AI-based, automated chamber volumetry from gated, non-contrast CT.

BACKGROUND: Accurate chamber volumetry from gated, non-contrast cardiac CT (NCCT) scans can be useful for potential screening of heart failure. OBJECTIVES: To validate a new, fully automated, AI-based method for cardiac volume and myocardial mass quantification from NCCT scans compared to contrasted CT Angiography (CCTA). METHODS: Of a retrospectively collected cohort of 1051 consecutive patients, 420 patients had both NCCT and CCTA scans at mid-diastolic phase, excluding patients with cardiac devices. Ground truth values were obtained from the CCTA scans. RESULTS: The NCCT volume computation shows good agreement with ground truth values. Volume differences [95% CI ] and correlation coefficients were: -9.6 [-45; 26] mL, r â€‹= â€‹0.98 for LV Total, -5.4 [-24; 13] mL, r â€‹= â€‹0.95 for LA, -8.7 [-45; 28] mL, r â€‹= â€‹0.94 for RV, -5.2 [-27; 17] mL, r â€‹= â€‹0.92 for RA, -3.2 [-42; 36] mL, r â€‹= â€‹0.91 for LV blood pool, and -6.7 [-39; 26] g, r â€‹= â€‹0.94 for LV wall mass, respectively. Mean relative volume errors of less than 7% were obtained for all chambers. CONCLUSIONS: Fully automated assessment of chamber volumes from NCCT scans is feasible and correlates well with volumes obtained from contrast study.

Dynamic Imaging of Aortic Pathologies: Review of Clinical Applications and Imaging Protocols.

The past decade has seen significant advances in dynamic imaging of the aorta. Today's vascular surgeons have the opportunity to choose from a wide array of imaging modalities to evaluate different aortic pathologies. While vascular ultrasound and aortography are considered to be the bread and butter imaging modalities, newer dynamic imaging techniques provide time-resolved information in various aortic pathologies. However, despite growing evidence of their advantages in the literature, they have not been routinely adopted. In order to understand the role of these emerging modalities, one must understand their principles, advantages, and limitations in the context of various clinical scenarios. In this review, we provide an overview of dynamic imaging techniques for aortic pathologies and describe various dynamic computed tomography and magnetic resonance imaging protocols, clinical applications, and potential future directions.

Association Between FFRCT and Instantaneous Wave-Free Ratio (iFR) of Intermediate Lesions on Coronary Computed Tomography Angiography.

BACKGROUND: New data suggests long term outcomes of coronary revascularization based on instantaneous wave free ratio (iFR) are equivalent to invasive fractional flow reserve (FFR). We aimed to evaluate the correlation between non-invasive FFR derived from cardiac CT (FFRCT) and iFR. METHODS: Data from 21 patients with 26 vessels, who underwent both FFRCT computation and invasive iFR measurement, were analysed. We evaluated diagnostic performance of FFRCT according to two cut-off values of ≤0.80 and ≤0.70 with iFR ≤0.89 as the reference standard. RESULTS: In a per vessel analysis, the average diameter stenosis was 59%, mean FFRCT was 0.81 while mean iFR was 0.90. Using an FFRCT cut-off of 0.80, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy for FFRCT were 86%, 84%, 67%, 94%, and 85% respectively. When the cut-off was lowered to 0.70, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy for FFRCT were 57%, 100%, 100%, 86% and 88% respectively. CONCLUSION: FFRCT correlates well with iFR in this small retrospective study. Larger studies are required to confirm this finding.

Effects of nitrate and sulfate on the performance and bacterial community structure of membrane-less single-chamber air-cathode microbial fuel cells.

Membrane-less, single-chamber, air-cathode, microbial fuel cells (ML-SC MFCs) have attracted attention as being suitable for wastewater treatment. In this study, the effects of nitrate and sulfate on the performance of ML-SC MFCs and their bacterial structures were evaluated. The maximum power density increased after nitrate addition from 8.6 mW·m-2 to 14.0 mW·m-2, while it decreased after sulfate addition from 11.5 mW·m-2 to 7.7 mW·m-2. The chemical oxygen demand removal efficiencies remained at more than 90% regardless of the nitrate or sulfate additions. The nitrate was removed completely (93.0%) in the ML-SC MFC, while the sulfate removal efficiency was relatively low (17.6%). Clostridium (23.1%), Petrimonas (20.0%), and unclassified Rhodocyclaceae (6.2%) were dominant on the anode before the addition of nitrate or sulfate. After the addition of nitrate, Clostridium was still the most dominant on the anode (23.6%), but Petrimonas significantly decreased (6.0%) and unclassified Rhodocyclaceae increased (17.1%). After the addition of sulfate, the amount of Clostridium almost doubled in the composition on the anode (43.2%), while Petrimonas decreased (5.5%). The bacterial community on the cathode was similar to that on the anode after the addition of nitrate. However, Desulfovibrio was remarkably dominant on the cathode (32.9%) after the addition of sulfate. These results promote a deeper understanding of the effects of nitrate or sulfate on the ML-SC MFCs' performance and their bacterial community.

Nuclear cardiology: 2014 innovations and developments.

Nuclear cardiac imaging is acknowledged as a robust technique for clinically assessing patients with a wide spectrum of cardiac illnesses. Recent technical, radiotracer, and stressor advancements continue to expand the role of nuclear cardiology for the accurate diagnosis and prognostication of patients with known or suspected coronary artery disease. The introduction of I-123 MIBG represents another advance for assessing risk in patients with congestive heart failure and depressed left ventricular (LV) function. Software and hardware innovations and recent shifts in acquisition protocols have greatly improved image quality, reduced cost and radiation exposure, and continue to promote patient and physician satisfaction. The following article will highlight recent achievements in the field that continue to foster a patient-centered imaging approach.

Gender differences revealed in the right posterior temporal areas during Navon letter identification tasks.

Gender differences in temporo-spectral EEG patterns during verbal cognitive performance are poorly understood. The aim of the present study was to examine whether the event-related dynamics of EEG differ between genders during the performance of Navon letter identification tasks (NLITs). To this end, the EEG patterns of 40 subjects were recorded during the NLIT performance. We compared behavioral outcomes, event-related temporo-spectral dynamics, and source distribution of neural oscillations within cortical regions of male and female subjects. We found that male subjects exhibited greater induced neural activities than female subjects in right temporo-parietal areas at theta and alpha frequency bands. Source imaging for the time ranges at which maximal gender differences were observed revealed gender-dependent estimated current densities in the right posterior temporal regions. These gender differences can be explained by the existence of distinct, gender-specific hemispheric specialization. Thus, gender differences should be considered during behavioral tasks and electrophysiological measurements.

A case report of thoracic aneurysm with aortopulmonary artery fistula.

Rupture of an aortic aneurysm into the pulmonary artery is a rare and often a fatal event. This complication results in the development of an acute left to right shunt, volume overload, and rapid right heart deterioration. We describe a case of thoracic aortic aneurysm in whom the diagnosis of a communication with the pulmonary artery was made on the basis of transthoracic echocardiography.

Percent change in B-type natriuretic peptide levels during treadmill exercise as a screening test for exercise-induced myocardial ischemia.

BACKGROUND: Myocardial ischemia leads to changes in regional wall stress. Induction of ischemia during a treadmill exercise, although brief, may lead to transient elevation in the plasma level of B-type natriuretic peptide (BNP) from baseline levels, which could serve as a biochemical marker of myocardial ischemia. METHODS: Sixty subjects (mean age 57, 41 men) undergoing myocardial single-photon emission computed tomography (SPECT) in conjunction with Bruce protocol treadmill exercise for evaluation of chest pain or screening for ischemia had their BNPs measured (Triage Biosite Test) at baseline, immediately postexercise, and 10 to 15 minutes after exercise. RESULTS: Of the 60 patients, 10 had ischemic perfusion defects by SPECT (mean 14%, range 5%-37%). In patients with no evidence of ischemia, median BNP level at baseline was 15.05 pg/mL (interquartile range 7-37.7), increased significantly immediately postexercise median level (34.7 pg/mL [14.9-67.6]), and decreased toward baseline levels within 10 to 15 minutes postexercise (20.3 pg/mL [8.6-48.5], analysis of variance P < .001). This transient rise in BNP level during exercise was also observed in patients with ischemia but was more pronounced. Percent change in BNP level from baseline for each minute of exercise was significantly higher in patients with evidence of ischemia compared with those without (14% +/- SEM 2.3 vs 7% +/- SEM 1.2, P = .014). Patients with and without ischemia did not differ in age, exercise time, peak systolic or diastolic blood pressure, peak heart rate, or other baseline characteristics. A > 10% change in BNP level from rest per minute of exercise had a sensitivity of 80%, a specificity of 71%, and a negative predictive value of 92% to detect reversible ischemia by SPECT. CONCLUSION: Transient elevation in BNP occurs during treadmill exercise and is more pronounced in patients with ischemia. B-type natriuretic peptides may therefore be used in combination with treadmill exercise for the evaluation of coronary artery disease.