162 research outputs found

    In-vivo assessment of normal T1 values of the right-ventricular myocardium by cardiac MRI

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    To test feasibility of myocardial T1 mapping of the right ventricle (RV) at systole when myocardium is more compact and to determine the most appropriate imaging plane. 20 healthy volunteers (11 men; 33±8years) were imaged on a 1.5T scanner (MAGNETOM Avanto, Siemens AG, Erlangen, Germany). A modified look-locker inversion-recovery sequence was acquired at mid-ventricular short axis (SAX), as horizontal long-axis view and as transversal view at systole (mean trigger time 363±37ms). Myocardial T1 time of the left-ventricular and RV myocardium was measured within a region of interest (ROI) on generated T1-maps. The most appropriate imaging plane for the RV was determined by the ability to draw a ROI including the largest amount of myocardium without including adjacent tissue or blood. At systole, when myocardium is thicker, measurements of the RV myocardium were feasible in 18/20 subjects. Average size of the ROI was 0.42±0.28cm2. In 10/18 subjects, short axis was the most appropriate imaging plane to obtain measurements (p=0.034). Average T1 time of the RV myocardium was 1,016±61ms, and average T1 of the left-ventricular (LV) was 956±25ms (p<0.001). T1 mapping of the RV myocardium is feasible during systole in the majority of healthy subjects but with a small ROI only. SAX plane was the optimal imaging plane in the majority of subjects. Native myocardial T1 time of the RV is significantly longer compared to the LV, which might be explained by the naturally higher collagen content of the RV

    Functional results after chest wall stabilization with a new screwless fixation device

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    OBJECTIVES This is the experience with the Stratos system in two surgical centres for the management of two types of rib fractures: flail chest and multiple dislocated rib fractures with significant chest wall deformity. METHODS From January 2009 to May 2012, 94 consecutive patients were included. Selected indications were extended anterolateral flail chest (n = 68) and dislocated painful rib fractures (n = 26). The open reduction internal fixation (ORIF) system consists of flexible titanium rib clamps and connecting plates. The postoperative course was assessed. Clinical and functional outcomes were evaluated at 6 months. Functional assessment consisted of measurement of the functional vital capacity (FVC) and magnetic resonance imaging (MRI) examination with determination of the radiological vital capacity (rVC) in patients with a flail chest. RESULTS The median operation time and length of hospital stay were 122 min and 19 days, respectively, in patients with a flail chest, and 67 min and 11 days, respectively, in patients with dislocated painful rib fractures. The morbidity rate was 6.4% and the overall 30-day mortality rate was 1.1%. Clinical evaluation and pulmonary function testing at 6 months revealed no deformity of the chest wall, symmetrical shoulder girdle mobility in 88% and a feeling of stiffness on the operated side in 19% of the patients operated for a flail chest. Median ratio of FVC was 88%, not suggesting any restriction after stabilization. MRI was performed in 53% (36 of 68) of the patients with a flail chest. The analysis of the rVC showed, on average, no clinically relevant restriction related to the operation, with a mean rVC of the operated relative to the non-operated side of 92% (95% confidence interval: 83, 100). Stabilization of more than four ribs was associated with a lower median rVC than stabilization of four or less ribs. CONCLUSIONS Our results suggest that stabilization of the chest wall with this screwless rib fixation device can be performed with a low morbidity and lead to early restoration of chest wall integrity and respiratory pump function, without clinically relevant functional restriction. Owing to the simplicity of the fixation technique, indications for stabilization can be safely enlarged to selected patients with dislocated and painful rib fracture

    Reference ranges ("normal values") for cardiovascular magnetic resonance (CMR) in adults and children: 2020 update

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    Cardiovascular magnetic resonance (CMR) enables assessment and quantification of morphological and functional parameters of the heart, including chamber size and function, diameters of the aorta and pulmonary arteries, flow and myocardial relaxation times. Knowledge of reference ranges ("normal values") for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. Compared to the previous version of this review published in 2015, we present updated and expanded reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques. Further, databases and references for deep learning methods are included

    3T MRI investigation of cardiac left ventricular structure and function in a UK population:The tayside screening for the prevention of cardiac events (TASCFORCE) study

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    Contract grant sponsor: Souter Charitable Trust, and Chest, Heart and Stroke Scotland; Contract grant sponsor: Wellcome Trust; contract grant number: WT 085664 (Clinical Research Fellowship to J.W-McC.)Purpose : To scan a volunteer population using 3.0T magnetic resonance imaging (MRI). MRI of the left ventricular (LV) structure and function in healthy volunteers has been reported extensively at 1.5T. Materials and Methods : A population of 1528 volunteers was scanned. A standardized approach was taken to acquire steady-state free precession (SSFP) LV data in the short-axis plane, and images were quantified using commercial software. Six observers undertook the segmentation analysis. Results : Mean values (±standard deviation, SD) were: ejection fraction (EF) = 69 ± 6%, end diastolic volume index (EDVI) = 71 ± 13 ml/m2 , end systolic volume index (ESVI) = 22 ± 7 ml/m2 , stroke volume index (SVI) = 49 ± 8 ml/m2 , and LV mass index (LVMI) = 55 ± 12 g/m2 . The mean EF was slightly larger for females (69%) than for males (68%), but all other variables were smaller for females (EDVI 68v77 ml/m2 , ESVI 21v25 ml/m2 , SVI 46v52 ml/m2 , LVMI 49v64 g/m2, all P < 0.05). The mean LV volume data mostly decreased with each age decade (EDVI males: -2.9 ± 1.3 ml/m2 , females: -3.1 ± 0.8 ml/m2 ; ESVI males: -1.3 ± 0.7 ml/m2 , females: -1.7 ± 0.5 ml/m2 ; SVI males: -1.7 ± 0.9 ml/m2 , females: -1.4 ± 0.6 ml/m2 ; LVMI males: -1.6 ± 1.1 g/m2 , females: -0.2 ± 0.6 g/m2 but the mean EF was virtually stable in males (0.6 ± 0.6%) and rose slightly in females (1.2 ± 0.5%) with age. Conclusion : LV reference ranges are provided in this population-based MR study at 3.0T. The variables are similar to those described at 1.5T, including variations with age and gender. These data may help to support future population-based MR research studies that involve the use of 3.0T MRI scanners.Publisher PDFPeer reviewe

    Hypertrabeculated Left Ventricular Myocardium in Relationship to Myocardial Function and Fibrosis: The Multi-Ethnic Study of Atherosclerosis

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    This research was supported by contracts N01-HC-95159, N01-HC-95160, N01-HC-95161, N01- HC-95162, N01-HC-95163, N01-HC-95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC- 95168 and N01-HC-95169 from the National Heart, Lung, and Blood Institute, by grants UL1-TR-000040 and UL1-TR-001079 from NCRR, and by a grant from Bayer Healthcare for the use of gadolinium contrast agent. G.C. is supported by the National Institute for Health Research Rare Diseases Translational Research Collaboration (NIHR RD-TRC). J.C.M. is directly and indirectly supported by the University College London Hospitals NIHR Biomedical Research Centre and Biomedical Research Unit at Barts Hospital, respectively
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