Type:
Educational Exhibit
Keywords:
Ischaemia / Infarction, Diagnostic procedure, MR, CT-Angiography, CT, Neuroradiology brain
Authors:
E. Scapin1, A. Mereu1, M. V. V. Cherchi2, L. Saba3; 1Monserrato (CA)/IT, 2Selargius (CA)/IT, 3Cagliari/IT
DOI:
10.26044/ecr2019/C-1151
Findings and procedure details
The artery of Percheron,
first described in 1973 [4],
has a variable prevalence ranging between 4% and 12% in the general population according to Arauz et al [5].
PA occlusion causes bilateral paramedian thalamic stroke generally due to proximal embolism,
with asymmetric involvement in two-thirds of cases.
A predisposition to embolism due to patent foramen ovale might be a possibility.
Hypertension,
hyperlipidaemia and smoking are other common risk factors for stroke [6].
The clinical presentation is complex due to the presence of multiple nuclei and the reticular activating system.
It is typically characterized by a triad of altered mental status,
vertical gaze palsy and memory impairment [7,8,9].
Moreover signs may include miosis,
internuclear opthalmoplegia and loss of convergence.
Severe cognitive impairment,
amnesic syndrome and impairment of executive function tend to resolve progressively with time,
but in a few patients have been detected some months after acute presentation [10,11].
CT scan might be useful mainly to exclude hemorrhage and it can delay the correct diagnosis due it low sensitivity [12].
The most reliable imaging technique to aid the diagnosis of artery of Percheron occlusion (AOP) remains MRI [6].
It indeed allows visualization of the infarct with the “V-sign”: a pathologic hyperintense signal in fluid-attenuated inversion recovery (FLAIR) and diffusion weighted imaging (DWI) of both thalami,
with a sensitivity of 67% according to literature [2].
Although other bithalamic lesions can be seen on MRI,
differential diagnosis such as venous infarction,
infiltrative neoplasms and infectious diseases should not be confused with AOP,
mainly because they involve multiple regions without respecting specific arterial territory.