Keywords: Perfusion, Contrast Mechanisms, breast tumor; dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)

Motivation: Breast MRI plays a vital role in early breast cancer screening, staging, and surgical guidance. The core technology used in breast MRI is DCE-MRI.

Goal(s): This study aims to assess the effectiveness of using the GRASP sequence in distinguishing highly malignant breast lesions.

Approach: We utilized the GRASP sequence, which offers high temporal resolution, to compare and analyze the microvascular characteristics of benign and malignant breast lesions.

Results: We found that K_ep was significantly higher in malignant lesions compared to benign lesions, suggesting a potential relationship between the abundant blood supply and high wall permeability observed in malignancies.

Impact: The GRASP dynamic enhancement technique provides both morphological and hemodynamic characteristics of breast lesions, aiding in the differentiation of high-grade malignancies.

Keywords: Pancreas, Diabetes

Motivation: The diabetes-related pancreatic changes on MRI remain to be fully elucidated. 

Goal(s): Our goal was to determine characteristic imaging findings of the pancreas on MRI in patients with type 1 diabetes (T1D) and type 2 diabetes (T2D). 

Approach: Seven T1D patients and fifty-four T2D patients were imaged using multiparametric pancreatic MRI including T1 map, PDFF map, ADC map and cine-dynamic MRCP, and were compared to control patients.

Results: T1D patients had reduced pancreatic size, increased pancreatic T1 and ADC values, and decreased pancreatic juice flow on cine-dynamic MRCP. T2D patients had increased pancreatic PDFF.

Impact: Multiparametric MRI provided valuable information on pancreatic changes in both T1 and T2 diabetes and may be useful for assessing pancreatic endocrine and exocrine insufficiency and pancreatic pathological changes in patients with diabetes.

Keywords: Pancreas, Quantitative Imaging, Acquisition & Reconstruction

Motivation: T₁ mapping provides valuable insights for the assessment of pancreatic diseases which might be challenging to evaluate if only based on qualitative MRI.

Goal(s): Not only a high-resolution, fast T₁ mapping method of the entire pancreas remains a challenge, but also a technique for water T₁ mapping since the T₁ is biased in the presence of fat.

Approach: This work proposes a high-resolution, rapid, continuous inversion-recovery Look-Locker method combining a spiral read out with Dixon and a dictionary-based processing for water T₁ mapping. 

Results: The entire pancreas is scanned within 24 slices, distributed in 3 breath-holds of 12s each.

Impact: The present work proposes a high-resolution water T₁ mapping methodology of the whole pancreas: 24 slices (2x2x5mm³) in 3 short breath-holds of 12s. The proposed method aims to support the fast assessment of diseases in the entire pancreas.

Keywords: Liver, Fat, non-alcoholic fatty liver disease; non-alcoholic steatohepatitis

Motivation: This study aims to assess the alterations in skeletal muscle parameters in patients with histologically confirmed NAFLD.

Goal(s): Find a non-invasive method for the diagnosis of NASH from NAFLD.

Approach: The data were analyzed using SPSS 26.0 statistical software.

Results: Our findings revealed a positive correlation was observed between NAS scores and the FIR of MF muscle at the L3 level. Remarkably, MF muscle fat infiltration and ALT emerged as independent risk factors for NASH. Moreover, the integration of laboratory indices and radiological parameters in a combined model shows promising potential for the diagnosis of NASH.

Impact: This study has revealed a profound association between PVM muscle radiological parameters and the severity of NAFLD and provided novel avenues for the diagnosis of NASH.

Keywords: Endocrine, Diabetes

Motivation: GLP-1 receptor agonists have shown favorable effects in improving obesity and ectopic fat deposition in type 2 diabetes patients. MRI-PDFF can serve as a tool for continuous, dynamic assessment of lipid content changes in patients.

Goal(s): Dynamic monitoring of fat content and lipid deposition changes in type 2 diabetes obese patients receiving glucagon-like peptide-1 receptor agonist treatment using MRI-PDFF.

Approach: 21 male diabetic patients received 3-month treatment: semaglutide (n=12) or loxenatide (n=9). Clinical data collected, pre/post 3.0T MRI scans (T1WI, T2WI, MRI-PDFF) measured fat.

Results: The semaglutide group showed significant fat reduction in multiple organs, while the loxenatide group reduced pancreatic fat fraction.

Impact: Semaglutide effectively controls blood glucose and body weight in type 2 diabetes obese patients. It also significantly reduces SAT and VAT while alleviating ectopic fat deposition. MRI-PDFF represents a non-invasive tool for continuous assessment of lipid content changes following treatment.

Keywords: Liver, Quantitative Susceptibility mapping, Type 2 Diabetes Mellitus, Hepatic iron deposition

Motivation: The hepatic iron deposition in Type 2 Diabetes Mellitus (T2DM) patients could affect insulin resistance and glucose production. The R2*-based method for measuring iron content can be affected by factors like fat tissue and background magnetic fields.

Goal(s): the study employed QSM method, which is insensitivity to the above confounder, to evaluate glucose dysfunction in T2DM.

Approach: Hepatic R2* and QSM values were measured in 11 T2DM patients, and were correlated with glucose tolerance.

Results: A negative correlation between QSM values and the insulin β-cells dysfunction was found, whereas R2* values did not show any significant correlation.

Impact: Hepatic Quantitative Susceptibility Mapping may serve as a predictor of glucose metabolism dysfunction in patients with Type 2 Diabetes Mellitus and has shown to be more effective than hepatic R2* for this purpose.

Keywords: Liver, Elastography, heterogeneity, MASLD

Motivation: Hepatic fibrosis, despite traditionally viewed as a diffuse occurrence, has been shown to vary spatially with disease progression. 

Goal(s): MR elastography (MRE) measures mechanical properties and their spatial variations can potentially provide holistic insights into tissue inhomogeneity.

Approach: Twenty-five rats based a metabolic dysfunction associated steatotic liver disease (MASLD) model monthly underwent MRE to investigate tissue inhomogeneity during cirrhosis development. 

Results: Results demonstrated increases in both microscopic and macroscopic inhomogeneities with disease progression. In cirrhotic livers, while mean MRE measurements correlated subtly with histological fibrosis and portal pressure, tissue heterogeneity presented stronger associations. Liver tissue heterogeneity is a complementary predictor of disease progression.

Impact: Assessing liver tissue heterogeneity via 3D vector MR elastography could enhance disease progression monitoring in chronic liver diseases and potentially predict clinically significant outcomes, offering a more comprehensive diagnostic approach than traditional mean liver stiffness and loss modulus measurements alone.
 

Keywords: Pancreas, Pancreas, Reproducibility, Repeatibility

Motivation: Determination of repeatability and reproducibility is vital to interpreting and determining measurable change of intra organ fat, specifically in small organs like the pancreas.

Goal(s): The goal of this study is to determine if intra-user repeatability and inter-user reproducibility coefficients of manually drawn ROIs on pancreatic fat.  

Approach: The approach of this study was to compare manually drawn ROIs within the pancreas between two users and within a single user.

Results: Results indicate that repeatability and inter-user reproducibility of manually drawn ROIs to determine the MRI measured pancreatic fat fraction were consistent within and across users.

Impact: The repeatability and inter-user reproducibility of manually drawn ROIs to determine the MRI measured pancreatic fat fraction yielded consistent measures both within and across users. 

Keywords: Liver, Liver

Motivation: Recent reports have shown a strong correlation between tissue water diffusivity and liver elasticity.

Goal(s): The aim to this study was to compare the performance of DW MRI-based virtual shear modulus (µ_Diff) and liver stiffness (LS) measured using US shear-wave elastography (SWE) for staging liver fibrosis.

Approach: We retrospectively analyzed µ_Diff and LS on the right liver lobe in 124 patients.

Results: Our results showed the area under the curve of LS was significantly higher than that of µ_Diff (0.96 vs. 0.87, P<0.05) for advanced fibrosis. However, no significant difference was found between LS and µ_Diff (0.88 vs. 0.79, P>0.05) for significant fibrosis.

Impact: Although DW MRI-based virtual shear modulus showed significant correlation with the histologic stages of fibrosis, it was inferior than liver stiffness measured using US shear-wave elastography for staging liver fibrosis.

Keywords: Liver, Liver

Motivation: Exploring changes in liver fat content in athletes and its role in predicting late gadolinium enhancement (LGE)  of myocardium

Goal(s): To use magnetic resonance imaging-proton density fat fraction(MRI-PDFF)  for the quantization of the liver fat content and prediction of LGE in athletes. 

Approach: Recruitment of athletes and controls for cardiac magnetic resonance(CMR) examination, analysis of liver fat content using MRI-PDFF, and application of logistic regression to construct predictive models for LGE.

Results: The liver fat content and mean liver fat fraction were altered in athletes compared with controls. Hepatic fat content can effectively predict LGE after excessive exercise.

Impact: The study advanced sports cardiology by identifying hepatic fat content as emerging indicators for predicting LGE in athletes, enhancing training strategies and early detection of myocardial fibrosis.

Keywords: Liver, Liver

Motivation: Expanding hepatic 3D MRE to wide-bore low field MR systems (B₀ ≤ 1.0T) can serve as a means of accommodating liver patients with high BMI and/or claustrophobia such as metabolic dysfunction-associated fatty liver disease (MAFLD) patients.

Goal(s): Demonstrate the feasibility of 3D MRE at 0.55T in healthy volunteers.

Approach: 5 healthy volunteers were scanned at 60Hz mechanical excitation with a Hadamard-encoded 3D MRE sequence at 0.55T and were also scanned with a reference 3D MRE sequence at 3T for comparison.

Results: Bland-Altman analysis demonstrated good agreement between the biomechanical parameters retrieved at 0.55T and 3T.

Impact: We demonstrated the feasibility of hepatic 3D MRE at 0.55T in healthy volunteers, which paves the pathway for an MRE clinical study in MAFLD patients to evaluate clinical added value.

Keywords: Liver, Quantitative Imaging, PDFF, MASH, NASH, MASLD, NAFLD, cT1

Motivation:  To address the pressing need for non-invasive diagnosis of metabolic dysfunction-associated steatohepatitis (MASH).

Goal(s): To evaluate the potential of proton-density fat-fraction (PDFF), corrected T1 (cT1), liver enzymes, and fibrosis scores to assist in the diagnosis of MASH.

Approach: The study included study participants with obesity and at risk for MASH, undergoing bariatric surgery with intraoperative liver biopsy. Potential predictors and predictor combinations were evaluated as classifiers for MASH and steatosis.

Results: PDFF distinguished MASH from non-MASH (AUC=0.85; 95%CI 0.79-0.91, p<0.0001). A cutoff of PDFF≥13.9% detected MASH with 90% specificity and 59% sensitivity. Neither cT1, liver enzymes, nor fibrosis scores significantly improved diagnostic performance.

Impact: Our results suggest that PDFF alone may be sufficient for non-invasive detection of metabolic dysfunction-associated steatohepatitis (MASH). This novel use case for an established method has the potential to transform the diagnostic approach to MASH which currently necessitates invasive biopsy.

Keywords: Liver, Liver

Motivation: Steatosis is the histopathologic hallmark of NAFLD. Liver histology is currently the standard for hepatic steatosis diagnosis, which is invasive. Several MRI methods have been validated to accurately measure hepatic fat content. 

Goal(s): To evaluate diagnostic performance of different hepatic fat quantification methods.

Approach: We compared hepatic fat content calculated by Dixon MRI and MRS with histology results as reference. 

Results: The outcomes show that the fat fraction measured by these two methods highly correlated with steatosis degrades measured by histology. Compared with MRS, fat fraction calculated by Dixon MRI performed better diagnostic capacity in hepatic steatosis.

Impact: Our study demonstrates that the Dixon-based method outperforms the MRS. The use of whole liver automatic segmentation improves diagnostic efficiency, and its performance is comparable to the ROI-based method, making it a promising hepatic fat fraction detection approach in clinic.

Keywords: Liver, Liver

Motivation: UTE-MT is suggested to indirectly assess macromolecular contents in both short and long T2 tissues, which may have the potential to assess non-alcoholic fatty liver disease (NAFLD).

Goal(s): To utilize the UTE-MT technique to assess the patients with NAFLD.

Approach: A total of 40 subjects were recruited (20 with NAFLD and 20 without NAFLD) and underwent UTE-MT scans on a 3T MRI scanner.

Results: The liver UTE-MTR value of NAFLD patients was significantly lower than that of normal ones (P<0.001). The ROC analysis between NAFLD patients and normal controls showed a high AUC value of 0.953.

Impact: The UTE-MT technique can be utilized for the assessment of macromolecular content changes in NAFLD livers. The UTE-MTR may serve as a promising biomarker for screening patients with NAFLD.

Keywords: Liver, Elastography

Motivation: MRE-assessed liver stiffness, MRI-derived fat fraction, AST, and FIB-4 are promising predictors for identifying at-risk MASH, which is defined as MASH with fibrosis stage 2 or higher. Some investigators have also proposed an additional criterion, NAS ≥ 4 with at least 1 point in each category.

Goal(s): Assess prediction models for diagnostic accuracy in identifying at-risk MASH under both definitions.

Approach: AUC and its 95% confidence intervals were used to assess the overall diagnostic accuracy.

Results: The additional criterion influenced the performance of prediction models, but liver stiffness remains the most reliable single predictor among non-invasive biomarkers.

Impact: At-risk MASH is defined as a MASH diagnosis with fibrosis stage ≥2. Adding a criterion of NAS≥4 with ≥1 point in each category impacts diagnostic accuracy but liver stiffness remains the most reliable single predictor.

Keywords: Endocrine, Fat, brown adipose tissue

Motivation: The recent discovery of brown adipose tissue (BAT) in adults presents new approaches for treating metabolic disorders. 

Goal(s): Noninvasive methods for distinguishing between BAT and white adipose tissue (WAT) are still under the exploration. 

Approach: In this study, histogram features of human BAT and WAT were extracted using fat fraction (FF) maps that generated from the modified Dixon (mDIXON) technique. The features were subsequently analyzed and differentiated between the two types of adipose tissue.

Results: The results indicated that 16 out of 18 extracted features were statistically significant. Furthermore, in the reproducibility study, four features exhibited strong reproducibility.

Impact: This study demonstrated the feasibility of differentiating BAT and WAT by using noninvasive MRI approach. The mDIXON technique allows for BAT's quantification, providing a convenient way for researching BAT's correlation with certain metabolic disorders.