ResearchPad - Radiological and Ultrasound Technology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[A comprehensive characterization of myocardial and vascular phenotype in pediatric chronic kidney disease using cardiovascular magnetic resonance imaging]]> https://www.researchpad.co/product?articleinfo=5b4cea91463d7e11b2f0759a

Background

Children with chronic kidney disease (CKD) have increased cardiovascular mortality. Identifying high-risk children who may benefit from further therapeutic intervention is difficult as cardiovascular abnormalities are subtle. Although transthoracic echocardiography may be used to detect sub-clinical abnormalities, it has well-known problems with reproducibility that limit its ability to accurately detect these changes. Cardiovascular magnetic resonance (CMR) is the reference standard method for assessing blood flow, cardiac structure and function. Furthermore, recent innovations enable the assessment of radial and longitudinal myocardial velocity, such that detection of sub-clinical changes is now possible. Thus, CMR may be ideal for cardiovascular assessment in pediatric CKD. This study aims to comprehensively assess cardiovascular function in pediatric CKD using CMR and determine its relationship with CKD severity.

Methods

A total of 120 children (40 mild, 40 moderate, 20 severe pre-dialysis CKD subjects and 20 healthy controls) underwent CMR with non-invasive blood pressure (BP) measurements. Cardiovascular parameters measured included systemic vascular resistance (SVR), total arterial compliance (TAC), left ventricular (LV) structure, ejection fraction (EF), cardiac timings, radial and longitudinal systolic and diastolic myocardial velocities. Between group comparisons and regression modelling were used to identify abnormalities in CKD and determine the effects of renal severity on myocardial function.

Results

The elevation in mean BP in CKD was accompanied by significantly increased afterload (SVR), without evidence of arterial stiffness (TAC) or increased fluid overload. Left ventricular volumes and global function were not abnormal in CKD. However, there was evidence of LV remodelling, prolongation of isovolumic relaxation time and reduced systolic and diastolic myocardial velocities.

Conclusion

Abnormal cardiovascular function is evident in pre-dialysis pediatric CKD. Novel CMR biomarkers may be useful for the detection of subtle abnormalities in this population. Further studies are needed to determine to prognostic value of these biomarkers.

Electronic supplementary material

The online version of this article (10.1186/s12968-018-0444-0) contains supplementary material, which is available to authorized users.

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<![CDATA[Differential flow improvements after valve replacements in bicuspid aortic valve disease: a cardiovascular magnetic resonance assessment]]> https://www.researchpad.co/product?articleinfo=5b4ad276463d7e6c275999f1

Background

Abnormal aortic flow patterns in bicuspid aortic valve disease (BAV) may be partly responsible for the associated aortic dilation. Aortic valve replacement (AVR) may normalize flow patterns and potentially slow the concomitant aortic dilation. We therefore sought to examine differences in flow patterns post AVR.

Methods

Ninety participants underwent 4D flow cardiovascular magnetic resonance: 30 BAV patients with prior AVR (11 mechanical, 10 bioprosthetic, 9 Ross procedure), 30 BAV patients with a native aortic valve and 30 healthy subjects.

Results

The majority of subjects with mechanical AVR or Ross showed normal flow pattern (73% and 67% respectively) with near normal rotational flow values (7.2 ± 3.9 and 10.6 ± 10.5 mm2/ms respectively vs 3.8 ± 3.1 mm2/s for healthy subjects; both p > 0.05); and reduced in-plane wall shear stress (0.19 ± 0.13 N/m2 for mechanical AVR vs. 0.40 ± 0.28 N/m2 for native BAV, p < 0.05). In contrast, all subjects with a bioprosthetic AVR had abnormal flow patterns (mainly marked right-handed helical flow), with comparable rotational flow values to native BAV (20.7 ± 8.8 mm2/ms and 26.6 ± 16.6 mm2/ms respectively, p > 0.05), and a similar pattern for wall shear stress. Data before and after AVR (n = 16) supported these findings: mechanical AVR showed a significant reduction in rotational flow (30.4 ± 16.3 → 7.3 ± 4.1 mm2/ms; p < 0.05) and in-plane wall shear stress (0.47 ± 0.20 → 0.20 ± 0.13 N/m2; p < 0.05), whereas these parameters remained similar in the bioprosthetic AVR group.

Conclusions

Abnormal flow patterns in BAV disease tend to normalize after mechanical AVR or Ross procedure, in contrast to the remnant abnormal flow pattern after bioprosthetic AVR. This may in part explain different aortic growth rates post AVR in BAV observed in the literature, but requires confirmation in a prospective study.

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<![CDATA[Diagnostic performance of 18F-FDG PET/CT using point spread function reconstruction on initial staging of rectal cancer: a comparison study with conventional PET/CT and pelvic MRI]]> https://www.researchpad.co/product?articleinfo=5b4a9036463d7e67a7d90ac7

Background

Accurate staging is crucial for treatment selection and prognosis prediction in patients with rectal cancer. Point spread function (PSF) reconstruction can improve spatial resolution and signal-to-noise ratio of PET imaging. The aim of this study was to evaluate the effectiveness of 18F-FDG PET/CT with PSF reconstruction for initial staging in rectal cancer compared with conventional PET/CT and pelvic MRI.

Methods

A total of 59 patients with rectal cancer underwent preoperative 18F-FDG PET/CT and pelvic MRI. The maximum standardized uptake value (SUVmax) and lesion to background (L/B) ratio of possible metastatic lymph nodes, and metabolic tumor volumes (MTVs) of primary tumors were calculated. For N and T (T1-2 vs T3-4) staging, sensitivities, specificities, positive predictive values, negative predictive values, and accuracies were compared between conventional PET/CT [reconstructed with ordered subset expectation maximization (OSEM)], PSF-PET/CT (reconstructed with OSEM+PSF), and pelvic MRI. Histopathologic analysis was the reference standard.

Results

For N staging, PSF-PET/CT provided higher sensitivity (78.6%) than conventional PET/CT (64.3%), and pelvic MRI (57.1%), and all techniques showed high specificity (PSF-PET: 95.4%, conventional PET: 96.7%, pelvic MRI: 93.5%). SUVmax and L/B ratio were significantly higher in PSF-PET/CT than conventional-PET/CT (p < 0.001). The accuracy for T staging in PSF-PET/CT (69.4%) was not significantly different to conventional PET/CT (73.5%) and pelvic MRI (73.5%). MTVs of PSF and conventional PET showed a significant difference among T stages (p < 0.001), with higher values in advanced stages. In M staging, both PSF and conventional PET/CT diagnosed all distant metastases correctly.

Conclusions

PSF-PET/CT produced images with higher lesion-to-background contrast than conventional PET/CT, which allowed improved detection of lymph node metastasis without compromising specificity, and showed comparable diagnostic value to MRI in local staging. PSF-PET/CT is likely to have a great value for initial staging in rectal cancer.

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<![CDATA[A generalized framework unifying image registration and respiratory motion models and incorporating image reconstruction, for partial image data or full images]]> https://www.researchpad.co/product?articleinfo=5bf49232d5eed0c484763c74

Abstract

Surrogate-driven respiratory motion models relate the motion of the internal anatomy to easily acquired respiratory surrogate signals, such as the motion of the skin surface. They are usually built by first using image registration to determine the motion from a number of dynamic images, and then fitting a correspondence model relating the motion to the surrogate signals. In this paper we present a generalized framework that unifies the image registration and correspondence model fitting into a single optimization. This allows the use of ‘partial’ imaging data, such as individual slices, projections, or k-space data, where it would not be possible to determine the motion from an individual frame of data. Motion compensated image reconstruction can also be incorporated using an iterative approach, so that both the motion and a motion-free image can be estimated from the partial image data. The framework has been applied to real 4DCT, Cine CT, multi-slice CT, and multi-slice MR data, as well as simulated datasets from a computer phantom. This includes the use of a super-resolution reconstruction method for the multi-slice MR data. Good results were obtained for all datasets, including quantitative results for the 4DCT and phantom datasets where the ground truth motion was known or could be estimated.

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<![CDATA[The 2014 liver ultrasound tracking benchmark]]> https://www.researchpad.co/product?articleinfo=5be71acfd5eed0c4842ac2ad <![CDATA[Iterative framework for the joint segmentation and CT synthesis of MR images: application to MRI-only radiotherapy treatment planning]]> https://www.researchpad.co/product?articleinfo=5be71ac0d5eed0c4842abf63 <![CDATA[Intra-arterial and intravenous applications of Iosimenol 340 injection, a new non-ionic, dimeric, iso-osmolar radiographic contrast medium: phase 2 experience]]> https://www.researchpad.co/product?articleinfo=5bbeeecc40307c387b7373fa

Background

Iosimenol 340 injection is a new, dimeric, iso-osmolar, iodinated contrast medium for X-ray angiography.

Purpose

To compare the safety and efficacy of iosimenol injection to iodixanol injection in two randomized, controlled phase 2 trials.

Material and Methods

One hundred and forty-four adult patients were enrolled in the two trials, one for evaluation during arteriography and the other for evaluation during computed tomography. Safety was compared by assessing adverse events, vital signs, ECGs, and laboratory parameters. Efficacy was assessed as X-ray attenuation in the computed tomography (CT) trial and as the quality of contrast enhancement in the arteriography trial.

Results

There were no statistically significant differences in terms of safety or efficacy between the two contrast media. Both were well tolerated upon intravenous as well as intra-arterial injection. The most common adverse event was a feeling of warmth (observed in 35.1% of the patients with Iosimenol injection and 44.3% with iodixanol injection).

Conclusion

Iosimenol upon intravenous as well as upon intra-arterial injection exhibits a safety profile and shows an efficacy similar to that of iodixanol.

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<![CDATA[The Image-Guided Surgery Toolkit IGSTK: An Open Source C++ Software Toolkit]]> https://www.researchpad.co/product?articleinfo=5b7d0ab1463d7e30b734ccce

This paper presents an overview of the image-guided surgery toolkit (IGSTK). IGSTK is an open source C++ software library that provides the basic components needed to develop image-guided surgery applications. It is intended for fast prototyping and development of image-guided surgery applications. The toolkit was developed through a collaboration between academic and industry partners. Because IGSTK was designed for safety-critical applications, the development team has adopted lightweight software processes that emphasizes safety and robustness while, at the same time, supporting geographically separated developers. A software process that is philosophically similar to agile software methods was adopted emphasizing iterative, incremental, and test-driven development principles. The guiding principle in the architecture design of IGSTK is patient safety. The IGSTK team implemented a component-based architecture and used state machine software design methodologies to improve the reliability and safety of the components. Every IGSTK component has a well-defined set of features that are governed by state machines. The state machine ensures that the component is always in a valid state and that all state transitions are valid and meaningful. Realizing that the continued success and viability of an open source toolkit depends on a strong user community, the IGSTK team is following several key strategies to build an active user community. These include maintaining a users and developers’ mailing list, providing documentation (application programming interface reference document and book), presenting demonstration applications, and delivering tutorial sessions at relevant scientific conferences.

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<![CDATA[Protégé: A Tool for Managing and Using Terminology in Radiology Applications]]> https://www.researchpad.co/product?articleinfo=5b7d0ab5463d7e30b734ccd1

The development of standard terminologies such as RadLex is becoming important in radiology applications, such as structured reporting, teaching file authoring, report indexing, and text mining. The development and maintenance of these terminologies are challenging, however, because there are few specialized tools to help developers to browse, visualize, and edit large taxonomies. Protégé (http://protege.stanford.edu) is an open-source tool that allows developers to create and to manage terminologies and ontologies. It is more than a terminology-editing tool, as it also provides a platform for developers to use the terminologies in end-user applications. There are more than 70,000 registered users of Protégé who are using the system to manage terminologies and ontologies in many different domains. The RadLex project has recently adopted Protégé for managing its radiology terminology. Protégé provides several features particularly useful to managing radiology terminologies: an intuitive graphical user interface for navigating large taxonomies, visualization components for viewing complex term relationships, and a programming interface so developers can create terminology-driven radiology applications. In addition, Protégé has an extensible plug-in architecture, and its large user community has contributed a rich library of components and extensions that provide much additional useful functionalities. In this report, we describe Protégé’s features and its particular advantages in the radiology domain in the creation, maintenance, and use of radiology terminology.

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<![CDATA[Design and Implementation of an Open Source Indexing Solution for a Large Set of Radiological Reports and Images]]> https://www.researchpad.co/product?articleinfo=5b7d0ab2463d7e30b734cccf

This paper hopes to share the insights we experienced during designing, building, and running an indexing solution for a large set of radiological reports and images in a production environment for more than 3 years. Several technical challenges were encountered and solved in the course of this project. One hundred four million words in 1.8 million radiological reports from 1989 to the present were indexed and became instantaneously searchable in a user-friendly fashion; the median query duration is only 31 ms. Currently, our highly tuned index holds 332,088 unique words in four languages. The indexing system is feature-rich and language-independent and allows for making complex queries. For research and training purposes it certainly is a valuable and convenient addition to our radiology informatics toolbox. Extended use of open-source technology dramatically reduced both implementation time and cost. All software we developed related to the indexing project has been made available to the open-source community covered by an unrestricted Berkeley Software Distribution-style license.

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<![CDATA[Rapid Development of Medical Imaging Tools with Open-Source Libraries]]> https://www.researchpad.co/product?articleinfo=5b7d0aab463d7e30b734ccc9

Rapid prototyping is an important element in researching new imaging analysis techniques and developing custom medical applications. In the last ten years, the open source community and the number of open source libraries and freely available frameworks for biomedical research have grown significantly. What they offer are now considered standards in medical image analysis, computer-aided diagnosis, and medical visualization. A cursory review of the peer-reviewed literature in imaging informatics (indeed, in almost any information technology-dependent scientific discipline) indicates the current reliance on open source libraries to accelerate development and validation of processes and techniques. In this survey paper, we review and compare a few of the most successful open source libraries and frameworks for medical application development. Our dual intentions are to provide evidence that these approaches already constitute a vital and essential part of medical image analysis, diagnosis, and visualization and to motivate the reader to use open source libraries and software for rapid prototyping of medical applications and tools.

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<![CDATA[Open Source Software Projects of the caBIG™ In Vivo Imaging Workspace Software Special Interest Group]]> https://www.researchpad.co/product?articleinfo=5b7d0ab0463d7e30b734cccd

The Cancer Bioinformatics Grid (caBIG™) program was created by the National Cancer Institute to facilitate sharing of IT infrastructure, data, and applications among the National Cancer Institute-sponsored cancer research centers. The program was launched in February 2004 and now links more than 50 cancer centers. In April 2005, the In Vivo Imaging Workspace was added to promote the use of imaging in cancer clinical trials. At the inaugural meeting, four special interest groups (SIGs) were established. The Software SIG was charged with identifying projects that focus on open-source software for image visualization and analysis. To date, two projects have been defined by the Software SIG. The eXtensible Imaging Platform project has produced a rapid application development environment that researchers may use to create targeted workflows customized for specific research projects. The Algorithm Validation Tools project will provide a set of tools and data structures that will be used to capture measurement information and associated needed to allow a gold standard to be defined for the given database against which change analysis algorithms can be tested. Through these and future efforts, the caBIG™ In Vivo Imaging Workspace Software SIG endeavors to advance imaging informatics and provide new open-source software tools to advance cancer research.

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<![CDATA[Proactively Monitoring Departmental Clinical IT Systems with an Open Source Availability System]]> https://www.researchpad.co/product?articleinfo=5b7d0aad463d7e30b734cccb

The goal of all radiology information technology (IT) support organizations is excellent customer service through the availability of critical clinical information services, such as picture archiving communication systems and radiology information systems. Despite these goals, IT support personnel often act like firefighters, reacting to each problem, but unable to prevent or predict other problems. Proactive support is always more desirable than reactive support. Warning signs may exist well before a technical issue becomes system wide or the user is affected. The objective for IT support organizations in health care should be to maximize system uptime by using proactive monitoring systems for failures and to automatically detect failures through systems management tools. We report on the implementation of Nagios, an open source monitoring tool, as an availability management system in a diagnostic imaging department and on customized applications and protocols specific to radiology needs.

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<![CDATA[The Open-Source Neuroimaging Research Enterprise]]> https://www.researchpad.co/product?articleinfo=5b7d0aa7463d7e30b734ccc6

While brain imaging in the clinical setting is largely a practice of looking at images, research neuroimaging is a quantitative and integrative enterprise. Images are run through complex batteries of processing and analysis routines to generate numeric measures of brain characteristics. Other measures potentially related to brain function – demographics, genetics, behavioral tests, neuropsychological tests – are key components of most research studies. The canonical scanner – PACS – viewing station axis used in clinical practice is therefore inadequate for supporting neuroimaging research. Here, we model the neuroimaging research enterprise as a workflow. The principal components of the workflow include data acquisition, data archiving, data processing and analysis, and data utilization. We also describe a set of open-source applications to support each step of the workflow and the transitions between these steps. These applications include DIGITAL IMAGING AND COMMUNICATIONS IN MEDICINE viewing and storage tools, the EXTENSIBLE NEUROIMAGING ARCHIVE TOOLKIT data archiving and exploration platform, and an engine for running processing/analysis pipelines. The overall picture presented is aimed to motivate open-source developers to identify key integration and communication points for interoperating with complimentary applications.

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<![CDATA[Benefits of Using the DCM4CHE DICOM Archive]]> https://www.researchpad.co/product?articleinfo=5b7d0aa5463d7e30b734ccc4 ]]> <![CDATA[Mastering DICOM with DVTk]]> https://www.researchpad.co/product?articleinfo=5b7d0ab6463d7e30b734ccd2

The Digital Imaging and Communications in Medicine (DICOM) Validation Toolkit (DVTk) is an open-source framework with potential value for anyone working with the DICOM standard. DICOM’s flexibility requires hands-on experience in understanding ways in which the standard’s interpretation may vary among vendors. DVTk was developed as a clinical engineering tool to aid and accelerate DICOM integration at clinical sites. DVTk is used to provide an independent measurement of the accuracy of a product’s DICOM interface, according to both the DICOM standard and the product’s conformance statement. DVTk has stand-alone tools and a framework with which developers can create new tools. We provide an overview of the architecture of the toolkit, sample scenarios of its utility, and evidence of its relative ease of use. Our goal is to encourage involvement in this open-source project and attract developers to build off and further enrich this platform for DICOM integration testing.

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<![CDATA[Partial Volume Compensated Reconstruction of Three-dimensional Mass Shapes in Mammographic Images]]> https://www.researchpad.co/product?articleinfo=5b7cba8a463d7e2027cafbb0

Accurately reconstructing the three-dimensional mass shapes in mammographic images is important for classifying the abnormality into malignant or benign. In this paper, a partial volume compensated reconstruction technique for mass shapes is presented. The two-dimensional shapes of the masses are first automatically segmented using a region growing approach. The 3D mass shapes are then iteratively refined according to an algebraic reconstruction technique. Partial volume estimation is applied on the boundary to get a smoother 3D shape. Evaluation results show that the proposed algorithm improves the accuracy of the mass reconstruction.

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<![CDATA[GridIMAGE: A Novel Use of Grid Computing to Support Interactive Human and Computer-Assisted Detection Decision Support]]> https://www.researchpad.co/product?articleinfo=5b7c8b66463d7e1d0d7dcaa3

This paper describes a Grid-aware image reviewing system (GridIMAGE) that allows practitioners to (a) select images from multiple geographically distributed digital imaging and communication in medicine (DICOM) servers, (b) send those images to a specified group of human readers and computer-assisted detection (CAD) algorithms, and (c) obtain and compare interpretations from human readers and CAD algorithms. The currently implemented system was developed using the National Cancer Institute caGrid infrastructure and is designed to support the identification of lung nodules on thoracic computed tomography. However, the infrastructure is general and can support any type of distributed review. caGrid data and analytical services are used to link DICOM image databases and CAD systems and to interact with human readers. Moreover, the service-oriented and distributed structure of the GridIMAGE framework enables a flexible system, which can be deployed in an institution (linking multiple DICOM servers and CAD algorithms) and in a Grid environment (linking the resources of collaborating research groups). GridIMAGE provides a framework that allows practitioners to obtain interpretations from one or more human readers or CAD algorithms. It also provides a mechanism to allow cooperative imaging groups to systematically perform image interpretation tasks associated with research protocols.

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<![CDATA[A Filmless Radiology Department in a Full Digital Regional Hospital: Quantitative Evaluation of the Increased Quality and Efficiency]]> https://www.researchpad.co/product?articleinfo=5b7c8b69463d7e1d0d7dcaa5

Reggio Emilia hospital installed Picture Archiving and Communications Systems (PACS) as the final step towards a completely digital clinical environment completing the HIS/EMR and 1,400 web/terminals for patient information access. Financial benefits throughout the hospital were assessed upfront and measured periodically. Key indicators (radiology exam turnaround time, number of radiology procedures performed, inpatients length of stay before and after the PACS implementation, etc.) were analyzed and values were statistically tested to assess workflow and productivity improvements. The hospital went “filmless” in 28 weeks. Between the half of 2004 and the respective period in 2003, overall Radiology Department productivity increased by 12%, TAT improved by more than 60%. Timelier patient care resulted in decreased lengths of stay. Neurology alone experienced a 12% improvement in average patient stay. To quantify the impact of PACS on the average hospital stays and the expected productivity benefits to inpatient productivity were used a “high level” and a “detailed” business model. Annual financial upsides have exceeded $1.9 millions/year. A well-planned PACS deployment simplifies imaging workflow and improves patient care throughout the hospital while delivering substantial financial benefits. Staff buy-in was the key in this process and on-going training and process monitoring are a must.

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<![CDATA[Medical Imaging Informatics: How It Improves Radiology Practice Today]]> https://www.researchpad.co/product?articleinfo=5b7c8b68463d7e1d0d7dcaa4 ]]>