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1.
Invest Radiol ; 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32028297

RESUMO

OBJECTIVES: The aim of this study was to improve the visualization of coagulation necrosis after computed tomography (CT)-guided microwave ablation (MWA) in routine postablational imaging. MATERIALS AND METHODS: Ten MWAs were performed in 8 pigs under CT guidance. After each ablation, we obtained contrast-enhanced CT scans in venous phase. Ablations were then resected as a whole, and histologic slices were obtained orthogonally through the ablation center. Subsequently, a vital stain was applied to the sections for visualization of coagulation necrosis. Computed tomography images were reformatted to match the histologic slices. Afterwards, quantitative imaging features were extracted from the subregions of all images, and binary classifiers were used to predict the presence of coagulation necrosis for each subregion. From this, heatmaps could be created, which visually represented the extent of necrosis in each CT image. Two independent observers evaluated the extent of coagulative necrosis between the heat maps and histological sections. RESULTS: We applied 4 different classifiers, including a generalized linear mixed model (GLMM), a stochastic gradient boosting classifier, a random forest classifier, and a k-nearest neighbor classifier, out of which the GLMM showed the best performance to display coagulation necrosis. The GLMM resulted in an area under the curve of 0.84 and a Jaccard index of 0.6 between the generated heat map and the histologic reference standard as well as a good interobserver agreement with a Jaccard index of 0.9. CONCLUSIONS: Subregion radiomics analysis may improve visualization of coagulation necrosis after hepatic MWA in an in vivo porcine model.

2.
Sci Rep ; 10(1): 805, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31965024

RESUMO

Microwave ablation (MWA) is a type of minimally invasive cancer therapy that uses heat to induce necrosis in solid tumours. Inter- and post-ablational size changes can influence the accuracy of control imaging, posing a risk of incomplete ablation. The present study aims to explore post-ablation 3D size dynamics in vivo using computed tomography (CT). Ten MWA datasets obtained in nine healthy pigs were used. Lesions were subdivided along the z-axis with an additional planar subdivision into eight subsections. The volume of the subsections was analysed over different time points, subsequently colour-coded and three-dimensionally visualized. A locally weighted polynomial regression model (LOESS) was applied to describe overall size changes, and Student's t-tests were used to assess statistical significance of size changes. The 3D analysis showed heterogeneous volume changes with multiple small changes at the lesion margins over all time points. The changes were pronounced at the upper and lower lesion edges and characterized by initially eccentric, opposite swelling, followed by shrinkage. In the middle parts of the lesion, we observed less dimensional variations over the different time points. LOESS revealed a hyperbolic pattern for the volumetric changes with an initially significant volume increase of 11.6% (111.6% of the original volume) over the first 32 minutes, followed by a continuous decrease to 96% of the original volume (p < 0.05).

3.
Sci Rep ; 9(1): 18506, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811190

RESUMO

After hepatic microwave ablation, the differentiation between fully necrotic and persistent vital tissue through contrast enhanced CT remains a clinical challenge. Therefore, there is a need to evaluate new imaging modalities, such as CT perfusion (CTP) to improve the visualization of coagulation necrosis. MWA and CTP were prospectively performed in five healthy pigs. After the procedure, the pigs were euthanized, and the livers explanted. Orthogonal histological slices of the ablations were stained with a vital stain, digitalized and the necrotic core was segmented. CTP maps were calculated using a dual-input deconvolution algorithm. The segmented necrotic zones were overlaid on the DICOM images to calculate the accuracy of depiction by CECT/CTP compared to the histological reference standard. A receiver operating characteristic analysis was performed to determine the agreement/true positive rate and disagreement/false discovery rate between CECT/CTP and histology. Standard CECT showed a true positive rate of 81% and a false discovery rate of 52% for display of the coagulation necrosis. Using CTP, delineation of the coagulation necrosis could be improved significantly through the display of hepatic blood volume and hepatic arterial blood flow (p < 0.001). The ratios of true positive rate/false discovery rate were 89%/25% and 90%/50% respectively. Other parameter maps showed an inferior performance compared to CECT.

4.
Int J Hyperthermia ; 36(1): 1098-1107, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31724443

RESUMO

Background: Accurate lesion visualization after microwave ablation (MWA) remains a challenge. Computed tomography perfusion (CTP) has been proposed to improve visualization, but it was shown that different perfusion-models delivered different results on the same data set.Purpose: Comparison of different perfusion algorithms and identification of the algorithm enables for the best imaging of lesion after hepatic MWA.Materials and methods: 10 MWA with consecutive CTP were performed in healthy pigs. Parameter-maps were generated using a single-input-dual-compartment-model with Patlak's algorithm (PM), a dual-input-maximum-slope-model (DIMS), a dual-input-one-compartment-model (DIOC), a single-(SIDC) and dual-input-deconvolution-model (DIDC). Parameter-maps for hepatic arterial (AF) and portal venous blood flow (PF), mean transit time, hepatic blood volume (HBV) and capillary permeability were compared regarding the values of the normal liver tissue (NLT), lesion, contrast- and signal-to-noise ratios (SNR, CNR) and inter- and intrarater-reliability using the intraclass correlation coefficient, Bland-Altman plots and linear regression.Results: Perfusion values differed between algorithms with especially large fluctuations for the DIOC. A reliable differentiation of lesion margin appears feasible with parameter-maps of PF and HBV for most algorithms, except for the DIOC due to large fluctuations in PF. All algorithms allowed for a demarcation of the central necrotic zone based on hepatic AF and HBV. The DIDC showed the highest CNR and the best inter- and intrarater reliability.Conclusion: The DIDC appears to be the most feasible model to visualize margins and necrosis zones after microwave ablation, but due to high computational demand, a single input deconvolution algorithm might be preferable in clinical practice.

6.
Clin Hemorheol Microcirc ; 73(2): 371-378, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31156148

RESUMO

BACKGROUND: Animal liver is established as an ex vivo model for studies on hepatic microwave ablation (MWA). Macroscopically visible color changes in the ablation zone are used to assess cell destruction and confirm successful ablation ex vivo. OBJECTIVE: Macroscopy and histology of MWA zones regarding cell viability in ex vivo porcine livers were compared in this study. METHODS: Six MWA were performed in porcine livers post mortem. A 14-G antenna and microwave generator (928 MHz; 9.0 kJ) were used. MWA were cut at the maximum cross section in vertical alignment to the antenna. NADH-diaphorase staining determined cell vitality. Macroscopic and microscopic ablation zones were statistically analyzed. RESULTS: Histology showed two distinct ablation zones: central white zone (WZH) with no cell viability and peripheral red zone (RZH) with partial cell viability. However, the macroscopically visible WZM was significantly smaller than the microscopic WZH with an area difference of 43.1% (p < 0.05) and a radius difference of 21.2% (1.6 mm; p < 0.05). Macroscopy and histology showed a very high correlation for the complete lesion area (WZH/M+RZH/M; r = 0.9; p = 0.001). CONCLUSIONS: The avital central zone is significantly larger as the macroscopically visible WZ which is commonly used to assess successful ablation in MWA ex vivo studies. Irreversible cell destruction can be underestimated in macroscopic evaluation.

7.
PLoS One ; 14(4): e0215875, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31022244

RESUMO

Over many decades, the Göttingen Minipig has been used as a large animal model in experimental surgical research of the mandible. Recently several authors have raised concerns over the use of the Göttingen Minipig in this research area, observing problems with post-operative wound healing and loosening implants. To reduce these complications during and after surgery and to improve animal welfare in mandibular surgery research, the present study elucidated how comparable the mandible of minipigs is to that of humans and whether these complications could be caused by specific anatomical characteristics of the minipigs' mandible, its masticatory muscles and associated vasculature. Twenty-two mandibular cephalometric parameters were measured on CT scans of Göttingen Minipigs aged between 12 and 21 months. Ultimately, we compared this data with human data reported in the scientific literature. In addition, image segmentation was used to determine the masticatory muscle morphology and the configuration of the mandibular blood vessels. Compared to data of humans, significant differences in the mandibular anatomy of minipigs were found. Of the 22 parameters measured only four were found to be highly comparable, whilst the others were not. The 3D examinations of the minipigs vasculature showed a very prominent deep facial vein directly medial to the mandibular ramus and potentially interfering with the sectional plane of mandibular distraction osteogenesis. Damage to this vessel could result in inaccessible bleeding. The findings of this study suggest that Göttingen Minipigs are not ideal animal models for experimental mandibular surgery research. Nevertheless if these minipigs are used the authors recommend that radiographic techniques, such as computed tomography, be used in the specific planning procedures for the mandibular surgical experiments. In addition, it is advisable to choose suitable age groups and customize implants based on the mandibular dimensions reported in this study.


Assuntos
Anatomia Comparada , Cefalometria , Mandíbula/anatomia & histologia , Mandíbula/cirurgia , Músculos da Mastigação/anatomia & histologia , Músculos da Mastigação/irrigação sanguínea , Porco Miniatura/crescimento & desenvolvimento , Adulto , Pontos de Referência Anatômicos , Animais , Vasos Sanguíneos/diagnóstico por imagem , Feminino , Humanos , Imagem Tridimensional , Mandíbula/irrigação sanguínea , Mandíbula/diagnóstico por imagem , Músculos da Mastigação/diagnóstico por imagem , Suínos
8.
Acta Radiol Open ; 8(4): 2058460119836256, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31007947

RESUMO

Background: Intramural duodenal hematoma is a rare condition. Different imaging modalities are at hand for diagnosis. Purpose: To identify patients with intramural duodenal hematoma and report imaging findings and clinical courses. Material and Methods: Typical imaging patterns using ultrasound, computed tomography, and magnetic resonance imaging were carried out on 10 patients. Results: The mean patient age was 7.5 years. The average disease duration was 13 months. Clinical signs of improvement were observed within 16 days. Residues were still detectable at long-term follow-up. Conclusion: For patients with intramural duodenal wall hematoma, diagnosis should be considered early. Typical imaging findings should be known to ensure optimal treatment.

9.
Invest Radiol ; 54(6): 333-339, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30652986

RESUMO

OBJECTIVES: The aim of this study was to investigate whether the accuracy of multislice contrast-enhanced computed tomography (MS-CECT) may be improved by performing additional subtraction CT. MATERIALS AND METHODS: Thirty-five microwave ablations were performed under CT guidance in 12 healthy and anesthetized pigs. Preablation and postablation MS-CECT scans were obtained in arterial and venous contrast phases. These scans were reconstructed and subtracted from each other. Lesion size was measured in a region of interest drawn around the ablation area. Computed tomography measurements were compared with standardized macroscopic images of explanted liver tissue, obtained immediately after ablation. Paired correlation and Bland-Altman analyses were performed for assessing agreement between modalities and ratings. RESULTS: The correlation between lesion size measured in CT and histology was very strong for subtracted images (r = 0.91; 95% confidence interval [CI], 0.8-0.96) and strong for standard MS-CECT images (r = 0.85; 95% CI, 0.68-0.93). Interrater agreement for all measurements was excellent (intraclass correlation coefficient, 0.99; 95% CI, 0.98-0.99 for subtraction and intraclass correlation coefficient, 0.99; 95% CI, 0.98-1.00 for MS-CECT). All differences were statistically significant (P < 0.05). CONCLUSIONS: Subtraction CT was superior to nonsubtracted MS-CECT in measurement of liver lesion size after microwave ablation in a porcine model, achieving a very strong correlation with pathologic measurement and a significantly lower overestimation of lesion size compared with MS-CECT.


Assuntos
Técnicas de Ablação/métodos , Processamento de Imagem Assistida por Computador/métodos , Fígado/diagnóstico por imagem , Fígado/cirurgia , Tomografia Computadorizada por Raios X/métodos , Animais , Feminino , Humanos , Masculino , Micro-Ondas , Modelos Animais , Reprodutibilidade dos Testes , Suínos
10.
Clin Res Cardiol ; 108(5): 465-467, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30259106

RESUMO

Late perforation of the atrial wall after pacemaker implantation frequently remains asymptomatic but may cause chest pain, dyspnea or syncope. Perforation can also lead to rarer complications such as hemoptysis and pneumopericardium. We present the case of a patient who developed progressive hemoptysis 3 years after a dual-chamber pacemaker implantation. Pacemaker interrogation showed stable impedance of the right atrial lead and stable pacing threshold values. CT revealed perforation of the right atrial wall by the RA-lead with consecutive pneumopericardium and diffuse lung bleeding of the right middle lobe. The patient was hemodynamically stable at all times. The right atrial lead was transvenously extracted and replaced without any further complications.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Remoção de Dispositivo/métodos , Átrios do Coração/lesões , Traumatismos Cardíacos/complicações , Hemoptise/etiologia , Marca-Passo Artificial/efeitos adversos , Pneumopericárdio/etiologia , Idoso de 80 Anos ou mais , Bloqueio Atrioventricular/terapia , Ecocardiografia , Feminino , Seguimentos , Átrios do Coração/diagnóstico por imagem , Traumatismos Cardíacos/diagnóstico , Traumatismos Cardíacos/cirurgia , Hemoptise/diagnóstico , Humanos , Pneumopericárdio/diagnóstico , Fatores de Tempo , Tomografia Computadorizada por Raios X
11.
Clin Hemorheol Microcirc ; 70(4): 467-476, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30347610

RESUMO

BACKGROUND: Radiofrequency ablation (RFA) is an important treatment option for hepatic tumors and metastases. Post-ablation recurrence rates are reported up to 36.5 percent and seem to depend on tumor size, intrahepatic localization of tumors and adjacent hepatic vessels. Multipolar RFA has the potential to overcome/reduce these limitations. Experimental and standardized data on achievable lesion sizes, influence of hepatic vessels and non-invasive evaluation of complete ablation is still insufficient. OBJECTIVES: The aim of this study was to evaluate the influence of intrahepatic vessels on shape and size of multipolar RF-ablation zones in healthy porcine liver and to evaluate the appropriateness of immediate post-ablation contrast-enhanced computed tomography (CECT) in detecting RF-ablation dimensions. MATERIAL AND METHODS: We conducted multipolar RFAs in each of the livers of 10 healthy, narcotized and laparotomized domestic pigs by inserting three parallel probes with a constant probe distance and a constant energy supply. In 4 ablations we interrupted hepatic blood flow using Pringle's maneuver. Immediate post-ablation CECT scans were acquired. After euthanasia the livers were sliced perpendicularly to the probes at the probes' active centers. CECT scans were reconstructed equivalently in order to compare RF-lesion size and shape to the macroscopic sections. RESULTS: In total, 19 RF-lesions were analyzed. Every RF-lesion that was ablated during physiological liver perfusion showed an irregular and cloverleaf-like shape (n = 15). Interrupting the hepatic blood flow during RFA led to well-defined, round and homogeneous ablation zones which were 3.8 times larger compared to RF-lesions ablated during continuous hepatic perfusion (n = 4). We found an excellent correlation between immediate post-ablation CECT slices and macroscopic sections when comparing RF-lesion diameters and area, although CECT tended to overestimate ablation dimensions. CONCLUSIONS: The interruption of hepatic blood flow using Pringle's maneuver during multipolar RFA with three applicators significantly reduces heat sink effects of hepatic vessels and generates large and coherent ablation zones. This approach should be considered in each case of ablation planning adjacent to larger hepatic vessels or when ablating larger tumor volumes. Immediate post-ablation CECT has limited value in detecting incomplete RFA periprocedurally.


Assuntos
Ablação por Cateter/métodos , Neoplasias Hepáticas/radioterapia , Fígado/efeitos da radiação , Animais , Modelos Animais de Doenças , Fígado/patologia , Suínos , Tomografia Computadorizada por Raios X
12.
Innov Surg Sci ; 3(4): 245-251, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31579788

RESUMO

Background: Radiofrequency ablation (RFA) represents a treatment option for non-resectable liver malignancies. Larger ablations can be achieved with a temporary hepatic inflow occlusion (Pringle maneuver - PM). However, a PM can induce dehydration and carbonization of the target tissue. The objective of this study was to evaluate the impact of an intermittent PM on the ablation size. Methods: Twenty-five multipolar RFAs were performed in porcine livers ex vivo. A perfused glass tube was used to simulate a natural vessel. The following five test series (each n=5) were conducted: (1) continuous PM, (2-4) intermittent PM, and (5) no PM. Ablations were cut into half. Ablation area, minimal radius, and maximal radius were compared. Results: No change in complete ablation size could be measured between the test series (p>0.05). A small rim of native liver tissue was observed around the glass tube in the test series without PM. A significant increase of ablation area could be measured on the margin of the ablations with an intermittent PM, starting without hepatic inflow occlusion (p<0.05). Conclusion: An intermittent PM did not lead to smaller ablations compared to a continuous or no PM ex vivo. Furthermore, an intermittent PM can increase the ablation area when initial hepatic inflow is succeeded by a PM.

13.
PLoS One ; 12(9): e0184889, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28910382

RESUMO

This study reports morphometric and age-related data of the mandibular canal and the alveolar ridge of the Göttingen Minipig to avoid complications during in vivo testing of endosseus dental implants and to compare these data with the human anatomy. Using 3D computed tomography, six parameters of the mandibular canal as well as the alveolar bone height and the alveolar ridge width were measured in Göttingen Minipigs aged 12, 17 and 21 months. Our null hypothesis assumes that the age and the body mass have an influence on the parameters measured. The study found that the volume, length and depth of the mandibular canal all increase with age. The width of the canal does not change significantly with age. The body mass does not have an influence on any of the measured parameters. The increase in canal volume appears to be due to loss of deep spongy bone in the posterior premolar and molar regions. This reduces the available space for dental implantations, negatively affecting implant stability and potentially the integrity of the inferior alveolar neurovascular bundle. Dynamic anatomical changes occur until 21 months. On ethical grounds, using minipigs younger than 21 months in experimental implant dentistry is inadvisable. Paradoxically the measurements of the 12 months old pigs indicate a closer alignment of their mandibular anatomy to that of humans suggesting that they may be better models for implant studies. Given the variability in mandibular canal dimensions in similar age cohorts, the use of imaging techniques is essential for the selection of individual minipigs for dental prosthetic interventions and thus higher success rates.


Assuntos
Processo Alveolar/diagnóstico por imagem , Implantação Dentária Endo-Óssea/métodos , Mandíbula/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Fatores Etários , Processo Alveolar/anatomia & histologia , Animais , Índice de Massa Corporal , Implantes Dentários , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Mandíbula/anatomia & histologia , Suínos , Porco Miniatura
14.
Laryngorhinootologie ; 96(3): 155-159, 2017 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-28420022

RESUMO

Report of a rare case of severe bleeding from the middle ear cavity after myringotomy. On the basis of the case report, the procedure for such bleeding is discussed in the context of the literature. A 6-year-old boy received a revision myringotomy in an ambulant setting. During the procedure a severe bleeding occurred. The external auditory canal was adequately packed. The patient was extubated and transferred to the clinic as an emergency. Computer tomography of the temporal bone showed the anatomical variant of a dehiscent high jugular bulb, which had been injured. Because no rebleeding occurred, the packing of the ear canal was removed and an explorative tympanoscopy was performed on the third postoperative day. When the tympanomeatal flap was lifted, the defect in the jugular bulb was found. The lesion was covered with Tutopatch® pads and fibrin glue and the auditory canal was packed again. After removal of the packing three weeks postoperatively a properly healed situs was found. No further measures were taken. The injury of a dehiscent jugular bulb in the course of ear surgeries leads to a massive hemorrhage. The case describes the diagnostic and therapeutic procedure for this relatively rare but severe complication.


Assuntos
Procedimentos Cirúrgicos Ambulatórios/efeitos adversos , Orelha Média/diagnóstico por imagem , Veias Jugulares/anormalidades , Veias Jugulares/lesões , Ventilação da Orelha Média/efeitos adversos , Paracentese/efeitos adversos , Hemorragia Pós-Operatória/etiologia , Hemorragia Pós-Operatória/cirurgia , Criança , Adesivo Tecidual de Fibrina/uso terapêutico , Humanos , Veias Jugulares/diagnóstico por imagem , Masculino , Otoscopia , Hemorragia Pós-Operatória/diagnóstico por imagem , Reoperação , Retalhos Cirúrgicos , Tomografia Computadorizada por Raios X
15.
Acta Radiol ; 58(2): 164-169, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27055920

RESUMO

Background Radiofrequency ablation is used to induce thermal necrosis in the treatment of liver metastases. The specific electrical conductivity of a liver metastasis has a distinct influence on the heat formation and resulting tumor ablation within the tissue. Purpose To examine the electrical conductivity σ of human colorectal liver metastases and of tumor-free liver tissue in surgical specimens. Material and Methods Surgical specimens from patients with resectable colorectal liver metastases were used for measurements (size of metastases <30 mm). A four-needle measuring probe was used to determine the electrical conductivity σ of human colorectal liver metastasis (n = 8) and tumor-free liver tissue (n = 5) in a total of five patients. All measurements were performed at 470 kHz, which is the relevant frequency for radiofrequency ablation. The tissue temperature was also measured. Hepatic resections were performed in accordance with common surgical standards. Measurements were performed in the operating theater immediately after resection. Results The median electrical conductivity σ was 0.57 S/m in human colorectal liver metastases at a median temperature of 35.1℃ and 0.35 S/m in tumor-free liver tissue at a median temperature of 34.9℃. The electrical conductivity was significantly higher in tumor tissue than in tumor-free liver tissue ( P = 0.005). There were no differences in tissue temperature between the two groups ( P = 0.883). Conclusion The electrical conductivity is significantly higher in human colorectal liver metastases than in tumor-free liver tissue at a frequency of 470 kHz.


Assuntos
Ablação por Cateter/métodos , Neoplasias Colorretais/patologia , Condutividade Elétrica , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/cirurgia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
Acta Radiol ; 58(2): 218-223, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26966146

RESUMO

Background Surgery in the lesser pelvis is associated with a high complication rate as surgeons are spatially limited by solid anatomic structures and soft tissue borders. So far, only two-dimensional (2D) parameters have been used for risk stratification. Purpose To precisely measure the inner pelvic volume a computed tomography (CT)-based three-dimensional (3D) approach was established and compared to approximations by 2D parameter combinations. Material and Methods Thin-layered multi-slice CT datasets were used retrospectively for slice by slice depiction of the inner pelvic surface. The inner pelvic volume was then automatically compounded. Combinations of two to four 2D dimensions determined in 3D volume rendered reconstructions were correlated with the inner pelvic volume. Pearson's correlation coefficient and Chi square test were used for statistical calculations. Significance level was set at P < 0.05. Results In total 142 patients (91 men, 51 women) aged 64.8 ± 10.6 years at surgery were included in the study. Mean calculated pelvic volume was 1031.13 ± 180.06 cm3 (men, 996.57 ± 172.43 cm3; women, 1093.34 ± 178.39 cm3). Best approximations were obtained by combination of the 2D measurements transverse inlet and pelvic height for men (r = 0.799, P < 0.05) as well as transverse inlet, obstetric conjugate, interspinous distance and pelvic depth for women (r = 0.855, P < 0.05). Conclusion We describe a precise and reproducible CT-based method for pelvic volumetry. A less time consuming but still reliable approximation can be achieved by combination of two to four 2D dimensions.


Assuntos
Pesos e Medidas Corporais/métodos , Imagem Tridimensional/métodos , Pelve/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos
17.
Acta Radiol ; 58(7): 856-860, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27754918

RESUMO

Background The use of computed tomography (CT) scans of the head and cervical spine has markedly increased in patients with blunt minor trauma. The actual likelihood of a combined injury of head and cervical spine following a minor trauma is estimated to be low. Purpose To determine the incidence of such combined injuries in patients with a blunt minor trauma in order to estimate the need to derive improved diagnostic guidelines. Material and Methods A total of 1854 patients were retrospectively analyzed. All cases presented to the emergency department and in all patients combined CT scans of head and cervical spine were conducted. For the following analysis, only 1342 cases with assured blunt minor trauma were included. Data acquisition covered age, sex, and presence of a head injury as well as presence of a cervical spine injury or both. Results Of the 1342 cases, 46.9% were men. The mean age was 65.6 years. CT scans detected a head injury in 116 patients; of these, 70 cases showed an intracranial hemorrhage, 11 cases a skull fracture, and 35 cases an intracranial hemorrhage as well as a skull fracture. An injury of the cervical spine could be detected in 40 patients. A combined injury of the head and cervical spine could be found in one patient. Conclusion The paradigm of the coincidence of cranial and cervical spine injuries should be revised in patients with blunt minor trauma. Valid imaging decision algorithms are strongly needed to clinically detect high-risk patients in order to save limited resources.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/lesões , Cabeça/diagnóstico por imagem , Traumatismo Múltiplo/diagnóstico por imagem , Traumatismo Múltiplo/epidemiologia , Crânio/diagnóstico por imagem , Crânio/lesões , Tomografia Computadorizada por Raios X , Ferimentos não Penetrantes/diagnóstico por imagem , Ferimentos não Penetrantes/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Incidência , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Exposição à Radiação , Estudos Retrospectivos
18.
Clin Hemorheol Microcirc ; 64(3): 491-499, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27858704

RESUMO

BACKGROUND: Continuing research ex vivo and in vivo with animal models is performed to advance the oncological safety of radiofrequency ablation (RFA) of liver tumors. In these experiments, frequently imaging modalities (e.g. MRI or CT) or macro-morphological measurements are used to determine the full extent of the different ablation zones inside of RFA lesions. However, no systematic study has been performed so far, which verified the accuracy of the macro-morphological findings. Therefore, the present study aimed to correlate histological and gross pathological findings of bipolar radiofrequency ablation zones of porcine livers with regard to cell viability in vivo. METHODS: Bipolar RFA was performed in the liver of anaesthetized female domestic pigs under CT-guidance using an internally cooled 20 mm RFA applicator. Afterwards RFA cross sections of the liver were made in a perpendicular orientation to the applicator. Ablation zones were initially documented by photography and thereafter prepared for histological analysis. Latter was based on HE-staining and NADH-diaphorase cell viability staining. Micro- and macro-morphological sections were digitally analyzed along the cross-section area for statistical correlation. RESULTS: Three different RF ablation zones could be differentiated. A central zone showing no cell viability (white zone) was surrounded by a red zone. The red zone could be divided into an inner zone of viable and non-viable cells (red zone 1), followed by a zone of edema with mostly viable cells (red zone 2).Micro- and macro-morphological data showed a strong correlation for the white zone (r = 0.95, p < 0.01), the red zone 1 (r = 0.85, p < 0.01), and the red zone 2 (r = 0.89, p < 0.01). CONCLUSION: White zone and red zone could clearly be distinguished in gross pathology and histology after bipolar RFA of porcine liver tissue in vivo. The red zone could be differentiated into an inner zone of viable and non-viable cells and an outer zone with high cell viability and intercellular edema. A strong correlation of micro- and macro-morphology could be shown for all three ablation zones. With this knowledge, gross pathological examination can be used as a reliable indicator of lethally damaged tissue in bipolar RFA of in vivo porcine liver.


Assuntos
Ablação por Cateter/métodos , Neoplasias Hepáticas/radioterapia , Fígado/patologia , Animais , Modelos Animais de Doenças , Feminino , Neoplasias Hepáticas/patologia , Suínos
19.
Clin Hemorheol Microcirc ; 61(2): 323-31, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26410879

RESUMO

BACKGROUND: Radiofrequency ablation (RFA) is an evolving technique in treatment of hepatic malignant tumors. By heating local tissue it leads to coagulative necrotic areas around the ablation probe. Temperature falls with increasing distance to the probe, risking incomplete necrosis at the margins of the RFA-induced lesion. Therefore, immediate non-invasive and precise detection of incomplete ablation is necessary for early enlargement of the ablation if needed. OBJECTIVES: This in vivo pig study compares early experiences of immediate post-interventional computed tomography (CT) perfusion volume analysis to macroscopic and CT image evaluation in healthy pig liver. MATERIAL AND METHODS: RFA was performed in vivo in healthy pig livers. Different CT perfusion algorithms (Maximum slope analysis and Patlak plot) were used to quantify three different perfusion parameters. Data points were acquired from rectangular grids. These grids were semiautomatically overlayed to macroscopic images documented after liver explantation. Each data point was visually assigned to zones defined as "inner" and "outer necrotic zone", "margin" or "vital tissue". RESULTS: Significant differences between necrotic zones and vital tissue are shown for equivalent blood volume (p <  0.0001), arterial flow (p <  0.01) and flow extraction product (p <  0.001). Looking at equivalent blood volume and flow extraction product, there were also significant differences (EquivBV: p <  0.0001, FE: p <  0.001) between margins, necrotic and vital areas. CONCLUSIONS: In a porcine model these early results could show that all of the used CT perfusion parameters allowed discrimination of necrosis from vital tissue after RFA at high levels of significance. In addition, the parameters EquivBV and FE that give an estimate of the tissue blood volume and the permeability, were able to precisely discern different zones also seen macroscopically. From this data CT perfusion analysis could be precise tool for measurement and visualization of ablated liver lesions and for immediate detection of incomplete ablation areas.


Assuntos
Ablação por Cateter , Neoplasias Hepáticas/cirurgia , Fígado/patologia , Imagem de Perfusão , Animais , Fígado/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Modelos Animais , Necrose/diagnóstico por imagem , Suínos , Tomografia Computadorizada por Raios X
20.
Clin Hemorheol Microcirc ; 58(1): 77-87, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25248350

RESUMO

Radiofrequency ablation (RFA) has shown to be a reasonable alternative for the treatment of hepatic tumors and metastases although multiple limitations remain. Cooling effects due to larger vessels can prevent complete coverage and may lead to early tumor relapse. This preliminary in vivo pig study combines the use of multipolar RFA with three applicators (six electrodes) and interrupted liver perfusion using Pringle's maneuver to overcome the most serious limitations. Furthermore, immediate detection of incomplete RFA is important to revise ablation. We used contrast enhanced computed tomography (CECT) to evaluate post ablation results in comparison to macroscopic images in healthy pig liver. We found significantly (p = 0.001) larger ablation zones and no affection by larger vessels with interrupted liver perfusion. This allows effective RFA for larger tumors. Immediate postinterventional CECT provided comparable results (r = 0.985) to macroscopic evaluation.


Assuntos
Ablação por Cateter , Neoplasias Hepáticas/patologia , Animais , Meios de Contraste/química , Eletrodos , Fígado/metabolismo , Fígado/patologia , Metástase Neoplásica , Recidiva Local de Neoplasia , Perfusão , Ondas de Rádio , Suínos , Tomografia Computadorizada por Raios X
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