0000000000011732
AUTHOR
T. Achenbach
Quantification and Characterization of Pulmonary Emphysema in Multislice-CT
The new technology of the Multislice-CT provides volume data sets with approximately isotropic resolution, which permits a non invasive measurement of diffuse lung diseases like emphysema in the 3D space. The aim of our project is the development of a full automatic 3D CAD (Computer Aided Diagnosis) software tool for detection, quantification and characterization of emphysema in a thoracic CT data set. It should supply independently an analysis of an image data set to support the physician in clinical daily routine. In this paper we describe the developed 3D algorithms for the segmentation of the tracheo-bronchial tree, the lungs and the emphysema regions. We present different emphysema des…
Cryotherapy for liver metastases
Cryotherapy is undergoing a renaissance in the treatment of nonresectable liver tumors. In a prospective case control study we assessed the morbidity, mortality, and efficacy of hepatic cryotherapy for liver metastases. Between January 1996 and September 1999 a total of 54 cryosurgical procedures were performed on 49 patients (median age 66 years, 21 women) with liver metastases. Patient, tumor, and operative details were recorded prospectively. Liver metastases originated from colorectal cancer (n=37), gastric cancer (n=3), renal cell carcinoma (n=2), and other primaries (n=7). Median follow-up was 13 months (1-32). The median number of liver metastases was 3 (range 1-10) with a median dia…
Influence of pixel size on quantification of airway wall thickness in computed tomography.
Objectives: The purpose of this study was to determine the point where a further decrease in voxel size does not result in better automatic quantification of the bronchial wall thickness by using 2 different assessment techniques. Materials and Methods: The results from the commonly used full-width-at-half-maximum (FWHM) principle and a new technique (integral-based method [IBM]) were compared for thin-section multidetector computed tomography (MDCT) data sets from an airway phantom containing 10 different tubular airway phantoms and in a human subsegmental bronchus in vivo. Correlation with the actual wall thickness and comparison of the wall thicknesses assessed for different voxel sizes …
Robotic total knee arthroplastyThe accuracy of CT-based component placement
Accurate alignment of the components in total knee arthroplasty is important. By use of postoperative CT controls, we studied the ability of a robotic effector to accurately place and align total knee arthroplasty (TKA) components according to a purely CT-based preoperative plan.Robotic TKA was performed in 13 patients (6 men) with primary gonarthrosis. Locator screws were placed into femur and tibia under spinal anesthesia. A CT-scan including the femoral head, knee and ankle was performed. In the preoperative planning software, virtual components were positioned into the CT volume. In a second operation, the robot milled femur and tibia with a high-speed milling tool according to the preo…
Repräsentiert der HRCT-Emphysemindex die gesamte Lunge?
Purpose: Comparison of emphysema index derived of thin section MD-CT of the entire lung volume and HRCT, simulated by calculation of every twentieth image of the whole data-set. Materials and Methods: Pulmonary emphysema was quantified by semiautomatic, segmentation of lung borders and assessment of lung volume and emphysema volume within these borders. The emphysema index (pixel index) was calculated. Statistical analysis was done by the sign-test and Bland-Altman-analysis. Results: Median lung volume, emphysema volume and emphysema index are significantly higher in simulated HRCT. Median lung volume (emphysema volume) calculated by HRCT is 5118 ml (407 ml) and 5040 ml (367 ml) calculated …
Selbstorganisierende neuronale Netze zur automatischen Detektion und Klassifikation von Kontrast(mittel)-verstärkten Läsionen in der dynamischen MR-Mammographie
Purpose: Investigation and statistical evaluation of "Self-Organizing Maps," a special type of neural networks in the field of artificial intelligence, classifying contrast enhancing lesions in dynamic MR-mammography. Material and Methods: 176 investigations with proven histology after core biopsy or operation were randomly divided into two groups. Several Self-Organizing Maps were trained by investigations of the first group to detect and classify contrast enhancing lesions in dynamic MR-mammography. Each single pixel's signal/time curve of all patients within the second group was analyzed by the Self-Organizing Maps. The likelihood of malignancy was visualized by color overlays on the MR-…
Dissemination of hepatocellular carcinoma is mediated via chemokine receptor CXCR4
In different tumour entities, expression of the chemokine receptor 4 (CXCR4) has been linked to tumour dissemination and poor prognosis. Therefore, we evaluated, if the expression of CXCR4 exerts similar effects in human hepatocellular carcinoma (HCC). Expression analysis and functional assays were performed in vitro to elucidate the impact of CXCL12 on human hepatoma cells lines. In addition, expression of CXCR4 was evaluated in 39 patients with HCC semiquantitatively and correlated with both, tumour and patients characteristics. Human HCC and hepatoma cell lines displayed variable intensities of CXCR4 expression. Loss of p53 function did not impact on CXCR4 expression. Exposure to CXCL12 …
About Objective 3-D Analysis of Airway Geometry in Computerized Tomography
The technology of multislice X-ray computed tomography (MSCT) provides volume data sets with approximately isotropic resolution, which permits a noninvasive 3-D measurement and quantification of airway geometry. In different diseases, like emphysema, chronic obstructive pulmonary disease (COPD), or cystic fribrosis, changes in lung parenchyma are associated with an increase in airway wall thickness. In this paper, we describe an objective measuring method of the airway geometry in the 3-D space. The limited spatial resolution of clinical CT scanners in comparison to thin structures like airway walls causes difficulties in the measurement of the density and the thickness of these structures.…
Differences of airway dimensions between patients with and without bronchiolitis obliterans syndrome after lung transplantation-Computer-assisted quantification of computed tomography.
Abstract Background The aim of our retrospective study was to determine whether a dedicated software for assessment of airway morphology can detect differences in airway dimensions between patients with and without bronchiolitis obliterans syndrome (BOS), regarded as the clinical correlate of chronic lung allograft rejection. Methods 12 patients with and 14 patients without diagnosis of BOS were enrolled in the study. Evaluation of bronchial wall area percentage (WA%) and bronchial wall thickness (WT) in all follow-up CT scans was performed using a semiautomatic airway assessment tool. We assessed temporal changes (ΔWA%, ΔWT) and compared these morphological parameters with forced expirator…
Computerunterstützte Diagnostik in der Thoraxradiologie - aktuelle Schwerpunkte und Techniken
The proliferation of digital data sets and the increasing amount of images, e. g. through the use of multislice spiral CT or multiple follow-up examinations in the context of new therapies, are ideal prerequisites for computer-aided diagnosis (CAD) in chest radiology. Multiple studies have described the applications and advantages of computer assistance in performing different diagnostic tasks. More powerful computers will enable the introduction of these systems into the clinical routine and could provide an enormous increase in morphological and functional information. The commercial introduction of tools for detection and visualization of pulmonary nodules has already begun. This is one …
Chemokine receptor CCR7 enhances intrahepatic and lymphatic dissemination of human hepatocellular cancer.
Despite many pathophysiological analyses, the process of tumor dissemination of hepatocellular carcinoma (HCC) remains vague. In diverse tumor entities, expression of the chemokine receptor, CCR7, has been linked to tumor dissemination and poor prognosis. Therefore, we evaluated, whether CCR7 exerts similar effects in human HCC. CCR7 expression analysis was performed in vitro on human hepatoma cell lines (Huh7, Hep3B, wt HepG2, p53 dominant negative transfected HepG2). In addition, CCR7 expression was evaluated in 39 patients with hepatocellular cancer and correlated with both, tumor and patients characteristics. Human hepatocellular carcinoma samples and hepatoma cell lines displayed varia…
Accuracy of automatic airway morphometry in computed tomography-correlation of radiological-pathological findings.
Abstract Objectives Airway morphology shows characteristic changes in different pathologies. This study assesses the accuracy of a current automatic airway assessment technique by correlating CT images of porcine airways to histological slices of the same localization. Materials and methods Four isolated and ventilated porcine lungs were frozen in a liquid nitrogen bath and examined with a CT scanner (MDCT). This technique both preserved normal radiomorphological appearance and made it possible to slice the specimens for histological examination for subsequent correlation. The parameters wall thickness (WT), wall percentage (WP), and total diameter (TD) were assessed by computer-aided measu…
Vollautomatische Detektion und Quantifizierung des Lungenemphysems in Dünnschicht-MD-CT des Thorax durch eine neue, speziell entwickelte Software
Purpose: Introduction of a novel software tool (YACTA - yet another CT analyzer) for detection and quantification of pulmonary emphysema in thin-slice chest MDCT data sets. Materials and Methods: Consisting of grey-level threshold-based algorithms (e. g., region-growing), expert rules and morphological image postprocessing YACTA segments the tracheobronchial tree prior to the detection and quantification of pulmonary emphysema. In addition to general parameters, such as the mean lung density (MLD) and the emphysema index (EI - also described as pixel index PI), the previously described bullae index (BI) is transformed into a three-dimensional parameter for a morphological description of emp…
Chemoembolization for primary liver cancer
Abstract Aims: For most patients with primary liver cancer surgical treatment is not feasible and prognosis without treatment is poor. We aimed to assess the morbidity and efficacy of transarterial chemoembolization (TACE) with lipiodol and mitomycin C in these patients in a prospective case-control study. Methods: From August 1996 to May 2000 22 patients with non-resectable hepatocellular carcinoma were treated with TACE. In case of radiological or tumour-marker response, treatment was repeated after 4–6 weeks, up to seven times per patient. Results: Morbidity was 23% and usually minor, no patient died within 30 days of treatment. A decrease in size of the reference tumour or constant tumo…
Die Kryotherapie — eine Erweiterung des Behandlungsspektrums von Lebermetastasen
Von 1/96 bis 9/99 wurden bei 49 Patienten mit Lebermetastasen 54 kryo- therapeutische Eingriffe durchgefuhrt. Bei 37 Patienten lagen colorectale Primartumoren vor. Bei 28 Patienten kam die Kryotherapie in Kombination mit Leberresektion zur Anwendung. Ein Patient starb im perioperativen Verlauf und 13 Patienten (27%) entwickelten Komplikationen. Bei 19 der 25 Patienten (76%) mit praoperativ erhohten CEA-Spiegeln bei colorectalen Metastasen lagen diese postoperativ im Normbereich. Nach einer medianen Nachbeobachtung von 13 Monaten haben 28 Patienten ein Tumorrezidiv entwickelt: 14 hepatisch,13 hepatisch und extrahepatisch (davon je 4 unter Beteiligung der Kryoablationsstelle) und 1 extrahepat…
Analyse von Bronchien in der Multislice-CT
Es wird eine Methode zum objektiven Bestimmen der Wanddicke und des Gesamt durchmessers von Bronchien in der 3-dimensionalen Computertomographie vorgestellt. Die Methode wurde erfolgreich an Phantomen evaluiert. Erste Studien sowohl an tierischen als auch an menschlichen Bronchien verliefen erfolgversprechend.