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OBJECTIVES: The aim of our study was to assess the correlation between T2 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. Pulps of extracted teeth were histologically analysed. RESULTS: MRI T2 relaxation times (ms) were 111,9 ± 11.2 for ICDAS 0, 132.3 ± 18.5* for ICDAS 1, 124.6 ± 14.8 for ICDAS 2 and 112. 6 ± 18.2 for ICDAS 3 group (p = 0,013). A positive correlation was observed between MRI T2 relaxation times and macrophage and T lymphocyte density in healthy teeth. There was a positive correlation between vascular density and T2 relaxation times of dental pulp in teeth with ICDAS score 1. A negative correlation was found between T2 relaxation times and macrophage density. There was a positive correlation between T2 relaxation time variability and macrophage and T lymphocyte density in teeth with ICDAS score 2. In teeth with ICDAS score 3, a positive correlation between T2 relaxation times and T2 relaxation time variability and lymphocyte B density was found. CONCLUSION: The results of our study confirm the applicability of MRI in evaluation of the true condition of the pulp tissue. CLINICAL RELEVANCE: With the high correlation to histological validation, MRI method serves as a promising imaging implement in the field of general dentistry and endodontics.
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Cárie Dentária , Polpa Dentária , Humanos , Polpa Dentária/diagnóstico por imagem , Polpa Dentária/patologia , Sensibilidade e Especificidade , Cárie Dentária/patologia , Imageamento por Ressonância Magnética , Dente Pré-Molar/diagnóstico por imagem , Dente Pré-Molar/patologia , Reprodutibilidade dos TestesRESUMO
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). The T2 maps were processed to obtain T2 profiles along selected root canals (from crown to apex), and the profiles were sorted according to both tooth type (single-rooted vs. molar) and ICDAS score. In all the examined dental pulps, it was found that T2 values decrease with an increase in the ICDAS score. In the coronal part of dental pulps, average T2 values of 166, 153, and 115 ms were found in ICDAS groups 0, 1-3, and 4-6, respectively. In single-rooted teeth, T2 values were found approximately constant as a function of dental pulp depth, while in multi-rooted teeth, they were found increasing in the coronal part and decreasing towards the root apex. The study confirmed that T2 mapping of dental pulp can be used to reliably quantify its response to caries progression and that it has a potential to become a complementary diagnostic tool to standard radiographic methods in the assessment of dental pulp response to caries.
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Cárie Dentária , Dente , Cárie Dentária/diagnóstico por imagem , Polpa Dentária/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Dente Molar/diagnóstico por imagemRESUMO
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. DSA prior to treatment decisions is helpful for characterizing symptomatic PAVM, since it can clearly depict the related vascular networks. In addition, interventional therapy can be performed immediately after diagnosis. CASE PRESENTATION: A 39-old male was admitted due to recurring upper abdominal pain that lasted several weeks. Initial examination revealed the absence of fever or jaundice, and the laboratory tests, including that for pancreatic enzymes, were unremarkable. An abdominal ultrasound (US) showed morphological and Doppler anomalies in the pancreas that were consistent with a vascular formation. A subsequent DSA depicted a medium-sized nidus, receiving blood supply from multiple origins but with no dominant artery. Coil embolization was not possible due to the small caliber of the feeding vessels. In addition, sclerotherapy was not performed so as to avoid an unnecessary wash out to the non-targeted duodenum. Consequently, the patient received no specific treatment for his symptomatic PAVM. A large increase in pancreatic enzymes was noticed shortly after the DSA procedure. Imaging follow-up by means of CT and MRI showed small amounts of peripancreatic fluid along with a limited area of intra-parenchymal necrosis, indicating necrotizing pancreatitis. In the post-angiography follow-up the patient was hemodynamically stable the entire time and was treated conservatively. The symptoms of pancreatitis improved over a few days, and the laboratory findings returned to normal ranges. Long-term follow-up by way of a contrast-enhanced CT revealed no recanalization of the thrombosed PAVM. CONCLUSION: The factors associated with the obliteration of PAVM during or after DSA are poorly understood. In our case it may be attributed to the low flow dynamics of PAVM, as well as to the local administration of a contrast agent. Asymptomatic PAVM, as diagnosed with non-invasive imaging techniques, should not be evaluated with DSA due to the potential risk of severe complications, such as acute pancreatitis.
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Angiografia/efeitos adversos , Malformações Arteriovenosas/complicações , Malformações Arteriovenosas/diagnóstico por imagem , Pâncreas/irrigação sanguínea , Trombose/etiologia , Dor Abdominal/etiologia , Adulto , Humanos , Masculino , Pancreatite/etiologiaRESUMO
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. Immunohistochemical analysis was used as a reference. Differences in the ADC, T2 and paired ADC-T2 distributions between the various thrombi group pairs were analyzed by standard statistics as well as by overlap integrals. RESULTS: Paired ADC-T2 distribution enabled the most efficient discrimination of structural changes between pairs of thrombi. For thrombi pairs VT-cPTE, VT-SC, aPTE-cPTE, aPTE-SC, cPTE-SC differences were statistically significant (pADC , pT 2 , pADC-T 2 < 0.05) and the values of the overlap integrals were low (OIADC ≤ 0.505, OIT2 ≤ 0.823, OIADC-T2 ≤ 0.379). Least efficient was the structural discrimination for the VT-aPTE pair (pT 2 = 0.877, OIT2 = 0.940). CONCLUSION: Multiparametric MRI is an efficient method for discriminating different thrombi groups at various stages of organization.
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Imageamento Tridimensional/métodos , Angiografia por Ressonância Magnética/métodos , Imagem Multimodal/métodos , Embolia Pulmonar/patologia , Veias Pulmonares/patologia , Trombose Venosa/patologia , Diagnóstico Diferencial , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Técnicas In Vitro , Modelos Biológicos , Modelos Estatísticos , Artéria Pulmonar/patologia , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
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. METHODS: Twenty-three healthy volunteers and 29 migraineurs participated in the study. We measured arterial blood pressure, end-tidal CO2, heart rate and cerebral blood flow velocity in posterior and middle cerebral artery using transcranial Doppler. VEFR was calculated as cerebrovascular reactivity to photic stimulation before, during and after CPT. RESULTS: In healthy individuals, there was a significant decrease in peak systolic VEFR from CPT phase to recovery phase (p < 0.05). There was an increase in mean VEFR from basal to CPT phase and a decrease from CPT to recovery phase, both significant (p < 0.05). End-diastolic VEFR increased from basal to CPT phase and decreased in recovery phase below the basal phase values, all changes significant (p < 0.05). In migraine, no statistically significant changes in peak systolic, mean or end-diastolic VEFRs were observed between phases (p > 0.05). The differences in phases in mean and end-diastolic VEFRs between the basal phase and the CPT phase and between the CPT phase and the recovery phase were significantly higher in healthy individuals (p < 0.05). CONCLUSIONS: The absence of the effect of CPT on VEFR in migraine is likely to be a consequence of impaired subcortical modulation of neurovascular coupling.
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Encéfalo/irrigação sanguínea , Circulação Cerebrovascular/fisiologia , Transtornos de Enxaqueca/fisiopatologia , Acoplamento Neurovascular/fisiologia , Adulto , Potenciais Evocados Visuais/fisiologia , Feminino , Humanos , Masculino , Ultrassonografia Doppler TranscranianaRESUMO
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. Currently, selection criteria for PE treatment options are based mostly on the assessment of patient's history. The aim of this report is to highlight a possible treatment complication in PMT of structurally heterogeneous thrombotic mass due to PMT inadequacy. CASE PRESENTATION: A 32 year-old male with polytrauma was admitted to an intensive care unit after a right-sided nephrectomy and evacuation of retroperitoneal hematoma. The patient initial haemostatic disorder was improved by administration of blood preparations, an anti-fibrinolytic agent and concentrates of fibrinogen. On the third day he presented sudden onset of hemodynamic instability and was incapable of standard CTA diagnostic procedure. Urgent and relevant investigations including transthoracic and transesophageal echocardiogram confirmed a high-risk PE. PMT was performed due to contraindications for systemic thrombolysis. Long-term PMT was attempted using aspiration with several devices. No major improvement was achieved in any of the treatments and the patient died. Autopsy confirmed a large heterogeneous thrombotic mass in the pulmonary trunk folding to the right main artery. Additional histological analysis revealed a high fibrin-rich content in the peripheral surroundings of the thrombus. CONCLUSION: In the case, it was confirmed that the outcome of PMT was directly influenced by mechanical and histological features of the thromboembolus in high-risk PE. Formation of a rather complex thromboembolus in high-risk PE favors surgical embolectomy as the only life-saving treatment option. Current diagnostic imaging techniques do not enable precise assessment of thrombi structure and are therefore unable to identify patients who might benefit from PMT or open surgical embolectomy. Surgical backup treatment should be considered if there are no contraindications in the event of a failed catheter intervention.
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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. Histology sectioning of teeth was used for the gold standard by analyzing two extreme cases (intact and severely decayed). ADC maps of the same teeth were calculated from corresponding diffusion-weighted images and used to obtain ADC distributions along dental pulp as functions of the relative pulp length measured from the occlusal pulp side. The measured distributions were analyzed for the best fit by a four-parameter three-segment linear regression model for ADC distribution along the pulp. MRI results were in good agreement with findings in histological sections of identical teeth. The best fit model parameters, relative decayed region depth, relative transition region width and ADC values of intact and decayed pulp tissue, showed statistically significant differences between the ADC values of intact and decayed pulp tissue (1.0 × 10(-9) m(2)/s vs. 0.74-0.89 × 10(-9) m(2)/s) and the relative decayed region depth progressing with ICDAS score (3 vs. 46% with ICDAS 3 vs. ICDAS 6). The results of this feasibility study confirmed relevance of ADC mapping for the discrimination and localization of intact and decayed regions in dental pulps of carious teeth.
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Cárie Dentária/diagnóstico , Polpa Dentária/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Aumento da Imagem/métodos , Adulto , Dente Pré-Molar/patologia , Cárie Dentária/patologia , Esmalte Dentário/patologia , Dentina/patologia , Progressão da Doença , Estudos de Viabilidade , Humanos , Modelos Lineares , Modelos Biológicos , Dente Molar/patologia , Pulpite/diagnóstico , Pulpite/patologia , Desmineralização do Dente/diagnóstico , Desmineralização do Dente/patologia , Adulto JovemRESUMO
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 27.8 ± 3.2). MRI was repeated after exposure to the NBO and HBO at different time points (0 min, 25 min, 50 min). Signal intensities in T 1-weighted, T 2-weighted images and fluid attenuated inversion recovery (FLAIR) signal intensities of several intracranial structures were compared between NBO and HBO. RESULTS: Increased T 1-weighted signal intensities were observed in white and deep grey brain matter, cerebrospinal fluid (CSF), venous blood and vitreous body after exposure to NBO as well as to HBO compared to baseline (Dunnett's test, p < 0.05) without significant differences between both protocols. There was also no significant difference in T 2-weighted signal intensities between NBO and HBO. FLAIR signal intensities were increased only in the vitreous body after NBO and HBO and FLAIR signal of caudate nucleus was decreased after NBO (Dunnett's test, p < 0.05). The statistically significant differences in FLAIR signal intensities were found between NBO and HBO (paired t-test, p < 0.05) in most observed brain structures (paired t-test, p < 0.05). CONCLUSIONS: Our results show that NBO and HBO alters signal intensities T 1-weighted and FLAIR images of human brain. The differences between NBO and HBO are most pronounced in FLAIR imaging.
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Oxigenoterapia Hiperbárica , Humanos , Adulto Jovem , Adulto , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética , Voluntários SaudáveisRESUMO
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 T1 and T2 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. The results confirmed that RBC thrombi can be distinguished from platelet thrombi by using ADC and CT number measurements in all three settings, while they cannot be distinguished by using T1 and T2 measurements. All measured parameters allowed for the differentiation of RBC thrombi according to their HT values, but the best sensitivity to HT was obtained with ADC and single-energy CT measurements. The importance of this study also lies in the potential application of its results for the characterization of actual thrombi in vivo.
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BACKGROUND: Computer-aided diagnosis (i.e., 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 51.2 ± 5.2) were followed after US guided PRP treatment for tendinosis of two tendons (9 patients with lateral epicondylitis and 4 with supraspinatus tendinosis). Clinical and US assessment was performed prior to as well as 3 months after PRP treatment with validated clinical questionnaires. Tissue response in tendons was assessed by using gray level run length matrix method (GLRLM) of US images. RESULTS: All patients improved of tendinosis symptoms after PRP treatment according to clinical questionnaires. Almost all GLRLM features were statistically improved 3 months after PRP treatment. GLRLM-long run high gray level emphasis (LRLGLE) revealed the best moderate positive and statistically significant correlation after PRP (r = 0.4373, p = 0.0255), followed by GLRLM-low gray level run emphasis (LGLRE) (r = 0.3877, p = 0.05). CONCLUSIONS: Texture analysis of tendinosis US images was a useful quantitative method for the assessment of tendon remodeling after minimally invasive PRP treatment. GLRLM features have the potential to become useful imaging biomarkers to monitor spatial and time limited tissue response after PRP, however larger studies with similar protocols are needed.
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Plasma Rico em Plaquetas , Tendinopatia , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Resultado do Tratamento , Projetos Piloto , Ultrassonografia , Plasma Rico em Plaquetas/diagnóstico por imagem , Tendinopatia/diagnóstico por imagem , Tendinopatia/terapiaRESUMO
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. A signal rise in demineralized hard dental tissues in high-resolution T(1)-weighted MR images enabled assessment of the demineralization depth over the whole range of ICDAS scores. ADC maps of the teeth were calculated from corresponding diffusion-weighted images of four different b values: 0, 132, 317, 635 s/mm(2). These maps enabled reliable differentiation between intact (ADC > 1.0·10(-9) m(2)/s) and affected (ADC < 1.0·10(-9) m(2)/s) regions of dental pulp. Linear regression analyses of demineralization depth in relation to ICDAS score and then also to average ADC of dental pulp showed that a demineralization depth increase of one millimeter corresponds to an ICDAS score increase of 1.2 and an average ADC decrease of 0.07·10(-9) m(2)/s. Results of the study indicate that the average ADC value of dental pulp could be used as a potential marker to assess tissue response to caries comparable to that of ICDAS scoring.
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Cárie Dentária/patologia , Polpa Dentária/patologia , Dentina/patologia , Imageamento por Ressonância Magnética/métodos , Difusão , Humanos , Imageamento Tridimensional , Processamento de Sinais Assistido por Computador , Desmineralização do DenteRESUMO
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. Non-occlusive whole-blood clots were exposed to flow of plasma containing the thrombolytic agent rt-PA. Plasma, perfusing through the clot, was collected and the sizes of clot degradation fragments in the plasma were analyzed by optical microscopy. Theoretical models for the maximum clot fragment size as a function of blood flow velocity were developed based on the relation between surface or volume clot binding forces and the opposing forces of the streaming plasma in the laminar or turbulent flow regime. The best agreement between experimental results and models was obtained for the volume binding forces and the laminar flow model, in which the maximum clot fragment size was linearly dependent on the plasma flow velocity. Such result could not be obtained if thrombolysis would be purely a biochemical process. Therefore, the result confirms our hypothesis that thrombolysis is also strongly influenced by the mechanical forces of streaming plasma.
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Coagulação Sanguínea/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Trombólise Mecânica/métodos , Modelos Cardiovasculares , Trombose/fisiopatologia , Animais , Viscosidade Sanguínea/fisiologia , Simulação por Computador , HumanosRESUMO
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 T2 mapping and subsequent measurement of mean T2 and T2 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. MRI was performed prior to HBOT (40.2 ± 20 months after radiotherapy) and after 20 daily HBOT at 2.5 ATA (absolute atmosphere). Each HBOT consisted of breathing 100% oxygen for 90 minutes. RESULTS: Significant differences in mean T2 prior to HBOT were observed between the ipsilateral irradiated (121 ± 20 ms), contralateral parotids (107 ± 21) and control group (96 ± 12 ms). A positive correlation in patients between T2 variability and irradiation dose was detected in contralateral parotids before HBOT (R = 0.489, p = 0.0287). In addition, negative correlations were observed between mean T2 in the ipsilateral as well as the contralateral gland and salivary flow before and after HBOT. Negative correlations between mean T2, T2 variability and pH of unstimulated saliva were also observed in the sides of parotid before and after HBOT. CONCLUSIONS: The study confirmed that T2 mapping had a potential for monitoring the differences between irradiated and normal parotid glands. It could also be useful in the assessment of the glandular tissue response to HBOT.
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Neoplasias de Cabeça e Pescoço , Oxigenoterapia Hiperbárica , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Oxigenoterapia Hiperbárica/efeitos adversos , Oxigenoterapia Hiperbárica/métodos , Glândula Parótida/diagnóstico por imagem , SalivaRESUMO
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 T1-weighted imaging, apparent diffusion coefficient (ADC), T2 mapping and then finally analyzed by histology. Parameter pairs with Pearson correlation coefficient more than 0.5 were further considered by explaining a possible cause for the correlation and its impact on the difficulty of the interventional procedure and the treatment outcome. Significant correlations were found between the variability of ADC and the duration of the mechanical recanalization, the deviation in average Hounsfield units (HU) and the number of passes with the thrombectomy device, length of the thrombus, its RBC content and many others. This study also demonstrates the clinical potentials of high spatial resolution multiparametric MRI in characterization of thrombi and its use for interventional procedure planning.
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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. The MR images were analyzed for proportions of the remaining platelet-rich and RBC-rich regions. RESULTS: Laminated platelet-rich regions, corresponding to Zahn lines, were confirmed immunohistochemically and by MRI in 18/21 venous thrombi. In T(1)-weighted MR images (TE/TR = 10/105 ms) the mean signal intensity of platelet-rich regions was on average 2.3 higher than that of RBC-rich regions. The rate of thrombolysis in platelet-rich regions was on average 30% lower than in RBC-rich regions. After 120 min of thrombolysis the proportion of lysed platelet-rich regions was 0.27 ± 0.04 versus 0.40 ± 0.08 in RBC regions, which resulted in 1.4% decrease of lysed thrombus volume per 1% increase of platelet-rich content. CONCLUSION: Venous thrombi are most often composed of interspersed platelet-rich and RBC-rich regions. T(1) -weighted MRI is capable of noninvasive discrimination between those two components of venous thrombi ex vivo which have a different susceptibility to thrombolysis by rt-PA.
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Plaquetas/citologia , Eritrócitos/patologia , Imageamento por Ressonância Magnética/métodos , Terapia Trombolítica/métodos , Trombose Venosa/terapia , Plaquetas/metabolismo , Eritrócitos/metabolismo , Fibrina/metabolismo , Humanos , Imuno-Histoquímica/métodos , Estudos Longitudinais , Ativadores de Plasminogênio/metabolismo , Proteínas Recombinantes/metabolismo , Trombose/patologia , Trombose Venosa/patologiaRESUMO
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. The aim of this study was to demonstrate that the HU value is relevant and can help in better treatment planning. PATIENTS AND METHODS: There were 25 patients included in the study, diagnosed with ischemic stroke in the middle cerebral artery (MCA) territory. In all patients, systemic thrombolysis was not successful and the mechanical recanalization was needed. The retrieved thrombi were also analyzed histologically for the determination of red blood cells (RBC) proportion. CT of the proximal MCA (M1) segment was analyzed for average HU value and its variability both in the occluded section and the symmetrical normal site. These CT parameters were then statistically studied for the possible correlations with different clinical, histological and procedure parameters using the Linear Regression and the Pearson correlation coefficient. RESULTS: Relevant positive correlations were found between average HU value of thrombus and outcome modified Rankin Scale (mRS), initial mRS, number of passes with thrombectomy device as well as RBC proportion. CONCLUSIONS: Results of the present study suggest that measured HU values in CT images of the cerebral thrombi may help in the assessment of thrombus compaction and therefore better treatment planning.
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Trombose Intracraniana , AVC Isquêmico , Humanos , Trombose Intracraniana/diagnóstico por imagem , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/terapia , Trombose/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Resultado do TratamentoRESUMO
The structural characteristics of blood clots are associated with their susceptibility to thrombolysis. As their morphology can be characterized by MRI, several attempts have been made to link the lysability of blood clots with their MRI properties; however, so far no study has associated a clot's lysability with the diffusion properties of the water in the clot. The apparent diffusion coefficient (ADC) is highly sensitive to changes in serum mobility and may be used to distinguish between the non-retracted and the fully retracted regions of the blood clot. Therefore, the ADC may be a suitable, or even a better, marker for an assessment of the clot's retraction and consequently for its lysability than the relaxation time T(2). The purpose of this study was to evaluate whether it is possible to predict the outcome of clot thrombolysis by ADC mapping prior to treatment. After two hours of thrombolysis using a recombinant tissue plasminogen activator in plasma, whole-blood clots were efficiently dissolved in regions with ADC >or= 0.8 x 10(-9) m(2)/s or T(2) >or= 130 ms, whereas dissolution was poor and prolonged in regions with ADC < 0.8 x 10(-9) m(2)/s or T(2) < 130 ms. An analysis based on a comparison between the initial and final ADC and T(2) maps after two hours of thrombolysis showed that the ADC can more accurately detect the different grades of clot retraction than T(2) and predict the regions of a clot that are resistant to thrombolysis. Therefore, the ADC could be used as an efficient prognostic marker for the outcome of thrombolysis. However, in vivo studies are needed to test this idea.
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Imageamento por Ressonância Magnética/métodos , Terapia Trombolítica/métodos , Trombose , Fibrina/metabolismo , Humanos , Trombose/metabolismo , Trombose/patologia , Ativador de Plasminogênio Tecidual/metabolismo , Resultado do TratamentoRESUMO
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. The thrombi were subsequently scanned using a high spatial-resolution 3D T1-weighted MRI to obtain morphological characteristics of the thrombi and also by apparent diffusion coefficient (ADC) and transversal nuclear magnetic resonance (NMR) relaxation time (T2) mapping. The MRI results were analysed for possible correlations between thrombectomy procedure parameters (recanalization time and number of passes) and MR-measurable parameters (sample-mean ADC and T2, within-sample coefficient of variation of ADC and T2, and thrombus length). Results Both MRI mapping techniques enabled a good discrimination among thrombi regions of different water mobility and compaction. Within-sample coefficient of variation of ADC was found most sensitive for discrimination between the thrombi where thrombectomy procedure was performed in a single pass and those where is was performed in two or more passes (p = 0.03). Interestingly, negative correlation was found between the recanalization time and thrombus length (ρ = -0.22). Conclusions Preliminary results of presented study shows that pretreatment MRI assessment of thrombi in stroke patients could potentially ease stroke treatment planning. In this study it is shown that within-sample coefficient of variation of ADC could serve for prediction of possible complications during thrombectomy procedures.
Assuntos
Isquemia Encefálica/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Imagem de Difusão por Ressonância Magnética , Processamento de Imagem Assistida por Computador , Trombose Intracraniana/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/patologia , Feminino , Humanos , Aumento da Imagem , Trombose Intracraniana/patologia , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Acidente Vascular Cerebral/patologia , TrombectomiaRESUMO
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. Results Assessment of possible correlations between the size of pulmonary infarction and age revealed a significant negative correlation. There was a highly significant difference (p = 0.005) in the mean size of pulmonary infarction in patients with effusion (34.5 cm3) compared to those without it (14.3 cm3), but the size of the effusion had no correlation with the size of pulmonary infarction. The size of the effusion peaked between 4th-5th day after the onset of clinical symptoms of pulmonary infarction. In the first 5 days after the onset of clinical symptoms of pulmonary infarction a significant correlation was found between the size of the effusion and time with approximation of 1.3 mm/12 h. Conclusions The data shows that patients with a pleural effusion are more likely to have a larger pulmonary infarction than those without it. If present, the effusion can be expected to increase in a relatively slow linear fashion in the first 5 days after the onset of clinical symptoms of pulmonary infarction.
Assuntos
Angiografia por Tomografia Computadorizada/métodos , Derrame Pleural/diagnóstico por imagem , Infarto Pulmonar/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Derrame Pleural/etiologia , Infarto Pulmonar/complicações , Estudos RetrospectivosRESUMO
A novel multiparametric magnetic resonance microscopy (MRM) approach was applied to the Slovenian Kraski prsut 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. The discriminating potential of the applied MRM approach was confirmed by differences among both 1D and 2D distributions of different ham samples. In addition, distribution peak positions highly correlated with the conventionally determined moisture content.