Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 58
Filtrar
1.
Abdom Radiol (NY) ; 46(5): 1912-1921, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33156949

RESUMO

BACKGROUND: The aim of this proof-of-concept study was to show that the liver segmental volume and attenuation ratio (LSVAR) improves the detection of significant liver fibrosis on portal venous CT scans by adding the liver vein to cava attenuation (LVCA) to the liver segmental volume ratio (LSVR). MATERIAL AND METHODS: Patients who underwent portal venous phase abdominal CT scans and MR elastography (reference standard) within 3 months between 02/2016 and 05/2017 were included. The LSVAR was calculated on portal venous CT scans as LSVR*LVCA, while the LSVR represented the volume ratio between Couinaud segments I-III and IV-VIII, and the LVCA represented the density of the liver veins compared to the density in the vena cava. The LSVAR and LSVR were compared between patients with and without significantly elevated liver stiffness (based on a cutoff value of 3.5 kPa) using the Mann-Whitney U test and ROC curve analysis. RESULTS: The LSVR and LSVAR allowed significant differentiation between patients with (n = 19) and without (n = 122) significantly elevated liver stiffness (p < 0.001). However, the LSVAR showed a higher area under the curve (AUC = 0.96) than the LSVR (AUC = 0.74). The optimal cutoff value was 0.34 for the LSVR, which detected clinically increased liver stiffness with a sensitivity of 53% and a specificity of 88%. With a cutoff value of 0.67 for the LSVAR, the sensitivity increased to 95% while maintaining a specificity of 89%. CONCLUSION: The LSVAR improves the detection of significant liver fibrosis on portal venous CT scans compared to the LSVR.


Assuntos
Técnicas de Imagem por Elasticidade , Cirrose Hepática , Humanos , Fígado/diagnóstico por imagem , Fígado/patologia , Cirrose Hepática/diagnóstico por imagem , Cirrose Hepática/patologia , Veia Porta/diagnóstico por imagem , Tomografia Computadorizada por Raios X
2.
Proc Natl Acad Sci U S A ; 117(28): 16226-16233, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601231

RESUMO

Competing interactions in quantum materials induce exotic states of matter such as frustrated magnets, an extensive field of research from both the theoretical and experimental perspectives. Here, we show that competing energy scales present in the low-dimensional orbital-selective Mott phase (OSMP) induce an exotic magnetic order, never reported before. Earlier neutron-scattering experiments on iron-based 123 ladder materials, where OSMP is relevant, already confirmed our previous theoretical prediction of block magnetism (magnetic order of the form [Formula: see text]). Now we argue that another phase can be stabilized in multiorbital Hubbard models, the block-spiral state. In this state, the magnetic islands form a spiral propagating through the chain but with the blocks maintaining their identity, namely rigidly rotating. The block-spiral state is stabilized without any apparent frustration, the common avenue to generate spiral arrangements in multiferroics. By examining the behavior of the electronic degrees of freedom, parity-breaking quasiparticles are revealed. Finally, a simple phenomenological model that accurately captures the macroscopic spin spiral arrangement is also introduced, and fingerprints for the neutron-scattering experimental detection are provided.

3.
Phys Rev Lett ; 123(2): 027203, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31386537

RESUMO

Inelastic neutron scattering recently confirmed the theoretical prediction of a ↑↑↓↓-magnetic state along the legs of quasi-one-dimensional iron-based ladders in the orbital-selective Mott phase (OSMP). We show here that electron doping of the OSMP induces a whole class of novel block states with a variety of periodicities beyond the previously reported π/2 pattern. We discuss the magnetic phase diagram of the OSMP regime that could be tested by neutrons once appropriate quasi-1D quantum materials with the appropriate dopings are identified.

4.
Sci Rep ; 9(1): 8106, 2019 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147588

RESUMO

Magnetic resonance (MR) T1 and T2* mapping allows quantification of liver relaxation times for non-invasive characterization of diffuse liver disease. We hypothesized that liver relaxation times are not only influenced by liver fibrosis, inflammation and fat, but also by air in liver segments adjacent to the lung - especially in MR imaging at 3T. A total of 161 study participants were recruited, while 6 patients had to be excluded due to claustrophobia or technically uninterpretable MR elastography. Resulting study population consisted of 12 healthy volunteers and 143 patients who prospectively underwent multiparametric MR imaging at 3T. Of those 143 patients, 79 had normal liver stiffness in MR elastography (shear modulus <2.8 kPa, indicating absence of fibrosis) and normal proton density fat fraction (PDFF < 10%, indicating absence of steatosis), defined as reference population. T1 relaxation times in these patients were significantly shorter in liver segments adjacent to the lung than in those not adjacent to the lung (p < 0.001, mean of differences 33 ms). In liver segments not adjacent to the lung, T1 allowed to differentiate significantly between the reference population and patients with steatosis and/or fibrosis (p ≤ 0.011), while there was no significant difference of T1 between the reference population and healthy volunteers. In conclusion, we propose to measure T1 relaxation times in liver segments not adjacent to the lung. Otherwise, we recommend taking into account slightly shorter T1 values in liver segments adjacent to the lung.


Assuntos
Fígado Gorduroso/patologia , Hepatopatias/patologia , Fígado/patologia , Imageamento por Ressonância Magnética , Idoso , Fígado Gorduroso/diagnóstico por imagem , Fígado Gorduroso/metabolismo , Feminino , Humanos , Fígado/diagnóstico por imagem , Hepatopatias/diagnóstico por imagem , Hepatopatias/metabolismo , Pulmão/diagnóstico por imagem , Pulmão/metabolismo , Pulmão/patologia , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Prótons , Relaxamento/fisiologia , Fatores de Risco
5.
Artigo em Inglês | MEDLINE | ID: mdl-29542838

RESUMO

BACKGROUND: A large proportion of age-related fecal incontinence is attributed to weakness or degeneration of the muscles composing the anal continence organ. However, the individual role of these muscles and their functional interplay remain poorly understood. METHODS: This study employs a novel technique based on the combination of MR imaging and FLIP measurements (MR-FLIP) to obtain anatomical and mechanical information simultaneously. Unlike previous methods used to assess the mechanics of the continence organ, MR-FLIP allows inter-individual comparisons and statistical analysis of the sphincter morpho-mechanical parameters. The anatomy as well as voluntary and involuntary mechanical properties of the anal continence organ were characterized in 20 healthy senior volunteers. RESULTS: Results showed that the external anal sphincter (EAS) forms a funnel-like shape with wall thickness increasing by a factor of 2.5 from distal (6 ± 0 mm) to proximal (15 ± 3 mm). Both voluntary and involuntary mechanical properties in this region correlate strongly with the thickness of the muscle. The positions of least compliance and maximal orifice closing were both located toward the proximal EAS end. In addition, maximal contraction during squeeze maneuvers was reached after 2 s, but high muscle fatigue was measured during a 7 s holding phase, corresponding to about 60% loss of the energy produced by the muscles during the contraction phase. CONCLUSIONS: This work reports baseline parameters describing the morpho-mechanical condition of the sphincter muscle of healthy elderly volunteers. New parameters were also proposed to quantify the active properties of the muscles based on the mechanical energy associated with muscle contraction and fatigue. This information could be used to assess patients suffering from AI or for the design of novel implants.

6.
Colorectal Dis ; 19(8): 764-771, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27997766

RESUMO

AIM: Continence results from a complex interplay between anal canal (AC) muscles and sensorimotor feedback mechanisms. The passive ability of the AC to withstand opening pressure - its compliance - has recently been shown to correlate with continence. A functional lumen imaging probe (FLIP) is used to assess AC compliance, although it provides no anatomical information. Therefore, assessment of the compliance specific anatomical structures has not been possible, and the anatomical position of critical functional zones remains unknown. In addition, the FLIP technique assumes a circular orifice cross-section, which has not been shown for the AC. To address these shortcomings, a technique combining FLIP with a medical imaging modality is needed. METHOD: We implemented a new research method (MR-FLIP) that combines FLIP with MR imaging. Twenty healthy volunteers underwent MR-FLIP and conventional FLIP assessment. MR-FLIP was validated by comparison with FLIP results. Anatomical markers were identified, and the cross-sectional shape of the orifice was investigated. RESULTS: MR-FLIP provides compliance measurements identical to those obtained by conventional FLIP. Anatomical analysis revealed that the least compliant AC zone was located at the proximal end of the external anal sphincter (EAS). The cross-sectional shape of the AC was found to deviate only slightly from circularity in healthy volunteers. CONCLUSION: The proposed method is equivalent to classical FLIP. It establishes for the first time direct mapping between local tissue compliance and anatomical structure, which is key to gaining novel insights into (in)continence. In addition, MR-FLIP provides a tool for better understanding conventional FLIP measurements in the AC by quantifying its limitations and assumptions.


Assuntos
Canal Anal/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Manometria/métodos , Músculo Liso/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Canal Anal/anatomia & histologia , Canal Anal/fisiologia , Fenômenos Biomecânicos , Estudos Transversais , Incontinência Fecal/diagnóstico por imagem , Incontinência Fecal/fisiopatologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Liso/anatomia & histologia , Músculo Liso/fisiologia , Pressão , Estudos Prospectivos
7.
Eur J Radiol Open ; 3: 74-78, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27957517

RESUMO

PURPOSE: Crohn's disease is a type of inflammatory bowel disease affecting estimated 4 million people worldwide. Therapy stratification of Crohn's disease (CD) is mainly based on the inflammatory activity being assessed by endoscopic biopsy and clinical criteria. Cross-sectional imaging allows for the assessment of structural characteristics of the entire gastrointestinal tract including small bowel loops and may provide potential non-invasive image-based biomarkers for the inflammatory activity of CD. The aim of this study was to explore the predictive value of Computed Tomography-based morphologic patterns for inflammatory activity in CD. MATERIAL AND METHODS: 42 patients diagnosed with CD were included in a retrospective study (13 male, 29 female, median age 32 years). Abdominal CT imaging was carried out on symptomatic patients at a single institution 0-10 days prior to endoscopic biopsy or surgery using a protocol optimized for the characterization of structural bowel alterations. Image data were initially reviewed independently by three radiologists and discrepancies were settled in consensus with a focus on mesenteric fat stranding and combing, mesenteric adenopathy, mesenteric abscess, intraperitoneal free fluid, fistula, skip lesions, highest wall thickness and the localization of the affected bowel. The extent of inflammatory activity in the bowel wall was determined subsequently by histological analysis. RESULTS: All intestinal and extraintestinal CT findings except the mesenteric comb sign showed a tendency towards higher extent or prevalence in patients with high histological inflammatory activity score, especially median bowel wall thickness (6.0 mm vs. 3.5 mm), mesenteric abscesses (32% vs. 0%) and mesenteric adenopathy (94% vs. 45%). Spearman rank order correlation coefficient indicated a significant correlation of bowel wall thickness (r = 0.40, p < 0.05), mesenteric adenopathy (r = 0.54, p < 0.05), mesenteric abscess (r = 0.33, p < 0.05) and mesenteric fat stranding (r = 0.33, p < 0.05) with the histological inflammatory activity score. CONCLUSION: CT-based biomarkers including wall thickness, mesenteric fat stranding, mesenteric lymphadenopathy and mesenteric abscess positively correlated with the histological inflammatory activity score and therefore provided additional information for therapy stratification in symptomatic patients with CD, particularly as most of these biomarkers are hidden from endoscopy.

9.
Rofo ; 188(2): 163-71, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26529263

RESUMO

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of full-body linear X-ray scanning (LS) in multiple trauma patients in comparison to 128-multislice computed tomography (MSCT). MATERIALS AND METHODS: 106 multiple trauma patients (female: 33; male: 73) were retrospectively included in this study. All patients underwent LS of the whole body, including extremities, and MSCT covering the neck, thorax, abdomen, and pelvis. The diagnostic accuracy of LS for the detection of fractures of the truncal skeleton and pneumothoraces was evaluated in comparison to MSCT by two observers in consensus. Extremity fractures detected by LS were documented. RESULTS: The overall sensitivity of LS was 49.2 %, the specificity was 93.3 %, the positive predictive value was 91 %, and the negative predictive value was 57.5 %. The overall sensitivity for vertebral fractures was 16.7 %, and the specificity was 100 %. The sensitivity was 48.7 % and the specificity 98.2 % for all other fractures. Pneumothoraces were detected in 12 patients by CT, but not by LS. 40 extremity fractures were detected by LS, of which 4 fractures were dislocated, and 2 were fully covered by MSCT. CONCLUSION: The diagnostic accuracy of LS is limited in the evaluation of acute trauma of the truncal skeleton. LS allows fast whole-body X-ray imaging, and may be valuable for detecting extremity fractures in trauma patients in addition to MSCT. KEY POINTS:  The overall sensitivity of LS for truncal skeleton injuries in multiple-trauma patients was < 50 %. The diagnostic reference standard MSCT is the preferred and reliable imaging modality. LS may be valuable for quick detection of extremity fractures.


Assuntos
Tomografia Computadorizada Multidetectores/métodos , Traumatismo Múltiplo/diagnóstico por imagem , Imagem Corporal Total/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Sensibilidade e Especificidade , Adulto Jovem
10.
Mol Psychiatry ; 21(9): 1309-20, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26643538

RESUMO

It is still controversial which mediators regulate energy provision to activated neural cells, as insulin does in peripheral tissues. Interleukin-1ß (IL-1ß) may mediate this effect as it can affect glucoregulation, it is overexpressed in the 'healthy' brain during increased neuronal activity, and it supports high-energy demanding processes such as long-term potentiation, memory and learning. Furthermore, the absence of sustained neuroendocrine and behavioral counterregulation suggests that brain glucose-sensing neurons do not perceive IL-1ß-induced hypoglycemia. Here, we show that IL-1ß adjusts glucoregulation by inducing its own production in the brain, and that IL-1ß-induced hypoglycemia is myeloid differentiation primary response 88 protein (MyD88)-dependent and only partially counteracted by Kir6.2-mediated sensing signaling. Furthermore, we found that, opposite to insulin, IL-1ß stimulates brain metabolism. This effect is absent in MyD88-deficient mice, which have neurobehavioral alterations associated to disorders in glucose homeostasis, as during several psychiatric diseases. IL-1ß effects on brain metabolism are most likely maintained by IL-1ß auto-induction and may reflect a compensatory increase in fuel supply to neural cells. We explore this possibility by directly blocking IL-1 receptors in neural cells. The results showed that, in an activity-dependent and paracrine/autocrine manner, endogenous IL-1 produced by neurons and astrocytes facilitates glucose uptake by these cells. This effect is exacerbated following glutamatergic stimulation and can be passively transferred between cell types. We conclude that the capacity of IL-1ß to provide fuel to neural cells underlies its physiological effects on glucoregulation, synaptic plasticity, learning and memory. However, deregulation of IL-1ß production could contribute to the alterations in brain glucose metabolism that are detected in several neurologic and psychiatric diseases.


Assuntos
Interleucina-1beta/metabolismo , Neurônios/metabolismo , Animais , Astrócitos/imunologia , Astrócitos/metabolismo , Comunicação Autócrina/fisiologia , Encéfalo/imunologia , Encéfalo/metabolismo , Células Cultivadas , Glucose/metabolismo , Humanos , Interleucina-1beta/imunologia , Aprendizagem/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Camundongos , Fator 88 de Diferenciação Mieloide/metabolismo , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/imunologia , Comunicação Parácrina/fisiologia , Transdução de Sinais/efeitos dos fármacos
11.
Pneumologie ; 69(8): 469-76, 2015 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-26258421

RESUMO

INTRODUCTION: Inhaled drugs can only be effective if they reach the middle and small airways. This study introduces a system that combines a trans-nasal application of aerosols with noninvasive pressure support ventilation. METHODS: In a pilot study, 7 COPD patients with GOLD stages II and III inhaled a radiolabeled marker dissolved in water via a trans-nasal route. The mean aerosol particle size was 5.5 µm. Each patient took part in two inhalation sessions that included two application methods and were at least 70 hours apart. During the first session ("passive method"), the patient inhaled the aerosol through an open tube system. The second session ("active method") included pressure support ventilation during the inhalation process. A gamma camera and planar scintigraphy was used to determine the distribution of aerosol particles in the patient's body and lung. RESULTS: The pressure supported inhalation ("active method") results in an increased aerosol lung deposition compared to the passive method. Above all, we could demonstrate deposition in the lung periphery with relatively large aerosol particles (5.5 µm). DISCUSSION: The results prove that the combination of trans-nasal inhalation with noninvasive pressure support ventilation leads to significantly increased particle deposition in the lung.


Assuntos
Administração por Inalação , Pulmão/metabolismo , Respiração com Pressão Positiva/instrumentação , Doença Pulmonar Obstrutiva Crônica/metabolismo , Radioisótopos/administração & dosagem , Radioisótopos/farmacocinética , Aerossóis , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nariz , Tamanho da Partícula , Projetos Piloto , Respiração com Pressão Positiva/métodos , Distribuição Tecidual
12.
Rofo ; 187(5): 372-9, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25962672

RESUMO

PURPOSE: To investigate whether the effects of hybrid iterative reconstruction (HIR) on coronary artery calcium (CAC) measurements using the Agatston score lead to changes in assignment of patients to cardiovascular risk groups compared to filtered back projection (FBP). MATERIALS AND METHODS: 68 patients (mean age 61.5 years; 48 male; 20 female) underwent prospectively ECG-gated, non-enhanced, cardiac 256-MSCT for coronary calcium scoring. Scanning parameters were as follows: Tube voltage, 120 kV; Mean tube current time-product 63.67 mAs (50 - 150 mAs); collimation, 2 × 128 × 0.625 mm. Images were reconstructed with FBP and with HIR at all levels (L1 to L7). Two independent readers measured Agatston scores of all reconstructions and assigned patients to cardiovascular risk groups. Scores of HIR and FBP reconstructions were correlated (Spearman). Interobserver agreement and variability was assessed with ĸ-statistics and Bland-Altmann-Plots. RESULTS: Agatston scores of HIR reconstructions were closely correlated with FBP reconstructions (L1, R = 0.9996; L2, R = 0.9995; L3, R = 0.9991; L4, R = 0.986; L5, R = 0.9986; L6, R = 0.9987; and L7, R = 0.9986). In comparison to FBP, HIR led to reduced Agatston scores between 97 % (L1) and 87.4 % (L7) of the FBP values. Using HIR iterations L1 - L3, all patients were assigned to identical risk groups as after FPB reconstruction. In 5.4 % of patients the risk group after HIR with the maximum iteration level was different from the group after FBP reconstruction. CONCLUSION: There was an excellent correlation of Agatston scores after HIR and FBP with identical risk group assignment at levels 1 - 3 for all patients. Hence it appears that the application of HIR in routine calcium scoring does not entail any disadvantages. Thus, future studies are needed to demonstrate whether HIR is a reliable method for reducing radiation dose in coronary calcium scoring.


Assuntos
Algoritmos , Calcinose/diagnóstico por imagem , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Medição de Risco/métodos , Sensibilidade e Especificidade
13.
Clin Radiol ; 70(1): 54-61, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25459197

RESUMO

AIM: To compare image quality and diagnostic confidence of 100 kVp CT pulmonary angiography (CTPA) in patients with body weights (BWs) below and above 100kg. MATERIALS AND METHODS: The present retrospective study comprised 216 patients (BWs of 75-99kg, 114 patients; 100-125kg, 88 patients; >125kg, 14 patients), who received 100 kVp CTPA to exclude pulmonary embolism. The attenuation was measured and the contrast-to-noise ratio (CNR) was calculated in the pulmonary trunk. Size-specific dose estimates (SSDEs) were evaluated. Three blinded radiologists rated subjective image quality and diagnostic confidence. Results between the BW groups and between three body mass index (BMI) groups (BMI <25kg/m(2), BMI = 25-29.9kg/m(2), and BMI ≥30kg/m(2), i.e., normal weight, overweight, and obese patients) were compared using the Kruskal-Wallis test. RESULTS: Vessel attenuation was higher and SDDE was lower in the 75-99kg group than at higher BWs (p-values between <0.001 and 0.03), with no difference between the 100-125 and >125kg groups (p = 0.892 and 1). Subjective image quality and diagnostic confidence were not different among the BW groups (p = 0.225 and 1). CNR was lower (p < 0.006) in obese patients than in normal weight or overweight subjects. Diagnostic confidence was not different in the BMI groups (p = 0.105). CONCLUSION: CTPA at 100 kVp tube voltage can be used in patients weighing up to 125kg with no significant deterioration of subjective image quality and confidence. The applicability of 100 kVp in the 125-150kg BW range needs further testing in larger collectives.


Assuntos
Angiografia/normas , Sobrepeso/diagnóstico por imagem , Artéria Pulmonar/diagnóstico por imagem , Tomografia Computadorizada por Raios X/normas , Adulto , Idoso , Angiografia/métodos , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/diagnóstico por imagem , Embolia Pulmonar/diagnóstico por imagem , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos
14.
J Cardiovasc Surg (Torino) ; 55(5): 563-79, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24975736

RESUMO

Endovascular aortic repair (EVAR) necessitates lifelong surveillance for the patient, in order to detect complications timely. Endoleaks (ELs) are among the most common complications of EVAR. Especially type II ELs can have a very unpredictable clinical course and this can range from spontaneous sealing to aortic rupture. Subgroups of this type of EL need to be identified in order to make a proper risk stratification. Aim of this review is to describe the existing imaging techniques, including their advantages and disadvantages in the context of post-EVAR surveillance with a particular emphasis on low-flow ELs. Low flow ELs cause pressurization of the aortic aneurysm sac with a low velocity filling, leading to difficulty of detection by routine imaging protocols for EVAR surveillance, e.g. bi- or triphasic multislice computed tomographic angiography, magnetic resonance imaging and contrast enhanced ultrasound. In this article, we review the imaging possibilities of ELs and discuss the different imaging strategies available for depicting low flow ELs.


Assuntos
Aorta/cirurgia , Aneurisma Aórtico/cirurgia , Implante de Prótese Vascular/efeitos adversos , Diagnóstico por Imagem/métodos , Endoleak/diagnóstico , Procedimentos Endovasculares/efeitos adversos , Angiografia Digital , Aorta/fisiopatologia , Aorta/ultraestrutura , Aneurisma Aórtico/diagnóstico , Aneurisma Aórtico/fisiopatologia , Aortografia , Meios de Contraste , Endoleak/etiologia , Endoleak/fisiopatologia , Hemodinâmica , Humanos , Angiografia por Ressonância Magnética , Valor Preditivo dos Testes , Tomografia Computadorizada por Raios X , Ultrassonografia Doppler Dupla
15.
Swiss Med Wkly ; 144: w13923, 2014 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-24554399

RESUMO

PRINCIPLES: Computed tomography (CT) is inferior to the fibroscan and laboratory testing in the noninvasive diagnosis of liver fibrosis. On the other hand, CT is a frequently used diagnostic tool in modern medicine. The auxiliary finding of clinically occult liver fibrosis in CT scans could result in an earlier diagnosis. The aim of this study was to analyse quantifiable direct signs of liver remodelling in CT scans to depict liver fibrosis in a precirrhotic stage. METHODS: Retrospective review of 148 abdominal CT scans (80 liver cirrhosis, 35 precirrhotic fibrosis and 33 control patients). Fibrosis and cirrhosis were histologically proven. The diameters of the three main hepatic veins were measured 1-2 cm before their aperture into the inferior caval vein. The width of the caudate and the right hepatic lobe were divided, and measured horizontally at the level of the first bifurcation of the right portal vein in axial planes (caudate-right-lobe ratio). A combination of both (sum of liver vein diameters divided by the caudate-right lobe ratio) was defined as the ld/crl ratio. These metrics were analysed for the detection of liver fibrosis and cirrhosis. RESULTS: An ld/crl-r <24 showed a sensitivity of 83% and a specificity of 76% for precirrhotic liver fibrosis. Liver cirrhosis could be detected with a sensitivity of 88% and a specificity of 82% if ld/crl-r <20. CONCLUSION: An ld/crl-r <24 justifies laboratory testing and a fibroscan. This could bring forward the diagnosis and patients would profit from early treatment in a potentially reversible stage of disease.


Assuntos
Cirrose Hepática/diagnóstico por imagem , Fígado/diagnóstico por imagem , Fígado/patologia , Tomografia Computadorizada por Raios X , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Fibrose/diagnóstico por imagem , Fibrose/patologia , Veias Hepáticas/diagnóstico por imagem , Veias Hepáticas/patologia , Humanos , Cirrose Hepática/patologia , Masculino , Conceitos Matemáticos , Pessoa de Meia-Idade , Tamanho do Órgão , Veia Porta/diagnóstico por imagem , Veia Porta/patologia , Estudos Retrospectivos , Sensibilidade e Especificidade
16.
Rofo ; 186(7): 661-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24477507

RESUMO

Nephrogenic systemic fibrosis (NSF) is a serious, sometimes fatal disease. Findings in recent years have shown that a causal association between gadolinium containing contrast media and NSF is most likely. Therefore, the regulatory authorities have issued guidelines on the use of gadolinium-containing contrast media which have reduced the number of new cases of NSF to almost zero. However, it is for precisely this reason that the greatest care must still be taken to ensure that these guidelines are complied with. The most important factors are renal function, the quantity of gadolinium administered and coexisting diseases such as inflammation. All of these factors crucially influence the quantity of gadolinium released from the chelat in the body. This free gadolinium is thought to be the trigger for NSF. Other important factors are the stability of the gadolinium complex and furthermore the route of its elimination from the body. Partial elimination via the liver might be an additional protective mechanism. In conclusion, despite the NSF risk, contrast-enhanced MRI is a safe diagnostic procedure which can be used reliably and safely even in patients with severe renal failure, and does not necessarily have to be replaced by other methods.


Assuntos
Gadolínio/efeitos adversos , Imageamento por Ressonância Magnética/efeitos adversos , Imageamento por Ressonância Magnética/normas , Dermopatia Fibrosante Nefrogênica/induzido quimicamente , Dermopatia Fibrosante Nefrogênica/prevenção & controle , Guias de Prática Clínica como Assunto , Meios de Contraste/efeitos adversos , Medicina Baseada em Evidências , Humanos , Dermopatia Fibrosante Nefrogênica/diagnóstico , Fatores de Risco
17.
Eur J Vasc Endovasc Surg ; 47(1): 28-36, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24183247

RESUMO

OBJECTIVE: We evaluated the feasibility of visceral artery and lumbar artery (LA) embolization using AMPLATZER vascular plug (AVP) types 4 and 2 (AVP4, AVP2) prior to endovascular aneurysm repair (EVAR) to prevent the development of a type II endoleak. METHODS: Between January 2008 and April 2010, 45 arteries in 33 male patients were embolized with 44 AVP4 and one AVP2. Artery name and diameter; device number and size; and intervention, fluoroscopy, and deployment times for each procedure and each device were recorded. Computed tomography (CT) angiography was performed 2 days and 3, 6, 12, 18, 24, and 36 months after EVAR to confirm successful EVAR and embolotherapy, exclude endoleaks, and evaluate aneurysm shrinkage. RESULTS: AVP4 devices were implanted into the inferior mesenteric arteries in 33 cases, lumbar arteries in seven cases, and pelvic and renal arteries in two cases each. An AVP2 device was inserted into the gluteal artery in one case. The success rate was 100%, with total occlusion of all target vessels. No endoleaks were found in follow-up CT angiography. CONCLUSION: The use of AVP prior to EVAR is an efficient embolization technique that prevents the development of type II endoleaks.


Assuntos
Aneurisma/terapia , Implante de Prótese Vascular/efeitos adversos , Embolização Terapêutica/instrumentação , Endoleak/prevenção & controle , Procedimentos Endovasculares/efeitos adversos , Vértebras Lombares/irrigação sanguínea , Vísceras/irrigação sanguínea , Idoso , Idoso de 80 Anos ou mais , Aneurisma/diagnóstico por imagem , Aneurisma/cirurgia , Angiografia Digital , Endoleak/diagnóstico por imagem , Endoleak/etiologia , Desenho de Equipamento , Estudos de Viabilidade , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento
18.
Eur J Radiol ; 82(12): e873-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24074648

RESUMO

OBJECTIVES: To find the best pairing of first and second reader at highest sensitivity for detecting lung nodules with CT at various dose levels. MATERIALS AND METHODS: An anthropomorphic lung phantom and artificial lung nodules were used to simulate screening CT-examination at standard dose (100 mAs, 120 kVp) and 8 different low dose levels, using 120, 100 and 80 kVp combined with 100, 50 and 25 mAs. At each dose level 40 phantoms were randomly filled with 75 solid and 25 ground glass nodules (5-12 mm). Two radiologists and 3 different computer aided detection softwares (CAD) were paired to find the highest sensitivity. RESULTS: Sensitivities at standard dose were 92%, 90%, 84%, 79% and 73% for reader 1, 2, CAD1, CAD2, CAD3, respectively. Combined sensitivity for human readers 1 and 2 improved to 97%, (p1=0.063, p2=0.016). Highest sensitivities--between 97% and 99.0%--were achieved by combining any radiologist with any CAD at any dose level. Combining any two CADs, sensitivities between 85% and 88% were significantly lower than for radiologists combined with CAD (p<0.03). CONCLUSIONS: Combination of a human observer with any of the tested CAD systems provide optimal sensitivity for lung nodule detection even at reduced dose at 25 mAs/80 kVp.


Assuntos
Detecção Precoce de Câncer/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Competência Profissional , Doses de Radiação , Software , Nódulo Pulmonar Solitário/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Relação Dose-Resposta à Radiação , Detecção Precoce de Câncer/instrumentação , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Reconhecimento Automatizado de Padrão , Imagens de Fantasmas , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Validação de Programas de Computador , Tomografia Computadorizada por Raios X/instrumentação
20.
Fam Cancer ; 12(1): 89-96, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23179793

RESUMO

Most screening programs for familial pancreatic cancer are currently based on endoscopic ultrasonography and/or magnetic resonance imaging (MRI). Cystic lesions, especially those suspicious for small intraductal pancreatic mucinous neoplasms (IPMNs) of the branch ducts, can be visualized in up to 40 % of individuals at risk, but their pathological importance in the setting of FPC is yet not well established. Individuals at risk from a prospective screening program for familial pancreatic cancer with small "imaging" IPMNs of the branch-duct type (BD-IPMN) who underwent pancreatic resection were analysed regarding clinico-pathological data and the locations of pancreatic lesions. Five of 125 individuals at risk who underwent screening had multiple small (size 2-10 mm) unicystic lesions and/or multicystic single lesions in the pancreatic body and tail suspicious for BD-IPMNs upon MRI imaging and decided to undergo surgical resection after interdisciplinary counselling, although none fulfilled the consensus criteria for IPMN resection. Histological examination revealed BD-IPMNs with low or moderate dysplasia of the gastric type in combination with multifocal PanIN2 and PanIN3 lesions in 4 individuals. The remaining patient had only tiny ductectasias in the pancreatic tail with multifocal PanIN 2 lesions in the entire gland and one PanIN3 lesion in the pancreatic head. Intriguingly, the location of the most dysplastic histological lesions (PanIN3) did not correspond to the preoperatively detected lesions and were not visible in preoperative imaging. In the setting of FPC, the presence of multiple small "imaging" BD-IPMNs may indicate the presence of high-grade PanIN lesions elsewhere in the pancreas.


Assuntos
Adenocarcinoma Mucinoso/patologia , Carcinoma in Situ/patologia , Carcinoma Ductal Pancreático/patologia , Carcinoma Papilar/patologia , Carcinoma/patologia , Detecção Precoce de Câncer/métodos , Pâncreas/patologia , Neoplasias Pancreáticas/patologia , Adenocarcinoma Mucinoso/cirurgia , Idoso , Carcinoma/cirurgia , Carcinoma in Situ/cirurgia , Carcinoma Ductal Pancreático/cirurgia , Carcinoma Papilar/cirurgia , Endossonografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Neoplasias Pancreáticas/cirurgia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...