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  • 1
    Keywords: radiotherapy ; Germany ; IN-VIVO ; imaging ; NEW-YORK ; PATIENT ; tumour ; MR ; MRI ; treatment ; SIGNAL ; PROTON ; SPECTROSCOPY ; stereotactic ; stereotactic radiotherapy ; DECREASE ; EFFICACY ; MAGNETIC-RESONANCE SPECTROSCOPY ; chemotherapy ; LINE ; positron emission tomography ; POSITRON-EMISSION-TOMOGRAPHY ; tomography ; PET ; INJURY ; GLIOMA ; proton magnetic resonance spectroscopy,magnetic resonance spectroscopic imaging chemotherapy,PCV,bra
    Abstract: Since antineoplastic activity varies, sensitive methods for individual assessment of efficacy are needed. We demonstrate the clinical value of MR spectroscopy in monitoring chemotherapy in a patient with recurrent glioma after stereotactic radiotherapy. Diagnostic imaging before and after chemotherapy included contrast-enhanced MRI, single-voxel proton MR spectroscopy (H-1 MRS), H-1 MR spectroscopic imaging (H-1 SI), and fluorodeoxyglucose (FDG) positron-emission tomography (PET). A significant decrease in choline signal intensity was observed 2 months after chemotherapy indicating tumour chemosensitivity, in line with tumour shrinkage on MRI and decreased uptake of FDG. Assessment of early response by MRS may help to improve treatment protocols in other patients
    Type of Publication: Journal article published
    PubMed ID: 14685797
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  • 2
    Keywords: SPECTRA ; human ; IN-VIVO ; VIVO ; IMAGES ; imaging ; INFORMATION ; METABOLISM ; DIFFERENTIATION ; TISSUE ; MARKER ; REDUCTION ; SIGNAL ; MAGNETIC-RESONANCE-SPECTROSCOPY ; STAGE ; PATTERNS ; NMR ; MARKERS ; PCR ; DAMAGE ; REGION ; REGIONS ; LOCALIZATION ; MUSCLE ; PARAMETERS ; SKELETAL-MUSCLE ; ATROPHY ; FEASIBILITY ; INFILTRATION ; LEVEL ; in vivo ; SIGNALS ; ACCESS ; H1 ; ADJACENT ; NECROSIS ; DEGENERATION ; atrophic muscle ; DENERVATION ; H-1 spectroscopy ; HUMAN-CALF-MUSCLE ; P-31 spectroscopic imaging ; REINNERVATION
    Abstract: Introduction The purpose of this feasibility study was to demonstrate non-invasive metabolic imaging of human muscular atrophy using significant changes of NMR signals that are related directly or indirectly to fiber necrosis. Methods Single-voxel H-1 NMR spectroscopy and two-dimensional P-31 spectroscopic imaging on a 1.5-T whole-body scanner were used for in vivo mapping of areas of muscle damage in two cases of differently localized and pronounced atrophy. Spectral patterns affiliated with severe and intermediate stages of degeneration were compared to data of healthy control tissue to derive appropriate metabolic markers related to lipid infiltration or high-energy P-31 metabolism. Results Reliable detection of atrophic tissue was achieved by the following parameters: ( 1) liposclerotic turnover is related to a drastic reduction in the water/lipid H-1 signal intensity ratio ( up to a factor of 74 compared to adjacent healthy tissue); ( 2) the P-31 resonance of phosphocreatine (PCr) is an adequate marker for differentiation of intact myocells with high-energy metabolism from regions dominated by terminal fiber necrosis ( PCr signal vanished nearly completely or intensity was reduced by a factor of 3 in affected muscles). Metabolic images based on this signal allowed accurate non-invasive localization of atrophic tissue. Conclusion The molecular information provided by NMR spectroscopy - previously only used with poor localization in atrophy studies - enables access to both the myocell-specific high-energy metabolism and the result of lipid infiltration allowing non-invasive mapping of degenerate tissue. The ability to investigate the results of these advanced levels of atrophy would also be useful for studies of more subtle degrees of denervation
    Type of Publication: Journal article published
    PubMed ID: 17031631
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  • 3
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    Neuroradiology 23 (5), 525-534 
    Keywords: advanced MRT, CNS, tumor
    Type of Publication: Journal article published
    PubMed ID: 24148674
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  • 4
  • 5
    Keywords: brain ; tumor ; AGENTS ; BLOOD ; Germany ; PERFUSION ; IMAGES ; imaging ; DISEASE ; DISEASES ; PROTEIN ; PROTEINS ; TIME ; SERA ; QUALITY ; CONTRAST ; SUFFICIENT ; CONTRAST AGENT ; FLOW ; HIGH-RESOLUTION MEASUREMENT ; INJECTION ; MR ; MRI ; TRACER BOLUS PASSAGES ; SIGNAL ; ALZHEIMERS-DISEASE ; PERFORMANCE ; ACQUISITION ; DECREASE ; NUMBER ; LOW-GRADE ASTROCYTOMAS ; CONTRAST AGENTS ; GADOBENATE-DIMEGLUMINE ; gadobenate dimeglumine ; VESSELS ; AFFINITY ; BOLUS ; STROKE ; MAPS ; AGENT ; albumin ; SERUM ; serum albumin ; DISORDERS ; review ; BRAIN-TUMORS ; GLIOMA ; perfusion study ; Alzheimer's disease ; BLOOD-VESSELS ; CEREBRAL BLOOD-VOLUME ; ISCHEMIC-STROKE ; TRANSIT-TIME ; tumor imaging
    Abstract: Today there are several indications for cerebral perfusion MRI. The major indications routinely used in increasing numbers of imaging centers include cerebrovascular disease, tumor imaging and recently psychiatric disorders. Perfusion MRI is based on the injection of a gadolinium chelate and the rapid acquisition of images as the bolus of contrast agent passes through the blood vessels in the brain. The contrast agent causes a signal change; this signal change over time can be analysed to measure cerebral hemodynamics. The quality of brain perfusion studies is very dependent on the contrast agent used: a robust and strong signal decrease with a compact bolus is needed. MultiHance (gadobenate dimeglumine, Gd-BOPTA) is the first of a new class of paramagnetic MR contrast agents with a weak affinity for serum proteins. Due to the interaction of Gd-BOPTA with serum albumin, MultiHance presents with significantly higher T1- and T2-relaxivities enabling a sharper bolus profile. This article reviews the indications of perfusion MRI and the performance of MultiHance in MR perfusion of different diseases. Previous studies using perfusion MRI for a variety of purposes required the use of double dose of contrast agent to achieve a sufficiently large signal drop to enable the acquisition of a clear input function and the calculation of perfusion rCBV and rCBF maps of adequate quality. Recent studies with Multi-Hance suggest that only a single dose of this agent is needed to cause a signal drop of about 30% which is sufficient to allow the calculation of high quality rCBV and rCBF maps
    Type of Publication: Journal article published
    PubMed ID: 15645153
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  • 6
    Keywords: IRRADIATION ; radiotherapy ; Germany ; FOLLOW-UP ; imaging ; ACCURACY ; TIME ; PATIENT ; tumour ; CONTRAST ; MR ; MRI ; H-1 ; MAGNETIC-RESONANCE ; MAGNETIC-RESONANCE-SPECTROSCOPY ; MR spectroscopy ; PROTON ; spectroscopic imaging ; magnetic resonance imaging ; LESIONS ; EXPERIENCE ; RADIATION-THERAPY ; PROGNOSTIC-FACTORS ; sensitivity ; GLIOMAS ; POSTOPERATIVE RADIOTHERAPY ; STANDARD ; ADULTS ; BRAIN-TUMORS ; CONTRAST ENHANCEMENT ; GLIOMA ; astrocytoma ; brain tumour ; SI ; INTERVAL ; fractionated stereotactic radiotherapy ; GLIOBLASTOMA-MULTIFORME ; contrast-enhanced ; LOW-GRADE GLIOMAS
    Abstract: We evaluated the value of magnetic resonance imaging (MRI) and the additional benefit of proton MR spectroscopic imaging (H-1 SI) in patients with a new suspicious lesion after fractionated stereotactic radiotherapy (FSRT) of a glioma. Thirty-four patients with histologically proven astrocytoma WHO II-IV after treatment by FSRT and a new suspect lesion in the follow-up were included in this study. Data were analysed by three independent radiologists with different experience in H-1 SI: Data were verified by clinical follow-up (PT, progressive tumour; nPT, non-progressive tumour) and a kappa analysis was performed. Sensitivity and specificity of T-1 weighted (w) and T(2)w MRI was compared (imaging at radiotherapy and follow-up) using further follow-up controls as gold standard and the additional benefit of H-1 SI (imaging at follow-up) was calculated. Mean interval between last irradiation and detection of a suspicious lesion was 37 +/- 32 months. Time to clinical evaluation was 13 +/- 8 months. Interobserver agreement was significantly high in all analyses (kappa always 〉 0.8, P 〈 0.05). T(2)w imaging proved to be superior to contrast enhanced T(1)w imaging in sensitivity (87.5 vs 81.25%) and specificity (85.7 vs 57.1%). Solitary H-1 SI had similar results as T(2)w (sensitivity 87.5%, specificity 71.4%). Taking all techniques into account, all PT were correctly diagnosed. Radiologists' experience had no significant influence on correct interpretation of a suspicious lesion. We conclude that H-1 SI is helpful in characterising new suspicious lesions in irradiated gliomas, particularly if pre-MRI is not available for evaluating follow-up
    Type of Publication: Journal article published
    PubMed ID: 16142479
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  • 7
    Keywords: CANCER ; radiotherapy ; DISEASE ; DIFFERENTIATION ; TUMORS ; chemotherapy ; SQUAMOUS-CELL CARCINOMA ; TREATMENT RESPONSE ; VALUES ; EARLY PREDICTION
    Abstract: INTRODUCTION: Using the intravoxel incoherent motion (IVIM) model, diffusion-related coefficient (D) and perfusion-related parameter (f) can be measured. Here, we used IVIM imaging to characterize squamous cell carcinomas of head and neck (HNSCC) and evaluated its application in follow-up after nonsurgical organ preserving therapy. METHODS: Twenty-two patients with locally advanced HNSCC (clinical stage III to IVb) were examined before treatment using eight different b values (b = 0, 50, 100, 150, 200, 250, 700, 800 s/mm(2)). All patients were followed for at least 7.5 months after conclusion of therapy. In 16 of these patients, follow-up MRI was available. Using the IVIM approach, f and D were extracted using a bi-exponential fit. For comparison, ADC maps were calculated. RESULTS: The initial values of f before therapy were located between 5.9 % and 12.9 % (mean: 9.4 +/- 2.4 %) except for two outliers (f = 17.9 % and 18.2 %). These two patients exclusively displayed poor initial treatment response. Overall, high initial f (13.1 +/- 4.1 % vs. 9.1 +/- 2.4 %) and ADC (1.17 +/- 0.08 x 10(-3) mm(2)/s vs. 0.98 +/- 0.19 x 10(-3) mm(2)/s) were associated with poor short term outcome (n = 6) after 7.5 months follow-up. D values before treatment were 0.98 x 10(-3) +/- 0.18 mm(2)/s and ADC values were 1.03 x 10(-3) +/- 0.18 mm(2)/s. At follow-up, in all primary responders, D (69 +/- 52 %), f (65 +/- 46 %), and ADC (68 +/- 49%) increased. CONCLUSIONS: Our preliminary evaluation indicates that an initial high f may predict poor prognosis in HNSCC. In responders, a significant increase of all IVIM parameters after therapy was demonstrated.
    Type of Publication: Journal article published
    PubMed ID: 23417120
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  • 8
  • 9
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    Neuroradiology 48 (Supplement), 3-8 
    Keywords: OPTIMIZATION ; tumor ; AGENTS ; PERFUSION ; imaging ; PROTEIN ; TUMORS ; PATIENT ; CONTRAST ; CONTRAST AGENT ; MR ; LESIONS ; SELECTION ; CONTRAST AGENTS ; contrast media ; MR imaging ; ADULT ; ADULTS ; tumor imaging ; REQUIREMENT ; PROFILES ; COMPOUND ; pediatric ; Gd-BOPTA
    Abstract: The challenging and multiple goals and requirements of CNS tumor imaging require optimization of the CNS imaging protocols, including selection of the optimal contrast medium. There are several gadolinium compounds available for imaging the CNS, and all of these except the compound Gd-BOPTA have nearly identical profiles. The unique protein interaction of Gd-BOPTA results in double T1 and T2 relaxivity. This article summarizes the advantages of Gd-BOPTA over conventional gadolinium compounds in both conventional and functional MR imaging. The results of recent studies in adults and pediatric patients are presented and discussed. The principal conclusion of this article is that not all contrast agents approved for MR imaging of the CNS behave in the same way. The use of the high-relaxivity agent Gd-BOPTA for morphological and functional MR imaging allows improved detection and delineation of CNS lesions compared to conventional gadolinium agents. This not only permits more confident diagnoses, but also results in a substantially improved differential diagnostic process. The higher relaxivity of Gd-BOPTA helps to optimize functional MR imaging studies e.g. perfusion MR imaging and other dynamic MR imaging protocols
    Type of Publication: Journal article published
    PubMed ID: 16699847
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  • 10
    Keywords: evaluation ; Germany ; IMAGES ; imaging ; DISEASE ; NEW-YORK ; NUCLEAR-MEDICINE ; TIME ; PATIENT ; QUALITY ; REDUCTION ; MRI ; SEQUENCE ; SEQUENCES ; magnetic resonance imaging ; NO ; ACQUISITION ; DIFFERENCE ; MOTION ; ABNORMALITIES ; SEGMENTS ; nuclear medicine ; DISC ; radiology ; IMAGING TECHNIQUES ; GRADE ; SPINE ; methods ; NUCLEAR ; IMAGE QUALITY ; NERVE ; technique ; parallel imaging ; SENSE ; USA ; GRAPPA ; AGREEMENT ; MEDICINE ; comparison ; neuroradiology ; degenerative lumbar spine disease
    Abstract: Introduction Parallel imaging techniques such as GRAPPA have been introduced to optimize image quality and acquisition time. For spinal imaging in a clinical setting no data exist on the equivalency of conventional and parallel imaging techniques. The purpose of this study was to determine whether T1- and T2-weighted GRAPPA sequences are equivalent to conventional sequences for the evaluation of degenerative lumbar spine disease in terms of image quality and artefacts. Methods In patients with clinically suspected degenerative lumbar spine disease two neuroradiologists independently compared sagittal GRAPPA (acceleration factor 2, time reduction approximately 50%) and non-GRAPPA images (25 patients) and transverse GRAPPA (acceleration factor 2, time reduction approximately 50%) and non-GRAPPA images (23 lumbar segments in six patients). Comparative analyses included the minimal diameter of the spinal canal, disc abnormalities, foraminal stenosis, facet joint degeneration, lateral recess, nerve root compression and osteochondrotic vertebral and endplate changes. Image inhomogeneity was evaluated by comparing the nonuniformity in the two techniques. Image quality was assessed by grading the delineation of pathoanatomical structures. Motion and aliasing artefacts were classified from grade 1 (severe) to grade 5 (absent). Results There was no significant difference between GRAPPA and non-accelerated MRI in the evaluation of degenerative lumbar spine disease (P 〉 0.05), and there was no difference in the delineation of pathoanatomical structures. For inhomogeneity there was a trend in favour of the conventional sequences. No significant artefacts were observed with either technique. Conclusion The GRAPPA technique can be used effectively to reduce scanning time in patients with degenerative lumbar spine disease while preserving image quality
    Type of Publication: Journal article published
    PubMed ID: 18274739
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