BACKGROUND AND PURPOSE Contrast extravasation in DSC-MRI potentiates inaccurate and imprecise estimates of glioma rCBV. We tested assertions that preload and postprocessing algorithms minimize this error by comparing Gd-rCBV using permutations of these 2 techniques with criterion standard rCBV using MION, an intravascular agent. MATERIALS AND METHODS We imaged 7 Fisher rats with 9L gliosarcomas, by using 3T gradient-echo DSC-MRI with MION (2.0 mg Fe/kg) and staged injection of Gd-diethylene triamine pentaacetic acid: a 0.1-mmol/kg bolus provided no preload (P−) data and served as preload (P+) for a subsequent 0.2-mmol/kg bolus. We computed MION-rCBV (steady-state ΔR2*, tumor versus normal brain) and Gd-rCBV ΔR2* [t] integration) without (C−) and with (C+) postprocessing correction, thereby testing 4 correction permutations: P−C−, P−C+, P+C−, and P+C+. We tested whether each permutation reduced bias and variance of the Gd/MION rCBV differences by using generalized estimating equations and Fmax statistics (P < .05 significant). RESULTS Gd-rCBV progressively better approximated MION-rCBV with increasing leakage correction. There was no statistically significant bias for the mean percentage deviation of Gd-rCBV from MION-rCBV for any correction permutation, but there was significantly reduced variance by using P+C− (22-fold), P−C+ (32-fold), and P+C+ (267-fold) compared with P−C−. P+C+ provided significant additional variance reduction compared with P+C− (12-fold) and P−C+ (8-fold). Linear regression of Gd-rCBV versus MION-rCBV revealed P+C+ to have the closest slope and intercept compared with the ideal, substantially better than P+C−. CONCLUSIONS Preload and postprocessing correction significantly reduced the variance of Gd-rCBV estimates, and bias reduction approached significance. Postprocessing correction provide significant benefit beyond preload alone.

BACKGROUND AND PURPOSE:Little is known about how commonly the internal jugular vein is compressed by extrinsic structures in the upper neck. The purpose of this paper was to identify the frequency and cause of external compression of the superior segment of the internal jugular vein.

BACKGROUND AND PURPOSE Both technical and pathophysiologic factors affect PSR in DSC-MR imaging. We aimed to determine how TE, flip angle (α), and contrast dose impact PSR in high-grade gliomas. MATERIALS AND METHODS We retrospectively computed PSR maps for 22 patients with high-grade gliomas, comparing 3 DSC-MR imaging methods by using single-dose gadodiamide without preload administration: A (n = 7), α = 35°, TE = 54 ms; B (n = 5), α = 72°, TE = 30 ms; C (n = 10), α = 90°, TE = 30 ms. Methods A–C served as preload for subsequent dynamic imaging using method D (method C parameters but with double-dose contrast). We compared first- and second-injection tumor PSR for methods C and D (paired t test) and tumor PSR for both injections grouped by the first-injection acquisition method (3-group nonparametric 1-way ANOVA). We compared PSR in tumor and normal brain for each first- and second-injection method group (paired t test). RESULTS First-injection PSR in tumor and normal brain differed significantly for methods B (P = .01) and C (P = .05), but not A (P = .71). First-injection tumor PSR increased with T1 weighting with a significant main effect of method groupings (P = .0012), but there was no significant main effect for first-injection normal brain (P = .93), or second-injection tumor (P = .95) or normal brain (P = .13). In patients scanned with methods C and D, first-injection PSR significantly exceeded second-injection PSR for tumor (P = .037) and normal brain (P < .001). CONCLUSIONS PSR strongly depends on the T1 weighting of DSC-MR imaging, including pulse sequence (TE, α) and contrast agent (dose, preload) parameters, with implications for protocol design and the interpretation and comparison of PSR values across tumor types and imaging centers.