WSO December 2023 – Issue 3 - 1154

1154
International Journal of Stroke 18(10)
Figure 1. Typical imaging findings. (a) Brain MRI (FLAIR
sequence) shows bilateral parieto-occipital vasogenic edema
and sulcal " dots " (white arrows) suggesting dilated cortical
surface arteries. Sausage-on-a-string appearance on (b) head
CT angiogram and (c) transfemoral cerebral angiogram. (d)
Follow-up head CT angiogram after 3 months shows reversal
of vascular abnormalities.
Figure 2. Brain MRI lesion patterns. (a) No acute
parenchymal lesion (24%). The hyperintense dot sign is
present on FLAIR (far right, arrow). (b) Border zone/
watershed infarcts (25%). (c) Vasogenic edema (28%). (d)
Hemorrhagic lesions (42%). (e) Lesion combinations (28%).
Source: Reprinted with permission from Neurology 2010;75(21):1939-41.
abnormal is characteristic of RCVS, and virtually rules out
underlying aneurysms and vascular malformations.
Hemorrhagic lesions occur early, perhaps from arterial rupture
or reperfusion injury,23,50 and ischemic strokes occur
later, from progressive vasoconstriction.16,20,24
RCVS is the most frequent cause of cSAH in individuals
< 60 years.60 In patients with cSAH, the presence of
TCH, FLAIR " dot sign, " and multifocal segmental vasoconstriction
are diagnostic of RCVS. Yet, many such
patients are subjected to conventional angiography to
exclude ruptured aneurysms and vascular malformations.
One study comparing RCVS-SAH to other types of SAH
showed that younger age, prior headache disorder, chronic
obstructive pulmonary disease, depression, antidepressant
medication, lower Hunt-Hess score, lower Fisher grade,
greater number of affected arteries, and bilateral arterial
involvement, were independent predictors of
RCVS-SAH.61
In RCVS, the location of ischemic lesions in arterial
" watershed " territories is distinctive (see Figure 2). Lobar
hemorrhages also occur in watershed regions, implicating
ischemia-reperfusion injury from dynamic vasoconstriction-vasodilation.
Reversible brain edema, in a PRES-like
pattern, develops in one-third.37 The earliest ischemic or
edematous lesions are usually located in cortical-subcortical
junctions.
International Journal of Stroke, 18(10)
Source: Reprinted with permission from Ann Neurol 2016;79:882-894.
The angiographic appearance of RCVS is distinct from
pathological entities such as atherosclerosis, vasculitis, and
fibromuscular dysplasia. Abnormalities usually affect the
circle of Willis arteries and their branches, and the basilar,
cerebellar, and intracranial vertebral arteries. The arterial
narrowing (see Figure 1) is smoothly tapering, often severe,
and interspersed with segments of abnormal dilatation, giving
a " sausage-on-a-string " appearance.21 Angiographic
changes progress centripetally, are dynamic, and resolve
within days to weeks. Transcranial Doppler ultrasound may
show elevated blood flow velocities;11,48,55,62-64 however,
WSO December 2023 – Issue 3

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