Tian Jiahe, Fu Liping, Yin Dayi, Zhang Jinming, Chen Yingmao, An Ningyu, Xu Baixuan
Department of Nuclear Medicine, General Hospital of the Chinese People's Liberation Army, Beijing, China.
Department of Radiology, Xiyuan, General Hospital of the Chinese People's Liberation Army, Beijing, China.
PLoS One. 2014 Mar 6;9(6):e90844. doi: 10.1371/journal.pone.0090844. eCollection 2014.
We compared PET/MRI with PET/CT in terms of lesion detection and quantitative measurement to verify the feasibility of the novel integrated imaging modality for oncological applications.
METHODOLOGY/PRINCIPAL FINDINGS: In total, 285 patients referred to our PET/CT center for oncological indications voluntarily participated in this same-day PET/CT and PET/MRI comparative study. PET/CT images were acquired and reconstructed following routine protocols, and then PET/MRI was performed at a mean time interval of 28±11 min (range 15-45 min). PET/MRI covered the body trunk with a sequence combination of transverse T1WI 3D-volumetric interpolated breath-hold, T2WI turbo spin echo with fat saturation, diffusion-weighted imaging with double b values (50 and 800 s/mm2), and simultaneous PET acquisition over 45 min/5 bed positions. The maximum standardized uptake value (SUVmax) was assessed by manually drawn regions of interest over fluorodeoxyglucose-positive lesions. Among 285 cases, 57 showed no abnormalities, and 368 lesions (278 malignant, 68 benign and 22 undetermined) were detected in 228 patients. When stand-alone modalities were evaluated, PET revealed 31 and 12 lesions missed by CT and MRI, respectively, and CT and MRI revealed 38 and 61 more lesions, respectively, than PET. Compared to CT, MRI detected 40 more lesions and missed 8. In the integrated mode, PET/CT correctly detected 6 lesions misdiagnosed by PET/MRI, but was false-negative in 30 cases that were detected by PET/MRI. The overall diagnosis did not differ between integrated PET/MRI and PET/CT. SUVmax for lesions were slightly higher from PET/MRI than PET/CT but correlated well (ρ = 0.85-0.91).
CONCLUSIONS/SIGNIFICANCE: The novel integrated PET/MRI performed comparatively to PET/CT in lesion detection and quantitative measurements. PET from either scanner modality offered almost the same information despite differences in hardware. Further study is needed to explore features of integrated PET/MRI not addressed in this study.
我们比较了PET/MRI与PET/CT在病变检测和定量测量方面的表现，以验证这种新型集成成像模式在肿瘤学应用中的可行性。
方法/主要发现：共有285名因肿瘤指征转诊至我们PET/CT中心的患者自愿参与了这项当日PET/CT与PET/MRI对比研究。PET/CT图像按照常规方案采集并重建，然后在平均时间间隔28±11分钟（范围15 - 45分钟）后进行PET/MRI检查。PET/MRI采用横向T1WI 3D容积内插屏气、脂肪饱和的T2WI快速自旋回波、双b值（50和800 s/mm²）的扩散加权成像以及45分钟/5个床位位置的同步PET采集的序列组合覆盖身体躯干。通过在氟脱氧葡萄糖阳性病变上手动绘制感兴趣区域来评估最大标准化摄取值（SUVmax）。在285例病例中，57例未显示异常，在228例患者中检测到368个病变（278个恶性、68个良性和22个未确定）。当评估单独的模式时，PET分别发现CT和MRI遗漏的病变有31个和12个，CT和MRI分别比PET多发现38个和61个病变。与CT相比，MRI多发现40个病变，遗漏8个。在集成模式下，PET/CT正确检测出PET/MRI误诊的6个病变，但在PET/MRI检测出的30例病例中呈假阴性。PET/MRI与PET/CT的总体诊断结果无差异。PET/MRI检测到的病变的SUVmax略高于PET/CT，但相关性良好（ρ = 0.85 - 0.91）。
结论/意义：新型集成PET/MRI在病变检测和定量测量方面与PET/CT表现相当。尽管硬件存在差异，但两种扫描模式下的PET提供的信息几乎相同。需要进一步研究以探索本研究未涉及的集成PET/MRI的特征。
