Subsecond accurate myelin water fraction reconstruction from FAST-T2 data with 3D UNET.

PURPOSE: To develop a 3D UNET convolutional neural network for rapid extraction of myelin water fraction (MWF) maps from six-echo fast acquisition with spiral trajectory and T2 -prep data and to evaluate its accuracy in comparison with multilayer perceptron (MLP) network. METHODS: The MWF maps were extracted from 138 patients with multiple sclerosis using an iterative three-pool nonlinear least-squares algorithm (NLLS) without and with spatial regularization (srNLLS), which were used as ground-truth labels to train, validate, and test UNET and MLP networks as a means to accelerate data fitting. Network testing was performed in 63 patients with multiple sclerosis and a numerically simulated brain phantom at SNR of 200, 100 and 50. RESULTS: Simulations showed that UNET reduced the MWF mean absolute error by 30.1% to 56.4% and 16.8% to 53.6% over the whole brain and by 41.2% to 54.4% and 21.4% to 49.4% over the lesions for predicting srNLLS and NLLS MWF, respectively, compared to MLP, with better performance at lower SNRs. UNET also outperformed MLP for predicting srNLLS MWF in the in vivo multiple-sclerosis brain data, reducing mean absolute error over the whole brain by 61.9% and over the lesions by 67.5%. However, MLP yielded 41.1% and 51.7% lower mean absolute error for predicting in vivo NLLS MWF over the whole brain and the lesions, respectively, compared with UNET. The whole-brain MWF processing time using a GPU was 0.64 seconds for UNET and 0.74 seconds for MLP. CONCLUSION: Subsecond whole-brain MWF extraction from fast acquisition with spiral trajectory and T2 -prep data using UNET is feasible and provides better accuracy than MLP for predicting MWF output of srNLLS algorithm.

Use of 70- to 150-µm Radiopaque Spherical Embolics for Prostatic Artery Embolization.

This retrospective report describes treatment of 21 patients who underwent prostatic artery embolization using 70- to 150-µm radiopaque microspheres for lower urinary tract symptoms secondary to benign prostatic hyperplasia. Seventeen patients (81%) received successful bilateral prostatic artery embolization. At a mean follow-up of 42 days (range, 25-59 days), patients showed improvement in International Prostate Symptom Score (n = 11; mean = 10.6; P = .001), quality of life score (n = 17; mean = 2.0; P = .02), and International Index of Erectile Function (n = 17; mean = 9.3; P = .01). The mean prostate volume reduction was 28 mL (16.2%; P = .003). Nontarget embolization occurred twice, resulting in 1 minor adverse event of hematospermia.

Effect of Median Lobe Enlargement on Early Prostatic Artery Embolization Outcomes.

PURPOSE: To evaluate outcomes after prostatic artery embolization (PAE) in patients with severe intravesical prostatic protrusion (IPP). MATERIALS AND METHODS: This was a retrospective, single health system, 2-hospital study from April 2015 to December 2018 of 54 patients who underwent elective PAE procedures (age mean 67.5 years; standard deviation [SD] 8.5). The cohort had a mean ellipsoid prostate volume of 100.1 cm3 (SD 56.7), a mean baseline International Prostate Symptom Score (IPSS) of 18.7 (SD 8.2), a mean baseline quality of life (QOL) score of 4.1 (SD 1.4), and a median follow-up of 38 days (range 10-656 days). Outcomes including IPSS and QOL score reduction (where a lower QOL score indicates an improvement in QOL), and clinical success were compared between severe (≥10 mm) and nonsevere (<10 mm) IPP patients. A linear regression model was used to examine the impact of IPP on these outcomes. RESULTS: No significant differences in patient characteristics were found between nonsevere (n = 17) and severe (n = 37) IPP patients. Both cohorts showed IPSS reduction (nonsevere 6.0, P = .0397; severe 8.2, P < .0001) and QOL score reduction (nonsevere 1.0, P = .102; severe 2.0, P < .0001). No significant differences in IPSS or QOL score reduction were found between the cohorts (P = .431 and P = .127). Linear regression found that baseline IPP was not a significant contributor to the outcomes (IPSS: R2 = .5, P < .0001; IPP: P = .702; QOL: R2 = .5, P = .0003; IPP: P = .108). CONCLUSIONS: There were no significant differences in early outcomes in PAE between patients with severe and nonsevere IPP.

SozRank: A new approach for localizing the epileptic seizure onset zone.

Epilepsy is one of the most common neurological disorders affecting about 1% of the world population. For patients with focal seizures that cannot be treated with antiepileptic drugs, the common treatment is a surgical procedure for removal of the seizure onset zone (SOZ). In this work we introduce an algorithm for automatic localization of the seizure onset zone (SOZ) in epileptic patients based on electrocorticography (ECoG) recordings. The proposed algorithm builds upon the hypothesis that the abnormal excessive (or synchronous) neuronal activity in the brain leading to seizures starts in the SOZ and then spreads to other areas in the brain. Thus, when this abnormal activity starts, signals recorded at electrodes close to the SOZ should have a relatively large causal influence on the rest of the recorded signals. The SOZ localization is executed in two steps. First, the algorithm represents the set of electrodes using a directed graph in which nodes correspond to recording electrodes and the edges' weights quantify the pair-wise causal influence between the recorded signals. Then, the algorithm infers the SOZ from the estimated graph using a variant of the PageRank algorithm followed by a novel post-processing phase. Inference results for 19 patients show a close match between the SOZ inferred by the proposed approach and the SOZ estimated by expert neurologists (success rate of 17 out of 19).

Comparative Analysis of Cone-Beam CT Angiogram and Conventional CT Angiogram for Prostatic Artery Identification Prior to Embolization.

Pre-prostatic artery embolization (PAE) cone-beam computed tomography (CT) angiograms (n = 31; mean age: 62.4 ± 9.75 years) and conventional CT angiograms (n = 32; mean age: 62.5 ± 7.2 years) were retrospectively compared. Mean signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), radiation exposure, and prostatic artery (PA) identification scores (0-4) for cone-beam CT angiogram and conventional CT angiogram were 33.19 (± 14.31) and 18.13 (± 5.38) (P < .01); 27.42 (± 13.39) and 14.78 (± 4.92) (P < .01); 14.57 mSv (±2.5) and 19.25 mSv (±3.7) (P < .01); 3.36 (± 0.89) and 3.16 (± 0.95) (P = .08), respectively. Pre-PAE cone-beam CT angiogram allows for PA identification with improved SNR and CNR and less radiation dose compared to conventional CT angiogram.

Incidence and Clinical Significance of Renal Infarct After Fenestrated Endovascular Aortic Aneurysm Repair.

OBJECTIVE: The purpose of this study is to determine the incidence and clinical significance of renal infarcts after fenestrated endovascular aortic aneurysm repair (FEVAR). MATERIALS AND METHODS: All patients who underwent FEVAR with unenhanced and contrast-enhanced CT angiography during a 4-year period were retrospectively reviewed. Two staff radiologists reviewed pre- and post-FEVAR CT examinations for the presence of renal infarcts. Pre- and postoperative serum creatinine levels were examined to determine statistical significance. The incidence of renal infarct and percentage of renal volume reduction were calculated. RESULTS: Ninety patients were included for analysis. All patients had a mild progressive increase in serum creatinine level after FEVAR. Twenty-three patients (26%) had a renal infarct identified on post-FEVAR CT, nine (39%) of which were secondary to intentional exclusion of an accessory renal artery and 14 (61%) of which were presumed to be embolic. Two patients with presumed embolic infarcts and three with exclusion of an accessory renal artery had an increase in serum creatinine level of greater than 0.3 mg/dL at 1 month after FEVAR. CONCLUSION: Although renal infarcts are common after FEVAR, the clinical relevance of these events appears to be limited, with less than one-quarter of patients with renal infarcts experiencing a decline in renal function.

Autocrine A2 in the T-system of ventricular myocytes creates transmural gradients in ion transport: a mechanism to match contraction with load?

Transmural heterogeneities in Na/K pump current (IP), transient outward K(+)-current (Ito), and Ca(2+)-current (ICaL) play an important role in regulating electrical and contractile activities in the ventricular myocardium. Prior studies indicated angiotensin II (A2) may determine the transmural gradient in Ito, but the effects of A2 on IP and ICaL were unknown. In this study, myocytes were isolated from five muscle layers between epicardium and endocardium. We found a monotonic gradient in both Ip and Ito, with the lowest currents in ENDO. When AT1Rs were inhibited, EPI currents were unaffected, but ENDO currents increased, suggesting endogenous extracellular A2 inhibits both currents in ENDO. IP- and Ito-inhibition by A2 yielded essentially the same K0.5 values, so they may both be regulated by the same mechanism. A2/AT1R-mediated inhibition of IP or Ito or stimulation of ICaL persisted for hours in isolated myocytes, suggesting continuous autocrine secretion of A2 into a restricted diffusion compartment, like the T-system. Detubulation brought EPI IP to its low ENDO value and eliminated A2 sensitivity, so the T-system lumen may indeed be the restricted diffusion compartment. These studies showed that 33-50% of IP, 57-65% of Ito, and a significant fraction of ICaL reside in T-tubule membranes where they are transmurally regulated by autocrine secretion of A2 into the T-system lumen and activation of AT1Rs. Increased AT1R activation regulates each of these currents in a direction expected to increase contractility. Endogenous A2 activation of AT1Rs increases monotonically from EPI to ENDO in a manner similar to reported increases in passive tension when the ventricular chamber fills with blood. We therefore hypothesize load is the signal that regulates A2-activation of AT1Rs, which create a contractile gradient that matches the gradient in load.

Endobronchial Phenylephrine in Airway Bleeding During Bronchoscopy Does not Cause Hypertension: A Retrospective Observational Study.

BACKGROUND: Bleeding is a known complication during bronchoscopy, with increased incidence in patients undergoing a more invasive procedure. Phenylephrine is a potent vasoconstrictor that can control airway bleeding when applied topically and has been used as an alternative to epinephrine. The clinical effects of endobronchial phenylephrine on systemic vasoconstriction have not been clearly evaluated. Here, we compared the effects of endobronchial phenylephrine versus cold saline on systemic blood pressure. METHODS: In all, 160 patients who underwent bronchoscopy and received either endobronchial phenylephrine or cold saline from July 1, 2017 to June 30, 2022 were included in this retrospective observational study. Intra-procedural blood pressure absolute and percent changes were measured and compared between the 2 groups. RESULTS: There were no observed statistical differences in blood pressure changes between groups. The median absolute change between the median and the maximum intra-procedural systolic blood pressure in the cold saline group was 29 mm Hg (IQR 19 to 41) compared with 31.8 mm Hg (IQR 18 to 45.5) in the phenylephrine group. The corresponding median percent changes in SBP were 33.6 % (IQR 18.8 to 39.4) and 28% (IQR 16.8 to 43.5) for the cold saline and phenylephrine groups, respectively. Similarly, there were no statistically significant differences in diastolic and mean arterial blood pressure changes between both groups. CONCLUSIONS: We found no significant differences in median intra-procedural systemic blood pressure changes comparing patients who received endobronchial cold saline to those receiving phenylephrine. Overall, this argues for the vascular and systemic safety of phenylephrine for airway bleeding as a reasonable alternative to epinephrine.

Age and facial nerve axotomy-induced T cell trafficking: relation to microglial and motor neuron status.

Following peripheral axotomy of the facial nerve in mice, T lymphocytes cross the blood-brain-barrier (BBB) into the central nervous system (CNS), where they home to the neuronal cell bodies of origin in the facial motor nucleus (FMN) and act in concert with microglial cells to support the injured motor neurons. Several lines of evidence suggested normal aging may alter the injury-related responses of T cells, microglia, and motor neurons in this model. In this study, we therefore sought to test the hypothesis that compared to 8-week-old mice (young adult), 52-week-old mice (advanced middle age) would exhibit more neuronal damage and increased T cell trafficking into the injured FMN following facial nerve resection. Comparison of 8- and 52-week-old mice at 7, 14, 21, and 28 days post-resection of the facial nerve, confirmed our hypothesis that age influences the kinetics of CD3(+) T lymphocyte trafficking in the axotomized FMN. The peak T cell response was significantly higher, occurred later, and remained elevated longer in the injured FMN of mice in the 52 week age group. Although the kinetics of motor neuron death (identified by quantifying CD11b(+) perineuronal microglial phagocytic clusters engulfing the dead neurons at 7, 14, 21, and 28 days post-resection) differed between the age groups, motor neuron profile counts at day 28 showed that levels of cumulative motor neuron loss did not differ between the age groups. Compared to 8-week-old mice, however, there was small reduction in the mean cell size of the surviving motor neurons in the 52 week age group. Since T lymphocyte function decreases with normal aging, it will be important to determine if increased T cell trafficking into the injured CNS is a compensatory response to the decreased function of older T cells, and if these and related neuroimmunological changes are more pronounced in mice in the late stages of the life cycle.

The effect of emergency department crowding on lung-protective ventilation utilization for critically ill patients.

OBJECTIVE: To measure effects of ED crowding on lung-protective ventilation (LPV) utilization in critically ill ED patients. METHODS: This is a retrospective cohort study of adult mechanically ventilated ED patients admitted to the medical intensive care unit (MICU), over a 3.5-year period at a single academic tertiary care hospital. Clinical data, including reason for intubation, severity of illness (MPM0-III), acute respiratory distress syndrome (ARDS) risk score (EDLIPS), and ventilator settings were extracted via electronic query of electronic health record and standardized chart abstraction. Crowding metrics were obtained at 5-min intervals and averaged over the ED stay, stratified by acuity and disposition. Multivariate logistic regression was used to predict likelihood of LPV prior to ED departure. RESULTS: Mechanical ventilation was used in 446 patients for a median ED duration of 3.7 h (interquartile ratio, IQR, 2.3, 5.6). Mean MPM0-III score was 32.5 ±â€¯22.7, with high risk for ARDS (EDLIPS ≥5) seen in 373 (82%) patients. Initial and final ED ventilator settings differed in 134 (30.0%) patients, of which only 47 (35.1%) involved tidal volume changes. Higher percentages of active ED patients (workup in-progress) and those requiring eventual admission were associated with lower odds of LPV utilization by ED departure (OR 0.97, 95%CI 0.94-1.00; OR 0.97, 95%CI 0.94-1.00, respectively). In periods of high volume, ventilator adjustments to settings other than the tidal volume were associated with higher odds of LPV utilization. Reason for intubation, MPM0-III, and EDLIPS were not associated with LPV utilization, with no interactions detected in times of crowding. CONCLUSIONS: ED patients remain on suboptimal tidal volume settings with infrequent ventilator adjustments during the ED stay. Hospitals should focus on both systemic factors and bedside physician and/or respiratory therapist interventions to increase LPV utilization in times of ED boarding and crowding for all patients.

Identifying emergency department patients with chest pain who are at low risk for acute coronary syndromes [digest].

Though a minority of patients presenting to the emergency department with chest pain have acute coronary syndromes,identifying the patients who may be safely discharged and determining whether further testing is needed remains challenging. From the prehospital care setting to disposition and follow-up, this systematic review addresses the fundamentals of the emergency department evaluation of patients determined to be at low risk for acute coronary syndromes or adverse outcomes. Clinical risk scores are discussed, as well as the evidence and indications for confirmatory testing. The emerging role of new technologies, such as high-sensitivity troponin assays and advanced imaging techniques, are also presented. [Points & Pearls is a digest of Emergency Medicine Practice].

Emergency department management of priapism [digest].

Priapism is a genitourinary emergency that demands a thorough, time-sensitive evaluation. There are 3 types of priapism: ischemic, nonischemic, and recurrent ischemic priapism; ischemic priapism accounts for 95% of cases. Ischemic priapism must be treated within 4 to 6 hours to minimize morbidity, including impotence. The diagnosis of ischemic priapism relies heavily on the history and physical examination and may be facilitated by penile blood gas analysis and penile ultrasound. This issue reviews current evidence regarding emergency department treatment of ischemic priapism using a stepwise approach that begins with aspiration of cavernosal blood, cold saline irrigation, and penile injection with sympathomimetic agents. Evidence-based management and appropriate urologic follow-up of nonischemic and recurrent ischemic priapism maximizes patient outcomes and resource utilization. [Points & Pearls is a digest of Emergency Medicine Practice].

Sedative-hypnotic drug withdrawal syndrome: recognition and treatment [digest].

Sedative-hypnotic drugs include gamma-Aminobutyric acid (GABA)ergic agents such as benzodiazepines, barbiturates, gamma-Hydroxybutyric acid [GHB], gamma-Butyrolactone [GBL], baclofen, and ethanol. Chronic use of these substances can cause tolerance, and abrupt cessation or a reduction in the quantity of the drug can precipitate a life-threatening withdrawal syndrome. Benzodiazepines, phenobarbital, propofol, and other GABA agonists or analogues can effectively control symptoms of withdrawal from GABAergic agents. Managing withdrawal symptoms requires a patient-specific approach that takes into account the physiologic pathways of the particular drugs used as well as the patient's age and comorbidities. Adjunctive therapies include alpha agonists, beta blockers, anticonvulsants, and antipsychotics. Newer pharmacological therapies offer promise in managing withdrawal symptoms. [Points & Pearls is a digest of Emergency Medicine Practice].