Attempt of quantitative analysis of visual evaluation for (123)I-BMIPP myocardial scintigraphy images.

We developed a new technique to quantitatively analyze visual evaluation single photon emission computed tomography (SPECT). Short axis tomograms and color scales were computer scanned. The scales were divided into 25 parts; numbers of each hue pixel were scored 0-100%. Short-axis images were divided into eight equal partitions, numbers of hue pixels distributed in each partition were scored, and total scores were obtained. Each partition's radio-isotope (RI) accumulation index was calculated as partition score/highest score. For method validation, scintigrams from each left ventricular phantom part were divided into eight partitions and filled with (123)I-BMPP (10-100%). The error between theoretical and calculated concentrations was within 20% in the concentration range of ≥50%, suggesting a good correlation and indicating the method's validity.

Evaluation of carotid atherosclerosis from the perspective of blood flow reflection.

Detection and prevention of atherosclerosis at an early stage is important for its prevention. The aim of this study was to propose a valid and highly reliable index for the evaluation of carotid atherosclerosis or carotid function. Images of carotid Doppler wave profiles were processed using an image processing software, and the relative fluctuation in blood flow was calculated from the luminance in one cardiac cycle. Frequency analysis was performed and up to 10 time components of basic frequency (f1) were indicated. The evaluation function alpha was estimated by calculating the ratio of the sum of components f3-f10 against the f1 + f2 components. Blood pressure of the finger was continuously measured using Finapress during passive postural change from the supine to the standing position, the baroreceptor function was evaluated by the frequency method, and the plaque score was measured by ultrasound tomography. The influence of factors such as arterial compliance, blood vessel resistance, and heart rate on this index was studied using electric circuit model simulation. The subjects were 33 patients (18 men, 15 women) who had various types of atherosclerotic disease and hypertension. The average age was 67.3 + 12.2 years. The results showed that index alpha had a strong negative correlation with age and plaque score, and a weak positive correlation with baroreceptor function. Simulation results supported the clinical result. We proposed a new index to evaluate carotid atherosclerosis without blood pressure measurement using the carotid Doppler method. It is a potential index for detecting atherosclerosis of local arteries such as the carotid.

Involvement of carotid baroreceptor function in blood pressure control in the chronic phase: effect on 24-hour ambulatory blood pressure.

BACKGROUND: It is generally thought that the sole function of baroreceptors is for the regulation of rapid blood pressure fluctuations caused by postural changes and other motion. However, recent studies have suggested that baroreceptors may also be involved in blood pressure control in the chronic phase. PURPOSE: The study was performed to examine the involvement of carotid baroreceptors in blood pressure control in the chronic phase, through determination of the relationship between 24-hour blood pressure data and carotid baroreceptor function. METHODS: Ambulatory blood pressure, ECG, and the number of steps during exercise were measured every 15 minutes with an ambulatory blood pressure monitor and a 24-hour Holter ECG fitted with an accelerometer (Cardy-II-p, Suzuken KK, Japan). In addition, the dependence of blood pressure on autonomic nerve activity and exercise was analyzed based on the frequency of the RR interval. Patients were divided into three groups based on different blood-pressure types: autonomic nerve-dependent, exercise-dependent, and independent types. Carotid baroreceptor function was evaluated using the sequence method; subjects adopted a supine position on a tilt table and their arterial pressure was monitored continuously using a Finapress finger cuff (Finapress, Ohmeda, Louisville, Colorado, USA). The study was performed in 90 patients, including 42 with essential hypertension whose blood pressure was well controlled. RESULTS AND CONCLUSIONS: A significant negative correlation was found between the mean 24-hour blood pressure and baroreceptor function for both systolic and diastolic pressure. Systolic pressure in patients of the independent type was significantly higher than that in patients of the exercise-dependent type. Furthermore, non-dipper hypertension was noted more frequently and baroreceptor function was significantly lower in independent-type patients, compared with autonomic nerve-dependent and exercise-dependent types, suggesting that independent-type blood pressure may be due to baroreceptor dysfunction. In conclusion, our results suggest that baroreceptor function might be involved in blood pressure control in the chronic phase, and baroreceptor dysfunction may contribute to the development of essential hypertension.