RESUMO
Based on first-principles calculations, we prove that the origin of charge-density wave formation in metallic layered transition metal dichalcogenides (TMDC) is not due to an electronic effect, like the Fermi surface (FS) nesting, as it had been proposed. In particular, we consider NbSe2, NbS2, TaSe2, and TaS2 as representative examples of 2H-TMDC polytypes. Our main result consists that explicit inclusion of the matrix elements in first-principles calculations of the electron susceptibility [Formula: see text] removes, due to strong momentum dependence of the matrix elements, almost all the information about the FS topologies in the resulting [Formula: see text]. This finding strongly supports an interpretation in which the momentum dependence of the electron-phonon interaction is the only reason why the phenomenon of charge-density waves appears in this class of materials.
RESUMO
Different methods to calculate (90)Y resin microspheres activity for Selective Internal Radiation Therapy (SIRT) were compared. Such comparison is not yet available and is needed in clinical practice to optimize patient specific treatment planning. 32 (99m)Tc-macroagregates (MAA) evaluations were performed, followed by 26 treatments. Four methods to calculate (90)Y-activity were applied retrospectively: three based on Body Surface Area and one based on MIRD formalism, partition model (PM). Relationships between calculated activities, lung breakthrough (LB), the activity concentration ratio between lesions and healthy liver (T/N) and tumour involvement were investigated, where lobar and whole liver treatments were analysed separately. Without attenuation correction, overestimation of LB was 65%. In any case, the estimated lungs' doses remained below 30 Gy. Thus, the maximal injectable activity (MIA) is not limited by lungs' irradiation. Moreover, LB was not significantly related to T/N, neither to tumour involvement nor radiochemical purity (RP). Differences in calculated activity with the four methods were extremely large, in particular they were greater between BSA-based and PM activities for lobar treatments (from -85% to 417%) compared to whole liver treatments (from -49% to 61%). Two values of T/N ratio were identified as thresholds: for BSA-based methods, healthy liver doses are much higher than 30 Gy when T/N < 3; for PM, tumour doses are higher than 120 Gy when T/N > 4. As PM accounts for uptake ratio between normal and tumour liver, this method should be employed over BSA-based methods.
Assuntos
Fígado/efeitos da radiação , Microesferas , Planejamento da Radioterapia Assistida por Computador/métodos , Superfície Corporal , Humanos , Neoplasias Hepáticas/radioterapia , Pulmão/efeitos da radiação , Especificidade de Órgãos , Doses de Radiação , Dosagem Radioterapêutica , Radioisótopos de Ítrio/química , Radioisótopos de Ítrio/uso terapêuticoRESUMO
We studied the potential use of [(18) F]fluorodeoxyglucose ((18) F-FDG) whole body positron emission tomography (PET)-computed tomography for the diagnosis of device infection and extension of infection. Twenty-one patients with suspected device infection were prospectively included and compared with 14 controls free of infection. (18) F-FDG uptake on the box and on the leads was visually and quantitatively interpreted (using the maximal standard uptake value). The final diagnosis was obtained either from bacteriological data after device culture (n = 11) or by a 6-month follow-up according to modified Duke's criteria (n = 10). Ten patients finally showed infection on bacteriological study (n = 8) or during follow-up (n = 2). Sensitivity, specificity, positive predictive value and negative predictive value were, respectively, 80%, 100%, 100% and 84.6% on patient-based analysis (presence or absence of infection). They were 100%, 100%, 100% and 100% for boxes, but only 60%, 100%, 100% and 73% for leads. Quantitative analysis could be useful for boxes but not for leads, for which the presence of a mild hot spot was the best criterion of infection. The four false negatives on leads received antibiotics for longer than the six true positives (20 ± 7.2 vs. 3.2 ± 2.3 days, p <0.01). Although the study was not designed for this purpose, management could have been modified by PET results in six of 21 patients. (18) F-FDG PET imaging may be useful for the diagnosis of device infection, and could impact on clinical management. Interpretation of negative cases should be performed with caution if patients have received antibiotics.
Assuntos
Infecções Bacterianas/diagnóstico , Desfibriladores Implantáveis/efeitos adversos , Fluordesoxiglucose F18/administração & dosagem , Tomografia por Emissão de Pósitrons/métodos , Complicações Pós-Operatórias/diagnóstico , Imagem Corporal Total/métodos , Bactérias/isolamento & purificação , Infecções Bacterianas/patologia , Erros de Diagnóstico , Humanos , Complicações Pós-Operatórias/patologia , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e EspecificidadeRESUMO
Optimal staging and evaluation of residual lesions of invasive fungal infections (IFIs) are major challenges in the immunocompromised host. Preliminary data have suggested that [¹8F]fluorodeoxyglucose ([¹8F]FDG) uptake may be observed in the course of active invasive fungal infections. The aim of this study was to assess the role of positron emission tomography with [¹8F]FDG ([¹8F]FDG-PET) in the diagnosis and staging of IFI. A prospective monocentric study evaluating [¹8F]FDG-PET in 30 consecutive adults and children with European Organization for Research and Treatment of Cancer/Mycoses Study Group probable or proven IFI was performed. Twenty males and ten females (median age, 45 years (range 6-7 years)) were enrolled. Twenty-six were immunocompromised, as follows: haematological malignancy (18) with allogeneic stem cell transplantation (16/18), solid tumour (three), solid organ transplantation (two), diabetes mellitus (two) and cystic fibrosis (one). IFIs were acute invasive aspergillosis (ten), chronic disseminated candidiasis (ten), zygomycosis (two), black grains eumycetoma (two), pulmonary Histoplasma capsulatum var. capsulatum histoplasmosis (two), and Phomopsis sp. osteoarthritis, Scedosporium apiospermum and Candida krusei spondylodiscitis, and acute pulmonary coccidioidomycosis in one case each. An increased uptake of [¹8F]FDG was observed in all areas previously identified by computed tomography and/or magnetic resonance imaging to be involved by IFI. In 4/10 chronic disseminated candidiasis cases, [¹8F]FDG-PET revealed small splenic abscesses that were unapparent on the corresponding computed tomography scan. [¹8F]FDG uptake disappeared after 6 months of antifungal therapy in three patients with chronic disseminated candidiasis for whom the [¹8F]FDG-PET was performed to assess the evolution of the disease. [¹8F]FDG-PET could potentially be useful for the initial diagnosis and staging of IFI. Whether or not [¹8F]FDG-PET might be useful for assessing the optimal duration of IFI therapy should now be assessed in a specific prospective study.
Assuntos
Fluordesoxiglucose F18 , Micoses/diagnóstico por imagem , Compostos Radiofarmacêuticos , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Micoses/patologia , Tomografia por Emissão de Pósitrons , Estudos Prospectivos , Imagem Corporal Total , Adulto JovemRESUMO
F-18 fluorodeoxyglucose positron emission tomography is now part of the initial stage III and IV cancer work-up and each time that metastasis or the presence of a second cancer is suspected that may contraindicate major surgery. Similarly, this exam should be undertaken when the conventional work-up is negative but there is isolated metastatic adenopathy. In therapeutic follow-up, a 3- or 4-month delay must be respected to prevent false-positive exams caused by inflammation. Although FDG-PET seems very promising in determining target volumes in radiotherapy, its implementation raises a number of problems that can only be resolved through the collaboration of all of the different specialists.
Assuntos
Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Neoplasias Otorrinolaringológicas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Adulto , Fluordesoxiglucose F18 , Humanos , Metástase Linfática/diagnóstico por imagem , Metástase Linfática/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Segunda Neoplasia Primária/diagnóstico por imagem , Segunda Neoplasia Primária/patologia , Segunda Neoplasia Primária/radioterapia , Segunda Neoplasia Primária/cirurgia , Neoplasias Otorrinolaringológicas/patologia , Neoplasias Otorrinolaringológicas/radioterapia , Neoplasias Otorrinolaringológicas/cirurgia , Planejamento da Radioterapia Assistida por Computador , Resultado do TratamentoRESUMO
We report the case of a carcinoid tumor with suspicion of recurrence on biology. Scintigraphic explorations of the whole body had a major role in diagnostic of this recurrence. OctreoScan((R)) showed an abdominal uptake corresponding to a mesenteric lymph node. PET with (18)F-DOPA also showed a liver uptake corresponding to liver metastases.
Assuntos
Tumor Carcinoide/diagnóstico por imagem , Neoplasias do Colo/diagnóstico por imagem , Di-Hidroxifenilalanina/análogos & derivados , Radioisótopos de Flúor , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Peritoneais/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Biomarcadores Tumorais/sangue , Tumor Carcinoide/sangue , Tumor Carcinoide/secundário , Neoplasias do Colo/sangue , Neoplasias do Colo/patologia , Humanos , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Recidiva Local de Neoplasia/diagnóstico por imagem , Neoplasias Peritoneais/sangue , Neoplasias Peritoneais/secundário , Tomografia por Emissão de Pósitrons/métodos , Valor Preditivo dos Testes , Sensibilidade e EspecificidadeRESUMO
OBJECTIVES: To evaluate detection rate, topography and false negatives of sentinel lymph node in endometrial cancer. MATERIAL AND METHODS: Twenty-six patients were included. Lymphoscintigraphy was performed the day before surgery. Preoperative detection of the sentinel lymph node was performed with cervical blue dye injection and a gamma probe. Separate pathology examinations were performed for sentinel and non-sentinel lymph nodes. Sentinel lymph nodes were examined with hematoxylin-eosin-safran stain, and immunohistochemistry if negative. RESULTS: Twenty-six patients had a positive lymphoscintigraphy. Preoperative detection was successful in 21 patients (80.8%): the detection rate with isotopic method, 19 cases (73.1%), was superior to the dye detection, 15 cases (57.7%). No isolated lombo-aortic sentinel lymph nodes were observed, and all sentinel lymph nodes were in the ilio-obturator region. Seven patients presented lymphatic spread, and 4 of them had at least one sentinel node. There was one micrometastasis in sentinel node, associated with isolated tumoral cells in pelvic lymphadenectomy. There was no false negative of sentinel node. CONCLUSION: The biopsy of sentinel lymph node is a feasible procedure in endometrial cancer. There was one micrometastatic sentinel node. However there was no isolated lomboaortic sentinel lymph node in this study.
Assuntos
Neoplasias do Endométrio/patologia , Biópsia de Linfonodo Sentinela , Adenocarcinoma/patologia , Idoso , Reações Falso-Negativas , Feminino , Humanos , Imuno-Histoquímica , Excisão de Linfonodo , Linfonodos/diagnóstico por imagem , Metástase Linfática/patologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Prospectivos , CintilografiaRESUMO
OBJECTIVES: The aim of this study was to assess the diagnosis of myocarditis in patients presenting with acute myocardial infarction (MI) and normal coronary angiograms. BACKGROUND: Most often in these patients, the etiologic diagnosis remains unclear once they are found to have normal coronary arteries. The diagnosis of myocarditis mimicking MI is clinically relevant, because numerous arguments suggest a relation between myocarditis and dilated cardiomyopathy. Myocardial indium-111 (111In)-antimyosin antibody (AMA)/rest thallium-201 (201Tl) imaging allows noninvasive detection of myocarditis. METHODS: Forty-five patients admitted to three intensive care units for suspicion of acute MI, with normal coronary angiograms, were investigated. Indium-111-AMA planar images and then a dual-isotope rest AMA/201Tl tomographic study were performed. Six-month echocardiographic follow-up was obtained in 80% of the patients with initial left ventricular (LV) wall motion abnormalities. RESULTS: In eight patients, AMA and 201Tl scintigraphy were negative. In two patients, a matched 201Tl defect and focal AMA uptake suggested acute MI (due to prolonged vasospasm or spontaneously reperfused coronary occlusion). In 17 patients, diffuse AMA uptake over the whole LV suggested diffuse myocarditis. In 18 patients, focal AMA uptake with a normal 201Tl scan suggested diffuse but heterogeneous, or focal myocarditis. Complete functional recovery was observed in 81% of the patients with a pattern of myocarditis. CONCLUSIONS: Among 45 patients presenting with acute MI and normal coronary angiograms, 38% had diffuse myocarditis and 40% had a scintigraphic pattern of heterogeneous or focal myocarditis. Short-term follow-up showed complete LV functional recovery in 81% of these patients.
Assuntos
Infarto do Miocárdio/diagnóstico , Miocardite/diagnóstico , Adulto , Anticorpos Monoclonais/imunologia , Angiografia Coronária , Eletrocardiografia , Feminino , Humanos , Radioisótopos de Índio , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Miocardite/diagnóstico por imagem , Miocardite/fisiopatologia , Compostos Organometálicos/imunologia , Estudos Prospectivos , Cintilografia , Ultrassonografia , Função Ventricular EsquerdaRESUMO
UNLABELLED: A lack of specificity for myocardial perfusion imaging has been widely reported, mostly related to false-positive defects on the inferior wall. The application of depth-dependent resolution recovery (RR), attenuation correction (AC) using external source devices, and scatter correction has been proposed to resolve this pitfall. METHODS: We studied the clinical benefit of depth-dependent RR, nonuniform AC using a scanning line source, and scatter correction (photon energy recovery [PER]) compared with filtered backprojection alone. Eighty-two patients were included: 40 healthy volunteers with a low likelihood of coronary artery disease (control group) and 42 patients with proven right or circumflex coronary artery disease but without involvement of the left anterior descending artery. Among these 82 patients, the images of 33 were also processed with PER. RESULTS: RR did not alter the performance of filtered backprojection alone. AC + RR greatly improved specificity and the rate of normal (201)Tl SPECT findings in the control population (from 56% to 95% and from 53% to 100%, respectively) but significantly decreased sensitivity (from 92% to 54%). AC + RR generated a false anteroapical defect in 21% of patients and reverse redistribution of the apex in 23%. AC + RR significantly decreased the extent of the stress defect (from 4.09 to 3.21 segments, P < 0.003) and increased the perfusion score of the stress defect (from 0.78 +/- 0.72 to 1.47 +/- 1.11, P < 0.00061). Moreover, AC + RR generated overcorrection on the inferior wall, leading to false estimation of viability for 11 of 15 patients with an old inferior myocardial scar without evidence of residual viability. PER decreased overcorrection on the inferior wall, but without improving sensitivity. PER did not significantly reduce the number of anteroapical false-positives or the number of apical reverse distribution cases. CONCLUSION: AC + RR improved the specificity and normalcy rate of (201)Tl SPECT myocardial perfusion imaging but generated overcorrection on the inferior wall, leading to low sensitivity and to false evaluation of myocardial viability in 73% of the patients with inferior infarction. AC + RR also generated anteroapical artifacts. The addition of scatter correction did not significantly reduce these drawbacks.
Assuntos
Circulação Coronária , Doença das Coronárias/diagnóstico por imagem , Radioisótopos de Tálio , Tomografia Computadorizada de Emissão de Fóton Único , Dipiridamol , Teste de Esforço , Humanos , Processamento de Imagem Assistida por Computador , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Sensibilidade e EspecificidadeRESUMO
UNLABELLED: The current major limitation to development of electrocardiographically (ECG) gated blood-pool SPECT (GBPS) for measurement of the left ventricular (LV) ejection fraction (LVEF) and volumes is the lack of availability of clinically validated automatic processing software. Recently, 2 processing software methods for quantification of the LV function have been described. Their LVEFs have been validated separately, but no validation of the LV volume measurement has been reported. METHODS: We compared 3 processing methods for evaluation of the LVEF (n = 29) and volumes (n = 58) in 29 patients: automatic geometric method (GBPS(G)), semiautomatic activity method (GBPS(M)), and 35% maximal activity manual method (GBPS(35%)). The LVEF provided by the ECG gated equilibrium planar left anterior oblique view (planar(LAO)) and the LV volumes provided by LV digital angiography (Rx) were used as gold standards. RESULTS: Whereas the GBPS(G) and GBPS(M) methods present similar low percentage variabilities, the GBPS(35%) method provided the lowest percentage variabilities for the LVEF and volume measurements (P < 0.04 and P < 0.02, respectively). The LVEF and volume provided by the 3 methods were highly correlated with the gold standard methods (r > 0.98 and r > 0.83, respectively). The LVEFs provided by the GBPS(35%) and GBPS(M) methods are similar and higher than those of the GBPS(G) method and planar(LAO) method, respectively (P < 0.0001). For the LVEF, there is no correlation between the average and paired absolute difference for the 3 GBPS methods against the planar(LAO) method, and the limits of agreement are relatively large. LV volumes are lower when calculated with the GBPS(M), GBPS(G), and Rx methods (P < 0.0001). However, the GBPS(35%) and Rx methods provide LV volumes that are similar. There is no linear correlation between the average and the paired absolute difference of volumes calculated with the GBPS(G) and GBPS(35%) methods against Rx LV volumes. However, a moderate linear correlation was found with the GBPS(M) method (r = 0.6; P = 0.0001). The 95% limits of agreement between the Rx LV volumes and the 3 GBPS methods are relatively large. CONCLUSION: GBPS is a simple, highly reproducible, and accurate technique for the LVEF and volume measurement. The reported findings should be considered when comparing results of different methods (GBPS vs. planar(LAO) LVEF; GBPS vs. Rx volume) and results of different GBPS processing methods.
Assuntos
Eletrocardiografia , Imagem do Acúmulo Cardíaco de Comporta , Processamento de Imagem Assistida por Computador/métodos , Volume Sistólico , Tomografia Computadorizada de Emissão de Fóton Único , Função Ventricular Esquerda , Humanos , Masculino , Pessoa de Meia-Idade , Angiografia Cintilográfica , Processamento de Sinais Assistido por Computador , Software , Tomografia Computadorizada de Emissão de Fóton Único/métodosRESUMO
BACKGROUND: To overcome some of the limitations imposed by planar imaging, we aimed to optimize the use of first harmonic Fourier phase analysis (FPA) in electrocardiography-gated blood-pool single photon emission computed tomography (GBPS) by comparing different quantitative, 3-dimensional methods. METHODS AND RESULTS: Three groups of patients who underwent GBPS were evaluated: group 1, 8 patients with no heart disease; group 2, 10 patients with left ventricular disease; and group 3, 6 patients with right ventricular disease. Six different methods for FPA were compared: surface, cylindrical, spherical, and hybrid methods with fixed thresholding and spherical and hybrid methods with multiple thresholding. The hybrid method with multiple thresholding for the left ventricle and the spherical method for the right ventricle provided the highest discrimination score (phase) between normal and abnormal ventricles. Among methods with similar discrimination score for these 2 methods, the cylindrical and hybrid methods for the left ventricle and the spherical method for the right ventricle provided the best homogeneity of phase distribution histogram in normal ventricles. These were considered the optimal methods for FPA. CONCLUSIONS: The hybrid or cylindrical method for the left ventricle and the spherical method for the right ventricle with fixed thresholding are the optimal methods for FPA in GBPS.
Assuntos
Eletrocardiografia/métodos , Análise de Fourier , Imagem do Acúmulo Cardíaco de Comporta/métodos , Ventrículos do Coração/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Disfunção Ventricular Esquerda/diagnóstico , Disfunção Ventricular Direita/diagnóstico , HumanosRESUMO
BACKGROUND: The prognosis of patients with right ventricular (RV) arrhythmias remains uncertain. This study prospectively evaluated the prognostic value of RV and left ventricular (LV) involvement assessed by radionuclide angiography (RNA) as predictors for sudden death. METHODS AND RESULTS: Patients (n=188) with severe arrhythmias originating from the RV were followed up for a mean of 45+/-34 months. Data on clinical presentation, resting and stress ECG, signal-averaged ECG, 24-hour Holter monitoring, and programmed stimulation were collected along with RNA. Patients were classified as group I (n=82) with normal RNA or group II (n=106) with an abnormal RV suggestive of arrhythmogenic RV cardiomyopathy, classified as diffuse or localized disease, with or without associated LV abnormalities. During follow-up, 14 patients died suddenly, all in group II. None of the clinical and electrical data were predictive of death. An abnormal RNA study was a highly predictive factor for death (P<0.005), as well as the presence of LV abnormalities (P<0.01). CONCLUSIONS: The present study confirms that arrhythmogenic RV cardiomyopathy is a severe disease with a high risk for cardiac death. Evidence of RV abnormalities in patients presenting with RV arrhythmias is highly predictive for sudden death, as is its association with LV involvement.
Assuntos
Arritmias Cardíacas/diagnóstico , Angiografia Cintilográfica , Disfunção Ventricular Direita/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Arritmias Cardíacas/complicações , Morte Súbita Cardíaca/etiologia , Eletrocardiografia , Eritrócitos/metabolismo , Feminino , Seguimentos , Análise de Fourier , Humanos , Funções Verossimilhança , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Medição de Risco , Volume Sistólico , Taxa de Sobrevida , Tecnécio , Disfunção Ventricular Direita/complicaçõesRESUMO
BACKGROUND: 201Tl myocardial scintigraphy (201Tl SPECT) is of strong prognostic value in various populations with suspected or known coronary artery disease. However, its value in patients with coronary artery bypass grafting (CABG) is not fully assessed. METHODS: We examined 115 consecutive patients to determine the relation between clinical data/stress 201Tl SPECT performed 5+/-3 years after CABG, and subsequent cardiac events. RESULTS: Thirteen patients (11%) had stress-induced angina, 22 (19%) had electrical positivity, and 97 (84%) had abnormal scintigraphy, including 62 (54%) with reversible defects. During follow-up (35+/-22 months), there were nine cardiac deaths, seven myocardial infarctions, and 20 revascularization procedures. Multivariate Cox analysis identified the delay between CABG and scintigraphy (P<0.01, relative risk (RR) = 1.01), the extent of stress 201Tl defects (P = 0.04, RR = 1.18), and increased stress 201Tl lung uptake (P = 0.03, RR = 3.56) as significant predictors of cardiac deaths/infarctions. Delay between CABG and scintigraphy (P < 0.001, RR = 1.01), the extent of stress 201Tl defects (P = 0.03, RR = 1.15), and that of reversible defects (P = 0.05, RR = 1.13) were the only significant predictors of total events. CONCLUSIONS: Besides the delay between CABG and scintigraphy, the scintigraphic parameters were the only significant and additive predictors of cardiac events in 115 patients with CABG.
Assuntos
Ponte de Artéria Coronária , Coração/diagnóstico por imagem , Tálio , Adulto , Idoso , Intervalo Livre de Doença , Teste de Esforço , Feminino , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Radioisótopos de Tálio , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Electrocardiographic gated myocardial scintigraphy (gated SPECT) allows simultaneous evaluation of left ventricular perfusion and contractility. The aim of this study was to assess the impact of the type of tracer and temporal sampling on the measurement of the ejection fraction by gated SPECT. Eighty-six consecutive patients (59 men, 27 women, average age 62 +/- 11 years) with a history of myocardial infarction (anterior N = 50--inferior N = 36) were studied. All had measurement of the isotopic ejection fraction by equilibrium angioscintigraphy and by gated SPECT sampled at 8 (N = 45, 52%) or 16 images/cycle RR (N = 41, 48%). After filtered retroprojection, the ejection fraction was calculated by a validated method (QGS). A better correlation between gated SPECT and equilibrium angioscintigraphy was observed at 16 images/cycle (r = 0.90) compared with 8 (r = 0.80). The Bland-Altman curves showed improved accuracy of the measurement of the ejection fraction by gated SPECT with 16 compared with 8 images/cycles sampling (mean differences of 0.37 +/- 6.06% and 4.3 +/- 7.71%, respectively). Multivariable analysis showed that temporary sampling was the only parameter to significantly affect the difference between the two methods. There was no difference between the use of Thallium and that of 99mTc-sestamibi. Gated SPECT, therefore, provides an accurate measurement of the ejection fraction for routine clinical usage, providing the acquisition is made at 16 images/cycle.
Assuntos
Eletrocardiografia , Coração/diagnóstico por imagem , Coração/fisiopatologia , Contração Miocárdica , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Tomografia Computadorizada de Emissão de Fóton Único , Função Ventricular Esquerda/fisiologia , Feminino , Imagem do Acúmulo Cardíaco de Comporta , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Reprodutibilidade dos TestesRESUMO
UNLABELLED: Somatostatin receptor scintigraphy (SRS) has been shown to reveal sarcoidosis sites. The aim of this study was to prospectively compare SRS and gallium scintigraphy in the evaluation of pulmonary and extrapulmonary involvement in patients with proven sarcoidosis. METHODS: Eighteen patients with biopsy-proven sarcoidosis were included. Nine were or recently had been receiving steroid therapy at the time of the examination. Planar gallium scintigraphy (head, chest, abdomen, and pelvis) and thoracic SPECT were performed at 48-72 h after injection of a mean dose of 138 +/- 21 MBq 67Ga. Planar SRS and thoracic SPECT were performed at 4 and 24 h after injection of a mean dose of 148 +/- 17 MBq 111n-pentetreotide. RESULTS: Gallium scintigraphy found abnormalities in 16 of 18 patients (89%) and detected 64 of 99 clinically involved sites (65%). SRS found abnormalities in 18 of 18 patients and detected 82 of 99 clinically involved sites (83%). Of the 9 treated patients, gallium scintigraphy found abnormalities in 7 (78%), detecting 23 of 39 clinically involved sites (59%), whereas SRS found abnormalities in 9, detecting 32 of 39 clinically involved sites (82%). CONCLUSION: This study suggests that, compared with gallium scintigraphy, SRS appears to be accurate and contributes to a better evaluation of organ involvement in sarcoidosis patients, especially those treated with corticosteroids.
Assuntos
Radioisótopos de Gálio , Radioisótopos de Índio , Receptores de Somatostatina/análise , Sarcoidose Pulmonar/diagnóstico por imagem , Sarcoidose/diagnóstico por imagem , Somatostatina/análogos & derivados , Tomografia Computadorizada de Emissão de Fóton Único , Corticosteroides/uso terapêutico , Adulto , Feminino , Humanos , Masculino , Estudos Prospectivos , Sarcoidose/tratamento farmacológico , Sarcoidose/metabolismo , Sarcoidose Pulmonar/tratamento farmacológico , Sarcoidose Pulmonar/metabolismoRESUMO
UNLABELLED: Exercise lung 201 TI uptake calculated with planar imaging has an important diagnostic and prognostic value in patients with coronary artery disease (CAD). However, its value with SPECT imaging raises methodological concerns and is controversial. We studied its value for the discrimination between extensive (E) and limited (L) angiographic CAD with exercise SPECT. METHODS: Four methods of lung-to-heart ratio quantification were calculated in patients with a low likelihood (< 5%) of CAD (n = 62). Their dependent variables were defined, and corresponding correction equations were derived. Receiver operating characteristic (ROC) analysis was performed in a pilot group (L-CAD, n = 49; E-CAD, n = 126) to define the optimal method of calculation of the lung-to-heart ratio. Its best threshold providing the best sensitivity for a specificity of 90% was defined. After correction for dependent variables, the 4 methods were also compared by ROC analysis and the optimal corrected method was compared with the optimal uncorrected method using ROC analysis and the best threshold. The consistency of these results in the validation group (L-CAD, n = 41; E-CAD, n = 122) and of the results of visual analysis of lung 201TI uptake were then verified. RESULTS: On ROC analysis in the pilot group, the optimal method of calculation of the lung-to-heart ratio was the mean activity in a region of interest drawn at the base of the lungs to the mean activity over the heart (Lb/H). For the best threshold, Lb/H presented a sensitivity of 34%. Corrected Lb/H still remained the best method of calculation on ROC analysis compared with the other corrected methods. On ROC analysis, there was no difference between corrected and uncorrected Lb/H. For the best threshold, corrected Lb/H presented a similar sensitivity of 37% compared with uncorrected Lb/H. When applied to the validation group (L-CAD, n = 41; E-CAD, n = 122), the best-defined threshold in the pilot group for corrected Lb/H presented a diagnostic value similar to that in the pilot group (sensitivity, 41%; specificity, 90%), but uncorrected Lb/H presented a higher sensitivity (47%; P < 0.04) and a slightly lower specificity (80%). Results of lung 201TI uptake visual analysis were inconsistent between pilot and validation groups (42% versus 58% sensitivity, P = 0.012; 86% versus 66% specificity, P = 0.023). CONCLUSIONS: For evaluation of E-CAD versus L-CAD, quantification of the exercise lung-to-heart 201TI uptake ratio with SPECT is feasible, reproducible, more discriminate than simple visual analysis, and best calculated as Lb/H. It presents an intrinsic diagnostic value even after correction for other clinically valuable dependent variables.
Assuntos
Doença das Coronárias/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Radioisótopos de Tálio , Tomografia Computadorizada de Emissão de Fóton Único , Estudos de Casos e Controles , Angiografia Coronária , Doença das Coronárias/epidemiologia , Teste de Esforço , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Curva ROC , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
OBJECTIVES: We tested the hypothesis that the reperfusion syndrome (RS), defined as an additional elevation of the ST segment upon reperfusion, may be a marker of microcirculatory reperfusion injury during acute myocardial infarction (AMI). BACKGROUND: The pathophysiology of the RS is unknown, and its prognostic implications are controversial. METHODS: Twenty-one patients with an anterior AMI treated < or =12 h after onset by primary coronary angioplasty (PTCA) were studied. Coronary velocity reserve (CVR), an index of microcirculatory function, was measured using a Doppler guidewire. Left ventricular (LV) ejection fraction, infarct size (percent defect) and LV end-systolic volume index (LVESVi) were evaluated by radionuclide ventriculography, 201T1 single-photon emission computed tomography and contrast ventriculography, respectively. RESULTS: Baseline ST elevation and pain-to-TIMI 3 time were similar in patients with and without RS. Patients with RS (10/21) had a lower post-PTCA CVR than patients without RS (median [95% confidence interval]: 1.2 [1-1.3] vs. 1.6 [1.5-1.7], p < 0.005). Even though predischarge CVR was similar in the two groups, infarct size at six weeks (26 [21 to 37] vs. 14 [10-17]% 201T1 defect, p = 0.001) and predischarge LVESVi (45% [40 to 52] vs. 30% [29 to 38] mL/m2, p = 0.001) were larger, and LV ejection fraction at six weeks (40% [37 to 46] vs. 55% [50 to 60], p = 0.004) was lower in patients with RS than in patients without RS. CONCLUSIONS: Patients with RS during primary PTCA for an anterior AMI have a transiently lower CVR than patients without RS, but sustained LV dysfunction and larger infarct size, suggesting that RS is a marker of microcirculatory reperfusion injury.
Assuntos
Circulação Coronária , Infarto do Miocárdio/complicações , Infarto do Miocárdio/diagnóstico , Traumatismo por Reperfusão Miocárdica/etiologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Função Ventricular Esquerda , Idoso , Angioplastia Coronária com Balão , Biomarcadores , Ecocardiografia Doppler , Eletrocardiografia , Feminino , Seguimentos , Humanos , Masculino , Microcirculação , Pessoa de Meia-Idade , Infarto do Miocárdio/terapia , Prognóstico , Ventriculografia com Radionuclídeos , Índice de Gravidade de Doença , Volume Sistólico , Fatores de Tempo , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
UNLABELLED: 201TI reverse redistribution is a common finding early after reperfusion therapy for myocardial infarction. Its mechanism and clinical implications remain unclear. The aim of this study was to clarify the relationships between reverse redistribution, microvascular perfusion, and myocardial viability. METHODS: Resting, 10-min-postinjection, and redistribution 201TI data obtained for 33 patients 8 and 42 d after the onset of acute myocardial infarction were compared with echocardiographic wall motion measured acutely and on day 42. Microvascular perfusion was assessed by myocardial contrast echocardiography performed 10 min after restoration of complete patency of the infarct artery. RESULTS: Marked significant reverse redistribution was found on day 8 (absolute change, 7.5%+/-7.9% of the 10-min-postinjection defect size; P<5x0.000001) and significantly decreased on day 42 (2.7%+/-6.8%; P = 0.004 between days 8 and 42). The 10-min-postinjection defect size best predicted the final infarct size on day 42 and was closely related to microvascular perfusion. Patients with adequate reperfusion had a smaller postinjection defect on day 8 (21.1%+/-14.6%) and a larger reverse redistribution (10.2%+/-6.1%) than did patients with no reflow (35.3%+/-13% and 3.2%+/-9.2%, respectively; P<0.04 for both). CONCLUSION: Reverse redistribution was marked early after myocardial infarction in patients with complete patency of the infarct artery and decreased in subsequent weeks. Reverse redistribution was associated with restoration of adequate microvascular reperfusion and with myocardial salvage and viability. The early postinjection scans on day 8 were the relevant images for assessing myocardial salvage and predicting wall motion recovery.