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Biomedical subjects

I Watt

Publications and source records attributed to I Watt.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Magnetic resonance imaging in osteoarthritis of the knee: correlation with radiographic and scintigraphic findings.

Twelve knees with a range of severity of knee osteoarthritis were assessed by magnetic resonance imaging (MRI) and technetium-99m labelled hydroxymethylene diphosphonate scintigraphy. Five magnetic resonance pulse sequences were evaluated. Proton density (TR = 1000, TE = 26 ms) and STIR (TR = 1500, TI = 100, TE = 30 ms) were chosen for further use. Abnormalities shown by MRI included joint effusions, meniscal disruption, hyaline cartilage thinning, subchondral signal changes, pseudocysts, and heterogeneity of signal from osteophytes. Certain MRI and scintigraphic appearances correlated: (a) 'hyperintense osteophytosis' and ipsilateral 'tramline' scintigraphic uptake, suggesting increased fat content in 'active' osteophytes; (b) subchondral signal change and 'extended' pattern, possibly reflecting inflammation, synovial leak, or fibrovascular repair; (c) patellofemoral joint signal changes and patellar isotope uptake.

Aged↗
PubMed1990

Osteoarthritis revisited.

Current research challenges the concept that osteoarthritis is an inevitably progressive disease. Evidence suggests that many factors are involved and that the radiological features represent a spectrum of bone and joint response to disease, rather than reflect disease as such.

Aging↗
PubMed1990

Erosive osteoarthritis: is it a separate disease entity?

Erosive osteoarthritis (EOA) characteristically involves the hands of middle-aged women. The diagnosis is essentially radiological and depends upon the presence of articular surface erosions. This study investigates whether this radiological feature is a marker of a specific clinical entity. From a series of 500 consecutive patients attending a rheumatology clinic with symptomatic limb joint osteoarthritis, 24 were identified by radiological criteria to have EOA. These were age-sex matched with 24 patients from the same series who presented with osteoarthritis of the hand. Those with EOA had nearly twice as many radiographically abnormal joints in the hands as the controls (274: 144). This was almost entirely due to an increase in distal (134: 68) and proximal (79: 24) interphalangeal joint involvement, 71% of which were erosive. Erosions were found apart from the hands in both elbows of one patient with EOA. Otherwise only minor differences were present between the two groups in terms of distribution and incidence of osteoarthritic changes. There were no distinguishing serological or other clinical differences. This study has demonstrated that erosions in EOA are associated with more severe hand disease but are not apparently a marker of a separate disease entity. EOA appears to be an aggressive acute form of hand osteoarthritis and may represent the hand equivalent of similar forms of osteoarthritis in the shoulder, hip and knee.

Adult↗
PubMed1990

The Felty syndrome: a case-matched study of clinical manifestations and outcome, serologic features, and immunogenetic associations.

Thirty-two patients with the Felty syndrome, defined by the presence of rheumatoid arthritis, splenomegaly, and neutropenia, have been studied in comparison with 32 patients with rheumatoid arthritis matched for age, sex, and disease duration, and 9 patients with rheumatoid arthritis and idiopathic neutropenia. Patients with the Felty syndrome had severe destructive arthritis, which progressed during follow-up despite little evidence of objective synovitis, and a higher frequency of extra-articular manifestations, including vasculitis. Bacterial infection tended to occur in patients with the lowest neutrophil count but continued to occur in some despite normalization of the WBC. Prognosis was poor and 8 deaths occurred, predominantly from sepsis. Serologic features were prominent. High titers of IgG rheumatoid factor and circulating immune complexes characterized patients with persistent neutropenia. A family history of rheumatoid arthritis was more common in patients with the Felty syndrome. The association with HLA DR4 was very strong; in addition there was an increased frequency of the DQw3 variant, 3b, suggesting that HLA Class II genes in linkage with DR4 may contribute to disease expression.

Adult↗
PubMed1989

Laparoscopy, ultrasound and computed tomography in cancer of the oesophagus and gastric cardia: a prospective comparison for detecting intra-abdominal metastases.

We have evaluated the sensitivity, specificity and accuracy of laparoscopy under general anaesthesia, ultrasound and computed tomography (CT) in detecting intra-abdominal metastases in 90 consecutive patients with carcinoma of the oesophagus or cardia. Metastases were histologically confirmed as hepatic in 25 patients, nodal in 35 and peritoneal in nine. All investigations had high specificity (86-100 per cent) for each type of metastasis. Laparoscopy was found to be significantly more sensitive (P less than 0.01; P less than 0.02) and more accurate (P less than 0.01; P less than 0.01) than either ultrasound or CT, respectively, with regard to hepatic status. Although laparoscopy performed best with regard to nodal metastases, this reached statistical significance only when sensitivity of ultrasound was compared (P less than 0.01). Neither ultrasound nor CT detected any peritoneal metastases, although laparoscopy detected eight out of nine, giving a sensitivity of 89 per cent and an accuracy of 98 per cent. There was no morbidity or mortality associated with laparoscopy, which offers a safe, reliable method of determining intra-abdominal status and may obviate the need for surgery in some patients with malignant dysphagia.

Abdominal Neoplasms↗