Abstract：
The recent introduction of integrated PET-MRI systems into practice seems promising in oncologic imaging, and efforts are made to specify their added values. The current study evaluates the added values of PET-MRI over PET-CT in detecting active malignant hepatic lesions.
As part of an ongoing prospective study in our institution that assesses the added values of PET-MRI, subjects undergo PET-CT and subsequent PET-MRI after single radiotracer injection. The current study included 97 pairs of whole-body PET-CT and liver PET-MRI scans, of 61 patients (19/61 had ≥ 2 paired scans), all performed with [18F]FDG and interpreted as showing active malignant hepatic involvement. Primary malignancies were of colorectal/biliary/pancreatic/breast/other origins in 19/9/9/7/17 patients. Monitoring response to therapy was the indication in 86/97 cases. When PET-MRI detected additional malignant lesions over PET-CT, lesions size, their characteristics on PET-MRI, and the influence on the final report were recorded.
In 37/97 (38.1%) cases, a total of 78 malignant lesions were identified on PET-MRI but not on PET-CT: 19 lesions (11 cases) were identified on PET of PET-MRI but not on PET of PET-CT; 37 lesions (14 cases) were small (≤ 0.8 cm) and identified on MRI only; 22 lesions (12 cases) were > 0.8 cm, had low/no [18F]FDG uptake, but were categorized as viable based on MRI. These 78 lesions caused major effect on final reports in 11/97 (11.3%) cases, changing reported response assessment category (10/86 cases) or defining malignant hepatic disease on staging/restaging scans (1/11 cases).
PET-MRI offers several advantages over PET-CT in assessing the extent and response to therapy of malignant hepatic involvement. Additional malignant lesions detected on PET-MRI are attributed to superior PET performance (compared with PET of PET-CT), greater spatial resolution provided by MRI, and improved multi-parametric viability assessment. In around one-tenth of cases, findings identified on PET-MRI but not on PET-CT significantly change the final report\'s conclusion.
As part of an ongoing prospective study in our institution that assesses the added values of PET-MRI, subjects undergo PET-CT and subsequent PET-MRI after single radiotracer injection. The current study included 97 pairs of whole-body PET-CT and liver PET-MRI scans, of 61 patients (19/61 had ≥ 2 paired scans), all performed with [18F]FDG and interpreted as showing active malignant hepatic involvement. Primary malignancies were of colorectal/biliary/pancreatic/breast/other origins in 19/9/9/7/17 patients. Monitoring response to therapy was the indication in 86/97 cases. When PET-MRI detected additional malignant lesions over PET-CT, lesions size, their characteristics on PET-MRI, and the influence on the final report were recorded.
In 37/97 (38.1%) cases, a total of 78 malignant lesions were identified on PET-MRI but not on PET-CT: 19 lesions (11 cases) were identified on PET of PET-MRI but not on PET of PET-CT; 37 lesions (14 cases) were small (≤ 0.8 cm) and identified on MRI only; 22 lesions (12 cases) were > 0.8 cm, had low/no [18F]FDG uptake, but were categorized as viable based on MRI. These 78 lesions caused major effect on final reports in 11/97 (11.3%) cases, changing reported response assessment category (10/86 cases) or defining malignant hepatic disease on staging/restaging scans (1/11 cases).
PET-MRI offers several advantages over PET-CT in assessing the extent and response to therapy of malignant hepatic involvement. Additional malignant lesions detected on PET-MRI are attributed to superior PET performance (compared with PET of PET-CT), greater spatial resolution provided by MRI, and improved multi-parametric viability assessment. In around one-tenth of cases, findings identified on PET-MRI but not on PET-CT significantly change the final report\'s conclusion.
摘要：
目的：最近将集成的PET-MRI系统引入实践中，在肿瘤成像中似乎很有希望，并努力确定其附加值。当前的研究评估了PET-MRI相对于PET-CT在检测活动性恶性肝病变中的附加值。
方法：作为我们机构正在进行的前瞻性研究的一部分，该研究评估了PET-MRI的附加值，受试者在单次放射性示踪剂注射后接受PET-CT和随后的PET-MRI检查.目前的研究包括97对全身PET-CT和肝脏PET-MRI扫描，61例患者（19/61有≥2次配对扫描），全部用[18F]FDG进行，并解释为显示活跃的恶性肝脏受累。在19/9/9/7/17患者中，原发性恶性肿瘤为结直肠/胆道/胰腺/乳腺/其他起源。在86/97例中，监测对治疗的反应是指征。当PET-MRI在PET-CT上检测到额外的恶性病变时，病变大小,它们在PET-MRI上的特征，并记录对最终报告的影响。
结果：在37/97（38.1%）病例中，共有78个恶性病变在PET-MRI上，但在PET-CT上未发现：19个病变（11例）在PET-MRI的PET上，但在PET-CT的PET上未发现；37个病变（14例）小（≤0.8cm），仅在MRI上发现；22个病变（12例）>0.8cm，具有低/无[18F]FDG摄取，但根据MRI被归类为可行的。这78个病变对11/97例（11.3％）的最终报告产生了重大影响，改变报告的反应评估类别（10/86例）或在分期/重新分类扫描中定义恶性肝病（1/11例）。
结论：在评估恶性肝脏受累的程度和治疗反应方面，PET-MRI与PET-CT相比具有若干优势。在PET-MRI上发现的其他恶性病变归因于优越的PET性能（与PET-CT的PET相比），MRI提供了更高的空间分辨率，改进了多参数生存能力评估。在大约十分之一的案例中，在PET-MRI而不是PET-CT上发现的结果显着改变了最终报告的结论。
方法：作为我们机构正在进行的前瞻性研究的一部分，该研究评估了PET-MRI的附加值，受试者在单次放射性示踪剂注射后接受PET-CT和随后的PET-MRI检查.目前的研究包括97对全身PET-CT和肝脏PET-MRI扫描，61例患者（19/61有≥2次配对扫描），全部用[18F]FDG进行，并解释为显示活跃的恶性肝脏受累。在19/9/9/7/17患者中，原发性恶性肿瘤为结直肠/胆道/胰腺/乳腺/其他起源。在86/97例中，监测对治疗的反应是指征。当PET-MRI在PET-CT上检测到额外的恶性病变时，病变大小,它们在PET-MRI上的特征，并记录对最终报告的影响。
结果：在37/97（38.1%）病例中，共有78个恶性病变在PET-MRI上，但在PET-CT上未发现：19个病变（11例）在PET-MRI的PET上，但在PET-CT的PET上未发现；37个病变（14例）小（≤0.8cm），仅在MRI上发现；22个病变（12例）>0.8cm，具有低/无[18F]FDG摄取，但根据MRI被归类为可行的。这78个病变对11/97例（11.3％）的最终报告产生了重大影响，改变报告的反应评估类别（10/86例）或在分期/重新分类扫描中定义恶性肝病（1/11例）。
结论：在评估恶性肝脏受累的程度和治疗反应方面，PET-MRI与PET-CT相比具有若干优势。在PET-MRI上发现的其他恶性病变归因于优越的PET性能（与PET-CT的PET相比），MRI提供了更高的空间分辨率，改进了多参数生存能力评估。在大约十分之一的案例中，在PET-MRI而不是PET-CT上发现的结果显着改变了最终报告的结论。
