Purpose: In digital breast tomosynthesis (DBT), radiologists need to review a stack of 20 to 80 tomosynthesis images, depending upon breast size. This causes a significant increase in reading time. However, it is currently unknown whether there is a perceptual benefit to viewing a mass in the 3D tomosynthesis volume.
View Article and Find Full Text PDFImportance: A clear dosing regimen for methotrexate in psoriasis is lacking, and this might lead to a suboptimal treatment. Because methotrexate is affordable and globally available, a uniform dosing regimen could potentially optimize the treatment of patients with psoriasis worldwide.
Objective: To reach international consensus among psoriasis experts on a uniform dosing regimen for treatment with methotrexate in adult and pediatric patients with psoriasis and identify potential future research topics.
In the critical setting of a trauma team activation, team composition is crucial information that should be accessible at a glance. This calls for a technological solution, which are widely available, that allows access to the whereabouts of personnel. This diversity presents decision makers and users with many choices and considerations.
View Article and Find Full Text PDFPropranolol is an ADRB2 blocker that regulates heart muscle contractions, smooth muscle relaxation, and glycogenolysis. In addition, an increasing number of applications in dermatology have been described, most prominently, the use as a first-line treatment for infantile hemangiomas. We here show that propranolol enhances IL-8-induced neutrophil chemotaxis and reduces the release of ROS after immune complex stimulation.
View Article and Find Full Text PDFNovel iterative image reconstruction methods can help reduce the required radiation dose in x-ray diagnostics such as computed tomography (CT), while maintaining sufficient image quality. Since some of the established image quality measures are not appropriate for reliably judging the quality of images derived by iterative methods, alternative approaches such as task-specific quality assessment would be highly desirable for acceptance or constancy testing. Task-based image quality methods are also closer to tasks performed by the radiologists, such as lesion detection.
View Article and Find Full Text PDFThe channelized-Hotelling observer (CHO) was investigated as a surrogate of human observers in task-based image quality assessment. The CHO with difference-of-Gaussian (DoG) channels has shown potential for the prediction of human detection performance in digital mammography (DM) images. However, the DoG channels employ parameters that describe the shape of each channel.
View Article and Find Full Text PDFPurpose: Vascular remodeling is a significant pathological feature of various pulmonary diseases, which may be assessed by quantitative computed tomography (CT) imaging. The purpose of this study was therefore to develop and validate an automatic method for quantifying pulmonary vascular morphology in CT images.
Methods: The proposed method consists of pulmonary vessel extraction and quantification.
Mammography images undergo vendor-specific processing, which may be nonlinear, before radiologist interpretation. Therefore, to test the entire imaging chain, the effect of image processing should be included in the assessment of image quality, which is not current practice. For this purpose, model observers (MOs), in combination with anthropomorphic breast phantoms, are proposed to evaluate image quality in mammography.
View Article and Find Full Text PDFPurpose: To design a 3D printed anthropomorphic lung vessel phantom for CT image quality assessment and to evaluate the phantom image and dose characteristics.
Methods: An in-house algorithm generated a vessel tree model, based on human lungs anatomy, which was 3D printed using a multi jet modeling printer (0.25 mm ≤ vessel diameters ≤ 8.
Purpose: To study the feasibility of a channelized Hotelling observer (CHO) to predict human observer performance in detecting calcification-like signals in mammography images of an anthropomorphic breast phantom, as part of a quality control (QC) framework.
Methods: A prototype anthropomorphic breast phantom with inserted gold disks of 0.25 mm diameter was imaged with two different digital mammography x-ray systems at four different dose levels.
Purpose: The task-based assessment of image quality using model observers is increasingly used for the assessment of different imaging modalities. However, the performance computation of model observers needs standardization as well as a well-established trust in its implementation methodology and uncertainty estimation. The purpose of this work was to determine the degree of equivalence of the channelized Hotelling observer performance and uncertainty estimation using an intercomparison exercise.
View Article and Find Full Text PDFPurpose: To study the feasibility of a task-based framework composed of an anthropomorphic breast phantom and mathematical model observers (MOs) for the evaluation of system-processed mammographic images.
Methods: A prototype anthropomorphic breast phantom with inserted gold discs of 0.1 mm and 0.
Purpose: Model observers (MOs) are of interest in the field of medical imaging to assess image quality. However, before procedures using MOs can be proposed in quality control guidelines for mammography systems, we need to know whether MOs are sensitive to changes in image quality and correlations in background structure. Therefore, as a proof of principle, in this study human and model observer (MO) performance are compared for the detection of calcification-like objects using different background structures and image quality levels of unprocessed mammography images.
View Article and Find Full Text PDFPurpose: In mammography, images are processed prior to display. Model observers (MO) are candidates to objectively evaluate processed images if they can predict human observer performance for detail detection. The aim of this study was to investigate if the channelized Hotelling observer (CHO) can be configured to predict human observer performance in mammography like images.
View Article and Find Full Text PDFPurpose: In mammography, images are processed prior to display. Current methodologies based on physical image quality measurements are however not designed for the evaluation of processed images. Model observers (MO) might be suitable for this evaluation.
View Article and Find Full Text PDFCurrent digital mammography (DM) X-ray systems are equipped with advanced automatic exposure control (AEC) systems, which determine the exposure factors depending on breast composition. In the supplement of the European guidelines for quality assurance in breast cancer screening and diagnosis, a phantom-based test is included to evaluate the AEC response to local dense areas in terms of signal-to-noise ratio (SNR). This study evaluates the proposed test in terms of SNR and dose for four DM systems.
View Article and Find Full Text PDFThe treatment of brain arteriovenous malformations (AVMs) can be performed as a minimally invasive X-ray-guided procedure using a microcatheter for navigation to reach the target site. The performance of the interventional vascular surgery devices used for AVM was compared in four hospitals. The relation between image quality and the entrance surface air kerma (ESAK) was assessed for the default protocols for digital subtraction angiography (DSA) and fluoroscopy.
View Article and Find Full Text PDFRadiat Prot Dosimetry
June 2016
The purpose of this study was to compare dose and image quality of wireless detectors for digital chest radiography. Entrance dose at both the detector (EDD) and phantom (EPD) and image quality were measured for wireless detectors of seven different vendors. Both the local clinical protocols and a reference protocol were evaluated.
View Article and Find Full Text PDFEvaluation of image quality (IQ) in Computed Tomography (CT) is important to ensure that diagnostic questions are correctly answered, whilst keeping radiation dose to the patient as low as is reasonably possible. The assessment of individual aspects of IQ is already a key component of routine quality control of medical x-ray devices. These values together with standard dose indicators can be used to give rise to 'figures of merit' (FOM) to characterise the dose efficiency of the CT scanners operating in certain modes.
View Article and Find Full Text PDFFor the evaluation of the average glandular dose (AGD) in digital mammography (DM) and digital breast tomosynthesis (DBT) phantoms simulating standard model breasts are used. These phantoms consist of slabs of polymethyl methacrylate (PMMA) or a combination of PMMA and polyethylene (PE). In the last decades the automatic exposure control (AEC) increased in complexity and became more sensitive to (local) differences in breast composition.
View Article and Find Full Text PDFThis paper studies low contrast detectability (LCD) performance of two model observers in CT phantom images acquired at different kVp levels and compares the results with humans in a 2-alternative forced choice experiment (2-AFC). Images of the Catphan phantom with objects of different contrasts (0.5 and 1%) and diameters (2-15 mm) were acquired in an Aquilion ONE 320-detector row CT (Toshiba Medical Systems, Tokyo, Japan), in two experiments, selecting (80-100-120-135 kV) with fixed mAs and varying the mAs to keep the dose constant, respectively.
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