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Time-resolved near-infrared spectroscopy in monitoring acute ischemic stroke patients - Case study

Kuls-Oszmaniec Aleksandra, Kacprzak Michał, Morawiec Magdalena, Sawosz Piotr, Fiszer Urszula, Leńska-Mieciek Marta

Biocybernetics and Biomedical Engineering

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2024

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Vol. 44, no. 1

149--160

EN

Stroke is a leading cause of disability and death worldwide, with acute ischemic stroke (AIS) accounting for the majority of cases. Early and accurate diagnosis of AIS is crucial for improving patient outcomes. Non-invasive monitoring techniques, such as time domain near-infrared spectroscopy (tdNIRS), have shown potential for real-time monitoring of AIS patients at the bedside. However, there is a need for further research to evaluate the effectiveness of tdNIRS in the acute phase of stroke. In this study, we present the results of a case report using tdNIRS to monitor AIS patients without any additional stimulation. The tdNIRS technique allows for noninvasively assessing cerebral oxygenation in absolute units, enabling accurate measurement of changes in oxygenated and deoxygenated hemoglobin concentrations in the brain. Our aim was to determine the feasibility of tdNIRS in monitoring AIS patients.

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Metody obrazowania udaru niedokrwiennego mózgu w fazie ostrej

Kidoń Joanna, Lasek-Bal Anetta

Inżynier i Fizyk Medyczny

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2022

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Vol. 11, nr 5

407--412

PL

Udar mózgu stanowi jedną z wiodących przyczyn niepełnosprawności oraz śmierci na świecie. Pomimo spadku śmiertelności z powodu udaru mózgu, globalne obciążenie udarem wzrasta. Udar niedokrwienny charakteryzuje niejednorodny patomechanizm, począwszy od obrzęku cytotoksycznego (minuty od wystąpienia incydentu mózgowo-naczyniowego), obrzęku naczyniopochodnego (od 6 godzin), po procesy naprawcze (neuroangiogeneza, neurogeneza) w fazie podostrej i przewlekłej. Do podstawowych technik obrazowania udaru niedokrwiennego mózgu zaliczyć należy przede wszystkim tomografię komputerową (celem wyeliminowania ewentualnego krwawienia, innych przyczyn pogorszonego stanu neurologicznego), rezonans magnetyczny (techniki: dyfuzyjne, saturujące sygnał płynu mózgowo-rdzeniowego, podstawowe, podatności magnetycznej), angiografię (CT, MRI, DSA) oraz ultrasonografię. Techniki dyfuzyjne oraz perfuzyjne (CT, MRI, SPECT, PET) służą do oceny rozległości strefy półcienia. Techniki dyfuzyjne mają szczególne znaczenie w ocenie czasu wystąpienia incydentu mózgowo- naczyniowego. Uważa się, że DWI poprawia wykrywalność udarów niedokrwiennych mózgu aż do 95% w porównaniu ze standardowymi technikami obrazowania. Korelacja map ADC i obrazów DWI pozwala zidentyfikować obszary niedokrwienia. W obrazach DWI sygnał jest hiperintensywny w ciągu kilku minut od incydentu zawałowego, natomiast ADC wykazuje obniżone wartości w czasie od pierwszego do czwartego dnia, w piątej do dziesiątej dobie ma miejsce ich wzrost, po czym następuje wyrównanie względem tkanki zdrowej.

EN

Stroke is one of the leading causes of disability and death in the world. Despite the decline in stroke mortality, the global burden of stroke is increasing. Ischemic stroke is characterized by a heterogeneous pathomechanism, ranging from cytotoxic edema (minutes from the occurrence of a cerebrovascular accident), vasogenic edema (from 6 hours), to repair processes (neuroangiogenesis, neurogenesis) in the subacute and chronic phases. The basic techniques of ischemic stroke imaging include, first of all, computed tomography (to eliminate possible bleeding, other causes of deteriorated neurological condition), magnetic resonance (techniques: diffusion, saturating the cerebrospinal fluid signal, basic, magnetic susceptibility), angiography (CT, MRI, DSA) and ultrasound. Diffusion and perfusion techniques (CT, MRI, SPECT, PET) are used to assess the extent of the penumbra. Diffusion techniques are of particular importance in assessing the timing of a cerebrovascular accident. DWI is believed to improve the detection of ischemic strokes by up to 95% compared to standard imaging techniques. Correlation of ADC maps and DWI images identifies ischemic areas. In DWI images the signal is hyperintense within a few minutes of the infarction incident, while the ADC shows decreased values from the first to the fourth day, on the fifth to the tenth day their increase takes place, followed by compensation for healthy tissue.

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Numerical simulation of non-linear loading– unloading hysteresis behavior of blood clots

Tashiro Koichiro, Shobayashi Yasuhiro, Hotta Atsushi

Biocybernetics and Biomedical Engineering

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2022

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Vol. 42, no. 4

1205--1217

EN

The stress-strain characteristics of a clot during loading/unloading mechanical cycles are significant features to assess the underlying mechanisms of thrombectomy, especially when multiple thrombectomy attempts are required. We investigated a damage model to predict loading/unloading response of clots. To study the validity of the model, we tested theoretical models to reproduce the experimentally obtained mechanical characteristics of clots under various conditions. Three types of clot analogs with different red blood cell (RBC) compositions were prepared. Cylindrical clot analogs were formed for the tensile and compression tests. Loading/unloading tests at 80% of strain were conducted, where the material parameters were determined by fitting the results to a theoretical curve combining the damage model and the elasto-plastic constitutive model. Through the computation for theoretical curves, unique characteristics of clots were revealed such that the hysteresis loss rate did not change by varying RBC contents, except for the clot created with 0% RBC composition, under compressive loading. In addition, the plastic strain decreased as the RBC content decreased under tensile loading, whereas it increased as the RBC content decreased under compressive loading. A three-dimensional finite element method (FEM) was employed with the determined parameters. The FEM could accurately reproduce the experimental stress-strain curves for all types of clot analogs and for both loading types up to a strain of 80%. The results indicate that the theoretical model which incorporates and combines the damage model and the elasto-plastic constitutive model is applicable to predict the non-linear stress–strain behavior of clots under loading and unloading.

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Ocena skuteczności ćwiczeń kończyny górnej, wykonywanych w przestrzeni wirtualnej przy zastosowaniu biologicznego sprzężenia zwrotnego, u pacjentów po udarze niedokrwiennym mózgu – doniesienia wstępne

Wieczorek Michał, Makuch Maciej

Aktualne Problemy Biomechaniki

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2019

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z. 17

123--130

PL

Celem badań była ocena wpływu programu rehabilitacji pacjentów po udarze na funkcjonalność, motorykę, zakresy ruchomości oraz wartości siły kończyny górnej, uzupełnionego o ćwiczenia w przestrzeni wirtualnej oraz porównanie osiągniętych wyników z grupą kontrolną. Do oceny stanu funkcjonalnego pacjentów użyto testów Fugl-Mayer Motor Assessment, Frenchy Arm Test oraz skali Lovetta. Dokonano pomiarów zakresu ruchomości w stawach barkowym, promieniowo-nadgarstkowym (płaszczyzny: czołowa i strzałkowa), łokciowym, jak również zmierzono wartości siły chwytów: cylindrycznego, szczypcowego, bocznego i trójpunktowego.

EN

The aim of the study was to assess the impact of post-stroke rehabilitation program on functionality, motor skills, mobility ranges and upper limb strength values, supplemented with VR exercises and comparison of the results obtained with the control group. The Fugl-Mayer Motor Assessment, the Frenchy Arm Test and the Lovett scale were used to assess the functional status of the patients. Measurements of the range of motion in shoulder, radial-wrist joints (planes: frontal and sagittal) and elbow were measured, as well as the values of grip strength: cylindrical, pincer, lateral and three-point.

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Multiscale extraction of diagnostic content applied for CT brain examination

Przelaskowski A., Ostrek G., Sklinda K.

Biocybernetics and Biomedical Engineering

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2009

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Vol. 29, no. 4

25-40

EN

This paper presents the estimation methods of subtle hypodense changes of brain tissue in noncontrast CT scans. The purpose of reported research is improved detection of direct signs of hyperacute ischemic stroke. Proposed tool is nonlinear approximation in base of multiscale functions with respective thresholding. Different rationales for best basis selection were considered. Several local bases including wavelets, curvelets, contourlets and wedgelets were considered and characterized with a criterion of as fast as possible approximation error decay. Adaptive thresholding was suggested for defining of nonlinear approximation space for different image models. Procedures of estimation and extraction of diagnostic information were experimentally verified. Improved diagnosis of acute stroke eases was reported.