[Myocardial perfusion evaluated with a 2-isotope technique. Experience with the first 1600 cases in Mexico]. / Perfusión miocárdica valorada con técnica de dos isótopos. Experiencia de los primeros 1600 casos en México.

SPECT has a high sensitivity for the diagnosis of coronary artery disease. Dual isotope protocol using rest thallium and stress MIBI was introduced in Mexico 4 years ago. This protocol reunite the advantages of both radiotracers for the study of myocardial perfusion. We present our experience of the first three years. One thousand six hundred patients were studied with suspected myocardial ischemia; 288 were excluded because of an absence of a proper follow up. In 895 of the 1312 patients a coronariography was performed. Images were evaluated by dividing the heart in 20 segments using a 5 points scale (0 = normal to 4 = absence of perfusion). It was considered a perfusion defect when a segment had a score greater or equal to 2 and the SPECT study was considered abnormal if two or more segments had a MIBI stress score equal or greater than 2. The global sensitivity for diagnosis of ischemia was 96.28%. Dual isotope method is appropriate for the diagnosis of ischemic heart disease. It has a high sensitivity and specificity for the recognition of global coronary disease and for specific coronary territories. This work constitutes the greatest series in Latin America that uses this diagnosis method.

[Myocardial ischemia detection with adenosine administration and SPECT. Initial experience in Mexico]. / Detección de isquemia miocárdica mediante la administración de adenosina y técnica SPECT. Experiencia inicial en México.

UNLABELLED: Myocardial perfusion SPECT has a high sensitivity for the diagnosis of myocardial ischemia. Adenosine has been recently used to induce myocardial ischemia in the United States and Europe. At the present time there is not published experience using adenosine in Mexico. METHOD: We studied 22 patients with suspected myocardial ischemia. Coronary angiography was performed in 17 patients. We used a 8 mCi rest Tc-99m sestamibi followed by a 6 minute infusion of adenosine at a dose of 140 ug/kg/min; 24 mCi of Tc-99m were injected after the third minute of adenosine infusion. Patients returned 2 or 3 days later for a new stress study using physical stress or dipiridamole and the images were read using a 20 segments analysis and each segment was scored using a 5 points scale (0 = normal to 4 = absent uptake). The results were then compared with the adenosine images. RESULTS: The segmental score agreement between adenosine and physical or dipyridamole stress were good with 90% exact correlation. The side effects experienced by patients who received dipyridamole and adenosine were similar. CONCLUSION: Adenosine is a good alternative to induce myocardial ischemia. It showed a good correlation with physical or dipyridamole stress test.

[Simultaneous assessment of perfusion and myocardial viability with 2 isotope studies (thallium at rest and sestamibi in exercise). Initial experience in Mexico and Latin America]. / Valoración simultánea de la perfusión y la viabilidad miocárdica a través del estudio de dos isótopos (Talio reposo/MIBI esfuerzo). Experiencia inicial en México y América Latina.

UNLABELLED: Rest-stress sestamibi single photon emission computed tomography (SPECT) has sensitivity and specificity similar to those of thallium 201 SPECT for detection of coronary artery disease. However, sestamibi is not ideal agent to study myocardial viability. There is not published experience in Latin American using dual isotope SPECT protocol to evaluate myocardial perfusion and viability. We studied 44 consecutive patients with coronary artery disease, 37 of them with previous myocardial infarction. Coronary angiography was performed in all patients. We used a 3 mCi rest T 201 SPECT followed by stress and 25 mCi sestamibi injection. Sestamibi SPECT was performed 30 minutes after exercise or 1 hour after pharmacologic stress with dipyridamole. To validate perfusion findings patients returning next day for rest sestamibi injection and SPECT. Scintigraphic data were read by two blinded expert using 20 SPECT segment analysis and each segment was scored using 5 points scoring system (0 = normal, 4 = absent uptake). The segmental score agreement between rest thallium 201 and rest sestamibi and the comparison of defect reversibility percentage and non reversibility between both protocols was 90.7%. CONCLUSION: Separate acquisition dual isotope myocardial perfusion SPECT is accurate for coronary artery disease evaluation. It showed a good agreement with rest-stress sestamibi SPECT for assessment of rest perfusion defects and reversibility and it was a better method to evaluate myocardial viability.