Three-vessel study of cerebral blood flow using phase-contrast magnetic resonance imaging: Effect of physical characteristics (original) (raw)
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Journal of magnetic resonance imaging : JMRI, 2016
To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by (15) O-H2 O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo against an accepted reference technique. Same-day measurements of CBF by (15) O-H2 O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one-tissue compartment model with measurement of the arterial input function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume-segmented 3D T1 -weighted anatomical MR-scan. Mean CBF was 34.9 ± 3.4 mL/100 g/min measured by (15) O-H2 O PET and 57.0 ± 6.8 mL/100 g/min measured by PCM MRI. The measurements were highly correlated (P = 0.0008, R...
Effect of age and vascular anatomy on blood flow in major cerebral vessels
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2015
Measurement of volume flow rates in major cerebral vessels can be used to evaluate the hemodynamic effects of cerebrovascular disease. However, both age and vascular anatomy can affect flow rates independent of disease. We prospectively evaluated 325 healthy adult volunteers using phase contrast quantitative magnetic resonance angiography to characterize these effects on cerebral vessel flow rates and establish clinically useful normative reference values. Flows were measured in the major intracranial and extracranial vessels. The cohort ranged from 18 to 84 years old, with 157 (48%) females. All individual vessel flows and total cerebral blood flow (TCBF) declined with age, at 2.6 mL/minute per year for TCBF. Basilar artery (BA) flow was significantly decreased in individuals with one or both fetal posterior cerebral arteries (PCAs). Internal carotid artery flows were significantly higher with a fetal PCA and decreased with a hypoplastic anterior cerebral artery. Indexing vessel fl...
Journal of Magnetic Resonance Imaging, 2011
Purpose: To study measurement repeatability and physiological determinants on measurement stability for phase contrast MRI (PC-MRI) measurements of cyclic volume changes (DV) of brain arteries, veins, and cerebrospinal fluid (CSF) compartments. Materials and Methods: Total cerebral blood flow (tCBF), total internal jugular flow (tJBF) and spinal CSF flow at C2-C3 level and CSF in the aqueduct was measured using five repetitions in 20 healthy subjects. After subtracting net flow, waveforms were integrated to calculate DV of arterial, venous, and cerebrospinal fluid compartments. The intraclass correlation coefficient (ICC) was used to measure repeatability. Systematic errors were investigated by a series of phantom measurements. Results: For DV calculated from tCBF, tJBF and both CSF waveforms, the ICC was !0.85. DV from the tCBF waveform decreased linearly between repetitions (P ¼ 0.012). Summed CSF and venous volume being shifted out from the cranium was correlated with DV calculated from the tCBF waveform (r ¼ 0.75; P < 0.001). Systematic errors increased at resolutions <4 pixels per diameter. Conclusion: Repeatability of DV calculated from tCBF, tJBF, and CSF waveforms allows useful interpretations. The subject's time in the MR system and imaging resolution should be considered when interpreting volume changes. Summed CSF and venous volume changes was associated with arterial volume changes.
International Congress Series, 2004
Cerebral blood flow (CBF) obtained by dynamic susceptibility contrast MRI (DSC-MRI) often provides an abnormal contrast between normal and ischemic areas, as compared with those from positron emission tomography (PET) or SPECT. A linear relationship is normally assumed in the transverse relaxation rate change in relation to the regional concentration of the contrast agent. This study was intended to evaluate this assumption. The impact of an alternative, non-linear model based on a realistic capillary structure was also evaluated in the assessment of CBV and CBF by use of DSC-MRI. DSC-MRI and 15 O-PET were carried out on 13 patients with chronic cerebrovascular disease. Regions-of-interest (ROI) were selected both in the ischemic and unaffected hemispheres, and the left-to-right (L/R) ratios of CBF and CBV were compared between PET and DSC-MRI. When assuming the linear relationship, the contrast of CBF by DSC-MRI was lower than that by PET (CBF L/R,MRI = 0.60CBF L/R,PET + 0.40, r = 0.63, p < 0.0216), and the contrast of CBV by DSC-MRI greater than that by PET (CBV L/R,MRI = 1.34CBV L/R,PET À 0.33, r = 0.84, p = 0.0003). Disagreement of CBF was particularly apparent in the area of enhanced CBV. The employment of the non-linear model improved the agreement between DSC-MRI and PET for both CBF and CBV (CBF L/R,MRI = 0.89CBF L/R,PET + 0.08, r = 0.93, p < 0.0001; CBV L/R,MRI = 1.03CBV L/ R,PET À 0.04, r = 0.79, p = 0.0014). These results suggest that the linear model has limited accuracy in the assessment of CBF and CBV in patients with chronic cerebrovascular disease, and that the non-linear correction is essential in order to provide accurate quantitation with DSC-MRI. D 2004 Published by Elsevier B.V.
Comparison of non-invasive MRI measurements of cerebral blood flow in a large multisite cohort
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2016
Arterial spin labeling and phase contrast magnetic resonance imaging provide independent non-invasive methods for measuring cerebral blood flow. We compared global cerebral blood flow measurements obtained using pseudo-continuous arterial spin labeling and phase contrast in 436 middle-aged subjects acquired at two sites in the NHLBI CARDIA multisite study. Cerebral blood flow measured by phase contrast (CBFPC: 55.76 ± 12.05 ml/100 g/min) was systematically higher (p < 0.001) and more variable than cerebral blood flow measured by pseudo-continuous arterial spin labeling (CBFPCASL: 47.70 ± 9.75). The correlation between global cerebral blood flow values obtained from the two modalities was 0.59 (p < 0.001), explaining less than half of the observed variance in cerebral blood flow estimates. Well-established correlations of global cerebral blood flow with age and sex were similarly observed in both CBFPCASL and CBFPC CBFPC also demonstrated statistically significant site differen...
Journal of Cerebral Blood Flow and Metabolism, 2009
The volumetric flow rate (VFR) waveform over the cardiac cycle in the cerebral vasculature is a significant factor in many studies, which involve cerebrovascular function. Perhaps contrary to expectation, the literature in this area is sparse and the characteristics of blood flow waveforms are ill defined. A better understanding of the variation of blood flow rate and pulsatility may aid our knowledge of risk factors involved in diseases and conditions, such as stroke, arteriovenous malformation, or aneurysm rupture. This study sought to characterise the blood flow waveform over the cardiac cycle at levels within the carotid artery and basilar artery (BA) in a normal cohort. The study cohort consisted of 22 subjects (recruitment age: 20 to 40 years) with no history of vascular disease (median age = 26 years, interquartile range = 25 to 32 years). Two-dimensional quantitative phase-contrast magnetic resonance imaging was performed on each subject at nine anatomic locations within the carotid artery and BA. Significant differences in pulsatility were present within the carotid tree. Archetypal VFR waveforms were established for this group at the nine locations. A normal individual's VFR waveform at a location within the carotid tree can be estimated by taking the group's archetypal waveform for that location, and scaling by the individual's average flow rate.
IEEE Transactions on Biomedical Engineering, 2000
This study describes and evaluates a semiautomated method for prescribing an optimal imaging plane that is located as close as possible to the skull base, and is simultaneously nearly perpendicular to the four arteries leading blood to the brain [internal carotid arteries (ICAs) and vertebral arteries (VAs)]. Such a method will streamline and improve reliability of the measurement of total cerebral blood flow and intracranial pressure by velocity encoding phase-contrast magnetic resonance imaging. The method first extracts the vessels' centerline from a 2-D time-of-flight magnetic resonance angiogram of the neck by performing distance transformations. An anatomical marker, the V2 segment of the VAs, is then identified to guide the imaging plane to be as close and below the skull base. An imaging plane that is nearly perpendicular to the ICAs and V2 segment of VAs is then identified by minimizing a misalignment value, estimated by a weighted mean of the angles between the plane's normal and the vessel axes at the vessel-plane intersections. The performance of the semiautomated method was evaluated by comparing manually selected planes to those found semiautomatically in nine magnetic resonance angiogram datasets. The semiautomated method consistently outperformed manual prescription with a significantly smaller misalignment value, 8.6 • versus 20.7 • (P < 0.001), respectively, and significantly improved reproducibility.
A phase-contrast MRI study of physiologic cerebral venous flow
Journal of Cerebral Blood Flow & Metabolism, 2009
Although crucial in regulating intracranial hydrodynamics, the cerebral venous system has been rarely studied because of its structural complexity and individual variations. The purpose of our study was to evaluate the organization of cerebral venous system in healthy adults. Phase-contrast magnetic resonance imaging (PC-MRI) was performed in 18 healthy volunteers, in the supine position. Venous, arterial, and cerebrospinal fluid (CSF) flows were calculated. We found heterogeneous individual venous flows and variable side dominance in paired veins and sinuses. In some participants, the accessory epidural drainage preponderated over the habitually dominant jugular outflow. The PC-MRI enabled measurements of venous flows in superior sagittal (SSS), SRS (straight), and TS (transverse) sinuses with excellent detection rates. Pulsatility index for both intracranial (SSS) and cervical (mainly jugular) levels showed a significant increase in pulsatile blood flow in jugular veins as compared with that in SSS. Mean cervical and cerebral arterial blood flows were 714 ± 124 and 649 ± 178 mL/min, respectively. Cerebrospinal fluid aqueductal and cervical stroke volumes were 41±22 and 460±149 lL, respectively. Our results emphasize the variability of venous drainage for side dominance and jugular/epidural organization. The pulsatility of venous outflow and the role it plays in the regulation of intracranial pressure require further investigation.