Article
Thallium-201-SPECT demonstrates excellent sensitivity and specificity to differentiate tumour recurrence from treatment-related changes in re-operated cases of glioblastoma after radiochemotherapy
Thallium-201-SPECT zeigt gute Sensitivität und Spezifität zur Differenzierung von Tumorprogression gegenüber Radionekrose/Pseudoprogression bei re-operierten Patienten mit Glioblastom nach Radiochemotherapie
Search Medline for
Authors
Published: | May 25, 2022 |
---|
Outline
Text
Objective: Distinguishing treatment related changes (TRC) from tumour progression is still challenging, especially regarding the limits of standard MR imaging and application of RANO criteria. The aim of this work is to analyze the sensitivity and specificity of additionally Thallium 201 (201T1) single-photon emission computed tomography (SPECT) in the prediction of neuropathological proved recurrence in a case series of re-operated glioblastomas after standard radio-chemotherapy.
Methods: Inclusion criteria: Patients with diagnosis of Glioblastoma WHO °IV, surgical tumour removal, radio-chemotherapy, suspected glioblastoma recurrence by standard or multimodal MR imaging, 201T1-SPECT examination and neurosurgical re-operation. 201T1-SPECT images were re-evaluated in a semi-quantitative manner using 4 different ratios (Q1-4) based on manually drawn 3 region of interests (ROIs) (ROI1: suspected tumour, ROI2: contralateral mirror and ROI3: scalp), Q1 = ROI1max/ROI2 max, Q2= ROI1average /ROI2 average, Q3= ROI1 max /ROI3 max und Q4= ROI1average /ROI3 average. The definitive diagnosis in all patients was based on neuropathological examination.
Results: 201T1-SPECT was performed in 82 cases of suspected recurrence of glioblastoma. Of those 82 cases, 20 patients underwent surgical re-intervention (11 male, 9 female). Mean age was 57 years (40-74 years), near-total or subtotal tumour removal was performed in 19 patients, biopsy was performed in one patient. Definitive neuropathological diagnosis was recurrent tumour in 17 patients; however treatment related changes in terms of radiation necrosis were demonstrated in 3 patients. A significant correlation was found between the 201T1-SPECT results (using all ratios Q1-Q4) and the histological diagnosis (p < 0.05, Spearman test). Sensitivity and specificity of Thallium-SPECT was found to be 94.1% and 100% respectively.
Conclusion: In this case series of 20 re-operated patients, 201T1-SPECT could accurately differentiate tumour recurrence from TRC / radiation necrosis in patients with glioblastoma and MR criteria of tumour progression after radio-chemotherapy. The limitation of this study is clearly the low number of cases; however the results shown here could be used as a basis for further retrospective and prospective studies, focussing on 201T1-SPECT cut off values and integrating further data, especially survival and correlation with multimodal MR imaging.