scholarly journals Application of Arterial Spin Labelling in Detecting Retinal Ischemia

2017 ◽  
Vol 8 (3) ◽  
pp. 545-557 ◽  
Author(s):  
Ehsan Vaghefi ◽  
Kevin Kauv ◽  
Wilson Pan ◽  
David Squirrell
Keyword(s):  
Normal Values ◽  
Blood Perfusion ◽  
Retinal Ischemia ◽  
Motion Artifacts ◽  
Arterial Spin Labelling ◽  
Arterial Flow ◽  
Tissue Volume ◽  
Filling Time ◽  
Anatomical Mri ◽  
Spin Labelling

Purpose: Here, we have tried to quantify the chorioretinal blood perfusion in patients who are clinically identified to be suffering from retinal ischemia using arterial spin labelling (ASL) MRI. Method: Four participants, diagnosed with retinal ischemia based on their structural OCT and angiography test, were then scanned using anatomical MRI as well as ASL. We optimized MR parameters to maximize resolution and target fixation, blinking, and breathing ques to minimize motion artifacts. Results: Participants had a maximum of ∼50 mL/100 mL/min of blood perfusion, which is below the normal values of ∼200 mL/100 mL/min. It also appeared that thinning of the choroid contributes more to the measured decreased chorioretinal perfusion, compared to slowed arterial filling time. Conclusion: Decreased chorioretinal perfusion is a multifactorial event and has been implicated in several posterior eye pathologies. Based on our current results, it seems that ischemia of the eye could be due to anatomy (tissue volume) and/or functionality (arterial flow).

scholarly journals Mild cognitive impairment with Lewy bodies: blood perfusion with arterial spin labelling

2020 ◽  
Author(s):  
Michael J. Firbank ◽  
John T. O’Brien ◽  
Rory Durcan ◽  
Louise M. Allan ◽  
Sally Barker ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Lewy Bodies ◽  
Region Of Interest ◽  
Blood Perfusion ◽  
Arterial Spin Labelling ◽  
Posterior Cingulate ◽  
Eyes Closed ◽  
Eyes Open ◽  
Spin Labelling

Abstract Objective To use arterial spin labelling to investigate differences in perfusion in mild cognitive impairment with Lewy bodies (MCI-LB) compared to Alzheimer type MCI (MCI-AD) and healthy controls. Methods We obtained perfusion images on 32 MCI-LB, 30 MCI-AD and 28 healthy subjects of similar age. Perfusion relative to cerebellum was calculated, and we aimed to examine differences in relative perfusion between MCI-LB and the other groups. This included whole brain voxelwise comparisons, as well as using predefined region-of-interest ratios of medial occipital to medial temporal, and posterior cingulate to precuneus. Differences in occipital perfusion in eyes open vs eyes closed conditions were also examined. Results Compared to controls, the MCI-LB showed reduced perfusion in the precuneus, parietal, occipital and fusiform gyrus regions. In our predefined regions, the ratio of perfusion in occipital/medial temporal was significantly lower, and the posterior cingulate/precuneus ratio was significantly higher in MCI-LB compared to controls. Overall, the occipital perfusion was greater in the eyes open vs closed condition, but this did not differ between groups. Conclusion We found patterns of altered perfusion in MCI-LB which are similar to those seen in dementia with Lewy bodies, with reduction in posterior parietal and occipital regions, but relatively preserved posterior cingulate.

scholarly journals Application of Arterial Spin Labelling in the Assessment of Ocular Tissues

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
E. Vaghefi ◽  
B. Pontré
Keyword(s):  
Blood Flow ◽  
Mr Imaging ◽  
Quantitative Methods ◽  
Blood Perfusion ◽  
Arterial Spin Labelling ◽  
The Body ◽  
Ocular Tissue ◽  
Ocular Tissues ◽  
Retinal Pathologies ◽  
Spin Labelling

Arterial spin labelling (ASL) is a noninvasive magnetic resonance imaging (MRI) modality, capable of measuring blood perfusion without the use of a contrast agent. While ASL implementation for imaging the brain and monitoring cerebral blood flow has been reviewed in depth, the technique is yet to be widely used for ocular tissue imaging. The human retina is a very thin but highly stratified structure and it is also situated close to the surface of the body which is not ideal for MR imaging. Hence, the application of MR imaging and ASL in particular has been very challenging for ocular tissues and retina. That is despite the fact that almost all of retinal pathologies are accompanied by blood perfusion irregularities. In this review article, we have focused on the technical aspects of the ASL and their implications for its optimum adaptation for retinal blood perfusion monitoring. Retinal blood perfusion has been assessed through qualitative or invasive quantitative methods but the prospect of imaging flow using ASL would increase monitoring and assessment of retinal pathologies. The review provides details of ASL application in human ocular blood flow assessment.

scholarly journals Advanced magnetic resonance imaging of cortical laminar necrosis in patients with stroke

2019 ◽  
Vol 32 (6) ◽  
pp. 431-437 ◽  
Author(s):  
Roberto Cannella ◽  
Gianvincenzo Sparacia ◽  
Vincenzina Lo Re ◽  
Elisa Oddo ◽  
Giuseppe Mamone ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Acute Stage ◽  
Arterial Spin Labelling ◽  
Resonance Imaging ◽  
Cortical Laminar Necrosis ◽  
Diffusion Weighted ◽  
Cortical Laminar ◽  
Laminar Necrosis ◽  
Spin Labelling

Purpose The aim of this study was to assess the novel advanced magnetic resonance imaging findings of acute stage cortical laminar necrosis developing after complicated cardiovascular or abdominal surgery. Materials and methods This institutional review board-approved study included patients with postoperative stroke due to cortical laminar necrosis imaged with magnetic resonance in the acute stage. Brain magnetic resonance imaging examinations were obtained on a 3T magnetic resonance scanner within 48 hours of the neurological symptoms, including diffusion-weighted images (b value, 1000 s/mm2) and arterial spin labelling using a pseudo-continuous arterial spin labelling method in four patients. Conventional and advanced magnetic resonance images were analysed to assess the imaging features in acute stage cortical laminar necrosis. Results The final population consisted of 14 patients (seven men and seven women, mean age 61 years, range 32–79 years) diagnosed with stroke and acute phase cortical laminar necrosis. All the patients presented with cortical lesions showing restricted diffusion on diffusion-weighted images and hypointensity on the apparent diffusion coefficient map. Cortical hyperintensity on T2-weighted or fluid-attenuated inversion recovery images was found in three (21%) and six (43%) patients, respectively. Reduced perfusion was noted in three out of four patients imaged with arterial spin labelling, while in one case no corresponding perfusion abnormality was noted on the arterial spin labelling maps. Arterial spin labelling abnormalities were much more extensive than diffusion restriction in two patients, and they were associated with a poor outcome. Conclusion Cortical hyperintense abnormalities on diffusion-weighted imaging may be the only sign of developing cortical laminar necrosis injury. The acquisition of arterial spin labelling helps to identify perfusion alterations and the extension of the ischaemic injury.

Repeatability of perfusion measurements in adult gliomas using pulsed and pseudo-continuous arterial spin labelling MRI

2021 ◽  
Author(s):  
Amirah Faisal Alsaedi ◽  
David Lee Thomas ◽  
Enrico De Vita ◽  
Jasmina Panovska-Griffiths ◽  
Sotirios Bisdas ◽  
...  
Keyword(s):  
Arterial Spin Labelling ◽  
Perfusion Measurements ◽  
Spin Labelling
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