scholarly journals Hemodynamic change in patients with hypertrophic obstructive cardiomyopathy before and after alcohol septal ablation using 4D flow magnetic resonance imaging: a retrospective observational study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kenichiro Suwa ◽  
Keitaro Akita ◽  
Keisuke Iguchi ◽  
Takasuke Ushio ◽  
Yuichiro Maekawa
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Observational Study ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Alcohol Septal Ablation ◽  
Before And After ◽  
Flow Mri

Abstract Background The hemodynamics in the left ventricle (LV) and the ascending aorta (AAO) before and after alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM) is elucidated. Our objective was to evaluate the pattern changes in AAO and intra-LV flow assessed by four-dimensional (4D) flow magnetic resonance imaging (MRI) before and after ASA and to clarify the association between 4D flow MRI-derived hemodynamic characteristics and the peak pressure gradient (PPG) in patients with drug-refractory HOCM. Methods In this retrospective observational study, 11 patients with HOCM underwent 4D flow MRI before and a week after ASA. The 4D flow MRI included blood flow visualization and quantification using streamline images. The combined score of vortex and helix in AAO was analyzed. The duration and phase count of the AAO vortex or helix flow and the size of the intra-LV anterior vortex were quantified. The correlation between the changes in hemodynamics and the resting PPG at LV outflow tract was also analyzed. We used the paired t-test for the comparison between before and after ASA and the Pearson’s correlation coefficient for the analysis. Results The combined score for the incidence of vortex and/or helix flow in AAO after ASA was significantly lower than that before ASA (1.45 ± 0.52 vs. 1.09 ± 0.30, p = 0.046). The duration (744 ± 291 ms vs. 467 ± 258 ms, p < 0.001) and phase count (14.8 ± 4.4 phases vs. 10.5 ± 5.8 phases, p < 0.001) of the vortex or helix flow in AAO were significantly decreased after ASA. The LV anterior vortex area after ASA was significantly larger than that before ASA (1628 ± 420 mm2 vs. 2974 ± 539 mm2, p = 0.009). The delta phase count of the AAO vortex or helix before and a week after ASA was significantly correlated with delta PPG before and a week after ASA (R = 0.79, p = 0.004) and with delta PPG before and 6 months after ASA (R = 0.83, p = 0.002). Conclusions Lower vortex or helix flow in AAO and larger diastolic vortex flow in LV were observed after ASA, which suggests the possibility to detect the changes of aberrant hemodynamics in HOCM.

P889Clinical significance of four-dimensional flow magnetic resonance imaging measurement of turbulent kinetic energy for hypertrophic obstructive cardiomyopathy

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
J Matsuda ◽  
H Takano ◽  
T Sekine ◽  
H Sangen ◽  
Y Kubota ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri ◽  
Echocardiographic Findings

Abstract Four-dimensional flow magnetic resonance imaging (4D flow MRI) provides the detailed visualization of complex blood flow patterns and the evaluation of energy loss. Turbulent kinetic energy estimation (TKE) is reported to have good correlation with irreversible pressure loss in patients having aortic stenosis or great vessel disease. However, little is known about the usefulness of 4D flow MRI and the significance of TKE value in hypertrophic cardiomyopathy (HCM). Purpose The aims of this study were to investigate the relationship between TKE value and echocardiographic findings, clinical symptoms and evaluate the usefulness of 4D flow MRI to distinguish hypertrophic obstructive cardiomyopathy (HOCM) from non-obstructive HCM (HNCM). Methods From April 2018 to January 2019, 18 hypertrophic obstructive cardiomyopathy (HOCM) and 14 non-obstructive HCM (HNCM) patients underwent 4D flow MRI. We investigated TKE value calculated by 4D flow MRI, echocardiographic findings; left ventricular pressure gradient (LVPG), mitral regurgitation (MR) and clinical symptom. Results HOCM was defined by the 30 mmHg or greater of LVPG (HOCM: 87.7±47.3 mmHg, HNCM; 5.8±7.8 mmHg, p<0.001). TKE value in HOCM patients was significantly higher than HNCM (14.2±4.7 mJ vs. 9.0±4.6 mJ, p<0.001). There was a significant positive linear relationship between TKE value and LVPG (r=0.488, p=0.046). There was no significant relationship between NYHA functional class and TKE value (p=0.47) or LVPG (p=0.11). ROC curve analysis showed that optimal cut off point of TKE value between HOCM and HNCM (sensitivity=95%, specificity=62%, AUC=0.798) was 9.270 mJ. Multiple linear regression showed that there was significant association between severity of MR and combination of TKE (p=0.015) or LVPG (p–=0.012). A representative case demonstrated the significant reduction of TKE value 1 week and 3 months after alcohol septal reduction compared with that obtained before the procedure (Figure) Conclusion Our findings suggest that 4D Flow MRI can effectively evaluate the energy dissipation associated with LV outflow tract obstruction and TKE value is useful for identifying HOCM. TKE value also can be the novel parameter of the severity of HOCM.

scholarly journals Numerical simulation of time-resolved 3D phase-contrast magnetic resonance imaging

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248816
Author(s):  
Thomas Puiseux ◽  
Anou Sewonu ◽  
Ramiro Moreno ◽  
Simon Mendez ◽  
Franck Nicoud
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
Navier Stokes ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Time Resolved ◽  
Contrast Magnetic Resonance ◽  
Flow Mri

A numerical approach is presented to efficiently simulate time-resolved 3D phase-contrast Magnetic resonance Imaging (or 4D Flow MRI) acquisitions under realistic flow conditions. The Navier-Stokes and Bloch equations are simultaneously solved with an Eulerian-Lagrangian formalism. A semi-analytic solution for the Bloch equations as well as a periodic particle seeding strategy are developed to reduce the computational cost. The velocity reconstruction pipeline is first validated by considering a Poiseuille flow configuration. The 4D Flow MRI simulation procedure is then applied to the flow within an in vitro flow phantom typical of the cardiovascular system. The simulated MR velocity images compare favorably to both the flow computed by solving the Navier-Stokes equations and experimental 4D Flow MRI measurements. A practical application is finally presented in which the MRI simulation framework is used to identify the origins of the MRI measurement errors.

scholarly journals Comparison of Hemodynamic Visualization in Cerebral Arteries: Can Magnetic Resonance Imaging Replace Computational Fluid Dynamics?

2021 ◽  
Vol 11 (4) ◽  
pp. 253
Author(s):  
Minh Tri Ngo ◽  
Ui Yun Lee ◽  
Hojin Ha ◽  
Ning Jin ◽  
Gyung Ho Chung ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cerebral Artery ◽  
Internal Carotid ◽  
Cerebral Arteries ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Tof Mra ◽  
Flow Mri

A multimodality approach was applied using four-dimensional flow magnetic resonance imaging (4D flow MRI), time-of-flight magnetic resonance angiography (TOF-MRA) signal intensity gradient (SIG), and computational fluid dynamics (CFD) to investigate the 3D blood flow characteristics and wall shear stress (WSS) of the cerebral arteries. TOF-MRA and 4D flow MRI were performed on the major cerebral arteries in 16 healthy volunteers (mean age 34.7 ± 7.6 years). The flow rate measured with 4D flow MRI in the internal carotid artery, middle cerebral artery, and anterior cerebral artery were 3.8, 2.5, and 1.2 mL/s, respectively. The 3D blood flow pattern obtained through CFD and 4D flow MRI on the cerebral arteries showed reasonable consensus. CFD delivered much greater resolution than 4D flow MRI. TOF-MRA SIG and CFD WSS of the major cerebral arteries showed reasonable consensus with the locations where the WSS was relatively high. However, the visualizations were very different between TOF-MRA SIG and CFD WSS at the internal carotid artery bifurcations, the anterior cerebral arteries, and the anterior communicating arteries. 4D flow MRI, TOF-MRA SIG, and CFD are complementary methods that can provide additional insight into the hemodynamics of the human cerebral artery.

scholarly journals Multi-Velocity Encoding Four-Dimensional Flow Magnetic Resonance Imaging in the Assessment of Chronic Aortic Dissection

Aorta ◽  
2017 ◽  
Vol 05 (03) ◽  
pp. 80-90
Author(s):  
Andrew Sherrah ◽  
Fraser Callaghan ◽  
Rajesh Puranik ◽  
Richmond Jeremy ◽  
Paul Bannon ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Aortic Dissection ◽  
Surgical Repair ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri

Background: Chronic descending thoracic aortic dissection (CDTAD) following surgical repair of ascending aortic dissection requires long-term imaging surveillance. We investigated four-dimensional (4D)-flow magnetic resonance imaging (MRI) with a novel multi-velocity encoding (multi-VENC) technique as an emerging clinical method enabling the dynamic quantification of blood volume and velocity throughout the cardiac cycle. Methods: Patients with CDTAD (n = 10; mean age, 55.1 years; standard deviation (SD) 10.8) and healthy volunteers (n = 9; mean age, 37.1 years; SD 11.4; p < 0.01) underwent 3T MRI, and standard views and 4D-flow data were obtained. Flow measurements were made in selected regions of interest within the ascending and descending thoracic aorta. Results: The overall flow profile at peak systole was reduced in the false lumen (FL) compared with the true lumen (TL) and normal aortas (p < 0.05 for velocity < 0.4 m/s). Peak systolic flow rate per aortic lumen area (mL/s/cm2) was lower in the FL than in the TL (p < 0.05), and both rates were lower than that of control aortas (p < 0.05). Blood flow reversal was higher in the FL than in the TL throughout the descending aorta in CDTAD patients (p < 0.05). A derived pulsatility index was elevated in the TL compared with that in the FL in CDTAD patients. Generated pathline images demonstrated flow patterns in detail, including sites of communication between the true and FL. Conclusions: 4D-flow MRI revealed FL blood flow and reduced blood flow velocity and flow rate in the TL of CDTAD patients compared with normal aortas of healthy participants. Thus, multi-VENC 4D-flow MRI could serve as an adjunct in the long-term assessment of CDTAD following surgical repair of ascending aortic dissection.

scholarly journals Four-Dimensional Flow Magnetic Resonance Imaging and Applications in Cardiology

2021 ◽  
Author(s):  
Patrick Geeraert ◽  
Hansuk Kim ◽  
Safia Ihsan Ali ◽  
Ashifa Hudani ◽  
Shirin Aliabadi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Great Vessels ◽  
Flow Mri ◽  
Magnetic Resonance Imaging Mri

Blood flow through the heart and great vessels moves in three dimensions (3D) throughout time. However, the assessment of its 3D nature has been limited in the human body. Recent advances in magnetic resonance imaging (MRI) allow for the comprehensive visualization and quantification of in-vivo flow dynamics using four-dimensional (4D) flow MRI. In addition, this technique provides the opportunity to obtain advanced hemodynamic biomarkers such as vorticity, helicity, wall shear stress (WSS), pressure gradients, viscous energy loss (EL), and turbulent kinetic energy (TKE). This chapter will introduce 4D flow MRI which is currently used for blood flow visualization and advanced quantification of cardiac hemodynamic biomarkers. We will discuss its advantages relative to other in-vivo flow imaging techniques and describe its potential clinical applications in cardiology.

Percutaneous transluminal septal myocardial ablation markedly reduces energy loss in hypertrophic obstructive cardiomyopathy: a four-dimensional flow magnetic resonance imaging study

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Z Dai ◽  
N Iguchi ◽  
I Takamisawa ◽  
M Takayama ◽  
M Nanasato ◽  
...  
Keyword(s):  
Energy Loss ◽  
Aortic Root ◽  
Cardiac Cycle ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri ◽  
Percutaneous Transluminal

Abstract Background Functional follow-up modalities of hypertrophic obstructive cardiomyopathy (HOCM) subjected to percutaneous transluminal septal myocardial ablation (PTSMA) are limited mainly to echocardiography and catheterization. Recent advancements in four-dimensional (4D) flow magnetic resonance imaging (MRI) have enabled us to assess patients from the perspective of fluid dynamics by visualising blood flow and calculating quantitative parameters such as wall shear stress and energy loss within cardiac chambers or blood vessels. Several reports have demonstrated that the intra-cardiac energy loss decreased along with improvement of cardiac function achieved by treatment of cardiac diseases. Whether changes in energy loss occur along with PTSMA in HOCM patients and the underlying mechanism remain unknown. Purpose This study sought to investigate the influence of PTSMA in patients with HOCM on energy loss in the left ventricle (LV) and aortic root measured by 4D flow MRI. Methods We retrospectively recruited HOCM patients who underwent PTSMA at a referral centre from May to November 2019. Patients who underwent 4D flow MRI both before and after PTSMA were included. We collected demographic and clinical data from electronic health records. MRI scans implemented two-dimensional phase-contrast imaging of the three-chamber plane with three-directional velocity, using a 1.5 T scanner. Furthermore, 4D blood flow analysis was performed on off-line saved data, using iTFlow version 1.9. We assessed energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root (area surrounded by the LV endocardium, sinotubular junction, and mitral annulus). Results This study finally included 12 patients, whose mean age was 66±12 years, and 5 (42%) of whom were men. The pressure gradient between the LV apex and ascending aorta was 81±32 mmHg before and 20±22 mmHg immediately after PTSMA (P&lt;0.005, paired). Before PTSMA, 6 patients were in New York Heart Association functional class III and the other 6 in class II. However, after PTSMA, 10 patients improved to class I and 2 to class II. PTSMA reduced energy loss in one cardiac cycle within the three-chamber plane of the LV and aortic root, from 79±36 mJ/m to 55±19 mJ/m (P=0.001, paired). Conclusions PTSMA in patients with HOCM reduced energy loss within the LV and aortic root, indicating significant decrease with cardiac workload. Four-dimensional flow MRI of the three-chamber plane to assess energy loss within the LV and aortic root is a time-efficient and reproducible quantitative method to evaluate the effects of PTSMA. Given its non-invasive nature, it also enables to sequentially follow-up HOCM patients who underwent PTSMA. Periprocedural changes of energy loss Funding Acknowledgement Type of funding source: None

scholarly journals Hemodynamic Disturbances in Posterior Circulation Stroke: 4D Flow Magnetic Resonance Imaging Added to Computed Tomography Angiography

2021 ◽  
Vol 15 ◽  
Author(s):  
Jan Malm ◽  
Johan Birnefeld ◽  
Laleh Zarrinkoob ◽  
Anders Wåhlin ◽  
Anders Eklund
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Posterior Circulation ◽  
Resonance Imaging ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Rates ◽  
Flow Mri ◽  
Hemodynamic Disturbance ◽  
Relative Flow

Objective: A clinically feasible, non-invasive method to quantify blood flow, hemodynamics, and collateral flow in the vertebrobasilar arterial tree is missing. The objective of this study was to evaluate the feasibility of quantifying blood flow and blood flow patterns using 4D flow magnetic resonance imaging (MRI) in consecutive patients after an ischemic stroke in the posterior circulation. We also explore if 4D-flow, analyzed in conjunction with computed tomography angiography (CTA), has potential as a diagnostic tool in posterior circulation stroke.Methods: Twenty-five patients (mean age 62 years; eight women) with acute ischemic stroke in the posterior circulation were investigated. At admission, all patients were examined with CTA followed by MRI (4D flow MRI and diffusion-weighted sequences) at median 4 days after the presenting event. Based on the classification of Caplan, patients were divided into proximal/middle (n = 16) and distal territory infarcts (n = 9). Absolute and relative blood flow rates were calculated for internal carotid arteries (ICA), vertebral arteries (VA), basilar artery (BA), posterior cerebral arteries (P1 and P2), and the posterior communicating arteries (Pcom). In a control group consisting of healthy elderly, the 90th and 10th percentiles of flow were calculated in order to define normal, increased, or decreased blood flow in each artery. “Major hemodynamic disturbance” was defined as low BA flow and either low P2 flow or high Pcom flow. Various minor hemodynamic disturbances were also defined. Blood flow rates were compared between groups. In addition, a comprehensive analysis of each patient’s blood flow profile was performed by assessing relative blood flow rates in each artery in conjunction with findings from CTA.Results: There was no difference in total cerebral blood flow between patients and controls [604 ± 117 ml/min vs. 587 ± 169 ml/min (mean ± SD), p = 0.39] or in total inflow to the posterior circulation (i.e., the sum of total VA and Pcom flows, 159 ± 63 ml/min vs. 164 ± 52 ml/min, p = 0.98). In individual arteries, there were no significant differences between patients and controls in absolute or relative flow. However, patients had larger interindividual relative flow variance in BA, P1, and P2 (p = 0.01, &lt;0.01, and 0.02, respectively). Out of the 16 patients that had proximal/middle territory infarcts, nine had CTA findings in VA and/or BA generating five with major hemodynamic disturbance identified with 4D flow MRI. For those without CTA findings, seven had no or minor 4D flow MRI hemodynamic disturbance. Among nine patients with distal territory infarcts, one had major hemodynamic disturbances, while the remaining had minor disturbances.Conclusion: 4D flow MRI contributed to the identification of the patients who had major hemodynamic disturbances from the vascular pathologies revealed on CTA. We thus conclude that 4D flow MRI could add valuable hemodynamic information when used in conjunction with CTA.

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