The Value of MR-DWI and T1 Mapping in Indicating Radiation-Induced Soft Tissue Injury

T1/T2 mapping as a non-invasive method for evaluating liver fibrosis based on correlation of biomarkers: a preclinical study

BACKGROUND

Given the inherent limitations of invasive biopsy and the insufficient accuracy of liver-related serum biomarkers, there is an urgent need for the development of reliable, non-invasive imaging techniques for the diagnosis of liver fibrosis. This study aims to investigate the correlation between magnetic resonance imaging (MRI) T1/T2 mapping sequences and biomarkers of collagen deposition and ongoing systemic inflammation, and to evaluate the potential of T1/T2 mapping as a non-invasive method for the accurate diagnosis of liver fibrosis.

METHODS

A mouse model of carbon tetrachloride (CCl4)-induced liver fibrosis was established and T1/T2 mapping were performed at different weeks of treatment. The histopathological analysis, collagen quantification, and inflammatory factors measurements (IL-1, IL-6, TNF-α) were conducted to correlate MRI parameters with collagen deposition and inflammation. Statistical analysis was performed using IBM SPSS Statistics (version 22.0, Chicago, IL, USA) and Origin 2018 (OriginLab Corporation, Northampton, MA, USA).

RESULTS

The principal findings indicated that T1 and T2 values exhibited a progressive increase with the severity of fibrosis, demonstrating a positive correlation with collagen deposition and inflammatory factors, especially the hydroxyproline content (r = 0.880, P < 0.001). The HYP content exhibited a progressive increase with advancing fibrosis stages (ρ = 0.914, P < 0.001). Similarly, T1 values increased significantly across fibrosis stage(ρ = 0.854, P < 0.001). Statistical comparison of these coefficients revealed no significant difference (Z = 1.031, P = 0.303). ROC curve analysis showed that T1 mapping was more accurate than T2 mapping in detecting collagen deposition and inflammation.

CONCLUSIONS

This study highlighted the potential of T1/T2 mapping as non-invasive and quantitative biomarkers for diagnosing and staging liver fibrosis, providing new insights into the onset and progression of liver fibrosis.

3D skin bioprinting as promising therapeutic strategy for radiation-associated skin injuries

Both cutaneous radiation injury and radiation combined injury (RCI) could have serious skin traumas, which are collectively referred to as radiation-associated skin injuries in this paper. These two types of skin injuries require special managements of wounds, and the therapeutic effects still need to be further improved. Cutaneous radiation injuries are common in both radiotherapy patients and victims of radioactive source accidents, which could lead to skin necrosis and ulcers in serious conditions. At present, there are still many challenges in management of cutaneous radiation injuries including early diagnosis, lesion assessment, and treatment prognosis. Radiation combined injuries are special and important issues in severe nuclear accidents, which often accompanied by serious skin traumas. Mass victims of RCI would be the focus of public health concern. Three-dimensional (3D) bioprinting, as a versatile and favourable technique, offers effective approaches to fabricate biomimetic architectures with bioactivity, which provides potentials for resolve the challenges in treating radiation-associated skin injuries. Combining with the cutting-edge advances in 3D skin bioprinting, the authors analyse the damage characteristics of skin wounds in both cutaneous radiation injury and RCI and look forward to the potential value of 3D skin bioprinting for the treatments of radiation-associated skin injuries.

Simultaneous estimation of the cellular water exchange rate, intracellular volume fraction, and longitudinal relaxation rate in cancer cells

The purpose of the current study was to investigate the feasibility of simultaneously estimating the cellular water efflux rate ( k ie ), intracellular longitudinal relaxation rate ( R 10 i ), and intracellular volume fraction ( v i ) of a cell suspension using multiple samples with different gadolinium concentrations. Numerical simulation studies were conducted to assess the uncertainty in the estimation of k ie , R 10 i , and v i from saturation recovery data using single (SC) or multiple concentrations (MC) of gadolinium-based contrast agent (GBCA). In vitro experiments with 4 T1 murine breast cancer and SCCVII squamous cell cancer models were conducted at 11 T to compare parameter estimation using the SC protocol with that using the MC protocol. The cell lines were challenged with a Na+ /K+ -ATPase inhibitor, digoxin, to assess the treatment response in terms of k ie , R 10 i , and v i . Data analysis was conducted using the two-compartment exchange model for parameter estimation. The simulation study data demonstrate that the MC method, compared with the SC method, reduces the uncertainty of the estimated k ie by decreasing the interquartile ranges from 27.3% ± 3.7% to 18.8% ± 5.1% and the median differences from ground truth from 15.0% ± 6.3% to 7.2% ± 4.2%, while estimating R 10 i and v i simultaneously. In the cell studies, the MC method demonstrated reduced uncertainty in overall parameter estimation compared with the SC approach. MC method-measured parameter changes in cells treated with digoxin increased R 10 i by 11.7% (p = 0.218) and k ie by 5.9% (p = 0.234) for 4 T1 cells, respectively, and decreased R 10 i by 28.8% (p = 0.226) and k ie by 1.6% (p = 0.751) for SCCVII cells, respectively. v i did not change noticeably by the treatment. The results of this study substantiate the feasibility of using saturation recovery data of multiple samples with different GBCA concentrations for simultaneous measurement of the cellular water efflux rate, intracellular volume fraction, and intracellular longitudinal relaxation rate in cancer cells.

Current insights of applying MRI in Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is an autoimmune disease related to Grave's disease (GD). The therapeutic strategies for GO patients are based on precise assessment of the activity and severity of the disease. However, the current assessment systems require development to accommodate updates in treatment protocols. As an important adjunct examination, magnetic resonance imaging (MRI) can help physicians evaluate GO more accurately. With the continuous updating of MRI technology and the deepening understanding of GO, the assessment of this disease by MRI has gone through a stage from qualitative to precise quantification, making it possible for clinicians to monitor the microstructural changes behind the eyeball and better integrate clinical manifestations with pathology. In this review, we use orbital structures as a classification to combine pathological changes with MRI features. We also review some MRI techniques applied to GO clinical practice, such as disease classification and regions of interest selection.