|ECR 2019 / C-2567|
|Using ASL-perfusion to detection of residual glioblastoma tissue after surgical treatment|
Methods and materials
56 patients were included — 32 men (57.1%) and 24 women (42.9%) after 2-4 weeks surgical removal of glioblastoma (WHO GRADE IV), prior to the course of radiotherapy. The average age of patients was 56.9 ± 10.9 years (min- 31 years, max- 79 years), there were no significant differences in age between the examined men and women (56.1 ± 11.2 years in men, 58.1 ± 10.8 years in women, p = 0.45).
MRI studies were performed on a 1.5T magnetic induction device (Optima MR450w, GE Healthcare) using a 24-channel head coil. The study protocol included the usual T2, T1, FLAIR and DWI. All sequences had strictly axial slice positioning, 4 mm thick and 0 mm inter-slice spacing. ASL perfusion was performed by pseudo-continuous 3D labeling of arterial spins (pcASL) with the following parameters: TR time - 4710 ms; TE echo time –11.3 ms; spatial resolution - 512x8; the number of signal averages (NEX) - 4; field of view (FOV) - 24 cm; the number of sections - 40; slice thickness 4 mm; intercut interval 0 mm; Label delay after label (PLD) - 1.525 ms. In addition, post-contrast images were obtained in the T1-VI mode in the axial plane and multiplanar T1-3D Cube with a slice thickness of 1 mm. The dose of the contrast agent was 0.2 ml x kg (Gadodiamide 0.5 mmol). The total study time was 24 minutes.
All patients had pathological areas of accumulation of a contrast agent in the peripheral and nearby parts of the postoperative defect of brain tissue.
The average CBF values were determined in 3 different areas of interest (ROI, up to 0.5 cm2) – in area of maximum perfusion (presumptive tumor tissue), in the postoperative scar tissue and in the deep white matter (at the level of the semioval centers) of opposite hemisphere (Fig. 1).
The normal CBF value of brain’s gray matter ranges from 37 to 65 ml/100gr/min (8,9). As the cutoff point of CBF for diagnosis residual tumor tissue we used the upper threshold value of CBF of the brain gray matter.
For statistical analysis IBM SPSS Statistics 23 was used. Differences between the groups were tested for significance by a Mann — Whitney U-test. P-value of less than 0.05 was considered to indicate statistically significant difference.
Thematically related posters
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