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  • 1
    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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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Clinical utility of contrast-enhanced MR angiography (1997)
    Springer
    European radiology 7 (1997), S. S178 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Magnetic resonance angiography ; Contrast media ; Pulmonary arteries ; Carotid arteries ; Renal arteries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. MR angiography (MRA) is a technique under ongoing discussion. Its non-invasiveness and sensitivity to flow irregularities make it an investigational technique which is easy to apply but which does not always lead to comprehensive results. It requires special skill to perform and also experience for correct interpretation of the results. The lengthiness of the procedure combined with certain physical properties tends to limit its use to mostly neurovascular applications. With the introduction of ultrafast MRA in conjunction with peripheral bolus-injection of extracellular contrast media, a new approach to the imaging of such regions as the thoracic and abdominal vasculature not to mention other vascular territories has become possible. In this paper, considerations of bolus and measurement optimization and timing protocols for dedicated indications are presented together with an overview on the experience acquired to date for CE-MRA of the carotid artery, mediastinal and pulmonary vessels, abdominal vasculature, and peripheral vessels. The main advantage of ultrafast CE-MRA is that patients are subjected to much more tolerable breath-hold investigations with the result that physiological motion such as peristalsis or major pulsation is minimised.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00006890
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of slice orientation in 3D magnetic resonance angiography (MRA) of the supra-aortic arteries (1991)
    Springer
    European radiology 1 (1991), S. 158-164 
    Details
    ISSN: 1432-1084
    Keywords: Magnetic resonance ; Magnetic resonance-pulse sequences ; Magnetic resonance angiography ; Carotid arteries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Three-dimensional (3D) time-of-flight methods are used to study anatomy and pathology of the supra-aortic arteries because they are quick and optimal for fast-flow conditions. Although highest signal intensities can be obtained by orientating the sections perpendicular to the long axis of the artery (axial), sagittal and/or coronal slice orientations cover the regions of interest with smaller volumes and therefore give adequate information in less time. Sagittal and coronal time-of-flight magnetic resonance angiography (MRA) gave excellent results (sensitivity 92.3%, specificity 85.7%, accuracy 90.9%) compared with intra-arterial digital subtraction angiography (DSA) in 30 patients, when coronal and sagittal acquisition were combined for final diagnosis. These values decreased to 69.6%/57.1%/66.7% for coronal and 83.6%/78.6%/81.7% for sagittal sections. Reasons for the variable extent of signal dropout at the site of a stenosis and for the different appearances of post-stenotic slow flow in the various planes are explained by T1 phenomena and intravoxel phase dispersion due to variable parameter settings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00451301
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  • 4
    Electronic Resource
    Electronic Resource
    Einsatz von Gadoteridol in der MR-Diagnostik rheumatoider Gelenkveränderungen (1996)
    Springer
    Der Radiologe 36 (1996), S. 141-147 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Magnetresonanztomographie ; MR-Kontrastmittel ; paramagnetische ; Arthritiden ; Frühdiagnostik ; Chronische Polyarthritis ; Key words Magnetic resonance imaging ; MR contrast media ; paramagnetic ; Inflammatory joint disease ; diagnosis ; Rheumatoid arthritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: To investigate the diagnostic and clinical usefulness of a new non-ionic, hydrophilic gadolinium (III) chelate [Gd(HP-DO3A), gadoteridol, ProHance] and to compare it with Gd-DTPA (gadopentetate dimeglumine, Magnevist). Methods: In a Phase III clinical trial, 20 patients with rheumatic joint disease were examined before and after intravenous administration of gadoteridol in two different doses (0.1 and 0.3 mmol/kg bodyweight). Magnetic resonance imaging (MRI) was performed at 1.5 T with T1-weighted FLASH and T2-weighted spin echo sequences. Fourteen patients were examined with gadopentetate dimeglumine for comparison. Dynamic changes of signal intensity in the joints and muscle tissue were determined quantitatively. Results: No significant changes in cardiovascular data and no adverse effects occurred after injection of gadoteridol. The 0.3 mmol/kg dose showed no advantage in diagnostic contrast over the 0.1 mmol/kg dose. No significant differences (p 〉 0.01) were noted between gadoteridol and gadopentetate dimeglumine in patients with early rheumatoid arthritis. Conclusion: Gadoteridol proved useful in the detection of early rheumatoid arthritis. No significant differences were observed between the two gadoteridol doses. There were no diagnostically relevant differences between gadoteridol and gadopentetate dimeglumine.
    Notes: Zusammenfassung Ziel der Studie war es, die klinische Verträglichkeit und die diagnostische Wertigkeit von Gadoteridol für die Beurteilung entzündlicher Gelenkveränderungen zu untersuchen. Im Rahmen einer Phase-III-Studie wurden 20 Patienten mit rheumatischen Gelenkerkrankungen vor und nach intravenöser Injektion des gadoliniumhaltigen, paramagnetischen Kontrastmittels Gadoteridol (Gd(HP-DO3A), ProHance®) MR-tomographisch untersucht. Zwei Kontrastmitteldosen (0,1 und 0,3 mmol/kg Körpergewicht) wurden evaluiert und ein Vergleichskollektiv von 14 Patienten mit Gadopentetat Dimeglumin (Gd-DTPA, Magnevist®) untersucht. Dynamische Signalintensitätsveränderungen der Gelenkstrukturen nach Kontrastmittelinjektion wurden quantitativ bestimmt. Bei guter Verträglichkeit der Kontrastmittelverabreichung ergaben sich bis 2 h nach Injektion von Gadoteridol keine signifikanten Änderungen der Kreislaufparameter. Die Dosis von 0,1 mmol/kg Körpergewicht erwies sich bei 1,5 Tesla als diagnostisch ausreichend. Gadoteridol zeigte im Vergleich zu Gadopentetat Dimeglumin bei frühen rheumatischen Gelenkveränderungen keine signifikanten Unterschiede bezogen auf qualitative Parameter und quantitativ bestimmte dynamische Signalintensitätsveränderungen (p 〉 0,01).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050051
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    Paper (German National Licenses)
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