Proton magnetic resonance spectroscopic imaging (H MRSI) enables non-invasive assessment of certain metabolites in the prostate gland. Several studies have demonstrated that this metabolic information, in combination with anatomical information from T2-weighted MR imaging significantly improves prostate cancer detection, localization and disease characterization. The technology of H MRSI is continuously evolving with improvements of hardware and acquisition methods. Recently,P and C MRSI of the prostate have regained new interest after a dormant period of decades. This review focuses on recent technical progress of in vivoH MRSI of the prostate, in particular those that enhance clinical applicability at 3T with respect to commonly used techniques to examine the prostate. These developments consist of higher magnetic field strengths, and better MR coils and acquisition techniques. Besides the improvements for H MRSI, the developments and opportunities forP and C MRSI for the prostate are reviewed. Finally, we briefly reviewC MRS of the prostate, in particular the new possibilities with hyperpolarized substrates.

This is an open access article under the terms of the Creat ive Commo ns Attri butio n-NonCo mmerc ial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

The good signal-to-noise ratio and low chemical shift artifacts of GOIA-sLASER at an echo time of 88 milliseconds enable acquisition of high-quality 3D-H-MRSI of the prostate without endorectal coil in less than 10 minutes. This facilitates reconstruction of easy interpretable, quantitative metabolite maps for routine clinical applications of prostate MRSI.

Purpose Quality control (QC) is a prerequisite for clinical MR spectroscopic imaging (MRSI) to avoid that bad spectra hamper data interpretation. The aim of this work was to present a simple automatic QC for prostate 1H MRSI that can handle data obtained with different commonly used pulse sequences, echo times, field strengths, and MR platforms. Methods A QC method was developed with a ratio (Qratio) where the numerator and the denominator are functions of several signal heights, logically combined for their positive or negative contribution to spectral quality. This Qratio was tested on 4 data sets obtained at 1.5, 3, and 7T, with and without endorectal coil and different localization sequences and echo times. Spectra of 25,248 voxels in 26 prostates were labeled as acceptable or unacceptable by MRS experts as gold standard. A threshold value was determined for Qratio from a subset of voxels, labeled in consensus by 4 experts, for an optimal accuracy to separate spectra. Results Applying this Qratio threshold to the remaining test voxels, an automatic separation of good and bad spectra was possible with an accuracy of 0.88, similar to manual separation between the 2 classes. Qratio values were used to generate maps representing spectral quality on a binary or continuous scale. Conclusion Automated QC of prostate 1H MRSI by Qratio is fast, simple, easily transferable and more practical than supervised feature extraction methods and therefore easy to integrate into different clinical MR systems. Moreover, quality maps can be generated to read the reliability of spectra in each voxel.

Purpose: To investigate the associations of metabolite levels derived from magnetic resonance spectroscopic imaging (MRSI) and 18F-fluciclovine positron emission tomography (PET) with prostate tissue characteristics.Methods: In a cohort of 19 high-risk prostate cancer patients that underwent simultaneous PET/MRI, we evaluated the diagnostic performance of MRSI and PET for discrimination of aggressive cancer lesions from healthy tissue and benign lesions. Data analysis comprised calculations of correlations of mean standardized uptake values (SUVmean), maximum SUV (SUVmax), and the MRSI-derived ratio of (total choline + spermine + creatine) to citrate (CSC/C). Whole-mount histopathology was used as gold standard.Results: The results showed a moderate significant correlation between both SUVmean and SUVmax with CSC/C ratio.Conclusions: We demonstrated that the simultaneous acquisition of 18F-fluciclovine PET and MRSI with an integrated PET/MRI system is feasible and a combination of these imaging modalities has potential to improve the diagnostic sensitivity and specificity of prostate cancer lesions.