Abstract
BACKGROUND AND PURPOSE: The accuracy of tumor plasma volume and Ktrans estimates obtained with DCE MR imaging may have inaccuracies introduced by a poor estimation of the VIF. In this study, we evaluated the diagnostic accuracy of a novel technique by using a phase-derived VIF and “bookend” T1 measurements in the preoperative grading of patients with suspected gliomas.
MATERIALS AND METHODS: This prospective study included 46 patients with a new pathologically confirmed diagnosis of glioma. Both magnitude and phase images were acquired during DCE MR imaging for estimates of Ktrans_ϕ and Vp_ϕ (calculated from a phase-derived VIF and bookend T1 measurements) as well as Ktrans_SI and Vp_SI (calculated from a magnitude-derived VIF without T1 measurements).
RESULTS: Median Ktrans_ϕ values were 0.0041 minutes−1 (95 CI, 0.00062–0.033), 0.031 minutes−1 (0.011–0.150), and 0.088 minutes−1 (0.069–0.110) for grade II, III, and IV gliomas, respectively (P ≤ .05 for each). Median Vp_ϕ values were 0.64 mL/100 g (0.06–1.40), 0.98 mL/100 g (0.34–2.20), and 2.16 mL/100 g (1.8–3.1) with P = .15 between grade II and III gliomas and P = .015 between grade III and IV gliomas. In differentiating low-grade from high-grade gliomas, AUCs for Ktrans_ϕ, Vp_ϕ, Ktrans_SI, and Vp_SI were 0.87 (0.73–1), 0.84 (0.69–0.98), 0.81 (0.59–1), and 0.84 (0.66–0.91). The differences between the AUCs were not statistically significant.
CONCLUSIONS: Ktrans_ϕ and Vp_ϕ are parameters that can help in differentiating low-grade from high-grade gliomas.
ABBREVIATIONS:
- AUC
- area under the receiver operating characteristic curve
- CT(t)
- tissue contrast concentration curve with time
- CI
- confidence interval
- CV
- coefficient of variation
- DCE
- dynamic contrast-enhanced
- Ktrans_ϕ
- volume transfer coefficient obtained from phase-derived vascular input function
- Ktrans_SI
- volume transfer coefficient obtained from magnitude-derived vascular input function
- NPV
- negative predictive value
- PPV
- positive predictive value
- R1
- rate of longitudinal relaxation
- R2*
- observed rate of transverse relaxation
- ROC
- receiver operating characteristic analysis
- T1
- longitudinal relaxation time
- Vp_SI
- plasma volume obtained from magnitude-derived vascular input function
- VIF
- vascular input function
- Vp_ϕ
- plasma volume obtained from phase-derived vascular input function
- © 2012 by American Journal of Neuroradiology