低剂量与标准剂量CT对慢性鼻窦炎手术高风险患者图像质量和辐射剂量的影响

Evaluation of low-dose versus standard-dose CT examination in surgical high-risk patients with chronic rhinosinusitis

目的:比较低剂量和标准剂量多排螺旋CT对高风险慢性鼻窦炎患者(如合并哮喘、鼻窦手术史、鼻息肉、嗅觉缺失)手术鼻窦解剖结构的识别并探讨其与内镜鼻窦手术围术期并发症的相关性。方法:205名成年慢性鼻窦炎患者随机分为标准剂量组(n=85)和低剂量组(n=120),对鼻窦重要解剖结构(筛动脉前支、视神经、筛状板、筛骨眶板)的扫描图像质量评分。根据Lildholdt评分对鼻息肉进行评分,Sniffin'Sticks法评估嗅觉功能。结果:标准剂量CT扫描有效放射剂量平均值为0.785 m Sv,是低剂量CT扫描的10倍(0.078 m Sv,P<0.001)。每个亚组筛骨眶板的低剂量扫描图像质量均较标准剂量扫描明显更差;鼻息肉增大和嗅觉缺失亚组中,筛状板的低剂量扫描图像质量均比标准剂量扫描差(P<0.05)。所有结构低剂量扫描时最难识别的为筛状板。低剂量扫描和标准剂量扫描对于筛动脉前支识别的差异无统计学意义;筛动脉前支的图像质量处于平均水平,为次难识别的解剖结构。结论:对于合并支气管哮喘、鼻息肉增大(LS>2)、有鼻窦手术史和嗅觉缺失的慢性鼻窦炎患者,术前低剂量CT检查在识别外科手术解剖结构上可能不太有效。在无高风险因素的患者中,低剂量CT检查对鼻窦标志性结构具有与标准剂量CT检查相似的识别能力。在制定手术计划时,应充分评估患者的不同情况选择合适的检查方法以使合并症的风险减至最小。

Objective To compare identification of the surgically relevant anatomical structures via low- and standard-dose multi-slice spiral CT examination in patients with high-risk chronic rhinosinusitis （CRS） （i.e. presence of bronchial asthma, history of sinus surgery, advanced nasal polyposis and anosmia）, and to discuss its relevance with perioperative period of endoscopic sinus surgery. Methods A total of 205 adult CRS patients were randomly divided into standard-dose group （n=85） and low-dose CT group （n=120）. The scanning images of the vital anatomical structures （anterior ethmoid artery, optic nerve, cribriform plate and lamina papyracea） were scored. Polyp sizes were quantified according to the Lildholdt’s scale and Sniffin’ Sticks test was used to evaluate olfactory function. Results The mean value of the effective radiation dose in standard-dose group was 10 times higher than that in low-dose group （0.785 mSv vs 0.078 mSv; P〈0.001）. Identification of lamina papyracea on low-dose scans was significantly worse in each subgroup as comparison with standard-dose group, and the same was the case with cribriform plates in patients with advanced polyposis and anosmia （P〈0.05）. Cribriform plates were the most poorly identified among all the structures on low-dose images. Identification of anterior ethmoid artery didn’t show any statistical differences between low-dose group and standard-dose group. The anterior ethmoid artery was scored as an average-defined structure and was the second indiscernible. Conclusion Low-dose CT examination before operation may not sufficiently identify the surgically relevant anatomical structures in CRS patients accompanied with bronchial asthma, advanced nasal polyps （Lildholdt’s scale〉2）, history of sinus surgery and anosmia. But for the patient without any high-risk factors, low-dose CT examination shows a comparable identification of sinonasal landmarks with standard-dose CT examination. The conditions of different patients should be comprehensively evaluated in surgical planning for minimizing the risk of complications.