Keywords: Liver, Fat, proton density fat fraction, quantitative, reproducibility, repeatability

Motivation: Performance assessment of PDFF in phantoms and in vivo, including linearity and bias, and reproducibility and repeatability, have largely focused between the range of 0-50%.

Goal(s): We analyzed PDFF performance in a two-site phantom study across the full 0-100% PDFF range.

Approach: We used commercially available quantitative 3D chemical-shift-encoded water-fat MRI pulse sequences across three vendors at 1.5T and 3T.

Results: Results demonstrate strong linearity and minimal bias {pooled slope and intercept for 1.5T=0.99 (95% CI: 0.981-0.997), 0.61 (0.17, 1.04); for 3T=1.00 (0.995, 1.005), 0.69 (0.39, 0.97)} of PDFF across 10 MRI systems.  Pooled reproducibility coefficient (RDC) across 30 phantom exams was 3.92%.

Impact: PDFF across the 0-100% range can be reliably estimated with minimal bias and strong linearity using current commercial offerings from MRI vendors at 1.5T and 3T, with intra-scanner repeatability coefficient<2% (in PDFF%) and inter-scanner, inter-site, and inter-vendor RDC<4% (in PDFF%).

Keywords: Endocrine, Aging, Obesity

Motivation: As cardiometabolic risk in obesity is associated with specific body composition types, we aim at deciphering age-related body composition changes in people with obesity.

Goal(s): To assess age-specific abdominal organ volume and proton density fat fraction (PDFF) in people with obesity and predict chronological age.

Approach: An nnU-Net-based automatic pipeline was used to segment abdominal organs. Machine-learning-based methods were applied to predict chronological age based on the organs' volumes and PDFF in chemical-shift encoding-based MRI.

Results: The best predictors for chronological age were increased visceral adipose tissue volume and elevated ectopic fat deposition in the paraspinal muscle, measured via proton density fat fraction.

Impact: Age-specific differences in volumes and PDFF of abdominopelvic fat depots, and ectopic fat in liver and two muscles were found in people with obesity using automated segmentation on quantitative chemical-shift encoding-based MRI scans.

Keywords: Liver, Tissue Characterization, normal values

Motivation: To fully exploit the clinical potential of T1 mapping in liver disease detection, normal values should be established.

Goal(s): We defined normal ranges for native hepatic T1 values using a 1.5T General Electric scanner.

Approach: MOLLI sequences were acquired in 100 healthy volunteers and native T1 values were quantified in the visible hepatic segments. 

Results: Segmental and global liver T1 values exhibited a good intra- and inter-observer reproducibility. A significant difference in the segmental T1 values was detected. Segmental and global T1 values were not associated with age and were comparable between males and females.

Impact: Liver T1  mapping is feasible and reproducible and the provided normal ranges may help to establish diagnosis and progression of various liver diseases.

Keywords: Liver, Quantitative Imaging

Motivation: Hepatic tissue architecture and water-fat content change concurrently with liver disease progression. Simultaneous measurement of water-specific T1 (T1-W) and proton density fat fraction (PDFF) can serve as a quantitative metric for assessment of liver disease.

Goal(s): To develop and validate a Look-Locker multi-echo Dixon (LLmDIXON) technique to simultaneously measure T1-W and PDFF in a single breath-hold.

Approach: Simultaneous T1-W and PDFF measurements were obtained using LLmDIXON and reference sequences in a phantom (0-40 % PDFF) and four volunteers (4.0-18.2% PDFF).

Results: The LLmDixon-based T1-W and PDFF values agreed with simulations and reference sequences in a phantom, and provided comparable PDFF values in volunteers.

Impact: LLmDixon provides simultaneous measurement of water-specific T1 and PDFF in a single 15s breath hold. This technique has the potential to characterize liver disease, where both cellular architecture and fat content can concurrently change as disease progresses.

Keywords: Liver, Liver, T1 mapping, hepatic steatosis

Motivation: In evaluating T1 values in patients with hepatic steatosis, it is necessary to investigate the effect of fat because MOLLI is sensitive to fat.

Goal(s): To elucidate the clinical importance of MOLLI T1 mapping of the liver using TE=1.8 (AIOP) sequence in daily practice.

Approach: In 122 patients with suspected liver diseases, MOLLI T1 mapping with TE=1.8 (AIOP) was compared with that with TE=1.3 (OP) and TE=2.4 (IP).

Results: The positive correlation with high correlation coefficient between T1 value of the liver in AIOP sequence and FIB-4 score was observed in patients with hepatic steatosis (PDFF ≥10%).

Impact: T1 mapping using AIOP sequence will be critical for assessing liver fibrosis in patients with hepatic steatosis since T1 mapping obtained by OP and IP sequences have risk of over- and under-estimation of T1 measurements.

Keywords: Liver, Quantitative Imaging, free-breathing liver R2∗ mapping;hepatic iron overload

Motivation: Existing liver iron quantification methods are inadequate for extreme iron deposition, hindering effective guidance for iron chelation therapy. 

Goal(s): Evaluate the practicality of a free-breathing, single-echo UTE sequence with varying echo times for multiple acquisitions in assessing severe hepatic iron overload.

Approach: A 3.0T UTE sequence with rigid-based motion correction was used to assess hepatic R2* in nine thalassemia patients, and compared with LIC from Ferriscan and R2* from a 1.5T GRE sequence. 

Results: UTE-R2* correlated well with GRE-R2* and Ferriscan-LIC, and could differ hepatic iron content in patients whose Ferriscan-LIC or GRE-R2* reach to upper limit.

Impact: An imaging strategy utilizing a free-breathing, single-echo UTE sequence with variable echo times for multiple acquisitions, combined with rigid-based motion correction, could be employed to evaluate extreme hepatic iron deposition.

Keywords: Lung, Lung, pulmonary nodules，Ultrashort Echo Time (UTE) Spiral-VIBE MR， Radiomics，Radiomics Stability

Motivation: This study aims to assess the efficacy of UTE-MRI in detecting lung nodules compared to CT and to evaluate the stability of radiomics features, along with the factors influencing them.

Goal(s): Through the advancement of UTE scanning technology, we strive to enable MRI to achieve lung nodule detection capability and stability on par with CT.

Approach: To facilitate the clinical integration of UTE technology for lung diseases, UTE scanning was conducted on patients presenting with lung nodules.

Results:  UTE-MRI demonstrates a high detection rate for lung nodules larger than 6 mm, and it exhibits a high level of stability in radiomics features.

Impact: Our study shows UTE showcasing a remarkable ability to detect lung nodules larger than 6 mm and maintain consistent radiomics features across repeated scans. UTE holds potential as a radiation-reducing alternative to CT for regularly monitored patients with lung nodules.

Keywords: Kidney, Kidney, Microstructure Imaging

Motivation: Diffusion-weighted (DW)-MRI may characterise renal cell carcinoma (RCC) by reflecting cellularity, but results using the apparent diffusion coefficient (ADC) model are inconclusive.

Goal(s): Use advanced modelling with VERDICT-MRI to characterise renal tissue in two different grades and subtypes of RCC, and compare performance to ADC.

Approach: Fit VERDICT and ADC models to DW-MRI data from two patients and compare performance in terms of accuracy of fitted signal and parameter estimates.

Results: The VERDICT model captures the DW-MRI signal more accurately than ADC. It discriminates between tissue types, and shows high cellularity and low vasculature in the grade 3 tumour, agreeing with independent CT.

Impact: We show that VERDICT-MRI can be used to accurately characterise tumour and benign tissue microstructure in two patients with RCC of different grade and subtype, improving performance over ADC and reflecting histological tissue properties such as cellularity and vasculature.

Keywords: Kidney, Kidney, Amide proton transfer; renal malignancies; Intravoxel incoherent motion

Motivation: Amide proton transfer (APT) imaging studies are gradually expanding to the body, with few applications in renal diseases and a lack of tumor studies.

Goal(s): In the present study, we aimed to investigate the ability of APT and voxel-wise intravoxel incoherent motion (IVIM) imaging to detect renal malignancies. 

Approach: We preliminarily analyzed the ability of APT imaging to discriminate malignant tumors from normal renal tissues, combined with each parameter of IVIM imaging, which has high diagnostic efficacy.

Results: The results showed that APT imaging was feasible and superior to IVIM imaging in discriminating renal malignant tumors from normal renal tissues.

Impact: APT imaging has potential clinical applications in diagnosing of renal malignancies and provides a reference for subsequent accurate studies of APT imaging of renal tumors.

Keywords: Liver, Diabetes, Bariatric, Pre-Diabetes, Liver, Pancreas, Spleen

Motivation: Bariatric surgery is evaluated by weight loss and diabetes remission, but the mechanism of the latter is unclear. 

Goal(s): Use MRI to quantify changes in liver, pancreas and subcutaneous adipose tissue (SAT). 

Approach: Multiparametric MRI of fat fraction (FF), T₂*, volume, T₁ and T₂ at four timepoints before and after bariatric surgery. 

Results: Significant reduction in liver FF from baseline to 6-weeks, and between post-VLCD and 6-weeks, and liver volume from baseline to subsequent time points. Compared to baseline a significant increase in liver T₂* at 6-weeks, reduction in liver T₁ at 6-weeks and 6-months, and decrease in SAT at 6-months

Impact: Multiparametric MRI assessment of changes in liver and pancreas fat, volume and T₁, T₂* and T₂ relaxometry, as well as subcutaneous volume associated with bariatric surgery may serve as markers for longitudinal and cross-sectional assessment of patients. 

Keywords: Breast, Phantoms, Quantitative, fat fraction

Motivation: Operator-independent quantification of breast density with proton density fat fraction (PDFF) may be more accurate than conventional T1-weighted imaging-based methods, which are limited by the partial volume effect (PVE) and require significant user input.

Goal(s): We aimed to assess the accuracy of PDFF against fuzzy clustering (FCM) of T1-weighted images.

Approach: Five phantoms representative of different breast compositions were imaged and the breast density calculated with both methods was compared to the known density.

Results: PDFF demonstrated improved accuracy compared to FCM of T1-weighted images. FCM-derived density was more sensitive to the partial volume effect and dependent on the bias correction algorithm.

Impact: The improved accuracy and comparative robustness of proton density fat fraction (PDFF) suggests it is a more reliable and operator-independent approach to breast density calculation than fuzzy clustering. This is particularly important when assessing longitudinal changes to breast structure.

Keywords: Liver, Inflammation, Diffuse liver disease, multifrequency MRE, 3D MRE

Motivation: Additional viscoelastic parameters measured using 3D multifrequency MRE have been reported to detect inflammation in the liver. However, a clinical cohort with multiple etiologies has not been well-studied.

Goal(s): Our goal was to determine the role of 3D multifrequency MRE for staging hepatic inflammation in diffuse liver disease with various etiologies.

Approach: Viscoelastic parameters were derived from 3D MRE with low, medium and high vibration frequencies, and compared with histological assessment.

Results: The moduli |G*|, G’ and G” and the exponent of power law γ were found to be associated with inflammation.

Impact: Three-dimensional multifrequency MRE, with its ability to provide additional viscoelastic parameters, could be a powerful tool for the non-invasive detection of inflammation activity in patients with diffuse liver disease.

Keywords: Liver, Quantitative Susceptibility mapping

Motivation: Fibrotic liver, a condition that may cause cirrhosis if untreated, often contains both paramagnetic iron and diamagnetic collagen. While quantitative susceptibility mapping (QSM) calculates the voxel-wise tissue susceptibility, it cannot distinguish the competing effect of iron and collagen within a voxel.

Goal(s): The purpose of this work is to identify sub-voxel paramagnetic and diamagnetic susceptibility sources within the liver and spleen.

Approach: For this purpose, we applied the DECOMPOSE-QSM method to abdominal 1.5T MR images of patients with various levels of iron overload.

Results: The resulting paramagnetic and diamagnetic susceptibility maps demonstrated improved contrast compared to bulk susceptibility maps provided by QSM.

Impact: Identifying sub-voxel paramagnetic and diamagnetic sources within the liver through DECOMPOSE-QSM can facilitate the diagnosis of conditions such as liver fibrosis and hepatic iron overload.

Keywords: Breast, Breast, multimodal; MUSE; MAGIC; IDEAL-IQ; HER-2

Motivation: Human epidermal growth factor receptor-2(HER-2) was a proto-oncogene, and its overexpression was closely associated with the development and prognosis of breast cancer.

Goal(s): To investigate predictive value of intratumoral and peritumoral multimodal magnetic resonance imaging (MRI) before surgery for the expression level of HER-2 in breast cancer.

Approach: The parameters, including apparent diffusion coefficient (ADC), tissue-diffusivity (Dt), pseudo-diffusivity (Dp), perfusion fraction(f), relaxation rate(R2*), fat-fraction (FF), the relaxation value  longitudinal relaxation time(T1),  transverse relaxation time(T2) and proton density(PD) were used to predict the expression level of HER-2 in breast cancer.

Results: MUSE-Dt-peritumoral predicted HER-2 with the highest AUC(0.724, P=0.017).

Impact: There were few studies involving intratumoral and peritumoral multimodal MRI to predict HER-2 in breast cancer. The result was that peritumoral parameters had a momentous part in predictive performance beyond expectation, especially non-invasive techniques which were easy to implement clinically.

Keywords: Liver, Metabolism, Lipid composition; J-difference-edited-MRS

Motivation: Hepatic lipid composition is important for diagnosis and prognosis of many hepatic diseases and for studying lipid metabolism. 

Goal(s): This study aimed to apply J-difference-edited-MRS (JDE-MRS) for better measurement of hepatic lipid composition and evaluated its effectiveness in detecting lipid profile changes among metabolic disorders.

Approach: Hepatic lipid composition was measured and compared among healthy, NAFLD and T2DM human subjects using JDE-MRS under 3T, as well as among normal, obese and T2DM rat models using conventional MRS under 7T.

Results: The JDE-MRS application in human liver is reliable and the results shows differences between different groups, with similar results in rats.

Impact: This study demonstrates the feasibility of applying JDE-MRS in human liver, which can be used to quantify hepatic unsaturated lipid profile and can provide a reliable biomarker for clinical investigations of lipid metabolism in hepatic diseases.

Keywords: Screening, Low-Field MRI, Body Composition

Motivation: Body composition MRI is well established at 1.5T. However there is limited work at low-field where there is growing interest, particularly with increased accessibility of ultra-wide bore systems.

Goal(s): Demonstrate the feasibility of body composition MRI on a 0.55T (80cm) system, and present optimised sequence parameters suitable for large-scale studies.

Approach: Dixon and liver T1 and T2*/PDFF scans were optimised iteratively by scanning subjects with a range of BMIs at 0.55T using ultra-flexible receive-array coils.

Results: Body composition MRI has been demonstrated on a commercial 0.55T system. Image quality was sufficient for utilisation of an analysis pipeline established for higher field.

Impact: Body composition MRI is feasible on a commercial 0.55T system, providing motivation for further protocol development. This generation of scanner presents an opportunity for more affordable and accessible MRI, with a wide bore suitable for imaging larger patients and participants.

Keywords: Breast, Breast

Motivation: Breast MRI is increasingly used for diagnosis and high-risk screening in patients with silicone breast implants, a common aesthetic procedure, but silicone-specific sequences lengthen and complicate protocols.

Goal(s): We aim to demonstrate simultaneous water-fat-silicone separation with T2-weighting, and improved contrast between fat and silicone. 

Approach: We propose Dual-Interval Echo-Time (DIET) preparation to provide T2-weighting with reduced fat signal, and multi-point species separation with 5 gradient echoes at each spin-echo. 

Results: We demonstrate robust water-fat-silicone separation (WFSS) and improved control of T2-weighting in water, and the contrast between fat and silicone.

Impact: We have combined DIET Fast Spin Echo with multi-echo water-fat-silicone separation to enable T2-weighted imaging for subjects with silicone breast implants.  This may allow improved evaluation of breast tissue, as well as assessment of complications with implants.

Keywords: Endocrine, Body, Fat Water Imaging

Motivation: The study is driven by the need to accurately quantify abdominal fat, particularly visceral fat, to better understand its link with metabolic diseases

Goal(s): This research aims to develop a robust, automated 3D segmentation method for distinguishing and quantifying Subcutaneous and Visceral Fat from volumetric fat-water MRI images.

Approach: Utilizing Fat-Water Imaging combined with 3D whole volume segmentation and morphology provides improved quantification.

Results: The new method yielded more reliable and consistent fat compartment segmentation across subjects, outperforming the prior 2D segmentation techniques and showing promise for aiding the study of metabolic disorders.

Impact: The study's automated 3D Fat-Water image segmentation technique aids the assessment of abdominal fat, enabling clinicians and researchers to efficiently study and evaluate metabolic disease risk and progression.

Keywords: Cancer, Cancer, Clear Cell Renal Cell Carcinoma

Motivation: To develop targeted therapies for Clear Cell Renal Cell Carcinoma (ccRCC).

Goal(s): Investigation of metabolic activity in von Hippel-Lindau (VHL) patient derived renal tumor cells using NMR based stable isotope tracing to develop targeted tumor therapies. 

Approach: Cultured VHL patient derived renal tumor cells (UOK270 and UOK 366) were harvested and extracted upon 24 h of [U-¹³C] Glucose tracing and analyzed using NMR based stable isotope Resolved Metabolomics (SIRM).

Results: After 24 h of [U-¹³C] Glucose tracing, we determined the relative levels of ¹³C incorporation in Glycolysis and (Tri Carboxylic Acid) TCA cycle intermediates in UOK 270 and UOK366 using NMR based SIRM.

Impact: This is the first-time investigation of metabolic activity in VHL patient derived renal tumor cells generated in house (UOK270 and UOK366) impacting on ccRCC treatment development.

Keywords: Prostate, Prostate

Motivation: Validate the consistency and reliability of Hybrid Multidimensional MRI (HM-MRI) through repeatability assessments.

Goal(s): Evaluate the repeatability of HM-MRI in prostate tissue characterization and its diagnostic accuracy for prostate cancer.

Approach: Our approach consists on performing dual HM-MRI scans with a one-week interval to assess measurement consistency and diagnostic accuracy of HM-MRI biomarkers.

Results: The results indicate high reproducibility of HM-MRI metrics, evidenced by strong inter-class correlation coefficients, with consistent tissue composition measurements across initial and repeat scans, and robust diagnostic performance of HM-MRI parameters in prostate cancer detection.

Impact: The findings of this study highlights the potential of HM-MRI as a reliable tool for prostate cancer diagnosis, paving the way for non-invasive clinical applications and inspiring further research into its utility in other diagnostic imaging techniques.