Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
2.
Cardiovasc Intervent Radiol ; 44(11): 1747-1748, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34476581

Assuntos
Consenso , Humanos
3.
Angiology ; 72(8): 724-732, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33779291

RESUMO

We evaluated the safety and efficacy of a resveratrol-paclitaxel-coated peripheral balloon catheter in an all-comer patient cohort undergoing endovascular treatment of above-the-knee and below-the-knee peripheral artery disease. CONSEQUENT ALL COMERS (Clinical Post-Market Clinical Follow-up [PMCF] on Peripheral Arteries treated with SeQuent Please OTW [Over-the Wire]) is a prospective, single-arm, multicenter observational study (ClinicalTrials Identifier: NCT02460042). The primary end point was the 12-month target lesion revascularization (TLR) rate. Secondary end points included vessel patency, target vessel revascularization, and all-cause mortality. A total of 879 lesions in 784 consecutive patients (71.3 ± 10.4 years old, 57.7% male) were analyzed; 53.3% had claudication, whereas the remaining 46.7% exhibited critical limb ischemia (CLI). Substantial comorbidities were present, including diabetes mellitus (41.2%), smoking (66.1%), and coronary artery disease (33.9%). Lesion length (879 lesions) was 12.0 ± 9.3 cm and 31.8% were Transatlantic Inter-Society Consensus II C/D lesions. The overall technical success rate of the 1269 drug-coated balloon (DCB)'s used was 99.6% (1.60 ± 0.79 DCB's/patient). At 12 months, the TLR rates were 6.3% in patients with CLI and 9.6% in claudicants, with a primary patency rate of 89.9% and 87.1%, respectively. All-cause mortality was 4.3% (28/658). The most important predictors for TLR were female gender, in-stent restenosis at baseline and lesion length.


Assuntos
Angioplastia com Balão/mortalidade , Artéria Femoral , Doença Arterial Periférica/terapia , Artéria Poplítea , Idoso , Idoso de 80 Anos ou mais , Angioplastia com Balão/efeitos adversos , Angioplastia com Balão/instrumentação , Fármacos Cardiovasculares/administração & dosagem , Causas de Morte , Materiais Revestidos Biocompatíveis , Europa (Continente) , Feminino , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/fisiopatologia , Humanos , Malásia , Masculino , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/mortalidade , Doença Arterial Periférica/fisiopatologia , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/fisiopatologia , Estudos Prospectivos , Recidiva , Resveratrol/administração & dosagem , Medição de Risco , Fatores de Risco , Fatores Sexuais , Fatores de Tempo , Resultado do Tratamento , Dispositivos de Acesso Vascular , Grau de Desobstrução Vascular
5.
Sensors (Basel) ; 17(7)2017 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-28708080

RESUMO

In grapevine research the acquisition of phenotypic data is largely restricted to the field due to its perennial nature and size. The methodologies used to assess morphological traits and phenology are mainly limited to visual scoring. Some measurements for biotic and abiotic stress, as well as for quality assessments, are done by invasive measures. The new evolving sensor technologies provide the opportunity to perform non-destructive evaluations of phenotypic traits using different field phenotyping platforms. One of the biggest technical challenges for field phenotyping of grapevines are the varying light conditions and the background. In the present study the Phenoliner is presented, which represents a novel type of a robust field phenotyping platform. The vehicle is based on a grape harvester following the concept of a moveable tunnel. The tunnel it is equipped with different sensor systems (RGB and NIR camera system, hyperspectral camera, RTK-GPS, orientation sensor) and an artificial broadband light source. It is independent from external light conditions and in combination with artificial background, the Phenoliner enables standardised acquisition of high-quality, geo-referenced sensor data.


Assuntos
Vitis , Fenótipo
6.
Rofo ; 189(4): 309-311, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28335057

RESUMO

Purpose Scope and clinical importance of interventional radiology markedly evolved over the last decades. Consequently it was acknowledged as independent subspecialty by the "European Union of Medical Specialists" (UEMS). Based on radiological imaging techniques Interventional Radiology is an integral part of Radiology. Materials und Methods In 2009 the German Society for Interventional Radiology and minimally-invasive therapy (DeGIR) developed a structured training in Interventional Radiology. In cooperation with the German Society of Neuroradiology (DGNR) this training was extended to also cover Interventional Neuroradiology in 2012. Tailored for this training in Interventional Radiology a structured curriculum was developed, covering the scope of this modular training. Results The curriculum is based on the DeGIR/DGNR modular training concept in Interventional Radiology. There is also an European Curriculum and Syllabus for Interventional Radiology developed by the "Cardiovascular and Interventional Radiological Society of Europe" (CIRSE). The presented curriculum in Interventional Radiology is designed to provide a uniform base for the training in Interventional Radiology in Germany, based on the competencies obtained during residency. Conclusion This curriculum can be used as a basis for training in Interventional Radiology by all training sites. Key Points: · Interventional Radiology is an integral part of clinical radiology. · The German Society for Interventional Radiology and minimally-invasive therapy (DeGIR) developed a curriculum in Interventional Radiology. · This curriculum is an integrative basis for the training in interventional. Citation Format · Mahnken AH, Bücker A, Hohl C et al. White Paper: Curriculum in Interventional Radiology. Fortschr Röntgenstr 2017; 189: 309 - 311.


Assuntos
Currículo/normas , Guias como Assunto , Radiografia Intervencionista/normas , Radiologia Intervencionista/educação , Radiologia Intervencionista/normas , Alemanha
7.
Invest Radiol ; 48(4): 231-7, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23385397

RESUMO

PURPOSE: The aim of this study was to investigate if 3.0-T diffusion-weighted magnetic resonance imaging (MRI) can be used for early detection of acute occlusive and nonocclusive mesenteric ischemia. MATERIALS AND METHODS: In this study, approved by the official committee on animal affairs, proximal (occlusive) mesenteric ischemia and peripheral (nonocclusive) mesenteric ischemia were induced in 8 and 2, respectively, female domestic pigs. Proximal mesenteric ischemia was induced by intra-arterial injection of n-butyl-cyanoacrylate in the superior mesenteric artery or 1 of its main branches; peripheral mesenteric ischemia was induced by intra-arterial injection of microparticles. Before embolization and at 30-, 60-, and 90-minute intervals after embolization, diffusion-weighted imaging was performed, and apparent diffusion coefficient (ADC) maps were calculated on a clinical 3.0-T system. Immediately after the last MRI session, animals were killed to provide a pathological correlation for mesenteric ischemia. RESULTS: Ischemic bowel parts appeared hyperintense on diffusion-weighted images and hypointense on the corresponding ADC maps. Mean diffusion-weighted imaging signal intensity increased and ADC decreased significantly within 30 minutes after embolization (P < 0.001) and remained unchanged until 90 minutes after injury, independent of the embolization method. CONCLUSIONS: 3.0-Tesla diffusion-weighted MRI may help detect acute mesenteric ischemia as early as 30 minutes after vessel occlusion.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Isquemia/diagnóstico , Doenças Vasculares/diagnóstico , Animais , Embolização Terapêutica , Feminino , Isquemia/terapia , Isquemia Mesentérica , Estudos Prospectivos , Suínos , Doenças Vasculares/terapia
8.
BMC Surg ; 10: 5, 2010 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-20113514

RESUMO

BACKGROUND: Traumatic diaphragmatic ruptures affect mainly the left side. In an experimental study in human corpses we examined the stretch behaviour of the left and right diaphragmatic halves. METHODS: In a total of 8 male and 8 female corpses each diaphragmatic half was divided into 4 different segments. Each segments stretch behaviour was investigated. In steps of 2 N the stretch was increased up to 24 N. RESULTS: In the female the left diaphragm showed a stronger elasticity compared to the right. Additionally the left diaphragm in females showed a higher elasticity in comparison to the left in males. Traumatic diaphragmatic ruptures affect mostly the central tendineous part or the junction between tendineous and muscular part of the diaphragmatic muscle. Accordingly we found a lower elasticity in these parts compared with the other diaphragmatic segments. CONCLUSION: In summary it can be said that albeit some restrictions we were able to determine the elasticity of different diaphragmatic segments quantitatively and reproduceably with our presented method. Thereby a comparison of results of different diaphragmatic segments as well as of both diaphragmatic halves and of both genders was possible.


Assuntos
Diafragma/lesões , Diafragma/fisiologia , Elasticidade , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Invest Radiol ; 43(7): 530-7, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18580336

RESUMO

OBJECTIVES: To assess the feasibility of magnetic resonance (MR)-guided delivery of a solution containing contrast-medium and immediate online monitoring of its distribution to the vessel wall during MR-guided angioplasty in peripheral arteries. MATERIALS AND METHODS: In 3 pigs, the feasibility of MR-guided atraumatic delivery of a solution containing contrast-medium and tissue dye (0.05 mmol/mL Gd-DTPA, 3% Evans blue dye) into the vessel wall of the iliac arteries was tested using a permeable balloon catheter (8 mm). Catheter placement was monitored using a steady-state free precession real-time imaging sequence.Additionally, in 5 pigs, surgically created bilateral stenoses in the external iliac artery were dilatated with the porous balloon. In these animals, contrast-enhanced MR angiography was performed before and after the interventions to assess the degree of the stenosis. In all animals, the vessel wall was delineated before and after dilatation using a T1-weighted gradient echo (GE) sequence. RESULTS: In the 3 animals without stenosis, contrast medium was successfully applied to the vessel wall. On the GE images, the normalized signal intensity of the vessel wall was 0.95 +/- 0.015 arbitrary units (a. u.) prior and 2.15 +/- 0.105 a. u. after the intervention (P < 0.01). In the animals with stenosis, MR angiography performed before and after the intervention demonstrated successful dilatation of 9 of the 10 stenoses. Before the intervention, 7 stenoses were severe (76%-99%) and 3 moderate (50%-75%), and after the intervention, 4 stenoses were completely removed and 5 mild (<50%). Also in these 5 animals, the solution was visible in the vessel wall of the arteries on the T1-weighted GE MR images (normalized signal intensity prior the intervention 1.33 +/- 0.16 a. u. and 2.97 +/- 0.23 after angioplasty; P < 0.05). Histology demonstrated the distribution of the Evan's blue dye within the vessel wall in all animals. CONCLUSIONS: MR-guided delivery of a contrast-medium containing solution and immediate online assessment of its distribution to the vessel wall during angioplasty in peripheral arteries is feasible.


Assuntos
Angioplastia/métodos , Gadolínio DTPA/administração & dosagem , Artéria Ilíaca/anatomia & histologia , Artéria Ilíaca/cirurgia , Imagem por Ressonância Magnética Intervencionista/métodos , Cirurgia Assistida por Computador/métodos , Animais , Meios de Contraste/administração & dosagem , Estudos de Viabilidade , Aumento da Imagem/métodos , Suínos , Resultado do Tratamento
10.
AJR Am J Roentgenol ; 190(2): 467-73, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18212234

RESUMO

OBJECTIVE: The purposes of this study were to evaluate prospective adjustment of dose settings in pediatric 16-MDCT by use of computer-simulated images in a patient image gallery and to compare the dose reduction achieved with that of standard pediatric protocols. SUBJECTS AND METHODS: The image gallery consisted of images from weight-dependent sample examinations performed with varied simulated tube current-exposure time settings. The scanning parameters prospectively chosen on the basis of the image quality of the image gallery were used for 30 16-MDCT examinations (chest, n = 15; abdomen, n = 8; pelvis, n = 7) of 22 children (14 boys, eight girls; mean age, 6.8 +/- 5.8 years; mean body weight, 26.7 +/- 19.6 kg). Three blinded radiologists used a 4-point grading scale to rate the overall image quality of the image gallery and the 16-MDCT scans. Objective and subjective image quality was assessed for the simulated and actual CT scans. The concordance correlation coefficient (K) was determined. RESULTS: There was mainly moderate concordance with regard to objective (chest, K = 0.69; abdomen, K = 0.33; pelvis, K = 0.55) and subjective (chest soft-tissue window, kappa coefficient [kappa] = 0.00; chest lung window, kappa = 0.53; abdomen, kappa = 1.00; pelvis, kappa = 0.48) analysis of image gallery compared with actual 16-MDCT examinations. Compared with use of previous weight-adapted pediatric standard protocols, use of an image gallery resulted in further dose reduction for abdominal and pelvic CT but not for thoracic CT. CONCLUSION: A patient image gallery can be used as a basis for pediatric 16-MDCT examinations. The gallery provides a preexamination overview of expected image quality. Radiation exposure can be optimized with regard to patient weight and the image quality needed to answer the clinical question.


Assuntos
Doses de Radiação , Lesões por Radiação/prevenção & controle , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Criança , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Método Simples-Cego
11.
Radiology ; 246(2): 519-25, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18227544

RESUMO

PURPOSE: To prospectively evaluate, in a phantom, the dose reductions achievable by using angular beam modulation (ABM) during computed tomographic (CT) fluoroscopy-guided thoracic interventions. MATERIALS AND METHODS: To enable measurement of organ doses and effective patient dose, a female Alderson-Rando phantom was equipped with thermoluminescent dosimeters (TLDs) in 41 positions, with three TLDs in each position. Additionally, the local dose was assessed in 22 locations above the phantom to estimate the radiation exposure to the radiologist's hand and the patient's skin dose during thoracic interventions. Radiation exposure was performed with a 64-section multidetector CT scanner in the CT fluoroscopy mode, simulating a CT fluoroscopy-guided chest intervention. Effective dose, breast dose, and the dose to the radiologist's hand during the simulated chest intervention were measured with and without ABM. Image noise as an indicator for image quality was compared for both settings. Statistical significance of the measured dose reductions and the image noise was tested by using the paired-samples t test, with P < .05 indicating a significant difference. RESULTS: ABM significantly reduced the effective patient dose by 35%, the skin dose by 75%, the breast dose by 47% (P < .001 for all), and the physician's hand dose by between 27% (scattered radiation, P = .007) and 72% (direct radiation, P < .001). No significant difference was found in a comparison of the image noise with and that without ABM. CONCLUSION: ABM leads to significant dose reductions for both patients and personnel during CT fluoroscopy-guided thoracic interventions, without impairing image quality.


Assuntos
Carga Corporal (Radioterapia) , Fluoroscopia/métodos , Aumento da Imagem/métodos , Radiografia Intervencionista/métodos , Radiografia Torácica/métodos , Radiometria/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Feminino , Fluoroscopia/instrumentação , Humanos , Imagens de Fantasmas , Doses de Radiação , Radiografia Intervencionista/instrumentação , Radiografia Torácica/instrumentação , Eficiência Biológica Relativa , Tomografia Computadorizada por Raios X/instrumentação
12.
Invest Radiol ; 42(11): 756-64, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18030198

RESUMO

OBJECTIVE: We sought to evaluate the ability of retrospectively ECG-gated dual-source computed tomography (DSCT) to assess left (LV) and right ventricular (RV) functional parameters in comparison to 1.5 T magnetic resonance imaging (MRI). MATERIALS AND METHODS: Ten domestic pigs (60 kg) underwent both contrast-enhanced cardiac DSCT and cardiac MRI using standardized examination protocols under general anesthesia. From manually drawn endocardial and epicardial contours, LV and RV end-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), peak filling rate (PFR), peak ejection rate (PER), time to peak ejection (TPE), and time to peak filling (TPF) were calculated by means of dedicated analysis software. LV and RV functional parameters were analyzed using Bland-Altman plots, Student t test, and Pearson's correlation coefficient. RESULTS: Both left and right ESV and EDV, SV and EF determined with DSCT correlated well with MR imaging results (left, r = 0.98/0.92/0.82/0.98; right, r = 0.90/0.94/0.96/0.94). PER, PFR, TPE, TPF, and MM showed only a moderate to low correlation (left, r = 0.67/0.37/0.23/0.35/0.57; right, r = 0.78/0.69/0.12/0.11/0.44). PER and PFR were significantly underestimated by DSCT when compared with MRI. CONCLUSIONS: Retrospectively ECG-gated DSCT correctly depicts end-systole and can accurately determine LV and RV volumes, SV, and EF in comparison to MRI. DSCT showed a significant underestimation of PER and PFR in comparison to MRI.


Assuntos
Ventrículos do Coração/anatomia & histologia , Ventrículos do Coração/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Modelos Animais , Tomografia Computadorizada por Raios X/métodos , Função Ventricular Esquerda/fisiologia , Função Ventricular Direita/fisiologia , Animais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Suínos
13.
Invest Radiol ; 42(7): 491-8, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17568271

RESUMO

PURPOSE: To investigate the influence of heart rate and temporal resolution on the assessment of global ventricular function with dual-source computed tomography (DSCT). MATERIALS AND METHODS: A dynamic cardiac phantom was repeatedly scanned with a DSCT scanner applying a standardized scan protocol at different heart rates, ranging from 40 to 140 bpm. Images were reconstructed with monosegmental and bisegmental algorithms using data from a single source and from both sources. Ventricular volumes and ejection fraction (EF) were computed by semiautomated analysis. Results were compared with the phantom's real volumes. Interscan, intraobserver, and interobserver variability were calculated. RESULTS: For single-source data reconstruction temporal resolution was fixed to 165 milliseconds, whereas dual-source image reconstructions resulted in a temporal resolution of 83 milliseconds (monosegmental) and 67.7+/-14.2 milliseconds (bisegmental), respectively. In general, deviation from the phantom's real volumes was less with dual-source data reconstruction when compared with single-source data reconstruction. Comparing dual-source data reconstruction with single-source data reconstruction, the percent deviation from the phantom's real volumes for EF was 0.7% (monosegmental), 0.7% (bisegmental), and 4.3% (single source), respectively. There was no correlation between heart rate and EF for dual-source data reconstruction (r=-0.168; r=-0.157), whereas a relevant correlation was observed for single-source data reconstruction (r=-0.844). Interscan, intraobserver, and interobserver variability for EF were 1.4%, 0.9%, and 0.3%, respectively. CONCLUSIONS: DSCT allows reliable quantification of global ventricular function independent of the heart rate. Multisegmental image reconstruction is not needed for DSCT assessment of global ventricular function.


Assuntos
Coração/fisiologia , Processamento de Imagem Assistida por Computador/instrumentação , Imagens de Fantasmas , Volume Sistólico , Tomografia Computadorizada por Raios X/instrumentação , Função Ventricular , Algoritmos , Frequência Cardíaca , Ventrículos do Coração/patologia , Humanos , Projetos Piloto
14.
Eur Radiol ; 17(7): 1850-7, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17308926

RESUMO

The aim of our study was to evaluate attenuation-based tube current adaptation in coronary calcium scoring using ECG-gated multi-detector-row CT (MDCT). A total of 262 patients underwent non-enhanced cardiac MDCT. Group 1 was scanned using a standard protocol with 120 kV and 150 mAs(eff). Groups 2-4 were scanned using an attenuation-based dose-adaptation template (CARE Dose) with different effective reference mAs settings (150, 180, 210 mAs(eff)). Body-mass index (BMI) and CT-dose index values were calculated for each patient. Image noise and subjective image quality were assessed. Regression analysis was performed, and the variation coefficient of image noise was determined. Compared to the standard scan protocol a dose reduction of 31.1% for group 2 and 20.1% for group 3 was observed. Measurement variation of image noise was smaller for the attenuation-based dose adaptation protocols (group 2-4) (16.2-17.1%) compared to the standard scan protocol (32.3%). Regression analysis of groups 2-4 showed better correlation with improved dose usage based on BMI (all P

Assuntos
Calcinose/diagnóstico por imagem , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Eletrocardiografia , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada Espiral/métodos , Idoso , Artefatos , Índice de Massa Corporal , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Sensibilidade e Especificidade
15.
AJR Am J Roentgenol ; 188(2): 361-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17242243

RESUMO

OBJECTIVE: The objective of our study was to determine the accuracy of 16-MDCT for evaluation of stent patency and in-stent stenosis in venous coronary bypass grafts. SUBJECTS AND METHODS: Fourteen patients who had previous stent placements in stenosed venous coronary bypass grafts underwent contrast-enhanced MDCT of the heart (collimation, 16 x 0.75 mm; 120 kV; 550 mAs(eff)) and invasive coronary angiography. A total of 20 stents were evaluated: Vessel and stent diameters proximal to, distal to, and at various sites inside the stent were measured on both techniques, and Bland-Altman plots and correlations were calculated. Image noise and image quality were also assessed applying a Student's t test for data comparison of image noise. RESULTS: All 20 bypass stents were correctly classified as patent. Vessel diameters outside the stent showed an excellent correlation (r = 0.90) and in-stent diameters showed a good correlation (r = 0.72), with lower values for MDCT due to blooming artifacts. All significant in-stent stenoses were correctly classified. CONCLUSION: In patients suspected of bypass in-stent stenosis, 16-MDCT may be considered as a valuable alternative to conventional angiography for evaluating bypass patency and in-stent stenosis.


Assuntos
Prótese Vascular/efeitos adversos , Ponte de Artéria Coronária/efeitos adversos , Ponte de Artéria Coronária/instrumentação , Oclusão de Enxerto Vascular/diagnóstico por imagem , Oclusão de Enxerto Vascular/etiologia , Stents/efeitos adversos , Tomografia Computadorizada por Raios X/métodos , Cateterismo Cardíaco , Angiografia Coronária , Ponte de Artéria Coronária/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Implantação de Prótese/efeitos adversos , Implantação de Prótese/métodos , Tomografia Computadorizada por Raios X/instrumentação , Resultado do Tratamento
16.
Invest Radiol ; 42(2): 123-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17220730

RESUMO

OBJECTIVE: We sought to evaluate the influence of tube voltage on the visualization of acute myocardial infarction (MI) in cardiac multislice spiral computed tomography (MSCT). MATERIALS AND METHODS: Acute MI was induced in 12 domestic pigs by a 45-minute balloon occlusion of the left anterior descending artery. Delayed enhancement magnetic resonance imaging was performed 15 minutes after the injection of 0.2 mmol/kg Gd-DTPA. On the same day, retrospectively ECG-gated MSCT was performed at 120, 100, and 80 kV (16x0.75mm, 550mAseff.) 15 minutes after the injection of 140 mL of iopromide (1 g/iodine/kg). The pigs were killed and the hearts were excised and stained with 2,3,5-triphenyltetrazolium chloride. The area of acute MI, contrast-to-noise ratio (CNR), and percent signal difference were compared among the different imaging techniques by applying Bland-Altman plots and 2-way analysis of variance. RESULTS: On MSCT at 120, 100, and 80 kV, the respective mean acute MI sizes were 18.4+/-11.4%, 19.3+/-11.5%, and 20.5+/-11.6%. The mean MI sizes were 20.8+/-12.2% and 20.1+/-12.4% on magnetic resonance imaging and 2,3,5-triphenyltetrazolium chloride staining. Analysis of variance did not show any statistically significant differences between the different techniques with respect to the size of acute MI (P=0.9880). Comparing the different kV settings on MSCT, the highest percent signal difference (74.7+/-12.1%) and the highest CNR (6.7+/-1.8) between infarcted and healthy remote myocardium were achieved at 80 kV. CONCLUSIONS: When compared with routine scan protocols, low tube voltage MSCT allows for the assessment of the MI size with an improved CNR and contrast resolution. This technique appears to be advantageous for assessing myocardial viability from contrast enhanced late-phase MSCT.


Assuntos
Modelos Animais de Doenças , Iohexol/análogos & derivados , Infarto do Miocárdio/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Meios de Contraste/administração & dosagem , Iohexol/administração & dosagem , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Suínos
17.
Eur Radiol ; 17(2): 321-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16819606

RESUMO

The accuracy of coronary calcium scoring using 16-row MSCT comparing 1- and 3-mm slices was assessed. A thorax phantom with calcium cylinder inserts was scanned applying a non-enhanced retrospectively ECG-gated examination protocol: collimation 12 x 0.75 mm; 120 kV; 133 mAs(eff). Thirty-eight patients were examined using the same scan protocol. Image reconstruction was performed with an effective slice thickness of 3 and 1 mm. The volume score, calcium mass and Agatston score were determined. Image noise was measured in both studies. The volume score and calcium mass varied less than the Agatston score. The overall measured calcium mass compared to the actual calcium mass revealed a relative difference of +2.0% for 1-mm slices and -1.2% for 3-mm slices. Due to increased image noise in thinner slices in the patient study (26.1 HU), overall calcium scoring with a scoring threshold of 130 HU was not feasible. Interlesion comparison showed significantly higher scoring results for thinner slices (all P<0.001). A similar accuracy comparing calcium scoring results of 1- and 3-mm slices was shown in the phantom study; therefore, the potentially necessary increase of the patient's dose in order to achieve assessable 1-mm slices with an acceptable image-to-noise-ratio appears not to be justified.


Assuntos
Calcinose/diagnóstico por imagem , Doença da Artéria Coronariana/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Idoso , Calcinose/patologia , Doença da Artéria Coronariana/patologia , Feminino , Alemanha , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/classificação
18.
Invest Radiol ; 41(9): 668-73, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16896301

RESUMO

OBJECTIVES: We sought to compare an 80-kVp coronary calcium scoring protocol with the standard protocol of 120 kVp in terms of accuracy and reproducibility and to assess its dose reduction potential. MATERIALS AND METHOD: An anthropomorphic heart phantom with calcium cylinders was scanned with different tube currents at 80 kVp and 120 kVp using a 16-slice multislice CT (MSCT) scanner. An adapted threshold for 80 kVp was calculated. Accuracy and reproducibility for calcium mass, volume, and Agatston score were analyzed using F-tests. The radiation doses needed to produce artifact-free images were determined. RESULTS: Accuracy (measurement errors: mass 120 kVp +4.6%, mass 80 kVp -6.9%, volume 120 kVp +78.8%, volume 80 kVp +58.2%) and reproducibility (F-tests: mass: P = 0.4998, volume: P = 0.9168, Agatston: P = 0.5422) were comparable at both tube voltages. Avoiding the appearance of artificial lesions, a CTDI(w,eff) of 10.7 mGy was needed at 120 kVp versus 4.6 mGy at 80 kVp (dose reduction of 57%). CONCLUSIONS: Using an 80-kVp protocol in coronary calcium scoring, a relevant dose reduction is possible without compromising reproducibility and accuracy.


Assuntos
Calcinose/diagnóstico por imagem , Cálcio/análise , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/normas , Análise de Variância , Calibragem , Imagens de Fantasmas , Curva ROC , Reprodutibilidade dos Testes , Tomógrafos Computadorizados
19.
Eur Radiol ; 16(8): 1684-91, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16622687

RESUMO

PURPOSE: To evaluate the value of dose-reduced 16-slice multidetector-row spiral computed tomography (16-MDCT) using virtual tracheobronchoscopy (VTB) and virtual bronchography (VBG) in children with suspected tracheobronchial stenosis. MATERIALS AND METHODS: 12 children (4 d to 3 years, body weight 1.2 kg to 13.5 kg) with stridor and suspected tracheobronchial stenosis were examined by contrast-enhanced low-dose 16-MDCT. Conventional axial slices, MPRs, VTB, and VBG were calculated. Image findings were correlated with the results of fiberoptic bronchoscopy (12 out of 12) as a gold standard and subsequent surgery (8 out of 12). RESULTS: VTB and VBG demonstrated the fiberoptic bronchoscopically suspected tracheal stenosis in 11 of 12 children due to vascular compression because of the brachiocephalic trunk (6), a double aortic arch (2), a vascular compression of the left main bronchus (2), and a right aberrant subclavian artery (1). Eleven out of 12 stenoses were correctly depicted by conventional axial slices, MPRs, VTB, and VBG. Dose reduction was 79 to 85.8% compared to a standard adult chest CT. CONCLUSION: Dose-reduced 16-MDCT with the use of VTB and VBG is effective for the evaluation of tracheobronchial stenosis in children and correlates well with fiberoptic bronchoscopy.


Assuntos
Obstrução das Vias Respiratórias/diagnóstico por imagem , Broncopatias/diagnóstico por imagem , Broncografia/métodos , Broncoscopia , Tomografia Computadorizada Espiral , Estenose Traqueal/diagnóstico por imagem , Interface Usuário-Computador , Artefatos , Pré-Escolar , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Lactente , Recém-Nascido , Masculino , Radiometria/métodos
20.
Invest Radiol ; 41(5): 429-35, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16625105

RESUMO

PURPOSE: We sought to investigate the influence of heart rate and temporal resolution on the assessment of left-ventricular (LV) function with multislice spiral computed tomography (CT). MATERIAL AND METHODS: A dynamic cardiac phantom was repeatedly scanned with a 64-slice CT scanner using a standardized scan protocol (64 x 0.6 mm, 120kV, 770mAs(eff), 330 milliseconds rotation time) at different simulated heart rates, ranging from 40 to 140 beats per minute. Images were reconstructed with an algorithm utilizing data from 1 to 4 cardiac cycles (RR intervals). Ejection fraction (EF), end-systolic, end-diastolic, and stroke volume as well as cardiac output were calculated. Results of the measurements were compared with the real volumes of the phantom. Interscan and intraobserver variability were calculated. RESULTS: Using a monosegmental reconstruction algorithm, the temporal resolution was fixed to 165 milliseconds. With bi-, tri-, and quad-segmental image reconstruction, mean temporal resolution was 128.3 +/- 33.2 milliseconds, 103.3 +/- 49.2 milliseconds, and 87.8 +/- 81.5 milliseconds, respectively. Multisegmental image reconstruction resulted in a lower deviation when comparing measured and real volumes. Using mono-, bi-, tri-, and quad-segmental image reconstruction, the percent deviation between measured and real values for EF was 8.2%, 4.5%, 3.3%, and 3.4%, respectively. Applying multisegmental image reconstruction with improved temporal resolution the deviation decreased with increasing heart rate when compared with mono-segmental image reconstruction. Interscan and intraobserver variability for EF were 1.1% and 1.9%, respectively. CONCLUSION: Enhanced temporal resolution improves the quantification of LV volumes in cardiac multislice spiral CT, enabling reliable assessment of LV volumes even at increased heart rates.


Assuntos
Frequência Cardíaca/fisiologia , Imagens de Fantasmas , Volume Sistólico/fisiologia , Tomografia Computadorizada Espiral/instrumentação , Função Ventricular Esquerda/fisiologia , Algoritmos , Volume Cardíaco/fisiologia , Humanos , Interpretação de Imagem Radiográfica Assistida por Computador
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...