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  • imaging  (11)
  • ANGIOGRAPHY  (7)
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  • 1
    Keywords: Diagnostic Imaging ; radiology ; MULTISLICE CT ; imaging ; CT ; CT ANGIOGRAPHY ; ANGIOGRAPHY ; arteries
    Type of Publication: Book chapter
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  • 2
    Keywords: brain ; Germany ; MODEL ; MODELS ; PERFUSION ; imaging ; SYSTEM ; CONTRAST ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; NERVOUS-SYSTEM ; CEREBRAL-BLOOD-FLOW ; CENTRAL-NERVOUS-SYSTEM ; CONTRAST-ENHANCED MRI ; functional MRI ; ENHANCEMENT ; INVERSION ; ARTERIAL ; contrast-enhanced ; functional imaging ; ARTERIAL WATER ; ASL ; BALLOON MODEL ; BOLD-fMRI ; BRAIN PERFUSION ; dynamic contrast enhanced-MRI ; dynamic susceptibility contrast-MRI ; FMRI ; HIGH-SPATIAL-RESOLUTION ; OXYGEN-CONSUMPTION ; QUIPSS II
    Abstract: This review presents the basic principles of functional imaging of the central nervous system utilizing magnetic resonance imaging. The focus is set on visualization of different functional aspects of the brain and related pathologies. Additionally, clinical cases are presented to illustrate the applications of functional imaging techniques in the clinical setting. The relevant physics and physiology of contrast-enhanced and non-contrast-enhanced methods are discussed. The two main functional MR techniques requiring contrast-enhancement are dynamic T1 - and T2(*)-MRI to image perfusion. Based on different pharmacokinetic models of contrast enhancement diagnostic applications for neurology and radio-oncology are discussed. The functional non-contrast enhanced imaging techniques are based on "blood oxygenation level dependent (BOLD)-fMRI and arterial spin labeling (ASL) technique. They have gained clinical impact particularly in the fields of psychiatry and neurosurgery
    Type of Publication: Journal article published
    PubMed ID: 15871087
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  • 3
    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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  • 4
    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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  • 5
    Keywords: computed tomography ; ANGIOGRAPHY ; ABDOMINAL-AORTA ; Aorta ; Aortic pathologies ; COMPUTED-TOMOGRAPHY AN
    Abstract: Current imaging of the aorta saw an improvement in terms of diversity and quality in recent years. In addition to verifying and documenting a clinical suspicion, it provides the basis for establishing an indication, choosing a therapy (conservative, surgical, interventional), as well as therapy planning and follow-up. Besides B-mode and duplex sonography, as well as transesophageal echocardiography (TEE), contrast-enhanced cross-sectional imaging, computer tomography (CT), with the option for CT angiography (CTA), and magnetic resonance tomography (MRT), with the option for MR angiography (MRA), play a significant role. The present article describes the possibilities offered by CTA and MRA for the diagnosis of aortic pathologies from the point of view of the radiologist in a maximum care hospital
    Type of Publication: Journal article published
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  • 6
    Keywords: Germany ; chest ; CT ; SYSTEM ; TOOL ; DEATH ; DISEASE ; MORTALITY ; RISK ; SURGERY ; PATIENT ; INJURIES ; MECHANISM ; IMPACT ; CONTRAST ; mechanisms ; treatment ; EXPERIENCE ; DISRUPTION ; REPAIR ; REGION ; ANGIOGRAPHY ; MANAGEMENT ; THORACIC AORTA ; HEIGHT ; wound ; STABILIZATION ; endovascular ; Cause of Death ; BLUNT ; DELAYED TREATMENT ; intracranial ; RUPTURE
    Abstract: Acute traumatic aortic tear (ATAT) is the second most common cause of deaths in trauma patients (about 8,000 deaths/year in the USA). Due to circumferential aortic disruption, up to 90% die at the scene. Responsible trauma mechanisms are: penetrating (gunshot/stab wounds), iatrogenic (interventional catheterization) and, most frequently, blunt chest trauma (high-speed motor vehicles, falls from heights, crushes, explosions) resulting in injury at the aortic isthmus region (loco typico, about 90%). Severe multiple system injuries (polytrauma), especially to intracranial and intraabdominal organs, are characteristic and prognostically predicitive. Immediate transthoracic open repair of ATAT has a mortality risk of 8% to 33% and paraplegia risk of 2% to 26%. Contrast enhanced CT scan has replaced the classical angiography as the diagnostic tool of choice. Patients with life-threatening multisystem injuries are scheduled for delayed repair after initial stabilization. Currently, the use of endovascular stent-grafts (EVAR) is being investigated. Our personal series confirms that EVAR for ATAT is a viable alternative to open repair while minimizing the morbidity and mortality of the open procedure and having a limited impact on trauma destabilization. The assessment of long-term durability of EVAR is one of the key issues to consider EVAR as the first choice of treatment
    Type of Publication: Journal article published
    PubMed ID: 16533692
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  • 7
    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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  • 8
    Keywords: MODEL ; VISUALIZATION ; DISEASE ; BLOOD-FLOW ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; SURVEILLANCE ; ANGIOGRAPHY ; endovascular repair ; endovascular ; ANEURYSM REPAIR ; Aorta ; stent graft ; phase-contrast flow ; blood flow velocity
    Abstract: PURPOSE: To validate flow measurements within an aortic nickel-titanium (nitinol) stent graft using velocity-encoded cine magnetic resonance imaging (VEC MRI) and to assess intraobserver agreement of repeated flow measurements. MATERIALS AND METHODS: An elastic tube phantom mimicking the descending aorta was developed with the possibility to insert an aortic nitinol stent graft. Different flow patterns (constant, sinusoidal and pulsatile aortic flow) were applied by a gear pump. A two-dimensional phase-contrast sequence was used to acquire VEC perpendicular cross-sections at six equidistant levels along the phantom. Each acquisition was performed twice with and without stent graft, and each dataset was analysed twice by the same reader. The percental difference of the measured flow volume to the gold standard (pump setting) was defined as the parameter for accuracy. Furthermore, the intraobserver agreement was assessed. RESULTS: Mean accuracy of flow volume measurements was -0.45+/- 1.63% without stent graft and -0.18+/- 1.45% with stent graft. Slightly lower accuracy was obtained for aortic flow both without (-2.31%) and with (-1.29%) stent graft. Accuracy was neither influenced by the measurement position nor by repeated acquisitions. There was significant intraobserver agreement with an intraclass correlation coefficient of 0.87 (without stent graft, p〈0.001) and 0.80 (with stent graft, p〈0.001). The coefficient of variance was 0.25% without stent graft and 0.28% with stent graft. CONCLUSION: This study demonstrated high accuracy and excellent intraobserver agreement of flow measurements within an aortic nitinol stent graft using VEC MRI. VEC MRI may give new insights into the haemodynamic consequences of endovascular aortic repair.
    Type of Publication: Journal article published
    PubMed ID: 20888719
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  • 9
    Keywords: POPULATION ; magnetic resonance imaging ; AGE ; NECK ; COMPUTED-TOMOGRAPHY ; ANGIOGRAPHY ; physiology ; CONFORMATIONAL-CHANGES ; THORACIC AORTA ; endovascular repair ; endovascular ; ANEURYSMS ; stent graft ; ARTERIAL STIFFNESS ; WAVE REFLECTION
    Abstract: PURPOSE: To test our hypothesis that distension and displacement in various segments of the healthy thoracic aorta are significant and can be predicted based on clinical characteristics. MATERIALS AND METHODS: Sixty-one Caucasian volunteers without cardiovascular disease (49 +/- 16 years, range 19-82; 28 men, 33 women) divided into two age groups (A: 〈50, B: 〉/= 50 years) underwent 1.5-T MRI. ECG-gated dynamic data sets were acquired at five locations perpendicular to the thoracic aorta. Aortic distension and Centre of Mass (CoM) displacement were determined as percentages of diastolic aortic diameter. A multiple linear regression model including age group, gender, location, mean arterial blood pressure, heart rate and body mass index was tested. RESULTS: Mean aortic distension averaged over all locations was 11.2 +/- 4.1% (age group A) and 6.7 +/- 3.3% (age group B), mean displacement 15.1 +/- 8.3% (A) and 11.0 +/- 6.2% (B). Systolic and diastolic aortic diameter and CoM position significantly differed at all locations (p〈0.001). Distension and displacement could be predicted based on the regression model (p〈0.001). Age group A and women exhibited significantly greater distension and displacement compared to age group B (p〈0.001) and men (p〈0.01), respectively. Distension increased, displacement decreased from proximal to distal. CONCLUSION: Distension and translational displacement are significant at all levels of the thoracic aorta and can be predicted based on clinical characteristics.
    Type of Publication: Journal article published
    PubMed ID: 20850234
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  • 10
    Keywords: brain ; Germany ; PERFUSION ; imaging ; CONTRAST ; CONTRAST AGENT ; MR ; EXPERIENCE ; CENTRAL-NERVOUS-SYSTEM ; intravenous ; CEREBRAL ARTERIOVENOUS-MALFORMATIONS ; CONTRAST AGENTS ; DOUBLE-BLIND ; GADOBENATE-DIMEGLUMINE ; GADODIAMIDE INJECTION ; GADOPENTETATE DIMEGLUMINE ; INTRACRANIAL METASTASES ; MAGNETIC-RESONANCE ANGIOGRAPHY ; MR-ANGIOGRAPHY ; F ; AGENT ; BILE
    Type of Publication: Journal article published
    PubMed ID: 15503381
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