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Biomedical subjects

B Maldague

Publications and source records attributed to B Maldague.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Radiology and emergency medicine: state of the art].

Emergency medicine has emerged as a specific medical specialty for 30 years. To be efficient, the emergency clinician frequently needs the contribution of radiological examinations. This is the reason why emergency radiology has emerged as a new radiologic subspecialty. The aim of this paper is to review the recent history of emergency medicine and to summarize the present state of the radiological organisation for emergency care in the Western countries.

Emergency Medicine↗
PubMed1998

Magnetic resonance imaging of the normal bone marrow.

The bone marrow is a complex organ that contains fat and nonfat cells, the proportions of which vary greatly with age and in the different bones of the skeleton. Magnetic resonance (MR) imaging provides information on the composition of the medullary cavity of any given bone and on the distribution of red and yellow marrow in the skeleton. This article deals with the wide spectrum of appearances of the normal bone marrow at MR imaging.

Adipocytes↗
PubMed1998

Classification and detection of bone marrow lesions with magnetic resonance imaging.

A logical approach to bone marrow alterations is proposed that takes into account the high sensitivity and specificity of MR imaging for the detection of marrow fat. Marrow signal intensity on T1-weighted images is assumed to reflect the balance between fat and nonfat marrow components. Elementary patterns of marrow change include marrow depletion, infiltration, replacement and signal void. These patterns can be observed alone or in combination, and can be distributed in a focal or diffuse manner. Marrow depletion pattern shows high signal intensity reflecting increase in fat content and is frequently irrelevant clinically. Signal intensity is decreased in marrow infiltration, replacement and signal void patterns, which indicates partial or complete disappearance of fat. Focal marrow infiltration is frequently reactive to an adjacent abnormality, whereas focal marrow replacement more frequently indicates a more profound marrow alteration. The T1-weighted spin-echo sequence is satisfactory for lesion detection by virtue of its relatively high sensitivity in the detection of altered fat/nonfat marrow balance. T2-weighted sequences with saturation of the signal of fat protons or out-of-phase gradient-echo sequences improve lesion conspicuity in all situations in which the difference in fat/nonfat marrow balance between the abnormal area and the adjacent normal marrow is reduced.

Adult↗
PubMed1998

Magnetic resonance imaging of normal bone marrow.

The appearance in magnetic resonance imaging (MRI) of the bones depends, to a large extent, on the unmineralized content of the bone cavities. Because yellow marrow contains a large number of fat protons and red marrow a significant number of water protons, MRI offers the opportunity to map the distribution of red and yellow marrow. In addition, red marrow MR appearance varies according to the relative proportion of fat and nonfat cells. Variations in the composition of red marrow and its distribution among normal subjects, mainly in relation to age and sex, contribute to creating a wide spectrum in bone MR appearance, which must be known in order to avoid confusion with bone marrow abnormalities.

Adipose Tissue↗
PubMed1998

Magnetic resonance imaging of the bone marrow in hematological malignancies.

Despite its lack of specificity, magnetic resonance imaging (MRI) of the bone marrow has the potential to play a role in the management of patients with primary neoplastic disorders of the hematopoietic system, including lymphomas, leukemias and multiple myeloma. In addition to its use in the assessment of suspected spinal cord compression, bone marrow MRI could be used as a prognostic method or as a technique to assess the response to treatment. The current review addresses the common patterns of bone marrow involvement observed in primary neoplasms of the bone marrow, basic technical principles of bone marrow MRI, and several applications of MRI in selected clinical situations.

Adolescent↗
PubMed1998

Interactive DICOM image transmission and telediagnosis over the European ATM network.

The European High-Performance Information Infrastructure in Medicine, n(o)B3014 (HIM3) project of the Trans-European Network--Integrated Broadband Communications (TEN-IBC) program, started on March 1996 and finished on February 1997, aimed to test the medical usability of the European asynchronous transfer mode (ATM) network in medical image transmission. The Department of Radiology, University of Pisa, Pisa, Italy, and St-Luc University Hospital, Brussels, Belgium, involved in the project as healthcare partners in the radiological domain, established several connection sessions finalized to test the usability of Digital Imaging and Communication (DICOM) image transmission and interactive telediagnosis tools in the daily radiological practice. The Pisa site was connected to the Italian ATM pilot (Sirius Network) through the Tuscany metropolitan area network (MAN), while St-Luc University Hospital was connected to Belgium ATM network through the Brussels MAN. By means of international connections provided by the European JAMES project, a link between the two sites was established, connecting both national ATM networks. Due to the large variety of hardware present in the medical centers, multiplatform software tools were used and tested: central test node (CTN) release 2.8 [3], VAT [6], NV-3.3 [7], and IDI (UCL homemade multiplatform teleradiology tool for interactive visualization and processing of DICOM images). During the telediagnosis session, lead by radiologists in both hospitals, each site submitted neuroradiological clinical cases to the other for remote consultation. The connection, available for a period of two weeks, at 2-Mbit/s bandwidth, allowed the transmission of MR images (256 x 256 x 12 bit) and simultaneous multimedia interactive discussion of the cases. Both off-line transmission and review of the images, using the CTN DICOM transfer routines, and on-line interactive image discussion, using the IDI telediagnosis software, were tested successfully from the technical and medical point of view.

Computer Communication Networks↗
PubMed1998

[Ultrasonography of dorsal elastofibroma. Apropos of 6 cases].

Elastofibroma dorsi is a benign soft-tissue tumor. Its sub- and pre-scapular location and its appearance on CT and MRI generally lead to the diagnosis. We have analyzed with sonography 6 elastofibromas in 4 patients; the diagnosis was confirmed with CT scan or MRI. Some sonography imaging features supported the diagnosis of elastofibroma dorsi. In all the cases, (1) the tumor occurred typically in a sub- and pre-scapular location, and (2) showed a streaky echostructure (3). A similar symptomatic or asymptomatic mass in the opposite subscapular location is highly suggestive.

Aged↗
PubMed1997

Effects of riluzole on the evolution of focal cerebral ischemia: a magnetic resonance imaging study.

The aim of this study was to investigate the effects of riluzole on the lesion induced by a permanent middle cerebral artery occlusion (MCAO) in rats. Riluzole at 4 or 8 mg/kg i.v. significantly reduced the cortical ischemic brain damage. With the most effective dose of 8 mg/kg, the time evolution of the lesion was assessed by T2-weighted magnetic resonance imaging (MRI) repeated on the same animals after MCAO. MRI obtained at 24, 48, and 72 hours after MCAO showed a progressive increase of the ischemic lesion, except in the cortex of the riluzole-treated rats (8 mg/kg i.v.). Furthermore, there was no difference between lesion volumes as measured by MRI or by histology. This study indicates that MRI may be a valuable method to quantify in vivo the neuroprotective profile of a drug.

Animals↗
PubMed1997

MR assessment of red marrow distribution and composition in the proximal femur: correlation with clinical and laboratory parameters.

OBJECTIVE: To correlate the MR appearance of the proximal femur marrow with clinical and blood parameters. DESIGN AND PATIENTS: The proportion of the femoral neck surface area occupied by red marrow was determined on T1-weighted magnetic resonance (MR) images of the hip in a series of 120 subjects, aged from 15 to 75 years, with ten females and ten males per decade, and correlated with clinical data. This parameter and the bulk T1 values of femoral red marrow were determined in 30 other subjects 25-46 years of age and correlated with their blood parameters. RESULTS: In the series of 120 subjects, the proportion of red marrow surface area decreased with age (P < 10(-4)) and was higher in female than male subjects (P < 10(-4)). Within each decade, the proportion of red marrow surface area was higher in females than in males between 25 and 65 years but neither before 25 nor after 65 years. In the series of 30 subjects, the proportion of red marrow surface area and bulk T1 values of femoral red marrow were significantly negatively correlated with hemoglobin blood levels but not with blood cell counts. CONCLUSION: The MR appearance of proximal femur red marrow is influenced by age and sex. A relationship with hemoglobin blood level is demonstrated.

Adolescent↗
PubMed1997

Detection of reperfused ischemia of the rat intestine: value of magnetic resonance imaging with small-molecular-weight dysprosium and gadolinium chelates.

RATIONALE AND OBJECTIVES: The authors assessed whether the small-molecular-weight magnetic resonance (MR) imaging contrast agents dysprosium diethylenetriamepentaacetic acid bismethylamide (sprodiamide injection), which enhances T2*, and gadolinium diethylenetriamepentaacetic acid bismethylamide (gadodiamide injection), which enhances T1, could improve the detection of reperfused ischemia of the rat intestine. METHODS: Eighteen rats were subjected to vascular occlusion of the distal ileum for 30 minutes, followed by reperfusion. Ten minutes after reperfusion, T1- and T2-weighted spin-echo (SE) images were obtained before and after administration of sprodiamide, gadodiamide, or both. The same imaging protocol was applied in another group of 18 rats subjected to 10 minutes of occlusion and reperfusion. Histologic examination of the intestine was performed after MR imaging. RESULTS: Villous injury (ie, denudation) was observed in most cases after 30 minutes of occlusion, but not after 10 minutes of occlusion. After 30 minutes of occlusion, the superficial part of the ischemic intestine was hyperintense to the normal intestine on unenhanced T2-weighted images. Administration of sprodiamide improved the contrast between the normal and ischemic intestine on T2-weighted images, and administration of both gadodiamide and sprodiamide improved the contrast on T1- and T2-weighted images. After 10 minutes of occlusion, no contrast was discernible before or after contrast material administration. CONCLUSION: These results suggest that the detection of reperfused intestinal ischemia of sufficient duration to cause villous injury can be improved by using sprodiamide injection alone or in combination with gadodiamide.

Animals↗
PubMed1997

Long-term effects of localized spinal radiation therapy on vertebral fractures and focal lesions appearance in patients with multiple myeloma.

The occurrence of new vertebral fractures and focal marrow lesions was determined and compared in irradiated and nonirradiated vertebrae of 12 patients with multiple myeloma (MM), prospectively followed using magnetic resonance imaging (MRI) of the thoraco-lumbar spine after localized spinal radiation therapy. During follow-up (mean 35 months), fractures appeared in 5% of irradiated vertebrae and in 20% of nonirradiated vertebrae: new focal lesions appeared in 4% of irradiated vertebrae and in 27% of nonirradiated vertebrae. This study demonstrates a beneficial long-term effect of localized radiation therapy, consisting of a reduced incidence of vertebral fractures and focal marrow lesions in irradiated vertebrae.

Aged↗
PubMed1997

MR imaging of bone infarction and epiphyseal osteonecrosis.

No single musculoskeletal disorder has generated more passionate discussion than bone osteonecrosis. Surprisingly, its physiopathogenesis remains largely unknown despite in-depth studies. Its treatment is still debated, and its wide range of clinical manifestations which vary from totally asymptomatic to the catastrophic event of irreversible epiphyseal collapse remains a fascinating question for the clinicians (1-4). Magnetic Resonance (MR) imaging has given a large tribute to the discussion during the last decade by allowing detection of marrow infarcts at a presymptomatic period of the disease, thus providing data on its natural history. Unfortunately, MR imaging has also contributed to increase the confusion among various epiphyseal disorders. The aim of the current paper is to provide an overview of the current knowledge of imaging features by stressing accepted data and delineating blind areas.

Adolescent↗
PubMed1997

[Radiologic aspects of the loosening of cemented hip prostheses: mechanical, septic or granulomatous etiology?].

Radiologic diagnosis of hip prosthesis loosening is based on the evaluation of each component (prosthesis, cement, bone) and of their interfaces. Both the prosthesis and the cement may deteriorate and the prosthesis/cement interface or cement/bone interface may become abnormal in prosthesis loosening of any etiology. In contrast, the aspect of the bone changes (erosion, periostitis) and their distribution vary according to the condition etiology. It appears from a retrospective study of 50 cases of chronic hip prosthesis loosening that the most specific signs for infection are unsharp bone resorption and acute-like or multifocal periostitis. In granulomatous loosening, bone resorption is sharp (as in mechanical loosening), but its distribution is not conform to the prosthesis shape (as in septic loosening), and periosteal changes are not observed.

Arthroplasty, Replacement, Hip↗
PubMed1995

[Quality control in pediatric radiology].

The authors recall the fundamentals of an adequate use of the X-rays considering to the ALARA (As Low As Reasonably Achievable) principle. The article deals more specifically with radiation protection and quality control in radiopediatrics, as this age group is essentially concerned with stochastic hazards, i.e. cancer induction and genetic injurious effects. The major elements of X-ray equipment are reviewed, including the X-ray generator, device, film-screen, radiogenic tube, automatic exposure device, and so on... The influence of technical parameters on dosimetry in terms of radiation protection as well as dosis variation, according to the type of disorder, are demonstrated. Reference is made to the radiologic techniques proposed by the Lake Starnberg Group.

Child↗