Contrast Angiography Research Articles

Epidemiology of headache presentations to United States emergency departments from 2016 to 2023

IntroductionHeadaches are a common condition seen in the Emergency Department (ED), with numerous trials focused on improving care for these patients. However, there is limited recent large-scale, robust data available on the incidence, admission rates, evaluation, and treatment in the ED setting. MethodsThis was a cross-sectional study of ED presentations for headache from 1/1/2016 to 12/31/2023 using the Epic Cosmos national database. All ED visits with headache-relevant ICD-10 coding were included. Outcomes included percentage of total ED visits, admission rates, computed tomography (CT) brain imaging, lumbar puncture (LP) performance, and medication administration. Medications were analyzed by class (NSAIDs, acetaminophen, dopamine antagonists, diphenhydramine, opioids, intravenous fluids, caffeine, and magnesium sulfate). Subgroup analyses were performed by specific types of dopamine antagonists. ResultsOf 188,482,644 ED encounters, 6,007,090 (3.2%) were due to headache. Of these, 246,082 (4.1%) were admitted. Nearly half (46.6%) of patients received at least one CT. Rates of CT head without contrast increased from 38.2% to 47.9% over time, while rates of CT angiography rose from 2.8% to 10.2%. 1.4% of all patients received an LP, with rates decreasing from 1.8% to 1.1% over time. The most common medication was NSAIDs (45.3%), followed by dopamine antagonists (44.8%), diphenhydramine (38.1%), acetaminophen (24.8%), opioids (16.3%), magnesium sulfate (0.2%), and caffeine (0.1%). 50.8% of patients received intravenous fluids. Rates of opioids declined over time, while dopamine antagonists, acetaminophen, and intravenous fluid administration increased. ConclusionHeadaches represent a common reason for ED presentation, with approximately 4% of patients being admitted. Imaging is frequently performed, with rises in CT without contrast and CT angiography rates over time, while LP rates have been declining. NSAIDs remain the most common medication given, with opioids declining over time while non-opioid agents such as dopamine antagonists have increased. These findings can help inform health policy initiatives, such as those focused on radiologic imaging and evidence-based medication administration.

Variable-density velocity-selective magnetization preparation for non-contrast-enhanced peripheral MR angiography.

Velocity-selective (VS) magnetization preparation has shown great promise for non-contrast-enhanced (NCE) magnetic resonance angiography (MRA) with the ability to generate positive angiographic contrast directly using a single 3D acquisition. However, existing VS-MRA methods have an issue of aliased saturation around a certain velocity, known as velocity field-of-view (vFOV), which can cause undesired signal loss in arteries. This study aimed to develop a new version of the VS preparation pulse sequence that overcomes the aliased saturation problem in conventional VS preparation. Utilizing the fact that an excitation profile is the Fourier transform of excitation k-space sampling, we sampled the k-space in a non-uniform fashion by scaling gradient pulses accordingly to have aliased excitation diffused over velocity. The variable density sampling function was numerically optimized to maximize the average of the velocity passband signal while minimizing its variance. The optimized variable density VS magnetization was validated through Bloch simulations and applied to peripheral NCE MRA in healthy subjects. The in-vivo experiments showed that the proposed variable density VS-MRA significantly lowered arterial signal loss observed in conventional VS-MRA, as evidenced by a higher arterial signal-to-noise ratio (58.50 ± 14.29 vs. 55.54 ± 12.32; p < 0.05) and improved artery-to-background contrast-to-noise ratio (22.75 ± 7.57 vs. 20.60 ± 6.51; p < 0.05).

Automatic segmentation of intraluminal thrombosis of abdominal aortic aneurysms from CT angiography using a mixed-scale-driven multiview perception network (M2Net) model

Intraluminal thrombosis (ILT) plays a critical role in the progression of abdominal aortic aneurysms (AAA). Understanding the role of ILT can improve the evaluation and management of AAAs. However, compared with highly developed automatic vessel lumen segmentation methods, ILT segmentation is challenging. Angiographic contrast agents can enhance the vessel lumen but cannot improve boundary delineation of the ILT regions; the lack of intrinsic contrast in the ILT structure significantly limits the accurate segmentation of ILT. Additionally, ILT is not evenly distributed within AAAs; its sparsity and scattered distributions in the imaging data pose challenges to the learning process of neural networks. Thus, we propose a multiview fusion approach, allowing us to obtain high-quality ILT delineation from computed tomography angiography (CTA) data. Our multiview fusion network is named Mixed-scale-driven Multiview Perception Network (M2Net), and it consists of two major steps. Following image preprocessing, the 2D mixed-scale ZoomNet segments ILT from each orthogonal view (i.e., Axial, Sagittal, and Coronal views) to enhance the prior information. Then, the proposed context-aware volume integration network (CVIN) effectively fuses the multiview results.Using contrast-enhanced computed tomography angiography (CTA) data from human subjects with AAAs, we evaluated the proposed M2Net. A quantitative analysis shows that the proposed deep-learning M2Net model achieved superior performance (e.g., DICE scores of 0.88 with a sensitivity of 0.92, respectively) compared with other state-of-the-art deep-learning models. In closing, the proposed M2Net model can provide high-quality delineation of ILT in an automated fashion and has the potential to be translated into the clinical workflow.

Alginate-Encapsulated Mesenchymal Stromal Cells Improve Hind Limb Ischemia in a Translational Swine Model.

Cellular therapies have been investigated to improve blood flow and prevent amputation in peripheral artery disease with limited efficacy in clinical trials. Alginate-encapsulated mesenchymal stromal cells (eMSCs) demonstrated improved retention and survival and promoted vascular generation in murine hind limb ischemia through their secretome, but large animal evaluation is necessary for human applicability. We sought to determine the efficacy of eMSCs for peripheral artery disease-induced limb ischemia through assessment in our durable swine hind limb ischemia model. Autologous bone marrow eMSCs or empty alginate capsules were intramuscularly injected 2 weeks post-hind limb ischemia establishment (N=4/group). Improvements were quantified for 4 weeks through walkway gait analysis, contrast angiography, blood pressures, fluorescent microsphere perfusion, and muscle morphology and histology. Capsules remained intact with mesenchymal stromal cells retained for 4 weeks. Adenosine-induced perfusion deficits and muscle atrophy in ischemic limbs were significantly improved by eMSCs versus empty capsules (mean±SD, 1.07±0.19 versus 0.41±0.16, P=0.002 for perfusion ratios and 2.79±0.12 versus 1.90±0.62 g/kg, P=0.029 for ischemic muscle mass). Force- and temporal-associated walkway parameters normalized (ratio, 0.63±0.35 at week 3 versus 1.02±0.19 preligation; P=0.17), and compensatory footfall patterning was diminished in eMSC-administered swine (12.58±8.46% versus 34.85±15.26%; P=0.043). Delivery of eMSCs was associated with trending benefits in collateralization, local neovascularization, and muscle fibrosis. Hypoxia-cultured porcine mesenchymal stromal cells secreted vascular endothelial growth factor and tissue inhibitor of metalloproteinase 2. This study demonstrates the promise of the mesenchymal stromal cell secretome at improving peripheral artery disease outcomes and the potential for this novel swine model to serve as a component of the preclinical pipeline for advanced therapies.

A Novel Evaluation for Vertebral Artery Course Using 3D Magnetic Resonance Imaging with Computed Tomography -like Bone Contrast and Magnetic Resonance Angiography: A Proof of Concept Study

Vertebral artery (VA) injury poses a significant risk in cervical spine surgery, necessitating accurate preoperative assessment. This study aims to introduce and validate a novel approach that combines the Fast field echo that resembles a computed tomography using restricted echo spacing (FRACTURE) sequence with Time of Flight (TOF) Magnetic Resonance Angiography (MRA) for comprehensive evaluation of VA courses in the cervical spine. A total of eight healthy volunteers and two patients participated in this study. The FRACTURE sequence provided high-resolution bone images of the cervical spine, while TOF MRA offered non-invasive vascular imaging. Fusion images were created by merging FRACTURE and MRA modalities to simultaneously visualize cervical spine structures and VA courses. Board-certified orthopedic spine surgeons independently evaluated images to assess the visibility of anatomical characteristics of the VA course by Likert-scale. The FRACTURE-MRA fusion images effectively depicted the extraosseous course of the VA at the craniovertebral junction, the intraosseous course of the VA at the craniovertebral junction, the VA entrance level to the transverse foramen, and the side-to-side asymmetry of bilateral VAs. Additionally, clinical cases demonstrated the utility of the proposed technique in identifying anomalies and guiding surgical interventions. The integration of the FRACTURE sequence and TOF MRA presents a promising methodology for the precise evaluation of VA courses in the cervical spine. This approach improves preoperative planning for cervical spine surgery with detailed anatomy and is a valuable alternative to conventional methods without contrast agents.

Transient cortical blindness after diagnostic cerebral angiography – A single center report

BackgroundTransient cortical blindness (TCB) has been reported as a complication after diagnostic cerebral angiography in 0.3–1% of cases. Our aim was to observe the frequency of TCB after diagnostic cerebral angiography over a period of 11 years using only hypo-osmolar, nonionic contrast agents and following a protocol to reduce both the total volume of injected contrast agent and the number of angiography series obtained. MethodsWe retrospectively included all 2431 patients who received diagnostic cerebral angiographies at our institution. Primary outcome measure was the occurrence of TCB after diagnostic cerebral angiography, hypothesizing that the occurrence of TBC depends on the volume of contrast agent and angiography of the vertebrobasilary arteries. ResultsOver the analyzed time period of 11 years, we did not observe a single case of TCB following diagnostic cerebral angiography. The median contrast volume used was 100 ml (IQR, 100–200), ranging from 15 ml to 500 ml. In our cohort, 61.5% of patients received a selective catheterization of the vertebrobasilary territory. In 99.8% of angiographies iopamidol was used a contrast agent. ConclusionOur results indicate that following to certain aspects of the angiography protocol (using the hypoosmolar, non-ionic contrast agent iopamidol and reducing the number of catheterized vessels and angiography series to a diagnostic minimum) the frequency of transient cortical blindness as a complication of diagnostic cerebral angiography considerably can be very low.

Ultra-Low Contrast Angiography and Zero-Contrast Percutaneous Coronary Intervention in Chronic Kidney Disease Patients Under Intra Vascular Ultrasound Guidance - A Prospective Short-Term Outcome Study

Ultra-Low Contrast Angiography and Zero-Contrast Percutaneous Coronary Intervention in Chronic Kidney Disease Patients Under Intra Vascular Ultrasound Guidance - A Prospective Short-Term Outcome Study

Bilateral Renal Artery Aneurysm: Clinical Case Report

Introduction: Renal artery aneurysms are rare vascular anomalies and even more exceptional is they are located in both renal arteries in this case. The literature reports an approximate occurrence of 0.01 to 0.09 in the general population. Its appearance predominates in the female gender and the most common location is in the right renal artery. The peak age of occurrence is between 40 and 60 years. Its physiopathology is generally caused by inflammatory processes and muscular fibrodysplasias; however, when they are intraparenchymal, they are associated with congenital collagenopathies or polytraumatisms. Clinical case: 74-year-old male patient with a personal history of Parkinson's disease, adrenocortical adenoma and diverticulosis. During the study of his basic pathology, a simple and contrast angiography of the abdomen was performed, after the verification of his renal function, which was within normal ranges (urea 44.4 mg/dl, creatinine 1.04 mg/dl). The presence of images suggestive of aneurysms in the left renal arteries was reported as an incidental finding, therefore he was referred to the Department of Angiology and Vascular Surgery. The clinical case was discussed by the medical staff of the Department of Angiology and Vascular Surgery, concluding that the rare bilateral renal artery aneurysm pathology does not meet criteria for open or endovascular surgery, therefore it is indicated to continue regular monitoring to determine possible growth and intervention in case of risk of rupture. Conclusions: With the development of imaging techniques, the incidental finding of renal artery aneurysm is going to be more and more frequent. The presence of symptoms is also fundamental in making decisions regarding the need for surgery. In asymptomatic patients, non-aggressive treatment is recommended; however, the clinical evaluation of each patient should be individualized.

The effect of Fiber Optic RealShape technology on the reduction of radiation during complex endovascular surgery

ObjectiveDespite the advantages that fenestrated endovascular aortic repair has over open repair, it is accompanied by the consequence of radiation exposure, which can result in long-term complications for both the patient and surgical staff. Fiber Optic RealShape (FORS) technology is a novel advancement that uses emitted light from a fiber optic wire and enables the surgeon to cannulate vessels in real time without live fluoroscopy. This technology has been implemented at select centers to study its effectiveness for cannulation of target vessels and its impact on procedural radiation. MethodsWe collected prospective data on physician-modified endograft (PMEG) cases before and after the introduction of FORS technology. FORS PMEGs were matched with up to three conventional fluoroscopy cases by number of target vessels, inclusion of a bifurcated device below, aneurysm extent, and patient body mass index. The procedural radiation parameters were compared between these cohorts. Within the FORS cohort, we analyzed the rate of successful target vessel cannulation for all cases done with this technology (including cases other than PMEGs), and we compared the radiation between the cannulations using only FORS with those that abandoned FORS for conventional fluoroscopy. ResultsNineteen FORS PMEGs were able to be matched to 45 conventional fluoroscopy cases. Procedures that used FORS technology had significantly reduced total air kerma (527 mGy vs 964 mGy), dose area product (121 Gy∗cm2 vs 186 Gy∗cm2), fluoroscopy dose (72.1 Gy∗cm2 vs 132.5 Gy∗cm2), and fluoroscopy time (45 minutes vs 72 minutes). There was no difference in procedure length, total contrast, or digital subtraction angiography. Within FORS cases, 66% of cannulations were completed using only FORS. Cannulations using only FORS had significant reduction of navigation air kerma (5.0 mGy vs 26.5 mGy), dose area product (1.2 Gy∗cm2 vs 5.1 Gy∗cm2), and fluoroscopy time (0.6 minutes vs 2.3 minutes) compared with cannulations abandoning FORS for conventional fluoroscopy. ConclusionsThis study demonstrates the advantages of FORS for total procedural radiation as well as during individual cannulation tasks. The implementation of FORS for target vessel catheterization has the potential to decrease the total degree of radiation exposure for the patient and surgical staff during complex endovascular aortic surgeries.

Accuracy of the Injection-Based Occlusion Tool Utilizing Saline and Glucose Solution in Cryoballoon Ablation Guided by a Novel Dielectric Imaging System.

Introduction: The aim of this study is to assess the accuracy of the injection-based occlusion (IBO) tool utilizing saline and glucose solution in verifying pulmonary vein (PV) occlusion during cryoballoon ablation guided by a novel dielectric system (KODEX-EPD system). Methods: In this retrospective study, we enrolled 34 consecutive patients with paroxysmal atrial fibrillation (AF) who underwent their initial cryoballoon ablation procedure guided by the KODEX-EPD system. PV occlusion was firstly assessed by the IBO tool utilizing saline or glucose solution and then verified by direct contrast angiography. Patients were divided into two groups according to the fluid used in the IBO tool: the Saline Group and the Glucose Group. Results: The overall procedure time and fluoroscopy time were comparable between the Saline Group and the Glucose Group (113.7 ± 18.3 vs. 108.4 ± 15.9 min; p = 0.375 and 10.1 ± 3.7 vs. 9.3 ± 3.5 min; p = 0.559). The IBO tool was utilized a total of 138 times in the Saline Group and 135 times in the Glucose Group. When assessing PV occlusion, the IBO tool using saline demonstrated a sensitivity of 92.6% and a specificity of 95.2% compared to angiography. Similarly, the IBO tool utilizing glucose solution showed a sensitivity of 93.2% and a specificity of 96.1%. Conclusions: The IBO tool utilizing non-contrast fluid, saline and glucose solution, demonstrates a high level of sensitivity and specificity in accurately predicting PV occlusion during cryoablation procedures. Both the saline and glucose solutions used in the IBO tool show promising results in effectively assessing PV occlusion.

A case report of spontaneous pectoral hematoma in a male with background antiplatelet therapy after severe COVID-19 infection

BackgroundSpontaneous muscle hematoma is a rare complication in hospitalized patients with COVID-19. We present a case of spontaneous pectoral hematoma occurring after COVID-19 infection and anticoagulation therapy.Case presentationA 69-year-old male presented to the hospital with a two-week history of shortness of breath and a one-week history of high fever. Despite testing positive for COVID-19, the patient’s symptoms did not improve with two doses of ritonavir-boosted nirmatrelvir (Paxlovid). A chest CT scan revealed pulmonary infection and SpO2 tested between 80% and 85% at rest in local hospital. The patient transferred to our intensive care unit, then received multiple treatments, including high flow nasal oxygen (HFNO), antibiotics, methylprednisolone, IL-6 receptor antagonist monoclonal antibody (tocilizumab), and an increased D-Dimer level leaded to intermediate dose of anticoagulation therapy. However, on the 10th day of hospitalization, the patient developed a hematoma in the left pectoralis major muscle. This was accompanied by hemorrhagic shock, necessitating the administration of norepinephrine, fluid resuscitation, and a blood transfusion. Arterial embolization was performed to manage the bleeding, resulting in stabilization of the patient’s condition. Following discharge, the patient experienced an uneventful recovery over a period of six months.ConclusionsSevere COVID-19 patients undergoing routine therapeutic anticoagulation may experience fatal bleeding complications. The ideal dosage of anticoagulants for these patients remains uncertain, especially in the patient with a background of anticoagulation or dual antiplatelet therapy. We present a case of spontaneous muscle hematoma accompanied by hemorrhagic shock. The notable reduction in hemoglobin levels indicated significant bleeding, which was confirmed through contrast angiography and cured by arterial embolization. This case underscores the importance of additional research to determine the appropriate utilization of therapeutic anticoagulation in severe COVID-19 patients already undergoing antithrombotic therapy.

Differences in radiopacity among CT contrast agents and concentrations: A quantitative study.

Several studies in the literature have attempted to subjectively assess the degree of visualization of different neurovascular structures using different contrast agents and concentrations. Given the recent contrast shortages, we aim to objectively compare the radiopacity achieved with four angiographic contrast agents used in clinical practice. Isovue 370, Visipaque 320, Omnipaque 300, and Isovue 300 were each drawn up at 25%, 50%, 75%, and 100% concentrations and compared against normal saline and air syringes. CT scans were obtained, and regions of interest were analyzed for radiopacity using Hounsfield unit (HU) measurements. An aneurysm model with different contrast concentrations was also scanned and dimensions compared. Two-tailed t-tests and Cohen's d coefficients were applied to assess for differences in mean HU measurements. Isovue 370 and Isovue 300 had the highest and lowest mean HU, respectively (p<.001). Visipaque 320 at 25% concentration had the lowest mean HU at -.76. Statistically similar agents (p<.05) were Visipaque 320 and Omnipaque 300 at a 100% concentration (p=.30), and Omnipaque 300 and Isovue 300 at a 25% concentration (p=.73). Aneurysm dimensions among Isovue 370, Visipaque 320, and Omnipaque 300 were all similar, whereas with Isovue 300, the dimensions were significantly smaller (p<.05). Isovue 370 provides the highest HU radiopacity and the most accurate aneurysm measurements. Angiographic measurements obtained with Isovue 300 may underestimate the actual aneurysmal dimensions. Visipaque 320 and Omnipaque 300 at 100% concentration have similar mean HUs and are beneficial for patients with chronic kidney or cardiac disease.

Understanding the Brain-based Determination of Death When Organ Recovery Is Performed With DCDD In Situ Normothermic Regional Perfusion.

Understanding the Brain-based Determination of Death When Organ Recovery Is Performed With DCDD In Situ Normothermic Regional Perfusion.

Intravascular Ultrasound Guidance During Peripheral Vascular Interventions: Long-term Clinical Outcomes and Costs From the Japanese Perspective.

The value of intravascular ultrasound (IVUS) guidance during peripheral vascular revascularization procedures is incompletely understood. Moreover, data on long-term clinical outcomes and costs are limited. The objective of this study was to compare outcomes and costs between IVUS and contrast angiography alone in patients undergoing peripheral revascularization procedures in Japan. This retrospective comparative analysis was performed using the Japanese Medical Data Vision insurance claims database. All patients undergoing revascularization for peripheral artery disease (PAD) between April 2009 and July 2019 were included. Patients were followed until July 2020, death, or a subsequent revascularization procedure for PAD. Two patient groups were compared: one undergoing IVUS imaging or the other contrast angiography alone. The primary end point was major adverse cardiac and limb events, including all-cause-mortality, endovascular thrombolysis, subsequent revascularization procedures for PAD, stroke, acute myocardial infarction, and major amputations. Total health care costs were documented over the follow-up and compared between groups, using a bootstrap method. The study included 3956 patients in the IVUS group and 5889 in the angiography alone group. Intravascular ultrasound was significantly associated with reduced risk of a subsequent revascularization procedure (adjusted hazard ratio: 0.25 [0.22-0.28]) and major adverse cardiac and limb events (0.69 [0.65-0.73]). The total costs were significantly lower in the IVUS group, with a mean cost saving over follow-up of $18 173 [$7 695-$28 595] per patient. The use of IVUS during peripheral revascularization provides superior long-term clinical outcomes at lower costs compared with contrast angiography alone, warranting wider adoption and fewer barriers to IVUS reimbursement for patients with PAD undergoing routine revascularization. Intravascular ultrasound (IVUS) guidance during peripheral vascular revascularization has been introduced to improve the precision of the procedure. However, questions over the benefit of IVUS in terms of long-term clinical outcome and over cost have limited its use in everyday clinical practice. This study, performed in a Japanese health insurance claims database, demonstrates that use of IVUS provides a superior clinical outcome over the long term at a lower cost compared to angiography alone. These findings should encourage clinicians to use IVUS in routine peripheral vascular revascularization procedures and encourage providers to reduce barriers to use.

Echocardiogram-Guided Balloon Valvuloplasty of the Aortic Valve in Neonates and Infants Reduces Contrast Exposure with Maintained Efficacy and Less Aortic Regurgitation.

Balloon aortic valvuloplasty (BAV) is performed in children with significant aortic stenosis (AS). Traditionally, contrast angiography measures the annulus and assesses aortic regurgitation (AR) after each dilation. Echocardiographic guidance is hypothesized to reduce contrast and radiation exposure, without compromising efficacy or safety. Patients < 10kg undergoing BAV from 2013 to 2022 were retrospectively investigated. Agreement between echocardiographic and angiographic annulus measurements was assessed. Echocardiogram-guided (eBAV) and traditional angiogram-guided (tBAV) outcomes were compared controlling for weight, critical AS, and other congenital heart disease (CHD). Twelve eBAV and 19 tBAV procedures were performed. The median age was 33days, median weight was 4.3kg, 7 patients (23%) had critical AS, and 9 patients (29%) had other CHD. Annulus measurements by intraprocedural echocardiography and angiography displayed excellent correlation (ICC 0.95, p < 0.001). eBAV patients received less contrast (0.5 vs 3.5ml/kg, p < 0.01). Five recent eBAV procedures were performed contrast free. Radiation exposure was not statistically different between the eBAV and tBAV groups (155 vs 313µGy·M2, p = 0.12). One eBAV patient (8%) and 3tBAV patients (16%, p = 0.62) experienced serious adverse events. Technical success (gradient < 35mmHg and increase in AR by ≤ 1 grade) occurred in 11 eBAV patients (92%) and 16 tBAV patients (84%, p = 0.22). AR increased in 2 eBAV patients (17%) and 8 tBAV patients (44%, p = 0.02). eBAV was associated with similar efficacy and significantly lower contrast exposure and risk of aortic regurgitation. There was strong agreement between aortic valve annulus measurements by intraprocedural echocardiography and angiography, ultimately permitting contrast free BAV.

Consensus on renovascular hypertension: diagnosis and treatment

The clinical significance of renovascular arterial hypertension is determined by it is high prevalence as well as it is negative impact on prognosis. The most common causes of renovascular arterial hypertension are atherosclerotic stenosis of the renal arteries and fibromuscular dysplasia. Renovascular arterial hypertension is characterized by the development of blood pressure resistant to antihypertensive therapy with an unfavorable prognosis of worsening renal function and cardiovascular complications. Currently, the most available screening method in the diagnosis of renovascular arterial hypertension is duplex scanning of the renal arteries. Non-invasive diagnostic methods also include magnetic resonance and multispiral computed tomography with intravenous contrast. Contrast angiography remains “the golden standard” for diagnosing renovascular arterial hypertension and determining the indications for surgical treatment. Together with the use of diagnostic techniques such as measurement of translesion pressure gradient and fractional blood flow reserve, it allows to assess the functional significance of renal artery stenosis. Treatment of renovascular arterial hypertension is a complex process aimed at normalization of blood pressure, improvement of renal function, as well as mortality and cardiovascular risk reduction. To date, the feasibility of endovascular treatment remains an open question. More often the preference is given to conservative treatment. The indications for renal artery revascularization are less obvious, available clinical guidelines and results of large trials are controversial.

Occult contrast retention post-thrombectomy on 24-h follow-up dual-energy CT: Associations and impact on imaging analysis.

Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU). We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema. Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS). Of 125 patients analyzed (median age 71 (IQR = 61-80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75-21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b-3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = -0.035, p = 0.35; MLS rho = 0.035, p = 0.347). Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.

Angiographic Contrast Dye-Induced Blindness and Nonconvulsive Status Epilepticus.

Ognenovski, Mikhail MD; Pirau, Letitia MD; Beimer, Nicholas J. MD; Trobe, Jonathan D. MDEditor(s): Ko, Melissa W. MD; Cestari, Dean M. MD; Quiros, Peter MD; Winges, Kimberly M. MD Author Information

Abstract Number ‐ 120: Using Gadolinium‐based Contrast in Middle Meningeal Artery Embolization: A Case Series

Introduction Nonacute subdural hematoma (SDH) is a common pathology, particularly in the elderly population, affecting 74 persons per 100 000 aged &gt;65 years old. Though surgical evaluation is the current golden standard treatment for symptomatic NASDH, there has been a paradigm shift towards middle meningeal artery embolization (MMAe), which is less invasive and addresses the underlying pathophysiology. MMAe traditionally uses iodine‐based contrast angiography to assess the anatomy and other branches relative to the distribution of the SDH. Due to the abrupt shortage of intravenous iodine‐based contrast secondary to COVID19 pandemic and consequent April 1,2022 lockdown in Shanghai manufacturers (GE Healthcare), we report three successful cases of MMAe utilizing gadolinium‐based contrast angiography. Methods Informed consent that an alternative contrast medium was obtained from the patients. All procedures were done under general anesthesia, see methods below. All patients tolerated the procedures well, without any nausea, urticaria, angioedema, or bronchospasm. On 6–8 weeks outpatient follow‐up and repeat imaging, all patients have near resolution or improvement of SDH size and no lasting post‐procedural complications were reported. Results Case 1: A 50‐year‐old man with history of traumatic SDH (5 months prior) presented with 5 days history of dysarthria and lethargy. Computed tomography head (CTH) revealed non‐acute bilateral subdural hemorrhage with 6 mm left‐to‐right midline shift. Patient then underwent burr hole evacuation of left‐sided subdural hematoma, and subsequently underwent prophylactic left MMAe and upfront right MMAe. With a transradial approach, 41 cc of gadoteridol contrast (ProHANCE) was used for angiography. No significant ophthalmic artery anastomosis was observed. PVA particles measuring 150–250 microns were then injected until there was significant stasis of forward flow and reflux around the catheter tip. Case 2: A 49‐year‐old man with history of traumatic SDH (6 months prior) presented with 1 month history of headaches, word‐difficulty finding and right sided clumsiness. CTH revealed 2.3 cm mixed density left SDH with a 1.6 mm left‐to‐right midline shift. Patient underwent left frontotemporoparietal craniotomy and subdural hematoma evacuation. 3 days later, patient underwent prophylactic left MMAe using a transfemoral approach with 6.1 cc of gadoterate meglumine (Dotarem) contrast for angiography. No definite external‐to‐internal dangerous collateral pathways were noted and no ocular supply was seen. Liquid embolization proceeded utilizing Onyx 34 with penetration into mid‐level meningeal branches. Case 3: A 55‐year‐old woman presented with 2‐week history of headaches and blurry vision. CTH showed a large 2.2 cm left mixed density SDH with 9.6 mm left‐to‐right midline shift. Patient underwent burr hole evacuation of left‐sided subdural hematoma and subsequent left prophylactic MMAe. With a transfemoral approach, 6.7 cc of gadoteridol contrast (ProHANCE) was used for angiography. No obvious external to internal dangerous collateral pathways were noted. The balloon catheter was advanced just proximal to the bifurcation and liquid embolization with Onyx 34 was achieved. The middle meningeal artery demonstrated complete occlusion proximal to the bifurcation. Conclusions This case series suggests that utilizing a gadolinium‐based contrast for angiography to guide MMA embolization is feasible, effective in visualization of dangerous external‐to‐internal anastomoses (including the ophthalmic artery), and safe for patients.

Monitoring mouse brain perfusion with hybrid magnetic resonance optoacoustic tomography.

Progress in brain research critically depends on the development of next-generation multi-modal imaging tools capable of capturing transient functional events and multiplexed contrasts noninvasively and concurrently, thus enabling a holistic view of dynamic events in vivo. Here we report on a hybrid magnetic resonance and optoacoustic tomography (MROT) system for murine brain imaging, which incorporates an MR-compatible spherical matrix array transducer and fiber-based light illumination into a 9.4 T small animal scanner. An optimized radiofrequency coil has further been devised for whole-brain interrogation. System's utility is showcased by acquiring complementary angiographic and soft tissue anatomical contrast along with simultaneous dual-modality visualization of contrast agent dynamics in vivo.