Mapping of prostate cancer by ¹H MRSI

Abstract

In many studies, it has been demonstrated that (1)H MRSI of the human prostate has great potential to aid prostate cancer management, e.g. in the detection and localisation of cancer foci in the prostate or in the assessment of its aggressiveness. It is particularly powerful in combination with T2 -weighted MRI. Nevertheless, the technique is currently mainly used in a research setting. This review provides an overview of the state-of-the-art of three-dimensional MRSI, including the specific hardware required, dedicated data acquisition sequences and information on the spectral content with background on the MR-visible metabolites. In clinical practice, it is important that relevant MRSI results become available rapidly, reliably and in an easy digestible way. However, this functionality is currently not fully available for prostate MRSI, which is a major obstacle for routine use by inexperienced clinicians. Routine use requires more automation in the processing of raw data than is currently available. Therefore, we pay specific attention in this review on the status and prospects of the automated handling of prostate MRSI data, including quality control. The clinical potential of three-dimensional MRSI of the prostate is illustrated with literature examples on prostate cancer detection, its localisation in the prostate, its role in the assessment of cancer aggressiveness and in the selection and monitoring of therapy.

MR Spectroscopy in Prostate Cancer: New Algorithms to Optimize Metabolite Quantification

“…Conversely using AMARES in all the quantifications (except for phantom n°2), the null hypothesis can always be rejected. In scientific literature, LCMODEL is also used for quantitative MRS in the prostate [15, 21]. Unfortunately, the prostate basis set for LCMODEL is only available to the developer of this software and for an exclusive group of research centers.…”

“…It allows to obtain high resolution spectra, and for this reason many more metabolites are detectable with respect to in vivo 1 H-MRS [6,7], providing a survey about PCa metabolomics. Ex vivo (HR-MAS) and in vivo ( 1 H-MRS) studies show that metabolites, such as citrate (Cit), choline (Cho), creatine (Cr) and even polyamines are related with PCa [8–11], furthermore their concentrations have a good sensitivity and specificity for the diagnosis of PCa [12–15]. In particular the ratios between their concentrations, i.e.…”

1H MR spectroscopic imaging of the prostate at 7T using spectral‐spatial pulses

“…Although prostate 1 H‐MRSI at 1.5 and 3T is often performed with PRESS sequences equipped with slice‐selective pulses for localization and dual‐frequency pulses for selective water and lipid suppression , studies using SPSP‐MRSI type of sequences have also been presented . Contrary to the spectral selectivity of the SPSP pulse as the most challenging factor at 1.5 and 3T, requiring additional OVS pulses, the limiting factor at our 7T system is the available B 1 + transmit power with 8 × 1 kW amplifiers.…”

Practical aspects of prostate MRI: hardware and software considerations, protocols, and patient preparation

“…The 1H-MRSI acquisition has evolved from singlevoxel spectroscopy to 3D 1H-MRSI that is typically acquired using phase encoding in all three directions but is time consuming. Improvements in pulse sequence design have enabled the acquisition of metabolic information from the entire prostate at high resolution within less than 10 min with voxel sizes ranging from 0.2 to 0.5 cm 3 , making 1H-MRSI a clinically feasible technique [139,140]. These include using flyback echo-planar readout gradients to improve efficiency and robustness to errors and non-uniform undersampling, and compressed sensing to accelerate the acquisition [141,142].…”