Renata Christian Martins Felix

Dual-head coincidence gamma camera FDG-PET before and after autologous bone marrow mononuclear cell implantation in ischaemic stroke

A 54-year-old woman was admitted with acute ischaemic stroke of the left middle cerebral artery. Five days after the stroke, 1.0×10 autologous bonemarrowmononuclear cells were delivered to the left cerebral middle artery via a balloon catheter as part of a research protocol. Neurological examination before the stem cell therapy showed dysarthria, right motor deficit and global aphasia, with a score of 17 on the National Institute of Health Stroke Scale (NIHSS). Brain perfusion Tc-ECD SPECT (a, b) and brain FDG PET (c, d) using a dual-head coincidence gamma camera with 1-in. detectors were performed before and 1 week after the procedure. There was severe left parietal hypoperfusion and hypometabolism at baseline (a, c). One week after the procedure, even though brain SPECT (b) showed only a mild increase in perfusion at the stroke site, PET (d) demonstrated intense FDG uptake in the treated area, suggesting the presence of metabolically viable cells in the infarcted area. Magnetic resonance imaging demonstrated no anatomical or signal changes relative to baseline that were suggestive of an infectious process after stem cell delivery. Furthermore, the patient had no clinical or laboratory evidence of infection. One month after cell transplantation, the patient showed an improvement in the NHISS score of five points. No major adverse event occurred. The observed changes in glucose metabolic activity in the brain tissue affected by stroke may represent cellular activity or engraftment of the implanted cells, a prerequisite for the success of cell therapy. Furthermore, FDG PET can provide functional data on the metabolic response of brain cells to this promising stroke therapy [1–3].

Budget impact of applying appropriateness criteria for myocardial perfusion scintigraphy: The perspective of a developing country.

Abstract Myocardial perfusion imaging is widely used for the risk stratification of coronary artery disease. In view of its cost, besides radiation issues, judicious evaluation of the appropriateness of its indications is essential to prevent an unnecessary economic burden on the health system. We evaluated, at a tertiary-care, public Brazilian hospital, the appropriateness of myocardial perfusion scintigraphy indications, and estimated the budget impact of applying appropriateness criteria. An observational, cross-sectional study of 190 patients with suspected or known coronary artery disease referred for myocardial perfusion imaging was conducted. The appropriateness of myocardial perfusion imaging indications was evaluated with the Appropriate Use Criteria for Cardiac Radionuclide Imaging published in 2009. Budget impact analysis was performed with a deterministic model. The prevalence of appropriate requests was 78%; of inappropriate indications, 12%; and of uncertain indications, 10%. Budget impact analysis showed that the use of appropriateness criteria, applied to the population referred to myocardial perfusion scintigraphy within 1 year, could generate savings of

Nuclear medicine in the management of patients with heart failure: guidance from an expert panel of the International Atomic Energy Agency (IAEA)

64,252.04 dollars. The 12% inappropriate requests for myocardial perfusion scintigraphy at a tertiary-care hospital suggest that a reappraisal of MPI indications is needed. Budget impact analysis estimated resource savings of 18.6% with the establishment of appropriateness criteria for MPI.

Gastrointestinal bleeding diagnosed by red blood cell scintigraphy in a patient with aortic stenosis: a case of Heyde syndrome.

Heart failure is increasing worldwide at epidemic proportions, resulting in considerable disability, mortality, and increase in healthcare costs. Gated myocardial perfusion single photon emission computed tomography or PET imaging is the most prominent imaging modality capable of providing information on global and regional ventricular function, the presence of intraventricular synchronism, myocardial perfusion, and viability on the same test. In addition, 123I-mIBG scintigraphy is the only imaging technique approved by various regulatory agencies able to provide information regarding the adrenergic function of the heart. Therefore, both myocardial perfusion and adrenergic imaging are useful tools in the workup and management of heart failure patients. This guide is intended to reinforce the information on the use of nuclear cardiology techniques for the assessment of heart failure and associated myocardial disease.

Prevalência de isquemia induzida por estresse mental

The authors report a case of small bowel bleeding diagnosed by Tc-99m-labeled red blood cell (RBC) scintigraphy during the postoperative period after aortic valve replacement. There is a relationship between aortic valve stenosis and gastrointestinal bleeding in elderly patients, called Heyde syndrome. The described patient had chronic anemia that worsened after surgery. RBC scintigraphy localized the source of bleeding from jejunal angiodysplasia confirmed by mesenteric angiography. This case illustrates the diagnostic information provided by RBC scintigraphy in this syndrome.

Uso da cintilografia miocárdica em repouso durante dor torácica para descartar infarto agudo do miocárdio

BACKGROUND The myocardial radionuclide imaging with mental distress seems to induce ischemia through a particular physiopathology when compared to radionuclide imaging with physical or pharmacological distress. OBJECTIVE To assess the prevalence of induced myocardial ischemia by mental distress in patients with thoracic pain and radionuclide imaging with normal conventional distress, with 99mTc-Sestamibi. METHODS Twenty-two patients were admitted with thoracic pain at emergency or were referred to the nuclear medicine service of our institution, where myocardial radionuclide imaging of distress or rest without ischemic alterations was carried out. The patients were, then, invited to go through an additional phase with mental distress induced by color conflict (Strop Color Test) with the objective of detecting myocardial ischemia. Two cardiologists and nuclear physicians performed the blind analysis of perfusional data and consequent quantification through Summed Difference Score (SDS), punctuating the segments that were altered after mental distress and comparing it to the rest period image. The presence of myocardial ischemia was considered if SDS > or = 3. RESULTS The prevalence of mental distress-induced myocardial ischemia was 40% (9 positive patients). Among the 22 studied patients, there were no statistical differences with regard to the number of risk factors, mental distress-induced hemodynamic alterations, usage of medications, presented symptoms, presence or absence of coronary disease and variations of ejection fraction and final systolic volume of Gated SPECT. CONCLUSION In a selected sample of patients with thoracic pain and normal myocardial radionuclide imaging, the research of myocardial ischemia induced by mental distress through radionuclide imaging may be positive in up to 40% of cases.

Use of resting myocardial scintigraphy during chest pain to exclude diagnosis of acute myocardial infarction

BACKGROUND Images of myocardial perfusion taken during an episode of chest pain have been used for patients in the emergency department. OBJECTIVE To evaluate the operating characteristics of 99mTc-Tetrofosmin scintigraphy during an episode of chest pain to exclude the diagnosis of acute myocardial infarction. METHODS One hundred and eight patients admitted with chest pain, or up to four hours after the end of symptoms and nondiagnostic electrocardiogram, underwent resting scintigraphy and measurement of troponin I concentrations. Patients with a history of myocardial infarction (MI) were not excluded (24 patients). Troponin I concentrations were determined at admission and 6 hours later. Nuclear physicians performed a blind analysis of the images, and myocardial infarction was confirmed whenever troponin I level increase was three times that of the control. RESULTS Resting perfusion image was abnormal in all 6 patients with MI. Only 1 patient had a normal image and increased troponin levels. Fifty-five patients had positive images without MI, and 46 patients had normal images and troponin levels. The prevalence of the disease was 6.5%. The sensitivity and specificity of the resting images during an episode of chest pain to diagnose MI was 85.7% and 45.5%, respectively. The negative predictive value was 97.7%. CONCLUSION Patients undergoing chest pain protocol with SPECT showed an excellent negative predictive value to exclude diagnosis of myocardial infarction. These results suggest that resting perfusion image is an important tool at the chest pain unit.FUNDAMENTO: A imagem de perfusao miocardica adquirida durante episodio de dor toracica tem sido utilizada nos pacientes na sala de emergencia. OBJETIVO: Avaliar as caracteristicas operacionais da cintilografia com 99mTc-Tetrofosmin durante episodio de dor toracica para descartar o diagnostico de infarto agudo do miocardio. METODOS: 108 pacientes admitidos com dor toracica ou ate quatro horas do termino dos sintomas e eletrocardiograma nao diagnostico realizaram cintilografia em repouso e dosagens de troponina I. Pacientes com passado de infarto do miocardio (IM) nao foram excluidos (24 pacientes). Troponina I foi dosada na admissao e seis horas apos. Medicos nucleares realizaram analise cega das imagens. Infarto do miocardio foi confirmado com elevacao da troponina I maior que tres vezes o controle. RESULTADOS: A imagem perfusional de repouso foi anormal em todos os seis pacientes com IM. Apenas um paciente apresentou imagem normal e elevacao da troponina. Outros 55 pacientes obtiveram imagem positiva sem IM e 46 pacientes com imagens e troponinas normais. A prevalencia da doenca foi 6,5%. A sensibilidade da imagem de repouso durante dor toracica para a evidencia de IM foi 85,7% e especificidade de 45,5%. O valor preditivo negativo foi 97,7%. CONCLUSAO: Pacientes submetidos ao protocolo de dor toracica com cintilografia de perfusao miocardica demonstraram um excelente valor preditivo negativo para afastar o diagnostico de infarto do miocardio. Estes resultados sugerem que a imagem de perfusao em repouso e uma ferramenta importante na unidade de dor toracica.

Positron Emission Tomography in Inflammatory Cardiovascular Diseases

BACKGROUND Images of myocardial perfusion taken during an episode of chest pain have been used for patients in the emergency department. OBJECTIVE To evaluate the operating characteristics of 99mTc-Tetrofosmin scintigraphy during an episode of chest pain to exclude the diagnosis of acute myocardial infarction. METHODS One hundred and eight patients admitted with chest pain, or up to four hours after the end of symptoms and nondiagnostic electrocardiogram, underwent resting scintigraphy and measurement of troponin I concentrations. Patients with a history of myocardial infarction (MI) were not excluded (24 patients). Troponin I concentrations were determined at admission and 6 hours later. Nuclear physicians performed a blind analysis of the images, and myocardial infarction was confirmed whenever troponin I level increase was three times that of the control. RESULTS Resting perfusion image was abnormal in all 6 patients with MI. Only 1 patient had a normal image and increased troponin levels. Fifty-five patients had positive images without MI, and 46 patients had normal images and troponin levels. The prevalence of the disease was 6.5%. The sensitivity and specificity of the resting images during an episode of chest pain to diagnose MI was 85.7% and 45.5%, respectively. The negative predictive value was 97.7%. CONCLUSION Patients undergoing chest pain protocol with SPECT showed an excellent negative predictive value to exclude diagnosis of myocardial infarction. These results suggest that resting perfusion image is an important tool at the chest pain unit.FUNDAMENTO: A imagem de perfusao miocardica adquirida durante episodio de dor toracica tem sido utilizada nos pacientes na sala de emergencia. OBJETIVO: Avaliar as caracteristicas operacionais da cintilografia com 99mTc-Tetrofosmin durante episodio de dor toracica para descartar o diagnostico de infarto agudo do miocardio. METODOS: 108 pacientes admitidos com dor toracica ou ate quatro horas do termino dos sintomas e eletrocardiograma nao diagnostico realizaram cintilografia em repouso e dosagens de troponina I. Pacientes com passado de infarto do miocardio (IM) nao foram excluidos (24 pacientes). Troponina I foi dosada na admissao e seis horas apos. Medicos nucleares realizaram analise cega das imagens. Infarto do miocardio foi confirmado com elevacao da troponina I maior que tres vezes o controle. RESULTADOS: A imagem perfusional de repouso foi anormal em todos os seis pacientes com IM. Apenas um paciente apresentou imagem normal e elevacao da troponina. Outros 55 pacientes obtiveram imagem positiva sem IM e 46 pacientes com imagens e troponinas normais. A prevalencia da doenca foi 6,5%. A sensibilidade da imagem de repouso durante dor toracica para a evidencia de IM foi 85,7% e especificidade de 45,5%. O valor preditivo negativo foi 97,7%. CONCLUSAO: Pacientes submetidos ao protocolo de dor toracica com cintilografia de perfusao miocardica demonstraram um excelente valor preditivo negativo para afastar o diagnostico de infarto do miocardio. Estes resultados sugerem que a imagem de perfusao em repouso e uma ferramenta importante na unidade de dor toracica.

Rapid assessment of rest myocardial ischaemia in the Chest Pain Unit

A tomografia por emissão de pósitrons (PET) é uma tecnologia do campo da Medicina Nuclear, concebida no final da década de 1950 com o objetivo de mapear a função cerebral. O desenvolvimento da técnica e a produção de novos radiofármacos emissores de pósitrons possibilitaram seu emprego incipiente na prática clínica a partir dos anos 1980-19901. Ultimamente, os equipamentos consistem de um sistema que integra a PET e a tomografia computadorizada (CT), trazendo vantagens de melhora da qualidade da imagem e correlação anatômica dos achados metabólicos2. Sua aplicabilidade tem se ampliado em todo o mundo nos últimos anos. Fluordesoxiglicose (18F-FDG) é o radiofármaco mais utilizado para a realização de exames de PET, em razão da meia-vida física relativamente longa (110 minutos) em relação a materiais emissores de pósitrons, enquanto alguns outros possuem meia-vida de pouquíssimos minutos ou até segundos; e também por apresentar um papel biológico bem definido no metabolismo glicolítico1.

Utilización de la centellografía miocárdica en reposo durante dolor torácico para descartar infarto agudo de miocardio

A 76-year-old man with a history of coronary bypass graft surgery presented to the Chest Pain Unit with chest discomfort. He underwent myocardial perfusion imaging (MPI) with 99m Tc-sestamibi. Immediately after acquisition of the rest scan he developed a new chest pain episode and received an additional tracer injection. The new images showed hypoperfusion in the inferior and inferolateral walls that were not observed in the previous rest scan images (a arrows). A coronary angiogram revealed subtotal proximal occlusion of a saphenous vein graft to the right coronary artery (b arrow) which was submitted to successful stent implantation. Acute coronary syndrome results from the combination of intermittent thrombotic occlusion and vasoconstriction resulting in markedly decreased regional myocardial perfusion [1]. Abnormal rest MPI in patients with acute chest pain is highly associated with acute myocardial infarction or the need for subsequent coronary revascularization [2]. These images demonstrate the exquisite sensitivity of MPI to changes in rest myocardial perfusion over a short period.