Quantitative evaluation of extracellular volume in patients with heart failure using dual-layer spectral detector CT: a feasibility study / 中华放射学杂志

Objective:To explore the feasibility in evaluating segmental extracellular volume (ECV) using dual-layer spectral detector CT in patients with heart failure with various percentages of delayed hyper-enhanced volume, using MRI as a reference.Methods:Twenty-seven patients with heart failure in Peking Union Medical College Hospital were prospectively enrolled in this study from July 2019 to January 2021. All the patients underwent both CT late iodine enhancement and MR late gadolinium enhancement imaging within a week. According to percentages of hyper-enhanced volume on cardiac MR image, myocardial segments were classified into 3 groups: 0-4% (group A), 5%-49% (group B) and 50%-100% (group C). ECV images were independently observed by 2 experienced radiologists. The correlation and agreement between CT-ECV and MRI-ECV for the whole myocardial assessment and for the segmental assessment were evaluated using Spearman correlation and Bland-Altman analysis. Inter-observer agreement was assessed using the ICC.Results:Of the 27 patients, 432 segments were analyzed, with 199 segments in group A, 151 segments in group B and 82 segments in group C. In the whole myocardial analysis, the CT-ECV and MRI-ECV were 32.25% (28.04%, 34.28%) and 32.27% (28.35%, 34.77%), respectively. A good correlation was found between CT-ECV and MRI-ECV ( r=0.969, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias (0.4%), with 95% limits of agreement of -6.9% to 7.8%. as for the segmental myocardial assessment, the CT-ECV was 28.23% (26.18%, 29.92%) for group A, 33.29% (30.16%, 35.96%) for group B and 40.22% (34.06%, 46.70%) for group C. There was statistically significant difference in ECV among three groups (all P<0.001). Good correlations between CT-ECV and MRI-ECV were found in group A ( r=0.614, P<0.001), group B ( r=0.852, P<0.001) and group C ( r=0.953, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias 2.0% (95% limits of agreement:-17.6%-21.6%) in group A, a small bias -0.4% (95% limits of agreement: -13.8%-12.9%) in group B and a small bias -1.8% (95% limits of agreement: -17.4%-13.9%) in group C. The ICC values between 2 observers were 0.877 and 0.945 on CT-ECV and MRI-ECV, respectively. Conclusions:The larger percentage of hyper-enhanced volume on cardiac MR image, the stronger correlation are between the CT-ECV and MRI-ECV. CT-ECV may be taken as an alternative tool for quantitative evaluation of myocardial tissue in patients with heart failure.

Cardiac Magnetic Resonance in the Assessment of Chagas Disease and its Complications

Abstract The well-known occurrence of Chagas disease in endemic areas has become a worldwide problem, and cardiac magnetic resonance allows the early detection of cardiac involvement and complications of this disease. Cardiac magnetic resonance is a useful tool in all phases of Chagas disease, and new promising techniques using T1 mapping and extracellular volume measurements are able to detect cardiac involvement even earlier than conventional techniques.

Role of Myocardial Extracellular Volume Fraction Measured with Magnetic Resonance Imaging in the Prediction of Left Ventricular Functional Outcome after Revascularization of Chronic Total Occlusion of Coronary Arteries

OBJECTIVE: The purpose of this study was to prospectively investigate the value of the myocardial extracellular volume fraction (ECV) in predicting myocardial functional outcome after revascularization of coronary chronic total occlusion (CTO). MATERIALS AND METHODS: Thirty patients with CTO underwent cardiovascular magnetic resonance (CMR) before and 6 months after revascularization. Three baseline markers of functional outcome were evaluated in the dysfunctional segments assigned to the CTO vessels: ECV, transmural extent of infarction (TEI), and unenhanced rim thickness (RIM). At the global level, the ECV values of the whole myocardium with and without a hyperenhanced region (global and remote ECV) were respectively measured. RESULTS: In per-segment analysis, ECV was superior to TEI and RIM in predicting functional recovery (area under receiver operating characteristic curve [AUC]: 0.86 vs. 0.75 and 0.73, all p values < 0.010), and it emerged as the only independent predictor of regional functional outcome (odds ratio [OR] = 0.83, 95% confidence interval [CI]: 0.77–0.89; p < 0.001) independent of collateral circulation. In per-patient analysis, global baseline ECV was indicative of ejection fraction (EF) at the follow-up examination (β = −0.61, p < 0.001) and changes in EF (β = −0.57, p = 0.001) in multivariate regression analysis. A patient with global baseline ECV less than 30.0% (AUC, 0.93; sensitivity 94%, specificity 80%) was more likely to demonstrate significant EF improvement (OR: 0.38; 95% CI: 0.17–0.85; p = 0.019). CONCLUSION: Extracellular volume fraction obtained by CMR may provide incremental value for the prediction of functional recovery both at the segmental and global levels in CTO patients, and may facilitate the identification of patients who can benefit from revascularization.

Reply: Prediction of the Left Ventricular Functional Outcome by Myocardial Extracellular Volume Fraction Measured Using Magnetic Resonance Imaging; Methodological Issue

No abstract available.

RE: Prediction of the Left Ventricular Functional Outcome by Myocardial Extracellular Volume Fraction Measured Using Magnetic Resonance Imaging: Methodological Issue

No abstract available.

Extracellular volume fraction for the assessment of myocardial functional outcome after revascularization in the patients with coronary chronic total occlusion / 中华放射学杂志

Objective Myocardial functional outcome after revascularization of coronary chronic total occlusion (CTO) was prospectively predicted using extracellular volume fraction (ECV) based on cardiovascular magnetic resonance (CMR). Methods Thirty patients with CTO underwent CMR before and 6 months after percutaneous coronary intervention (PCI) were enrolled. The CMR scan protocol included cine, pre?contrast and post?contrast T1 mapping and late gadolinium enhancement (LGE). Ejection fraction (EF) and segmental wall thickening (SWT) were calculated using CVI 42 software. SWT less than 45% indicated myocardial segment dysfunction. According to the American Heart Association (AHA) scientific statement, the dysfunctional segments assigned to CTO vessel were selected, and three baseline imaging markers, ECV, transmural extent of infarction (TEI) and unenhanced rim thickness (RIM) were respectively evaluated. The myocardial segments were divided into two subgroups, group with well?developed collaterals and group with poorly?developed collaterals, based on the collateral circulation using Rentrop classification. Baseline and follow?up values of SWT and EF were evaluated using paired Student′s t?test. Using an increase in SWT>10% as standard reference, ROC analysis was conducted to describe the predictive performance of baseline markers. A mixed linear model was used to probe the relationship between collateral circulation and SWT. Stepwise logistic regression analysis was used to determine the independent predictors of regional functional recovery. The differences of EF between poorly?developed and well?developed collaterals were compared by Student t test. Results The baseline mean segmental wall thickening (SWT) of the dysfunctional segments increased from 21.6% (9.7%, 33.3%) to 38.4% (19.0%, 51.2%) after PCI (Z=-6.869, P<0.001), and EF was also significantly higher compared with baseline (54.5%±8.5 % vs. 50.7%± 6.6%, t=-5.706, P<0.001). ECV showed good performance in predicting functional recovery with cutoff value 34.7%, area under ROC curve (AUC) 0.86, sensitivity 91%, and specificity 66%. The AUC of ECV was superior to TEI and RIM (AUC: 0.75 and 0.73, all P value<0.01). The segments with well?developed collaterals were associated with a higher SWT at follow?up [46.6% (36.6%, 64.2%) vs. 33.5% (12.8%, 47.8%),F=5.791, P=0.02]. Logistic regression analysis demonstrated that mean segmental ECV was the only independent predictors of regional functional outcome after PCI (OR=0.83, 95% confidence interval: 0.77—0.89; P<0.001). Conclusions ECV by CMR may provide incremental value for the prediction of regional functional recovery in CTO patients, and baseline collateral circulation correlates with the regional systolic function after revascularization.

Quantitation of diffuse myocardial fibrosis using cardiac CT in heart failure: a pilot study / 中华放射学杂志

Objective To evaluate the feasibility and accuracy of cardiac CT (CCT) in quantitation of extracellular volume (ECV) fraction in patients with heart failure, with 3 T Cardiac MR (CMR) as the reference. Methods Twenty?eight patients with variety reasons of heart failure were enrolled in this study. ECVs was calculated, the correlation between CCT and CMR ECV value and other cardiac function parameters (left ventricular end systolic volume LVESV, left ventricular end diastolic volume LVEDV, cardiac output CO and ejection fraction LVEF, and clinical bio?marker BNP) was determined. Interclass correlation coefficient (ICC) was used to evaluate the agreement of measurement by two radiologists. Results The average of ECV on CCT and CMR was 33% ± 8% and 31% ± 6%, respectively. A good correlation was revealed between myocardial ECV at CCT and that at CMR (r=0.854, P<0.001). Bland?Altman analysis between CCT and CMR showed a small bias (4.6%), with 95% limits of agreement of-18.2% to 27.4%. ICC for ECV at CCT was excellent (ICC=0.910). For both CCT and CMR, ECV was inversely related to LVEF. The radiation dose for CCT?ECV was (1.60±0.04) mSv. Conclusions ECV at CCT and that at CMR showed good correlation, suggesting the potential for myocardial tissue characterization using CCT. However, CCT?ECV would possibly overestimate the extent of ECV.

Application progresses of new cardiovascular MR techniques on valvular heart disease / 中国医学影像技术

Valvular heart disease (VHD) is one kind of the main causes of cardiovascular events in the elderly patients. Cardiac imaging evaluation plays a critical role in the diagnosis and selection of treatment options for VHD. New cardiovascular MR (CMR) techniques have been increasingly used for VHD patients, of which 4D Flow MRI-derived hemodynamic parameters can be used to estimate transvalvular blood flow velocities, pressure gradients, wall shear stress and flow patterns, T1 mapping and extracellular volume fraction enable quantification of changes of early ventricular remodeling secondary to VHD, strain analysis can be used to assess early myocardial dysfunction. The application progresses of new CMR techniques on VHD were reviewed in this article.

Study on diagnostic value of extracellular volume imaging by magnetic resonance imaging for liver fibrosis of hepatitis B / 中华肝脏病杂志

Objective@#To investigate the diagnostic value of extracellular volume (ECV) imaging by magnetic resonance imaging for liver fibrosis of hepatitis B.@*Methods@#A retrospective analysis was recruited in patients with chronic hepatitis B, who underwent liver surgery from April to October 2017 for pathological evaluation of liver tissues, and all patients underwent Gd-EOB-DTPA-enhanced T1 mapping to calculate the liver ECV score. The correlation between ECV and staging of hepatic fibrosis and inflammatory activity were compared to clarify the diagnostic value of staging of fibrosis.@*Results@#66 patients were enrolled in this study. Concerning the staging of liver fibrosis, there were 13, 4, 13, 10, and 26 cases with F0, F1, F2, F3 and F4 stages, respectively. ECV values had high interobserver consistency (correlation coefficient 0.860). The ECV difference between different stages of liver fibrosis was statistically significant (F = 15.02, P < 0.001). There was a significant positive correlation between ECV and fibrosis stage (r = 0.622, P < 0.001), and weak correlation with inflammatory activity (r = 0.332, P = 0.007). Fibrosis staging was an independent factor influencing ECV (P < 0.001). The area under the receiver operator characteristic curve for the diagnosis of liver fibrosis staging F≥1, F≥3 and F4 were 0.760, 0.846 and 0.873, respectively. The diagnostic sensitivity and specificity were 64.15%, 92.31%, 77.78%, 80.00% and 88.46, 72.50%, respectively.@*Conclusion@#MRI-ECV imaging has great value for staging hepatic fibrosis of hepatitis B, and it can provide an effective method for diagnosis, staging, and evaluating the curative effect of fibrosis.

Contour-based Registration for Left Ventricular Myocardial Extracellular Volume Fraction Using T1 Mapping in Healthy Adults / 中山大学学报(医学科学版)

[Objective]We aimed to evaluate the role of contour-based registration in quantification of myocardial extracellular volume fraction(ECV)based on T1 mapping technique.[Methods]T1 mapping images of the basal,mid-cavity and apical short axis slices of 26 healthy volunteers(16 males and 10 females)were obtained before and after administration of contrast agent using Modified Look-Locker Inversion Recovery(MOLLI)on a 3.0T Magnetic Resonance Imaging system.ECV was calculated by routine method and registered method.For each slice,subjects were divided into the deformation subgroup and the control subgroup.Routine ECVs and registered ECVs were compared for each subgroup.[Results]Left ventricular deformation among T1 mapping images occurred in 16 subjects(61.5%). In all three slices, registered ECV maps had better image quality and more highest grade images than routine ECV maps. Routine ECVs[(26.81 ± 2.78)%,(25.38 ± 3.05)%,(28.66 ± 4.10)%]were statistically different from registered ECVs in global [(25.75±2.42)%,P=0.001],mid-cavity[(24.30±2.45)%,P=0.016]and apical slices[(27.22±3.38)%,P=0.010]. In deformation subgroups of all the 3 slices,registered ECVs were lower than routine ECVs with smaller SDs(P=0.038, 0.012,0.016).The apical ECVs were higher with larger SDs than the other two slices and the global ECVs(routine:F=4.799,P=0.004;registered:F=4.822,P=0.003).[Conclusions]Contour-based registration can improve the image qual-ity and precision of ECV quantification in cases with ventricular shape deformation among source images.

Quantitative analysis of left ventricle myocardial fibrosis in patients with atrial fibrillation by cardiac MRI / 中国医学影像技术

Objective To evaluate the diffuse myocardial fibrosis of the left ventricle (LV) in patients with atrial fibrillation (AF) by cardiac MR (CMR) T1 mapping methods.Methods Totally 60 subjects (30 paroxysmal AF patients and 30 persistent AF patients) and 59 normal control underwent MR cardiac cine,late gadolinium enhancement,and LV T1 mapping.For T1 mapping,modified Look-Locker inversion recovery sequence was used.Compared with control,pre-contrast ventricular T1 times were quantified and extracellular volume (ECV) was calculated.Results All subjects completed the CMR exam,no myocardial delay enhanced lesion was found.Pre-contrast ventricular T1 time in healthy controls was lower than that in patients with persistent and paroxysmal AF,and the pre-comrast ventricular T1 time in persistent AF patients was higher than that of paroxysmal AF patients (all P＜0.05).The mean LV myocardial ECV had no statistical difference between healthy controls and paroxysmal AF patients (P＞ 0.05),while lower than persistent AF patients (P ＜ 0.05).The mean LV myocardial ECV in patients with persistent AF was larger than that in patients with paroxysmal AF (P＜0.05).LV functional indexes were positive correlated with pre-contrast ventricular T1 time and ECV in patients with AF (all P＜0.05).Conclusion There is LV myocardial fibrosis in patients with AF,and the degree in patients with persistent AF is more severe than that in patients with paroxysmal AF.

Progress of myocardial T1 mapping technique and clinical applications / 医学研究生学报

T1 mapping is a new magnetic resonance imaging technique .By which the longitudinal relaxation time constant ( T1) of the myocardium can be measured to detect and quantitatively assess various focal or diffuse diseases .T1 mapping has various scan sequences , such as LL sequence , MOLLI sequence and ShMOLLI sequence .T1 mapping can be classified into two groups:pre--contrast and post-contrast T1 mapping.In addition, by measuring post-contrast T1 mapping and pre-contrast T1 mapping, myocardial extra-cellular volume (ECV) can be derived, which has been applied to assess myocardial edema and myocardial fibrosis with great clinical value .This review focuses on the techniques , methods and clinical application of cardiac magnetic resonance T 1 mapping technology .

Comparación de concentración mínima inhibitoria y concentración plasmática de cefalotina mediante un modelo matemático / Comparison of the minimal inhibitory concentration and the plasma cephalotin concentration through a mathematical model

Introducción: el uso de fármacos fuera de rangos terapéuticos es un problema hospitalario, pues pocas veces se tienen en cuenta parámetros antropométricos del paciente, determinantes en las concentraciones del medicamento. Objetivo: aplicar un modelo matemático basado en parámetros del paciente, para determinar las posibles concentraciones plasmáticas de cefalotina y compárarlas con las concentraciones mínimas inhibitorias de los microrganismos aislados. Métodos: se seleccionó un grupo de pacientes del sexo masculino entre 18 y 50 años de edad con tratamiento profiláctico posquirúrgico con cefalotina. Se recopiló la información: dosis de cefalotina, peso, talla, edad, hematócrito. Se calcularon volumen extracelular, plasmático y sanguíneo según el modelo informado por Hedin. Luego se calculó la concentración plasmática de cefalotina usando el modelo propuesto en el presente estudio y se comparó con la concentración mínima inhibitoria de los microorganismos aislados. Resultados: se analizaron 24 pacientes con promedio de edad 32,6 años ± 8, peso de 69 kg ± 7,51, talla de 168,87 cm ± 7,10. El 56,3 por ciento de los microorganismos presentó resistencia a concentraciones ³ 32 µg/mL. El agente más común fue Escherichia coli de 18 cepas aisladas. La comparación del volumen de distribución y la concentración plasmática de cefalotina calculada con el modelo informado por Hedin y el desarrollado en presente trabajo, no presentó diferencia significativa después de aplicar la prueba t de Student, con p< 0,05. Conclusiones: al comparar las concentraciones teóricas de cefalotina para uso profiláctico posquirúrgico intrahospitalario, calculadas con el modelo planteado, se encontró que estas no permitieron superar la concentración mínima inhibitoria de los microorganismos aislados(AU)

Introduction: the use of drugs out of therapeutic ranges is a hospital problem since the anthropometric parameters of patients, which are determinants in the drug concentrations, are rarely taken into consideration. Objectives: to implement a mathematical model based on the patient's parameters in order to determine the possible plasma cephalotine concentrations and to compare them with the minimum inhibitory concentrations for isolated microorganisms. Methods: a group of male patients aged 18 to 50 years under postsurgical prophylactic treatment with cephalotine was selected. Data was collected on cephalotin dosage, weight, size, age and hematocrit. Extracellular, plasma and blood volumes were estimated by the Hedin's informed model. Additionally, the plasma cephalotin concentration was measured by using the model suggested in this study and then compared with the minimum inhibitory concentration for the isolated microorganisms. Results: twenty four patients aged 32.6 years ± 8, weighing 69 kg ± 7.51, with size of 168.87 cm ± 7.10 were analyzed. Resistance to concentrations equal to or higher than 32 µg/mL was observed in 56.3 percent of microorganisms. The most common agent was Escherichia coli in 18 isolated strains. The comparison of the distribution volume and of the plasma cephalotin concentration estimated with the Hedin's informed model and with the model devised in the present paper did not show significant differences according to Student's t test result, with p< 0.05. Conclusions: the comparison of the theoretical concentrations of cephalotine for in-hospital postsurgical prophylactic use estimated by the model yielded that these concentrations did not allow overcoming the minimum inhibitory concentration for the isolated microorganisms(AU)