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  • 1
    Keywords: MODEL ; MODELS ; PROSTATE ; THERAPY ; imaging ; VOLUME ; DRUG ; ACCURACY ; TIME ; MRI ; treatment ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; TRIAL ; BENIGN ; nuclear medicine ; LOCATION ; monitoring ; EXTENSION ; HYPERPLASIA ; BENIGN PROSTATIC HYPERPLASIA ; ACCURATE ; COIL ; prostate volume ; THERMOTHERAPY ; TRANSRECTAL ULTRASOUND
    Abstract: Objectives: We sought to evaluate the capabilities of different magnetic resonance imaging (MRI)-based methodologies for measuring prostate volume. Materials and Methods: Twenty-four male beagles with benign prostatic hyperplasia were enrolled in a drug trial and imaged at 5 time points. A total of 120 prostate volumes were determined by MRI-based semiautomated segmentation. For planimetric assessment, 8 diameter locations were determined in the axial and coronal plane of the MRI slice with maximum extension of the prostate. Thirteen calculation models based on these diameters were determined by comparison to the reference volume and evaluated during treatment. Results: The segmented MRI prostate volume significantly correlated with post necropsy Volume. The best diameter-based model also worked very well for monitoring prostate volume of dogs under treatment. Conclusions: MRI-based segmentation is highly accurate in assessing prostate volume. Diameter-based measurements are closely correlated to the segmented prostate volume and are feasible to monitor therapy
    Type of Publication: Journal article published
    PubMed ID: 15770143
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  • 2
    Keywords: Germany ; THERAPY ; CLASSIFICATION ; RISK ; PATIENT ; treatment ; LESIONS ; EXPERIENCE ; REPAIR ; HIGH-RISK ; SELECTION ; RECONSTRUCTION ; MANAGEMENT ; SURGICAL-TREATMENT ; ABDOMINAL AORTIC-ANEURYSM ; aneurysm ; ARTERY ANEURYSMS ; endograft ; endovascular ; ENDOVASCULAR TREATMENT ; GRAFTS ; iliac artery ; MIDTERM EXPERIENCE
    Abstract: Isolated iliac aneurysms (IIA) are uncommon lesions that require surgical repair to prevent rupture. The aim of this article is to give an update on the current surgical management of IIA. This report also evaluates the application of endovascular repair in IIA, based on a recent Pubmed search and on our own experience in the interventional field: Open reconstruction achieves good longterm results and still represents the golden standard in surgical treatment of IIA. Transluminally placed endovascular stent grafts can be successfully used to exclude isolated iliac aneurysms in selected high risk patients with suitable anatomy. A classification based on aneurysm morphology is useful for patient selection. The value of endovascular therapy has yet to be determined
    Type of Publication: Journal article published
    PubMed ID: 16485205
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  • 3
    Keywords: Germany ; THERAPY ; FOLLOW-UP ; SYSTEM ; SYSTEMS ; MORTALITY ; RISK ; computed tomography ; SURGERY ; PATIENT ; treatment ; DESIGN ; AGE ; REPAIR ; RATES ; tomography ; COMPUTED-TOMOGRAPHY ; COMPLICATIONS ; DISSECTION ; STROKE ; THORACIC AORTA ; THROMBOSIS ; methods ; Male ; VARIABLES ; endovascular ; GRAFTS ; ANEURYSM REPAIR ; DISSECTIONS ; PHANTOMS ; PULSATILE FLOW ; SINGLE-CENTER ; STENT-GRAFT PLACEMENT ; TRUE-LUMEN COLLAPSE
    Abstract: Objective: To outline the complications after endovascular repair in patients with acute symptomatic and chronic expanding Stanford type B aortic dissections. Methods: Between 1997 and 2004, of 125 patients with acute and chronic aortic type B dissections, 88 were treated conservatively. Thirty-seven patients ( 29 male, mean age 58 years, range 30-82 years) underwent endovascular repair (30%) using 44 stent grafts of 3 different designs: Excluder ( W. L. Gore & Associates, Inc, Flagstaff, Ariz), Talent ( Medtronic Vascular, Santa Rosa, Calif), and Endofit (Endomed, Inc, Phoenix, Ariz). Indications for treatment were acute symptomatic type B dissection in 15 patients, chronic expanding aortic dissection greater than 55 mm in 14, rupture in 3, and simultaneous type A repair in 5 patients. Twenty-two operations were performed on an emergency basis. Patient characteristics, procedural variables, outcome, and complications were prospectively recorded. All patients underwent follow-up by computed tomography before discharge, at 6 and 12 months, and annually thereafter ( mean follow-up: 24 months). Results: Correct deployment was achieved in 97% of cases. There were no instances of primary conversion, paraplegia, or stroke. Complete false lumen thrombosis was observed in 11 patients (44%). Perioperative complication rate was 22%. Thirty-day mortality rate in acute and chronic dissections was 19% and 0%, respectively. Freedom from aortic reintervention was 81%, 73%, and 68%, freedom from late rupture was 97%, 90%, and 80%, and overall success rate was 76%, 65%, and 57% at 1, 2, and 5 years, respectively. Results for patients with chronic dissections are significantly ( P =.038) better than results in those with acute dissections. Conclusions: Despite the minimally invasive approach, the complication and mortality rates for endovascular therapy of aortic dissections are still high. Frank reporting of these sequelae is if great importance to clarify the recent limitations of the method
    Type of Publication: Journal article published
    PubMed ID: 16872963
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  • 4
    Keywords: brain ; RECEPTOR ; ANGIOGENESIS ; APOPTOSIS ; CELLS ; EXPRESSION ; GROWTH ; IN-VITRO ; INVASION ; proliferation ; SURVIVAL ; tumor ; TUMOR-CELLS ; Germany ; human ; IN-VIVO ; INHIBITION ; KINASE ; THERAPY ; VITRO ; DISTINCT ; TUMORS ; validation ; LINES ; MICE ; TIME ; IDENTIFICATION ; METASTASIS ; CELL-LINE ; leukemia ; LINE ; MIGRATION ; OVEREXPRESSION ; CANCER-THERAPY ; GLIOMAS ; INVITRO ; CELL-GROWTH ; signaling ; BRAIN-TUMORS ; GLIOMA ; PROTOONCOGENE ; LEVEL ; cell migration ; in vivo ; GLIOBLASTOMA ; receptor tyrosine kinase ; GAS6
    Abstract: Malignant gliomas remain incurable brain tumors because of their diffuse-invasive growth. So far, the genetic and molecular events underlying gliomagenesis are poorly understood. In this study, we have identified the receptor tyrosine kinase Axl as a mediator of glioma growth and invasion. We demonstrate that Axl and its ligand Gas6 are overexpressed in human glioma cell lines and that Axl is activated under baseline conditions. Furthermore, AxI is expressed at high levels in human malignant glioma. Inhibition of Axl signaling by overexpression of a dominant-negative receptor mutant (AXL-DN) suppressed experimental gliomagenesis (growth inhibition 〉 85%, P 〈 0.05) and resulted in long-term survival of mice after intracerebral glioma cell implantation when compared with Axl wild-type (AXL-WT) transfected tumor cells (survival times: AXL-WT, 10 days; AXL-DN, 〉 72 days). A detailed analysis of the distinct hallmarks of glioma pathology, such as cell proliferation, migration, and invasion and tumor angiogenesis, revealed that inhibition of Axl signaling interfered with cell proliferation (inhibition 30% versus AXL-WT), glioma cell migration (inhibition 90% versus mock and AXL-WT, P 〈 0.05), and invasion (inhibition 62% and 79% versus mock and AXL-WT, respectively; P 〈 0.05). This study describes the identification, functional manipulation, in vitro and in vivo validation, and preclinical therapeutic inhibition of a target receptor tyrosine kinase mediating glioma growth and invasion. Our findings implicate Axl in gliomagenesis and validate it as a promising target for the development of approaches toward a therapy of these highly aggressive but, as yet, therapy-refractory, tumors
    Type of Publication: Journal article published
    PubMed ID: 16585512
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  • 5
    Keywords: Germany ; THERAPY ; chest ; CT ; imaging ; segmentation ; TOOL ; VOLUME ; NEW-YORK ; NUCLEAR-MEDICINE ; TIME ; PATIENT ; QUALITY ; CARE ; REPRODUCIBILITY ; metastases ; MELANOMA ; VARIABILITY ; MALIGNANT-MELANOMA ; malignant melanoma ; nuclear medicine ; FEASIBILITY ; radiology ; ONCOLOGY ; RE ; THERAPIES ; monitoring ; SOFTWARE ; SOLID TUMORS ; analysis ; methods ; NUCLEAR ; CRITERIA ; USA ; lymph node metastases ; lymph nodes ; CANCER-TREATMENT ; MULTISLICE CT ; SMALL PULMONARY NODULES ; therapy monitoring ; postprocessing ; MEDICINE ; VALUES ; INTEROBSERVER ; RECIST ; RECIST CRITERIA ; RESPONSE ASSESSMENT ; volumetric analysis
    Abstract: Therapy monitoring in oncological patient care requires accurate and reliable imaging and post-processing methods. RECIST criteria are the current standard, with inherent disadvantages. The aim of this study was to investigate the feasibility of semi-automated volumetric analysis of lymph node metastases in patients with malignant melanoma compared to manual volumetric analysis and RECIST. Multislice CT was performed in 47 patients, covering the chest, abdomen and pelvis. In total, 227 suspicious, enlarged lymph nodes were evaluated retrospectively by two radiologists regarding diameters (RECIST), manually measured volume by placement of ROIs and semi-automated volumetric analysis. Volume (ml), quality of segmentation (++/-) and time effort (s) were evaluated in the study. The semi-automated volumetric analysis software tool was rated acceptable to excellent in 81% of all cases (reader 1) and 79% (reader 2). Median time for the entire segmentation process and necessary corrections was shorter with the semi-automated software than by manual segmentation. Bland-Altman plots showed a significantly lower interobserver variability for semi-automated volumetric than for RECIST measurements. The study demonstrated feasibility of volumetric analysis of lymph node metastases. The software allows a fast and robust segmentation in up to 80% of all cases. Ease of use and time needed are acceptable for application in the clinical routine. Variability and interuser bias were reduced to about one third of the values found for RECIST measurements
    Type of Publication: Journal article published
    PubMed ID: 18274757
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  • 6
    Keywords: ANGIOGENESIS ; CANCER ; SURVIVAL ; tumor ; Germany ; THERAPY ; DENSITY ; DIAGNOSIS ; imaging ; liver ; NEW-YORK ; SAMPLE ; SAMPLES ; TISSUE ; TUMORS ; NUCLEAR-MEDICINE ; PATIENT ; BIOMARKERS ; TISSUES ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; BREAST ; immunohistochemistry ; REGION ; REGIONS ; MUSCLE ; PARAMETERS ; NORMAL TISSUE ; SERIES ; CONTRAST-ENHANCED MRI ; nuclear medicine ; ASBESTOS ; mesothelioma ; MALIGNANT MESOTHELIOMA ; LUNG-CARCINOMA ; HETEROGENEITY ; radiology ; RE ; THERAPIES ; monitoring ; dynamic contrast enhanced MRI ; biomarker ; analysis ; methods ; SUBTYPES ; NUCLEAR ; USA ; correlation ; spleen ; Aorta ; microvascular density ; MEDICINE ; quantitative ; PHARMACOKINETIC ANALYSIS ; DCE-MRI ; neoplasm ; CD-34 ; IMAGING BIOMARKER
    Abstract: Rationale and Objectives. Malignant mesothelioma (MM) of the pleura is an aggressive and often fatal neoplasm. Because MM frequently demonstrates marked angiogenesis, it may be responsive to antiangiogenic therapy, but effective methods for selecting and monitoring of patients are further needed. We employed dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and quantitative immunohistochemistry (IHC) to characterize the microvascularity of MM using both a physiologic and ultrastructural method. Materials and Methods. Nineteen patients diagnosed with MM were enrolled and DCE-MRI was performed before antiangiogenic treatment. For each patient, tumor regions were characterized by their DCE-MRI-derived pharmacokinetic parameters (Amp, k(ep), k(el)), which were also compared to those of normal tissue (aorta, liver, spleen, and muscle). In addition, quantitative ITIC of representative samples was performed with CD-34 staining to compare the calculated microvessel density (MVD) results with DCE-MRI results. Results. MM demonstrated markedly abnormal pharmacokinetic properties compared with normal tissues. Among the parameters tested, Amp was significantly different in MM (P :5.001) compared to normal organs. Despite the observation that the MVD of mesotheliomas in this series was high compared to other tumors, DCE-MRI pharmacokinetic parameters had a moderately positive correlation with MVD (r = 0.5). Conclusions. DCE-MRI and IHC can be used in patients with MM to visualize tumor microvascularity and to characterize tumor heterogeneity. DCE-MRI and IHC results positively correlated, though moderately, but these two methods present as essential tumor biomarkers. This multimodal characterization may be useful in selecting possible tumor subtypes that would benefit from antiangiogenic therapy
    Type of Publication: Journal article published
    PubMed ID: 18423312
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  • 7
    Keywords: THERAPY ; CT ; QUANTIFICATION ; VOLUME ; REPRODUCIBILITY ; malignant melanoma ; SOLID TUMORS ; CRITERIA ; lymph nodes ; SMALL PULMONARY NODULES ; therapy monitoring ; PRECISION ; RECIST ; volumetric analysis ; COMPUTER-AIDED VOLUMETRY ; INTEROBSERVER-VARIABILITY ; VIVO PORCINE LUNGS
    Abstract: OBJECTIVE: Quantification of tumour burden in oncology requires accurate and reproducible evaluation. The current standard is RECIST measurement with its inherent disadvantages. Volumetric analysis is an alternative for therapy monitoring. The aim of this study was to evaluate the feasibility of volumetric analysis of lymph node metastases using a software prototype in a follow-up setting. METHODS: MSCT was performed in 50 patients covering the chest, abdomen and pelvis. A total of 174 suspicious lymph nodes were evaluated by two radiologists regarding short axis diameters and volumetric analysis using semi-automated software. Quality of segmentation, time, maximum diameter and volume were documented. Variability of the derived change rates was computed as the standard deviation of the difference of the obtained respective change rates. RESULTS: The software performance provides robust volumetric analysis. Quality of segmentation was rated acceptable to excellent in 76-79% by each reader. Mean time spent per lesion was 38 s. The variability of change in effective diameters was 10.6%; for change rates of RECIST maximum diameter variability was 27.5%. CONCLUSION: Semi-automated volumetric analysis allows fast and convenient segmentation of most lymph node metastases. Compared with RECIST the inter-observer-variability in baseline and follow-up is reduced. This should principally allow subtle changes to be subclassified within the RECIST stable range as minor response [-15% to +10%].
    Type of Publication: Journal article published
    PubMed ID: 20953870
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  • 8
    Keywords: ANGIOGENESIS ; SURVIVAL ; tumor ; CELL LUNG-CANCER ; ENDOTHELIAL GROWTH-FACTOR ; IN-VIVO ; MODEL ; THERAPY ; VIVO ; DIAGNOSIS ; FOLLOW-UP ; TISSUE ; TUMORS ; PATIENT ; MRI ; BIOLOGY ; CYCLE ; treatment ; BREAST ; MALIGNANCIES ; METASTASIS ; chemotherapy ; REGION ; REGIONS ; PARAMETERS ; POSITRON-EMISSION-TOMOGRAPHY ; BENIGN ; Jun ; COMPUTED-TOMOGRAPHY ; CONTRAST-ENHANCED MRI ; TUMOR ANGIOGENESIS ; PLEURAL MESOTHELIOMA ; FEASIBILITY ; ELIMINATION ; MANAGEMENT ; MALIGNANCY ; GEMCITABINE ; malignant pleural mesothelioma ; SOLID TUMORS ; dynamic contrast enhanced MRI ; FACTOR EXPRESSION ; MAP ; in vivo ; PREDICTOR ; VARIETIES ; kinetic parameters ; dCE MRI ; PHARMACOKINETIC PARAMETERS ; therapy monitoring ; two-compartment model
    Abstract: Study objective: Dynamic contrast-enhanced MRI (DCE-MRI) followed by pharmacokinetic analysis has been successfully used in a variety of solid tumors. The aims of this study were to evaluate the feasibility of DCE-MRI in malignant pleural mesothelioma (MPM), to differentiate benign from pathologic tissue and compare pharmacokinetic with clinical parameters and survival in order to map out its microcirculation; and to compare pharmacokinetic with clinical parameter and survival in order to improve our understanding of the in vivo biology of this malignancy. Methods: Nineteen patients with a diagnosis of MPM who were scheduled to receive chemotherapy with gemcitabine were enrolled in the study. DCE-MRI was performed before treatment (n = 19) and after the third cycle (n = 12) and sixth cycle (n = 7) of chemotherapy. An established pharmacokinetic two-compartment model was used to analyze DCE-MRI. Tumor regions were characterized by the pharmacokinetic parameters amplitude (Amp), redistribution rate constant (kep), and elimination rate constant (kel). Kinetic parameters of tumor tissue and normal tissue were compared using the Student t test. Patients were classified as clinical responders or nonresponders according to clinical outcome, and these groups were compared with the pharmacokinetic parameters derived from DCE-MRI. Results: Normal and tumor tissue could be distinguished by the pharmacokinetic parameters Amp and kel (p 〈= 0.001). Clinical responders had a median kep value within the tumor of 2.6 min, while nonresponders showed a higher value (3.6 min), which coincided with longer survival (780 days vs 460 days). Conclusions: DCE-MRI can be used in patients with MPM to assess tumor microvascular properties and to demonstrate tumor heterogeneity for therapy monitoring. High pretherapeutic values of kep within the tumor correlated with a poor overall response to therapy
    Type of Publication: Journal article published
    PubMed ID: 16778277
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  • 9
    Keywords: brain ; tumor ; AGENTS ; neoplasms ; PERFUSION ; THERAPY ; DIAGNOSIS ; FOLLOW-UP ; imaging ; SYSTEM ; MORTALITY ; DRUG ; TISSUE ; TUMORS ; MECHANISM ; CONTRAST ; mechanisms ; MRI ; SIGNAL ; FIELD ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; NERVOUS-SYSTEM ; EXPERIENCE ; CENTRAL-NERVOUS-SYSTEM ; pathology ; CONTRAST-ENHANCED MRI ; contrast media ; DIFFERENTIAL-DIAGNOSIS ; YOUNG ; ADULT ; ADULTS ; BRAIN-TUMORS ; dynamic contrast enhanced MRI ; ENHANCEMENT ; blood-brain barrier ; brain tumors ; TUMOR TISSUE ; technique ; functional imaging ; BARRIER ; nervous system ; central nervous system ; BLOOD-BRAIN-BARRIER ; CLINICAL-EXPERIENCE ; PITFALLS
    Abstract: Brain tumors are one of the most common neoplasms in young adults and are associated with a high mortality and disability rate. Magnetic resonance imaging (MRI) is widely accepted to be the most sensitive imaging modality in the assessment of cerebral neoplasms. Because the detection, characterization, and exact delineation of brain tumors require a high lesion contrast that depends on the signal of the lesion in relation to the surrounding tissue, contrast media is given routinely. Anatomical and functional, contrast agent-based MRI techniques allow for a better differential diagnosis, grading, and especially therapy decision, planing, and follow-up. In this article, the basics of contrast enhancement of brain tumors will be reviewed. The underlying pathology of a disrupted blood-brain barrier and drug influences will be discussed. An overview of the currently available contrast media and the influences of dosage, field strength, and application on the tumor tissue contrast will be given. Challenging, contrast-enhanced, functional imaging techniques, such as perfusion MRI and dynamic contrast-enhanced MRI, are presented both from the technical side and the clinical experience in the assessment of brain tumors. The advantages over conventional, anatomical MRI techniques will be discussed as well as possible pitfalls and drawbacks.
    Type of Publication: Journal article published
    PubMed ID: 17198225
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  • 10
    Keywords: CANCER ; tumor ; AGENTS ; evaluation ; neoplasms ; THERAPY ; DIAGNOSIS ; FOLLOW-UP ; SUPPORT ; LONG-TERM ; PATIENT ; treatment ; CARE ; HUMANS ; REQUIRES ; GUIDELINES ; AGENT ; radiology ; review ; THERAPIES ; THERAPY RESPONSE ; WHOLE-BODY ; TERM-FOLLOW-UP ; methods ; LONG ; therapeutic use ; Antineoplastic Agents ; TUMOR RESPONSE ; Guideline ; A ; Diagnostic Imaging ; Radiation-Sensitizing Agents
    Abstract: Oncological patient care requires long term follow-up in order to estimate effectiveness of existing and new treatment choices. Image-based assessment of whole body tumour burden is commonly used for that purpose. The WHO response criteria were established in 1979 proposing bi-dimensional tumor measurements. New RECIST guidelines appeared in 2000 relying on only the longest diameter (uni-dimensional) measurements. Obviously, a change in tumour size is only one potential surrogate for therapy response which not necessarily reflects the biologic activity of the tumour or the effect of particular therapy. Thus, the evaluation of biological, metabolic or molecular properties of a tumor and its changes might be an attractive means to assess the response to therapy sensitively and early
    Type of Publication: Journal article published
    PubMed ID: 18806739
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