4D-MRI at 0.55T for internal target volume delineation in liver radiation therapy planning.

Background: Low-field MRI provides superior soft-tissue contrast compared to CT while costing significantly less than high-field MRI, which makes it a more accessible option for MRI-guided radiation therapy planning. Four-dimensional MRI (4D-MRI) is a technique that has been increasingly adopted clinically for internal target volume (ITV) delineation in free-breathing liver radiotherapy planning, and it requires high spatial resolution and accurate respiratory phase differentiation to enable precise dose planning. The feasibility of 4D-MRI at low-field strength, specifically at 0.

Correction: Chen et al. Multivariate Framework of Metabolism in Advanced Prostate Cancer Using Whole Abdominal and Pelvic Hyperpolarized 13C MRI-A Correlative Study with Clinical Outcomes. 2025, , 2211.

In the original publication [...

Multivariate Framework of Metabolism in Advanced Prostate Cancer Using Whole Abdominal and Pelvic Hyperpolarized C MRI-A Correlative Study with Clinical Outcomes.

Most of the existing hyperpolarized (HP) C MRI analyses use univariate rate maps of pyruvate-to-lactate conversion (k), and radiomic-style multiparametric models extracting complex, higher-order features remain unexplored. To establish a multivariate framework based on whole abdomen/pelvis HP C-pyruvate MRI and evaluate the association between multiparametric features of metabolism (MFM) and clinical outcome measures in advanced and metastatic prostate cancer. Retrospective statistical analysis was performed on 16 participants with metastatic or local-regionally advanced prostate cancer prospectively enrolled in a tertiary center who underwent HP-pyruvate MRI of abdomen or pelvis between November 2020 and May 2023.

Regional quantification of metabolic liver function using hyperpolarized [1-C] pyruvate MRI.

Assessment of liver function is essential before partial hepatectomy to predict the risk of post hepatectomy liver failure, a severe and life-threatening complication. Traditional methods have focused on expected future liver remnant (FLR) volume estimation. However, liver volume does not always correlate with function.

Multi-contrast 4DMR via MR multitasking: Early clinical experience and implication for liver stereotactic body radiation therapy.

Background: Liver tumors have low contrast on 4DCT. A novel Multitasking (MT)MR imaging technique has been implemented on the MR simulator, providing both T1 and T2-weighted 4DMR images in a single 8-min free-breathing scan for better tumor delineation and motion evaluation. This study reports our early clinical experience of MTMR regarding tumor visibility, motion characteristics, and resultant dosimetry compared to post-contrast 4DCT for liver SBRT.

A data-driven approach for improved quantification of in vivo metabolic conversion rates of hyperpolarized [1-C]pyruvate.

Purpose: Accurate quantification of metabolism in hyperpolarized (HP) C MRI is essential for clinical applications. However, kinetic model parameters are often confounded by uncertainties in radiofrequency flip angles and other model parameters.

Methods: A data-driven kinetic fitting approach for HP C-pyruvate MRI was proposed that compensates for uncertainties in the B field.

Advanced Restriction Imaging and Reconstruction Technology for Prostate Magnetic Resonance Imaging (ART-Pro): A Study Protocol for a Multicenter, Multinational Trial Evaluating Biparametric Magnetic Resonance Imaging and Advanced, Quantitative Diffusion Magnetic Resonance Imaging for the Detection of Prostate Cancer.

Multiparametric magnetic resonance imaging (mpMRI) is strongly recommended by current clinical guidelines for improved detection of clinically significant prostate cancer (csPCa). However, the major limitations are the need for intravenous (IV) contrast and dependence on reader expertise. Efforts to address these issues include use of biparametric magnetic resonance imaging (bpMRI) and advanced, quantitative magnetic resonance imaging (MRI) techniques.

Detection of early-stage NASH using non-invasive hyperpolarized C metabolic imaging.

Non-alcoholic steatohepatitis (NASH) is characterized from its early stages by a profound remodeling of the liver microenvironment, encompassing changes in the composition and activities of multiple cell types and associated gene expression patterns. Hyperpolarized (HP) C MRI provides a unique view of the metabolic microenvironment, with potential relevance for early diagnosis of liver disease. Previous studies have detected changes in HP C pyruvate to lactate conversion, catalyzed by lactate dehydrogenase (LDH), with experimental liver injury.

Precision and Test-Retest Repeatability of Stiffness Measurement with MR Elastography: A Multicenter Phantom Study.

Background MR elastography (MRE) has been shown to have excellent performance for noninvasive liver fibrosis staging. However, there is limited knowledge regarding the precision and test-retest repeatability of stiffness measurement with MRE in the multicenter setting. Purpose To determine the precision and test-retest repeatability of stiffness measurement with MRE across multiple centers using the same phantoms.

Distinguishing metabolic signals of liver tumors from surrounding liver cells using hyperpolarized C MRI and gadoxetate.

Purpose: To use the hepatocyte-specific gadolinium-based contrast agent gadoxetate combined with hyperpolarized (HP) [1- C]pyruvate MRI to selectively suppress metabolic signals from normal hepatocytes while preserving the signals arising from tumors.

Methods: Simulations were performed to determine the expected changes in HP C MR signal in liver and tumor under the influence of gadoxetate. CC531 colon cancer cells were implanted into the livers of five Wag/Rij rats.

Hyperpolarized [1- C] pyruvate MRSI to detect metabolic changes in liver in a methionine and choline-deficient diet rat model of fatty liver disease.

Purpose: Nonalcoholic fatty liver disease is an important cause of chronic liver disease. There are limited methods for monitoring metabolic changes during progression to steatohepatitis. Hyperpolarized C MRSI (HP C MRSI) was used to measure metabolic changes in a rodent model of fatty liver disease.

Per-patient Negative Predictive Value of the CT and MRI Liver Imaging Reporting and Data System Version 2018 Treatment Response Algorithm for Hepatocellular Carcinoma.

Background The Liver Imaging Reporting and Data System version 2018 (LI-RADS) treatment response algorithm (TRA) is a high-specificity, lower-sensitivity grading system to diagnose hepatocellular carcinoma (HCC) and recurrence after local-regional therapy. However, the emphasis on specificity can result in disease understaging, potentially leading to poorer posttransplant outcomes. Purpose To determine the negative predictive value (NPV) of pretransplant CT and MRI assessment for viable HCC on a per-patient basis using the LI-RADS TRA, considering explant pathology as the reference standard.

Hyperpolarized C Metabolic MRI of Patients with Pancreatic Ductal Adenocarcinoma.

Background: Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related death in the United States. However, early response assessment using the current approach of measuring changes in tumor size on computed tomography (CT) or MRI is challenging.

Purpose: To investigate the feasibility of hyperpolarized (HP) [1-C]pyruvate MRI to quantify metabolism in the normal appearing pancreas and PDA, and to assess changes in PDA metabolism following systemic chemotherapy.

Imaging the Bacterial Cell Wall Using -Acetyl Muramic Acid-Derived Positron Emission Tomography Radiotracers.

Imaging infections in patients is challenging using conventional methods, motivating the development of positron emission tomography (PET) radiotracers targeting bacteria-specific metabolic pathways. Numerous techniques have focused on the bacterial cell wall, although peptidoglycan-targeted PET tracers have been generally limited to the short-lived carbon-11 radioisotope ( = 20.4 min).

Chemoenzymatic Syntheses of Fluorine-18-Labeled Disaccharides from [F] FDG Yield Potent Sensors of Living Bacteria .

Chemoenzymatic techniques have been applied extensively to pharmaceutical development, most effectively when routine synthetic methods fail. The regioselective and stereoselective construction of structurally complex glycans is an elegant application of this approach that is seldom applied to positron emission tomography (PET) tracers. We sought a method to dimerize 2-deoxy-[F]-fluoro-d-glucose ([F]FDG), the most common tracer used in clinical imaging, to form [F]-labeled disaccharides for detecting microorganisms based on their bacteria-specific glycan incorporation.

A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT.

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted.

Chemoenzymatic syntheses of fluorine-18-labeled disaccharides from [ F]FDG yield potent sensors of living bacteria .

Chemoenzymatic techniques have been applied extensively to pharmaceutical development, most effectively when routine synthetic methods fail. The regioselective and stereoselective construction of structurally complex glycans is an elegant application of this approach, that is seldom applied to positron emission tomography (PET) tracers. We sought a method to dimerize 2-deoxy-[ F]-fluoro-D-glucose ([ F]FDG), the most common tracer used in clinical imaging, to form [ F]-labeled disaccharides for detecting microorganisms based on their bacteria-specific glycan incorporation.

Liver Fibrosis, Fat, and Iron Evaluation with MRI and Fibrosis and Fat Evaluation with US: A Practical Guide for Radiologists.

Quantitative imaging biomarkers of liver disease measured by using MRI and US are emerging as important clinical tools in the management of patients with chronic liver disease (CLD). Because of their high accuracy and noninvasive nature, in many cases, these techniques have replaced liver biopsy for the diagnosis, quantitative staging, and treatment monitoring of patients with CLD. The most commonly evaluated imaging biomarkers are surrogates for liver fibrosis, fat, and iron.

Changes in abdominal adipose tissue depots assessed by MRI correlate with hepatic histologic improvement in non-alcoholic steatohepatitis.

Background & Aims: Non-alcoholic steatohepatitis (NASH) is prevalent in adults with obesity and can progress to cirrhosis. In a secondary analysis of prospectively acquired data from the multicenter, randomized, placebo-controlled FLINT trial, we investigated the relationship between reduction in adipose tissue compartment volumes and hepatic histologic improvement.

Methods: Adult participants in the FLINT trial with paired liver biopsies and abdominal MRI exams at baseline and end-of-treatment (72 weeks) were included (n = 76).