Optimization Of The Scanning Technology Of 64-detector Spiral CT Angiography In Cervical Anterior Spinal Artery

ObjectiveTo discuss the optimal scanning technology in predicting the scan-delay-time after contrast medium administration of the cervical anterior spinal artery and the best scanning parameters with 64-detector spiral CT angiography,to acquire an reliable inspection program.Materials and MethodsA total 150 patients were collected, who underwent enhanced CT examination of the neck,thyroid and so on. from June 2013 to february 2014 in our hospital, age from 40 to 96 years old,mean (57.71±15.09) years old, male 76,female 74. All patients were randomly divided into groups by the envelope method. Group A(bolus tracking with 90-mL main bolus):90 cases were randomly divided into 6 groups, marked A1-A6,15 cases per group,. The vertebral artery of the C4-5 intervertebral level was selected as monitoring area. Threshold were set respectively 80Hu、100Hu、120H、140Hu、 160Hu、180Hu, Triggered angiographic acquisition manually as soon as it reached the threshold. Group B (30-mL test bolus with 90-mL main bolus):60 cases were randomly divided into 4 groups, marked B1-B4,15 cases per group. Bolus peak time of the C4-5 intervertebral level vertebral artery wsa tested. Then scan delay time was set separately as follows:peak time plus 2s、peak time plus 4s、peak time plus 6s、 peak time plus 8s. All images were observed by two senior radiologists using double blind method on post-processing workstation. Reference 4 Grading proposed by Yang-hua and other. Visually rated the displaying case of ASA, calculated the display rate of ASA(display rate=number of good developing/the total number of cases* 100%), to find the best threshold and the best delay time after peak attenuation, the actual scan delay time were calculated respectively for the highest display rate groups of A and B. Attenuation value were measured in the vertebral artery and ASA of C4-5 intervertebral level. ANOVA was used to compare results.Results1. Group A (Bolus-tracking):the display rate and quality score of different thresholds groups, respectively were groupAl:26.57%、2.00±0.93, group A2:33.33%、 2.20±1.01. group A3:73.33%,3.00±0.93, group A4:46.67%,2.40±0.99, group A5: 42.86%,2.20±1.08, group A6:20.00%,1.80±0.94.So.Group A3 showed the highest rate. There was statistically significance of quality score difference between group A3 and group A1、 A2、A4、A5、A6 (p<0.05)2. Group B (Test-bolus):the display rate and quality score of different delay time groups,respectively were:group B1:40.00%,2.27±1.03, group B2:80.00%,3.07±0.88,group B3:53.33%,2.47±1.13, group B4:33.33%,2.03±0.69. Group B2 showed the highest rate. There was statistically significance of quality score difference between group B2 and group B1、B3、B4 (p<0.05)3. Group B2 showed higher display rate than group A3, However, there was no significant difference of the quality score (P> 0.05). Attenuation values in the vertebral artery and ASA of C4-5 intervertebral level for group A3 were respectively (415.83±99.12) Hu、(99.67±24.79) Hu, and for group B2 were respectively (365.40±115.51) Hu、(85.00±23.16) Hu. There was no statistical significance of attenuation values difference between group A3 and group B2 (P> 0.05)4. The actual scan delay time of group A3 and group B2 respectly were (22.11±5.30) s and (23.80±7.46) s. There was no statistical significance of actual scan delay time difference between group A3 and group B2 (P> 0.05). However, the fluctuation about actual scan delay time of group B2 was bigger than that of group A3. Individual difference was significant (16-36s), the difference was 20s.Conclusions1.64-detector spiral CT can successfully display most of ASA in the cervical region.2. When examed with 64-detector spiral CT for ASA CTA in the cervical region,the vertebral artery of the C4-5 intervertebral level was selected as monitoring area.If we use the Bolus-tracking technology,the best attenuation value to display cervical ASA was 120 Hu. If we use the Test-bolus technology, the best scan delay time was peak time plus 4s.3.Regardless of using the Bolus-tracking technology or the Test-bolus technology, there was a high success rate to show the ASA in cervical region by 64-detector spiral CT. Both of them can be used to check cervical ASA. And Test-bolus technology reflects the individual principle better than Bolus-tracking technology,which can be used as a noninvasive vascular imaging of the cervical ASA for the first choice.