A Systematic Review of Cochlear Implant-Related Magnetic Resonance Imaging Artifact: Implications for Clinical Imaging.

OBJECTIVE: To conduct a systematic review of the existing literature with the aim of evaluating and consolidating the present understanding of strategies for mitigating magnetic resonance imaging (MRI) artifacts related to cochlear implants in adult and pediatric patients, covering both in-vivo and ex-vivo investigations. DATA SOURCES: A systematic review of MEDLINE-Ovid, Embase, Google Scholar, The Cochrane Library, and Scopus was performed from inception through April 2022. The protocol was registered with PROSPERO before commencement of data collection (CRD CRD42022319651). REVIEW METHODS: The data were screened and collected by two authors independently, and eligibility was assessed according to Cochrane Handbook and Preferred Reporting Items for Systematic Review and Meta-Analysis recommendations, whereas the quality of the articles was evaluated using the NIH Study Quality Assessment. RESULTS: The search yielded 2,354 potentially relevant articles, of which 27 studies were included in the final review. Twelve studies looked at 1.5-T MRI, four studies looked at 3-T MRI, eight studies looked at both 1.5 and 3 T, one study looked at 0.2 and 1.5 T, and one study looked at 3- and 7.0-T MRI. Nineteen studies focused on MRI sequences as a means of artifact reduction, nine studies focused on implant magnet positioning, two studies focused on head positioning, and one study focused on both magnet and head positioning. In terms of MRI sequences, diffusion-weighted imaging produced larger artifacts compared with other sequences, whereas fast spin echo/turbo spin echo sequences and fat suppression techniques produced smaller artifacts. The position of the magnet was also found to be important, with a magnet position more than 6.5 cm posterior to the external auditory canal producing the best images with the least distortion. The angle at which the magnet is placed also affects visibility of different brain structures. CONCLUSION: Proper head positioning, magnet placement at a distance of over 6.5 cm from the external auditory canal, use of spin echo sequences, and fat suppression techniques reduce the size and shape of MRI artifacts.

Single Institution Experience With International Referrals for Pediatric Cardiac Surgery.

BACKGROUND: Pediatric cardiac surgery in developing countries poses many challenges. The practice of referring patients from abroad via nongovernmental organizations has occurred for many years. We describe our experience with international referrals for pediatric cardiac surgery via Gift of Life Mid-South to the Heart Institute, Le Bonheur Children's Hospital in Memphis, Tennessee. METHODS: We performed a retrospective descriptive review of data collected in our Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD) along with data from our electronic medical record from January 1, 2007, to December 31, 2017. Available data included patient demographics, diagnoses, surgical procedure, entire inpatient length of stay (LOS), complications, and operative mortality. Cardiac surgeries were grouped according to the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery Mortality Categories (STAT Mortality Categories). Complications were defined according to the STS CHSD. RESULTS: In this retrospective descriptive study, case complexity level varied; however, 38% cardiac surgeries were in STAT Mortality Category 3 or 4. Honduras was the most common referral source with a total of 18 countries represented. Operative mortality remained very low (1 [1.4%] of 71 cardiac surgeries) despite patients being referred beyond infancy. There were an increasing number of complications and longer inpatient LOS (with greater variance) in STAT Mortality Category 4. CONCLUSIONS: International patients referred for congenital heart surgery can be successfully treated with an acceptable mortality rate despite late referrals. Inpatient LOS is related to surgical complexity. Follow-up studies are needed to determine the long-term outcomes of these patients.

Dexamethasone Use in the Treatment of Pediatric Deep Neck Space Infections.

OBJECTIVES: Assess the outcome of Intravenous (IV) dexamethasone in the treatment of pediatric deep neck space infections (DNSI) in combination with IV antibiotics. METHODS: Retrospective chart review of pediatric patients admitted for a DNSI from March 2014 to June 2016. Patient characteristics including demographics, abscess type, antibiotic, dexamethasone, surgery, culture, and length of stay (LOS) were obtained. Patients treated with antibiotics alone versus antibiotics and dexamethasone were compared. Primary outcome measures were rate of surgical drainage and LOS. RESULTS: Overall 153 patients with DNSI were identified, including 62 lateral neck, 18 parapharyngeal, 40 peritonsillar, 32 retropharyngeal, and 1 submandibular. All patients received antibiotics. Dexamethasone was used in 35% of patients. The rate of surgical drainage in the dexamethasone and non-dexamethasone group was 36% and 53% respectively (P = .043). LOS was shorter for the dexamethasone group (2.9 days) compared to the non-dexamethasone group (3.8 days) but was non-significant, P-value-.09. The most common microorganisms cultured were MRSA (25), MSSA (11), and Streptococcus pyogenes (10). CONCLUSION: Dexamethasone use was associated with a decreased rate of surgical drainage in pediatric patients with DNSI. Further prospective study is needed to determine the role of dexamethasone in treatment.

Effect of thyroid hormone on cardiac function following orthotopic heart transplantation in piglets.

Studies in adult HT have demonstrated improved cardiac function in the recipient following administration of T3 to the donor. The purpose of this experiment was to assess the effects of T3 on the function of the immature donor heart following HT in a piglet model. A total of 32 piglets were divided into 16 donors and 16 recipients. Following creation of brain death, half of the donor piglets were randomized to receive three doses of T3 (0.2 µg/kg) along with hydrocortisone (1 mg/kg). The donor hearts were then transplanted into the recipient piglets on CPB. Duration of survival off CPB, inotrope score, and EF of heart following CPB were evaluated. There were no differences between the two groups in age, weight, pre-brain death EF, T3 levels, and CPB times. Post-CPB survival times were inversely related to the ischemic times in both groups (Pearson r=-0.80, P<.001), and this relationship was not influenced by T3. There was no difference in inotrope score, EF, or biochemical assessment between the two groups. Administration of T3 in combination with hydrocortisone to the brain-dead donor confers no beneficial effect on myocardial function or survival following HT in a piglet model.

Bradford's law: identification of the core journals for neurosurgery and its subspecialties.

OBJECTIVE: Bradford's law describes the scatter of citations for a given subject or field. It can be used to identify the most highly cited journals for a field or subject. The objective of this study was to use currently accepted formulations of Bradford's law to identify core journals of neurosurgery and neurosurgical subspecialties. METHODS: All original research publications from 2009 to 2013 were analyzed for the top 25 North American academic neurosurgeons from each subspecialty. The top 25 were chosen from a ranked career h-index list identified from previous studies. Egghe's formulation and the verbal formulation of Bradford's law were applied to create specific citation density zones and identify the core journals for each subspecialty. The databases were then combined to identify the core journals for all of academic neurosurgery. RESULTS: Using Bradford's verbal law with 4 zone models, the authors were able to identify the core journals of neurosurgery and its subspecialties. The journals found in the most highly cited first zone are presented here as the core journals. For neurosurgery as a whole, the core included the following journals: Journal of Neurosurgery, Neurosurgery, Spine, Stroke, Neurology, American Journal of Neuroradiology, International Journal of Radiation Oncology Biology Physics, and New England Journal of Medicine. The core journals for each subspecialty are presented in the manuscript. CONCLUSIONS: Bradford's law can be used to identify the core journals of neurosurgery and its subspecialties. The core journals vary for each neurosurgical subspecialty, but Journal of Neurosurgery and Neurosurgery are among the core journals for each neurosurgical subspecialty.