TY  - JOUR
A1  - Maas, Marnix C.
A1  - Vos, Eline K.
A1  - Lagemaat, Miriam W.
A1  - Bitz, Andreas
A1  - Orzada, Stephan
A1  - Kobus, Thiele
A1  - Kraff, Oliver
A1  - Maderwald, Stefan
A1  - Ladd, Mark E.
A1  - Scheenen, Tom W. J.
T1  - Feasibility of T₂-weighted turbo spin echo imaging of the human prostate at 7 tesla
JF  - Magnetic Resonance in Medicine
N2  - Purpose
To demonstrate that high quality T₂-weighted (T2w) turbo spin-echo (TSE) imaging of the complete prostate can be achieved routinely and within safety limits at 7 T, using an external transceive body array coil only.

Methods
Nine healthy volunteers and 12 prostate cancer patients were scanned on a 7 T whole-body system. Preparation consisted of B₀ and radiofrequency shimming and localized flip angle calibration. T₁ and T₂ relaxation times were measured and used to define the T2w-TSE protocol. T2w imaging was performed using a TSE sequence (pulse repetition time/echo time 3000–3640/71 ms) with prolonged excitation and refocusing pulses to reduce specific absorption rate.

Results
High quality T2w TSE imaging was performed in less than 2 min in all subjects. Tumors of patients with gold-standard tumor localization (MR-guided biopsy or prostatectomy) were well visualized on 7 T imaging (n = 3). The number of consecutive slices achievable within a 10-g averaged specific absorption rate limit of 10 W/kg was ≥28 in all subjects, sufficient for full prostate coverage with 3-mm slices in at least one direction.

Conclusion
High quality T2w TSE prostate imaging can be performed routinely and within specific absorption rate limits at 7 T with an external transceive body array.
Y1  - 2014
U6  - http://dx.doi.org/10.1002/mrm.24818
SN  - 1522-2594
VL  - 71
IS  - 5
SP  - 1711
EP  - 1719
PB  - Wiley-VCH
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  -