^(18)F-FDG PET/MR与PET/CT在乳腺肿瘤诊断中的初步对比研究

Preliminary Comparative study of PET/MR and PET/CT in the Diagnosis of Breast Tumors

目的分析一体化PET/MR乳腺显像对乳腺病灶的诊断价值,并与PET/CT比较。方法回顾性分析59例怀疑乳腺肿瘤的女性患者同日先后行全身^(18)F-FDG PET/CT显像及采用乳腺专用线圈的^(18)F-FDG PET/MR局部显像的相关资料。以病理结果为金标准。用χ~2检验比较两者检出率的差异;用Pearson相关性分析、Bland-Altman分析及t检验对两者最大标准摄取值(SUVmax)及靶区/本底比值(T/B)进行比较分析;运用χ~2检验比较各指标诊断效能的差异。结果共94个乳腺病灶获得病理结果,其中乳腺癌病灶57个,乳腺淋巴瘤病灶2个,横纹肌肉瘤病灶3个,良性结节32个。PET/MR总体比PET/CT多发现24个病灶,两者有显著统计学差异(χ~2=25.71,P<0.01)。有46个病灶同时在两台PET上呈阳性,另有8个病灶PET_(-MR)呈阳性,而PET_(-CT)呈阴性,其中恶性7个。PET阳性病灶的SUV_(max-MR)与SUV_(max-CT)有良好的一致性(r=0.989)。PET_(-MR)图像的T/B_(-MR)值较PET_(-CT)图像的T/B_(-CT)高,均值差为2.3(95%CI:-3.5～8.0),有显著统计学差异(t=2.72,P<0.01)。PET/MR的灵敏度、特异度及准确率为95.2%(59/62)、90.6%(29/32)、93.6%(88/94),PET/CT的灵敏度、特异度及准确率为75.8%(47/62)、93.8%(30/32)、81.9%(77/94),二者灵敏度与准确率有统计学差异(χ~2=9.63,P<0.01;χ~2=5.99,P<0.05)。≥10 mm恶性病灶的PET阳性率92.5%(37/40),明显高于<10 mm恶性病灶的PET阳性率63.6%(14/22)(χ~2=8.10,P<0.01)。对于≥10 mm的病灶,两者的灵敏度、特异度及准确率均无统计学差异(χ~2=1.05、0.38、0.15,P>0.05)。对于41个<10 mm的病灶,PET/MR的灵敏度90.9%(20/22)和准确率92.7%(38/41),高于PET/CT的灵敏度和准确率45.5%(10/22)、68.3%(28/41)(χ~2=10.48、7.77,P<0.01)。结论 PET/MR对于乳腺肿瘤的诊断具有较高的价值。与PET/CT相比,PET/MR的PET图像信噪比更高、分辨率更好,MR提供的诊断信息更多,尤其是对于<10 mm的病灶,其诊断价值更高。

Objective This study aims to evaluate the diagnostic value of breast imaging in a hybrid TOF(Time of Flight,TOF) PET/MR system with a dedicated breast coil,and to compare the difference from PET/CT. Methods Fifty-nine patients suspected of breast tumor,were performed whole body PET/CT examination and PET/MR localized examination with a 16 channel coil on the same day. By using the pathological results as the gold standard, the χ2 test was conducted to compare the diagnostic efficacy between PET/CT and PET/MR. Results A total of 94 breast lesions were identified,which consisted of 57 breast cancers,2 breast lymphomas,3 rhabdomyosarcomas,and 32 benign lesions. 24 additional lesions were found in PET/MR compared with PET/CT,and significant statistical difference was found between their detection rates, SUVmax and T/B(Tumor/Background,T/B) ratios of PET images. The sensitivity,specificity and accuracy rates were respectively 95.2%, 90.6%,93.6% for PET/MR and 75.8%,93.8%,81.9% for PET/CT,while their sensitivities and accuracy were statistically different(χ2=9.63,P<0.01;χ2=5.99,P<0.05). The positive rate of PET for malignant lesions equal to or greater than 10 mm was significantly higher than that for sub-centimeter malignant lesions(χ2=8.10,P<0.01). For the 41 lesions in the sub-centimeter category,the sensitivity and accuracy(90.9%,92.7%) of PET/MR was significantly higher than those of PET/CT(45.5%,68.3%),(χ2=8.00,4.57,P<0.05). Conclusion Hybrid PET/MR imaging provides valuable diagnosis for localized breast lesions. Compared with PET/CT,there was better imaging signal-to-noise ratio(SNR) and contrast. The diagnostic efficacy is much better, particularly for the lesions in the sub-centimeter category.