Convexity subarachnoid haemorrhage: reversible cerebral vasoconstriction syndrome

Case contributed by Prof Peter Mitchell


Headache, sudden onset. Confusion. Code stroke called.

Patient Data

Age: 51
Gender: Female

There is high attenuation material within the left precentral sulcus in keeping with a small volume of acute subarachnoid haemorrhage.

No remote intra- or extra-axial acute haemorrhages. No intracranial mass lesions. No acute or established cortical infarcts currently evident.

MRI brain

Small areas of abnormal T2/FLAIR signal are seen at the grey-white matter junction involving the right occipital lobe and both parietal lobes. These are bright on DWI but are not not unequivocally low on ADC.

High sulcal FLAIR signal in the left precentral gyrus correlates to be high density on CT, and is in keeping with acute subarachnoid blood.

No abnormal enhancement on the postcontrast images. No definite abnormality on suboptimal MRA-patient motion-subtle areas of narrowing in M2 and M3 left MCA branches. No MRI findings suspicious for posterior circulation dissection. The dural venous sinuses are patent on MRV.


There is only subtle MRA abnormality, but the parenchymal findings and convexity subarachnoid blood would be in keeping with RCVS if in the appropriate clinical and lab context. PRES or vasculitis can also have this appearance. Further evaluation with DSA would be helpful. No evidence of cerebral venous sinus thrombosis or cerebral aneurysm.


Study limited due to poor co-operation and shortness of breath.

Patchy irregularity noted involving the PCA branches bilaterally.

Irregularity also noted along the ACA 3rd and 4t degree branches on the left side.

No convincing evidence of an aneurysm identified. The remainder of the study given the limitations was unremarkable.


Consistent with RCVS. Close follow up and correlation with laboratory findings important to exclude vasculitis, or SAH secondary to other occult pathologies

Case Discussion

Thunderclap headache is a typical presentation, and may be associated with convexal SAH as in this case.  More commonly there is no SAH.  MRA may be of poor quality or targetted to the circle of Willis, and may miss the stenoses.  Angiography is typically positive in the distal branches - follow up imaging with 3T MRA +/- contrast typically shows complete resolution of vessel findings. Clinical and imaging findings distinguish this syndrome from PACNS and post aneurysmsal SAH related vsaospasm.

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Case information

rID: 34462
Case created: 22nd Feb 2015
Last edited: 21st Oct 2017
Tag: rcvs
Inclusion in quiz mode: Included

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