Comparison of NASCET and WASID criteria for the measurement of intracranial stenosis using digital subtraction and computed tomography angiography of the middle cerebral artery

A Comparative Study of Transcranial Color-Coded Doppler (TCCD) and Transcranial Doppler (TCD) Ultrasonography Techniques in Assessing the Intracranial Cerebral Arteries Haemodynamics

Cerebrovascular disease (CVD) poses a major public health and socio-economic burden worldwide due to its high morbidity and mortality rates. Accurate assessment of cerebral arteries' haemodynamic plays a crucial role in the diagnosis and treatment management of CVD. The study compared a non-imaging transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in quantifying middle cerebral arteries (MCAs) haemodynamic parameters. A cross-sectional study involving 50 healthy adults aged ≥ 18 years was conducted. The bilateral MCAs were insonated via three trans-temporal windows (TTWs-anterior, middle, and posterior) using TCD, cTCCD, and ncTCCD techniques. The MCA peak systolic velocity (PSV) and mean flow velocity (MFV) were recorded at proximal and distal imaging depths that could be visualised on TCCD with a detectable spectral waveform. A total of 152 measurements were recorded in 41 (82%) subjects with at least one-sided open TTW across the three techniques. The mean PSVs measured using TCD, ncTCCD, and cTCCD were 83 ± 18 cm/s, 81 ± 19 cm/s, and 93 ± 21 cm/s, respectively. There was no significant difference in PSV between TCD and ncTCCD (bias = 2 cm/s, p = 1.000), whereas cTCCD yielded a significantly higher PSV than TCD and ncTCCD (bias = -10 cm/s, p < 0.001; bias = -12 cm/s, p ≤ 0.001, respectively). The bias in MFV between TCD and ncTCCD techniques was (bias = -0.5 cm/s; p = 1.000), whereas cTCCD demonstrated a higher MFV compared to TCD and ncTCCD (bias = -8 cm/s, p < 0.001; bias = -8 cm/s, p ≤ 0.001, respectively). TCCD is a practically applicable imaging technique in assessing MCA blood flow velocities. cTCCD is more accurate and tends to give higher MCA blood flow velocities than non-imaging TCD and ncTCCD techniques. ncTCCD is comparable to non-imaging TCD and should be considered in clinical cases where using both TCD and TCCD measurements is needed.

Sub-satisfactory recanalization of severe middle cerebral artery stenoses can significantly improve hemodynamics

Purpose

To investigate the effect of sub-satisfactory stent recanalization on hemodynamic stresses for severe stenoses of the middle cerebral artery (MCA) M 1 segment.

Materials and methods

Patients with severe stenoses of the MCA M1 segment treated with endovascular stent angioplasty were retrospectively enrolled. Three-dimensional digital subtraction angiography before and after stenting was performed; the computational fluid dynamics (CFD) analysis of hemodynamic stresses at the stenosis and normal segments proximal and distal to the stenoses was analyzed.

Results

Fifty-one patients with severe stenosis at the MCA M1 segment were enrolled, with the stenosis length ranging from 5.1 to 12.8 mm (mean 9 ± 3.3 mm). Stent angioplasty was successful in all (100%) the patients. The angiography immediately after stenting demonstrated a significant (P &lt; 0.05) decrease in MCA stenosis after comparison with before stenting (31.4 ±12.5% vs. 87.5 ± 9.6%), with residual stenosis of 15–30% (mean 22.4 ± 3.5%). Before stenting, the total pressure was significantly higher (P &lt; 0.0001), while the WSS, velocity, and vorticity were all significantly decreased (P &lt; 0.0001) at the normal arterial segment proximal to the stenosis, and the total pressure, WSS, velocity, and vorticity were all significantly decreased (P &lt; 0.0001) at the normal arterial segment distal to the stenosis compared with those at the stenosis. After sub-satisfactory stenting recanalization, all the hemodynamic stresses proximal or distal to the stenosis and at the perforator root were improved compared with those before stenting and were similar to those after virtual stenosis removal.

Conclusion

Sub-satisfactory recanalization of severe MCA stenoses can significantly improve the hemodynamic status for cerebral perfusion at the stenoses.

Prevalence, prognosis, and treatment of atherosclerotic intracranial stenosis in Caucasians

BACKGROUND

Intracranial atherosclerotic stenosis is a highly prevalent cause of stroke worldwide with important ethnic disparities. Widely considered to be a common cause of stroke in Asian and Afro-Caribbean populations, relatively less is known about the burden and significance of intracranial atherosclerotic stenosis in Caucasians.

AIMS

We aim to highlight recent insights and advances into the prevalence, prognosis, and treatment of symptomatic and asymptomatic atherosclerotic intracranial atherosclerotic stenosis in Caucasian patients.

SUMMARY OF REVIEW

We identified 48 articles studying intracranial atherosclerotic stenosis in Caucasian patients with ischemic stroke or transient ischemic attack. Most studies were on hospital-based cohorts of consecutive patients and half were graded as "fair" quality. There was significant variation between studies in the definition of intracranial atherosclerotic stenosis and in the imaging modalities used to detect intracranial atherosclerotic stenosis. Overall, 12.1% of Caucasian patients were found to have any intracranial atherosclerotic stenosis, 6.4% symptomatic intracranial atherosclerotic stenosis and 11.1% asymptomatic intracranial atherosclerotic stenosis, with higher rates at older ages. In studies reporting prognosis, there were 61 and 10 same-territory ischemic strokes in 1000 person-years in patients with symptomatic and asymptomatic intracranial atherosclerotic stenosis, respectively. Percutaneous stenting and angioplasty have not proven superior to intensive medical management in patients with symptomatic intracranial atherosclerotic stenosis.

CONCLUSIONS

Intracranial atherosclerotic stenosis has previously been neglected as a cause of stroke in Caucasians but is highly prevalent at older ages and frequently discovered with the growing use of noninvasive angiography. Intensive medical therapy is the treatment of choice, but there is a need to develop novel treatments or therapeutic approaches to lower the risk of stroke in higher risk patients.

Utility of minimum intensity projection images based on three-dimensional CUBE T1 weighted imaging for evaluating middle cerebral artery stenosis

OBJECTIVE

This study investigated the diagnostic performance of MinIP images based on three-dimensional variable-flip-angle turbo spin echo T₁ weighted imaging (3D CUBE T₁WI) from high-resolution vessel wall magnetic resonance imaging for detecting middle cerebral artery (MCA) stenosis.

METHODS

A total of 63 consecutive patients were included in this study. MinIP images were reconstructed using 3D CUBE T₁WI as the source images. The degree and length of MCA stenosis were measured on MinIP images and were compared with digital subtraction angiography (DSA) as the reference standard.

RESULTS

The intra- and interobserver agreement for both the rate and length of MCA stenosis were excellent for the MinIP images. There was also excellent agreement in the degree of MCA stenosis calculated using MinIP images and DSA. MinIP images had a high sensitivity, specificity for diagnosing MCA stenosis. There was a good correlation between the two methods for measuring the rate and length of MCA stenosis.

CONCLUSION

MinIP images based on 3D CUBE T₁WI are highly consistent with DSA for evaluating the degree and length of MCA stenosis.

ADVANCES IN KNOWLEDGE

MinIP images can be produced as a derivative from vessel wall imaging and implemented as an adjunct to vessel wall imaging without extra acquisition time.

Prevalence and outcome of young stroke patients with middle cerebral artery stenosis

Background

Etiologies of acute ischemic stroke in young adults are heterogeneous. Middle cerebral artery (MCA) stenosis is a common finding in Asians which may be an important cause of stroke in young adults. However, studies of stroke in young Asian populations are rare. Our study was to investigate the prevalence and outcome of young stroke patients with MCA stenosis in Chinese populations.

Methods

Young patients with MCA territory infarction between January 2013 and September 2018 were retrospectively recruited. Subjects were defined as stenosis group (MCA stenosis ≥50%) and no-stenosis group (MCA stenosis<50% or no stenosis) by their MCA stenosis. For patients in stenosis group, they were categorized as uni-MCA stenosis subgroup and multiple stenosis subgroup. Demographic data, risk factors, imaging feature and complications were compared between groups. Prevalence of MCA stenosis and risk factor score (score ≥ 2 or 3) in different age groups were investigated. Modified Rankin Scale (mRS) was used for evaluating functional outcome at discharge (unfavorable outcome: 3–6). Binary logistic regression was performed to determine independent risk factors of unfavorable outcome.

Results

Two hundred forty-nine young stroke patients were included in our study and 110 (44.2%) patients were defined as stenosis group. 55 (50%) patients were categorized as uni-MCA stenosis subgroup and 55 (50%) were multiple stenosis subgroup. The most common traditional vascular risk factors included hypertension, hyperlipemia, smoking, hyperhomocysteinemia and alcohol consumption. Prevalence of risk factor score ≥ 2 or 3 increased with age, but not incidence of MCA stenosis. By TOAST classification, the most common etiologies were large-artery atherosclerosis (41.0%) and small vessel disease (33.7%). Compared with no-stenosis group, patients in stenosis group were more likely to have large territorial infarct, develop complications and have unfavorable outcome. No significant difference was found between patients in uni-MCA stenosis and multiple stenosis subgroups except history of stroke/TIA, risk factor score ≥ 3 and silent infarct. By logistic regression, hypertension (OR = 3.561; 95%CI, 1.494 to 8.492; p = 0.004), NIHSS scores at admission (OR = 1.438; 95%CI, 1.276 to 1.620; p = 0,000) and infarct size (p = 0.015) independently predicted unfavorable outcome.

Conclusions

Forty-four point two percent young Chinese adults with MCA territory infarction had MCA stenosis. Prevalence of MCA stenosis did not increase with age. Patients with MCA stenosis had worse clinical outcome, however, only hypertension, NIHSS scores at admission and infarct size were independent predictors.

Quantification of intracranial arterial stenotic degree evaluated by high-resolution vessel wall imaging and time-of-flight MR angiography: reproducibility, and diagnostic agreement with DSA

OBJECTIVES

The purpose of this study was to compare the reproducibility and diagnostic agreement of high-resolution vessel wall imaging (HR-VWI) and time-of-flight magnetic resonance angiography (TOF-MRA) with digital subtraction angiography (DSA) to evaluate intracranial arterial stenosis.

METHODS

We retrospectively enrolled patients who underwent HR-VWI and TOF-MRA with suspected intracranial artery disease and had DSA results from our institutional imaging database. Two neuroradiologists separately and independently evaluated anonymous image data for the stenotic lesions. DSA was analyzed by two neurointerventionalists and it served as a standard criterion. The reproducibility of these two MR techniques was determined by the intraclass correlation coefficients (ICCs). The diagnostic agreement to DSA was assessed by the concordance correlation coefficients (CCCs).

RESULTS

A total of 246 lesions from 106 individuals were analyzed for stenotic degrees. The total intra-observer and inter-observer reproducibility of HR-VWI was excellent for identifying stenosis and better than of TOF-MRA. The overall concordance of HR-VWI with DSA was excellent with CCC = 0.932, whereas TOF-MRA was 0.694. In addition, HR-VWI could provide additional vessel wall information.

CONCLUSIONS

HR-VWI has more advantages over TOF-MRA, such as better reproducibilities and diagnostic agreements with DSA to analyze intracranial arterial stenosis. It provides additional information that helps in clinical diagnosis and management.

KEY POINTS

• High-resolution vessel wall imaging can assess intracranial arterial stenosis with a better reproducibility than TOF-MRA and has a higher diagnostic agreement with DSA. • High-resolution vessel wall imaging had a higher diagnostic agreement with DSA compared with TOF-MRA. • Apart from evaluating vascular stenosis, HR-VWI provided additional vessel wall information to help in clinical diagnosis.

Correlation between intracranial vertebral artery stenosis diameter measured by digital subtraction angiography and cross-sectional area measured by optical coherence tomography

Background

Intracranial vertebral artery (V4 segment) stenosis quantification traditionally uses the narrowest stenosis diameter. However, the stenotic V4 lumen is commonly irregularly shaped. Optical coherence tomography (OCT) allows a more precise calculation of V4 geometry. We compared the narrowest diameter stenosis (DS), measured by digital subtraction angiography (DSA), with the area stenosis (AS), measured by OCT. We hypothesized that DS is the gold standard for measuring the degree of stenosis.

Methods

Five neuroradiologists evaluated 49 stenosed V4 segments in a blinded protocol. V4 stenosis was measured in millimeters on DSA at its narrowest diameter. OCT was used to estimate the cross-sectional luminal area. We also used automated software to measure DS. Three different angles (anterior, lateral, and oblique views) were used for calculations, and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin–Aspirin Symptomatic Intracranial Disease (WASID) methods were used in all measurements. Spearman’s R values were calculated. Non-linear regression analysis was performed between the DS and AS, with statistically different correlations.

Results

A high correlation was observed between the WASID and NASCET methods to measure DS with observer measurement and automated software. A good correlation was found between DS measured by observers and AS measured by OCT. Non-linear regression analysis showed that only observer measurement using the oblique view and the WASID method could attain statistically significant differences, but it was weak (r=0.389).

Conclusion

Measurement of the narrowest diameter was not a reliable predictor of the cross-sectional area of V4 stenosis. Larger studies are therefore needed to develop a new evaluation system based on V4 stenosis.

3D Black-Blood Luminal Angiography Derived from High-Resolution MR Vessel Wall Imaging in Detecting MCA Stenosis: A Preliminary Study

BACKGROUND AND PURPOSE

3D high-resolution vessel wall imaging is increasingly used for intracranial arterial diseases. This study compared the diagnostic performance of black-blood luminal angiography derived from 3D vessel wall imaging with source images of vessel wall imaging and TOF-MRA in detecting middle cerebral artery stenosis.

MATERIALS AND METHODS

Sixty-two patients with suspected MCA atherosclerosis underwent TOF-MRA, vessel wall imaging, and CTA. Intracranial black-blood luminal angiography was created from source images of vessel wall imaging using minimum intensity projection. The degree and length of MCA stenosis were measured on source images of vessel wall imaging, TOF-MRA, and black-blood luminal angiography and compared using CTA as a reference standard.

RESULTS

The image quality of black-blood luminal angiography was diagnostic in most patients. The intra- and interobserver agreement for both stenosis degree and length measurements was excellent for black-blood luminal angiography. It was comparable with that of source images of vessel wall imaging in grading stenosis. Compared with TOF-MRA, black-blood luminal angiography showed significantly higher sensitivity for the detection of severe stenosis (89.3% versus 64.3%, P = .039) and higher specificity for the detection of occlusion (95.4% versus 84.6%, P = .039). Lesion length estimated on source images of vessel wall imaging was significantly greater than that measured by CTA and black-blood luminal angiography (P < .001 and P = .010).

CONCLUSIONS

Black-blood luminal angiography is better than TOF-MRA in detecting severe stenosis and occlusion of the MCA. Compared with source images of vessel wall imaging, it is more accurate in evaluating stenosis length. Black-blood luminal angiography can be produced as a derivative from vessel wall imaging and implemented as an adjunct to vessel wall imaging and TOF-MRA without extra acquisition time.

Comparison of High-Resolution MR Imaging and Digital Subtraction Angiography for the Characterization and Diagnosis of Intracranial Artery Disease

BACKGROUND AND PURPOSE

High-resolution MR imaging has recently been introduced as a promising diagnostic modality in intracranial artery disease. Our aim was to compare high-resolution MR imaging with digital subtraction angiography for the characterization and diagnosis of various intracranial artery diseases.

MATERIALS AND METHODS

Thirty-seven patients who had undergone both high-resolution MR imaging and DSA for intracranial artery disease were enrolled in our study (August 2011 to April 2014). The time interval between the high-resolution MR imaging and DSA was within 1 month. The degree of stenosis and the minimal luminal diameter were independently measured by 2 observers in both DSA and high-resolution MR imaging, and the results were compared. Two observers independently diagnosed intracranial artery diseases on DSA and high-resolution MR imaging. The time interval between the diagnoses on DSA and high-resolution MR imaging was 2 weeks. Interobserver diagnostic agreement for each technique and intermodality diagnostic agreement for each observer were acquired.

RESULTS

High-resolution MR imaging showed moderate-to-excellent agreement (interclass correlation coefficient = 0.892-0.949; κ = 0.548-0.614) and significant correlations (R = 0.766-892) with DSA on the degree of stenosis and minimal luminal diameter. The interobserver diagnostic agreement was good for DSA (κ = 0.643) and excellent for high-resolution MR imaging (κ = 0.818). The intermodality diagnostic agreement was good (κ = 0.704) for observer 1 and moderate (κ = 0.579) for observer 2, respectively.

CONCLUSIONS

High-resolution MR imaging may be an imaging method comparable with DSA for the characterization and diagnosis of various intracranial artery diseases.

Reproducibility of Middle Cerebral Artery Stenosis Measurements by DSA: Comparison of the NASCET and WASID Methods

Purpose

To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA).

Materials and Methods

DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman’s R value, Pearson correlation coefficient and Bland-Altman plots.

Results

Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman’s R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis.

Conclusion

Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.

A randomised comparison of transradial and transfemoral approach for carotid artery stenting: RADCAR (RADial access for CARotid artery stenting) study

AIMS

Limited data exist on radial access in carotid artery stenting. This multicentre prospective randomised study was performed to compare the outcome and complication rates of transradial and transfemoral carotid artery stenting.

METHODS AND RESULTS

The clinical and angiographic data of 260 consecutive patients with high risk for carotid endarterectomy, treated between 2010 and 2012 by carotid stenting with cerebral protection, were evaluated. Patients were randomised to transradial (n=130) or transfemoral (n=130) groups and several parameters were evaluated. Primary combined endpoint: major adverse cardiac and cerebral events, rate of access-site complications. Secondary endpoints: angiographic outcome of the procedure, fluoroscopy time and X-ray dose, procedural time, crossover rate to another puncture site and hospitalisation in days. Procedural success was achieved in all 260 patients (100%), the crossover rate was 10% in the TR and 1.5% in the TF group (p<0.05). A major access-site complication was encountered in one patient (0.9%) in the TR group and in one patient (0.8%) in the TF group (p=ns). The incidence of major adverse cardiac and cerebral events was 0.9% in the TR and 0.8% in the TF group (p=ns). Procedure time (1,620 [1,230-2,100] vs. 1,500 [1,080-2,100] sec, p=ns) and fluoroscopy time (540 [411-735] vs. 501 [378-702] sec, p=ns) were not significantly different, but the radiation dose was significantly higher in the TR group (195 [129-274] vs. 148 [102-237] Gy*cm2, p<0.05) by per-protocol analysis. Hospitalisation days were significantly lower in the TR group (1.17±0.40 vs. 1.25±0.45, p<0.05). By intention-to-treat analysis there was a significantly higher radiation dose in the TR group (195 [130-288] vs. 150 [104-241], p<0.05), but no difference in major events (0.9 vs. 0.8, p=ns) and length of hospitalisation in days (1.4±2.6 vs. 1.25±0.45, p=ns).

CONCLUSIONS

The transradial approach for carotid artery stenting is safe and efficacious; however, the crossover rate is higher with transradial access. There are no differences in the total procedure duration and fluoroscopy time between the two approaches but the radiation dose is significantly higher in the radial group, and the hospitalisation is shorter with the use of transradial access by per-protocol analysis. By evaluating the patient data according to intention-to-treat analysis we found no difference in major adverse events and hospitalisation. In both groups, vascular complications rarely occurred.

Computed Tomography Angiography in the Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Study

BACKGROUND

The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) study validated noninvasive imaging tests of intracranial atherosclerosis against catheter angiography in a prospective, blinded, multicenter setting. Critical evaluation of transcranial Doppler (TCD) and magnetic resonance angiography in the SONIA study standardized their performance and interpretation. We performed a similar analysis of computed tomography angiography (CTA) for the detection of intracranial stenosis.

METHODS

Multicenter standardization of image acquisition and blinded, central interpretation of CTA performance were conducted in concert with the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. Measurements of the intracranial arterial diameter were obtained to derive stenosis values. Correlation with catheter angiography was used to assess CTA performance characteristics.

RESULTS

CTA measurements of intracranial stenosis were obtained in 120 vessel segments, with angiographic correlation in 52. CTA was performed as a noninvasive study prior to conventional angiography. CTA stenoses of 50-99% or a flow gap were identified in 15 of 52 vessel segments, stenoses of <50% in 5 of 52, and normal arterial diameters in 32 of 52 vessel segments. Based on the digital subtraction angiography (DSA) stenosis defined as 50-99%, the positive predictive value (PPV) of CTA was only 46.7% (95% CI 21.3-73.4) and the negative predictive value (NPV) was 73.0% (95% CI 55.9-86.2). For DSA stenosis defined as 70-99%, the PPV of CTA was 13.3% (95% CI 1.7-40.5) and the NPV was 83.8% (95% CI 68.0-93.8).

CONCLUSIONS

CTA can accurately rule out the presence of severe stenosis due to intracranial atherosclerosis and may eliminate the need for angiography in many cases. Further prospective, blinded evaluation of CTA and optimization of cutpoints to predict angiographic disease will facilitate future trials of intracranial atherosclerosis.

The association between CYP2C19 genotype and of in-stent restenosis among patients with vertebral artery stent treatment

AIMS

Preventing stroke through endovascular treatment with vertebral artery stent remains a great challenge due to the occurrence of an in-stent restenosis.

MATERIALS & METHODS

In this study, a retrospective analysis was conducted in 90 patients who had been treated with VAS between 2004 and 2011 in Nanjing Drum Tower Hospital. Patients were followed up at 3 months, 6 months,and 1 year after VAS treatment and annually thereafter. For each time point, neurological function tests, vessel ultrasound and computer tomography angiography were performed to preliminarily screen the vessel stenosis. Digital subtraction angiography was used to verify the narrow sign on CTA or ultrasound. Clinical features of each patient including clopidogrel metabolization genes (CYP2C19, CYP3A4, and P2Y12) were recorded with purpose to investigate the possible risk factors for the development of ISR.

RESULTS

Single factor analysis dem-onstrated that hyperlipidemia (P < 0.05) and CYP2C19 (P < 0.01) loss-of-function geno-type increased the likelihood of ISR. A multiple logistic cox regression analysis also showed that stroke patients with hyperlipidemia (HR 3.719, 95% CI: 1.094-12.637, P = 0.035), and CYP2C19 loss-of-function genotype (HR 2.959, 95% CI: 1.325-6.610, P = 0.008) were more likely to suffer from ISR. Furthermore, CYP2C19 alleles were mainly divided into three groups: wt/wt (CYP2C19 *1/*1), wt/m (CYP2C19 *1/*2 and *1/*3), and m/m (CYP2C19 *2/*2,*2/*3 and*3/*3). Recurrent rate of ischemic stroke in m/m and wt/m groups was higher than the wt/wt group (OR: 0.141, 95% CI: 0.016-1.221, P = 0.042).

CONCLUSION

The study leads to the conclusion that hyperlipidemia and CYP2C19 impotency are possible risk factors for the development of ISR in VAS-treated patients with ischemic. Moreover, VAS-treated patients with CYP2C19 impotency were susceptible to recurrent stroke during our 54-month follow-up.

128-slice acceletated-pitch dual energy CT angiography of the head and neck: comparison of different low contrast medium volumes

BACKGROUND

Our study aims to evaluate the image quality and feasibility of 128-slice dual-energy CTA (DE-CTA) for supra-aortic arteries using reduced amounts of contrast medium (CM).

METHODS

A prospective study was performed in 54 patients receiving CTA of the head and neck with a 128-slice dual-source CT system. Patients were randomized into two groups with a volume of either 40 mL of CM (Group I) or 50 mL of CM (Group II). Arterial and venous enhancements were recorded for quantitative assessment. Qualitative assessments for images without bone removal (BR) were based on a) the visualization of the circle of Willis and b) streak artifacts due to residual CM in the subclavian or internal jugular veins ipsilateral to injection of CM. Qualitative assessment of dual-energy images using BR was based on the presence of bone remnants and vessel integrity. Quantitative data was compared using the Student t test. The χ(2) test was used for the qualitative measurements of streak artifacts in veins while the Mann-Whitney U test was used for the qualitative measurements of images with BR.

RESULTS

Arterial and venous attenuation was significantly higher in Group II (P=0.000). Image quality regarding the circle of Willis was excellent in both groups (3.90±0.30 for Group I and 4.00±0 for Group II) . Imaging of the internal jugular veins was scored higher in Group I (1.87±0.72) compared with Group II (1.48±0.51) (P=0.021). Within Group I using BR, mean scores for bone remnants did not differ significantly (P>0.05) but mean scores of vessel integrity (P<0.05) did.

CONCLUSIONS

Contrast-enhanced head and neck CTA is feasible using a scan protocol with low amounts of contrast medium (40 mL) on a 128-slice dual-energy CTA. The 40-mL protocol provides satisfactory image quality before and after dual-energy bone-removal post-processing.