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M Osteaux

Publications and source records attributed to M Osteaux.

At least 19 recordsLinked to original sources
PubMed1996

MRI of anatomical variants of the wrist in women.

In the analysis of magnetic resonance (MR) images of the wrist joint, some structural variations may lead to misinterpretation. Our aim was to search for different anatomical variants and their MR characteristics on axial images. Two groups of patients with rheumatoid arthritis (thirty one) and carpal tunnel syndrome (sixty two), and a group of asymptomatic controls (fifty four) underwent bilateral MR axial wrist imaging from the metacarpal bases to the distal radiocarpal joint. The imaging techniques included spin echo (SE), turbo spin echo (TSE) and fast field echo (FFE) sequences, using 3 mm-slice thickness. Different anatomical variants including hypoplasia of the hamulus or hook of the hamate bone (4 cases), anomalous muscles (lumbricals) inside the carpal tunnel (2 cases), unusual location (5 cases) and double branching of the median nerve (14 cases), and aberrant median artery (one case) were detected. These variants, if unfamiliar to MR readers, may be misinterpreted as pathological features.

Adolescent↗
PubMed1996

Picture archiving and communication system (PACS): a progressive approach with small systems.

PACS represents the natural evolution from working with digital modalities (e.g. CT, US, MRI, CR) towards a global digital environment where the film based activities are progressively replaced by their digital counterpart. The advantages of the technique and the drawbacks of the first implementations are described, as well as the recent advances in terms of technology, architecture, medical integration and cost-effectiveness. The so called 'second generation' PACS concept is presented with its features: modular architecture, progressive implementation, multi-vendor environment, integration with the Hospital Information System, standardization. This approach is particularly suited for progressive implementation in an existing hospital, in contrast to the possible top-down construction of a filmless radiology department, as a project for a totally new hospital. The implementation into the university hospital AZ-VUB is described as case study.

Radiology Department, Hospital↗
PubMed1996

Quantification of trabecular structure in the distal femur using magnetic resonance phase imaging.

A new approach for quantifying trabecular bone tissue using the phase images of a simple gradient-echo sequence is presented. The proposed method is based on the hypothesis that the differences in susceptibility between bone and bone marrow cause magnetic field (i.e., precession phase) variations between the image voxels. Phase images of the distal femur were obtained in vivo and characterised with the use of the phase variance. Computer simulations and experimental results indicate that the distribution of the phases varies with echo time and image resolution, as expected. Keeping these fixed, however, the phase variance is found to strongly reflect variations in trabecular structure.

Adult↗
PubMed1996

Cortical and total bone mineral content of the radius: accuracy of peripheral computed tomography.

The aim of the study was to evaluate the accuracy of an XCT 960 Stratec peripheral quantitative computed tomography (pQCT) device in assessing bone mineral content of the radius. We scanned 27 left forearm specimens excised from cadavers and focused on cortical bone mineral content (BMCc) at the junction of the middle and distal third and on total bone mineral content (BMCtot) at the distal end of the radius. Cylindrical specimens matched with those two sites were cut using a diamond circular saw, embedded in a polyester resin and subsequently submitted to two reference methods, nondestructive neutron activation analysis and flame atomic absorption spectrometry. Mineral contents measured by pQCT were closely correlated with those assessed by using the two reference methods, with correlation coefficients ranging from 0.862 to 0.960. The standard error of the estimate amounted 7-10% for the BMCc (junction of the middle and distal third), and 17-18% for the BMCtot (distal end). We conclude that pQCT is able to measure either cortical or total mineral content of the radius with a high degree of accuracy.

Aged↗
PubMed1996

Jejunal stromal tumor.

A case of jejunal stromal tumor is reported. Clinical findings included melena, syncope, and palpable abdominal mass. CT scans showed an abdominal mass with characteristics simulating an intra-abdominal abscess.

Aged↗
PubMed1995

Time resolved flow quantification with MRI using phase methods: a linear systems approach.

Phase-related unsteady (pulsatile) flow effects in MRI have been studied by means of linear response theory. These flow effects can be described in the frequency domain: the influence of the gradients on the phase shift is described by a transfer function, the spectrum of the gradient being the determining factor. An analysis of this transfer function is shown to provide information about the process of flow encoding: instant of encoding, induced distortions and how they are related to the gradient waveform. The connection with the traditional description in terms of the gradient moment expansion has also been investigated and clarified. This approach was applied to study the response of two time-resolved flow quantification techniques (Fourier flow method and phase mapping) by analyzing their amplitude and phase transfer functions. By simulation it is shown that a better interpretation of the measured velocity waveform is obtained and that Fourier analysis in combination with a correction by the inverse transfer function results in an accurate reconstruction of the velocity waveform studied.

Algorithms↗
PubMed1995

Cortical thickness assessed by peripheral quantitative computed tomography: accuracy evaluated on radius specimens.

The purpose of the present study was to evaluate the accuracy of peripheral quantitative computed tomography (pQCT) in measuring the thickness of the radial cortex. Thirty left forearm specimens were scanned on an XCT 960 Stratec pQCT device using a 2.5 mm thick slice at the junction of the middle and the distal third of the radius. Cortical and trabecular areas were assessed using a threshold procedure; cortical thickness was subsequently calculated assuming a circular ring model for the radius. Cortical thickness was also measured on the true shape of bone using an iterative contour detection procedure. Subsequently 2.5 mm thick resin-embedded cylindrical radial specimens, matched with the site of pQCT examination, were obtained and contact radiographs were performed. After tenfold magnification, the cortical and trabecular areas of the specimens were measured using computerized planimetry and cortical thickness was calculated assuming a circular ring model. The cortical thickness could be assessed by pQCT in all cases using the threshold algorithm (mean (SD) 2.51 (0.58) mm) and in 21 cases could be directly measured on the true shape of bone (2.62 (0.32) mm). The cortical thickness of the specimens showed good correlation and high proportionality with that measured using pQCT with either the threshold algorithm (r = 0.941, slope = 0.976) or the iterative contour detection procedure (r = 0.883, slope = 0.987). In conclusion, pQCT is able to assess the thickness of the radial cortex, at the junction of the middle and the distal third, with high accuracy.

Aged↗
PubMed1995

A vein of Galen aneurysm with an abnormal drain system: MRI findings.

The case of a premature girl with a vein of Galen aneurysm is reported. The lesion was detected by ultrasonography. MRI provided complete anatomical information, obviating the need for initial angiography for preoperative evaluation of the malformation. Venous drainage through a persistent embryonic falcine sinus and associated atresia of the straight sinus could be identified, while venous thrombosis and parenchymal damage could be excluded.

Carotid Arteries↗
PubMed1995

Cortical mineral content of the radius assessed by peripheral QCT predicts compressive strength on biomechanical testing.

Our aim was to evaluate the role of cortical bone in resistance to compression in the human radius. Thirty-three left cadaver forearms were scanned on an XCT 960 Stratec CT scanner. Cortical density and cortical thickness were measured at the junction of the middle and distal third of the radius. Subsequently, 2-cm-high cylindrical specimens, centrated on the level of the CT slice, were cut. After removal of the endosteal trabecular bone, the specimens were submitted to compressive testing, using an Instron machine, and load deformation curves were obtained. Maximal stress (load corrected for cross-sectional area) showed a significant relationship with the density (r = 0.78) as well as with the thickness (r = 0.74) of the cortex. The closest correlation involved the maximal load and the mineral content of the cortex specimens (r = 0.87). We conclude that the mineral content of these radius cortex specimens, measured using peripheral QCT, predicts their compressive strength on biomechanical testing.

Aged↗
PubMed1995

Percutaneous needle biopsy of localized pulmonary, mediastinal, and pleural diseased tissue with an automatic disposable guillotine soft-tissue needle. Preliminary results.

Percutaneous needle biopsy (PNB) of localized thoracic disease has become a widespread procedure in many institutions. The development of special small caliber needles has increased the diagnostic yield of PNB partly by increasing the amount of tissue from biopsy, often enabling histologic examination. Nevertheless, in a significant number of patients only cytopathologic examination is possible on the retrieved biopsy fragments, necessitating the presence of a trained cytopathologist in the biopsy room. Furthermore multiple biopsy needle passages often are required, increasing the risk for complications such as pneumothorax. We have evaluated the use of a small-caliber tissue biopsy cutting needle, consistently yielding sufficient biopsy tissue for histologic examination. In 25 pleural and mediastinal lesions, which could be biopsied without passage through aerated lung, there was a 93% sensitivity (7% false-negative results) for neoplasm and a 100% accuracy for benign disease. There were no complications. In 32 patients with lesions of 1 cm in diameter or more surrounded with aerated lung tissue, adequate histologic examination was feasible on every biopsy specimen after only one needle passage. There was an 87% sensitivity of PNB in neoplastic disease (13% false-negatives). In the patients with benign disease, there was a 100% accuracy. There was a 15.6% risk for pneumothorax. In only one patient (3%), however, was chest drainage necessary. One patient (3%) had mild hemoptysis. We conclude that percutaneous biopsy of localized pulmonary, pleural, and mediastinal lesions with a new small-caliber automatic guillotine cutting needle is safe and efficient, enabling recovery of sufficient tissue for histologic examination with a single-pass procedure, thus minimizing the risk for pneumothorax, eliminating the need for a cytopathologist in the biopsy room, and shortening the duration of the procedure.

Adult↗
PubMed1995

[Spiral CT of vascular liver lesions].

Computed tomography (CT) has an important and undisputed role as a screening modality for suspected focal liver disease. Improvements in CT technology have dramatically increased our ability to detect and diagnose liver abnormalities. Spiral CT allows rapid imaging of the liver, resulting in improved contrast dynamics compared to conventional CT techniques. The timing of contrast administration and scan acquisition has become critical. With inadequate timing, lesions that in optimal conditions are easily visualized, can be ignored. Arterial phase imaging should be used when potential hypervascular neoplasms are suspected, and if possible, should include both arterial and portal venous phase imaging to ensure maximal lesion detection and visualisation of vascular structures. Portal venous phase imaging alone is optimal for evaluating most hypovascular tumors. This article reviews the principles of lesion detection and, to a lesser degree, lesion characterization. Special interest is focused on hypervascular lesions.

Carcinoma, Hepatocellular↗
PubMed1995

Quality control in mammography: practical implications.

The programme "Europe against cancer" stimulated, among other activities, breast screening activities in the member states. From the beginning, it was clear that a rigorous and efficient approach required the highest possible quality of the three major components of a breast screening programme: the medical performance (correct positioning, training of the medical staff, double reading of the mammograms and feedback from the pathologist and the epidemiologist), the organisation (attendance rate, data base) and the quality of the imaging process (compliance of the image quality and the breast dose with the CEC document of 1990). The first part of this paper will be limited to the latter component and the second part to the subject of correct positioning of the breast.

Female↗
PubMed1995

A rare cause of rickets in a young child.

We present a case of nutritional rickets in a young child due to a macrobiotic diet. The child presented with important thoracic deformation and breathing difficulties. Plain radiographs appeared to be an excellent method for the diagnosis and follow-up of the bony lesions in this disorder. We describe the typical bony abnormalities related to this relative rare disease.

Calcium, Dietary↗
PubMed1995

Technical quality control in mammography screening: first results in Belgium.

In this paper the first results of the application in Belgium of the European protocol for the technical quality control of mammography screening are presented. Twelve mammography screening units were submitted to an acceptance test: one fourth complied with the criteria after a second visit. A daily quality control procedure has been run since eighteen months. The most important detected problems are given and discussed. The European Commission, in the framework of "Europe Against Cancer", recently published the "European Guidelines for Quality Assurance in Mammography Screening" (1). In another contribution (2), a brief overview of the important appendix "European Protocol for the Quality Control of the Technical Aspects of Mammography Screening" was given. In this paper the first results for the application of this protocol in Belgium are presented.

Female↗
PubMed1995

Transvaginal duplex ultrasound in oncological gynecology.

In the evaluation of the female pelvis, sonography in general complements the physical examination of the patient. The goal is to differentiate normal features from pathophysiological lesions, inflammatory processes and tumoral masses, the latter ones either being benign or malignant. Transvaginal sonography is now generally considered as a more specific and more advanced diagnostic procedure than abdominal sonography. The ability to assess flow to and within the pelvic organs and masses using Doppler, expands the contribution of transvaginal ultrasound to the patho-physiologic parameters. The growth of new vessels or the development of existing ones forms a common thread throughout many areas of reproductive pathophysiology. Duplex transvaginal ultrasound will allow us to document some events in these areas. Since unrestricted tumor growth is dependent upon angiogenesis, transvaginal duplex ultrasound has thus been proposed to enhance the ultrasound specificity for gynecological cancer. However, similar processes of angiogenesis and thus Doppler features, can be observed during normal physiological events. To avoid confusion, morphological and Doppler features have to be carefully combined. This paper will emphasize on the relative contributions of each of them and the possible pitfalls.

Abscess↗
PubMed1995

From archives to picture archiving and communications systems.

Keeping organised and consistent film archives is a well-known problem in the radiological world. With the introduction of digital modalities (CT, MR,...) the idea of archiving the image data in a non common way was born. The aim is to keep the information in digital form from acquisition to destination, e.g. archives, viewing station, teleradiology, a task that was not as easy as some people believed, due to bare technical possibilities and to the lack of standards concerning medical image data. These reasons made it not so common to integrate components of different origins into a digital Picture Archiving and Communication environment. How should we attempt to integrate the analogue examinations? It is ridiculous to exclude the conventional XR-examination that accounts for more than 70% of the total production. We believe that there will be a migration to light-stimulable phosphor plates, but these are not yet user friendly and certainly not cost effective. We have similar problems of immature technology as we had for the digital modalities. In a first attempt the bridge can be crossed, between the two worlds by means of converters (laser scanner, CCD camera). PACS will become a reality in the future as almost all examinations will be digitalized. We are now in a transition period with its inconveniences, but we will gain a lot soon. The migration from piles of films through a computer assisted radiological archiving system to a full digital environment is sketched in a historical survey.

Radiology↗