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Biomedical subjects

S J Golding

Publications and source records attributed to S J Golding.

At least 19 recordsLinked to original sources

A comparative study of evaluation of radiographs, CT and 3D reformatted CT in facial trauma: what is the role of 3D?

A panel of 17 trainee maxillofacial surgeons viewed 23 cases of facial trauma, demonstrated on radiographs, axial CT images and three-dimensional (3D) reformatted CT images in a standardized viewing format under standard conditions. Their diagnostic interpretation, extraction of information relevant to surgical management and subjective evaluation of each modality were recorded by standard questionnaire and compared with a gold standard evaluation by a consultant radiologist and surgeon reading based on results of clinical management. There were clear and measurable differences in the viewers' evaluations of radiographs, CT and 3D reformatted images. Overall, surgeons showed more accurate diagnostic reading of radiographs and 3D reformatted images. This was in contrast to their subjective assessment of the clinical value of each modality, which showed a strong preference for 3D over all other techniques and for CT over radiographs. However the perceived benefit of axial CT images over radiographs was not reproduced on objective testing in this group; surgeons appear to perform less well in interpreting CT images than their subjective response to the modality would suggest. This work has supported the view that surgeons value 3D imaging as a front-line tool in the evaluation and management of selected cases of acute facial trauma. We have demonstrated that the perceived benefits of 3D reformatted CT to surgeons appear real.

Facial Injuries↗

The role of MRI in facial swelling due to presumed salivary gland disease.

50 consecutive patients presenting with facial swelling thought clinically to be due to salivary gland disease underwent MRI. Examinations were interpreted by one radiologist without access to previous investigations. Records were reviewed to determine the reliability and role of MRI in patient management, and the contribution of other prior or subsequent investigations. MRI findings were verified against operative findings, percutaneous biopsy or clinical follow-up (periods ranging from 8-58 months). A mass was found in 27 patients; in 11 of these patients, disease was extrinsic to the salivary gland. MRI diagnosis of tumour was correct in all patients and MRI was a reliable investigation for planning surgical resection. No mass was found in 23 patients, 8 of whom had normal appearances. Evidence of salivary duct dilatation was seen in 12 patients and fatty infiltration was seen in 3. MRI findings appeared correct in all patients. Prior investigation was undertaken in 29 patients, including orthopantomography, ultrasound and sialography; none provided additional information. Sialography was carried out in three patients after MRI and concurred with MRI in all cases. MRI was an adequate basis for management in all patients and therefore appears to be an effective first line investigation of facial swelling. It is reasonable for patients to undergo preliminary investigation for dental sepsis, this being the most common cause of facial swelling. Further study is required to determine whether MRI can completely replace invasive sialography.

Adenoma, Pleomorphic↗

Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single kidney in the pig.

PURPOSE: Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single pig kidney were assessed. METHODS AND MATERIALS: The right kidney of 13 adult female Large White pigs was irradiated with a single dose of 9.8 Gy gamma rays. Animals were serially killed between 2 and 24 weeks postirradiation (PI); 1 h prior to postmortem each pig received 500 mg bromodeoxyuridine (BrdUrd). At postmortem, both kidneys were removed and tissue taken to prepare cell suspensions. The labeling index (LI) of these suspensions was measured using flow cytometry; in vivo BrdUrd incorporation in glomerular and tubular cells was determined immunohistochemically. The kidneys were also assessed histologically. RESULTS: Irradiation of the right kidney alone resulted in a significant increase in renal cell LI in both the irradiated and the contralateral unirradiated kidney within 2 weeks of irradiation; peak values of 1.57 +/- 0.32% and 1.04 +/- 0.13%, respectively, were seen 4 weeks PI, significantly greater (P < 0.001) than the preirradiation value of 0.18 +/- 0.01%. The LI values then declined with time, but remained greater than those seen prior to irradiation. A similar pattern of response was determined from counts of labeled glomerular and tubular cells identified immunohistochemically. The increase in labeled glomerular cells was seen 2 weeks PI, whereas that for the tubular cells did not occur until 4 weeks PI. The irradiated kidney exhibited diffuse, progressive glomerular alterations. In contrast, tubular damage was focal; the irradiated kidney also exhibited a prominent vasculopathy, involving arteriolar and peripheral interlobular artery thickening. The contralateral unirradiated kidney appeared unchanged. CONCLUSION: These findings confirm the hypothesis that the morphologic and kinetic responses observed after irradiation of a single kidney are similar to those observed after irradiation of both kidneys. Renal irradiation results in significant alterations in glomerular and tubular cell proliferation and morphology within 2-4 weeks of irradiation; glomerular changes appear predominant.

Animals↗

Magnetic resonance imaging in myelodysplastic syndromes.

In this study we used magnetic resonance imaging (MRI) to examine the axial bone marrow of 11 patients with myelodysplastic syndromes (MDS). T1 weighted images showed a reduction in signal intensity in all patients. The degree of reduction in signal intensity correlated with bone marrow cellularity rather than percentage blasts or French-American-British Co-operative group (FAB) classification. T2 weighted images showed an increase in signal intensity in 10 out of 11 patients; however, reliable grading was not possible using this sequence. Both T1 and T2 weighted images indicated a homogeneous pattern of disease within the axial skeleton in MDS. We have also shown that iron deposition in multiply transfused patients is a significant factor influencing signal reduction. The results of this study suggest that MRI may have a diagnostic role in MDS but is unlikely to be of value in staging.

Adult↗

Preliminary results of a modified surface rendering technique in the display of magnetic resonance angiography images.

Maximum intensity projections are the currently accepted method of displaying Magnetic resonance angiography (MRA) data. In this study, we introduce a modified surface rendering method for displaying this same MRA data. The system we have developed is designed to reconstruct three-dimensional (3D) images of vasculature using standard magnetic resonance images. A workstation was used for post-processing that is readily available and inexpensive. Software was written to process the original images and control the commercially available surface rendering algorithm while performing the reconstruction. The standard surface rendering technique was modified by including several velocities of blood flow in the reconstruction. These velocities were assigned varying degrees of translucency, which allow flow information to be included in the reconstructed images. Six subjects were examined using this technique and the images were compared with those from other imaging modalities. This surface rendering method has been shown to produce clearer and more comprehensible images of complex vasculature, both for radiologists, and for physicians of other disciplines. Its success is based on improvements in computing techniques and in acquisition of vascular MR images. The method shows great potential, and with future clinical trials, the true uses of this method will be discovered or confirmed.

Blood Flow Velocity↗

Patterns of lymphatic metastases at recurrence of prostate cancer: CT findings.

We describe the CT patterns of lymphadenopathy and visceral metastasis in 22 men with clinical features of recurrent prostate cancer. Fifteen of 22 men (68%) had lymphadenopathy with predominant retroperitoneal disease in seven cases, a feature noted particularly in men whose primary treatment had involved radical pelvic radiotherapy. A previously unreported 'pseudolymphoma' pattern of massive retroperitoneal disease with contiguous invasion of the perirenal space and adrenal glands was seen (three cases). Whilst staging examinations with CT (or MRI) at initial diagnosis of prostate cancer may be confined to the pelvis if no pelvic lymphadenopathy is found, evaluation of suspected recurrent disease requires examination of the abdomen and pelvis. CT appearances of advanced prostate cancer may mimic retroperitoneal lymphoma.

Aged↗

Radiation-induced changes in the kinetics of glomerular and tubular cells in the pig kidney.

Both kidneys of 13 mature female Large White pigs were irradiated with a single dose of 9.8 Gy 60Co gamma rays. The pigs were killed serially between 2 to 24 weeks after irradiation. One hour prior to sacrifice bromodeoxyuridine (BrdU) (500 mg/pig) was injected intravenously. At postmortem the kidneys were removed and tissue was taken to prepare cell suspensions. The labeling index (LI) of these suspensions was determined using flow cytometry. In vivo BrdU incorporation in tubular and glomerular cells was determined immunohistochemically. The kinetics of glomerular and tubular cells was evaluated by counting the number of labeled cells/glomerulus and the number of labeled tubular cells/field of view. An average of 1200 glomeruli and 1500 fields of view/time were counted. Similar analyses were performed on renal tissue from unirradiated control animals. Flow cytometry revealed rapid and significant increases in the LI of kidney cells; 2 weeks after irradiation the LI increased from a control value of 0.18 +/- 0.01 to 1.23 +/- 0.22% (P < 0.001). By 4 weeks the maximal value of 2.45 +/- 0.36% was seen; the LI then declined progressively but at 24 weeks after irradiation still remained significantly above control values (P < 0.001). A similar pattern of response was determined by counting the labeled glomerular and tubular cells identified immunohistochemically. However, the increase in labeled glomerular cells occurred 2 weeks after irradiation, whereas that for the tubules occurred 4 weeks after irradiation. These findings indicate that irradiation of the kidney, classically regarded as a "late-responding" organ, is associated with rapid and significant changes in the kinetics of both tubular and glomerular cells.

Animals↗

Influence of a low protein diet on radiation nephropathy in the pig.

Nine mature, approximately 45-week-old pigs, were fed a standard diet (SD) containing 16% protein; 10 pigs were fed an isocaloric low protein (LP) pig feed containing 4% protein 2 weeks prior to and 16 weeks after renal or sham-irradiation. The pigs then received the SD for a further 4 weeks. Both kidneys of seven pigs fed the LP diet, and six pigs fed the SD, were irradiated with a single dose of 9.8 Gy of 60Co gamma-rays. The remaining pigs received sham-irradiation. The individual kidney glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and the haematocrit were serially measured before and up to 20 weeks after irradiation. The radiation-induced reduction in mean individual kidney GFR, expressed as either absolute values or as a percentage of the respective sham-irradiated controls, was significantly greater in pigs fed the SD compared with pigs fed the LP diet (p < 0.05). In contrast, the radiation-induced reduction in mean individual kidney ERPF, expressed as absolute values, observed in pigs fed the SD was not significantly different from that seen in pigs fed the LP diet. However, if these data were expressed as a percentage of the respective sham-irradiated controls, then a significantly greater reduction in ERPF was seen in pigs fed the SD compared with pigs fed the LP diet (p < 0.001). Morphological analysis of renal tissue removed 20 weeks after irradiation showed that the extent and severity of the glomerular lesions seen in pigs fed the SD were significantly reduced in pigs fed the LP diet. Thus dietary protein restriction appears to reduce some of the signs of radiation nephropathy in the pig.

Animals↗

Sequential evaluation of radiation-induced glomerular ultrastructural changes in the pig kidney.

Both kidneys of 12 mature female pigs received either a single dose of 9.8 Gy 60Co gamma rays or sham irradiation. At intervals of 1-4 weeks serial renal biopsies were obtained, followed by sacrifice at 24 weeks after irradiation. Individual kidney glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and the hematocrit (Hct) were measured routinely. Renal irradiation resulted in a progressive decline in GFR, ERPF, and Hct, with minimal values being observed within 12 weeks of irradiation. No change in any of these parameters was noted in the sham-irradiated pigs. The initial morphological change in irradiated glomeruli was leukocyte attachment to capillary endothelial cells 3-6 weeks after irradiation followed by activation and swelling of the endothelial cells. This was followed by pronounced increases in capillary permeability with fluid and erythrocyte, leukocyte, and platelet exudation into the subendothelial/mesangial space. This resulted in compression of glomerular capillary lumina, which occurred concomitantly with the reduction in GFR. By 12 to 15 weeks after irradiation the changes in endothelial cells were less evident. However, mesangial cells exhibited evidence of activation and proliferation accompanied by progressive mesangial expansion and sclerosis. Thus the glomerular capillary endothelial and mesangial cells appear particularly important in the pathogenesis of radiation nephropathy.

Animals↗

Increasing patient throughput in magnetic resonance imaging: a practical approach. Oxford MRI Group.

A major factor governing the throughput of patients in a magnetic resonance imaging (MRI) service is the number and length of sequences employed. This study investigated the feasibility of prospectively selecting patients for whom a pre-planned examination of the brain, spine or knee could be applied with a high chance of success. The implications on throughput of using these pre-planned examinations were determined. 173 patients were studied. A successful outcome was defined as an examination in which a diagnosis could be made with 100% confidence and without the need for further sequences. Examinations of the brain (n = 113), knee (n = 23) and lumbar spine (for disc degeneration, n = 14) were performed with success rates of 96%, 87% and 64%, respectively. Examinations of the lumbar spine (for radicular symptoms, n = 20) and cervical spine (n = 3) were performed with success rates of 85% and 66%, respectively. The examinations of the brain, knee and lumbar spine (for disc degeneration) were completed within the target time of 20 min in 92%, 95% and 69% of cases, respectively. Examinations of the lumbar spine (for radicular symptoms) and cervical spine were completed within 30 min in 75% and 33% of cases, respectively. Analysis of our results suggests that success rates could be improved by minor changes in sequence design. Carefully selected patients can be successfully examined in short examination times. Instituting these practices would increase the efficiency of MR machine time and improve patient throughput by 80-125%. This would have a marked effect on the length of waiting lists, and would increase the general availability of MRI.

Brain Diseases↗

The effect of unilateral nephrectomy on the subsequent radiation response of the pig kidney.

The left kidney of 14 Large White female pigs, approximately 14 weeks of age, was surgically removed. Thirty weeks after unilateral nephrectomy (UN) the remaining kidney was irradiated with a single dose of between 11.9 and 15.6 Gy of 60Co gamma-rays; three pigs received sham irradiation. Following irradiation glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and haematocrit (Hct) were determined for up to 48 weeks after irradiation. Irradiation resulted in a dose-dependent decline in GFR, evident 8 weeks after irradiation. This was followed by a gradual improvement in GFR, although after doses of 14.0 Gy GFR remained below control values throughout the study. A similar pattern of response was seen in terms of ERPF, but this was not dose-related. Doses of greater than or equal to 14.0 Gy also caused a significant reduction (p less than 0.001) in Hct within 4-8 weeks. Minimal levels were evident 16 weeks after irradiation; Hct then increased, but remained below preirradiation values. Dose-effect curves were obtained by determining the percentage of irradiated kidneys which showed a greater than or equal to 50% reduction in GFR and ERPF, fitted by probit analysis, and ED50 values (+/- SE) were calculated for each parameter. The ED50 values for GFR and ERPF were 14.49 +/- 0.27 Gy and 12.56 +/- 0.98 Gy, respectively. These values were not significantly different from those obtained from intact age-matched pigs in which the right kidney alone was irradiated; UN did not compromise or alter the radiation response of the kidney to irradiation. However, the ED50 values obtained for the UN pigs were significantly greater (p less than 0.001) than the values of 9.76 +/- 0.17 Gy and 6.19 +/- 0.93 Gy, seen for GFR and ERPF in intact age-matched pigs in which both kidneys were irradiated. Thus although both experimental situations involved irradiating the entire renal tissue, the relative radiosensitivity of the kidneys varied considerably. These findings show that the radiosensitivity of the pig kidney can vary markedly, depending on the physiological status of the kidney at the time of irradiation.

Animals↗

Residual radiation-induced damage to the kidney of the pig as assayed by retreatment.

The effect of re-irradiation on the previously irradiated kidney was studied in the Large White female pig. Both kidneys of 14-week-old pigs were initially irradiated with a single dose of 3-7 Gy of 250 kV X-rays. The individual kidney glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and the haematocrit (Hct) were serially measured up to 24 weeks after X-irradiation. Doses of 3 and 5 Gy of X-rays had little effect on the GFR. However, 7 Gy of X-rays caused a marked decline in the GFR up to 12 weeks after irradiation; the GFR then began to recover. A similar pattern of response was seen in the ERPF. In contrast, the Hct was reduced in all pigs 4 weeks after X-irradiation. The extent of the decline and subsequent recovery 24 weeks after irradiation appeared to be related to dose. Twenty-four weeks after X-irradiation both kidneys were re-irradiated with a single dose of 7.9 Gy of 60Co gamma-rays; both kidneys of four age-matched control pigs which had not previously received X-irradiation were similarly treated. Individual kidney GFR, ERPF and Hct were again serially measured up to 24 weeks after gamma-irradiation. Re-irradiation resulted in a significantly greater reduction in the GFR, ERPF and Hct compared with that seen after gamma-irradiation alone. Moreover, the severity of the reduction in the GFR and Hct observed after gamma-irradiation was related, in a dose-dependent manner, to the initial X-ray doses employed. These results indicate that the kidney fails to exhibit complete long-term recovery in function following irradiation. Re-irradiation of the kidney in patients should thus be viewed with extreme caution.

Animals↗