Search PubMed⌕ Search

Biomedical subjects

I Watt

Publications and source records attributed to I Watt.

At least 91 records · Page 5Linked to original sources
PubMed1993

Magnetic resonance imaging of bone destruction in rheumatoid arthritis: comparison with radiography.

Bony changes in forty-four knees of patients with clinically established rheumatoid arthritis (RA) were examined using magnetic resonance imaging (MRI) and plain film radiography. In all cases MRI was clearly superior to radiographs, demonstrating 25 marginal erosions and 42 subchondral cysts, while the number seen on radiographs was 3 and 8, respectively. These results emphasize the problems in visualizing bone erosions in large joints using plain films. MRI is the method of choice for detecting early changes in RA, not only because of its high sensitivity, but also because of the ability of contrast-enhanced MRI to provide physiological characterization of these lesions.

Adult↗
PubMed1993

Post-traumatic osteoporosis and algodystrophy after external fixation of tibial fractures.

The incidence of two forms of post-traumatic osteoporosis and algodystrophy in the ankle region of 20 patients with displaced diaphyseal fractures of the tibia treated with external fixation were studied. Acute localised osteoporosis (ALO) occurred in 14 (70 per cent) and 5 (25 per cent) developed algodystrophy. ALO was significantly less frequent in matched patients treated by internal fixation or by external plaster-of-Paris (POP) cast. Regional osteoporosis (RO) was most common in POP patients. The presence of ALO may indicate the development of algodystrophy following tibial fracture. Our findings suggest that external fixation may predispose to ALO and algodystrophy.

Acute Disease↗
PubMed1993

Precontrast and postcontrast (Gd-DTPA) magnetic resonance imaging of hand joints in patients with rheumatoid arthritis.

In an attempt to demonstrate whether clinically selected joints of the hand in active rheumatoid disease had consistent MRI findings, 45 patients were examined, in whom one joint in each was selected by both the referring clinician and patient as being active and symptomatic. Such joints, in order to be included in the study, were required to conform to ARA criteria of activity and usually mild to moderate X-ray changes. The joints were imaged using spin-echo sequences with T1W and T2W precontrast images, followed by T1W images after intravenous administration of Gd-DTPA. Different patterns of joint abnormalities were found. In 27 joints MRI findings suggested highly active synovitis and/or destructive pannus. In four, crescentic enhancement was thought to be compatible with simple synovitis, but in 23 rounded masses of synovial proliferation were characterized by marked, diffuse contrast enhancement on T1W postcontrast images, which corresponded well with high signal intensity on T2W images. Synovial proliferation in a further 12 joints was shown by only moderate stippled contrast enhancement and nonhomogeneous intermediate to high signal intensity on T2W images. These findings were thought to represent less active synovitis and pannus. MRI did not demonstrate inflammatory activity in six joints. In two of these pannus was of low signal intensity on T2W images, without contrast enhancement after Gd-DTPA infection presumed fibrotic and inert, and four were normal on all pulse sequences. These results suggest that clinical features of synovitis, even in carefully selected joints clinically, do not produce a homogeneous group when examined by MRI imaging. Indeed, a spectrum exists from presumed marked, active synovitis to total normality. If MRI is to be used as a clinical and research tool in the assessment of rheumatoid disease, and its therapeutic manipulation, these results are of some importance, since the variable findings indicate an appreciable heterogeneity of appearances in joints thought clinically to be of relatively uniform severity.

Adult↗
PubMed1993

Pyrophosphate arthropathy: a prospective study.

One hundred and four consecutive patients with pyrophosphate arthropathy were followed prospectively and re-studied at a mean of 4.6 years. Sixty-four patients (43F, 21M; mean age at review 71.2 years) completed the study (24 died of unrelated disease, 16 were unavailable for review). The knee had been the major presenting joint in 91%. Symptoms were improved in 41%, unchanged in 33% and had worsened in only 27%: 27% developed symptoms in new joints. Radiographic changes of arthropathy were unaltered in 50%: although 'worsening' of previously involved joints was seen in 16%, the most common change was increase in osteophyte with bone remodelling (31%). Despite dynamic changes in chondrocalcinosis in most patients (77%) there was no correlation between extent of calcification and progression of arthropathy. It is concluded that the outcome of pyrophosphate arthropathy is not necessarily progressive, patients presenting with acute attacks alone do particularly well.

Adult↗
PubMed1993

The expression of rheumatoid arthritis in Malaysian and British patients: a comparative study.

Seventy consecutive patients with definite or classical RA attending a University Hospital Rheumatology Clinic in Malaysia, were compared with an age, sex, disease duration matched group of RA patients seen in a British University Hospital. There were no differences in measures of disease activity, overall functional status or serological status in the two groups. However significant differences were seen in both the articular and extra-articular manifestations of the disease in the two countries. British patients had more severe disease in the feet, and a higher prevalence of nodules, vasculitis and pulmonary fibrosis. The Malaysian population had fewer erosions, more frequent involvement of the wrists and cervical spine, and a much higher incidence of secondary sicca syndrome. Radiographic changes were generally milder in Malaysian patients. Possible reasons for these differences in the expression of RA in the two countries are discussed.

Adolescent↗
PubMed1993

A two-year, placebo-controlled trial of non-steroidal anti-inflammatory therapy in osteoarthritis of the knee joint.

Eighty-nine patients with established OA of the knee joint, already on regular NSAIDs for joint pain, were randomly allocated to receive 100 mg/day of slow release diclofenac (45 patients) or matching placebo (44), in place of their NSAID, for 2 years. Thirty-eight patients withdrew or dropped out of the study. The major causes for withdrawal were lack of efficacy (three active, 12 placebo, P < 0.01) or side effects (six active, five placebo), and most withdrawals occurred within the first 6 months. Long term follow up of these patients was not possible. Fifty-one patients completed the study (31 active, 20 placebo), 35 of whom reported that they were the same or better at the end of the 2-year period than at the beginning. Most of the recorded clinical parameters showed little or no change over 2 years in these 51 subjects, and in 70% there was no detectable change in the radiographs. We conclude that long term placebo-controlled trials are both feasible and ethical in knee OA, but that conventional clinical and radiographic techniques detect very little change in joint structure or function over a 2-year time period. This may reflect the insensitivity of the methods used to assess progression rather than absence of change. The fact that 20 of 44 patients changed from an NSAID to placebo completed the 2-year study without any symptomatic penalty indicates that not all patients entered needed or responded to NSAIDs.

Adult↗
PubMed1992

Soft-tissue localization of 99mTc-hydroxymethylene diphosphonate due to interaction with calcium.

Soft tissue localization of 99mTc-labelled bone imaging agents is often associated with high calcium levels either locally or systemically. This could be due to the formation of a large molecular complex after administration of the radiopharmaceutical. We have investigated the formation of such a complex between 99mTc-hydroxymethylene diphosphonate (HMDP) and calcium by a number of techniques. The results indicate that 99mTc-HMDP is a colloidal preparation which may contain particles up to 280 nm in size, and that the labelled colloid may aggregate in the presence of calcium salts forming particles up to 3 microns. Such particles are too large to permit free diffusion across vascular epithelium but large enough to localize in the liver or lungs. It is suggested that this interaction may be responsible for soft tissue localization of the technetium-labelled bone imaging agents. In vivo the radiolabelled complex in a mixture of 99mTc-HMDP and calcium chloride localizes to a significantly larger extent in liver, spleen and muscle and less in bone compared with 99mTc-HMDP diluted with saline. The increased liver and spleen uptake can be prevented by prior administration of non-radioactive colloid but this does not significantly improve the bone uptake of the 99mTc-HMDP/calcium chloride mixture. The clinical relevance of these findings lies in their possible explanation for soft-tissue uptake and poor bone accumulation of the technetium-labelled diphosphonates in some patients. This may be particularly important in evaluating quantitative bone scans, especially if serial scanning is done to monitor disease progress or therapy since local or systemic calcium levels may change between scans.

Animals↗
PubMed1992

Review of the use of MRI in soft tissue lesions.

The MR images of 34 patients with soft tissue lesions were retrospectively evaluated to assess the accuracy of the technique in distinguishing benign from malignant lesions, and to assess the usefulness of various criteria in making this distinction. The overall sensitivity for the detection of malignancy was 75% with a specificity of 94%. Size of lesion was found to be a good criterion in predicting malignancy, lesion margin and signal intensity were less useful. The tissue type was determined in a few instances where signal characteristics were typical, notably lipomas and neural tumours, but this was not reliable and in most lesions the tissue of origin cannot be determined on MR imaging and biopsy is necessary.

Adolescent↗
PubMed1992

Scintigraphic assessment of osteoarthritis of the knee joint.

Clinical, radiographic, and scintigraphic abnormalities of the knee joint have been correlated in a cross sectional study of 100 patients with osteoarthritis. The group comprised 73 women and 27 men with a mean age of 65.7 years. One hundred and ninety one of the 200 knees had clinical (175) or radiographic (185) evidence of osteoarthritis, or both (161). Scintigraphic images of the knees were obtained 4-5 minutes (early phase) and 2.5-3.5 hours (late phase) after intravenous injection of 600 mBq of technetium-99m diphosphonate. Abnormal images were recorded in 162 knees (81%), and six different patterns were detected. Generalised isotope retention around the knee (early or late phase) was less common than focal areas of uptake around the joint margin (early or late phase) or in the patella or subchondral bone (late phase). Some knees with abnormal scans were normal on radiography (n = 7), or vice versa (n = 21). Different scan patterns correlated with different clinical and radiographic features: the generalised pattern correlated with pain (odds ratio (OR) = 45.1) and osteophytes (OR = 48.3); joint line retention correlated with subchondral bone sclerosis on radiography (OR = 62.1); and subchondral bone retention correlated with more severe radiographic changes. It is concluded that different patterns of scintigraphic abnormality reflect various aspects of the disease process of osteoarthritis.

Aged↗
PubMed1992

Imaging of soft tissue tumors.

The evaluation of many soft tissue lesions remains a diagnostic dilemma for both the radiologist and the clinician. In recent years MR imaging has emerged as the modality of choice for the assessment of soft tissue tumors, with well-documented advantages over CT and other imaging techniques.

Humans↗
PubMed1991

Hip arthropathy in genetic hemochromatosis. Radiographic and histologic features.

Genetic hemochromatosis, a disorder of iron metabolism, results in the deposition of massive amounts of iron in the tissues. Arthropathy is one of a number of clinical features associated with the disease. Characteristic radiographic features in the wrist and hand have been reported, and an increased incidence of severe hip disease has been observed. In this study, hip radiographs of 112 patients with genetic hemochromatosis and arthritis were reviewed, and histologic examination of 2 femoral heads was performed. Twenty-eight of the 112 patients (25%) had evidence of arthritis of the hip joint. In 23 (82%) of the 28 patients, this feature was thought to be associated with osteoarthritis; 2 of these patients had an atypical arthropathy associated with radiolucency of the femoral head and histologic features of atypical stripping of the cartilage from the subchondral bone. These atypical features were not thought to be due to avascular necrosis, pyrophosphate-associated arthropathy, apatite-associated deposition arthritis, or osteoarthritis, but may be typical of genetic hemochromatosis and possibly the result of increased susceptibility to shearing forces at the bone-cartilage interface. In 5 of the 28 patients (18%), chondrocalcinosis was the sole abnormal finding on radiography. Ten of the 28 patients eventually required hip surgery, which confirms the severity of the hip disease associated with genetic hemochromatosis.

Adult↗
PubMed1991

MRI of the cervical spine: rheumatoid arthritis compared with cervical spondylosis.

This study is a comparison of the cervical spine MR images from 26 patients with rheumatoid arthritis of the cervical spine with those from an age and sex matched group suffering from cervical spondylosis. Erosion of bone and major atlanto-axial subluxation were confined to rheumatoid arthritis. Soft tissue changes revealed by MRI included distortion of normal ligaments and bursae around the dens, particularly in rheumatoid arthritis. Abnormal masses of soft tissue were found in both groups, but those suggesting acute inflammation were much more frequent in rheumatoid arthritis than in cervical spondylosis. Neural compression was well demonstrated, and in rheumatoid arthritis was usually caused by bony structures whereas in cervical spondylosis it was usually due to disc material. It is concluded that MRI should be used as the first investigation to follow plain films in rheumatoid arthritis of the cervical spine. Bone and soft tissue changes are clearly shown, but interpretation of the images requires the recognition that some observed abnormalities may be due to coincidental cervical spondylosis.

Adult↗