Rodriguez M
Department of Diagnostic Radiology, University Hospital, Uppsala, Sweden.
Acta Radiol Suppl. 1998;417:1-36.
Certain aspects of the use of CT, MR imaging and PET were evaluated in patients with non-Hodgkin's lymphoma (NHL) with the aim of determining whether these methods may provide practical guidance for improving the management of these patients. Subjective evaluation of the tumor pattern on CT images, and quantification of tracer uptake using 11C methionine (11C Met) and [18F] fluorodeoxyglucose (18FDG) PET in patients with NHL, were performed to determine their relations to malignancy grade. An inhomogeneous tumor pattern (I) was found on CT in 75% of high-grade tumors, whereas 68% of low-grade tumors were homogeneous (H). Sixteen (94%) of the 17 tumors with a severely inhomogeneous pattern (I) were high-grade NHL, while 22 (72%) of the 29 homogeneous tumors (H) were low-grade. All tumors were clearly visualized with both 11C Met and 18FDG PET. The uptake values for 18FDG were significantly-higher in high- than in low-grade tumors, while no significant differences between the prognostic groups were found for 11C Met. A subjective evaluation of the tumor pattern on CT and on MR images was performed. An inhomogeneity index (IH8) was also used in MR images to make a quantitative assessment of the degree of inhomogeneity to determine their relation to prognosis. Patients with localized NHL, treated with radiotherapy, had an excellent prognosis irrespective of the degree of inhomogeneity, while patients with generalized disease, treated with chemotherapy, had a poor prognosis if the tumors were heterogeneous. Among chemotherapy-treated patients, all 9 patients with high IH8 values (> 2.56) on MR images and 9 out of 11 patients with severe inhomogeneities on CT images died. All patients with gastric NHL except for one patient with low-grade NHL of the MALT type displayed high 18FDG uptake at PET corresponding to the pathological findings at endoscopy and/or CT. 18FDG correctly excluded gastric NHL in a patient with benign gastric ulcer, but was unable to discriminate between gastric NHL and gastric carcinoma. The results suggest that 18FDG PET may demonstrate the extension of NHL in the gastric wall more accurately than CT and endoscopy. The prognostic importance of the size of a residual mass after completion of chemotherapy, and of tumor regression rates during chemotherapy, was evaluated in patients with high-grade NHL. Neither a large tumor size before treatment nor a large residual tumor after treatment correlated with relapse. It appears, however, as if the response rate halfway through the therapy may predict the recurrence rate, although statistical significance was not reached.
对非霍奇金淋巴瘤（NHL）患者使用CT、磁共振成像（MR）和正电子发射断层显像（PET）的某些方面进行了评估，目的是确定这些方法是否可为改善这些患者的管理提供实用指导。对CT图像上的肿瘤模式进行主观评估，并对NHL患者使用11C-蛋氨酸（11C Met）和[18F]氟脱氧葡萄糖（18FDG）PET对示踪剂摄取进行定量分析，以确定它们与恶性程度的关系。在CT上，75%的高级别肿瘤表现为不均匀肿瘤模式（I），而68%的低级别肿瘤为均匀模式（H）。17例具有严重不均匀模式（I）的肿瘤中有16例（94%）为高级别NHL，而29例均匀肿瘤（H）中有22例（72%）为低级别。11C Met和18FDG PET均能清晰显示所有肿瘤。18FDG的摄取值在高级别肿瘤中显著高于低级别肿瘤，而11C Met在不同预后组之间未发现显著差异。对CT和MR图像上的肿瘤模式进行了主观评估。还在MR图像中使用不均匀性指数（IH8）对不均匀程度进行定量评估，以确定其与预后的关系。接受放疗的局限性NHL患者，无论不均匀程度如何，预后均良好；而接受化疗的广泛性疾病患者，如果肿瘤为异质性，则预后较差。在接受化疗的患者中，MR图像上IH8值高（>2.56）的9例患者以及CT图像上有严重不均匀性的11例患者中的9例均死亡。除1例MALT型低级别NHL患者外，所有胃NHL患者在PET上均显示18FDG摄取高，与内镜检查和/或CT的病理结果相符。18FDG正确排除了1例良性胃溃疡患者的胃NHL，但无法区分胃NHL和胃癌。结果表明，18FDG PET可能比CT和内镜检查更准确地显示胃NHL在胃壁中的扩展情况。对高级别NHL患者化疗结束后残留肿块大小以及化疗期间肿瘤消退率的预后重要性进行了评估。治疗前肿瘤体积大以及治疗后残留肿瘤大均与复发无关。然而，似乎治疗中期的缓解率可能预测复发率，尽管未达到统计学显著性。
