All you need to know about the tricuspid valve: Tricuspid valve imaging and tricuspid regurgitation analysis

SummaryThe acknowledgment of tricuspid regurgitation (TR) as a stand-alone and progressive entity, worsening the prognosis of patients whatever its aetiology, has led to renewed interest in the tricuspid-right ventricular complex. The tricuspid valve (TV) is a complex, dynamic and changing structure. As the TV is not easy to analyse, three-dimensional imaging, cardiac magnetic resonance imaging and computed tomography scans may add to two-dimensional transthoracic and transoesophageal echocardiographic data in the analysis of TR. Not only the severity of TR, but also its mechanisms, the mode of leaflet coaptation, the degree of tricuspid annulus enlargement and tenting, and the haemodynamic consequences for right atrial and right ventricular morphology and function have to be taken into account. TR is functional and is a satellite of left-sided heart disease and/or elevated pulmonary artery pressure most of the time; a particular form is characterized by TR worsening after left-sided valve surgery, which has been shown to impair patient prognosis. A better description of TV anatomy and function by multimodality imaging should help with the appropriate selection of patients who will benefit from either surgical TV repair/replacement or a percutaneous procedure for TR, especially among patients who are to undergo or have undergone primary left-sided valvular surgery

First attempt to motion corrected flow encoding using free-breathing phase-contrast CINE MRI

International audienceThis study demonstrates the feasibility of free-breathing phase-contrast CINE MRI without averaging. A new version of the CINE GRICS algorithm[1] was used to correct for motion

Segmentation fonctionnelle de séquences d'IRM rénales à rehaussement de contraste par quantification vectorielle

En Imagerie par Résonance Magnétique (IRM) à rehaussement de contraste, la segmentation des structures internes du rein est nécessaire pour une étude de la fonction rénale par compartiment. Pour éviter une segmentation manuelle fastidieuse, deux méthodes (semi-)automatiques, utilisant un algorithme de quantification vectorielle visant à regrouper les pixels rénaux d'après leurs vecteurs temps-intensité, sont proposées et validées sur des données réelles

Myocardial deformation in malignant mitral valve prolapse: A shifting paradigm to dynamic mitral valve–ventricular interactions

ObjectivesThis study sought to assess the value of myocardial deformation using strain echocardiography in patients with mitral valve prolapse (MVP) and severe ventricular arrhythmia and to evaluate its impact on rhythmic risk stratification.BackgroundMVP is a common valvular affection with an overly benign course. Unpredictably, selected patients will present severe ventricular arrhythmia.MethodsPatients with MVP as the only cause of aborted SCD (MVP-aSCD: ventricular fibrillation and monomorphic and polymorphic ventricular tachycardia) with no other obvious reversible cause were identified. Nonconsecutive patients referred for the echocardiographic evaluation of MVP were enrolled as a control cohort and dichotomized according to the presence or absence of premature ventricular contractions (MVP-PVC or MVP-No PVC, respectively). All patients had a comprehensive strain assessment of mechanical dispersion (MD), postsystolic shortening, and postsystolic index (PSI).ResultsA total of 260 patients were enrolled (20 MVP-aSCD, 54 MVP-PVC, and 186 MVP-No PVC). Deformation pattern discrepancies were observed with a higher PSI value in MVP-aSCD than that in MVP-PVC (4.6 ± 2.0 vs. 2.9 ± 3.7, p = 0.014) and a higher MD value than that in MVP-No PVC (46.0 ± 13.0 vs. 36.4 ± 10.8, p = 0.002). In addition, PSI and MD increased the prediction of severe ventricular arrhythmia on top of classical risk factors in MVP. Net reclassification improvement was 61% (p = 0.008) for PSI and 71% (p = 0.001) for MD.ConclusionsIn MVP, myocardial deformation analysis with strain echocardiography identified specific contraction patterns with postsystolic shortening leading to increased values of PSI and MD, translating the importance of mitral valve–myocardial interactions in the arrhythmogenesis of severe ventricular arrhythmia. Strain echocardiography may provide important implications for rhythmic risk stratification in MVP

Functional Semi-Automated Segmentation of Renal DCE-MRI Sequences

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.International audienceIn dynamic contrast-enhanced magnetic resonance imaging (DCE- MRI), segmentation of internal kidney structures is essential for functional evaluation. Manual morphological segmentation of cortex, medulla and cavities remains difficult and time- consuming especially because the different renal compartments are hard to distinguish on a single image. We propose to test a semi-automated method to segment internal kidney structures from a DCE-MRI registered sequence. As the temporal intensity evolution is different in each of the three kidney compartments, pixels are sorted according to their time- intensity curves using a k-means partitioning algorithm. No ground truth is available to evaluate resulting segmentations so a manual segmentation by a radiologist is chosen as a reference. We first evaluate some similarity criteria between the functional segmentations and this reference. The same measures are then computed between another manual segmentation and the reference. Results are similar for the two types of comparisons

Functional Semi-Automated Segmentation of Renal DCE-MRI Sequences Using a Growing Neural Gas algorithm

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Free-breathing myocardial T2 measurements at 1.5T

POSTER PRESENTATIONInternational audienc