Utility of Dynamic Susceptibility Contrast Perfusion-Weighted MR Imaging and ¹¹C-Methionine PET/CT for Differentiation of Tumor Recurrence from Radiation Injury in Patients with High-Grade Gliomas

Abstract

BACKGROUND AND PURPOSE: Both 11 C-methionine PET/CT and DSC-PWI could be used to differentiate radiation injury from recurrent brain tumors. Our aim was to assess the performance of MET PET/CT and DSC-PWI for differentiation of recurrence and radiation injury in patients with high-grade gliomas and to quantitatively analyze the diagnostic values of PET and PWI parameters. MATERIALS AND METHODS: Forty-two patients with high-grade gliomas were enrolled in this study. The final diagnosis was determined by histopathologic analysis or clinical follow-up. PWI and PET parameters were recorded and compared between patients with recurrence and those with radiation injury using Student t tests. Receiver operating characteristic and logistic regression analyses were used to determine the diagnostic performance of each parameter. RESULTS: The final diagnosis was recurrence in 33 patients and radiation injury in 9. PET/CT showed a patient-based sensitivity and specificity of 0.909 and 0.556, respectively, while PWI showed values of 0.667 and 0.778, respectively. The maximum standardized uptake value, mean standardized uptake value, tumor-to-background maximum standardized uptake value, and mean relative CBV were significantly higher for patients with recurrence than for patients with radiation injury. All these parameters showed a high discriminative power in receiver operating characteristic analysis. The optimal cutoff values for the tumor-to-background maximum standardized uptake value and mean relative CBV were 1.85 and 1.83, respectively, and corresponding sensitivities and specificities for the diagnosis of recurrence were 0.97 and 0.667 and 0.788 and 0.88, respectively. Areas under the curve for the tumor-to-background maximum standardized uptake value and mean relative CBV were 0.847 Ϯ 0.077 and 0.845 Ϯ 0.078, respectively. Combined assessment of the tumor-to-background maximum standardized uptake value and mean relative CBV showed the largest area under the curve (0.953 Ϯ 0.031), with corresponding sensitivity and specificity of 0.848 and 1.0, respectively. CONCLUSIONS: Both 11 C-methionine PET/CT and PWI are equally accurate in the differentiation of recurrence from radiation injury in patients with high-grade gliomas, and a combination of the 2 modalities could result in increased diagnostic accuracy. ABBREVIATIONS: AUC ϭ area under the curve; MET ϭ 11 C-methionine; HGG ϭ high-grade glioma; max ϭ maximum; rCBV ϭ relative CBV; SUV ϭ standardized uptake value; TBR ϭ tumor-to-background G liomas are the most common primary brain tumors. Tumor resection followed by postoperative chemotherapy and radiation therapy is the primary treatment for gliomas. However, radiation therapy may damage normal brain tissue and result in adverse effects involving the brain. Classically, radiation injury can be classified into acute and delayed reactions. Radiation-induced necrosis is the most severe form of radiation injury and usually occurs 3-12 months after radiation therapy, though it can also occur years after treatment. The incid...

Clinical Imaging for Diagnostic Challenges in the Management of Gliomas: A Review

“…A direct comparison of MET versus FDG PET imaging obtained on the same day concluded that MET was more reliable in identifying recurrent tumor than FDG, and this has been confirmed by subsequent meta‐analysis . Combining MET‐PET and DCE perfusion imaging modalities similarly demonstrated significantly increased sensitivity and specificity for identifying TP . Nonetheless, the clinical use of MET is complicated by its short half‐life of 20 minutes, requiring an onsite cyclotron and precise coordination of its administration …”

Positron emission tomography with 11C-methionine in primary brain tumor diagnosis

“…Другие пытаются разграничить подтипы глиом с выделением опухолей, содержащих олигодендроглиальный компонент [23,25]. В целом исследователи с большой осторожностью используют ИН как единственный маркер именно степени анаплазии, чаще всего сравнивая его чувствительность и специфичность с такими МРТ-методиками, как диффузионно-взвешенные изображения и Т2*-перфузия [26]. В то же время практически все авторы сходятся во мнении, что высокие значения ИН (более 2,0) и особенно увеличение индекса в ходе динамического наблюдения за пациентом достоверно коррелируют с малигнизацией глиальных новообразований.…”

The Molecular Effects of Ionizing Radiations on Brain Cells: Radiation Necrosis vs. Tumor Recurrence

“…Moreover, in case of high-grade gliomas, 11 C-MET uptake is higher than in low-grade tumors therefore it could be used for monitoring purposes to assess anaplastic transformation [48]. In a recent study of 18 lesions from 15 patients with metastatic brain tumors who underwent gamma-knife radiosurgery, the authors showed that MET-PET was superior in terms of both sensitivity and specificity as imaging technique for differentiating RN and recurrent metastatic tumors after gamma-knife compared with diffusion weighted imaging (DWI), MR permeability imaging and FDG-PET, although it is not widely available yet for clinical use due to its physical limitations [49]. For the detection of tumor recurrence, compared to 201 Tl, 18 F-FDG is more specific but less sensitive since the former, prior to its uptake through the Na + -K + ATPase pump, has a non-specific accumulation due to BBB breakdown, whereas the latter lacks sensitivity because of the physiological uptake of normal brain [45].…”

“…Moreover, in case of high-grade gliomas, 11 C-MET uptake is higher than in low-grade tumors therefore it could be used for monitoring purposes to assess anaplastic transformation [48]. In a recent study of 18 lesions from 15 patients with metastatic brain tumors who underwent gamma-knife radiosurgery, the authors showed that MET-PET was superior in terms of both sensitivity and specificity as imaging technique for differentiating RN and recurrent metastatic tumors after gamma-knife compared with diffusion weighted imaging (DWI), MR permeability imaging and FDG-PET, although it is not widely available yet for clinical use due to its physical limitations [49].…”