[Current Possibilities of Using Radiopharmaceuticals to Evaluate Cerebral Blood Flow].

A comparison of the possibilities of using various neurotropic radiopharmaceuticals for scintigraphic evaluation of cerebral perfusion. In the whole range of radiopharmaceuticals used to diagnose cerebral blood flow disorders, there are Ceretec (99mTc-hexamethylpropyleneamine) and Neurolite (N,N-1,2-ethylenediylbis-L-cysteine-diethyl ether), which are the most optimal agents. Due to their high cost and related radiation exposure, the radiopharmaceuticals 123І-IMP (123I-isopropyl-iodoamphetamine) and 201Tl-DDC (diethyldithiocarbamate) labeled with thallium-201 virtually minimize the possibilities of being used in daily clinical practice. Fixation of 99mTc-DDC in the brain proves to be short-term, which is insufficient for tomoscintigraphy studies. Literature has been sought in the Scopus, Web of Scince, Pubmed, EMBASE, and Russian Science Citation Index databases.

[Scintigraphic assessment of alterations in cardiopulmonary haemodynamics and renal functional activity in patients with endured coronary artery bypass grafting].

OBJECTIVE: By means of scintigraphic methods to assess alterations in cardiopulmonary haemodynamics and renal functional activity in patients with coronary artery disease (CAD) after endured coronary artery bypass grafting (CABG) performed in conditions of extracorporeal circulation (EC) and on the functioning heart. MATERIAL AND METHODS: We examined a total of 40 patients presenting with CAD (mean age 54.90±1.12 years) after endured CABG. All patients were subdivided into 2 groups: Group One consisting of 20 patients subjected to CABG performed on the beating heart with the use of myocardial "stabilizer" "Acrobat" (Study Group) and Group Two also comprising 20 patients but undergoing surgery with the use of extracorporeal circulation (Comparison Group). All patients included into the study were subjected to radiocardiopulmonography with (99m)Tc-pertechnetate and dynamic radionuclide renoscintigraphy with (99m)Tc-DTPA before and 6-7 days after operative treatment. RESULTS: In the early postoperative period after CABG, the patients of the both groups were found to have a significant increase in the minute volume, cardiac index, and circulation efficiency coefficient, accompanied by a significant decrease in the period of half-emptying of the left ventricle, thus suggesting improvement of LV contractility. Improved pulmonary microcirculation resulting from operative treatment in the compared groups of patients was confirmed by significantly shortened time of the indicator's passing through pulmonary vessels at the expense of both arterial (TAM) and venous (TVM) components. At the same time, a decrease in these parameters in the Study Group patients was more pronounced as compared with the Comparison Group patients. Thus, the means of the difference between the pre- and postoperative values of TAM and TVM in the Study Group amounted to 1.78 ± .40 s and 1.78 ± 0.32 s, and in the Comparison Group to 0.95 ± 0.22 s and 0.98 ± 0.16 s, respectively (p=0.029 and p=0.031 for TAM and TVM, respectively). The Comparison Group patients after CABG were found to have a significant decrease in the mean values of the total glomerular filtration rate (GFR) in combination with decelerated clearance of the indicator from blood. 30% of patients under the effect of nonpulsating blood flow developed relatively pronounced renal dysfunction (a decrease in the total GFR and/or GRF of one of the kidneys by 15% and more as compared with the initial level). Besides, these patients also demonstrated significant changes in the half-clearance of the radiopharmaceutical from the renal parenchyma and the index of cortical retention of the indicator on the both sides. Unlike the Comparison Group, in patients without EC the average values of the majority of parameters of renal filtration activity underwent no statistically significant alterations as compared with the baseline (prior to CABG) values. CONCLUSION: Coronary artery bypass grafting without cardiac arrest exerts less pronounced negative influence upon the state of the renal function as compared with the open-heart surgery with extracorporeal circulation, which may partially be conditioned by statistically more significant positive dynamics of microcirculation in the system of pulmonary circulation under the effect of myocardial revascularization with the use of the myocardial stabilizer "off-pump".

[Capabilities of radionuclide imaging study in the evaluation of pulmonary hemodynamics and right ventricular function in chronic obstructive pulmonary disease].

OBJECTIVE: To assess the capabilities of radionuclide imaging studies in the evaluation of pulmonary hemodynamics and right ventricular function in chronic obstructive pulmonary disease (COPD). SUBJECT AND METHODS: Twenty-one patients aged 55.8 +/- 9.7 years with COPD (forced expiratory volume in one second (FEV1), 37.43 +/- 15.46%; BODE index, 6.30 +/- 2.66) were examined. A comparison group included 15 patients aged 56.3 +/- 8.3 years without cardiorespiratory pathology. All the patients underwent radionuclide angiopulmonography (RAPG), equilibrium radionuclide tomoventriculography (ERTVG), external respiratory function testing, and determination of the plasma levels of endothelin-1 and stable nitric oxide metabolites. RESULTS: Analysis of the results of ERTVG and RAPG in the study and comparison groups has shown that the chanrades in the lesser circucr moderate. r index and smoking intensity have demonstrated the statistically significant association with the indicators of pulmonary circulation. The plasma level of endothelin-1 was higher1in the patients with COPD than in those in the comparison group. CONCLUSION: Right dysfunction is moderate in COPD as this process is preceded by structural changes in the bronchi, parenchyma, and lung vessels. To identify lesser circulatory dysfunction in COPD, one should orient to the indicators of RAPG that can verify pulmonary hemodynamic disorders and to the data of ERTVG that shows right ventricular systolic and diastolic function and right atrial dimensions.

[Scintigraphic evaluation of impairments in cardiopulmonary hemodynamics and renal functional activity in patients with coronary heart disease and circulatory failure].

OBJECTIVE: To evaluate the relationship between impairments in cardiopulmonary hemodynamics and renal functional activity in patients with circulatory failure, by applying radionuclide studies. MATERIAL AND METHODS: Sixty-nine patients with coronary heart disease (mean age 53.23 +/- 0.87 years) with the development of NYHA functional classes II-III chronic HF were examined. To calculate cardiopulmonary hemodynamic parameters, all the patients underwent 99mTc pertechnetate radiocardiopulmonography. Their renal functional activity was assessed by dynamic radionuclide renal scintigraphy using 99mTc-DTPA. RESULTS: The examinees had most abnormal systemic and pulmonary hemodynamic parameters. Renal dysfunction was detected in 74% of the examinees and reflected by decreased glomerular filtration rates in one or both kidneys and/or a longer tracer elimination half-life from the renal parenchyma. Stepwise regression analysis established a strong inverse correlation between impaired pulmonary circulation, on the one hand, and reduced renal filtration, on the other, and a direct correlation of impairments in renal filtration and evacuation with both left and right ventricular contractility. CONCLUSION: Radionuclide studies are the methods of choice for diagnosis of the cardiorenal continuum.

[Total non-elastic pulmonary resistance and permeability of the alveolar capillary membrane in community-acquired pneumonia].

AIM: To study alveolar capillary membrane permeability (ACMP) and total non-elastic pulmonary resistance (TNPR) in patients with community-acquired pneumonia (CAP) in an acute period. MATERIAL AND METHODS: ACMP of the lungs was studied in 35 CAP patients with ventilation pulmonoscintigraphy. Integral and regional TNPR were registered at inhalation and expiration. Integral TNPR was estimated by simultaneous registration of transpulmonal pressure and spirogram, regional TNPR (in the upper, middle and lower zones of the lungs)--by simultaneous registration of zonal rheograms of ventilation and transpulmonal pressure. Bronchial resistance was measured by body plethismograph (Masterlab pro, Erich Jaeger, Germany). RESULTS: In acute CAP integral TNPR rose while regional values varied. Both integral and regional ACMP for affected and intact lungs were significantly elevated showing systemic impairment of the structures of alveolar-capillary membrane of the lungs. More severe alterations of integral ACMP were seen in the affected lung, of regional--in the affected zones. CONCLUSION: Changes registered in regional TNPR and ACMP may indicate enhanced mechanical activity of the lungs in these zones. This enhanced activity contributes to TNPR overcoming.

[Extrahospital pneumonias: the clinico-scintigraphic characterization and oxidative balance of cells].

Ventilation-perfusion pulmonary scintigraphy was carried out in 30 patients with a verified diagnosis of extra-hospital pneumonia (EHP) and 10 healthy subjects; ventilation-perfusion ratio (V/Q), apex-basis ventilation and perfusion gradient, and the condition of alveolar-capillary permeability (ACP) were analyzed. Clinical symptoms during the debut of EHP were more pronounced in patients with an alveolar type of pulmonary infiltrate (PI) vs. patients with interstitial one: they had pulmonary infiltration syndrome, pleural pain, tachypnoe, tachycardia, a fever of higher than 38 degrees C, and leucocytosis more often. During the acute period of EHP, elevated lipid peroxidation in the erythrocyte membrane as well as a decrease in the content of reduced glutathione and the activity of superoxide dismutase and catalase in erythrocytes did not depend on the type of PI. In EHP, independently of PI type, the study revealed an increase in V/Q of higher than 1.0 on the side of lesion and bilateral (including the healthy side) increase in ACP for radioactive aerosol.

[Possibilities of overcoming difficulties in the differential diagnosis of nonmassive pulmonary thromboembolism in patients taken to the hospital by ambulance].

AIM: To optimize the differential diagnosis of nonmassive pulmonary thromboembolism (PTE) in patients emergently admitted to a multidisciplinary hospital. MATERIALS AND METHODS: The study enrolled 36 patients with nonmassive PTE and 28 with community-acquired pneumonias (ACP). All the patients underwent a comprehensive study, including primarily a clinical study in order to search for the early clinical manifestations of PTE. Ventilation-perfusion lung scintigraphy (VPLS) was performed in 11 patients with nonmassive PTE, 28 with ACP, and 10 healthy volunteers. RESULTS: The initial diagnosis of ACP was established in 26 of the 36 emergently hospitalized patients. Most early clinical manifestations of PTE and A CP were similar; their distinguishing features suggested that there might be nonmassive PTE. It is suggested that VPLS should be used for differential diagnosis in the above cases, by additionally assessing alveolar-capillary permeability. Twenty-eight patients with ACP were found to have a pronounced and significant acceleration of alveolar-capillary permeability in the affected lung at minutes 10 [23.5 +/- 1.9% (versus 8.02 +/- 3.89% in 11 patients with nonmassive PTE; p = 0.01)] and 30 of the study [33.4 +/- 1.9% (versus 13.64 +/- 4.0% in nonmassive PTE; p = 0.004)] while in nonmassive PTE, alveolar-capillary permeability corresponded to the values typical of healthy individuals, without exceeding 12 and 22% at minutes 10 and 30 of the study, respectively. CONCLUSION: VPLS makes it possible to verify or exclude the thromboembolic nature of pulmonary perfusion disorders. If it is difficult to make a diagnosis in the presence of the clinical symptoms characteristic of both nonmassive PTE and ACE, VPLS with an additional assessment of alveolar-capillary permeability, ACP substantially increases the accuracy of differential diagnosis of nonmassive PTE and ACE.

[Ventilation-perfusion pulmonary scintigraphy for diagnosis of pulmonary thromboembolism].

Ventilation-perfusion pulmonary scintigraphy with analysis ofventilation-perfusion ratio, apex-base ventilation and perfusion gradient, pulmonary perfusion, and the condition of alveolar permeability at the 10th and 30th min after inhalation of radiopharmaceutical was carried out in 16 patients with clinical and scintigraphic signs of thromboembolism of distal pulmonary artery branches and 10 controls. Thromboembolism of distal pulmonary artery branches was manifested by an increase in apex-base ventilation and perfusion gradient in both involved and intact lungs vs. the same parameters in healthy people. Patients with bilateral thromboembolism of distal pulmonary artery branches were characterized by an increase in ventilation-perfusion ratio and retardation of alveolar permeability.

[Hemodynamic and anti-ischemic effects of moexipril in patients having postinfarction heart dysfunction and moderate left ventricular heart failure]. / Gemodinamicheskaia i antiishemicheskaia éffektivnost' moéksiprila u bol'nykh s postinfarktnoi disfunktsiei serdtsa i umerenno vyrazhennoi levozheludochkovoi serdechnoi nedostatochnost'iu.

The purpose of the study was to evaluate hemodynamic and anti-ischemic effects of moexipril in patients with postinfarction left ventricular dysfunction (PL VD) and moderate left ventricular heart failure (NYHA functional class II-III). The subjects of the study were 21 male patients (aged 52.4 +/- 1.1 years) with CHD and PLVD, related to old large-focal anterior myocardial Q-wave infarction. 4-week treatment with ACF-inhibitor moexipril in an average dose of 10.7 +/- 0.4 mg per day clinically improved the patients' condition, which was characterized by 32.2% reduction of stenocardia attack frequency (p < 0.01) and 36.4% decrease in nitroglycerin demand (p < 0.01). Activity tolerance increased by 39.2% (p < 0.001), and echoCG found a 16.5% increase of LV ejection fraction (p < 0.05). Conjunctival biomicroscopy showed that moexipril substantially improved microcirculation (MC); total conjunctival index significantly decreased by 21.7%. The results of the 4-week moexipril administration demonstrate hemodynamic and anti-ischemic effects of the new ACF inhibitor, its positive influence on transcapillary oxygen exchange and MC in patients with PLVD, associated with NYHA functional class II-III heart failure.

Myocardial perfusion and left ventricular function in long-term follow-up and prognosis of electrostimulation cardiomyoplasty.

BACKGROUND: Twenty two patients with congestive cardiac failure treated surgically by dynamic cardiomyoplasty (CMP) with m. latissimus dorsi were examined. Myocardial perfusion was assessed with (199)TlCl scintigraphy combined with dipyridamole stress-test. In order to obtain direct evidence of myocardial perfusion from muscular flap we also injected a bolus of (99m)Tc into a. thoracodorsalis, with simultaneous blood sampling from coronary sinus. Haemodynamic parameters were assessed using radionuclide angiography. METHODS: In a year of follow-up all the patients were assigned to one of two groups: eleven patients demonstrated improvement in clinical status (first group) and in another group comprising eleven persons no positive effect or deterioration were obvious (second group). The patients of the first group before operation revealed two times less persistent defect size than patients of the second group. Analysis of integral index of persistent defect revealed more expressive differences between groups. Before the surgical treatment the patients with improvement in clinical status after cardiomyoplasty demonstrated greater size of reversible defect in comparison with patients of the second group. In the second group coronary fraction of thallium accumulation was 1.4 times higher in comparison to the first group, as the result of myocardial hypertrophy in patients with bad prognosis. There were no significant differences between the two groups in Il/m level before cardiomyoplasty. Before the surgical treatment the patients with improvement in clinical status after cardiomyoplasty demonstrated greater ejection fraction in comparison with patients of the second group. RESULTS: Cardiomyoplasty led to a decrease in the mean size of reversible defects due to indirect revascularisation. This hypothesis was testified to by the fact that in patients after cardiomyoplasty nuclide appeared in coronary sinus at 10-12th seconds after injection into artery thoracodorsalis through anastomoses between the latissimus dorsi muscle and the myocardium. The time of appearance of the second wave of rise gamma-counting in blood samples from coronary sinus reflects the repeated entry of radiopharmaceutical in myocardium after recirculation.

[The use of a new method for determining the ratio of the glomerular filtration rate to circulating plasma volume in patients with arterial hypertension]. / Primenenie novogo metoda opredeleniia otnosheniia skorosti klubochkovoi fil'tratsii k ob''emu tsirkuliruiushchei plazmy u bol'nykh arterial'noi gipertoniei.

Renal scintigrams with 99Tc-DTPA were analysed retrospectively in 19 patients with essential hypertension. Glomerular filtration rate (GFR) was measured by Gates technique. Ratio GFR to plasma volume (PV) was quantified by A. M. Peters' technique (1994). PV was calculated as the relation of these two indices. Total GFR in hypertensive patients widely ranged (from 76.8 ml/min to 165.7 ml/min). Three groups were selected taking into account hypertension duration: patients with decreased, normal and increased values of basal GFR. The severity of hypertension did not affect the GFR, but showed positive and strong correlation with PV (r = 0.91; p < 0.05). GFR/PV was decreased in hypertensive patients. Factors affecting the GFR in hypertensive subjects are discussed.

[Opioid peptides in the dynamics of "physiological" and "pathological" stress]. / Opioidnye peptidy v dinamike "fiziologicheskogo" i "patologicheskogo" stressa.

Clinical studies showed that short-term "physiological" stress (bicycle ergometry) did not cause increase of the blood plasma enkephalin content. Moderate-term (60-minute) stress, according to O. Desiderato, causes a rise of the blood enkephalin level in rats. It is supposed that such a reaction of the opioid system is characteristic of borderline conditions between normal and pathological states in stress. Severe "pathological" stress (myocardial infarction, experimental coronary occlusion, 6-hour stress after O. Desiderato) in rats led to a decrease of the concentration of enkephalins in the blood and disorders of their secretion and storage in the adrenals. It is suggested that changes of the activity of the opioid system are a predictor of the transition of a "physiological" stress to a "pathological" stress.

[199Tl chloride in the experimental assessment of myocardial perfusion. 2]. / 199Tl-khlorid v otsenkie perfuzii miokarda v ésperimente. Soobshchenie 2.

Pharmacokinetic and scintigraphic studies on 199Tl were conducted. Pharmacokinetic characteristics of 199Tl chloride give an opportunity to use it for perfusion scintigraphy of the myocardium which is no inferior in the resolving power to 201T1. The shorter half-life of 199Tl will make it possible to reduce radiation exposure of an examinee.

[Spectrometric characteristics and phantom studies of 199Tl]. / Spektrometricheskie kharakteristiki i fantomnye issledovaniia 199Tl.

Spectrometric phantom studies on 199Tl were conducted. They showed that for this radionuclide low-energy parallel collimators should be used, the peak of a differential discriminator being adjusted to 72 keV. Image resolution of this radionuclide was no inferior to that of the commonly used radionuclide 99mTc.

[Tomoscintigraphic characteristics of the basic types of incorporation of 99mTc-pyrophosphate in the "myocardium" (phantom studies)]. / Tomostsintigraficheskie kharakteristiki osnovnykh tipov vkliucheniia 99mTc-pirofosfata v "miokard" (fantomnye issledovaniia).

The results of phantom studies have shown that tomoscintigraphy makes it possible to define the localization and size of RP diffuse incorporation in the "myocardium" and to differentiate between true and false-positive results. A rarefaction in the center of an image obtained on a transverse tomographic section should be regarded as a characteristic feature of true RP diffuse incorporations.

[Experimental perfusion scintigraphy of the myocardium using 199Tl chloride]. / Perfuzionnaia stsintigrafiia miokarda s 199Tl-khloridom v éksperimente.

The authors conducted phantom, pharmacokinetic and scintigraphic investigation of the radionuclide thallium-199. It was shown that the spectrum of x-rays permitted good imaging of the phantom on photon energy peaks of 72 keV using a scintillation camera with a standard high resolution collimator. The physiochemical and pharmacokinetic characteristics of the radionuclide give an opportunity to use it for perfusion scintigraphy of the myocardium.