Publications by authors named "Jernej Vidmar"

Objectives: The aim of our study was to assess the correlation between T relaxation times and their variability with the histopathological results of the same teeth in relation to caries progression.

Materials And Methods: 52 extracted permanent premolars were included in the study. Prior to extractions, patients underwent magnetic resonance imaging (MRI) scanning and teeth were evaluated using ICDAS classification.

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Background: Computer-aided diagnosis (, texture analyses) tools are becoming increasingly beneficial methods to monitor subtle tissue changes. The aim of this pilot study was to investigate short-term effect of platelet rich plasma (PRP) treatment in supraspinatus and common extensor of the forearm tendinosis by using texture analysis of ultrasound (US) images as well as by clinical questionnaires.

Patients And Methods: Thirteen patients (7 male and 6 female, age 36-60 years, mean age 51.

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Background: Dissolved oxygen has known paramagnetic effects in magnetic resonance imaging (MRI). The aim of this study was to compare the effects of normobaric oxygenation (NBO) and hyperbaric oxygenation (HBO) on human brain MRI signal intensities.

Patients And Methods: Baseline brain MRI was performed in 17 healthy subjects (mean age 27.

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This study aims to determine whether and to what extent the structure and composition of thrombi can be assessed using NMR and CT measurements. Seven different thrombus models, namely, six RBC thrombi with hematocrit levels (HTs) of 0%, 20%, 40%, 60%, 80% and 100% and one platelet thrombus model, were analyzed using proton NMR at 100 MHz and 400 MHz, with measurements of and NMR relaxation times and measurements of the apparent diffusion coefficient (ADC). In addition, the thrombus models were CT-scanned in a dual-energy mode (80 kV and 140 kV) and in a single-energy mode (80 kV) to measure their CT numbers.

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The precise characterization of cerebral thrombi prior to an interventional procedure can ease the procedure and increase its success. This study investigates how well cerebral thrombi can be characterized by computed tomography (CT), magnetic resonance (MR) and histology, and how parameters obtained by these methods correlate with each other as well as with the interventional procedure and clinical parameters. Cerebral thrombi of 25 patients diagnosed by CT with acute ischemic stroke were acquired by mechanical thrombectomy and, subsequently, scanned by a high spatial-resolution 3D MRI including -weighted imaging, apparent diffusion coefficient (ADC), mapping and then finally analyzed by histology.

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Background: The study was designed to evaluate the influence of hyperbaric oxygenation therapy (HBOT) on the parotid gland in patients following radiotherapy for head and neck tumours.

Patients And Methods: HBOT response was monitored by 3T magnetic resonance imaging (MRI) using mapping and subsequent measurement of mean and variability as well as by salivary tests (salivary flow, buffer capacity, and pH). Eighteen patients previously treated with irradiation doses between 50 and 80 Gy as well as 18 healthy gender and age matched controls were enrolled.

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Background: All the patients with suspected stroke are directed to whole-brain CT scan. The purpose of this scan is to look for early features of ischemia and to rule out alternative diagnoses than stroke. In case of ischemic stroke, CT diagnostics (including CT angiography) is used mainly to locate the occlusion and its size, while the Hounsfield Units (HU) values of the thrombus causing the stroke are usually overlooked on CT scan or considered not important.

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Background Recent advances in MRI technology makes it increasingly more competitive to CT also in the field of interventions. Multi-parametric MRI offers a significant amount of data relevant for characterization of human cerebral thrombi. Patients and methods Cerebral thrombi of 17 patients diagnosed with acute stroke were acquired by mechanical thrombectomy.

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Among radiological methods, magnetic resonance imaging (MRI) excels in its ability to image soft tissue at great contrast and without the need of harmful radiation. This study tested whether in vivo MRI based on standard MRI sequences run on a standard clinical MRI system can be used to quantify dental pulp response to caries progression using the T2 mapping method. In the study, 74 teeth were scanned on a 3-T MRI system, and caries was assessed according to the International Caries Detection and Assessment System (ICDAS).

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Background Pleural effusion remains largely unexplored in patients with pulmonary embolism and concurrent pulmonary infarction. The aim of the study was to investigate the relationship between the size of pulmonary infarction and pleural effusion as well as the time course of pleural effusion in patients with pulmonary infarction. Patients and methods Data from 103 patients with pulmonary infarction was retrospectively analysed along with patient comorbidities, size of pulmonary infarction, presence and size of pleural effusion with the time between the onset of clinical symptoms of pulmonary infarction and CT study.

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Quantitative magnetization transfer magnetic resonance imaging (qMT-MRI) was employed to characterize dry-cured ham tissues differing in anatomical positions and processing protocols. Experimentally obtained MR images of dry-cured ham sections were analyzed by the well-established binary-spin-bath (BSB) model. The model enabled an efficient discrimination between a free-water proton pool and a restricted-macromolecular proton pool.

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Background: We report on a case of pancreatic arteriovenous malformation (PAVM) that obliterated shortly after diagnostic angiography (DSA). PAVM is a rare anomaly that presents with upper abdominal pain, signs of acute pancreatitis and massive gastrointestinal bleeding. The management of PAVM is rather complex, with complete treatment usually accomplished only by a total extirpation of the affected organ or at least its involved portion.

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A novel multiparametric magnetic resonance microscopy (MRM) approach was applied to the Slovenian Kraški pršut dry-cured ham samples in order to evaluate its potential for discrimination among biceps femoris and semimembranosus muscle from two hams, differing in processing (salting duration) and thus in water and salt content. The approach is based on apparent diffusion coefficient (ADC) mapping as well as on longitudinal (T1) and transversal (T2) nuclear magnetic resonance relaxation time mapping. Three-dimensional maps were acquired and analyzed by one dimensional (1D) ADC, T1, and T2 distributions as well as by paired two-dimensional ADC-T1, ADC-T2 and T1-T2 distributions.

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Background: We report a case of unsuccessful percutaneous mechanical thrombectomy in treatment of a high-risk pulmonary embolism (PE). Pulmonary thromboemboli are commonly expected as a homogenous mass, rich with red blood cell content, which respond well to percutaneous mechanical thrombectomy (PMT). Catheter-based approach or surgical embolectomy are two treatment options that are usually considered for treatment of high-risk PE when the thrombolytic therapy fails or it is contraindicated due to a patient's persisting hemodynamic compromise.

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Background: The structure of thrombi plays an important role in delaying reperfusion and re-occlusion after intravenous thrombolysis and could influence the performance of mechanical thrombectomy devices. This study aims to distinguish various thrombi groups based on their T2 and apparent diffusion coefficient (ADC) properties.

Methods: 26 venous thrombi (VT), 28 acute (aPTE) and 18 chronic pulmonary thromboemboli (cPTE) and 18 sedimented clots (SC) were scanned by a three-dimensional T1 -weighted spin-echo sequence and by T2 and ADC mapping.

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Background: Altered neurovascular coupling in migraineurs could be a consequence of impaired function of modulatory brainstem nuclei. The cold pressor test (CPT) should activate brainstem structures. We measured visually evoked cerebral blood flow velocity response (VEFR) to CPT in migraine.

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The aim of this study was to evaluate an advanced magnetic resonance imaging (MRI) method, apparent diffusion coefficient (ADC) mapping, in the functional assessment of carious teeth. 38 extracted human teeth with scores of 0, 3 and 6 according to International Caries Detection and Assessment System (ICDAS) criteria were screened and subsequently analyzed by MRI at 2.35 T.

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Introduction: Plasmin is a direct-acting thrombolytic agent with a favorable safety profile upon intra-arterial delivery in pre-clinical and phase I studies. However, the thrombolytic efficacy of plasmin, relative to that of rt-PA, remains to be established. We have compared the dynamics of clot lysis with plasmin or rt-PA in an in vitro perfusion system, in which thrombolytic agent is administered locally, allowed to induce lysis for short intervals, then washed with plasma in a re-circulation circuit.

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Plasmin, a directly acting thrombolytic agent, demonstrated a very favorable safety profile upon intra-arterial delivery to the clot site; however, its thrombolytic efficacy remains to be further assessed. In this study, differences in thrombolysis between clots exposed to equimolar concentrations of plasmin and recombinant tissue-type plasminogen activator (rt-PA) after partial vessel recanalization were tested in a model system. Model blood clots were prepared in glass chambers enabling direct observation by dynamic optical microscopy.

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Thrombolytic therapy aims to dissolve blood clots and restore vessel patency. Our hypothesis is that the therapy depends not only on chemical reactions of the fibrinolytic system, but also on mechanical forces exerted by streaming blood on the clot surface. The aim of the study was to analyze the role of mechanical forces in promoting thrombolysis and their relation to the maximum size of removed clot fragments.

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The prognostic potential of apparent diffusion coefficient (ADC) mapping was studied as complemented by high-resolution 3D T(1)-weighted MRI in the assessment of dentin-pulp complex response to caries. Twenty-six extracted human teeth, with or without caries lesions of different grades in accord with the International Caries Detection and Assessment System (ICDAS), were analyzed by high-resolution MRI at 2.35 T.

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Purpose: To test whether T(1)-weighted MRI can detect the differences in the rate of thrombolysis induced by recombinant tissue plasminogen activator (rt-PA) between platelet-rich regions and red blood cell (RBC)-rich regions of venous thrombi ex vivo.

Materials And Methods: Each of 21 venous thrombi ex vivo (8 pulmonary emboli and 13 in situ thrombi) was dissected along the longitudinal axis. Half of it was analyzed for the presence of platelet, fibrin, and RBC components by immunohistochemistry and the other half was imaged serially by high-resolution T(1)-weighted three-dimensional MRI to assess the progression of thrombolysis.

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Although it is generally believed that the structure of venous thromboemboli is a homogeneous red blood cell-fibrin clot, their structure may be heterogeneous, with non-uniformly distributed platelet layers, known as the lines of Zahn. We tested (a) whether venous thromboemboli ex vivo contained platelet layers, i.e.

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Background: The aim of this study was to examine whether (31)P NMR can efficiently detect X-ray radiation induced changes of energy metabolism in mice. Exposure to ionizing radiation causes changes in energy supply that are associated with the tissue damage because of oxidative stress and uncoupled oxidative phosphorylation. This has as a consequence decreased phosphocreatine to adenosine triphosphate ratio (Pcr/ATP) as well as increased creatine kinase (CK) and liver enzymes (transaminases AST and ALT) levels in serum.

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Introduction: Although fibrinolytic treatment has been used for decades, the interactions between the biochemical mechanisms and the mechanical forces of the streaming blood remain incompletely understood. Analysis of the blood clot surface in vitro was employed to study the concomitant effect of blood plasma flow and recombinant tissue plasminogen activator (rt-PA) on the degradation of retracted, non-occlusive blood clots. Our hypothesis was that a faster tangential plasma flow removed larger fragments and resulted in faster overall thrombolysis.

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