Synthetic domain walls in [TbFeGa/TbFe]2 multilayers.

Here we report the possibility of creating synthetic domain walls in nominal [Fe72Ga28/Tb33Fe67]2 multilayers. The magnetization as a function of the temperature reveals the absence of Compensation temperature in the samples which can be understood considering an interdiffusion process that results in the formation of TbFeGa alloys at the nominal FeGa layers. Therefore, samples actually comprise TbFeGa and TbFe layers. The hysteresis loops exhibit magnetization steps related to the nucleation of domain walls formed because of the competition between different interactions: (i) the antiferromagnetic exchange coupling between the heavy rare earth (Tb) and the transition magnetic metal (Fe) inside each layer, (ii) the antiferromagnetic coupling between Tb and Fe at the interfaces, and (iii) the Zeeman energy. In good agreement with the experimental values, the nucleation field of the domain walls has been theoretically calculated taking into account the tilt of the magnetization with respect to the sample plane. Our experimental results indicate that by a proper thickness adjustment, it can be tuned, both the value of the nucleation field and the layer in which this firstly occurs. Experimental values for the exchange bias field have also been calculated.

Parental report of quality of life in children with epilepsy: A Spanish/French comparison.

BACKGROUND: Epilepsy is a chronic neurological condition that affects the quality of life (QoL) of patients and their families. In this study, we compare two sets of reports on QoL that were completed by two samples of parents whose children have epilepsy. METHOD: Parents of children with various types of epilepsy from Spain (N = 196) and France (N = 219) completed the same QoL questionnaire. Medical variables were recorded from the referred specialist doctor for each patient. RESULTS: The factors associated with parental reports on QoL were similar in both countries. Parents of children with nonidiopathic generalized or unclassified epilepsy reported poorer QoL and the highest proportion of learning and behavioral problems. However, the intensity of difficulties varied between the two samples. CONCLUSIONS: This questionnaire made it possible to detect comorbidities and daily life difficulties in children with epilepsy and their families. The type of epilepsy had the same influence on Spanish and French families' ratings of QoL. Families shared the same comorbidities in terms of hyperactivity/attention/sociability problems. Nevertheless, the intensity of reported difficulties varied in both countries, possibly because of differences in cultural and educational environments. This aspect should be further explored in future research.

Accuracy and Time-Efficiency of an Automated Software Tool to Assess Left Ventricular Parameters in Cardiac Magnetic Resonance Imaging.

PURPOSE: Routine manual tracing of cardiac contours is time-consuming and subject to variability. A fully automated software tool may improve reading efficiency. This study was performed to assess the accuracy, reliability, and time-efficiency of a fully automated left ventricular (LV) segmentation software tool to calculate LV volumes and function compared with conventional manual contouring. MATERIALS AND METHODS: Sixty-seven consecutive patients (53 male, mean age 62.5±10.9 y) underwent adenosine stress/rest perfusion cardiac magnetic resonance examination to rule out myocardial ischemia. Double-oblique short-axis 6-mm slice thickness steady-state free precession cine images were acquired to assess LV ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volume (SV) using manual contour tracing and a recently developed fully automated software tool. The length of time needed to obtain LV volumes with each segmentation method was also compared. RESULTS: Compared with manual contouring, the fully automated software tool minimally underestimated LV-EF (mean difference of 2.9%±3.9%) and SV (mean difference of 4.4±8.5 mL) and slightly overestimated ESV (mean difference of -6.4±10.8 mL) and LV mass (mean difference of -14±20.4 g). EDV quantification did not statistically differ. Reliability for EF (concordance correlation coefficient [CCC]=0.92, 95% confidence interval [CI], 0.88-0.95), EDV (CCC=0.98, 95% CI, 0.97-0.99), ESV (CCC=0.96, 95% CI, 0.94-0.97), SV (CCC=0.93, 95% CI, 0.89-0.95), and LV mass (CCC=0.84, 95% CI, 0.76-0.89) was very good. The evaluated software allowed to quantify LV parameters with a 79% reduction in the time required for manual contouring (414.7±91 s vs. 85±16.1 s, respectively, P<0.001). CONCLUSION: Quantification of LV volumes using the evaluated fully automated segmentation software is accurate and time-efficient.

Whole-body computed tomography: a new point of view in a hospital check-up unit? Our experience in 6516 patients.

BACKGROUND: There is a growing awareness that prevention and early diagnosis may reduce the high mortality associated with cancer, cardiovascular and other diseases. The role of whole-body computed tomography (WB-CT) in self-referred and asymptomatic patients has been debated. AIM: To determine frequency and spectrum of WB-CT findings in average-risk subjects derived from a Medical-Check-Up-Unit, to evaluate recommendations reported and distribution according to sex and age-groups. MATERIALS AND METHODS: We retrospectively reviewed 6516 subjects who underwent WB-CT (June 2004/February 2015). All were > 40 years and referred by Medical-Check-Up-Unit of our hospital. The main findings were categorized and classified as normal or not. Its distribution according to sex and age-groups was evaluated using Chi-square test and linear-by-linear association test, respectively. Number of recommendations, type and interval of follow-up were recorded. Descriptive statistics were used. RESULTS: WB-CT performed in 6516 patients (69% men, 31% women, mean age = 58.4 years) revealed chest (81.4%), abdominal (93.06%) and spine (65.39%) abnormalities. Only 1.60% had completely normal exploration. Abnormal WB-CT in men was significantly higher than women (98.64% vs. 97.87%; p = 0.021), with significant increase as age was higher (40-49 years: 95.65%; 50-59 years: 98.33%; 60-69 years: 99.47%; > 69 years: 99.89%) (p < 0.001). Although most findings were benign, we detected 1.47% primary tumors (96, mainly 35 kidneys and 15 lungs). 17.39% of patients received at least one recommendation predominantly in chest (78.19%) and follow-up imaging (69.89%). CONCLUSION: The most common WB-CT findings in asymptomatic subjects are benign. However, this examination allows identifying an important number of relevant and precocious findings that significantly increase with age, involving changes in lifestyle and precocious treatment.

Adenosine triphosphate (ATP) and adenosine cause similar vasodilator effect in patients undergoing stress perfusion cardiac magnetic resonance imaging.

To evaluate the vasodilator effect of adenosine triphosphate (ATP) compared with adenosine in stress perfusion cardiac magnetic resonance (CMR) examinations. A total of thirty-three patients underwent clinically indicated stress/rest perfusion CMR examination following intravenous injection of a total dose of 0.2 mmol/kg of gadobutrol. Individuals were randomly assigned to ATP (160 mcg/kg/min) or adenosine (140 mcg/kg/min). The vasodilator effect of both drugs was analyzed by comparing differences in heart rate, symptoms during stress, and semiquantitative myocardial and splenic perfusion parameters, including time, time to peak, upslope, myocardial perfusion reserve index, tissue perfusion values, splenic and myocardial signal intensity ratios, and splenic-to-myocardial signal intensity ratios. No significant difference was found in heart rate variation between the stressors (26.1 ± 19.1 bpm for ATP vs. 21.7 ± 17.3 bpm for adenosine, p = 0.52). Patients receiving ATP referred less pronounced clinical symptoms. Semiquantitative myocardial perfusion parameters were comparable, and patients in the adenosine and ATP groups showed similar myocardial perfusion reserve index values (2.34 [1.62-2.73] vs 1.63 [1.29-2.10], p = 0.07). Splenic switch off was visually confirmed in all patients and estimated spleen to myocardium ratio was similar (0.92 [0.53-1.09] vs 0.81 [0.53-0.86] with ATP and adenosine, respectively, p = 0.12). Both ATP and adenosine are potent coronary vasodilators that can be safely employed in stress-CMR. Both stressor cause similar hyperemic response. Splenic switch-off can be used to assess stress adequacy in patients undergoing stress-CMR with either adenosine or ATP.

Effect of contrast dose in the quantification of myocardial extra-cellular volume in adenosine stress/rest perfusion cardiac magnetic resonance examinations.

Background Diffuse myocardial fibrosis can be quantified by calculating extra-cellular volume (ECV) from native and post-contrast T1 values using dedicated single bolus contrast medium injection protocols. Purpose To evaluate differences in T1 maps and myocardial ECV measurements in routine stress/rest perfusion cardiovascular magnetic resonance (CMR) examinations after injection of single and double dose of contrast medium. Material and Methods Thirty-seven consecutive patients (30 men; mean age, 62 ± 13 years) underwent clinically indicated adenosine stress/rest perfusion CMR examination to rule out myocardial ischemia following a conventional split-dose contrast medium injection strategy. Native and post-contrast T1 mapping was performed 15 min after the first (0.1 mmol/kg) and second (0.1 mmol/kg) dose of contrast medium using a breath-held Modified Look-Locker Inversion recovery (MOLLI) sequence. Student's t-test for paired samples, Bland-Altman plots, and concordance-correlation coefficients (CCC) for agreement between T1 and ECV calculations after single and double dose of contrast medium were calculated. Intra- and inter-observer agreement for measurements was also analyzed. Results Myocardial T1 values after single and double dose of contrast medium significantly differed (mean difference of 114.1 ± 19.9 ms, P < 0.01). A single dose of contrast agent provided slightly higher ECV values (mean difference of 2.3 ± 1.1%). CCC for ECV calculations was 0.66. Intra- and inter-observer agreement for all measurements was excellent (CCC ≥ 0.83). Conclusion Quantification of myocardial ECV on conventional stress/rest perfusion CMR examination is feasible. T1 maps obtained 15 min after 0.1 mmol/kg of contrast medium provide slightly higher myocardial T1 measurements and ECV values compared with T1 maps obtained after a total dose of 0.2 mmol/kg.