Objective: Our goal was to assess whether significant secondary athero
sclerotic changes from radiation can be detected on SE MR of the neck.
Materials and Methods: Pre- and postradiation MR scans of 16 patients
with head and neck malignancies were studied randomly, independently,
and blindly by two readers to determine the frequency of narrowing of
the carotid arterial lumen and obliteration of the carotid space with
in the carotid sheath. Results: Interval narrowing of either the commo
n, internal, or external carotid artery lumen was seen in 108 of 192 (
56%) of vessels evaluated on postradiation MR scans compared with prer
adiation studies. The differences in the grades of vessel luminal diam
eter were statistically significant (p < 0.05 for one reader and p < 0
.0001 for the other reader). Among the 16 patients, 3 patients had ves
sels with a critical degree of stenosis, newly appearing on postradiat
ion scans. Seven of 16 patients had diffuse obliteration of the planes
within the carotid space. Conclusion: The incidence of accelerated at
herosclerosis from therapeutic radiation may be greater than expected
in nonirradiated patients. Magnetic resonance scans are an effective,
noninvasive method for this type of follow-up.