Incidence of unilateral distal vertebral artery aplasia: evaluation by combining basiparallel anatomic scanning-magnetic resonance imaging (BPAS-MRI) and magnetic resonance angiography.
OBJECTIVE
The incidence of a unilateral aplastic distal vertebral artery (VA) has been reported as 0.2% of cases on cerebral angiography. During our daily magnetic resonance (MR) examinations, however, we frequently encounter MR angiograms (MRAs) that do not demonstrate unilateral VA. The purpose of this study was to calculate the frequency of aplastic unilateral distal VA by MR images performed for asymptomatic people.


METHODS
Over a time span of 1 year, 237 asymptomatic people (140 men, 97 women; ages 28-67 years, mean 54.4 years) underwent brain MRI during a "brain check-up examination" in our hospital. To identify an aplastic unilateral distal VA, we retrospectively compared three-dimensional time-of-flight MRA with basiparallel anatomic scanning (BPAS)-MRI which was designed for recognition of the arterial outer contour.


RESULTS
Aplasia of the unilateral distal VA was confirmed in 11 persons (4.6%). According to our classification, hypoplastic distal VA in 12 (5.1%) and asymptomatic acquired unilateral distal VA occlusion was also proved in 2 (0.8%).


CONCLUSIONS
We found that the frequency of aplastic unilateral VA was 4.6% in asymptomatic people using a combination of MRA and BPAS-MRI for assessment of an intracranial VA.
Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. koheim@cc.hirosaki-u.ac.jp
Kohei
K
Morimoto
Morio
M
Nagahata
Shuichi
S
Ono
Hiroyuki
H
Miura
Fumiyasu
F
Tsushima
Hiroko
H
Seino
Shinya
S
Kakehata
Kiyoshi
K
Basaki
Seiyu
S
Uno
Yoshinao
Y
Abe
D000328:Adult; D000368:Aged; D001157:Arterial Occlusive Diseases / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014711:Vertebral Artery / Q000002:abnormalities*