CT MRI和PET-CT对鼻咽癌局部肿瘤检测差异的初步研究

目的：比较CT、MRI和18F-PET-CT对鼻咽癌局部肿瘤的检测差异和探讨18F-PET-CT检测鼻咽癌局部肿瘤的应用价值。方法：2003年12月至2005年8月,中山大学肿瘤防治中心连续收治的原发鼻咽癌患者53例进入研究。所有患者在治疗前10天内以同一固定体位,完成增强CT、MRI和PET-CT扫描检查,在CT、MRI和PET-CT上分别读片判定鼻咽癌局部侵犯范围。结果：CT、MRI与PET-CT分别检出咽后淋巴结转移31例（58.5%）、36例（67.9%）、20例（37.7%）,CT、MRI检出率显著高于PET-CT（P=0.02,P=0.001）;CT稍低于MRI,但两者间无显著性差异（P=0.314）。CT和MRI检出的最大横径〈1cm的咽后淋巴结转移,PET-CT大部分未能显示;最大横径≤0.5cm或并发液化坏死明显的咽后淋巴结转移,PET-CT均未能检出。对鼻腔、口咽、咽旁间隙、颈动脉鞘区、颞下窝、翼腭窝和颅底骨质侵犯的检出,CT、MRI和PET-CT无明显差异;对海绵窦和鼻窦侵犯的检出,MRI可能优于CT和PET-CT。结论：对鼻咽癌局部肿瘤侵犯的检测,PET-CT较CT和MRI无明显优势;对最大横径〈1cm的咽后淋巴结转移,PET-CT的检出率明显低于CT或MRI;对最大横径≤0.5cm或并发液化坏死的咽后淋巴结转移的检测,PET-CT可能存在较大局限。

Preliminary Studies of Differences in Local Detection of Nasopharyngeal Carcinoma using CT, MRI and PET-CT

Objectives: To compare the differences in diagnosis of regional nasopharyngeal carcinoma among CT, MRI and PET-CT and to explore the value of using 18F-PET-CT detection for nasopharyngeal carcinoma (NPC). Methods: Between December 2003 and August 2005, 53 patients with NPC who were treated in our hospital were enrolled in the study. Before treatment, contrast-enhanced CT, MRI and 18FDG-PET-CT scanning were performed. Film reading of CT, MRI and PET-CT was conducted to determine the extent of regional invasion of NPC. Results: Among 53 patients, positive detection rates of retropharyngeal lymphatic metastases were 58.5% (31/53), 67.9% (36/53) and 37.7 % (20/53) based on CT, MRI and PET-CT, respectively. The detection rates of CT and MRI scans were markedly higher compared to that of PET-CT (P=0.02,P=0.001) but there was no significant difference in the positive rate of detection between CT and MRI (P=0.314). The retropharyngeal lymphatic metastasis (RLM) with a maximum transverse diameter of less than 1 cm could be found by CT and MRI, but not PET-CT. Neither the RLM with a maximum transverse diameter of less than or equal to 0.5 cm nor that with an overt liquefied necrosis could be found by PET-CT scanning. There was no obvious difference among CT, MRI and PET-CT in the ability to detect invasion into other tissues, such as the nasal cavity, oral pharynx, parapharyngeal space, carotid sheath area, infratemporal fossa, sphenomaxillary fossa and sclerotic invasion of the basion. For detection of cavernous sinus and nasal sinuses, MRI may be superior to CT and PET-CT. Conclusions: PET-CT is inferior for detecting local encroachment of NPC, compared to CT and MRI. For the detection of RLM with a maximum transverse diameter of less than 1 cm, the detection rate of PET-CT is obviously lower compared to CT and MRI. For the detection of RLM with a maximum transverse diameter of less than or equal to 0.5 cm or with concurrent liquefied necrosis, PET-CT has even more limitations and shortcomings.