Prospective study of susceptibility weighted imaging on MR for distinguishing malignant from benign parotid lesions / 中华放射学杂志

ABSTRACT

Objective To explore the diagnostic performance of susceptibility weighted imaging (SWI) in distinguishing malignant from benign parotid lesions.Methods We prospectively evaluated preoperative SWI findings of 41 patients with 12 malignant and 29 benign parotid lesions by surgical pathology, and explore the intravenous distribution, the largest diameter of veins (dv-max), the number of veins per unit area (N/Svein) and the graduation of intratumoral susceptibility signal intensity (ITSS).The parameters was analyzed by Chi-square test, Independent t-test, Mann-Whitney U rank test and receiver operating characteristics (ROC) curves with SPSS 16.0 software.Results (1) For intravenous distribution, the benign ones mainly distributed around peripheral areas, accounting for 89.7％ (26/29), while the malignant ones were centrally distributed, making up 10/12.There were significant difference (x2=20.882, P=0.000) between benign and malignant ones.(2) The largest diameter of veins (dv-max) of benign and malignant lesions were (1.1±0.5) mm and (2.5 ± 1.0)mm respectively.There were significant difference (t=4.633, P=0.000) between benign and malignant ones.(3) The N/Svein of benign lesions were (0.80±0.92) per cm2, while that of malignant ones are (1.07±0.69) per cm2.The N/Svein (t=0.9143, P=0.367) was statistically insignificant.(4) For the graduation of ITSS,among benign lesions, there were 3 cases of grade 0, 22 cases of grade 1, 2 cases of grade 2 and 2 cases of grade 3.Meanwhile, there were 2 cases of grade 1, 5 cases of grade 2 and 5 cases of grade 3 among malignant lesions.When the Youden index reached the highest point, the optimal diagnostic threshold of dv-max and ITSS values were 1.75 mm and 1.5 mm, the corresponding area under the ROC curve (AUC) were 0.924 and 0.856 respectively.The sensitivity of d and ITSS ondiagnosis were 10/12 and 10/12, and the specificity of that were 96.6％ and 86.2％ respectively.The table shows that the sensitivity and specificity of intravenous distribution in diagnosis of malignant lesions are 10/12 and 89.7％.Conclusions The results provided evidence that SWI may be helpful in distinguishing malignant from benign parotid lesions, and it is worth to be generalized in clinical medicine.