Younes Arous

Interpretation of cardiac wall motion from cine-MRI combined with parametric imaging based on the Hilbert transform

ObjectThe aim of this study was to test and validate the clinical impact of parametric amplitude images obtained using the Hilbert transform on the regional interpretation of cardiac wall motion abnormalities from cine-MR images by non-expert radiologists compared with expert consensus.Materials and methodsCine-MRI short-axis images obtained in 20 patients (10 with myocardial infarction, 5 with myocarditis and 5 with normal function) were processed to compute a parametric amplitude image for each using the Hilbert transform. Two expert radiologists blindly reviewed the cine-MR images to define a gold standard for wall motion interpretation for each left ventricular sector. Two non-expert radiologists reviewed and graded the same images without and in combination with parametric images. Grades assigned to each segment in the two separate sessions were compared with the gold standard.ResultsAccording to expert interpretation, 264/320 (82.5%) segments were classified as normal and 56/320 (17.5%) were considered abnormal. The accuracy of the non-expert radiologists’ grades compared to the gold standard was significantly improved by adding parametric images (from 87.2 to 94.6%) together with sensitivity (from 64.29 to 84.4%) and specificity (from 92 to 96.9%), also resulting in reduced interobserver variability (from 12.8 to 5.6%).ConclusionThe use of parametric amplitude images based on the Hilbert transform in conjunction with cine-MRI was shown to be a promising technique for improvement of the detection of left ventricular wall motion abnormalities in less expert radiologists.

Multimodality imaging assessment of a caseous calcification of the mitral valve annulus

Caseous calcification of the mitral annulus (CCMA) is a rare echocardiographic finding. It is commonly misdiagnosed as an abscess, tumor or infective vegetation on the mitral valve. Since it is a benign process, differentiating it from malignant intra-cardiac mass is primordial to avoid unnecessary surgery. Various imaging modalities can be complimentary for definitive diagnosis. We present a case of CCMA in a 71-year-old female patient. Her medical history revealed hypertension, diabetes mellitus, hyperlipidaemia and coronary artery disease. She was referred to our department for coronary catheterization because of angina symptoms upon minimal exertion. The lesion was detected during echocardiography and was defined as a mass of heterogeneous content with calcification points, located at the posterior side of the mitral valve annulus. Restricted motion of the posterior leaflet and the mass effect caused only minimal mitral regurgitation. To establish the correct diagnosis, we performed the full spectrum of noninvasive cardiac imaging modalities. Transesophageal echocardiography identified well-organized, composite lesion with regular edges, markedly calcified margins and more echolucent central portion. A computed tomography (CT) was performed, showing a hyperdense mass with hypodense center and a calcified peripheral rim located at the posterior mitral ring. Cardiac magnetic resonance imaging (MRI) showed that the mass was hypointense with respect to the myocardium in the T1 and T2-weighted sequences and only presented late-phase enhancement in the surrounding capsule. Based on the CT and MRI findings, the diagnosis of CCMA was established. The patient was managed conservatively.

Comparison between 3D Echocardiography and Cardiac Magnetic Resonance Imaging (CMRI) in the measurement of Left Ventricular Volumes and Ejection Fraction

BACKGROUND Echocardiography and Cardiac Magnetic Resonance Imaging (CMRI) are two noninvasive techniques for the evaluation of cardiac function for patients with coronary artery diseases. Although echocardiography is the commonly used technique in clinical practice for the assessment of cardiac function, the measurement of LV volumes and left ventricular ejection fraction (LVEF) by the use of this technique is still influenced by several factors inherent to the protocol acquisition, which may affect the accuracy of echocardiography in the measurement of global LV parameters. OBJECTIVE The aim of this study is to compare the end systolic volume (ESV), the end diastolic volume (EDV), and the LVEF values obtained with three dimensional echocardiography (3D echo) with those obtained by CMRI (3 Tesla) in order to estimate the accuracy of 3D echo in the assessment of cardiac function. METHODS 20 subjects, (9 controls, 6 with myocardial infarction, and 5 with myocarditis) with age varying from 18 to 58, underwent 3D echo and CMRI. LV volumes and LVEF were computed from CMRI using a stack of cine MRI images in a short axis view. The same parameters were calculated using the 3D echo. A linear regression analysis and Bland Altman diagrams were performed to evaluate the correlation and the degree of agreement between the measurements obtained by the two methods. RESULTS The obtained results show a strong correlation between the 3D echo and CMR in the measurement of functional parameters (r = 0.96 for LVEF values, r = 0.99 for ESV and r= 0.98 for EDV, p < 0.01 for all) with a little lower values of LV volumes and higher values of LVEF by 3D echo compared to CMRI. According to statistical analysis, there is a slight discrepancy between the measurements obtained by the two methods. CONCLUSION 3D echo represents an accurate noninvasive tool for the assessment of cardiac function. However, other studies should be conducted on a larger population including some complicated diagnostic cases.

Parametric Imaging for the Assessment of Cardiac Motion: A Review

The assessment of wall motion abnormalities such as hypokinesia or dyskinesia and the identification of their extent as well as their degree of severity allow an accurate evaluation of several ischemic heart diseases and an early diagnosis of heart failure. These dysfunctions are usually revealed by a drop of contraction indicating a regional hypokinesia or a total absence of the wall motion in case of akinesia. The discrimination between these contraction abnormalities plays also a significant role in the therapeutic decision through the differentiation between the infarcted zones, which have lost their contractile function, and the stunned areas that still retain viable myocardial tissues. The lack of a reliable method for the evaluation of wall motion abnormalities in cardiac imaging presents a major limitation for a regional assessment of the left ventricular function. In the past years, several techniques were proposed as additional tools for the local detection of wall motion deformation. Among these approaches, the parametric imaging is likely to represent a promising technique for the analysis of a local contractile function. The aim of this paper is to review the most recent techniques of parametric imaging computation developed in cardiac imaging and their potential contributions in clinical practice.

The Role of PHASE IMAGE in the Detection of Myocardial Dyskinesia by Magnetic Resonance Imaging (MRI)

BACKGROUND The assessment of cardiac wall motion abnormalities plays an important role in the evaluation of many cardiovascular diseases and the prediction of functional recovery. Most of the methods dedicated to identifying the location of wall motion abnormalities have been restricted to study hypokinesia while an accurate way to assess dyskinesia is still needed in Cardiac Magnetic Resonance Imaging (CMRI). OBJECTIVE The aim of this study is to propose a phase image based on the analytic signal able to assess the extent of the myocardial dyskinetic segments in Cardiac Magnetic Resonance Imaging (CMRI). MATERIALS 22 subjects were retrospectively enrolled in this study (age 46 ± 11): 15 presenting an aneurysm and 7 control subjects with normal wall motion. For each patient, three standard views (short axis view, 2 chamber and 4 chamber views) were acquired using 3 Tesla Siemens Avanto MRI scanner and a segmented True FISP sequence. All the cine MRI images were analyzed by two experimented observers who were blinded to the diagnostic results. RESULTS The outcomes of this study show that using the proposed phase image in MRI clinical routine can increase the accuracy of the detection of myocardial dyskinetic segments from 77.23 % to 86.38 %, the sensitivity from 67.48 % to 78.86 % as well the specificity from 80.92 % to 89.23 % compared to the standard method based on cine MRI interpretation. CONCLUSION The phase image is a promising tool in CMRI for the assessment of dyskinetic segments and the degree of myocardial asynchronism.

Keys for reporting an fMRI in motor control study

an olfactory discrimination test is performed. During the juvenile period, behavioral tests assessing exploration (Open field at P15, 20, 25), sensorimotor gating (Prepulse inhibition (PPI) at P35), and social interactions assessments (at P40) were used to detect behavioral impairments. Brains were removed at P40 for neuropathological studies (MRI, immunohistochemical studies and electron microscopy studies). Results: Brain damage featured lateral ventricles widening, predominately in male, reduction of periventricular external capsules thickness, oligodendrocyte loss, and disorganization of fronto-parietal sub-cortical tissue without any persistant glial proliferation. Autistic hallmarks were found in offspring exposed to GBS, namely deficits in exploratory behavior, social and communicative impairments, i.e. profound defects in the integration and response to both acoustic (PPI) and chemical signals (nest-seeking test) that are predominant modes of communication in rats. Surprisingly, only male offspring were affected by these combined autistic-like traits. Discussion: Our results show for the first time that maternofetal inflammatory response to GBS plays a role in the induction of cerebral insults, remarkably recapitulating cardinal features of human autism, such as gender dichotomy and neurobehavioral traits. These results also provide important evidence that beyond genetic influences, modifiable environmental factors play a role in both the occurrence of autism, and in its gender imbalance.

OA18 De l’aspect en IRM a la comprehension de la physiopathologie des spondylodiscites chez l’adulte

Objectifs Il s’agit d’expliquer a posteriori le mode de contamination et de migration des coulees infectieuses a l’aide de certaines images IRM typiques. Materiels et methodes Revue retrospective d’une serie de six dossiers IRM de spondylodiscites de natures variees parmi 36 observations, afin de rechercher des stigmates ou signes expliquant les donnees theoriques de la physiopathologie des spondylodiscites. Resultats L’atteinte infectieuse recherchee au niveau du coin anterieur de la vertebre, du ligament vertebral commun anterieur, du disque, de l’espace epidural et des parties molles perivertebrales a permis un tres bonne correlation avec les donnees physiopathologiques mais elle n’est pas retrouvee a tous les coups. La migration transversale ou longitudinale est variable d’un germe a un autre et pour un meme germe et une meme localisation rachidienne d’un patient a un autre. Conclusion Certains aspects morphologiques des spondylodiscites sont tres evocateurs voire specifiques de l’etiologie d’une spondylodiscite, mais ne sont pas constants. Le delai de realisation de l’examen jouerait un role.