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Biomedical subjects

J D Laredo

Publications and source records attributed to J D Laredo.

At least 55 records · Page 3Linked to original sources
PubMed1997

-The diagnosis of localized osteolysis-.

The diagnosis of localized osteolysis (synonym: bone cyst, defect) must be analytical. The site, size, and shape of the defect, its limits, assessed according to the Lodwick classification, reflect the activity of the lesion, the type of any periosteal reaction and the presence of a soft tissue mass are analysed successively. Based on these criteria and the clinical and laboratory characteristics, the image can be classified as quiescent or active, allowing guidance of management.

Bone Cysts↗
PubMed1997

-Infarction or chondroma?-.

The discovery of an image of central bone calcification raises the differential diagnosis of bone infarction and chondroma. The matrix of chondroma is characteristic of cartilage. It produces typical cartilaginous calcifications: rings, arcs, coarse, irregular grains, moth-eaten appearance. These calcifications are predominantly observed in the centre of the image. They are situated in a bone defect, often multilocular, sometimes accompanied by multiple scratch marks of the cortical endosteum. In contrast, infarction is characterized by the presence of a serpiginous calcified border at the interface between live bone and dead bone. In the centre, the bony trabeculae are still visible on CT sections, in contrast with chondroma. On MRI, chondromas present a heterogeneous lobular appearance on T2-weighted sequences (checkerboard appearance) due to alternating zones of high signal intensity cartilaginous matrix and low signal intensity calcified or ossified fibrous septa. On MRI, bone infarction is characterized by a continuous peripheral line with a marked low signal intensity.

Bone Neoplasms↗
PubMed1997

[Diagnosis of calcified deposits in soft tissues].

Calcific deposit within soft tissues is frequently a clue for diagnosis. The radiological analysis of a calcific deposit within soft tissues includes the following aspects: the basic structure of the calcification, the grade of differentiation of the calcification, the site of the calcification, the number of calcific deposits, the shape of the calcification, the changes in the adjacent non-calcified soft tissues and in the adjacent bone, the course of the clinical signs, the course of the radiological abnormalities.

Calcinosis↗
PubMed1997

[Secret information provided by lumbosacral myelography].

The authors emphasize the misleading images of lumbar myelography encountered in common vertebral diseases: disk disease, posterior interapophyseal joint diseases, degenerative and narrow spinal canal, in which dynamic views in the upright position represent the most original contribution of lumbosacral myelography as compared to new techniques. The authors also describe the postoperative appearances observed on lumbosacral myelography and some rarer diseases which must not be missed, such as epidural arachnoid cysts and epidural lipomatosis.

Angiography↗
PubMed1996

Acute vertebral collapse due to osteoporosis or malignancy: appearance on unenhanced and gadolinium-enhanced MR images.

PURPOSE: To distinguish malignant from osteoporotic acute vertebral collapses. MATERIALS AND METHODS: Sixty-three osteoporotic and 30 malignant vertebral collapses were studied in 51 patients (aged 33-88 years) with T1-weighted magnetic resonance (MR) images (n=93), gadolinium-enhanced T1-weighted images (n=72), and T2-weighted images (n=53). RESULTS: Four findings were suggestive of osteoporosis: retropulsion of a bone fragment (10 osteoporotic cases vs 0 malignant cases), preservation of normal signal intensity on T1-weighted images (43 vs four), return to normal signal intensity after gadolinium injection (42 vs four) with horizontal bandlike patterns, and isointense vertebrae on T2-weighted images (28 vs two). Six findings were suggestive of malignancy: convex posterior cortex (21 malignant cases vs four osteoporotic cases), epidural mass (24 vs 0), diffuse low signal intensity within the vertebral body on T1-weighted images (23 vs 12) and in the pedicles (24 vs four), high or inhomogeneous signal intensity after gadolinium injection (17 vs 0) and on T2-weighted images (17 vs 0). CONCLUSION: Gadolinium-enhanced and unenhanced MR images are useful in the differentiation of vertebral collapses.

Acute Disease↗
PubMed1996

Magnetic resonance imaging of the spine in plasma cell dyscrasias. A review.

This review of recent data on the techniques and results of spinal magnetic resonance imaging in plasma cell dyscrasias provides a basis for selecting those patients who are most likely to benefit from this investigation. Sagittal images should be obtained using T1-weighted spin-echo and T2-weighted gradient-echo sequences. Epiduritis is best detected on sagittal or axial images acquired after gadolinium injection using T1-weighted spin-echo or phase-opposed gradient-echo sequences. Among patients with symptomatic multiple myeloma, 80% have abnormal magnetic resonance images of the lower spine due to plasma cell infiltration and this proportion increases with the stage in the Durie and Salmon staging system. Bone marrow signal abnormalities can be focal, diffuse and homogeneous, or diffuse and variegated. Vertebral fractures due to spinal infiltration or osteoporosis are seen in 48% of cases and spinal canal narrowing with impingement of bone tumors or epiduritis on nervous structures in 20%. The response to chemotherapy as evaluated based on conventional criteria is fairly well correlated with changes in magnetic resonance imaging findings. Among asymptomatic multiple myeloma patients with normal roentgenograms, 50% have tumor-related abnormalities on magnetic resonance images of the lower spine, which are associated with an increased likelihood of rapid progression to symptomatic disease. Similarly, one third of patients with an apparently solitary plasmacytoma of bone have evidence of other plasma cell tumors on magnetic resonance images of the lower spine, and this finding is associated with persistence of monoclonal component production after irradiation therapy, which may be of adverse prognostic significance. Patients with monoclonal gammopathies of uncertain significance have no evidence of tumorous lesions on magnetic resonance images of the lower spine.

Bone Marrow↗
PubMed1995

Dialysis arthropathy: outcome after renal transplantation.

PURPOSE: Patients treated by long-term maintenance hemodialysis frequently develop a form of chronic arthropathy that is strongly associated with beta 2-microglobulin amyloid deposition and related, at least in part, to beta 2-microglobulin retention. Successful renal transplantation is followed by a rapid fall in serum beta 2-microglobulin levels and might allow dissolution of amyloid deposits. The purpose of this work was to investigate the effects of renal transplantation on dialysis arthropathy. PATIENTS AND METHODS: Fourteen renal transplant recipients were selected on the basis of previous hemodialysis treatment for at least 10 years (mean 16) and a history of chronic joint pain prior to transplantation. They all received 10 to 17.5 mg/d of prednisone. Posttransplant rheumatologic manifestations were studied prospectively and compared to pretransplant rheumatologic manifestations recorded in medical charts and reported during patient interviews. Pretransplant and posttransplant articular roentgenograms were separately analyzed by three observers who were blinded to timing of the films. Beta 2-microglobulin amyloid was identified by Congo red staining and immunohistology. RESULTS: After a mean posttransplant interval of 54 months (range 12 to 121), the articular condition was improved in 10 patients, unchanged in 1, and worsened in 3, according to patients' assessments. The number of painful joints decreased significantly (P < 0.05) as compared to the pretransplant period. However, the number and size of subchondral bone erosions remained unchanged, destructive arthropathies generally worsened, and articular beta 2-microglobulin amyloid deposits were identified in 2 patients, 2 and 10 years after renal transplantation, respectively. CONCLUSION: Renal transplantation appeared to arrest progression of beta 2-microglobulin amyloid in dialysis patients, but it neither led to dissolution of deposits nor prevented progression of destructive arthropathies. Most articular symptoms were improved, probably as a result of corticosteroid therapy.

Adult↗
PubMed1995

Acute vertebral collapse: CT findings in benign and malignant nontraumatic cases.

PURPOSE: The value of computed tomography (CT) for differentiating benign from malignant causes of nontraumatic acute vertebral collapse (AVC) (associated with pain of less than 3 months duration) was evaluated. MATERIALS AND METHODS: The CT findings of 34 benign (osteoporotic) and 32 malignant (metastatic or myelomatous) nontraumatic AVCs were compared. RESULTS: The following CT findings were significantly more frequent in benign AVCs: cortical fractures of the vertebral body without cortical bone destruction, retropulsion of a bone fragment of the posterior cortex of the vertebral body into the spinal canal, fracture lines within the cancellous bone of the vertebral body, an intravertebral vacuum phenomenon, and a thin diffuse paraspinal soft-tissue mass (PSTM). The following CT findings were significantly more frequent in malignant AVCs: destruction of the anterolateral or posterior cortical bone of the vertebral body, destruction of the cancellous bone of the vertebral body, destruction of a vertebral pedicle, a focal PSTM, and an epidural mass. CONCLUSION: CT can help distinguish benign from malignant causes of nontraumatic AVC.

Adult↗
PubMed1995

[Imaging of the lumbar spine after diskectomy].

The radiological investigation of persistent or recurrent sciatica after lumbar diskectomy essentially consists of demonstrating recurrent disk herniation. Comparison between plain and contrast enhanced CT or MR examinations at the level of the diskectomy is the main step of the radiological survey. The meanings of the various radiological findings are discussed. Other lesions that may induce persistent sciatica after lumbar diskectomy include degenerative narrowing of the lateral recess, spinal instability, stress fracture of the remaining neural arch, pseudo-meningomyelocele after laminectomy.

Diskectomy↗
PubMed1995

[Vertebral vacuum phenomena].

The spinal vacuum phenomenon is a collection of gas within the disk space, the vertebral body, the apophyseal joint or the spinal canal. The intradiscal vacuum phenomenon is frequently observed in degenerative disk disease and crystal-induced diskopathy. This has obvious significance to the radiologist, who, on observing a narrowed disk space or collapsed vertebral body, might otherwise consider infectious or neoplastic spondylitis, a likely possibility. The presence of vacuum phenomenon militates against the diagnosis of infection or tumor.

Chondrocalcinosis↗
PubMed1995

[Degenerative vertebral dislocation].

Degenerative vertebral dislocations (laterolisthesis) are responsible for progressive transverse intervertebral shift. These changes appear like a translation of the lateral edge of a vertebra compared to that of the underlying vertebra and are easily diagnosed. Vertebral dislocations can be secondary to active lumbar scoliosis or unilateral or asymmetrical degenerative spondylolisthesis. In every case, the appearance of laterolisthesis is reflected by the onset or aggravation of scoliosis which may become self-perpetuating. This lesion is secondary to osteoarthritic disruption of the integrity of the intervertebral disk and ligaments. Open and closed patterns have been described depending on the side of the associated disk opening. The onset of a rotatory dislocation reflects the progressive evolution of the deformity, which may require medical treatment, or surgical reduction and fixation by vertebral arthrodesis.

Humans↗
PubMed1995

[Fibrous dysplasia of bone and osteofibrous dysplasia. Focusing].

This is a review article on fibrous dysplasia of bone. All aspects of this condition including, macroscopic and histologic findings, lesion distribution, clinical, radiological and biological findings as well as evolution and treatment are discussed. A classification of skeletal lesions based on then appearance on plains films and computed tomography is proposed; 3 radiological types are differentiated: non-expanding bone lesions, expanding lesions with a thick periosteal reaction and expanding lesions with a thin periosteal shell. Main features of osteofibrous dysplasia are also discussed.

Bone Neoplasms↗
PubMed1994

[Value of magnetic resonance imaging in myeloma].

Magnetic resonance imagery (MRI) of the spinal cord has become a standard method and its diagnostic and prognostic power in multiple myeloma has been widely demonstrated. Before treatment, MRI reveals two basic types of abnormalities yielding focal and diffuse signals. Focal lesions are seen as localized hyposignals on spin echo T1 sequences (SET1) and are enhanced by injection of gadolinium and changed to hypersignals in T2 weighted sequences. These images identify nodular tumoural masses. Diffuse lesions are seen most often as homogeneous SET1 images with an intensity similar to the vertebral body. This type of image is not specific of tumoural infiltration and can be benign in nature. The second type of diffuse signal is often called a "salt and pepper" image due to the juxtaposition of multiple hyposignals (suspected tumoural tissue) and hypersignals (fat tissue). We have observed this type of image in 27% of our series of multiple myelomas. The capacity of MRI to detect myelomas located in bone tissue is much greater than conventional radiography of the spine and is particularly sensitive to expansive tumoural lesions threatening the cord. MRI should always be performed as part of the initial work-up even in the absence of clinical signs. There is a good correlation between MRI of focal tumours and the biological response to treatment, although other biological markers may be more precise and easier to obtain. MRI can also be used to differentiate between benign monoclonal gammapathy and multiple myeloma, particularly in cases where there is a disagreement between the clinical and laboratory data. We have also studied MRI in solitary plasmacytomas of the spine.

Diagnosis, Differential↗
PubMed1994

Paradiaphyseal calcific tendinitis with cortical bone erosion.

OBJECTIVE: To determine the clinical, radiologic, and histologic features of calcific tendinitis with cortical bone erosion. METHODS: The records of 6 patients with paradiaphyseal calcific tendinitis and adjacent bone cortex erosion were reviewed. RESULTS: Calcific tendinitis involved the linea aspera in 4 patients, the bicipital groove in 1 patient, and the deltoid insertion in another. Calcium deposits were associated with cortical bone erosions, revealed on plain radiographs in 4 patients and computed tomography scans in 2. Bone scans were performed in 2 patients and showed local hyperfixation of the isotope. In 4 patients, suspicion of a neoplasm led to a biopsy. Calcium deposits appeared to be surrounded by a foreign body reaction with numerous giant cells. Apatite crystals were identified by transmission electron microscopy and elemental analysis in 1 surgical sample. CONCLUSION: Paradiaphyseal calcific tendinitis with cortical bone erosion is an uncommon presentation of apatite deposition disease.

Adult↗