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1.
Ultraschall Med ; 36(6): 603-10, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26565516

RESUMO

PURPOSE: Hepatic vein pressure gradient (HVPG) is the gold standard for diagnosing clinically significant portal hypertension (CSPH). The aim of this study was to investigate-in comparison to HVPG-the ability to diagnose CSPH by liver and spleen stiffness measurements obtained by acoustic radiation force impulse (ARFI) imaging. MATERIALS AND METHODS: A total of 78 patients (mean age: 53 ±â€Š13 years, 62 % male) with chronic liver disease were enrolled in this study. Each patient received liver (LSM) and spleen (SSM) stiffness measurements by ARFI, an HVPG measurement and a transjugular liver biopsy on the same day. Patients were classified according to their HVPG into three different groups: HVPG < 10 mmHg, HVPG ≥ 10-< 12 mmHg and HVPG ≥ 12 mmHg. RESULTS: LSM, SSM were significantly higher in patients with HVPG ≥ 10 - < 12 in comparison to HVPG < 10 mmHg (p < 0.001 and p < 0.001, respectively), and in patients with HVPG ≥ 12 mmHg in comparison to ≥ 10 - < 12 mmHg (p < 0.001 and p < 0.001, respectively). LSM and SSM were able to diagnose HVPG ≥ 10 mmHg and HVPG ≥ 12 mmHg with high diagnostic performance (AUC LSM: 0.93 and 0.87, respectively; AUC SSM: 0.97 and 0.95, respectively). The AUC of SSM in predicting esophageal varices (EVs) plus HVPG ≥ 10 mmHg and EVs plus HVPG ≥ 12 mmHg were higher compared to LSM in both groups of patients (SSM: 0.90 and 0.93 vs. LSM: 0.84 and 0.88, respectively). No significant difference between both AUCs was detected in the different HVPG groups. In the multivariate -analysis SSM remained a factor predicting HVPG (HVPG > 10 mmHg p = 0.007; HVPG ≥ 12 mmHg p = 0.003). CONCLUSION: LSM and SSM by ARFI are noninvasive diagnostic tools that may help in diagnosing CSPH. LSM and SSM could be used as a guiding noninvasive screening tool in patients with esophageal varices requiring endoscopic evaluation.


Assuntos
Técnicas de Imagem por Elasticidade , Hipertensão Portal/diagnóstico por imagem , Fígado/diagnóstico por imagem , Baço/diagnóstico por imagem , Adulto , Idoso , Fenômenos Biomecânicos , Estudos de Coortes , Estudos Transversais , Feminino , Veias Hepáticas/diagnóstico por imagem , Humanos , Biópsia Guiada por Imagem , Fígado/patologia , Cirrose Hepática/diagnóstico por imagem , Cirrose Hepática/patologia , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Pressão na Veia Porta/fisiologia , Sensibilidade e Especificidade
2.
Ultraschall Med ; 36(3): 239-47, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25970201

RESUMO

PURPOSE: The aim of the present prospective European multicenter study was to demonstrate the non-inferiority of point shear wave elastography (pSWE) compared to transient elastography (TE) for the assessment of liver fibrosis in patients with chronic hepatitis C. MATERIALS AND METHODS: 241 patients with chronic hepatitis C were prospectively enrolled at 7 European study sites and received pSWE, TE and blood tests. Liver biopsy was performed with histological staging by a central pathologist. In addition, for inclusion of cirrhotic patients, a maximum of 10 % of patients with overt liver cirrhosis confirmed by imaging methods were allowed by protocol (n = 24). RESULTS: Owing to slower than expected recruitment due to a reduction of liver biopsies, the study was closed after 4 years before the target enrollment of 433 patients with 235 patients in the 'intention to diagnose' analysis and 182 patients in the 'per protocol' analysis. Therefore, the non-inferiority margin was enhanced to 0.075 but non-inferiority of pSWE could not be proven. However, Paired comparison of the diagnostic accuracy of pSWE and TE revealed no significant difference between the two methods in the 'intention to diagnose' and 'per protocol' analysis (0.81 vs. 0.85 for F ≥ 2, p = 0.15; 0.88 vs. 0.92 for F ≥ 3, p = 0.11; 0.89 vs. 0.94 for F = 4, p = 0.19). Measurement failure was significantly higher for TE than for pSWE (p = 0.030). CONCLUSION: Non-inferiority of pSWE compared to TE could not be shown. However, the diagnostic accuracy of pSWE and TE was comparable for the noninvasive staging of liver fibrosis in patients with chronic hepatitis C.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Hepatite C Crônica/diagnóstico por imagem , Cirrose Hepática/diagnóstico por imagem , Adulto , Idoso , Biópsia , Feminino , Hepatite C Crônica/patologia , Humanos , Fígado/diagnóstico por imagem , Fígado/patologia , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e Especificidade , Adulto Jovem
3.
Internist (Berl) ; 53(3): 261-70, 2012 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-22349171

RESUMO

Abdominal ultrasonography is an essential tool for physicians. In contrast to other imaging methods, ultrasound examination is a cost-effective real-time imaging method without radiation effects. As in all other imaging methods, abdominal ultrasound requires an experienced examiner and high quality equipment to maintain a high quality. Abdominal ultrasonography is at least equal to cross-sectional imaging methods in most clinical issues, e.g., in inflammatory bowel disease, vascular liver diseases, or real-time surveillance of interventions. The range of applications for ultrasound has been markedly expanded by using contrast-enhanced ultrasound to detect and characterize space occupying lesions or perfusion aberrations in- and outside the liver.Ultrasound-guided fine needle aspiration biopsy or drainage of space occupying lesions and pathological liquids are minimally invasive standard ultrasound-guided interventions. Ultrasound-based tumor therapy as well as sclerotherapy of symptomatic nonparasitic cysts of the liver, kidneys, or spleen are also performed. By being able to provide quantitatively reproducible measurement of tissue stiffness, ultrasonography has entered a new era. The development of mechanical elastography also promises a new form of tissue characterization.


Assuntos
Abdome/diagnóstico por imagem , Biópsia/métodos , Cirurgia Assistida por Computador/métodos , Ultrassonografia de Intervenção/métodos , Humanos
4.
Ultraschall Med ; 32 Suppl 2: E24-30, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22194051

RESUMO

PURPOSE: To date, the use of transient elastography has been limited to the liver. Acoustic radiation force impulse imaging (ARFI) is a new technology offering elastography of different tissues. Here, we present initial spleen elastography data and evaluate its influencing factors, especially portal hypertension. MATERIALS AND METHODS: Elastography of the spleen and liver using the ARFI method was performed in 30 patients with portal hypertension, 70 patients with chronic liver disease without portal hypertension and 25 healthy controls. RESULTS: ARFI elastography of the spleen was feasible in 99% of patients and valid in 78%. The mean propagation velocity inside the spleen was 2.95 ± 0.60 m/sec, thus much higher than in the normal liver (< 1.10 m/sec). Spleen stiffness was higher in the patients with portal hypertension (p < 0.008) but did not correlate to spleen size. Spleen stiffness increased with patient age and liver stiffness (both p < 0.0001) as confirmed by multivariate analysis (R2 = 0.19, p < 0.01). In ROC analysis, spleen elastography was inferior to liver elastography for the detection of portal hypertension (area under the curve 0.68 vs. 0.90). CONCLUSION: The new ARFI method allows accurate elastography of the spleen. The stiffness of the normal spleen is much higher than that of the normal liver and increases with age. However, spleen elastography is inferior to liver elastography for the detection of portal hypertension.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Hipertensão Portal/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Cirrose Hepática/diagnóstico por imagem , Hepatopatias/diagnóstico por imagem , Fígado/diagnóstico por imagem , Baço/diagnóstico por imagem , Adulto , Idoso , Técnicas de Imagem por Elasticidade/instrumentação , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/instrumentação , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Valores de Referência , Sensibilidade e Especificidade
5.
Z Gastroenterol ; 48(11): 1279-84, 2010 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-21043005

RESUMO

Teaching ultrasound (US) has not been sufficiently standardised yet. Most educational devices in US consist of 2-dimensional B-mode images. However, the identification of anatomic structures in the 3-dimensional space can only be learned by practical hands-on education. In US simulators, US images of real pathologies are created by the examination of a dummy with a mock transducer. The resulting US images were previously recorded in a 3-dimensional format and were processed in a way which facilitates the reconstruction and projection of the images on a screen corresponding to the sectional plane of the mock transducer, simulating the conventional B-mode images. This enables standardised, real-time, hands-on training of US pathology detection. In June 2007, a hands-on workshop on US simulators was performed in the 1st Department of Internal Medicine of the Johannes Gutenberg-University in Mainz/Germany. During 15 days, 209 participants from all parts of Germany were trained. The workshop included an evaluation to elucidate the value and acceptance of this kind of US training. 149 evaluation forms could be analysed (72 %). The participants were fairly heterogeneous and belonged to the following subspecialties: internal medicine (50 %), surgery (11 %), others (18 %). 72 % were residents, 22 % consultants. 40 % of the participants worked in university hospitals, 12 % in hospitals of highest clinical level, and 42 % in hospital of basic care. Baseline knowledge in US was quite different, too, reflected in the number of independently performed US examinations prior to this course: 0 - 400 examinations (44 %), 401 - 1000 examinations (14 %), 1001 - 4000 examinations (7 %), and > 4000 examinations (2 %). Of note, 56 % of the participants had not received any kind of formal training in US. In daily practice 77 % were trained by tutors, whose formal qualification in US was unknown. Only a small proportion of the tutors had received training in US according to the standards of the German Association of US in Medicine (DEGUM). This evaluation shows the high level of acceptance of simulator-based training in US despite the heterogeneity of the participants. 95 % rated the teaching value as "high" and 95 % wished an integration of US simulators in training curricula. In summary, this analysis proves the need for standardised training programmes in US teaching in Germany and a high level of acceptance of simulator-based US training.


Assuntos
Instrução por Computador/métodos , Instrução por Computador/estatística & dados numéricos , Currículo/estatística & dados numéricos , Educação Médica/estatística & dados numéricos , Ultrassonografia/estatística & dados numéricos , Interface Usuário-Computador , Avaliação Educacional , Alemanha
6.
Z Gastroenterol ; 48(6): 688-92, 2010 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-20140843

RESUMO

Intestinal intussusception in the adult is often idiopathic but also known to be associated with chronic inflammatory bowel disease, coeliac disease, tumours or previous abdominal operations. A 22-year-old women after liver transplantation due to Crigler Najar Syndrome suffered from repeated episodes of abdominal pain. The diagnosis of repeated self-limited intestinal intussusceptions was made by computed tomography and ultrasonography. A laparoscopy revealed no cause for the intussusceptions. During a new episode of abdominal pain caused again by an intussusception a colonoscopy was performed that showed aspects of a discreet colitis. In the biopsies CMV was detected by qualitative PCR, while blood tests for CMV pp65 antigen were negative. A therapy with gancyclovir was initiated which lead to remission of the patient's symptoms. A colonoscopy six weeks later showed a completely normal colon, while in the biopsies CMV was not detectable. After a follow-up of one year the patient has not suffered from any further episodes. This case demonstrates the role of chronic intestinal CMV infection as a possible causative factor for repeated intussusceptions in immunosuppressed patients. Whenever possible a PCR for CMV in colon biopsies should be carried out to detect an intestinal CMV infection because as shown in our case results for immunohistopathology and CMV pp65 can be negative despite a chronic infection.


Assuntos
Infecções por Citomegalovirus/complicações , Infecções por Citomegalovirus/microbiologia , Citomegalovirus/isolamento & purificação , Enterocolite/etiologia , Enterocolite/microbiologia , Intussuscepção/etiologia , Transplante de Fígado/efeitos adversos , Citomegalovirus/genética , Enterocolite/diagnóstico , Feminino , Humanos , Intussuscepção/microbiologia , Adulto Jovem
7.
Occup Environ Med ; 65(3): 191-6, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17881467

RESUMO

OBJECTIVES: To examine the risk of wood dust and chemical exposures for adenocarcinoma of the nasal cavity and paranasal sinuses (ADCN) among German wood workers. METHODS: An industry-based case-control study with 86 male ADCN cases and 204 controls was conducted in the German wood-working industries. Cumulative and average wood-dust exposure was quantified with a job-exposure matrix based on wood-dust measurements at recent and historical workplaces. Probabilities of exposure to wood preservatives, stains, varnishes, and formaldehyde were semi-quantitatively rated. Odds ratios and 95% confidence intervals were calculated with logistic regression analysis conditional on age and adjusted for smoking and other factors. For estimating the risks of either wood dust or chemical additives, the authors additionally adjusted for the corresponding co-exposure. RESULTS: ADCN occurred relatively more frequently among wood workers that had ever worked as cabinet makers or joiners (OR 2.96, 95% CI 1.46 to 6.01) than as saw millers (OR 0.15, 95% CI 0.03 to 0.68). Average exposure to inhalable wood dust >/=5 mg/m(3) was associated with a high risk (OR 48.47, 95% CI 13.30 to 176.63) compared to levels below 3.5 mg/m(3). Assuming 40 years of exposure under these concentrations, the corresponding OR was 4.20 (95% CI 1.69 to 10.43). Exposure between 3.5 and 5 mg/m(3) was also found to pose a risk (OR 10.54, 95% CI 3.34 to 33.27). Exposure to pigment stains before 1970 was associated with an increased risk (OR 3.03; 95% CI 1.11 to 8.26). No significant associations were estimated for wood preservatives, varnishes, and formaldehyde. CONCLUSIONS: The authors found an elevated ADCN risk for exposure to inhalable wood dust above 3.5 mg/m(3). The rareness of the disease does not allow the exclusion of risk below that concentration. For pigment stains, there is evidence for an association of historical exposure with the development of ADCN in German wood workers.


Assuntos
Adenocarcinoma/epidemiologia , Indústrias , Neoplasias Nasais/epidemiologia , Doenças Profissionais/epidemiologia , Exposição Ocupacional , Madeira , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Poluentes Ocupacionais do Ar , Estudos de Casos e Controles , Poeira , Alemanha , Humanos , Exposição por Inalação , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Pintura , Neoplasias dos Seios Paranasais/epidemiologia , Medição de Risco/métodos , Fumar/efeitos adversos
8.
Aliment Pharmacol Ther ; 44(4): 366-79, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27363528

RESUMO

BACKGROUND: Obesity and overweight are global health problems. AIM: To evaluate the diagnostic accuracy of liver stiffness measurement (LSM) using acoustic radiation force impulse (ARFI) elastography in overweight and obese patients for staging liver fibrosis. METHODS: Ninety-seven patients (mean age: 50 years, 50% male) with body mass index (BMI) ≥25 kg/m(2) (mean BMI: 31 kg/m(2) ) were prospectively enrolled. All patients underwent ARFI elastography and liver biopsy. In 87/97 patients, transient elastography (TE) was performed (M- and XL-probes). Patients were divided into two groups respectively: overweight: BMI <30 kg/m(2) (n = 61); and obese: BMI ≥30 kg/m(2) (n = 26). RESULTS: Acoustic radiation force impulse elastography correlated with liver fibrosis in overweight (r = 0.84, P < 0.0001) and obese patients (r = 0.85, P < 0.0001), while no correlation was observed with steatosis, steatohepatitis and BMI. Area under the curve detecting liver cirrhosis for ARFI and TE were 0.97 in overweight and 0.94 and 0.92 in obese patients. In both groups, the failure rate was lower for ARFI than TE. ARFI of liver segment 8 showed a lower discordance than TE in both groups (overweight: 3% vs. 12%, P = 0.002; obese: 8% vs. 27%, P = 0.034). Steatosis and steatohepatitis were neither predictors of discordance nor of performance in LSM by ARFI or TE in both groups. CONCLUSIONS: In overweight and obese patients, acoustic radiation force impulse can diagnose liver cirrhosis and significant fibrosis with high diagnostic accuracy. Liver stiffness measurement using the XL-probe reduces the influence of BMI, steatosis and steatohepatitis. The failure and discordance rates were lower for acoustic radiation force impulse than transient elastography in both patients groups.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Cirrose Hepática/diagnóstico por imagem , Sobrepeso/diagnóstico por imagem , Adulto , Biópsia , Fígado Gorduroso/diagnóstico por imagem , Fígado Gorduroso/patologia , Feminino , Humanos , Fígado/patologia , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-Idade , Sobrepeso/patologia
9.
Oncol Rep ; 33(1): 81-7, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25333302

RESUMO

Fine needle aspiration (FNA) is a sensitive and specific method (95%), often helpful in characterizing suspected liver lesions. It is appropriate to distinguish between primary and secondary liver neoplasia. Moreover, in most cases, the use of cell block preparations of small specimens allows immunocytochemical evaluation to determine the nature of the primary tumour. In a retrospective study at Hannover Medical School (MHH) from 1998 to 2012 (14 years), 4,136 sonographically guided FNAs were performed. The patients provided consent and the study protocol was approved by the local ethics committee. There were 39.6% malignant and 57.5% benign lesions in the liver, while 2.8% of the cases were undetermined. FNA was non-representative in 1.1% of the cases. The diagnostic utility of highly differentiated hepatocellular carcinoma (HCC; G1) remains difficult; cell bridges with cell atypia are pathognomonic for diagnosis. Ancillary techniques and immunocytochemical investigations will increase the sensitivity and specificity, particularly by using the cell block technique.


Assuntos
Neoplasias Hepáticas/diagnóstico , Fígado/patologia , Neoplasias dos Ductos Biliares/diagnóstico , Biópsia por Agulha Fina , Humanos , Neoplasias Hepáticas/secundário , Tumores Neuroendócrinos/diagnóstico , Sensibilidade e Especificidade
10.
Am J Clin Pathol ; 94(1): 95-101, 1990 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2193510

RESUMO

A 26-year-old woman who had undergone orthotopic heart transplantation because of dilative cardiomyopathy received a triple-drug immunosuppressive regimen (cyclosporine A, azathioprine, and prednisolone). During her relatively frequent episodes of acute rejection, she was treated with methylprednisolone and repeated application of ATG. A short time before the patient's death, a fine-needle aspiration of the liver revealed the cytologic diagnosis of a malignant pleomorphic medium-size cell non-Hodgkin's lymphoma of a higher grade of malignancy. Immunosuppression was reduced, and the patient died in cardiogenic shock related to a histologically confirmed episode of severe acute rejection 264 days after the transplantation. On autopsy, the malignant lymphoma previously diagnosed by fine-needle aspiration cytology was found to be present in the liver as the only extranodal localization. The immunohistologic analysis of the immunophenotype specified the lymphomatous neoplasia as a T-cell lymphoma. The particular importance of this case is that it is, to our knowledge, the third case of proven T-cell lymphoma following organ grafting documented in the literature and the first case described in a cardiac allograft recipient.


Assuntos
Transplante de Coração/efeitos adversos , Neoplasias Hepáticas/etiologia , Linfoma não Hodgkin/etiologia , Adulto , Feminino , Humanos , Técnicas Imunoenzimáticas , Terapia de Imunossupressão , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Linfoma não Hodgkin/genética , Linfoma não Hodgkin/metabolismo , Linfoma não Hodgkin/patologia , Hibridização de Ácido Nucleico , Fenótipo , Linfócitos T/imunologia , Linfócitos T/metabolismo
11.
Best Pract Res Clin Gastroenterol ; 15(1): 21-39, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11355899

RESUMO

Vascular disorders of the gastrointestinal tract include a variety of different underlying diseases, thus requiring different and, in many cases, more than one imaging procedure. Only a knowledge of the newest developments in vascular imaging techniques with all the possibilities and limits will ensure a time- and cost-effective, accurate and reliable diagnosis. In many acute cases and also as a screening procedure, ultrasound in combination with colour Doppler and duplex sonography, plays an important role in setting the right course for further imaging techniques, and can provide the correct diagnosis in many cases.Depending on the most prominent symptoms and the expected disease, the right choice of technique saves valuable time. Computed tomography (CT) and magnetic resonance imaging (MRI) are cross-sectional imaging techniques that not only demonstrate lesion vascularization, but also provide information about neighbouring structures and complications in an understandable and demonstrable way. The use of angiography as an invasive tool should be limited to cases where a high temporal and spatial resolution is necessary to make the diagnosis or where therapeutic interventions are also likely to be performed within the same setting. For the diagnosis of gastrointestinal vascular diseases, often no generally valid recommendation can be given, since the impact of all imaging techniques will depend on the examiner's experience, the technical equipment and on their 24-h availability in a hospital. This chapter tries to give some information about the inherent limits and indications of the different imaging techniques, as well as the newest study results concerning the most frequent vascular diseases of the gastrointestinal tract.


Assuntos
Diagnóstico por Imagem/métodos , Sistema Digestório/irrigação sanguínea , Doenças Vasculares/diagnóstico , Angiografia/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X , Ultrassonografia Doppler/métodos
12.
Ann Thorac Surg ; 57(5): 1263-6, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-7513990

RESUMO

Palliative intubation of the esophagus for a malignant tracheoesophageal fistula is often complicated by difficulty in obtaining a tight seal. We have overcome the problem in three instances by placing a bifurcated, foam-cuffed stent in the trachea.


Assuntos
Stents , Fístula Traqueoesofágica/terapia , Idoso , Neoplasias Esofágicas/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Paliativos , Radiografia , Fístula Traqueoesofágica/diagnóstico por imagem , Fístula Traqueoesofágica/etiologia
13.
Clin Nutr ; 12(5): 287-92, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16843328

RESUMO

UNLABELLED: 14 patients in advanced stages of HIV infection (1 ARC, 13 AIDS; sex: 1 female, 13 male; age 37.8 +/- 6.3 years; body mass index (BMI): 17.4 +/- 2.4 kg/m(2)) were followed prospectively while receiving home enteral nutrition (observation period: 62 +/- 75 days). Artificial nutrition was indicated because of severe weight loss (9-38 kg within 6-48 months, n = 7) or cerebral toxoplasmosis with eating and swallowing disorders (n = 7). In all patients a defined formula diet (175 +/- 17.7 kJ/kg body weight) was administered through an endoscopically placed gastrostomy tube (PEG). Home enteral nutrition was well tolerated by all patients and no significant PEG-related complications occurred. Enteral nutrition resulted in significant increases in body weight (p < 0.005), body cell mass (BCM, p < 0.05), total body fat (TBF, p < 0.005), serum albumin concentration (p < 0.05), and serum total iron-binding capacity (transferrin, p < 0.01). CONCLUSION: Home enteral nutrition via PEG is safe and well tolerated in patients with advanced HIV-related immunodeficiency and is capable of improving nutritional state including BCM.

14.
IEEE Trans Med Imaging ; 15(6): 796-801, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-18215959

RESUMO

Conventional two-dimensional (2-D) texture parameters serve as the "gold standard" of texture analysis. The authors compared a new stochastic model, based on autoregressive periodic random field models (APRFM) with conventional texture analysts (CTA) parameter, which were defined as measures of the co-occurrence matrix, i.e., entropy, contrast, correlation, uniformity, and maximum frequency. By fitting the model to a given texture pattern, the estimated model parameters are suitable texture features. In 81 patients, divided into patients without (N=19) and with (N=62) microfocal lesions of the liver, a set of 24 CTA and 16 APRFM parameters were calculated from ultrasonic liver images. To ensure simple computation the APRFM parameters were based on the unilateral type of pixel neighborhood. Regenerated texture by APRFM was visually comparable with the original texture. Reclassification analysis using the classification and regression tree (CART) discriminant analysis system and the area under the receiver operating characteristic (ROC) curve was used to assess the texture classification potency of APRFM- and CTA-parameters. Discriminating between liver with and without microfocal lesions, the best results were seen for the APRFM parameter.

15.
Clin Nephrol ; 53(5): 333-43, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-11305806

RESUMO

BACKGROUND: Renal artery disease can cause both hypertension and renal failure, and color Doppler sonography (CDS) may be a good screening method to detect it. Presently reported techniques of Doppler sonography have either a high rate of technical failure (4-42%), or low sensitivity and specificity, or detect only stenoses greater than 70%, or exclude patients with renal failure from analysis. In previous studies Doppler detection of renal artery stenosis (RAS) was based either on increased intrastenotic velocity or on the detection of post-stenotic Doppler phenomena. In the present prospective study these two approaches were combined to detect RAS (> or = 50% diameter reduction) in 226 consecutive patients (144 with normal and 82 with impaired renal function). METHODS: Stenosis of 50% or more was diagnosed if the maximal systolic velocity in the main renal artery was more than 180 cm/sec and velocity in the distal renal artery less than one quarter of the maximum velocity. When these velocities could not be determined a diagnosis of RAS was made when the acceleration time in intrarenal segmental arteries exceeded 70 msec. All patients subsequently underwent arteriography as the gold standard for the detection of RAS. RESULTS: With this combined approach, the technical failure rate of CDS was 0% in both patients with normal and those with impaired renal function. The mean time required for the Doppler investigation was 17 minutes. The sensitivity and specificity for detection of a significant stenosis in a given vessel (including accessory arteries), as compared to angiography, were 96.7% and 98.0%. CONCLUSION: Color Doppler sonography, evaluating both main renal and intrarenal arteries is an ideal screening method for detection of RAS of 50% or more because it allows accurate and rapid detection of stenosis in all patients, irrespective of renal function.


Assuntos
Obstrução da Artéria Renal/diagnóstico por imagem , Ultrassonografia Doppler em Cores , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Hipertensão Renovascular/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Radiografia , Artéria Renal/diagnóstico por imagem , Sensibilidade e Especificidade , Fatores de Tempo , Ultrassonografia Doppler em Cores/métodos
16.
Ultrasound Med Biol ; 20(6): 521-8, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7998373

RESUMO

In ultrasonic imaging an adaptive two-dimensional filter (ATDF) can suppress randomly generated speckle using the ratio of the local variance to the local mean as the speckle recognition feature (R). The degree of smoothing depends on the difference between the recognition feature in the region to be filtered and the selected reference tissue. We have investigated the clinical application of ATDF for ultrasound B-mode images of liver abnormalities. Using the R values of normal liver as reference values, the ATDF images were displayed. Normal livers (n = 17, R = 2.19 +/- 0.14 M +/- SEM), fatty livers (N = 16, R = 1.89 +/- 0.15) and those with acute hepatitis (N = 10, R = 2.25 +/- 0.18) appeared smooth after application of the adaptive filter, but those diseases with higher R values, such as chronic hepatitis (N = 10, R = 3.04 +/- 0.30), cirrhosis (n = 16, R = 4.44 +/- 0.30), metastases (N = 16, R = 6.43 +/- 0.53) and hepatocellular carcinomas (N = 8, R = 7.92 +/- 0.85), were largely unsmoothed. In conclusion, ATDF allows differentiation of some forms of liver disease and may be helpful in the detection of microfocal echogenic textural lesions.


Assuntos
Processamento de Imagem Assistida por Computador , Hepatopatias/diagnóstico por imagem , Ultrassonografia/métodos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência
17.
Acta Diabetol ; 30(4): 220-32, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8180414

RESUMO

This report shows that the cyclic AMP antagonist cyclic PIP is present in all organs and tissues of the rat so far examined: brain, heart, lung, intestine, kidney, liver, spleen, skeletal muscle and fat. The synthesis of cyclic PIP is stimulated by insulin or noradrenaline (alpha-adrenergic action) in a dose-dependent fashion. Increasing cyclic PIP synthesis with increasing insulin concentrations matches the insulin receptor binding curves. Cyclic PIP levels in blood serum remain low after hormonal stimulation and no cyclic PIP can be detected in urine. As an indication of its ubiquity, cyclic PIP was even detected in yeast. Prostaglandin E (as shown by incorporation of [3H]PGE into cyclic PIP and demonstration of a constant specific activity), myo-inositol (as shown by acid hydrolysis of the dephosphorylated cyclic PIP and mass spectrometric identification of the products) and one phosphate (as shown by the ionic nature of cyclic PIP and its inactivation by phosphodiesterase plus phosphatase) are components of cyclic PIP. Chemical derivatization experiments of cyclic PIP suggest the phosphate to be bound to myo-inositol and the myo-inositol phosphate to the prostaglandin E by its C15-hydroxyl group.


Assuntos
AMP Cíclico/antagonistas & inibidores , Fosfatos de Inositol/metabolismo , Fígado/metabolismo , Prostaglandinas E/metabolismo , Animais , Cromatografia de Afinidade , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Inositol/metabolismo , Fosfatos de Inositol/biossíntese , Fosfatos de Inositol/isolamento & purificação , Insulina/farmacologia , Fígado/efeitos dos fármacos , Masculino , Espectrometria de Massas , Norepinefrina/farmacologia , Especificidade de Órgãos , Fenilefrina/farmacologia , Fosfatos/metabolismo , Prostaglandinas E/biossíntese , Prostaglandinas E/isolamento & purificação , Ratos , Ratos Sprague-Dawley , Receptor de Insulina/metabolismo , Saccharomyces cerevisiae/metabolismo
18.
Eur J Radiol ; 4(1): 52-7, 1984 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6723674

RESUMO

Focal nodular hyperplasia of the liver (FNH) is a histologically defined benign hepatic tumour, possibly associated with the use of oral contraceptives. The present study deals with the question whether FNH can be distinguished from other lesions of the liver by ultrasonography alone or by a combination of real-time sonography and radiologic procedures. Therefore 18 cases of FNH, 16 females and 2 males, are presented. We retrospectively reviewed the diagnostic results of real-time sonography, hepatic scintigraphy, computed tomography with dynamic CT-densitometry, and angiography on these 18 patients. Ultrasonography enables the identification of the lesion in all of the 18 cases. FNH appears to show varying degrees of echogenicity (slight hypoechoic in 6 cases, isoechoic in 6 cases, and slight hyperechoic in 4 cases). In most of the patients the tumour had similar acoustic characteristics as the surrounding normal liver. By ultrasonography alone there is no possible differentiation of FNH from other hepatic tumours. Both the echo pattern of FNH and the results of the ultrasonically guided cytopuncture are unspecific.


Assuntos
Fígado/patologia , Ultrassonografia , Adolescente , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Hiperplasia , Fígado/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/diagnóstico por imagem , Masculino , Cintilografia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
19.
Rofo ; 130(3): 315-8, 1979 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-155573

RESUMO

The course of uncomplicated pancreatitis was followed by sonography in 45 patients. The changes during the disease and their temporal relationship to the clinical stage are illustrated by an example. During the initial phase of the disease the sonographic findings may be so slight that they are easily missed, although clinical symptoms are present. It is only during the main phase of the disease that the typical sonographic findings of acute pancreatitis develop. At this time, maximal increase in amylase activity has usually passed. During recovery, with uninterrupted clinical and biochemical improvement, changes in the sonogram can still be seen for between three weeks and four months.


Assuntos
Pancreatite/diagnóstico , Ultrassonografia , Doença Aguda , Adulto , Amilases/metabolismo , Ativação Enzimática , Feminino , Humanos , Pâncreas/enzimologia , Fatores de Tempo
20.
Rofo ; 133(2): 146-8, 1980 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-6449430

RESUMO

In order to check the value of sonography in the diagnosis of Crohn's disease, 81 patients who suffered from Crohn's disease were examined by means of real-time B-mode ultrasound. Bowel wall infiltration along the terminal ileum that could be shown to involve the coecum as well, appeared to be a reliable parameter in the diagnosis of Crohn's disease. This finding was most pronounced in acute disease whereas in chronic or mild disease, characteristic signs of Crohn's disease were absent. Among the complications of Crohn's disease formation of intraabdominal abscesses can be demonstrated by sonography. From our results we propose to employ diagnostic ultrasound in the acute stage of disease. After remission the diagnosis should be confirmed by endoscopy and X-ray examinations.


Assuntos
Doença de Crohn/diagnóstico , Ultrassonografia , Abscesso/diagnóstico , Doença Aguda , Doença de Crohn/diagnóstico por imagem , Endoscopia , Feminino , Humanos , Masculino , Radiografia
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