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Assessment of irradiated brain metastases using dynamic contrast-enhanced magnetic resonance imaging
Ist Teil von
Neuroradiology, 2014-06, Vol.56 (6), p.437-443
Ort / Verlag
Berlin/Heidelberg: Springer Berlin Heidelberg
Erscheinungsjahr
2014
Quelle
SpringerLink
Beschreibungen/Notizen
Introduction
The purpose of this study was to evaluate the effect of stereotactic radiosurgery (SRS) on cerebral metastases using the transfer constant (
K
trans
) assessed by dynamic contrast-enhanced (DCE) MRI. Furthermore, we aimed to evaluate the ability of
K
trans
measurements to predict midterm tumor outcomes after SRS.
Methods
The study received institutional review board approval, and informed consent was obtained from all subjects. Twenty-six adult patients with a total of 34 cerebral metastases underwent T1-weighted DCE MRI in a 1.5-T magnet at baseline (prior to SRS) and 4–8 weeks after treatment. Quantitative analysis of DCE MRI was performed by generating
K
trans
parametric maps, and region-of-interest-based measurements were acquired for each metastasis. Conventional MRI was performed at least 16 weeks after SRS to assess midterm tumor outcome using volume variation.
Results
The mean (±SD)
K
trans
value was 0.13 ± 0.11 min
−1
at baseline and 0.08 ± 0.07 min
−1
after 4–8 weeks post-treatment (
p
< 0.001). The mean (±SD) total follow-up time was 7.9 ± 4.7 months. Seventeen patients (22 lesions) underwent midterm MRI. Of those, nine (41 %) lesions had progressed at the midterm follow-up. An increase in
K
trans
after SRS was predictive of tumor progression (hazard ratio = 1.50; 95 % CI = 1.16–1.70,
p
< 0.001). An increase of 15 % in
K
trans
showed a sensitivity of 78 % and a specificity of 85 % for the prediction of progression at midterm follow-up.
Conclusion
SRS was associated with a reduction of
K
trans
values of the cerebral metastases in the early post-treatment period. Furthermore,
K
trans
variation as assessed using DCE MRI may be helpful to predict midterm outcomes after SRS.