Comparative Evaluation of Lower Gadolinium Doses for MR Imaging of Meningiomas: How Low Can We Go?

BACKGROUND AND PURPOSE: Gadolinium-based contrast agents are widely used for meningioma imaging; however, concerns exist regarding their side effects, cost, and environmental impact. At the standard gadolinium dose, most meningiomas show avid contrast enhancement suggesting that administering a smaller dose may be feasible. The purpose of this study was to evaluate the impact of a lower gadolinium dose on the differentiation between meningiomas and adjacent intracranial tissues. MATERIALS AND METHODS: 108 patients with presumed or confirmed meningiomas who underwent brain MRI at multiple doses of gadolinium were included in the study. The patients' MRIs were categorized into three groups based on the gadolinium dose administered: Micro (approximately 25% of the standard dose), Low (approximately 62% of the standard dose) and Standard dose. Multi-reader qualitative visual assessment and quantitative relative signal differences calculations were performed to evaluate tumor differentiation from the cortex and from the dural venous sinus. The relative signal differences for each dose were analyzed using ANOVA for quantitative assessment and NcNemar for qualitative assessment. Additionally, non-inferiority testing was used to compare the Low and Micro doses to the Standard dose. RESULTS: Decreasing the gadolinium dose to a Low dose or a Micro dose resulted in a statistically significant decrease in signal difference between the tumor and the adjacent brain tissues (p<0.02). However, on visual assessment, the Low dose was non-inferior to the Standard dose. The proportion of cases with suboptimal differentiation was significantly higher for the Micro dose than for the Standard dose, both for the differentiation between the tumor and the cortex (p=0.041) and the differentiation between tumor and sinus (p<0.001). CONCLUSIONS: Reducing the gadolinium dose to 62% of the standard level still allows for sufficient visual delineation of meningiomas from surrounding tissues. However, further reduction to 25% substantially compromises the ability to distinguish the tumor from adjacent structures and is, therefore, not advisable. ABBREVIATIONS: GBCAs = Gadolinium-based contrast agents; SSS = Superior Sagittal Sinus.

Heart rate variability-based prediction of early cardiotoxicity in breast-cancer patients treated with anthracyclines and trastuzumab.

BACKGROUND: Cardiotoxicity is a recognized complication in breast cancer (BC) patients undergoing chemotherapy with anthracyclines with or without trastuzumab. However, the prognostic value of heart rate variability (HRV) indexes for early cardiotoxicity development remains unknown. METHODS: Fifty BC patients underwent TTE assessment before and three months after chemotherapy. HRV indexes were obtained from continuous electrocardiograms in supine position with spontaneous breathing, active standing, and supine position with controlled breathing. The magnitude of change (Δ) between supine-standing and supine-controlled breathing was calculated. Variables were compared using t-test or ANOVA. Cardiotoxicity predictive value was assessed by ROC curve analysis. A p value of < 0.05 was considered significant. RESULTS: TTE revealed reduced left atrial conduit strain in the cardiotoxicity group. Mean heart rate increased during all maneuvers at follow-up, with no differences in HRV indexes between patients with or without cardiotoxicity. However, a lower Δ in supine-controlled breathing of several HRV indexes predicted early cardiotoxicity identified by echocardiography (e.g. SDNN ≤ -8.44 ms: Sensitivity = 75%, Specificity = 69%). CONCLUSIONS: BC patients treated with chemotherapy maintain cardiac autonomic responses to physiological stimuli after 3 months of chemotherapy. However, a lower Δ during active standing and controlled breathing before chemotherapy may predict early cardiotoxicity.

Monitoring the Velocity of Domain Wall Motion in Magnetic Microwires.

An approach was proposed to control the displacement of domain walls in magnetic microwires, which are employed in magnetic sensors. The velocity of the domain wall can be altered by the interaction of two magnetic microwires of distinct types. Thorough investigations were conducted utilizing fluxmetric, Sixtus-Tonks, and magneto-optical techniques. The magneto-optical examinations revealed transformation in the surface structure of the domain wall and facilitated the determination of the mechanism of external influence on the movement of domain walls in magnetic microwires.

Podoconiosis.

This case report describes a woman with the appearance of elephantine skin tumors predominantly on her left foot.

Enfrentamiento ante filtraciones de la esófagoyeyuno anastomosis

La filtración de la esófagoyeyuno anastomosis (FEYA) es una de las complicaciones más graves tras una gastrectomía total, ya que se asocia a un aumento de la morbimortalidad quirúrgica. El manejo óptimo de la FEYA aún es controversial, existiendo cada vez más opciones mínimamente invasivas, especialmente endoscópicas. El objetivo de la presente revisión es comparar la evidencia científica publicada y actualizada referente al tratamiento médico, endoscópico y quirúrgico de una FEYA y sus resultados a corto y largo plazo además de proponer un algoritmo de manejo que permita orientar la práctica clínica. Finalmente se presenta la experiencia nacional en relación a los avances presentados en los últimos años en torno manejo clínico de FEYA.

Leakage of the esophagojejunostomy (LEY) is one of the most serious complications after total gastrectomy, as it is associated with increased surgical morbidity and mortality. The optimal management of LEY is still controversial, with increasing minimally invasive options, especially endoscopic ones. The aim of this review is to compare the published and updated scientific evidence regarding the medical, endoscopic and surgical treatment of LEY and its short and long-term results, in addition to propose a management algorithm that allows guiding clinical practice. Finally, the national experience is presented in relation to the advances presented in recent years regarding clinical management of LEY.

Anomalous Magnetic Anisotropy Behaviour in Co-Rich and Fe-Rich Glass-Coated Microwires under Applied Stress.

In this article, we study the effect of annealing temperature and applied stress on the magnetic properties of Fe71.80B13.27Si11.02Nb2.99Ni0.92 and Co65.34Si12.00B10.20Cr8.48Fe3.90Mo0.08 microwires. An anomalous behavior of the coercive field is observed while applying stress, indicating nontrivial changes in the microwire magnetic anisotropy. The effect of applied stimuli on the magnetic anisotropy and magnetostriction constant in both microwires is also discussed.

Bariatric Surgery Before and After the SARS-CoV-2 Pandemic: a Comparative Study of Cases Before the Onset of the Pandemic in a High-Volume Academic Center.

INTRODUCTION: At the beginning of the pandemic, studies showed a higher risk of severe surgical complications and mortality among patients with perioperative SARS-CoV-2 infection, which led to the suspension of elective surgery. Confinement and lockdown measures were shown to be associated with weight gain and less access to medical and surgical care in patients with obesity, with negative health consequences. To evaluate the safety of bariatric surgery during the pandemic, we compared 30-day complications between patients who underwent bariatric surgery immediately before with those who underwent bariatric surgery during the opening phase of the pandemic. METHODS: Observational analytical study of a non-concurrent cohort of patients who underwent bariatric surgery in 2 periods: pre-pandemic March 1 to December 31, 2019, and pandemic March 1 to December 31, 2020. Surgical complications were defined using the Clavien-Dindo classification. RESULTS: Pre-pandemic and pandemic groups included 256 and 202 patients who underwent primary bariatric surgery, respectively. The mean age was 37.6 + 10.3 years. The overall complication rate during the first 30 days of discharge was 7.42%. No differences between groups were observed in severe complications (pre-pandemic 1.56% vs. pandemic 1.98%, p: 0.58). No mortality was reported. Overall 30-day readmission was 3.28% with no differences between groups. CONCLUSION: The findings of this study did not find a difference in the rate of severe complications, nor also we report severe COVID-19 complications in this high-risk population. During the pandemic, with appropriately implemented protocol, the resumption of bariatric surgery is possible with no increased risk for patients.

Comparison of clinically available dynamic susceptibility contrast post processing software to differentiate progression from pseudoprogression in post-treatment high grade glioma.

INTRODUCTION: The purpose of this retrospective study was to compare two, widely available software packages for calculation of Dynamic Susceptibility Contrast (DSC) perfusion MRI normalized relative Cerebral Blood Volume (rCBV) values to differentiate tumor progression from pseudoprogression in treated high-grade glioma patients. MATERIAL AND METHODS: rCBV maps processed by Siemens Syngo.via (Siemens Healthineers) and Olea Sphere (Olea Medical) software packages were co-registered to contrast-enhanced T1 (T1-CE). Regions of interest based on T1-CE were transferred to the rCBV maps. rCBV was calculated using mean values and normalized using contralateral normal- appearing white matter. The Wilcoxon test was performed to assess for significant differences, and software-specific optimal rCBV cutoff values were determined using the Youden index. Interrater reliability was evaluated for two raters using the intraclass correlation coefficient. RESULTS: 41 patients (18 females; median age = 59 years; range 21-77 years) with 49 new or size-increasing post-treatment contrast-enhancing lesions were included (tumor progression = 40 lesions; pseudoprogression = 9 lesions). Optimal rCBV cutoffs of 1.31 (Syngo.via) and 2.40 (Olea) were significantly different, with an AUC of 0.74 and 0.78, respectively. Interrater reliability was 0.85. DISCUSSION: We demonstrate that different clinically available MRI DSC-perfusion software packages generate significantly different rCBV cutoff values for the differentiation of tumor progression from pseudoprogression in standard-of-care treated high grade gliomas. Physicians may want to determine the unique value of their perfusion software packages on an institutional level in order to maximize diagnostic accuracy when faced with this clinical challenge. Furthermore, combined with implementation of current DSC-perfusion recommendations, multi-center comparability will be improved.

Optimization of Magnetoimpedance Effect and Magnetic Properties of Fe-Rich Glass-Coated Microwires by Annealing.

As-prepared Fe-rich microwires with perfectly rectangular hysteresis loops present magnetization reversal through fast domain wall propagation, while the giant magnetoimpedance (GMI) effect in Fe-rich microwires is rather low. However, the lower cost of Fe-rich microwires makes them attractive for magnetic sensors applications. We studied the effect of conventional (furnace) annealing and Joule heating on magnetic-propertied domain wall (DW) dynamics and the GMI effect in two Fe microwires with different geometries. We observed that magnetic softness, GMI effect and domain wall (DW) dynamics can be substantially improved by appropriate annealing. Observed experimental results are discussed considering the counterbalance between the internal stresses relaxation and induced magnetic anisotropy associated with the presence of an Oersted magnetic field during Joule heating.

Periventricular nodular heterotopia associated with a "transmantle band sign" in patients with epilepsy.

OBJECTIVE: Previous studies using advanced magnetic resonance imaging (MRI) techniques have documented abnormal transmantle bands connecting ectopic nodules to overlying cortex in patients with periventricular nodular heterotopia (PNH). We describe a similar finding using conventional MRI techniques. METHODS: Patients were identified by means of a full-text search of radiological reports. All scanning was performed using conventional sequences at 3 Tesla (3T). Scans were reviewed by three neuroradiologists, and we characterized imaging features based on type of PNH and cortical irregularities associated with the transmantle band. RESULTS: A total 57 PNH patients were reviewed, of whom 41 demonstrated a "transmantle band" connecting the nodule to the overlying cortex. One or more periventricular heterotopic nodules was present in all 41 patients-this was bilateral in 29 of 41 (71%) and unilateral in the remaining 29%. In many cases there was more than one such band, and in some cases this band was nodular. In 19 of the cases, the cortex to which the band connected was abnormal, showing thinning in 4 cases, thickening in 5 cases, and polymicrogyria in another 10. SIGNIFICANCE: The transmantle band can be seen frequently in both unilateral and bilateral cases of PNH and can be visualized with conventional 3T MRI sequences. The band highlights the underlying neuronal migration issues at play in the pathogenesis of this disorder, but its underlying role in the complex, patient-specific epileptogenic networks in this cohort has yet to be determined and warrants further investigation.

Determination of Magnetic Structures in Magnetic Microwires with Longitudinally Distributed Magnetic Anisotropy.

We studied the magnetic properties of a glass-covered amorphous microwire that was stress-annealed at temperatures distributed along the microwire length. The Sixtus-Tonks, Kerr effect microscopy and magnetic impedance techniques have been applied. There was a transformation of the magnetic structure across the zones subjected to annealing at different temperatures. The annealing temperature distribution induces the graded magnetic anisotropy in the studied sample. The variety of the surface domain structures depending on the longitudinal location has been discovered. Spiral, circular, curved, elliptic and longitudinal domain structures coexist and replace each other in the process of magnetization reversal. The analysis of the obtained results was carried out based on the calculations of the magnetic structure, assuming the distribution of internal stresses.

Mechanisms of imbalanced frontostriatal functional connectivity in obsessive-compulsive disorder.

The diagnosis of obsessive-compulsive disorder (OCD) has been linked with changes in frontostriatal resting-state connectivity. However, replication of prior findings is lacking, and the mechanistic understanding of these effects is incomplete. To confirm and advance knowledge on changes in frontostriatal functional connectivity in OCD, participants with OCD and matched healthy controls underwent resting-state functional, structural and diffusion neuroimaging. Functional connectivity changes in frontostriatal systems were here replicated in individuals with OCD (n = 52) compared with controls (n = 45). OCD participants showed greater functional connectivity (t = 4.3, PFWE = 0.01) between the nucleus accumbens (NAcc) and the orbitofrontal cortex (OFC) but lower functional connectivity between the dorsal putamen and lateral prefrontal cortex (t = 3.8, PFWE = 0.04) relative to controls. Computational modelling suggests that NAcc-OFC connectivity changes reflect an increased influence of NAcc over OFC activity and reduced OFC influence over NAcc activity (posterior probability, Pp > 0.66). Conversely, dorsal putamen showed reduced modulation over lateral prefrontal cortex activity (Pp > 0.90). These functional deregulations emerged on top of a generally intact anatomical substrate. We provide out-of-sample replication of opposite changes in ventro-anterior and dorso-posterior frontostriatal connectivity in OCD and advance the understanding of the neural underpinnings of these functional perturbations. These findings inform the development of targeted therapies normalizing frontostriatal dynamics in OCD.

Colecistectomía laparoscópica: técnica por video e-learning

Introducción: La Colecistectomía laparoscópica es una de las cirugías más frecuentes en nuestro país. Diversas dificultades han limitado una buena formación al respecto. Contar con un apoyo educativo capaz de transmitir la experiencia quirúrgica que facilite su aprendizaje, resulta imprescindible. Objetivo: Describir la técnica quirúrgica de una colecistectomía laparoscópica estándar incorporando elementos propios de la decisión quirúrgica, apoyado en tecnología e-learning. Materiales y Método: Estudio descriptivo. Se confeccionó material audiovisual de una colecistectomía laparoscópica, editado con apoyo de dibujo y animación 3D, e incorporando elementos técnicos propios del acto quirúrgico. Finalmente se redactó el texto de la técnica y se enlazó a través de códigos QR a capsulas del material audiovisual confeccionado. Resultados: Cinco pasos descriptivos claves de la colecistectomía laparoscópica apoyados con enlaces directos, tanto a través de un link asociado al texto como a través de una imagen QR anexa, a capsulas audiovisuales con información técnica y estratégica propia del ejercicio quirúrgico intraoperatorio. Conclusión: Técnica quirúrgica de una colecistectomía laparoscópica expuesta paso a paso apoyado con material audiovisual de una forma dinámica e innovadora, basado en nuevas tecnologías facilitadoras del aprendizaje.

Background: The laparoscopic cholecystectomy's technique has a great relevance in training programs. Their teaching requires a methodology that incorporates technical details that are lost with just reading or watching the procedure. Aim: This study presents the description of the surgical steps associated to an anatomical e-learning support that includes strategic and technical elements. Materials and Method: A standard laparoscopic cholecystectomy was used to make an educational video highlighting the critical aspect and concepts of its execution. The video incorporated drawings, painting and animations that fa- cilitate understanding. It was split and linked to Qr codes. Results: The detailed description of the steps of a cholecystectomy, such as a proper exposure of the surgical field, the dissection of the hepatocystic triangle, the safety view or gallbladder release, was associated with a Qr link. Conclusión: A step-by-step laparoscopic cholecystectomy in a dynamic and innovative way with an audiovisual support that facilitate learning.

Quantitative spinal cord MRI and sexual dysfunction in multiple sclerosis.

Background: Sexual dysfunction (SD) is frequently reported in multiple sclerosis (MS) and is likely related to MS-related damage to the spinal cord (SC). Objective: To assess associations between SD and quantitative MRI measures in people with MS (pwMS). Methods: This pilot study included 17 pwMS with SD who completed questionnaires assessing SD, mood, and fatigue. All participants underwent brain, cervical, and thoracic SC-MRI at 3T. Quantitative brain and SC-MRI measures, including brain/SC atrophy, SC lesion count, diffusion-tensor imaging (DTI) indices (fractional anisotropy [FA], mean, perpendicular, parallel diffusivity [MD, λ⊥, λ||]) and magnetization-transfer ratio (MTR) were obtained. Associations between quantitative MRI measures and SD were assessed while controlling for the extent of mood and fatigue symptomatology. Results: Subjects were a mean age of 46.9 years and 29% female. All subjects had self-reported SD (MSISQ-19 = 40.7, SQoL: 55.9) and 65% had a concurrent psychiatric diagnosis. When correlations between SD severity were assessed with individual brain and SC-MRI measures while controlling for psychiatric symptomatology, no associations were found. The only variables showing independent associations with SD were anxiety (p = 0.03), depression (p = 0.05), and fatigue (p = 0.04). Conclusion: We found no correlations between quantitative MRI measures in the brain and SC and severity of SD in pwMS, but psychiatric symptomatology and fatigue severity demonstrated relationships with SD. The multifactorial nature of SD in pwMS mandates a multidisciplinary approach.

Progressive Supranuclear Palsy Syndrome Associated With a Novel Tauopathy: Case Study.

OBJECTIVES: To report a novel tauopathy in a patient with protracted coursed progressive supranuclear palsy (PC-PSP). METHODS: Clinical follow-up, gene analysis, neuropathological study. RESULTS: A 73-year-old man presented with diplopia, slowness, shuffling gait and falls. Neurological examination revealed slowed saccades, restricted up-gaze and mild parkinsonism. Three years after onset he developed personality changes. Slowly progressive parkinsonism was associated with memory and executive deficits. MRI showed subtle bilateral hippocampal and midbrain tegmentum atrophy and hyper-intensity in the brainstem tegmentum and white matter of the medial temporal lobe. Duration of illness was 11 years. There were no pathogenic mutations in 80 genes known to be involved in neurodegeneration, including MAPT (H1/H1 haplotype) and APOE (ε3/ε3 genotype). Neuropathology revealed PSP type pathology together with the pathology described in the novel limbic-predominant neuronal inclusion body 4-repeat tauopathy (LNT) correlating well with the signal alterations seen in MRI. DISCUSSION: Our observation broadens the spectrum of tau pathology associated with PC-PSP and suggests that memory deficit and hippocampal atrophy may be suggestive of non-Alzheimer's disease pathology, including LNT. Understanding the diverse range of tau morphologies may help explain phenotypic heterogeneity seen in PSP.

Influence of Health Education on Podiatric Knowledge, Self-care, and Conditions in Adults With Diabetes Mellitus: A Systematic Review.

OBJECTIVE: To determine if health education has an influence on podiatric knowledge, self-care, and conditions in adults with diabetes mellitus. DATA SOURCES: The authors conducted a literature search for Spanish-, English-, and Portuguese-language publications using PubMed, Scopus, Dialnet, and CUIDEN. STUDY SELECTION: Selected keywords related to diabetes, health education, (diabetic) foot, and self-care were searched, and the titles, abstracts, and relevant full-text articles were screened. Thirteen studies were selected with a total of 1,296 participants. Four were randomized controlled trials, and nine were quasi-experimental studies. DATA EXTRACTION: Data pertaining to preventive intervention and study outcomes were extracted. DATA SYNTHESIS: The preventive interventions used varied from traditional educational workshops and one-on-one patient education to new technological strategies. Three different outcomes were evaluated in each study: podiatric knowledge (n = 4), foot self-care (n = 13), and foot problems (n = 2). CONCLUSIONS: Health education interventions increase podiatric self-care in adults with diabetes mellitus. These interventions appear to contribute positively to foot health and podiatric knowledge.

Modelling herd immunity requirements in Queensland: impact of vaccination effectiveness, hesitancy and variants of SARS-CoV-2.

Long-term control of SARS-CoV-2 outbreaks depends on the widespread coverage of effective vaccines. In Australia, two-dose vaccination coverage of above 90% of the adult population was achieved. However, between August 2020 and August 2021, hesitancy fluctuated dramatically. This raised the question of whether settings with low naturally derived immunity, such as Queensland where less than [Formula: see text] of the population is known to have been infected in 2020, could have achieved herd immunity against 2021's variants of concern. To address this question, we used the agent-based model Covasim. We simulated outbreak scenarios (with the Alpha, Delta and Omicron variants) and assumed ongoing interventions (testing, tracing, isolation and quarantine). We modelled vaccination using two approaches with different levels of realism. Hesitancy was modelled using Australian survey data. We found that with a vaccine effectiveness against infection of 80%, it was possible to control outbreaks of Alpha, but not Delta or Omicron. With 90% effectiveness, Delta outbreaks may have been preventable, but not Omicron outbreaks. We also estimated that a decrease in hesitancy from 20% to 14% reduced the number of infections, hospitalizations and deaths by over 30%. Overall, we demonstrate that while herd immunity may not be attainable, modest reductions in hesitancy and increases in vaccine uptake may greatly improve health outcomes. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

Pattern of Recurrence of Glioblastoma Versus Grade 4 IDH-Mutant Astrocytoma Following Chemoradiation: A Retrospective Matched-Cohort Analysis.

Background and Purpose: To quantitatively compare the recurrence patterns of glioblastoma (isocitrate dehydrogenase-wild type) versus grade 4 isocitrate dehydrogenase-mutant astrocytoma (wild type isocitrate dehydrogenase and mutant isocitrate dehydrogenase, respectively) following primary chemoradiation. Materials and Methods: A retrospective matched cohort of 22 wild type isocitrate dehydrogenase and 22 mutant isocitrate dehydrogenase patients were matched by sex, extent of resection, and corpus callosum involvement. The recurrent gross tumor volume was compared to the original gross tumor volume and clinical target volume contours from radiotherapy planning. Failure patterns were quantified by the incidence and volume of the recurrent gross tumor volume outside the gross tumor volume and clinical target volume, and positional differences of the recurrent gross tumor volume centroid from the gross tumor volume and clinical target volume. Results: The gross tumor volume was smaller for wild type isocitrate dehydrogenase patients compared to the mutant isocitrate dehydrogenase cohort (mean ± SD: 46.5 ± 26.0 cm3 vs 72.2 ± 45.4 cm3, P = .026). The recurrent gross tumor volume was 10.7 ± 26.9 cm3 and 46.9 ± 55.0 cm3 smaller than the gross tumor volume for the same groups (P = .018). The recurrent gross tumor volume extended outside the gross tumor volume in 22 (100%) and 15 (68%) (P= .009) of wild type isocitrate dehydrogenase and mutant isocitrate dehydrogenase patients, respectively; however, the volume of recurrent gross tumor volume outside the gross tumor volume was not significantly different (12.4 ± 16.1 cm3 vs 8.4 ± 14.2 cm3, P = .443). The recurrent gross tumor volume centroid was within 5.7 mm of the closest gross tumor volume edge for 21 (95%) and 22 (100%) of wild type isocitrate dehydrogenase and mutant isocitrate dehydrogenase patients, respectively. Conclusion: The recurrent gross tumor volume extended beyond the gross tumor volume less often in mutant isocitrate dehydrogenase patients possibly implying a differential response to chemoradiotherapy and suggesting isocitrate dehydrogenase status might be used to personalize radiotherapy. The results require validation in prospective randomized trials.

Risk of sustained SARS-CoV-2 transmission in Queensland, Australia.

We used an agent-based model Covasim to assess the risk of sustained community transmission of SARSCoV-2/COVID-19 in Queensland (Australia) in the presence of high-transmission variants of the virus. The model was calibrated using the demographics, policies, and interventions implemented in the state. Then, using the calibrated model, we simulated possible epidemic trajectories that could eventuate due to leakage of infected cases with high-transmission variants, during a period without recorded cases of locally acquired infections, known in Australian settings as "zero community transmission". We also examined how the threat of new variants reduces given a range of vaccination levels. Specifically, the model calibration covered the first-wave period from early March 2020 to May 2020. Predicted epidemic trajectories were simulated from early February 2021 to late March 2021. Our simulations showed that one infected agent with the ancestral (A.2.2) variant has a 14% chance of crossing a threshold of sustained community transmission (SCT) (i.e., > 5 infections per day, more than 3 days in a row), assuming no change in the prevailing preventative and counteracting policies. However, one agent carrying the alpha (B.1.1.7) variant has a 43% chance of crossing the same threshold; a threefold increase with respect to the ancestral strain; while, one agent carrying the delta (B.1.617.2) variant has a 60% chance of the same threshold, a fourfold increase with respect to the ancestral strain. The delta variant is 50% more likely to trigger SCT than the alpha variant. Doubling the average number of daily tests from ∼ 6,000 to 12,000 results in a decrease of this SCT probability from 43 to 33% for the alpha variant. However, if the delta variant is circulating we would need an average of 100,000 daily tests to achieve a similar decrease in SCT risk. Further, achieving a full-vaccination coverage of 70% of the adult population, with a vaccine with 70% effectiveness against infection, would decrease the probability of SCT from a single seed of alpha from 43 to 20%, on par with the ancestral strain in a naive population. In contrast, for the same vaccine coverage and same effectiveness, the probability of SCT from a single seed of delta would decrease from 62 to 48%, a risk slightly above the alpha variant in a naive population. Our results demonstrate that the introduction of even a small number of people infected with high-transmission variants dramatically increases the probability of sustained community transmission in Queensland. Until very high vaccine coverage is achieved, a swift implementation of policies and interventions, together with high quarantine adherence rates, will be required to minimise the probability of sustained community transmission.