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The brain infarct core delineation using computed tomography angiography source images in acute stroke patients
Rohan, Vladimír ; Choc, Milan (advisor) ; Kalvach, Pavel (referee) ; Kalita, Zbyněk (referee) ; Smrčka, Martin (referee)
Background and Purpose: Ischemic stroke is the 3rd most common cause of death and most common cause of permanent disability in developed countries. Rapid diagnostic work-up with reliable assessment of infarcted brain tissue and potentionally salvageable brain tissue is critical for acute stroke management. The first aim of this study is to asses delineation of infarct core in acute stroke patients using whole brain perfused blood volume (PBV) maps. These maps are calculated by automatic processing from computed tomography angiography source images (CTA-SI) and non-contrast computed tomography (NCCT) data. The second aim is to determine optimal quantitative threshold of PBV for infarct core identification in acute stroke setting. Material and methods: PBV maps were constructed using prototype software from NCCT and CTA-SI data in 37 acute ischemic stroke patients with angiographically proved recanalization after intravenous thrombolytic treatment. These PBV maps were automatically compared with final infarct extension on follow-up NCCT. The anatomic pixel-by-pixel correlation was assessed using Matthew's correlation coefficient (MCC) for infarct core delineation using different critical values of PBV. The optimal threshold with the best correlation was used for infarct volume computation. Minimal PBV...
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Magnetic resonance imaging of central nervous system lymphoma.
Koubská, Eva ; Malíková, Hana (advisor) ; Kalvach, Pavel (referee) ; Druga, Rastislav (referee)
Background: The aim of this study was to describe the morphological signs of the central nervous system lymphoma (CNSL) in magnetic resonance imaging (MRI). We compared morphological characteristics of primary CNSL (PCNSL) and secondary CNSL (SCNSL) and also of PCNSL and glioblastoma (GBM). Methods: We included 64 patients with PCNSL (ten of them were immunocompromised), 21 patients with SCNSL and 54 patients with GBM. The diagnosis was confirmed histologically in all patients. We evaluated morphological signs on the first MRI examination. Additionally, in patients with PCNSL, we evaluated the development of the disease on follow-up examination before histological confirmation of the diagnosis, if available. Results: In most patients with PCNSL (62.5%) the tumor was localized supratentorially and presented as multiple lesions (53.1%) or as a diffuse infiltrative lesion (23.4%). In 87.5% of the patients the lesions reached the brain surface. Infiltration of ependyma was seen in 56.3%, infiltration of meninges in 39.1% and infiltration of cranial nerves in 48.5% of patients. Restriction of diffusion in some part of the tumor was apparent in nearly all patients (97.6%) with PCNSL. After administration of contrast media, marked enhancement was usually seen. In immunocompetent patients, homogenous...
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Possibilities of aggregometry in antiplatelet prevention of strokes. Relationship between reduced aggregation and stroke risk prevention.
Chýlová, Miroslava ; Kalvach, Pavel (advisor) ; Tomek, Aleš (referee) ; Herzig, Roman (referee)
Background. This dissertation offers an overview of knowledge about platelets, the principle of platelet aggregation, its reduction by antiplatelet drugs and anticoagulation, methods of measuring platelet aggregation and views on resistance to acetylsalicylic acid. The effectiveness of ASA (acetylsalicylic acid) in prevention of vascular events is usually derived indirectly from comparison of individuals taking placebo and not from the results of aggregometric methods. The purpose of our work was 1) to assess the effect of different doses and different routes of ASA administration on platelet aggregation, 2) to compare results of two different aggregometry methods and 3) to assess the effect of anticoagulation treatment on platelet aggregation in patients with chronic ischemic heart disease. Methods. The first study group consisted of 22 healthy individuals and 30 patients with documented ischemic stroke. Platelet aggregation was measured before ASA application and then after different doses and different routes of ASA administration. In the second study the group consisted of 30 patients with documented ischemic stroke who were taking orally 100mg ASA daily. We compared platelet aggregation measured by VerifyNow and by light transmission aggregometry (LTA) using different agonists. In the third...
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Hemodynamic parameters of the cervical carotid bed of saline in the throes of stenosis of the carotid bulb and the bed capacity of treated recanalization excercise
Gregová, Daniela ; Kalvach, Pavel (advisor) ; Zvěřina, Eduard (referee) ; Beneš, Vladimír (referee) ; Bauer, Jiří (referee)
With the increasing number of patients suffering from some metabolic diseases leading to the development of atherosclerosis there is an urgent need for early diagnosis of the scale. If we think about disability sclerotic cerebral arteries, the optimal method of investigation is duplex ultrasonography, which is relatively inexpensive and friendly for the patient. To assess not only the structure and extent of atherosclerotic plaque, but also to assess the extent of any narrowing of the arteries and to evaluate the hemodynamic impact of structural changes present. It is an ideal candidate for screening in primary or secondary prevention of stroke, as well as for regular checks dispensarized patients. Knowledge of normal hemodynamic conditions in the cervical carotid stream is necessary in the assessment of various pathological conditions. This paper seeks to offer the most comprehensive view on the issue of carotid stenoses ultrasonografisty eyes. For practical reasons we focus on localized stenosis in the carotid bulb, the number is high above the stenosis in other locations.
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Diffusion Weighted Imaging and Other Quantitative MRI Methods in the Diagnostics of Selected CNS Diseases
Keller, Jiří ; Kalvach, Pavel (advisor) ; Hluštík, Petr (referee) ; Hájek, Milan (referee)
The aim of this study was to assess the scope of exploitation of the diffusion weighted imaging and other quantitative MR methods in the clinical diagnostics. We calculated the normal values of fractional an- isotropy (FA) in our group of healthy volunteers and proved FA depen- dence on age in some regions of brain using regression analysis. The relationship was quadratic in the splenium of callosal body, the left pre- central gyrus and in the pyramidal tract at the level of mesencephalon on the right. Linear decrease of FA with age was found in the rostrum of callosal body, in the white matter of frontal lobes, in the anterior limb of internal capsule on both sides and in the pyramidal tract at the level of mesencephalon on the left. In all measured parts of basal ganglia FA in- creased. Based on our data set, we propose a non-linear colour look-up table (LUT) to enhance the pathologic values. The use of this LUT is presented in patients with several neurological disorders. Quantitative methods were used also for assessment of the group of patients suffering from ALS. The changes we expected in the posterior limb of internal capsule were not significant, therefore we suppose that the presence of T2 hyperintensity in this region is not a reliable marker of the disease. T2 relaxometry detected the...
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Age dependent decrease of cerebro-vascular reactivity and its impact on brain parenchyme integrity
Peisker, Tomáš ; Kalvach, Pavel (advisor) ; Zvěřina, Eduard (referee) ; Hort, Jakub (referee)
Summary: Sufficient vasodilatory and vasoconstrictive reactivity of cerebral arterioles is an important prerequisite for adequate capillary perfusion. To appreciate its capacity during aging and to elucidate its impact on parenchymal integrity we undertook a correlation using ultrasonography and brain MRI. Sixty healthy persons with no stenoses in carotid and vertebral arteries were examined by transcranial doppler ultrasonography (TCD) to assess middle cerebral artery mean flow velocities (MFV) et rest, after 30 sec apnea and after 90 sec hyperventilation. Young persons, N=20, mean age 24,8 (20- 32) were compared with middle aged, N=20, 54,8 (40-63) and elderly, N=20, 76,2 (69-84). A cohort of 40 elderly persons, mean age 68,4 (57-85) were evaluated also by MRI using FLAIR and T2-weighted sequences. Their extent of leukoaraiosis measured by the Fazekas scale was correlated with their vasoregulatory capacity. Results: The steady state mean flow velocity (MFV) in young persons, 71 cm/sec, decreases to 48,1 and to 44,9 cm/sec in the middle and the old aged. The postapnoic vasodilatation in young persons accelerates the MCA blood velocity by 41,7%, while in middle and old age only by 37,9 and 32,7% respectively. The MCA deceleration post hyperventilation by 49,8% in young people decreases to 37,8% and to 29,7%...
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A comparison of various systems of urgent care and their future directions
Pokorný, Jiří ; Čelko, Alexander (advisor) ; Kalvach, Pavel (referee) ; Špunda, Jan (referee)
While a relatively young field of medicine, emergency care (EC) has recently witnessed dramatic advances which will definitely continue. At present, there are 2 main systems of EC provision, the Anglo-American and the Franco-German ones. Both systems have their indisputable advantages; however, they are also fraught with major drawbacks. Given my long-term personal experience with emergency medical service as well as my appointments in hospital resuscitation wards, emergency departments, and operating theaters, I am convinced there is still considerable room for improvement in the organization of pre- and in-hospital EC in our country. To develop this thesis, I have collected as much as possible information about the organization of EC in various countries of the world and in the CR. Based on my knowledge and data from the above sources and, also, using my long-standing experience, I have evaluated and compared individual EC systems assessing both their advantages and disadvantages. The analysis has shown that the system of EC should meet both the geopolitical and economic status of the country involved, and the standard of currently available therapeutic options. The outcome of my study is a proposal to modify the system of EC in the CR. It should be an adaptable system, with its main advantage being it...
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Ischemic strokes in vertebrobasilar region, caused by lesions of magistral arteries
Škoda, Ondřej ; Kalvach, Pavel (advisor) ; Šonka, Karel (referee) ; Kemlink, David (referee)
Vertebrobasilar ischemic strokes, caused by lesions of magistral arteries. Background and Purpose Progress in modern non-invasive or minimally invasive diagnostic methods has improved detection and evaluation of pathological changes in the vertebral arterial system. Ischemia in vertebrobasilar circulation, often caused by stenotic processes of vertebral arteries, is considered a severe form of stroke, with a mortality of 20 - 30%. Stenoses of these arteries may be responsible for up to one half of ischemic events in their nutritive region. Although there is no general consensus on treatment of the VA stenoses so far, recent recommendations consider interventions in secondary stroke prevention, when optimal conservative treatment did not prevent recurrent clinical symptoms. With the increasing number of centers providing diagnostics and possible interventional treatment, the objective assessment of these lesions should be available. However, due to a relatively small part of patients, who are indicated to vertebral angioplasty, the diagnostic procedures should be as noninvasive and safe, as possible. The aim of this study was to create the accurate, noninvasive an safe diagnostic algorithm for the detection and evaluation of the VA stenoses and to test its reliability on our own patients group....
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