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Biomedical subjects

L Sarazin

Publications and source records attributed to L Sarazin.

16 recordsLinked to original sources
PubMed1999

Study of the joint space of the hip on supine and weight-bearing digital radiographs.

AIM: To compare hip joint space on supine and weight-bearing anteroposterior digital radiographs. MATERIALS AND METHODS: Fifty anteroposterior views of the hip in 25 patients were taken in supine and weight-bearing positions on a fluoroscopic unit. Two observers in a double-blind study assessed the width of the joint space on an Easy Vision unit with an indirect method of measurement (metric index). RESULTS: Inter-observer and intra-observer variabilities of the metric index were less than 4.1%. There was no significant difference of the metric index of the hip (P>0.05), between supine and weight-bearing positions. CONCLUSION: There is no significant difference of the width of the joint space of the hip between supine and weight-bearing anteroposterior radiographs. Measuring joint space loss in osteoarthritis of the hip with anteroposterior views should be done with radiographs of the hip in the supine position to improve image quality.

Adult↗
PubMed1998

Longitudinal stress fractures of the tibia: comparative study of CT and MR imaging.

The aim of this study was to compare the performance of CT and MRI in the diagnosis of longitudinal stress fracture of the tibia (LSFT). A retrospective study of imaging findings was performed in 15 patients with LSFT. The CT and MR images were compared for detection of fracture line, callus, bone marrow edema, and soft tissues changes. The CT and MRI techniques allowed the detection of the fracture line in 82 and 73 % of cases, respectively. The callus was always visualized with CT or MRI. The MRI technique had a markedly higher sensitivity than CT in the detection of bone marrow edema (73 vs 18 %) and soft tissue lesions (87 vs 9 %). This may cause a misleading aggressive appearance on MRI. Computed tomography remains the best imaging modality for diagnosis of LSFT. However, MRI findings should be known to obviate the performance of CT or bone biopsy.

Adolescent↗
PubMed1998

[MRI and articular cartilage].

Although plain films are fundamental for routine imaging of degenerative chondral lesions, MRI is a promising tool of investigation for the articular cartilage. Its modalities are still imprecise and debated, but, because of its noninvasiveness, it is destined to be preferred over arthroCT. The small size of the cartilage requires thin slices of less than 3-mm thick. The various features of normal cartilage images must be well known. They depend on acquisition parameters, zonal structure of the cartilage and numerous artifacts (partial volume average, chemical shift, magnetic susceptibility, truncation, "magic angle"). Fast SE images provide a good compromise between contrast and the signal-to-noise ratio. T2-weighted images take advantage of an arthrographic effect in case of joint effusion. 3D GE images allow a more accurate evaluation with 1-mm thick slices. In all sequences, adding of a fat-suppression presaturation increases contrast between the cartilage and the surrounding structures. The diagnostic accuracies of the different sequences and of MR arthrography are discussed. Quantitative measurements of cartilage thickness and volume remain the topic of clinical research.

Arthrography↗
PubMed1997

[Imaging].

The panoply of imaging techniques useful in podology is essentially limited to X-rays. Standard "standing" and "lying" X-rays furnish most of the required information. Arthrography is sometimes performed, in particular for trauma or tumour of the ankle. CT scan and MRI make a decisive contribution in difficult cases, notably in fractures and in small fractures without displacement. The two latter techniques are useful in tendon, ligament and muscular disorders, where echography is also informative. Rigorous analysis of radiographies and a good knowledge of foot disorders make these imaging techniques efficacious.

Adult↗
PubMed1996

Correlative imaging and pattern approach in ultrasonography of bone lesions: a pictorial essay.

The purpose of this paper is to sensitize musculoskeletal and general sonographers to a wide variety of bony abnormalities that may be noted adjacent to soft tissues of interest. The authors gathered sonographic images displaying abnormalities involving the periosseous, periosteal and cortical tissues from numerous patients who underwent imaging in their department. When available, correlative imaging or the pathological diagnosis (or both) is provided. The authors conclude that musculoskeletal ultrasonography, when used to its full potential, can reveal corroborative and occasionally unsuspected evidence of underlying bony abnormalities, so that correlative imaging (e.g., plain radiography, computed tomography, magnetic resonance imaging or bone scanning) can be performed as appropriate.

Bone Diseases↗
PubMed1995

Soft-tissue recurrence of osteosarcoma: ultrasound findings.

The authors describe a 26-year-old woman with soft-tissue recurrence of osteosarcoma, which presented as focal soft-tissue swelling after limb salvage surgery and insertion of a metallic endoprosthesis. Because of the clinical presentation, ultrasonography was performed. The characteristic ultrasonographic pattern of soft-tissue tumours is summarized here, and the role and limitations of ultrasonography in this situation are discussed.

Adult↗
PubMed1995

Magnetic resonance imaging of lateral ventricular tumours.

The authors review their experience with magnetic resonance imaging (MRI) of giant lateral ventricular tumours, placing special emphasis on the imaging features that aid in the differential diagnosis. The tumours illustrated include astrocytoma, oligodendroglioma, neurocytoma, subependymoma, metastatic lesions and subependymal giant cell astrocytoma. Because of their large size, most of these lesions cause hydrocephalus. The presence of associated edema indicates direct brain invasion or a higher grade of tumour differentiation. The degree and pattern of contrast enhancement, as well as the signal characteristics before administration of contrast agent, are nonspecific. The location of the tumour within the lateral ventricles and the patient's age are the most helpful diagnostic clues. Giant lateral ventricular tumours are uncommon, and the patients usually come to clinical attention with symptoms related to increased intracranial pressure. MRI assists in surgical planning by defining the exact location of the lesion and its relation to adjacent structures. Although the signal characteristics and patterns of contrast enhancement are nonspecific, preoperative diagnosis is possible in most cases if the imaging findings are correlated with the patient's age and the specific location of the tumour within the lateral ventricles.

Adolescent↗
PubMed1993

[Computerized evaluation of tumor volume with MRI. Applications to the surveillance of acoustic neurinoma].

Routine volume measurement techniques most often produce a rough approximate with poor accuracy for smaller structures. The results are generally improved by increasing the examination time, so that the technique then becomes unusable in daily practice. We propose a semiautomated volume calculation method with MRI, and its application to the surveillance of non-operated acoustic neuromas. This calculation technique, based on a threshold-setting method, allows accurately delineating the contours of the structures to be measured on each section and quickly calculating the total volume. After testing its reliability on control volumes, this techniques has been used to assess the evolutive nature of 16 acoustic neuromas with mild symptoms in 15 patients rejected for surgery. The radiological examinations were 428 days apart in average. On the basis of the obtained results, a theoretic tumor doubling time was calculated, thus allowing comparison between all patients. All controlled neuromas had a theoretic doubling time ranging from 427 to 4,884 days, corresponding to little- or non-evolutive lesions, which may be explained by the series selection bias excluding evolutive tumors referred to surgery. Owing to its rapidity and easy use, this semiautomated volume calculation technique for MRI seems to be very interesting as it allows reliably quantifying a volume variation that is usually estimated approximately.

Adult↗
PubMedDate not supplied

Herpes zoster vasculitis: demonstration by MR angiography.

A patient presented with multiple cerebral infarcts in various vascular territories after having been treated for herpes zoster ophthalmicus. Magnetic resonance angiography demonstrated multiple focal stenoses involving the proximal intracranial vessels which corresponded to endarteritis at autopsy.

Aged↗
PubMedDate not supplied

Lumbar facet joint arthrography with the posterior approach.

Lumbar facet joint (LFJ) arthrography with intraarticular injections of long-acting steroids and local anesthetics is routinely used for therapeutic purposes in selected patients for relief of low back pain. The procedure may also be used for diagnostic reasons to establish the source of such pain. However, because direct access to the LFJ space is not always possible owing to degenerative changes such as osteophytes, another posterior approach has been proposed for LFJ arthrography. With the patient in the prone position, a spinal needle is inserted vertically into the inferior recess of an LFJ with fluoroscopic guidance and the patient under local anesthesia. To facilitate puncture, cushions are placed under the patient's abdomen to flatten normal lumbar lordosis, which enlarges the inferior recess of the LFJ. Use of cushions also results in a decrease in tissue thickness in the patient, thereby improving image quality and decreasing radiation exposure. LFJ arthrography can demonstrate the causative role of facet disease in abnormalities responsible for low back pain or sciatica and can be performed easily and rapidly with this direct posterior approach.

Anesthetics, Local↗
PubMedDate not supplied

[Spiral X-ray computed tomography: a new modality of scanner imaging].

Spiral computed tomography is a new imaging modality that presents several advantages when compared to conventional and dynamic computed tomography. It consists in a continuous rotation of the X-Ray tube around the anatomical area to be explored, simultaneously with a move of the examination table at a constant speed. Advantages are the short acquisition time (below one minute), optimization of the intravenous injection of the iodinated contrast material, acquisition of a gapless volume of data which can be post-processed, permitting axial reconstructed sections which are perfectly contiguous, as well as an easy access to 2D multiplanar and 3D reconstructions, with the benefit of a substantial decrease in patients' radiation. This paper will review the prominent advantages, as well as the current limitations, of this new imaging modality.

Humans↗
PubMedDate not supplied

Tophaceous gout of the lumbar spine mimicking an epidural abscess: MR features.

We present the MR findings in a case of tophaceous gout of the lumbar spine with cauda equina compression, mimicking an epidural abscess. The diagnosis was clinically unsuspected and confirmed at laminectomy. Tophus material in the paraspinal soft tissues appeared intermediate in signal intensity and showed heterogeneous contrast enhancement.

Abscess↗