Sequential multi-parametric MRI in assessment of the histological subtype and features in the malignant pleural mesothelioma xenografts

Our plain-English summary of Sequential multi-parametric MRI in assessment of the histological subtype and features in the malignant pleural mesothelioma xenografts, by Z. Zhang, S. Shen, J. Ma, et al (Heliyon, 2023).

The study

• Authors: Z. Zhang, S. Shen, J. Ma, T. Qi, C. Gao, X. Hu, D. Han, Y. Huang
• Journal: Heliyon
• Published: 2023;9(4):e15237
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: It is still a challenge to find a noninvasive technique to distinguish the histological subtypes of malignant pleural mesothelioma (MPM) and characterize the development of related histological features. We investigated the potential value of multiparametric MRI in the assessment of the histological subtype and development of histologic features in the MPM xenograft model.

Methods: MPM xenograft models were developed by injecting tumour cells into the right axillary space of nude mice. The T1, T2, R2*, T2*, apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) at 14 d, 28 d, and 42 d were measured and compared between the epithelial and biphasic MPM. Correlations between multiparametric MRI parameters and histologic features, including necrotic fraction (NF) and microvessel density (MVD), were analysed.

Results: This study found that T2, T2* and IVIM-DWI parameters can reflect the spatial and temporal heterogeneity of MPM. Compared to the epithelial MPM, T2 and T2* were higher and ADC, D, D*, and f were lower in the biphasic MPM (P < 0.05). MRI parameters were different in different stages of epithelial and biphasic MPM. Moderate correlations were found between ADC and tumor volume and NF in the epithelial MPM, and there was a correlation between f and tumor volume and NF and MVD in the two groups.

Conclusion: MRI parameters changed with tumor progression in a xenograft model of MPM. MRI parameters may provide useful biomarkers for evaluating the histological subtype and histological features development of MPM.

© 2023 The Authors.

In plain English

This was an animal experiment testing whether MRI scans could tell apart two types of malignant pleural mesothelioma (MPM) tumors grown in mice. It did not study asbestos exposure. The authors injected human mesothelioma cells into the right armpit area of 42 female nude mice: 21 received an epithelioid cell line (NCI-H226) and 21 a biphasic cell line (MSTO-211H). Groups of seven mice were scanned at 14, 28 or 42 days. The tumors were then removed and examined for dead tissue (necrotic fraction) and small blood vessels (microvessel density). Compared with the epithelioid tumors, the biphasic tumors had higher T2 and T2* values and lower ADC, D, D* and f values (all p less than 0.05). T1 and R2* did not differ significantly. In the epithelioid group, ADC was moderately negatively correlated with tumor volume and necrotic fraction. In the biphasic group, f was negatively correlated with tumor volume, necrotic fraction and microvessel density. The authors concluded that MRI measures differed between the two subtypes. They noted limits: no sarcomatoid cell line was available, the sample was small, and the tumors were grown under the skin.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal experiment: human MPM cell lines grown as tumors (xenografts) under the skin of nude mice, scanned with several MRI techniques at three time points and then examined under the microscope
• Who was studied: 42 female BALB/c-nu/nu nude mice, 4 to 6 weeks old, split into an H226 group (n = 21) and an MSTO-211H group (n = 21), with 7 mice per group scanned at each of 14, 28 and 42 days. The work was done at the First Affiliated Hospital of Kunming Medical University, China.
• Exposure: No asbestos exposure was studied. Mice were injected with human epithelioid MPM cells (NCI-H226) or human biphasic MPM cells (MSTO-211H).
• Main results:
  • T2 and T2* were higher in the MSTO-211H (biphasic) group than in the H226 group: T2 92.73 vs 86.69 ms (p = 0.045) and T2* 15.10 vs 11.67 ms (p = 0.02), per Table 2.
  • ADC, D, D* and f were lower in the MSTO-211H group than in the H226 group (all p less than 0.05). For example, f was 19.44% vs 25.28% (p = 0.016), per Table 2.
  • T1 and R2* values did not differ significantly between the two groups.
  • In the H226 group, ADC and D decreased significantly at 28 and 42 days compared with 14 days.
  • Tumor volume, necrotic fraction and microvessel density were significantly smaller in the H226 group than in the MSTO-211H group, overall and at each time point.
  • In the H226 group, ADC was moderately negatively correlated with tumor volume (r = −0.53) and necrotic fraction (r = −0.508).
  • In the MSTO-211H group, f was negatively correlated with tumor volume (r = −0.560), necrotic fraction (r = −0.507 in Table 3) and microvessel density (r = −0.554).
• The authors' conclusion: The authors concluded that MRI functional measures differ between the two MPM subtypes, and that IVIM measures change as tumor volume increases and may help evaluate tumor development and prognosis.
• Limitations the authors state:
  • Tumors were not evaluated in 3D. MRI and tissue findings could not be matched to the same slice, and single sections may not represent the whole heterogeneous tumor.
  • No sarcomatoid cell line was available, so only epithelioid and biphasic cell lines were studied.
  • The animal sample size was limited.
  • Tumors were implanted under the skin of the armpit rather than in the chest cavity, which the authors note better simulates true MPM.

Topics

Medical terms in this study, explained in our Lexicon: Histological Subtype, Pleural Mesothelioma, Biphasic Mesothelioma, Biomarker.

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