Left ventricular functional parameters by gated SPECT myocardial perfusion imaging in a Latin American country.

BACKGROUND: There is paucity of data on left ventricular (LV) functional parameters using gated SPECT myocardial perfusion imaging (MPI) from the Latin American region. This study provides detailed information in low-risk patients both at rest and during exercise. METHODS AND RESULTS: We studied 90 patients (50 men) with a very low likelihood of coronary artery disease. Gated-SPECT MPI was performed with Tc-99m MIBI using a 2-day protocol, with 16 frames/R-R cycle. The LV ejection fraction and volumes were not different between the rest and post-stress images. LVEF was 68 ± 7% post-stress and 70 ± 7% at rest in women, and 62 ± 7% and 63 ± 7%, respectively, in men (P = .19, .26). LV volumes were larger in men than women (P < .01). There were no differences in most variables obtained at rest or post-stress. Transient ischemic dilatation was similar, with upper limits of 1.20 and 1.19 in women and men, respectively (P = NS). CONCLUSIONS: These data could prove helpful for the interpretation of gated SPECT MPI data in Latin America using identical protocol as used in this study.

Relationship between transient ischemic dilatation and changes in heart rate during gated SPECT acquisition in a low-risk population without perfusion defects.

OBJECTIVES: Transient ischemic dilatation (TID) in myocardial perfusion single photon emission computed tomography (SPECT) is considered a marker of poor prognosis. However, it has been suggested that some cases are due to apparent volumetric changes secondary to differences in heart rate (HR) at the time of acquisition. We assessed the correlation between transient dilatation and HR in low risk patients with no perfusion defects. METHODS: We retrospectively analyzed patients sent for 99mTc-MIBI SPECT using a 2-day protocol. We recorded the median HR during acquisition and the HR difference (HRD) between the rest and post-stress. We obtained the medium ventricular volume, end-diastolic volume (EDV), and end-systolic volume (ESV). We included patients in which TID using medium ventricular volume (TIDMV) was ≥1.2. TID was also calculated for the EDV and ESV (TIDEDV, TIDESV). We excluded patients with known coronary artery disease, perfusion defects, various ECG disorders, positive stress test, or ESV < 10 ml. RESULTS: From a total of 2006 patients, 63 (50 exercise, 13 dipyridamole) met the criteria for analysis (age 63.8 ±â€…9.7, 44 men). TIDMV was 1.29 ±â€…0.09 and HRD 9.8 beats per minute (BPM) (range -10 to 41). There was positive correlation between HRD and TIDMV ( r  = 0.51, P  < 0.001) and TIDEDV ( r  = 0.5, P  < 0.001), but not TIDESV ( r  = 0.23, P  = 0.07). Correlation was stronger when HRD was ≥10 BPM ( r  = 0.67, P  < 0.001). CONCLUSION: TID without perfusion defects should be interpreted with caution in the presence of HRD ≥ 10 BPM during post-stress acquisition.

Current status of nuclear cardiology practice in Latin America and the Caribbean, in the era of multimodality cardiac imaging approach: 2022 update.

Cardiovascular diseases (CVDs) are the leading cause of mortality in Latin America and the Caribbean (LAC), with the risk in men being slightly higher than in women. The coronavirus disease 2019 (COVID-19) pandemic caused a significant reduction in the number of cardiac diagnostic procedures globally and in particular in LAC. Nuclear cardiology is available in the region, but there is variability in terms of existing technology, radiopharmaceuticals, and human resources. In the region, there are 2385 single photon emission computed tomography (SPECT) and 315 PET scanners, Argentina and Brazil have the largest number. There is an increasing number of new technologies such as cadmium-zinc-telluride (CZT) cardiac-dedicated gamma cameras, SPECT/computed tomography (CT), and PET/CT. All countries performed myocardial perfusion imaging studies, mainly gated-SPECT; the rest are multi-gated acquisition, mainly for cardiac toxicity; detection of viability; rest gated SPECT in patients with dilated cardiomyopathy, and bone-avid tracer cardiac scintigraphy for transthyretin cardiac amyloidosis diagnosis. Regarding other non-nuclear cardiac imaging modalities, Argentina, Colombia, and Chile have the highest ratio of CT scanners, while Brazil, Argentina, and Chile show the highest ratio of MRI scanners. The development of nuclear cardiology and other advanced imaging modalities is challenged by the high cost of equipment, lack of equipment maintenance and service, insufficient-specific training both for imaging specialists and referring clinicians, and lack of awareness of cardiologists or other referring physicians on the clinical applications of nuclear cardiology. Another important aspect to consider is the necessity of implementing cardiac imaging multimodality training. A joint work of nuclear medicine specialists, radiologists, cardiologists, and clinicians, in general, is mandatory to achieve this goal. National, regional, and international cooperation including support from scientific professional societies such as the American Society of Nuclear Cardiology and Latin American Association of Biology and Nuclear Medicine Societies, cardiological societies, and organizations such as the International Atomic Energy Agency, and Pan American Health Organization, as well as government commitment are key factors in the overall efforts to tackle the burden of cardiovascular diseases in the region.

[99mTc-OCTREOTIDE in patients with neuroendocrine tumors from the GI tract]. / 99mTc-OCTREOTIDE en pacientes con tumores neuroendócrinos gastroenteropancreáticos.

INTRODUCTION: It has been demonstrated that scintigraphy with somatostatin analogues is useful for the diagnosis, staging and follow up of patients with neuroendocrine tumors from the gastrointestinal tract (NET-GIT). Some studies suggest that the use of 99mTc-Hydrazinonicotinyl-Tyr3-octreotide (99mTc-HYNIC-TOC) yields similar diagnostic results than the use of 111In-DTPA-octreotide. OBJECTIVE: To determine the clinical value of scintigraphy using 99mTc-HYNIC-TOC for the detection of primary and secondary lesions in patients with NET-GIT. METHODS: From September 2004 to May 2009, 32 patients (17 women, age range 18 to 82 years old) with histologically proven or clinically suspected NET-GIT underwent scintigraphy using 99mTc-HYNIC-TOC Patients underwent a whole body scan, with additional static images of abdomen and pelvis, followed by SPECT at 4-hrs post injection of 925 MBq of the tracer. Patients underwent clinical, imaging and histopathology follow-up during 3 to 18 months. RESULTS: Histopathology demonstrated carcinoid tumor in 20 patients, insulinoma in 2, gastrinoma in 2 and non-specific NET-GIT in 6. Total sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 87%, 100%, 100%, 89% and 94%, respectively. To detect the primary lesion, the values were 94%, 100% 100%, 94% and 97%, respectively and to detect secondary lesions, 79%, 100%, 100%, 86% and 91%, respectively. CONCLUSIONS: 99mTc-HYNIC-TOC is a specific somatostatin analog, with high affinity to receptor subtype SST-2, widely available and affordable by Latin American countries. It has a good performance to be used for diagnosis, staging and follow-up of patients with NET-GIT.

Resultados a corto plazo del tratamiento con 131I en el bocio multinodular: valor adicional de la estimulación previa con rhTSH / Short-term results of treatment with 131I in multinodular goiter: additional value of previus stimulation with Recombinant human thyrotropin

OBJETIVO: El yodo radiactivo (131I) es una opción terapeútica segura y eficaz cuando se utiliza solo o con la estimulación previa de TSH recombinante humana (rhTSH) en el tratamiento del bocio multinodular (BMN). En espera de ensayos clínicos que determinen la dosis óptima, demuestren seguridad y confirmen la eficacia, diferentes protocolos se utilizan para aplicar la dosis de 131I. Analizamos la respuesta al tratamiento con una dosis calculada por protocolo mixto (dosis fijas y cálculo por porcentaje de captación) en pacientes con BMN toxico y no toxico en nuestro hospital, en el periodo 2010-2013. MATERIALES Y MÉTODOS: Estudio prospectivo en pacientes con BMN no quirúrgico (BMNNQ) que requerían reducción del volumen glandular y/o tratamiento del hipertiroidismo. Se evaluaron 134 pacientes, 14 cumplieron con los criterios de inclusión (13mujeres) de edad media 71.08 años. Un grupo con BMN toxico, otro grupo con BMN no toxico, un tercer grupo con BMN no toxico estimulado con 0,1 mg de rhTSH previo a la dosis. Se evaluó, función tiroidea, captación tiroidea de 99ᵐTc, volumen tiroideo y síntomas compresivos. Se siguió a los pacientes durante 12 meses. RESULTADOS: Se aplicaron dosis entre 15 y 30 mCi de 131I. Remitió el hipertiroidismo en 6 de 7 pacientes. Hubo una reducción del volumen glandular (p<0.01).Los pacientes con estímulo de 0,1 mg rhTSH, aumentaron el porcentaje de captación de 99ᵐTc a las 24 h en un 32.43±10.61 permitiendo aplicar menor dosis de 131I. La tasa de aparición de hipotiroidismo fue de 7.41 por cada 100 pacientes.mes, mayor en pacientes con BMN toxico tratados con dosis bajas (p-=0.03). Hubo una mejoría subjetiva de la clínica compresiva en todos los pacientes. No hubo eventos adversos. CONCLUSIONES: Una dosis de 131I calculada por protocolo mixto es efectiva y segura para la reducción del volumen glandular y control del hipertiroidismo asociado. La estimulación con rhTSH logra el mismo efecto con una menor dosis administrada.

OBJECTIVE: Radioactive iodine (131I) is a safe and effective therapeutic option when used alone or with prior stimulation of recombinant human Thyrotropin (rhTSH) in the treatment of multinodular goiter (MNG). In absence of clinical trials that determine the optimal dose, demonstrate safety and confirm efficacy, different protocols are used to apply the dose of 131I. We analyze the response to treatment with a dose calculated by mixed protocol (fixed doses and calculation by percentage of uptake) in patients with toxic and non-toxic MNG in our hospital, in the period 2010-2013. MATERIALS AND METHODS: Prospective study in patients with non-surgical MNG that required glandular volume reduction and / or treatment of hyperthyroidism. 134 patients were evaluated, 14 met the inclusion criteria (13 women) of average age 71.08 years. One group with toxic MNG, another group with non-toxic MNG and a third with non-toxic multinodular goiter stimulated with 0.1 mg of rhTSH prior to the dose. Patients were followed for 12 months. Upon following, we assessed Thyroid function, 99ᵐTc thyroid uptake, thyroid volume and compressive symptoms. RESULTS: Doses between 15 and 30 mCi of 131I were applied. We observed hyperthyroidism remission in 6 of 7 patients. There was a reduction in glandular volume (p <0.01) considering all patients. Patients with a stimulus of 0.1 mg rhTSH, increased the percentage of uptake of 99ᵐTc at 24 h by 32.43 ± 10.61, allowing a lower dose of 131I to be applied. The rate of onset of hypothyroidism was 7.41 per 100 patients-month, and was higher in patients with toxic MNG treated with low doses (p = 0.03). There was a subjective improvement of the compression clinic in all patients. No adverse events were observed. CONCLUSIONS: A dose of 131I calculated by a mixed protocol is effective and safe for achieving glandular volume reduction and associated hyperthyroidism control. Stimulation with rhTSH produces the same effect with a lower administered dose.

Amiloidosis cardíaca: valor del diagnóstico molecular con radiotrazadores. Reporte de caso / Cardiac amyloidosis: value of molecular diagnostic with radiotracers. Case report

Resumen: La amiloidosis cardíaca es una entidad poco frecuente y progresiva que resulta en una cardiomiopatía restrictiva produciendo síntomas de falla cardíaca, síncope, arritmias o puede ser un hallazgo de ecocardiografía como pseudohipertrofia del ventrículo izquierdo (VI). La imagen molecular a través de la medicina nuclear permite diferenciar entre los dos tipos más comunes de amiloidosis sin necesidad de biopsia endomiocárdica. Presentamos el caso de un paciente de 75 años, con disnea progresiva, en el que la resonancia magnética (RM) informa sospecha de amiloidosis cardíaca, la que se confirma mediante centellografía.

Summary: Cardiac amyloidosis is a rare and progressive entity that results in a restrictive cardiomyopathy producing symptoms of heart failure, syncope, arrhythmias or it can be a finding of echocardiography as pseudo-hypertrophy of the left ventricle. Molecular imaging with nuclear medicine allows differentiating between the two most common types of amyloidosis without the need for endomyocardial biopsy. We present the case of a 75-year-old male with progressive dyspnea, in whom magnetic resonance imaging shows suspicion of cardiac amyloidosis, which is confirmed by scintigraphy.

El consumo crónico de clorhidrato y/o pasta base de cocaína asocia envejecimiento arterial prematuro y aumento del riesgo cardiovascular / Chronic consumption of hydrochloride and / or cocaine base paste associates premature arterial aging and increased cardiovascular risk

Introducción: el consumo de cocaína en forma de clorhidrato (CC), y especialmente de su pasta base (PBC), es un problema sanitario mayor, entre otros factores, por su incidencia, repercusión y franja etaria a la que involucra. Múltiples efectos cardiovasculares han sido descritos en asociación con el consumo de CC, pero el impacto a corto/mediano plazo del uso crónico de CC y PBC en el sistema arterial en sujetos jóvenes no se ha estudiado. Objetivo: determinar la prevalencia de cambios (alteraciones) arteriales estructurales y/o funcionales en jóvenes consumidores de cocaína o sus derivados. Material y método: se incluyeron 29 sujetos (27 hombres; edad media/rango: 29/20-35 años) con criterios toxicológicos de dependencia a cocaína, más de dos años de consumo, y abstinencia menor a un mes. Se realizó evaluación clínica y paraclínica para cuantificar el riesgo cardiovascular global (escore de riesgo de Framingham [EF] para enfermedad cardiovascular a diez años). Los estudios incluyeron determinación de: 1) presencia de placas de ateroma carotídeas y espesor íntima-media carotídeo (EIMC; ecografía modo-B color y software específico). 2) Rigidez aórtica regional (mediante velocidad de la onda del pulso, [VOP]). 3) Presión de pulso aórtica central (tonometría de aplanamiento). 4) Índice tobillo-brazo (oscilometría). 5) Reactividad vascular, función endotelial, por vasodilatación mediada por flujo (DMF; ecografía modo-B y software específico). Se determinó la edad vascular (EV) mediante análisis multiparamétrico. El envejecimiento arterial precoz (EAP) se definió como la diferencia entre la EV y la edad cronológica. Los datos obtenidos se compararon con valores de normalidad (sujetos control). Resultados: de los 29 pacientes, 10 fueron consumidores de CC, 3 de PBC y 16 de ambas sustancias. El 90% eran fumadores de cigarrillos (promedio de consumo: 14,4 cigarrillos/día). Si bien ningún paciente presentó VOP >10 m/s (punto de normalidad aceptado por la Sociedad Europea de Cardiología), 63,6% tuvo niveles de VOP entre el percentil (p)50 y el p90 de la población control de referencia, y 13,6% por encima del p90 de la misma población, indicando que el 77,2% de los mismos presentaron VOP >p50. Respecto del EIMC, un 8% de los pacientes estudiados tuvo niveles > 0,9 mm, y 69% niveles por encima del p95 de la población de referencia, para sexo y edad.. El análisis de la función endotelial mostró que 13,6% de los pacientes no presentó dilatación arterial (DMF £ 0%) y 36% presentó DMF £ 5%. Finalmente, el 33% de los pacientes presentó niveles de presión de pulso aórtica por encima del nivel umbral (p95), para sexo y edad. La EA fue de 37,1 ± 8,4 años, indicando la existencia de un EAP de 8,1 ± 6,2 años (rango: 3-24 años). Conclusión: los usuarios de cocaína mostraron cambios subclínicos perjudiciales a nivel arterial que se asocian a mayor riesgo cardiovascular. Sus parámetros arteriales presentaron niveles compatibles con los existentes en una población control con una edad de 8,1 ± 6,2 años mayor que la estudiada, indicando que los consumidores de CC y PBC podrían presentar "envejecimiento arterial precoz".

Introduction: cocaine consumption, in particular cocaine base paste, is a major health problem, among other factors, its incidence, impact, and the age group involved. Multiple cardiovascular effects have been described in association with cocaine use but the impact in the short/medium-term chronic use of hydrochloride cocaine and cocaine base paste in the arterial system in young subjects has not been studied.Objective: to determine the prevalence of changes (alterations) arterial structural and/or functional in young cocaine or its derivatives users Method: 29 subjects (age: 20-35 years; 27 men) with toxicological criteria for cocaine dependence, over 2 years old and less than one month withdrawal were included. Clinical and paraclinical evaluation was conducted to quantify the global cardio-vascular risk (10-years Framingham Risk Score for cardiovascular disease). The studies included determination of: 1) presence of carotid atheromatous plaques and carotid intima-media thickness (CIMT; color and B-mode ultra sound and specific software), 2) assessment of regional aortic stiffness by pulse wave velocity (PWV), 3) evaluation of central aortic pulse pressure by applanation tonometry, 4) ankle-brachial index, by oscillometry and 5) vascular reactivity (endothelial function) by flow mediated dilatation (FMD) with B-mode ultra sound and specific software. The vascular age (VA) was calculated by multiparametric analysis. The arterial aging (AA) was defined as the difference between the VA and chronological age. The obtained data were compared with normal values (control subjects). Results: 29 patients were evaluated, 10 patients were users of hydrochloride cocaine, 3 cocaine base paste and 16 of both substances. 90% of patients were smokers (mean consumption: 14.4 cigarettes/day). Although no patient had PWV values above 10 m/s, 63,6% had levels of PWV between p50 and p90 and 13,6% above the p90, indicating that 77% of them presented by PWV over p50. Regarding the CIMT, 8% of the patients studied had levels above 0,9 mm, and 69% higher than p75 levels to age and sex. The endothelial function analysis showed that 13,6% of patients had no arterial dilation (FMD £ 0%) and 36% presented a £ 5% FMD. Finally, 33% of patients had levels of aortic pulse pressure above the threshold level (p95 of the reference control group) for gender and age. The AA was 37.1±8.4 years, indicating the existence of early arterial aging 8.1±6.2 years (range 3-24 years). Conclusion: cocaine users showed adverse subclinical level changes of the structure and function of the arteries which is associated with increased cardiovascular risk. The levels obtained for different arterial parameters evaluated were consistent with those in a control population with an age 8.1±6.2 years older than the study, indicating that users of hydrochloride cocaine and cocaine base paste might present "early arterial aging."