scholarly journals Comparison of hemodialysis arteriovenous fistula blood flow rates measured by Doppler ultrasound and phase-contrast magnetic resonance imaging

2018 ◽  
Vol 68 (6) ◽  
pp. 1848-1857.e2 ◽  
Author(s):  
Yong He ◽  
Yan-Ting Shiu ◽  
Daniel B. Pike ◽  
Prabir Roy-Chaudhury ◽  
Alfred K. Cheung ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Arteriovenous Fistula ◽  
Doppler Ultrasound ◽  
Phase Contrast ◽  
Resonance Imaging ◽  
Flow Rates ◽  
Contrast Magnetic Resonance ◽  
Hemodialysis Arteriovenous Fistula

scholarly journals Aging Effects on Cerebral Blood and Cerebrospinal Fluid Flows

2007 ◽  
Vol 27 (9) ◽  
pp. 1563-1572 ◽  
Author(s):  
Souraya Stoquart-ElSankari ◽  
Olivier Balédent ◽  
Catherine Gondry-Jouet ◽  
Malek Makki ◽  
Olivier Godefroy ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
The Elderly ◽  
Elderly Group ◽  
Resonance Imaging ◽  
Aging Effects ◽  
Contrast Magnetic Resonance

Phase-contrast magnetic resonance imaging (PC-MRI) is a noninvasive reliable technique, which enables quantification of cerebrospinal fluid (CSF) and total cerebral blood flows (tCBF). Although it is used to study hydrodynamic cerebral disorders in the elderly group (hydrocephalus), there is no published evaluation of aging effects on both tCBF and CSF flows, and on their mechanical coupling. Nineteen young (mean age 27 ± 4 years) and 12 elderly (71 ± 9 years) healthy volunteers underwent cerebral MRI using 1.5 T scanner. Phase-contrast magnetic resonance imaging pulse sequence was performed at the aqueductal and cervical levels. Cerebrospinal fluid and blood flow curves were then calculated over the cardiac cycle, to extract the characteristic parameters: mean and peak flows, their latencies, and stroke volumes for CSF (cervical and aqueductal) and vascular flows. Total cerebral blood flow was ( P < 0.01) decreased significantly in the elderly group when compared with the young subjects with a linear correlation with age observed only in the elderly group ( R2 = 0.7; P = 0.05). Arteriovenous delay was preserved with aging. The CSF stroke volumes were significantly reduced in the elderly, at both aqueductal ( P < 0.01) and cervical ( P < 0.05) levels, whereas aqueduct/cervical proportion ( P = 0.9) was preserved. This is the first work to study aging effects on both CSF and vascular cerebral flows. Data showed (1) tCBF decrease, (2) proportional aqueductal and cervical CSF pulsations reduction as a result of arterial loss of pulsatility, and (3) preserved intracerebral compliance with aging. These results should be used as reference values, to help understand the pathophysiology of degenerative dementia and cerebral hydrodynamic disorders as hydrocephalus.

scholarly journals Phase-contrast magnetic resonance imaging to assess renal perfusion: a systematic review and statement paper

2019 ◽  
Vol 33 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Giulia Villa ◽  
Steffen Ringgaard ◽  
Ingo Hermann ◽  
Rebecca Noble ◽  
Paolo Brambilla ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Systematic Review ◽  
Blood Flow ◽  
Clinical Practice ◽  
Magnetic Resonance ◽  
Kidney Disease ◽  
Phase Contrast ◽  
Resonance Imaging ◽  
Non Invasive ◽  
Contrast Magnetic Resonance

Abstract Objective Phase-contrast magnetic resonance imaging (PC-MRI) is a non-invasive method used to compute blood flow velocity and volume. This systematic review aims to discuss the current status of renal PC-MRI and provide practical recommendations which could inform future clinical studies and its adoption in clinical practice. Methodology A comprehensive search of all the PC-MRI studies in human healthy subjects or patients related to the kidneys was performed. Results A total of 39 studies were included in which PC-MRI was used to measure renal blood flow (RBF) alongside other derivative hemodynamic parameters. PC-MRI generally showed good correlation with gold standard methods of RBF measurement, both in vitro and in vivo, and good reproducibility. Despite PC-MRI not being routinely used in clinical practice, there are several clinical studies showing its potential to support diagnosis and monitoring of renal diseases, in particular renovascular disease, chronic kidney disease and autosomal dominant polycystic kidney disease. Discussion Renal PC-MRI shows promise as a non-invasive technique to reliably measure RBF, both in healthy volunteers and in patients with renal disease. Future multicentric studies are needed to provide definitive normative ranges and to demonstrate the clinical potential of PC-MRI, likely as part of a multi-parametric renal MRI protocol.

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