Comparison of two deep-learning image reconstruction algorithms on cardiac CT images: A phantom study.

PURPOSE: The purpose of this study was to compare the performance of Precise IQ Engine (PIQE) and Advanced intelligent Clear-IQ Engine (AiCE) algorithms on image-quality according to the dose level in a cardiac computed tomography (CT) protocol. MATERIALS AND METHODS: Acquisitions were performed using the CT ACR 464 phantom at three dose levels (volume CT dose indexes: 7.1/5.2/3.1 mGy) using a prospective cardiac CT protocol. Raw data were reconstructed using the three levels of AiCE and PIQE (Mild, Standard and Strong). The noise power spectrum (NPS) and task-based transfer function (TTF) for bone and acrylic inserts were computed. The detectability index (d') was computed to model the detectability of the coronary lumen (350 Hounsfield units and 4-mm diameter) and non-calcified plaque (40 Hounsfield units and 2-mm diameter). RESULTS: Noise magnitude values were lower with PIQE than with AiCE (-13.4 ± 6.0 [standard deviation (SD)] % for Mild, -20.4 ± 4.0 [SD] % for Standard and -32.6 ± 2.6 [SD] % for Strong levels). The average NPS spatial frequencies shifted towards higher frequencies with PIQE than with AiCE (21.9 ± 3.5 [SD] % for Mild, 20.1 ± 3.0 [SD] % for Standard and 12.5 ± 3.5 [SD] % for Strong levels). The TTF values at fifty percent (f50) values shifted towards higher frequencies with PIQE than with AiCE for acrylic inserts but, for bone inserts, f50 values were found to be close. Whatever the dose and DLR level, d' values of both simulated cardiac lesions were higher with PIQE than with AiCE. For the simulated coronary lumen, d' values were better by 35.1 ± 9.3 (SD) % on average for all dose levels for Mild, 43.2 ± 5.0 (SD) % for Standard, and 62.6 ± 1.2 (SD) % for Strong levels. CONCLUSION: Compared to AiCE, PIQE reduced noise, improved spatial resolution, noise texture and detectability of simulated cardiac lesions. PIQE seems to have a greater potential for dose reduction in cardiac CT acquisition.

Differential impact of local and regional aortic stiffness on left ventricular remodeling: a cardiovascular magnetic resonance study.

BACKGROUND: Left ventricular (LV) remodeling and aortic stiffness have independent predictive value for all causes and cardiovascular mortality. Because elastic properties of the arterial wall vary along the aortic pathway, we hypothesized that local and regional aortic stiffness could differently impact on LV remodeling. METHODS AND RESULTS: Regional aortic stiffness was determined from carotid-femoral pulse wave velocity (cfPWV) measured by aplanation tonometry. Aortic arch pulse wave velocity was measured by phase contrast cardiovascular magnetic resonance (CMR). Local stiffness was calculated in the ascending aorta pulse wave velocity (aaPWV) and descending aorta pulse wave velocity using central pulse pressure measurement, cine CMR acquisition, and surface change estimation. CMR LV remodeling was expressed as LV mass to end-diastolic volume ratio.We evaluated 146 study participants (41 ±â€Š15 years) free of overt cardiovascular disease. In stepwise multivariate regression analysis, cfPWV and aaPWV were significantly and independently correlated to mass to end-diastolic volume ratio (partial R = 0.07 and R = 0.10, respectively, all P < 0.005) after adjustment for age, sex, BMI, brachial mean blood pressure, and central pulse pressure. Descending aorta pulse wave velocity was correlated with mass to end-diastolic volume ratio to a lower extent (R = 0.04, P = 0.0115) and aortic arch pulse wave velocity was not independently associated with mass to end-diastolic volume ratio. CfPWV and aaPWV were both independently associated with mass to end-diastolic volume ratio, explaining 5 and 8% of mass to end-diastolic volume ratio variance, respectively. CONCLUSION: In study participants free of overt cardiovascular disease, stiffness of the ascending aorta representing the local proximal aortic function face to the LV and of the downstream aortic pathway assessed by cfPWV reflecting more advanced alterations of material properties involving the entire aorta, are independent determinants of LV remodeling after adjustment to age, BMI, mean blood pressure, and sex.

Management of septic shock in intermediate care unit.

BACKGROUND: While guidelines advocate goal-directed resuscitation based on timed bundles, the management of septic shock (SS) outside an ICU setting has been poorly studied in intermediate care units (IMCU). PATIENTS AND METHOD: We reviewed all cases of septic shock patients admitted to our IMCU between January 2013 and June 2014. The characteristics of sepsis, compliance of bundles, and outcomes were collected. The IMCU population was compared with the SS patients admitted to the ICU during the same period. The primary objective was to evaluate the feasibility of care in an IMCU. RESULTS: We treated 59 patients in the IMCU. Forty-three patients (73%) were fully managed in the IMCU and 16 patients (27%) were secondarily transferred to the ICU. In the first 3hours, the compliance to bundles was: blood cultures (95%), plasma lactate concentration (90%), vascular filling volume (1500ml (1000-2000)) and antibiotics (100%). A central venous line and an arterial catheter were inserted in 85% and 98.3% of the cases. At 24h, patients who were transferred to the ICU had higher lactate concentrations than the other patients (1.4±0.7mmol versus 2.9±3.4mmol; P=0.03). A 24 hours-SOFA score>4 was correlated with a transfer in ICU (OR 7,75 (95% CI 2.08-28,81; P=0.002)). CONCLUSIONS: Our work demonstrated the ability to manage SS patients solely in an IMCU. It showed that the SS resuscitation bundle can be successfully implemented outside the ICU. A lack of improvement at the 24th hour is associated with a transfer to the ICU.

Head-to-head comparison of the diagnostic performance of coronary computed tomography angiography and dobutamine-stress echocardiography in the evaluation of acute chest pain with normal ECG findings and negative troponin tests: A prospective multicenter study.

OBJECTIVE: To perform a head-to-head comparison of coronary CT angiography (CCTA) and dobutamine-stress echocardiography (DSE) in patients presenting recent chest pain when troponin and ECG are negative. METHODS: Two hundred seventeen patients with recent chest pain, normal ECG findings, and negative troponin were prospectively included in this multicenter study and were scheduled for CCTA and DSE. Invasive coronary angiography (ICA), was performed in patients when either DSE or CCTA was considered positive or when both were non-contributive or in case of recurrent chest pain during 6month follow-up. The presence of coronary artery stenosis was defined as a luminal obstruction >50% diameter in any coronary segment at ICA. RESULTS: ICA was performed in 75 (34.6%) patients. Coronary artery stenosis was identified in 37 (17%) patients. For CCTA, the sensitivity was 96.9% (95% CI 83.4-99.9), specificity 48.3% (29.4-67.5), positive likelihood ratio 2.06 (95% CI 1.36-3.11), and negative likelihood ratio 0.07 (95% CI 0.01-0.52). The sensitivity of DSE was 51.6% (95% CI 33.1-69.9), specificity 46.7% (28.3-65.7), positive likelihood ratio 1.03 (95% CI 0.62-1.72), and negative likelihood ratio 1.10 (95% CI 0.63-1.93). The CCTA: DSE ratio of true-positive and false-positive rates was 1.70 (95% CI 1.65-1.75) and 1.00 (95% CI 0.91-1.09), respectively, when non-contributive CCTA and DSE were both considered positive. Only one missed acute coronary syndrome was observed at six months. CONCLUSIONS: CCTA has higher diagnostic performance than DSE in the evaluation of patients with recent chest pain, normal ECG findings, and negative troponine to exclude coronary artery disease.

Role of emotional competence in residents' simulated emergency care performance: a mixed-methods study.

OBJECTIVE: Emergency situations can generate negative affect in medical personnel, which can negatively impact on the quality of care. Several studies have demonstrated a positive influence of emotional competence (EC) on negative affect. The goal of this study was to test the effect of EC level on simulated emergency care situation in medical residents. METHODS: The sample included 21 medical residents caring for a simulated seriously wounded person whose condition suddenly deteriorated. Medical performance was scored by expert medical doctors (MDs). EC level and affective states were evaluated with self-assessment questionnaires. Finally, the origin of the negative affect experienced by the residents was identified through individual interviews. RESULTS: Higher EC levels were found to be associated with better medical performance and a lower intensity of negative affect. The latter two variables were found to correlate negatively. The main source of negative affect for residents was the inability to establish a diagnosis, regardless of their EC level and their medical performance. CONCLUSIONS: The results suggest that residents who have a high EC level are better able to manage negative affect, so that they are better able to put their medical knowledge to work and explore alternative diagnoses. Emotional-management training for residents who, as new MDs, have limited experience may be beneficial to complement simulation exercises. Additional studies should be considered to better define the links between the affect experienced by MDs and their thought processes during establishment of a diagnosis.

How to estimate aortic characteristic impedance from magnetic resonance and applanation tonometry data?

OBJECTIVES: Compare seven previous methods for the estimation of aortic characteristic impedance, which contributes to left ventricle pulsatile load, from phase-contrast cardiovascular magnetic resonance (CMR) and applanation tonometry data. METHODS: We studied 77 healthy (43 ±â€Š16 years) individuals and 16 hypertensive (61 ±â€Š9 years) patients, who consecutively underwent ascending aorta CMR and carotid tonometry, resulting in flow and pressure waveforms, respectively. Characteristic impedance was semi-automatically estimated in time domain from these latter waveforms, using seven methods. The methods were based on the following: methods 1-4, magnitudes at specific times; method 5, early-systolic up-slope; method 6, time-derivatives peak; and method 7, pressure-flow loop early-systolic slope. RESULTS: Aortic characteristic impedance was significantly increased in hypertensive patients when compared to elderly controls (n = 32) with a similar mean age of (59 ±â€Š8 years) when using methods based on 95% of peak flow, up-slopes, and derivatives peaks (P < 0.05). When considering healthy individuals, impedance indices were significantly correlated to central pulse pressure for all methods (P < 0.005). Finally, characteristic impedance was correlated to the frequency-domain reference values (r > 0.65, P < 0.0001), with a slight superiority for the same three methods as above (r > 0.82, P < 0.0001). CONCLUSIONS: This is the first study demonstrating phase-contrast CMR and tonometry usefulness in aortic characteristic impedance temporal estimation. Methods based on 95% of peak flow, as well as those based on derivative peaks and up-slopes, which are fast and independent of curve preprocessing, were slightly superior. They can be easily integrated in a clinical workflow and may help to understand the complementarity of this pulsatile index with other CMR aortic geometry and stiffness measures in the setting of left ventricle-aortic coupling.

Epstein-Barr virus reactivation in critically ill immunocompetent patients.

BACKGROUND: Herpes viruses can be reactivated among immunocompetent patients in intensive care unit (ICU). Cytomegalovirus (CMV) and herpes simplex virus (HSV) have been the most studied. We hypothesized that Epstein-Barr virus (EBV) could also be reactivated in immunocompetent patients during their stay in ICU and that this would be associated with morbidity and mortality. METHODS: This prospective observational study included 90 patients with an ICU stay of ≥ 5 days. CMV and HSV were considered when clinically suspected and DNA was researched in blood or bronchoalveolar lavage (BAL). EBV DNA viral quantification was performed in the blood samples. RESULTS: EBV DNA was detected in blood of 61 patients (median length for positivity of 7.5 days). CMV DNA was detected in blood of 16 patients (median length for positivity of 13.5 days) and BAL of 6 patients. HSV1 DNA was detected in the BAL of 28 patients (median length for positivity of 7.5 days). Nineteen patients had no viral reactivation, 1 experienced only CMV, 32 had only EBV, 5 had only HSV, 6 had EBV and CMV, 14 had EBV and HSV, and 9 patients reactivated three viruses. Mortality was higher among patients with EBV reactivation (33/61 vs. 7/25, p = 0.02). Length of stay (21 vs. 10 days, p < 0.001) and length of mechanical ventilation (15 vs. 7 days, p < 0.001) were higher among patients with EBV reactivation. CONCLUSIONS: This study shows that EBV DNA is detected in blood of diverse ICU patients with ≥ 5 days of stay and that it is associated with morbidity and mortality. Larger dynamic prospective studies are needed to correlate viral reactivation with immune system evolution during ICU stay and to determine the role of polyviral reactivations.

Geometry is a major determinant of flow reversal in proximal aorta.

The aim of this study is to quantify aortic backward flow (BF) using phase-contrast cardiovascular magnetic resonance (PC-CMR) and to study its associations with age, indexes of arterial stiffness, and geometry. Although PC-CMR blood flow studies showed a simultaneous presence of BF and forward flow (FF) in the ascending aorta (AA), the relationship between aortic flows and aging as well as arterial stiffness and geometry in healthy volunteers has never been reported. We studied 96 healthy subjects [47 women, 39 ± 15 yr old (19-79 yr)]. Aortic stiffness [arch pulse wave velocity (PWVAO), AA distensibility], geometry (AA diameter and arch length), and parameters related to AA BF and FF (volumes, peaks, and onset times) were estimated from CMR. Applanation tonometry carotid-femoral pulse-wave velocity (PWVCF), carotid augmentation index, and time to return of the reflected pressure wave were assessed. Whereas FF parameters remained unchanged, BF onset time shortened significantly (R(2) = 0.18, P < 0.0001) and BF volume and BF-to-FF peaks ratio increased significantly (R(2) = 0.38 and R(2) = 0.44, respectively, P < 0.0001) with aging. These two latter BF indexes were also related to stiffness indexes (PWVCF, R(2) > 0.30; PWVAO, R(2) > 0.24; and distensibility, R(2) > 0.20, P < 0.001), augmentation index (R(2) > 0.20, P < 0.001), and aortic geometry (AA diameter, R(2) > 0.58; and arch length, R(2) > 0.31, P < 0.001). In multivariate analysis, aortic diameter was the strongest independent correlate of BF beyond age effect. In conclusion, AA BF estimated using PC-CMR increased significantly in terms of magnitude and volume and appeared earlier with aging and was mostly determined by aortic geometry. Thus BF indexes could be relevant markers of subclinical arterial wall alterations.

Long-term changes in arterial structure and function and left ventricular geometry after enzyme replacement therapy in patients affected with Fabry disease.

AIMS: Fabry disease is a lysosomal storage disorder due to deficient alpha-galactosidase A activity, characterised by glycosphingolipids deposition in tissues. Patients have a common arterial involvement and contract progressive renal and cardiac disease. Although short-term effects of enzyme replacement therapy (ERT) on target organs have been established, no data are available on the long-term outcome. METHODS AND RESULTS: We studied the effects of ERT (agalsidase beta, 1 mg/kg/14 days) on arterial and cardiac structure and function during a longitudinal study beginning in 1999, with 4.5 ± 0.4 years follow-up (four visits) in 30 patients (age: 33 ± 12 years). In addition, we studied 16 untreated Fabry patients during 2.6 ± 1.6 years (two visits). Aortic stiffness was determined by carotid-femoral pulse wave velocity, central pulse pressure by aplanation tonometry, and carotid and radial intima-media thickness and diameter by high definition echotracking device. Left ventricular mass was determined by MRI. A significant decrease in aortic stiffness (-0.56 ± 0.13 m/s/yr, p = 0.0002) was observed after ERT whereas central pulse pressure did not change. Carotid intima-media thickness (IMT) increased (+18 ± 6 µm/yr; p < 0.005) whereas radial IMT remained stable. Radial artery diameter decreased (-50 ± 20 µm/years, p < 0.05) whereas carotid diameter did not change. Carotid circumferential wall stress was reduced (-1.7 ± 0.6 kPa/yrs, p < 0.01). Left ventricular mass index significantly decreased (-7.8 ± 2.3 g/m(2)/yr, p < 0.005). CONCLUSION: A sustained reduction in aortic stiffness and left ventricular hypertrophy, and a limited radial artery wall thickening were observed after long-term enzyme replacement therapy. There was no significant benefit of treatment on carotid hypertrophy.

Early thoracic aorta enlargement in asymptomatic individuals at risk for cardiovascular disease: determinant factors and clinical implication.

OBJECTIVES: We analyzed, in above-average risk asymptomatic individuals, the factors determining early thoracic aorta enlargement. METHODS: Ascending aortic diameter (AAD) was measured with noncontrast multidetector computed tomography in 345 participants (mean age 56 years; 78% men) without cardiovascular disease. We analyzed the associations of AAD with risk factors and Framingham risk score (FRS), multidetector computed tomography-assessed coronary artery calcium (CAC), and ultrasound interrogation of plaque presence at five sites (right and left carotid arteries, right and left femoral arteries, and abdominal aorta), the number of diseased sites with presence of plaque being counted from 0 to 5. RESULTS: AAD was positively associated with age (P < 0.001), male sex (P < 0.01), body surface area (BSA; P < 0.001), hypertension (P < 0.001), systolic and diastolic blood pressures in individuals without antihypertensive medication (P < 0.05, P < 0.01), and FRS (P < 0.001). AAD was positively associated with CAC score after adjusting for age, sex, and BSA (P < 0001) or for FRS and BSA (P < 0.001). AAD was higher in the presence of three, four, or five than in the presence of no, one, or two diseased sites with plaque, after adjusting for age, sex, and BSA (P < 0.05) or for FRS and BSA (P < 0.001). When participants were divided into subsets by AAD tertiles and by number of sites with plaque, FRS and CAC score were greatest in individuals with AAD top tertile and 3-5 sites with plaque and lowest in those with AAD bottom tertile and 0-2 sites with plaque (P < 0.001). CONCLUSION: These findings suggest that thoracic ascending aorta dilatation is related to hypertension and represents a part of a generalized atherosclerotic process of the entire vasculature.

Automated segmentation of the aorta from phase contrast MR images: validation against expert tracing in healthy volunteers and in patients with a dilated aorta.

PURPOSE: To assess if segmentation of the aorta can be accurately achieved using the modulus image of phase contrast (PC) magnetic resonance (MR) acquisitions. MATERIALS AND METHODS: PC image sequences containing both the ascending and descending aorta of 52 subjects were acquired using three different MR scanners. An automated segmentation technique, based on a 2D+t deformable surface that takes into account the features of PC aortic images, such as flow-related effects, was developed. The study was designed to: 1) assess the variability of our approach and its robustness to the type of MR scanner, and 2) determine its sensitivity to aortic dilation and its accuracy against an expert manual tracing. RESULTS: Interobserver variability in the lumen area was 0.59 +/- 0.92% for the automated approach versus 10.09 +/- 8.29% for manual segmentation. The mean Dice overlap measure was 0.945 +/- 0.014. The method was robust to the aortic size and highly correlated (r = 0.99) with the manual tracing in terms of aortic area and diameter. CONCLUSION: A fast and robust automated segmentation of the aortic lumen was developed and successfully tested on images provided by various MR scanners and acquired on healthy volunteers as well as on patients with a dilated aorta.

A polydioxanone electrospun valved patch to replace the right ventricular outflow tract in a growing lamb model.

A major issue in congenital heart surgery is the lack of viable right ventricular outflow tract (RVOT) replacement materials. Several biomaterials have been used, with different scaffolds and cells, but they have failed to restore a tri-layered RVOT, and reoperations are often required. We investigated the function, histological changes and potential of growth and tissue regeneration of polydioxanone (PDO) electrospun bioabsorbable valved patches seeded with mesenchymal stem cells (MSCs) in the RVOT of growing lambs. Autologous blood-derived MSCs were labeled with quantum dots and seeded on PDO electrospun valved patches. Those were implanted into the RVOT of 6 growing lambs followed up until 8 months. Results were assessed by echocardiography, magnetic resonance imaging (MRI), histology, immunohistochemistry and biochemical assays. Tissue-engineered RVOT were neither stenotic nor aneurismal and displayed a growth potential, with less fibrosis, less calcifications and no thrombus compared with control polytetrafluoroethylene (PTFE)-pericardial patches. The PDO scaffold was completely degraded and replaced by a viable, three-layered, endothelialized tissue and an extracellular matrix with elastic fibers similar to that of native tissue. Detection of quantum dots at 1 month suggested that at least some of the cells were-derived from the grafted cells. A polydioxanone electrospun tissue-engineered valved transannular patch seems to be a promising device in restoring a living RVOT and could ultimately lead to applications in the treatment of congenital RVOT diseases.