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Biomedical subjects

W M Park

Publications and source records attributed to W M Park.

At least 19 recordsLinked to original sources
PubMed1992

Electrode-derived myocardial pH measurements reflect intracellular myocardial metabolism assessed by phosphorus 31-nuclear magnetic resonance spectroscopy during normothermic ischemia.

To determine the ability of extracellular myocardial tissue pH measured with an intramural electrode to reflect myocardial intracellular metabolic status during normothermic ischemia, we studied 14 open-chest dogs with in vivo phosphorus 31-nuclear magnetic resonance spectroscopy during left anterior descending coronary artery occlusion (experimental group, group I, n = 7) or after a sham operation (control group, nonischemic, group II, n = 7). Phosphorus nuclear magnetic resonance spectra were acquired every 5 minutes at 4.7 tesla (256 averages, TR = 1000 msec, pulse width = 30 microseconds) with a 2 cm two-turn radiofrequency surface coil. Intracellular myocardial adenosine triphosphate peak area was normalized to an external phosphate standard. The change in adenosine triphosphate peak area was expressed as percent of baseline value. During 3 hours of normothermic ischemia the observed extracellular myocardial pH correlated with nuclear magnetic resonance-calculated myocardial pH in the ischemic dogs with an average r value of 0.94 (p less than 0.0001). During this same interval, the fall in extracellular myocardial pH correlated with the loss of adenosine triphosphate peak in each ischemic dog, with an average r value of 0.91 (p less than 0.0001). Thus extracellular myocardial pH, measured with an intramural electrode, correlated with nuclear magnetic resonance-derived myocardial pH and loss of myocyte adenosine triphosphate peak content and reflected the metabolic status of the myocyte during ischemia. These data validate the use of extracellular myocardial pH to assess the adequacy of myocardial preservation during aortic crossclamping for cardiac operations.

Adenosine Triphosphate↗
PubMed1985

Spondylarthrography: the demonstration of spondylolysis by apophyseal joint arthrography.

Twenty selected patients with spondylolysis have been studied following apophyseal joint arthrography. In each instance a communication with the defect of the pars interarticularis was demonstrated by the extension of contrast medium from injection into the adjacent facet joint. The clinical and radiological features are described. The anatomical basis of the abnormality is presented using macroscopic and radiographic correlation from a dissected cadaveric specimen of spondylolysis. Sixty-five per cent of the patients experienced significant relief of pain symptoms when long-acting local anaesthetic was introduced into the facet joint.

Adult↗
PubMed1985

Acute traumatic intraosseous disc herniation.

The clinical, radiologic, and discographic findings are reviewed in eight patients with acute traumatic intraosseous disc herniation. The syndrome should be considered in adolescent patients having severe back pain with limited radiation to the upper thigh, following significant compression/flexion stress to the spine. The intraosseous disc herniation can be confirmed by discography and reproduction of symptoms during the procedure is a helpful confirmatory feature. The radiologic natural history of the lesion is presented, and the role of bone scintigraphy is discussed. This type of injury may be responsible for considerable pain and disability in the adolescent age group and has proved extremely difficult to manage except by conservative treatment and analgesics.

Acute Disease↗
PubMed1985

Fracture of the cervical spine in ankylosing spondylitis.

The radiological features, clinical findings and mortality rates of patients with ankylosing spondylitis complicated by cervical trauma have been reviewed. All patients had long-standing disease and half had sustained their fractures as a result of trivial accidents. There were 19 cervical fractures in 18 patients, which were chalkstick in type and occurred predominantly at the 6th and 7th cervical levels. Ten fractures passed through the upper part of the vertebral body, one through the mid-vertebral body and the final eight were through the disc space. The site of the fracture line was related to neurological outcome. Those patients whose fracture line ran through the disc space had significantly less neurological injury and a much better prognosis. Distraction at the fracture site had some relation to prognosis but horizontal displacement and angulation were not found to be of importance. This study confirms that cervical fracture with neurological complications may follow minor trauma in ankylosing spondylitis. The site of the fracture in relation to the vertebral bodies and discs appears to be of some prognostic relevance and careful radiological assessment of all patients with ankylosing spondylitis and cervical injury should be undertaken.

Adult↗
PubMed1983

The diagnostic value of bone scintigraphy in patients with low back pain.

Bone scintigraphy has been studied in two groups of patients presenting with low back pain. In one group of 38 patients suffering "nonspecific" back pain, bone scintigraphy and laboratory findings were negative in 24. There were abnormal laboratory findings in all of the remaining 14 and 7 had positive bone scans indicative of clinically significant disease. Selection of patients for bone scintigraphy in this group should therefore be influenced by abnormal laboratory findings and elevation of the erythrocyte sedimentation rate in particular. By comparison, the bone scans were reviewed from another group of patients suffering previously known malignancy. Out of 138 patients, nearly 40% showed a positive bone scan due to subsequently proven metastasis. Bone scintigraphy was positive in a further 14% as a result of osteoporotic rib fracture and vertebral body collapse. In half of these, it was not possible to exclude malignancy by scintigraphy. The present findings indicate that bone scintigraphy is not a useful procedure in patients with long-standing low back pain who have normal radiographs and normal laboratory findings.

Adult↗
PubMed1983

Observer variation in skeletal radiology.

The factors that affect observer variation in bone radiology are analysed from data in the literature and on the basis of studies carried out at McMaster University on the hands and sacroiliac joints. A plea is made for presenting results in terms of Kappa statistics so that agreement due purely to chance is eliminated. In the conclusions the main variables that affect concordance are listed so that strategies can be developed to reduce observer variation. This is important in serial studies to ensure that the observer variations are smaller than the effect one wishes to measure.

Age Determination by Skeleton↗
PubMed1983

Gallium 67 scanning in rheumatoid arthritis.

Gallium 67 scans were performed on both knees of 38 patients with rheumatoid arthritis. There was a significantly higher level of 67Ga accumulation in those knees with clinically active synovitis (p less than 0.001). Synovial white cell concentration was also elevated in the group with active synovitis. The white cell concentration correlated with the 67Ga knee/femoral ratio at the p less than 0.001 level. 67Ga activity in the synovial fluid was predominantly in the supinate and activity was also present in the synovium. The findings indicate that 67Ga uptake occurs in rheumatoid joints and reflects the degree of synovial inflammation.

Arthritis, Rheumatoid↗
PubMed1982

Severe kyphosis due to congenital dorsal hemivertebra.

Kyphotic deformity arising from failure of the formation of a vertebral body is described in nine patients. The study of the natural history demonstrates the progressive nature of this disorder resulting in severe deformity and neurological embarrassment. Early radiological recognition of this congenital deformity is essential and tomography is important in the early assessment. Tomography combined with myelography is essential to delineate the extent of bony abnormality and cord compression in severe kyphosis in order that adequate decompression and reconstructive surgery can be performed.

Adolescent↗
PubMed1981

Gallium-67 scanning in the painful total hip replacement.

Pain following total hip replacement is a significant clinical and diagnostic problem. Technetium scanning has proved a sensitive indicator of infection or loosening but does not differentiate between them. This study assessed the value of gallium-67 to aid this differentiation. Thirty patients underwent revision surgery. Fourteen were proven to be infected and 13 had positive gallium scans as also did two patients without infection. The implications of these false interpretations are discussed. Increased gallium activity was correlated with the patterns of the 99mTc scans and arthrographic appearances. It is concluded that gallium-67 scanning is a valuable adjunct to the assessment of the painful hip replacement when infection is suspected.

Aged↗
PubMed1981

The detection of spinal pseudarthrosis in ankylosing spondylitis.

Spinal pseudarthrosis in ankylosing spondylitis can be difficult to detect radiologically. This paper assesses the value of bone radioscintigraphy in relation to radiological examination. The patterns of tracer uptake in the spine were recorded in 16 patients in whom established ankylosing spondylitis was complicated by pseudarthrosis. Twenty such lesions were identified in 16 patients, mostly occurring at one level in a junctional region of the spine. Four patients had two lesions. Standard radiography failed to demonstrate this abnormality in seven patients and in these, tomography was required to confirm the scintigraphic findings. On the other hand, bone scanning was much less accurate in detecting the minor forms of marginal vertebral end plate destruction (spondylo-discitis) than conventional radiology. This study suggests that 99TcmMDP scanning is a useful primary investigation for the detection of spinal pseudarthrosis in patients with chronic ankylosing spondylitis who suffer late onset back pain.

Adolescent↗
PubMed1981

Diaphyseal osteosarcoma.

Fifteen cases of diaphyseal osteosarcomas were found in a review of 157 cases of long bone osteosarcoma (9.5%) and two further examples were added. The clinical and histological features of the diaphyseal osteosarcomas were indistinguishable from those of the commoner juxta metaphyseal osteosarcomas. The radiological features, however, fell into four distinct patterns: Group I had the classical appearance of a conventional osteosarcoma; Group II showed dense cortical sclerosis with bony expansion but no soft tissue swelling or break of the cortex at presentation; Group III presented with a pathological fracture through a purely osteolytic lesion; Group IV usually had the classical appearances of an osteosarcoma in the diaphysis but had, in addition, dense separate sclerotic lesions which were proximal to the tumour in the humerus and distal to it in the femur. The importance of these four groups lies in the quite distinct differential diagnosis which each presents.

Adolescent↗
PubMed1981

Alterations in vertebral growth following prolonged plaster immobilisation.

Long-term immobilisation in serial plasters for scoliosis, including the period of the adolescent growth spurt, leads to an increase in height of the vertebral bodies and a decrease of their height to width ratio. These changes are at the expense of the disc which is reduced in thickness. This stimulating effect on the vertebral body growth is probably due to the changes in mechanical factors.

Adolescent↗