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    Keywords: COMBINATION ; evaluation ; ALGORITHM ; VOLUME ; ACCURACY ; SURGERY ; TIME ; PATIENT ; DONOR ; intraoperative ; BODY-WEIGHT ; MR ; FIELD ; MAGNETIC-RESONANCE ; DISPLAY ; arteries ; MR-ANGIOGRAPHY ; magnetic resonance angiography ; ANOMALIES ; contrast-enhanced magnetic resonance angiography ; CT ANGIOGRAPHY ; DIGITAL SUBTRACTION ANGIOGRAPHY ; DIGITAL-SUBTRACTION-ANGIOGRAPHY ; gadobenate dimeglumine ; KIDNEY DONORS ; maximum intensity projection ; MAXIMUM-INTENSITY-PROJECTION ; pathology ; renal angiography ; shaded-surface display ; TRANSPLANT DONORS ; UROGRAPHY ; volume rendering
    Abstract: The aim of this study was to assess the value of contrast- enhanced three-dimensional MR angiography (CE 3D MRA) in the preoperative assessment of potential living renal donors, and to compare the accuracy for the depiction of the vascular anatomy using three different rendering algorithms. Twenty- three potential living renal donors were examined with CE 3D MRA (TE/TR=1.3 ms/3.7 ms, field of view 260-320x350 mm, 384- 448x512 matrix, slab thickness 9.4 cm, 72 partitions, section thickness 1.3 rum, scan time 24 s, 0.1 mmol/kg body weight gadobenate dimeglumine). Magnetic resonance angiography data sets were processed with maximum intensity projection (MIP), volume rendering (VR), and shaded-surface display (SSD) algorithms. The image analysis was performed independently by three MR-experienced radiologists recording the number of renal arteries, the presence of early branching or vascular pathology. The combination of digital subtraction angiography (DSA) and intraoperative findings served as the gold standard for the image analysis. In total, 52 renal arteries were correspondingly observed in 23 patients at DSA and surgery. Other findings were 3 cases of early branching of the renal arteries, 4 cases of arterial stenosis and I case of bilateral fibromuscular dysplasia. With MRA source data all 52 renal arteries were correctly identified by all readers, compared with 51 (98.1%), 51-52 (98.1-100%) and 49-50 renal arteries (94.2-96.2%) with the MIP, VR and SSD projections, respectively. Similarly, the sensitivity, specificity and accuracy was highest with the MRA source data followed by MIP, VR and SSD. Time requirements were lowest for the MIP reconstructions and highest for the VR reconstructions. Contrast-enhanced 3D MRA is a reliable, non-invasive tool for the preoperative evaluation of potential living renal donors. Maximum intensity projection is favourable for the processing of 3D MRA data, as it has minimal time and computational requirements, while having similar or superior accuracy for the depiction of vessel anomalies or pathology compared with VR and SSD, respectively
    Type of Publication: Journal article published
    PubMed ID: 12664119
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  • 3
    Keywords: evaluation ; Germany ; LUNG ; chest ; CT ; FOLLOW-UP ; follow-up studies ; IMAGES ; SUPPORT ; VENTILATION ; VOLUME ; RESOLUTION ; PATIENT ; MRI ; helium ; HEALTHY ; HYPERPOLARIZED HE-3 ; motion correction ; MR imaging ; PULMONARY ; VOLUMES ; RECIPIENTS ; BRONCHIOLITIS ; bronchiolitis obliterans ; lung transplantation ; pulmonary function ; PULMONARY-FUNCTION ; TRANSPLANT RECIPIENTS
    Abstract: The aim of this study was to evaluate the possible contribution of He-3-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up He-3-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At He-3-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and He-3-MRI was good, although subjective evaluation of He-3-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The He-3-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by He-3-MRI. In 2 of these 5 cases, He-3-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that He-3-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies
    Type of Publication: Journal article published
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  • 4
    Keywords: evaluation ; Germany ; THERAPY ; CLASSIFICATION ; CT ; DIAGNOSIS ; FOLLOW-UP ; imaging ; SPIRAL CT ; DISEASE ; NEW-YORK ; RISK ; computed tomography ; BLOOD-FLOW ; primary ; RISK-FACTORS ; MR ; MRI ; treatment ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; risk factors ; RISK FACTOR ; tomography ; SCINTIGRAPHY ; COMPUTED-TOMOGRAPHY ; ORGANIZATION ; BREATH-HOLD TECHNIQUE ; MR imaging ; HELICAL CT ; DIFFERENTIAL-DIAGNOSIS ; ARTERIAL-HYPERTENSION ; LEFT-VENTRICULAR DYSFUNCTION ; CHEST-X-RAY ; CHRONIC THROMBOEMBOLISM ; pulmonary hypertension,computed tomography,magnetic resonance imaging,echocardiography,angiography,E ; RADIOLOGIC FEATURES
    Abstract: In the recent World Health Organization (WHO) classification the group of pulmonary arterial hypertension (PH) comprises the classic primary pulmonary hypertension and several conditions with definite or very high risk factors to develop pulmonary arterial hypertension. Therapeutic advances drive the need for a comprehensive pre-therapeutic evaluation for optimal treatment. Furthermore, follow-up examinations need to be performed to monitor changes in disease status and response to therapy. Up to now, the diagnostic imaging work-up of PH comprises mainly echocardiography, invasive right heart catheterization and ventilation/perfusion scintigraphy. Due to technical advances helical computed tomography (CT) and magnetic resonance imaging (MRI) became more important in the evaluation and for differential diagnosis of pulmonary arterial hypertension. Both modalities are reviewed and recommendations for clinical use are given
    Type of Publication: Journal article published
    PubMed ID: 14740163
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  • 5
    Keywords: CANCER ; tumor ; carcinoma ; Germany ; LUNG ; PERFUSION ; THERAPY ; CT ; DENSITY ; LUNG-CANCER ; NEW-YORK ; TUMORS ; PATIENT ; CONTRAST ; INJECTION ; treatment ; DIFFERENCE ; REGION ; REGIONS ; LOCALIZATION ; PARAMETERS ; tomography ; CARCINOMAS ; COMPUTED-TOMOGRAPHY ; PET ; lung neoplasms ; PULMONARY ; DYNAMIC CT ; X-ray computed
    Abstract: Advanced bronchial carcinomas by means of perfusion and peak enhancement using dynamic contrast-enhanced multislice CT are characterized. Twenty-four patients with advanced bronchial carcinoma were examined. During breathhold, after injection of a contrast-medium (CM), 25 scans were performed (I scan/s) at a fixed table position. Density-time curves were evaluated from regions of interest of the whole tumor and high- and low-enhancing tumor areas. Perfusion and peak enhancement were calculated using the maximum-slope method of Miles and compared with size, localization (central or peripheral) and histology. Perfusion of large tumors (〉50 cm(3)) averaged over both the whole tumor (P=0.001) and the highest enhancing area (P=0.003) was significantly lower than that of smaller ones. Independent of size, central carcinomas had a significantly (P=0.04) lower perfusion (mean 27.9 ml/min/100 g) than peripheral ones (mean 66.5 ml/min/100 9). In contrast, peak enhancement of central and peripheral carcinomas was not significantly different. Between non-small-cell lung cancers and small-cell lung cancers, no significant differences were observed in both parameters. In seven tumors, density increase after CM administration started earlier than in the aorta, indicating considerable blood supply from pulmonary vessels. Tumor perfusion was dependent on tumor size and localization, but not on histology. Furthermore, perfusion CT disclosed blood supply from both pulmonary and/or bronchial vessels in some tumors
    Type of Publication: Journal article published
    PubMed ID: 15029450
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  • 6
    Keywords: CANCER ; tumor ; carcinoma ; Germany ; MICROVESSEL DENSITY ; MODEL ; PROSTATE ; THERAPY ; imaging ; INFORMATION ; NEW-YORK ; DIFFERENTIATION ; MONOCLONAL-ANTIBODY ; TISSUE ; TUMORS ; TIME ; PATIENT ; prognosis ; CONTRAST ; MR ; MRI ; ASSOCIATION ; SIGNAL ; antibodies ; antibody ; PROSTATE-CANCER ; RECURRENCE ; EXCHANGE ; PARAMETERS ; MONOCLONAL-ANTIBODIES ; adenocarcinoma ; intravenous ; prostate carcinoma ; TUMOR ANGIOGENESIS ; MR imaging ; GRADE ; RADICAL PROSTATECTOMY ; PATHOLOGICAL STAGE ; prostate carcinoma,dynamic contrast-enhanced MR imaging angiogenesis,microvessel density
    Abstract: The aim of this study was to correlate quantitative dynamic contrast-enhanced MRI (DCE MRI) parameters with microvessel density (MVD) in prostate carcinoma. Twenty-eight patients with biopsy-proven prostate carcinoma were examined by endorectal MRI including multiplanar T2- and T1-weighted spin-echo and dynamic T1-weighted turbo-FLASH MRI during and after intravenous Gd-DTPA administration. Microvessels were stained on surgical specimens using a CD31 monoclonal antibody. The MVD was quantified in hot spots by counting (MVC) and determining the area fraction by morphometry (MVAF). The DCE MRI data were analyzed using an open pharmacokinetic two-compartment model. In corresponding anatomic locations the time shift (Deltat) between the beginning of signal enhancement of cancer and adjacent normal prostatic tissue, the degree of contrast enhancement and the contrast exchange rate constant (k(21)) were calculated. The MVC and MVAF were elevated in carcinoma (p〈0.001 and p=0.002, respectively) and correlated to k(21) (r=0.62, p〈0.001 and r=0.80, p〈0.001, respectively). k(21)-values of carcinoma were significantly higher compared with normal peripheral but not central zone tissue. Deltat was longer in high compared with low-grade tumors (p=0.025). The DCE MRI can provide important information about individual MVD in prostate cancer, which may be helpful for guiding biopsy and assessing individual prognosis
    Type of Publication: Journal article published
    PubMed ID: 14531000
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  • 7
    Keywords: radiotherapy ; SURVIVAL ; Germany ; THERAPY ; FOLLOW-UP ; VOLUME ; NEW-YORK ; radiation ; PATIENT ; CONTRAST ; MR ; MRI ; treatment ; stereotactic ; stereotactic radiotherapy ; RADIATION-THERAPY ; RATES ; PROGNOSTIC FACTORS ; RANDOMIZED TRIAL ; ONCOLOGY-GROUP ; POSTOPERATIVE RADIOTHERAPY ; ADULTS ; BRAIN-TUMORS ; CONTRAST ENHANCEMENT ; GLIOMA ; GRADE ; LOW-GRADE ASTROCYTOMA ; astrocytoma,MRI,prognosticator,stereotactic radiotherapy
    Abstract: Aim of this study was to evaluate the role of pre-therapeutic and follow-up MRI in the clinical treatment and outcome in patients with astrocytoma WHO grade II after fractionated stereotactic radiation therapy (FSRT). One hundred thirty-nine patients with histologically proven astrocytoma WHO grade II were treated with FSRT and retrospectively evaluated. All patients had follow-up MRI studies (Gd-DTPA-enhanced T1- and T2-weighted MR images). Progression-free survival (PFS) and overall survival (OS) rates were calculated using the Kaplan-Meier method. Multivariate analysis was performed on five potential MRI related prognosticators. Median follow-up was 3.8 years. Positive contrast enhancement (CM+) prior to FSRT proved to be a significant prognosticator for PFS and OS (p〈0.01). Pre-therapeutic oedema on T2-weighted images and multifocality of contrast medium (CM) enhancement did not prove to be significant prognosticators. Also, diameter and volume of CM enhancement showed no significance on clinical outcome. Negative contrast enhancing (CM-) patients developing a de novo CM enhancement during follow-up showed a significantly worse clinical outcome compared with generally CM- patients (p〈0.05). Pre-therapeutic CM enhancement and the development of CM-enhancing areas during follow-up are negative prognosticators for PFS and OS. They must be interpreted as signs of secondary malignity
    Type of Publication: Journal article published
    PubMed ID: 14610685
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  • 8
    Keywords: measurement ; tumor ; Germany ; LUNG ; CT ; IMAGES ; DISEASE ; NEW-YORK ; TUMORS ; PATIENT ; REDUCTION ; CONTRAST ; MRI ; CYCLE ; SEQUENCE ; NO ; DIFFERENCE ; REGION ; LOCALIZATION ; LENGTH ; COMPUTED-TOMOGRAPHY ; CURVES ; 3-DIMENSIONAL RECONSTRUCTION ; MOTION ; HEALTHY ; ORIENTATION ; LOCATION ; dynamic MRI ; ADULT ; ADULTS ; STRENGTH ; TRUEFISP ; HEALTHY-VOLUNTEERS ; PULMONARY-FUNCTION ; HEART-FAILURE ; EXPIRATION ; LUNG-VOLUMES ; breathing cycle ; diaphragmatic function
    Abstract: The purpose of this study was to assess diaphragmatic length and shortening during the breathing cycle in healthy volunteers and patients with a lung tumor using dynamic MRI (dMRI). In 15 healthy volunteers and 28 patients with a solitary lung tumor, diaphragmatic motion and length were measured during the breathing cycle using a trueFISP sequence (three images per second in the coronal and sagittal plane). Time-distance curves and maximal length reduction (= shortening) of the diaphragm were calculated. The influence of tumor localization on diaphragmatic shortening was examined. In healthy volunteers maximal diaphragmatic shortening was 30% in the coronal and 34% in the sagittal orientation, with no difference between both hemithoraces. Tumors of the upper and middle lung region did not affect diaphragmatic shortening. In contrast, tumors of the lower lung region changed shortening significantly (P〈0.05). In hemithoraces with a tumor in the lower region, shortening was 18% in the coronal and 19% in the sagittal plane. The ratio of diaphragmatic length change from inspiration to expiration changed significantly from healthy subjects (inspiration length &MGT; expiratory length, P〈0.05) to patients with a tumor in the lower lung region (inspiratory length = expiratory length). dMRI is a simple, non-invasive method to evaluate diaphragmatic motion and shortening in volunteers and patients during the breathing cycle. Tumors of the lower lung region have a significant influence on shortening of the diaphragm
    Type of Publication: Journal article published
    PubMed ID: 15127220
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  • 9
    Keywords: GROWTH ; radiotherapy ; tumor ; Germany ; PERFUSION ; CT ; FOLLOW-UP ; HEPATOCELLULAR-CARCINOMA ; liver ; TISSUE ; TUMORS ; PATIENT ; BLOOD-FLOW ; RADIATION-THERAPY ; metastases ; tomography ; COMPUTED-TOMOGRAPHY ; LIVER METASTASES ; contrast media ; APPEARANCE ; ultrasound ; RE ; TUMOR-GROWTH ; monitoring ; ENHANCEMENT ; MICROBUBBLE CONTRAST ; TUMOR PERFUSION ; ARTERIAL ; PHASE ; SIZE ; contrast-enhanced ; ARTERIAL PHASE ; KUPFFER CELLS ; liver neoplasms
    Abstract: The purpose of this study was to monitor liver metastases after radiotherapy using contrast-enhanced ultrasound (CEUS). In 15 patients, follow-up examinations after stereotactic, single-dose radiotherapy were performed using CEUS (low mechanical index (MI), 2.4-ml SonoVue) and computed tomography (CT). Besides tumor size, the enhancement of the liver and the metastases was assessed at the arterial, portal venous, and delayed phases. The sizes of the tumor and of a perifocal liver reaction after radiotherapy measured with CEUS significantly correlated with those measured at CT (r=0.93, p〈0.001). CEUS found a significant reduction of the arterial vascularization in treated tumors (p〈0.05). In the arterial phase, the perifocal liver tissue was hypervascularized compared to the treated tumor (p〈0.001); in the late phase, it was less enhanced than the liver (p〈0.001) and more than the tumor (p〈0.01). The perifocal liver reaction was also seen in CT, but with a variable enhancement at the arterial (50% hyperdense compared to normal liver tissue), venous, or delayed phase (each with 70% hyperdense reactions). CEUS allows for the assessment of tumor and liver perfusion, in addition to morphological tumor examination, which was comparable with CT. Thus, changes of tumor perfusion, which may indicate tumor response, as well as the perifocal liver reaction after radiotherapy, which must be differentiated from perifocal tumor growth, can be sensitively visualized using CEUS
    Type of Publication: Journal article published
    PubMed ID: 15729565
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  • 10
    Keywords: AGE, ALGORITHM, ANGIOGRAPHY, Aorta, arterial wall motion, BLOOD, CONTOUR MODEL, CT, CT ANGIOGRAPHY,
    Abstract: Aortic distensibility is a parameter to grade vascular diseases and age-related effects because it is related to the elastic properties of the vessel wall. In this study vascular cross-sectional area changes have been determined using ECG-gated CT to analyse the age dependency of aortic distensibility. Distensibility measurements of the aorta were performed in 31 subjects (28 to 85 years). Time-resolved images were acquired either with a 4- or 16-detector row CT system using a modified CT angiography protocol. Cross-sectional area changes of the aorta were calculated by semiautomatic segmentation, and distensibility values were obtained using additional systemic blood pressure measurements. The aorta could be segmented successfully in all subjects. A decrease of aortic distensibility with age was found (r=0.50). Below (above) the renal arteries, the annual decrease was Delta D (infrarenal) =(- 2.1 +/- 0.7).10(-7)Pa(-1) a(-1), (D (suprarenal) Delta=(-3.5 +/- 1.1).10(-7) Pa-1 a(-1)). Differences between the ages, the youngest third and oldest third studied, were found to be significant ( (suprarenal)=0.003; P (infrarenal) =0.025). An age-dependent decrease of aortic wall elasticity can be determined in a modified routine CT angiography study
    Type of Publication: Journal article published
    PubMed ID: 16741718
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