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  • 1
    Electronic Resource
    Electronic Resource
    Study of nuclear effects in nucleon structure functions up to and beyond the kinematic limit (1986)
    Springer
    Czechoslovak journal of physics 36 (1986), S. 1288-1302 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An experiment on deep inelastic muon nucleon scattering in order to study the x-dependence of nucleon structure functions and their ratios over a range ofQ 2=50–200 GeV2 andx= =0·4–2·0 is proposed. Such measurements performed on a number of nuclei with atomic weights from 2 to 207 provide new information for detailed studies of the EMC effect and test models explaining thex-behaviour of the nucleon structure functions and their ratios. The measurements are decisive for the proof that a quark-parton model of the nucleus describes adequately nuclear structure probed at high energies. The upgraded high luminosity BCDMS spectrometer with improved resolution in transferred energyν can be used for the measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01598030
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  • 2
    Electronic Resource
    Electronic Resource
    Hepatic MR imaging: comparison of RARE derived sequences with conventional sequences for detection and characterization of focal liver lesions (1996)
    Springer
    Abdominal imaging 21 (1996), S. 427-432 
    Details
    ISSN: 1432-0509
    Keywords: Key words: MRI—Hepatic imaging—RARE—Detection—Characterization.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Background: We compared two T2-weighted turbo spin echo (TSE) sequences with a T2-weighted conventional SE (CSE) sequence to determine whether sequences derived from rapid acquisition with relaxation enhancement such as TSE could replace CSE for the detection and subsequent characterization of focal liver lesions. Methods: A total of 55 consecutive patients with 107 liver lesions underwent magnetic resonance imaging examinations at 1.5 Tesla, with a constant imaging protocol. TSE pulse sequences were acquired with eight echo trains (repetition time [TR], 4718 ms; echo time [TE], 90 ms; acquisition time [TA], 4.03 min; and a symmetric k-space ordering scheme) and 11 echo trains (TR, 4200 ms; TE, 140 ms; TA, 4.40 min; and an asymmetric k-space ordering scheme) and compared with CSE (TR, 2300 ms; TE, 45/90 ms; TA, 9.53 min). Images were analyzed qualitatively by scoring image quality and artifacts and counting focal liver lesions by independent reading with consensus obtained for discrepancies. Quantitative analysis was performed by measuring signal-to-noise (S/N), contrast-to-noise (C/N), and tumor–liver signal intensity (T/L) ratios. Results: T2-weighted TSE sequences provided better subjective image quality and reduced artifacts as compared with the T2-weighted CSE sequence. CSE and TSE sequences exhibited no statistically significant differences in liver S/N, lesion–liver C/N (CSE TE, 90 ms: 18.6 ± 14.0; TSE TE, 90 ms: 16.5 ± 12.9) and the detectability of focal liver lesions. Heavily T2-weighted TSE with a TE of 140 ms allowed correct characterization of focal liver lesions based on a T/L ratio of 3.0 in 84% of patients. Conclusions: T2-weighted TSE sequences are as suited as CSE for the detection (TE, 90 ms), and appear to be superior for the characterization (TE, 140 ms), of focal hepatic lesions. Whether a single sequence, such as a double-echo TSE or a single-echo TSE sequence with a TE between 110 and 120 ms, might perform both functions as well or better than CSE is unknown. However, because of time savings, TSE eventually may be preferred over CSE.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002619900097
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  • 3
    Electronic Resource
    Electronic Resource
    Book reviews (1996)
    Springer
    European radiology 6 (1996), S. 155-155 
    Details
    ISSN: 1432-1084
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00181134
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  • 4
    Electronic Resource
    Electronic Resource
    Study of susceptibility-induced artefacts in GRASE with different echo train length (1998)
    Springer
    European radiology 8 (1998), S. 834-838 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Magnetic resonance imaging ; Brain hemorrhage ; FSE ; GRASE ; Susceptibility artefact
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to evaluate the sensitivity of gradient-and-spin-echo (GRASE) sequences to susceptibility effects. GRASE sequences with 21 and 33 echoes per echo train were compared with a T2-weighted FSE sequence with an echo train length of 5 by means of MRI in phantoms, volunteers (n = 10), and patients (n = 19) with old hemorrhagic brain lesions. All experiments were performed on a 1.0-T clinical MR system (Impact Expert, Siemens AG, Erlangen, Germany) with constant imaging parameters. Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations, of brain areas with physiological iron deposition (red nucleus, substantia nigra), and of areas of old brain hemorrhage were calculated for FSE and GRASE pulse sequences. Areas of old brain hemorrhage were also qualitatively analyzed for the degree of visible susceptibility effects by blinded reading. The CNR of iron oxide tubes and iron-containing brain areas decreased with increasing echo trains of GRASE sequences. The CNR of GRASE sequences decreased when compared with CNR of their FSE counterparts (GRASE 21 echo trains 23.8 ± 0.8, FSE 5 echo trains 26.7 ± 0.9; p≤ 0.01). Qualitative analysis confirmed these measurements. FSE with an ETL of 5 demonstrated significantly stronger susceptibility effects than their GRASE counterpart with an ETL of 21. The results demonstrate that GRASE sequences do not necessarily compensate for the reduced sensitivity of FSE to susceptibility effects. The complex signal behavior of GRASE makes conventional SE, gradient echo, or FSE sequences containing shorter echo trains preferable when patients with intracranial hemorrhage are clinically evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050481
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  • 5
    Electronic Resource
    Electronic Resource
    Application of a stable cell culture assay for the functional assessment of novel MR contrast agents (1997)
    Springer
    European radiology 7 (1997), S. 527-531 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Cell culture ; Hepatocytes ; MR receptor agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this study was to apply a new cell culture assay that preserves hepatocyte orientation and differentiation for screening of MR contrast agents with hepatocyte specificity. Cultured hepatocytes were sandwiched between two layers of collagen, preserving both hepatocyte function and morphology over a prolonged period of time. Plain and rhodaminated monocrystalline iron-oxide particles (MION and MION-rh) and asialoglycoprotein receptor-specific rhodaminated asialofetuin coupled to MION (MION-ASF-rh) were prepared. Dose-dependent competition experiments of these agents were performed with D( + )-galactose to determine the specificity of galactose-mediated cell uptake. To assess the impact of cell integrity on cell uptake dose-dependent functional experiments with two hepatotoxins (ethanol and CCl4) were performed. Normal cell cultures showed significantly higher fluorescent-light emission after incubation with hepatocyte-directed ASF-MION-rh than after incubation with MION-rh. Competition experiments of ASF-MION with galactose showed a dose-dependent decrease in calibrated fluorescent-light emission. Cell cultures treated with hepatotoxins demonstrated a dose-dependent reduction in calibrated fluorescent-light emission following incubation with ASF-MION-rh. The validated assay system allows assessment not only of hepatocyte specificity, but also of hepatocyte damage. Because the assay can be applied to cells from any species (rat, pig, human), it may represent an ideal test system prior to clinical trials of new hepatocyte-directed MR contrast agents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050197
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  • 6
    Electronic Resource
    Electronic Resource
    Intracranial vascular stenosis and occlusion: comparison of 3D time-of-flight and 3D phase-contrast MR angiography (1998)
    Springer
    Neuroradiology 40 (1998), S. 567-573 
    Details
    ISSN: 1432-1920
    Keywords: Key words Intracranial blood vessels ; stenosis and occlusion ; Magnetic resonance angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We compared the value of 3D time-of-flight (TOF) and phase-contrast (PC) MR angiography (MRA) for detection and grading of intracranial vascular steno-occlusive disease. Unenhanced 3D-TOF MRA and 3D-PC MRA (30–60 cm/s velocity encoding) were performed at the level of the circle of Willis in 18 patients, mean age 56 ± 10 years. Postprocessed images using a maximum-intensity projection reconstruction with multiple targetted projections were analysed. A total of 126 vessels was assessed by PC MRA and 143 by TOF MRA, with digital subtraction angiography (DSA) in 15 patients and/or transcranial Doppler sonography (TCD) in 18 as a standard. Two blinded readers reviewed the MRA, DSA and TCD examinations retrospectively. On DSA and/or TCD the two observers found 32 and 28 steno-occlusive lesions. 3D-TOF MRA was more sensitive than 3D-PC MRA (87 % and 86 % vs. 65 % and 60 %) and had a higher negative predictive value (96 % vs. 89 %). Correct grading of stenoses was achieved in 78 % by 3D-TOF and 65 % by 3D-PC MRA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002340050645
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  • 7
    Electronic Resource
    Electronic Resource
    Neue MR-Kontrastmittel in der Leberdiagnostik Erste klinische Ergebnisse mit hepatobiliärem Eovist® (Gadolinium-EOB-DTPA) und RES-spezifischem Resovist® (SH U 555 A) (1996)
    Springer
    Der Radiologe 36 (1996), S. 124-133 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Leber ; MRT ; Kontrastmittel ; Resovist® ; Eovist® ; Key words Liver ; MRI ; Contrast agents ; Resovist ; Eovist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The purpose of this work is to describe our initial clinical experience (in 66 patients) with Resovist and Eovist, two new liver-specific MR contrast agents. We focus our report on safety aspects, dose finding, and optimization of technical parameters. Both contrast agents were well tolerated and improved the detectability of focal liver lesions. With Resovist, postcontrast MRI may be started as early as 10 min following injection. The dose of 8 μmol Fe/kg bodyweight was sufficient to achieve diagnostic tumor-liver contrast levels. Since Eovist can also be administered as a bolus, dynamic enhance- ment patterns may be studied for tumor characterization as well. Breath-hold T 1-weighted FLASH images were superior to other T 1-weighted techniques with and without fat saturation.
    Notes: Zusammenfassung In der vorliegenden Arbeit werden erste klinische Ergebnisse (66 Patienten) der für die Leberbildgebung entwickelten Kontrastmittel Resovist® und Eovist® vorgestellt. Es wurden Sicherheitsaspekte, Dosierungsfragen und die optimale Untersuchungstechnik am Beispiel fokaler Leberläsionen untersucht. Beide „leberspezifischen“ Kontrastmittel zeigten bei guter Verträglichkeit eine Verbesserung des Nachweises fokaler Leberläsionen. Die Untersuchung mit Resovist® kann bereits 10 min nach der Kontrastmittelinjektion erfolgen. Mit einer Dosis von 8 μmol Fe/kg Körpergewicht konnte eine ausreichender Tumor-Leber-Kontrast erzielt werden. Da Eovist® zusätzlich im Bolus injiziert werden kann, ergeben sich neben dem Nachweis fokaler Leberläsionen Möglichkeiten der Charakterisierung durch Analyse der Perfusionsmuster. Atemgehaltene T 1-gewichtete FLASH-Sequenzen waren sonstigen T 1-gewichteten Sequenzen ohne und mit Fettgesättigung überlegen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050049
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  • 8
    Electronic Resource
    Electronic Resource
    Hochdosierte Anwendung von Gd-DTPA-BMA (Gadodiamid) in der Diagnostik und Therapiebeurteilung maligner Knochentumoren (1996)
    Springer
    Der Radiologe 36 (1996), S. 148-152 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Gd-DTPA-BMA ; Magnetresonanztomographie ; Dynamische Studien ; Knochenläsionen ; Präoperative Chemotherapie ; Key words Gd-DTPA-BMA ; Magnetic resonance imaging ; Dynamic studies ; Bone lesions ; Preoperative chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: To evaluate the efficacy of high-dose Gd-DTPA-BMA (gadodiamide, Omniscan) as a contrast for magnetic resonance imaging of malignant bone tumors and the use of high-dose dynamic studies for predicting the response to preoperative chemotherapy. Materials and methods: Examinations were performed in 22 patients with suspected malignant bone tumor on a 1.5 T system. In 8 cases a follow-up examination was done after preoperative chemotherapy. Static studies included Pd- and T2-weighted spin-echo sequences as well as T1-weighted spin-echo sequences, obtained pre- and postcontrast. Dynamic studies were performed using a FLASH 2D-gradient-echo sequence (TR 40 ms/TE 10 ms, 90 ° flip angle) every 20 s after intravenous bolus injection of Gd-DTPA-BMA (0.3 mmol/kg body weight). MR images were evaluated qualitatively by visual assessment of conspicuity size, extraosseous delineation and structure of the lesion and quantitatively by measurement of the signal intensities and calculation of the relative increase in signal intensity. Results: Qualitative image analysis showed best demonstration of the lesions on contrast-enhanced T1-weighted images. Comparison of T1-weighted pre- and postcontrast spin-echo sequences revealed significantly better assessment of tumor structure after administration of contrast media. After preoperative chemotherapy, all responders showed a markedly stronger reduction in relative increase in signal intensity in dynamic studies compared to nonresponders. Conclusion: Gd-DTPA-BMA is effective for magnetic resonance imaging of musculoskeletal lesions and improves assessment of the tumor structure. Dynamic studies may help to predict the response to preoperative chemotherapy.
    Notes: Zusammenfassung Ziel der Studie: Untersucht wurde, ob die hochdosierte Gabe von Gd-DTPA-BMA (Gadodiamid, Omniscan™) sich für die kontrastmittelunterstützte Magnetresonanztomographie maligner Knochentumoren eignet und ob dynamische Studien bei dieser Dosis eine Beurteilung des Ansprechens auf eine präoperative Chemotherapie ermöglichen. Material und Methode: Die Untersuchungen erfolgten bei 22 Patienten mit Verdacht auf malignen Knochentumor bei einer Feldstärke von 1,5 Tesla. In 8 Fällen wurde eine Verlaufskontrolle nach präoperativer Chemotherapie durchgeführt. Die statischen Untersuchungen umfaßten PD- und T2-gewichtete Spinechosequenzen sowie T1-gewichtete Spinechosequenzen vor und nach Kontrastmittelapplikation. Dynamische Studien wurden mit einer FLASH-2D-Gradientenechosequenz (TR 40 ms/TE 10 ms, Flipwinkel 90 °) im Abstand von je 20 s nach intravenöser Bolusinjektion von Gd-DTPA-BMA (0,3 mmol/kg Körpergewicht) durchgeführt. Die Auswertung der MR-Bilder erfolgte qualitativ durch visuelle Beurteilung der Erkennbarkeit, der Größe, der extraossären Ausdehnung und der Struktur der Läsion und quantitativ mit Messung der Signalintensitäten und Berechnung des relativen Signalanstieges. Ergebnisse: Die qualitative Bildauswertung ergab für die T1-gewichteten Bilder nach Kontrastmittelapplikation die beste Erkennbarkeit der Läsion. Der Vergleich der T1-gewichteten Spinechosequenz vor und nach Kontrastmittelapplikation zeigte eine signifikant verbesserte Beurteilbarkeit der Tumorstruktur nach Kontrastmittelgabe. In den dynamischen Untersuchungen wiesen alle Responder nach präoperativer Chemotherapie einen deutlich stärkeren Abfall des relativen Signalintensitätsanstieges als die Nonresponder auf. Schlußfolgerung: Gd-DTPA-BMA ist ein effektives Kontrastmittel für die Magnetresonanztomographie muskuloskeletaler Läsionen und ermöglicht eine verbesserte Beurteilung der Tumorstruktur. Dynamische Studien können zur Beurteilung des Ansprechens der präoperativen Chemotherapie beitragen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050052
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  • 9
    Electronic Resource
    Electronic Resource
    Entwicklung und experimenteller Einsatz von rezeptorspezifischen MR-Kontrastmitteln (1996)
    Springer
    Der Radiologe 36 (1996), S. 153-163 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Rezeptoren ; Spezifische Aufnahme ; Funktion ; Key words Receptors ; Specific attachment ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The authors describe the feasibility of developing receptor-specific MR contrast agents for the improved detection of pathology and assessment of organ function. Receptor specificity of MR contrast agents can be achieved by binding of receptor-specific carriers to ligands. This concept leads towards a decrease in dose and thus in toxicity. Specific attachment to parenchymal cells improves tumor-organ contrast and therefore tumor detection. Specific uptake mechanisms also enable the assessment of organ function. Future design concepts of novel MR contrast agents may consider the desired uptake in specific cells or organs (ovaries, adrenal glands, lymph nodes etc.) with subsequent synthesis of appropriate carriers.
    Notes: Zusammenfassung In der vorliegenden Arbeit wird die Entwicklung und präklinische Erprobung rezeptorspezifischer MRT-Kontrastmittel zum verbesserten Nachweis pathologischer Prozesse und der Funktionsbeurteilung am Beispiel der Leber und des Pankreas beschrieben. Durch Kopplung geeigneter Carrier an die Liganden kann eine zellspezifische Aufnahme von MR-Kontrastmitteln erreicht werden. Im Vergleich zu unspezifischen Kontrastmitteln kann demnach die Dosis und die Toxizität reduziert werden. Durch die spezifische Aufnahme wird der Tumor-Organ-Kontrast und somit auch die Nachweisbarkeit von Tumoren verbessert. Über die verbesserte morphologische Beurteilung hinaus wird eine Funktionsbeurteilung von Organen oder Zellsystemen möglich. In Zukunft sollte es möglich sein, die Kontrastmittelsynthese nach der erwünschten Aufnahme in Zellsysteme (z. B. Ovarien, Nebennieren oder Lymphknoten etc.) zu planen, indem ein Carrier für das entsprechende Aufnahmesystem eingesetzt wird.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050053
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  • 10
    Electronic Resource
    Electronic Resource
    Primäres Non-Hodgkin-Lymphom der Schädelkalotte bei einem 11jährigen Mädchen Krankheitsverlauf und Literaturübersicht (1996)
    Springer
    Der Radiologe 36 (1996), S. 354-359 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Non-Hodgkin-Lymphom ; Schädel ; Kind ; Magnetresonanztomographie ; Key words Non-Hodgkin lymphoma ; Skull ; Child ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The authors present a rare case of solitary non-Hodgkin lymphoma (NHL) in the skull of an 11-year-old girl. The clinical, radiological and histological findings as well as a review of the literature are included in this report. The morphological features of intra- and extracerebral tumor masses and the change in tumor extension due to chemotherapy and radiation therapy were evaluated with magnetic resonance imaging. Although rare, NHL should be considered in the differential diagnosis of skull tumors in children.
    Notes: Zusammenfassung Es wird ein seltener Fall eines solitären, primär ossären Non-Hodgkin-Lymphoms (NHL) der Schädelkalotte im Kindesalter bei einem 11-jährigen Mädchen beschrieben. Klinische, radiologische und histologische Befunde werden analysiert. Anhand von Verlaufskontrollen mittels Magnetresonanztomographie (MRT) werden Änderungen der Tumormorphologie sowie die Reduktion der Tumorausbreitung infolge Chemo- und Radiotherapie evaluiert. Kriterien für die Diagnosesicherung und Differentialdiagnose werden anhand einer ausführlichen Literaturübersicht diskutiert. Bei der Beurteilung von Schädeltumoren im Kindesalter sollte das NHL differentialdiagnostisch berücksichtigt werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050082
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