For dynamic contrast-enhanced MRI studies in the human brain, it is useful to measure the venous output function (VOF). The purpose of this work was to explore the feasibility of measuring the VOF using the MR signal phase (in absolute units of gadolinium concentration) in the superior sagittal sinus. Phantom experiments were performed to validate the technique for different superior sagittal sinus angles (h 5 0-488 relative to the main magnetic field), different curvatures (straight or radius 5 45 mm), and different spatial resolutions (2.2-5.5 mm, to study partial-volume effects). Additionally, the technique was tested on three patients. The phantom experimental results (echo time 5 5.5 ms, h ≤ 218) agreed with theoretical predictions to within 10%. For the patient studies, the measured VOFs had reasonable amplitude and shape characteristics and the patients' superior sagittal sinus angles (<158) and curvatures (radii ≈ 40 mm) were within the range explored with phantoms. Our results suggest that partial-volume contributions to the VOF will be <5% and that the VOF can be evaluated in vivo to within 10% error. In conclusion, it is highly feasible to use MR signal phase to measure the VOF in the superior sagittal sinus for human dynamic contrast-enhanced MRI. Magn Reson Med 63:772-781,

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.

BACKGROUND AND PURPOSE:The prognostic value of dynamic contrast-enhanced MR imaging-derived plasma volume obtained in tumor and the contrast transfer coefficient has not been well-established in patients with gliomas. We determined whether plasma volume and contrast transfer coefficient in tumor correlated with survival in patients with gliomas in addition to other factors such as age, type of surgery, preoperative Karnofsky score, contrast enhancement, and histopathologic grade.

BACKGROUND AND PURPOSE:The accuracy of tumor plasma volume and K trans 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.

Dynamic contrast-enhanced (DCE) MRI is often used to measure the transfer constant (Ktrans) and distribution volume (ve) in pelvic tumors. For optimal accuracy and reproducibility, one must quantify the arterial input function (AIF). Unfortunately, this is challenging due to inflow and signal saturation. A potential solution is to use MR signal phase (ϕ), which is relatively unaffected by these factors. We hypothesized that phase-derived AIFs (AIFϕ) would provide more reproducible Ktrans and ve values than magnitude-derived AIFs (AIF|S|). We tested this in 27 prostate dynamic contrast-enhanced MRI studies (echo time = 2.56 ms, temporal resolution = 13.5 s), using muscle as a standard. AIFϕ peak amplitude varied much less as a function of measurement location (inferior–superior) than AIF|S| (5.6 ± 0.6 mM vs. 2.6 ± 1.5 mM), likely as a result of ϕ inflow insensitivity. However, our main hypothesis was not confirmed. The best AIF|S| provided similar reproducibility versus AIFϕ (interpatient muscle Ktrans = 0.039 ± 0.021 min−1 vs. 0.037 ± 0.025 min−1, ve = 0.090 ± 0.041 vs. 0.062 ± 0.022, respectively).