The second cutaneous anthrax infection diagnosed by metagenomic next-generation sequencing: A case report.

RATIONALE: Anthrax is a severe zoonotic infectious disease caused by Bacillus anthracis. Most reported cases were traditionally diagnosed through culture and microscopy. We reported here the second case of cutaneous anthrax diagnosed by metagenomic next-generation sequencing (mNGS). PATIENT CONCERNS: A 63-year-old man had a history of contact with an unwell sheep, developing local redness and swelling on wrist. The dorsal side of the left hand and forearm, with tension blisters on the back of the left. DIAGNOSIS: B anthracis was detected from culturing and mNGS of tension blisters. INTERVENTIONS: On the second day of admission, the patient was administered 3.2 million units of penicillin every 6 hours, and isolated and closely observed. OUTCOMES: The patient improves and is discharged. LESSONS: Traditional bacterial cultures are time-consuming, while mNGS offers the advantage of accurate, quick, high-throughput, unbiased sequencing of all genetic material in a sample, which is a good technical tool for assisting in the diagnosis of rare pathogen infections.

Rare occurrence of pulmonary coinfection involving Aspergillus fumigatus and Nocardia cyriacigeorgica in immunocompetent patients based on NGS: A case report and literature review.

RATIONALE: In our search on PubMed, we found that reports of co-infections involving Aspergillus fumigatus and Nocardia cyriacigeorgica in the literature are notably scarce. Most cases have been documented in patients with compromised immune systems or underlying pulmonary conditions. In contrast, our patient did not present with any of these risk factors. Furthermore, there have been no recent incidents such as near-drowning or other accidents in the patient history. To the best of our knowledge, this case represents a hitherto unreported clinical scenario. To enhance comprehension, we conducted a comprehensive literature review by compiling a total of 20 case reports (spanning from 1984 to 2023) on co-infections involving Aspergillus and Nocardia species, retrieved from PubMed. PATIENT CONCERNS AND DIAGNOSIS: Chest CT revealed the presence of multiple nodules and clustered high-density shadows in both lungs. Bronchoscopy revealed mucosal congestion and edema in the apical segment of the right upper lobe of the lung, along with the presence of 2 spherical polypoid new organisms. The pathological analysis reported severe chronic inflammation with evidence of Aspergillus within the tissue. Next-Generation Sequencing of bronchoalveolar lavage fluid revealed the presence of reads corresponding to A fumigatus and N cyriacigeorgica. Positive cultures for A fumigatus and the Nocardia genus were yielded by prolonging the incubation of samples in the microbiology laboratory. INTERVENTIONS: Treatment with voriconazole for A fumigatus and sulfamethoxazole-trimethoprim for N cyriacigeorgica infection was given. OUTCOMES: The patient improved and was discharged. After 6 months of telephone follow-up, the patient reported no clinical symptoms, discontinued the medication on his own. LESSONS: A fumigatus and N cyriacigeorgica can manifest as a co-infection in immunocompetent patients. Clinicians should prioritize the significant advantages and value of NGS in detecting rare and mixed pathogens associated with pulmonary infections.

Exposure of Infants to Gradient Fields in a Baby MRI Scanner.

In pediatric magnetic resonance imaging (MRI), infants are exposed to rapid, time-varying gradient magnetic fields, leading to electric fields induced in the body of infants and potential safety risks (e.g. peripheral nerve stimulation). In this numerical study, the in situ electric fields in infants induced by small-sized gradient coils for a 1.5 T MRI scanner were evaluated. The gradient coil set was specially designed for the efficient imaging of infants within a small-bore (baby) scanner. The magnetic flux density and induced electric fields by the small x, y, z gradient coils in an infant model (8-week-old with a mass of 4.3 kg) were computed using the scalar potential finite differences method. The gradient coils were driven by a 1 kHz sinusoidal waveform and also a trapezoidal waveform with a 250 µs rise time. The model was placed at different scan positions, including the head area (position I), chest area (position II), and body center (position III). It was found that the induced electric fields in most tissues exceeded the basic restrictions of the ICNIRP 2010 guidelines for both waveforms. The electric fields were similar in the region of interest for all coil types and model positions but different outside the imaging region. The y-coil induced larger electric fields compared with the x- and z- coils. Bioelectromagnetics. 43:69-80, 2022. © 2021 Bioelectromagnetics Society.

A cone-shaped gradient coil design for high-resolution MRI head imaging.

Insertable head gradient coils offer significant advantages such as high gradient strength and fast gradient switching speed owing to shorter distances to the target region of interest than whole-body cylindrical coils. To produce superior gradient performance, the local head coil is typically designed with an asymmetric configuration to accommodate both the shoulders and head of a patient, leading to tough dimensional constraints and practical limits to the coil implementation. In this paper, we propose a new cone-shaped model to improve the performance of the asymmetric head coils and to mitigate patient claustrophobia. The primary coils are designed with a larger diameter at the patient end for access and a smaller diameter at the service end to bring wires closer to the human head, while the secondary coils are arranged on a cylindrical former to improve coil efficiency. Two cases are studied in this paper. Case I: inner bore size at the patient end (diameter 42 cm) is fixed as the design reference. In this case, inner diameters at any other position vary with the conical tilting angles. Compared with a set of conical gradient coils designed with tilting angles ranging from 0 to 14°, it is found that the optimal coil performance is achieved at the tilting angle of 14°. The key performance parameters have been improved by 100%-200% for the transverse coils, and about 50% for the longitudinal coils compared with the cylindrical counterpart with the reference bore size (that is, the same diameter of 42 cm). The conical coils also produce less heat in the gradient structure and lower acoustic noise in the field of view. Case II: inner bore size at the iso-centre (diameter 34 cm) is set as the design reference. It is also found that, compared with 34 cm diameter cylindrical coils, the conical transverse coil performance has been improved at an angle of 14°. The key coil performance increases by 20%-50% for transverse coil but decreases by 20%-40% for the longitudinal coil. However, compared with the tight cylindrical structure (e.g. 34 cm diameter), the tilting angle will provide patient-friendly space for imaging and handling, which can be critical for fMRI and other brain studies.