Masters Degrees (Nuclear Medicine)

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Browsing Masters Degrees (Nuclear Medicine) by browse.metadata.advisor "Warwick, James"

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    Brain SPECT in patients with neuropsychiatric SLE : the additional value of semi-quantitative analysis
    (Stellenbosch : University Stellenbosch, 2009-12) Khider, Mohamed Abdelrahman; Warwick, James; Whitelaw, Dave; University of Stellenbosch. Faculty of Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Nuclear Medicine.
    ENGLISH ABSTRACT: Introduction: There is conflicting data on the value of single photon emission tomography (SPECT) for the diagnosis of neuropsychiatric SLE (NPSLE). Visual assessment of brain SPECT scans is the standard approach in clinical practice. However the definition and identification of significant changes may be limited by a high interobserver variability, especially in centres with limited experience. This may be reduced by a more objective semi-quantitative assessment. The objectives of this study were to determine the sensitivity and specificity of SPECT for the detection of NPSLE at our institution using visual assesment, to determine the additional value of using an objective semi-quantitative diagnostic criterion, and to investigate the correlation between abnormal perfusion pattern and clinical NPSLE classification in patients with active NPSLE. Material and methods: Nineteen patients with NPSLE and 19 normal controls were studied with brain SPECT. Scans were interpreted blindly by two nuclear medicine physicians using two methods; visual and semi-quantitative assessments. In the visual method, overall visual impression was recorded for each scan using a four point scale, where A=normal, B=probably normal, C=probably abnormal, and D=abnormal. In addition, each brain region was assigned a severity score from 0=normal perfusion to 3=severe hypoperfusion. In the semi-quantitative assessment, ten-band color scale was used, and perfusion deficit was quantified on the side with the lower color intensity comparing to the contralateral side. A score was given to the region with perfusion deficit according to the difference (in color bands) between the two hemispheres. Analysis was performed for the visual assessment method (overall impression and severity scores) and the semi-quantitative assessment method using a receiver operator characteristic (ROC) curve. Optimal cut-off points were determined and the accuracy of the different techniques was also compared statistically. Finally, the correlation was determined between the SPECT perfusion pattern and the clinical pattern of disease. Results: An ROC curve analysis for the overall visual impression resulted in an area under the curve of 0.76. At a cut-off point of C (probably abnormal), brain SPECT had 89% sensitivity and 57% specificity for the diagnosis of NPSLE. The severity score which include the total severity score and the modified total severity score resulted in areas under the curve of 0.75 and 0.79 respectively. The semi-quantitative assessment resulted in areas under the ROC curve of 0.80. Statistically, there was no difference between the overall visual impression, visual severity scores, and the semi-quantitative assessment. Agreement analysis between the SPECT pattern and clinical pattern of disease showed agreement in 91.6% in the diffuse pattern, whereas agreement in the focal pattern was seen in only 42.8%. Discussion and Conclusion: In this study, we found that brain SPECT is able to diagnose active NPSLE with a high sensitivity and moderate specificity. The overall visual impression, visual severity scores, and the semi-quantitative assessment showed no significant differences between the techniques. The use of the semi-quantitative assessment described may be useful in centers with limited experience in the interpretation of brain SPECT. The correlation between the SPECT pattern and clinical disease pattern may provide some insights into the pathophysiology of NPSLE.
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    Optimal utilization of gamma camera time in Tc-99m MDP bone scintigraphy
    (Stellenbosch : University of Stellenbosch, 2007-03) Jawa, Zabah Muhammad; Rubow, Sietske; Warwick, James; University of Stellenbosch. Faculty of Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Nuclear Medicine.
    Introduction: Whole body bone scintigraphy with Tc-99m MDP is able to provide a survey of the entire skeleton. The question arises if it is mandatory to perform a whole body bone scan in all patients, irrespective of the clinical indication. The aim of this study is to determine the implications of performing limited imaging in patients who had whole body bone scan for various clinical patholgy with Tc-99m MDP, in order to determine if limited imaging would be acceptable in selected pathologies. This may enable gamma camera time to be optimally utilized in units with limited facilities. Materials and Methods: Reports of 3015 patients with various clinical pathologies who had whole body bone scans with Tc-99m MDP in our department from January 2002 to December 2004 were retrospectively reviewed. The presence of pathologic radiotracer uptake was analyzed in order to establish the pattern of distribution. Clinically significant skeletal lesions were classified according to the anatomical regions where they were located viz; skull (including the neck), axial skeleton (including the pelvis and shoulders) and limbs. Results: Our results showed that in patients with lung cancer, soft tissue sarcoma, and myeloma, there was an error in more than 25% of patients when limited imaging was performed. In patients with cancer of the breast, prostate, kidney, gastrointestinal system, and reproductive system and lymphoma there is an error in less than 5% of patients when limited imaging is employed. For iv patients with more localized musculoskeletal disorders such as suspected stress fractures, complicated joint prosthesis and avascular necrosis of the femur head, regional imaging of the area of pathology showed a percentage error of less than 6%.
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    Semiquantitative analysis of FDG PET brain scans using Neurostat and SPM
    (Stellenbosch : Stellenbosch University, 2021-12) Munemo, Lionel Tapiwa; Doruyter, Alex G. G.; Warwick, James; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Medical Imaging and Clinical Oncology. Nuclear Medicine.
    ENGLISH SUMMARY : Background: Positron emission tomography using Fluorine-18 2-Fluoro-2-Deoxy-D-Glucose (FDG-PET) has an established role in the investigation of multiple neurological conditions such as neurolupus and epilepsy. FDG PET brain scans are interpreted visually and semi-quantitatively using tools such as Neurostat or SPM. The normal databases used in Neurostat were created over 20 years ago, however since this time there has been a steady advance in camera technology and reconstruction algorithms for semiquantitative analysis. It is possible that results obtained with semiquantitative analysis using Neurostat (old PET databases) are different from results obtained with semiquantitative analysis using SPM (using a new PET database). The aim of this study was to evaluate whether there are differences in study interpretation when the same scans are read in combination with a Neurostat analysis, compared to when they are read in combination with an SPM analysis using a database built with new scan data. Methods: First, a local normal database was built with healthy control data using MATLAB R2014b and SPM12. These scans were obtained from previous research projects and prospectively enrolled participants. All scans were acquired on a Philips Gemini-TF Big bore PET/CT scanner. Second, a test dataset, comprising a mixture of clinical scans and scans of prospectively enrolled participants (other than those included in the normal database), was used to compare interpretation of results when using the SPM-based normal database (SPM) to interpretation results when using Neurostat (NS). Results: A database of normal FDG Brain PET/CT studies for the 19-35 year age group was created from a total of 26 healthy controls (13 men and 13 women – optimally matched for age and gender). The test dataset was comprised of 20 scans in the same age range: 15 clinical cases and 5 controls. Next, two expert readers read scans in the test dataset with the assistance of both the NS outputs and the SPM outputs, in separate reading sessions. There was no statistically significant difference in whether a scan was called normal or abnormal using either Neurostat or SPM. There was also no significant difference when comparing the number of lesions identified. SPM scored lesions as less severe than Neurostat (p=0.006). Conclusion: SPM-based analysis using a locally-developed normal database (with scans acquired on a modern PET-CT scanner) yielded similar results to Neurostat, justifying its continued use. Further evaluation to determine if these results are applicable to older patients with neurodegenerative conditions such as Alzheimer’s disease is planned.