The Experts below are selected from a list of 68109 Experts worldwide ranked by ideXlab platform

Magdalena Bazalovacarter - One of the best experts on this subject based on the ideXlab platform.

  • multi contrast k edge imaging on a bench top photon counting ct system acquisition parameter study
    arXiv: Medical Physics, 2020
    Co-Authors: Devon Richtsmeier, Chelsea A S Dunning, K Iniewski, Magdalena Bazalovacarter
    Abstract:

    Purpose: Photon-counting computed tomography (PCCT) shows promise for medical imaging in regards to material separation and imaging of multiple contrast agents. However, many PCCT setups are under development and are not optimized for specific contrast agents or use cases. Here, we demonstrate how experimental system parameters may be varied in order to enhance performance and we propose a set of recommendations to achieve this based on contrast agent. Approach: A table-top PCCT system with a cadmium zinc telluride (CZT) detector capable of separating six energy bins was used to image multiple contrast agents in a small phantom. The contrast agents were separated and the concentration was quantified using K-edge subtraction. To increase system performance, we investigated three parameters: beam Filter Type and thickness, projection acquisition time, and energy bin width. The results from the parameters were compared based on PCCT signal and contrast to noise ratio (CNR) or noise in K-edge images. The concentrations of the contrast agents were quantified in K-edge images and compared to known concentrations. Results: The bench-top PCCT system was able to successfully quantify the contrast agents through K-edge subtraction. Decreasing projection acquisition time showed a decrease in K-edge CNR. However, it did not scale as the square root of time. Filter Type and bin width demonstrated a dependence on the specific contrast agent. Conclusions: The presented bench-top system demonstrated the ability to separate contrast agents using K-edge subtraction and accurately determine contrast concentration in K-edge images. Specific parameters for future use will be chosen based on contrast agent.

Satoru Iwasaki - One of the best experts on this subject based on the ideXlab platform.

  • magnetic resonance plaque imaging to predict the occurrence of the slow flow phenomenon in carotid artery stenting procedures
    Neuroradiology, 2010
    Co-Authors: Masahiko Sakamoto, Toshiaki Taoka, Hiroyuki Nakagawa, Katsutoshi Takayama, Takeshi Wada, Kaoru Myouchin, Toshiaki Akashi, Toshiteru Miyasaka, Akio Fukusumi, Satoru Iwasaki
    Abstract:

    The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a Filter-Type protection device. Thirty-one carotid artery stenotic lesions in 30 patients (28 men and two women; mean age, 71.8 years) were evaluated by MR plaque imaging with black blood T1- and T2-weighted and time-of-flight sequences before CAS. Main plaque components were classified as vulnerable (intraplaque hemorrhage and lipid-rich/necrotic core) or stable (fibrous tissue and dense calcification) from the signal pattern. The plaque classification was statistically compared with the occurrence of slow-flow phenomenon. The slow-flow phenomenon was observed in ten CAS procedures (five flow arrests and five flow reductions). Flow arrests consisted of four vulnerable and one stable plaque, and flow reductions consisted of four vulnerable and one stable plaque. The slow-flow phenomenon occurred significantly (P < 0.01) more frequently in patients with vulnerable plaque. Vulnerable carotid plaques have a significantly higher risk of slow-flow phenomenon than stable plaques. The occurrence of the slow-flow phenomenon can be predicted by MR plaque imaging before CAS.

  • Magnetic resonance plaque imaging to predict the occurrence of the slow-flow phenomenon in carotid artery stenting procedures
    Neuroradiology, 2009
    Co-Authors: Masahiko Sakamoto, Toshiaki Taoka, Hiroyuki Nakagawa, Katsutoshi Takayama, Takeshi Wada, Kaoru Myouchin, Toshiaki Akashi, Toshiteru Miyasaka, Akio Fukusumi, Satoru Iwasaki
    Abstract:

    Introduction The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a Filter-Type protection device.

Devon Richtsmeier - One of the best experts on this subject based on the ideXlab platform.

  • multi contrast k edge imaging on a bench top photon counting ct system acquisition parameter study
    arXiv: Medical Physics, 2020
    Co-Authors: Devon Richtsmeier, Chelsea A S Dunning, K Iniewski, Magdalena Bazalovacarter
    Abstract:

    Purpose: Photon-counting computed tomography (PCCT) shows promise for medical imaging in regards to material separation and imaging of multiple contrast agents. However, many PCCT setups are under development and are not optimized for specific contrast agents or use cases. Here, we demonstrate how experimental system parameters may be varied in order to enhance performance and we propose a set of recommendations to achieve this based on contrast agent. Approach: A table-top PCCT system with a cadmium zinc telluride (CZT) detector capable of separating six energy bins was used to image multiple contrast agents in a small phantom. The contrast agents were separated and the concentration was quantified using K-edge subtraction. To increase system performance, we investigated three parameters: beam Filter Type and thickness, projection acquisition time, and energy bin width. The results from the parameters were compared based on PCCT signal and contrast to noise ratio (CNR) or noise in K-edge images. The concentrations of the contrast agents were quantified in K-edge images and compared to known concentrations. Results: The bench-top PCCT system was able to successfully quantify the contrast agents through K-edge subtraction. Decreasing projection acquisition time showed a decrease in K-edge CNR. However, it did not scale as the square root of time. Filter Type and bin width demonstrated a dependence on the specific contrast agent. Conclusions: The presented bench-top system demonstrated the ability to separate contrast agents using K-edge subtraction and accurately determine contrast concentration in K-edge images. Specific parameters for future use will be chosen based on contrast agent.

Jay S. Yadav - One of the best experts on this subject based on the ideXlab platform.

  • Slow-Flow Phenomenon During Carotid Artery Intervention With Embolic Protection Devices: Predictors and Clinical Outcome
    Journal of the American College of Cardiology, 2005
    Co-Authors: Ivan P. Casserly, Alex Abou-chebl, Robert B. Fathi, David S. Lee, Jacqueline Saw, Jose E. Exaire, Samir R. Kapadia, Christopher Bajzer, Jay S. Yadav
    Abstract:

    Objectives The purpose of this research was to define the predictors of the “slow-reflow” phenomenon during carotid artery intervention with Filter-Type embolic protection devices (EPDs) and to determine its prognostic significance. Background During carotid artery intervention using Filter-Type EPDs, we have observed cases in which there is angiographic evidence of a significant reduction in antegrade flow in the internal carotid artery proximal to the Filter device, termed “slow-flow.” The predictors of this phenomenon and its prognostic significance are unknown. Methods Using a single-center prospective carotid intervention registry, patients with slow-flow were compared to patients with normal flow during carotid intervention with respect to clinical, procedural, and lesion characteristics, and the 30-day incidence of death and stroke. Results A total of 414 patients underwent 453 carotid artery interventions using EPDs. Slow-flow occurred in 42 patients (10.1%) undergoing 42 carotid interventions (9.3%), and most commonly occurred after post-stent balloon dilatation (71.4%). Multivariate logistic regression analysis identified the following predictors of slow-flow: recent history ( Conclusions Slow-flow during carotid intervention with EPDs is a frequent event that is associated with an excess risk of periprocedural stroke. The association of the phenomenon with clinically symptomatic carotid lesions and use of larger stent diameters suggests that embolization of vulnerable plaque elements may play a pathogenic role.

Masahiko Sakamoto - One of the best experts on this subject based on the ideXlab platform.

  • magnetic resonance plaque imaging to predict the occurrence of the slow flow phenomenon in carotid artery stenting procedures
    Neuroradiology, 2010
    Co-Authors: Masahiko Sakamoto, Toshiaki Taoka, Hiroyuki Nakagawa, Katsutoshi Takayama, Takeshi Wada, Kaoru Myouchin, Toshiaki Akashi, Toshiteru Miyasaka, Akio Fukusumi, Satoru Iwasaki
    Abstract:

    The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a Filter-Type protection device. Thirty-one carotid artery stenotic lesions in 30 patients (28 men and two women; mean age, 71.8 years) were evaluated by MR plaque imaging with black blood T1- and T2-weighted and time-of-flight sequences before CAS. Main plaque components were classified as vulnerable (intraplaque hemorrhage and lipid-rich/necrotic core) or stable (fibrous tissue and dense calcification) from the signal pattern. The plaque classification was statistically compared with the occurrence of slow-flow phenomenon. The slow-flow phenomenon was observed in ten CAS procedures (five flow arrests and five flow reductions). Flow arrests consisted of four vulnerable and one stable plaque, and flow reductions consisted of four vulnerable and one stable plaque. The slow-flow phenomenon occurred significantly (P < 0.01) more frequently in patients with vulnerable plaque. Vulnerable carotid plaques have a significantly higher risk of slow-flow phenomenon than stable plaques. The occurrence of the slow-flow phenomenon can be predicted by MR plaque imaging before CAS.

  • Magnetic resonance plaque imaging to predict the occurrence of the slow-flow phenomenon in carotid artery stenting procedures
    Neuroradiology, 2009
    Co-Authors: Masahiko Sakamoto, Toshiaki Taoka, Hiroyuki Nakagawa, Katsutoshi Takayama, Takeshi Wada, Kaoru Myouchin, Toshiaki Akashi, Toshiteru Miyasaka, Akio Fukusumi, Satoru Iwasaki
    Abstract:

    Introduction The purpose is to investigate the feasibility of magnetic resonance (MR) plaque imaging in predicting the arterial flow impairment (slow-flow phenomenon) during carotid artery stenting (CAS) using a Filter-Type protection device.