Gemstone spectral imaging reduced artefacts from metal coils or clips after treatment of cerebral aneurysms: a retrospective study of 35 patients.
OBJECTIVE
This study aimed to evaluate the effect of gemstone spectral imaging (GSI) for metal artefact reduction in cerebral artery CT angiography (CTA) after metal coils or clips treatment.


METHODS
35 patients with cerebral aneurysms were treated with metal coils or clips and underwent CTA using gemstone spectral CT between February and December 2013. The data were reconstructed into three image groups including Group A (quality check images with 140 kVp), Group B (monochromatic image sets in the range of 40-140 keV) and Group C [monochromatic image sets with metal artefacts reduction software (MARS GE Medical Systems, Waukesha, WI)]. CT attenuation value of cerebral artery, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and the subjective score of all images were measured and compared statistically.


RESULTS
CT attenuation value of cerebral artery decreased in Groups B and C as the photon energy increased. The average energy levels of 60.05 ± 5.37 and 59.93 ± 5.57 keV presented the best CNR in Groups B and C, respectively. CNR values, SNR values and the subjective scores of the image quality of the two sets were higher than those of Group A.


CONCLUSIONS
GSI reduced metal artefact and improved the image quality of CTA after metal coils or clips treatment in patients with cerebral aneurysm. The monochromatic images at the average energy level of 60.05 ± 5.37 keV with MARS and 59.93 ± 5.57 keV without MARS were suggested to be the optimal parameters.


CONCLUSIONS
GSI could reduce metal artefact after metal coils or clips treatment in patients with cerebral aneurysm.
1 Department of CT, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Yulin
Y
Jia
1 Department of CT, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Jinling
J
Zhang
1 Department of CT, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Jinyu
J
Fan
2 Department of Medical Imaging, Heilongjiang Provincial Hospital, Harbin, China.
Chao
C
Li
3 Department of CT, The First Hospital of Harbin, Harbin, China.
Yuanyuan
Y
Sun
1 Department of CT, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Di
D
Li
1 Department of CT, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Xigang
X
Xiao
D000328:Adult; D000368:Aged; D016477:Artifacts; D002533:Cerebral Angiography; D003287:Contrast Media; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy*; D007472:Iohexol / Q000031:analogs & derivatives; D008670:Metals; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio; D012984:Software; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D008670:Metals; D007472:Iohexol; C038192:iopromide