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Biomedical subjects

F E Lecouvet

Publications and source records attributed to F E Lecouvet.

At least 19 recordsLinked to original sources
PubMed2003

MR appearance of cartilage defects of the knee: preliminary results of a spiral CT arthrography-guided analysis.

The aim of this study was to determine signal intensity patterns of cartilage defects at MR imaging. The MR imaging (3-mm-thick fat-suppressed intermediate-weighted fast spin-echo images) was obtained in 31 knees (21 male and 10 female patients; mean age 45.5 years) blindly selected from a series of 252 consecutive knees investigated by dual-detector spiral CT arthrography. Two radiologists determined in consensus the MR signal intensity of the cartilage areas where cartilage defects had been demonstrated on the corresponding reformatted CT arthrographic images. There were 83 cartilage defects at spiral CT arthrography. In 52 (63%) lesion areas, the MR signal intensity was higher than that of adjacent normal cartilage with signal intensity equivalent to (n=31) or lower than (n=21) that of articular fluid. The MR signal intensity was equivalent to that of adjacent normal cartilage in 17 (20%) lesion areas and lower than that of adjacent cartilage in 8 (10%) lesion areas. In 6 (7%) lesion areas, mixed low and high signal intensity was observed. The MR signal intensity of cartilage defects demonstrated on spiral CT arthrographic images varies from low to high on fat-suppressed intermediate-weighted fast spin-echo MR images obtained with our equipment and MR parameters.

Adolescent↗
PubMed2002

Frequency and topography of lesions of the femoro-tibial cartilage at spiral CT arthrography of the knee: a study in patients with normal knee radiographs and without history of trauma.

OBJECTIVE: To determine the frequency and topography of cartilage lesions involving the femoro-tibial joints in patients with normal knee radiographs and without a remembered history of trauma. DESIGN AND PATIENTS: A radiologist retrospectively reviewed the dual-detector spiral CT knee arthrograms performed in 209 consecutive patients (mean age 37.6 years) with normal knee radiographs. Images were analyzed for the presence, grade (Noyes classification system) and location of cartilage lesions, the location being designated by dividing each articular surface into a grid of 16 parts. RESULTS: Fifty-three percent of knees had cartilage lesions of grade 2A or higher that involved articular surfaces to a variable extent: lateral tibial plateau (31%), medial femoral condyle (27%), medial tibial plateau (14%) and lateral femoral condyle (5%). Areas of the posterior half of the lateral tibial plateau and of the inner half of the medial femoral condyle were statistically more frequently involved than their counterparts (P<0.0001). The bare area of the medial tibial plateau, but not that of the lateral tibial plateau, was more frequently involved than the corresponding meniscus-covered area (P<0.0001). CONCLUSION: Cartilage lesions of grade 2A or higher, detected at spiral CT arthrography in 53% of the knees, predominantly involved the posterior half of the lateral tibial plateau, the inner half of the medial femoral condyle and the bare area of the medial tibial plateau.

Adolescent↗
PubMed2002

Spiral CT arthrography of the knee: technique and value in the assessment of internal derangement of the knee.

Computed tomography imaging has achieved excellent multiplanar capability and submillimeter spatial resolution due to the development of the spiral acquisition mode and multidetector row technology. Multidetector spiral CT arthrography (CTA) yields valuable information for the assessment of internal derangement of the joints. This article focuses on the value of spiral CTA of the knee in the assessment of the meniscus, anterior cruciate ligament, and hyaline cartilage lesions. Advantages and disadvantages of spiral CTA with respect to MR imaging are presented.

Adult↗
PubMed2002

Concurrent spinal cord and vertebral bone marrow radionecrosis 8 years after therapeutic irradiation.

Concurrent radionecrosis within the spinal cord and the bone marrow at the same thoracic level was observed 8 years after localized therapeutic irradiation in a patient who had undergone repeated cycles of radiotherapy, glucocorticoid treatment, and chemotherapy for a non-Hodgkin's lymphoma. Mechanisms combining radiotoxic potentialization by glucocorticoids/alkylating agents and delayed radiation-induced vasculitis involving the common arterial pathways to the spinal cord and to the vertebrae were speculated to have acted in a synergistic way.

Adult↗
PubMed2002

Spiral CT arthrography of the postoperative knee.

Computed tomography (CT) has gained multiplanar capability and submillimeter spatial resolution due to the development of spiral acquisition mode and multidetector row technology. Multidetector spiral CT arthrography of the knee is a valuable imaging modality for the assessment of lesions of the meniscus, anterior cruciate ligament (ACL), and articular cartilage. This article presents the value of spiral CT arthrography in the assessment of the postoperative knee with emphasis on the postoperative meniscus, articular cartilage, and ACL graft. This technique may be proposed as an alternative to magnetic resonance arthrography.

Arthrography↗
PubMed2001

Magnetic resonance appearance of uncomplicated Paget's disease of bone.

Paget's disease is a disorder of the bone mesenchyma of the skeleton and is a unique condition in which active bone changes can occur without concomitant significant marrow alteration. When present, marrow changes involve predominantly the paratrabecular and endosteal areas, where bone metabolism is increased. At magnetic resonance (MR) imaging, marrow alterations can become prominent and hence confusing in bones with high trabecular content including vertebrae and pelvis. This article addresses the MR appearance of uncomplicated Paget's disease, including normal pagetic bone, predominantly lytic or sclerotic pagetic bone, and unusual partial involvement of the vertebral body. We will emphasize the added diagnostic value of the combination of imaging techniques that depict either osseous changes including radiographs, computed tomography, and bone scintigraphy, or marrow changes, including MR imaging, to contribute to a noninvasive presumptive diagnosis of Paget's disease in atypical presentations.

Bone Marrow↗
PubMed2001

Magnetic resonance and computed tomography imaging in multiple myeloma.

This article reviews current knowledge on the various lesion patterns that can be observed at magnetic resonance (MR) imaging and on computed tomography images in patients with plasma cell neoplasms. It reviews limitations in specificity of imaging features and emphasizes difficulties in the recognition of the benign or malignant origin of vertebral fractures in these patients. The prognostic significance of MR imaging findings with respect to the natural history of the disease or to survival after treatment is discussed.

Bone Marrow↗
PubMed2001

Magnetic resonance imaging and differential diagnosis of epiphyseal osteonecrosis.

This article addresses imaging features of epiphyseal osteonecrosis that have been highlighted by the use of magnetic resonance imaging, including better depiction of marrow infarcts, better knowledge of their natural history, and better understanding of the different patterns of epiphyseal osteonecrosis. Imaging features that enable differentiation between irreversible lesions, including epiphyseal osteonecrosis and rapidly progressive osteoarthritis, and spontaneously transient lesions, including transient osteoporosis and epiphyseal fractures, are emphasized.

Bone Marrow↗
PubMed2001

Bone marrow transplantation in patients with multiple myeloma: prognostic significance of MR imaging.

OBJECTIVE: This study in myeloma patients treated with myeloablative therapy and bone marrow transplantation assessed the prognostic value of MR imaging before and after treatment of the bone marrow and the prognostic value of an index reflecting changes on MR images obtained before and after treatment. SUBJECTS AND METHODS: MR images (T1-weighted images before and after injection of gadolinium and T2(*)-weighted images) of the spine and pelvis were obtained 1 month before and 1 month after marrow transplantation in 25 consecutive patients with stage III myeloma. Pre- and posttreatment MR imaging patterns of marrow involvement (normal, focal, diffuse), number of focal lesions, and a "marrow evolution index" (0-8 on the basis of comparison of the lesions [number, size, contrast enhancement] and of the surrounding marrow background on pre- and posttreatment MR images) were determined. Hematologic and MR imaging parameters were correlated with the quality of response to treatment (complete versus partial remission) and with relapse-free and overall survival. RESULTS: Response quality did not differ among categories of patients determined on the basis of MR images. Individual MR imaging parameters did not correlate with response duration and survival. Patients with a low marrow evolution index had significantly longer relapse-free (p < 10(-3)) and overall survival (p = 0.005) than patients with a high index. CONCLUSION: Individual MR imaging parameters before and after treatment had no prognostic significance in our series of myeloma patients treated with marrow transplantation. Comparison of MR images before and after treatment using a marrow evolution index may help predict response duration and survival.

Adult↗
PubMed2001

Lesions of the menisci of the knee: value of MR imaging criteria for recognition of unstable lesions.

OBJECTIVE: This study aimed to determine the value of four MR imaging criteria for evaluating unstable meniscal lesions. MATERIALS AND METHODS: Criteria for unstable meniscal lesions were the presence of a displaced meniscal fragment, visibility on more than three 3-mm-thick coronal and two 4-mm-thick sagittal images, having more than one orientation plane or more than one pattern (contour irregularity, peripheral separation, tear), and having intrameniscal high signal intensity on T2-weighted spin-echo images. Sensitivity, specificity, and positive and negative predictive values for recognition of instability among all meniscal lesions were determined for the presence of each individual criterion and for the presence of at least one criterion in 50 consecutive patients (mean age, 46 years) who underwent MR imaging and subsequent arthroscopy. RESULTS: Sensitivities and specificities of these four criteria ranged between 18% and 54% and between 94% and 100%, respectively. Positive and negative predictive values ranged between 92% and 100% and between 39% and 52%, respectively. The presence of at least one criterion enabled recognition of unstable lesions with a sensitivity and specificity of 82% and with positive and negative predictive values of 90% and 70%, respectively. CONCLUSION: The four MR imaging criteria have high specificities and positive predictive values and low sensitivities and negative predictive values when evaluating unstable meniscal lesions.

Arthroscopy↗
PubMed2001

[Hip imaging: what is the best modality?].

Conventional radiography plays a key-role in the assessment of symptomatic hips. A well-performed radiographic examination (comparative A-P views with straight or ascending X-Ray beam, off-lateral view of Lequesne) enables to recognise most bone (fractures, transient osteoporosis, epiphyseal osteonecrosis) and articular lesions (osteoarthritis). In some situations (incoherent radio-clinical findings, need of a confident diagnosis), joint aspiration or additional imaging procedures are needed. Serial radiographs are obtained when no specific treatment can be immediately offered. Bone scintigraphy is obtained to confidently exclude bone or articular disorders or in case of suspected disseminated bone disease. The majority of bone, articular and abarticular lesions can be diagnosed by using MRI. It should be obtained when results are likely to influence the final outcome of the disease.

Algorithms↗
PubMed2001

[Normal bone marrow: dynamic aspects in magnetic resonance imaging].

The bone marrow is a complex organ that contains fat and nonfat cells, the proportion of which varies greatly with age and in the different bones of the skeleton. Magnetic resonance 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. The wide spectrum of appearances of the normal bone marrow at MR imaging will be reviewed. The purpose of this paper is to determine the MR appearance of the bone marrow, to illustrate the phenomenon of marrow conversion and to familiarize the readers with the complex parameters that interfere with the MR appearance of normal bone marrow.

Adipose Tissue↗
PubMed2001

Knee imaging after anterior cruciate ligament reconstruction.

An increasing number of reconstructions of the anterior cruciate ligament (ACL) are performed every year, due to both the increasing occurrence of sport related injuries and the development of diagnostic and surgical techniques. The most used surgical procedure for the torn ACL reconstruction is the use of autogenous material, most often the patellar and semitendinosus tendons. Magnetic resonance (MR) imaging and spiral-CT performed after arthrography with multiplanar reconstructions are the imaging methods of choice for post-operative evaluation of ACL ligamentoplasty. This paper provides a brief bibliographic and more extensive pictorial review of the normal evolution and possible complications after ACL repair.

Anterior Cruciate Ligament↗
PubMed2000

High signal in cerebrospinal fluid mimicking subarachnoid haemorrhage on FLAIR following acute stroke and intravenous contrast medium.

We describe five cases of high signal in the cerebrospinal fluid (CSF) on fast-FLAIR images 24-48 h after onset of stroke. All the patients had undergone perfusion-weighted MRI within 6 h of the onset of the symptoms. The CSF was far brighter than the cortical gyri. The high signal was diffusely around both cerebral hemispheres in two cases and around one hemisphere in two others; it was focal, around the acute ischaemic lesion, in one. CT was normal in all cases. The CSF high signal was transient, decreasing in extent and intensity with time and resolving completely within 3-6 days. It was not associated with worsening of the clinical state or poor outcome. Our explanation of this phenomena is hypothetical: we speculate that it could be due to disruption of the blood-brain barrier resulting in leakage of protein, gadolinium chelates, or both in to the subarachnoid space. It should not be confused with subarachnoid haemorrhage.

Aged↗