Carotid CTA Research Articles

POSSIBILITIES OF RADIOLOGICAL SCAN METHODS WITH POST-PROCESSING IMAGE RECONSTRUCTION IN THE ASSESSMENT OF ATHEROSCLEROTIC PLAQUES OF THE CAROTID ARTERIES

The aim. To establish the informativeness of the methods of computed tomography angiography, ultrasound diagnostics and magnetic resonance arteriography without contrast in patients with atherosclerosis of carotid arteries. Materials and methods. During July 2022 - July 2024, 82 male patients were examined on the basis of the Neurological Pathology Diagnostic Center of the KNP "Regional Clinical Hospital of the Ivano-Frankivsk Regional Council". Forty-six of them were included in the study group with clinical signs of atherosclerotic lesions of the carotid arteries. Thirty-six patients with asymptomatic course of the carotid arteries atherosclerosis were chosen as the control group. Patients of both groups were aged 51-79 years, and were homogeneous in terms of concomitant diseases, duration of smoking and lipidogram results. Exclusion criteria from both cohorts were: the presence of arrhythmia, radiation treatment of oncological processes in the projection of the head and neck, diagnosed Alzheimer's disease or Fara's disease, lack of written informed consent to participate in the study, impaired legal capacity of the person, when the written consent cannot be considered truly conscious. CTA was performed using a 160-slice computer tomograph Aquilion Prime Toshiba Scanner TSX-302A (Toshiba) with SUREPlaque software to analyze atherosclerotic plaques and vessels in the Carotid CTA fast scanning mode. MRI of the head and neck with non-contrast MR-arteriography was performed using a 1.5 Tesla Phillips Achieva device using blood flow imaging sequences: s3DI MC (three-dimensional time of flight MR-angiography). Ultrasound of the carotid arteries was performed using the Esaote MyLab9eXP device using B-mode, Doppler mapping and elastography. Atherosclerotic plaques were assessed according to the new imaging-based classification - Carotid Plaque-RADS from 2024. The results. According to the classification of Carotid Plaque-RADS, the following results were obtained according to visualization by ultrasound and CT methods: a combination of plaques of categories from Plaque-RADS 2 to Plaque-RADS 4, considering the types of each category, was detected in patients of both groups. There was no significant difference between the groups in the assessment of the structure of the atherosclerotic plaque (p=0.616). For the study group, the detection of the higher percentage of the stenotic lumen of the vessel was statistically different (median - 68.5% (interquartile range 9.75%)) compared to the control group (median - 60.0% (interquartile range 7.5%)) (p =0.048). A comparison of the degree of stenosis by ultrasound and CTA methods was carried out, where a direct correlation of very high strength according to the Chaddock scale was established (r=0.934 (confidence interval: 0.881 – 0.964), p˂0.001). Atherosclerotic lesions were characterized by indirect signs on MRI, namely: wall filling defects, which most likely correspond to plaques, increased bends of main arteries. Conclusions. Ultrasound diagnostics and reconstructive post-processing capabilities of computed tomography were practically equivalent in assessing the degree of stenosis with high correlation strength (r=0.934) and highly informative images of atherosclerotic masses of carotid arteries, while non-contrast magnetic resonance arteriography allowed to suspect atherosclerotic lesions as an area of ​​a filling defect without detailed tissue structures.

A novel imaging biomarker for prediction of cerebrovascular ischemic events: Pericarotid fat density

BackgroundTo investigate the relationship between pericarotid fat density measured in carotid CTA and vulnerable carotid plaque. MethodsThis retrospective study included 374 participants who underwent carotid CTA between June 1, 2021, and December 1, 2021 (234 males, median age 68 years [interquartile range: 61–75]). Two groups, symptomatic and asymptomatic, were defined based on either diffusion-weighted MRI or a clinical history of acute ischemia or TIA within 6 months before or after CTA. The relationship between pericarotid fat density and cerebrovascular ischemic events was assessed using receiver operating characteristic analysis and binary logistic regression analysis. ResultsIn the symptomatic group (n = 135), mean pericarotid fat density (−63.3 ± 21.7 vs. -81.7 ± 16.9 HU, respectively; p < 0.001) and median maximum plaque thickness (4 [interquartile range: 3–6] vs. 3.7 [interquartile range: 2.6–4.7] mm, respectively; p = 0.002) were higher, while plaque density (42.1 ± 19.6 vs. 50.6 ± 20.4 HU, respectively; p = 0.001) was lower compared to the asymptomatic group. Pericarotid fat density (OR: 1.038, 95% CI: 1.023–1.053, p < 0.001) was identified as an independent predictor for symptomatic patients. The optimal cut-off value for pericarotid fat density predicting symptomatic patients was estimated as −74 HU (area under the curve: 0.753, 95% CI:0.699–0.808, p < 0.001). Inter-reader agreement for pericarotid fat density was found to be almost perfect (intraclass correlation coefficient: 0.818, 95% CI: 0.770–0.856, p < 0.001). ConclusionPericarotid fat density may serve as an imaging biomarker in predicting acute cerebrovascular ischemic events.

The predictive value of nontraditional lipid parameters for intracranial and extracranial atherosclerotic stenosis: a hospital-based observational study in China

BackgroundIschemic strokes are primarily caused by intracranial and extracranial atherosclerotic stenosis. Nontraditional lipid parameters broaden traditional lipid profiles, better reflect the metabolism and interaction between different lipid components, and optimize the predictive ability of lipid profiles for atherosclerotic diseases. This research was carried out to investigate the predictive value of nontraditional lipid parameters for intracranial or extracranial atherosclerotic stenosis.MethodsThe investigation collected data from inpatients who underwent cervical vascular ultrasonography, carotid CTA, cerebral artery CTA or MRA, and brain MRI or CT from December 2014 to December 2021. The nontraditional lipid parameters were calculated by collecting traditional lipid parameters. To evaluate the predictive power of nontraditional lipid parameters, logistic regression and receiver operating characteristic curve (ROC) analyses were performed.ResultsBased on the inclusion and exclusion criteria, 545 patients were included. According to the imaging results, inpatients were divided into two groups, including no intracranial or extracranial atherosclerotic stenosis (n = 250) and intracranial or extracranial atherosclerotic stenosis (AS, n = 295). Among them, AS was further divided into three subgroups: intracranial atherosclerotic stenosis (ICAS), extracranial atherosclerotic stenosis (ECAS) and combined intracranial and extracranial atherosclerotic stenosis (IECAS). Logistic regression analysis showed that nontraditional lipid parameters, including the atherogenic index of plasma (AIP), remnant cholesterol (RC), nonhigh-density lipoprotein cholesterol (non-HDL-C), lipoprotein combine index (LCI), atherogenic coefficient (AC), Castelli’s index-I (CRI-I) and Castelli’s index-II (CRI-II), were significantly correlated with intracranial or extracranial atherosclerotic stenosis (P < 0.05). Compared with other nontraditional lipid parameters, regardless of adjusting for potential confounding factors, AIP had a greater OR value in ICAS (OR = 4.226, 95% CI: 1.681–10.625), ECAS (OR = 2.993, 95% CI: 1.119–8.003) and IECAS (OR = 4.502, 95% CI: 1.613–12.561). ROC curve analysis revealed that nontraditional lipid parameters had good predictive power for intracranial or extracranial atherosclerotic stenosis.ConclusionsThis Chinese hospital-based study demonstrates that nontraditional lipid parameters (AIP, LCI, RC, CRI-II, AC, CRI-I and non-HDL-C) are effective predictors of intracranial and extracranial atherosclerotic stenosis, of which AIP may be a significant risk factor for predicting atherosclerotic arterial stenosis in the intracranial or extracranial regions.

Potential role of bolus-tracking data of carotid CT angiography for atrial fibrillation prediction.

Atrial fibrillation (AF), a significant cause of ischemic stroke, often goes undetected because of its asymptomatic nature. This study investigated whether the total bolus-tracking time (TTT) and average slope (AS) of a bolus-tracking graph could be used to predict AF. This single-center, retrospective study included patients who underwent carotid CTA and a 24-h Holter test. TTT and the average degree of enhancement during bolus-tracking, derived from carotid CTA, were defined as variables of interest. All patients underwent transthoracic echocardiography. Left ventricular diastolic dysfunction and elevated left atrial pressure (LAP) were identified according to the guidelines of the 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging. The final cohort comprised 716 patients, 80 of whom presented with AF. The TTT of the AF group was significantly longer (23.8 ± 5.2 s) than that of the non-AF group (18.7 ± 2.8 s); p < 0.001. The AS of the bolus-tracking graph of the AF group was 0.80 ± 0.24, which was significantly lower than that of the non-AF group 1.38 ± 0.21 (p < 0.001). TTT was associated with a significantly higher risk of AF (odds ratio [OR]: 1.36; p < 0.001) and elevated LAP (OR: 1.46; p < 0.001). In contrast, the AS of the bolus-tracking graph was not significantly associated with either AF or an elevated LAP. TTT derived from bolus-tracking carotid CTA is an effective adjuvant tool for detecting AF related to left ventricular diastolic dysfunction and elevated LAP, confirmed using echocardiography. • Atrial fibrillation is not only a significant cause of ischemic stroke but is also often masked because of its atypical and asymptomatic features. • The total tracking time, derived from bolus tracking of carotid computed tomography angiography, may be an effective adjuvant tool for detecting undiagnosed atrial fibrillation and elevated left atrial pressure in patients.

Abstract 351: Orbital Ischemia Syndrome In A Patient With Carotid Artery Dissection

Introduction: Orbital ischemia syndrome is a very rare presentation of ocular ischemic syndrome. The cause is usually vascular pathology in the carotid artery, most often on the basis of atherosclerosis or, more rarely, dissection of the carotid artery. Our aim is to draw attention in the form of a case report to an unusual clinical manifestation of carotid artery dissection. Methods: The case report deals with a patient (male, 49 years old) who suffered from intense pain behind the right eye. After a few days of pain, he arrives at the emergency room, where he was sent by a neurologist to the CTA. Preocclusive dissection of the right carotid artery was diagnosed. Neurosonological examination shows a massive reverse flow in the right ophthalmic artery. The pain behind the eye was so intense in the following days that opiate therapy was necessary. Results: Carotid dissection was treated with anticoagulant therapy and a statin. According to the control CTA, the dissection heals at three-month intervals. Neurosonological control also shows normalization of flow in the right ophthalmic artery. The decrease in residual pain intensity even on analgesic therapy correlated with a decrease in the amplitude of retrograde flow in the ophthalmic artery. Conclusion: Painful presentation of ocular ischemic syndrome, moreover caused by carotid artery dissection, is very rare.. However, if intense periorbital pain is present, carotid artery CTA should always be performed as part of the diagnostic proces.

Potential risk factors of persistent postural-perceptual dizziness: a pilot study.

Persistent postural-perceptual dizziness (PPPD) unifies the main characteristics of chronic subjective dizziness, visual vertigo and related diseases, which is a common chronic disease in neurology. At present, the pathology of PPPD is not fully understood. In this single-center retrospective case series review, we aim to investigate the potential risk factors of PPPD. Eighty inpatients diagnosed with PPPD were recruited with 81 apparently healthy controls. Patient-specific clinico-radiological data were collected from both groups. Conditions of hypertension, diabetes, smoking, and drinking were derived from medical history. Blood test results were recorded including total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fibrinogen, vitamin B12, folic acid, total cholesterol, triglyceride, and folate level. The subjects were examined by carotid artery CTA and cranial MRI, and the imaging findings of carotid atherosclerosis (CAS), white matter hyperintensities (WMHs) and lacunar infarction (LI) were recorded. Binary logistic regression analysis was used to investigate the difference between the case and control groups. Significance was defined as p value less than 0.05. The prevalence rate of hypertension in the case group was significantly higher than that in the control group, and the detection rates of CAS, WMHs, and LI in the case group were significantly higher than those in the control group (p < 0.05 for all). Hypertension, CAS, WMHs, and LI are associated with PPPD, which may be potential risk factors for its development.

COVID-19 Stroke Apical Lung Examination Study: A Diagnostic and Prognostic Imaging Biomarker in Suspected Acute Stroke.

Diagnosis of coronavirus disease 2019 (COVID-19) relies on clinical features and reverse-transcriptase polymerase chain reaction testing, but the sensitivity is limited. Carotid CTA is a routine acute stroke investigation and includes the lung apices. We evaluated CTA as a potential COVID-19 diagnostic imaging biomarker. This was a multicenter, retrospective study (n = 225) including CTAs of patients with suspected acute stroke from 3 hyperacute stroke units (March-April 2020). We evaluated the reliability and accuracy of candidate diagnostic imaging biomarkers. Demographics, clinical features, and risk factors for COVID-19 and stroke were analyzed using univariate and multivariate statistics. Apical ground-glass opacification was present in 22.2% (50/225) of patients. Ground-glass opacification had high interrater reliability (Fleiss κ = 0.81; 95% CI, 0.68-0.95) and, compared with reverse-transcriptase polymerase chain reaction, had good diagnostic performance (sensitivity, 75% [95% CI, 56-87]; specificity, 81% [95% CI, 71-88]; OR = 11.65 [95% CI, 4.14-32.78]; P < .001) on multivariate analysis. In contrast, all other contemporaneous demographic, clinical, and imaging features available at CTA were not diagnostic for COVID-19. The presence of apical ground-glass opacification was an independent predictor of increased 30-day mortality (18.0% versus 5.7%, P = .017; hazard ratio = 3.51; 95% CI, 1.42-8.66; P = .006). We identified a simple, reliable, and accurate COVID-19 diagnostic and prognostic imaging biomarker obtained from CTA lung apices: the presence or absence of ground-glass opacification. Our findings have important implications in the management of patients presenting with suspected stroke through early identification of COVID-19 and the subsequent limitation of disease transmission.

Carotid Plaque CTA Analysis in Symptomatic Subjects with Bilateral Intraparenchymal Hemorrhage: A Preliminary Analysis.

The presence of IPH is considered the most dangerous feature because it is significantly associated with clinical ipsilateral cerebrovascular events. Our aim was to explore the characterization of plaque with CT in symptomatic subjects with bilateral intraplaque hemorrhage. Three-hundred-forty-three consecutive patients with recent anterior circulation ischemic events (<2 weeks) and CT of the carotid arteries (performed within 14 days of the cerebrovascular event) evaluated between June 2012 and September 2017 were analyzed for plaque volume composition to identify all subjects with bilateral intraplaque hemorrhage. Plaque volume was semiautomatically measured, and tissue components were classified according to the attenuation values such as the following: calcified (for values of ≥130 HU), mixed (for values of ≥60 and <130 HU), lipid (for values of ≥25 and <60 HU), and intraplaque hemorrhage (for values of <25 HU). Twenty-one subjects (15 men; mean age, 70 ± 11 years; range, 44-87 years) had bilateral intraplaque hemorrhage and were included in the analysis. Volume measurement revealed significantly larger plaques on the symptomatic side compared with the asymptomatic one (mean, 28 ± 9 versus 22 ± 8 mm, P = .007). Intraplaque hemorrhage volume and percentage were also significantly higher in the plaque ipsilateral to the cerebrovascular event (P < .001 and < .001, respectively). The volume of other plaque components did not show a statically significant association except for lipid and lipid + intraplaque hemorrhage percentages (23% versus 18% and 11% versus 15%), which were significantly different between the symptomatic and the asymptomatic sides (.016 and .011, respectively). The intraplaque hemorrhage/lipid ratio was higher on the symptomatic side (0.596 versus 0.171, P = .001). In patients with bilateral intraplaque hemorrhage and recent ischemic symptoms, the plaque ipsilateral to the symptomatic side has significantly larger volume and a higher percentage of intraplaque hemorrhage compared with the contralateral, asymptomatic side.

Clinical management of traumatic superior orbital fissure and orbital apex syndromes

ObjectivesBoth traumatic orbital apex syndrome (OAS) and traumatic superior orbital fissure syndrome (SFOS) are rare conditions after craniofacial injury. Few types of researches investigate the difference in clinical characteristics and outcome between them. We describe clinical features and cranial nerves functional recovery of traumatic OAS or SOFS and to discuss surgical decompression of these patients. Patients and MethodsA retrospective study was performed of 15 patients diagnosed with traumatic OAS and 39 patients with traumatic SOFS from July 2010 to July 2017 in our hospital. The initial status and functional recovery of cranial nerve were evaluated based on visual perception and extraocular muscle movement. The average follow-up period was 11.8 months. Results41 males’ and 13 females’ patients with a mean age of 38.3 years were included. 12 patients were diagnosed with internal carotid artery injury. In the OAS group, there is no visual recovery of those 10 totally blindness patients and only 5 functional recovery patients at 6-months follow up. No visual dysfunction occurred in the SOFS group. Cranial nerves Ⅲ, Ⅳ, and Ⅵ function recovery were better in the SOFS group than in the OAS group. ConclusionPatients with OAS might undergo more severe cranial nerves injury and worse functional recovery. Due to the occurrence of internal carotid artery injury, CTA or DSA are recommended. Surgical decompression should be considered when there is evidence of optical canal fracture or bone fragment impingement of the superior orbital fissure.

Evaluation of virtual monoenergetic imaging algorithms for dual-energy carotid and intracerebral CT angiography: Effects on image quality, artefacts and diagnostic performance for the detection of stenosis

PurposeTo investigate the impact of traditional (VMI) and noise-optimized virtual monoenergetic imaging (VMI+) algorithms on quantitative and qualitative image quality, and the assessment of stenosis in carotid and intracranial dual-energy CTA (DE-CTA). Materials and methodsDE-CTA studies of 40 patients performed on a third-generation 192-slice dual-source CT scanner were included in this retrospective study. 120-kVp image-equivalent linearly-blended, VMI and VMI+ series were reconstructed. Quantitative analysis included evaluation of contrast-to-noise ratios (CNR) of the aorta, common carotid artery, internal carotid artery, middle cerebral artery, and basilar artery. VMI and VMI+ with highest CNR, and linearly-blended series were rated qualitatively. Three radiologists assessed artefacts and suitability for evaluation at shoulder height, carotid bifurcation, siphon, and intracranial using 5-point Likert scales. Detection and grading of stenosis were performed at carotid bifurcation and siphon. ResultsHighest CNR values were observed for 40-keV VMI+ compared to 65-keV VMI and linearly-blended images (P < 0.001). Artefacts were low in all qualitatively assessed series with excellent suitability for supraaortic artery evaluation at shoulder and bifurcation height. Suitability was significantly higher in VMI+ and VMI compared to linearly-blended images for intracranial and ICA assessment (P < 0.002). VMI and VMI+ showed excellent accordance for detection and grading of stenosis at carotid bifurcation and siphon with no differences in diagnostic performance. Conclusion40-keV VMI+ showed improved quantitative image quality compared to 65-keV VMI and linearly-blended series in supraaortic DE-CTA. VMI and VMI+ provided increased suitability for carotid and intracranial artery evaluation with excellent assessment of stenosis, but did not translate into increased diagnostic performance.

Abstract TMP31: Hyperacute Extracranial Internal Carotid Artery Stenting vs Angioplasty: Which is the Best for Recanalization?

Background: Up to 20% of acute intracranial occlusions have an associated extracranial internal carotid artery (ICA) severe stenosis or occlusion, and they often need specific treatment. However, it remains unclear which is the best option for extracranial revascularization. We aimed to study differences in restenosis, complications, and stroke recurrences between patients treated with stenting and those who underwent angioplasty without stenting. Methods: Prospective study of consecutive patients with non-cardioembolic ischemic stroke and occlusion or severe stenosis of the extracranial ICA, who underwent hyperacute endovascular procedure from April 2013 to December 2015. We divided patients depending on the extracranial treatment they received. We compared the rate of stenosis &gt;50% or occlusion of the ICA at 24 hours (evaluated by carotid ultrasound or CTA). Besides, we analyzed differences in complications and stroke recurrences within 1 year of follow-up. Results: From 97 patients who underwent hyperacute revascularization of the extracranial ICA, 63 fulfilled the inclusion criteria: mean age 65.6±13.6 years, median time from symptoms onset to treatment 249 [161-330] minutes. Thirty-one (49.2%) were treated with angioplasty and 32 (50.8%) with stent. Both groups were comparable in demographic data, vascular risk factors, previous treatment (including antiplatelets), and ASPECTS score. Thirty-seven (58.7%) received intravenous rtPA and 58 (92.1%) intracranial thrombectomy. Patients who underwent angioplasty presented stenosis &gt;50% or occlusion at 24h more frequently than those who underwent stenting (67.7% vs 21.9% , p =0.002), regardless the degree of residual stenosis after the angioplasty. Thirteen (38.1%) of the angioplasties were permeable at 24 hours, nevertheless 39.1% needed a deferred stenting. There were no differences in complications, including intracranial hemorrhage, despite intravenous rtPA or early double antiplatelet therapy, as well as in stroke recurrences within 1 year ( p &gt;0.05 for all comparisons). Conclusions: Hyperacute extracranial ICA stenting seems to have a lower risk of restenosis compared to angioplasty, without a significant increase of complications and stroke recurrences

Prediction of Carotid Intraplaque Hemorrhage Using Adventitial Calcification and Plaque Thickness on CTA.

Carotid intraplaque hemorrhage is associated with stroke, plaque thickness, stenosis, ulceration, and adventitial inflammation. Conflicting data exist on whether calcification is a marker of plaque instability, and no data exist on adventitial calcification. Our goal was to determine whether adventitial calcification and soft plaque (a rim sign) help predict carotid intraplaque hemorrhage. This was a retrospective cohort study of 96 patients who underwent carotid MRA and CTA within 1 month, from 2009 to 2016. We excluded occlusions (n = 4) and near occlusions (n = 0), leaving 188 carotid arteries. Intraplaque hemorrhage was detected by using MPRAGE. Calcification, adventitial pattern, stenosis, maximum plaque thickness (total, soft, and hard), ulceration, and intraluminal thrombus on CTA were recorded. Atherosclerosis risk factors and medications were recorded. We used mixed-effects multivariable Poisson regression, accounting for 2 vessels per patient. For the final model, backward elimination was used with a threshold of P < .10. Receiver operating characteristic analysis determined intraplaque hemorrhage by using the area under the curve. Our final model included the rim sign (prevalence ratio = 11.9, P < .001) and maximum soft-plaque thickness (prevalence ratio = 1.2, P = .06). This model had excellent intraplaque hemorrhage prediction (area under the curve = 0.94), outperforming the rim sign, maximum soft-plaque thickness, NASCET stenosis, and ulceration (area under the curve = 0.88, 0.86, 0.77, and 0.63, respectively; P < .001). Addition of the rim sign performed better than each marker alone, including maximum soft-plaque thickness (area under the curve = 0.94 versus 0.86, P < .001), NASCET stenosis (area under the curve = 0.90 versus 0.77, P < .001), and ulceration (area under the curve = 0.90 versus 0.63, P < .001). The CTA rim sign of adventitial calcification with internal soft plaque is highly predictive of carotid intraplaque hemorrhage.

Clinical application of gemstone spectral imaging associated with patient-based low dose of contrast medium protocol for carotid CT angiography

Objective To investigate the clinical value of gemstone spectral imaging (GSI) associated with patient-based low dose of contrast medium protocol in carotid CTA. Methods One hundred and twenty patients who were suspected with stenotic carotid artery or carotid plaque were prospectively enrolled in the study. All of them were divide into two groups by random number table. Group A (routine group): 60 were scanned with 120 kVp after the administration of moderate-concentration CM(320 mg /ml) with 5 ml/s injection velocity, Group B (low dose group): 60 were scanned with GSI which was reconstructed using 50 % ASiR after the administration of the same CM with 3 ml/s injection velocity. The contrast dose [(test bolus peak time + 2 s – 5 s) × injection velocity] was calculated. Images of the two groups were compared in terms of arterial attenuation, signal-noise-ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality (IQ) score. The value of CT dose index volume (CTDIvol), dose length product (DLP) and effective dose (ED) was recorded, respectively. Data were analyzed by using independent samples t test or Mann-Whitney U test. Results The mean attenuation, noise, SNR, CNR, subjective image quality score, contrast dose, CTDIvol, DLP and ED of routine group was (363 ± 56)HU, (13 ± 4)HU, 30 ± 10, 38±13, 3.0 score, (69 ± 13) ml, 13.61 mGy,527 mGy · cm and 3.11 mSv, respectively. The above variables of low-dose-group was (378 ± 69) HU, (9 ± 4)HU, 48 ± 19, 62 ± 24, 2.0 score, (49 ± 7) ml, 12.72 mGy, 478 mGy · cm and 2.82 mSv, respectively. The mean attenuation and subjective IQ score of carotid artery had no significant differences statistically between two groups (P>0.05), respectively. The noise, SNR, CNR, contrast dose, CTDIvol, DLP and ED had significant differences statistically between two groups (P< 0.05), respectively. Conclusion Compared with 120 kVp protocol, the use of GSI associated with patient-based low dose of contrast medium protocol in carotid CTA could provide equivalent image quality and higher SNR and CNR of carotid artery with a smaller amount of iodine and a lower radiation dose. Key words: Tomography, X-ray computed; Carotid artery; Contrast medium

Common and uncommon intracranial arterial anatomic variations in multi-detector computed tomography angiography (MDCTA). What radiologists should be aware of.

ObjectivesThe aim of this retrospective study was twofold: (1) to show the role of multi-detector computed tomography angiography (MDCTA) in the evaluation of intracranial arterial anatomic variations; (2) to highlight their clinical importance with illustrated example cases.Materials and methodsOne thousand seven hundred thirty-nine patients who underwent carotid and/or cerebral CTA using a 16-row multi-detector CT over the last 9 years were retrospectively analysed with attention to the presence of persistent carotid-basilar anastomosis and other intracranial arterial variations.ResultsAll kinds of persistent carotid-basilar anastomosis were present in our series. The most common was the presence of fetal pCom (23 %). From the other studied anatomic variants, the most common was the presence of a hypoplastic A1 segment. In all cases CTA was an excellent diagnostic tool, providing not only high-resolution angiographic images, but also details of the surrounding structures.ConclusionsThe knowledge of intracranial anatomic variations could be very important for the treatment planning of patients who need neurointervention or to explain uncommon and unexpected clinical findings. CTA can reliably provide this kind of information by depicting intracranial anatomic variations.Teaching Points• Knowledge of intracranial anatomic variations is important. • Radiologist should be aware of the intracranial anatomic variations. • Computed tomography angiography can reliably depict intracranial anatomic variations.

Low radiation dose 256-MDCT angiography of the carotid arteries: Effect of hybrid iterative reconstruction technique on noise, artifacts, and image quality

To evaluate the effect of hybrid iterative reconstruction on qualitative and quantitative parameters at low dose carotid CTA. Materials and methods44 consecutive patients were enrolled in the study. First group (n=22) was examined under 120kV 250mAs, second group (n=22) – 100kV 250mAs. CT images in first group were reconstructed only with the filtered back projection (FBP). CT data in second group were reconstructed both with FBP and three levels of hybrid iterative reconstruction algorithm (iDose). We compared quantitative and qualitative parameters among the two groups and among four different reconstructions in second group. ResultsEffective dose in 120kV and 100kV group was 7.18±1.19mSv and 4.14±1.03mSv, respectively (p<0.0001). Mean arterial attenuation was about 25% higher in second group (236.5±46HU vs. 302.6±32.7HU; p<0.0001). Image noise at the level of humeral belt was 32.5±12.5 in 100kV group and 26.3±13.3 in 120kV (p=0.115).Average noise decreased when using 3 levels of iDose up to 23.6±6.4, 17.7±5.6 and 13.7±5.1, respectively (p=0.00001). Mean CNR increased to 10.38±3.87, 14.5±5.21 and 18.32±8.61, respectively (p<0.05).The presence of artifacts on the level of humeral belt in 120kV group was 14%, in 100kV – 41% (p=0.002). The difference in visual scores between standard and low-dose protocol was significant (p=0.008). When applying iterative reconstruction the frequency of streak artifacts decreased dramatically (p<0.0001). Most studies had excellent quality with no artifacts while using highest level of iDose. ConclusionAccording to the results of our study low dose CT angiography using hybrid iterative reconstruction may provide sufficient image quality and allows for significant reduction of patient dose.

Carotid CTA: Radiation Exposure and Image Quality with the Use of Attenuation-Based, Automated Kilovolt Selection

CTA is considered the imaging modality of choice in evaluating the supraaortic vessels in many institutions, but radiation exposure remains a matter of concern. The objective of the study was to evaluate a fully automated, attenuation-based kilovolt selection algorithm in carotid CTA in respect to radiation dose and image quality compared with a standard 120-kV protocol. Ninety-eight patients were included: 53 examinations (patient age, 66 ± 12 years) were performed by use of automated adaption of tube potential (80-140 kV) on the basis of the attenuation profile of the scout scan (study group), and 45 examinations (patient age, 67 ± 11 years) were performed by use of a standard 120-kV protocol (control group). CT dose index volume and dose-length product were recorded from the examination protocol. Image quality was assessed by ROI measurements and calculations of SNR and contrast-to-noise ratio. Subjective image quality was evaluated by 2 observers with the use of a 4-point scale (3, excellent; 0, not diagnostic). Subjective image quality was rated as "excellent" or "good" in all examinations (study group, 2.8; control group, 2.8). The algorithm automatically selected 100 kV in 47% and 80 kV in 34%; 120 kV was retained in 19%. An elevation to 140 kV did not occur. Compared with the control group, overall CT dose index volume reduction was 33.7%; overall dose-length product reduction was 31.5%. In the low-kilovolt scans, image noise and mean attenuation of ROIs inside the carotid arteries were significantly higher than in 120-kV scans, resulting in a constant or increased (80-kV group) contrast-to-noise ratio. The attenuation-based, kilovolt selection algorithm enables a dose reduction of >30% in carotid artery CTA while maintaining contrast-to-noise ratio and subjective image quality at adequate levels.

CTA for Screening of Complicated Atherosclerotic Carotid Plaque—American Heart Association Type VI Lesions as Defined by MRI

High-resolution carotid MR imaging can accurately identify complicated American Heart Association lesion type VI plaques, which are characterized by thrombus, hemorrhage, or a ruptured fibrous cap. The purpose of this study is to evaluate whether CTA can be used as screening tool to predict the presence or absence of American Heart Association lesion type VI plaques as defined by high-resolution MR imaging. Fifty-one patients with suspected ischemic stroke or TIA with carotid CTA and carotid MR imaging performed within 14 days of the event/admission from April 2008 to December 2010 were reviewed. Vessels with stents or occlusion were excluded (n = 2). Each carotid artery was assigned an American Heart Association lesion type classification by MR imaging. The maximum wall thickness, maximum soft plaque component thickness, maximum calcified component thickness, and its attenuation (if the soft plaque component thickness was >2 mm) were obtained from the CTA. The maximum soft plaque component thickness proved the best discriminating factor to predict a complicated plaque by MR imaging, with a receiver operating characteristic area under the curve of 0.89. The optimal sensitivity and specificity for detection of complicated plaque by MR imaging was achieved with a soft plaque component thickness threshold of 4.4 mm (sensitivity, 0.65; specificity, 0.94; positive predictive value, 0.75; and negative predictive value, 0.9). No complicated plaque had a soft tissue plaque thickness <2.2 mm (negative predictive value, 1) and no simple (noncomplicated) plaque had a thickness >5.6 mm (positive predictive value, 1). Maximum soft plaque component thickness as measured by carotid CTA is a reliable indicator of a complicated plaque, with a threshold of 2.2 mm representing little to no probability of a complicated American Heart Association lesion type VI plaque.

Abstract TP219: Implantation With Reveal XT After Cryptogenic Stroke Is A Useful Tool To Detect Previously Undiagnosed Atrial Fibrillation

Cryptogenic strokes are those ischemic cerebral events with no clear etiology, many of which have embolic characteristics. It is hypothesized that many of these emboli are due to undiagnosed and asymptomatic atrial fibrillation (AF). 1 Our study selected patients with cryptogenic strokes for implantation with the Reveal XT insertable cardiac monitor with the hope of detecting AF in these patients. Methods: Patients with ischemic strokes had MRI or CT performed to visualize the infarct. A neurologist determined as to whether the infarct was lacunar, and due to small vessel disease, or if it was an embolic appearing stroke based on the infarct’s size and location (cortical, wedge shaped infarct, multiple vascular territories, watershed territory). If the infarct appeared embolic, and the patient had no history of AF, a full stroke workup was initiated consisting of fasting lipid panel, bilateral carotid dopplers, MRA or CTA of the head, Transesophageal Echocardiogram (TEE), continuous telemetry and hypercoagualable labs if age of the patient was &lt;50). If the stroke was in the posterior circulation, a CTA or MRA of the neck replaced the bilateral carotid dopplers. Patients who had an embolic appearing stroke with a negative TEE, no episodes of AF on cardiac telemetry, MRA or CTA negative for a focal area of stenosis, and carotid Doppler examinations showing less than 50% ipsilateral stenosis were diagnosed as having a cryptogenic stroke. These patients were then offered implantation with the Reveal XT with follow up by a cardiac electrophysiologist who would adjudicate any triggered episodes of atrial fibrillation. Results: Following this protocol, 22 patients were successfully implanted with the Reveal XT device. Of these patients, 9 were discovered to have AF, or 41% yield. Once diagnosed with atrial fibrillation, these patients were then placed on appropriate anticoagulation therapy. Conclusion: Based on the above results, the Reveal XT insertable cardiac monitor is useful in detecting AF in patients with embolic appearing cryptogenic strokes with otherwise negative workup, and can ultimately change the patient’s therapeutic regimen. Footnotes 1 Finsterer J, (June, 2010) “Management of Cryptogenic Stroke” Acta Neurol Belg . 110(2):135–47.

Low dose 256-slice spiral CT of coronary combined with carotid and cerebrovascular angiography

Objective To investigate image quality and radiation dose of prospective ECG-gated coronary combined with carotid and cerebrovascular angiography and compare it with common coronary CTA and carotid-cerebrovascular CTA at a 256-slice spiral CT.Methods Fifty-seven patients were included in the study.The data was analyzed retrospectively and divided into 3 groups.Group 1 underwent coronary combined with carotid CTA ( n =17 ),which included a wide range of prospective ECG-gated coronary,carotid and cerebral vascular one-stop angiography.Group 2 underwent coronary CTA ( n =20),which was routine prospective ECG-gated coronary angiography.Group 3 underwent routine carotid and cerebrovascular CTA (n =20).Mean CT image attenuation and image noise were measured in the ascending aorta root,proximal parts of the bilateral common carotid artery and vertebral artery,and in the internal carotid artery at sellae level in the axial plane.Coronary artery image quality was rated using a four-point ordinal scale and carotid cerebral vascular image quality was rated using a three-point ordinal scale.Radiation dose were calculated.Mean CT image attenuation,image noise and radiation dose were compared among the 3 groups using t test.Using Mann-Whitney U,the coronary artery imaging quality was compared between group 1 and 2,and image quality of cerebral vessels was compared between group 1 and 3.Results Mean CT image attenuation [ (427 ±50) HU in group 1 and (426 ±86) HU in group 2] and image noise of the ascending aorta root [ (30 ± 9) HU in group 1 and (31 ± 9) HU in group 2 ] showed no statistical difference between group 1 and 2 (t =0.058,-0.325,P ＞0.05).There were no non-diagnosis coronary segments in group 1 and 2.And coronary segments with excellent or good image quality reached 98.1％ (202/206) in group 1 and 99.6％ ( 244/245 ) in group 2.It showed no significant difference between group 1 and 2 ( Z =-0.572,P ＞ 0.05 ).There were significant differences of mean CT image attenuation in the common carotid artery between group 1 [ ( 474 ± 70 ) HU ] and group 3 [ ( 348 ± 81 ) HU ],and in the vertebral artery between group 1 [(447 ±83)HU] and group 3 [(328 +66) HU] (t =5.043,4.869,P＜0.05).However,there was no significant difference of mean CT image attenuation in the internal carotid artery [ (370 ± 92) HU in group 1 and ( 367 ± 97 ) HU in group 3 ] ( t =0.111,P ＞ 0.05 ).There was a significant difference of image quality scores of carotid and cerebrovascular arteries between group 1 and 3 (Z =- 3.306,P ＜ 0.05 ).Effective radiation dose of groups 1,2,3 were ( 7.0 ± 0.8 ),( 3.1 ± 0.4 ) and (5.0 ± 0.3) mSv respectively.Conclusion The prospective ECG-gated coronary combined with carotid and cerebrovascular angiography is able to obtain diagnostic image quality of coronary,carotid and cerebral vascular at the 256-slice spiral CT.It is a simple,fast,noninvasive way to assess coronary and carotid cerebrovascular arteries,with advantages of less contrast medium and low radiation dose. Key words: Tomography, X-ray computed; Coronary vessels; Cerebrovascular circulation

Carotid stenosis evaluation by 64-slice CTA: comparison of NASCET, ECST and CC grading methods

Purpose is to evaluate the intraobserver and interobserver variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET), European Carotid Surgery Trial (ECST) and Common Carotid (CC) methods, which are used to measure the degree of ICA stenosis, using 64-slice CT angiography and to compare the measurements made by these three methods. 88 cases (111 carotid arteries) were included in the study. Carotid CTA was performed by a 64 slice scanner (Toshiba, Aqullion 64).Two radiologists measured the degree of carotid stenosis by using NASCET, ECST and CC methods. Intraobserver and interobserver variability of each method was determined by intraclass correlation coefficient (ICC), Bland-Altman plots and kappa and linear weighted kappa statistics. The relation between the measurements was assessed by correlation coefficient (with linear and quadratic methods). Correlation coefficients showed that there is linear correlation between the measurements made by the three methods. The degree of stenosis measured with the NASCET method had the lowest value, while the corresponding values measured with the ECST and CC methods were close to each other. ICC and Bland-Altman plots showed high intra and inter observer agreement for NASCET, ECST and CC methods whereas kappa statistics showed moderate to substantial agreement. CC method had slightly higher agreement when compared with the other two methods. Intra and interobserver agreement is high for NASCET, ECST and CC methods however CC method has a slightly higher reproducibility. There is linear correlation between the measurements made by the three methods.