300 and 20 mm, respectively.…”

Section: Mr Imaging Acquisitionmentioning

confidence: 99%

“…The rest of the sequence parameters were identical to those used for pseudocontinuous ASL data acquisition. 18 The typical total scan time of ASL was ϳ10 minutes.…”

Section: Mr Imaging Acquisitionmentioning

confidence: 99%

“…CBF maps were derived according to previous reports. 18,19 A 3-parameter fit was used for estimating T1 maps. Once T1 maps and control and labeled images were obtained, tissue blood flow images were formed according to the following formula: CBF ϭ ( / T1) ϫ (S control Ϫ S label ) / (2␣ ϫ S control ), where ϭ 0.9 was the tissue/blood partition coefficient for water, 19 S control was the control image signal intensity, S label was the labeled image signal intensity, T1 was the T1 map, and ␣ was 0.63 as the degree of labeling efficiency.…”

Section: Mr Imaging Data Analysismentioning

confidence: 99%

“…Once T1 maps and control and labeled images were obtained, tissue blood flow images were formed according to the following formula: CBF ϭ ( / T1) ϫ (S control Ϫ S label ) / (2␣ ϫ S control ), where ϭ 0.9 was the tissue/blood partition coefficient for water, 19 S control was the control image signal intensity, S label was the labeled image signal intensity, T1 was the T1 map, and ␣ was 0.63 as the degree of labeling efficiency. 18 For DSC perfusion MR imaging, additional preprocessing was performed by using commercial software (nordicICE; NordicNeuroLab, Bergen, Norway), in which T2WIs were used for structural imaging. rCBV maps were generated by using established tracer kinetic models applied to first-pass data.…”

Section: Mr Imaging Data Analysismentioning

confidence: 99%

See 2 more Smart Citations

Antiangiogenic Effect of Bevacizumab: Application of Arterial Spin-Labeling Perfusion MR Imaging in a Rat Glioblastoma Model

Tie

Cho

Choi

et al. 2016

AJNR Am J Neuroradiol

View full text Add to dashboard Cite

show abstract

Improved pseudo‐continuous arterial spin labeling for mapping brain perfusion

Nezamzadeh

Matson

Young

et al. 2010

Magnetic Resonance Imaging

View full text Add to dashboard Cite

Purpose To investigate arterial spin labeling (ASL) methods for improved brain perfusion mapping. Previously, Pseudo-continuous arterial spin labeling (pCASL) was developed to overcome limitations inherent with conventional continuous arterial spin labeling (CASL), but the control scan (null pulse) in the original method for pCASL perturbs the equilibrium magnetization, diminishing the ASL signal. Here, a new modification of pCASL, termed mpCASL is reported, in which the perturbation caused by the null pulse is reduced and perfusion mapping improved. Materials and Methods Improvements with mpCASL are demonstrated using numerical simulations and experiments. ASL signal intensity as well as contrast and reproducibility of in-vivo brain perfusion images were measured in four volunteers who had MRI scans at 4 Tesla and the data compared across the labeling methods. Results Perfusion maps with mpCASL showed, on average, higher ASL signal intensity and higher image contrast than those from CASL or pCASL. Furthermore, mpCASL yielded better reproducibility in repeat scans than the other methods. Conclusion The experimental results are consistent with the hypothesis that the new null pulse of mpCASL leads to improved brain perfusion images.

show abstract

Understanding and optimizing the amplitude modulated control for multiple‐slice continuous arterial spin labeling

Cited by 14 publications

References 33 publications

Association between pH-Weighted Endogenous Amide Proton Chemical Exchange Saturation Transfer MRI and Tissue Lactic Acidosis during Acute Ischemic Stroke

Association between pH-Weighted Endogenous Amide Proton Chemical Exchange Saturation Transfer MRI and Tissue Lactic Acidosis during Acute Ischemic Stroke

Antiangiogenic Effect of Bevacizumab: Application of Arterial Spin-Labeling Perfusion MR Imaging in a Rat Glioblastoma Model

Improved pseudo‐continuous arterial spin labeling for mapping brain perfusion

Contact Info

Product

Resources

About