Contribution of perfusion-weighted magnetic resonance imaging in the differentiation of meningiomas and other extra-axial tumors: case reports and literature review

Abstract

We present six cases of extra-axial lesions: three meningiomas [including one intraventricular and one cerebellopontine angle (CPA) meningioma], one dural metastasis, one CPA schwannoma and one choroid plexus papilloma which were chosen from a larger cohort of extra-axial tumors evaluated in our institution. Apart from conventional MR examinations, all the patients also underwent perfusion-weighted imaging (PWI) using dynamic susceptibility contrast method on a 1.5 T MR unit (contrast: 0.3 mmol/kg, rate 5 ml/s). Though the presented tumors showed very similar appearance on conventional MR images, they differed significantly in perfusion examinations. The article draws special attention to the usefulness of PWI in the differentiation of various extra-axial tumors and its contribution in reaching final correct diagnoses. Finding a dural lesion with low perfusion parameters strongly argues against the diagnosis of meningioma and should raise a suspicion of a dural metastasis. In cases of CPA tumors, a lesion with low relative cerebral blood volume values should be suspected to be schwannoma, allowing exclusion of meningioma to be made. In intraventricular tumors arising from choroid plexus, low perfusion parameters can exclude a diagnosis of meningioma. In our opinion, PWI as an easy and quick to perform functional technique should be incorporated into the MR protocol of all intracranial tumors including extra-axial neoplasms.

Fig. 1

Two dural lesions: T1 post-contrast (a, d) images, CBV maps (b, e) and time-intensity curves (c, f). a–c Parafalcine meningioma with high rCBV values (red coloring) on perfusion maps and the typical time-intensity curve with no return to the baseline after high signal drop (violet curve). d–f Dural metastasis mimicking meningioma on conventional MR images but with low rCBV values (blue coloring) and the time-intensity curve returning to the baseline (violet curve)

Fig. 2

Two CPA tumors: T1 post-contrast (a, d) images, CBV maps (b, e) and time-intensity curves (c, f). a–c Typical schwannoma with low perfusion parameters (blue coloring) and the time-intensity curve returning to the baseline (violet curve). d–f Meningioma with intracanalicular enhancing part showing typical hyperperfusion (red coloring) and the time-intensity curve with no return to the baseline (violet curve)

Fig. 3

Two intraventricular tumors: T1 post-contrast (a, d) images, CBV maps (b, e) and time-intensity curves (c, f). a–c choroid plexus papilloma with low rCBV values on perfusion maps (blue and green coloring) and the time-intensity curves showing no return to the baseline (violet curves). d–f intraventricular meningioma with typical high rCBV values (red coloring) and the time-intensity curve with no return to the baseline (violet curve)