3341. Role of Contrast-Enhanced Susceptibility-Weighted Imaging (CE-SWI) for the Assessment of Response and Progression in Desmoid Fibromatosis
Authors * Denotes Presenting Author
  1. Raul Valenzuela *; The University of Texas MD Anderson Cancer Center
  2. Elvis Duran Sierra; The University of Texas MD Anderson Cancer Center
  3. Mathew A. Canjirathinkal; The University of Texas MD Anderson Cancer Center
  4. Colleen M. Costelloe; The University of Texas MD Anderson Cancer Center
  5. John E. Madewell; The University of Texas MD Anderson Cancer Center
  6. William A. Murphy Jr.; The University of Texas MD Anderson Cancer Center
  7. Behrang Amini; The University of Texas MD Anderson Cancer Center
Subjective clinical imaging evaluations often consider progressive desmoid tumors to have a higher proportion of T2 hyperintense and T1 shortened enhancing components, whereas responding or mature more collagenized tumors demonstrate a higher proportion of T2 hypointense nonenhancing parts. This study aimed to determine the utility of the novel use of contrast-enhanced susceptibility-weighted imaging (CE-SWI) as a single sequence capable of simultaneously separating the T1 shortening enhancing, T2 hyperintense immature, and the T2 hypointense collagenized mature components, using volumetric measurements and first-order radiomic features.

Materials and Methods:
This pilot study included 10 single-lesion extremity desmoid fibromatosis patients undergoing standard-of-care MRI examinations, including CE-SWI, performed between March 2021 and May 2023. Three-dimensional manual tumor segmentation was performed using the MIM commercial software in 48 volumes of interest. Maximum diameter, volume, and modified Choi (mChoi) measurements were computed from CE-SWI and T2-STIR sequences. In addition, five first-order radiomic features, including mean, skewness, kurtosis, and 10th and 90th percentiles, were computed using in-house developed software CARPI-AF (Cancer Radiomic and Perfusion Imaging Automated Framework).

Two patients displayed progression by the T2-based RECIST reference standard. In the same group, concordant progression was detected by CE-SWI volume and mChoi at an average of 4.5 months earlier than T2-based RECIST. Eight patients were classified as stable disease by T2-based RECIST. No cases of concordant stability were observed by T2 or CE-SWI-based volume or Choi. From the T2-based stable RECIST group, discrepant progression was determined in four patients by an increase of greater than 25% of T2-based volume (in three patients) and CE-SWI-based volume (in two patients). From the T2-based stable RECIST group, a discrepant positive response was determined in four patients predicted by CE-SWI mChoi (in three patients) and T2 mChoi (in four patients).

This study suggests that trained cancer radiologists tend to be relatively insensitive to early volumetric progression and sensitive to signal-based (mChoi) response assessment. The novel use of CE-SWI-based volumetric and mChoi measurements could improve the prediction of response/progression in desmoid tumors by providing a better evaluation using tri-dimensional tumor size assessment and increased discrimination between the collagenized mature component and the enhancing immature components, respectively, with predominant T2 hypointense collagenized mature-responding and T2 hyperintense immature-progressive disease. CE-SWI tends to outperform T2, demonstrating a higher proportion of 90th-percentile voxels, which are typically dominant in immature tumor components.