225 research outputs found
Fijación activa y perforación ventricular: ¿una nueva entidad?
First, a new active fixation lead was implanted in the interventricular septum; the old lead was then extracted with a Cook stylet. The
patient’s clinical course was satisfactory and there were no procedure-related complications.
In conclusion, within the battery of diagnostic tests available to investigate suspected cardiac perforation, computed angiotomography
of the chest is a highly useful complementary technique for the management of this complication
LIVE FUEL MOISTURE CONTENT AND IGNITION PROBABILITY IN THE IBERIAN PENINSULAR TERRITORY OF SPAIN
This paper presents an operational algorithm to produce Live Fuel Moisture Content (LFMC) at national scale from MODIS data. The algorithm is based on the inversion of Radiative Transfer Models (RTM) that estimate moisture content based on different simulation scenarios. In
addition, logistic regression models were calibrated to convert the derived LFMC values into
Ignition Probability (IP) maps. The areas under the curve obtained by the Receiver Operating
Characteristic (ROC) plot method provided by the models were close to 0.6. Several statistical
analyses were performed in order to ascertain whether the variables proposed to be included in the fire danger model were significantly related to forest fires. A non parametric U-Mann-Withney test confirmed significant differences between fire and non-fire pixels (p<0.001). Fire pixels occurred at significantly lower LFMC values than the non-fire pixels
Principios básicos de resonancia magnética cardiovascular (RMC): secuencias, planos de adquisición y protocolo de estudio
ABSTRACT
Evaluation of the cardiovascular system with
magnetic resonance (CMR) has become one of the most
relevant and up-to-the-minute clinical applications of
this diagnostic technique, as CMR makes possible an
exact and reproducible study of the anatomy and
function of the heart and great vessels. The complexity
of this technique is mainly due to the anatomical
location and orientation of the cardiovascular
structures, the specific CMR sequences that have to be
used and a lack of familiarity amongst radiologists
regarding cardiovascular pathology. In this report the
most basic principles of CMR are described. The clinical
usefulness of anatomical, functional, and flow
quantification sequences are discussed, conventional
CMR acquisition planes are described, and an easy CMR
study protocol is proposed
Safety, feasibility, and hemodynamic response of regadenoson for stress perfusion CMR
Owing to its pharmacodynamics and posology, the use of regadenoson for stress cardiac magnetic resonance (CMR) has
potential advantages over other vasodilators. We sought to evaluate the safety, hemodynamic response and diagnostic
performance of regadenoson stress-CMR in routine clinical practice. All regadenoson stress-CMR examinations performed
between May 2017 and July 2020 at our institution were retrospectively reviewed. A total of 698 studies were included
for the final analysis. A conventional stress/rest protocol was performed using a 1.5T MRI scanner (Magnetom Aera, Siemens Healthineers, Erlangen, Germany). Adverse events, clinical symptoms, and hemodynamic response were assessed.
Diagnostic accuracy of the test was evaluated in patients who underwent invasive coronary angiography. Nearly half of
patients (48.5%) remained asymptomatic. Most common clinical symptoms included dyspnea (137, 19.6%), chest pain
(116, 16.6%) and flushing (44, 6.3%). Two patients (0.28%) could not complete the examination due to severe hypotension or unbearable chest pain. Overall, an increase in heart rate (HR) response (36.2% [IQR: 22.5–50.9]) and a decrease
in systolic and diastolic blood pressure (BP) (median systolic BP response of -5% [IQR: -11.5-0.6]; median diastolic BP
response of -6.3 mmHg [IQR: -13.4-0]) was observed. Patients with symptoms induced by regadenoson showed higher
HR response (40.3%, IQR: 26.4–56.1 vs. 32.4%, IQR: 19-45.6, p<0.001), whereas a blunted HR response was observed
in diabetic (29.6%, IQR: 18.4–42 p<0.001), obese (31.7%, IQR: 20.7–46.2 p=0.005) and patients aged 70 years or
older (32.9%, IQR: 22.6–43.1 p<0.001). Overall, regadenoson stress-CMR showed 95.65% (IQ 91.49–99.81) sensitivity,
54.84% (IQ 35.71–73.97) specificity, 86.99% (IQ 82.74–94.68) positive predictive value, and 77.27% (IQ 57.49–97.06)
negative predictive value for detecting significant coronary stenosis as compared with invasive coronary angiography.
Regadenoson is a well-tolerated vasodilator that can be safely employed for stress perfusion CMR, with high diagnostic
performanc
Úlcera penetrante de aorta ascendente en un paciente asintomático
La úlcera penetrante de aorta (UPA) es la ulceración de una placa aterosclerótica que afecta a la lámina
elástica interna de la aorta, y que puede evolucionar hacia un hematoma de pared o una disección aórtica si se
produce el paso de sangre hacia la capa media. A pesar
de que se localiza más frecuentemente en la aorta descendente, puede presentar una alta mortalidad en caso
de situarse en la aorta ascendente, donde la cirugÃa está
indicada aunque el paciente se encuentre asintomático.
Presentamos el caso de un paciente sin sintomatologÃa
con úlcera penetrante de aorta ascendente (UPAA) ascendente sometido a sustitución de aorta ascendente
por una prótesis vascular.Penetrating aortic ulcer (PAU) has been defined
as an atherosclerotic plaque ulceration that breaks
the internal elastic lamina of the aorta, which may
progress to a wall hematoma or aortic dissection in
case of blood seeping into the middle layer. Although
PAU is commonly located in the descending aorta,
the involvement of the ascending aorta can be fatal.
Therefore, surgery is indicated even in asymptomatic
patients presenting an ascending PAU. We report on an
asymptomatic patient with ascending PAU referred for
replacement of the ascending aorta with a composite
prosthetic graft
Multiparametric renal magnetic resonance imaging: A reproducibility study in renal allografts with stable function
Monitoring renal allograft function after transplantation is key for the early detection of allograft impairment, which in turn can contribute to preventing the loss of the allograft. Multiparametric renal MRI (mpMRI) is a promising noninvasive technique to assess and characterize renal physiopathology; however, few studies have employed mpMRI in renal allografts with stable function (maintained function over a long time period). The purposes of the current study were to evaluate the reproducibility of mpMRI in transplant patients and to characterize normal values of the measured parameters, and to estimate the labeling efficiency of Pseudo-Continuous Arterial Spin Labeling (PCASL) in the infrarenal aorta using numerical simulations considering experimental measurements of aortic blood flow profiles. The subjects were 20 transplant patients with stable kidney function, maintained over 1 year. The MRI protocol consisted of PCASL, intravoxel incoherent motion, and T1 inversion recovery. Phase contrast was used to measure aortic blood flow. Renal blood flow (RBF), diffusion coefficient (D), pseudo-diffusion coefficient (D*), flowing fraction (
f
), and T1 maps were calculated and mean values were measured in the cortex and medulla. The labeling efficiency of PCASL was estimated from simulation of Bloch equations. Reproducibility was assessed with the within-subject coefficient of variation, intraclass correlation coefficient, and Bland-Altman analysis. Correlations were evaluated using the Pearson correlation coefficient. The significance level was p less than 0.05. Cortical reproducibility was very good for T1, D, and RBF, moderate for
f
, and low for D*, while medullary reproducibility was good for T1 and D. Significant correlations in the cortex between RBF and
f
(r = 0.66), RBF and eGFR (r = 0.64), and D* and eGFR (r = -0.57) were found. Normal values of the measured parameters employing the mpMRI protocol in kidney transplant patients with stable function were characterized and the results showed good reproducibility of the techniques
Emphysema presence, severity, and distribution has little impact on the clinical presentation of a cohort of patients with mild to moderate COPD
Phenotypic characterization of patients with COPD may have potential
prognostic and therapeutic implications. Available information on the
relationship between emphysema and the clinical presentation in patients with
COPD is limited to advanced stages of the disease. The objective of this study
was to describe emphysema presence, severity, and distribution and its impact on
clinical presentation of patients with mild to moderate COPD. METHODS: One
hundred fifteen patients with COPD underwent clinical and chest CT scan
evaluation for the presence, severity, and distribution of emphysema. Patients
with and without emphysema and with different forms of emphysema distribution
(upper/lower/core/peel) were compared. The impact of emphysema severity and
distribution on clinical presentation was determined. RESULTS: Fifty percent of
the patients had mild homogeneously distributed emphysema (1.84; 0.76%-4.77%).
Upper and core zones had the more severe degree of emphysema. Patients with
emphysema were older, more frequently men, and had lower FEV(1)%, higher total
lung capacity percentage, and lower diffusing capacity of the lung for carbon
monoxide. No differences were found between the clinical or physiologic
parameters of the different emphysema distributions. CONCLUSIONS: In patients
with mild to moderate COPD, although the presence of emphysema has an impact on
physiologic presentation, its severity and distribution seem to have little
impact on clinical presentation
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