| Abstrakt: |
Purpose: Stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) are frequently employed in cerebral metastasis treatment. Dynamic susceptibility (DSC) and dynamic contrast enhancement (DCE) have potential to distinguish very early tumor response prior to structural imaging changes. We sought to determine whether early relative blood volume (rCBV), blood flow (rCBF) or permeability (rK2trans) distinguish treatment response. Methods: Baseline, one week, and one month DSC and DCE were obtained for 46 patients (70 tumors) treated with SRS or WBRT. Tumor and contra-lateral regions were segmented. Outcome was determined at 1 year on follow-up structural MRI. Volume increase ≥71.5% indicated progressive disease; increase <71.5% and decrease ≤58.5% stable disease and a decrease >58.5% treatment response. Uni and multivariate analysis was performed for tumor outcome. ROC analysis of rCBV, rCBF, rK2trans identified cut-off values with optimal sensitivity and specificity for outcome. Results: rK2trans distinguished progressive disease from treatment response at one week (P = 0.03) with optimal threshold value, sensitivity, specificity and AUC of 12.8, 69.2%, 63.6% and 67.4%. rCBF and rCBV at one month discriminated progressive from non-progressive disease (P <0.05 each) with optimal threshold values, sensitivity, specificity and AUC of 2.09, 87.5%, 66,7%, 74.2% and 3.08, 82.8%, 81.8%, 84.3%, respectively. Logistic regression at one week identified elevated rK2trans, absence of prior radiation and steroid administration at one week, and elevated rCBV at one month and no previous radiation therapy as early predictors of tumor non-progression. At one month only rCBV was predictive. Conclusion: Early rK2trans and rCBV measures predict tumor response following high dose radiation therapy. Disclosure: No significant relationships. [ABSTRACT FROM AUTHOR] |
