The role of three-dimensional pseudo-continuous arterial spin labelling in grading and differentiating histological subgroups of meningiomas

Abstract

To evaluate the usefulness of pseudo-continuous arterial spin labelling (pCASL) imaging in grading and differentiating histological subtypes of meningiomas. In this prospective study, conventional magnetic resonance imaging (MRI) with contrast-enhanced T1-weighted images and pCASL were acquired with a 3 T MRI system before surgery in 125 consecutive patients with suspected meningiomas. Finally, the perfusion parameters were collected from 84 grade I and 23 grade II meningiomas. On the pCASL perfusion map, the mean absolute cerebral blood flow (CBF) values from the meningioma (CBFtumour), peritumoural oedema (CBFPTO), white matter of contralateral centrum semi-ovale (CBFwm) and normal grey matter (CBFgm) were calculated. Additionally, the associations of these perfusion parameters with the value of ki-67 index were analysed. The CBFwm value correlated negatively with the largest diameter of the tumour, which limited its usage as a reference for ratio calculation. The CBFtumour values of grade II and grade I meningiomas did not differ significantly: 137.36±71.85 ml/min/100 g versus 123.58±135.80 ml/min/100 g (p=0.641). The CBFPTO value was higher for grade II meningioma as than for grade I meningiomas: 30.30±15.56 ml/min/100 g versus 22.33±9.87 ml/min/100 g (p=0.037). The CBFtumour value was highest in angiomatous meningioma and lowest in fibrous meningioma, thus enabling the differentiation of subtypes of meningioma. The CBFtumour value did not correlate with the ki-67 index of meningioma. The CBFPTO value, rather than the CBFtumour value, from pCASL imaging may serve as a key factor in distinguishing different grades of meningiomas. Moreover, angiomatous meningiomas and fibrous meningiomas can be identified by CBFtumour value.