Mathieu Lederlin

EACVI/EHRA Expert Consensus Document on the role of multi-modality imaging for the evaluation of patients with atrial fibrillation

Atrial fibrillation (AF) is the commonest cardiac rhythm disorder. Evaluation of patients with AF requires an electrocardiogram, but imaging techniques should be considered for defining management and driving treatment. The present document is an expert consensus from the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association. The clinical value of echocardiography, cardiac magnetic resonance (CMR), computed tomography (CT), and nuclear imaging in AF patients are challenged. Left atrial (LA) volume and strain in echocardiography as well as assessment of LA fibrosis in CMR are discussed. The value of CT, especially in planning interventions, is highlighted. Fourteen consensus statements have been reached. These may serve as a guide for both imagers and electrophysiologists for best selecting the imaging technique and for best interpreting its results in AF patients.

In Vivo Micro-CT Assessment of Airway Remodeling in a Flexible OVA-Sensitized Murine Model of Asthma

Airway remodeling is a major pathological feature of asthma. Up to now, its quantification still requires invasive methods. In this study, we aimed at determining whether in vivo micro-computed tomography (micro-CT) is able to demonstrate allergen-induced airway remodeling in a flexible mouse model of asthma. Sixty Balb/c mice were challenged intranasally with ovalbumin or saline at 3 different endpoints (Days 35, 75, and 110). All mice underwent plethysmography at baseline and just prior to respiratory-gated micro-CT. Mice were then sacrificed to assess bronchoalveolar lavage and lung histology. From micro-CT images (voxel size = 46×46×46 µm), the numerical values of total lung attenuation, peribronchial attenuation (PBA), and PBA normalized by total lung attenuation were extracted. Each parameter was compared between OVA and control mice and correlation coefficients were calculated between micro-CT and histological data. As compared to control animals, ovalbumin-sensitized mice exhibited inflammation alone (Day 35), remodeling alone (Day 110) or both inflammation and remodeling (Day 75). Normalized PBA was significantly greater in mice exhibiting bronchial remodeling either alone or in combination with inflammation. Normalized PBA correlated with various remodeling markers such as bronchial smooth muscle size or peribronchial fibrosis. These findings suggest that micro-CT may help monitor remodeling non-invasively in asthmatic mice when testing new drugs targeting airway remodeling in pre-clinical studies.

CT Attenuation of the Bronchial Wall in Patients With Asthma: Comparison With Geometric Parameters and Correlation With Function and Histologic Characteristics

OBJECTIVE The purposes of this study were to compare airway wall attenuation in subjects with asthma and subjects without asthma; to correlate this value with pulmonary function test results, standard bronchial CT parameters, and immunohistologic data; and to identify CT parameters that influence obstructive indexes. SUBJECTS AND METHODS Bronchial airway wall attenuation was averaged over four bronchi in 27 subjects with asthma and 15 control subjects without asthma. The following five standard bronchial parameters also were assessed: lumen area, wall area, wall thickness, wall-to-lumen area ratio, and wall-to-total area ratio (wall area percentage). These parameters were compared between groups and correlated with functional data. Ability to predict patient group with these parameters was determined by comparison of receiver operating characteristic curves and areas under the curve. The influence of the parameters on obstructive indexes was assessed by multivariate analysis. Correlations between wall attenuation value and histologic data were studied in 11 patients with asthma. RESULTS Wall attenuation value was greater in patients with asthma (-322 ± 79 HU) than in control subjects (-463 ± 69 HU). Correlation coefficients of wall attenuation value with functional obstructive parameters were significant and greater than those obtained for any other CT parameter. The area under the curve of wall attenuation value was greater than that of bronchial lumen area and bronchial wall area. In the model of multiple regression that included wall attenuation value and wall-to-total area ratio, wall attenuation value was the only measurement that significantly influenced obstructive indexes (R(2) = 0.39-0.43). Wall attenuation value correlated with mast cell infiltration. CONCLUSION Compared with the usual bronchial CT parameters, airway wall attenuation better differentiates patients with asthma from control subjects and better correlates with obstruction.

Mean bronchial wall attenuation value in chronic obstructive pulmonary disease: comparison with standard bronchial parameters and correlation with function.

OBJECTIVE The objective of our study was to evaluate bronchial wall attenuation values quantified using CT in patients with chronic obstructive pulmonary disease (COPD). SUBJECTS AND METHODS Ninety patients (81 men, nine women; age range, 21-80 years; mean age, 56 years) underwent CT and pulmonary function tests (PFTs). Bronchial wall attenuation value, wall area, and lumen area were averaged over four segmental bronchi in control subjects (n = 30), smokers with COPD (n = 30), and smokers without COPD (n = 30). The bronchial wall thickness, wall area-to-lumen area ratio, and wall area-to-total area ratio were computed. The extent of emphysema was measured as the percentage of area with an attenuation of less than -950 HU. Parameters were compared among groups and were correlated with PFT results. Receiver operating characteristic curves were obtained for each parameter and areas under the curve were compared. Variables responsible for changes in wall attenuation values and those accounting for obstructive indexes were assessed using multiple regressions. RESULTS The wall attenuation value was the only parameter discriminating between each pair of groups (mean ± SD, -293 ± 71 HU in COPD patients, -387 ± 70 HU in smokers, and -457 ± 69 HU in control subjects). The area under the curve of the wall attenuation value was greater than that of any other CT bronchial parameter to separate smokers from COPD patients. Wall attenuation value correlated with PFT results and was influenced by the wall area-to-lumen area ratio. The wall attenuation value, extent of emphysema, and standard bronchial parameters independently influenced obstructive indexes. CONCLUSION The bronchial wall attenuation value is a powerful index for assessing tobacco-related bronchial wall changes in patients with COPD.

Remote Ischemic Preconditioning and Contrast-Induced Nephropathy: A Systematic Review

BACKGROUND The use of imaging is increasing in clinical practice either for diagnosis or intervention. In these aims, contrast medium (CM) is widely used. However, CM administration can induce contrast-induced nephropathy (CIN). The incidence of CIN varies from 2% to 50% depending on patient risk factors, and CIN is the third cause of renal insufficiency. To date, methods such as hyperhydration to prevent CIN have a low level of evidence. Remote ischemic preconditioning (RIPC), which has already proved its efficiency in the cardiology field, seems to be a promising technique for CIN prevention. The aim of this work was to carry out a systematic review of the literature of the randomized clinical studies on RIPC in the prevention of CIN in man. METHODS We conducted a systematic review of randomized clinical studies on the RIPC in the prevention of CIN in man. Documentary sources were PubMed articles published until June 2015. Randomized clinical trials of RIPC in preventing CIN in human were reviewed. RESULTS Five articles were selected for the analysis. One article studied the impact of RIPC in a population at high risk of CIN, whereas the other 4 analyzed populations at low, moderate or unknown risk of CIN. In 4 studies, except the later one, the risk of CIN was based on the Mehran score that was previously published. In the high-risk population, a decrease in the incidence of CIN was found in the RIPC group compared with the control group (12% against 40%; P = 0.002). Among the 3 other studies using the Mehrans score, one also demonstrated the interest of such a procedure in a subgroup of high-risk patients. A second one found a low incidence of CIN in the RIPC group ([5 of 47; 10%] as compared with a control group [17 of 47; 36%] P = 0.003) in patients at the low risk of CIN. In another low-risk population, a significant lower level of a biological marker (liver-type fatty acid-binding protein) that assesses a renal impairment was found in the RIPC compared with the control group. CONCLUSIONS Only 5 studies were found in this search, which may constitute a limitation. However, RIPC appears as a promising method to prevent CIN since it is a noninvasive, low cost, easy, and safe method. More randomized controlled trials are needed to confirm these preliminary results.

In vivo MR imaging of pulmonary arteries of normal and experimental emboli in small animals.

To demonstrate the feasibility of pulmonary MRA in living rodents.

Left ventricular non-compaction and idiopathic dilated cardiomyopathy: the significant diagnostic value of longitudinal strain

Left ventricular non-compaction (LV NC) is characterized by abnormal trabeculations that are mainly at the LV apex. Distinction between LV NC and non-specific dilated cardiomyopathies (DCMs) remains often challenging. We sought to find additive tools comparing the longitudinal strain characteristics of LVNC versus idiopathic DCM in a cohort of patients. 48 cases of LVNC (derivation cohort) were compared with 45 cases of DCM. Global and regional multi-layer (sub-endocardial, mid-wall, and sub-epicardial) LV longitudinal strain analysis was performed. Results were compared to define the best tool for distinguishing LVNC from DCM. A validation cohort (41 LVNC patients) was then used to assess the performance of the proposed diagnostic tools. In the derivation cohort, longitudinal deformation (strain) was greater in LVNC than in DCM patients. Longitudinal shortening was greater in the non-compacted segments than in the compacted ones. A mid-wall strain base-apex gradient had 88.4 % sensitivity and 66.7 % specificity in distinguishing LVNC from DCM (AUC = 0.83; cut-off of −23 or |0.23|%). In a multivariable model, the base-apex mid-wall gradient in an apical 4-chamber view was the only independent echocardiographic criteria (OR = 0.76, CI 95 % [0.66; 0.90], p = 0.0010) allowing the distinction between LVNC and DCM. In the validation cohort, the base-apex mid-wall gradient of strain had 88.4 % sensitivity, 85.7 % negative predictive values for the diagnosis of LVNC. Longitudinal strain, especially the base-apex longitudinal gradient of strain, appears as an additive valuable tool for distinguishing LVNC from DCM.

Haemodynamically proven pulmonary hypertension in a patient with GATA2 deficiency-associated pulmonary alveolar proteinosis and fibrosis

Over the past few years, genetics has significantly improved the understanding of interstitial lung diseases (ILD). For example, in idiopathic pulmonary fibrosis, telomerase complex mutations have been shown to drive a specific phenotype including haematological, liver and cutaneous abnormalities [1]. Recently, GATA2 deficiency has been associated with a broad phenotype including haematological, vascular, infectious and pulmonary diseases [2–4]. GATA2 is a zinc finger transcription factor essential for differentiation of immature haematopoietic cells. Among many other functions, GATA2 regulates the phagocytosis of alveolar macrophages. Therefore, alveolar macrophage dysfunction is thought to be the pathophysiological basis for the occurrence of pulmonary alveolar proteinosis, the main lung condition in GATA2 deficiency [4]. However, pulmonary alveolar proteinosis associated with GATA2 deficiency does not share the same clinical, biological or radiological features as autoimmune pulmonary alveolar proteinosis. In all cases of GATA2 deficiency-associated pulmonary alveolar proteinosis reported in the literature, granulocyte–macrophage colony-stimulating factor (GM-CSF) antibodies were absent [2, 4]. Moreover, other pulmonary diseases such as fibrosis or pulmonary hypertension (PH) have been reported to occur in GATA2 deficiency [4], suggesting that the precise pathophysiological mechanisms are not fully understood. Pulmonary fibrosis may be more prevalent in adults with GATA2 deficiency due to a longer duration of the disease http://ow.ly/WHnu30aCZ4S

Multi-modal data fusion for Cardiac Resynchronization Therapy planning and assistance

Cardiac Resynchronization Therapy (CRT) has been validated as an efficient treatment for selected patients suffering from heart failure with cardiac dyssynchrony. In case of bi-ventricular stimulation, the response to the therapy may be improved by an optimal choice of the left ventricle (LV) pacing sites. The characterization of LV properties to select the best candidate sites and to precise their access modes would be useful for the clinician in pre- and per-operative stages. For that purpose, we propose a new pre-operative analysis solution integrating previously developed multi-modal data registration methods and a new segmentation process of their coronary venous access. Moreover, a novel visualization interface is proposed to help the clinician to visualize the most relevant pacing sites and their access during the implantation in the operating room. This work is illustrated on real CRT data patients.

Edge-preserving denoising for intra-operative cone beam CT in endovascular aneurysm repair

C-arm cone-beam computed tomography (CBCT) acquisition during endovascular aneurysm repair (EVAR) is an emergent technology with more and more applications. It offers real time imaging with a stationary patient and provides 3-D information to achieve guidance of intervention. However, there is growing concern on the overall radiation doses delivered to patients all along the endovascular management due to pre-, intra-, and post-operative X-ray imaging. Manufactures may have their low dose protocols to realize reduction of radiation dose, but CBCT with a low dose protocol has too many artifacts, particularly streak artifacts, and decreased contrast-to-noise ratio (CNR). To reduce noise and artifacts, a penalized weighted least-squares (PWLS) algorithm with an edge-preserving penalty is proposed. The proposed method is evaluated by quantitative parameters including a defined signal-to-noise ratio (SNR), CNR, and modulation transfer function (MTF) on clinical CBCT. Comparisons with PWLS algorithms with isotropic, TV, Huber, anisotropic penalties demonstrate that the proposed edge-preserving penalty performs well not only on edge preservation, but also on streak artifacts suppression, which may be crucial for observing guidewire and stentgraft in EVAR.