Intravenous Three-Dimensional Digital Subtraction Angiography Of Cerebral Vessels And Clinical Application

PART1THE FEASIBILITY OF INTRAVENOUS THREE-DIMENSIONAL DIGITAL SUBTRACTION ANGIOGRAPHY OF CEREBRAL VESSELSEXPERIMENT1INFLUENCE OF INTRAVASCULAR CONTRAST MEDIUM IODINE CONCENTRATION ON VCTDSA IMAGE QUALITYPurpose:To investigate the influence of different intravascular contrast medium iodine concentration on the volume computed tomograp-hic digital subtraction angiography (VCTDSA) image quality, and to deter-mine the CT threshold values for showing the vessels best.Materials and Methods:Consecutive60cases of intravascular CT values of VCTDSA were included in this study. The extra cranial left internal carotid artery (LEICA), the M1segment of left middle cerebral artery (LM1), the A2segment of left anterior cerebral artery (LA2), the left intracranial vertebral artery (LIVA) and basilar artery (BA) were involved, head and neck CTA, plus measured left external carotid artery (LECA), if vascular lesions existed, the contralateral vessel would be measured. Then the conventional and subtraction CTA image quality was evaluated, respectively.Results:In the LEICA, LIVA, BA and LECA conventional and subtraction groups, LM1conventional group:grade Ⅰ and Ⅱ groups performed statistically significant differences with grade Ⅲ group (P<0.017), grade Ⅰ group showed no significant difference with grade Ⅱ group(P>0.017). In the LM1subtraction group, LA2conventional and subtraction groups:grade Ⅰ, Ⅱ and Ⅲ group pairwise comparisons, there were statistically significant differences(P<0.017). CT threshold values of the best CT image quality:LM1segment subtraction group:506±89HU, LA2segment conventional group:460±67HU, LA2segment subtraction group436±60HU, respectively.Conclusion:With cerebral intravascular contrast medium iodine concentration increasing, the degree of vascular enhancement increased, which was beneficial to improve image quality. EXPERIMENT2EXPERIMENTAL STUDY ON TEST TUBES WITH DIFFERENT CONTRAST MEDIUM IODINE CONCENTRATIONS IMITATE VESSELSPurpose:To investigate whether the cerebral intravascular contrast medium iodine concentrations on VCTDSA (experiment1) can meet the request of3D DSA.Materials and Methods:Nine test tubes filled with different contrast medium iodine concentrations (100to600HU) were scanned by VCTDSA, then the iodine concentrations were measured and the original data were reconstructed with three dimensional technology. The same tubes were scanned by three dimensional rotational angiography (3D RA) and reconstructed with three dimensional technology. Then the image quality of VCTDSA and3D DSA was compared.Results:The CT values from1to9vessel models on CT axial image were104HU,172HU,216HU,262HU,369HU,392HU,445HU,507HU and555HU, respectively. No significant difference of image quality was found between VCTDSA and3D DSA (Z=0.000,P>0.05). In3D DSA, the image quality of the vessel models with contrast medium iodine concentration>300HU (5to9vessel models) was grade I, which was similar to VCTDSA. Conclusion:The cerebral intravascular contrast medium iodine concentration on VCTDSA (experiment1) can meet the request of3D DSA. PART2INFLUENCING FACTORS OF TIME TO START SCANNING IN CEREBRAL VESSELS IN VCTDSAPurpose:To investigate the influencing factors of time to start scanning in cerebral vessels in VCTDSA, determine the main factors and the correlation between them.Materials and Methods:Collecting115cases of cerebral vascular VCTDSA, patient’s gender, age, height and weight, heart rate, venous access site, contrast medium concentration and volume, injection duration time and rate, saline flush volume and rate, smoking history, hypertension, coronary artery disease, diabetes, high blood-fat, intracranial aneurysm, intracranial arteriostenosis, intracranial vascular malformations, intracranial tumors and so on were recorded, then the body mass index was calculated. The correlation of the above factors and the time to start scanning were analyzed.Results:The qualitative data such as sex, venous access site, smoking history, hypertension, coronary disease, diabetes, high blood-fat, intracranial aneurysm, intracranial arteriostenosis, intracranial vascular malformation, intracranial tumor and so on were compared between groups with t test, all P>0.05. The multivariate gradually regression analysis was adopted for analysing the quantitative data such as age, height and weight, the body mass index, heart rate, contrast medium concentration and volume, injection duration time, injection rate, saline flush volume and rate (the entry value P=0.10and the removal value P=0.15). The P values of height, contrast medium concentration and volume, injection duration time, heart rate, saline flush volume were all<0.1. The Beta values of height, contrast medium concentration, contrast medium volume, injection duration time, heart rate, saline flush volume were0.1176,-0.1486,0.4071,0.3173,-0.2625,0.2306, respectively. Recommended formula of time to start scanning(s)=9.4142+height(cm)×0.0424-contrast medium concentration (mgI/ml)×0.0328+contrast medium volume(ml)×0.2051+injection duration time(s)×0.323-heart rate(beats/min)×0.0537+saline flush volume (ml)×0.0957.The associations between height, contrast medium concentration and volume, injection rate, injection duration time, heart rate, saline flush volume and the time to start scanning were analyzed with Pearson correlation analysis. The P values of height, contrast medium concentration were both>0.05.The P values of contrast medium volume, injection rate, injection duration time, heart rate, saline flush volume were all<0.05. The r values of contrast medium volume, injection rate, injection duration time, heart rate, saline flush volume were0.6267,-0.2783,0.5337,-0.3620,0.3862, respectively.Conclusion:Height, contrast medium concentration and volume, injection duration time, heart rate, saline flush volume were main influencing factors of time to start scanning; and among them, contrast medium volume and injection duration time (also injection rate)were the most important factors of time to start scanning. The other factors had not serious influence. PART3INITIAL CLINICAL APPLICATION OF INTRAVENOUS THREE-DIMENSIONAL DIGITAL SUBTRACTION ANGIOGRAPHY OF CEREBRAL VESSELSPurpose:To evaluate the feasibility of intravenous three-dimensional digital subtraction angiography (Ⅳ3D DSA) in cerebral vessels, and to compare the image quality of IV3D DSA with that of VCTDSA.Materials and Methods:IV3D DSA was performed in21patients with intracranial aneurysm clipped surgery who had undergone VCTDSA. Contrast medium was injected in the antecubital vein, and then3D DSA was performed to patients. The3D raw volume data were transferred to3D workstation, processed and presented.Results:In Ⅳ3D DSA,2of21patients failed. In the19patients successed in the examination,20aneurysm clips were all clearly displayed (one had two aneurysm clips), the aneurysms showed completely clipped and the parent arteries were unobstructed in12of19patients, the parent arteries showed not very well because of motion artifacts in7of19patients. The main cerebral vessels showed well in most of the19patients. The image quality grade Ⅱ, Ⅲ, Ⅳ were10.5%(2/19),84.2%(16/19),5.3%(1/19), respectively; In VCTDSA, all the aneurysm clips and parent arteries showed well, the image quality grade Ⅰ,Ⅱ, Ⅲ were36.8%(7/19),42.1%(8/19),21.1%(4/19), respectively. Significant difference of image quality was found between Ⅳ3D DSA and VCTDSA (Z=-3.782,P<0.05).Conclusion:Ⅳ3D DSA was feasible, but its image quality was not as well as VCTDSA. It needed to optimize the imaging parameters to improve the image quality.