Bifurcation in blood oscillatory rhythms for patients with ischemic stroke:a small scale clinical trial using laser Doppler flowmetry and computational modelling of vasomotion

We describe application of spectral analysis of laser Doppler flowmetry (LDF) signals to investigation of cerebrovascular haemodynamics in patients with post-acute ischemic stroke (AIS) and cerebrovascular insufficiency. LDF was performed from 3 to 7 days after the onset of AIS on forehead in the right and left supraorbital regions in patients. Analysis of LDF signals showed that perfusion in the microvasculature in AIS patients was lower than that in patients with cerebrovascular insufficiency. As a result of wavelet analysis of the LDF signals we obtained activation of the vasomotion in the frequency range of myogenic oscillation of 0.1 Hz and predominantly nutritive regime microcirculation after systemic thrombolytic therapy of the AIS patients. In case of significant stroke size, myogenic activity and nutritive pattern microhaemodynamics were reduced, in some cases non-nutritive pattern and/or venular stasis was revealed. Wavelet analysis of the LDF signals also showed asymmetry in wavelet spectra of the LDF signals obtained in stroke-affected and unaffected hemispheres in the AIS patients. A mechanism underlying the observed asymmetry was analysed by computational modelling of vasomotion developed in (Arciero & Secomb, 2012). We applied this model to describe relaxation oscillation of arteriole diameter which is forced by myogenic oscillation induced by synchronous calcium oscillation in vascular smooth muscle cells. Calculation showed that vasomotion frequency spectrum at the low-frequency range (0.01 Hz) is reciprocally modulated by myogenic oscillation (0.1 Hz) that correlates with experimental observation of inter-hemispheric variation in the LDF spectrum

Ultrasound diagnostics of a spontaneous arteriovenous fistula of the head and neck

An arteriovenous fistula is an abnormal connection between the arterial and venous systems. In the literature, there are well-described ultrasound findings of iatrogenic arteriovenous fis­tula as a potential complication from percutaneous transarterial or transvenous procedures. The most important sign is direct visualization of the fistula in the place of the access site. It is necessary to look for secondary signs of arterialization of the veins, which can suggest a diagnosis of an arteriovenous fistula. However, the accuracy and diagnostic quality of duplex scanning in the diagnostics of a congenital or spontaneous arteriovenous fistula of the head and neck area in adults have been poorly described in the literature. In this study, we discuss the opportunities of duplex scanning, based on two different cases of an arteriovenous fistula revealed by ultrasound and then confirmed by computer tomographic angiography

Diagnostyka ultrasonograficzna spontanicznych przetok tętniczo-żylnych w rejonie głowy i szyi

An arteriovenous fistula is an abnormal connection between the arterial and venous systems. In the literature, there are well-described ultrasound findings of iatrogenic arteriovenous fistula as a potential complication from percutaneous transarterial or transvenous procedures. The most important sign is direct visualization of the fistula in the place of the access site. It is necessary to look for secondary signs of arterialization of the veins, which can suggest a diagnosis of an arteriovenous fistula. However, the accuracy and diagnostic quality of duplex scanning in the diagnostics of a congenital or spontaneous arteriovenous fistula of the head and neck area in adults have been poorly described in the literature. In this study, we discuss the opportunities of duplex scanning, based on two different cases of an arteriovenous fistula revealed by ultrasound and then confirmed by computer tomographic angiography.Przetoka tętniczo-żylna jest niefizjologicznym połączeniem wytworzonym pomiędzy układem tętniczym a żylnym. W piśmiennictwie znaleźć można dobrze opisane przypadki jatrogennych przetok tętniczo-żylnych będących powikłaniem przezskórnych zabiegów wewnątrznaczyniowych. Najważniejszym objawem jest bezpośrednie uwidocznienie przetoki w miejscu dostępu. Należy szukać wtórnych objawów arterializacji żył, mogących sugerować istnienie przetoki tętniczo-żylnej. Dokładność i jakość obrazowania przetoki w badaniu ultrasonograficznym metodą duplex-scan w diagnostyce wrodzonych i spontanicznych przetok tętniczo-żylnych głowy i szyi u dorosłych nie zostały dostatecznie opisane w literaturze. W niniejszej pracy omawiamy możliwości badania duplex-scan w tejże diagnostyce na podstawie dwóch różnych przypadków przetoki tętniczo-żylnej, ujawnionej w badaniu ultrasonograficznym, a następnie potwierdzonej w angiografii tomografii komputerowej. Artykuł w wersji polskojęzycznej jest dostępny na stronie http://jultrason.pl/index.php/wydawnictwa/volume-17-no-7