Assessment of vascular supply of hypervascular extra-axial brain tumors with 3T MR regional perfusion imaging

Abstract

Background and purpose: The vascular supply of extra-axial brain tumors provided by the external carotid artery has not been studied with RPI. The purpose of this work was to determine whether RPI assessment is feasible and provides information on the vascular supply of hypervascular extra-axial brain tumors.

Materials and methods: Conventional ASL and RPI studies were performed at 3T in 8 consecutive patients with meningioma. On the basis of MRA results, we performed RPI by placing a selective labeling slab over the external carotid artery. Five patients underwent DSA before surgery. Two neuroradiologists independently evaluated the overall image quality, the degree of tumor perfusion, and the extent of the tumor vascular territory on conventional ASL and RPI.

Results: In overall quality of conventional ASL and RPI, no images interfered with interpretation. In comparisons of the vascular tumor territory identified by the conventional ASL and RPI techniques, the territories coincided in 3 cases, were partially different in 4, and completely different in 1. The interobserver agreement was very good (kappa = 0.82). In 5 patients who underwent DSA, the 4 patients in whom the dominant supply was the external carotid artery were scored as coincided or partially different. The 1 patient in whom the vascular supply was from the internal carotid artery was scored as completely different.

Conclusions: RPI with selective labeling of the external carotid artery is feasible and may provide information about the vascular supply of hypervascular extra-axial brain tumors.

Fig 1.

On the basis of MR angiography results, we acquired regional perfusion images by placing a selective labeling slab over the external carotid artery.

Fig 2.

A 58-year-old man with malignant meningioma at the convexity (case 4). A and B, Anteroposterior (A) and lateral (B) projections of the right external carotid angiogram show a hypervascular region (arrows) fed by the right middle meningeal artery. C, Lateral projection of the right internal carotid angiogram shows a parasitic supply from the anterior cerebral artery branches (arrows). The tumor is also fed by the falx artery (arrowhead) from the ophthalmic artery. D, T2-weighted image demonstrates a large mass lesion at the right frontal convexity. E, Conventional ASL image shows a vascular territory with higher perfusion than that in the normal-appearing cortex (arrows). The degree of tumor perfusion is classified as grade 3. F, RPI acquired at the same level as E. The extent of the vascular tumor territory is slightly smaller on the RPI than on the conventional ASL image (arrows). The extent of tumor perfusion on the 2 techniques is classified as partially different.

Fig 3.

A 71-year-old woman with a meningioma at the right cavernous sinus (case 8). A, Anteroposterior projection of the right internal carotid angiogram shows dilated feeding arteries (arrow and arrowhead) from the internal carotid and ophthalmic arteries, respectively. The external carotid artery branches are also seen due to reflux of contrast medium. B, Lateral projection of the left internal carotid angiogram clearly shows dilated feeding arteries (arrows) from the internal carotid artery. C, Contrast-enhanced 3D TFE image demonstrates a well-enhanced mass lesion at the right cavernous sinus and posterior cranial fossa. D, Conventional ASL image shows a tumor vascular territory with higher perfusion than that in the normal-appearing cortex (arrow). The degree of tumor perfusion is classified as grade 3. E, RPI acquired at the same level as D. The hypervascular territory is not depicted on the RPI (arrow). The extent of tumor perfusion on the 2 techniques is classified as completely different.