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  • 1
    Keywords: Germany ; QUANTIFICATION ; TIME ; PATIENT ; kidney ; BLOOD-FLOW ; CANINE MODEL ; intravascular contrast agent ; AGE ; MAGNETIC-RESONANCE ANGIOGRAPHY ; FEASIBILITY ; BREATH-HOLD ; GLOMERULAR-FILTRATION ; LEVEL ; LUMEN VISUALIZATION ; NONINVASIVE MEASUREMENT
    Abstract: Purpose: To prospectively assess feasibility of renal magnetic resonance (MR) perfusion measurement method based, on turbo fast low-angle shot sequences for grading effect of renal artery stenosis (RAS) on parenchymal perfusion. Materials and Methods: Institutional review board approved this study, and patients gave written consent. Seventy-three patients (34 male, 39 female; age range, 17-84 years) who were clinically suspected of having RAS underwent contrast material- enhanced (gadodiamide) saturation-recovery turbo fast low-angle shot imaging for measurement of renal perfusion and high-spatial-resolution MR angiograpby for RAS detection and grading. Degree of stenosis was evaluated as high grade (〉= 75% stenosis), low to intermediate grade (〉 0% to 〈 75% stenosis), or absent. High temporal resolution of the turbo fast low-angle shot sequence allowed acquisition of an exact first-pass tracing of the contrast agent bolus from which a signal intensity (SI)-time curve was derived. On the basis of this curve, mean transit time (MTT) of the contrast agent bolus, maximal upslope (MUS) of the curve, maximum SI, and time to SI peak (TTP) were calculated with a gamma variate fit. Wilcoxon rank sum test, Pearson product moment correlation, and paired t test were used for statistical analysis. Results: Twenty-four renal arteries had high-grade RAS, 12 renal arteries had low- to intermediate-grade RAS, and 104 renal arteries had no RAS. Significant differences between patients without stenoses or with low- to intermediate-grade stenoses and patients with high-grade stenoses were found for MTT, MUS, and TTP (P 〈.001). Perfusion parameters were correlated with patients' serum creatinine levels, and significant correlations were found for MTT (r = 0.41), MUS (r = 0.48), and TTP (r = 0.4), with P 〈.001. Conclusion: MR perfusion parameters can be used to assess effect of RAS on parenchymal perfusion. Perfusion measurements reflect renal function as measured with serum creatinine levels. (c) RSNA, 2006
    Type of Publication: Journal article published
    PubMed ID: 16436819
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  • 2
    Keywords: 3D MR-ANGIOGRAPHY, ANGIOGRAPHY, CHEST CT, COMMON, comparison, CONTRAST, CONTRAST-ENHANCED MR, contra
    Abstract: Pulmonary embolism (PE) is a very common and potentially life-threatening disease. In comparison with CT, the clinical relevance of magnetic resonance imaging (MRI) for the assessment of PE is low. Nevertheless, as there are some potential advantages of MRI over CT (e.g. radiation free method, better safety profile of MR contrast media, capability of functional imaging). In certain patient, groups MRI might therefore be considered as a valuable alternative in the assessment of suspected PE. This article reviews the relevant MRI techniques for the evaluation of PE and gives an overview of the current literature for contrast-enhanced MR angiography of PE
    Type of Publication: Journal article published
    PubMed ID: 17486344
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  • 3
    Keywords: AGENTS ; Germany ; imaging ; DISEASE ; MORTALITY ; NEW-YORK ; NUCLEAR-MEDICINE ; TIME ; PATIENT ; kidney ; CONTRAST ; CONTRAST AGENT ; ASSOCIATION ; PATHOGENESIS ; HIGH-RISK ; STABILITY ; CONTRAST AGENTS ; MAGNETIC-RESONANCE ANGIOGRAPHY ; magnetic resonance imaging (MRI) ; nuclear medicine ; AGENT ; radiology ; fibrosis ; case control study ; review ; ENHANCED MR-ANGIOGRAPHY ; case control studies ; NUCLEAR ; USA ; function ; RECOMMENDATIONS ; odds ratio ; retrospective ; systemic ; MEDICINE ; case control ; medical imaging ; - ; German ; case-control ; gadolinium ; OCCURS ; CONTRAST-MEDIA ; review article ; DERMOPATHY ; GADODIAMIDE ; HIGH-RISK PATIENTS ; NEPHROGENIC SYSTEMIC FIBROSIS ; nephrogenic systemic fibrosis (NSF) ; RATIO ; SUBTRACTION ; TRANSMETALATION
    Abstract: Nephrogenic systemic fibrosis (NSF) is a systemic disease with a 5% mortality which was first described in 1997 and which only occurs in patients with severely impaired renal function (GFR 〈 30 ml/min per 1.73 m(2)) and for which an association with previous administration of several Gd-chelates has been observed. According to retrospective case control studies the odds ratio for a patient with severely impaired renal function to develop NSF was increased by a factor of 22-32 when gadodiamide was administered. At this time there are approximately 250 confirmed cases of NSF of which 177 are associated with the administration of gadodiamide and 78 are associated with gadopentetate dimeglumine. This review article elucidates the postulated pathogenesis of NSF and provides an overview of the published statements and recommendations from international regulatory authorities and from international advisory boards. Even though the pathogenesis is not completely understood at this time, the European Pharmacovigilance Working Party has decided that gadodiamide and gadopentetate dimeglumine must not be used in high-risk patients. Other Gd-containing contrast agents should only be administered after thorough assessment of the indication and with minimized Gd dose. In the USA, the FDA has issued a black box warning for Gd-containing contrast agents
    Type of Publication: Journal article published
    PubMed ID: 17624507
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  • 4
    Keywords: DIAGNOSIS ; QUANTIFICATION ; INTEROBSERVER VARIABILITY ; CANINE MODEL ; MR-ANGIOGRAPHY ; magnetic resonance angiography ; DIGITAL-SUBTRACTION-ANGIOGRAPHY ; parenchymal disease ; renal artery stenosis ; RENOVASCULAR DISEASE ; vascular disease ; VASCULAR-DISEASE
    Type of Publication: Journal article published
    PubMed ID: 12808157
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  • 5
    Keywords: Germany ; IMAGES ; ACCURACY ; INTEROBSERVER VARIABILITY ; RESOLUTION ; PATIENT ; MAGNETIC-RESONANCE ; ACQUISITION ; AGE ; WOMEN ; MEN ; arteries ; MAGNETIC-RESONANCE ANGIOGRAPHY ; HYPERTENSION ; STANDARD ; SUBSET ; METAANALYSIS ; STENOSIS ; HIGH-SPATIAL-RESOLUTION ; RENAL-ARTERIES ; BALLOON ANGIOPLASTY ; INTRAVASCULAR ULTRASOUND
    Abstract: PURPOSE: To retrospectively compare three-dimensional gadolinium-enhanced magnetic resonance (MR) angiography, performed with an integrated parallel acquisition technique for high isotropic spatial resolution, with selective digital subtraction angiography (DSA) and intravascular ultrasonography (US) for accuracy of diameter and area measurements in renal artery stenosis. MATERIALS AND METHODS: The study was approved by the institutional review, board, and consent was obtained from all patients. Forty-five patients (17 women, 28 men; mean age, 62.2 years) were evaluated for suspected renal artery stenosis. Three-dimensional gadolinium-enhanced MR angiograms were acquired with isotropic spatial resolution of 0.8 X 0.8 X 0.9 mm in 23-second breath-hold with an integrated parallel acquisition technique. In-plane diameter of stenosis was measured along vessel axis, and, perpendicular diameter and area of stenosis were assessed in cross sections orthogonal to vessel axis, on multiplanar reformations. Interobserver agreement between two radiologists in measurements of in-plane and perpendicular diameters of stenosis and perpendicular area of stenosis was assessed with mean percentage of difference. In a subset of patients, degree of stenosis at MR angiography was compared with that at DSA (n = 20) and intravascular US (n = 11) by using Bland-Altman plots land correlation analyses. RESULTS: Mean percentage of difference in stenosis measurement was reduced from 39.3% +/- 78.4 (standard deviation) with use of in-plane views to 12.6% +/- 9.5 with use of cross-sectional views (P 〈.05). Interobserver agreement for stenosis, grading based on perpendicular area of stenosis was significantly better than that for stenosis grading based on in-plane diameter of stenosis (mean percentage of difference, 15.2% +/- 24.2 vs 54.9% +/- 186.9; P 〈.001). Measurements of perpendicular area of stenosis on MR angiograms correlated well with those on intravascular US images (r(2) = 0.90). CONCLUSION: Evaluation of cross-sectional images reconstructed from high-spatial-resolution three-dimensional gadolinium-enhanced MR renal angiographic data increases the accuracy of the technique and decreases interobserver variability. (C) RSNA, 2005
    Type of Publication: Journal article published
    PubMed ID: 15770035
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  • 6
    Keywords: ACCURACY ; CONTRAST ; CT ANGIOGRAPHY ; ANGIOGRAPHY ; BODY ; BODIES ; CHEST CT ; DEEP-VEIN THROMBOSIS ; devel
    Abstract: Recent technical developments have substantially improved the potential of MRI for the diagnosis of pulmonary embolism. On the MR scanner side this includes the development of short magnets and dedicated whole body MRI systems, which allow a comprehensive evaluation of pulmonary embolism and deep venous thrombosis in a single exam. The introduction of parallel imaging has substantially improved the spatial and temporal resolution of pulmonary MR angiography. By combining time-resolved pulmonary perfusion MRI with high-resolution pulmonary MRA a sensitivity and specificity of over 90% is achievable, which is comparable to the accuracy of CTA. Thus, for certain patient groups, such as patients with contraindications to iodinated contrast media and young women with a low clinical probability for pulmonary embolism, MRI can be considered as a first-line imaging tool for the assessment of pulmonary embolism
    Type of Publication: Journal article published
    PubMed ID: 17673970
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  • 7
    Keywords: Germany ; LUNG ; chest ; CT ; imaging ; VISUALIZATION ; CONTRAST ; MRI ; SEQUENCE ; SEQUENCES ; SIGNAL ; FIELD ; magnetic resonance imaging ; NO ; COMPUTED-TOMOGRAPHY ; pathology ; BREATH-HOLD TECHNIQUE ; HELICAL CT ; EX-VIVO ; HEALTHY-VOLUNTEERS ; CHEST-X-RAY ; CYSTIC-FIBROSIS ; methods ; NUCLEAR ; IMAGE QUALITY ; RECOVERY ; USA ; correlation ; PULMONARY NODULES ; lungs ; phantom ; comparison ; pulmonary nodule ; INITIAL-EXPERIENCE ; 3 T ; 3.0 T ; high-field ; pneumonia ; TURBO SPIN-ECHO
    Abstract: Objectives: To compare the image quality and lesion contrast of lung MRI using 5 different pulse sequences at 1.5 T and 3 T. Materials and Methods: Lung MRI was performed at 1.5 T and 3 T using 5 pulse sequences which have been previously proposed for lung MRI: 3D volumetric interpolated breath-hold examination (VIBE), true fast imaging with steady-state precession (TrueFISP), half-Fourier single-shot turbo spin-echo (HASTE), short tau inversion recovery (STIR), T-2-weighted turbo spin-echo (TSE). In addition to 4 healthy volunteers, 5 porcine lungs were examined in a dedicated chest phantom. Lung pathology (nodules and infiltrates) was simulated in the phantom by intrapulmonary and intrabronchial injections of agarose. CT was performed in the phantom for correlation. Image quality of the sequences was ranked in a side-by-side comparison by 3 blinded radiologists regarding the delineation of pulmonary and mediastinal anatomy, conspicuity of pulmonary nodules and infiltrates, and presence of artifacts. The contrast of nodules and infiltrates (C-NODULES and C-INFILTRATES) defined by the ratio of the signal intensities of the lesion and adjacent normal lung parenchyma was determined. Results: There were no relevant differences regarding the preference for the individual sequences between both field strengths. TSE was the preferred sequence for the visualization of the mediastinum at both field strengths. For the visualization of lung parenchyma the observers preferred TrueFISP in volunteers and TSE in the phantom studies. At both field strengths VIBE achieved the best rating for the depiction of nodules, whereas HASTE was rated best for the delineation of infiltrates. TrueFISP had the fewest artifacts in volunteers, whereas STIR showed the fewest artifacts in the phantom. For all but the TrueFISP sequence the lesion contrast increased from 1.5 T to 3 T. At both field strengths VIBE showed the highest C-NODULES (6.6 and 7.1) and HASTE the highest C-INFILTRATES (6.1 and 6.3). Conclusion: The imaging characteristics of different pulse sequences used for lung MRI do not substantially differ between 1.5 T and 3 T. A higher lesion contrast can be expected at 3 T
    Type of Publication: Journal article published
    PubMed ID: 17507808
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  • 8
    Keywords: Germany ; COMMON ; CT ; DIAGNOSIS ; FOLLOW-UP ; imaging ; DISEASE ; MORTALITY ; NEW-YORK ; ACCURACY ; computed tomography ; NUCLEAR-MEDICINE ; PATIENT ; REPAIR ; EFFICIENT ; tomography ; COMPUTED-TOMOGRAPHY ; sensitivity ; specificity ; CT ANGIOGRAPHY ; ANGIOGRAPHY ; ARTERY ; nuclear medicine ; DISSECTION ; radiology ; HIGH-RESOLUTION ; THORACIC AORTA ; MORBIDITY ; PRINCIPLES ; NUCLEAR ; USA ; aneurysm ; Aorta ; MEDICINE ; NOV ; medical imaging ; ANEURYSMS ; German ; aortic dissection ; aortic disease ; INTRAMURAL HEMATOMA ; MULTIDETECTOR-ROW CT ; multisclice computed tomography (MSCT)
    Abstract: Aortic disease is associated with high morbidity and mortality and thus require an efficient and accurate diagnostic approach, especially in the acute setting. Multislice computed tomography (MSCT) with the option of high-resolution CT angiography (CTA) has emerged as the standard of reference in diagnosis and follow-up of patients with acquired aortic disease. Aortic dissection is the most common aortic emergency, but it remains undiscovered in up to 38% of cases. Sensitivity and specificity of MSCT in the assessment of aortic dissection are greater than 99%. The sensitivity of CT in the detection of inflammatory changes is 83%; its specificity is almost 100%; and its diagnostic accuracy is ca. 94%. This article outlines state-of-the-art principles in diagnostic CT imaging of acquired aortic disease
    Type of Publication: Journal article published
    PubMed ID: 17938873
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  • 9
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    Radiologe 51 (1), 5-5 
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Psychosomatic Research 26 (1982), S. 77-81 
    ISSN: 0022-3999
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine , Psychology
    Type of Medium: Electronic Resource
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