Real time flow with fast GPU reconstruction for continuous assessment of cardiac output

A novel approach for continuous cardiac output quantification during an exercise was developed and implemented on a heterogeneous image reconstruction system. Combination of spiral real-time PCMR sequence with parallel imaging allowed on high-temporal acquisition. Application of a GPU for image processing resulted in almost instantaneous reconstruction. An external computer equipped with the GPU was networked using CORBA technology. This let on seamless processing from a clinician point of view. The implementation was tested and validated against our multi -core CP

A multimodal real-time MRI articulatory corpus of French for speech research

In this work we describe the creation of ArtSpeechMRIfr: a real-time as well as static magnetic resonance imaging (rtMRI, 3D MRI) database of the vocal tract. The database contains also processed data: denoised audio, its phonetically aligned annotation, articulatory contours, and vocal tract volume information , which provides a rich resource for speech research. The database is built on data from two male speakers of French. It covers a number of phonetic contexts in the controlled part, as well as spontaneous speech, 3D MRI scans of sustained vocalic articulations, and of the dental casts of the subjects. The corpus for rtMRI consists of 79 synthetic sentences constructed from a phonetized dictionary that makes possible to shorten the duration of acquisitions while keeping a very good coverage of the phonetic contexts which exist in French. The 3D MRI includes acquisitions for 12 French vowels and 10 consonants, each of which was pronounced in several vocalic contexts. Ar-ticulatory contours (tongue, jaw, epiglottis, larynx, velum, lips) as well as 3D volumes were manually drawn for a part of the images

Real time magnetic resonance assessment of septal curvature accurately tracks acute hemodynamic changes in pediatric pulmonary hypertension

International audienceBACKGROUND:This study assesses the relationship between septal curvature and mean pulmonary artery pressure and indexed pulmonary vascular resistance in children with pulmonary hypertension. We hypothesized that septal curvature could be used to estimate right ventricular afterload and track acute changes in pulmonary hemodynamics.METHODS AND RESULTS:Fifty patients with a median age of 6.7 years (range, 0.45-16.5 years) underwent combined cardiac catheterization and cardiovascular magnetic resonance. The majority had idiopathic pulmonary arterial hypertension (n=30); the remaining patients had pulmonary hypertension associated with repaired congenital heart disease (n=17) or lung disease (n=3). Mean pulmonary artery pressure and pulmonary vascular resistance were acquired at baseline and during vasodilation. Septal curvature was measured using real-time cardiovascular magnetic resonance. There was a strong correlation between mean pulmonary artery pressure and SCmin at baseline and during vasodilator testing (r=-0.81 and -0.85, respectively; P<0.01). A strong linear relationship also existed between pulmonary vascular resistance and minimum septal curvature indexed to cardiac output both at baseline and during vasodilator testing (r=-0.88 and -0.87, respectively; P<0.01). Change in septal curvature metrics moderately correlated with absolute change in mean pulmonary artery pressure and pulmonary vascular resistance, respectively (r=0.58 and -0.74; P<0.01). Septal curvature metrics were able to identify vasoresponders with a sensitivity of 83% (95% confidence interval, 0.36-0.99) and a specificity of 91% (95% confidence interval, 0.77-0.97), using the Sitbon criteria. Idiopathic pulmonary arterial hypertension subgroup analysis revealed 3 responders with ΔSCmin values of 0.523, 0.551, and 0.568. If the middle value of 0.551 is taken as a cutoff, the approximate sensitivity would be 67% and the specificity would be 93%.CONCLUSIONS:Septal curvature metrics are able to estimate right ventricular afterload and track acute changes in pulmonary hemodynamics during vasodilator testing. This suggests that septal curvature could be used for continuing assessment of load in pulmonary hypertension

Dual registration of abdominal motion for motility assessment in free-breathing data sets acquired using dynamic MRI.

At present, registration-based quantification of bowel motility from dynamic MRI is limited to breath-hold studies. Here we validate a dual-registration technique robust to respiratory motion for the assessment of small bowel and colonic motility. Small bowel datasets were acquired in breath-hold and free-breathing in 20 healthy individuals. A pre-processing step using an iterative registration of the low rank component of the data was applied to remove respiratory motion from the free breathing data. Motility was then quantified with an existing optic-flow (OF) based registration technique to form a dual-stage approach, termed Dual Registration of Abdominal Motion (DRAM). The benefit of respiratory motion correction was assessed by (1) assessing the fidelity of automatically propagated segmental regions of interest (ROIs) in the small bowel and colon and (2) comparing parametric motility maps to a breath-hold ground truth. DRAM demonstrated an improved ability to propagate ROIs through free-breathing small bowel and colonic motility data, with median error decreased by 90% and 55%, respectively. Comparison between global parametric maps showed high concordance between breath-hold data and free-breathing DRAM. Quantification of segmental and global motility in dynamic MR data is more accurate and robust to respiration when using the DRAM approach

Super-résolution multi-images en IRM par approximation de Tucker couplée

International audience-Ce papier résout le problème de super-résolution à partir de plusieurs images IRM. Le problème de reconstruction est formulé comme une approximation multilinéaire tensorielle couplée. Nos résultats théoriques prouvent qu'il est possible de reconstruire exactement l'image à haute résolution. Nous proposons également un algorithme simple basé sur une régularisation de Tikhonov. Nos simulations sur données réelles illustrent les performances de cette approche, à un coût de calcul réduit par rapport à l'état de l'art

MULTI-FRAME SUPER-RESOLUTION MRI USING COUPLED LOW-RANK TUCKER APPROXIMATION

In this paper, we address the multi-frame super-resolution MRI problem. We formulate the reconstruction problem as a coupled tensor multilinear approximation. We prove that exact recovery of the high-resolution 3D isotropic image is achievable for a variety of multilinear ranks. We propose a simple algorithm based on Tikhonov regularization to perform the reconstruction. Our simulations on real datasets illustrates the good performance of the proposed approach, with a lower computation time than state-of-the-art methods

Super-resolution reconstruction of brain 3D magnetic resonance images using a coupled tensor multilinear approximation

In this paper, we address the multi-frame superresolution MRI problem. We formulate the reconstruction problem as a coupled tensor multilinear approximation. We prove that exact recovery of the high-resolution 3D isotropic image is achievable for a variety of multilinear ranks. We propose a simple algorithm based on Tikhonov regularization to perform the reconstruction. Our simulations on real datasets illustrates the good performance of the proposed approach, with a lower computation time than state-of-the-art methods

MULTI-FRAME SUPER-RESOLUTION MRI USING COUPLED LOW-RANK TUCKER APPROXIMATION

In this paper, we address the multi-frame super-resolution MRI problem. We formulate the reconstruction problem as a coupled tensor multilinear approximation. We prove that exact recovery of the high-resolution 3D isotropic image is achievable for a variety of multilinear ranks. We propose a simple algorithm based on Tikhonov regularization to perform the reconstruction. Our simulations on real datasets illustrates the good performance of the proposed approach, with a lower computation time than state-of-the-art methods

Parathyroid hemangioma

Background: Hemangiomas are benign neoplasms of capillary proliferation that arise from a developmental anomaly where angioblastic mesenchyme fails to form canals. Most hemangiomas arise in the head and neck region, either superficially in the skin or deeper within endocrine organs such as the parotid gland. Parathyroid hemangiomas, however, are extremely rare, with only five cases previously reported in the literature. Case presentation: Herein, we present a case of a 68-year-old man with a hemangioma almost completely replacing the right upper parathyroid gland, grossly measuring 1.3 × 1.3 × 1.2 cm and weighing 700 mg, associated with primary hyperparathyroidism. Conclusions: Parathyroid gland enlargement due to vascular neoplasms such as hemangiomas can mimic, both clinically and radiographically, hyperplasias and/or adenomas. Surgeons need to be aware of the presence of this entity and should consider it in the differential diagnosis of hyperparathyroidism or parathyroid gland enlargement

Respiratory motion correction in whole body PET/MRI imaging using a generalized reconstruction by inversion of coupled systems (GRICS) approach

International audienc