Objective: To quantitatively evaluate the early radiation injury of salivary glands in patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT). Methods: Twenty patients with NPC between 2014 and 2015 from the Second Affiliated Hospital of Soochow University were retrospectively analyzed.All patients underwent an MRI scan before and after IMRT.The volumes, T(1)WI, T(2)WI signal intensity(SIs) and apparent diffusion coefficient (ADCs) of the parotid and submandibular glands were measured.The relative signal intensity (RSIs) of each salivary gland was calculated with cerebrospinal fluid as control.The quantitative parameters of salivary glands were compared before and after radiotherapy. Results: The volumes (cm(3)) and T(1)WI RSIs of the parotid and submandibular glands (14.88±6.00, 5.21±1.76, 2.98±1.05, 1.88±0.42, respectively) were significantly lower than those before radiotherapy (22.26±8.26, 7.76±2.45, 3.58±1.02, 2.27±0.50, respectively) (t=9.921, 4.013, 10.126, 4.202, respectively, P=0.000 for all). The T(2)WI RSIs and ADCs (×10(-3) mm(2)/s) of the parotid and submandibular glands (0.50 ± 0.08, 0.41±0.04, 1.31±0.19, 1.50±0.13, respectively) were significantly higher than those before radiotherapy (0.45±0.07, 0.33±0.05, 1.02±0.21, 1.23±0.13, respectively) (t=-4.846, -9.276, -9.957, -10.679, respectively, P=0.000 for all). The volumes of parotid and submandibular glands were correlated with ADCs (r=-0.512, P=0.000; r=-0.358, P=0.001; respectively). The volumes and ADCs of submandibular glands were correlated with T(1)WI RSIs and T(2)WI RSIs(P<0.05). Conclusion: MRI can quantitatively evaluate the early changes of salivary glands after radiotherapy of nasopharyngeal carcinoma as a noninvasive method, and has high clinical application potential.
目的：探讨应用磁共振(MR)定量评价调强放疗(IMRT)后鼻咽癌患者涎腺的早期放射性损伤的价值。 方法：对在2014至2015年间苏州大学附属第二医院就诊的20例鼻咽癌患者在放疗前及放疗后1个月行MR检查，测量腮腺及颌下腺的体积、T(1)WI、T(2)WI信号强度与表观扩散系数(ADC)值。以脑脊液为对照，计算各涎腺的相对信号强度(RSI)。比较放疗前后涎腺各定量参数的差异。 结果：放疗后早期腮腺和颌下腺体积与T(1)WI RSI值分别为(14.88±6.00)、(5.21±1.76) cm(3)，2.98±1.05、1.88±0.42显著低于放疗前(22.26±8.26)、(7.76±2.45) cm(3)，3.58±1.02、2.27±0.50(t值分别为9.921、4.013、10.126、4.202，P值均为0.000)；放疗后腮腺和颌下腺T(2)WI RSI值与ADC值分别为0.50±0.08、0.41±0.04，(1.31±0.19)、(1.50±0.13) ×10(-3) mm(2)/s，显著高于放疗前0.45±0.07、0.33±0.05，(1.02±0.21)、(1.23±0.13)×10(-3) mm(2)/s(t值分别为-4.846、-9.276、-9.957、-10.679，P值均为0.000)。腮腺和颌下腺的体积与ADC值有相关性(r＝-0.512，P＝0.000；r＝-0.358，P＝0.001)。颌下腺体积和ADC值与T(1)WI 、T(2)WI RSI值均有相关性(P<0.05)。 结论： MRI可以无创地定量评价鼻咽癌IMRT放疗后涎腺的早期变化，具有较高的临床应用潜能。.
Keywords: Magnetic resonance imaging; Radiotherapy, computer-assisted; Salivary glands; Xerostomia.