Contrast-enhanced, high-resolution, susceptibility-weighted magnetic resonance imaging of the brain: dose-dependent optimization at 3 tesla and 1.5 tesla in healthy volunteers.
ABSTRACT We sought to determine the optimal dose of a contrast agent with known high relaxivity on 1.5 and 3 Tesla scanners that would achieve the best compromise between image quality and scan time for the clinical application of contrast-enhanced susceptibility-weighted imaging (CE-SWI).
Pre- and postcontrast SWI was performed with different contrast agent doses (0.05, 0.1, and 0.2 mmol/kg gadobenate dimeglumine) at both 1.5 and 3 T in 6 healthy volunteers, resulting in 72 examinations. Venograms were created from minimum intensity projection reconstructions over specified deep white matter volumes to enhance the visual appearance of connected venous structures. Three independent radiologists blindly rated the visibility of the veins on a continuous scale of 1 to 10. A general linear model was used for statistical evaluation, with fixed effects of the contrast agent dose, the field strength, the rater and the patients as a random effect.
With CE-SWI, we found significant differences in the visibility of the deep veins dependent on the contrast media dose (P=0.02). At 3 T, the visibility of deep venous vessels, with regard to susceptibility effect, image quality, and scan time reduction after a standard contrast agent dose 0.1 mmol/kg was significantly better than that achieved with 0.05 mmol/kg. The visibility was considered equal with 0.1 mmol/kg of the contrast agent to the precontrast images and a dose of 0.2 mmol/kg. At 1.5 T, no significant difference was found between the 4 contrast agent doses. We found no difference in the visibility of the veins with the shorter sequences at 3 T compared with the sequences at 1.5 T.
Only a standard dose (0.1 mmol/kg) of gadobenate dimeglumine is required to achieve the optimum susceptibility effect and image quality at 3 T, together with a reduced scan time. This result can be attributed to the higher relaxivity of gadobenate dimeglumine, compared with conventional gadolinium chelates.
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ABSTRACT: Die molekulare Bildgebung beschäftigt sich mit der Darstellung, Beschreibung und Quantifizierung biologischer und physiologischer Prozesse auf zellulärer und molekularer Ebene. In der letzten Zeit beginnt sich die molekulare Bildgebung auch in der Mammadiagnostik zu etablieren. Im Rahmen dieses Übersichtsartikels soll ein Überblick über die sich noch in der Entwicklung befindlichen präklinischen sowie die bereits etablierten klinischen Verfahren gegeben werden. Die molekulare nuklearmedizinische Brustbildgebung (brustspezifische Gammakamerabildgebung [BSGI] und Positronenemissionsmammographie [PEM]) und die dabei zur Anwendung kommenden spezifischen Radiotracer und Kontrastmittel werden besprochen und die Möglichkeiten der MRT in der funktionellen (DWI) und metabolischen (MRSI) Bildgebung von Brustläsionen und die kombinierte Anwendung der nuklearmedizinischen MR-tomographischen Bildgebung (PET/MRT) erläutert. Weiter soll ein Überblick über die präklinische Verfahren, die optische und photoakustische Bildgebung und ihre möglichen klinischen Anwendungen gegeben werden. Molecular imaging is concerned with the presentation, description and quantification of biological and physiological processes at the cellular and molecular level. Most recently molecular imaging has started to become established in breast diagnostics. This review article will give an overview of procedures which are either in the preclinical development stage or which have already become clinically established. Molecular nuclear medicine breast imaging (breast-specific gamma imaging [BSGI] and positron emission mammography [PEM]) together with specific radiotracers and contrast media will be discussed. The possibilities for magnetic resonance imaging in functional (DWI) and metabolic (MRSI) imaging of breast lesions and the combined application of nuclear medicine and magnetic resonance imaging (PET/MRI) will be explained. Furthermore, an overview on the preclinical procedure and the possible clinical applications of optical and photoacoustic imaging will be given. SchlüsselwörterMolekulare Bildgebung-Optische Bildgebung-Positronenemissionstomographie/Magnetresonanztomographie (PET/MRT)-„Diffusion-weighted imaging“ (DWI)-„Magnetic resonance spectroscopic imaging“ (MRSI) KeywordsMolecular imaging-Optical imaging-Positron emission tomography/magnetic resonance imaging (PET/MRI)-Diffusion-weighted imaging (DWI)-Magnetic resonance spectroscopic imaging (MRSI)Der Radiologe 50(11):1030-1038. · 0.47 Impact Factor
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ABSTRACT: MR imaging without and with gadolinium-based contrast agents (GBCAs) is an important imaging tool for defining normal anatomy and characteristics of lesions. GBCAs have been used in contrast-enhanced MR imaging in defining and characterizing lesions of the central nervous system for more than 20 years. The combination of unenhanced and GBCA-enhanced MR imaging is the clinical gold standard for the noninvasive detection and delineation of most intracranial and spinal lesions. MR imaging has a high predictive value that rules out neoplasm and most inflammatory and demyelinating processes of the central nervous system.Magnetic resonance imaging clinics of North America 11/2012; 20(4):649-85.
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ABSTRACT: Conventional magnetic resonance imaging (MRI) assesses neurodegenerative structural changes in the cerebral anatomy of Parkinson's disease (PD) patients but cannot detect non-structural abnormalities; however, enhanced T2 star weighted angiography (ESWAN) can precisely indicate PD-related substantia nigra (SN) iron deposition. The differences in ESWAN-based parameters between different PD stages were assessed using midbrain iron deposits of 20 PD patients aged 64.3±12.7 (41-85) years grouped by Hoehn and Yahr staging into minimal (stages ≤2.5) or moderate to severe (stages ≥3.0) motor impairment groups and 14 healthy control subjects. Conventional MRI and ESWAN measurements of mean phase value (MPV) and midbrain dimensions (width and diameter) revealed similar anatomical characteristics; however, ESWAN revealed the presence of smaller MPVs and SN pars compacta (SNc) (P<0.01) and a negative correlation between reduction extent and motor impairment (P<0.01). SNc width to midbrain diameter was reduced in moderate to severe impairment patients versus control and minimal impairment patients (both P<0.01). A positive correlation was found between MPV and width or SNc width to midbrain diameter ratio (P<0.01 and P<0.05, respectively). Minimal impairment group mean MPV and substantia nigra pars reticulata (SNr) width evidenced no significant reduction, unlike significant reductions in the moderate to severe impairment group (P<0.01). No significant changes were observed in MPV or width in the RN region (P>0.05). ESWAN allows for early and accurate iron deposition determination in PD patients, particularly useful as a supplement to conventional MRI in early-stage PD patients.Magnetic Resonance Imaging 06/2013; · 2.06 Impact Factor