Operational data for fault prognosis in particle accelerators with machine learning.

This paper presents real operational data collected from the power systems of the Spallation Neutron Source facility, which provides the most intense neutron beam in the world. The authors have used a radio-frequency test facility (RFTF) and simulated system failures in the lab without causing a catastrophic system failure. Waveform signals have been collected from the RFTF normal operation as well as during fault induction efforts. The dataset provides a significant amount of normal and faulty signals for the training of statistical or machine learning models. Then, the authors performed 21 test experiments, where the faults are slowly induced into the RFTF system for the purpose of testing the models in fault prognosis to detect and prevent impending faults. The test experiments include interesting combinations of magnetic flux compensation and start pulse width adjustments, which cause gradual deterioration in the waveforms (e.g., system output voltage, system output current, insulated-gate bipolar transistor currents, magnetic fluxes), which mimic the fault scenarios. Accordingly, this dataset can be valuable for developing models to predict impending fault scenarios in power systems in general and in particle accelerators in specific. All experiments occurred in the Spallation Neutron Source facility of Oak Ridge National Laboratory in Oak Ridge, Tennessee of the United States in July 2022.

Real electronic signal data from particle accelerator power systems for machine learning anomaly detection.

This article describes real time series datasets collected from the high voltage converter modulators (HVCM) of the Spallation Neutron Source facility. HVCMs are used to power the linear accelerator klystrons, which in turn produce the high-power radio frequency to accelerate the negative hydrogen ions (H-). Waveform signals have been collected from the operation of more than 15 HVCM systems categorized into four major subsystems during the years 2020-2022. The data collection process occurred in the Spallation Neutron Source facility of Oak Ridge, Tennessee in the United States. For each of the four subsystems, there are two datasets. The first one contains the waveform signals, while the second contains the label of the waveform, whether it has a normal or faulty signal. A variety of waveforms are included in the datasets including insulated-gate bipolar transistor (IGBT) currents in three phases, magnetic flux in the three phases, modulator current and voltage, cap bank current and voltage, and time derivative change of the modulator voltage. The datasets provided are useful to test and develop machine learning and statistical algorithms for applications related to anomaly detection, system fault detection and classification, and signal processing.

Efficacy of Autogenous Bone Marrow Aspirate as a Fusion-promoting Adjunct to Anterior Cervical Discectomy and Fusion: A Single Center Retrospective Cohort Study.

Background Autogenous iliac crest bone marrow aspirate (BMA) has been shown to be a safe osteobiological adjunct to anterior cervical discectomy and fusion (ACDF), but little evidence exists to support its superiority to traditional methods. The object of this study was to retrospectively evaluate two cohorts of patients undergoing ACDF - with or without the use of BMA - in an effort to better characterize the clinical and radiographic outcomes associated with the use of BMA in ACDF. Methods The charts of all patients undergoing ACDF with a collagen-hydroxyapatite (CHA) sponge, local vertebral autograft and a polyetheretherketone (PEEK) interbody graft with or without BMA by a single staff neurosurgeon between 2011 and 2016 were retrospectively reviewed. Post-operative dynamic plain films and CT scans for each patient were reviewed and each instrumented level was independently evaluated for fusion over time. Results A total of 203 cervical levels were instrumented in 92 patients (with BMA, 52 patients, 122 levels; without BMA, 40 patients, 81 levels). The mean radiographic follow-up period was 21.4 ± 18.4 months, over which time 154 of 203 (75.6%) instrumented cervical levels were found to have fused (BMA group, 93/122 segments fused [76.2%]; non-BMA group, 61/81 segments fused [75.3%], p = 1). Kaplan-Meier survival analysis demonstrated a higher probability of fusion at any given time point for the BMA group when compared with the non-BMA group (p < 0.001, log-rank test). Conclusions BMA is a readily accessible, low-cost adjunct to ACDF that enhances the fusion rates seen with a CHA/PEEK allograft combination.

Minimally Invasive, Stereotactic, Wireless, Percutaneous Pedicle Screw Placement in the Lumbar Spine: Accuracy Rates With 182 Consecutive Screws.

BACKGROUND: Standard fluoroscopic navigation and stereotactic computed tomography-guided lumbar pedicle screw instrumentation traditionally relied on the placement of Kirshner wires (K-wires) to ensure accurate screw placement. The use of K-wires, however, is associated with a risk of morbidity due to potential ventral displacement into the retroperitoneum. We report our experience using a computer image-guided, wireless method for pedicle screw placement. We hypothesize that minimally invasive, wireless pedicle screw placement is as accurate and safe as the traditional technique using K-wires while decreasing operative time and avoiding potential complications associated with K-wires. METHODS: We conducted a retrospective review of 42 consecutive patients who underwent a stereotactic-guided, wireless lumbar pedicle screw placement. All screws were placed to provide fixation to a variety of interbody fusion constructs including anterior lumbar interbody fusion, lateral interbody fusion, and transforaminal lumbar interbody fusion. The procedures were performed using the O-arm intraoperative imaging system with StealthStation navigation (Medtronic, Memphis, TN) and Medtronic navigated instrumentation. After placing a percutaneous navigation frame into the posterior superior iliac spine or onto an adjacent spinous process, an intraoperative O-arm image was obtained to allow subsequent StealthStation navigation. Para-median incisions were selected to allow precise percutaneous access to the target pedicles. The pedicles were cannulated using either a stereotactic drill or a novel awl-tipped tap along with a low-speed/high-torque power driver. The initial trajectory into the pedicle was recorded on the Medtronic StealthStation prior to removal of the drill or awl-tap, creating a "virtual" K-wire rather than inserting an actual K-wire to allow subsequent tapping and screw insertion. Accurate screw placement is achieved by following the virtual path as an exact computer-aided design model of the screw traversing the pedicle is projected onto the display and by using audible and tactile feedback. A second O-arm scan was obtained to confirm accuracy of screw placement. RESULTS: A total of 20 women and 22 men (average age = 56 years) underwent a total of 182 pedicle screw placements using the stereotactic, wireless technique. The total breach rate was 9.9%, with a clinically significant breach rate of 0% (defined as >2 mm medial breach or >4 mm lateral breach) and a clinical complication rate of 0%. CONCLUSIONS: Wireless, percutaneous placement of lumbar pedicle screws using computed tomography-guided stereotactic navigation is a safe, reproducible technique with very high accuracy rates.

Altered brain activation in military personnel with one or more traumatic brain injuries following blast.

Explosive blast is a frequent cause of traumatic brain injury (TBI) among personnel deployed to Afghanistan and Iraq. Functional magnetic resonance imaging (fMRI) with an event-related stimulus-response compatibility task was used to compare 15 subjects with mild, chronic blast-related TBI with 15 subjects who had not experienced a TBI or blast exposure during deployment. Six TBI subjects reported multiple injuries. Relative to the control group, TBI subjects had slightly slower responses during fMRI and increased somatic complaints and symptoms of post-traumatic stress disorder (PTSD) and depression. A between-group analysis indicated greater activation during stimulus-response incompatibility in TBI subjects within the anterior cingulate gyrus, medial frontal cortex, and posterior cerebral areas involved in visual and visual-spatial functions. This activation pattern was more extensive after statistically controlling for reaction time and symptoms of PTSD and depression. There was also a negative relationship between symptoms of PTSD and activation within posterior brain regions. These results provide evidence for increased task-related activation following mild, blast-related TBI and additional changes associated with emotional symptoms. Limitations of this study include no matching for combat exposure and different recruitment strategies so that the control group was largely a community-based sample, while many TBI subjects were seeking services.

Diffusion tensor imaging of mild to moderate blast-related traumatic brain injury and its sequelae.

To evaluate the effects of mild to moderate blast-related traumatic brain injury (TBI) on the microstructure of brain white matter (WM) and neurobehavioral outcomes, we studied 37 veterans and service members (mean age 31.5 years, SD = 7.2; post-injury interval 871.5 days; SD = 343.1), whose report of acute neurological status was consistent with sustaining mild to moderate TBI due to blast while serving in Iraq or Afghanistan. Fifteen veterans without a history of TBI or exposure to blast (mean age 31.4 years, SD = 5.4) served as a comparison group, including seven subjects with extracranial injury (post-injury interval 919.5 days, SD = 455.1), and eight who were uninjured. Magnetic resonance imaging disclosed focal lesions in five TBI participants. Post-concussion symptoms (Neurobehavioral Symptom Inventory), post-traumatic stress disorder (PTSD) symptoms (PTSD Checklist-Civilian), and global distress and depression (Brief Symptom Inventory) were worse in the TBI participants than the comparison group, but no group differences were found in perceived physical or mental functioning (SF-12). Verbal memory (Selective Reminding) was less efficient in the TBI group, but there were no group differences in nonverbal memory (Selective Reminding) or decision making (Iowa Gambling Task). Verbal memory in the TBI group was unrelated to PTSD severity. Diffusion tensor imaging (DTI) using tractography, standard single-slice region-of-interest measurement, and voxel-based analysis disclosed no group differences in fractional anisotropy (FA) and apparent diffusion coefficient (ADC). However, FA of the left and right posterior internal capsule and left corticospinal tract was positively correlated with total words consistently recalled, whereas ADC for the left and right uncinate fasciculi and left posterior internal capsule was negatively correlated with this measure of verbal memory. Correlations of DTI variables with symptom measures were non-significant and inconsistent. Our data do not show WM injury in mild to moderate blast-related TBI in veterans despite their residual symptoms and difficulty in verbal memory. Limitations of the study and implications for future research are also discussed.

A supratentorial, hemorrhagic, intraparenchymal epidermoid cyst.

Epidermoid cysts are slow growing benign tumors that represent < 1-2% of all intracranial tumors and rarely present as supratentorial, intraparenchymal masses. We present the first report of a supratentorial, hemorrhagic, intraparenchymal epidermoid cyst with its presentation, our operative approach, post-operative course, radiographic features, and a literature review.

Persistent trigeminal artery terminating in the posterior inferior cerebellar artery: case report.

OBJECTIVE: Persistent trigeminal arteries are rare and represent a remnant of the fetal carotid-basilar circulation. They typically extend from the internal carotid artery to the basilar artery. An unusual case of a patient with a trigeminal artery originating from the internal carotid artery and terminating as the dominant hemispheric branch of the posterior inferior cerebellar artery is presented. CLINICAL PRESENTATION: A 66-year-old woman presented to the emergency department with pulsatile tinnitus, increasing left eye pain, proptosis, conjunctival injection, diplopia, and decreased visual acuity. Conventional contrast-enhanced computed tomographic and magnetic resonance imaging demonstrated findings consistent with a left carotid-cavernous fistula. The patient underwent an emergency diagnostic cerebral angiogram. Besides an indirect carotid-cavernous fistula on the left side, a right-sided persistent trigeminal artery terminating as the dominant hemispheric trunk of the posteroinferior cerebellar artery was incidentally noted. The vermian branch of the right posteroinferior cerebellar artery arose from the ipsilateral vertebral artery, whereas duplicate superior cerebellar arteries supplied the left posteroinferior cerebellar artery region. INTERVENTION: The patient was treated for the indirect carotid-cavernous fistula with detachable platinum coils and N-butyl cyanoacrylate, resulting in the resolution of her symptoms. CONCLUSION: We report a case of a persistent trigeminal artery supplying only the cerebellar hemisphere. The clinical significance of this anomaly relates to its role in endovascular therapeutic and surgical complications and the paradoxical lesions in the cerebellum that occur as a result of carotid disease. We also discuss the Saltzman classification of persistent trigeminal arteries and their variants.

Unusual small choroid plexus cyst obstructing the foramen of monroe: case report.

This is a case report of unusual case of choroid plexus cyst at the right foramen of Monro in the anterior third ventricle that caused unilateral obstructive hydrocephalus. The value of small-FOV thin-section MR imaging in the diagnosis of small lesions of the foramen of Monroe is demonstrated. The immunohistochemical findings in choroid epithelial cysts in comparison with those of other types of cysts at this location are discussed.