Understanding Bias in Artificial Intelligence: A Practice Perspective.

In the fall of 2021, several experts in this space delivered a Webinar hosted by the American Society of Neuroradiology (ASNR) Diversity and Inclusion Committee, focused on expanding the understanding of bias in artificial intelligence, with a health equity lens, and provided key concepts for neuroradiologists to approach the evaluation of these tools. In this perspective, we distill key parts of this discussion, including understanding why this topic is important to neuroradiologists and lending insight on how neuroradiologists can develop a framework to assess health equity-related bias in artificial intelligence tools. In addition, we provide examples of clinical workflow implementation of these tools so that we can begin to see how artificial intelligence tools will impact discourse on equitable radiologic care. As continuous learners, we must be engaged in new and rapidly evolving technologies that emerge in our field. The Diversity and Inclusion Committee of the ASNR has addressed this subject matter through its programming content revolving around health equity in neuroradiologic advances.

The Use of Virtual Reality in Teaching Three-Dimensional Anatomy and Pathology on CT.

While radiological imaging is presented as two-dimensional images either on radiography or cross-sectional imaging, it is important for interpreters to understand three-dimensional anatomy and pathology. We hypothesized that virtual reality (VR) may serve as an engaging and effective way for trainees to learn to extrapolate from two-dimensional images to an understanding of these three-dimensional structures. We created a Google Cardboard Virtual Reality application that depicts intracranial vasculature and aneurysms. We then recruited 12 medical students to voluntarily participate in our study. The performance of the students in identifying intracranial aneurysms before and after the virtual reality training was evaluated and compared to a control group. While the experimental group's performance in correctly identifying aneurysms after virtual reality educational intervention was better than the control's (experimental increased by 5.3%, control decreased by 2.1%), the difference was not statistically significant (p-value of 0.06). Significantly, survey data from the medical students was very positive with students noting they preferred the immersive virtual reality training over conventional education and believed that VR would be a helpful educational tool for them in the future. We believe virtual reality can serve as an important tool to help radiology trainees better understand three-dimensional anatomy and pathology.

Acute Unilateral Proptosis After Blunt Orbital Trauma in an Adolescent Patient.

A male patient aged 16 years with a recent history of blunt trauma to the periorbita presented with blurred vision, pain, and proptosis of the right eye. MRI imaging revealed an intraconal mass. What would you do next?

Multiple Cranial Neuropathies and Pachymeningitis in a Patient With a Pathogenic Nucleotide-Binding Oligomerization Domain 2 Polymorphism.

ABSTRACT: An 11-year-old boy presented with 2 weeks of intermittent headache, right orbital pain, and constant diplopia. Brain MRI showed dural thickening and enhancement of the right lateral cavernous sinus, right orbital apex, and tentorium. Initial cerebral spinal fluid analysis showed only mild pleocytosis, and serum diagnostics were unrevealing. The working diagnosis was Tolosa-Hunt syndrome. His pain and sixth nerve palsy resolved with corticosteroids. Five months after initial presentation, he developed new numbness of the right cheek, complete right ophthalmoplegia, and weakness and numbness of his right hand and leg, all of which were responsive to steroids. Fifteen months later, he returned to the emergency department with 2 weeks of left-sided headaches and acute diplopia. On examination, he had a left cranial nerve 6 palsy. Dural biopsy showed diffuse mononuclear inflammatory cell reaction consisting mostly of lymphocytes with no signs of granuloma formation, nor any epithelioid or giant cells. His clinical course was consistent with an autoinflammatory condition of unknown etiology. Genetic testing with an immunodeficiency panel showed a risk allele in NOD2 (nucleotide-binding oligomerization domain 2) c.3019dup (p.Leu1007Prof*2) that is associated with an increased risk for Crohn disease. His clinical condition had similarities to central nervous system sarcoidosis. Because of the similarities between our patient's clinical, imaging, and genetic findings and neurosarcoidosis, he was switched to a more targeted therapy-infliximab. His condition has since been stable for nearly 2 years. In conclusion, genetic testing should be considered in patients with suspected occult autoimmunity.

Effects of hydrological and climatic variables on cyanobacterial blooms in four large shallow lakes fed by the Yangtze River.

Shallow lakes, one of the most widespread water bodies in the world, are easily shifted to a new trophic state due to external interferences. Shifting hydrologic conditions and climate change can cause cyanobacterial harmful algal blooms (CyanoHABs) in shallow lakes, which pose serious threats to ecological integrity and human health. This study analyzed the effects of hydrologic and meteorological variables on cyanobacterial blooms in Yangtze-connected lakes (Lake Dongting and Poyang) and isolated lakes (Lake Chao and Tai). The results show that (i) chlorophyll-a (Chl-a) concentration tends to decrease exponentially with increasing relative lake level fluctuations (RLLF) and precipitation, but to increase linearly with increasing wind speed and air temperature; (ii) Chl-a concentrations in lakes were significantly higher when RLLF < 100, precipitation < 2.6 mm, wind speed > 2.6 m s-1, or air temperature > 17.8 °C; (iii) the Chl-a concentration of Yangtze-isolated lakes was more significantly affected by water level amplitude, precipitation, wind speed and air temperature than the Yangtze-connected lakes; (iv) the RLLF and the ratio of wind speed to mean water depth could be innovative coupling factors to examine variation characteristics of Chl-a in shallow lakes with greater correlation than single factors.

Magnetic Resonance Imaging and Clinical Factors Associated With Ischemic Stroke in Patients Suspected of Cervical Artery Dissection.

Background and Purpose- Cervical artery dissection is a major cause of ischemic stroke in the young and presents with various imaging findings, including stenosis and intramural hematoma (IMH). Our goal was to determine the relative contribution of lumen findings and IMH to acute ischemic stroke and whether a heavily T1-weighted sequence could more reliably detect IMH. Methods- Institutional review board approval was obtained for this retrospective study of 254 patients undergoing magnetic resonance imaging/magnetic resonance angiography for suspected dissection. Imaging included standard turbo spin-echo (TSE) T1-fat saturation and heavily T1-weighted flow-suppressed magnetization-prepared rapid acquisition gradient-recalled echo sequences. Subjects with stents (1) or atherosclerotic disease (26) were excluded, leaving 227 subjects. Kappa analysis was used to determine IMH interrater reliability on magnetization-prepared rapid acquisition gradient-recalled echo and T1-fat saturation in 4 vessels per subject. Lumen findings, cardiovascular risk factors, medications, and nondissection stroke sources were recorded. Mixed-effects multivariate Poisson regression was used to determine the prevalence ratio of each factor with acute ischemic stroke, accounting for 4 vessels per patient with backward elimination to a threshold P value of 0.10. Results- Patients were 41.9% men, mean age of 47.3±16.6 years, with 114 dissections and 107 strokes. IMH interrater reliability was significantly higher for magnetization-prepared rapid acquisition gradient-recalled echo (κ=0.83; 95% CI, 0.78-0.86) versus T1-fat saturation (0.58; 95% CI, 0.57-0.68). The final acute stroke prediction model included magnetization-prepared rapid acquisition gradient-recalled echo-detected IMH (prevalence ratio, 2.0; 95% CI, 1.1-3.9; P=0.034), stenosis, pseudoaneurysm, male sex, current smoking, and nondissection stroke sources. The final model had high discrimination for acute stroke (area under the curve, 0.902; 95% CI, 0.872-0.932), compared with models without stenosis (0.861; 95% CI, 0.821-0.902), and without stenosis and IMH (0.831; 95% CI, 0.783-0.879). All 3 models were significantly different at P<0.05. Conclusions- Along with stenosis, IMH detection significantly contributed to acute ischemic stroke pathogenesis in patients with suspected cervical artery dissection. In addition, IMH detection can be made more reliable with heavily T1-weighted sequences.

Stroke Due to Cerebral Vasculitis in a Patient with Relentless Placoid Chorioretinitis.

PURPOSE: To report the first case of stroke in a patient with relentless placoid chorioretinitis. METHODS: Observational case report. RESULTS: A 20-year-old female with newly diagnosed relentless placoid chorioretinitis was urgently evaluated for unilateral paresthesias. She was found to have acute bilateral pontine strokes and cerebral vasculitis on magnetic resonance imaging of the brain and cerebral angiography. CONCLUSIONS: We report the first case of stroke due to cerebral vasculitis in a patient with relentless placoid chorioretinitis. This case emphasizes the need for timely evaluation of neurological symptoms in patients with this ocular diagnosis.

GoPro Hero Cameras for Creation of a Three-Dimensional, Educational, Neurointerventional Video.

Neurointerventional education relies on an apprenticeship model, with the trainee observing and participating in procedures with the guidance of a mentor. While educational videos are becoming prevalent in surgical cases, there is a dearth of comparable educational material for trainees in neurointerventional programs. We sought to create a high-quality, three-dimensional video of a routine diagnostic cerebral angiogram for use as an educational tool. A diagnostic cerebral angiogram was recorded using two GoPro HERO 3+ cameras with the Dual HERO System to capture the proceduralist's hands during the case. This video was edited with recordings from the video monitors to create a real-time three-dimensional video of both the actions of the neurointerventionalist and the resulting wire/catheter movements. The final edited video, in either two or three dimensions, can serve as another instructional tool for the training of residents and/or fellows. Additional videos can be created in a similar fashion of more complicated neurointerventional cases. The GoPro HERO 3+ camera and Dual HERO System can be used to create educational videos of neurointerventional procedures.

Educational Material for 3D Visualization of Spine Procedures: Methods for Creation and Dissemination.

Spine anatomy can be difficult to master and is essential for performing spine procedures. We sought to utilize the rapidly expanding field of 3D technology to create freely available, interactive educational materials for spine procedures. Our secondary goal was to convey lessons learned about 3D modeling and printing. This project involved two parallel processes: the creation of 3D-printed physical models and interactive digital models. We segmented illustrative CT studies of the lumbar and cervical spine to create 3D models and then printed them using a consumer 3D printer and a professional 3D printing service. We also included downloadable versions of the models in an interactive eBook and platform-independent web viewer. We then provided these educational materials to residents with a pretest and posttest to assess efficacy. The "Spine Procedures in 3D" eBook has been downloaded 71 times as of October 5, 2016. All models used in the book are available for download and printing. Regarding test results, the mean exam score improved from 70 to 86%, with the most dramatic improvement seen in the least experienced trainees. Participants reported increased confidence in performing lumbar punctures after exposure to the material. We demonstrate the value of 3D models, both digital and printed, in learning spine procedures. Moreover, 3D printing and modeling is a rapidly expanding field with a large potential role for radiologists. We have detailed our process for creating and sharing 3D educational materials in the hopes of motivating and enabling similar projects.

Simbu Ptosis: An Outreach Approach to Myogenic Ptosis in Eastern Highlands of Papua New Guinea-Experience and Results From a High-Volume Oculoplastic Surgical Camp.

PURPOSE: To present the results of a high-volume oculoplastic surgical outreach in a remote region of Simbu Province in the Eastern Highlands of Papua New Guinea. The authors describe the clinical features and evaluation and treatment of a novel ptosis syndrome found in this area. DESIGN: A team of 4 international ophthalmologists and 3 local doctors and 3 local nurses involved in a high-volume field intervention for all patients presenting with a bilateral ptosis to Mingende Rural Hospital. METHODS: Patients were systematically evaluated and treated during a 6-day surgical outreach and followed daily for 1 week and as needed via telemedicine. Visiting surgeons provided skills-transfer instruction for 3 local doctors and 3 nurses. Data collected included demographic information, history of present illness, past medical history, family history, social history, and a complete ophthalmologic and targeted neurologic evaluation. Patients were offered surgical intervention if they met criteria for safe eyelid elevation and could present for follow ups. Detailed notes of patient geographic location, history, and risk factors were collected in addition to pre- and postoperative photos. MAIN OUTCOME MEASURES: Efficient triage and treatment of all patients referred to the remote oculoplastic clinic. RESULTS: A total of 97 patients presented to the camp; of these, 87 underwent complete evaluation. There were 72 patients with ptosis, of which 60 were found to be of Simbu-type. These patients were grouped clinically by degree of ptosis: mild, moderate, and severe. Thirty-eight patients had moderate ptosis of which 34 underwent surgical intervention. Eleven patients with mild ptosis were counseled and observed. The 10 patients with severe ptosis and 2 with moderate ptosis were treated medically with ptosis crutches manufactured on site. A new technique for creating ptosis crutch glasses was developed. CONCLUSIONS: A new variant of progressive myogenic ptosis was identified. A high-volume oculoplastic surgical camp is an efficient way to systematically evaluate and treat this new entity. Skills-transfer training for local doctors and staff ensured continuity of care for the surgical patients.

Bedside Treatment of Chronic Subdural Hematoma: Using Radiographic Characteristics to Revisit the Twist Drill.

BACKGROUND AND STUDY AIMS: Conventional treatment strategies for the management of symptomatic chronic subdural hematoma (cSDH) in the elderly include observation, operative burr holes or craniotomy, and bedside twist drill drainage. The decision on which technique to use should be determined by weighing the comorbidities and symptoms of the patient with the potential risks and benefits. The goal of this study was to identify radiographic characteristics on computed tomography scan that might be used to guide surgical decision making in terms of operative versus bedside removal of cSDH. METHODS: We retrospectively reviewed clinical and radiographic features in patients who underwent bedside twist drill evacuation of a cSDH and those for a cohort of patients who underwent operative intervention via burr holes. RESULTS: We did not identify any clinical features or preoperative imaging characteristics to suggest an advantage of one procedure over the other. Additionally, complete radiographic resolution of cSDH on postoperative imaging is not required to relieve patient symptoms. CONCLUSION: Although bedside twist drill evacuation may avoid operating room costs and anesthetic complications in an elderly patient population and allow earlier resumption of anticoagulation treatment if necessary, there is also a risk of morbidity if uncontrolled bleeding is encountered or the patient is unable to tolerate the bedside procedure. However, bedside twist drill craniostomy is a reasonable and effective option for the treatment of subacute/chronic SDH in patients who may not be optimal surgical candidates.

Pigmented villonodular synovitis of the cervical spine: case report and review of the literature.

Pigmented villonodular synovitis (PVNS) is an uncommon, benign, but locally aggressive lesion characterized most commonly by synovial proliferation of the appendicular large joints, but occasionally involving a bursa or the tendon sheath. PVNS of the spine is rare, typically involving the posterior elements. The lytic radiographic appearance and fludeoxyglucose avidity of PVNS may mimic malignant bone lesions, including metastatic disease or myeloma. On T 1 and T 2 weighted, and gradient recalled echo MRI sequences, the low signal intensity may mimic giant cell tumour of the bone, gout or synovial amyloid deposits, thus posing a diagnostic dilemma for the imagers and the treating clinicians. We present a pathologically confirmed case of PVNS of the cervical spine in a 49-year-old female, detailing her imaging work-up, describing histopathological correlation and highlighting the lesion location and involvement of the joint space as useful imaging discriminators for diagnosing PVNS of the cervical spine.

Vertebral Artery Dissection and Cord Infarction - an Uncommon Cause of Brown-Séquard and Horner Syndromes.

This case report illustrates the neuroanatomy and neurovascular anatomy of the cervical spinal cord by exploring the pathophysiology of cervical cord infarction secondary to vertebral artery injury. The spinal cord is made up of several important tracts, including the dorsal column medial lemniscus system, corticospinal tracts, and the anterolateral system. Injury to one or more of these pathways can result in localizing neurological symptoms. Also contributing to the complexity of spinal vascular pathophysiology is the considerable variation to the cervical cord vascular anatomy. Understanding spinal cord function and neuroanatomy can aid in prompt diagnosis and management of ischemic cord lesions. In combination with a thorough clinical exam, advanced imaging techniques, such as diffusion tensor imaging, can not only localize the injury but also potentially help predict functional outcome.

Optic neuropathy caused by Propionibacterium acnes pachymeningitis.

We describe a patient with vision loss from an optic neuropathy caused by Propionibacterium acnes pachymeningitis. The patient's optic neuropathy was stabilized with appropriate antibiotic therapy.

Laryngeal actinomycosis.

Actinomyces odontolyticus, a component of normal human flora, has been implicated in cervicofacial actinomycosis, which most commonly involves the perimandibular soft tissues and is characterized by slowly progressive abscess and sinus tract formation. Actinomycosis has rarely been reported to involve the larynx, and the imaging findings of laryngeal involvement have not been reported. We present a case of laryngeal actinomycosis with findings on computed tomography, magnetic resonance imaging, and positron emission tomography.

Central nervous system and head and neck imaging findings of MYC/BCL2 "double hit" B cell lymphoma.

MYC/BCL2 double hit lymphoma (DHL) is a rare, recently recognised and highly aggressive subtype of non-Hodgkin lymphoma, with an affinity to involve the central nervous system and the head and neck either at initial presentation or during relapse. We present a case of 43-year-old woman with MYC/BCL2 DHL relapse in the nasopharynx with extensive spread to the neck, skull base, and the central nervous system. To our knowledge, this is the first reported case in the literature describing the MRI and CT scan findings and the profound pattern of disease involvement of this rare neoplasm.

Noncontrast computed tomographic Hounsfield unit evaluation of cerebral venous thrombosis: a quantitative evaluation.

INTRODUCTION: Our objective is to determine the utility of noncontrast Hounsfield unit values, Hounsfield unit values corrected for the patient's hematocrit, and venoarterial Hounsfield unit difference measurements in the identification of intracranial venous thrombosis on noncontrast head computed tomography. METHODS: We retrospectively reviewed noncontrast head computed tomography exams performed in both normal patients and those with cerebral venous thrombosis, acquiring Hounsfield unit values in normal and thrombosed cerebral venous structures. Also, we acquired Hounsfield unit values in the internal carotid artery for comparison to thrombosed and nonthrombosed venous structures and compared the venous Hounsfield unit values to the patient's hematocrit. RESULTS: A significant difference is identified between Hounsfield unit values in thrombosed and nonthrombosed venous structures. Applying Hounsfield unit threshold values of greater than 65, a Hounsfield unit to hematocrit ratio of greater than 1.7, and venoarterial difference values greater than 15 alone and in combination, the majority of cases of venous thrombosis are identifiable on noncontrast head computed tomography. CONCLUSION: Absolute Hounsfield unit values, Hounsfield unit to hematocrit ratios, and venoarterial Hounsfield unit value differences are a useful adjunct in noncontrast head computed tomographic evaluation of cerebral venous thrombosis.

Giant necrotic pituitary apoplexy.

Apoplexy of the pituitary gland is a rare complication of pituitary adenomas, involving hemorrhage with or without necrosis within the tumor. This condition may be either asymptomatic or may present with severe headache, visual impairment, ophthalmoplegia, and pituitary failure. Transsphenoidal surgery is the treatment of choice, and early intervention is usually required to ensure reversal of visual impairment. Reports of pituitary apoplectic lesions exceeding 60.0mm in diameter are very rare. A 39-year-old man with long-standing history of nasal congestion, decreased libido and infertility presented with a sudden onset of severe headache and diplopia. MRI of the head demonstrated a massive skull base lesion of 70.0 × 60.0 × 25.0mm, compatible with a giant pituitary macroadenoma. The lesion failed to enhance after administration of a contrast agent, suggesting complete necrotic apoplexy. Urgent surgical decompression was performed, and the lesion was resected via a transnasal transsphenoidal approach. Pathological analysis revealed evidence of necrotic pituitary apoplexy. At the 2 month follow-up, the patient had near-complete to complete resolution of his visual impairment. To the authors' knowledge, this report is unique as the patient demonstrated complete necrotic apoplexy and it underlines the diagnostic dilemma in such a case.