Bader J B, Samnick S, Moringlane J R, Feiden W, Schaefer A, Kremp S, Kirsch C M
Department of Nuclear Medicine, Saarland University Medical Center, Homburg/Saar Germany.
Eur J Nucl Med. 1999 Feb;26(2):144-51. doi: 10.1007/s002590050370.
Based on the results of stereotactic biopsy, we evaluated in a prospective fashion the efficiency of l-3-[123I]iodo-alpha-methyltyrosine-single-photon emission tomography (SPET) and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the detection and grading of recurrences in patients previously treated for gliomas. The patient population comprised 30 individuals, nine with astrocytomas of grade II, ten with astrocytomas of grade IV, three with oligoastrocytomas of grade II, six with oligodendrogliomas of grade II and two with anaplastic oligodendrogliomas of grade III) suspected of recurrence and scheduled for further treatment. IMT SPET data were acquired using either by dual-or a triple-headed SPET camera, Multispect 2/3. FDG uptake was measured with an ECAT ART PET camera. Two independent observers classified PET and SPET images as positive or negative for tumour tissue. Uptake of FDG and IMT was evaluated visually and, in the case of IMT, also quantitatively by calculating the ratios between tracer accumulation in the lesion and the unaffected contralateral regions of reference using the region of interest (ROI) technique. The PET and SPET results were compared with the histopathological findings obtained either by stereotactic biopsy or in one case by open surgery. Glucose metabolism and amino acid uptake of recurrences of brain tumours as assessed by FDG-PET and IMT-SPET correlated highly with the histopathological findings. Based on the histopathological data, FDG-PET and IMT-SPET findings confirmed recurrence in all cases of high-grade gliomas (IV). A difference could be demonstrated in low-grade (II-III) tumour recurrences. True-positive IMT-SPET results were found in 86% of grade III and 75% of grade II recurrences, whereas FDG-PET yielded a sensitivity of 71% in tumours of grade III and 50% in those of grade II. With respect to the grade of malignancy of brain tumours at recurrence, IMT-SPET, in contrast to FDG-PET, does not permit adequate in vivo grading of non-mixed brain tumours of astrocytic or oligodendroglial origin. However, in this study FDG-PET did not permit discrimination between upgrading of low-grade oligoastrocytomas (II) into anaplastic oligodendrogliomas (III) and upgrading into glioblastomas (IV) The results of this study indicate that FDG-PET and IMT-SPET are equivalent to stereotactic biopsy in their ability to identify high-grade tumours at recurrence. IMT-SPET proved to be superior to FDG-PET in confirming low-grade recurrences. In the case of suspected progression of the grade of malignancy in ordinary gliomas, FDG-PET correlated significantly with the histopathological grading, whereas IMT-SPET did not. However, tumour grading by FDG-PET has a limitation in mixed brain tumours in that it is not possible to discriminate between progression of the oligo- versus the astrocytic tumour entity. In this case histopathological evaluation of the tumour grade remains necessary.
基于立体定向活检的结果，我们前瞻性地评估了l-3-[123I]碘-α-甲基酪氨酸单光子发射断层扫描（SPET）和[18F]氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）在先前接受过胶质瘤治疗的患者复发检测及分级中的效率。患者群体包括30例个体，其中9例为Ⅱ级星形细胞瘤，10例为Ⅳ级星形细胞瘤，3例为Ⅱ级少突星形细胞瘤，6例为Ⅱ级少突胶质细胞瘤，2例为Ⅲ级间变性少突胶质细胞瘤，均怀疑复发并计划进一步治疗。IMT SPET数据使用双探头或三探头SPET相机Multispect 2/3采集。FDG摄取用ECAT ART PET相机测量。两名独立观察者将PET和SPET图像分类为肿瘤组织阳性或阴性。通过视觉评估FDG和IMT的摄取情况，对于IMT，还通过使用感兴趣区（ROI）技术计算病变中示踪剂积聚与未受影响的对侧参考区域之间的比值进行定量评估。将PET和SPET结果与通过立体定向活检或1例开颅手术获得的组织病理学结果进行比较。通过FDG-PET和IMT-SPET评估的脑肿瘤复发的葡萄糖代谢和氨基酸摄取与组织病理学结果高度相关。基于组织病理学数据，FDG-PET和IMT-SPET结果证实所有高级别胶质瘤（Ⅳ级）病例均复发。在低级别（Ⅱ-Ⅲ级）肿瘤复发中可显示出差异。在Ⅲ级复发中，86%的病例IMT-SPET结果为真阳性，在Ⅱ级复发中为75%，而FDG-PET在Ⅲ级肿瘤中的敏感性为71%，在Ⅱ级肿瘤中为50%。关于复发时脑肿瘤的恶性程度分级，与FDG-PET不同，IMT-SPET无法对星形细胞或少突胶质细胞起源的非混合性脑肿瘤进行充分的体内分级。然而，在本研究中，FDG-PET无法区分低级别少突星形细胞瘤（Ⅱ级）进展为间变性少突胶质细胞瘤（Ⅲ级）和进展为胶质母细胞瘤（Ⅳ级）。本研究结果表明，FDG-PET和IMT-SPET在识别复发的高级别肿瘤方面与立体定向活检能力相当。在确认低级别复发方面，IMT-SPET被证明优于FDG-PET。在普通胶质瘤怀疑恶性程度进展的情况下，FDG-PET与组织病理学分级显著相关，而IMT-SPET则不然。然而，FDG-PET对混合性脑肿瘤的分级存在局限性，因为无法区分少突胶质细胞瘤与星形细胞瘤实体的进展。在这种情况下，仍需要对肿瘤分级进行组织病理学评估。
