The potential of 3D models and augmented reality in teaching cross-sectional radiology.

What was the educational challenge?The complexity and variability of cross-sectional imaging present a significant challenge in imparting knowledge of radiologic anatomy to medical students.What was the solution?Recent advancements in three-dimensional (3D) segmentation and augmented reality (AR) technology provide a promising solution. These advances allow for the creation of interactive, patient-specific 3D/AR models which incorporate multiple imaging modalities including MRI, CT, and 3D rotational angiography can help trainees understand cross-sectional imaging.How was the solution implemented?To create the model, DICOM files of patient scans with slice thicknesses of 1 mm or less are exported to a computer and imported to 3D Slicer for registration. Once registered, the files are segmented with Vitrea software utilizing thresholding, region growing, and edge detection. After the creation of the models, they are then imported to a web-based interactive viewing platform and/or AR application.What lessons were learned that are relevant to a wider global audience?Low-resource 3D/AR models offer an accessible and intuitive tool to teach radiologic anatomy and pathology. Our novel method of creating these models leverages recent advances in 3D/AR technology to create a better experience than traditional high and low-resource 3D/AR modeling techniques. This will allow trainees to better understand cross-sectional imaging.What are the next steps?The interactive and intuitive nature of 3D and AR models has the potential to significantly improve the teaching and presentation of radiologic anatomy and pathology to a medical student audience. We encourage educators to incorporate 3D segmentation models and AR in their teaching strategies.

Endovascular Treatment of Arteriovenous Malformations of the Head and Neck: Focus on the Yakes Classification and Outcomes.

PURPOSE: To evaluate endovascular treatment of head and neck arteriovenous malformations (AVMs) based on the Yakes AVM classification and correlate treatment approach with clinical and angiographic outcomes. MATERIALS AND METHODS: A retrospective single-center study was performed in patients who underwent endovascular treatment of head and neck AVMs between January 2005 and December 2017. Clinical and operative records, imaging, and postoperative courses of patients were reviewed. Clinical stage was determined according to the Schobinger classification. AVM architecture and treatment approaches were determined according to the Yakes classification. Primary outcomes were clinical and angiographic treatment success rates and complication rates, with analysis according to the Yakes classification. RESULTS: A total of 29 patients (15 females) were identified, with a mean age of 30.6 years. Downgrading of the Schobinger clinical classification was achieved in all patients. Lesions included 8 Yakes type IIa, 5 type IIb, 1 type IIIa and IIIb, and 14 type IV. Lesions were treated using an intra-arterial, nidal, or transvenous approach, using ethanol and liquid embolic agents. Arteriovenous shunt eradication of >90% was achieved in 22 of 28 patients (79%), including 9 of 13 (69%) of Yakes type IV lesions and 13 of 15 (87%) of the other types. There were 5 significant complications in 79 procedures (6%), including 4 of 50 (8%) in Yakes type IV lesions. CONCLUSIONS: Schobinger stage was downgraded in all patients. Arteriovenous shunt eradication of >90% was achieved in most patients. Yakes type IV lesions required more sessions, and shunt eradication was higher in the Yakes II and III groups.

CT Imaging Computed Tomography/Computed Tomography Angiography/Perfusion in Acute Ischemic Stroke and Vasospasm.

Computed tomography (CT), CT angiography (CTA), and CT perfusion (CTP) play crucial roles in the comprehensive evaluation and management of acute ischemic stroke, aneurysmal subarachnoid hemorrhage (SAH), and vasospasm. CTP provides functional data about cerebral blood flow, allowing radiologists, neurointerventionalists, and stroke neurologists to more accurately delineate the volume of core infarct and ischemic penumbra allowing for patient-specific treatment decisions to be made. CTA and CTP are used in tandem to evaluate for vasospasm associated with aneurysmal SAH and can help provide an insight into the physiologic impact of angiographic vasospasm, better triaging patients for medical and interventional treatment.

The interplay among a dental procedure, infective endocarditis, and an acute ischemic stroke.

BACKGROUND: This case report highlights the rare association among a dental procedure, infective endocarditis, and an acute ischemic stroke. CASE DESCRIPTION: A 54-year-old woman who experienced an acute ischemic stroke 5 weeks after a tooth extraction is described. The initial symptoms of this patient included mild to moderate word-finding difficulty and right facial droop. Computed tomographic angiography revealed a left M1 segment middle cerebral artery occlusion (thrombolysis in cerebral infarction scale, 0) with reconstitution of the distal middle cerebral branches through arterial collaterals. After initial administration of tissue plasminogen activator, endovascular thrombectomy was successfully performed with thrombolysis in cerebral infarction scale 3 (complete) recanalization. After the procedure, the patient showed improvement in language and neurologic deficits. Imaging showed multifocal, bilateral, cortical, and deep brain hemorrhages. Blood cultures grew Streptococcus mitis, ultimately leading to the diagnosis of endocarditis. Echocardiographic imaging revealed moderate to severe aortic insufficiency, a mitral valve vegetation, and mild mitral valve regurgitation. After evaluation by the cardiothoracic surgery team, the patient was discharged with intravenous antibiotics and short-term outpatient follow-up with the cardiothoracic surgery team. PRACTICAL IMPLICATIONS: Dental procedures, although generally safe, can introduce oral bacteria into the bloodstream, leading to bacterial seeding of cardiac valves and subsequent infective endocarditis. Recognizing infective endocarditis subsequent to a dental procedure, including a tooth extraction, as a potential cause of an acute ischemic stroke is vital so that prompt treatment can be initiated.

Newer Updates in Pediatric Vascular Diseases.

Pediatric neurovascular pathology directly involves or is in close proximity to the central nervous system (CNS). These vascular pathologies can occur in isolation or in association with broader syndromes. While some vascular pathologies are unique to the pediatric population, the full spectrum of adult neurovascular lesions can also affect children however, may present differently both clinically and on diagnostic imaging. Non-invasive (Ultrasound, CT, MRI) imaging plays a critical role in the diagnosis, treatment planning, and follow-up of vascular lesions involving the CNS. The modality can be chosen based on the age of the child, urgency of diagnosis, and local availability. Each modality has sensitivities and specificities which vary based on the location and imaging findings of a specific neurovascular pathology. In addition to non-invasive options, digital subtraction angiography (DSA) may be used as both a diagnostic and therapeutic imaging method for pediatric vascular lesions of the central nervous system. The diagnosis and management of pediatric cerebrovascular disease requires the close collaboration between pediatricians and pediatric specialists including neuroradiologists, neurologists, neurosurgeons, cardiologists, neurointerventionalists, and anesthesiologists among others. A detailed understanding of imaging findings, natural history, and treatment options is essential to guide and monitor imaging and treatment. The goal of this review is to provide the reader with an overview on pediatric neurovascular pathologies, provide examples of pathognomonic imaging findings, and present a brief review of endovascular treatment options, if applicable.

Successful retrieval of ethylene vinyl alcohol (EVOH) from the left middle cerebral artery during preoperative embolization of a juvenile nasopharyngeal angiofibroma (JNA).

Preoperative embolization of a juvenile nasopharyngeal angiofibroma (JNA) using ethyl vinyl alcohol (EVOH) is an effective adjunctive treatment prior to surgical resection. While liquid embolic agents are safe to use, we present a unique case involving the migration of EVOH into the left middle cerebral artery (MCA) through an external carotid artery-internal carotid artery (ECA-ICA) collateral during preoperative embolization using a dual-lumen balloon catheter. A 16-year-old male presented with left-sided nasal congestion, new nasal intonation in voice, and epistaxis. CT imaging showed a hypervascular mass centered within the left posterior nasal cavity and nasopharynx with expansion of the ipsilateral sphenopalatine foramen. A JNA was diagnosed, and preoperative embolization was performed prior to surgical resection. During the embolization procedure, EVOH migrated into the intracranial circulation through a hypertrophied ECA-ICA collateral. Angiography confirmed embolic material at the left MCA bifurcation. The embolic material was successfully removed using a balloon guide catheter and stentriever. This case is presented to highlight potential complications and rescue techniques used in the setting of non-target embolization occurring during JNA embolization.

Iatrogenic pseudoaneurysm of the middle meningeal artery during embolization of bilateral chronic subdural hematomas.

Summary/AbstractMiddle meningeal artery embolization has become an important treatment option for chronic subdural hematomas. While the treatment is safe, we present a unique case of development of an iatrogenic middle meningeal artery pseudoaneurysm during endovascular embolization with use of a dual-lumen balloon catheter used for injection of a liquid embolic agent. A 62-year-old man on Coumadin for portal vein thrombosis presented to the hospital with headache and supratherapeutic INR. Imaging revealed bilateral acute on chronic subdural hematomas. Given his medical comorbidities he underwent endovascular middle meningeal artery embolization. During the embolization, angiography revealed a pseudoaneurysm of the middle meningeal artery related to use of a dual-lumen balloon catheter. This pseudoaneurysm was successfully treated with ethylene vinyl alcohol embolization. Intracranial pseudoaneurysm related to balloon catheter use is a rare cause of iatrogenic pseudoaneurysm and could lead to life-threatening intracranial bleeding. Therefore, recognition and timely treatment are important.

1D + 1D → 1D polyrotaxane, 2D + 2D → 3D interpenetrated, and 3D self-penetrated divalent metal terephthalate bis(pyridylformyl)piperazine coordination polymers.

Divalent metal coordination polymers containing terephthalate (tere) and bis(4-pyridylformyl)piperazine (bpfp) show diverse and interesting two-dimensional (2D) interpenetrated, three-dimensional (3D) self-penetrated, or one-dimensional (1D) polyrotaxane topological features. Isostructural {[M(tere)(bpfp)(H(2)O)(2)]•4H(2)O}(n) phases (1, Zn; 2, Co) exhibit mutually inclined 2D + 2D → 3D interpenetration of gridlike layers. {[Cd(4)(tere)(4)(bpfp)(3)(H(2)O)(2)]·8H(2)O}(n) (3) possesses a novel 3,4,8-connected trinodal self-penetrated network with (4.6(2))(2)(4(2)6(16)8(7)10(3))(4(2)6(4))(2) topology. [Zn(2)Cl(2)(tere)(bpfp)(2)](n) (4) is the first example of a 1D + 1D → 1D polyrotaxane coordination polymer, to the best of our knowledge. Metal coordination geometry plays a crucial role in dictating the overall dimensionality in this system. Thermal decomposition behavior and luminescent properties of the d(10) configuration metal derivatives are also presented herein.

Endoscopic and fluoroscopic-guided closure of the eustachian tube using a biliary cytology brush and liquid embolic agent for a persistent CSF leak after schwannoma resection.

Vestibular schwannoma is a known cause of progressive sensorineural hearing loss. Treatment options include observation, radiation therapy and surgical resection. Cerebrospinal fluid (CSF) fistula is a known postsurgical complication that can lead to CSF otorrhoea, rhinorrhoea or CSF leakage from the surgical wound. We present a case report of a patient who underwent vestibular schwannoma resection and postoperatively developed CSF rhinorrhoea, which was refractory to multiple attempts at surgical repair. This was successfully treated under endoscopic and fluoroscopic guidance using a biliary cytology brush to disrupt the surface of the eustachian tube followed by injection of n-Butyl cyanoacrylate.

Skull Base Neurointerventional Techniques.

Neurodiagnostic and neurointerventional radiology (NIR) play a central role in the diagnosis and treatment of skull base disorders. Noninvasive imaging modalities, including computed tomography and magnetic resonance imaging, are important in lesion localization, evaluation of lesion extent, and diagnosis, but cannot always be definitive. Image-guided skull base biopsy and percutaneous and endovascular treatment options are important tools in the diagnosis and treatment of head, neck, and skull base disorders. NIR plays an important role in the treatment of vascular disorders of the skull base. This article summarizes the imaging evaluation and interventional therapies pertinent to the skull base.

Assessing early erythrolysis and the relationship to perihematomal iron overload and white matter survival in human intracerebral hemorrhage.

AIMS: Iron released from lysed red blood cells within the hematoma plays a role in intracerebral hemorrhage (ICH)-related neurotoxicity. This study utilizes magnetic resonance imaging (MRI) to examine the time course, extent of erythrolysis, and its correlation with perihematomal iron accumulation and white matter loss. METHODS: The feasibility of assessing proportional erythrolysis using T2* MRI was examined using pig blood phantoms with specified degrees of erythrolysis. Fifteen prospectively enrolled ICH patients had MRIs (3-Tesla) at days 1-3, 14, and 30 (termed early, subacute, and late periods, respectively). Measurement was performed on T2*, 1/T2*, and fractional anisotropy (FA) maps. RESULTS: Pig blood phantoms showed a linear relationship between 1/T2* signal and percent erythrolysis. MRI on patients showed an increase in erythrolysis within the hematoma between the early and subacute phases after ICH, almost completing by day 14. Although perihematomal iron overload (IO) correlated with the erythrolysis extent and hematoma volume at days 14 and 30, perihematomal white matter (WM) loss significantly correlated with both, only at day 14. CONCLUSION: MRI may reliably assess the portion of the hematoma that lyses over time after ICH. Perihematomal IO and WM loss correlate with both the erythrolysis extent and hematoma volume in the early and subacute periods following ICH.

Poly[[µ(4)-bis-(4-pyridyl-carbon-yl)piperazine-κN:N':O:O']bis-(thio-cyanato-κN)cobalt(II)].

In the title compound, [Co(NCS)(2)(C(16)H(16)N(4)O(2))](n), the octa-hedrally coordinated Co(II) ion lies on a crystallographic inversion center, with trans isothio-cyanate ligands. Pyridyl N-donor atoms and formyl O-donor atoms from exotetra-dentate bis-(4-pyridyl-carbon-yl)piperazine (4-bpfp) ligands link the Co(NCS)(2) units into a [Co(NCS)(2)(4-bpfp)](n) coordination polymer layer that is oriented parallel to (101). The layers stack along [010] to construct the pseudo-three-dimensional structure.