TY  - JOUR
A1  - Lagemaat, Miriam W.
A1  - Breukels, Vincent
A1  - Vos, Eline K.
A1  - B., Adam
A1  - Uden, Mark J. van
A1  - Orzada, Stephan
A1  - Bitz, Andreas
A1  - Maas, Marnix C.
A1  - Scheenen, Tom W. J.
T1  - ¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses
JF  - Magnetic Resonance in Medicine
N2  - Purpose
To assess the feasibility of prostate ¹H MR spectroscopic imaging (MRSI) using low-power spectral-spatial (SPSP) pulses at 7T, exploiting accurate spectral selection and spatial selectivity simultaneously.

Methods
A double spin-echo sequence was equipped with SPSP refocusing pulses with a spectral selectivity of 1 ppm. Three-dimensional prostate ¹H-MRSI at 7T was performed with the SPSP-MRSI sequence using an 8-channel transmit array coil and an endorectal receive coil in three patients with prostate cancer and in one healthy subject. No additional water or lipid suppression pulses were used.

Results
Prostate ¹H-MRSI could be obtained well within specific absorption rate (SAR) limits in a clinically feasible time (10 min). Next to the common citrate signals, the prostate spectra exhibited high spermine signals concealing creatine and sometimes also choline. Residual lipid signals were observed at the edges of the prostate because of limitations in spectral and spatial selectivity.

Conclusion
It is possible to perform prostate ¹H-MRSI at 7T with a SPSP-MRSI sequence while using separate transmit and receive coils. This low-SAR MRSI concept provides the opportunity to increase spatial resolution of MRSI within reasonable scan times.
Y1  - 2016
U6  - http://dx.doi.org/10.1002/mrm.25569
SN  - 1522-2594
VL  - 75
IS  - 3
SP  - 933
EP  - 945
PB  - International Society for Magnetic Resonance in Medicine
ER  - 
TY  - JOUR
A1  - Lagemaat, Miriam W.
A1  - Maas, Marnix C.
A1  - Vos, Eline K.
A1  - Bitz, Andreas
A1  - Orzada, Stephan
A1  - Weiland, Elisabeth
A1  - Uden, Mark J. van
A1  - Kobus, Thiele
A1  - Heerschap, Arend
A1  - Scheenen, Tom W. J.
T1  - (31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization
JF  - Magnetic Resonance in Medicine
Y1  - 2015
U6  - http://dx.doi.org/10.1002/mrm.25209
SN  - 1522-2594
VL  - 73
IS  - 3
SP  - 909
EP  - 920
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Lagemaat, Miriam W.
A1  - Vos, Eline K.
A1  - Maas, Marnix C.
A1  - Bitz, Andreas
A1  - Orzada, Stephan
A1  - Uden, Mark J. van
A1  - Kobus, Thiele
A1  - Heerschap, Arend
A1  - Scheenen, Tom W. J.
T1  - Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer
JF  - Investigative Radiology
N2  - Objectives 
The aim of this study was to identify characteristics of phosphorus (³¹P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo ³¹P magnetic resonance spectroscopic imaging (MRSI) at 7 T.

Materials and Methods 
In this institutional review board–approved study, 15 patients with biopsy-proven prostate cancer underwent T₂-weighted magnetic resonance imaging and 3-dimensional ³¹P MRSI at 7 T. Voxels were selected at the tumor location, in normal-appearing peripheral zone tissue, normal-appearing transition zone tissue, and in the base of the prostate close to the seminal vesicles. Phosphorus metabolite ratios were determined and compared between tissue types.

Results 
Signals of phosphoethanolamine (PE) and phosphocholine (PC) were present and well resolved in most ³¹P spectra in the prostate. Glycerophosphocholine signals were observable in 43% of the voxels in malignant tissue, but in only 10% of the voxels in normal-appearing tissue away from the seminal vesicles. In many spectra, independent of tissue type, 2 peaks resonated in the chemical shift range of inorganic phosphate, possibly representing 2 separate pH compartments. The PC/PE ratio in the seminal vesicles was highly elevated compared with the prostate in 5 patients. A considerable overlap of ³¹P metabolite ratios was found between prostate cancer and normal-appearing prostate tissue, preventing direct discrimination of these tissues. The only 2 patients with high Gleason scores tumors (≥4+5) presented with high PC and glycerophosphocholine levels in their cancer lesions.

Conclusions 
Phosphorus MRSI at 7 T shows distinct features of phospholipid metabolites in the prostate gland and its surrounding structures. In this exploratory study, no differences in ³¹P metabolite ratios were observed between prostate cancer and normal-appearing prostate tissue possibly because of the partial volume effects of small tumor foci in large MRSI voxels.
Y1  - 2014
U6  - http://dx.doi.org/10.1097/RLI.0000000000000012
SN  - 1536-0210
VL  - 49
IS  - 5
SP  - 363
EP  - 372
PB  - Lippincott Williams & Wilkins
CY  - Philadelphia, Pa.
ER  -