TY  - CHAP
A1  - Bitz, Andreas
A1  - Kraff, O.
A1  - Orzada, S.
A1  - Maderwald, S.
A1  - Brote, I.
A1  - Ladd, M.
T1  - Experimental and Numerical Assessment of RF Safety of Transmit Coils at 7 Tesla
T2  - ISMRM workshop on MR safety 2010 : RF heating of the human in MRI : workshop series. The Washington County Historic Courthouse, Stillwater, Minnesota, USA, 15 - 17 October 2010
Y1  - 2010
SN  - 978-1-62276-088-6
SP  - 195
ER  - 
TY  - CHAP
A1  - Bitz, Andreas
A1  - Kraff, O.
A1  - Orzada, S.
A1  - Maderwald, S.
A1  - Brote, I.
A1  - Johst, S.
A1  - Ladd, E.
T1  - Assessment of RF Safety of Transmit Coils at 7 Tesla by Experimental and Numerical Procedures (490.)
T2  - 19th annual ISMRM scientific meeting and exhibition 2011 : Montreal, Quebec, Canada, 7 - 13 May 2011
Y1  - 2012
SN  - 978-1-61839-284-8
IS  - Volume 1
SP  - 475
PB  - Curran
CY  - Red Hook, NY
ER  - 
TY  - JOUR
A1  - Orzada, S.
A1  - Maderwald, S.
A1  - Poser, B. A.
A1  - Johst, S.
A1  - Kannengiesser, S.
A1  - Ladd, M. E.
A1  - Bitz, Andreas
T1  - Time-interleaved acquisition of modes: an analysis of SAR and image contrast implications
JF  - Magnetic Resonance in Medicine
N2  - s the magnetic field strength and therefore the operational frequency in MRI are increased, the radiofrequency wavelength approaches the size of the human head/body, resulting in wave effects which cause signal decreases and dropouts. Especially, whole-body imaging at 7 T and higher is therefore challenging. Recently, an acquisition scheme called time-interleaved acquisition of modes has been proposed to tackle the inhomogeneity problems in high-field MRI. The basic premise is to excite two (or more) different Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-1 modes using static radiofrequency shimming in an interleaved acquisition, where the complementary radiofrequency patterns of the two modes can be exploited to improve overall signal homogeneity. In this work, the impact of time-interleaved acquisition of mode on image contrast as well as on time-averaged specific absorption rate is addressed in detail. Time-interleaved acquisition of mode is superior in Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-2 homogeneity compared with conventional radiofrequency shimming while being highly specific absorption rate efficient. Time-interleaved acquisition of modes can enable almost homogeneous high-field imaging throughout the entire field of view in PD, T2, and T2*-weighted imaging and, if a specified homogeneity criterion is met, in T1-weighted imaging as well.
Y1  - 2012
U6  - http://dx.doi.org/10.1002/mrm.23081
SN  - 1522-2594
VL  - 67
IS  - 4
SP  - 1033
EP  - 1041
PB  - Wiley-Liss
CY  - New York
ER  - 
TY  - JOUR
A1  - Umutlu, L.
A1  - Maderwald, S.
A1  - Kinner, S.
A1  - Kraff, O.
A1  - Bitz, Andreas
A1  - Orzada, S.
A1  - Johst, S.
A1  - Wrede, K.
A1  - Forsting, M.
A1  - Ladd, M. E.
A1  - Lauenstein, T. C.
A1  - Quick, H. H.
T1  - First-pass contrast-enhanced renal MRA at 7 Tesla: initial results
JF  - European Radiology
Y1  - 2013
U6  - http://dx.doi.org/10.1007/s00330-012-2666-0
SN  - 1432-1084
VL  - 23
IS  - 4
SP  - 1059
EP  - 1066
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Vos, E. K.
A1  - Lagemaat, M. W.
A1  - Barentsz, J. O.
A1  - Fütterer, J. J.
A1  - Zamecnik, P.
A1  - Roozen, H.
A1  - Orzada, S.
A1  - Bitz, Andreas
A1  - Maas, M. C.
A1  - Scheenen, T. W. J.
T1  - Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla
JF  - European Radiology
N2  - Objectives
To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T).

Materials & methods
Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored images for image quality, visibility of anatomical structures, and presence of artefacts. Krippendorff’s alpha and weighted kappa statistics were used to assess inter-observer agreement. Visibility of prostate cancer lesions was assessed by directly linking the T2w images to the confirmed location of prostate cancer on histopathology.

Results
T2w imaging at 7T was achievable with ‘satisfactory’ (3/5) to ‘good’ (4/5) quality. Visibility of anatomical structures was predominantly scored as ‘satisfactory’ (3/5) and ‘good’ (4/5). If artefacts were present, they were mostly motion artefacts and, to a lesser extent, aliasing artefacts and noise. Krippendorff’s analysis revealed an α = 0.44 between three readers for the overall image quality scores. Clinically significant cancer lesions in both peripheral zone and transition zone were visible at 7T.

Conclusion
T2w imaging with satisfactory to good quality can be routinely acquired, and cancer lesions were visible in patients with prostate cancer at 7T using only an external transmit/receive body array coil.
Y1  - 2014
U6  - http://dx.doi.org/10.1007/s00330-014-3234-6
SN  - 1432-1084
VL  - 24
IS  - 8
SP  - 1950
EP  - 1958
PB  - Springer
CY  - Cham
ER  -