Reference-based linear curve fitting for bolus arrival time estimation in 4D MRA and MR perfusion-weighted image sequences

2010 ◽  
Vol 65 (1) ◽  
pp. 289-294 ◽  
Author(s):  
Nils Daniel Forkert ◽  
Jens Fiehler ◽  
Thorsten Ries ◽  
Till Illies ◽  
Dietmar Möller ◽  
...  
Keyword(s):  
Curve Fitting ◽  
Arrival Time ◽  
Time Estimation ◽  
Image Sequences ◽  
Mr Perfusion ◽  
Weighted Image ◽  
Bolus Arrival Time

scholarly journals Enhancement-constrained acceleration: A robust reconstruction framework in breast DCE-MRI

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258621
Author(s):  
Ty O. Easley ◽  
Zhen Ren ◽  
Byol Kim ◽  
Gregory S. Karczmar ◽  
Rina F. Barber ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Arrival Time ◽  
Arterial Input Function ◽  
Time Estimation ◽  
Significant Loss ◽  
Small Time ◽  
Initial Slope ◽  
Real Patient ◽  
Dce Mri ◽  
Bolus Arrival Time

In patients with dense breasts or at high risk of breast cancer, dynamic contrast enhanced MRI (DCE-MRI) is a highly sensitive diagnostic tool. However, its specificity is highly variable and sometimes low; quantitative measurements of contrast uptake parameters may improve specificity and mitigate this issue. To improve diagnostic accuracy, data need to be captured at high spatial and temporal resolution. While many methods exist to accelerate MRI temporal resolution, not all are optimized to capture breast DCE-MRI dynamics. We propose a novel, flexible, and powerful framework for the reconstruction of highly-undersampled DCE-MRI data: enhancement-constrained acceleration (ECA). Enhancement-constrained acceleration uses an assumption of smooth enhancement at small time-scale to estimate points of smooth enhancement curves in small time intervals at each voxel. This method is tested in silico with physiologically realistic virtual phantoms, simulating state-of-the-art ultrafast acquisitions at 3.5s temporal resolution reconstructed at 0.25s temporal resolution (demo code available here). Virtual phantoms were developed from real patient data and parametrized in continuous time with arterial input function (AIF) models and lesion enhancement functions. Enhancement-constrained acceleration was compared to standard ultrafast reconstruction in estimating the bolus arrival time and initial slope of enhancement from reconstructed images. We found that the ECA method reconstructed images at 0.25s temporal resolution with no significant loss in image fidelity, a 4x reduction in the error of bolus arrival time estimation in lesions (p < 0.01) and 11x error reduction in blood vessels (p < 0.01). Our results suggest that ECA is a powerful and versatile tool for breast DCE-MRI.

Accurate bolus arrival time estimation using piecewise linear model fitting

2017 ◽  
Author(s):  
Elhassan Abdou ◽  
Johan de Mey ◽  
Mark De Ridder ◽  
Jef Vandemeulebroucke
Keyword(s):  
Linear Model ◽  
Arrival Time ◽  
Piecewise Linear ◽  
Model Fitting ◽  
Time Estimation ◽  
Piecewise Linear Model ◽  
Bolus Arrival Time

scholarly journals Short-Term Scheduling Model of Cluster Tool in Wafer Fabrication

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1029
Author(s):  
Ying-Mei Tu
Keyword(s):  
Arrival Time ◽  
Time Estimation ◽  
Advanced Technology ◽  
Shop Floor ◽  
Process Time ◽  
Short Term ◽  
Work In Process ◽  
Scheduling Model ◽  
Cluster Tools ◽  
Cluster Tool

Since last decade, the cluster tool has been mainstream in modern semiconductor manufacturing factories. In general, the cluster tool occupies 60% to 70% of production machines for advanced technology factories. The most characteristic feature of this kind of equipment is to integrate the relevant processes into one single machine to reduce wafer transportation time and prevent wafer contaminations as well. Nevertheless, cluster tools also increase the difficulty of production planning significantly, particularly for shop floor control due to complicated machine configurations. The main objective of this study is to propose a short-term scheduling model. The noteworthy goal of scheduling is to maximize the throughput within time constraints. There are two modules included in this scheduling model—arrival time estimation and short-term scheduling. The concept of the dynamic cycle time of the product’s step is applied to estimate the arrival time of the work in process (WIP) in front of machine. Furthermore, in order to avoid violating the time constraint of the WIP, an algorithm to calculate the latest time of the WIP to process on the machine is developed. Based on the latest process time of the WIP and the combination efficiency table, the production schedule of the cluster tools can be re-arranged to fulfill the production goal. The scheduling process will be renewed every three hours to make sure of the effectiveness and good performance of the schedule.

scholarly journals Cerebral Arterial Bolus Arrival Time is Prolonged in Multiple Sclerosis and Associated with Disability

2013 ◽  
Vol 34 (1) ◽  
pp. 34-42 ◽  
Author(s):  
David Paling ◽  
Esben Thade Petersen ◽  
Daniel J Tozer ◽  
Daniel R Altmann ◽  
Claudia AM Wheeler-Kingshott ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Gray Matter ◽  
Arrival Time ◽  
Arterial Hemodynamics ◽  
Normal Appearing White Matter ◽  
Imaging Sequence ◽  
Disability Status ◽  
Relapsing Remitting ◽  
Bolus Arrival Time ◽  
Deep Gray Matter

Alterations in the overall cerebral hemodynamics have been reported in multiple sclerosis (MS); however, their cause and significance is unknown. While potential venous causes have been examined, arterial causes have not. In this study, a multiple delay time arterial spin labeling magnetic resonance imaging sequence at 3T was used to quantify the arterial hemodynamic parameter bolus arrival time (BAT) and cerebral blood flow (CBF) in normal-appearing white matter (NAWM) and deep gray matter in 33 controls and 35 patients with relapsing–remitting MS. Bolus arrival time was prolonged in MS in NAWM (1.0±0.2 versus 0.9±0.2 seconds, P=0.031) and deep gray matter (0.90±0.18 versus 0.80±0.14 seconds, P=0.001) and CBF was increased in NAWM (14±4 versus 10±2 mL/100 g/min, P=0.001). Prolonged BAT in NAWM ( P=0.042) and deep gray matter ( P=0.01) were associated with higher expanded disability status score. This study demonstrates alteration in cerebral arterial hemodynamics in MS. One possible cause may be widespread inflammation. Bolus arrival time was longer in patients with greater disability independent of atrophy and T2 lesion load, suggesting alterations in cerebral arterial hemodynamics may be a marker of clinically relevant pathology.

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