Now showing items 41-60 of 1421

    • Breast Imaging Fellowship Training in the United States: A National Survey of Fellowship Program Directors

      Weinstein, Joshua D; Mehta, Rashmi J; Mehta, Tejas S; Kavandi, Hadiseh; Brook, Alexander; Phillips, Jordana (2023-11-30)
      Objective: To provide an updated characterization of breast imaging fellowship programs in the United States to identify opportunities for improvement and standardization. Methods: An anonymous survey was e-mailed to program directors of breast imaging fellowship programs listed on the Society of Breast Imaging website. The survey was open from April 23, 2021, through May 27, 2021. The survey was deemed exempt by the IRB. Results: Forty-seven of 80 (59%) program directors responded, of which 36/47 (77%) represented programs dedicated 100% to breast imaging, and 11/47 (23%) represented programs dedicated 50%-75% to breast imaging. Common elements to most programs include tumor boards (47/47, 100%), journal clubs (39/47, 83%), case-based teaching sessions (35/47, 74%), didactic lectures (40/47, 85%), and participation in radiology-pathology conferences (29/47, 62%). Mammography Quality and Standards Act audit training (22/47, 47%), mammography quality control training (22/47, 47%), and formal communication training (19/47, 40%) were less common. Most programs provide exposure to wire (42/47, 89%) and wire-free localization procedures (45/47, 96%), but exposure to contrast-enhanced mammography (13/47, 28%) and molecular breast imaging (4/47, 9%) was limited. A small majority of programs (25/47, 53%) do not require weekday call; however, more (31/47, 66%) have weekend call responsibilities. Many programs (29/47, 62%) offer at least 3 weeks of elective time, which may be clinical or nonclinical. Conclusion: Breast imaging fellowship programs vary in curricula, modality exposure, and academic policies. The results of this survey can help guide further efforts to standardize and optimize fellowship training.
    • Migrated coronary stent into the left internal carotid artery: a rescue technique

      Kühn, Anna Luisa; Singh, Jasmeet; Puri, Ajit S (2023-11-08)
      Coronary stent dislodgement and migration is a rare phenomenon that can potentially result in life-threatening complications. We encountered the unusual case of a coronary artery stent that stripped from its delivery balloon and embolised into the left internal carotid artery during percutaneous coronary intervention. Such an event is a stressful experience for the interventional cardiologist but also an uncommonly encountered situation for a neurointerventionalist whose expertise may be sought to help navigate the situation. Planning the interventional approach and taking into consideration the tools available as well as potential complications is crucial to maximise the chances of best possible outcome for the patient. We were able to retrieve the stent safely and successfully, but, at the same time, we were prepared to manage any adverse events in the best way possible.
    • ACR Appropriateness Criteria® Breast Implant Evaluation: 2023 Update

      Chetlen, Alison; Niell, Bethany L; Brown, Ann; Baskies, Arnold M; Battaglia, Tracy; Chen, Andrew; Jochelson, Maxine S; Klein, Katherine A; Malak, Sharp F; Mehta, Tejas S; et al. (2023-11-01)
      This document discusses the appropriate initial imaging in both asymptomatic and symptomatic patients with breast implants. For asymptomatic patients with saline implants, no imaging is recommended. If concern for rupture exists, ultrasound is usually appropriate though saline rupture is often clinically evident. The FDA recently recommended patients have an initial ultrasound or MRI examination 5 to 6 years after initial silicone implant surgery and then every 2 to 3 years thereafter. In a patient with unexplained axillary adenopathy with current or prior silicone breast implants, ultrasound and/or mammography are usually appropriate, depending on age. In a patient with concern for silicone implant rupture, ultrasound or MRI without contrast is usually appropriate. In the setting of a patient with breast implants and possible implant-associated anaplastic large cell lymphoma, ultrasound is usually appropriate as the initial imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.
    • Comparison of Contrast-enhanced Mammography with MRI Utilizing an Enriched Reader Study: A Breast Cancer Study (CONTRRAST Trial).

      Phillips, Jordana; Mehta, Tejas S; Portnow, Leah H; Fishman, Michael D C; Zhang, Zheng; Pisano, Etta D (2023-11-01)
      Background Despite growing interest in using contrast-enhanced mammography (CEM) for breast cancer screening as an alternative to breast MRI, limited literature is available. Purpose To determine whether CEM is noninferior to breast MRI or abbreviated breast MRI (AB MRI) and superior to two-dimensional mammography in an asymptomatic population simulating those who would present for screening and then undergo diagnostic work-up. Materials and Methods This enriched reader study used CEM and MRI data prospectively collected from asymptomatic individuals at a single institution from December 2014 to March 2020. Case sets were obtained at screening, as part of work-up for a screening-detected finding, or before biopsy of a screening-detected abnormality. All images were anonymized and randomized, and all 12 radiologists interpreted them. For CEM interpretation, readers were first shown low-energy images as a surrogate for digital mammography and asked to give a forced Breast Imaging Reporting and Data System score for up to three abnormalities. The highest score was used as the case score. Readers then reviewed the full CEM examination and scored it similarly. After a minimum 1-month washout, the readers similarly interpreted AB MRI and full MRI examinations. Receiver operating characteristic analysis, powered to test CEM noninferiority to full MRI, was performed. Results The study included 132 case sets (14 negative, 74 benign, and 44 malignant; all female participants; mean age, 54 years ± 12 [SD]). The mean areas under the receiver operating characteristic curve (AUCs) for digital mammography, CEM, AB MRI, and full MRI were 0.79, 0.91, 0.89, and 0.91, respectively. CEM was superior to digital mammography (P < .001). No evidence of a difference in AUC was found between CEM and AB MRI and MRI. Conclusion In an asymptomatic study sample, CEM was noninferior to full MRI and AB MRI and was superior to digital mammography. Clinical trial registration no. NCT03482557 and NCT02275871 © RSNA, 2023 Supplemental material is available for this article.
    • Cryo-EM structure of the human cardiac myosin filament

      Dutta, Debabrata; Nguyen, Vu; Campbell, Kenneth S; Padrón, Raúl; Craig, Roger (2023-11-01)
      Pumping of the heart is powered by filaments of the motor protein myosin that pull on actin filaments to generate cardiac contraction. In addition to myosin, the filaments contain cardiac myosin-binding protein C (cMyBP-C), which modulates contractility in response to physiological stimuli, and titin, which functions as a scaffold for filament assembly1. Myosin, cMyBP-C and titin are all subject to mutation, which can lead to heart failure. Despite the central importance of cardiac myosin filaments to life, their molecular structure has remained a mystery for 60 years2. Here we solve the structure of the main (cMyBP-C-containing) region of the human cardiac filament using cryo-electron microscopy. The reconstruction reveals the architecture of titin and cMyBP-C and shows how myosin's motor domains (heads) form three different types of motif (providing functional flexibility), which interact with each other and with titin and cMyBP-C to dictate filament architecture and function. The packing of myosin tails in the filament backbone is also resolved. The structure suggests how cMyBP-C helps to generate the cardiac super-relaxed state3; how titin and cMyBP-C may contribute to length-dependent activation4; and how mutations in myosin and cMyBP-C might disturb interactions, causing disease5,6. The reconstruction resolves past uncertainties and integrates previous data on cardiac muscle structure and function. It provides a new paradigm for interpreting structural, physiological and clinical observations, and for the design of potential therapeutic drugs.
    • First pass effect as an independent predictor of functional outcomes in medium vessel occlusions: An analysis of an international multicenter study

      Radu, Răzvan Alexandru; Costalat, Vincent; Fahed, Robert; Ghozy, Sherief; Siegler, James E; Shaikh, Hamza; Khalife, Jane; Abdalkader, Mohamad; Klein, Piers; Nguyen, Thanh N; et al. (2023-10-27)
      Introduction: First pass effect (FPE), achievement of complete recanalization (mTICI 2c/3) with a single pass, is a significant predictor of favorable outcomes for endovascular treatment (EVT) in large vessel occlusion stroke (LVO). However, data concerning the impact on functional outcomes and predictors of FPE in medium vessel occlusions (MeVO) are scarce. Patients and methods: We conducted an international retrospective study on MeVO cases. Multivariable logistic modeling was used to establish independent predictors of FPE. Clinical and safety outcomes were compared between the two study groups (FPE vs non-FPE) using logistic regression models. Good outcome was defined as modified Rankin Scale 0-2 at 3 months. Results: Eight hundred thirty-six patients with a final mTICI ⩾ 2b were included in this analysis. FPE was observed in 302 patients (36.1%). In multivariable analysis, hypertension (aOR 1.55, 95% CI 1.10-2.20) and lower baseline NIHSS score (aOR 0.95, 95% CI 0.93-0.97) were independently associated with an FPE. Good outcomes were more common in the FPE versus non-FPE group (72.8% vs 52.8%), and FPE was independently associated with favorable outcome (aOR 2.20, 95% CI 1.59-3.05). 90-day mortality and intracranial hemorrhage (ICH) were significantly lower in the FPE group, 0.43 (95% CI, 0.25-0.72) and 0.55 (95% CI, 0.39-0.77), respectively. Conclusion: Over 2/3 of patients with MeVOs and FPE in our cohort had a favorable outcome at 90 days. FPE is independently associated with favorable outcomes, it may reduce the risk of any intracranial hemorrhage, and 3-month mortality.
    • Stent-assisted Woven EndoBridge device for the treatment of intracranial aneurysms: an international multicenter study

      Diestro, Jose Danilo Bengzon; Dibas, Mahmoud; Adeeb, Nimer; Regenhardt, Robert W; Vranic, Justin E; Guenego, Adrien; Lay, Sovann V; Renieri, Leonardo; Balushi, Ali Al; Shotar, Eimad; et al. (2023-10-20)
      Objective: The Woven EndoBridge (WEB) device is an intrasaccular flow disruptor designed for wide-necked bifurcation aneurysms. These aneurysms may require the use of a concomitant stent. The objective of this study was to determine the clinical and radiological outcomes of patients undergoing stent-assisted WEB treatment. In addition, the authors also sought to determine the predictors of a concomitant stent in aneurysms treated with the WEB device. Methods: The data for this study were taken from the WorldWideWEB Consortium, an international multicenter cohort including patients treated with the WEB device. Aneurysms were classified into two groups based on treatment: stent-assisted WEB and WEB device alone. The authors compared clinical and radiological outcomes of both groups. Univariable and multivariable binary logistic regression analyses were performed to determine factors that predispose to stent use. Results: The study included 691 intracranial aneurysms (31 with stents and 660 without stents) treated with the WEB device. The adequate occlusion status did not differ between the two groups at the latest follow-up (83.3% vs 85.6%, p = 0.915). Patients who underwent stenting had more thromboembolic (32.3% vs 6.5%, p < 0.001) and procedural (16.1% vs 3.0%, p < 0.001) complications. Aneurysms treated with a concomitant stent had wider necks, greater heights, and lower dome-to-neck ratios. Increasing neck size was the only significant predictor for stent use. Conclusions: This study demonstrates that there is no difference in the degree of aneurysm occlusion between the two groups; however, complications were more frequent in the stent group. In addition, a wider aneurysm neck predisposes to stent assistance in WEB-treated aneurysms.
    • Leveraging Differences in AI and Human "Vision" to Improve Breast Cancer Detection

      Mehta, Tejas S (2023-10-17)
      Screening mammography is the single most effective test to reduce breast cancer mortality. Despite improvements in mammography technology, including digital breast tomosynthesis, it remains an imperfect test, with one in eight cancers missed at time of interpretation. Supplemental imaging with US, contrast-enhanced MRI, or contrast-enhanced mammography has been recommended in women with higher-than-average risk to improve breast cancer detection. However, challenges arise for women who are not identified as being at higher-than-average risk or who may not have access to these tests. Artificial intelligence (AI) models using deep learning technology have the potential to find cancers not identified by humans, improving the efficacy of screening mammography.
    • Imaging Preferences in Women With a History of Breast Cancer Receiving Contrast-Enhanced Mammography

      Moravia, Lyndia P; Mosaddhegi, Julie; Mehta, Tejas S; Qureshi, Muhammad M; Phillips, Jordana (2023-10-09)
      Objective: There is interest in contrast-enhanced mammography (CEM) to screen breast cancer survivors, yet it is unclear whether they would accept CEM as their annual exam. The purpose of this study was to understand patient preferences to guide CEM implementation for screening. Methods: Consecutive women with breast cancer history who had CEM as their annual mammogram from July 2020 to August 2021 at a single academic institution completed an 18-question survey regarding prior contrast imaging, CEM experience, and comparison to other breast imaging exams. Response proportions were calculated, and chi-square or Fisher's exact test were used to evaluate associations of demographics with responses. Results: A total of 78% (104/133) of women undergoing CEM provided results. Most were satisfied with CEM (99%, 103/104), had nothing to complain about (87%, 90/104), did not find CEM anxiety provoking (69%, 72/104), felt comfortable having contrast for annual imaging (94%, 98/104), were willing to accept the small risk of a contrast reaction if CEM would find their cancer (93%, 97/104), and would like to have CEM for their exam next year (95%, 99/104). Compared with mammography, 23% (24/104) reported CEM was a better experience, and 63% (66/104) reported CEM was about the same. Of those who had prior MRI, the majority reported CEM was better (53%, 29/55) and would prefer CEM if both MRI and CEM had an equal chance of detecting cancer (73%, 41/56). Most preferences did not differ significantly according to demographics. Conclusion: Most women surveyed considered CEM to be satisfactory and preferred compared to other breast screening modalities.
    • First United States multicenter experience with the new-generation FRED X surface-modified flow diversion stent: feasibility, safety, and short-term efficacy

      Abbas, Rawad; Lan, Matthews; Naamani, Kareem El; Atallah, Elias; Salem, Mohamed; Burkhardt, Jan-Karl; Kühn, Anna Luisa; Puri, Ajit; Monteiro, Andre; Levy, Elad I; et al. (2023-10-06)
      Objective: Flow diversion created a paradigm shift in the treatment of intracranial aneurysms. The new flow redirection endoluminal device with X technology (FRED X) is the latest update of the recent Food and Drug Administration-approved FRED. The FRED X is engineered to reduce material thrombogenicity and enhance vessel healing. In this study, the authors aimed to evaluate the feasibility and early safety and efficacy of the new FRED X. Methods: The authors retrospectively collected and analyzed data from patients who had undergone flow diversion with the new FRED X at four tertiary cerebrovascular centers in the United States from February 2022 through July 2022. Results: Forty-four patients with 45 aneurysms treated using 46 devices comprised the overall study cohort and were divided into two groups: 39 patients with unruptured aneurysms and 5 patients with ruptured aneurysms. The mean patient age was 57.7 ± 9.1 years, and most patients were female (84%). Ninety-one percent of the aneurysms were saccular, with the majority (93%) located in the anterior circulation, specifically the posterior communicating (27%) and carotid ophthalmic (27%) territories. The mean maximum aneurysm diameter was 5.6 ± 4.6 mm, and 20% of the lesions had been previously treated. The mean procedure time was 61.6 minutes, with a mean cumulative fluoroscopy time of 24.6 minutes. Additionally, 7% of the lesions received adjunct treatment. Stent placement was successful in 100% of cases, achieving good wall apposition and complete neck coverage. Further, immediate aneurysm contrast stasis > 90% was observed in 61% of cases. Symptomatic postoperative complications occurred in 3 patients in the unruptured cohort and 1 patient in the ruptured cohort. All patients in the study were discharged on dual antiplatelet regimens with a modified Rankin Scale score of 0. At 6 months after treatment, 89% of cases had adequate occlusion, with < 6% of cases having asymptomatic in-stent stenosis. All patients had excellent functional outcomes. Conclusions: FRED X for the treatment of an intracranial aneurysm is technically feasible alone or in conjunction with intrasaccular embolization. In addition, the study results showed very promising early safety and efficacy. Follow-up studies should establish the long-term safety and efficacy profiles of this new stent.
    • Phosphaturic mesenchymal tumor: two cases highlighting differences in clinical and radiologic presentation

      Gu, Joey; Ge, Connie; Joshi, Ganesh; Most, Mathew; Tai, Ryan (2023-10-04)
      Phosphaturic mesenchymal tumors are rare, usually benign neoplasms that occur in the soft tissue or bone and are the cause of nearly all cases of tumor-induced osteomalacia. Tumor-induced osteomalacia due to phosphaturic mesenchymal tumor is a challenging diagnosis to make-patients present with variable clinical and radiologic findings and the culprit neoplasm is often small and can occur anywhere head to toe. We present two cases of phosphaturic mesenchymal tumor in the scapular body and plantar foot. In both cases, the patient endured years of debilitating symptoms before a tissue diagnosis was eventually reached. Descriptions of clinical presentation, laboratory workup, surgical resection, and imaging characteristics, with a focus on CT, MRI, and functional imaging, are provided to assist with the diagnosis and management of this rare entity. A brief review of current literature and discussion of the differential diagnoses of phosphaturic mesenchymal tumor is also provided.
    • Surface modification of neurovascular stents: from bench to patient

      Zoppo, Christopher T; Mocco, J; Manning, Nathan W; Bogdanov, Alexei A. Jr.; Gounis, Matthew J (2023-10-04)
      Flow-diverting stents (FDs) for the treatment of cerebrovascular aneurysms are revolutionary. However, these devices require systemic dual antiplatelet therapy (DAPT) to reduce thromboembolic complications. Given the risk of ischemic complications as well as morbidity and contraindications associated with DAPT, demonstrating safety and efficacy for FDs either without DAPT or reducing the duration of DAPT is a priority. The former may be achieved by surface modifications that decrease device thrombogenicity, and the latter by using coatings that expedite endothelial growth. Biomimetics, commonly achieved by grafting hydrophilic and non-interacting polymers to surfaces, can mask the device surface with nature-derived coatings from circulating factors that normally activate coagulation and inflammation. One strategy is to mimic the surfaces of innocuous circulatory system components. Phosphorylcholine and glycan coatings are naturally inspired and present on the surface of all eukaryotic cell membranes. Another strategy involves linking synthetic biocompatible polymer brushes to the surface of a device that disrupts normal interaction with circulating proteins and cells. Finally, drug immobilization can also impart antithrombotic effects that counteract normal foreign body reactions in the circulatory system without systemic effects. Heparin coatings have been explored since the 1960s and used on a variety of blood contacting surfaces. This concept is now being explored for neurovascular devices. Coatings that improve endothelialization are not as clinically mature as anti-thrombogenic coatings. Coronary stents have used an anti-CD34 antibody coating to capture circulating endothelial progenitor cells on the surface, potentially accelerating endothelial integration. Similarly, coatings with CD31 analogs are being explored for neurovascular implants.
    • Quantitative validation of Monte Carlo SPECT simulation: application to a Mediso AnyScan GATE simulation

      Pells, Sophia; Cullen, David M; Deidda, Daniel; Denis-Bacelar, Ana M; Fenwick, Andrew; Ferreira, Kelley M; Hamilton, David; Heetun, Warda; Julyan, Peter; Needham, George; et al. (2023-09-30)
      Background: Monte Carlo (MC) simulations are used in nuclear medicine imaging as they provide unparalleled insight into processes that are not directly experimentally measurable, such as scatter and attenuation in an acquisition. Whilst MC is often used to provide a 'ground-truth', this is only the case if the simulation is fully validated against experimental data. This work presents a quantitative validation for a MC simulation of a single-photon emission computed tomography (SPECT) system. Methods: An MC simulation model of the Mediso AnyScan SCP SPECT system installed at the UK National Physical Laboratory was developed in the GATE (Geant4 Application for Tomographic Emission) toolkit. Components of the detector head and two collimator configurations were modelled according to technical specifications and physical measurements. Experimental detection efficiency measurements were collected for a range of energies, permitting an energy-dependent intrinsic camera efficiency correction function to be determined and applied to the simulation on an event-by-event basis. Experimental data were collected in a range of geometries with [Formula: see text]Tc for comparison to simulation. The procedure was then repeated with [Formula: see text]Lu to determine how the validation extended to another isotope and set of collimators. Results: The simulation's spatial resolution, sensitivity, energy spectra and the projection images were compared with experimental measurements. The simulation and experimental uncertainties were determined and propagated to all calculations, permitting the quantitative agreement between simulated and experimental SPECT acquisitions to be determined. Statistical agreement was seen in sinograms and projection images of both [Formula: see text]Tc and [Formula: see text]Lu data. Average simulated and experimental sensitivity ratios of ([Formula: see text]) were seen for emission and scatter windows of [Formula: see text]Tc, and ([Formula: see text]) and ([Formula: see text]) for the 113 and 208 keV emissions of [Formula: see text]Lu, respectively. Conclusions: MC simulations will always be an approximation of a physical system and the level of agreement should be assessed. A validation method is presented to quantify the level of agreement between a simulation model and a physical SPECT system.
    • Dissecting aneurysm of the Posterior Cerebral Artery

      Kuhn, Anna Luisa; Puri, Ajit S; Singh, Jasmeet (2023-09-27)
      Posterior circulation aneurysms are more likely to rupture than those in the anterior circulation but also pose more of a challenge for endovascular treatment or neurosurgical clipping. Aneurysms arising from the posterior cerebral artery are rare; dissecting aneurysms are even rarer. Dissecting posterior cerebral artery aneurysms can be spontaneous or post traumatic. Our case depicts a patient with acute subarachnoid hemorrhage due to a ruptured, dissecting posterior cerebral artery aneurysm who underwent successful endovascular treatment by means of flow diversion.
    • Awake intracerebroventricular delivery and safety assessment of oligonucleotides in a large animal model

      Benatti, Hector Ribeiro; Prestigiacomo, Rachel D; Taghian, Toloo; Miller, Rachael; King, Robert; Gounis, Matthew J; Celik, Ugur; Bertrand, Stephanie; Tuominen, Susan; Bierfeldt, Lindsey; et al. (2023-09-26)
      Oligonucleotide therapeutics offer great promise in the treatment of previously untreatable neurodegenerative disorders; however, there are some challenges to overcome in pre-clinical studies. (1) They carry a well-established dose-related acute neurotoxicity at the time of administration. (2) Repeated administration into the cerebrospinal fluid may be required for long-term therapeutic effect. Modifying oligonucleotide formulation has been postulated to prevent acute toxicity, but a sensitive and quantitative way to track seizure activity in pre-clinical studies is lacking. The use of intracerebroventricular (i.c.v.) catheters offers a solution for repeated dosing; however, fixation techniques in large animal models are not standardized and are not reliable. Here we describe a novel surgical technique in a sheep model for i.c.v. delivery of neurotherapeutics based on the fixation of the i.c.v. catheter with a 3D-printed anchorage system composed of plastic and ceramic parts, compatible with magnetic resonance imaging, computed tomography, and electroencephalography (EEG). Our technique allowed tracking electrical brain activity in awake animals via EEG and video recording during and for the 24-h period after administration of a novel oligonucleotide in sheep. Its anchoring efficiency was demonstrated for at least 2 months and will be tested for up to a year in ongoing studies.
    • Transvenous Embolization of Dural Arteriovenous Fistulas Through the Galenic (Deep Venous) System: Multicenter Case Series and Meta-Analysis

      Srinivasan, Visish M; Karahalios, Katherine; Colasurdo, Marco; Rhodenheiser, Emmajane; Scherschinski, Lea; Lazaro, Tyler T; Cortez, Gustavo; Gross, Bradley A; Kuhn, Anna Luisa; Puri, Ajit S; et al. (2023-09-25)
      Background and objectives: Arteriovenous fistulas involving the deep venous system have often been treated with microsurgery or transarterial embolization. Increasing familiarity with transvenous navigation and improved endovascular access systems may facilitate transvenous embolization (TVE) for these rare and challenging lesions. Methods: We performed a retrospective study of neurointerventional databases of 6 high-volume centers. We identified all cases of arteriovenous fistulas with deep transvenous embolizations for arteriovenous fistula. Details regarding demographics, fistula characteristics, treatment considerations, clinical outcomes, and fistula occlusion were obtained and analyzed. The meta-analysis used the same inclusion criteria. Results: Seventeen cases of TVE were identified. The most common reasons for TVE included prior treatment failure with microsurgery (n = 2) or transarterial embolization (n = 3) or inaccessible arterial pedicles (n = 4). For patients with full clinical outcome data (n = 14), 2 patients had worsened modified Rankin Scale, 8 patients had no change, and 4 were improved at a median clinical follow-up of 3.5 months. Angiographic obliteration was achieved in 15/17 cases (88.2%). In 1 case, catheterization around a sharp turn in the basal vein of Rosenthal could not be performed. In another case, despite successful TVE, there was residual lesion which was treated 1 year later by microsurgical clipping and excision. Conclusion: Transvenous approaches for embolization of deep arteriovenous fistulas have become possible with modern endovascular catheter systems and liquid embolics. These lesions can be treated safely and effectively through endovascular approaches, which may spare patients the traversal of deep structures needed for microsurgical approaches to these regions. The outcomes of TVE are comparable with published outcomes of microsurgical interruption.
    • Partial skeletal muscle-specific Drp1 knockout enhances insulin sensitivity in diet-induced obese mice, but not in lean mice

      Kugler, Benjamin A; Lourie, Jared; Berger, Nicolas; Lin, Nana; Nguyen, Paul; DosSantos, Edzana; Ali, Abir; Sesay, Amira; Rosen, H Grace; Kalemba, Baby; et al. (2023-09-09)
      Objective: Dynamin-related protein 1 (Drp1) is the key regulator of mitochondrial fission. We and others have reported a strong correlation between enhanced Drp1 activity and impaired skeletal muscle insulin sensitivity. This study aimed to determine whether Drp1 directly regulates skeletal muscle insulin sensitivity and whole-body glucose homeostasis. Methods: We employed tamoxifen-inducible skeletal muscle-specific heterozygous Drp1 knockout mice (mDrp1+/-). Male mDrp1+/- and wildtype (WT) mice were fed with either a high-fat diet (HFD) or low-fat diet (LFD) for four weeks, followed by tamoxifen injections for five consecutive days, and remained on their respective diet for another four weeks. In addition, we used primary human skeletal muscle cells (HSkMC) from lean, insulin-sensitive, and severely obese, insulin-resistant humans and transfected the cells with either a Drp1 shRNA (shDrp1) or scramble shRNA construct. Skeletal muscle and whole-body insulin sensitivity, skeletal muscle insulin signaling, mitochondrial network morphology, respiration, and H2O2 production were measured. Results: Partial deletion of the Drp1 gene in skeletal muscle led to improved whole-body glucose tolerance and insulin sensitivity (P < 0.05) in diet-induced obese, insulin-resistant mice but not in lean mice. Analyses of mitochondrial structure and function revealed that the partial deletion of the Drp1 gene restored mitochondrial dynamics, improved mitochondrial morphology, and reduced mitochondrial Complex I- and II-derived H2O2 (P < 0.05) under the condition of diet-induced obesity. In addition, partial deletion of Drp1 in skeletal muscle resulted in elevated circulating FGF21 (P < 0.05) and in a trend towards increase of FGF21 expression in skeletal muscle tissue (P = 0.095). In primary myotubes derived from severely obese, insulin-resistant humans, ShRNA-induced-knockdown of Drp1 resulted in enhanced insulin signaling, insulin-stimulated glucose uptake and reduced cellular reactive oxygen species (ROS) content compared to the shScramble-treated myotubes from the same donors (P < 0.05). Conclusion: These data demonstrate that partial loss of skeletal muscle-specific Drp1 expression is sufficient to improve whole-body glucose homeostasis and insulin sensitivity under obese, insulin-resistant conditions, which may be, at least in part, due to reduced mitochondrial H2O2 production. In addition, our findings revealed divergent effects of Drp1 on whole-body metabolism under lean healthy or obese insulin-resistant conditions in mice.
    • Impact of e-ASPECTS software on the performance of physicians compared to a consensus ground truth: a multi-reader, multi-case study

      Kobeissi, Hassan; Kallmes, David F; Benson, John; Nagelschneider, Alex; Madhavan, Ajay; Messina, Steven A; Schwartz, Kara; Campeau, Norbert; Carr, Carrie M; Nasr, Deena M; et al. (2023-09-07)
      Background: The Alberta Stroke Program Early CT Score (ASPECTS) is used to quantify the extent of injury to the brain following acute ischemic stroke (AIS) and to inform treatment decisions. The e-ASPECTS software uses artificial intelligence methods to automatically process non-contrast CT (NCCT) brain scans from patients with AIS affecting the middle cerebral artery (MCA) territory and generate an ASPECTS. This study aimed to evaluate the impact of e-ASPECTS (Brainomix, Oxford, UK) on the performance of US physicians compared to a consensus ground truth. Methods: The study used a multi-reader, multi-case design. A total of 10 US board-certified physicians (neurologists and neuroradiologists) scored 54 NCCT brain scans of patients with AIS affecting the MCA territory. Each reader scored each scan on two occasions: once with and once without reference to the e-ASPECTS software, in random order. Agreement with a reference standard (expert consensus read with reference to follow-up imaging) was evaluated with and without software support. Results: A comparison of the area under the curve (AUC) for each reader showed a significant improvement from 0.81 to 0.83 (p = 0.028) with the support of the e-ASPECTS tool. The agreement of reader ASPECTS scoring with the reference standard was improved with e-ASPECTS compared to unassisted reading of scans: Cohen's kappa improved from 0.60 to 0.65, and the case-based weighted Kappa improved from 0.70 to 0.81. Conclusion: Decision support with the e-ASPECTS software significantly improves the accuracy of ASPECTS scoring, even by expert US neurologists and neuroradiologists.
    • Vascular leiomyoma of the thigh: Classic presentation of a rare tumor with imaging and pathology correlation

      Kulkarni, Ashwini; Tai, Ryan; Bledsoe, Jacob; Joshi, Ganesh (2023-09-06)
      We report a case of a vascular leiomyoma arising from the superficial femoral artery presenting as a non-painful thigh mass in a 55-year-old woman. Leiomyomas typically arise from the uterus and gastrointestinal tract, and rarely arise from vessels. We present this case to emphasize that although extremity leiomyomas are rare, they should be considered if there is a soft tissue mass abutting a vessel. Radiologists should be familiar with the imaging features associated with vascular leiomyomas.
    • Molecular Magnetic Resonance Imaging of Aneurysmal Inflammation Using a Redox Active Iron Complex

      King, Robert M; Gounis, Matthew J; Schmidt, Eric J; Leporati, Anita; Gale, Eric M; Bogdanov, Alexei A. Jr. (2023-09-01)
      Objectives: Inflammation plays a key role in driving brain aneurysmal instability and rupture, but clinical tools to noninvasively differentiate between inflamed and stable aneurysms are lacking. We hypothesize that imaging oxidative changes in the aneurysmal microenvironment driven by myeloid inflammatory cells may represent a noninvasive biomarker to evaluate rupture risk. In this study, we performed initial evaluation of the oxidatively activated probe Fe-PyC3A as a tool for magnetic resonance imaging (MRI) of inflammation in a rabbit model of saccular aneurysm. Materials and methods: The difference in longitudinal relaxivity ( r1 ) in reduced and oxidized states of Fe-PyC3A was measured in water and blood plasma phantoms at 3 T. A rabbit saccular aneurysm model was created by endovascular intervention/elastinolysis with subsequent decellularization in situ. Rabbits were imaged at 4 weeks (n = 4) or 12 weeks (n = 4) after aneurysmal induction, when luminal levels of inflammation reflected by the presence of myeloperoxidase positive cells are relatively high and low, respectively, using a 3 T clinical scanner. Both groups were imaged dynamically using a 2-dimensional T1-weighted fast field echo pulse MRI sequence before and up to 4 minutes postinjection of Fe-PyC3A. Dynamic imaging was then repeated after an injection of gadobutrol (0.1 mmol/kg) as negative control probe. Rabbits from the 12-week aneurysm group were also imaged before and 20 minutes and 3 hours after injection of Fe-PyC3A using an axial respiratory gated turbo-spin echo (TSE) pulse sequence with motion-sensitized driven equilibrium (MSDE) preparation. The MSDE/TSE imaging was repeated before, immediately after dynamic acquisition (20 minutes postinjection), and 3 hours after injection of gadobutrol. Aneurysmal enhancement ratios (ERs) were calculated by dividing the postinjection aneurysm versus skeletal muscle contrast ratio by the preinjection contrast ratio. After imaging, the aneurysms were excised and inflammatory infiltrate was characterized by fluorometric detection of myeloperoxidase activity and calprotectin immunostaining, respectively. Results: In vitro relaxometry showed that oxidation of Fe-PyC3A by hydrogen peroxide resulted in a 15-fold increase of r1 at 3 T. Relaxometry in the presence of blood plasma showed no more than a 10% increase of r1 , indicating the absence of strong interaction of Fe-PyC3A with plasma proteins. Dynamic imaging with Fe-PyC3A generated little signal enhancement within the blood pool or adjacent muscle but did generate a transient increase in aneurysmal ER that was significantly greater 4 weeks versus 12 weeks after aneurysm induction (1.6 ± 0.30 vs 1.2 ± 0.03, P < 0.05). Dynamic imaging with gadobutrol generated strong aneurysmal enhancement, but also strong enhancement of the blood and muscle resulting in smaller relative ER change. In the 12-week group of rabbits, MSDE/TSE imaging showed that ER values measured immediately after dynamic MRI (20 minutes postinjection) were significantly higher ( P < 0.05) in the case of Fe-PyC3A (1.25 ± 0.06) than for gadobutrol injection (1.03 ± 0.03). Immunohistochemical corroboration using anticalprotectin antibody showed that leukocyte infiltration into the vessel walls and luminal thrombi was significantly higher in the 4-week group versus 12-week aneurysms (123 ± 37 vs 18 ± 7 cells/mm 2 , P < 0.05). Conclusions: Magnetic resonance imaging using Fe-PyC3A injection in dynamic or delayed acquisition modes was shown to generate a higher magnetic resonance signal enhancement in aneurysms that exhibit higher degree of inflammation. The results of our pilot experiments support further evaluation of MRI using Fe-PyC3A as a noninvasive marker of aneurysmal inflammation.