Biomedical subjects

B Maldague

Publications and source records attributed to B Maldague.

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↗

PubMed2003

[Cardiac imaging by means of four-detector row computed tomography and cardiac gating].

Electrocardiographically-assisted imaging is a recent development in multislice spiral computed tomography. In this article, we summarize the principles of four-detector row CT for cardiac applications. Following is an overview of the potential of this technique to evaluate the heart, the thoracic aorta, and the paracardiac pulmonary parenchyma. Technical considerations for optimal imaging are highlighted.

Aorta, Thoracic↗

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

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↗

PubMed2002

[Atypical ganglion cysts].

Intra- or para-articular ganglion cysts are frequent and can develop at some distance from the joints. The authors describe examples of typical and atypical ganglion cysts, namely meniscal cyst, intra-articular cyst, intraosseous cyst, intraneural cyst of tibial nerve, adventitial cyst of popliteal artery, and para-articular cyst of the hip, filled with gas of presumed articular origin. The diagnosis of a ganglion cyst can be difficult when there is no evident articular communication. If demonstration of communication is necessary (in case of uncertain diagnosis or for preoperative assessment), the best procedure is arthrography followed by a CT scan 1-2 hours after the injection.

Diagnosis, Differential↗

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 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

Costal cartilage fractures as revealed on CT and sonography.

OBJECTIVE: We describe the CT and sonographic appearance of 15 costal cartilage fractures observed in eight patients. CONCLUSION: On CT, fracture was seen as a low-density area through the costal cartilage, with surrounding calcifications present near old fractures, and gas density within the cleft in some cases. On sonography, cartilage fracture appeared as an interruption of the smooth anterior aspect of the cartilage.

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

[Myositis ossificans and other ossifying lesions of the soft tissues].

Knowledge of the clinical history and typical imaging characteristics of myositis ossificans is important as identification of this entity will avoid unnecessary and invasive work-up. Conversely, the radiologist must pay attention to any atypical clinical or imaging finding, which will warrant further investigations.

Diagnosis, Differential↗

PubMed2000

The lumbar vertebral body and diskovertebral junction. Radio MR imaging anatomic correlations.

Radiographs and MR images of spine specimens provide superb tomographic views of changes that involve the mineralized network and the medullary content of vertebral bodies. By illustrating changes in the balance between bone resorption and formation and between fat and nonfat marrow cells, these frozen images of the reality help us to understand normal variants and lesions that develop in osseous and articular diseases of the lumbar spine.

Bone Marrow↗

PubMed2000

Dual-detector spiral CT arthrography of the knee: accuracy for detection of meniscal abnormalities and unstable meniscal tears.

PURPOSE: To determine the sensitivity and specificity of dual-detector spiral computed tomographic (CT) arthrography of the knee in the detection of meniscal abnormalities and unstable meniscal tears. MATERIALS AND METHODS: The meniscal changes in 50 consecutive patients who underwent dual-detector spiral CT of the knee after intraarticular injection of iodinated contrast material (0.55-mm effective section thickness, 0.75 pitch value, 0.3-mm increment reconstruction, 0.43-mm in-plane resolution, 0.3-mm longitudinal resolution) were determined by two observers and were compared with arthroscopic findings. The sensitivity and specificity of CT arthrography for the detection of meniscal abnormalities and unstable meniscal tears and the kappa statistics for assessing interobserver reproducibility were determined. RESULTS: The sensitivity and specificity for the detection of meniscal abnormalities were 98% and 94%, respectively. The sensitivity and specificity for the detection of unstable meniscal tears were 97% and 90%, respectively. Interobserver agreement was excellent for the detection of meniscal abnormalities (kappa = 0.899) and of unstable meniscal tears (kappa = 0.885). CONCLUSION: Dual-detector spiral CT arthrography of the knee is an accurate and reproducible method for detecting meniscal abnormalities and unstable meniscal tears.

Adult↗

PubMed1999

Ferumoxides-enhanced quantitative magnetic resonance imaging of the normal and abnormal bone marrow: preliminary assessment.

The purpose of our study was to assess the effects of intravenous administration of ferumoxides on normal and abnormal vertebral bone marrow T1 and T2 relaxation times. Changes in bulk T1 and T2 relaxation times induced by intravenous administration of ferumoxides were determined in the normal vertebral marrow of two healthy subjects and four patients. In the four patients, changes in bulk T1 and T2 values induced by furomoxides injection were also determined in 12 vertebral metastases. Relative to precontrast relaxation time values, bulk T1 and T2 values of normal bone marrow had declined by a mean of 24% and 19%, respectively, in the two subjects and the four patients 45 minutes after ferumoxides administration. Relative to precontrast values, bulk T1 and T2 values of abnormal bone marrow had decreased by a mean of 16% and 2%, respectively. Decreases in bulk T1 and T2 values in normal bone marrow and in bulk T1 values in metastases were statistically significant (P<0.001). Changes in bulk T2 values observed in metastases were not statistically significant. Quantitative MRI demonstrates that ferumoxides infusion induces a decrease in bulk T1 and T2 relaxation times of normal bone marrow. It also suggests a lack of T2 shortening in bone metastases.

Adult↗

PubMed1999

Fat conversion of femoral marrow in glucocorticoid-treated patients: a cross-sectional and longitudinal study with magnetic resonance imaging.

OBJECTIVE: To study the changes in hematopoietic marrow in patients given glucocorticoid (steroid) therapy. METHODS: In a cross-sectional study, high-resolution T1-weighted magnetic resonance imaging (MRI) images of the proximal femur were obtained in an unselected series of 29 premenopausal female patients with systemic lupus erythematosus (SLE) and in a series of 29 age-matched healthy female subjects. In a longitudinal analysis, 2 MRI studies were performed 19 months apart in 11 patients with SLE (including 9 patients from the cross-sectional study who were evaluated before treatment) and in 7 patients with rheumatoid arthritis (RA). The percentage of fat marrow and the index of marrow conversion (IMC) were derived from the MRI images to estimate the degree of transformation of hematopoietic into fatty marrow in the area of the femoral neck. Values observed in the cross-sectional study and their changes over time were correlated with treatment data. RESULTS: The cross-sectional study performed in SLE patients indicated that their mean (+/- SD) percentage of fat marrow (48+/-36%) and IMC (82+/-12) were significantly more elevated than those in the healthy control subjects (18+/-16% and 75+/-6, respectively) (P<0.01). The magnitude of fat conversion correlated positively with the mean daily dose of oral prednisolone, and was higher in patients with ischemic bone lesions. The longitudinal study performed in SLE and RA patients revealed that IMC changes over time correlated positively with daily prednisolone intake (r = 0.71; P = 0.001), fat conversion occurring exclusively in patients receiving a mean prednisolone dose < or =7.5 mg/day. CONCLUSION: MRI indicates that fat conversion occurs in the proximal femur of steroid-treated patients. The magnitude of fat conversion correlates with steroid intake and is higher in patients with ischemic bone lesions.

Adolescent↗

PubMed1999

Skeletal survey in advanced multiple myeloma: radiographic versus MR imaging survey.

In an attempt to compare the sensitivity of bone radiographs and bone marrow magnetic resonance (MR) imaging for bone lesion detection in patients with stage III multiple myeloma (MM) and to evaluate the possible consequences of the replacement of the conventional radiographic skeletal survey (RSS) by an MR survey of the spinal and pelvic bone marrow in these patients, we obtained MR studies of the thoracic and lumbar spine, pelvis and proximal femurs in addition to the conventional RSS (including radiographs of the skull, entire spine, pelvis, ribs, humerus and femurs) in 80 consecutive patients with newly diagnosed stage III MM according to the Durie and Salmon staging system (based on blood tests and on the RSS). The performance of MR and radiographic studies to detect bone lesions in given anatomic areas and in given patients were compared. The consequences on MM staging following the substitution of the RSS by the MR survey were assessed. MR imaging was superior to radiographs for lesion detection in the spine (76% v 42% of patients) and pelvis (75% v 46% of patients). The RSS was superior to the limited MR imaging survey for the detection of bone involvement in the patient population (87.5% v 79% of patients). If the RSS had been replaced by the MR imaging survey for patient staging, 7/80 patients would have been categorized as stage I and one as stage II MM on the basis of normal MR findings and biological findings consistent with these stages. Substitution of the RSS by a limited spinal and pelvic marrow MR survey would lead to 'understaging' of 10% of patients with otherwise stage III MM on the basis of blood tests and the conventional RSS.

Adult↗