Subjective and objective evaluation of image quality in biplane cerebral digital subtraction angiography following significant acquisition dose reduction in a clinical setting.

OBJECTIVE: Different technical and procedural methods have been introduced to develop low radiation dose protocols in neurointerventional examinations. We investigated the feasibility of minimizing radiation exposure dose by simply decreasing the detector dose during cerebral DSA and evaluated the comparative level of image quality using both subjective and objective methods. METHODS: In a prospective study of patients undergoing diagnostic cerebral DSA, randomly selected vertebral arteries (VA) and/or internal carotid arteries and their contralateral equivalent arteries were injected. Detector dose of 3.6 and 1.2 µGy/frame were selected to acquire standard dose (SD) and low dose (LD) images, respectively. Subjective image quality assessment was performed by two neurointerventionalists using a 5 point scale. For objective image quality evaluation, circle of Willis vessels were categorized into conducting, primary, secondary, and side branch vessels. Two blinded observers performed arterial diameter measurements in each category. Only image series obtained from VA injections opacifying the identical posterior intracranial circulation were utilized for objective assessment. RESULTS: No significant difference between SD and LD images was observed in subjective and objective image quality assessment in 22 image series obtained from 10 patients. Mean reference air kerma and kerma area product were significantly reduced by 61.28% and 61.24% in the LD protocol, respectively. CONCLUSIONS: Our study highlights the necessity for reconsidering radiation dose protocols in neurointerventional procedures, especially at the level of baseline factory settings.

Altered aortic shape in bicuspid aortic valve relatives influences blood flow patterns.

AIMS: Bicuspid aortic valve (BAV) is known to exhibit familial inheritance and is associated with aortopathy and altered aortic haemodynamics. However, it remains unclear whether BAV-related aortopathy can be inherited independently of valve morphology. METHODS AND RESULTS: Four-dimensional flow magnetic resonance imaging for the in vivo assessment of thoracic aortic 3D blood flow was performed in 24 BAV relatives with trileaflet aortic valves (age = 40 ± 14 years) and 15 healthy controls (age = 37 ± 10 years). Data analysis included aortic dimensions, shape (round/gothic/cubic), and 3D blood flow characteristics (semi-quantitative vortex/helix grading and peak velocities). Cubic and gothic aortic shapes were markedly more prevalent in BAV relatives compared with controls (38 vs. 7%). Ascending aorta (AAo) vortex flow in BAV relatives was significantly increased compared with controls (grading = 1.5 ± 1.0 vs. 0.6 ± 0.9, P = 0.015). Aortic haemodynamics were influenced by aortic shape: peak velocities were reduced for gothic aortas vs. round aortas (P = 0.003); vortex flow was increased for cubic aortas in the AAo (P < 0.001) and aortic arch (P = 0.004); vortex and helix flows were elevated for gothic aortas in the AAo and descending aorta (P = 0.003, P = 0.029). Logistic regression demonstrated significant associations of shape with severity of vortex flow in AAo (P < 0.001) and aortic arch (P = 0.016) in BAV relatives. CONCLUSION: BAV relatives expressed altered aortic shape and increased vortex flow despite the absence of valvular disease or aortic dilatation. These data suggest a heritable component of BAV-related aortopathy affecting aortic shape and aberrant blood flow, independent of valve morphology.

Familial incidence of the congenital torcular dural arteriovenous shunt: Case report and review of the literature.

Congenital dural sinus malformations are rare but can be major causes of mortality and morbidity in the pediatric population if not detected and managed urgently. Lesions involving large draining sinus structures such as superior sagittal sinus and torcular herophili can result in significant intracranial circulation impairment mostly due to venous drainage disturbance. Early detection plays a pivotal role in the outcome of the patients. Rarely familial incidence of some types of arteriovenous malformations in isolation from other congenital hereditary disorders has been reported. Knowledge of the familial association of congenital dural sinus malformations may raise the awareness for considering the possibility of occurrence of these lesions in the relatives of index cases. Herein, we describe the occurrence of giant torcular dural shunt in two pediatric cousins treated with endovascular embolization.

Focal stenosis of the sigmoid sinus causing intracranial venous hypertension: Case report, endovascular management, and review of the literature.

Regardless of the underlying pathology, elevated intracranial pressure is the endpoint of any impairment in either cerebrospinal fluid (CSF) absorption (including arachnoid villi) or intracranial venous drainage. In all age groups, the predominant final common pathway for CSF drainage is the dural venous sinus system. Intracranial venous hypertension (ICVH) is an important vascular cause of intracranial hypertension (and its subsequent sequelae), which has often been ignored due to excessive attention to the arterial system and, specifically, arteriovenous shunts. Various anatomical and pathological entities have been described to cause ICVH. For the second time, we present a unique case of severe focal stenosis in the distal sigmoid sinus associated with concurrent hypoplasia of the contralateral transverse sinus causing a significant pressure gradient and intracranial hypertension, which was treated with endovascular stent placement and angioplasty.

Age-Related Changes of Normal Cerebral and Cardiac Blood Flow in Children and Adults Aged 7 Months to 61 Years.

BACKGROUND: Cerebral and cardiac blood flow are important to the pathophysiology and development of cerebro- and cardiovascular diseases. The purpose of this study was to investigate the age dependence of normal cerebral and cardiac hemodynamics in children and adults over a broad range of ages. METHODS AND RESULTS: Overall, 52 children (aged 0.6-17.2 years) and 30 adults (aged 19.2-60.7 years) without cerebro- and cardiovascular diseases were included in this study. Intracranial 4-dimensional flow and cardiac 2-dimensional phase-contrast magnetic resonance imaging were performed for all participants to measure flow parameters in the major intracranial vessels and aorta. Total cerebral blood flow (TCBF), cardiac and cerebral indexes, brain volume, and global cerebral perfusion (TCBF/brain volume) were evaluated. Flow analysis revealed that TCBF increased significantly from age 7 months to 6 years (P<0.001) and declined thereafter (P<0.001). Both cardiac and cerebral indices declined with age (P<0.001). The ratio of TCBF to ascending aortic flow declined rapidly until age 18 years (P<0.001) and remained relatively stable thereafter. Age-related changes of cerebral vascular peak velocities exhibited a trend similar to TCBF. By comparison, aortic peak velocities maintained relatively high levels in children and declined with age in adults (P<0.001). TCBF significantly correlated with brain volume in adults (P=0.005) and in 2 pediatric subgroups, aged <7 years (P<0.001) and 7 to 18 years (P=0.039). CONCLUSIONS: Cerebral and cardiac flow parameters are highly associated with age. The findings collectively highlight the importance of age-matched control data for the characterization of intracranial and cardiac hemodynamics.

Complex Alterations of Intracranial 4-Dimensional Hemodynamics in Vein of Galen Aneurysmal Malformations During Staged Endovascular Embolization.

BACKGROUND: Vein of Galen aneurysmal malformations (VGAMs) are rare congenital cerebral arteriovenous shunts often treated by staged endovascular embolization early in life. Treatment-induced changes in intracranial hemodynamics and their impact on the clinical management of VGAM patients remain unclear. OBJECTIVE: To evaluate hemodynamic alterations in the cerebral arterial and venous network in pediatric patients with VGAMs during staged embolizations. METHODS: Serial 4-dimensional flow magnetic resonance imaging (21 scans) was performed in 6 VGAM patients (3 female; mean age, 2.1 ± 4.0 years) undergoing staged embolization. Time-integrated pathlines were used to visualize 3-dimensional blood flow changes in intracranial arterial and venous systems. Total cerebral arterial inflow (flow in bilateral internal carotid arteries plus basilar artery), arteriovenous shunt flow, and blood flow in other major cerebral arteries (middle cerebral artery; posterior cerebral artery) were quantified for all patients. RESULTS: Intracranial 3-dimensional blood flow visualization demonstrated marked reduction of arteriovenous shunting and distinct hemodynamic alterations after embolization. From baseline to endpoint embolization, total cerebral arterial inflow dropped by 40.2% (from 22.70 ± 6.54 mL/s to 13.57 ± 4.87 mL/s), corresponding to arteriovenous shunt flow reduction of 73.5% (from 9.69 ± 6.16 mL/s to 2.57 ± 3.79 mL/s). In addition, the ipsilateral posterior cerebral artery/middle cerebral artery flow ratio decreased by 86.9% (from 4.20 ± 6.28 to 0.55 ± 0.23). CONCLUSION: Hemodynamic alterations in VGAMs after embolization can be visualized and quantified using 4-dimensional flow magnetic resonance imaging. Cerebral arterial inflow and arteriovenous shunt flow reduction and complex flow redistribution after embolization illustrate the potential of 4-dimensional flow magnetic resonance imaging to better evaluate the efficacy of interventions and monitor treatment effects.

Adjunctive value of intra-arterial cone beam CT angiography relative to DSA in the evaluation of cranial and spinal arteriovenous fistulas.

OBJECTIVE: To assess the adjunctive diagnostic value of intra-arterial cone-beam CT angiography (IA-CBCTA) relative to digital subtraction angiography (DSA) in the anatomic identification/localization of intracranial/spinal arteriovenous fistulas (AVFs) and utility for surgical/endovascular treatment planning. METHODS: Retrospectively, two blinded observers scored DSA and IA-CBCTA images of 32 patients with intracranial/spinal AVFs based on a qualitative scale. The following parameters were scored: arterial feeders, venous drainers and course, fistula site, and adjacent anatomic landmarks for cross-sectional localization. The total score was defined as the overall diagnostic value. Differences between IA-CBCTA and DSA scores were defined as the IA-CBCTA efficacy value. Observers described the treatment strategy at the end of DSA and IA-CBCTA grading, respectively. Mann-Whitney U test, Wilcoxon's signed rank test, and Kendall's tau (τ) coefficient were used for statistical analysis. RESULTS: Interobserver agreement of overall diagnostic value for IA-CBCTA was good (τ=0.59, p=0.001) with no significant variance between the two observers' IA-CBCTA efficacy values (p=0.2). Significantly higher scores were assigned to IA-CBCTA for overall diagnostic value (both observers: p<0.0001), delineation of fistula site (observer 1: p<0.0001, observer 2: p=0.0003), and adjacent anatomic landmarks (both observers: p<0.0001). Observers found IA-CBCTA helpful, enabling a more confident treatment approach in 30 and 29 cases for observer 1 and observer 2, respectively. Both observers altered the treatment plan in two cases based on IA-CBCTA findings. CONCLUSIONS: IA-CBCTA as an adjunctive technique to DSA improves the anatomic delineation of AVFs, particularly for the fistula site and cross-sectional localization, and has the potential to improve treatment planning.

Analysis of the thoracic aorta using a semi-automated post processing tool.

OBJECTIVE: To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gated Dual Source CT Angiogram (DSCTA). METHODS: This retrospective HIPAA compliant study was approved by our IRB. Transaxial maximum diameters of outer wall to outer wall were studied in fifty patients at seven anatomic locations of the thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta (MAA) at the level of right pulmonary artery, proximal aortic arch (PROX) immediately proximal to innominate artery, distal aortic arch (DIST) immediately distal to left subclavian artery, and descending aorta (DESC) at the level of diaphragm. Measurements were performed using a manual method and semi-automated software. All readers repeated their measurements. Inter-method, intra-observer and inter-observer agreements were evaluated according to intraclass correlation coefficient (ICC) and Bland-Altman plot. The number of cases with manual contouring or center line adjustment for the semi-automated method and also the post-processing time for each method were recorded. RESULTS: The mean difference between semi-automated and manual methods was less than 1.3mm at all seven points. Strong inter-method, inter-observer and intra-observer agreement was recorded at all levels (ICC ≥ 0.9). The maximum rate of manual adjustment of center line and contour was at the level of annulus. The average time for manual post-processing of the aorta was 19 ± 0.3 min, while it took 8.26 ± 2.1 min to do the measurements with the semi-automated tool (Vitrea version 6.0.0.1 software). The center line was edited manually at all levels, with most corrections at the level of annulus (60%), while the contour was adjusted at all levels with highest and lowest number of corrections at the levels of annulus and DESC (75% and 0.07% of the cases), respectively. CONCLUSION: Compared to the commonly used manual method, semi-automated measurement of vessel dimensions is feasible in the thoracic aorta with the advantage of reduced post-processing time.