Dynamic Single-Photon Emission Computed Tomography Data Analysis: Capabilities for Determining Functional Significance of Coronary Artery Atherosclerosis

The aim of the study was to develop the method for collecting and processing scintigraphic data to determine myocardial flow reserve by using gamma-camera with a new type detector based on Cadmium Zinc Telluride (CZT). Sixteen coronary artery disease patients and nine healthy volunteers received cardiac dynamic single-photon emission computed tomography with technetium 99m methoxyisobutylisonitrile ({99m}Tc-MIBI) at rest and during pharmacologic stress test. Data processing involved a formation of regions of interest from the left ventricular (LV) cavity and myocardial walls to build activity-time curves. Myocardial flow reserve index was determined as a quotient of two ratios of mean myocardial counts to area under a curve peak from LV cavity during stress test and at rest. Mean values of myocardial flow reserve index were 1.86 (1.59; 2.2) in group of healthy volunteers and 1.39 (1.12; 1.69) in patients with multivessel coronary artery disease. When the value of this index was less than 1.77, the method allowed for identification of multivessel disease with sensitivity and specificity of 81.8% and 66.7%, respectively. Standard myocardial perfusion scintigraphy in combination with the method of myocardial flow reserve index determination allows for increasing diagnostic significance of the scintigraphic approach for assessment of coronary microcirculation lesions in multivessel coronary artery disease

Lung scintigraphy in differential diagnosis of peripheral lung cancer and community-acquired pneumonia

Ventilation/perfusion lung scintigraphy was performed in 39 patients with verified diagnosis of community-acquired pneumonia (CAP) and in 14 patients with peripheral lung cancer. Ventilation/perfusion ratio, apical-basal gradients of ventilation (U/L(V)) and lung perfusion (U/L(P)), and alveolar capillary permeability of radionuclide aerosol were determined based on scintigraphy data. The study demonstrated that main signs of CAP were increases in ventilation/perfusion ratio, perfusion and ventilation gradient on a side of the diseased lung, and two-side increase in alveolar capillary permeability rate for radionuclide aerosol. Unlike this, scintigraphic signs of peripheral lung cancer comprise an increase in ventilation/perfusion ratio over 1.0 on a side of the diseased lung with its simultaneous decrease on a contralateral side, normal values of perfusion and ventilation gradients of both lungs, and delayed alveolar capillary clearance in the diseased lung compared with the intact lung

RADIONUCLIDE EVALUATION OF CONTRACTILITY OF THE RIGHT HEART IN MITRAL VALVE STENOSIS

Aim. With the use of radionuclide weight-adjusted tomoventriculography (RTVG), to assess the condition of the right heart chambers in mitral valve stenosis (MV) of rheumatic origin.Material and methods. Totally, 20 patients studied (mean age — 54,2±8,22 y.) with rheumatic mitral valve lesion, of those 13 were investigated before and after correction of the defect. All patients, before and after correction of the defect were examined with the RTVG.Results. In all patients with the MV defect, we found a decrease of regional contractility of the RV. Patients with MV defects, related to the comparison group, had significantly more statistically decreased EF, MCI and SSN/Z, EF and higher values of EDV of the RV. Valve defect correction led to statistically more significant decrease of ESV, increase of MCI and EF RV. The sizes of the right atrium, measured with RTVG, were significantly higher comparing to the controls, and after correction of the defect, they reduced.Conclusion. The RTVG method could be applied for non-invasive assessment of the right heart chambers function in patients with MV stenosis of rheumatic origin

Prospects for Creation of Cardioprotective and Antiarrhythmic Drugs Based on Opioid Receptor Agonists

It has now been demonstrated that the μ, δ(1), δ(2), and κ(1) opioid receptor (OR) agonists represent the most promising group of opioids for the creation of drugs enhancing cardiac tolerance to the detrimental effects of ischemia/reperfusion (I/R). Opioids are able to prevent necrosis and apoptosis of cardiomyocytes during I/R and improve cardiac contractility in the reperfusion period. The OR agonists exert an infarct‐reducing effect with prophylactic administration and prevent reperfusion‐induced cardiomyocyte death when ischemic injury of heart has already occurred; that is, opioids can mimic preconditioning and postconditioning phenomena. Furthermore, opioids are also effective in preventing ischemia‐induced arrhythmias

ЭНДОГЕННАЯ ОПИОИДНАЯ СИСТЕМА КАК ЗВЕНО СРОЧНОЙ И ДОЛГОВРЕМЕННОЙ АДАПТАЦИИ ОРГАНИЗМА К ЭКСТРЕМАЛЬНЫМ ВОЗДЕЙСТВИЯМ. ПЕРСПЕКТИВЫ КЛИНИЧЕСКОГО ПРИМЕНЕНИЯ ОПИОИДНЫХ ПЕПТИДОВ

It has been well established that opioid peptides (OPs) affect various hormonal systems. Opioids exhibit stress-limiting and gastro-protective effects in stressed animals, acting via μ- and δ-opioid receptors (OR). Peripheral μ-OR stimulation by endogenous and exogenous opioids increases cardiac tolerance to pathological consequences of stress. Enhancement of prostacyclin synthesis, decrease of thromboxane production as well as suppression of lipid peroxidation can be directly responsible for cardioprotective effects of OPs in stressed animals. Adaptive responses are accompanied by increased OP levels in blood and tissues. Reduction of ventricular arrhythmias induced by repeated short-term immobilization stress is mediated via μ-OR stimulation by endogenous opioids, while δ-OR account for an antiarrhythmic effect of adaptation to chronic intermittent hypobaric hypoxia. The mechanism of infarct size-limiting effect of continuous normobaric hypoxia involves both μ- and δ-OR stimulation. Peptide OR agonists can be considered in future clinical practice for treatment of withdrawal syndrome, stress-related cardiac disease or myocardial injury caused by ischemia-reperfusion insult. Установлено, что опиоидные пептиды (ОП) влияют на различные гормональные системы. Опиоиды оказывают стресс-лимитирующий и гастропротекторный эффект на стрессированных особей, действуя на μ- и δ-опиоидные рецепторы (ОР). Стимуляция периферических μ-ОР эндо- и экзогенными опиоидами способствует повышению толерантности сердца к патогенному действию стресса. Усиление синтеза простациклина, снижение продукции тромбоксана, а также подавление процессов пероксидного окисления липидов (ПОЛ) могут иметь прямое отношение к кардиопротекторному эффекту ОП у стрессированных животных. Адаптация сопровождается увеличением содержания ОП в крови и тканях экспериментальных животных. Снижение частоты возникновения желудочковых аритмий, индуцированное повторными иммобилизациями, опосредуется через стимуляцию μ-ОР эндогенными опиоидами, в то время как δ-ОР ответственны за антиаритмический эффект адаптации к периодической гипобарической гипоксии. Инфаркт-лимитирующий эффект адаптации к непрерывной нормобарической гипоксии зависит от активации μ- и δ-ОР. Пептидные агонисты ОР в будущем могут найти применение в клинической практике в лечении абстинентного синдрома, стресс-индуцированных заболеваний сердца или повреждений миокарда, вызванных ишемией и реперфузией.

Возможности использования сцинтиграфических методов в дифференциальной диагностике острой тромбоэмболии легочной артерии и хронической постэмболической легочной гипертензии

Purpose. The purpose of the study was to evaluate the capabilities of lung scintigraphy and gated equilibrium radionuclide blood-pool SPECT in the differential diagnostics of acute pulmonary embolism and chronic postembolic pulmonary hypertension. Material and methods. The study included 78 patients, which have been divided into two groups: 62 (79.5%) patients had a verified diagnosis of acute pulmonary embolism and 16 (20.5%) patients - chronic postembolic pulmonary hypertension. Patients underwent a full range of clinical and diagnostic examinations, including ventilation/perfusion scintigraphy and gated equilibrium radionuclide blood-pool SPECT; 12 patients underwent multidetector computed tomographic (MDCT) angiography of the pulmonary arteries. Results. According to ventilation/perfusion lung scintigraphy data, perfusion defects were found in the upper and middle parts of the lungs in patients with acute pulmonary embolism. In these patients, perfusion defects were characterized by clear demarcation and by triangular or wedge-like shape. Localizations of the thrombosed vessels did not correspond to the areas with ventilation abnormalities. The ratio of transverse dimensions of right to left ventricular blood pools (RV/LV) in axial slices did not exceed 1.0. In patients diagnosed with chronic postembolic pulmonary hypertension, the areas of abnormal circulation were diffuse; the boundaries between the diseased areas and the intact pulmonary tissue were not clearly demarcated. In these patients, the RV/LV ratio in axial slices exceeded 1.0. Scintigraphic identification of pulmonary disorders was verified by MDCT pulmonary angiography. Conclusion. The use of scintigraphic methods aimed at assessment of the functional states of the heart and the lungs contributed to the accuracy of complicated differential diagnosis of acute pulmonary embolism and chronic postembolic pulmonary hypertension. Diagnostic information acquired with scintigraphic methods allowed for timely administration of adequate therapy.Цель исследования: оценить возможности использования пульмоносцинтиграфии и равновесной радионуклидной вентрикулографии (РРВГ) в комплексной дифференциальной диагностике острой тромбоэмболии легочной артерии (ТЭЛА) и хронической постэмболической легочной гипертензии. Материал и методы. Обследованы 78 больных, которые были разделены на 2 группы: с верифицированным диагнозом острой ТЭЛА - 62 (79,5%) больных и с хронической постэмболической легочной гипертензией-16 (20,5%) больных. Пациенты прошли полный комплекс клинико-диагностических исследований, включающий в себя вентиляционно-перфузионную пульмоносцинтиграфию и РРВГ сердца, мультиспиральная компьютерная томоангиопульмонография проведена 12 больным. Результаты. По данным вентиляционной и перфузионной сцинтиграфии у пациентов с острой ТЭЛА в верхних и средних отделах легких были обнаружены дефекты перфузии, которые характеризовались четкостью контуров, имели треугольную или клиновидную форму, соответствовали бассейну тромбированного сосуда и по локализации не совпадали с областями вентиляционных нарушений. Соотношение поперечных размеров радиоактивного пула крови правого желудочка сердца к левому (ПЖ/ЛЖ) на аксиальных томографических срезах не превышало 1,0. У лиц с хронической постэмболической легочной гипертензией картина нарушений кровоснабжения имела диффузно-неравномерный характер, границы между пораженными отделами и интактной тканью легких были нечеткими. Показатель соотношения поперечных размеров радиоактивного пула крови ПЖ/ЛЖ превышал 1,0. Выявленные сцинтиграфические легочные нарушения были верифицированы результатами рентгеноконтрастной ангиопульмонографии. Выводы. Использование сцинтиграфических методов оценки функционального состояния легких и сердца способствует повышению точности комплексной дифференциальной диагностики ТЭЛА и хронической постэмболической легочной гипертензии, что позволяет своевременно назначить адекватную терапию

ВОЗМОЖНОСТИ РАДИОНУКЛИДНЫХ МЕТОДОВ ИССЛЕДОВАНИЯ В ПРОГНОЗЕ РАЗВИТИЯ СЕРДЕЧНОЙ НЕДОСТАТОЧНОСТИ У БОЛЬНЫХ, ПЕРЕНЕСШИХ ИНФАРКТ МИОКАРДА

In the article possibilities of radionuclide methods of research are shown in prognostication of heart failure and estimation of efficiency of restoration treatment for patients, carrying the heart attack of myocardium.В статье показаны возможности радионуклидных методов исследования в прогнозировании сердечной недостаточности и оценки эффективности восстановительного лечения у больных, перенесших инфаркт миокарда