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The Desmoid Tumor Research Foundation

June 2024

MRI T2 mapping assessment of T2 relaxation time in desmoid tumors as a quantitative imaging biomarker of tumor response: preliminary results

Author Information

Felipe F Souza 1 2, Gina D'Amato 2 3, Emily Elizabeth Jonczak 2 3, Philippos Costa 4, Jonathan C Trent 2 3, Andrew E Rosenberg 2 5, Raphael Yechieli 2 6, H Thomas Temple 2 7, Pradip Pattany 1, Ty K Subhawong 1 2

1Department of Radiology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States.2Sylvester Comprehensive Cancer Center, University of Miami Health System, Miami, FL, United States.3Department of Internal Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States.4Department of Internal Medicine, Yale Medicine, New Haven, CT, United States.5Department of Pathology & Laboratory Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States.6Department of Radiation Oncology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States.7Department of Orthopaedics, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, United States.

Publication

Front Oncol

Summary

Objectives: Because size-based imaging criteria poorly capture biologic response in desmoid-type fibromatosis (DF), changes in MRI T2 signal intensity are frequently used as a response surrogate, but remain qualitative. We hypothesized that absolute quantification of DF T2 relaxation time derived from parametric T2 maps would be a feasible and effective imaging biomarker of disease activity. Methods: This IRB-approved retrospective study included 11 patients with DF, managed by observation or systemic therapy, assessed by 3T MRI. Tumor maximum diameter, volume, and T2-weighted signal intensity were derived from manual tumor segmentations. Tumor:muscle T2 signal ratios were recorded. Two readers measured tumor T2 relaxation times using a commercial T2 scanning sequence, manual ROI delineation and commercial calculation software enabling estimation of reader reliability. Objective response rates based on RECIST1.1 and best responses were compared between size-based and signal-based parameters. Results: Median patient age was 52.6 years; 8 subjects were female (73%). Nine patients with longitudinal assessments were followed for an average of 314 days. Median baseline tumor diameter was 7.2 cm (range 4.4 - 18.2 cm). Median baseline T2 was 65.1 ms (range 40.4 - 94.8 ms, n=11); median at last follow-up was 44.3 ms (-32% from baseline; range 29.3 - 94.7 ms, n=9). T2 relaxation times correlated with tumor:muscle T2 signal ratios, Spearman p=0.78 (p<0.001). T2 mapping showed high inter-reader reliability, ICC=0.84. The best response as a percentage change in T2 values was statistically significant (mean -17.9%, p=0.05, paired t-test) while change in diameter was not (mean -8.9%, p=0.12). Conclusions: Analysis of T2 relaxation time maps of DF may offer a feasible quantitative biomarker for assessing the extent of response to treatment. This approach may have high inter-reader reliability.

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