Dynamic Susceptibility-weighted Contrast-enhanced Perfusion MR Research Articles

Outcome of radiosurgery for recurrent malignant gliomas: assessment of treatment response using relative cerebral blood volume.

Gamma knife radiosurgery (GKS) is efficacious for treating recurrent malignant gliomas as a salvage treatment. However, contrast enhancement alone on MR imaging remains difficult to determine the treatment response following GKS. The purpose of this study was to evaluate the radiosurgical effect for recurrent malignant gliomas and to clarify if relative cerebral blood volume (rCBV) derived from dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR imaging could represent the treatment response. Between March 2006 and December 2008, 38 patients underwent GKS for recurrent malignant gliomas. Before and after GKS, DSC perfusion MR imaging datasets were retrospectively reprocessed and regions of interest were drawn around the contrast-enhancing region targeted with GKS. DSC-perfusion MR scans were assessed at a regular interval of two months. Following GKS for the recurrent lesions, MR images showed response (stable disease or partial response) in 26 of 38 patients (68.4 %) at post-GKS 2 months and 18 of 38 patients (47.3 %) at post-GKS 4 months. Initial mean rCBV value was 2.552 (0.586-6.178) at the pre-GKS MRI. In the response group, mean rCBV value was significantly decreased (P < 0.05) at the follow up of 2 and 4 months. However, in the treatment-failure group, mean rCBV value had no significant change. We suggest that GKS is an alternative treatment choice for the recurrent glioma. DSC-perfusion MR images are helpful to predict the treatment response after GKS.

Differentiation of Primary Central Nervous System Lymphomas from High-Grade Gliomas by rCBV and Percentage of Signal Intensity Recovery Derived from Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging

Primary central nervous system lymphoma (PCNSL) and high-grade glioma (HGG) may have similar enhancement patterns on magnetic resonance imaging (MRI), making the differential diagnosis difficult or even impractical. Relative cerebral blood volume (rCBV) and percentage of signal intensity recovery derived from dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR imaging may help distinguish PCNSL from HGG. The purpose of this study was to evaluate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of these two imaging parameters used alone or in combination for differentiating PCNSL from HGG. A total of 12 patients with PCNSL and 26 patients with HGG were examined using a 3T scanner. rCBV and percentage of signal intensity recovery were obtained and receiver operating characteristic (ROC) analysis was performed to determine optimum thresholds for tumor differentiation. Sensitivity, specificity, PPV, NPV, and accuracy for identifying the tumor types were also calculated. The optimum threshold of 2.56 for rCBV provided sensitivity, specificity, PPV, NPV, and accuracy of 96.2, 90, 92.6, 94.7, and 93.5%, respectively, for determining PCNSL. A threshold value of 0.89 for percentage of signal intensity recovery optimized differentiation of PCNSL and HGG with a sensitivity, specificity, PPV, NPV, and accuracy of 100, 88.5, 87, 100, and 93.5%, respectively. Combining rCBV with the percentage of signal intensity recovery further improved the differentiation of PCNSL and HGG with a specificity of 98.5% and an accuracy of 95.7%. The combination of rCBV measurement with percentage of signal intensity recovery can help in more accurate differentiation of PCNSL from HGG.

Correlation between Cerebral Blood Volume Measurements by Perfusion-Weighted Magnetic Resonance Imaging and Two-Year Progression-Free Survival in Gliomas

Our goal was to determine whether relative cerebral blood volume (rCBV) can serve as an adjunct to histopathologic grading in the assessment of gliomas, with the hypothesis that rCBV can predict two-year survival. We evaluated 29 newly diagnosed gliomas (13 WHO grade II, seven grade III, nine grade IV; 17 astrocytomas, 12 oligodendroglial tumors). Dynamic susceptibility-weighted contrast-enhanced perfusion MR images and CBV maps were obtained. rCBVmax measurements (maximum tumor CBV/contralateral normal tissue CBV) and progression-free survival (PFS) were recorded. Receiver operating characteristic curves and Kaplan-Meier survival curves were calculated for rCBVmax and histologic grade. rCBVmax measurements differed between gliomas without (2.38 +/- 1.22) and with progression (5.57 +/- 2.84) over two years. The optimal rCBVmax cut-off value to predict progression was 2.95. rCBVmax < 2.95 was a significant predictor of two-year PFS, almost as accurate as WHO grade II. In the pure astrocytoma subgroup, the optimal rCBVmax cut-off value to predict progression was 2.85. In this group rCBVmax < 2.85 was a significant predictor of two-year PFS, an even better predictor of two-year PFS than WHO grade II. rCBVmax can be used to predict two-year PFS in patients with gliomas, independent of pathologic findings, especially in tumors without oligodendroglial components.

Server A, Orheim TED, Graff BA et al. Diagnostic examination performance by using microvascular leakage, cerebral blodd volume, and blood flow derived from 3-T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in the differentiation of glioblastoma multiforme and brain metastasis. Neuroradiology 2011; 53: 319–330

Server A, Orheim TED, Graff BA et al. Diagnostic examination performance by using microvascular leakage, cerebral blodd volume, and blood flow derived from 3-T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in the differentiation of glioblastoma multiforme and brain metastasis. Neuroradiology 2011; 53: 319–330

Measurements of diagnostic examination performance and correlation analysis using microvascular leakage, cerebral blood volume, and blood flow derived from 3T dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging in glial tumor grading

To assess the diagnostic accuracy of microvascular leakage (MVL), cerebral blood volume (CBV) and blood flow (CBF) values derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC-MR imaging) for grading of cerebral glial tumors, and to estimate the correlation between vascular permeability/perfusion parameters and tumor grades. A prospective study of 79 patients with cerebral glial tumors underwent DSC-MR imaging. Normalized relative CBV (rCBV) and relative CBF (rCBF) from tumoral (rCBVt and rCBFt), peri-enhancing region (rCBVe and rCBFe), and the value in the tumor divided by the value in the peri-enhancing region (rCBVt/e and rCBFt/e), as well as MVL, expressed as the leakage coefficient K(2) were calculated. Hemodynamic variables and tumor grades were analyzed statistically and with Pearson correlations. Receiver operating characteristic (ROC) curve analyses were also performed for each of the variables. The differences in rCBVt and the maximum MVL (MVL(max)) values were statistically significant among all tumor grades. Correlation analysis using Pearson was as follows: rCBVt and tumor grade, r = 0.774; rCBFt and tumor grade, r = 0.417; MVL(max) and tumor grade, r = 0.559; MVL(max) and rCBVt, r = 0.440; MVL(max) and rCBFt, r = 0.192; and rCBVt and rCBFt, r = 0.605. According to ROC analyses for distinguishing tumor grade, rCBVt showed the largest areas under ROC curve (AUC), except for grade III from IV. Both rCBVt and MVL(max) showed good discriminative power in distinguishing all tumor grades. rCBVt correlated strongly with tumor grade; the correlation between MVL(max) and tumor grade was moderate.

Differentiation of Recurrent Glioblastoma Multiforme from Radiation Necrosis after External Beam Radiation Therapy with Dynamic Susceptibility-weighted Contrast-enhanced Perfusion MR Imaging

Differentiation of Recurrent Glioblastoma Multiforme from Radiation Necrosis after External Beam Radiation Therapy with Dynamic Susceptibility-weighted Contrast-enhanced Perfusion MR Imaging

Optimized Preload Leakage-Correction Methods to Improve the Diagnostic Accuracy of Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging in Posttreatment Gliomas

Relative cerebral blood volume (rCBV) accuracy can vary substantially depending on the dynamic susceptibility-weighted contrast-enhanced (DSC) acquisition and postprocessing methods, due to blood-brain barrier disruption and resulting T1-weighted leakage and T2- and/or T2*-weighted imaging (T2/T2*WI) residual effects. We set out to determine optimal DSC conditions that address these errors and maximize rCBV accuracy in differentiating posttreatment radiation effect (PTRE) and tumor. We recruited patients with previously treated high-grade gliomas undergoing image-guided re-resection of recurrent contrast-enhancing MR imaging lesions. Thirty-six surgical tissue samples were collected from 11 subjects. Preoperative 3T DSC used 6 sequential evenly timed acquisitions, each by using a 0.05-mmol/kg gadodiamide bolus. Preload dosing (PLD) and baseline subtraction (BLS) techniques corrected T1-weighted leakage and T2/T2*WI residual effects, respectively. PLD amount and incubation time increased with each sequential acquisition. Corresponding tissue specimen stereotactic locations were coregistered to DSC to measure localized rCBV under varying PLD amounts, incubation times, and the presence of BLS. rCBV thresholds were determined to maximize test accuracy (average of sensitivity and specificity) in distinguishing tumor (n = 21) and PTRE (n = 15) samples under the varying conditions. Receiver operator characteristic (ROC) areas under the curve (AUCs) were statistically compared. The protocol that combined PLD (0.1-mmol/kg amount, 6-minute incubation time) and BLS correction methods maximized test AUC (0.99) and accuracy (95.2%) compared with uncorrected rCBV AUC (0.85) and accuracy (81.0%) measured without PLD and BLS (P = .01). Combining PLD and BLS correction methods for T1-weighted and T2/T2*WI errors, respectively, enables highly accurate differentiation of PTRE and tumor growth.

Relative Cerebral Blood Volume Values to Differentiate High-Grade Glioma Recurrence from Posttreatment Radiation Effect: Direct Correlation between Image-Guided Tissue Histopathology and Localized Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging Measurements

Differentiating tumor growth from posttreatment radiation effect (PTRE) remains a common problem in neuro-oncology practice. To our knowledge, useful threshold relative cerebral blood volume (rCBV) values that accurately distinguish the 2 entities do not exist. Our prospective study uses image-guided neuronavigation during surgical resection of MR imaging lesions to correlate directly specimen histopathology with localized dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC) measurements and to establish accurate rCBV threshold values, which differentiate PTRE from tumor recurrence. Preoperative 3T gradient-echo DSC and contrast-enhanced stereotactic T1-weighted images were obtained in patients with high-grade glioma (HGG) previously treated with multimodality therapy. Intraoperative neuronavigation documented the stereotactic location of multiple tissue specimens taken randomly from the periphery of enhancing MR imaging lesions. Coregistration of DSC and stereotactic images enabled calculation of localized rCBV within the previously recorded specimen locations. All tissue specimens were histopathologically categorized as tumor or PTRE and were correlated with corresponding rCBV values. All rCBV values were T1-weighted leakage-corrected with preload contrast-bolus administration and T2/T2*-weighted leakage-corrected with baseline subtraction integration. Forty tissue specimens were collected from 13 subjects. The PTRE group (n = 16) rCBV values ranged from 0.21 to 0.71, tumor (n = 24) values ranged from 0.55 to 4.64, and 8.3% of tumor rCBV values fell within the PTRE group range. A threshold value of 0.71 optimized differentiation of the histopathologic groups with a sensitivity of 91.7% and a specificity of 100%. rCBV measurements obtained by using DSC and the protocol we have described can differentiate HGG recurrence from PTRE with a high degree of accuracy.

Distinguishing Recurrent Intra-Axial Metastatic Tumor from Radiation Necrosis Following Gamma Knife Radiosurgery Using Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging

MR image-guided gamma knife radiosurgery is often used to treat intra-axial metastatic neoplasms. Following treatment, it is often difficult to determine whether a progressively enhancing lesion is due to metastatic tumor recurrence or radiation necrosis. The purpose of our study was to determine whether relative cerebral blood volume (rCBV), relative peak height (rPH), and percentage of signal-intensity recovery (PSR) derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging can distinguish recurrent metastatic tumor from radiation necrosis. Twenty-seven patients with systemic cancer underwent gamma knife radiosurgery for metastatic lesions of the brain and subsequently developed enlarging regions of enhancement within the radiation field. Subsequent surgical resection or clinicoradiologic follow-up established a diagnosis of recurrent metastatic tumor or radiation necrosis. Perfusion MR imaging datasets were retrospectively reprocessed, and regions of interest were drawn around the entire contrast-enhancing region. The resulting T2* signal-intensity time curves produced rCBV, rPH, and PSR values for each examination. A Welch t test was used to compare imaging values between groups. The mean, minimum, and maximum PSR values were significantly lower (P < .01) in cases of recurrent metastatic tumor. The mean and maximum rCBV and rPH values were significantly higher (P < .02) in the recurrent metastatic tumor group. The findings of our study suggest that perfusion MR imaging may be used to differentiate recurrent intra-axial metastatic tumor from gamma knife-induced radiation necrosis.

Perfusion MR Imaging: Moving Forward

HomeRadiologyVol. 249, No. 2 PreviousNext Reviews and CommentaryEditorialsPerfusion MR Imaging: Moving ForwardA. Gregory SorensenA. Gregory SorensenAuthor Affiliations1From the Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 13th Street, Bldg 149, MC 2301, Boston, MA 02129. Received August 11, 2008; final version accepted August 13.Address correspondence to the author (e-mail: [email protected]).A. Gregory SorensenPublished Online:Nov 1 2008https://doi.org/10.1148/radiol.2492081429MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References1 Villringer A, Rosen BR, Belliveau JW, et al. Dynamic imaging with lanthanide chelates in normal brain: contrast due to magnetic susceptibility effects. Magn Reson Med 1988;6:164–174. Crossref, Medline, Google Scholar2 Sorensen AG, Buonanno FS, Gonzalez RG, et al. Hyperacute stroke: evaluation with combined multisection diffusion-weighted and hemodynamically weighted echo-planar MR imaging. Radiology 1996;199:391–401. Link, Google Scholar3 Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists. Stroke 2007;38:1655–1711. Crossref, Medline, Google Scholar4 Wintermark M, Albers GW, Alexandrov AV, et al. Acute stroke imaging research roadmap. Stroke 2008;39:1621–1628. Crossref, Medline, Google Scholar5 Paulson ES, Schmainda KM. Comparison of dynamic susceptibility-weighted contrast-enhanced MR methods: recommendations for measuring relative cerebral blood volume in brain tumors. Radiology 2008;249:601–613. Google Scholar6 Boxerman J, Schmainda KM, Weisskoff RM. Relative cerebral blood volume maps corrected for contrast agent extravasation significantly correlate with glioma tumor grade whereas uncorrected maps do not. AJNR Am J Neuroradiol 2006;27:859–867. Medline, Google Scholar7 Cao Y, Tsien CI, Nagesh V, et al. Survival prediction in high-grade gliomas by MRI perfusion before and during early stage of RT [corrected]. Int J Radiat Oncol Biol Phys 2006;64:876–885. Crossref, Medline, Google Scholar8 Law M, Young RJ, Babb JS, et al. Gliomas: predicting time to progression or survival with cerebral blood volume measurements at dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging. Radiology 2008;247:490–498. Link, Google Scholar9 Schmainda KM, Rand SD, Joseph AM, et al. Characterization of a first-pass gradient-echo spin-echo method to predict brain tumor grade and angiogenesis. AJNR Am J Neuroradiol 2004;25:1524–1532. Medline, Google Scholar10 Batchelor TT, Sorensen AG, di Tomaso E, et al. AZD2171, a pan-VEGF receptor tyrosine kinase inhibitor, normalizes tumor vasculature and alleviates edema in glioblastoma patients. Cancer Cell 2007;11:83–95. Crossref, Medline, Google Scholar11 Hollingworth W, Medina LS, Lenkinski RE, et al. A systematic literature review of magnetic resonance spectroscopy for the characterization of brain tumors. AJNR Am J Neuroradiol 2006;27:1404–1411. Medline, Google ScholarArticle HistoryPublished in print: 2008 FiguresReferencesRelatedDetailsCited ByEuropean Journal of Radiology Open, Vol. 8Journal of Neuroimaging, Vol. 30, No. 2Der Radiologe, Vol. 56, No. 2Magnetic Resonance in Medical Sciences, Vol. 15, No. 2A Generic Support Vector Machine Model for Preoperative Glioma Survival AssociationsKyrre E. Emblem, Marco C. Pinho, Frank G. Zöllner, Paulina Due-Tonnessen, John K. Hald, Lothar R. Schad, Torstein R. Meling, Otto Rapalino, Atle Bjornerud, 8 December 2014 | Radiology, Vol. 275, No. 1Journal of Magnetic Resonance Imaging, Vol. 41, No. 2The Neuroradiology Journal, Vol. 28, No. 6Journal of Magnetic Resonance Imaging, Vol. 40, No. 1Neuro-Oncology, Vol. 16, No. suppl 7Pseudoprogression of Glioblastoma after Chemo- and Radiation Therapy: Diagnosis by Using Dynamic Susceptibility-weighted Contrast-enhanced Perfusion MR Imaging with Ferumoxytol versus Gadoteridol and Correlation with SurvivalSeymur Gahramanov, , Leslie L. Muldoon, , Csanad G. Varallyay, , Xin Li, , Dale F. Kraemer, , Rongwei Fu, , Bronwyn E. Hamilton, , William D. Rooney, , and Edward A. Neuwelt, 1 March 2013 | Radiology, Vol. 266, No. 3NMR in Biomedicine, Vol. 26, No. 8Neuroradiology, Vol. 55, No. 3Journal of Digital Imaging, Vol. 26, No. 2American Journal of Roentgenology, Vol. 200, No. 1American Journal of Neuroradiology, Vol. 33, No. 1International Journal of Radiation Oncology*Biology*Physics, Vol. 79, No. 2The Lancet Neurology, Vol. 9, No. 9American Journal of Neuroradiology, Vol. 31, No. 1Recommended Articles Imaging-based Selection for Endovascular Treatment in StrokeRadioGraphics2019Volume: 39Issue: 6pp. 1696-1713Whole-Brain CT Perfusion to Quantify Acute Ischemic Penumbra and CoreRadiology2016Volume: 279Issue: 3pp. 876-887Attenuation Changes in ASPECTS Regions: A Surrogate for CT Perfusion–based Ischemic Core in Acute Ischemic StrokeRadiology2019Volume: 291Issue: 2pp. 451-458Imaging of Heart Disease in WomenRadiology2016Volume: 282Issue: 1pp. 34-53Imaging Human Brain Perfusion with Inhaled Hyperpolarized 129Xe MR ImagingRadiology2017Volume: 286Issue: 2pp. 659-665See More RSNA Education Exhibits Brain CT Perfusion Studies: Turning False Ischaemic Penumbra into LightDigital Posters2019Stroke CT Perfusion Imaging: A Review of Quantitative and Qualitative ModalitiesDigital Posters2018Acute Ischemic Stroke: Time is Life — An Approach for No MistakesDigital Posters2019 RSNA Case Collection Acute ischemic strokeRSNA Case Collection2020Hypoxic ischemic encepholopathyRSNA Case Collection2020Herpes simplex encephalitisRSNA Case Collection2020 Vol. 249, No. 2 Metrics Altmetric Score PDF download

Differentiation of Glioblastoma Multiforme and Single Brain Metastasis by Peak Height and Percentage of Signal Intensity Recovery Derived from Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging

Glioblastoma multiforme (GBM) and single brain metastasis (MET) are the 2 most common malignant brain tumors that can appear similar on anatomic imaging but require vastly different treatment strategy. The purpose of our study was to determine whether the peak height and the percentage of signal intensity recovery derived from dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR imaging could differentiate GBM and MET. Forty-three patients with histopathologic diagnosis of GBM (n=27) or MET (n=16) underwent DSC perfusion MR imaging in addition to anatomic MR imaging before surgery. Regions of interest were drawn around the nonenhancing peritumoral T2 lesion (PTL) and the contrast-enhancing lesion (CEL). T2* signal intensity-time curves acquired during the first pass of gadolinium contrast material were converted to the changes in relaxation rate to yield T2* relaxivity (Delta R2*) curve. The peak height of maximal signal intensity drop and the percentage of signal intensity recovery at the end of first pass were measured for each voxel in the PTL and CEL regions of the tumor. The average peak height for the PTL was significantly higher (P=.04) in GBM than in MET. The average percentage of signal intensity recovery was significantly reduced in PTL (78.4% versus 82.8%; P=.02) and in CEL (62.5% versus 80.9%, P<.01) regions of MET compared with those regions in the GBM group. The findings of our study show that the peak height and the percentage of signal intensity recovery derived from the Delta R2* curve of DSC perfusion MR imaging can differentiate GBM and MET.

Comparison of first-pass and second-bolus dynamic susceptibility perfusion MRI in brain tumors

Our goal was to evaluate whether the T1 shortening effect caused by contrast leakage into brain tumors, a well-known confounding effect in the quantification of relative cerebral blood volume (rCBV) measurements, may be corrected by the administration of a predose of gadolinium-DTPA. As part of their presurgical imaging protocol, 25 patients with primary brain tumors underwent two consecutive dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR studies. Intratumoral rCBV measurements and normalized rCBV values obtained during the first-pass and second-bolus studies were compared (Wilcoxon signed-ranks test). The frequency of relatively increased rCBV ratios on the second-bolus study was compared between enhancing and non-enhancing neoplasms (Fisher's exact test). Postprocessing perfusion studies were evaluated for image quality on a scale of 0-3 (Wilcoxon signed-ranks test). Four studies were excluded due to unacceptable image quality. Mean normalized rCBVs were 9.04 (SD 4.64) for the first-pass and 7.99 (SD 3.84) for the second-bolus study. There was no statistically significant difference between the two perfusion studies in either intratumoral rCBV (P=0.237) or rCBV ratio (P=0.181). Five enhancing and four non-enhancing tumors showed a relative increase in rCBV ratio on the second-bolus study, without a significant difference between the groups. Image quality was not significantly different between perfusion studies. Our results did not demonstrate a significant difference between first-pass and second-bolus rCBV measurements in DSC perfusion MR imaging. The administration of a predose of gadolinium-DTPA does not appear to be an efficient way of compensating for the underestimation of intratumoral rCBV values due to the T1 shortening effect.

The optimal use of contrast agents at high field MRI

The intravenous administration of a standard dose of conventional gadolinium-based contrast agents produces higher contrast between the tumor and normal brain at 3.0 Tesla (T) than at 1.5 T, which allows reducing the dose to half of the standard one to produce similar contrast at 3.0 T compared to 1.5 T. The assessment of cumulative triple-dose 3.0 T images obtained the best results in the detection of brain metastases compared to other sequences. The contrast agent dose for dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging at 3.0 T can be reduced to 0.1 mmol compared to 0.2 mmol at 1.5 T due to the increased susceptibility effects at higher magnetic field strengths. Contrast agent application makes susceptibility-weighted imaging (SWI) at 3.0 T clinically attractive, with an increase in spatial resolution within the same scan time. Whereas a double dose of conventional gadolinium-based contrast agents was optimal in SWI with respect to sensitivity and image quality, a standard dose of gadobenate dimeglumine, which has a two-fold higher T1-relaxivity in blood, produced the same effect. For MR-arthrography, optimized concentrations of gadolinium-based contrast agents are similar at 3.0 and 1.5 T. In summary, high field MRI requires the optimization of the contrast agent dose in different clinical applications.

Low-Grade Gliomas: Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging—Prediction of Patient Clinical Response

Low-Grade Gliomas: Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging—Prediction of Patient Clinical Response