Keywords: Prostate, Prostate

Motivation: Pathogenic DDR gene alterations are associated with aggressive disease and poor outcomes among prostate cancer (PCa) patients.

Goal(s): To develop a radiomics-based pre-testing model for identifying DDR mutation carriers among PCa patients.

Approach: A total of 225 patients from three centers with both multiparameter MRI and genetic DDR mutations testing were included. Radiomic models were established based on T2WI and ADC sequences of MRI images. The predictive values were validated in both internal and external validation cohorts.

Results: The radiomics-based model exhibited an AUC of 0.835 in the training dataset, 0.824 in the internal validation dataset, and 0.836 in the external validation dataset.

Impact: In the current study, we introduced a noninvasive radiomics feature-based tool designed to predict pDDRg mutations in prostate cancer patients. External validation of the novel tool by datasets from other medical centers revealed a high predictive accuracy for pDDRg mutations.

Keywords: Prostate, Prostate, Hyperpolarized 13C MRI

Motivation: Hyperpolarized (HP) ¹³C-pyruvate MRI can address limitations of PSMA-PET for monitoring therapy and evaluating treatment-emergent, lethal subtypes of prostate cancer.

Goal(s): To establish and characterize a novel radiomics framework of tumor metabolism in advanced prostate cancer based on whole abdominopelvic HP MRI.

Approach: We extracted 316 metabolic features from 16 patients. Following feature selection and classification, their prognostic values were evaluated using uni- and multivariate survival analyses.

Results: Metabolic feature k_PL,median (pyruvate-to-lactate conversion rate) significantly predicted both progression-free (p<0.01) and overall (p<0.05) survivals with longer median PFS (11.2 vs 0.5 months) and OS (NR vs 18.4 months) in the lower- vs higher-k_PL subgroups.

Impact: A novel radiomics framework based on whole abdominopelvic hyperpolarized ¹³C-pyruvate MRI extracted and evaluated 316 metabolic features of advanced prostate cancer. Selected features significantly predicted clinical outcome measures (PFS and OS), strongly supporting further investigation of their prognostic values.

Keywords: Prostate, Diffusion/other diffusion imaging techniques, Prostate, Diffusion Denoising

Motivation: High-resolution (HR) DWI, although beneficial for prostate tissue characterization and cancer diagnosis, suffers from low signal-to-noise ratio (SNR). The common strategy of averaging to increase SNR prolongs the acquisition time (TA). 

Goal(s): Decreasing the number of repetitions for averaging while maintaining the SNR for HR prostate DWI.

Approach: Eddy Current-Nulled Convex Optimized Diffusion Encoding (ENCODE) combined with random matrix theory (RMT)-based denoising to reduce the repetitions while maintaining SNR.

Results: HR-ENCODE-RMT (TA=2 min 30 sec) improved SNR for rapid prostate HR-DWI, and achieved consistent and precise apparent diffusion coefficient (ADC) mapping compared to standard-resolution bipolar DWI (TA=5 min 50 sec).  

Impact: Eddy Current-Nulled Convex Optimized Diffusion Encoding combined with Random Matrix Theory-based denoising enables rapid high-resolution prostate DWI using fewer repetitions while maintaining the signal-to-noise ratio and robustness of apparent diffusion coefficient maps. This method could improve characterization of prostate cancer.

Keywords: Prostate, Prostate, prostate cancer, 0.55 T, low field, MRF, fingerprinting, synthesized contrast

Motivation: 0.55 T MRI scanners have lower fields inhomogeneities and bigger bore size when compared to higher fields, allowing to scan larger body habitus patients, and to perform MRI-guided biopsies.
 

Goal(s): To generate 1x1x3 mm³ T₁ and T₂ maps of the prostate and T₁ and T₂ weighted images with improved contrast from MRF at 0.55 T.

Approach: We use a 3D MRF-FISP sequence with Stack of Spirals acquisition and a low-rank denoising method.

Results: We show T₁ and T₂ maps and T₁ and T₂ weighted images and report on values for the prostate NPZ and NTZ of 5 subjects and for a biopsy-confirmed lesion.

Impact: Implementing prostate MR Fingerprinting at 0.55 T, allows multiparametric quantitative assessment of the gland while gaining advantages that 0.55 T scanners offer respect to higher field ones. This includes lower fields inhomogeneities, bigger bore size and a lower equipment cost.

Keywords: Prostate, Cancer

Motivation: Non-invasive and efficient diagnostic methods for prostate cancer are urgently needed to enhance patient experience and improve diagnostic accuracy.

Goal(s): To develop and validate a novel radial turbo spin-echo (rTSE) sequence for luminal water imaging (LWI) that reduces MRI scan times while maintaining image quality.

Approach: Employed a radial k-space trajectory for the rTSE sequence, optimized on volunteers, followed by paired comparison with the MESE sequence. Implemented spatial regularization to stabilize the T2 decay curve fitting.

Results: The rTSE sequence halved scan times without compromising image quality or diagnostic precision. Spatial regularization significantly improved the homogeneity and smoothness of LWF, demonstrating better outcomes.

Impact: The rTSE sequence enhances prostate MRI by cutting scan times and discomfort without losing diagnostic accuracy. Spatial regularization refines tissue analysis for earlier cancer detection and reduces noise for clearer luminal water fraction maps.

Keywords: Prostate, Cancer, prostate cancer, discordant radiology pathology

Motivation: To understand the risk of clinically significant prostate cancer (csPCa) in patients with negative biopsies for PIRADS categories 4 and 5 lesions, addressing a critical gap in clinical decision-making following discordant prostate MRI-biopsy findings.

Goal(s): To determine the prevalence of csPCa among patients with negative biopsy for PIRADS 4 or 5 lesions.

Approach: A multicenter retrospective study, utilizing Natural Language Processing (NLP) to analyze patient demographics, clinical, imaging and pathologic outcomes, followed by statistical analyses. 

Results: In 44% patients was found to have csPCa after initial discordant prostate MRI- biopsy.

Impact: This study underscores the high risk of csPCa in patients with initial negative biopsies for PIRADS 4 or 5 lesions, potentially guiding clinicians in patient management and informing follow-up strategies.

Keywords: Prostate, Prostate

Motivation: The clinical course of MR-visible Gleason 6 prostate cancer is unclear.

Goal(s): We studied patients with MR-visible prostate lesions scored as Gleason 6 after MR-guided and systematic biopsy.

Approach: We retrospectively analyzed the rate of Gleason grade upgrading in 95 men initially diagnosed with Gleason 6 prostate cancer in an MR-visible lesion who later underwent a second biopsy or prostatectomy.

Results: Over half of MR-visible Gleason 6 lesions were upgraded to Gleason 7 with a median time to upgrade of ~2 years. Neither PSA density nor ADC value predicted subsequent upgrade.

Impact: Gleason 6 prostate cancer that is MR-visible often harbors higher grade cancer. This argues for more aggressive monitoring or earlier intervention in these patients.

Keywords: Prostate, Prostate, Health disparity, perfusion analysis

Motivation: Race and ethnicity strongly impact the risk of prostate cancer, and understanding the impact of biological heterogeneity in patients from different racial/ethnic backgrounds is crucial for reducing the observed gaps in clinical outcomes.

Goal(s): To investigate potential differences in quantitative perfusion characteristics of prostate cancer between African American and White men.

Approach: After matching commonly known clinical risk factors, the quantitative DCE-MRI analysis was performed to assess differences in perfusion parameters of the pathology- and MRI-based lesions African American and White men.

Results: Notable differences between the two cohorts were observed in the K^trans of tumors with csPCa.

Impact: Considering race-specific perfusion characteristics can help in understanding biological factors of health disparity in prostate cancer.

Keywords: Prostate, Quantitative Imaging, Treatment response, tumors, radiotherapy, prostate

Motivation: Tumour heterogeneity can result in a spatial variation in response to radiation. While quantitative MRI (qMRI) shows promise in monitoring treatment response in prostate cancer (PCa), there remains an untapped potential for spatial response mapping to detect radioresistant tumour sub-regions suitable for early salvage therapy.

Goal(s): To assess the feasibility of treatment response mapping in a post-radiation therapy longitudinal qMRI PCa dataset.

Approach: Longitudinal qMRI parameter maps of 16 PCa patients were analysed using voxel-wise and region of interest (ROI) approaches.

Results: Voxel-wise analysis identified heterogeneity in treatment-related changes within PCa that would otherwise be concealed in ROI-based assessments.

Impact: Voxel-wise analysis of longitudinal qMRI parameter maps can detect radiation treatment response in sub-volumes of prostate cancer. Reliable detection and localisation of early treatment response provides an opportunity for adaptive or salvage therapies of treatment-resistant tumours.