Fig 1.
Flow chart of the study population.
Note: MRI = magnetic resonance imaging, CCRT = concurrent chemoradiotherapy, TMZ = temozolomide, GBM = glioblastoma multiforme.
Fig 2.
Timeline of patient treatment and the imaging study.
The standard treatment for newly diagnosed GBM includes gross total removal of the tumor and concurrent chemoradiotherapy with temozolomide, followed by adjuvant temozolomide. In this study, we enrolled patients who underwent pre- and post-radiation brain MRI including R1 map source images. Pre-radiation MRI included MRI performed either before or after tumor removal. The mean time interval between pre- and post-radiation MRI session was 4.2 ± 2.1 months. Further follow-up brain MRI with R1 mapping was available for 10 patients.
Fig 3.
A 28-year-old male patient with severe headache for 1 month underwent brain MR imaging. (a) Contrast-enhanced axial T1WI revealed a heterogeneous enhancing mass located at the right frontal lobe. He underwent gross total removal of the brain tumor, and final pathology confirmed GBM. He also completed radiotherapy (total dose = 61.2 Gy). (b) The black line (arrows) in the radiotherapy plan map showed the iso-dose line of 3600 cGy, which was the 56.7% iso-dose line of the maximum dose (6343.8 cGy). For R1 measurement, the ROI was drawn at the peri-tumoral area located within the 50–100% iso-dose line of the maximum dose and both (c) overt enhancing area and (d) abnormal T2 hypersignal intensity area were avoided.
Fig 4.
Definition of AreaH and AreaL.
A 58-year-old female patient underwent radiotherapy for the treatment of GBM located in the right frontal lobe. The radiotherapy plan map was obtained from the electronic medical records system (EMR) and was composed of representative (a) axial, (b) coronal, and sagittal (not presented) CT images (note; arrows represent the iso-dose line of 3600 cGy). In this patient, (c) the right thalamus (dashed circle) was designated as a AreaH, whereas (d) the left frontal white matter (dashed circle) was considered a AreaL (presented images: pre-contrast T1WI).
Table 1.
Basic information regarding patients, target lesions, treatment, and imaging work-up in 44 patients with supratentorial GBM.
Table 2.
R1 of each brain area and peri-tumoral area.
Table 3.
R1 change in each brain area according to radiation dose.
Table 4.
Univariate linear regression analyses regarding the peri-tumoral R1 changes.