胸部低剂量CT在新型冠状病毒疾病患者出院后复查的应用价值

目的 探讨胸部低剂量CT在新型冠状病毒疾病（COVID-19）患者好转出院后复查应用价值。方法 回顾性分析2020年3月17日至3月25日经武汉大学人民医院治疗出院后的58例COVID-19患者胸部低剂量CT表现，由两名影像医师独立评价CT图像质量，采用5分法进行评分。并计算信噪比（SNR）、背景噪声（SD_air）及辐射剂量。结果 出院前常规剂量组和出院后复查低剂量组图像主观评分观察者1和观察者2分别为4.45±0.22、3.88±0.33（P>0.05）和4.37±0.18、3.91±0.35（P>0.05）；低剂量组的SNR与SD_air分别为4.39±0.95和7.19±2.41，显著低于常规组的5.14±1.06（Z=-5.551，P<0.001）和6.48±1.57（Z=-3.217，P<0.001），图像质量均能满足临床诊断。低剂量组的CT容积剂量指数（CTDI_vol）、剂量长度乘积（DLP）及有效剂量（E）分别为（2.41±0.09） mGy、（88.03±5.33） mGy·cm和（1.23±0.17） mSv，均显著低于常规组［（10.53±1.03） mGy，（338.74±34.64） mGy·cm，（4.74±0.48） mSv，Z=-6.568、-6.624、-5.976，P<0.001）。结论 COVID-19患者出院后可采用胸部低剂量CT复查。

Application value of post-discharge chest low-dose CT for patients with COVID-19

Objective To explore the value of chest low-dose CT (LDCT) in post-discharge follow-up assessments of patients with coronavirus disease 2019 (COVID-19 ). Methods The chest CT findings of 58 patients with COVID-19 from March 17 to March 25, 2020 at Remin Hospital of Wuhan University were retrospectively analyzed. Two radiologists independently scored the subjective image quality on a 5-point Likert scale. The signal-to-noise ratio (SNR) and SD_air of images and the CT radiation dose parameters were calculated, including the CT volume dose index (CTDI_vol), dose length product (DLP), and effective radiation dose (E ). Results The subjective image quality scores on CT images obtained before and after discharge by readers 1 and 2, were 4.45±0.22, 3.88±0.33 (P>0.05) and 4.37±0.18, 3.91±0.35 (P>0.05 ), respectively. The SNR and SD_air in LDCT after discharge were 4.39±0.95 and 7.19±2.41, which were significantly lower than those in routine chest CT before discharge (5.14±1.06, Z=-5.551, P<0.001; 6.48±1.57, Z=-3.217, P<0.001 ). All of the obtained images were sufficient for diagnosis. The CTDI_vol, DLP, and E in LDCT were significantly lower than those in routine CT (2.41±0.09), (10.53±1.03)mGy, Z=-6.568, P<0.001; (88.03±5.33), (338.74±34.64)mGy·cm, Z=-6.624, P<0.001; and (1.23±0.17), (4.74±0.48)mSv, Z=-5.976, P<0.001 ]. Conclusions Patients with COVID-19 can be followed up with low-dose chest CT after discharge.