Autonomic Innervation Evaluation in Cardiac Disease

Abstract Cardiovascular diseases are among the leading causes of mortality and morbidity in the world. In different cardiac diseases, the neuronal function of the heart is impaired. Nevertheless, the development of a simple method to assess the autonomic effects on the heart and/or autonomic dysfunction is a challenge. The evaluation of autonomic innervation in cardiac diseases has helped to improve the knowledge of the pathophysiology of these conditions, as well as to provide information on their prognosis. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are currently the only imaging methods that allow in vivo assessment of cardiac innervation. The majority of SPECT and PET radiotracers evaluate sympathetic neuronal integrity using presynaptic imaging agents that are either labeled as endogenous transmitters or analogues. Postsynaptic imaging agents have also been developed to study sympathetic neuronal integrity, as well as tracers to investigate the parasympathetic nervous system. These methods may be used to analyze the innervation of the heart and allow for early detection of abnormalities caused by, for example, ischemia, heart failure, cardiomyopathies, cardiotoxicity, and arrhythmogenic disorders. This review provides an overview of cardiac innervation evaluation and their application in the assessment of heart disease.

99mTc-thymine scintigraphy may be a promising method in the diagnosis of breast cancer

OBJECTIVE: Mammography has been established as the gold standard for the detection of breast cancer, and imaging techniques such as ultrasonography, magnetic resonance imaging, scintigraphy and positron emission tomography may be useful to improve its sensitivity and specificity. The objective of this study with breast scintigraphy was to evaluate the uptake of 99mTc-thymine in mammary lesions. METHODS: A total of 45 patients were included in this study. Thirty-three patients (73%) were subjected to surgery or percutaneous biopsy, providing histopathological data. The other 12 patients who remained under surveillance received clinical examinations and biannual mammography with a normal follow-up of at least three years, the data from which were used for comparison with the scintimammography results. RESULTS: The majority of patients (64.4%) had clinically impalpable lesions with a mammogram diagnosis of microcalcifications, impalpable nodules, or focal asymmetry. Of the studied lesions, 87% were smaller or equal to 20 mm in diameter, and 22% had malignant histopathological findings. Scintigraphy with 99mTc-thymine had a sensitivity of 70%, a specificity of 85.7%, positive and negative predictive values of 58.3% and 90.9%, respectively, and an accuracy of 82.2%. CONCLUSIONS: The results of this study are consistent with those previously reported by other authors. The good specificity and high negative predictive value of this technique and the absence of uptake in the heart indicate that it may be a promising complementary method in clinical practice and that it may contribute to reducing unnecessary benign biopsies.