Mechanical Dyssynchrony and Microvascular Dysfunction by SPECT

"All nuclear examinations will be performed using a hybrid specialized SPECT/CT Discovery NM/CT570C. At the first stage the passage of the bolus of the radiopharmaceutical through the chambers and the LV myocardium will be recorded at rest. Through a pre-installed intravenous catheter, a bolus of the radiopharmaceutical in a volume of 5 ml (370 MBq) will be injected at a rate of 0,5 ml/sec, after which 30 ml of saline will be injected at a rate of 2 ml/sec. Data acquisition will begin immediately before the introduction of the radiopharmaceutical. Registration of dynamic images will be performed in the List Mode.~At the second day stress test study will be performed (ATP at a dosage of 160 mcg/kg/min over 4 minutes). The bolus volume of the radiopharmaceutical, saline and the rate are equal to the study at rest. The time of data collection at each stage of the study will be 12 minutes. The introduction of the radiopharmaceutical will be performed at 2 minutes of the stress test."

"Gated MPI will be performed according to a two-day rest-stress protocol. For both stress and rest studies, the acquisition will be performed 60 minutes after the dynamic SPECT. The recording time will be 5 minutes. To correct the attenuation, a low-dose CT scan of the chest, obtained earlier with dynamic recording, will be used. The voltage on the X-ray tube will be 120 kV, the current strength will be 20 mA; tube rotation time 0.8 s; pitch 0.969:1. Radiopharmaceutical administration will be performed only once a day during dynamic SPECT.~Immediately after recording the gMPI at rest, the patient will undergo a series of sequential injections of dobutamine at doses of 5 and 10 µg/kg/min with simultaneous recording. The duration of data collection on each dose of dobutamine will be 5 minutes."

"Indicators of:~* endothelial dysfunction (specific endothelial cell molecule 1 (endocan, ESM1), endotelin-1)~* severity of inflammatory response (tumor necrosis factor (TNF-α), interleukin-6 (IL-6))~* myocardial fibrosis (matrix metalloproteinase (MMP-9)~* myocardial dysfunction (NT-proBNP)"

Scanning parameters: tube voltage 120 kV; current 435 mA; tube rotation time 0.4 s; slice thickness 2.5 mm; interslice interval 2.5 mm.

The study will be performed on a 64-slice GE Discovery NM/CT 570С (GE Healthcare, Milwaukee, WI, USA) from the level of the tracheal bifurcation to the diaphragm during breath holding (6-8 s) in the prospective (for HR≤55) or retrospective (for HR\>55) ECG-synchronized mode. To contrast coronary arteries, it is planned to use an intravenous infusion of 85-90 ml (at a rate of 5 ml/s) of an iodine-containing (370 mg iodine/ml) radiopaque substance.Scan will be performed with the following parameters: current strength 120 kV; voltage 300-600 mA with ECG modulation; tube rotation speed 0.4 s; pitch: 0.18-0.22 (depending on heart rate).