Subarachnoid hemosiderosis and superficial cortical hemosiderosis in cerebral amyloid angiopathy

Abstract

Cerebral amyloid angiopathy (CAA) is an important cause of intracerebral hemorrhage. Its definite diagnosis still requires histopathologic demonstration of vascular amyloid. Thus, further improvement of noninvasive imaging methods would be desirable. Here we present 3 patients with histologically proved CAA, in which superficial cortical hemosiderosis and subarachnoid hemosiderosis were present in T2*-weighted MR images. Thus, we propose that these 2 findings might be valuable as noninvasive diagnostic markers for CAA.

Fig 1.

Patient 1, a 70-year-old woman with global aphasia and severe apraxia. T2*-weighted image demonstrates superficial cortical hemosiderosis in the left parietal cortex (arrows).

Fig 2.

Patient 2, a 69-year-old man with severe headache, visual disturbances, and nausea. A,B, T2*-weighted images depict left frontal subarachnoid hemosiderosis (dotted arrows) and left parietal superficial cortical hemosiderosis (arrows).

Fig 3.

Patient 3, a 72-year-old woman with histopathologically proved CAA and a large hyperacute right frontal intracerebral macrohemorrhage (thick arrows). A,B, T2*-weighted images demonstrate the hyperacute lobar hemorrhage (thick arrows), subarachnoid hemosiderosis (dotted lines), and superficial cortical hemosiderosis (thin arrows).

Fig 4.

A–F, Schematic drawings illustrating subarachnoid hemosiderosis and superficial cortical hemosiderosis. A–D, Coronal schematic drawings, illustrating the time-dependent development of subarachnoid hemosiderosis and superficial cortical hemosiderosis (black, subarachnoid space; white line, pia mater; orange line, arachnoid layer; light blue, dura mater). E,F, Horizontal schematic drawings corresponding to the areas marked with black bars in B and C, demonstrating the visual appearance of subarachnoid hemosiderosis and superficial cortical hemosiderosis on axial sections. A, Normal appearance of the subarachnoid space. B,E, Subarachnoid hemorrhage (red) presenting as a linear signal intensity in the subarachnoid space (E). C, Residues of blood penetrating the pia mater and deposit in the superficial layers of the cerebral cortex. D,F, Superficial cortical hemosiderosis, defined as linear residues of blood in the superficial layers of the cerebral cortex (dark red). Superficial cortical hemosiderosis typically has a bilinear “tracklike” appearance on axial sections, caused by the signal intensity of the normal-appearing subarachnoid space in the middle, which is bordered bilaterally by linear deposits of hemosiderin in the superficial layers of the adjacent cortex (F).