CT Reconstruction using Diffusion Posterior Sampling conditioned on a Nonlinear Measurement Model.

Diffusion models have been demonstrated as powerful deep learning tools for image generation in CT reconstruction and restoration. Recently, diffusion posterior sampling, where a score-based diffusion prior is combined with a likelihood model, has been used to produce high quality CT images given low-quality measurements. This technique is attractive since it permits a one-time, unsupervised training of a CT prior; which can then be incorporated with an arbitrary data model. However, current methods rely on a linear model of x-ray CT physics to reconstruct or restore images. While it is common to linearize the transmission tomography reconstruction problem, this is an approximation to the true and inherently nonlinear forward model. We propose a new method that solves the inverse problem of nonlinear CT image reconstruction via diffusion posterior sampling. We implement a traditional unconditional diffusion model by training a prior score function estimator, and apply Bayes rule to combine this prior with a measurement likelihood score function derived from the nonlinear physical model to arrive at a posterior score function that can be used to sample the reverse-time diffusion process. This plug-and-play method allows incorporation of a diffusion-based prior with generalized nonlinear CT image reconstruction into multiple CT system designs with different forward models, without the need for any additional training. We develop the algorithm that performs this reconstruction, including an ordered-subsets variant for accelerated processing and demonstrate the technique in both fully sampled low dose data and sparse-view geometries using a single unsupervised training of the prior.

Comparison of open and endovascular left subclavian artery revascularization for zone 2 thoracic endovascular aortic repair.

OBJECTIVE: In patients undergoing elective thoracic endovascular aortic repair (TEVAR) and left subclavian artery (LSA) coverage, routine preoperative LSA revascularization is recommended. However, in the current endovascular era, the optimal surgical approach is debated. We compared baseline characteristics, procedural details, and perioperative outcomes of patients undergoing open or endovascular LSA revascularization in the setting of TEVAR. METHODS: Adult patients undergoing TEVAR with zone 2 proximal landing and LSA revascularization between 2013-2023 were identified in the Vascular Quality Initiative. We excluded patients with traumatic aortic injury, aortic thrombus, or ruptured presentations, and stratified based on revascularization type (open vs. any endovascular). Open LSA revascularization included surgical bypass or transposition. Endovascular LSA revascularization included single-branch, fenestration, or parallel stent grafting. Primary outcomes were stroke, spinal cord ischemia, and perioperative mortality (Pearson's χ2-test). Multivariable logistic regression was used to evaluate associations between revascularization type and primary outcomes. Secondarily, we studied other in-hospital complications and 5-year mortality (Kaplan-Meier, multivariable Cox-regression). Sensitivity analysis was performed in patients undergoing concomitant LSA revascularization to TEVAR. RESULTS: Of 2,489 patients, 1,842 (74%) underwent open and 647 (26%) received endovascular LSA revascularization. Demographics and comorbidities were similar between open and endovascular cohorts. Compared with open, endovascular revascularization had shorter procedure times (median 135 vs. 174min, p<.001), longer fluoroscopy time (median 23 vs. 16min, p<.001), lower estimated blood loss (median 100 vs. 123ml, p<.001), and less preoperative spinal drain use (40% vs. 49%, p<.001). Patients undergoing endovascular revascularization were more likely to present urgently (24% vs. 19%) or emergently (7.4% vs. 3.4%) (p<.001). Compared with open, endovascular patients experienced lower stroke rates (2.6% vs. 4.8%, p=.026; aOR 0.50[95%C.I., 0.25-0.90]), but had comparable spinal cord ischemia (2.9% vs. 3.5%, p=.60; 0.64[0.31-1.22]) and perioperative mortality (3.1% vs. 3.3%, p=.94; 0.71[0.34-1.37]). Compared with open, endovascular LSA revascularization had lower rates of overall composite in-hospital complications (20% vs. 27%, p<.001; 0.64[0.49-0.83]) and shorter overall hospital stay (7 vs. 8 days, p<.001). After adjustment, 5-year mortality was similar among groups (aHR 0.85[0.64-1.13]). Sensitivity analysis supported the primary analysis with similar outcomes. CONCLUSIONS: In patients undergoing TEVAR starting in zone 2, endovascular LSA revascularization had lower rates of postoperative stroke and overall composite in-hospital complications, but similar spinal cord ischemia, perioperative and 5-year mortality rates compared with open LSA revascularization. Future comparative studies are needed to evaluate the mid- to long-term safety of endovascular LSA revascularization and assess differences between specific endovascular techniques.

The Association between Sex and Outcomes following Thoracic Endovascular Repair for Acute Type B Aortic Dissection.

OBJECTIVE: Prior literature has found worse outcomes for females following endovascular repair of AAA and mixed findings following TEVAR for TAA. However, the influence of sex on outcomes after TEVAR for acute Type B aortic dissection (aTBAD) is not fully elucidated. METHODS: We identified patients undergoing TEVAR for acute type B aortic dissection (<30 days) in the Vascular Quality Initiative (VQI) from 2014 to 2022. We excluded patients with an entry tear or stent seal within the ascending aorta or aortic arch and patients with an unknown proximal tear location. Included patients were stratified by biological sex, and we analyzed perioperative outcomes and 5-year mortality with multivariable logistic regression and Cox regression analysis, respectively. Furthermore, we analyzed adjusted variables for interaction with female sex. RESULTS: We included 1,626 patients, 33% of whom were female. At presentation, females were significantly older (65 [IQR: 54,75] years vs 56 [IQR: 49,68] years; p= 0.01). Regarding indications for repair, females had higher rates of pain (85% vs 80%; p=0.02), and lower rates of malperfusion (23% vs 35%; p<0.001): specifically mesenteric, renal, and lower limb malperfusion. Females had a lower proportion of proximal repairs in zone 2 (39% vs 48%; p< 0.01). Following TEVAR for aTBAD, female sex was associated with comparable odds of perioperative mortality compared with males (8.1 vs 9.2%; Adjusted Odds Ratio (aOR): 0.79 [95% CI: 0.51-1.20]). Regarding perioperative complications, female sex was associated with lower odds for cardiac complications (2.3% vs 4.7%; aOR: 0.52 [95%CI: 0.26-0.97]), but all other complications were comparable between sexes. Compared with male sex, female sex was associated with similar risk for 5-year mortality (26% vs 23%; Adjusted Hazard Ratio (aHR): 1.01 [95%CI: 0.77-1.32]). Upon testing variables for interaction with sex, female sex was associated with lower perioperative and 5-year mortality at older ages relative to males (aOR: 0.96 [0.93-0.99] | aHR: 0.97 [0.95-0.99]) and higher odds of perioperative mortality when mesenteric malperfusion was present (OR: 2.71 [1.04-6.96]). CONCLUSION: Female patients were older, less likely to have complicated dissection, and had more distal proximal landing zones. Following TEVAR for aTBAD, female sex was associated with similar perioperative and 5-year mortality compared with male sex, but lower odds of in-hospital cardiac complications. Interaction analysis showed females were at additional risk for perioperative mortality when mesenteric ischemia was present. These data suggest that TEVAR for aTBAD overall has a similar safety profile in females as it does for males.

Outcomes of carotid revascularization stratified by procedure in eGFR<30 and dialysis patients.

OBJECTIVE: Renal failure is a predictor of adverse outcomes in carotid revascularization. There has been debate regarding the benefit of revascularization in patients with severe CKD or on dialysis. METHODS: VQI patients undergoing TCAR, tfCAS, or CEA between 2016 and 2023 with eGFR <30 ml/min/1.73m2 or on dialysis were included. Patients were divided into cohorts based on procedure. Additional analyses were performed for patients on dialysis only and by symptomatology. Primary outcomes were perioperative stroke/death/MI (SDM). Secondary outcomes included perioperative death, stroke, MI, CNI and stroke/death. Inverse probability of treatment weighting (IPW) was performed based on treatment assignment to TCAR, tfCAS, and CEA patients and adjusted for demographics, comorbidities, and pre-op symptoms. Chi-square and multivariable logistic regression analysis were used to evaluate the association of procedure with perioperative outcomes in the weighted cohort. Five-year survival was evaluated using Kaplan-Meier and weighted Cox regression. RESULTS: In the weighted cohort, 13,851 patients with eGFR of <30 (2,506 on dialysis) underwent TCAR (3,639, dialysis 704), tfCAS (1,975, 393) or CEA (8,237, 1,409) during the study period. Compared with TCAR, CEA had higher odds of stroke/death/MI (2.8% vs 3.6%, aOR 1.27 [1.00,1.61], p=.049), and MI (0.7% vs 1.5%, aOR 2.00 [1.31,3.05], p=.001)... Compared to TCAR, rates of SDM (2.8%vs5.8%), stroke (1.2%vs2.6%), death (0.9%vs2,4%)were all higher for tfCAS. In asymptomatic patients CEA patients had higher odds of MI (0.7% vs 1.3%, aOR 1.85[1.15, 2.97]p=.011) and CNI (0.3% vs 1.9%, aOR 7.23[3.28, 15.9] p<.001). Like the primary analysis, asymptomatic tfCAS patients demonstrated higher odds of death, and stroke/death. Symptomatic CEA patients demonstrated no difference in stroke, death or stroke/death. While tfCAS patients demonstrated higher odds of death, stroke, MI, stroke/death, and SDM. In both groups, 5-year survival was similar for TCAR and CEA (eGFR <30: 75.1% vs 74.2%, aHR1.06, p=.3) and lower for tfCAS (eGFR <30: 75.1% vs 70.4%, aHR1.44, p<.001) CONCLUSION: CEA and TCAR had similar odds of stroke and death and are both a reasonable choice in this population; however, TCAR may be better in patients with increased risk of MI. Additionally, tfCAS patients were more likely to have worse outcomes after weighting for symptom status. Finally, while patients with reduced eGFR have worse outcomes than their healthy peers, this analysis shows that the majority of patients survive long enough to benefit from the potential stroke risk reduction provided by all revascularization procedures.

Ventral tegmental area interneurons revisited: GABA and glutamate projection neurons make local synapses.

The ventral tegmental area (VTA) contains projection neurons that release the neurotransmitters dopamine, GABA, and/or glutamate from distal synapses. VTA also contains GABA neurons that synapse locally on to VTA dopamine neurons, synapses widely credited to a population of so-called VTA interneurons. Interneurons in cortex, striatum, and elsewhere have well-defined morphological features, physiological properties, and molecular markers, but such features have not been clearly described in VTA. Indeed, there is scant evidence that local and distal synapses originate from separate populations of VTA GABA neurons. In this study we tested whether several markers expressed in non-dopamine VTA neurons are selective markers of interneurons, defined as neurons that synapse locally but not distally. Challenging previous assumptions, we found that VTA neurons genetically defined by expression of parvalbumin, somatostatin, neurotensin, or mu-opioid receptor project to known VTA targets including nucleus accumbens, ventral pallidum, lateral habenula, and prefrontal cortex. Moreover, we provide evidence that VTA GABA and glutamate projection neurons make functional inhibitory or excitatory synapses locally within VTA. These findings suggest that local collaterals of VTA projection neurons could mediate functions prior attributed to VTA interneurons. This study underscores the need for a refined understanding of VTA connectivity to explain how heterogeneous VTA circuits mediate diverse functions related to reward, motivation, or addiction.

Lifelike PixelPrint phantoms for assessing clinical image quality and dose reduction capabilities of a deep learning CT reconstruction algorithm.

Deep learning CT reconstruction (DLR) has become increasingly popular as a method for improving image quality and reducing radiation exposure. Due to their nonlinear nature, these algorithms result in resolution and noise performance which are object-dependent. Therefore, traditional CT phantoms, which lack realistic tissue morphology, have become inadequate for assessing clinical imaging performance. We propose to utilize 3D-printed PixelPrint phantoms, which exhibit lifelike attenuation profiles, textures, and structures, as a better tool for evaluating DLR performance. In this study, we evaluate a DLR algorithm (Precise Image (PI), Philips Healthcare) using a custom PixelPrint lung phantom and perform head-to-head comparisons between DLR, iterative reconstruction, and filtered back projection (FBP) with scans acquired at a broad range of radiation exposures (CTDIvol: 0.5, 1, 2, 4, 6, 9, 12, 15, 19, and 20 mGy). We compared the performance of each resultant image using noise, peak signal to noise ratio (PSNR), structural similarity index (SSIM), feature-based similarity index (FSIM), information theoretic-based statistic similarity measure (ISSM) and universal image quality index (UIQ). Iterative reconstruction at 9 mGy matches the image quality of FBP at 12 mGy (diagnostic reference level) for all metrics, demonstrating a dose reduction capability of 25%. Meanwhile, DLR matches the image quality of diagnostic reference level FBP images at doses between 4 - 9 mGy, demonstrating dose reduction capabilities between 25% and 67%. This study shows that DLR allows for reduced radiation dose compared to both FBP and iterative reconstruction without compromising image quality. Furthermore, PixelPrint phantoms offer more realistic testing conditions compared to traditional phantoms in the evaluation of novel CT technologies. This, in turn, promotes the translation of new technologies, such as DLR, into clinical practice.

MFN2 coordinates mitochondria motility with α-tubulin acetylation and this regulation is disrupted in CMT2A.

Mitofusin-2 (MFN2), a large GTPase residing in the mitochondrial outer membrane and mutated in Charcot-Marie-Tooth type 2 disease (CMT2A), is a regulator of mitochondrial fusion and tethering with the ER. The role of MFN2 in mitochondrial transport has however remained elusive. Like MFN2, acetylated microtubules play key roles in mitochondria dynamics. Nevertheless, it is unknown if the α-tubulin acetylation cycle functionally interacts with MFN2. Here, we show that mitochondrial contacts with microtubules are sites of α-tubulin acetylation, which occurs through MFN2-mediated recruitment of α-tubulin acetyltransferase 1 (ATAT1). This activity is critical for MFN2-dependent regulation of mitochondria transport, and axonal degeneration caused by CMT2A MFN2 associated R94W and T105M mutations may depend on the inability to release ATAT1 at sites of mitochondrial contacts with microtubules. Our findings reveal a function for mitochondria in α-tubulin acetylation and suggest that disruption of this activity plays a role in the onset of MFN2-dependent CMT2A.

Predictors of prolonged length of stay after elective carotid revascularization.

OBJECTIVE: Postoperative day-one discharge is used as a quality-of-care indicator after carotid revascularization. This study identifies predictors of prolonged length of stay (pLOS), defined as a postprocedural LOS of >1 day, after elective carotid revascularization. METHODS: Patients undergoing carotid endarterectomy (CEA), transcarotid artery revascularization (TCAR), and transfemoral carotid artery stenting (TFCAS) in the Vascular Quality Initiative between 2016 and 2022 were included in this analysis. Multivariable logistic regression analysis was used to identify predictors of pLOS, defined as a postprocedural LOS of >1 day, after each procedure. RESULTS: A total of 118,625 elective cases were included. pLOS was observed in nearly 23.2% of patients undergoing carotid revascularization. Major adverse events, including neurological, cardiac, infectious, and bleeding complications, occurred in 5.2% of patients and were the most significant contributor to pLOS after the three procedures. Age, female sex, non-White race, insurance status, high comorbidity index, prior ipsilateral CEA, non-ambulatory status, symptomatic presentation, surgeries occurring on Friday, and postoperative hypo- or hypertension were significantly associated with pLOS across all three procedures. For CEA, additional predictors included contralateral carotid artery occlusion, preoperative use of dual antiplatelets and anticoagulation, low physician volume (<11 cases/year), and drain use. For TCAR, preoperative anticoagulation use, low physician case volume (<6 cases/year), no protamine use, and post-stent dilatation intraoperatively were associated with pLOS. One-year analysis showed a significant association between pLOS and increased mortality for all three procedures; CEA (hazard ratio [HR],1.64; 95% confidence interval [CI], 1.49-1.82), TCAR (HR,1.56; 95% CI, 1.35-1.80), and TFCAS (HR, 1.33; 95%CI, 1.08-1.64) (all P < .05). CONCLUSIONS: A postoperative LOS of more than 1 day is not uncommon after carotid revascularization. Procedure-related complications are the most common drivers of pLOS. Identifying patients who are risk for pLOS highlights quality improvement strategies that can optimize short and 1-year outcomes of patients undergoing carotid revascularization.

Older Chinese and Filipino American Immigrants with Type 2 Diabetes and their Adult Child: A Qualitative Dyadic Exploration of Family Support.

Type 2 Diabetes (T2D) among older Asian American immigrants (AA) is a growing concern. Asian Americans represent 9% of diagnosed diabetes. Very little is known on how older Asian American immigrants with T2D navigate diabetes management, in particular the role of family support. This qualitative study examines Chinese and Filipino Americans, the two largest Asian subgroups in the US (4.2 million, and 3.6 million, respectively), and family support dynamics among adult children and their parents diagnosed with T2D. Ten dyads (n = 20) made up of adult children and aging parents participated in in-depth and dyadic interviews. Results indicate that family support occurs in a trajectory of stages. The following thematic patterns emerged in these dyads around support: independence, transitions, partnership, and stepping in. The findings point to various supportive stages that Asian American adult children and aging parents with T2D experience and the importance of developing supportive interventions for both adult children and aging parents at these various stages.

Hybrid spectral CT system with clinical rapid kVp-switching x-ray tube and dual-layer detector for improved iodine quantification.

Spectral computed tomography (CT) is a powerful diagnostic tool offering quantitative material decomposition results that enhance clinical imaging by providing physiologic and functional insights. Iodine, a widely used contrast agent, improves visualization in various clinical contexts. However, accurately detecting low-concentration iodine presents challenges in spectral CT systems, particularly crucial for conditions like pancreatic cancer assessment. In this study, we present preliminary results from our hybrid spectral CT instrumentation which includes clinical-grade hardware (rapid kVp-switching x-ray tube, dual-layer detector). This combination expands spectral datasets from two to four channels, wherein we hypothesize improved quantification accuracy for low-dose and low-iodine concentration cases. We modulate the system duty cycle to evaluate its impact on quantification noise and bias. We evaluate iodine quantification performance by comparing two hybrid weighting strategies alongside rapid kVp-switching. This evaluation is performed with a polyamide phantom containing seven iodine inserts ranging from 0.5 to 20 mg/mL. In comparison to alternative methodologies, the maximum separation configuration, incorporating data from both the 80 kVp, low photon energy detector layer and the 140 kVp, high photon energy detector layer produces spectral images containing low quantitative noise and bias. This study presents initial evaluations on a hybrid spectral CT system, leveraging clinical hardware to demonstrate the potential for enhanced precision and sensitivity in spectral imaging. This research holds promise for advancing spectral CT imaging performance across diverse clinical scenarios.

Seven years of the transcarotid artery revascularization surveillance project, comparison to transfemoral stenting and endarterectomy.

OBJECTIVE: This study utilizes the latest data from the Vascular Quality Initiative (VQI), which now encompasses over 50,000 transcarotid artery revascularization (TCAR) procedures, to offer a sizeable dataset for comparing the effectiveness and safety of TCAR, transfemoral carotid artery stenting (tfCAS), and carotid endarterectomy (CEA). Given this substantial dataset, we are now able to compare outcomes overall and stratified by symptom status across revascularization techniques. METHODS: Utilizing VQI data from September 2016 to August 2023, we conducted a risk-adjusted analysis by applying inverse probability of treatment weighting to compare in-hospital outcomes between TCAR vs tfCAS, CEA vs tfCAS, and TCAR vs CEA. Our primary outcome measure was in-hospital stroke/death. Secondary outcomes included myocardial infarction and cranial nerve injury. RESULTS: A total of 50,068 patients underwent TCAR, 25,361 patients underwent tfCAS, and 122,737 patients underwent CEA. TCAR patients were older, more likely to have coronary artery disease, chronic kidney disease, and undergo coronary artery bypass grafting/percutaneous coronary intervention as well as prior contralateral CEA/CAS compared with both CEA and tfCAS. TfCAS had higher odds of stroke/death when compared with TCAR (2.9% vs 1.6%; adjusted odds ratio [aOR], 1.84; 95% confidence interval [CI], 1.65-2.06; P < .001) and CEA (2.9% vs 1.3%; aOR, 2.21; 95% CI, 2.01-2.43; P < .001). CEA had slightly lower odds of stroke/death compared with TCAR (1.3% vs 1.6%; aOR, 0.83; 95% CI, 0.76-0.91; P < .001). TfCAS had lower odds of cranial nerve injury compared with TCAR (0.0% vs 0.3%; aOR, 0.00; 95% CI, 0.00-0.00; P < .001) and CEA (0.0% vs 2.3%; aOR, 0.00; 95% CI, 0.0-0.0; P < .001) as well as lower odds of myocardial infarction compared with CEA (0.4% vs 0.6%; aOR, 0.67; 95% CI, 0.54-0.84; P < .001). CEA compared with TCAR had higher odds of myocardial infarction (0.6% vs 0.5%; aOR, 1.31; 95% CI, 1.13-1.54; P < .001) and cranial nerve injury (2.3% vs 0.3%; aOR, 9.42; 95% CI, 7.78-11.4; P < .001). CONCLUSIONS: Although tfCAS may be beneficial for select patients, the lower stroke/death rates associated with CEA and TCAR are preferred. When deciding between CEA and TCAR, it is important to weigh additional procedural factors and outcomes such as myocardial infarction and cranial nerve injury, particularly when stroke/death rates are similar. Additionally, evaluating subgroups that may benefit from one procedure over another is essential for informed decision-making and enhanced patient care in the treatment of carotid stenosis.

Foraging behaviour and habitat use during chick-rearing in the Australian endemic black-faced cormorant (Phalacrocorax fuscescens).

Despite its wide distribution, relatively little is known of the foraging ecology and habitat use of the black-faced cormorant (Phalacrocorax fuscescens), an Australian endemic seabird. Such information is urgently required in view of the rapid oceanic warming of south-eastern Australia, the stronghold of the species. The present study used a combination of opportunistically collected regurgitates and GPS/dive behaviour data loggers to investigate diet, foraging behaviour and habitat-use of black-faced cormorants during four chick-rearing periods (2020-2023) on Notch Island, northern Bass Strait. Observed prey species were almost exclusively benthic (95%), which is consistent with the predominantly benthic diving behaviour recorded. Males foraged at deeper depths than females (median depth males: 18 m; median depth females: 8 m), presumably due to a greater physiological diving capacity derived from their larger body size. This difference in dive depths was associated with sexual segregation of foraging locations, with females predominantly frequenting shallower areas closer to the coastline. These findings have strong implications for the management of the species, as impacts of environmental change may disproportionally affect the foraging range of one sex and, thereby, reproductive success.

Endovascular Inferior Vena Cava Filters Placed in Duplicated Inferior Vena Cava Syndrome.

Duplicated inferior vena cava (D-IVC) is a relatively rare anatomical anomaly. Clinically, these anomalies are incidentally found on computed tomography (CT) or magnetic resonance imaging (MRI). Lack of pre-operative identification of this congenital malformation can lead to incomplete protection against thromboembolism or hemorrhage. We present a case of a 71-year-old male with a duplicated inferior vena cava who underwent insertion of bilateral inferior vena cava filters for deep vein thrombosis (DVT) management.

A bioinformatic analysis of T-cell epitope diversity in SARS-CoV-2 variants: association with COVID-19 clinical severity in the United States population.

Long-term immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires the identification of T-cell epitopes affecting host immunogenicity. In this computational study, we explored the CD8+ epitope diversity estimated in 27 of the most common HLA-A and HLA-B alleles, representing most of the United States population. Analysis of 16 SARS-CoV-2 variants [B.1, Alpha (B.1.1.7), five Delta (AY.100, AY.25, AY.3, AY.3.1, AY.44), and nine Omicron (BA.1, BA.1.1, BA.2, BA.4, BA.5, BQ.1, BQ.1.1, XBB.1, XBB.1.5)] in analyzed MHC class I alleles revealed that SARS-CoV-2 CD8+ epitope conservation was estimated at 87.6%-96.5% in spike (S), 92.5%-99.6% in membrane (M), and 94.6%-99% in nucleocapsid (N). As the virus mutated, an increasing proportion of S epitopes experienced reduced predicted binding affinity: 70% of Omicron BQ.1-XBB.1.5 S epitopes experienced decreased predicted binding, as compared with ~3% and ~15% in the earlier strains Delta AY.100-AY.44 and Omicron BA.1-BA.5, respectively. Additionally, we identified several novel candidate HLA alleles that may be more susceptible to severe disease, notably HLA-A*32:01, HLA-A*26:01, and HLA-B*53:01, and relatively protected from disease, such as HLA-A*31:01, HLA-B*40:01, HLA-B*44:03, and HLA-B*57:01. Our findings support the hypothesis that viral genetic variation affecting CD8 T-cell epitope immunogenicity contributes to determining the clinical severity of acute COVID-19. Achieving long-term COVID-19 immunity will require an understanding of the relationship between T cells, SARS-CoV-2 variants, and host MHC class I genetics. This project is one of the first to explore the SARS-CoV-2 CD8+ epitope diversity that putatively impacts much of the United States population.

Retrograde pedal access and percutaneous mechanical thrombectomy for salvage of an occluded vein bypass.

Managing occlusions in a lower extremity bypass is challenging, although several surgical methods and percutaneous devices are available for treatment. A 64-year-old man presented with subacute failure of his infrainguinal vein bypass. Because we were unable to access the bypass in an antegrade fashion, we accessed the bypass graft via retrograde pedal access. The occluded vein graft was salvaged with the Pounce percutaneous mechanical thrombectomy system (Surmodics) with the use of a 0.014-in. through and through buddy wire to maintain access in the bypass alongside the Pounce system to allow multiple passes of the nitinol baskets to retrieve thrombus.

Association Between Diagnosis-to-Limb Revascularization Time and Clinical Outcomes in Outpatients With Chronic Limb-Threatening Ischemia: Insights From the CLIPPER Cohort.

BACKGROUND: The extent and consequences of ischemia in patients with chronic limb-threatening ischemia (CLTI) may change rapidly, and delays from diagnosis to revascularization may worsen outcomes. We sought to describe the association between time from diagnosis to endovascular lower extremity revascularization (diagnosis-to-limb revascularization [D2L] time) and clinical outcomes in outpatients with CLTI. METHODS AND RESULTS: In the CLIPPER cohort, comprising patients between 66 and 86 years old diagnosed with CLTI betweeen 2010 and 2019, we used Medicare claims data to identify patients who underwent outpatient endovascular revascularization within 180 days of diagnosis. We described the risk-adjusted association between D2L time and clinical outcomes. Among 1 130 065 patients aged between 66 and 86 years with CLTI, 99 221 (8.8%) underwent outpatient endovascular lower extremity revascularization within 180 days of their CLTI diagnosis. Among patients with D2L time <30 days, there was no association between D2L time and all-cause death or major lower extremity amputation. However, among patients with D2L time >30 days, each additional 10-day increase in D2L time was associated with a 2.5% greater risk of major amputation (hazard ratio, 1.025 [95% CI, 1.014-1.036]). There was no association between D2L time and all-cause death. CONCLUSIONS: A delay of >30 days from CLTI diagnosis to lower extremity endovascular revascularization was associated with an increased risk of major lower extremity amputation among patients undergoing outpatient endovascular revascularization. Improving systems of care to reduce D2L time could reduce amputations.

Carriage of antimicrobial-resistant Enterobacterales among pregnant women and newborns in Amhara, Ethiopia.

OBJECTIVES: Infections are one of the most common causes of neonatal mortality, and maternal colonization has been associated with neonatal infection. In this study, we sought to quantify carriage prevalence of extended-spectrum-beta-lactamase (ESBL) -producing and carbapenem-resistant Enterobacterales (CRE) among pregnant women and their neonates and to characterize risk factors for carriage in rural Amhara, Ethiopia. METHODS: We conducted a prospective cohort study nested in the Birhan field site. We collected rectal and vaginal samples from 211 pregnant women in their third trimester and/or during labor/delivery and perirectal or stool samples from 159 of their neonates in the first week of life. RESULTS: We found that carriage of ESBL-producing organisms was fairly common (women: 22.3%, 95% CI: 16.8-28.5; neonates: 24.5%, 95% CI: 18.1-32.0), while carriage of CRE (women: 0.9%, 95% CI: 0.1-3.4; neonates: 2.5%, 95% CI: 0.7-6.3) was rare. Neonates whose mothers tested positive for ESBL-producing organisms were nearly twice as likely to also test positive for ESBL-producing organisms (38.7% vs 21.1%, P-value = 0.06). Carriage of ESBL-producing organisms was also associated with Woreda (district) of sample collection and recent antibiotic use. CONCLUSION: Understanding carriage patterns of potential pathogens and antibiotic susceptibility among pregnant women and newborns will inform local, data-driven recommendations to prevent and treat neonatal infections.

Factors Associated with Urgent Amputation Status and Its Impact on Mortality.

BACKGROUND: Thirty-day mortality is higher after urgent major lower extremity amputations compared to elective lower extremity amputations. This study aims to identify factors associated with urgent amputations and to examine their impact on perioperative outcomes and long-term mortality. METHODS: Patients undergoing major lower limb amputation from 2013 to 2020 in the Vascular Quality Initiative were included. Urgent amputation was defined as occurring within 72 hr of admission. Associations with sociodemographic characteristics, comorbidities, and outcomes including postoperative complication, inpatient death, and long-term survival were compared using univariable tests and multivariable logistic regression. Long-term survival between groups was compared using Kaplan-Meier analysis. RESULTS: Of the 12,874 patients included, 4,850 (37.7%) had urgent and 8,024 (62.3%) had elective amputations. Non-White patients required urgent amputation more often than White patients (39.8% vs. 37.9%, P = 0.03). A higher proportion of Medicaid and self-pay patients presented urgently (Medicaid: 13.0% vs. 11.0%; self-pay: 3.4% vs. 2.5%, P < 0.001). Patients requiring urgent amputation were less often taking aspirin (55.6% vs. 60.1%, P < 0.001) or statin (62.2% vs. 67.2%, P < 0.001), had fewer prior revascularization procedures (41.0% vs. 48.8%, P < 0.001), and were of higher American Society of Anesthesiologists (ASA) class 4-5 (50.9% vs. 40.1%, P < 0.001). Urgent amputations were more commonly for uncontrolled infection (48.1% vs. 29.4%, P < 0.001) or acute limb ischemia (14.3% vs. 6.2%, P < 0.001). Postoperative complications were higher after urgent amputations (34.7% vs. 16.6%, P < 0.001), including need for return to operating room (23.8% vs. 8.4%, P < 0.001) and need for higher revision (15.2% vs. 4.5%, P < 0.001). Inpatient mortality was higher after urgent amputation (8.9% vs. 5.4%, P < 0.001). Multivariable analysis revealed non-White race, self-pay, homelessness, current smoking, ASA class 4-5, and amputations for uncontrolled infection or acute limb ischemia were associated with urgent status, whereas living in a nursing home or prior revascularization were protective. Furthermore, urgent amputation was associated with an increased odds of postoperative complication or death (odds ratio 1.86 [1.69-2.04], P < 0.001) as well as long-term mortality (odds ratio: 1.24 [1.13-1.35], P < 0.001). Kaplan-Meier analysis corroborated that elective status was associated with improvement of long-term survival. CONCLUSIONS: Patients requiring urgent amputations are more often non-White, uninsured, and less frequently had prior revascularization procedures, revealing disparities in access to care. Urgency was associated with a higher postoperative complication rate, as well as increased long-term mortality. Efforts should be directed toward reducing these disparities to improve outcomes following amputation.

Fully automatic online geometric calibration for non-circular cone-beam CT orbits using fiducials with unknown placement.

BACKGROUND: Cone-beam CT (CBCT) with non-circular scanning orbits can improve image quality for 3D intraoperative image guidance. However, geometric calibration of such scans can be challenging. Existing methods typically require a prior image, specialized phantoms, presumed repeatable orbits, or long computation time. PURPOSE: We propose a novel fully automatic online geometric calibration algorithm that does not require prior knowledge of fiducial configuration. The algorithm is fast, accurate, and can accommodate arbitrary scanning orbits and fiducial configurations. METHODS: The algorithm uses an automatic initialization process to eliminate human intervention in fiducial localization and an iterative refinement process to ensure robustness and accuracy. We provide a detailed explanation and implementation of the proposed algorithm. Physical experiments on a lab test bench and a clinical robotic C-arm scanner were conducted to evaluate spatial resolution performance and robustness under realistic constraints. RESULTS: Qualitative and quantitative results from the physical experiments demonstrate high accuracy, efficiency, and robustness of the proposed method. The spatial resolution performance matched that of our existing benchmark method, which used a 3D-2D registration-based geometric calibration algorithm. CONCLUSIONS: We have demonstrated an automatic online geometric calibration method that delivers high spatial resolution and robustness performance. This methodology enables arbitrary scan trajectories and should facilitate translation of such acquisition methods in a clinical setting.

Patient-derived PixelPrint phantoms for evaluating clinical imaging performance of a deep learning CT reconstruction algorithm.

Objective. Deep learning reconstruction (DLR) algorithms exhibit object-dependent resolution and noise performance. Thus, traditional geometric CT phantoms cannot fully capture the clinical imaging performance of DLR. This study uses a patient-derived 3D-printed PixelPrint lung phantom to evaluate a commercial DLR algorithm across a wide range of radiation dose levels.Method. The lung phantom used in this study is based on a patient chest CT scan containing ground glass opacities and was fabricated using PixelPrint 3D-printing technology. The phantom was placed inside two different size extension rings to mimic a small- and medium-sized patient and was scanned on a conventional CT scanner at exposures between 0.5 and 20 mGy. Each scan was reconstructed using filtered back projection (FBP), iterative reconstruction, and DLR at five levels of denoising. Image noise, contrast to noise ratio (CNR), root mean squared error, structural similarity index (SSIM), and multi-scale SSIM (MS SSIM) were calculated for each image.Results.DLR demonstrated superior performance compared to FBP and iterative reconstruction for all measured metrics in both phantom sizes, with better performance for more aggressive denoising levels. DLR was estimated to reduce dose by 25%-83% in the small phantom and by 50%-83% in the medium phantom without decreasing image quality for any of the metrics measured in this study. These dose reduction estimates are more conservative compared to the estimates obtained when only considering noise and CNR.Conclusion. DLR has the capability of producing diagnostic image quality at up to 83% lower radiation dose, which can improve the clinical utility and viability of lower dose CT scans. Furthermore, the PixelPrint phantom used in this study offers an improved testing environment with more realistic tissue structures compared to traditional CT phantoms, allowing for structure-based image quality evaluation beyond noise and contrast-based assessments.