Importance of angle correction in transcranial color-coded duplex insonation of arteries at the base of the brain.

BACKGROUND/AIM: Transcranial color-coded duplex (TCCD) sonography allows visualization of the vessels being examined and measurement of the angle of insonation. The published literature suggests that blood vessels are insonated at the angle lower than 30 degrees, hence no correction for the angle is necessary. The aim of this study was to determine the availability of intracranial blood vessels for insonation, and the percentage of arteries and their segments which can be insonated at the angles lower than 30 degrees. METHODS: The study included 120 patients (mean age 51). For each of the segments the angle of insonation was registered based on TCCD vizualization, and hemodynamic parameters were measured. The angle of insonation was measured using combined B-mode and color Doppler vizualization, as the angle between the direction of the ultrasound beam and the axis of the shown arterial segment. RESULTS: The total success rate of insonation was 86.33% (1,554 out of 1,800). The mean angle of insonation value in all the examined arterial segments was 42 degrees. The insonation angle was higher than 30 degrees in about three quarters of the examined segments, especially in the A2 segment of the anterior cerebral artery (98%), the P1 segmet of the posterior cerebral artery (87%) and in the terminal internal carotid artery (83%). The A1 segment of the anterior cerebral artery showed the best insonation conditions with the angle of insonation lower than 30 degrees in 53% of the cases. CONCLUSION: The presented results of angles of insonation measurements for the anterior, middle and posterior cerebral arteries and their segments, as well as the terminal portion of the internal carotid artery clearly indicate that their average values in tested segments were very often higher than 30 degrees, which can cause an error in blood flow velocity measurement that cannot be ignored. The results confirm the necessity of correcting flow velocity values on the basis of the angle of insonation in TCCD sonography.

[Intimomedial thickness of the vertebral arteries complex: a new useful parameter for the assessment of atheroclerotic process?].

BACKGROUND/AIM: An integral part of Doppler ultrasound examination of cervical blood vessels is determination of intimomedial thicknes (IMT) of the common carotid. The aim of the study was to estimate the relations between IMT of the common carotid and vertebral arteries in order to determine if the value of IMT obtained on the vertebral artery could be applied in clinical practice. METHODS: We measured IMT in a randomized, prospective and cross-sectional study, performed on 50 persons both sexes (29 men and 21 women), at the age from 18 to 79 years (mean age 52.4 +/- 17.63 years). All the persons were healthy, what was confirmed with clinical examination and laboratory analyses. Measurements were perfomed from January 2006 until September 2008. Intimomedial thickness was recorded by two dimensional ultrasonography in B-mode on both common carotid arteries: one value was obtained as average of three successeful measurements (measurements were perform on different places). We measured IMT on the first segment of both vertebral arteries, 1.5 cm proximal from the connection of the first and second segments (we got results of the measurement of IMT on the vertebral arteries in the same way: mean value from the three records). RESULTS: The measured value of IMT on the common carotid arteries (IMT = 0.782 +/- 0.248 mm), obtained from 50 healthy persons, was higher than that measured on the vertabral artery on the first segment (IMT = 0.585 +/- 0.134 mm). The values of IMT after measurement on two different places were statistically highly different (t = 7.03, SD = 0.028, p < 0.01). Coefficient of variability of IMT values in carotid circulation (CV = 34.4%) was higher than that in vertebral circulation (22.9%). Values of IMT on vertebral arteries were in statistically significant correlation with those in carotid circulation (r = 0.24 and t- = 2.48; p < 0.02). There were no statistically significant difference between IMT measurement on the right and the left side so they were analysed as the same set. CONCLUSION: Values of IMT on the vertebral arteries are one more undependent parameter of Doppler-sonographic examination of cervical vessels, which significantly correlates with IMT values on common carotid artery. Variability of this parameter is lower, and absolute values lower than the same in the common carotid artery. Therefore, this parameter is probably not so sensitive. On the other hand, lower variability of IMT values on the vertebral artery might be of higher specificity for prediction of atherosclerotic progress by the increased values of this parameter than based on IMT values obtained on the common carotid arteries.

[Predictive value of changes in the hemostasis system in patients with ischemic brain diseases]. / Prediktivna vrijednost promjena u hemostaznom sistemu kod bolesnika sa ishemijskom bolescu mozga.

The aim of this research was to determine the importance of tracking the dynamics of changes of the hemostatic system factors (aggregation of thrombocytes, D-dimer, PAI-1, antithrombin III, protein C and protein S, factor VII and factor VIII, fibrin degradation products, euglobulin test and th activated partial thromboplastin time--aPTPV) in relation to the level of the severity of ischaemic brain disorders (IBD) and the level of neurological and functional deficiency in the beginning of IBD manifestation from 7 to 10 days, 19 to 21 day, and after 3 to 6 months. The research results confirmed significant predictive value of changes of hemostatic system with the predomination of procoagulant factors, together with the insufficiency of fibrinolisys. Concerning the IBD severity and it's outcome, the significant predictive value was shown in the higher levels of PAI-1 and the lower level of antithrombin III, and borderline significant value was shown in the accelerated aggregation of thrombocytes and the increased concentration of D-dimer. It could be concluded that the tracking of the dynamics of changes in parameters of hemostatic system proved to be an easily accessible method with the significant predictive value regarding the development of more severe. IBD cases and the outcome of the disease itself.