scholarly journals Importance of complex blood flow in the assessment of aortic regurgitation severity using phase contrast magnetic resonance imaging

2021 ◽  
Author(s):  
Frida Truedsson ◽  
Christian L. Polte ◽  
Sinsia A. Gao ◽  
Åse A. Johnsson ◽  
Odd Bech-Hanssen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Aortic Regurgitation ◽  
Phase Contrast ◽  
Flow Volume ◽  
Resonance Imaging ◽  
Complex Flow ◽  
Phase Contrast Mri ◽  
Sinotubular Junction ◽  
Contrast Magnetic Resonance

AbstractThis study aimed to investigate if and how complex flow influences the assessment of aortic regurgitation (AR) using phase contrast MRI in patients with chronic AR. Patients with moderate (n = 15) and severe (n = 28) chronic AR were categorized into non-complex flow (NCF) or complex flow (CF) based on the presence of systolic backward flow volume. Phase contrast MRI was performed repeatedly at the level of the sinotubular junction (Ao1) and 1 cm distal to the sinotubular junction (Ao2). All AR patients were assessed to have non-severe AR or severe AR (cut-off values: regurgitation volume (RVol) ≥ 60 ml and regurgitation fraction (RF) ≥ 50%) in both measurement positions. The repeatability was significantly lower, i.e. variation was larger, for patients with CF than for NCF (≥ 12 ± 12% versus ≥ 6 ± 4%, P ≤ 0.03). For patients with CF, the repeatability was significantly lower at Ao2 compared to Ao1 (≥ 21 ± 20% versus ≥ 12 ± 12%, P ≤ 0.02), as well as the assessment of regurgitation (RVol: 42 ± 34 ml versus 54 ± 42 ml, P < 0.001; RF: 30 ± 18% versus 34 ± 16%, P = 0.01). This was not the case for patients with NCF. The frequency of patients that changed in AR grade from severe to non-severe when the position of the measurement changed from Ao1 to Ao2 was higher for patients with CF compared to NCF (RVol: 5/26 (19%) versus 1/17 (6%), P = 0.2; RF: 4/26 (15%) versus 0/17 (0%), P = 0.09). Our study shows that complex flow influences the quantification of chronic AR, which can lead to underestimation of AR severity when using PC-MRI.

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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