Thesis (MScMedSc (Medical Imaging and Clinical Oncology. Nuclear Medicine))--University of Stellenbosch, 2010. / Thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Nuclear Medicine at Stellenbosch University. / 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. / AFRIKAANSE OPSOMMING: Inleiding: Daar is teenstrydige inligting oor die waarde van brein enkelfoton emissie tomografie (EFET) vir die diagnose van neuropsigiatriese SLE (NPSLE). Visuele beoordeling van brein EFET flikkergramme is die standaard benadering in kliniese praktyk. Die definisie en identifisering van betekenisvolle veranderinge mag egter beperk word deur 'n hoë inte-waarnemer wisseling, veral in sentra met beperkte ondervinding. Dit mag verminder word deur 'n meer objektiewe semi-kwantitatiewe beoordeling. Die doel van hierdie studie was om 1. Die sensitiwiteit en spesifisiteit van EFET vir die opspoor van NPSLE in ons instelling te bepaal, 2. Die bykomende waarde van 'n objektiewe semi-kwantitatiewe diagnostiese kriterium vas te stel, en 3. Die korrelasie tussen 'n abnormale perfusiepatroon en 'n kliniese NPSLE klassifikasie in pasiënte met aktiewe NPSLE te ondersoek. Materiaal en Metodes: Negentien pasiënte met NPSLE en 19 normale kontroles is met brein EFET bestudeer. Flikkergramme is blind deur twee kerngeneeskundiges geïnterpreteer, deur gebruik te maak van twee metodes, 'n visuele en semi-kwantitatiewe beoordeling. Vir elke flikkergram is 'n globale visuele indruk genoteer deur gebruik te maak van 'n 4-punt skaal, waar A=normaal, B=waarskynlik normaal, C= waarskynlik abnormaal, en D=abnormaal. Bykomend is 'n ernstigheidsgraad waarde van 0=normale perfusie tot 3=erge hipoperfusie vir elke breinstreek toegeken. Vir die semi-kwantitatiewe beoordeling is 'n telling vir streke met laer intensiteit vergeleke met die kontralaterale kant toegeken, volgens die verskille in kleurbande deur gebruik te maak van 'n tienbandskaal. Die visuele metodes vir die globale indruk, visuele ernstigheidsgraad waarde, en die semi-kwantitatiewe beoordeling is geanaliseer deur 'n relatiewe funksioneringskenmerk (receiver operator characteristic (ROC)) kurwe te gebruik en optimale afsnypunte te bepaal. Die akkuraatheid van die verskillende tegnieke is ook statisties vergelyk. Laastens is die korrelasie tussen die EFET perfusiepatroon en die kliniese siektepatroon bepaal. Resultate: 'n ROC kurwe analise vir die globale visuele indruk het gelei tot 'n area onder die kurwe van 0.77. By 'n afsnypunt van (C) het brein EFET 'n sensitiwiteit van 89% en 'n spesifisiteit van 57% vir die diagnose van NPSLE gehad. Die visuele ernstigheidsgraad telling, en die semi-kwantitatiewe beoordeling het onderskeidelik tot areas onder die ROC kurwe van 0.75 en 0.79 vir die visuele ernstigheidsgraad waarde, en 0.8 vir die semi-kwantitatiewe beoordeling gelei. Statisties was daar geen verskil tussen die globale visuele indruk, die visuele ernstigheidsgraad waarde, en die semi-kwantitatiewe beoordeling nie. Ooreenstemmingsanalise tussen die EFET patroon en kliniese siektepatrone het 'n ooreenstemming van 91.6% in die diffuse patroon getoon, terwyl die fokale patroon ooreenstemming van slegs 42.8% getoon het. Bespreking en Gevolgtrekkig: In hierdie studie is gevind dat brein EFET 'n diagnose van NPSLE kan maak met 'n hoë sensitiwiteit en gemiddelde spesifisiteit. Die globale visuele indruk, visuele ernstigheidsgraad waarde, en die semi-kwantitatiewe beoordeling wat beskryf is, het geen betekenisvolle verskille tussen die tegnieke getoon nie. Die gebruik van die semi-kwantitatiewe beoordeling wat beskryf is, mag van waarde wees in sentra met beperkte ondervinding in the interpretasie van brein EFET. Die korrelasie tussen die EFET patroon en kliniese siektepatrone mag insig gee in die patofisiologie van NPSLE.