Computational Fluid Dynamics of Carotid Arteries After Carotid Endarterectomy or Carotid Artery Stenting Based on Postoperative Patient-Specific Computed Tomography Angiography and Ultrasound Flow Data

Neurosurgery ◽  
2011 ◽  
Vol 68 (4) ◽  
pp. 1096-1101 ◽  
Author(s):  
Hitoshi Hayase ◽  
Koji Tokunaga ◽  
Toshio Nakayama ◽  
Kenji Sugiu ◽  
Ayumi Nishida ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computed Tomography ◽  
Computational Fluid Dynamics ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Carotid Arteries ◽  
Internal Carotid ◽  
Patient Specific ◽  
Flow Data ◽  
Simulation Results

Abstract BACKGROUND: There are significant differences in the postoperative morphological and hemodynamic conditions of the carotid arteries between carotid artery stenting (CAS) and endarterectomy (CEA). OBJECTIVE: To compare the postoperative rheological conditions after CAS with those after CEA with patch angioplasty (patch CEA) through the use of computational fluid dynamics (CFD) based on patient-specific data. METHODS: The rheological conditions in the carotid arteries were simulated in 2 patients after CAS and in 2 patients after patch CEA by CFD calculations. Three-dimensional reconstruction of the carotid arteries was performed with the images obtained with computed tomography angiography. The streamlines and wall shear stress (WSS) were calculated by a supercomputer. Adequate boundary conditions were determined by comparing the simulation results with ultrasound flow data. RESULTS: CFD was successfully calculated for all patients. The differences between the flow velocities of ultrasound data and those of the simulation results were limited. In the streamline analysis, the maximum flow velocities in the internal carotid artery after patch CEA were around two-thirds of those after CAS. Rotational slow flow was observed in the internal carotid artery bulb after patch CEA. WSS analysis found regional low WSS near the outer wall of the bulb. High WSS was observed at the distal end of the arteriotomy after patch CEA and at the residual stenosis after CAS. CONCLUSION: CFD of postoperative carotid arteries disclosed the differences in streamlines and WSS between CAS and patch CEA. CFD may allow us to obtain adequate rheological conditions conducive to achieving the best clinical results.

How patient-specific do internal carotid artery inflow rates need to be for computational fluid dynamics of cerebral aneurysms?

2020 ◽  
pp. neurintsurg-2020-015993 ◽  
Author(s):  
Mehdi Najafi ◽  
Nicole M Cancelliere ◽  
Olivier Brina ◽  
Pierre Bouillot ◽  
Maria I Vargas ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Spectral Power ◽  
Cerebral Aneurysms ◽  
Patient Specific ◽  
Perfect Agreement ◽  
The Impact

BackgroundComputational fluid dynamics (CFD) has become a popular tool for studying ‘patient-specific’ blood flow dynamics in cerebral aneurysms; however, rarely are the inflow boundary conditions patient-specific. We aimed to test the impact of widespread reliance on generalized inflow rates.MethodsInternal carotid artery (ICA) flow rates were measured via 2D cine phase-contrast MRI for 24 patients scheduled for endovascular therapy of an ICA aneurysm. CFD models were constructed from 3D rotational angiography, and pulsatile inflow rates imposed as measured by MRI or estimated using an average older-adult ICA flow waveform shape scaled by a cycle-average flow rate (Qavg) derived from the patient’s ICA cross-sectional area via an assumed inlet velocity.ResultsThere was good overall qualitative agreement in the magnitudes and spatial distributions of time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and spectral power index (SPI) using generalized versus patient-specific inflows. Sac-averaged quantities showed moderate to good correlations: R2=0.54 (TAWSS), 0.80 (OSI), and 0.68 (SPI). Using patient-specific Qavg to scale the generalized waveform shape resulted in near-perfect agreement for TAWSS, and reduced bias, but not scatter, for SPI. Patient-specific waveform had an impact only on OSI correlations, which improved to R2=0.93.ConclusionsAneurysm CFD demonstrates the ability to stratify cases by nominal hemodynamic ‘risk’ factors when employing an age- and vascular-territory-specific recipe for generalized inflow rates. Qavg has a greater influence than waveform shape, suggesting some improvement could be achieved by including measurement of patient-specific Qavg into aneurysm imaging protocols.

Clinical Significance of Conversion From Computational Fluid Dynamics to Morphology for Risk Evaluation of Aneurysm Recurrence After Coiling

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Kouichi Misaki ◽  
Iku Nambu ◽  
Takehiro Uno ◽  
Akifumi Yoshikawa ◽  
Naoyuki Uchiyama ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Pressure Difference ◽  
Risk Evaluation ◽  
Internal Carotid ◽  
Critical Role ◽  
Parent Artery ◽  
Characteristic Analysis

Abstract INTRODUCTION Hemodynamic factors play a critical role in the recurrence of intracranial aneurysms after coiling. However, the computational fluid dynamics (CFD) analyses are not consistently performed all over the world, and its benefits were limited in the specific institutes. We tried to convert the hemodynamic parameters to morphological factors for the risk evaluation of aneurysm recurrence after coiling. METHODS Using pretreatment 3-dimensional rotational angiography data of 50 internal carotid artery aneurysms (7 recanalized, 43 stable) treated with endovascular coiling, we created a virtual post-coiling model produced by cutting the aneurysm dome for construction of virtual coil plane. At the virtual coil plane, we evaluated the pressure difference, which was defined as the pressure elevation at the coil plane from the parent artery divided by the dynamic pressure at the parent artery. After a statistical analysis of the relationship between the pressure difference and aneurysm recurrence, we performed statistical comparisons of pressure difference with morphological factors. RESULTS Recanalized aneurysms showed a significantly higher pressure difference than stable aneurysms (P < .001). The receiver operating characteristic analysis showed that the area under the curve value for the pressure difference (0.967). Morphologically, all 5 aneurysms that had the virtual coil plane at the line of upper border of internal carotid artery had a significantly higher pressure difference (P < .001) and recurred after coiling (P < .001). CONCLUSION The pressure difference in the virtual post-coiling model had a strong association with aneurysm recurrence after coiling. Additionally, the location of the coil plane as a morphological factor was significantly associated with pressure difference and aneurysm recurrence. The conversion of hemodynamic factors into simple morphological factors may contribute to expanded applications of the CFD analysis.

Computational Fluid Dynamics to Evaluate the Management of a Giant Internal Carotid Artery Aneurysm

2015 ◽  
Vol 83 (6) ◽  
pp. 1057-1065 ◽  
Author(s):  
Jonathan Russin ◽  
Haithem Babiker ◽  
Justin Ryan ◽  
Leonardo Rangel-Castilla ◽  
David Frakes ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Artery Aneurysm ◽  
Carotid Artery Aneurysm ◽  
Internal Carotid Artery Aneurysm

Developmental Anatomy of the Eustachian Tube: Implications for Balloon Dilation

2021 ◽  
pp. 019459982199481
Author(s):  
Isabelle Magro ◽  
David Pastel ◽  
Jace Hilton ◽  
Mia Miller ◽  
James Saunders ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Eustachian Tube ◽  
Internal Carotid ◽  
Tertiary Care ◽  
Balloon Dilation ◽  
Care Hospital ◽  
Developmental Anatomy ◽  
Nasal Floor

Objective To describe the developmental anatomy of the eustachian tube (ET) and its relationship to surrounding structures on computed tomography. Study Design Case series with chart review. Setting A tertiary care hospital. Methods ET anatomy was assessed with reformatted high-resolution computed tomography scans from 2010 to 2018. Scans (n = 78) were randomly selected from the following age groups: <4, 5 to 7, 8 to 18, and >18 years. The following were measured and compared between groups: ET length, angles, and relationship between its bony cartilaginous junction and the internal carotid artery and between its nasopharyngeal opening and the nasal floor. Results The distance between the bony cartilaginous junction and internal carotid artery decreased with age between the <4-year-olds (2.4 ± 0.6 mm) and the 5- to 7-year-olds (2.0 ± 0.3 mm, P = .001). The ET length increased among the <4-year-olds (32 mm), 5- to 7-year-olds (36 mm), and 8- to 18-year-olds (41 mm, P < .0001). The cartilaginous ET increased among the <4-year-olds (20 mm), 5- to 7-year-olds (25 mm), and 8- to 18-year-olds (28 mm, P < .0001). The ET horizontal angle increased among the <4-year-olds (17°), 5- to 7-year-olds (21°), and 8- to 18-year-olds (23°, P≤ .003), but the ET sagittal angle did not statistically change after 5 years of age. The height difference between the nasopharyngeal opening of the ET and the nasal floor increased among the <4-year-olds (4 mm), 5- to 7-year-olds (7 mm), and 8- to 18-year-olds (11 mm, P < .0001). Conclusion The ET elongates with age, and its angles and relationship to the nasal floor increase. Although some parameters mature faster, more than half of the ET growth occurs by 8 years of age, and adult morphology is achieved by early adolescence.

Carotid Duplex Velocity Criteria Revisited for the Diagnosis of Carotid In-Stent Restenosis

Vascular ◽  
2007 ◽  
Vol 15 (3) ◽  
pp. 119-125 ◽  
Author(s):  
Ali F. AbuRahma ◽  
Damian Maxwell ◽  
Kris Eads ◽  
Sarah K. Flaherty ◽  
Tabitha Stutler
Keyword(s):  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Ct Angiography ◽  
Carotid Arteries ◽  
Internal Carotid ◽  
Carotid Angiography ◽  
Residual Stenosis ◽  
Stent Restenosis ◽  
The Mean ◽  
In Stent Restenosis

Carotid percutaneous transluminal angioplasty/stenting has become an accepted treatment modality for carotid artery stenosis in high-risk patients. There has been an ongoing debate regarding which duplex ultrasound (DUS) criteria to use to determine the rate of in-stent restenosis. This prospective study revisits DUS criteria for determining the rate of in-stent restenosis. In analyzing a subset of 12 patients (pilot study) who had both completion carotid angiography and DUS within 30 days, 10 patients with normal post-stenting carotid angiography (< 30% residual stenosis) had peak systolic velocities (PSVs) of the stented internal carotid artery (ICA) of ≤ 155 cm/s and two patients with ≥ 30% residual stenosis had internal carotid artery (ICA) PSVs of > 155 cm/s. Eighty-three patients who underwent carotid stenting as part of clinical trials were analyzed. All patients underwent post-stenting carotid DUS that was done at 1 month and every 6 months thereafter. PSVs and end-diastolic velocities of the ICA and common carotid artery were recorded. Patients with PSVs of the ICA of > 140 cm/s underwent carotid computed tomographic (CT) angiography. The perioperative stroke rate was 1.2%. When the old DUS velocity criteria for nonstented carotid arteries were applied, 54% of patients had ≥ 30% restenosis (PSV of > 120 cm/s), but when our new proposed DUS velocity criteria for stented arteries were applied (PSV of > 155 cm/s), 33% had ≥ 30% restenosis at a mean follow-up of 18 months ( p = .007). The mean PSVs for patients with normal stented carotid arteries based on CT angiography, were 122 cm/s versus 243 cm/s for ≥ 30% restenosis and 113 cm/s versus 230 cm/s for ≥ 30% restenosis based on our new criteria. The mean PSVs of in-stent restenosis of 30 to < 50%, 50 to < 70%, and 70 to 99%, based on CT angiography, were 205 cm/s, 264 cm/s, and 435 cm/s, respectively. Receiver operating curve analysis demonstrated that an ICA PSV of > 155 cm/s was optimal for detecting ≥ 30% in-stent restenosis, with a sensitivity of 100%, a specificity of 90%, a positive predictive value of 74%, and a negative predictive value of 100%. The currently used carotid DUS velocity criteria overestimated the incidence of in-stent restenosis. We propose new velocity criteria for the ICA PSV of > 155 cm/s to define ≥ 30% in-stent restenosis.

Role of magnetic resonance imaging in evaluating sphenoid sinus and internal carotid artery

2009 ◽  
Vol 123 (12) ◽  
pp. 1331-1337 ◽  
Author(s):  
H G Hatipoglu ◽  
M A Cetin ◽  
A Selvi ◽  
E Yuksel
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Sphenoid Sinus ◽  
Carotid Arteries ◽  
Internal Carotid ◽  
Minimal Distance ◽  
Resonance Imaging ◽  
Internal Carotid Arteries

AbstractObjective:This study aimed to determine whether magnetic resonance imaging has a role in the evaluation of the sphenoid sinus and internal carotid artery. In addition, we aimed to establish reference measurements for the minimal distance between the internal carotid arteries.Method:The sphenoid sinuses and neighbouring internal carotid arteries of 90 patients were evaluated using sagittal T1-weighted and axial and coronal T2-weighted magnetic resonance images.Results:Sphenoid sinus pneumatisation was categorised as occipitosphenoidal (0 per cent), conchal (3.3 per cent), presellar (14.4 per cent) or sellar (82.2 per cent). The internal carotid artery protruded into the sphenoid sinus in 32.8 per cent, with a septum in 9.4 per cent. The incidence of sellar-type sphenoid sinus pneumatisation was higher in patients with protrusion of the internal carotid artery into the sphenoid sinus (p < 0.001). The incidence of presellar pneumatisation was higher in patients without internal carotid artery protrusion (p < 0.001). The minimal distance between the internal carotid arteries varied between 9.04 and 24.26 mm (mean, 15.94 mm).Conclusion:Magnetic resonance imaging can provide useful information about the sphenoid sinus and internal carotid artery, prior to endoscopic sphenoidotomy and trans-sphenoidal hypophysectomy.

scholarly journals Elective reconstruction of thoracoabdominal aortic aneurysm type IV by transabdominal approach

2012 ◽  
Vol 69 (1) ◽  
pp. 90-93
Author(s):  
Ivan Marjanovic ◽  
Miodrag Jevtic ◽  
Sidor Misovic ◽  
Momir Sarac
Keyword(s):  
Computed Tomography ◽  
Aortic Aneurysm ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Thoracoabdominal Aortic Aneurysm ◽  
Aortic Dilatation ◽  
Aortic Reconstruction ◽  
Transabdominal Approach ◽  
Type Iv

Introduction. Thoracoabdominal aortic aneurysm (TAAA) type IV represents an aortic dilatation from the level of the diaphragmatic hiatus to the iliac arteries branches, including visceral branches of the aorta. In the traditional procedure of TAAA type IV repair, the body is opened using thoractomy and laparotomy in order to provide adequate exposure of the descending thoracic and abdominal aorta for safe aortic reconstruction. Case report. We reported a 71-yearold man with elective reconstruction of the TAAA type IV performed by transabdominal approach. Computed tomography scans angiography revealed a TAAA type IV with diameter of 62 mm in the region of celiac trunk and superior mesenteric artery branching, and the largest diameter of 75 mm in the infrarenal aortic level. The patient comorbidity included a chronic obstructive pulmonary disease and hypertension, therefore he was treated for a prolonged period. In preparation for the planned aortic reconstruction asymptomatic carotid disease (occlusion of the left internal carotid artery and subtotal stenosis of the right internal carotid artery) was diagnosed. Within the same intervention percutaneous transluminal angioplasty with stent placement in right internal carotid artery was made. In general, under endotracheal anesthesia and epidural analgesia, with transabdominal approach performed aortic reconstruction with tubular dakron graft 24 mm were, and reimplantation of visceral aortic branches into the graft performed. Postoperative course was uneventful, and the patient was discharged on the postoperative day 17. Control computed tomography scan angiography performed three months after the operation showed vascular state of the patient to be in order. Conclusion. Complete transabdominal approach to TAAA type IV represents an appropriate substitute for thoracoabdominal approach, without compromising safety of the patient. This approach is less traumatic, especially in patients with impaired pulmonary function, because there is no thoracotomy and any complications that could follow this approach.

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