Improved methods of imaging the cerebral vascular system have increase
d the detection of traumatic or spontaneous dissection of the vertebra
l and carotid arteries. Especially MRI allows direct demonstration of
intramural hematomas that are a sign of dissection of the vessel wall.
We report on a patient who had an acute onset of dysarthria and monoc
ular blurred vision, which recurred several times. Doppler ultrasound
showed stenosis in both internal carotid arteries with reduced velocit
y of the flow;angiography confirmed the stenosis, showing a long stret
ch of stenosis (70%) of the right and a short stretch of stenosis (60%
) of the left internal carotid arteries. MRI demonstrated a narrowing
of the lumen by an intramural mass, whose signal characteristics were
typical for blood. The MRI findings were thus consistent with the diag
nosis of a spontaneous dissection of the carotid arteries. Since the D
oppler ultrasound follow-up showed no change during the following 3 da
ys, we interpreted the MRI findings as an indication of bleeding in an
atheroma. The carotid disobliteration, performed first on the left si
de and later on the right side, confirmed this interpretation. Since s
tenosis due to a fissuring atheroma or bleeding in an atheroma require
s different therapy than a dissection, it is thus important to conside
r the possible differential diagnosis in interpreting the MRI.