[Dual-energy CT angiography for evaluation of internal carotid artery stenosis and occlusion].
OBJECTIVE
To compare the feasibility of bone and calcified plaque subtracted dual-energy CT angiography (CTA) with time of flight magnetic resonance angiography (TOF MRA) in evaluation of internal carotid artery atherosclerosis.


METHODS
Totally 32 patients received a dual-energy CTA scan, along with a cerebral TOF MRA scan before or after CTA examination from one day to one month. Dual-energy software was used for bone and calcified plaque subtraction. Five anatomical segments were described for each internal carotid artery according to Fischer (1938). Ratings were based on a 1-4 scale for the dual-energy CTA maximum intensity projection (MIP) image: 1 not diagnostic, 2 partially diagnostic, 3 diagnostic, and 4 excellent. Lesions were categorized as mild (0-29%), moderate (30%-69%), severe (70%-99%), or occluded (no flow detected). Stenosis of internal carotid artery was evaluated based on post-subtracted CTA images and TOF MRA images.


RESULTS
In 320 arterial segments, 99% of arterial segments were > or = 3 score. Grading of stenosis on dual-energy CTA agreed with grading of stenoses on MRA images in 98% of arteries. In the mild and occlusion group, the agreement was 100% respectively. In the moderate and severe group, dual-energy CTA showed more severe stenosis than MRA in 7 vessels and there was significant difference between the results from the two different modalities (Z = -3.071, P = 0.002).


CONCLUSIONS
Dual-energy CTA can be used to assess the stenosis of internal arteries around skull base, but may exaggerate the severe stenosis of cerebral arteries compared with TOF MRA.
Chen
Yu
Y
Department of Radiology, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
Xue
Hua-Dan
HD
Jin
Zheng-Yu
ZY
Liu
Wei
W
Sun
Hao
H
Wang
Xuan
X
Zhao
Wen-Min
WM
Wang
Yun
Y
Mu
Wen-Bin
WB
D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods; D002343:Carotid Artery, Internal / Q000473:pathology*; D016893:Carotid Stenosis / Q000175:diagnosis*; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*