Multiple cerebral aneurysm, case 2

This 66 year old female presented with progressive visual disturbance. Ophthalmological examination confirmed a left nasal sided visual field defect.
The initial CT examination was performed in order to rule out a left juxtasellar space occupying lesion. It revealed bilateral abnormalities of the supraclinoid segments of the internal carotid arteries. The subsequent combined MRI-MRA examination established the diagnosis of a left supraclinoid giant saccular aneurysm and suggested an associated aneurysmal lesion contralaterally in the same location. Before therapeutic decision making a conventional catheter based cerebral angiography was also performed.

Multiple cerebral aneurysms, 1.5 T
Fig.1 Transverse non-enhanced (above) and contrast-enhanced CT images. The marked contrast enhancement suggests vascular lesions in conjunction with the internal carotid arteries. Differential diagnosis includes: pituitary or suprasellar tumors.
Fig.2 Sagittal T1-weighted spin-echo images of the midline structures. The suprasellar lesions exhibit inhomogeneous signal intensities.
Fig.3 Transverse proton density (left) and T2-weighted (right) fast spin-echo images of the suprasellar region. The rounded inhomogeneous lesion in conjunction with the left internal carotid artery suggests a thrombosed saccular aneurysm. The irregular vascular image on the right could represent either dolichoectasia or a second, smaller aneurysm.
Fig.4 Transverse source images from a Gadolinium-enhanced 3D TOF acquisition data set. On analyzing the adjacent slices, the inflow channel (arrow) is identified. The center of the aneurysmal sac exhibits somewhat decreased signal intensity, (central stagnation with some spin saturation despite the intravenous contrast injection).
Fig.5 Transverse targeted MIP reconstructions from a multi-slab 3D TOF MRA acquisition data set. The left sided giant aneurysm is clearly seen, however doubt persists concerning the right carotid siphon (dolichoectasia versus aneurysm). Decreased intravascular signal intensity is seen in the left middle cerebral artery, due to spin saturation in the aneurysmal sac (similar phenomenon as in Giant internal carotid artery aneurysm: patient case 1 and Giant internal carotid artery aneurysm: patient case 2).
Fig.6 Coronal (left) and sagittal (right) targeted MIP reconstructions of the internal carotid artery siphons from a multi-slab 3D TOF MRA data set. Demonstration of a second ("en mirroir") aneurysm (arrow) on the right supraclinoid internal carotid artery.
Fig.7 Sagittal averaged modulus (right) and corresponding magnitude of complex differences (right) type source images from a 3D PC MRA acquisition. Intraaneurysmal flow appears to be essentially peripheral and circular with extremely slow flow in the center of the left giant internal carotid artery aneurysm.

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