The Role of Quantitative Dynamic Contrast-enhanced-Magnetic Resonance Imaging and Diffusion-weighted Imaging in Differentiating the Grade of Soft Tissue Sarcomas

Purpose or Learning Objective: The grade is crucial in the prognosis, evaluation of metastatic risk, and management of soft tissue sarcomas (STS). Our study evaluated the role of quantitative dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI) parameters and diffusion-weighted imaging (DWI) in differentiating the grade of STS.

Methods or Background: From March 2022 to February 2023, histopathologic-diagnosed patients with STS in our center who underwent a DCE-MRI or DWI were selected, respectively. Patients with a history of chemotherapy or radiotherapy before MRI and patients with a diagnosis of liposarcoma were excluded. All the examinations were evaluated by two radiologists with specific experience in musculoskeletal imaging (3 and 4 years, respectively).

Patients’ age, sex, and the longest diameter of the mass (LD) were noted. DCE-MRI measurements were calculated from the volume transfer constant (K^trans) maps, avoiding bleeding, necrosis, and cystic areas. One region of interest (ROI) located the area with the highest perfusion (max), and the second ROI was located more widely in the same section (mean). Permeability parameters of the masses (K^trans, area under the curve [AUC], rate constant [K^ep], extravascular space [V_e]), and contrast enhancement curve types were noted (Figs. 1, 2, and 3). Using apparent diffusion coefficient (ADC) maps, minimum (min) and average ADC (mean) values were recorded (Figs. 1, 2, and 3).

STSs were divided into three groups according to their pathologic grades. Grades 1 and 2 were also combined, and STS were grouped into low and high grades. Parameters were analyzed separately between groups.

Results or Findings: A total of 14 patients, 3 women and 11 men, participated in our study. Four patients were diagnosed as STS grade 1; 2, grade 2; and 8, grade 3. The mean age of the patients was 58.07 years (± 16.35), and the mean LD was 113.36 mm (± 36.87). Interobserver agreement was excellent for maximum perfusion parameters and ADCmin and good for mean perfusion parameters and ADCmean. No significant difference was found between the groups regarding age and LD. There was a difference between ADCmean (P = 0.026), ADCmin (P = 0.029), and AUCmax (P = 0.047) when STS grade 1 versus grades 2 to 3 was compared. When the groups were compared as low and high grade, a significant difference was found in ADCmean (P = 0.027), ADC min (P = 0.030), K^transmax (P = 0.02), AUCmax (P = 0.014), and K^transmean (p = 0.039) values. No significant difference was observed in the evaluation with other parameters.

Conclusion: Although studies in the literature claim that ADC and positron emission tomography-computed tomography imaging can contribute to grade prediction, no study uses DCE-MRI parameters. We showed that ADCmin, ADCmean, AUCmax, K^transmax, and K^transmean values could help predict grades. To determine cut-off values, studies with larger patient groups are warranted.

Publication History

Article published online:
26 May 2023