Recurrent angina caused by coronary subclavian steal syndrome confirmed by positron emission tomography.

Coronary subclavian steal syndrome is a rare cause of recurrent angina after coronary artery bypass grafting. Identification of the myocardial ischemic region is crucial because it guides revascularization interventions to improve symptoms and myocardial ischemia. Positron emission computed tomography (PET) with rubidium might be a helpful tool because it identifies ischemia, localizes more precisely the ischemic region, and evaluates coronary flow reserve. Here, we report a case of recurrence of angina after coronary artery bypass grafting caused by an obstruction in the left subclavian artery and consequently by coronary steal syndrome confirmed by PET.

Low-carbohydrate diet versus euglycemic hyperinsulinemic clamp for the assessment of myocardial viability with 18F-fluorodeoxyglucose-PET: a pilot study.

Positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) is considered the gold standard for myocardial viability. A pilot study was undertaken to compare FDG-PET using euglycemic hyperinsulinemic clamp before (18)F-fluorodeoxyglucose ((18)F-FDG) administration (PET-CLAMP) with a new proposed technique consisting of a 24-h low-carbohydrate diet before (18)F-FDG injection (PET-DIET), for the assessment of hypoperfused but viable myocardium (hibernating myocardium). Thirty patients with previous myocardial infarction were subjected to rest (99m)Tc-sestamibi-SPECT and two (18)F-FDG studies (PET-CLAMP and PET-DIET). Myocardial tracer uptake was visually scored using a 5-point scale in a 17-segment model. Hibernating myocardium was defined as normal or mildly reduced metabolism ((18)F-FDG uptake) in areas with reduced perfusion ((99m)Tc-sestamibi uptake) since (18)F-FDG uptake was higher than the degree of hypoperfusion-perfusion/metabolism mismatch indicating a larger flow defect. PET-DIET identified 79 segments and PET-CLAMP 71 as hibernating myocardium. Both methods agreed in 61 segments (agreement = 94.5 %, κ = 0.78). PET-DIET identified 230 segments and PET-CLAMP 238 as nonviable. None of the patients had hypoglycemia after DIET, while 20 % had it during CLAMP. PET-DIET compared with PET-CLAMP had a good correlation for the assessment of hibernating myocardium. To our knowledge, these data provide the first evidence of the possibility of myocardial viability assessment with this technique.

Role of 18F-fluorodeoxyglucose positron emission tomography in preoperative assessment of cytologically indeterminate thyroid nodules.

OBJECTIVE: The objective of the study was to determine the diagnostic accuracy of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) in the preoperative diagnosis of thyroid nodules with indeterminate fine-needle aspiration biopsy results. METHODS: Forty-two consecutive patients with thyroid nodules with indeterminate cytological results participated in this study. Abnormal (18)F-FDG PET uptake was assessed visually and by measuring the maximum standardized uptake value (SUVmax) in thyroid topography. All these results were compared with the final pathological results. RESULTS: The presence of focal uptake correlated with a greater risk of malignancy (P = 0.018). All 11 malignant nodules had focal uptake (sensitivity of 100%). Of the 31 patients with benign nodules, there were 19 with positive uptake (specificity of 38.7%). The pre-PET probability of cancer was 26.2% (11 of 42), and this probability increased to 36.7% after PET for those patients whose exam showed focal uptake (11 of 30). The preoperative use of (18)F-FDG PET would result in a significant reduction (39%, 12 of 31) in the number of thyroidectomies performed in patients with benign lesions. SUVmax could not improve this degree of accuracy. There was no correlation between thyroid nodule size and SUVmax value (P = 0.96). Patients with carcinomas were younger than patients with benign lesions (P = 0.048). There was no other clinical, laboratory, or ultrasonographic variable related to malignancy. CONCLUSIONS: (18)F-FDG PET provides high sensitivity to malignant lesions and may be a potentially useful tool in the evaluation of thyroid nodules with indeterminate cytological findings. For these nodules the number of unnecessary thyroidectomies in a hypothetical algorithm using (18)F-FDG PET would be reduced by 39%.

Ventricular synchrony in patients with dilated cardiomyopathy and normal individuals: assessment by radionuclide ventriculography.

OBJECTIVE: To establish the parameters of intra- and interventricular synchrony in normal individuals and to compare them with patients with dilated cardiomyopathy with and without conduction disorders shown in the electrocardiogram (ECG) examination. METHODS: Three groups of patients were included in this study: 18 individuals (G1) with no cardiomyopathy and with a normal ECG (52+/-12 years, 29% male); 50 patients with dilated cardiomyopathy and severe left ventricular dysfunction, with 20 patients (G2) presenting QRS <120 ms (51+/-10 years, 75% male) and 30 patients (G3) with QRS >120 ms (57+/-12 years, 60% male). All patients underwent RV. Evaluation of left intraventricular dyssynchrony was carried out with the measurement of the phase histogram width and interventricular dyssynchrony was evaluated by the difference of the mean phase angle between the right and left ventricles (RLDif). RESULTS: Left ventricle ejection fractions (LVEF)s were: 62 +/- 6% (G1), 27 +/- 7% (G2) and 22 +/- 8% (G3) and right ventricle ejection fractions were: 46 +/- 5% (G1), 41 +/- 6%(G2) and 38 +/- 8% (G3). Evaluation of the phase histogram width was: 89 +/- 18 ms (G1), 203 +/- 54 ms (G2) and 312 +/- 130 ms (G3), p<0.0001. The measurement of RLDif was: 14 +/- 11 ms (G1), 39 +/- 40 ms (G2) and 87 +/- 49 ms (G3); comparing G1 vs. G2 and G1 vs. G3, p<0.0001 and G2 vs. G3, p=0.0007. CONCLUSION: The parameters analyzed discriminate the three groups of patients according to the ventricular synchrony degree. Patients with dilated cardiomyopathy and with no branch block in ECG (QRS <120 ms) may present dyssynchrony, but at a lower degree than patients with widened QRS.

Gender differences in ventricular volumes and left ventricle ejection fraction estimated by myocardial perfusion imaging: comparison of Quantitative Gated SPECT (QGS) and Segami software programs.

OBJECTIVES: To test for gender differences in the measurements obtained by Segami and Quantitative Gated SPECT (QGS) software programs. METHODS: 181 asymptomatic individuals without heart disease were submitted to myocardial perfusion imaging. End-diastolic volumes (EDV), end-systolic volumes (ESV) and left ventricular ejection fraction (LVEF) were measured by QGS and Segami software programs to evaluate the influence of gender, age, weight, height, heart rate, systolic blood pressure, diastolic blood pressure, body mass index and body surface area. RESULTS: The means in the QGS method were: EDV (women= 68 ml; men= 95 ml; p<0.001), LVEF (women= 66.24%; men= 58, 7%) and Segami: EDV (women= 137 ml; men= 174 ml), LVEF (women= 62.67%; men= 58, 52%). There were significant differences between men and women in the EDV (p<0.001), ESV (p<0.001) and LVEF (p=0.001) that persisted after adjusting for body surface area. CONCLUSION: Ventricular volumes were significantly lower and LVEF was significantly higher in women, estimated by QGS or Segami software programs.

Sincronia ventricular em portadores de miocardiopatia dilatada e indivíduos normais: avaliação através da ventriculografia radioisotópica / Ventricular synchrony in patients with dilated cardiomyopathy and normal individuals: assessment by radionuclide ventriculography

OBJETIVO: Estabelecer parâmetros de sincronia intra- e interventricular em indivíduos normais e compará-los aos de pacientes com miocardiopatia dilatada com e sem distúrbios de condução ao eletrocardiograma (ECG). MÉTODOS: Três grupos de pacientes foram incluídos no estudo: 18 indivíduos (G1) sem cardiopatia e com ECG normal (52+/-12 anos, 29 por cento masculinos); 50 portadores de miocardiopatia dilatada e disfunção ventricular esquerda grave, sendo 20 pacientes (G2) com QRS < 120 ms (51+/-10 anos, 75 por cento masculinos) e 30 pacientes (G3) com QRS > 120 ms (57+/-12 anos, 60 por cento masculinos). Todos foram submetidos à ventriculografia radioisotópica (VR). Para avaliar dissincronia intraventricular esquerda foi estudada a largura do histograma de fase e para avaliar dissincronia interventricular foi medida a diferença da média do ângulo de fase entre o ventrículo direito e o esquerdo (DifDE). RESULTADOS: As frações de ejeção do ventrículo esquerdo (FEVE)s foram: 62±6 por cento (G1), 27±6 por cento (G2) e 22±7 por cento (G3) e do VD foram: 46 ± 4 por cento (G1), 38±9 por cento(G2) e 37±9 por cento (G3). A avaliação da largura do histograma de fase foi de: 89±18 ms (G1), 203±54 ms (G2) e 312±130 ms (G3), p<0,0001. A medida da difVDVE foi de: 14±11 ms (G1), 39±40 ms (G2) e 87±49 ms (G3); quando se compararam G1 x G2 e G1 x G3, p<0,0001 e G2 x G3, p=0,0007. CONCLUSÃO: Os parâmetros analisados discriminam os três grupos de pacientes de acordo com o grau de sincronia ventricular. Pacientes com miocardiopatia dilatada e sem bloqueio de ramo ao ECG (QRS < 120 ms) podem apresentar dissincronia, porém em menor grau que os pacientes com QRS alargado.

OBJECTIVE: To establish the parameters of intra- and interventricular synchrony in normal individuals and to compare them with patients with dilated cardiomyopathy with and without conduction disorders shown in the electrocardiogram (ECG) examination. METHODS: Three groups of patients were included in this study: 18 individuals (G1) with no cardiomyopathy and with a normal ECG (52±12 years, 29 percent male); 50 patients with dilated cardiomyopathy and severe left ventricular dysfunction, with 20 patients (G2) presenting QRS <120ms (51±10 years, 75 percent male) and 30 patients (G3) with QRS >120ms (57±12 years, 60 percent male). All patients underwent RV. Evaluation of left intraventricular dyssynchrony was carried out with the measurement of the phase histogram width and interventricular dyssynchrony was evaluated by the difference of the mean phase angle between the right and left ventricles (RLDif). RESULTS: Left ventricle ejection fractions (LVEF)s were: 62 ± 6 percent (G1), 27 ± 7 percent (G2) and 22 ± 8 percent (G3) and right ventricle ejection fractions were: 46 ± 5 percent (G1), 41 ± 6 percent(G2) and 38 ± 8 percent (G3). Evaluation of the phase histogram width was: 89 ± 18 ms (G1), 203 ± 54 ms (G2) and 312 ± 130 ms (G3), p<0.0001. The measurement of RLDif was: 14 ± 11 ms (G1), 39 ± 40 ms (G2) and 87 ± 49 ms (G3); comparing G1 vs. G2 and G1 vs. G3, p<0.0001 and G2 vs. G3, p=0.0007. CONCLUSION: The parameters analyzed discriminate the three groups of patients according to the ventricular synchrony degree. Patients with dilated cardiomyopathy and withno branch block in ECG (QRS <120 ms) may present dyssynchrony, but at a lower degree than patients with widened QRS.

Diferenças relacionadas ao sexo nos volumes ventriculares e na fração de ejeção do ventrículo esquerdo estimados por cintilografia de perfusão miocárdica: comparação entre os programas Quantitative Gated SPECT (QGS) e Segami / Gender differences in ventricular volumes and left ventricle ejection fraction estimated by myocardial perfusion imaging: comparison of Quantitative Gated SPECT (QGS) and Segami software programs

OBJETIVO: Analisar as diferenças relacionadas ao sexo nas medidas obtidas pelos programas Segami e Quantitative Gated SPECT (QGS). MÉTODOS: Cento e oitenta e um indivíduos assintomáticos sem evidência de cardiopatia foram submetidos a estudos de perfusão miocárdica. O volume diastólico final (VDF), volume sistólico final (VSF) e a fração de ejeção do ventrículo esquerdo (FEVE) foram quantificados pelos programas QGS and Segami para avaliar a influência do sexo, idade, peso, altura, freqüência cardíaca, pressão arterial sistólica, pressão arterial diastólica, índice de massa corporal e área de superfície corporal. RESULTADOS: As médias obtidas com o método QGS foram VDF (mulheres = 68 ml; homens = 95 ml; p < 0,001) e FEVE (mulheres = 66,24 por cento; homens = 58,7 por cento), e com o Segami, VDF (mulheres = 137 ml; homens = 174 ml) e FEVE (mulheres = 62,67 por cento; homens = 58,52 por cento). Foram observadas diferenças significantes entre homens e mulheres no VDF (p < 0,001) e VSF (p < 0,001), que persistiram após o ajuste em relação à área de superfície corporal. CONCLUSÃO: Os volumes ventriculares foram significantemente menores e a FEVE foi significantemente maior em mulheres, de acordo com os programas QGS e Segami.

OBJECTIVES: To test for gender differences in the measurements obtained by Segami and Quantitative Gated SPECT (QGS) software programs. METHODS: 181 asymptomatic individuals without heart disease were submitted to myocardial perfusion imaging. End-diastolic volumes (EDV), end-systolic volumes (ESV) and left ventricular ejection fraction (LVEF) were measured by QGS and Segami software programs to evaluate the influence of gender, age, weight, height, heart rate, systolic blood pressure, diastolic blood pressure, body mass index and body surface area. RESULTS: The means in the QGS method were: EDV (women= 68 ml; men= 95 ml; p<0.001), LVEF (women= 66.24 percent; men= 58, 7 percent) and Segami: EDV (women= 137 ml; men= 174 ml), LVEF (women= 62.67 percent; men= 58, 52 percent). There were significant differences between men and women in the EDV (p<0.001), ESV (p<0.001) and LVEF (p=0.001) that persisted after adjusting for body surface area. CONCLUSION: Ventricular volumes were significantly lower and LVEF was significantly higher in women, estimated by QGS or Segami software programs.