What is the Connection between Ivy and the Brain? – MRI-pattern can Guide the Way to Diagnosis

Introduction: Moyamoya is a chronic cerebrovascular disease characterized by progressive stenosis of the cerebrovascular arteries. The angiographically "cloudy" appearance of the vascular collaterals in the brain base area gives the disease its name. The "ivy sign" is the less known MRI pattern of the disease. Leptomeningeal collaterals in T1 post-KM and FLAIR sequences present themselves as diffuse signal enhancement at the brain surface (it appears like “ivy creeping on stone").

Materials and Methods: We report 3 patients with Moyamoya-disease who presented the “ivy-sign” in early MRI.

Case-Reports: Case 1: A boy with Noonan syndrome, at 5 years first focal epileptic seizures, no further neurological abnormalities. The MRI showed contrast-enhanced meninges. This was suspected as astrocytoma of the meninges and has led to close MRI-follow-ups. The findings in the follow-ups were stable. With 9 years an MRI-angiography was performed because of the increased risk in Noonan syndrome to develop Moyamoya. The segments M1 and M2 of the A. cerebri media were bilaterally occluded and collaterals were formed around the basal ganglia. 7 MRIs were undertaken before the diagnosis Moyamoya was made. Case 2: A girl was reported with recurrent cephalgias from 3 years onwards. During a severe infection at the age of 4 she had three seizures, so a MRI was performed. In this case the recognized contrast enhancement of the meninges was interpreted as meningeal irritation caused by infection. After further focal seizures a control-MRI with MR-angiography was performed. This showed bilateral occlusion of the A. cerebri media and a collateral network: Moyamoya-disaese was diagnosed in the consequence of the second neuroimaging. Case 3: A girl presented with head-ache since the age of 7 and intermittent paresthesia of hand and feet. MRI was performed with an additional MR-angiography. Due to occlusion of A. cerebri media M1 segment, collaterals at the base of the brain and furthermore leptomeningeal collaterals presenting as “ivy-sign” Moyamoya was diagnosed as result of the first neuroimaging.

Discussion: Recognizing the “ivy-sign” can shorten the way to diagnose Moyamoya-disease. In retrospect all three patients diagnosed with Moyamoya-disease showed the “ivy-sign” even in the first MRI. In case 1 and 2 other considerations were made: case 1 an astrocytoma of the meninges, case 2 meningeal irritation in context of the infection. In case 3 the additional MR-angiography led direct to the diagnosis.

Conclusion: To raise awareness of the “ivy sign” as MRI-pattern, we present three patients with Moyamoya-disease. The “ivy-sign” is not specific for Moyamoya. Other differential diagnosis must be considered. However, if this MRI pattern is found in the clarification of neurological disorders, Moyamoya should be considered and further diagnostics should be initiated.

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