Intra-cardiac pressure drop and flow distribution of bicuspid aortic valve disease in preserved ejection fraction.

Background: Bicuspid aortic valve (BAV) is more than a congenital defect since it is accompanied by several secondary complications that intensify induced impairments. Hence, BAV patients need lifelong evaluations to prevent severe clinical sequelae. We applied 4D-flow magnetic resonance imaging (MRI) for in detail visualization and quantification of in vivo blood flow to verify the reliability of the left ventricular (LV) flow components and pressure drops in the silent BAV subjects with mild regurgitation and preserved ejection fraction (pEF). Materials and methods: A total of 51 BAV patients with mild regurgitation and 24 healthy controls were recruited to undergo routine cardiac MRI followed by 4D-flow MRI using 3T MRI scanners. A dedicated 4D-flow module was utilized to pre-process and then analyze the LV flow components (direct flow, retained inflow, delayed ejection, and residual volume) and left-sided [left atrium (LA) and LV] local pressure drop. To elucidate significant diastolic dysfunction in our population, transmitral early and late diastolic 4D flow peak velocity (E-wave and A-wave, respectively), as well as E/A ratio variable, were acquired. Results: The significant means differences of each LV flow component (global measurement) were not observed between the two groups (p > 0.05). In terms of pressure analysis (local measurement), maximum and mean as well as pressure at E-wave and A-wave timepoints at the mitral valve (MV) plane were significantly different between BAV and control groups (p: 0.005, p: 0.02, and p: 0.04 and p: <0.001; respectively). Furthermore, maximum pressure and pressure difference at the A-wave timepoint at left ventricle mid and left ventricle apex planes were significant. Although we could not find any correlation between LV diastolic function and flow components, Low but statistically significant correlations were observed with local pressure at LA mid, MV and LV apex planes at E-wave timepoint (R: -0.324, p: 0.005, R: -0.327, p: 0.004, and R: -0.306, p: 0.008, respectively). Conclusion: In BAV patients with pEF, flow components analysis is not sensitive to differentiate BAV patients with mild regurgitation and healthy control because flow components and EF are global parameters. Inversely, pressure (local measurement) can be a more reliable biomarker to reveal the early stage of diastolic dysfunction.

Rapid Response to Cytokine Storm Inhibition Using Anakinra in a Patient With COVID-19 Myocarditis.

A 62-year-old woman with coronavirus disease 2019 developed acute respiratory failure and cardiogenic shock in the setting of a systemic hyperinflammatory state and apparent ST-elevation myocardial infarction. Cardiac magnetic resonance imaging showed fulminant acute myocarditis with severe left ventricular dysfunction. Treatment with the recombinant interleukin-1 receptor antagonist anakinra and dexamethasone resulted in rapid clinical improvement, reduction in serum inflammatory markers, and a marked recovery in cardiac magnetic resonance--based markers of inflammation and contractile dysfunction. The patient was subsequently discharged from the hospital. Emerging evidence supports use of anti-inflammatory therapies, including anakinra and dexamethasone, in severe cases of coronavirus disease 2019.

Une femme de 62 ans atteinte de la COVID-19 a développé une insuffisance respiratoire aiguë et un choc cardiogène dans le contexte d'un état hyperinflammatoire général et d'un infarctus du myocarde avec élévation du segment ST apparent. L'imagerie par résonance magnétique cardiaque a révélé une myocardite aiguë fulminante accompagnée d'une dysfonction ventriculaire gauche sévère. Le traitement par l'anakinra, un antagoniste des récepteurs de l'interleukine 1 recombinant, et la dexaméthasone, a entraîné une amélioration clinique rapide, une diminution des marqueurs inflammatoires sériques et un rétablissement marqué selon les marqueurs de l'inflammation et de la dysfonction contractile à la résonance magnétique cardiaque. La patiente a par la suite reçu son congé de l'hôpital. De nouvelles données probantes militent en faveur de l'emploi de traitements anti-inflammatoires, comme l'anakinra et la dexaméthasone, dans les cas sévères de COVID-19.

Hemodynamic Assessment in Bicuspid Aortic Valve Disease and Aortic Dilation: New Insights From Voxel-By-Voxel Analysis of Reverse Flow, Stasis, and Energetics.

Objectives: Clinical management decisions surrounding ascending aorta (AAo) dilation in bicuspid aortic valve (BAV) disease benefit from personalized predictive tools. 4D-flow MRI may provide patient-specific markers reflective of BAV-associated aortopathy. This study aims to explore novel 4D-flow MRI parametric voxel-by-voxel forward flow, reverse flow, kinetic energy and stasis in BAV disease. We hypothesize that novel parametric voxel-by-voxel markers will be associated with aortic dilation and referral for surgery and can enhance our understanding of BAV hemodynamics beyond standard metrics. Methods: A total of 96 subjects (73 BAV patients, 23 healthy controls) underwent MRI scan. Healthy controls had no known cardiovascular disease. Patients were clinically referred for AAo dilation assessment. Indexed diameters were obtained by dividing the aortic diameter by the patient's body surface area. Patients were followed for the occurrence of aortic surgery. 4D-flow analysis was performed by a single observer in five regions: left ventricular outflow tract (LVOT), AAo, arch, proximal descending aorta (PDAo), and distal descending aorta (DDAo). In each region peak velocity, kinetic energy (KE), forward flow (FF), reverse flow (RF), and stasis were measured on a voxel-by-voxel basis. T-tests (or non-parametric equivalent) compared flow parameters between cohorts. Univariate and multivariate analyses explored associations between diameter and parametric voxel-by-voxel parameters. Results: Compared to controls, BAV patients showed reduced stasis (p < 0.01) and increased RF and FF (p < 0.01) throughout the aorta, and KE remained similar. In the AAo, indexed diameter correlated with age (R = 0.326, p = 0.01), FF (R = -0.648, p < 0.001), RF (R = -0.441, p < 0.001), and stasis (R = -0.288, p < 0.05). In multivariate analysis, FF showed a significant inverse association with AAo indexed diameter, independent of age. During a median 179 ± 180 days of follow-up, 23 patients (32%) required aortic surgery. Compared to patients not requiring surgery, they showed increased KE and peak velocity in the proximal aorta (p < 0.01), accompanied by increased RF and reduced stasis throughout the entire aorta (p < 0.01). Conclusion: Novel voxel-by-voxel reverse flow and stasis were altered in BAV patients and are associated with aortic dilation and surgical treatment.

Left atrial vortex size and velocity distributions by 4D flow MRI in patients with paroxysmal atrial fibrillation: Associations with age and CHA2 DS2 -VASc risk score.

BACKGROUND: Characterization of left atrial (LA) hemodynamics in paroxysmal atrial fibrillation (PAF) may provide valuable insights for thromboembolic risk. PURPOSE: To evaluate LA vortex formation and velocity distributions by 4D flow MRI and identify associations with age, LA/LV (left ventricle) function, and established risk scores. STUDY TYPE: Prospective clinical. POPULATION: Patients with PAF (n = 45, 46 ± 14 years) and healthy controls (n = 15, 54 ± 9 years) were enrolled. MRI SEQUENCES: 3T standardized cardiac MRI protocol inclusive of 4D flow MRI. ASSESSMENT: Flow analysis planes were prescribed at each pulmonary vein. Velocity distribution analysis and vortex size quantification by the Lambda2 (λ2 ) method were performed in the LA. STATISTICS: Pearson or Spearman's correlation coefficients, r, were calculated to identify relationships between 4D flow-derived LA parameters and age, LA/LV function, and CHA2 DS2 -VASc stroke risk score. Univariate and multivariate determinants of stroke risk were assessed using linear regressions. To compare parameters within multiple groups, one-way analysis of variance or Kruskal-Wallis was used. RESULTS: LA vortice sizes were observed in all subjects using λ2 showing inverse correlations with peak pulmonary vein inflow velocities (P < 0.05), and positive correlations with LA volume (P < 0.05). Vortex size was elevated in PAF at all phases of the cardiac cycle, being most prominent at end early diastole (3.98 ± 1.84 cm3 vs. 6.93 ± 3.11 cm3 , P = 0.001). Velocity distribution analysis showed a greater incidence of flow stasis among patients with PAF (P < 0.05). In univariate regression, vortex size was associated with the CHA2 DS2 -VASc risk score at peak systole (0.457 ± 0.038, P ≤ 0.001). However, in multivariate regression age was the dominant determinant of stroke risk (0.348 ± 0.012, P = 0.006). DATA CONCLUSION: This study demonstrated that LA vortex size is increased among low-risk patients with PAF and is associated with the CHA2 DS2 -VASc risk score. Age remained the dominant determinant of stroke risk. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:871-884.

Pressure drop mapping using 4D flow MRI in patients with bicuspid aortic valve disease: A novel marker of valvular obstruction.

BACKGROUND: The influence of complex bicuspid aortic valve (BAV) flow patterns on net intraluminal aortic pressure, both among patients with and without significant aortic stenosis, is unknown. Pressure drop (PD), as estimated by 4D Flow MRI, can quantify pre- vs post-valvular pressure at multiple levels simultaneously. METHODS: In this prospective clinical study, 32 patients with BAV with varying degrees of aortic stenosis and regurgitation and 11 healthy subjects were enrolled. 4D flow MRI was processed and analyzed at 9 pre-defined thoracic aortic levels. PD was calculated at each plane relative to a reference located within the left ventricular outflow tract. Conventional 2D phase-contrast imaging was used as reference of hemodynamic obstruction. PD was compared between healthy subjects versus BAV patients using Kruskal-Wallis H test and Mann-Whitney U. Correlation studies were conducted using Spearman's rank-order correlation. RESULTS: Both BAV patients and healthy subjects showed progressive elevation in PD from the aortic root to the distal descending thoracic aorta. However, BAV patients showed higher PD than healthy subjects (p ≤ 0.01) at all analysis planes. Patients with moderate-severe aortic stenosis (n = 5) by 2D phase-contrast (peak PG > 40 mm Hg) showed higher PD than those without in the descending aortic segments (p ≤ 0.005). A correlation (r = 0.88, p < 0.05) was observed between PD at the distal descending thoracic aorta and peak trans-valvular velocity measured by 2D phase-contrast MRI. CONCLUSION: We demonstrated that PD with 4D flow MRI is clinically feasible in BAV patients and provides an additional physiologic description of valve-related hemodynamic obstruction.

Application of Lung-Screening Reporting and Data System Versus Pan-Canadian Early Detection of Lung Cancer Nodule Risk Calculation in the Alberta Lung Cancer Screening Study.

BACKGROUND: False-positive scans and resultant needless early recalls can increase harms and reduce cost-effectiveness of low-dose CT (LDCT) lung cancer screening. How LDCT scans are interpreted and classified may impact these metrics. METHODS: The Pan-Canadian Early Detection of Lung Cancer risk calculator was used to determine nodule risk of malignancy on baseline screening LDCTs in the Alberta Lung Cancer Screening Study, which were then classified according to Nodule Risk Classification (NRC) categories and ACR Lung Screening Reporting and Data System (Lung-RADS). Test performance characteristics and early recall rates were compared for each approach. RESULTS: In all, 775 baseline screens were analyzed. After a mean of 763 days (±203) of follow-up, lung cancer was detected in 22 participants (2.8%). No statistically significant differences in sensitivity, specificity, or area under the receiver operator characteristic curve occurred between the NRC and Lung-RADS nodule management approaches. Early recall rates were 9.2% and 9.3% for NRC and Lung-RADS, with the NRC unnecessarily recalling some ground glass nodules, and the Lung-RADS recalling many smaller solid nodules with low risk of malignancy. CONCLUSION: Performances of both the NRC and Lung-RADS in this cohort were very good with a trend to higher sensitivity for the NRC. Early recall rates were less than 10% with each approach, significantly lower than rates using the National Lung Screening Trial cutoffs. Further reductions in early recall rates without compromising sensitivity could be achieved by increasing the NRC threshold to 20% for ground glass nodules or by applying the nodule risk calculator with a 5% threshold to 6- to 10-mm solid nodules under Lung-RADS.

Identifying lesion growth with MR imaging in acute ischemic stroke.

PURPOSE: To determine whether different MR diffusion- and perfusion-weighted imaging (DWI and PWI) parameters are important in distinguishing lesion growth from the acute lesion and from oligemia. MATERIALS AND METHODS: MR DWI and PWI were acquired from thirteen patients. We defined three regions: (i) LESION - intersection of acute and final lesions, (ii) GROWTH - portion of final lesion not part of acute lesion, and (iii) OLIGEMIA - region of perfusion abnormality not part of either the acute or final lesions. We used logistic regression modeling to distinguish GROWTH from LESION and from OLIGEMIA on a voxel-wise basis using DWI- and PWI-based parameters. Final models were selected based on the Wald statistic and validated by cross-validation using the mean (+/- standard deviation) area under the curve (AUC) from receiver operating characteristic analysis. RESULTS: The final model for differentiating GROWTH from LESION included DWI, the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and tissue type (AUC = 0.939 +/- 0.028). The final model for differentiating GROWTH from OLIGEMIA included DWI, ADC, CBF, and time-to-peak (AUC = 0.793 +/- 0.106). CONCLUSION: Different MR parameters are important in differentiating lesion growth from acute lesion and from oligemia in acute ischemic stroke.

MR perfusion and diffusion in acute ischemic stroke: human gray and white matter have different thresholds for infarction.

It is thought that gray and white matter (GM and WM) have different perfusion and diffusion thresholds for cerebral infarction in humans. We sought to determine these thresholds with voxel-by-voxel, tissue-specific analysis of co-registered acute and follow-up magnetic resonance (MR) perfusion- and diffusion-weighted imaging. Quantitative cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and apparent diffusion coefficient (ADC) maps were analyzed from nine acute stroke patients (imaging acquired within 6 h of onset). The average values of each measure were calculated for GM and WM in normally perfused tissue, the region of recovered tissue and in the final infarct. Perfusion and diffusion thresholds for infarction were determined on a patient-by-patient basis in GM and WM separately by selecting thresholds with equal sensitivities and specificities. Gray matter has higher thresholds for infarction than WM (P<0.009) for CBF (20.0 mL/100 g min in GM and 12.3 mL/100 g min in WM), CBV (2.4 mL/100 g in GM and 1.7 mL/100 g in WM), and ADC (786 x 10(-6) mm(2)/s in GM and 708 x 10(-6) mm(2)/s in WM). The MTT threshold for infarction in GM is lower (P=0.014) than for WM (6.8 secs in GM and 7.1 secs in WM). A single common threshold applied to both tissues overestimates tissue at risk in WM and underestimates tissue at risk in GM. This study suggests that tissue-specific analysis of perfusion and diffusion imaging is required to accurately predict tissue at risk of infarction in acute ischemic stroke.

A novel method to derive separate gray and white matter cerebral blood flow measures from MR imaging of acute ischemic stroke patients.

Perfusion-weighted imaging (PWI) measures can predict tissue outcome in acute ischemic stroke. Accuracy might be improved if differential tissue susceptibility to ischemia is considered. We present a novel voxel-by-voxel analysis to characterize cerebral blood flow (CBF) separately in gray (GM) and white matter (WM). Ten patients were scanned with inversion-recovery spin-echo EPI (IRSEPI), diffusion-weighted imaging (DWI), PWI<6 h from onset and fluid attenuated inversion-recovery (FLAIR) at 30 days. Image processing included coregistration to PWI, automatic segmentation of IRSEPI into GM, WM and CSF and semiautomatic segmentation of DWI/FLAIR to derive the acute and 30-day lesions. Five tissue compartments were defined: (1) 'Core' (abnormal acutely and at 30 days), (2) 'Growth' (or 'infarcted penumbra', abnormal only at 30 days), (3) 'Reversed' (abnormal acutely but normal at 30 days), (4) 'MTT-Delayed ' (tissue with delayed mean transit time but not part of the acute or 30-day lesion), and (5) 'Normal' brain. Cerebral blood flow in GM and WM of each compartment was obtained from quantitative maps. Gray matter and WM mean CBF in the growth region differed by 5.5 mL/100 g min (P=0.015). Mean CBF also differed significantly within normal and MTT-Delayed compartments. The difference in the reversed region approached statistical significance. In core, GM and WM CBF did not differ. The results suggest separate ischemic thresholds for GM and WM in stroke penumbra.