Internal versus external biliary drainage in malignant biliary obstructions: is there a difference in the rate of infection?

BACKGROUND: Percutaneous biliary drainage is a frequently used method to provide biliary decompression in patients with biliary obstruction. PURPOSE: To investigate the between drainage type and infection risk in patients treated with internal-external and external biliary drainage catheterization for malignant biliary obstruction. MATERIAL AND METHODS: A total of 410 patients with malignant biliary obstruction who underwent internal-external or external biliary drainage catheterization between January 2012 and October 2016 were retrospectively evaluated. We investigated the correlation between percutaneous biliary drainage technique and infection frequency by evaluating patients with clinical findings, bile and blood cultures, complete blood counts, and blood biochemistry. RESULTS: There was no statistically significant difference between the selected patient groups (internal-external or external biliary drainage catheter placed) in terms of age, sex, primary diagnosis, receiving chemotherapy, catheter sizes, and outpatient-patient status. After catheterization, catheter-related infection was observed in 49 of 216 (22.7%) patients with internal-external and 18 of 127 (14.2%) patients with external biliary drainage catheters, according to the defined criteria. There was no difference in infection rate after the biliary drainage in the two groups (P > 0.05). There was also no difference concerning frequently proliferating microorganisms in bile cultures. CONCLUSION: Internal-external biliary drainage catheter placement does not bring an additional infection risk for uninfected cholestatic patients whose obstruction could be passed easily in the initial drainage.

Arterial transit artifacts observed on arterial spin labeling perfusion imaging of carotid artery stenosis patients: What are counterparts on symptomatology, dynamic susceptibility contrast perfusion, and digital subtraction angiography?

PURPOSE: To investigate possible relationships between the presence and location of arterial transit artifacts (ATA) and clinical symptoms, digital subtraction angiography (DSA), and dynamic susceptibility contrast (DSC) perfusion imaging abnormalities in patients with carotid artery stenosis (CAS). METHODS: Forty-seven patients who underwent arterial spin labeling (ASL) and DSC perfusion imaging in the same period diagnosed with > 50% unilateral internal carotid artery (ICA) stenosis by DSA performed 24 h after perfusion imaging were included. The presence of ATA, localization and hypoperfusion were evaluated using ASL interpretation. Maps derived from DSC perfusion, symptomatology, stenosis rates, and collateralization findings observed in DSA were investigated. Probable relationships were evaluated. RESULTS: ATA on ASL were detected in 68.1% (32/47); 40.6% (13/32) of ATAs were observed in the distal middle cerebral artery (MCA) trace, 50% (16/32) in the intracranial ICA and MCA traces, and 9.4% (3/32) in the intracranial ICA trace. When classifications based on the ATA presence and localization was made, qualitative and quantitative CBF, MTT, and TTP abnormalities, symptomatology, stenosis rates, and collateralization findings significantly differed between groups (p < 0.05). CONCLUSION: The presence and localization of ATA in patients with CAS may provide essential insights into cerebral hemodynamics and the CAS severity. ATAs observed only in the distal MCA trace may represent early-stage perfusion abnormalities and a moderate level of stenosis. ATA in the ICA trace may related to a more advanced level of perfusion abnormalities, critical stenosis rates, symptom or collateralization presence.

New technique: the use of the THRIVE sequence in the follow-up of patients who received endovascular intracranial aneurysm treatment.

PURPOSE: To determine the diagnostic accuracy of 3D time of flight MR angiography (TOF-MRA), contrast enhanced MR angiography (CE-MRA), and T1-weighted high-resolution isotropic volume examination (THRIVE) at 3 T for the evaluation of intracranial aneurysm occlusion after endovascular treatment and to evaluate the usability of the THRIVE sequence in endovascular treatment follow-up. METHODS: In 3 T MR follow-up examinations of 66 aneurysms in 50 patients treated endovascularly, 3D TOF-MRA (index test), THRIVE (index test), and CE-MRA (reference standard) examinations were performed in a retrospective consecutive case series. Source images were classified as class 1, class 2, and class 3 according to the Raymond criteria using MIP (maximum intensity projection) techniques. The compatibility between sequences was evaluated with the Kappa test. The sensitivity and specificity were also calculated. RESULTS: In the evaluation of THRIVE and CE-MRA sequences, compatibility was determined in 61 cases in total, with an overall fit of 61/66 (92.42%). A statistically significant correlation was found between THRIVE and CE-MRA (p < 0.001, κ = 0.800). In the evaluation of TOF and CE-MRA sequences, compatibility was determined in 54 cases in total, and the overall fit was 54/66 (81.8%). A statistically significant agreement was found between TOF and CE-MRA (p < 0.001, κ = 0.502). Assuming that CE-MRA is a reference standard, the sensitivity and specificity of the TOF sequence were 44.4% and 97.9%, respectively, and the sensitivity and specificity of the THRIVE sequence were 77.8% and 97.9%, respectively. CONCLUSION: The THRIVE sequence can be used as a noncontrast method for monitoring endovascularly treated intracranial aneurysms.

Non-contrast magnetic resonance venography with Inhance 3D Velocity: diagnostic performance for intracranial venous thrombosis.

PURPOSE: The aim of this study was to evaluate the diagnostic performance of Inhance 3D Velocity (I3DV) in intracranial venous thrombosis and investigate the possible impact of venous sinus hypoplasia/aplasia on false thrombosis diagnosis made with I3DV. METHODS: This study included 540 patients. Contrast-enhanced magnetic resonance venography combined with conventional sequences was considered the gold standard test (GST), while I3DV was considered as diagnostic test. We accessed the diagnostic success of I3DV for intracranial venous thrombosis detection, thrombosed vessel identification, and total/partial thrombus distinction. The possible relationship between false-positive thrombus diagnosed by I3DV and venous sinus hypoplasia or aplasia diagnosed by GST was investigated. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of I3DV in the detection of intracranial venous thrombosis were 95.7%, 92.1%, 64.1%, 99.3%, and 92.6%, respectively. A significant association was observed between I3DV and GST in terms of thrombosis detection and total/partial thrombus distinction (p < 0.001). A significant relationship was observed between false-positive thrombosis diagnosis in I3DV and hypoplasia in the left transverse sinus (p < 0.001). CONCLUSION: Intracranial venous thrombosis may be diagnosed faster and more accurately than traditional phase contrast magnetic resonance angiography in I3DV. This technique can be used in situations where contrast medium application is contraindicated. As in other non-contrast magnetic resonance venography techniques, left transverse sinus hypoplasia can be diagnosed as a thrombosed vessel in I3DV.

Endovascular treatment modalities for basilar artery fenestration aneurysms: experience of two centers and literature review

Background/aim: The aim of this study is to present our experience on various endovascular treatment modalities of basilar fenestration aneurysms and reviewing our findings together with literature data. Materials and methods: A total of 26 basilar artery fenestration (BAF) aneurysms in 24 patients were endovascularly treated in two different neurointerventional radiology clinics. All patients had been evaluated with computed tomography (CT), CT angiography, and digital subtraction angiography before the procedure. Results: Aneurysms of all patients were successfully occluded (technical success rate 100%). Procedure-related complications were seen in two patients. Our comprehensive literature research revealed that studies related with the topic are composed mostly of case reports. In the literature, a total of 113 BAF aneurysms of 101 patients had been treated endovascularly in 46 studies between 1993 and 2019. Success rate of the treatment was reported as 97%, clinical success rate as 91%, and complication rate as 8.8%, while these rates are 100%, 92%, and 7.6% in our study, respectively. Conclusion: Although the number of cases is low in our study, to our knowledge, it is the widest series in the literature until today. Our results demonstrate that BAF aneurysms can be treated successfully and safely with different endovascular techniques, with more stent use in recent years.

Contrast medium enhanced susceptibility imaging signal mechanism; should we use contrast medium?

BACKGROUND: Intracranial lesions exhibit clear contrast enhancement in T1-weighted imaging, but the mechanism whereby contrast-enhanced susceptibility-weighted imaging (CE-SWI) generates signals remains unclear. Contrast enhancement patterns cannot be reliably predicted. PURPOSE: To explore the mechanism of CE-SWI contrast enhancement. MATERIAL AND METHODS: Fifty-five patients were retrospectively enrolled. All of the imaging employed a clinical 3T magnetic resonance imaging (MRI) system fitted with a 32-channel head coil. Minimum-intensity projection reformatted images were evaluated. Intracranial lesions and brain parenchymal intensities were explored using SWI and CE-SWI. signal intensity rates were calculated by dividing the lesional intensity by the white matter intensity, after which the SWI and CE-SWI signal intensity rate were compared. Two observers independently performed intralesional susceptibility signal analysis. RESULTS: After contrast medium administration, malignant and extra-axial tumors exhibited obvious contrast enhancement on CE-SWI (P < 0.001 and P = 0.013, respectively). The signal intensity of white matter was significantly reduced. The signal intensity rates rose significantly in the benign, malignant, and extra-axial groups (P < 0.001). Between-radiologist agreement in terms of intralesional susceptibility signal assessment was strong (kappa = 0.8, P < 0.001). CONCLUSION: Contrast media can either reduce or increase SWI signal intensities. The dual contrast feature of CE-SWI can be useful when exploring intracranial disorders.

Susceptibility Imaging in Glial Tumor Grading; Using 3 Tesla Magnetic Resonance (MR) System and 32 Channel Head Coil.

BACKGROUND: Susceptibility weighted imaging (SWI) is a velocity compensated, high-resolution three-dimensional (3D) spoiled gradient-echo sequence that uses magnitude and filtered-phase data. SWI seems to be a valuable tool for non-invasive evaluation of central nervous system gliomas. Relative cerebral blood volume (rCBV) ratio is one of the best noninvasive methods for glioma grading. Degree of intratumoral susceptibility signal (ITSS) on SWI correlates with rCBV ratio and histopathological grade. This study investigated the effectiveness of ITSS grading and rCBV ratio in preoperative assessment. MATERIAL/METHODS: Thirty-one patients (17 males and 14 females) with histopathogical diagnosis of glial tumor undergoing routine cranial MRI, SWI, and perfusion MRI examinations between October 2011 and July 2013 were retrospectively enrolled. All examinations were performed using 3T apparatus with 32-channel head coil. We used ITSS number for SWI grading. Correlations between SWI grade, rCBV ratio, and pathological grading were evaluated. ROC analysis was performed to determine the optimal rCBV ratio to distinguish between high-grade and low-grade glial tumors. RESULTS: There was a strong positive correlation between both pathological and SWI grading. We determined the optimal rCBV ratio to discriminate between high-grade and low-grade tumors to be 2.21. CONSLUSIONS: In conclusion, perfusion MRI and SWI using 3T MR and 32-channel head coil may provide useful information for preoperative glial tumor grading. SWI can be used as an accessory to perfusion MR technique in preoperative tumor grading.

Catheter-directed ultrasound-accelerated thrombolysis may be life-saving in patients with massive pulmonary embolism after failed systemic thrombolysis.

The treatment options for high risk acute pulmonary embolism (PE) patients with failed systemic thrombolytic treatment (STT) is limited. The clinical use of catheter directed thrombolysis with the EkoSonic Endovascular System (EKOS) in this population has not been evaluated before. Catheter directed thrombolysis is an effective treatment modality for high risk PE patients with failed STT. Thirteen consecutive patients with failed STT were included in the study. EKOS catheters were placed and tissue plasminogen activator (t-PA) in combination with unfractionated heparin were given. Clinical and echocardiographic properties of the patients were collected before EKOS, at the end of EKOS and during the follow-up visit 6 months after discharge. The duration of EKOS treatment was 21.8 ± 3.8 h and the total dose of tPA was 31.2 ± 15.3 mg. One patient who presented with cardiac arrest died and the clinical status of the remaining subjects improved significantly. Any hemorrhagic complication was not observed. EKOS resulted in significant improvement of right ventricular functions and decrease of systolic pulmonary artery pressure. During a follow-up period of 6 months none of the patients died or suffered recurrent PE. In addition, echocardiographic parameters or right ventricular function significantly got better compared to in-hospital measurements. EKOS is an effective treatment modality for high risk PE patients with failed STT and can be applied with very low hemorrhagic complications.

Pattern, variability, and hemispheric differences of the subparietal sulcus on multiplanar reconstructed MR images.

PURPOSE: The aim of this study was to analyze variations in the morphological features of the subparietal sulcus (SPS) and to investigate interhemispheric and gender differences in these variations using multiplanar reconstructed (MPR) magnetic resonance (MR) images. METHODS: Two hundred subjects with normal cranial MR imaging, including high-resolution T1-weighted volumetric data, were enrolled in the study. The sagittal or oblique sagittal MPR images created from high-resolution T1-weighted data were analyzed for the following morphological features: the SPS patterns, the continuity of the SPS with the cingulate sulcus and parieto-occipital sulcus (POS), and the presence of upwardly directed SPS branches reaching to the hemispheric surface. Interindividual variability of the morphologic features, hemispheric asymmetry, and gender differences were investigated. RESULTS: Considerable variations were found in the morphological features of the SPS. The H-pattern, no connection with the cingulate sulcus or the POS, and one upwardly directed branch reaching the hemispheric surface were most commonly observed morphologic features of the SPS in 45.2, 41.8, and 48 % of the all hemispheres, respectively. Furthermore, the connection of the SPS only with the cingulate sulcus and the presence of two upwardly directed branches reaching the hemispheric surface showed the significant leftward asymmetry (P < 0.05). CONCLUSIONS: Our study demonstrated the extensive morphological variability of the SPS and the hemispheric asymmetry for some morphological features. Knowledge of these variations and their hemispheric asymmetry may be helpful for surgical approaches in neurosurgery and structure-function correlations in functional neuroimaging studies involving the posteromedial hemisphere.

Statistical shape analysis of temporal lobe in mesial temporal sclerosis patients.

BACKGROUND: Surgery is regarded as a common treatment option for patients with mesial temporal lobe epilepsy due to hippocampal sclerosis but sometimes deciding this diagnosis can be very difficult. We aim to investigate the shape differences in the temporal lobe of mesial temporal sclerosis epilepsy patients compared with healthy controls, investigating the side difference and, if present, assessing the clinical application of this situation. METHOD: The MRI scans of mesial TLE patients and controls were retrospectively reviewed. Temporal lobe data were collected from the two-dimensional digital images. Standard anthropometric landmarks were selected and marked on each digital image using TPSDIG 2.04 software. Eight anatomic landmarks were marked on images. A generalized Procrustes analysis was used to evaluate the shape difference. The shape deformation of the temporal lobe from control to patient was evaluated using the TPS method. RESULTS: There were statistically significant TL shape differences between groups. High level deformations for the left and right side from the control to patient group were seen in the TPS graphic. The highest deformation was determined at the inferior lateral temporal midpoint of the middle temporal gyri and superior temporal landmark points of both the right and left sides. CONCLUSION: Our study for the first time demonstrated temporal shape differences in TLE patients using a landmark-based geometrical morphometric method by taking into consideration the topographic distribution of TL.

Closure of the axillary artery puncture site with StarClose system after endovascular interventions.

The use of the StarClose vascular closure device for puncture site hemostasis after therapeutic endovascular interventions performed through the axillary artery under anticoagulant therapy in six patients is reported. Three minor complications, including hematoma, prolonged hemostasis, and pain, occurred in three patients. Based on this limited experience, this method can be used safely for axillary artery puncture site hemostasis after endovascular procedures without significant complications.

Massive cerebrovascular air embolism during posttraumatic cardiopulmonary resuscitation.

Air embolism is known to be a complicating factor in several clinical settings, including thoracic, cardiovascular, and neurosurgical operations; central line placement; and penetrating thoracic and cranial trauma. There are, however, only few case descriptions for cardiopulmonary resuscitation massive cerebral air embolism, and the frequency of this supposedly rare complication is unknown. Computed tomography is useful for showing cerebral air embolism. In this report, we present a 16-year-old adolescent girl with cerebrovascular air embolism on computed tomographic examination after a posttraumatic cardiopulmonary resuscitation and discuss the reasonable mechanisms of cerebrovascular air embolism.

Rapid spontaneous recovery after development of a spinal epidural hematoma: a case report.

Spontaneous spinal epidural hematoma is a very rare clinical emergency. A permanent neurological deficit or even death may result if diagnosis and treatment are delayed. Many cases can be diagnosed upon detailed neurological examination and magnetic resonance (MR) imaging. Usually, surgery is required, but rarely, the condition may improve spontaneously. A 46-year-old male patient was admitted to our emergency department because of rapidly evolving severe paraplegia following development of sudden-onset neck pain. Spinal MR imaging detected an epidural hematoma compressing the spinal cord at the C5­T1 level. Clinical and radiological follow-up showed that the patient recovered spontaneously in 48 hours without any need for surgical treatment.

Characteristics of Cerebral Venous Sinus Thrombosis Due to Autoimmune Diseases: A Single-Center Retrospective Observational Study.

OBJECTIVES: Cerebral venous sinus thrombosis (CVST) is a cerebrovascular disease characterized by thrombosis of the cerebral venous or dural sinuses. Autoimmune diseases (AD) are important causes of CVST. This study aims to reveal the differences between CVST associated with autoimmune diseases compared with other causes (OCs) and Behcet's syndrome (BS) compared with other ADs. METHODS: This is a single-center retrospective study in which the medical records of 187 patients we followed with a diagnosis of CVST between 2008 and 2023 were collected retrospectively. Four neurologists collected data on initial symptoms, neurological examinations, and laboratory findings. Findings on magnetic resonance imaging and magnetic resonance venography performed on all patients (thrombosis localizations, hemorrhagic or ischemic complications, and collateralization) were re-evaluated by 2 radiologists. The results were compared with AD, other ADs, and OCs groups. RESULTS: There were 28 cases of CVST associated with AD. Of these, 18 were BS, and 10 were other AD. Subacute-chronic onset, headache, and transverse sinus involvement were more common in AD-related patients than in OCs. However, collateralization, venous infarction, hemorrhagic transformation, and bleeding were less common. BS-related patients had earlier age, more frequent transverse sinus, less frequent cortical vein thrombosis, and better collateralization than other ADs. CONCLUSION: CVST is one of the rare complications in autoimmune diseases. It has a more subacute-chronic onset. Since headaches are more common, it is essential to make a differential diagnosis of CVST in autoimmune diseases with chronic headaches. Transverse sinus thrombosis is more common. Collateralization, venous infarction, and hemorrhagic transformation are less.

Prognostic factors of tumefactive demyelinating lesions and differential features for multiple sclerosis in etiology.

BACKGROUND: Many different pathologies may underlie tumefactive demyelinating lesions. Identifying clinical and radiologic distinguishing features before pathologic examination is essential for diagnosis and treatment. In this study, we aimed to determine the clinical and radiologic features affecting the etiology and disease course of patients with tumefactive lesions (TDL). MATERIALS AND METHODS: We included 35 clinicoradiologically or histologically diagnosed TDL patients in our center over 11 years. Patient records were retrospectively evaluated and recorded. Clinical features, cerebral neuroimaging, and histologic biopsy preparations, if any, were assessed by three independent neurologists, two neuroradiologists, and two pathologists at admission and follow-up, respectively. RESULTS: The mean age of patients with TDL was 40.02±14.40 years. Symptom onset was 15 (1-365) days. The most common complaints at initial presentation were hemiparesis or hemiplegia, sensory complaints, and cognitive impairment (aphasia or apraxia). The lesions were most commonly localized in the frontal lobe (42.9 %). Mass effect was 17.1 %, edema 60 %, diffusion restriction 62.1 %, and contrast enhancement 71.9 % (mostly ring-shaped (68.8 %)) on MR images. Acute onset and OCB type-2 positivity were associated with MS diagnosis. On the other hand, CSF protein levels above 45 mg/dL were found to be related to non-MS etiologies. Only the predominance of aphasia or apraxia at onset was a risk factor for early high disability (EDSS>4; 3rd month). Subacute-chronic onset, being older than 40 years, or having brainstem symptoms at onset were independent risk factors for late high disability (2nd year). CONCLUSION: Acute onset or OCB type 2 positivity is a clue for early diagnosis of MS, while elevated CSF protein is a clue for demyelinating diseases other than MS. Presentation with cognitive dysfunction at onset is an independent risk factor for early disability, while age above 40 years, subacute-chronic presentation and brainstem findings at presentation are independent risk factors for late disability.

Identifying the risk factors for intracranial herniation in patients with cerebral venous thrombosis.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is not as well understood as an ischemic stroke of arterial origin. Although the prognosis of CVST is usually good, parenchymal lesions may occur in some patients, and the development of intracranial herniation may result in death. For this reason, recognizing the risk factors for intracranial herniation and accurately determining those patients who should undergo decompressive craniectomy is important. OBJECTIVE: This study aims to determine the risk factors for intracranial herniation in patients with CVST. METHODS: A total of 177 patients diagnosed with CVST between 2015 and 2021 in our tertiary center were retrospectively included in this study. RESULTS: Of the 177 patients, 124 were female and 53 were male with mean ages of 40.65 ± 13.23 and 44.13 ± 17.09, respectively. Among those, 18 patients had developed intracranial herniation. A significant statistical relationship was observed between superior sagittal sinus thrombosis, sinus rectus thrombosis, venous collateral score, nonhemorrhagic venous infarct, presence of malignancy, small juxtacortical hemorrhage, and cortical vein thrombosis. The binary logistic regression analysis results showed that the most significant variables were the venous collateral score of 0, malignancy, and small juxtacortical hemorrhages. CONCLUSION: This study identified small juxtacortical hemorrhages, the presence of malignancy, and a venous collateral score of 0 to be independent risk factors for intracranial herniation in CVST patients. Drawing on these results, we recommend close clinical observation of CVST patients, as they may be candidates for decompressive craniectomy.

ANTECEDENTES: A trombose do seio venoso cerebral (CVST) não é tão bem compreendida como um acidente vascular cerebral isquémico de origem arterial. Embora o prognóstico de CVST seja geralmente bom lesões parenquimatosas podem ocorrer em alguns pacientes e o desenvolvimento de herniação intracraniana pode resultar em morte. Por esse motivo é importante reconhecer os fatores de risco para hérnia intracraniana e determinar com precisão os pacientes que devem ser submetidos à craniectomia descompressiva. OBJETIVO: Este estudo tem como objetivo determinar os fatores de risco para herniação intracraniana em pacientes com CVST. MéTODOS: Um total de 177 pacientes diagnosticados com CVST entre 2015 e 2021 em nosso centro terciário foram retrospectivamente incluídos neste estudo. RESULTADOS: Dos 177 pacientes 124 eram do sexo feminino e 53 do masculino com média de idade de 40 65 ± 13 23 e 44 13 ± 17 09 respectivamente. Destes 18 pacientes desenvolveram hérnia intracraniana. Uma relação estatística significativa foi observada entre trombose do seio sagital superior trombose do seio reto escore de colateral venosa infarto venoso não hemorrágico presença de malignidade pequena hemorragia justacortical e trombose da veia cortical. Os resultados da análise de regressão logística binária mostraram que as variáveis mais significativas foram o escore colateral venoso de 0 malignidade e pequenas hemorragias justacorticais. CONCLUSãO: Este estudo identificou pequenas hemorragias justacorticais a presença de malignidade e um escore colateral venoso de 0 como fatores de risco independentes para herniação intracraniana em pacientes CVST. Com base nesses resultados recomendamos uma observação clínica rigorosa dos pacientes CVST pois eles podem ser candidatos à craniectomia descompressiva.

Determining flow stasis zones in the intracranial aneurysms and the relation between these zones and aneurysms' aspect ratios after flow diversions.

BACKGROUND: Flow diverter stents (FDSs) are widely used to treat aneurysms in the clinic. However, even the same flow diverter (FD) use on different patients' aneurysm sites can cause unexpected hemodynamics at the aneurysm region yielding low success rates for the overall treatment. Therefore, the present study aims to unfold why FDs do not work as they are supposed to for some patients and propose empirical correlation along with a contingency table analysis to estimate the flow stasis zones in the aneurysm sacs. METHODS: The present work numerically evaluated the use of FRED4518 FDS on six patients' intracranial aneurysms based on patient-specific aneurysm geometries. Computational fluid dynamics (CFD) simulation results were further processed to identify the time evolution of weightless blood particles for six patients' aneurysms. RESULTS: Stagnation zone formation, incoming and outgoing blood flow at the aneurysm neck, and statistical analysis of six patients indicated that FRED4518 showed a large flow stasis zone for an aspect ratio larger than 0.75. However, FRED4518, used for aneurysms with an aspect ratio of less than 0.65, caused small stagnant flow zones based on the number of blood particles that stayed in the aneurysm sac. CONCLUSION: A patient-specific empirical equation is derived considering aneurysms' morphological characteristics to determine the amount of stagnated fluid flow zones and magnitude of the mean aneurysm velocity in the aneurysm sac for FRED4518 based on weightless fluid particle results for the first time in the literature. As a result, numerical simulation results and patient data-driven equation can help perceive stagnated fluid zone amount before FRED4518 placement by shedding light on neuro-interventional surgeons and radiologists.

Different Cases, Different Manifestations of Post-COVID-19 Retinal Artery Occlusion: A Case Series.

Coronavirus disease 2019 (COVID-19) is a procoagulant disease that increases the risk of clinically evident thrombotic complications. Herein we present 3 cases with different retinal artery occlusions that emerged soon after the diagnosis of COVID-19. The first patient had central retinal artery occlusion (CRAO) that resulted in visual loss in one eye. The second patient had inflammatory peripheral retinal artery occlusion, vasculitis, and uveitis which did not affect vision. The third patient presented with CRAO following the progression from orbital cellulitis to orbital apex syndrome. Interestingly, CRAO progressed to internal carotid artery occlusion in this case within days and resulted in monocular visual loss. Variations in the underlying pathophysiology and the characteristics of individual immune responses in patients with COVID-19 may be factors that determine differences in clinical manifestations. This article aims to describe different presentations of COVID-19-related retinal artery occlusions and discuss possible pathophysiological aspects.