Phase-contrast Cine Research Articles

硬膜欠損の同定にphase-contrast cine MRIが有用であった脳表ヘモジデリン沈着症の1例

硬膜欠損の同定にphase-contrast cine MRIが有用であった脳表ヘモジデリン沈着症の1例

Feasibility of ventricular volumetry by cardiovascular MRI to assess cardiac function in the fetal sheep.

The application of fetal cardiovascular magnetic resonance imaging (CMR) to assess fetal cardiovascular physiology and cardiac function through the quantification of ventricular volumes has previously been investigated, but the approach has not yet been fully validated. Ventricular output measurements calculated from heart rate and stroke volumes (SV) of the right and left ventricles measured by ventricular volumetry (VV) exhibited a high level of agreement with phase-contrast (PC) blood flow measurements in the main pulmonary artery and ascending aorta, respectively. Ejection fraction of the right ventricle, which is lower than that of the left ventricle in postnatal subjects, was similar to the left ventricular ejection fraction in the fetus; probably due to the different loading conditions present in the fetal circulation. This study provides evidence to support the reliability of VV in the sheep fetus, providing evidence for its use in animal models of human diseases affecting the fetal circulation. The application of ventricular volumetry (VV) by cardiovascular magnetic resonance imaging (CMR) in the fetus remains challenging due to the small size of the fetal heart and high heart rate. The reliability of this technique in utero has not yet been established. The aim of this study was to assess the feasibility and reliability of VV in a fetal sheep model of human pregnancy. Right and left ventricular outputs by stroke volume (SV) measured using VV were compared with 2D phase-contrast (PC) CMR measurements of blood flow in the main pulmonary artery (MPA) and ascending aorta (AAo). At 124-140days (d) gestation, singleton bearing Merino ewes underwent CMR under general anaesthesia using fetal femoral artery catheters, implanted at 109-117d, to trigger cine steady state free precession acquisitions of ventricular short-axis stacks. The short-axis cine stacks were segmented at end-systole and end-diastole, yielding right and left ventricular SV, ejection fraction, and cardiac outputs (SV×heart rate). PC cine acquisitions of MPA and AAo were analysed to measure blood flow, which served as comparators for the right and left cardiac outputs by VV. There was good correlation and agreement between VV and PC measures of ventricular outputs with no significant bias (r2 =0.926; P<0.0001; Bias=-4.7±10.5mlmin-1 kg-1 ; 95% limits of agreement: -15.9 to 25.2mlmin-1 kg-1 ). This study validates fetal VV by CMR in a large animal model of human pregnancy and provides preliminary reference values of fetal sheep right and left ventricles in late gestation.

Assessment of cardiac function, blood flow and myocardial tissue relaxation parameters at 0.35 T.

A low field strength (B0) system could increase cardiac MRI availability for patients otherwise contraindicated at higher field. Lower equipment costs could also broaden cardiac MR accessibility. The current study investigated the feasibility of cardiac function with steady-state free precession and flow assessment with phase contrast (PC) cine images at 0.35 T, and evaluated differences in myocardial relaxation times using quantitative T1, T2 and T2* maps by comparison with 1.5 and 3 T results in a small cohort of six healthy volunteers. Signal-to-noise ratio (SNR) differences across systems were characterized with proton density-weighted spin echo phantom data. SNR at 0.35 T was lower by factors of 5.5 and 15.0 compared with the 1.5 and 3 T systems used in this study. All cine images at 0.35 T scored 3 or greater on a five-point image quality scale. Normalized blood-myocardium contrast in cine images, left ventricular volumes (end diastolic volume, end systolic volume) and function (ejection fraction and stroke volume) measures at 0.35 T matched 1.5 and 3 T results. Phase-to-noise ratio in 0.35 T PC images (11.7 ± 1.9) was lower than 1.5 T (18.7 ± 5.2) and 3 T (44.9 ± 16.5). Peak velocity and stroke volume determined from PC images were similar across systems. Myocardial T1 increased (564 ± 13 ms at 0.35 T, 955 ± 19 ms at 1.5 T and 1200 ± 35 ms at 3 T) while T2 (59 ± 4 ms at 0.35 T, 49 ± 3 ms at 1.5 T and 40 ± 2 ms at 3 T) and T2* (42 ± 8 ms at 0.35 T, 33 ± 6 ms at 1.5 T and 24 ± 3 ms at 3 T) decreased with increasing B0. Despite SNR deficits, cardiovascular function, flow assessment and myocardial relaxation parameter mapping is feasible at 0.35 T using standard cardiovascular imaging sequences.

Fast Phase-Contrast Cine MRI for Assessing Intracranial Hemodynamics and Cerebrospinal Fluid Dynamics.

We propose fast phase-contrast cine magnetic resonance imaging (PC-cine MRI) to allow breath-hold acquisition, and we compared intracranial hemo- and hydrodynamic parameters obtained during breath holding between full inspiration and end expiration. On a 3.0 T MRI, using electrocardiogram (ECG)-synchronized fast PC-cine MRI with parallel imaging, rectangular field of view, and segmented k-space, we obtained velocity-mapped phase images at the mid-C2 level with different velocity encoding for transcranial blood flow and cerebrospinal-fluid (CSF) flow. Next, we calculated the peak-to-peak amplitudes of cerebral blood flow (ΔCBF), cerebral venous outflow, intracranial volume change, CSF pressure gradient (ΔPG), and intracranial compliance index. These parameters were compared between the proposed and conventional methods. Moreover, we compared these parameters between different utilized breath-hold maneuvers (inspiration, expiration, and free breathing). All parameters derived from the fast PC method agreed with those from the conventional method. The ΔPG was significantly higher during full inspiration breath holding than at the end of expiration and during free breathing. The proposed fast PC-cine MRI reduced scan time (within 30 s) with good agreement with conventional methods. The use of this method also makes it possible to assess the effects of respiration on intracranial hemo- and hydrodynamics.

Evaluation of Cerebral Blood Flow Dynamics in Transient Ischemic Attacks Patients with Fast Cine Phase Contrast Magnetic Resonance Angiography.

Fast cine phase contrast magnetic resonance angiography (PC-MRA) has the potential to provide a quantitative measurement method for the diagnosis and treatment of cerebrovascular disease. To evaluation the changes of cerebral blood flow and the characteristics of artery lesion distribution in the patients of transient ischemic attacks (TIA). In all, 98 normal subjects and 106 TIA patients who underwent MRI examination within 72 h after the last symptom onset including the DWI sequence to exclude acute cerebral infarction were enrolled. The blood flow of the cranial total, the area of the internal carotid artery and vertebral artery, the average velocity, and the average blood flow were obtained and compared in normal subjects and TIA group. Analysis of Variance (ANOVA), t-test, and Kruskal-Wallis test were used for statistical assessments. The total cerebral blood flow of the TIA group and normal control group was no significant statistical difference (P > 0.05). The total blood flow decreased with increasing age, and the TIA group was much lower than the control group. The blood flow of the right internal carotid artery in the TIA group had a significant difference compared with controls (P < 0.05). However, the same situation did not happen in both of the left internal carotid artery and vertebral artery. Phase contrast magnetic resonance imaging has the potential to evaluate the change of cerebral blood flow in TIA patients. The decrease in the total blood flow and the symptom onset of TIA is consistent. Phase contrast magnetic resonance imaging could provide guidance to the diagnosis of TIA.

Longitudinal analysis of cerebral aqueduct flow measures: multiple sclerosis flow changes driven by brain atrophy

BackgroundSeveral small cross-sectional studies have investigated cerebrospinal fluid (CSF) flow dynamics in multiple sclerosis (MS) patients and have reported mixed results. Currently, there are no longitudinal studies that investigate CSF dynamics in MS patients.ObjectiveTo determine longitudinal changes in CSF dynamics measured at the level of aqueduct of Sylvius (AoS) in MS patients and matched healthy controls (HCs).Materials and methodsForty (40) MS patients and 20 HCs underwent 3T MRI cine phase contrast imaging with velocity-encoded pulse-gated sequence at baseline and 5-year follow-up. For atrophy determination, MS patients underwent additional high-resolution 3D T1-weighted imaging. Measures of AoS cross-sectional area (CSA), average systolic and diastolic velocity peaks, maximal systolic and diastolic velocity peaks and average CSF flow rates were determined. Brain atrophy and ventricular CSF (vCSF) expansion rates were determined. Cross-sectional and longitudinal changes were derived by analysis of covariance (ANCOVA) and paired repeated tests. Confirmatory general linear models were also performed. False discovery rate (FDR)-corrected p-values lower than 0.05 were considered significant.ResultsThe MS population demonstrated significant increase in maximal diastolic peak (from 7.23 to 7.86 cm/s, non-adjusted p = 0.037), diastolic peak flow rate (7.76 ml/min to 9.33 ml/min, non-adjusted p = 0.023) and AoS CSA (from 3.12 to 3.69 mm2, adjusted p = 0.001). The only differentiator between MS patients and HCs was the greater AoS CSA (3.58 mm2 vs. 2.57 mm2, age- and sex-adjusted ANCOVA, p = 0.045). The AoS CSA change was associated with vCSF expansion rate (age- and sex-adjusted Spearman’s correlation r = 0.496, p = 0.019) and not with baseline nor change in maximal velocity. The expansion rate of the vCSF space explained an additional 23.8% of variance in change of AoS CSA variance when compared to age and sex alone (R2 = 0.273, t = 2.557, standardized β = 0.51, and p = 0.019).ConclusionMS patients present with significant longitudinal AoS enlargement, potentially due to regional atrophy changes and ex-vacuo expansion of the aqueduct.

Incremental prognostic value of coronary flow reserve determined by phase-contrast cine cardiovascular magnetic resonance of the coronary sinus in patients with diabetes mellitus

BackgroundAlthough non-invasive assessment of coronary flow reserve (CFR) by cardiovascular magnetic resonance (CMR) provides prognostic information for patients with diabetes mellitus (DM), the incremental prognostic value of CMR-derived CFR remains unclear.PurposeTo evaluate the incremental prognostic value of CMR-derived CFR for patients with DM who underwent stress CMR imaging.Materials and methodsA total of 309 patients with type 2 DM [69 ± 9 years; 244 (78%) male] assessed between 2009 and 2019 were retrospectively reviewed. Coronary sinus blood flow (CSBF) was measured using phase contrast (PC) cine CMR. CFR was calculated as the CSBF during adenosine triphosphate infusion divided by that at rest. Major adverse cardiac events (MACE) were defined as death, acute coronary syndrome, hospitalization due to heart failure exacerbation, or sustained ventricular tachycardia. The incremental prognostic value of CFR over clinical and CMR variables was assessed by calculating the C-index and net reclassification improvement (NRI).ResultsDuring a median follow-up of 3.8 years, 42 patients (14%) experienced MACE. The annualized event rate was significantly higher among patients with CFR < 2.0, regardless of the presence of late gadolinium enhancement (LGE) (1.4% vs. 9.8%, p = 0.011 in the LGE (−) group; 1.8% vs. 16.9%, p < 0.001 in the LGE (+) group). In addition, this trend was maintained in the subgroups stratified by presence or absence of ischemia (0.3% vs. 6.7%, p = 0.007 in the ischemia (−) group; 3.9% vs. 17.1%, p = 0.001 in the ischemia (+) group). Adding CFR to the risk model (age + gender + left ventricular ejection fraction + %LGE + %ischemia) resulted in a significant increase of the C-index from 0.838 to 0.870 (p = 0.038) and an NRI of 0.201 (0.004–0.368, p = 0.012).ConclusionPC cine CMR-derived CFR of the coronary sinus may be useful as a prognostic marker for DM patients, incremental to common clinical and CMR parameters. Due to the high prevalence of coronary microvascular dysfunction, the addition of CFR to conventional vasodilator stress CMR imaging may improve risk stratification for patients with DM.

Optimal Plane Selection for Measuring Post-prandial Blood Flow Increase within the Superior Mesenteric Artery: Analysis Using 4D Flow and Computational Fluid Dynamics.

Purpose:2D cine phase contrast (PC)-MRI is a standard velocimetry for the superior mesenteric artery (SMA); however, the optimal localization of the measurement plane has never been fully discussed previously. The purpose of this Institutional Review Board approved prospective and single arm study is to test whether flow velocimetry of the SMA with combined use of 2D cine PC-MRI and meal challenge is dependent on the localizations of the measurement planes and to seek optimal section for velocimetry.Methods:Seven healthy volunteers underwent cardiac phase resolved ECG gated 2D cine PC-MRI pre- and 30 min post-meal challenge at three measurement planes: proximal, curved mid section and distal straight section of the SMA at 3T. 4D Flow using 3D cine PC-MRI with vastly undersampled isotropic projection imaging (PC VIPR) was also performed right after 2D cine PC-MRI to delineate the flow dynamics within the SMA using streamline analysis. Two radiologists measured flow velocities, and rated the appearances of the abnormal flow in the SMA on streamlines derived from the 4D Flow and the computational fluid dynamics (CFD).Results:2D cine PC-MRI measured increased temporally averaged flow velocity (mm/s) after the meal challenge only in the proximal (129.3 vs. 97.8, P = 0.0313) and distal section (166.9 vs. 96.2, P = 0.0313), not in the curved mid section (113.1 vs. 85.5, P = 0.0625). The average velocities were highest and their standard errors (8.5–26.5) were smallest at the distal straight section both before and after the meal challenge as compared with other sections. The streamline analysis depicted more frequent appearances of vertical or helical flow in the curved mid section both on 4D Flow and CFD (κ: 0.27–0.68).Conclusion:SMA velocimetry with 2D cine PC-MRI was dependent on the localization of the measurement planes. Distal straight section, not in the curved mid section is recommended for MR velocimetry.

Altered regional myocardial velocities by tissue phase mapping and feature tracking in pediatric patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is associated with heart failure, atrial fibrillation and sudden death. Reduced myocardial function has been reported in HCM despite normal left ventricular (LV) ejection fraction. Additionally, LV fibrosis is associated with elevated T1 and might be an outcome predictor. To systematically compare tissue phase mapping and feature tracking for assessing regional LV function in children and young adults with HCM and pediatric controls, and to evaluate structure-function relationships among myocardial velocities, LV wall thickness and myocardial T1. Seventeen pediatric patients with HCM and 21 age-matched controls underwent cardiac MRI including standard cine imaging, tissue phase mapping (two-dimensional cine phase contrast with three-directional velocity encoding), and modified Look-Locker inversion recovery to calculate native global LV T1. Maximum LV wall thickness was measured on cine images. LV radial, circumferential and long-axis myocardial velocity time courses, as well as global and segmental systolic and diastolic peak velocities, were quantified from tissue phase mapping and feature tracking. Both tissue phase mapping and feature tracking detected significantly decreased global and segmental diastolic radial and long-axis peak velocities (by 12-51%, P<0.001-0.05) in pediatric patients with HCM vs. controls. Feature tracking peak velocities were lower than directly measured tissue phase mapping velocities (mean bias = 0.3-2.9cm/s). Diastolic global peak velocities correlated moderately with global T1 (r = -0.57 to -0.72, P<0.01) and maximum wall thickness (r = -0.37 to -0.61, P<0.05). Both tissue phase mapping and feature tracking detected myocardial velocity changes in children and young adults with HCM vs. controls. Associations between impaired diastolic LV velocities and elevated T1 indicate structure-function relationships in HCM.

Myocardial velocity, intra-, and interventricular dyssynchrony evaluated by tissue phase mapping in pediatric heart transplant recipients.

Endomyocardial biopsy (EMB) is the standard method for detecting allograft rejection in pediatric heart transplants (Htx). As EMB is invasive and carries a risk of complications, there is a need for a noninvasive alternative for allograft monitoring. To quantify left and right ventricular (LV & RV) peak velocities, velocity twist, and intra-/interventricular dyssynchrony using tissue phase mapping (TPM) in pediatric Htx compared with controls, and to explore the relationship between global cardiac function parameters and the number of rejection episodes to these velocities and intra-/interventricular dyssynchrony. Prospective. Twenty Htx patients (age: 16.0 ± 3.1 years, 11 males) and 18 age- and sex-matched controls (age: 15.5 ± 4.3 years, nine males). 5T; 2D balanced cine steady-state free-precession (bSSFP), TPM (2D cine phase contrast with three-directional velocity encoding). LV and RV circumferential, radial, and long-axis velocity-time curves, global and segmental peak velocities were measured using TPM. Short-axis bSSFP images were used to measure global LV and RV function parameters. A normality test (Lilliefors test) was performed on all data. For comparisons, a t-test was used for normally distributed data or a Wilcoxon rank-sum test otherwise. Correlations were determined by a Pearson correlation. Htx patients had significantly reduced LV (P < 0.05-0.001) and RV (P < 0.05-0.001) systolic and diastolic global and segmental long-axis velocities, reduced RV diastolic peak twist (P < 0.01), and presented with higher interventricular dyssynchrony for long-axis and circumferential motions (P < 0.05-0.001). LV diastolic long-axis dyssynchrony (r = 0.48, P = 0.03) and RV diastolic peak twist (r = -0.64, P = 0.004) significantly correlated with the total number of rejection episodes. TPM detected differences in biventricular myocardial velocities in pediatric Htx patients compared with controls and indicated a relationship between Htx myocardial velocities and rejection history. 2 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:1212-1222.

Quantitative detection of changes in regional wall motion using real time strain-encoded cardiovascular magnetic resonance

A comprehensive cardiovascular magnetic resonance (CMR) exam includes assessment of regional wall motion, which typically involves qualitative interpretation by an experienced reader, although time-consuming quantitative measurements of myocardial wall thickening can be performed. Myocardial strain imaging offers the potential to more accurately quantify the extent and severity of regional wall motion abnormalities and has even been proposed as a mechanism to identify changes in regional contractility before they are visually evident1. Strain imaging may be particularly valuable to assess the impact of coronary artery disease on the myocardium because ischemia is known to first alter the longitudinal deformation of the subendocardial myocardial fibers prior to impacting the regional thickening in the radial direction that is required to create a visually appreciable wall motion abnormality1. In patients with chest pain, alterations in strain following the infusion of an inotrope such as dobutamine can be used to improve the detection of underlying coronary artery disease2. Myocardial strain can be measured using several different CMR-based tagging techniques, such as complementary spatial modulation of magnetization (C-SPAMM) 3 with harmonic phase encoding (HARP) post-processing 4,5, displacement encoding with stimulating echoes (DENSE) 6, cine phase contrast imaging, and strain-encoded CMR (SENC) 7–9. Additionally, it is also possible to use feature tracking algorithms to derive strain measurements from standard cine-CMR images 10,11. Each of these approaches has its advantages and limitations. Recent improvements in SENC-CMR allow for image acquisition to occur during a single heart beat in real time without sacrificing temporal resolution. Unlike the other strain imaging approaches, with SENC imaging being performed during a single heart beat, image quality is not significantly impacted by respiratory motion and arrhythmia. Previous single center studies have suggested that SENC-CMR can be used to improve the detection of coronary artery disease when compared to cine-image wall motion interpretation 12. In this multi-center study, we hypothesized that in the presence of coronary artery disease, changes in regional longitudinal and circumferential strain detected using SENC under intermediate-dose dobutamine stress CMR would precede changes in wall thickening visible on cine-CMR images.

P6. Hydrodynamic change of cerebrospinal fluid flow works for scoliosis formation in a kaolin-induced rabbit model

BACKGROUND CONTEXT Syringomyelia (SM) is often found in scoliosis patients, but the relationship between them is still obscure. The hydrodynamic change of cerebrospinal fluid (CSF) flow has been believed as an important reason of SM. The changes of CSF flow should be included in the researches of scoliosis and associated-SM. PURPOSE Based on a kaolin-induced SM-associated scoliosis rabbit model, the potential relationship between cerebrospinal fluid flow (CSF) flow and scoliosis was explored through magnetic resonance image (MRI) analysis and radiography. STUDY DESIGN/SETTING An experimental study evaluated the relationship between CSF flow and scoliosis formation. PATIENT SAMPLE A total of 50 Japanese white rabbits were included in this study: 40 for experimental kaolin induction, 10 as the control: performing the same surgical process but using the 0.9% saline to instead of kaolin injection. OUTCOME MEASURES The Cobb angle of spinal curve on the coronal plane, the peak velocities of CSF flow, including up-flow (VUmax) and down-flow (VDmax) were measured at different phases. METHODS In 40 rabbits, before and after injecting kaolin into C7 spinal cord, through phase contrast–cine MRI (PC-cine MRI) and radiography, CSF flow and spinal curve formation were recorded at consecutive phases. According to the final formation of scoliosis, the rabbits were divided into 2 groups: scoliosis (group S) and non-scoliosis (group Non-S). The relationship between the changes of CSF flow velocity and scoliosis formation were analyzed. RESULTS In the 37 survived rabbits after kaolin-induction, spinal curve and/or syrinx were observed from week 6. At postoperative 12 weeks, scoliosis was observed in 73.0% animals and involved in group S and the mean final Cobb angle was 27.4°, and the other 10 without scoliosis were involved in group Non-S. In the control, either scoliosis or SM was observed in none. From the comparison between the 2 groups, the differences of the velocities of CSF flow were more obviously from week 4 to 12 after induction, especially at week 6. In the group S, the peak velocity of CSF flow was diseased gradually after induction. Moreover, the changes of VDmax and VUmax from preoperation to postoperative 12 weeks positively correlated to the final Cobb angle (P CONCLUSIONS The SM-associated scoliosis can be induced by kaolin injection into rabbit cervical spinal cord. In this model, the formation of scoliosis is correlated to the hydrodynamic status of CSF flow. The change of CSF flow could be an important potential factor working for the formation of scoliosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

True FISP Cardiac Gated CSF Flow Dynamic Imaging of Chiari Malformation

Abstract INTRODUCTION Brain pulsation and related CSF dynamics is a well-known intraoperative characteristic, but methods for its visualization on magnetic resonance imaging (MRI) have until now been very limited. Best characterized techniques including phase-contrast MRI and cine echo-planar imaging, although of significant value, lack a detailed spatial and temporal resolution needed to investigate CSF and structural dynamics in an adequate manner to address preoperative decision making. Electrocardiographic (ECG)-gated true fast imaging with steady-state precession (FISP) sequences has been widely used to investigate cardiac motion and is capable of demonstrating brain pulsations and movements of intracranial structures surrounded by CSF with high temporal and spatial precision. We feature here the application of true FISP cardiac-gated imaging to the management of 2 patients with Chiari Malformation Type 1 and associated syringohydromyelia. METHODS Two children with Chiari Malformation Type 1 and concurrent syringohydromyelia underwent true FISP cardiac-gated imaging at our institution. RESULTS While conventional imaging studies such as T1 and phase-contrast cine MRI appeared to demonstrate obstruction of CSF flow secondary to tonsillar herniation, true FISP showed patent peritonsillar CSF flow and the presence of a pulsatile arachnoid veil. Subsequently, open surgery confirmed the presence of an arachnoid veil, and postoperative true FISP imaging revealed restoration of CSF flow following arachnoid veil fenestration. CONCLUSION We demonstrated 2 patients who presented with Chiari 1 malformation, where true FISP cardiac imaging was very instructive in visualizing dynamic images of an arachnoid veil and its possible role in the development of syringomyelia without a significant obstruction of outflow by cerebellar tonsils at the foramen of Magendie. We advocate use of this technology will aid in pre and post-surgical decision making, providing a more representative image of posterior fossa pathology in patients with Chiari 1 malformation.

Form follows function: estimation of CSF flow in the third ventricle-aqueduct-fourth ventricle complex modeled as a diffuser/nozzle pump.

In the last 20 years, researchers have debated cerebrospinal fluid (CSF) dynamics theories, commonly based on the classic bulk flow perspective. New hypotheses do not consider a possible hydraulic impact of the ventricular morphology. The present study investigates, by means of a mathematical model, the eventual role played by the geometric shape of the "third ventricle-aqueduct-fourth ventricle" complex in CSF circulation under the assumption that the complex behaves like a diffuser/nozzle (DN) pump. DN pumps are quite recent devices introduced as valveless micropumps in various industrial applications given their property of driving net flow when subjected to rhythmic pulsations. A novel peculiar DN pump configuration was adopted in this study to mimic the ventricular complex, with two reservoirs (the ventricles) and one tube provided with a conical reach (the aqueduct-proximal fourth ventricle). The flow was modeled according to the classic equations of laminar flow, and the external rhythmic pulsations forcing the system were reproduced as a pulsatile pressure gradient between the chambers. Several physiological scenarios were implemented with the integration of data acquired by MRI in 10 patients with no known pathology of CSF dynamics, and a quantitative analysis of the effect of geometric and hydraulic parameters (diverging angle, sizes, frequency of pulsations) on the CSF net flow was performed. The results showed a craniocaudal net flow in all the given values, consistent with the findings of cine MRI studies. Moreover, the net flow estimated for the analyzed cohort of patients ranged from 0.221 to 0.505 ml/min, remarkably close to the values found on phase contrast cine MRI in healthy subjects. Sensitivity analysis underlines the pivotal role of the DN configuration, as well as of the frequency of forcing pressure, which promotes a relevant net flow considering both the heart and respiration rate. This work suggests that the geometry of the third ventricle-aqueduct-fourth ventricle complex, which resembles a diverter, appears to be functional in the generation of a net craniocaudal flow and potentially has an impact on CSF dynamics. These conclusions can be drawn by observing the analogies between the shape of the ventricles and the geometry of DN pumps and by recognizing the basis of the mathematical model of the simplified third ventricle-aqueduct-fourth ventricle complex proposed.

Relationship between intracranial pressure and phase-contrast cine MRI-derived measures of cerebrospinal fluid parameters in communicating hydrocephalus

To explore the correlation between intracranial pressure (ICP) and cerebrospinal fluid (CSF) parameters assessed by phase-contrast cine MRI (PC-MRI). Fifteen normal people and 80 subjects with communicating hydrocephalus who underwent PC-MRI examinations from a single center were included in this cross-sectional study. In addition to recording patient's age, heart rate, blood pressure and body mass index (BMI), ICP and CSF hemodynamic parameters, such as flow velocity and aqueduct diameter, were measured for correlation analysis. The mean ICP and CSF aqueduct diameter in hydrocephalus patients were 151.05 mmH2O and 2.877 mm, respectively, and the maximum (6.938 cm/s) and mean (0.845 cm/s) CSF flow velocities were significantly higher in these patients compared with the controls (P<0.05). After adjusting for age, heart rate, blood pressure, and BMI, there was no significant relationship between peak velocity and ICP (P>0.05). Furthermore, a nonlinear relationship was observed between the ICP and the average velocity of CSF, and the ICP and aqueduct diameter. The ICP increased with the average velocity above 1.628 cm/s (P≤0.01), and the aqueduct diameter increased more than 3.6 mm (P<0.001). This study found significant correlations between ICP and average velocity and aqueduct diameter. These findings can be useful in assisting clinicians in predicting ICP more effectively, thus improving patient management.

ECG Gating Is More Precise Than Peripheral Pulse Gating When Quantifying Spinal CSF Pulsations Using Phase Contrast Cine MRI

To compare accuracy of spinal cerebrospinal fluid (CSF) pulsatile flow measurements at cervical, thoracic, and lumbar levels using Phase Contrast Cine MRI (PCCMRI) with retrospective electrocardiogram (recg) vs. retrospective peripheral pulse gating (rppg) gating. We scanned 10 healthy volunteers, ages 23-46 years, using external recg-gated or rppg-gated 2D PCCCMRI at 3T. Transverse scans of CSF, arteries and veins scans were at C1/C4/T1/T7/L1-L3. Data were analyzed with custom Matlab-based software, measuring CSF, arterial (descending aorta, abdominal aorta, common carotid artery, ICA, and vertebral artery) and venous (internal jugular vein and inferior vena cava) flow, velocity and region of interest area. recgPCCMRI produced less quantitative and temporal statistical variation than pcgPCCMRI when analyzing CSF flow. The instantaneous recgPCCMRI CSF flows consistently decreased craniocaudally, while the results with rppgPCCMRI were less consistent. The recgPCCMRI root mean square error values were 6.04, 6.94, 4.81, 4.49, and 4.16 for C1, C4, T1, T7, and L2, compared with 7.24, 8.97, 7.9, 7.82, and 6.68 for rppgPCCMRI. Results were independent of analysts. Summations of standard errors produced similar results. RppgPCCMRI also showed increase variability of CSF flow correlations with arteries and veins compared to recgPCCMRI. None-the-less, when recgPCCMRI is considered the reference standard, there is good correlations between rppgPCCMRI and recgPCCMRIdata sets, when averaged over cohorts of at least five subjects. Our results indicated that recgPCCMRI is more quantitatively and temporally precise than rppgPCCMRI in CSF quantitative flow analysis. Pulse-gating CSF flow results are reasonable when averaged over cohorts of at least five subjects, but subtle conclusions should be interpreted with caution.

The relationships among spinal CSF flows, spinal cord geometry, and vascular correlations: evidence of intrathecal sources and sinks.

We studied relationships of cerebral spinal fluid (CSF) pulsatile flow at cervical, thoracic, and lumbar levels using phase-contrast cine MRI (PCCMRI) to determine the following: 1) instantaneous and average net flows at cervical, thoracic, and lumbar levels, 2) stochastic correlations of CSF flow with major arterial supplies and major draining veins, and 3) whether adjustments of cord-flow curves-using cord cross-sectional areas, caudal lengths, and caudal volumes-would normalize flow curves from different levels. We scanned 15 healthy volunteers without anesthesia, ages 23-46 yr, using external, retrocardiac-gated, two-dimensional PCCMRI at 3T. Transverse scans of the subarachnoid space, arteries, and veins were acquired and analyzed at cervical, thoracic, and lumbar levels. Instantaneous CSF flow decreased craniocaudally along the full time course of a cardiac cycle. Downward net flow generally increased craniocaudally. During diastole, instantaneous CSF flow decreased proportionally to cross-sectional area, caudal residual length, and caudal residual volume of the cord. The proportionalities were less consistent during systole. CSF, internal carotid artery (ICA), vertebral artery, and lower aorta temporal correlations were highest in systole and decreased craniocaudally. CSF flow temporally correlated better with lower aorta flow than with the ICA at T7 and L2 during systole but not diastole. Inferior vena cava temporal correlation increased craniocaudally. We conclude that whereas instantaneous flow is attenuated cranial caudally, net downward flow, per cardiac cycle, increases caudally, becoming statistically significant at T7 and below the conus medullaris. We can explain the results with the assumption of cord CSF production and peripheral-dominated CSF absorption.

Quantification of Mesenteric Blood Flow by Magnetic Resonance Flow Imaging in Patients with Arterial Dissection.

Mesenteric ischemia is an infrequent, but potentially dangerous, complication of aortic or mesenteric artery dissection. Severe mesenteric ischemia presenting as a malperfusion syndrome, caused by aortic dissection or isolated mesenteric dissection, should be treated immediately by central aortic repair or angioplasty. However, treatment of non-critical, symptomatic mesenteric ischemia without narrowing true lumen of the aorta or localized mesenteric artery dissection was difficult. We treated two distinctly different cases of non-critical, symptomatic mesenteric ischemia superior mesenteric artery ischemia needing intensive care and mesenteric blood flow was determined by quantification with cine-phase contrast magnetic resonance imaging.

Identification of a Dural Defect with Cine Phase Contrast MR Imaging.

Identification of a Dural Defect with Cine Phase Contrast MR Imaging.

The diagnosis of ventriculoperitoneal shunt malfunction by using phase-contrast cine magnetic resonance imaging

The ventriculoperitoneal (VP) shunt is a gold standard procedure to treat hydrocephalus. However, shunt malfunction is the common complications after surgery. In this study, we utilize phase-contrast cine magnetic resonance imaging (PC cine MRI) to improve the diagnosis of VP shunt malfunction. In in vitro and in vivo experiment results demonstrate the cerebrospinal fluid (CSF) flow velocities in the shunt tube are significantly decreased in the shunt malfunction group, which indicated PC cine MRI could evaluate the CSF flow dynamics of VP shunt effectively. This method is noninvasive and simple, also can improve the diagnosis of shunt malfunction.