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Biomedical subjects

A Cotten

Publications and source records attributed to A Cotten.

97 records · Page 6Linked to original sources
PubMedDate not supplied

Extrinsic and intrinsic ligaments of the wrist: normal and pathologic anatomy at MR arthrography with three-compartment enhancement.

The ligaments of the wrist have been demonstrated with magnetic resonance (MR) imaging by many authors. Distinction has been made between the extrinsic, or radiocarpal and ulnocarpal, ligaments and the intrinsic, or intercarpal, ligaments. The stability of the wrist depends on numerous ligaments: The volar ligaments are important stabilizers of the wrist, whereas the dorsal ligaments are less crucial for wrist stability. An MR imaging protocol that demonstrates these structures with high resolution has been developed. Cadaveric wrists are imaged with a spoiled gradient-recalled-echo volume-acquisition technique with fat suppression after three-compartment enhancement with a contrast agent containing gadolinium. The specimens are then sectioned, and the anatomic and pathologic findings are correlated with the findings on the MR images. The extrinsic and intrinsic ligaments of the wrist are clearly demonstrated with this technique. This protocol was designed for anatomic study and promotes understanding of the anatomy and biomechanics of the wrist; it is not intended for clinical use.

Angiography↗
PubMedDate not supplied

Fat suppression in MR imaging: techniques and pitfalls.

Fat suppression is commonly used in magnetic resonance (MR) imaging to suppress the signal from adipose tissue or detect adipose tissue. Fat suppression can be achieved with three methods: fat saturation, inversion-recovery imaging, and opposed-phase imaging. Selection of a fat suppression technique should depend on the purpose of the fat suppression (contrast enhancement vs tissue characterization) and the amount of fat in the tissue being studied. Fat saturation is recommended for suppression of signal from large amounts of fat and reliable acquisition of contrast material-enhanced images. The main drawbacks of this technique are sensitivity to magnetic field nonuniformity, misregistration artifacts, and unreliability when used with low-field-strength magnets. Inversion-recovery imaging allows homogeneous and global fat suppression and can be used with low-field-strength magnets. However, this technique is not specific for fat, and the signal intensity of tissue with a long T1 and tissue with a short T1 may be ambiguous. Opposed-phase imaging is a fast and readily available technique. This method is recommended for demonstration of lesions that contain small amounts of fat. The main drawback of opposed-phase imaging is unreliability in the detection of small tumors embedded in fatty tissue.

Adipose Tissue↗
PubMedDate not supplied

Therapeutic percutaneous injections in the treatment of malignant acetabular osteolyses.

Percutaneous injection of methylmethacrylate or ethanol may provide marked pain relief or bone strengthening in patients with malignant acetabular osteolyses who are unable to tolerate surgery. Injection of methylmethacrylate is usually indicated when osteolysis involves the weight-bearing part of the acetabulum (ie, the acetabular roof); in all other cases, ethanol injection is preferred. Ethanol and methylmethacrylate injections may be performed together if both weight-bearing and nonweight-bearing parts of the acetabulum are involved or extensive soft-tissue involvement is present. Moreover, these injections may be performed prior to radiation therapy, which complements their action due to similar but delayed effects on pain, or after radiation therapy that failed to relieve pain or in cases of local recurrence. Radiography and computed tomography must be performed prior to therapeutic percutaneous injection to assess the location and extent of the lytic process, the presence of cortical destruction or fracture, and the presence of soft-tissue involvement. Fever and transitory worsening in pain may occur secondary to inflammatory reaction in the hours following injection; however, these side effects usually resolve spontaneously within 1-3 days. The decision to perform therapeutic percutaneous injections should be made by a multidisciplinary team because the choice between this option and alternative methods of treatment depends on several factors including the location of the lesion, the local and general extent of the disease, the pain and functional disability experienced by the patient, and the patient's state of health and life expectancy.

Acetabulum↗
PubMedDate not supplied

Axial osteomalacia with sacroiliitis and moderate phosphate diabetes: report of a case.

We report a new case of axial osteomalacia diagnosed in a 51-year-old white Caucasian male, made particular by its association with sacroiliitis, positive HLA-B27 antigen, and also moderate phosphate diabetes responsible for a decreased appendicular bone mass. The diagnosis was suspected when X-ray evaluation showed increased density and coarse trabeculation mainly involving the pelvis and spine. Dual energy X-ray absorptiometry confirmed the elevated bone density at the lumbar spine (T score: +1.92) contrasting with a decreased bone mass at the femoral neck (T score: -2.33). The diagnosis was confirmed by histomorphometry of the iliac crest showing marked thickening of the cortices (2190 microns +/- 0.574, N = 780 +/- 40) and an increased trabecular bone volume (33.24%, N = 14 +/- 3). Osteoid parameters were also markedly increased with an osteoid volume of 2.1% (N = 1.2 +/- 0.5) and a mean osteoid thickness of 28.7 microns (N = 13 +/- 2.5), with a normal bone fluoride content (0.082%, N < 0.10). Bone resorption as assessed on bone biopsy and by the measurement of markers of bone remodeling (serum procollagen type I C-terminal telopeptide and 24 hr urinary cross-laps to creatinine ratio) was increased. This latter finding was not necessarily due to axial osteomalacia and could be the consequence of moderate phosphate diabetes. The patient was treated with calcitriol which was promptly discontinued due to gastrointestinal symptoms and replaced by calcidiol without any significant effect on the low back pain.

Absorptiometry, Photon↗
PubMedDate not supplied

[Normal and pathological aspects of the glenoid labrum in opaque arthro-scanner].

The morphology of the glenoid labrum was studied by CT arthrography in 88 patients. These were divided in 2 groups. In the first group, the patients underwent CT arthrography for a clinical instability of the shoulder. The second group was the reference group to study the morphology of the glenoid labrum, it included patients with rotator cuff tears or other pathology of the shoulder, without clinical instability. We described the normal labrum which presents important morphologic variations. Its study may be difficult because of the proximity of capsular structures of the shoulder, mainly the gleno-humeral ligaments. The normal variants and the pathologic aspects of the labrum were studied: the clefts, tears and degenerative phenomenous. The cleft aspect was studied comparatively in the instable population and in the reference population.

Arthrography↗