scholarly journals Fold-Over Oversampling Effects in the Measurements of Cerebral Cerebrospinal Fluid and Blood Flows with 2D Cine Phase-Contrast MRI

Diagnostics ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 387
Author(s):  
Fadoua Saadani-Makki ◽  
Serge Metanbou ◽  
Garance Arbeaumont-Trocme ◽  
Julien Van Gysel ◽  
Malek I. Makki
Keyword(s):  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Stroke Volume ◽  
Phase Contrast ◽  
Blood Flows ◽  
Phase Offset ◽  
Section Area ◽  
Significant Difference ◽  
Before And After ◽  
Cine Phase Contrast

This prospective study investigated the effects of fold-over oversampling on phase-offset background errors with 2D-Cine phase contrast (Cine-PC) magnetic resonance imaging (MRI). It was performed on brain MRI and compared to conventional Full-field of view FOV coverage and it was tested with two different velocity encoding (Venc) values. We chose Venc = 100 mm/s to encode cerebrospinal fluid (CSF) flows in the aqueduct and 600 mm/s to encode blood flow in the carotid artery. Cine-PC was carried out on 10 healthy adult volunteers followed simultaneously by an acquisition on static agar-gel phantom to measure the phase-offset background errors. Pixel-wise correction of both the CSF and the blood flows was calculated through 32 points of the cardiac-cycle. We compared the velocity-to-noise ratio, the section area, the absolute and the corrected velocity (peak; mean and minimum), the net flow, and the stroke volume before and after correction. We performed the statistical T-test to compare Full-FOV and fold-over and Bland–Altman plots to analyze their differences. Our results showed that following phase-offset error correction, the blood stroke-volume was significantly higher with Full-FOV compared to fold-over. We observed a significantly higher CSF mean velocity and net flow values in the fold-over option. Compared to Full-FOV, fold-over provides a significantly larger section area and significantly lower peak velocity-offset in the aqueduct. No significant difference between the two coverages was reported before and after phase-offset in blood flow measurements. In conclusion, fold-over oversampling can be chosen as an alternative to increase spatial resolution and accurate cerebral flow quantification in Cine-PC.

scholarly journals Phase-Contrast MRI Indices can Reflect Intracranial Compliance Deterioration Induced by Intra-Abdominal/ Thoracic Hypertension

2021 ◽  
Author(s):  
Jie Feng ◽  
Xiao Yu ◽  
Jie Liu ◽  
Wenjia Liu ◽  
Lin Ma
Keyword(s):  
Blood Flow ◽  
Phase Contrast ◽  
Trauma Patients ◽  
Phase Contrast Mri ◽  
Time To Peak ◽  
Intracranial Compliance ◽  
Cross Section Area ◽  
Section Area ◽  
Abdominal Hypertension ◽  
Cine Phase Contrast

Abstract BackgroundIdentifying elevated intracranial pressure (ICP) and decreased intracranial compliance (ICC) is imperative for optimizing patient management in neurocritical care settings. Intra-abdominal hypertension (IAH) and intrathoracic hypertension (ITH) is common in trauma patients, which affects homeostasis of ICP/ICC. Knowledge of this effects is little and monitoring this effect is difficult. In the current study, we examined whether the indices generated from 2D cine phase contrast MRI (2D cine PC-MRI) could reflect ICC/ICP alterations induced by elevated IAH/ITH during VM.MethodsA total of 50 healthy young volunteers participated in this study (male: female = 24:26), and took a 2D cine PC-MRI during normal breath and VM respectively. Cross-section area (CSA) of dominant IJV and ipsilateral ICA, the maximum blood flow (Fmax), minimum blood flow (Fmin), mean blood flow (MBF), pulsatility index (PI), arteriovenous delay (AVD) and time to peak of arterial pulse (TTP) were gauged from images or calculated from the blood flow curves generated from 2D cine PC-MRI. ResultsDuring VM state, in comparison to NB, CSAIJV increased significantly (p<0.0001), indicating an elevation of cerebral venous outflow resistance; Fmax_ICA, Fmax_IJV, Fmean_ICA and Fmean_IJV decreased significantly (p<0.0001, p<0.0001, p<0.001, p<0.0001, respectively); PI_ICA and PI_IJV decreased significantly (p<0.0001, p<0.0001); both absolute and normalized AVD decreased significantly (p<0.0001, p<0.0001), while absolute and normalized TTP increased significantly (p=0.0329, p=0.0376).Conclusions Indices generated from 2D cine PC-MRI, especially AVD and TTP, can reveal the ICC/ICP dynamics induced by elevated IAP/ITP. These indices have potential clinical application in ICC/ICP monitoring in patients who was speculated with an IAH or ITH.

scholarly journals Hodge decomposition of wall shear stress vector fields characterizing biological flows

2019 ◽  
Vol 6 (2) ◽  
pp. 181970 ◽  
Author(s):  
Faniry H. Razafindrazaka ◽  
Pavlo Yevtushenko ◽  
Konstantin Poelke ◽  
Konrad Polthier ◽  
Leonid Goubergrits
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Vector Fields ◽  
Coarctation Of The Aorta ◽  
Hodge Decomposition ◽  
Blood Flows ◽  
Significant Difference ◽  
Before And After ◽  
Wall Shear

A discrete boundary-sensitive Hodge decomposition is proposed as a central tool for the analysis of wall shear stress (WSS) vector fields in aortic blood flows. The method is based on novel results for the smooth and discrete Hodge–Morrey–Friedrichs decomposition on manifolds with boundary and subdivides the WSS vector field into five components: gradient (curl-free), co-gradient (divergence-free) and three harmonic fields induced from the boundary, which are called the centre, Neumann and Dirichlet fields. First, an analysis of WSS in several simulated simplified phantom geometries (duct and idealized aorta) was performed in order to understand the nature of the five components. It was shown that the decomposition is able to distinguish harmonic blood flow arising from the inlet from harmonic circulations induced by the interior topology of the geometry. Finally, a comparative analysis of 11 patients with coarctation of the aorta (CoA) before and after treatment as well as 10 control patients was done. The study shows a significant difference between the CoA patients before and after the treatment, and the healthy controls. This means a global difference between aortic shapes of diseased and healthy subjects, thus leading to a new type of WSS-based analysis and classification of pathological and physiological blood flow.

Evaluation of endorphin content in the CSF of patients with trigeminal neuralgia before and after Gasserian ganglion thermocoagulation

1981 ◽  
Vol 55 (6) ◽  
pp. 935-937 ◽  
Author(s):  
Giuseppe Salar ◽  
Salvatore Mingrino ◽  
Marco Trabucchi ◽  
Angelo Bosio ◽  
Carlo Semenza
Keyword(s):  
Cerebrospinal Fluid ◽  
Trigeminal Neuralgia ◽  
Control Group ◽  
Gasserian Ganglion ◽  
Content Type ◽  
Group Of Seven ◽  
Idiopathic Trigeminal Neuralgia ◽  
Significant Difference ◽  
Before And After ◽  
Fine Print

✓ The β-endorphin content in cerebrospinal fluid (CSF) was evaluated in 10 patients with idiopathic trigeminal neuralgia during medical treatment (with or without carbamazepine) and after selective thermocoagulation of the Gasserian ganglion. These values were compared with those obtained in a control group of seven patients without pain problems. No statistically significant difference was found between patients suffering from trigeminal neuralgia and those without pain. Furthermore, neither pharmacological treatment nor surgery changed CSF endorphin values. It is concluded that there is no pathogenetic relationship between trigeminal neuralgia and endorphins.

In Reply: Cerebral Blood Flow

PEDIATRICS ◽  
1982 ◽  
Vol 70 (6) ◽  
pp. 1013-1014
Author(s):  
RAUL BEJAR
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Gastrointestinal Tract ◽  
Ductus Arteriosus ◽  
Left Ventricular ◽  
Blood Flows ◽  
Before And After ◽  
Regional Blood Flows ◽  
Left Ventricular Output ◽  
Patent Ductus

Baylen and Emmanouilides give the impression that their abstract was misquoted in our commentary. We would like to explain our interpretation of their data. In the abstract, Baylen et al indicate that they measured regional blood flows (RBF) in premature fetal lambs, expressing them as a percentage of the left ventricular output (LVO) before and after patent ductus arteriosus (PDA) closure. Their results (percent of LVO) before and after PDA closure were: lung, 42.7% vs 8.4% (P &lt; .01); carcass, 35% vs 55% (P &lt; .01); heart, 5.5% vs 10.2% (P &lt; .05); gastrointestinal tract, 5.1% vs 9.3% (P &lt; .05); brain, 2.7% vs 3.4% (P = NS); kidney, 2.2% vs 3.3% (P = NS); liver, 3.2% vs 5.7% (P = NS).

P5280The impact of background phase offset errors in cardiovascular magnetic resonance phase contrast imaging: a multi-scanner study

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S C S Minderhoud ◽  
N Van Der Velde ◽  
J J Wentzel ◽  
M Attrach ◽  
P A Wielopolski ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Main Pulmonary Artery ◽  
Flow Quantification ◽  
Flow Measurements ◽  
Total N ◽  
Phase Offset ◽  
Wide Range ◽  
Significant Difference ◽  
Clinically Significant ◽  
The Impact

Abstract Background Phase contrast (PC) CMR flow measurements (FM) are widely used for blood flow assessment, but they suffer from phase offset errors (POE). Stationary phantom correction limits these inaccuracies, however, this adds scan time. Stationary tissue (ST) correction is an alternative method that does not require additional scanning. The aim of this study was to evaluate the impact of POE, to assess interscanner variation, and to evaluate the ST correction usage. Methods We included 166 patients in which both aorta and main pulmonary artery FM were acquired including static gelatin phantom data. Subjects were scanned on three types of 1.5T scanners from the one vendor. Uncorrected and ST corrected FM were compared with phantom corrected FM, our reference value, and corrected for BSA. A difference of >10% in net flow was defined as clinically relevant. Regurgitation fraction was calculated and POE influences were assessed. Regurgitation severity was graded and POE influence on severity grading was assessed. Results Of the 166 cases included, the median age was 27 (5–74) years. Overall, the median difference between no corrected and phantom corrected FM was ≤6%, however, with a wide range of over- and underestimation (−155%–78% change) (figure). ST correction resulted in larger differences compared to no correction (p<0.01). Clinically significant differences were seen in 19% of all FM with no correction and in 30% of with ST correction (p<0.01). Furthermore, there were significant differences between scanners (no correction 10%, p<0.01; ST correction, p<0.01). Regurgitation severity indexing changed in 38 (11%) cases with no correction and in 48 (48%) with ST correction. Magnitude of flow change with and without offset corrections (n=332) Flow (ml/m2) Δ no correction and phantom correction (%) Δ ST correction and phantom correction (%) Clinically significant difference (>10%) Mean ± SD Median IQR Range Median IQR Range No correction, N (%) ST correction , N (%) MRI 1 (n=126) 50±12 3 0 to 6 −8 to 30 5 −3 to 9 −26 to 28 13 (10%) 34 (27%) MRI 2 (n=102) 48±13 −2 −15 to 6 −155 to 78 5 −3 to 11 −74 to 52 50 (49%) 50 (49%) MRI 3 (n=104) 48±12 −1 −1 to 0 −7 to 14 2 −2 to 5 −39 to 29 1 (1%) 16 (15%) Total (n=332) 49±12 0 −2 to 4 −155 to 78 3 −2 to 8 −74 to 52 64 (19%) 100 (30%) Conclusion Background POE have a significant impact on flow quantification and regurgitation severity. Unexpectedly, background correction using ST correction worsens accuracy compared to no correction. POE vary greatly between scanners. Therefore, careful assessment of FM at each scanner is essential to determine if routine phantom scanning is necessary.

Hemodynamic effects of leukotriene C4 in ovine fetus

1990 ◽  
Vol 259 (6) ◽  
pp. E851-E855
Author(s):  
B. A. Meyer ◽  
S. W. Walsh ◽  
V. M. Parisi
Keyword(s):  
Blood Flow ◽  
Vena Cava ◽  
Cardiovascular Effects ◽  
In Vivo Studies ◽  
Leukotriene C4 ◽  
Blood Flows ◽  
Before And After ◽  
Placental Blood ◽  
Near Term

Leukotrienes are synthesized during pregnancy and produce cardiovascular effects in adults. We hypothesized that leukotriene C4 would cause vasoconstriction in the fetus and placenta. Eight near-term, unanesthetized ovine fetuses were studied before and after infusion of 10 micrograms leukotriene C4 (LTC4) into the fetal vena cava. Cardiovascular monitoring of maternal and fetal arterial pressures and heart rates was performed. Fetal blood flows were measured by the radioactive-microsphere technique. Sustained elevations in systolic and diastolic blood pressure and decreased fetal heart rate began by 1 min and returned to baseline by 30 min. Arterial pH fell from 7.33 +/- 0.01 to 7.29 +/- 0.01 at 15 min (P less than 0.05) and to 7.29 +/- 0.01 at 30 min (P less than 0.05), with a significant increase in base deficit from 0.7 +/- 0.7 to 3.5 +/- 0.7 at 15 min (P less than 0.05) and to 2.9 +/- 1.0 at 30 min (P less than 0.05). Fetal PO2 and PCO2 were unchanged. Significant decreases in blood flow and resistance were seen in the umbilical placental circulation as well as in fetal skeletal muscle and intestine. Blood flow and resistance were unchanged in the renal and adrenal vascular beds. Fetal administration of LTC4 caused no changes in maternal cardiovascular parameters. These findings represent the first in vivo studies of the effects of a lipoxygenase metabolite on fetal-placental blood flow.

Cerebrovascular effects of hypocapnia during adenosine-induced arterial hypotension

1985 ◽  
Vol 63 (6) ◽  
pp. 937-943 ◽  
Author(s):  
David J. Boarini ◽  
Neal F. Kassell ◽  
James A. Sprowell ◽  
Julie J. Olin ◽  
Hans C. Coester
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Arterial Hypotension ◽  
Content Type ◽  
Blood Flows ◽  
Before And After ◽  
Regional Blood Flows ◽  
Fine Print

✓ Profound arterial hypotension is à commonly used adjunct in surgery for aneurysms and arteriovenous malformations. Hyperventilation with hypocapnia is also used in these patients to increase brain slackness. Both measures reduce cerebral blood flow (CBF). Of concern is whether CBF is reduced below ischemic thresholds when both techniques are employed together. To determine this, 12 mongrel dogs were anesthetized with morphine, nitrous oxide, and oxygen, and then paralyzed with pancuronium and hyperventilated. Arterial pCO2 was controlled by adding CO2 to the inspired gas mixture. Cerebral blood flow was measured at arterial pCO2 levels of 40 and 20 mm Hg both before and after mean arterial pressure was lowered to 40 mm Hg with adenosine enhanced by dipyridamole. In animals where PaCO2 was reduced to 20 mm Hg and mean arterial pressure was reduced to 40 mm Hg, cardiac index decreased 42% from control and total brain blood flow decreased 45% from control while the cerebral metabolic rate of oxygen was unchanged. Hypocapnia with hypotension resulted in small but statistically significant reductions in all regional blood flows, most notably in the brain stem. The reported effects of hypocapnia on CBF during arterial hypotension vary depending on the hypotensive agents used. Profound hypotension induced with adenosine does not eliminate CO2 reactivity, nor does it lower blood flow to ischemic levels in this model, even in the presence of severe hypocapnia.

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