Correlation of MR imaging-determined cerebral blood volume maps with histologic and angiographic determination of vascularity of gliomas.

Abstract

OBJECTIVE. Our purpose wasto evaluate therelationships betweentheratioof maxi mum relative cerebral blood volume (rCBV) (rCBV ratio = rCBV[tumor] I rCBV[contralat eral white matter]) and histologic and angiographic vascularities of gliomas using the gradient-echo echoplanar MR imaging technique. We also evaluated the usefulness of rCBV maps for grading gliomas. SUBJECTS AND METHODS. We examined 30 patients with histologically verifiedgliomas. Gliomas were classified as glioblastoma, anaplastic glioma with enhancement, ana plastic glioma without enhancement, and low-grade glioma. The maximum rCBV ratio of each glioma was compared with both histologic and angiographic vascularities, and the rela tionship between the maximum rCBV ratios and each type of glioma was established. RESULTS. The maximumrCBV ratiosof thegliomassignificantly correlated with both for low-gradegliomas.The maximumrCBV ratiosofthe glioblastomaswere significantlyhigher than those of the anaplastic gliomas without enhancement (p = .002) and the low-grade gliomas (p < .001). The maximum rCBV ratios of the anaplastic gliomas with enhancement were higher than those of the anaplastic gliomas without enhancement and the low-grade glio mas, but the differences were not statistically significant (p = .08 and p = .03, respectively). CONCLUSION. The resultsof perfusion-sensitive MR imagingwith gradient-echoechoplanar technique correlated with both histologic and angiographic vascularities. [6] reportedthat the degree of vascularity of gliomas observed with a spin echo echoplanar technique correlated well with histologic vascularity and that these re suIts might show the ability of the spin-echo echoplanar technique to detect neovasculariza tion at the capillary level. However, tumor an giogenesis is a complex process, and the existence of larger neovascular structures (such as feeding arteries and draining veins) associated with malignant tumors is not un common. A study documented that some tu mors have average capillary diameters two to three times those of normal tissues [7].The gradient-echo echoplanar technique produces hemodynamic maps by representing theeffectsoftotal bloodvolumefromcapillar ies to large vessels and weighs all vessels ape proximately equally [8]. In addition, this technique, because of its greater sensitivity to

Assessment of Angiographic Vascularity of Meningiomas with Dynamic Susceptibility Contrast-Enhanced Perfusion-Weighted Imaging and Diffusion Tensor Imaging

“…To our knowledge, such correlation has not been reported in meningiomas, though it was observed in gliomas. 26 The inverse correlation between FA and angiographic vascularity, as demonstrated in the present study, had allowed the use of FA to differentiate meningiomas of different angiographic vascularity, with diagnostic performance close to that of DSC-PWI. Therefore, DTI may serve as an alternative to DSC-PWI when administration of gadolinium-based contrast medium is a contraindication in patients who are subject to development of nephrogenic systemic fibrosis caused by low glomerular filtration rate.…”

Correlation between arterial blood volume obtained by arterial spin labelling and cerebral blood volume in intracranial tumours

“…Measurement of CBV by DSC-MRI has been shown to correlate with both conventional angiographic assessments of tumour vascular density and histological measurements of tumour neovascularization [5][6][7]. Parenthetically, it should be mentioned that increased tumour vascularity is not always synonymous with malignancy since especially extraaxial neoplasms, e.g.…”

“…Perfusion parameters can contribute to tumour grading, and DSC-MRI estimates have been shown to differ between high-grade and low-grade gliomas [5][6][7][8] and to be related to clinical outcome (survival time) [24]. Furthermore, ASL perfusion has consistently shown higher CBF values in high-grade than in low-grade gliomas [25][26][27].…”

“…The degree of tumour angiogenesis and capillary permeability can be assessed by bolus-tracking perfusion MRI measurements, for example, dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Several studies have shown a statistically strong correlation between tumour cerebral blood volume (CBV) and astrocytoma grading [5,6], as well as between tumour CBV and conventional angiographic tumour vascularity [7] with the exception of oligodendrogliomas that may display elevated tumour CBV not reflective of high grade histopathology [8].…”

Vaso-occlusive and prothrombotic mechanisms associated with tumor hypoxia, necrosis, and accelerated growth in glioblastoma

“…Such enhancement is due to the increased permeability of vessel walls to both intravenously injected contrast agents and to proteins that bind them, such as albumin. 57,58 As a result, contrast agents leak into tumoral but not normal brain tissue. Microscopically, there is increased fenestration of vessel walls, pericyte detachment, and alteration of the extracellular matrix.…”