Imaging Hyperpolarized Pyruvate and Lactate after Blood-Brain Barrier Disruption with Focused Ultrasound.

Imaging of hyperpolarized C-labeled substrates has emerged as an important magnetic resonance (MR) technique to study metabolic pathways in real time in vivo. Even though this technique has found its way to clinical trials, in vivo dynamic nuclear polarization is still mostly applied in preclinical models. Its tremendous increase in signal-to-noise ratio (SNR) overcomes the intrinsically low MR sensitivity of the C nucleus and allows real-time metabolic imaging in small structures like the mouse brain.

Simple and broadly applicable automatic quality control for 3D H MR spectroscopic imaging data of the prostate.

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 H 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.

Evaluation of fitting models for prostate tissue characterization using extended-range b-factor diffusion-weighted imaging.

Purpose: To compare the fitting and tissue discrimination performance of biexponential, kurtosis, stretched exponential, and gamma distribution models for high b-factor diffusion-weighted images in prostate cancer.

Methods: Diffusion-weighted images with 15 b-factors ranging from b = 0 to 3500 s/mm were obtained in 62 prostate cancer patients. Pixel-wise signal decay fits for each model were evaluated with the Akaike Information Criterion (AIC).

In vivo MR spectroscopic imaging of the prostate, from application to interpretation.

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.

Growth inhibition in a brain metastasis model by antibody delivery using focused ultrasound-mediated blood-brain barrier disruption.

HER2-targeting antibodies (i.e. trastuzumab and pertuzumab) prolong survival in HER2-positive breast cancer patients with extracranial metastases.

Safety Validation of Repeated Blood-Brain Barrier Disruption Using Focused Ultrasound.

The purpose of this study was to investigate the effects on the brain of multiple sessions of blood-brain barrier (BBB) disruption using focused ultrasound (FUS) in combination with micro-bubbles over a range of acoustic exposure levels. Six weekly sessions of FUS, using acoustical pressures between 0.66 and 0.

Update on Clinical Magnetic Resonance-Guided Focused Ultrasound Applications.

In this review, several clinical applications of magnetic resonance (MR)-guided focused ultrasound (FUS) are updated. MR-guided FUS is used clinically for thermal ablation of uterine fibroids and bone metastases. Thousands of patients have successfully been treated.

Computer-extracted Features Can Distinguish Noncancerous Confounding Disease from Prostatic Adenocarcinoma at Multiparametric MR Imaging.

Purpose: To determine the best features to discriminate prostate cancer from benign disease and its relationship to benign disease class and cancer grade.

Materials And Methods: The institutional review board approved this study and waived the need for informed consent. A retrospective cohort of 70 patients (age range, 48-70 years; median, 62 years), all of whom were scheduled to undergo radical prostatectomy and underwent preoperative 3-T multiparametric magnetic resonance (MR) imaging, including T2-weighted, diffusion-weighted, and dynamic contrast material-enhanced imaging, were included.

Multiparametric Magnetic Resonance Imaging for Discriminating Low-Grade From High-Grade Prostate Cancer.

Objective: The aim of this study was to determine and validate the optimal combination of parameters derived from 3-T diffusion-weighted imaging, dynamic contrast-enhanced imaging, and magnetic resonance (MR) spectroscopic imaging for discriminating low-grade from high-grade prostate cancer (PCa).

Materials And Methods: The study was approved by the institutional review board, and the need for informed consent was waived. Ninety-four patients with PCa who had undergone multiparametric MR imaging (MRI) before prostatectomy were included.

(31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization.

Purpose: Optimization of phosphorus ((31) P) MR spectroscopic imaging (MRSI) of the human prostate at 7 T by the evaluation of T1 relaxation times and the Nuclear Overhauser Effect (NOE) of phosphorus-containing metabolites.

Methods: Twelve patients with prostate cancer and one healthy volunteer were scanned on a 7 T whole-body system using a (31) P endorectal coil combined with an eight-channel (1) H body array coil. T1 relaxation times were measured using progressive saturation in a two-dimensional localization sequence.

Metabolite ratios in 1H MR spectroscopic imaging of the prostate.

In (1)H MR spectroscopic imaging ((1)H-MRSI) of the prostate the spatial distribution of the signal levels of the metabolites choline, creatine, polyamines, and citrate are assessed. The ratio of choline (plus spermine as the main polyamine) plus creatine over citrate [(Cho+(Spm+)Cr)/Cit] is derived from these metabolites and is used as a marker for the presence of prostate cancer. In this review, the factors that are of importance for the metabolite ratio are discussed.

Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer.

Objectives: The aim of this study was to identify characteristics of phosphorus (P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo P 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 P 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.

Feasibility of T2 -weighted turbo spin echo imaging of the human prostate at 7 tesla.

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.

Mapping of prostate cancer by 1H MRSI.

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.

Assessment of prostate cancer aggressiveness using dynamic contrast-enhanced magnetic resonance imaging at 3 T.

Background: A challenge in the diagnosis of prostate cancer (PCa) is the accurate assessment of aggressiveness.

Objective: To validate the performance of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of the prostate at 3 tesla (T) for the assessment of PCa aggressiveness, with prostatectomy specimens as the reference standard.

Design, Settings, And Participants: A total of 45 patients with PCa scheduled for prostatectomy were included.

In vivo (1) H MR spectroscopic imaging of aggressive prostate cancer: can we detect lactate?

Purpose: A semi-LASER sequence was optimized for in vivo lactate detection in the prostate.

Methods: The ethical committee waived the need for informed consent to measure 17 patients with high grade prostate cancer on a 3T system. A semi-LASER sequence was used with an echo time of 144 ms and optimized interpulse timing for a spectral citrate shape with high signal intensity.

Prostate cancer aggressiveness: in vivo assessment of MR spectroscopy and diffusion-weighted imaging at 3 T.

Purpose: To determine the individual and combined performance of magnetic resonance (MR) spectroscopic imaging and diffusion-weighted (DW) imaging at 3 T in the in vivo assessment of prostate cancer aggressiveness by using histopathologically defined regions of interest on radical prostatectomy specimens to define the prostate cancer regions to be investigated.

Materials And Methods: The local institutional ethics review board approved this retrospective study and waived the informed consent requirement. Fifty-four patients with biopsy-proved prostate cancer underwent clinical MR spectroscopic imaging followed by prostatectomy.

In vivo 31P MR spectroscopic imaging of the human prostate at 7 T: safety and feasibility.

(31)P MR spectroscopic imaging of the human prostate provides information about phosphorylated metabolites that could be used for prostate cancer characterization. The sensitivity of a magnetic field strength of 7 T might enable 3D (31)P MR spectroscopic imaging with relevant spatial resolution in a clinically acceptable measurement time. To this end, a (31)P endorectal coil was developed and combined with an eight-channel (1)H body-array coil to relate metabolic information to anatomical location.

In vivo assessment of prostate cancer aggressiveness using magnetic resonance spectroscopic imaging at 3 T with an endorectal coil.

Background: One of the most important clinical challenges in prostate cancer (PCa) management is an in vivo assessment of cancer aggressiveness.

Objective: To validate the performance of magnetic resonance (MR) spectroscopic imaging (MRSI) of the prostate at 3 T for the purpose of assessing tumour aggressiveness based on the ratio of choline plus creatine to citrate (Cho+Cr/Cit) and of choline to creatine (Cho/Cr), using the Gleason score of the radical prostatectomy (RP) specimen as the gold standard.

Design, Setting, And Participants: A total of 43 biopsy-proven PCa patients with 53 clinically relevant tumour foci were retrospectively included in this study.