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Biomedical subjects

M Osteaux

Publications and source records attributed to M Osteaux.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Transbrachial approach for aortic and selective supraaortic vessel catheterization using a safe and easy technique to reform the Simmons II catheter tip.

A total of 286 patients (158 outpatients) were examined by intra-arterial DSA in the evaluation of cerebrovascular disease using a transbrachial approach. In all cases a 5F introducer sheath, a 5F pigtail catheter for aortic arch injection and a 5F Simmons II catheter for selective catheterization were used. Excellent demonstration of aortic arch and supraaortic arteries (including intracranial circulation) was obtained (92.2-100%). The complication rate was favorable, with only one major complication (thrombosis of an axillary artery). The use of an introducer sheath minimizes local complications and vessel wall damage during catheter exchange. Aortic arch injection must always be performed prior to selective catheterization. The results of selective catheterization prove the suitability of the Simmons II catheter, whose typical shape was easily and safely obtained using the configuration of the pigtail catheter and a 180 cm long guide wire for catheter exchange. Using the technique as described, the transbrachial approach is a safe and easy way for optimal vascular evaluation in cerebrovascular disease, especially useful in outpatients.

Adult↗
PubMedDate not supplied

Fat fraction of lumbar bone marrow using in vivo proton nuclear magnetic resonance spectroscopy.

Localized proton spectra of the human lumbar vertebral body were recorded in vivo at 1.5 T, using the STEAM (stimulated echo acquisition mode) pulse sequence. Thirty-seven patients (18 men, 19 women) were examined, ranging in age from 21 to 68 years (mean = 40, SD = 13). The fat fraction of the bone marrow was calculated from the areas of the fat and water peaks in the spectrum. The results demonstrate that, in the course of aging, there is a systematic increase in measured fat percentage of about 7% per decade of age. No sex difference could be established on the basis of our results.

Adult↗
PubMedDate not supplied

Mineral content of vertebral trabecular bone: accuracy of dual energy quantitative computed tomography evaluated against neutron activation analysis and flame atomic absorption spectrometry.

The goal of this study was to evaluate the accuracy of preprocessing dual energy quantitative computed tomography (QCT) for assessment of trabecular bone mineral content (BMC) in lumbar vertebrae. The BMC of 49 lumbar vertebrae taken from 16 cadavers was measured using dual energy QCT with advanced software and hardware capabilities, including an automated definition of the trabecular region of interest (ROI). The midvertebral part of each vertebral body was embedded in a polyester resin and, subsequently, an experimental ROI was cut out using a scanjet image transmission procedure and a computer-assisted milling machine in order to mimic the ROI defined on QCT. After low temperature ashing, the experimental ROIs reduced to a bone powder were submitted to either nondestructive neutron activation analysis (n = 49) or to flame atomic absorption spectrometry (n = 45). BMC obtained with neutron activation analysis was closely related (r = 0.896) to that derived from atomic absorption spectrometry, taken as the gold standard, with, however, a slight overestimation. BMC values measured by QCT were highly correlated with those assessed using the two reference methods, all correlation coefficients being > 0.841. The standard errors of the estimate ranged 47.4-58.9 mg calcium hydroxyapatite in the regressions of BMC obtained with reference methods against BMC assessed by single energy QCT, 47.1-51.9 in the regressions involving dual energy QCT. We conclude that the trabecular BMC of lumbar vertebrae can be accurately measured by QCT and that the superiority in accuracy of dual energy is moderate, which is possible a characteristic of the preprocessing method.

Aged↗
PubMedDate not supplied

Evaluation of lower back pain with bone scintigraphy and SPECT.

Bone scintigraphy and single photon emission computed tomography (SPECT) may be performed for evaluation of lower back pain, especially when a bone abnormality is suspected. Various patterns of tracer activity based on precise identification of the anatomic location of increased uptake may be observed and used to evaluate bones and joints. Lesions centered about the disk space and vertebral body include spondylodiskitis, metastatic disease, vertebral body fracture, and degenerative disease (disk disease, spondylosis deformans). In diskitis, tracer uptake has a vertical orientation. Metastatic involvement should be suspected in solitary lesions evaluated with SPECT when the area of increased uptake extends from the vertebral body into the pedicle. Fractures are seen on planar and SPECT images as a linear, horizontally oriented area of increased uptake centered in the vertebral body. In degenerative disease, increased uptake is centered about the disk space and may be seen in and project beyond the surface of the vertebral body. Lesions of the posterior arch (comprising the pedicle, lamina, and facet joints) include spondylolysis, pedicle lesions, osteoarthritis of the facet joints, and fracture of the transverse process. Scintigraphy may help differentiate long-standing asymptomatic spondylolysis from ongoing disease. In osteoarthritis of the facet joints, SPECT may be used to select patients to be treated with therapeutic injections. Increased uptake in the transverse process most often indicates a fracture, although tumors may also occur in this location. These findings at planar bone scintigraphy and SPECT allow differentiation of common pathologic conditions and can lead to a specific diagnosis.

Humans↗
PubMedDate not supplied

Diffusion-weighted MR imaging of an acute venous stroke: case report.

A patient with a superior sagittal sinus thrombosis had progressively worsening symptoms and signs that resolved after IV heparin therapy. MR imaging revealed abnormalities in diffusion, similar to those seen with acute arterial stroke. Abnormalities shown on a T2-weighted fast spin-echo and fluid-attenuated inversion recovery images resolved completely. The findings in this report contradict those from previous reports that suggest diffusion-weighted imaging with quantitative apparent diffusion coefficients may be used in selecting patients for dural venous sinus thrombolysis.

Adult↗
PubMedDate not supplied

The use of phantoms or tissue simulating test objects in the evaluation of imaging methods.

We reviewed the 1996 issues of Radiology and American Journal of Roentgenology to appreciate the number of phantom studies published. There were 11 studies involving living animals and 51 other phantom studies. The categories chest, CT and MR, and musculoskeletal contained more than 10% of phantom studies in both journals. Design, advantages and limitations of different types of phantom studies are further addressed. Phantom studies offer several advantages over studies in patients in selected circumstances and have an important role in radiology research.

Animals↗
PubMedDate not supplied

MR imaging findings of bone marrow changes in patients with cystic fibrosis.

The purpose of this work was to evaluate bone marrow abnormalities in the lower limbs of patients with cystic fibrosis by means of MR imaging. Eight patients with cystic fibrosis ranging in age from 16 to 35 years (average age 25.1 years) were evaluated with MR imaging of the lower extremities. T1 weighted spin echo sequences were obtained in all patients. Pelvis, femora and tibia were imaged in the coronal plane whereas the feet were imaged in the sagittal plane. The studies were independently evaluated by two musculoskeletal radiologists. The images were not mixed with disease-free images, but the readers were completely unaware of clinical data. Distribution of haematopoietic and fatty marrow was graded on a 5-point scale. In five patients, both observers considered marrow distribution as probably or definitely abnormal relative to their age. Although our findings are very preliminary, our investigation suggests that cystic fibrosis may be added to the list of disorders in which bone marrow abnormalities may be observed.

Adult↗
PubMedDate not supplied

Imaging of semimembranosus bursitis: MR findings in three patients and anatomical study.

We report on three patients with posteromedial knee pain related to semimembranosus bursitis. The semimembranosus bursa has a typical location and morphology around the central tendon of the semimembranosus muscle. These characteristics are demonstrated in patients and by dissection of the tendon and bursa in an embalmed knee specimen.

Adult↗
PubMedDate not supplied

MR imaging of the postoperative ankle.

Although MRI of the ankle has become a routine diagnostic method to cope with pathologic conditions of the ankle, the literature on postoperative evaluation of the ankle by imaging is very scarce. In this short course, the basic principles on surgical reconstruction techniques of ankle ligaments and tendons will be reviewed. The value of imaging--with emphasis on MRI--in depicting postoperative complications will be discussed as well.

Ankle Injuries↗
PubMedDate not supplied

Optimization of sequence parameters in fast MR imaging of the brain with FLASH.

Owing to the intrinsically complex behavior of the signal intensity of fast gradient-refocusing MR sequences, agreement as to the clinically most useful sequence parameters has not yet been reached. This study evaluates the FLASH (fast low-angle shot) sequence for gray-white matter differentiation on normal volunteers at 1.5 T. The FLASH gradient-echo sequence is essentially T1-dependent. For very fast imaging and T1 weighting, the following parameters yield the best results: a flip angle of 30-50 degrees with TR = 20 and TE = 10. To replace T1-weighted SE by the faster FLASH sequence, the best results are achieved by a flip angle of 70-120 degrees with TR = 150-300 and TE = 10 (or shorter, if possible). The most valuable proton-density aspect is achieved by a flip angle of 30 degrees with TR = 300 and TE = 16.

Brain↗