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Y Miaux

Publications and source records attributed to Y Miaux.

At least 19 recordsLinked to original sources
PubMed2005

The dural tail sign--beyond meningioma.

There have been somewhat conflicting reports published about the significance of linear meningeal thickening and enhancement adjacent to peripherally located cranial mass lesions on contrast-enhanced magnetic resonance (MR) images. Most of the authors consider this so-called "dural tail sign" or "flare sign" almost specific for meningioma. This review illustrates the MR imaging findings of a wide spectrum of disorders that show this dural sign. Causes include other extra-axial lesions and also peripherally located intra-axial lesions such as neuromas, chloromas, metastases, lymphoma, gliomas, pituitary diseases, granulomatous disorders, and also cerebral Erdheim-Chester disease. The dural tail sign is not specific to a particular pathological process. Nevertheless, useful conclusions can be drawn from the morphology of the lesion, its enhancement pattern, and its solitary or multifocal presentation. The final diagnosis must be based on cerebrospinal fluid studies or histological studies after biopsy.

Adolescent↗
PubMed2004

Whole-Organ Magnetic Resonance Imaging Score (WORMS) of the knee in osteoarthritis.

OBJECTIVES: To describe a semi-quantitative scoring method for multi-feature, whole-organ evaluation of the knee in osteoarthritis (OA) based on magnetic resonance imaging (MRI) findings. To determine the inter-observer agreement of this scoring method. To examine associations among the features included in the scoring method. METHODS: Nineteen knees of 19 patients with knee OA were imaged with MRI using conventional pulse sequences and a clinical 1.5 T MRI system. Images were independently analyzed by two musculoskeletal radiologists using a whole-organ MRI scoring method (WORMS) that incorporated 14 features: articular cartilage integrity, subarticular bone marrow abnormality, subarticular cysts, subarticular bone attrition, marginal osteophytes, medial and lateral meniscal integrity, anterior and posterior cruciate ligament integrity, medial and lateral collateral ligament integrity, synovitis/effusion, intraarticular loose bodies, and periarticular cysts/bursitis. Intraclass correlation coefficients (ICC) were determined for each feature as a measure of inter-observer agreement. Associations among the scores for different features were expressed as Spearman Rho. RESULTS: All knees showed structural abnormalities with MRI. Cartilage loss and osteophytes were the most prevalent features (98% and 92%, respectively). One of the least common features was ligament abnormality (8%). Inter-observer agreement for WORMS scores was high (most ICC values were >0.80). The individual features showed strong inter-associations. CONCLUSION: The WORMS method described in this report provides multi-feature, whole-organ assessment of the knee in OA using conventional MR images, and shows high inter-observer agreement among trained readers. This method may be useful in epidemiological studies and clinical trials of OA.

Aged↗
PubMed2003

Comparison of fixed-flexion positioning with fluoroscopic semi-flexed positioning for quantifying radiographic joint-space width in the knee: test-retest reproducibility.

OBJECTIVE: To compare fixed-flexion radiography of the knee with fluoroscopic semi-flexed radiography in terms of the reproducibility of measurements of minimum joint-space width (JSW) in the medial femorotibial joint. METHODS: Posteroanterior radiographs of the right knees of 18 normal volunteers were acquired with the patients standing on an upright fluoroscopy table, the feet externally rotated 10 degrees and the toes touching the vertical table. Knees were positioned and radiographed with two different techniques: (1) semi-flexed positioning under fluoroscopic guidance using a horizontal X-ray beam; and (2) fixed-flexion positioning, with the knees and thighs touching the vertical table, using 10 degrees caudal beam angulation without fluoroscopy. Foot maps were drawn in each case. Subjects were repositioned and radiographed twice using each technique. The posteroanterior beam angle that optimally projected the medial tibia plateau with the patient in the fixed-flexion position was also determined for each subject in a separate examination using fluoroscopy. Ten patients with osteoarthritis were also examined with the fixed-flexion technique using a conventional radiographic unit. Minimum medial joint-space width (JSW) in the medial femorotibial joint was measured manually with a graduated lens and also with a semi-automated computer algorithm. RESULTS: Reproducibility errors (root-mean-square SD) for manual and automated JSW measurement were 0.2 mm and 0.1 mm, respectively, for fluoroscopic semi-flexed positioning in volunteers; 0.3 mm and 0.1 mm, respectively, for fixed-flexion positioning in volunteers; and 0.2 mm and 0.1 mm, respectively, for fixed-flexion positioning in osteoarthritic patients. The optimal beam angle for visualizing the joint space was 9.0 degrees +/-3.6 degrees. CONCLUSION: Fixed-flexion, non-fluoroscopic radiography of the knee can provide reproducible JSW measurement using widely available X-ray equipment. This technique is more feasible for multicenter clinical studies and routine clinical use than are methods that rely on fluoroscopic alignment of the tibial plateau.

Adult↗
PubMed2003

Metallic artefacts in MR imaging: effects of main field orientation and strength.

AIM: To determine the effect of metallic implant positioning on magnetic resonance (MR) imaging artefacts, and to determine the optimal imaging parameters for minimization of metallic artefacts. MATERIALS AND METHODS: In a phantom and in three joints with non-ferromagnetic metallic implants imaged at 1.5 and/or at 0.2 T, we examined the influence of the static magnetic field (B(0)) strength and orientation, frequency-encoding direction, and type of imaging sequence on metallic artefacts. RESULTS: The impact of artefacts caused by metallic objects depends mainly on the relationship between the anatomy of interest and the orientation of the object relative to the direction of B(0). The main field strength plays a less important role, but its orientation depends on the type of MR imager. CONCLUSION: MR artefacts can be easily minimized by optimally positioning patients with metallic implants in the magnet. Knowledge of how this influences MR imaging is helpful in patient selection and guiding limb positioning.

Artifacts↗
PubMed1998

Imaging findings of central nervous system neuroepithelial cysts.

Neuroepithelial cysts are rare and mostly asymptomatic cerebrospinal fluid (CSF)-like cysts. We describe herein the imaging findings in five patients with neuroepithelial cysts. Two cases of proven and three of presumed neuroepithelial cysts are presented. Three of five are located in the thalamus, a location which is not characteristic for neuroepithelial cysts. In the case of incidental finding of asymptomatic neuroepithelial cyst, clinical and radiological follow-up is indicated and surgical intervention is not necessarily warranted.

Adult↗
PubMed1998

[Intracranial dural arteriovenous fistula with perimedullary venous drainage].

Two cases of intracranial dural arterio-venous fistula (DAVF) with perimedullary venous drainage are reported. In both cases, MRI T2-weighted (T2W) images showed an hypersignal within the cervical cord with sparing of the thoracic cord. In one case perimedullary vessels were demonstrated on T1W images after gadolinium i.v. administration. A complete spinal angiogram did not show evidence of fistula but demonstrated the lack of opacification of the conus medullaris venous drainage. Cerebral angiogram demonstrated in the first case a foramen magnum DAVF and in the second case a petrous apex DAVF. Hypersignal limited to the cervical cord at MRI on T2W images remain exceptionnal in case of intracranial DAVF with perimedullary venous drainage. When neurological symptoms are suggestive, post gadolinium T1W sequences should be conducted, followed by selective spinal angiogram. If normal venous drainage is not objectivated (e.g. opacification of radiculo-medullary veins on the late phase), cerebral angiogram should be done to rule out an intracranial DAVF.

Aged↗
PubMed1997

High-intensity lesion on T1-weighted MR images in neurofibromatosis type 1: a case of premalignant lesion.

We report a patient with NF1, who was followed up because of an optic glioma and one enhancing lesion presumed to be a pilocytic astrocytoma. T1- and T2-weighted MR images showed also a hyperintense periventricular lesion with no enhancement and no mass effect, of an unsuspected nature. Three years later a glioblastoma multiforme developed at the site of this preceding lesion.

Adult↗
PubMed1997

Cranial MRI findings in myotonic dystrophy.

MRI was performed in 13 patients with the adult form of myotonic dystrophy (MD) and compared with that of sex- and age-matched normal controls. There was some cerebral atrophy in the patients and marked thickening of the skull in three of them, associated with ossification of the falx cerebri in two. We found high-signal areas on T2-weighted images in the white matter in 9 (70%) of the patients; five showed high-signal areas in the subcortical white matter of the temporal lobes. These findings were associated with intellectual impairment in only one patient, who had a history of a difficult birth and temporal lobe epilepsy.

Adult↗
PubMed1997

Contrast enhancement of the facial nerve on MRI: normal or pathological?

We prospectively analysed the normal contrast-enhanced MRI features of the facial nerve and determined criteria for pathological contrast enhancement. We studied 31 patients with clinically normal facial nerves with T1-weighted images before and after contrast medium. The intensity, thickness and right-left symmetry of enhancement were assessed in each segment and correlated with MRI features observed in abnormal facial nerves. Enhancement along at least one segment of the facial nerve was seen in 98% of cases, but only within the facial canal: labyrinthine segment: 78.2%; geniculate ganglion: 96.9%; tympanic: 88.4%; mastoid: 66.6%. Marked (+2) to intense (+3) enhancement was seen in the labyrinthine segment in 17.4%, the geniculate ganglion in 36.3%, and the tympanic (25.6%) and mastoid (7.1%) segments, whereas intense enhancement was only seen in the geniculate ganglion (6%) and the tympanic segment (11.6%). A right-left asymmetry was noted in 69% of cases. No correlation was found between enhancement and the thickness of the nerve. No enhancement of the eighth nerve was seen. We suggest three criteria for pathological enhancement: enhancement outside the facial canal; extension of enhancement to the eighth nerve; and intense enhancement in the labyrinthine and/or mastoid segments.

Adolescent↗
PubMed1997

Dural sinus thrombosis: CT and MR imaging of different stages.

Cerebral dural sinus thrombosis remains an uneasy clinical diagnosis because it may present with a spectrum of nonspecific manifestations. CT and MR findings have been described to help recognize this entity. We report here a case with different stages of thrombosed superior sagittal and right transverse dural sinuses demonstrated by CT and MR imaging.

Adult↗