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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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DOE OSTI2016

Beyond minimal lepton-flavored Dark Matter

In this paper ,we consider a class of flavored dark matter (DM) theories where dark matter interacts with the Standard Model lepton fields at the renormalizable level. We allow for a general coupling matrix between the dark matter and leptons whose structure is beyond the one permitted by the minimal flavor violation (MFV) assumption. It is assumed that this is the only new source of flavor violation in addition to the Standard Model (SM) Yukawa interactions. The setup can be described by augmenting the SM flavor symmetry by an additional SU(3) χ , under which the dark matter χ transforms. This framework is especially phenomenologically rich, due to possible novel flavor-changing interactions which are not present within the more restrictive MFV framework. As a representative case study of this setting, which we call “beyond MFV” (BMFV), we consider Dirac fermion dark matter which transforms as a singlet under the SM gauge group and a triplet under SU(3) χ . The DM fermion couples to the SM lepton sector through a scalar mediator Φ. Unlike the case of quark-flavored DM, we show that there is no Z 3 symmetry within either the MFV or BMFV settings which automatically stabilizes the lepton-flavored DM. We discuss constraints on this setup from flavor-changing processes, DM relic abundance as well as direct and indirect detections. We find that relatively large flavor-changing couplings are possible, while the dark matter mass is still within the phenomenologically interesting region below the TeV scale. Collider signatures which can be potentially searched for at the lepton and hadron colliders are discussed. Finally, we discuss the implications for decaying dark matter, which can appear if an additional stabilizing symmetry is not imposed.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

SU(5) unification with TeV-scale leptoquarks

It has previously been noted that SU(5) unification can be achieved via the simple addition of light scalar leptoquarks from two split 10 multiplets. We explore the parameter space of this model in detail and find that unification requires at least one leptoquark to have mass below ≈ 16 TeV. We point out that introducing splitting of the 24 allows the unification scale to be raised beyond 10 16 GeV, while a U(1) PQ symmetry can be imposed to forbid dangerous proton decay mediated by the light leptoquarks. The latest bounds from LHC searches are combined and we find that a leptoquark as light as 400 GeV is still permitted. Finally, we discuss the interesting possibility that the leptoquarks required for unification could also be responsible for the 2.6σ deviation observed in the ratio R K at LHCb.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

LHC signals from cascade decays of warped vector resonances

Recently (arXiv:1608.00526), a new framework for warped higher-dimensional compactifications with “bulk” standard model (SM) was proposed: in addition to the UV (Planck scale) and IR (a couple of TeV) branes, there is an intermediate brane, taken to be around 10TeV. The SM matter and Higgs fields propagate from the UV brane down to this intermediate brane only, while gauge and gravity fields propagate in the entire bulk. Such a configuration renders the lightest gauge Kaluza-Klein (KK) states within LHC reach, simultaneously satisfying flavor and CP constraints. In addition, the usual leading decay modes of the lightest KK gauge bosons into top and Higgs bosons are suppressed. This effect permits erstwhile subdominant channels to become significant. These include flavor-universal decays to SM fermions and Higgs bosons, and a novel channel — decay to a radion and a SM gauge boson, followed by radion decay to a pair of SM gauge bosons. In this work, we first delineate the parameter space where the above mentioned cascade decay of gauge KK particles dominates, and thereby can be the discovery mode at the LHC. We then perform a detailed analysis of the LHC signals from this model, finding that 300/fb suffices for evidence of KK-gluon in tri-jet, jet + di-photon and jet + di-boson channels. However, KK photon in photon + di-jet, and KK-W in leptonic W + di-jet require 3000/fb. The crucial feature of this decay chain is a “double” resonance, i.e. 3-particle and 2-particle invariant mass peaks, corresponding to the KK gauge boson and the radion respectively.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Search for new phenomena in final states with b-jets and missing transverse momentum in $ \sqrt{\mathrm{s}} $ = 13 TeV pp collisions with the ATLAS detector

The results of a search for new phenomena in final states with b -jets and missing transverse momentum using 139 fb - 1 of proton-proton data collected at a centre-of-mass energy s = 13 TeV by the ATLAS detector at the LHC are reported. The analysis targets final states produced by the decay of a pair-produced supersymmetric bottom squark into a bottom quark and a stable neutralino. The analysis also seeks evidence for models of pair production of dark matter particles produced through the decay of a generic scalar or pseudoscalar mediator state in association with a pair of bottom quarks, and models of pair production of scalar third-generation down-type leptoquarks. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered by the analysis. Bottom squark masses below 1270 GeV are excluded at 95% confidence level if the neutralino is massless. In the case of nearly mass-degenerate bottom squarks and neutralinos, the use of dedicated secondary-vertex identification techniques permits the exclusion of bottom squarks with masses up to 660 GeV for mass splittings between the squark and the neutralino of 10 GeV. These limits extend substantially beyond the regions of parameter space excluded by similar ATLAS searches performed previously.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Search for high-mass resonances in dilepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV

A search is presented for new high-mass resonances decaying into electron or muon pairs. The search uses proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 36 fb$^{−1}$. Observations are in agreement with standard model expectations. Upper limits on the product of a new resonance production cross section and branching fraction to dileptons are calculated in a model-independent manner. This permits the interpretation of the limits in models predicting a narrow dielectron or dimuon resonance. A scan of different intrinsic width hypotheses is performed. Limits are set on the masses of various hypothetical particles. For the $ {Z}_{\mathrm{SSM}}^{\prime}\left({Z}_{{}^{\psi}}^{\prime}\right) $ particle, which arises in the sequential standard model (superstring-inspired model), a lower mass limit of 4.50 (3.90) TeV is set at 95% confidence level. The lightest Kaluza-Klein graviton arising in the Randall-Sundrum model of extra dimensions, with coupling parameters k/M$_{Pl}$ of 0.01, 0.05, and 0.10, is excluded at 95% confidence level below 2.10, 3.65, and 4.25 TeV, respectively. In a simplified model of dark matter production via a vector or axial vector mediator, limits at 95% confidence level are obtained on the masses of the dark matter particle and its mediator.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Composing effective prediction at five points

Color-kinematics duality in the adjoint has proven key to the relationship between gauge and gravity theory scattering amplitude predictions. In recent work, we demonstrated that at four-point tree-level, a small number of color-dual EFT building blocks could encode all higher-derivative single-trace massless corrections to gauge and gravity theories compatible with adjoint double-copy. One critical aspect was the trivialization of building higher-derivative color-weights — indeed, it is the mixing of kinematics with non-adjoint-type color-weights (like the permutation-invariant d 4 ) which permits description via adjoint double-copy. Here we find that such ideas clarify the predictions of local five-point higher-dimensional operators as well. We demonstrate how a single scalar building block can be combined with color structures to build higher-derivative color factors that generate, through double copy, the amplitudes associated with higher-derivative gauge-theory operators. These may then be suitably mapped, through another double-copy, to higher-derivative corrections in gravity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Probing the photon polarization in B → K*γ with conversion

We re-examine the possibility to measure the photon polarization in B → K*γ decays, via decays in which the photon subsequently undergoes nuclear conversion to a lepton pair. We obtain compact expressions for the full decay-plus-conversion amplitude. With these results we show that interference between the B → (K* → Kπ)γ decay and the γN → ℓ + ℓ – N conversion permits both the ratio and relative weak phase between the left- and right-handed photon amplitudes to be probed by an angular observable, constructed from the final state dilepton, kaon and pion kinematic configuration. Exploiting this technique will be experimentally challenging. However, we present special kinematic cuts that enhance the statistical power of this technique by an O(1) factor. Furthermore, we verify this effect and extract pertinent angular kinematic distributions with dedicated numerical simulations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Exploring nonlocal observables in shock wave collisions

In this paper, we study the time evolution of 2-point functions and entanglement entropy in strongly anisotropic, inhomogeneous and time-dependent N = 4 super Yang-Mills theory in the large N and large ’t Hooft coupling limit using AdS/CFT. On the gravity side this amounts to calculating the length of geodesics and area of extremal surfaces in the dynamical background of two colliding gravitational shockwaves, which we do numerically. We discriminate between three classes of initial conditions corresponding to wide, intermediate and narrow shocks, and show that they exhibit different phenomenology with respect to the nonlocal observables that we determine. Our results permit to use (holographic) entanglement entropy as an order parameter to distinguish between the two phases of the cross-over from the transparency to the full-stopping scenario in dynamical Yang-Mills plasma formation, which is frequently used as a toy model for heavy ion collisions. The time evolution of entanglement entropy allows to discern four regimes: highly efficient initial growth of entanglement, linear growth, (post) collisional drama and late time (polynomial) fall off. Surprisingly, we found that 2-point functions can be sensitive to the geometry inside the black hole apparent horizon, while we did not find such cases for the entanglement entropy.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Improved high-throughput screening technique to rapidly isolate Chlamydomonas transformants expressing recombinant proteins

Abstract The single-celled eukaryotic green alga Chlamydomonas reinhardtii has long been a model system for developing genetic tools for algae, and is also considered a potential platform for the production of high-value recombinant proteins. Identifying transformants with high levels of recombinant protein expression has been a challenge in this organism, as random integration of transgenes into the nuclear genome leads to low frequency of cell lines with high gene expression. Here, we describe the design of an optimized vector for the expression of recombinant proteins in Chlamydomonas , that when transformed and screened using a dual antibiotic selection, followed by screening using fluorescence activated cell sorting (FACS), permits rapid identification and isolation of microalgal transformants with high expression of a recombinant protein. This process greatly reduces the time required for the screening process, and can produce large populations of recombinant algae transformants with between 60 and 100% of cells producing the recombinant protein of interest, in as little as 3 weeks, that can then be used for whole population sequencing or individual clone analysis. Utilizing this new vector and high-throughput screening (HTS) process resulted in an order of magnitude improvement over existing methods, which normally produced under 1% of algae transformants expressing the protein of interest. This process can be applied to other algal strains and recombinant proteins to enhance screening efficiency, thereby speeding up the discovery and development of algal-derived recombinant protein products. Key points • A protein expression vector using double-antibiotic resistance genes was designed • Double antibiotic selection causes fewer colonies with more positive for phenotype • Coupling the new vector with FACS improves microalgal screening efficiency > 60%

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Standardized report template for indeterminate renal masses at CT and MRI: a collaborative product of the SAR Disease-Focused Panel on Renal Cell Carcinoma

Purpose: To create a succinct yet comprehensive evidence-based structured report template for indeterminate renal masses characterized at CT and MRI. Methods: This IRB-exempt, iterative, multi-institutional quality improvement project was informed by published data derived from a multi-institutional survey and a multi-institutional review of CT and MRI radiology reports. A two-stage blinded Delphi process by the 16-member 12-institution Society of Abdominal Radiology Disease-Focused Panel on Renal Cell Carcinoma was conducted to create a structured report template for indeterminate renal masses evaluated at CT and MRI. Individual reporting characteristics were scored by members as ‘core,’ ‘optional,’ or ‘exclude.’ Threshold for inclusion was ≥ 80% support. If < 80% members considered a characteristic a ‘core’ feature, but ≥ 80% considered it either ‘core’ or ‘optional,’ it was considered an ‘optional’ feature. If neither was the case, the characteristic was excluded. Free-text comments were permitted. Characteristics considered ‘core’ by 50–99% of respondents in Round 1 (i.e., nonunanimous support) and uninvestigated free-text comments were assessed in Round 2. Core and optional structured reporting templates were derived. Results: The response rate was 100% in Round 1 (16/16) and Round 2 (16/16). In Round 1, 5 characteristics had unanimous support as ‘core’ features. Following Round 2, 13 characteristics had ≥ 80% support as ‘core’ features, and 10 characteristics had ≥ 80% support as ‘optional’ features. Structured report templates were derived. Discussion: Structured ‘core’ and ‘optional’ templates for indeterminate renal masses at CT and MRI were derived, which may improve compliance with reporting preferred and essential imaging characteristics.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Postpartum Hemorrhage Treated with Gelfoam Slurry Embolization Using the Superselective Technique: Immediate Results and 1-Month MRI Follow-up

To evaluate the efficacy and safety of superselective embolization of the uterine arteries in a postpartum hemorrhage. Between November 2004 and January 2011, a total of 44 consecutive women (median {+-} standard deviation age 34 {+-} 3 years, range 23-41 years) were referred to our institution for postpartum intractable hemorrhage management. All patients were embolized with a microcatheter that was placed deep into the uterine arteries upstream of the cervical arteries. The embolic agent was a mixture of contrast medium and 5 Multiplication-Sign 5 Multiplication-Sign 5 cm pieces of gelfoam (Gelita-Spon) modified into a gelatin emulsion as follows: rapid mixing through a three-way stopcock with two 2.5-ml syringes. A 1-ml syringe was used for injection. One month after embolization, all patients underwent magnetic resonance imaging and clinical examination. Technical and clinical success was obtained in all cases. Thirty-five patients experienced bleeding related to poor retraction of the uterus, 7 patients because of a tear of the cervix and 2 because of a vaginal hematoma. Pre- and postembolization red blood cell transfusions were (mean {+-} standard deviation [SD]) 6 {+-} 1.2 (range 3-8) U and 2 {+-} 0.7 (range 2-4) U, respectively. One-month magnetic resonance imaging follow-up revealed no sign of ischemic myometrium or necrosis, and no instances of uterine rupture and no pelvic vein thrombosis. Incidental findings included two small intramyometrial hematic collections. All uterine arteries were patent via magnetic resonance angiography. Seventeen patients had concomitant fibroids, all of which appeared hypovascular. This technique permits good, safe clinical results with no marked damage to the uterine arteries or the uterus itself.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Unexpected Complication with the New C3 Excluder: Cause and Treatment

The new C3 Gore Excluder delivery system enables both up/downward and rotational repositioning of the device before complete deployment. This contributes to more precise proximal landing and permits facilitation of the contralateral gate cannulation. During separate deployment, the position of the ipsilateral limb can also be readjusted. We have used the modified C3 delivery system in more than 50 patients, and in most cases, we were able to utilize the repositioning options of the device to achieve optimal fixation and sealing. However, we present a case where our attempt to readjust the position of the ipsilateral limb led to upward migration of the main body with coverage of the left renal artery origin. The latter was secured with a bare stent implantation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Randomized Trial of the SMART Stent versus Balloon Angioplasty in Long Superficial Femoral Artery Lesions: The SUPER Study

To determine whether primary stenting reduces the rate of restenosis compared with balloon angioplasty alone in the endovascular treatment of long superficial femoral artery lesions; and to assess the effect of treatment on quality of life. A total of 150 patients with superior femoral artery occlusion or severe stenosis of 5-22 cm length from 17 UK centers were randomized to either primary stenting with the SMART stent or balloon angioplasty (i.e., percutaneous transluminal angioplasty, PTA). Bailout stent placement was permitted in case of inadequate result from PTA. The primary end point was restenosis measured by duplex ultrasound at 1 year. Quality-of-life assessments were performed by the EuroQol (EQ)-5D questionnaire. Mean lesion length was 123.0 mm in the stent group and 116.8 mm in the PTA group. A total of 140 (93.3 %) of 150 had total occlusions. At 12 months' follow-up, restenosis measured by Duplex ultrasound was not significantly different between the stent and PTA groups by intention-to-treat or as-treated analyses: 47.2 versus 43.5 % (p = 0.84) and 40.8 versus 46.7 % (p = 0.68), respectively. There were fewer target lesion revascularizations in patients randomized to stenting, but this did not reach statistical significance (12.5 vs. 20.8 %, p = 0.26). There was no difference in the rate of amputation. Patients in both groups reported improved quality of life. Primary stenting of long lesions in predominantly occluded superficial femoral arteries does not reduce the rate of binary restenosis compared with balloon angioplasty and bailout stenting. Both treatment strategies conferred a meaningful and sustained improvement to the quality of life of patients with severe superficial femoral artery disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Radiologic Percutaneous Gastrostomy in Nondistended Stomach: A Modified Approach

IntroductionGastrostomy tube placement for patients requiring long-term nutritional support may be performed using different techniques including endoscopic, surgical, and percutaneous radiologically guided methods. Radiologically inserted gastrostomy (RIG), typically performed when percutaneous endoscopic gastrostomy is not possible, requires proper gastric distension that is achieved by insufflating air through a nasogastric tube. We describe a simple technique to prevent air escape from the stomach during gastrostomy tube placement. To the best of our knowledge, this technique has not yet been described in the literature.Materials and MethodsFour patients with unsuccessful percutaneous endoscopic gastrostomy were referred for fluoroscopic-guided gastrostomy. One patient had a pyriform sinus tumor and three had an ischemic stroke causing dysphagia. Gastric distention was not achieved in the patients due to air escaping into the bowel during the standard RIG procedure. A modified approach using a balloon catheter inflated in the pylorus to avoid air passing into the duodenum permitted successful RIG.ResultsThe modified RIG procedure was successfully carried out in all cases without complications.DiscussionInadequate air distension of the stomach is an unusual event that causes a failure of gastrostomy tube placement and an increased risk of both major and minor complications. The use of a balloon catheter inflated in the first part of the duodenum prevents the air passage into the bowel allowing the correct positioning of the gastrostomy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Transcatheter Arterial Embolization with a Mixture of Absolute Ethanol and Iodized Oil for Poorly Visualized Endophytic Renal Masses Prior to CT-Guided Percutaneous Cryoablation

PurposeTo retrospectively evaluate the feasibility of transcatheter arterial embolization (TAE) using a mixture of absolute ethanol and iodized oil to improve localization of endophytic renal masses on unenhanced computed tomography (CT) prior to CT-guided percutaneous cryoablation (PCA).Materials and MethodsOur institutional review board approved this retrospective study. From September 2011 to June 2015, 17 patients (mean age, 66.8 years) with stage T1a endophytic renal masses (mean diameter, 26.5 mm) underwent TAE using a mixture of absolute ethanol and iodized oil to improve visualization of small and endophytic renal masses on unenhanced CT prior to CT-guided PCA. TAE was considered successful that accumulated iodized oil depicted whole of the tumor edge on CT. PCA was considered successful when the iceball covered the entire tumor with over a 5 mm margin. Oncological and renal functional outcomes and complications were also evaluated.ResultsTAE was successfully performed in 16 of 17 endophytic tumors. The 16 tumors were performed under CT-guided PCA with their distinct visualization of localization and safe ablated margin. During the mean follow-up period of 15.4 ± 5.1 months, one patient developed local recurrence. Estimated glomerular filtration rate declined by 8 % with statistical significance (P = 0.01). There was no procedure-related significant complication.ConclusionTAE using a mixture of absolute ethanol and iodized oil to improve visualization of endophytic renal masses facilitated tumor localization on unenhanced CT, permitting depiction of the tumor edge as well as a safe margin for ablation during CT-guided PCA, with an acceptable decline in renal function.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Real-Time Patient and Staff Radiation Dose Monitoring in IR Practice

PurposeKnowledge of medical radiation exposure permits application of radiation protection principles. In our center, the first dedicated real-time, automated patient and staff dose monitoring system (DoseWise Portal, Philips Healthcare) was installed. Aim of this study was to obtain insight in the procedural and occupational doses.Materials and MethodsAll interventional radiologists, vascular surgeons, and technicians wore personal dose meters (PDMs, DoseAware, Philips Healthcare). The dose monitoring system simultaneously registered for each procedure dose-related data as the dose area product (DAP) and effective staff dose (E) from PDMs. Use and type of shielding were recorded separately. All procedures were analyzed according to procedure type; these included among others cerebral interventions (n = 112), iliac and/or caval venous recanalization procedures (n = 68), endovascular aortic repair procedures (n = 63), biliary duct interventions (n = 58), and percutaneous gastrostomy procedure (n = 28).ResultsMedian (±IQR) DAP doses ranged from 2.0 (0.8–3.1) (percutaneous gastrostomy) to 84 (53–147) Gy cm{sup 2} (aortic repair procedures). Median (±IQR) first operator doses ranged from 1.6 (1.1–5.0) μSv to 33.4 (12.1–125.0) for these procedures, respectively. The relative exposure, determined as first operator dose normalized to procedural DAP, ranged from 1.9 in biliary interventions to 0.1 μSv/Gy cm{sup 2} in cerebral interventions, indicating large variation in staff dose per unit DAP among the procedure types.ConclusionReal-time dose monitoring was able to identify the types of interventions with either an absolute or relatively high staff dose, and may allow for specific optimization of radiation protection.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Will X-ray Safety Glasses Become Mandatory for Radiological Vascular Interventions?

PurposeThe annual permissible radiation ocular lens dose has been reduced to 20 millisieverts (mSv) in the current European directive 2013/59/Euratom. The aim of this study was to evaluate the personal radiation dose for vascular interventions with special focus on ocular lens dose.Materials and MethodsFrom May 2016 to October 2016, the personal radiation doses of two interventionists and four technicians were prospectively recorded during 206 vascular interventions. The position of personnel, intervention type and fluoroscopy time were recorded. Parameters evaluated were total body dose measured by film dosimeter, hand dose measured by ring thermoluminescent dosimeter (TLD) and ocular lens dose measured by TLD placed in front of the safety glasses. Linear regression analysis was used to estimate the dose at 2 and 5 years.ResultsThe ocular lens dose, hand and total body dose of the two interventionists were 11/5, 56/47 and 0.6 mSv each, respectively. The estimated 5-year ocular dose was 113.08 mSv (95% CI 38.2–187.97)/40.95 (95% CI 16.9–64.7). Similarly, hand dose was 608.4 mSv (95% CI 442.78–774.38)/514.47 (95% CI 329.83–699.10) and body dose 6.07 mSv (95% CI 4.70–8.22)/5.12 (95% CI 3.65–6.59), respectively. Amongst four technicians, only the first assistant showed recordings of 0.3 mSv body dose, 2 mSv ocular lens dose and 5 mSv hand dose.ConclusionThe yearly ocular lens dose, particularly for interventionists dealing with complex interventions, could cross the permitted yearly limit set by the new Euratom directive. Therefore, X-ray safety glasses would become mandatory for complex radiological vascular interventions.Level of EvidenceLevel III, non-randomized controlled cohort/follow-up study.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

A Very Unlucky Intraoperative Event During a Chimney Technique for Juxtarenal Aneurysm Exclusion

A two-vessel Ch-EVAR procedure was scheduled within the instructions for use of the devices. After deploying, it appeared that the long sheath inserted through an arm access was discovered to be trapped behind the aortic stentgraft barbs. Trying to remove the sheath, the graft was displaced upward and the procedure was converted for a three-vessel Ch-EVAR incorporating the superior mesenteric artery. Simultaneous ballooning of the target vessels and the stentgraft permitted to exert a strong pullback traction on the blocked sheath, allowing its removal. A segment of the sheath distal end was left trapped in the aortic stentgraft. At 12 months follow-up, the patient is free of any complications and there are no occlusions of the abdominal visceral branches or embolic events in peripheral arteries.

62 RADIOLOGY AND NUCLEAR MEDICINE↗