E1113. Diagnostic Accuracy of CT and MR Features For Detecting Atypical Lipomatous Tumors and Malignant Liposarcomas
  1. Mitchell Wilson; University of Alberta
  2. Jordan Haidey; University of Alberta
  3. Mohammad Murad; Mayo Clinic - Rochester
  4. Logan Sept; University of Alberta
  5. Gavin Low; University of Alberta
Differentiating benign from locally aggressive and malignant adipocytic tumors is of critical importance for management, though core needle biopsy is known to have reduced accuracy for intermediate lesions. This results in an increased reliance on presurgical CT and/or MRI for differentiating benign from intermediate and malignant adipocytic lesions, although the accuracy of these modalities has not been well-defined in a systematic fashion. Consequently, this systematic review and meta-analysis compared the diagnostic accuracy of CT and MRI for differentiating atypical lipomatous tumors (ALT) and malignant liposarcomas (LPS) from benign lipomatous lesions.

Materials and Methods:
MEDLINE, EMBASE, Scopus, the Cochrane Library, and the gray literature from inception to January 2022 were systematically evaluated. Original articles with >5 patients evaluating the diagnostic accuracy of CT and/or MRI for detecting liposarcomas with a histopathological reference standard were included in analysis. Study, patient, imaging, and accuracy characteristics were acquired. Meta-analysis was performed using a bivariate mixed- effects regression model where possible, and fixed-effects method when less than 4 studies were available for an individual threshold. Risk of bias was evaluated using QUADAS-2.

Twenty-six studies with a total of 2613 patients were included in review. Mean/median reported patient ages ranged between 50 - 63 years. The summary sensitivity and specificity of radiologist gestalt for detecting liposarcomas was 85% (79 - 90% 95% CI) and 63% (52 - 72%), respectively. Deep depth to fascia, thickened septations, enhancing components and lesion size (>/= 10 cm) all demonstrated sensitivities >/= 85%. Other imaging characteristics including heterogenous/amorphous signal intensity, irregular tumor margin, and nodules present demonstrated lower sensitivities ranging from 43 - 65%. Inter-reader reliability for radiologist gestalt within studies ranged from fair to substantial (k=0.23 -0.7). Risk of bias was predominantly mixed for patient selection, low for index test and reference standard, and unclear for flow and timing.

Higher sensitivities for detecting ALT and LPS were achieved with radiologist gestalt, deep depth to fascia, thickened septations, enhancing components and large size. Combined clinical and imaging scoring and/or radiomics both show promise for optimal performance, though require further analysis with prospective study designs.