BACKGROUND AND PURPOSE: Occasionally we have observed anecdotal cases of as
ymptomatic hyperintensities on diffusion-weighted MR (DW-MR) examinations o
f the brain of patients who previously underwent routine cerebral angiograp
hy, These observations, as well as MR imaging and transcranial Doppler data
in the literature suggesting a high rate of procedure-associated emboli, r
aise concern regarding the underdiagnosis of asymptomatic focal infarction
associated with cerebral angiography.
In order to determine whether asymptomatic diffusion abnormalities are freq
uently associated with procedures, we prospectively obtained DW-MR images b
efore and after routine cerebral angiography,
METHODS: Twenty consecutive patients, who met protocol criteria and receive
d a routine three- or four-vessel diagnostic cerebral angiogram at our inst
itution, were evaluated. Using a Bayesian estimate to establish an upper bo
und for the incidence of an event with zero occurrences in a study sample,
the study group size was selected to exclude a 10% incidence of abnormaliti
es revealed by DW-MR imaging of patients who underwent previous cerebral an
giography, Two neuroradiologists evaluated imaging studies.
RESULTS: Neither clinical signs nor abnormalities on DW-MR images were foun
d, which suggested no infarction after angiography in our patient sample, B
ased on this data, an upper bound of 9% (95% confidence) is predicted for t
he appearance of abnormalities revealed by DW-MR imaging after cerebral ang
iography.
CONCLUSION: Cerebral angiography is associated with an incidence of asympto
matic cerebral infarction of no more than 9%, It well may be substantially
lower than this estimate; a more accurate evaluation of the true incidence
would require a significantly larger study population, This test provides a
convenient noninvasive means of assessing procedure-related cerebral infar
ction, such as that which occurs after carotid endarterectomy or vascular a
ngioplasty and stenting.