Filip Verhelle

A method for myelin fiber orientation mapping using diffusion-weighted MR images

In the past, the anisotropic diffusion of water molecules in white matter in the brain has been correlated to the basic symmetry of the myelin fibers: water diffuses more readily along the fiber direction than perpendicular to it. As a consequence, diffusion sensitized magnetic resonance imaging can be expected to be useful for studying the fiber orientation. In this work, we present a method for exploiting this type of information to map the fiber orientations in the image plane. It makes use of three diffusion-weighted images with sensitizing gradients along x, y and u, an axis at 45 degrees with respect to x and y. The orientation information contained in these images is summarized in a single image representing the angle between the fiber direction and a fixed axis, making use of a cyclic color scale. The method is evaluated using computer simulations for a variety of diffusion weighting strengths and signal-to-noise ratios, tested on a phantom and illustrated on an in vivo example. An extension to the determination of the fiber orientation in three dimensions is also described.

Assessment of the long head of the biceps tendon of the shoulder with 3T magnetic resonance arthrography and CT arthrography

We studied the assessment of proximal biceps tendon lesions including degeneration, tendon luxation, and partial and complete tendon tears with 3T MR arthrography and CT arthrography. Thirty-six patients who underwent both studies, as well as arthroscopy were included in the study. The images were randomized and blinded and independently reviewed by two musculoskeletal radiologists. The pooled sensitivity for lesion detection for CT arthrography was 31% and the specificity 95%. The pooled sensitivity for MR arthrography was 27% and the specificity 94%. There were no statistically significant differences between CT and MR. The interobserver agreement calculated with the kappa statistic was poor for CT and for MR. Both CT arthrography and MR arthrography perform poorly in the detection of biceps tendon pathology of the shoulder.

HIPIN — a generic HIS/RIS-PACS interface based on clinical radiodiagnostic procedures

Within the EurIPACS HIPIN topic a generic HIS/RIS-PACS interface will be designed, implemented and evaluated. It is generally agreed that integration with the HIS/RIS is essential for the acceptance of PACS in a clinical environment. An interface between HIS/RIS and PACS allows more efficient usage of both systems, better integration of data, better consistency checking on shared data and better security and error handling. Also the PACS performance is improved by using HIS/RIS information to steer the image migration within the PACS. In this paper the functional specifications of the interface are described. These specifications are based on descriptions of clinical radiodiagnostic procedures. The generic interface consists of a common part, and of site specific adapters. The common part is identical for all incarnations and performs message scheduling, processing and logging. The adapters are specific for each communication standard, e.g. ACR-NEMA or HL7, and for each hospital. The interface will be implemented at the radiology department of the Philipps University Hospital in Marburg (Germany) and at the orthopaedic and neuroradiology departments of the hospital of the Free University in Brussels (Belgium).

Pulmonary Disease in Cystic Fibrosis: Assessment with Chest CT at Chest Radiography Dose Levels

PURPOSE To investigate a computed tomographic (CT) protocol with iterative reconstruction at conventional radiography dose levels for the assessment of structural lung abnormalities in patients with cystic fibrosis ( CF cystic fibrosis ). MATERIALS AND METHODS In this institutional review board-approved study, 38 patients with CF cystic fibrosis (age range, 6-58 years; 21 patients <18 years and 17 patients >18 years) underwent investigative CT (at minimal exposure settings combined with iterative reconstruction) as a replacement of yearly follow-up posteroanterior chest radiography. Verbal informed consent was obtained from all patients or their parents. CT images were randomized and rated independently by two radiologists with use of the Bhalla scoring system. In addition, mosaic perfusion was evaluated. As reference, the previous available conventional chest CT scan was used. Differences in Bhalla scores were assessed with the χ(2) test and intraclass correlation coefficients ( ICC intraclass correlation coefficient s). Radiation doses for CT and radiography were assessed for adults (>18 years) and children (<18 years) separately by using technical dose descriptors and estimated effective dose. Differences in dose were assessed with the Mann-Whitney U test. RESULTS The median effective dose for the investigative protocol was 0.04 mSv (95% confidence interval [ CI confidence interval ]: 0.034 mSv, 0.10 mSv) for children and 0.05 mSv (95% CI confidence interval : 0.04 mSv, 0.08 mSv) for adults. These doses were much lower than those with conventional CT (median: 0.52 mSv [95% CI confidence interval : 0.31 mSv, 3.90 mSv] for children and 1.12 mSv [95% CI confidence interval : 0.57 mSv, 3.15 mSv] for adults) and of the same order of magnitude as those for conventional radiography (median: 0.012 mSv [95% CI confidence interval : 0.006 mSv, 0.022 mSv] for children and 0.012 mSv [95% CI confidence interval : 0.005 mSv, 0.031 mSv] for adults). All images were rated at least as diagnostically acceptable. Very good agreement was found in overall Bhalla score ( ICC intraclass correlation coefficient , 0.96) with regard to the severity of bronchiectasis ( ICC intraclass correlation coefficient , 0.87) and sacculations and abscesses ( ICC intraclass correlation coefficient , 0.84). Interobserver agreement was excellent ( ICC intraclass correlation coefficient , 0.86-1). CONCLUSION For patients with CF cystic fibrosis , a dedicated chest CT protocol can replace the two yearly follow-up chest radiographic examinations without major dose penalty and with similar diagnostic quality compared with conventional CT.

Management system for a PACS network in a hospital environment

The size of a typical data transfer in a PACS environment is several orders of magnitude larger than a typical data transfer in a local area computer network. PACS is also moving to a multi-vendor environment. To ensure reasonable response times to users, it is necessary to manage the image traffic on the PACS network explicitly, and for the heterogeneous network environment, tools for monitoring and maintenance are necessary. Modular network architectures, capable of reacting to growth and changes in traffic patterns, are essential. Knowledge about patient-radiologist and image flow which is available in the hospital environment can be exploited for careful planning and scheduling of network traffic. The authors designed and implemented a prototype network management system that makes the domain knowledge and the traffic management strategy explicit. In general, the term network management covers a wide range of tasks. Network design and configuration, for example, are network management tasks situated in the pre-operational phase. Network monitoring and control, including error detection, fault diagnosis, dynamic routing, etc., are network management tasks with a real-time aspect. This PACS is hierarchically organized. Each sub- department has its own local PACS. The paper focuses on the results of the implementation of the PACS architecture and, more precisely, on the network management aspects.

Design of a Generic HIS-RIS/PACS Interface based on the Radiodiagnostic Working Methods

The objective of the EurlPACS/HIPIN topic is to realize a generic HIS/RIS-PACS interface. The advantage of the generic interface concept is that it minimizes the efforts to realize a new instantiation of the HIPIN interface for a specific hospital. For a new instantiation only minimal adaptations in the software of the HIPIN interface itself and of the local HIS/RIS and PACS systems are required.

Radiography of the distal extremity of the manus in the donkey foal: Normal images and quantitative characterization from birth to 2 years of age: A pilot study

This study describes a radiographic survey of the anatomical development of the distal extremity of the manus in the donkey from 0 to 2 years of age. The right distal limb of 10 donkey foals, born in the spring of 2012, underwent radiographs every month for the first 6 months of age and every 3 months during the following 18 months. Latero‐medial radiographs with and without barium marker at the coronary band and dorso‐palmar radiographs with both front feet in weight bearing were obtained. The distal physis of the third metacarpal bone and the proximal physis of the proximal phalanx (phalanx proximalis) were closed at the mean age of 18.6 months. The distal physis of the proximal phalanx appeared as a clear radiolucent line at 2 weeks of age and was still subtly visible in some donkeys at 24 months. The proximal physis of the middle phalanx (phalanx media) was closed at the mean age of 16.7 months. The distal physis of this phalanx was visible at birth, but closed at 4 days. The distal phalanx (phalanx distalis) was triangular at birth. At the age of 20–21 months, the palmar processes (processus palmares) were both developed. The navicular bone (os sesamoideum distalis) was developed at the mean age of 9 months. The proximal sesamoid bones (ossa sesamoidea proximalia) were seen in continuously development during the 24 months. It seems that the physes in the distal extremity of the manus in the donkey close at an older age than the physes in the horse.

Comparison of Several White Matter Tracts in Feline and Canine Brain by Using Magnetic Resonance Diffusion Tensor Imaging

Recently, we published a first anatomical diffusion tensor imaging (DTI) atlas regarding white matter tracts in the canine brain. The purpose of this study was to show the significance of DTI in the revelation of the white matter fibres in the feline brain (i.e., to obtain an anatomical DTI atlas of images) and to descriptively compare these to previously obtained white matter fibre images of the canine brain. DTI MR Images of four cats euthanized for reasons other than neurological disorders were obtained with a 3 T system. Combined fractional anisotropic (FA) and directional maps were obtained within the hour after death. An experienced anatomist tracked white matter tracts of clinical relevance using the scanner software. After validation of these tracts, we compared relevant neurological connections between the cat and the dog. Comparison of cerebral structures between different species is easier when the three dimensional anatomy is visualized by using DTI. 3D rendered DTI images clearly show major differences in neurological architecture between cats and dogs for example, the more important space occupying role of the limbic system, and the less diffuse, less nodular, less pronounced and thinner fibre bundles in the feline brain compared to the canine brain (except for the cerebellum different parts connecting fibres passing through the brainstem which are pronouncedly developed). Anat Rec, 300:1270–1289, 2017.

Can an internet based clinical PACS be used as training tool

Purpose At our institute we organized a teaching environment enabling radiology and radioanatomy courses with today’s advanced 2D image reviewing and 3D image postprocessing to offer a state of the art environment to our Radiological Technologists in training, providing tools like MPR and VR [1]. Enabling students to handle large image sets remotely at home and during hands on courses. The advent of CT volume scanning did dramatically change our habit of image viewing and image postprocessing for our Radiological Technologists in training. Methods The original setup was created to support the teaching of the students at the medical faculty of the Vrije Universiteit Brussel. We agreed to share infrastructure of the teaching environment to the Hogeschool-Universiteit Brussel in order to enhance the skillslab setup. The vast amount of datasets originating from a clinical PACS are the building blocks for the educational anatomy and radiopathology training sets [2]. The image repository consists out of sufficient blinded image material. Native DICOM sets can be processed into MPR and VR sets. Teaching the Radiological Technologists takes place in skillslab at Hogeschool-Universiteit Brussel. The general purpose computers available in the skillslab are used as reviewing and processing stations. The courses on radiology and radioanatomy need to compete with other courses regarding the software installation. To avoid technical issues around compatibility of certain competing software and releases of products, we decided to apply a virtual environment. In this way we can freeze the correct software computer setting for our application without compromising the functionality of the other competing courses and vice versa. In the skillslab the students were dedicated to an individual client workstation during the practical lessons. On this client the student need to load and startup the prepared virtual machine from the server to start his learning session. At the Vrije Universiteit Brussel the general purpose thin clients classrooms were connected to a VMware server environment based on VMware Vsphere and VMware View software. The infrastructure is managed by the medical informatics department at the University College. Secondly the advanced setup was secured in order to provide teaching sets in reach over the internet for use at home [3]. Since hosting takes place on a central server, the hardware requirements of the remote client are minimal. The student had to install the VMWare client which runs on all latest versions of Windows, Mac and Linux platforms. This provides the students with a remote view on the virtual desktop; the communication between the client and the virtual desktops is based upon a secure remote desktop viewing protocol. With this approach the student is free to utilize his preferred computer system. By means of a standard internet connection the cases are available for analysis and processing at any time and at any place during their training. Results The teaching methods of the past where merely based on static presentation of images in text books and X-ray film based illustrations presented on lightboxes. In the interim period between film based, atlas viewing and the full digital system we did hand over the educational cases to the students on CD-R or DVD-R media, pointless to say that the production of those media were time-consuming and the access of these media was not very user friendly for the student. The profound change of teaching methods from plain atlas and hardcopy viewing to 3D sets was a difficult transition for some lecturers. After that transition period the lecturers were all convinced of the broader possibilities of the tools which enhanced the knowledge acquirements and improved abilities of image handling. Students embrace the possibilities of image processing and the possibilities to study their cases at their own speed and time. The 3D visualization did improve the understanding of complex anatomy training. The grades improved in field of anatomy and radiopathology Conclusions Without changing the infrastructure of our skillslab we were able to offer multiple applications such as advanced radiological viewing and image postprocessing. Once the infrastructure was tested and fully functional, the main job of the support team was on the server side. An upgrade of the iSite enterprise software will take place in the near future, which implies building a new virtual machine. When the virtual machine is fully tested, this environment can be redistributed in the computer classrooms. In an educational environment where possibly conflicting requirements in setup exist, this approach is highly appreciated by the teachers of different disciplines. The quality of our education program by means of the enhanced visualization is not only superior to the use of books and distributed CD-R, but is also more appreciated by the students. The ease of installation at the remote site and the possibility of use at home is certainly an added value for the students. The proposed system is nowadays an added value for students and lecturers. It will be part of the future teaching platform. We aim to extent its content and develop it into a base for our e-learning program. References [1] Silén, C., Wirell, S., Kvist, J., Nylander, E., & Smedby, O. (2008, Jun 30). Advanced 3D visualisation in student-centered medical education. Med Teach, pp. 115–124. [2] Turmezei, T., Tam, M., & Loughna, S. (2009, Sept 22). A survey of medical students on the impact of a new digital imaging library in the dissection room. Clin Anat, pp. 761–769. [3] Petersson, H., Sinkvist, D., Wang, C., & Smedby, O. (2009, Mar-Apr 2). Web-based interactive 3D visualization as a tool for improved anatomy learning. Anat Sci Educ, pp. 61– 68.

Multilevel use of image repository in the field of veterinary imaging and dissemination of training tools

Purpose At our institute we organized a teaching environment enabling radiology and radioanatomy courses with today’s advanced 2D image reviewing and 3D image postprocessing to offer a state of the art environment to our Radiological Technologists in training, providing tools like MPR and VR [1]. Enabling students to handle large image sets remotely at home and during hands on courses. The advent of CT volume scanning did dramatically change our habit of image viewing and image postprocessing for our Radiological Technologists in training. Methods The original setup was created to support the teaching of the students at the medical faculty of the Vrije Universiteit Brussel. We agreed to share infrastructure of the teaching environment to the Hogeschool-Universiteit Brussel in order to enhance the skillslab setup. The vast amount of datasets originating from a clinical PACS are the building blocks for the educational anatomy and radiopathology training sets [2]. The image repository consists out of sufficient blinded image material. Native DICOM sets can be processed into MPR and VR sets. Teaching the Radiological Technologists takes place in skillslab at Hogeschool-Universiteit Brussel. The general purpose computers available in the skillslab are used as reviewing and processing stations. The courses on radiology and radioanatomy need to compete with other courses regarding the software installation. To avoid technical issues around compatibility of certain competing software and releases of products, we decided to apply a virtual environment. In this way we can freeze the correct software computer setting for our application without compromising the functionality of the other competing courses and vice versa. In the skillslab the students were dedicated to an individual client workstation during the practical lessons. On this client the student need to load and startup the prepared virtual machine from the server to start his learning session. At the Vrije Universiteit Brussel the general purpose thin clients classrooms were connected to a VMware server environment based on VMware Vsphere and VMware View software. The infrastructure is managed by the medical informatics department at the University College. Secondly the advanced setup was secured in order to provide teaching sets in reach over the internet for use at home [3]. Since hosting takes place on a central server, the hardware requirements of the remote client are minimal. The student had to install the VMWare client which runs on all latest versions of Windows, Mac and Linux platforms. This provides the students with a remote view on the virtual desktop; the communication between the client and the virtual desktops is based upon a secure remote desktop viewing protocol. With this approach the student is free to utilize his preferred computer system. By means of a standard internet connection the cases are available for analysis and processing at any time and at any place during their training. Results The teaching methods of the past where merely based on static presentation of images in text books and X-ray film based illustrations presented on lightboxes. In the interim period between film based, atlas viewing and the full digital system we did hand over the educational cases to the students on CD-R or DVD-R media, pointless to say that the production of those media were time-consuming and the access of these media was not very user friendly for the student. The profound change of teaching methods from plain atlas and hardcopy viewing to 3D sets was a difficult transition for some lecturers. After that transition period the lecturers were all convinced of the broader possibilities of the tools which enhanced the knowledge acquirements and improved abilities of image handling. Students embrace the possibilities of image processing and the possibilities to study their cases at their own speed and time. The 3D visualization did improve the understanding of complex anatomy training. The grades improved in field of anatomy and radiopathology Conclusions Without changing the infrastructure of our skillslab we were able to offer multiple applications such as advanced radiological viewing and image postprocessing. Once the infrastructure was tested and fully functional, the main job of the support team was on the server side. An upgrade of the iSite enterprise software will take place in the near future, which implies building a new virtual machine. When the virtual machine is fully tested, this environment can be redistributed in the computer classrooms. In an educational environment where possibly conflicting requirements in setup exist, this approach is highly appreciated by the teachers of different disciplines. The quality of our education program by means of the enhanced visualization is not only superior to the use of books and distributed CD-R, but is also more appreciated by the students. The ease of installation at the remote site and the possibility of use at home is certainly an added value for the students. The proposed system is nowadays an added value for students and lecturers. It will be part of the future teaching platform. We aim to extent its content and develop it into a base for our e-learning program. References [1] Silén, C., Wirell, S., Kvist, J., Nylander, E., & Smedby, O. (2008, Jun 30). Advanced 3D visualisation in student-centered medical education. Med Teach, pp. 115–124. [2] Turmezei, T., Tam, M., & Loughna, S. (2009, Sept 22). A survey of medical students on the impact of a new digital imaging library in the dissection room. Clin Anat, pp. 761–769. [3] Petersson, H., Sinkvist, D., Wang, C., & Smedby, O. (2009, Mar-Apr 2). Web-based interactive 3D visualization as a tool for improved anatomy learning. Anat Sci Educ, pp. 61– 68.