MR perfusion and diffusion imaging in the follow-up of recurrent glioblastoma treated with dendritic cell immunotherapy: a pilot study.
BACKGROUND
This study aims to determine the potential value of MR-PWI and MR-DWI to differentiate immune therapy-induced inflammatory response from recurrent glioblastoma tumour growth. Both can present as contrast-enhancing lesions on conventional magnetic resonance imaging (MRI).


METHODS
Patients with recurrent glioblastoma who could obtain a total or near-total resection were treated with dendritic cell immune therapy according to the HGG-IMMUNO-2003 trial. A retrospective analysis of 32 follow-up MRI examinations (mean follow-up time 21 months) in eight patients was performed for this pilot study. For the statistical analysis, the 32 examinations were divided into three groups: 0-obtained in patients that remained stable during the follow-up period, 1a-obtained in progressive-tumour patients at time points before definite progression and 1b-obtained in patients at or after progression.


RESULTS
Maximum lesional rCBV ratios were highest in group 1b (Student t test, 9.25 ± 2.68; p < 0.001) and were higher in group 1a (4.87 ± 1.61, p < 0.001) compared to group 0 (1.22 ± 0.47). The minimum apparent diffusion coefficients (ADCs) in the contrast-enhancing regions were lower in group 1a (0.62 ± 0.06 × 10(-3) mm(2)/s) than in group 0 (1.03 ± 0.43 × 10(-3) mm(2)/s, p = 0.01) and higher in group 1b (0.76 ± 0.08) compared to 1a (p = 0.02). The minimum ADCs in the FLAIR-hyperintense region were lower in group 1a (0.62 ± 0.06, p = 0.02) compared to group 0 (0.76 ± 0.16) but not significantly different in group 1b (0.68 ± 0.07) from groups 0 and 1a (p = 0.33, p = 0.10). The mean ADCs of the FLAIR-hyperintense region and the mean ADCs of the contrast-enhancing lesion were not significantly different.


CONCLUSIONS
The maximum lesional rCBV ratios and minimum ADC values in the contrast-enhancing area are potential radiological markers to differentiate between immune therapy-induced inflammatory response and recurrent glioblastoma tumour growth in glioblastoma patients treated with immune therapy.
Department of Radiology, University Clinical Center Ljubljana, Zaloška 7, 1000, Ljubljana, Slovenia. vrabec.m@gmail.com
Matej
M
Vrabec
Sofie
S
Van Cauter
Uwe
U
Himmelreich
Stefaan W
SW
Van Gool
Stefan
S
Sunaert
Steven
S
De Vleeschouwer
Dušan
D
Suput
Philippe
P
Demaerel
D000328:Adult; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000473:pathology / Q000628:therapy*; D003287:Contrast Media; D003713:Dendritic Cells; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000473:pathology / Q000628:therapy*; D006801:Humans; D007089:Image Enhancement; D007167:Immunotherapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D010865:Pilot Projects; D016896:Treatment Outcome
D003287:Contrast Media