Abstract
BACKGROUND AND PURPOSE: Dynamic contrast-enhanced MR imaging parameters can be biased by poor measurement of the vascular input function. We have compared the diagnostic accuracy of dynamic contrast-enhanced MR imaging by using a phase-derived vascular input function and “bookend” T1 measurements with DSC MR imaging for preoperative grading of astrocytomas.
MATERIALS AND METHODS: This prospective study included 48 patients with a new pathologic diagnosis of an astrocytoma. Preoperative MR imaging was performed at 3T, which included 2 injections of 5-mL gadobutrol for dynamic contrast-enhanced and DSC MR imaging. During dynamic contrast-enhanced MR imaging, both magnitude and phase images were acquired to estimate plasma volume obtained from phase-derived vascular input function (Vp_Φ) and volume transfer constant obtained from phase-derived vascular input function (Ktrans_Φ) as well as plasma volume obtained from magnitude-derived vascular input function (Vp_SI) and volume transfer constant obtained from magnitude-derived vascular input function (Ktrans_SI). From DSC MR imaging, corrected relative CBV was computed. Four ROIs were placed over the solid part of the tumor, and the highest value among the ROIs was recorded. A Mann-Whitney U test was used to test for difference between grades. Diagnostic accuracy was assessed by using receiver operating characteristic analysis.
RESULTS: Vp_ Φ and Ktrans_Φ values were lower for grade II compared with grade III astrocytomas (P < .05). Vp_SI and Ktrans_SI were not significantly different between grade II and grade III astrocytomas (P = .08–0.15). Relative CBV and dynamic contrast-enhanced MR imaging parameters except for Ktrans_SI were lower for grade III compared with grade IV (P ≤ .05). In differentiating low- and high-grade astrocytomas, we found no statistically significant difference in diagnostic accuracy between relative CBV and dynamic contrast-enhanced MR imaging parameters.
CONCLUSIONS: In the preoperative grading of astrocytomas, the diagnostic accuracy of dynamic contrast-enhanced MR imaging parameters is similar to that of relative CBV.
ABBREVIATIONS:
- DCE
- dynamic contrast-enhanced
- Ktrans_Φ
- volume transfer constant obtained from phase-derived vascular input function
- Ktrans_SI
- volume transfer constant obtained from magnitude-derived vascular input function
- rCBV
- relative CBV
- SI
- signal intensity
- VIF
- vascular input function
- Vp
- plasma volume
- Vp_Φ
- plasma volume obtained from phase-derived vascular input function
- Vp_SI
- plasma volume obtained from magnitude-derived vascular input function
- © 2015 by American Journal of Neuroradiology