Di Geng1, Xiance Zhao2, Yishi Wang3, Xiaoquan Xu1, and Feiyun Wu1
1Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China, Nanjing, China, 2Philips Healthcare, Shanghai, China, Shanghai, China, 3Philips Healthcare, Beijing, China, Beijing, China
Synopsis
Keywords: Head & Neck/ENT, Head & Neck/ENT
IMPULSED (Imaging Microstructural Parameters Using Limited Spectrally Edited Diffusion) imaging method based on time-dependent diffusion magnetic resonance imaging (MRI) could be used to quantify cell sizes. We found that several quantitative parameters derived from IMPULSED including Vin (intracellular volume fraction), d (volume-weighted mean cell size) and cellularity showed significant differences between polymorphic adenoma (PA) and Warthin’s tumor (WT) in the parotid gland. Our findings shed light on the role of IMPULSED-derived quantitative parameters in distinguishing PAs from WTs preoperatively.
Introduction
The size of the cell is an important feature of all tissues and varies greatly from different origin. Imaging Microstructural Parameters Using Limited Spectrally Edited Diffusion (IMPULSED) is a novel and advanced technology enabled quantifying cancer cell size and cellularity in common solid tumors1. Previous studies have proved that IMPULSED-derived parameters could be used to assess cell size variations in tumors, and predict the therapeutic effect in the patients with breast cancer2. In this study, we aimed to investigate the utility of quantitative parameters derived from IMPULSED in differentiating polymorphic adenoma (PA) from Warthin’s tumor (WT) in the parotid gland.Methods
Thirty consecutive patients with parotid gland tumors were enrolled, including 23 patients with PAs and 7 patients with WTs. All MRI examinations were performed using a 3T MR scanner (Ingenia CX, Philips Healthcare). The IMPULSED method integrated a set of pulse sequences including not only conventional pulsed gradient spin echo (PGSE) acquisitions, but also oscillating gradients in spin echo (OGSE) sequences acquisitions with two frequencies (N = 1 and 2), from which cell size in vivo was embodied more sensitively by using different effective diffusion time. DWI data were processed with an in-house developed software (MRI_Cytometry) and four IMPULSED-derived parameters including Vin (intracellular volume fraction), d (volume-weighted mean cell size), Dex (extracellular diffusion coefficient) and cellularity were obtained. MannWhitney U test and Student’s T-test were performed for statistical analysis.Results
WTs showed significantly higer Vin and cellularity than PAs [0.35 ± 0.07 vs 0.20 ± 0.09, p < 0.001; 3.88 (2.79 - 4.77) vs 1.64 (1.10 - 2.21), p = 0.001]. The d of WTs was significantly lower than that of PAs (12.59 ± 1.25 vs 14.46 ± 1.17, p = 0.001). However, no significant difference of Dex was found between two groups (p = 0.081).Discussion
In this study, we implemented IMPULSED, a noninvasive imaging technology, to distinguish PAs and WTs by quantifying cell size of tumors in clinical MRI scanner. Histologically, PAs were featured with epithelial cells and fibromyxoid stroma and have capsules3, while WTs were featured with an oncocytic epithelial cell component arranged in double layer and a lymphoid tissue stroma4. The pathological differences may contributed to cell size variations among two parotid gland tumors. Although PAs and WTs are both benign tumors, their biological behaviors are quite different. PAs have higher malignant tendency and recurrence rate compared with WTs5. Using IMPULSED-derived quantitative parameters based on time-dependent diffusion MRI for accurate preoperative evaluation can protect the patients from invasive biopsy.Conclusion
The quantitative parameters derived from IMPULSED method have the potential to assess cell size in parotid gland tumors, which could help differentiate parotid polymorphic adenoma from Warthin’s tumor. Acknowledgements
No acknowledgement found.References
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