Magnetic resonance imaging-based tumour perfusion parameters are biomarkers predicting response after radiation to brain metastases.

PURPOSE: To investigate whether early relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF) and permeability (Ktrans(2)) measurements may serve as magnetic resonance imaging (MRI) biomarkers of radiation response or progression for brain metastases. MATERIALS AND METHODS: Seventy brain metastases in 44 patients treated with either stereotactic radiosurgery or whole brain radiotherapy were imaged with dynamic susceptibility and dynamic contrast enhancement MRI at baseline, 1 week and 1 month after treatment. The final response status was determined according to volume criteria derived from a 1 year post-treatment MRI or last available follow-up MRI. Tumours were characterised as responders, non-responders, progressors and non-progressors and compared for Ktrans(2), rCBF and rCBV differences. Uni- and multivariate analysis evaluated factors associated with tumour response and progression at 1 week and 1 month. A generalised estimating equations (GEE) model accounted for multiple tumours per subject. Receiver operator characteristic (ROC) analysis identified optimal cut-off values, sensitivity and specificity for response or progression. RESULTS: Tumour responders showed lower Ktrans(2) and reduced rCBF at 1 week (P < 0.05 each). Progressive disease showed lower rCBF and reduced rCBV at 1 month (P < 0.05 each). GEE and multivariate analysis revealed lower Ktrans(2) at 1 week, an absence of prior radiation predicted response. At 1 month only lower rCBV predicted progressive disease on GEE and multivariate analysis. Optimal cut-off points for Ktrans(2) and rCBV were 1.37 and 2.03 with sensitivity and specificity of 61.5 and 81.1% and 73.9 and 81.8%, respectively. CONCLUSION: Lower Ktrans(2) at 1 week and rCBV at 1 month discriminated responders and progressive disease, respectively.

Non Tumor Perfusion Changes Following Stereotactic Radiosurgery to Brain Metastases.

Purpose: To evaluate early perfusion changes in normal tissue following stereotactic radiosurgery (SRS). Methods: Nineteen patients harboring twenty-two brain metastases treated with SRS were imaged with dynamic susceptibility magnetic resonance imaging (DSC MRI) at baseline, 1 week and 1 month post SRS. Relative cerebral blood volume and flow (rCBV and rCBF) ratios were evaluated outside of tumor within a combined region of interest (ROI) and separately within gray matter (GM) and white matter (WM) ROIs. Three-dimensional dose distribution from each SRS plan was divided into six regions: (1) <2 Gy; (2) 2-5 Gy; (3) 5-10 Gy; (4) 10-12 Gy; (5) 12-16 Gy; and (6) >16 Gy. rCBV and rCBF ratio differences between baseline, 1 week and 1 month were compared. Best linear fit plots quantified normal tissue dose-dependency. Results: Significant rCBV ratio increases were present between baseline and 1 month for all ROIs and dose ranges except for WM ROI receiving <2 Gy. rCBV ratio for all ROIs was maximally increased from baseline to 1 month with the greatest changes occurring within the 5-10 Gy dose range (53.1%). rCBF ratio was maximally increased from baseline to 1 month for all ROIs within the 5-10 Gy dose range (33.9-45.0%). Both rCBV and rCBF ratios were most elevated within GM ROIs. A weak, positive but not significant association between dose, rCBV and rCBF ratio was demonstrated. Progressive rCBV and rCBF ratio increased with dose up to 10 Gy at 1 month. Conclusion: Normal tissue response following SRS can be characterized by dose, tissue, and time specific increases in rCBV and rCBF ratio.

Traumatic intracranial hematomas: prognostic value of contrast extravasation.

BACKGROUND AND PURPOSE: Contrast extravasation within spontaneous intracranial hemorrhage is a well-described predictor of hematoma growth, poor clinical outcome, and mortality. The purpose of this study was to assess the prognostic value of contrast extravasation in acute traumatic intracranial hematomas. MATERIALS AND METHODS: In our institution, CTA (including PCCT) is the primary screening technique for cervical vascular injuries. Sixty consecutive patients with at least 1 acute intracranial hematoma (ICH, subdural hematoma, and/or epidural hematoma) meeting predefined size criteria, with CTA/PCCT performed within 24 hours of admission and follow-up CT within 72 hours of admission, were retrospectively evaluated for CE by 2 observers. The predictive value of CE for a composite outcome (hematoma expansion, need for hematoma evacuation, in-hospital mortality) was evaluated on a per-patient basis. Interobserver agreement for CE and the association between baseline variables and outcome were also examined. Different patterns of extravasation were evaluated on a per-lesion basis, with outcomes including hematoma expansion and evacuation. RESULTS: CE was present in 30 (50%) patients with almost perfect interobserver agreement (κ=0.87; 95% CI, 0.74-0.99). The per-patient multivariate analysis showed independent association of midline shift (P=.020), Glasgow Coma Scale score≤8 (P=.024), and CE (P=.017), with poor outcome and demonstrated a trend toward poor outcome prediction for age 65 years or older (P=.050). In the per-lesion analysis, only extravasation identified on CTA (active and contained extravasation) was associated with hematoma expansion and evacuation. CONCLUSIONS: Contrast extravasation within intracranial hematomas predicts poor in-hospital outcome in the setting of acute traumatic intracranial injuries.