Optimize scan timing in abdominal multiphase CT: Bolus Tracking with an Individualized Post-trigger Delay

2021 ◽  
pp. 110139
Author(s):  
Juan Yu ◽  
Shushen Lin ◽  
Hao Lu ◽  
Rui Wang ◽  
Jie Liu ◽  
...  
Keyword(s):  
Trigger Delay ◽  
Bolus Tracking ◽  
Multiphase Ct

scholarly journals Detecting the pulmonary trunk in CT scout views using deep learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aydin Demircioğlu ◽  
Magdalena Charis Stein ◽  
Moon-Sung Kim ◽  
Henrike Geske ◽  
Anton S. Quinsten ◽  
...  
Keyword(s):  
Deep Learning ◽  
Validation Cohort ◽  
High Accuracy ◽  
Pulmonary Trunk ◽  
Reference Standard ◽  
Bolus Tracking ◽  
Wilcoxon Rank Sum Test ◽  
Scout View ◽  
Axial Ct ◽  
Anterior Posterior

AbstractFor CT pulmonary angiograms, a scout view obtained in anterior–posterior projection is usually used for planning. For bolus tracking the radiographer manually locates a position in the CT scout view where the pulmonary trunk will be visible in an axial CT pre-scan. We automate the task of localizing the pulmonary trunk in CT scout views by deep learning methods. In 620 eligible CT scout views of 563 patients between March 2003 and February 2020 the region of the pulmonary trunk as well as an optimal slice (“reference standard”) for bolus tracking, in which the pulmonary trunk was clearly visible, was annotated and used to train a U-Net predicting the region of the pulmonary trunk in the CT scout view. The networks’ performance was subsequently evaluated on 239 CT scout views from 213 patients and was compared with the annotations of three radiographers. The network was able to localize the region of the pulmonary trunk with high accuracy, yielding an accuracy of 97.5% of localizing a slice in the region of the pulmonary trunk on the validation cohort. On average, the selected position had a distance of 5.3 mm from the reference standard. Compared to radiographers, using a non-inferiority test (one-sided, paired Wilcoxon rank-sum test) the network performed as well as each radiographer (P < 0.001 in all cases). Automated localization of the region of the pulmonary trunk in CT scout views is possible with high accuracy and is non-inferior to three radiographers.

scholarly journals A Comparative Evaluation of Pressure-Triggering and Flow-Triggering in Pressure Support Ventilation (PSV) for Neonates Using an Animal Model

1995 ◽  
Vol 23 (3) ◽  
pp. 302-306 ◽  
Author(s):  
A. Uchiyama ◽  
H. Imanaka ◽  
N. Taenaka ◽  
S. Nakano ◽  
Y. Fujino ◽  
...  
Keyword(s):  
Animal Model ◽  
Pressure Support Ventilation ◽  
Airway Pressure ◽  
Comparative Evaluation ◽  
Pressure Support ◽  
Trigger Delay ◽  
Support Ventilation ◽  
Respiratory Flow ◽  
Oesophageal Pressure ◽  
Support Time

The triggering system in pressure support ventilation needs to respond rapidly, especially in neonates. The aim of this study was to compare the effects of flow-triggered and pressure-triggered pressure support ventilation on neonatal mechanical ventilation using an animal model. Respiratory flow, airway pressure, oesophageal pressure, and diaphragmatic electromyogram were measured during pressure support ventilation in five anaesthetized rabbits. The animals were connected to a VIPBIRD (Bird, U.S.A.) (CPAP mode, pressure support ventilation, 5 cm H2O) and PEEP 0 cm H2O). Flow-triggering sensitivity was set at 0.21/min, 0.51/min, 1.011/min, or 1.51/min. Pressure-triggering sensitivity was set at −1.0 cm H2O. Shorter trigger delay and longer pressure support time were observed in flow-triggering. There was also less diaphragmatic activity in flow-triggering as evidenced by the amplitude of integrated diaphragmatic electromyogram and negative deflection of oesophageal pressure. The findings suggest that flow-triggering will prove superior to pressure-triggering in pressure support ventilation for neonates.

Predicting the stages of liver fibrosis with multiphase CT radiomics based on volumetric features

2021 ◽  
Author(s):  
Enming Cui ◽  
Wansheng Long ◽  
Juanhua Wu ◽  
Qing Li ◽  
Changyi Ma ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Volumetric Features ◽  
Multiphase Ct

scholarly journals Validating a Local Arterial Input Function Method for Improved Perfusion Quantification in Stroke

2011 ◽  
Vol 31 (11) ◽  
pp. 2189-2198 ◽  
Author(s):  
Lisa Willats ◽  
Soren Christensen ◽  
Henry K Ma ◽  
Geoffrey A Donnan ◽  
Alan Connelly ◽  
...  
Keyword(s):  
Time Course ◽  
Arterial Input Function ◽  
Input Function ◽  
Perfusion Magnetic Resonance Imaging ◽  
Data Sets ◽  
Bolus Tracking ◽  
Perfusion Quantification ◽  
Magnetic Resonance Imaging Mri ◽  
Arterial Input Functions ◽  
Contrast Bolus

In bolus-tracking perfusion magnetic resonance imaging (MRI), temporal dispersion of the contrast bolus due to stenosis or collateral supply presents a significant problem for accurate perfusion quantification in stroke. One means to reduce the associated perfusion errors is to deconvolve the bolus concentration time-course data with local Arterial Input Functions (AIFs) measured close to the capillary bed and downstream of the arterial abnormalities causing dispersion. Because the MRI voxel resolution precludes direct local AIF measurements, they must be extrapolated from the surrounding data. To date, there have been no published studies directly validating these local AIFs. We assess the effectiveness of local AIFs in reducing dispersion-induced perfusion error by measuring the residual dispersion remaining in the local AIF deconvolved perfusion maps. Two approaches to locating the local AIF voxels are assessed and compared with a global AIF deconvolution across 19 bolus-tracking data sets from patients with stroke. The local AIF methods reduced dispersion in the majority of data sets, suggesting more accurate perfusion quantification. Importantly, the validation inherently identifies potential areas for perfusion underestimation. This is valuable information for the identification of at-risk tissue and management of stroke patients.

scholarly journals Optimal Timing of Contrast Enhancement in Coronary CT Angiography Using the Bolus-tracking Method

2007 ◽  
Vol 63 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Takaaki Kitai ◽  
Takesi Ogawa ◽  
Jun Noguti ◽  
Muneyosi Hara ◽  
Hitosi Otuka ◽  
...  
Keyword(s):  
Contrast Enhancement ◽  
Ct Angiography ◽  
Coronary Ct Angiography ◽  
Optimal Timing ◽  
Tracking Method ◽  
Bolus Tracking ◽  
Coronary Ct

scholarly journals Streamlining trigger delay estimation for T1 mapping

2016 ◽  
Vol 18 (S1) ◽  
Author(s):  
George L Mathew ◽  
Vassilis Vassiliou ◽  
Ee Ling Heng ◽  
Gillian C Smith ◽  
Sri Anita ◽  
...  
Keyword(s):  
T1 Mapping ◽  
Delay Estimation ◽  
Trigger Delay

A new principle of UHVDC line pilot protection based on trigger angle control characteristics

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Lu Wang ◽  
Zhenxing Li ◽  
Tan Hong ◽  
Hanli Weng ◽  
Zhenhua Li
Keyword(s):  
Control System ◽  
Trigger Delay ◽  
Internal Fault ◽  
Internal Parameters ◽  
Simulation Based ◽  
Transition Resistance ◽  
Change Tendency ◽  
Pilot Protection

AbstractA new principle of UHVDC Line pilot protection based on internal parameters of the trigger angle of converter is proposed, in order to improve the ability of the protection to withstand transition resistance. Through the analysis of UHVDC control system, it is found that, due to the regulation of control system, in terms of trigger delay angle of rectifier side and trigger leading angle of inverter side, the change tendency in internal fault and external fault is different. Thus, the protection criterion is constructed. Compared with the traditional protection principle using voltage and current to establish protection criteria, this principle uses internal parameters as protection quantity. The simulation based on PSCAD/EMTDC verifies the effectiveness of the protection principle.

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