A Research Report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Medicine In the branch of Nuclear Medicine Johannesburg September 2013 / The use of Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI), with Technetium – 99m (Tc-99m) Sestamibi in conjunction with either exercise, pharmacologic stress or both is an established tool for both the diagnosis and prognostication of patients with ischemic heart disease. For perfusion imaging with SPECT, Tc-99m labeled radiopharmaceuticals (Sestamibi or Tetrofosmin) are commonly used. The major metabolic pathway for clearance of Sestamibi is the hepatobiliary system which creates difficulty in both visual and quantitative interpretation of myocardial perfusion, particularly of the inferior and infero-septal walls after reconstruction. Diluted lemon juice, an acid-rich drink is an alimentary cholekinetic that facilitates Sestamibi transit through the liver. Whole milk stimulates liver clearance as well as increases peristaltic movement. The aim of the study was to determine which protocol would be the best to reduce interfering infra-cardiac activity and therefore result in an improvement in image quality. We had three groups, comparing the use of full fat milk, diluted lemon juice and a control group that had no intervention. All patients referred to our institution for MPI from November 2009 to May 2012 were enrolled in the study. A total of six hundred and thirty (630) patients who fulfilled the inclusion criteria were randomized without stratification into three groups. Group 0 (G0) were given diluted lemon juice, 246 patients; full fat milk to group 1 (G1), 313 patients and group 2 (G2); 71 patients, had no intervention. The latter was the control group. Raw data of both the stress and rest images were visually and quantitatively assessed by two Nuclear Medicine physicians for the presence of infra-cardiac activity. The physicians were blinded to the intervention received and the data were reviewed simultaneously. The administration of milk or lemon juice resulted in a significant decrease in the intensity of infra-cardiac activity compared to the control group. This improvement was even more significant in the milk group for patients done during rest myocardial perfusion imaging.

No description available.

Heart disease is a major cause of morbidity and mortality in the United States with coronary artery disease (CAD) representing more than half of all cardiovascular events. Stable patients presenting with symptoms suggestive of CAD are likely to undergo either an exercise ECG and/or imaging study as a first line diagnostic assessment. A cardiopulmonary exercise test (CPX) is an ECG stress test plus ventilatory gas analysis. Recently CPX has been used to detect exercise-induced myocardial ischemia suggestive of underlying CAD. Currently there are a number of diagnostic tests available for the identification of CAD with the most widely used being exercise ECG, myocardial perfusion imaging (MPI) and cardiac catheterization. Exercise ECG, although inexpensive, has a number of well-recognized limitations, including low sensitivity resulting in false positive results. MPI and catheterization are more accurate but also more invasive and expensive. It appears that CPX may improve the diagnostic accuracy of exercise ECG in a cost effective manner.

A research report submitted to the Faculty of Health Sciences in fulfilment of the requirements for the degree of Master of Medicine, in Internal Medicine at the University of Witwatersrand, Johannesburg. September 2017 / Differentiating ischaemic left ventricular dysfunction (ILVD) from non-ischaemic left ventricular dysfunction (NILVD) is crucial since appropriately selected patients may benefit from coronary revascularisation. The aim of this study was to evaluate the diagnostic utility of myocardial perfusion imaging (MPI) in patients presenting with left ventricular dysfunction using coronary angiography (CA) as the gold standard. Methods This single centre retrospective study was conducted in 52 patients with heart failure with a reduced ejection fraction (EF< 40%) who had both MPI as well as CA at CHBAH between January 2005 and December 2012. ILVD was diagnosed when the distribution and severity of coronary disease on CA was sufficient to account for the degree of left ventricular dysfunction. Results From a total of 52 patients, 33 (63%) had ILVD and 19 (37%) had NILVD. As compared to patients with NILVD, those with ILVD were more likely to be Indian and White (p=0.0014), have more coronary risk factors (5(2) vs 3(2), p < 0.0001) and more commonly have q waves on the ECG (0% vs 55%, p < 0.0001). MPI had a sensitivity of 100% (95% CI 66-100%) and specificity of 52.63% (95% CI 30.18 - 75.08) for the diagnosis of ILVD. The presence of fixed perfusion defects on MPI was the best predictor of ILVD. Conclusion MPI has high sensitivity but low specificity for the diagnosis of ILVD. This makes it a useful screening test for the exclusion of coronary artery disease in patients presenting with heart failure. / MT2018

Fundamento: Distúrbios da perfusão miocárdica (DPM) é um achado comum na cardiomiopatia chagásica crônica (CCC), mas não é claro se essas alterações podem preceder a progressão da disfunção sistólica e da lesão tecidual fibrosante do ventrículo esquerdo (VE). Nós investigamos a evolução temporal das alterações da perfusão miocárdica e suas correlações com a disfunção sistólica e histopatologia do VE em um modelo experimental de CCC. Métodos: Foram estudados Hamsters sírios fêmeas (n=40) infectados com 3,5x104 formas tripomastigotas sanguíneas de T. cruzi (cepa Y) e seus respectivos controles (n=12). Os animais sobreviventes (controles, n= 10; infectados, n= 22) foram submetidos aos exames de imagem in vivo 2, 4, 6, 8 e 10 meses após a infecção. SPECT de alta resolução com 99mTcsestamibi foi utilizada para avaliar o tamanho do DPM pela construção de mapas polares considerando como limiar de captação as contagens abaixo de 50% em relação ao pixel de máxima contagem. A função e morfologia do VE foram avaliadas pelo ecocardiograma-2D. As medidas obtidas foram a fração de ejeção (FEVE) e os diâmetros sistólico e diastólico do ventrículo esquerdo (DSVE e DDVE). Os animais foram submetidos a imagens de PET para avaliação de viabilidade e inflamação miocárdica com 18F-FDG 10 meses após infecção. As imagens de PET foram co-registradas com as imagens de SPECT. A análise histopatológica incluiu a quantificação da intensidade de inflamação e da extensão de fibrose. A avaliação das diferenças entre os dois grupos ao longo do tempo foi realizada por meio da análise de variância (ANOVA) para modelos mistos de medidas repetidas. Adicionalmente, foi realizada uma análise de variância (ANOVA) considerando animais controles e dois subgrupos de animais infectados (com e sem disfunção do VE). Resultados: Na análise de variância para modelos mistos, não foi observada diferença significativa no comportamento da FEVE entre os grupos ao longo do tempo (valor-p da interação grupos#tempo= 0,06). Houve aumento progressivo do DSVE (valor-p da interação grupos#tempo< 0,001), do DDVE (valor-p da interação grupos#tempo< 0,001) e dos DPM (valor-p da interação grupos#tempo= 0,03) nos animais infectados com a diferença nessas variáveis sendo observada a partir de 8m pós-infecção. Dos animais infectados sobreviventes até o final do estudo, 8 de 22 (36%) apresentaram queda significativa da FEVE após 8 (%; 60±11 vs 70±3 vs 70±5, p=0,007) e 10 (%; 54±9 vs 70±3 vs 70±3, p<0,0001) meses de infecção quando comparados aos animais controles e animais infectados sem disfunção sistólica do VE, respectivamente. Entretanto, nesse subgrupo de animais, a deterioração da perfusão foi significativa a partir de 6 meses de infecção. Os DPM em fases mais precoces se correlacionaram com a FEVE, com os diâmetros do VE tardios e com a fibrose miocárdica. Além disso, o DPM no 6º mês se correlacionou com queda da FEVE do 6º para o 10º mês após infecção (r= 0,56, p=0,0008). DPM ocorreram em frequência e topografia comparável a doença humana, em regiões de miocárdio viável e topograficamente correlacionados com maior captação regional de 18F-FDG sugerindo correlação entre a inflamação e a deterioração da perfusão miocárdica, confirmada pelo estudo histológico.Conclusão: Defeitos de perfusão em repouso precede o desenvolvimento e se correlaciona com a deterioração ulterior da disfunção sistólica e da lesão tecidual do VE na CCC experimental. DPM foi topograficamente associado a captação elevada de 18F-FDG sugerindo correlação entre a inflamação e a deterioração da perfusão miocárdica. Nossos resultados sugerem que DPM pode ser um marcador substituto de inflamação miocárdica na CCC levantando a possibilidade da utilização de imagens de perfusão na estratificação de risco e monitorização da evolução dessa doença miocárdica. / Background: Myocardial perfusion defects (MPD) is a common finding in Chronic Chagas cardiomyopathy (CCC), but it is unclear if the perfusion late derangement can precede the left ventricular (LV) systolic dysfunction and fibrosis. We investigated the time-course of myocardial perfusion changes and the correlation with the histology and the progression of LV systolic dysfunction in an experimental model of CCC. Methods: The study included 40 female Syrian hamsters infected with 3.5x104 trypomastigotes forms of T. cruzi Y-strain and their respective controls (n=10). Surviving animals (22 infected and 10 controls) were submitted to in vivo imaging 2, 4, 6, 8 and 10- months afterwards. Rest high-resolution SPECT imaging using 99mTc-sestamibi was used to assess MPD extension that was analyzed by using polar maps considering the threshold <50% uptake compared to the maximum. The left ventricular ejection fraction (LVEF) and the systolic and diastolic diameter (LVSD and LVDD) were assessed by using 2Dechocardiogram. The animals underwent PET imaging using 18F-FDG for assessment of myocardial viability and inflammation. Histological analysis included quantification of myocardial inflammation intensity and fibrosis extension. Two way ANOVA was used for mixed models of repeated measured between two groups over the time. Additionally, one way ANOVA was used for three groups regarding the myocardial involvement within infected animals. Results: The two way ANOVA did not reveal difference in the LVEF between the groups over the time (p-value of interaction groups#time= 0.06). LVSD, LVDD and MPD presented progressive increase in infected animals (p-value of interaction groups#time< 0.05) and the differences were observed from 8 months after infection. Eight out of 22 (36%) surviving infected animals showed significant LV ejection fraction (LVEF) deterioration after 8-months (%; 60±11 vs 70±3 vs 70±5, p=0.007) and 10-months (%; 54±9 vs 70±3 vs 70±3, p<0.0001) compared to control and infected animals without systolic disfunction, respectively. However, MPD in infected animals showing LV systolic disfunction displayed significant progressive deterioration 6 monts after infection. Early stages of MPD correlated with the late values of LVEF, LVSD, LVDD and myocardial fibrosis. Moreover, MPD at 6-months correlated with the LVEF decrease from 6 to 10 months after infection (r= 0,56, p=0,0008). MPD exhibited frequency and topographic similarities with human CCC. Also, MPD correspond to metabolically viable myocardium and correlates topographically with higher 18F-FDG uptake suggesting MPD due to myocardial inflammation which was confirmed by histologic analysis. Conclusions: Rest MPD precedes the development and correlates with the ulterior fibrosis and deterioration of LV systolic dysfunction in experimental CCC. The MPD was topographically associated with elevated 18F-FDG uptake, suggesting a correlation between inflammation and the myocardial perfusion derangement. Our findings suggest that MPD maybe a surrogated marker of myocardial inflammation in CCC and raise the possibility of using perfusion imaging for risk stratification and monitoring the course of this myocardial disease.

Fundamento: Distúrbios da perfusão miocárdica (DPM) é um achado comum na cardiomiopatia chagásica crônica (CCC), mas não é claro se essas alterações podem preceder a progressão da disfunção sistólica e da lesão tecidual fibrosante do ventrículo esquerdo (VE). Nós investigamos a evolução temporal das alterações da perfusão miocárdica e suas correlações com a disfunção sistólica e histopatologia do VE em um modelo experimental de CCC. Métodos: Foram estudados Hamsters sírios fêmeas (n=40) infectados com 3,5x104 formas tripomastigotas sanguíneas de T. cruzi (cepa Y) e seus respectivos controles (n=12). Os animais sobreviventes (controles, n= 10; infectados, n= 22) foram submetidos aos exames de imagem in vivo 2, 4, 6, 8 e 10 meses após a infecção. SPECT de alta resolução com 99mTcsestamibi foi utilizada para avaliar o tamanho do DPM pela construção de mapas polares considerando como limiar de captação as contagens abaixo de 50% em relação ao pixel de máxima contagem. A função e morfologia do VE foram avaliadas pelo ecocardiograma-2D. As medidas obtidas foram a fração de ejeção (FEVE) e os diâmetros sistólico e diastólico do ventrículo esquerdo (DSVE e DDVE). Os animais foram submetidos a imagens de PET para avaliação de viabilidade e inflamação miocárdica com 18F-FDG 10 meses após infecção. As imagens de PET foram co-registradas com as imagens de SPECT. A análise histopatológica incluiu a quantificação da intensidade de inflamação e da extensão de fibrose. A avaliação das diferenças entre os dois grupos ao longo do tempo foi realizada por meio da análise de variância (ANOVA) para modelos mistos de medidas repetidas. Adicionalmente, foi realizada uma análise de variância (ANOVA) considerando animais controles e dois subgrupos de animais infectados (com e sem disfunção do VE). Resultados: Na análise de variância para modelos mistos, não foi observada diferença significativa no comportamento da FEVE entre os grupos ao longo do tempo (valor-p da interação grupos#tempo= 0,06). Houve aumento progressivo do DSVE (valor-p da interação grupos#tempo< 0,001), do DDVE (valor-p da interação grupos#tempo< 0,001) e dos DPM (valor-p da interação grupos#tempo= 0,03) nos animais infectados com a diferença nessas variáveis sendo observada a partir de 8m pós-infecção. Dos animais infectados sobreviventes até o final do estudo, 8 de 22 (36%) apresentaram queda significativa da FEVE após 8 (%; 60±11 vs 70±3 vs 70±5, p=0,007) e 10 (%; 54±9 vs 70±3 vs 70±3, p<0,0001) meses de infecção quando comparados aos animais controles e animais infectados sem disfunção sistólica do VE, respectivamente. Entretanto, nesse subgrupo de animais, a deterioração da perfusão foi significativa a partir de 6 meses de infecção. Os DPM em fases mais precoces se correlacionaram com a FEVE, com os diâmetros do VE tardios e com a fibrose miocárdica. Além disso, o DPM no 6º mês se correlacionou com queda da FEVE do 6º para o 10º mês após infecção (r= 0,56, p=0,0008). DPM ocorreram em frequência e topografia comparável a doença humana, em regiões de miocárdio viável e topograficamente correlacionados com maior captação regional de 18F-FDG sugerindo correlação entre a inflamação e a deterioração da perfusão miocárdica, confirmada pelo estudo histológico.Conclusão: Defeitos de perfusão em repouso precede o desenvolvimento e se correlaciona com a deterioração ulterior da disfunção sistólica e da lesão tecidual do VE na CCC experimental. DPM foi topograficamente associado a captação elevada de 18F-FDG sugerindo correlação entre a inflamação e a deterioração da perfusão miocárdica. Nossos resultados sugerem que DPM pode ser um marcador substituto de inflamação miocárdica na CCC levantando a possibilidade da utilização de imagens de perfusão na estratificação de risco e monitorização da evolução dessa doença miocárdica. / Background: Myocardial perfusion defects (MPD) is a common finding in Chronic Chagas cardiomyopathy (CCC), but it is unclear if the perfusion late derangement can precede the left ventricular (LV) systolic dysfunction and fibrosis. We investigated the time-course of myocardial perfusion changes and the correlation with the histology and the progression of LV systolic dysfunction in an experimental model of CCC. Methods: The study included 40 female Syrian hamsters infected with 3.5x104 trypomastigotes forms of T. cruzi Y-strain and their respective controls (n=10). Surviving animals (22 infected and 10 controls) were submitted to in vivo imaging 2, 4, 6, 8 and 10- months afterwards. Rest high-resolution SPECT imaging using 99mTc-sestamibi was used to assess MPD extension that was analyzed by using polar maps considering the threshold <50% uptake compared to the maximum. The left ventricular ejection fraction (LVEF) and the systolic and diastolic diameter (LVSD and LVDD) were assessed by using 2Dechocardiogram. The animals underwent PET imaging using 18F-FDG for assessment of myocardial viability and inflammation. Histological analysis included quantification of myocardial inflammation intensity and fibrosis extension. Two way ANOVA was used for mixed models of repeated measured between two groups over the time. Additionally, one way ANOVA was used for three groups regarding the myocardial involvement within infected animals. Results: The two way ANOVA did not reveal difference in the LVEF between the groups over the time (p-value of interaction groups#time= 0.06). LVSD, LVDD and MPD presented progressive increase in infected animals (p-value of interaction groups#time< 0.05) and the differences were observed from 8 months after infection. Eight out of 22 (36%) surviving infected animals showed significant LV ejection fraction (LVEF) deterioration after 8-months (%; 60±11 vs 70±3 vs 70±5, p=0.007) and 10-months (%; 54±9 vs 70±3 vs 70±3, p<0.0001) compared to control and infected animals without systolic disfunction, respectively. However, MPD in infected animals showing LV systolic disfunction displayed significant progressive deterioration 6 monts after infection. Early stages of MPD correlated with the late values of LVEF, LVSD, LVDD and myocardial fibrosis. Moreover, MPD at 6-months correlated with the LVEF decrease from 6 to 10 months after infection (r= 0,56, p=0,0008). MPD exhibited frequency and topographic similarities with human CCC. Also, MPD correspond to metabolically viable myocardium and correlates topographically with higher 18F-FDG uptake suggesting MPD due to myocardial inflammation which was confirmed by histologic analysis. Conclusions: Rest MPD precedes the development and correlates with the ulterior fibrosis and deterioration of LV systolic dysfunction in experimental CCC. The MPD was topographically associated with elevated 18F-FDG uptake, suggesting a correlation between inflammation and the myocardial perfusion derangement. Our findings suggest that MPD maybe a surrogated marker of myocardial inflammation in CCC and raise the possibility of using perfusion imaging for risk stratification and monitoring the course of this myocardial disease.

Purpose: To evaluate the diagnostic performance of Coronary Computed Tomography Angiography (CCTA) in predicting Myocardial Perfusion Scintigraphy (MPS) perfusion defects in low likelihood patients with End Stage Renal Disease (ESRD) awaiting transplant. Materials and Methods: In total, 131 consecutive patients with ESRD awaiting transplant were prospectively enrolled in this study (86 men; 54±9years). All patients underwent MPS as per standard of care and in addition non-enhanced CT for calcium scoring (CAC score) and Coronary Computed Tomography Angiography (CCTA). Results: The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CAC score in predicting MPS perfusion defects were 88%, 35%, 28% and 92%, respectively. The sensitivity, specificity, PPV and NPV of CCTA in predicting MPS perfusion defects at the patient level were 55%, 87%, 57% and 87%, respectively, and 48%, 92%, 41% and 94% at the vessel level. The diagnostic performance of CCTA in predicting MPS perfusion defects improved when patients with CAC score higher than 1000 (15/70, 21%) were excluded from the analysis. In patients with positive CAC score up to 1000 sensitivity, specificity, PPV and NPV at the patient level were 60%, 93%, 75% and 86% respectively. These were 53%, 91%, 36% and 95%, respectively, at the vessel level. Conclusion: Non-enhanced CT for CAC score and CCTA can be considered useful diagnostic tools in the ESRD population, particularly in identifying patients without coronary artery disease. This approach however had limitations in the presence of high CAC score.

The assessment of Myocardial Blood Flow (MBF) is an important measure in clinical practice for evaluating the health of the heart. Multiple imaging methods have been employed to measure MBF, including applications of nuclear medicine, x-ray and contrast enhanced Magnetic Resonance Imaging (MRI). However, each of these modalities suffers from drawbacks, such as invasiveness due to radiation or intravenous contrast injection, difficulty in quantitation, and limited repeatability. The aim of this thesis was to develop a non-invasive, quantitative and repeatable MRI method for the measurement of MBF, by applying the techniques of Arterial Spin Labelling (ASL). A novel cardiac ASL sequence was designed and thoroughly tested by simulation and phantom experiment. The method was applied in vivo in three slices of the human heart, to our knowledge the first cardiac ASL acquisition in multiple slices, in ten healthy volunteers. The resulting values of mid-ventricular MBF, averaged over multiple measurements, compared well with the literature values from multiple modalities. Repeat measures were then used in order to characterise the reproducibility and variation inherent in the method, showing that the expected change in MBF would be detectable with the ASL sequence. Segmental values of MBF, according to the AHA standard model, were also calculated and these compared well to previous PET literature. This work has been published in the journal Magnetic Resonance in Medicine. Further to this work, the new cardiac ASL sequence was optimised with the ultimate goal of single breath hold acquisitions. The optimised sequence was shown to improve the results in terms of the balance between good signal-to-noise ratio and reducing spatial and temporal variation in MBF values. Though improvements were made, there remained a large variation in the measured values of MBF, meaning single breath hold acquisition in a clinical context is not yet practical. In addition to the optimisation, the online scanner reconstruction software was altered to produce parametric maps of both T₁ and MBF direct to the scanner operator. The sequence, along with online reconstruction is available for use in our laboratory for future clinical trials in the heart and liver.

Computed tomography imaging has revolutionised modern medicine and we can now study the body in greater detail than ever before. Cardiac computed tomography has the potential to provide information not just on coronary anatomy, but also on myocardial function, perfusion and viability. This thesis addresses the optimisation and validation of computed tomography imaging of the heart using a wide volume 320-multidetector scanner. Computed tomography coronary angiography now has diagnostic accuracy comparable to invasive coronary angiography. However, radiation dose remains an important concern. It is therefore important to minimise computed tomography radiation dose while maintaining image quality. I was able to demonstrate that iterative reconstruction and patient tailored imaging techniques led to a 39% reduction in radiation dose in computed tomography coronary angiography, while maintaining subjective and objective assessments of image quality. In addition, I demonstrated that diagnostic images can be obtained in 99% of unselected patients presenting with suspected coronary artery disease when using single heart-beat 320- multidetector computed tomography coronary angiography. Computed tomography myocardial perfusion imaging can provide additional and complementary information as compared to computed tomography coronary angiography that can aid diagnosis and management. I established both quantitative and qualitative assessment of computed tomography myocardial perfusion imaging and validated it against both a clinical “gold-standard”, fractional flow reserve during invasive coronary angiography, and a physiological “gold-standard”, positron emission tomography with oxygen-15 labelled water. Finally, I was able to show that techniques to reduce radiation dose can also be applied to computed tomography myocardial perfusion imaging, leading to a 60% reduction in radiation dose, while maintaining image quality. In my thesis, I have established that comprehensive cardiac angiographic and perfusion imaging can be performed with wide volume computed tomography in a broad generalizable population of patients with relatively low radiation exposure. These techniques provide both structural and functional assessments from a single imaging modality that are valid and readily applicable to the clinic in the assessment and management of patients with suspected coronary artery disease.

A angiografia coronariana por tomografia computadorizada (ACTC) é um exame bem estabelecido no diagnóstico da doença arterial coronariana. Entretanto, segmentos coronarianos submetidos a implante de stent podem apresentar limitação na avaliação luminal. O objetivo deste estudo é avaliar o valor adicional da perfusão miocárdica por tomografia computadorizada (PMTC) à avaliação anatômica isolada pela ACTC em portadores de stent, tendo o cateterismo (CATE) como referência. Quarenta e seis pacientes (56,9±7,2 anos, 28 homens) com indicação clínica de CATE em até 60 dias foram submetidos à avaliação combinada de ACTC e PMTC, por meio de tomógrafo de 64 detectores (Aquillion 64, Toshiba). A aquisição foi iniciada com a fase de estresse (PMTC) usando-se dipiridamol a 0,56mg/kg/4min e 60ml de contraste a 3ml/s, seguido de reversão com aminofilina 240mg e metoprolol (até 20mg). Em seguida, realizou-se a ACTC com 80-90ml de constraste a 5ml/s. Os dados da PMTC, da ACTC, e do CATE foram analisados por dois observadores independentes, sem informações clínicas dos pacientes. Primariamente analisou-se a ACTC, seguida da avaliação da PMTC. Concluída esta fase, os observadores tinham a possibilidade de reclassificar os segmentos coronarianos submetidos a stent cuja avaliação estivesse limitada ou inadequada por artefatos. A dose total média de radiação foi 15,83±4,93 mSv e todos os exames foram adequados. Um total de 129 segmentos coronarianos foi avaliado na ACTC, bem como os respectivos territórios miocárdicos pela PMTC. Destes, 54 territórios (42%) eram relacionados à presença de stents, sendo 19 com stents de avaliação adequada e 23 com avaliação luminal limitada, porém possível, e 12 segmentos de avaliação inadequada (sem possibilidade de avaliação luminal). Os valores de sensibilidade, especificidade, valor preditivo positivo, valor preditivo negativo e acurácia para a ACTC isolada nos territórios com stents foram de, respectivamente: 85%, 76%, 85%, 76% e 81%, e com o uso combinado da ACTC + PMTC foram de, respectivamente 88%, 95%, 97%, 83% e 92% (p=0,0314). Nos territórios com stent e avaliação luminal prejudicada (limitada ou inadequada) os valores para análise da ACTC isolada foram de, respectivamente: 83%, 71%, 75%, 80% e 77% e após a análise da ACTC + PMTC foram de, respectivamente: 89%, 94%, 94%, 89% e 92% (p = 0,0441). A avaliação combinada da ACTC + PMTC permitiu melhorar a acurácia diagnóstica da avaliação de obstrução coronariana significativa em pacientes portadores de stents, comparativamente à avaliação isolada da ACTC / Coronary computed tomography angiography (coronary CTA) is a well established examination in the diagnosis of coronary artery disease (CAD). However, the segments with prior coronary stent implantation may have limited luminal evaluation. The aim of this study is to assess the incremental value of myocardial computed tomography perfusion (myocardial CTP) to the anatomical assessment by coronary CTA alone in patients with stents, using catheterization (CAT) as a reference method. Forty-six patients (56.9 ± 7.2 years, 28 men) referred to CAT by clinical indication within 60 days, were evaluated with combined evaluation of coronary CTA and myocardial CTP through 64-detector CT scanner (Aquillion 64, Toshiba). The acquisition protocol began with the stress phase (myocardial CTP), using dipyridamole to 0.56 mg/kg/4min and 60ml of contrast (3ml/s), followed by a bolus of aminophylline 240 mg and metoprolol (up to 20mg). After, it was performed the coronary CTA wih 80-90ml of contrast (5 ml/s). Data from the myocardial CTP, coronary CTA and CAT were analyzed by two independent observers, with no knowledge to clinical information. The observers reviewed the coronary CTA findings, and in a second time performed the evaluation of myocardial CTP. So, they had the possibility to reclassify segments with coronary stent that were considered with limited or inadequate assessment due to artifacts. Mean total dose of radiation was 15.83 ± 4.93 mSv, and all examinations were interpretable. A total of 129 coronary segments were evaluated by coronary CTA, and also were their correspondent myocardial territories by myocardial CTP. Of these, 54 territories (42%) were related to the presence of stents, 19 stents with adequate evaluation, 23 with limited evaluation, but possible, and 12 with inadequate evaluation (no luminal assessment possible). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the coronary CTA in territories with stents were respectively: 85%, 76%, 85%, 76% and 81%, and the combined use of coronary CTA + Myocardial CTP were respectively 88%, 95%, 97%, 83% and 92% (p=0.0314). In territories with impaired luminal stent evaluation (limited or inadequate), the values for analysis of coronary CTA alone were: 83%, 71%, 75%, 80% and 77%, and after analysis of myocardial CTP were, respectively: 89%, 94%, 94%, 89% and 92% (p = 0.0441). The combined evaluation of the coronary CTA and myocardial CTP has improved the diagnostic accuracy of the evaluation of significant coronary obstruction in patients with stents, compared to the assessment of coronary CTA alone