Comparison of MRI findings of hypothalamic-optic chiasmatic gliomas and craniopharyngiomas.

BACKGROUND: Differential diagnosis of hypothalamic-optic chiasmatic gliomas (HOCGs) and craniopharyngiomas on magnetic resonance imaging (MRI) can be quite challenging. PURPOSE: To compare the MRI features of HOCGs and cranipharyngiomas. MATERIAL AND METHODS: Patients diagnosed with HOCG or craniopharyngioma in histopathological evaluation between 2012 and 2022 and who underwent preoperative contrast-enhanced brain MRI were included. Various MRI features were retrospectively evaluated for each lesion: T2-weighted imaging and fluid attenuation inversion recovery hyperintensity, calcification, cystic change, T1-weighted (T1W) imaging hyperintensity of the cystic component, hemorrhage, involvement of sellar, suprasellar or other adjacent structures, lobulated appearance, presence of hydrocephalus, and contrast enhancement pattern. Apparent diffusion coefficient (ADC) values were also evaluated and compared. RESULTS: Among 38 patients included, 13 (34%) had HOCG and 25 (66%) had craniopharyngioma. Craniopharyngiomas had a significantly higher rate of cystic changes, calcification, and T1W imaging hyperintensity of the cystic component than HOCGs (P <0.05). Of HOCGs, 92% had chiasm involvement, 23% had optic nerve involvement, and 31% had brain stem involvement. On the other hand, chiasm involvement was observed in 8% of craniopharyngiomas, but none had optic nerve and/or brain stem involvement (P <0.05). While 62% (8/13) of HOCGs had diffuse homogeneous enhancement, 80% (20/25) of craniopharyngiomas had a diffuse heterogeneous enhancement pattern. Mean ADC values were significantly higher in craniopharyngiomas compared to HOCGs (2.1 vs. 1.6 ×10-3mm2/s, P <0.05). CONCLUSION: Although some neuroimaging findings may overlap, features such as presence of cyst and calcification, brain stem and optic pathway involvement, different enhancement patterns, and ADC values may be helpful in the differential diagnosis of HOCGs and craniopharyngiomas.

Delayed Enhancing White Matter Lesions, a Rare Complication After Stent-Assisted Coil Embolization: A Case Report.

BACKGROUND: Delayed enhancing white matter lesions are a rare complication that develops after endovascular treatment of cerebral aneurysms, the etiology of which remains unclear. METHODS AND RESULTS: We present a 52-year-old female patient who was symptomatic with a seizure-like condition and showed reversible cranial parenchymal changes with high-dose cortisone treatment after endovascular stent-assisted coil embolization for an unruptured aneurysm in the internal cerebral artery. CONCLUSIONS: Clinicians should be alert to this rare complication and should follow patients for a long time due to its fluctuating and long-term course.

Machine Learning May Be An Alternative To BIPSS In The Differential Diagnosis Of ACTH-Dependent Cushing's Syndrome.

OBJECTIVE: This study aimed to develop machine learning (ML) algorithms for the differential diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (CS) based on biochemical and radiological features. METHODS: Logistic regression algorithms were used for ML, and the area under the receiver operating characteristics curve (AUROC) was used to measure performance. We used Shapley Contributed Comments (SHAP) values, which help explain the results of the ML models to identify the meaning of each feature and facilitate interpretation. RESULTS: A total of 106 patients, 80 with Cushing's disease (CD) and 26 with ectopic ACTH syndrome (EAS), were enrolled in the study. The ML task was created to classify patients with ACTH-dependent CS into CD and EAS. The average AUROC value obtained in the cross-validation of the logistic regression model created for the classification task was 0.850. The diagnostic accuracy of the algorithm was 86%. The SHAP values indicated that the most important determinants for the model were the 2-day 2-mg dexamethasone suppression test, the > 50% suppression in the 8-mg high-dose dexamethasone test, late-night salivary cortisol, and the diameter of the pituitary adenoma. We have also made our algorithm available to all clinicians via a user-friendly interface. CONCLUSION: ML algorithms have the potential to serve as an alternative decision support tool to invasive procedures in the differential diagnosis of ACTH-dependent CS.

Dynamic (live) 3D roadmap as navigational tool in multiplug brain arteriovenous malformation embolization: technical note.

PURPOSE: Treatment of brain arteriovenous malformation (bAVM) includes microsurgical excision, stereotactic radiosurgery, endovascular embolization, or combination. With bAVM embolization, complete angiographic obliteration ranges from 12.5 to 51%, and higher total occlusion rate is seen in SM grades I to III, ranging from 96 to 100%. METHODS: In this paper, we illustrate the use of 3D rotational angiography and dynamic (live) 3D roadmap functions in endovascular treatment of bAVM. A single dynamic 3D roadmap or two dynamic 3D roadmaps obtained help tremendously in navigation of microcatheters and wires along the parent artery and bAVM feeders. RESULTS: This method eliminates the need for repeated 2D angiograms and roadmaps for new working projections every time the C-arm position is changed for cannulation of different feeders, thereby reducing radiation dose. No instances of misalignment error, vascular perforation, or thromboembolic phenomena were observed in the 21 embolization cases performed within the previous 2 years while utilizing this feature. CONCLUSION: The dynamic 3D roadmap is an extremely useful tool for multiple-feeder cannulation, by reducing the use of multiple 2D angiograms, providing intraprocedural live and adjustable 3D roadmap for better mental orientation to angioarchitecture of the bAVM, which further aids in the overall complete angiographic obliteration rate of bAVM in a single session especially in multiplug embolization technique.

Imaging findings of intraventricular pilocytic astrocytoma.

OBJECTIVE: The aim of this study is to present the clinical and imaging findings of 16 patients with intraventricular pilocytic astrocytomas (PAs). METHODS: 16 patients with histopathological diagnosis of intraventricular PA between February 2016 and January 2022 were evaluated retrospectively. Imaging and clinical findings of the patients, as well as apparent diffusion coefficient (ADC) measurements were analyzed. RESULTS: Of 16 patients, 8 (%50) were male and 8 (%50) were female. The mean age of the patients was 20.8 years (2-44 years range). The most common symptoms in the patients were headache and ataxia. The mean long-axis size of lesions was found to be 48.19 ± 21.59 (range, 15-92 mm). 9 out of 16 lesions (56.2%) were located in the fourth ventricle. The majority of the lesions were iso-hypointense in T1W and hyperintense in T2W images. The mean ADC value of PAs was 1.57 × 10-3 ± 0.2 mm2/s, while the mean thalamic ADC and white matter ADC values were found to be 0.78 × 10-3 ± 0.04 and 0.76 × 10-3 ± 0.06 mm2/s, respectively. There was a statistically significant difference between the ADC values obtained from the solid components of the lesions and the thalami/white matter (p < 0.001). CONCLUSION: PAs often originate from midline structures, however, they can also be located intraventricularly. Although intraventricular PAs are frequently seen in pediatric population, it should be kept in mind that they can also be seen in adults, albeit rarely. ADVANCES IN KNOWLEDGE: PA should be considered in the differential diagnosis of intraventricular neoplasms in case of high ADC values.

The efficacy of preoperative diffusion tensor tractography on surgical planning and outcomes in patients with intramedullary spinal tumor.

PURPOSE: The aim of this study was to investigate the efficacy of diffusion tensor tractography (DTT) of spinal cord on surgical planning and postoperative neurological outcomes in patients with spinal intramedullary tumors. METHODS: The study was conducted retrospectively from the radiological and clinical data of our hospital database. Patients with intramedullary spinal cord tumors who underwent diffusion tensor imaging for spinal cord lesions were selected between 2019 and 2022. Demographic characteristics and intraoperative neurophysiological monitoring data were evaluated. The McCormick scale was used to grade the pre- and postoperative neurological status of the patients. The tumoral lesions were categorized into 3 types according to the fiber course on DTT. RESULTS: Eleven patients were found to have radiological findings that were compatible with intramedullary tumor; eight (72.7%) of them ultimately underwent surgery following being approved as surgical candidates in the spinal diffusion tensor imaging studies. Six cases had Type 1, one case had Type 2, and 4 cases had Type 3 tumors according to the fiber course. All Type 1 tumors were classified as resectable and all of them were gross totally resected. Type 2 lesion that was rated as resectable by DTI was subtotally resected. Type 3 lesions were followed without surgery except the one with tumoral progression and neurological deficit. The postoperative neurological outcomes were compatible with intraoperative neurophysiological monitoring results. CONCLUSION: Diffusion tensor imaging and tractography may be beneficial regarding the selection of patients suitable for surgery and in the subsequent surgical planning.

Intra- and inter-observer reliability of Dias-Tachdjian classification in pediatric ankle fractures: do clinical experience and expertise matter?

The Dias-Tachdjian classification is the most commonly used system for the classification of pediatric ankle fractures, but its inter- and intra-observer reliability has not been studied in detail. Also, the impact of the clinician's experience and expertise on the reliability of this system is unknown. This study aimed: (1) to determine the intra- and inter-observer reliability of the Dias-Tachdjian classification and (2) to investigate the effect of the clinician's experience and expertise on the reliability of this system. Anteroposterior and lateral ankle radiographs of 56 children (34 male, 22 female) with ankle fractures, aged between 3 and 14 years, with open growth cartilages, were retrospectively identified and included in the study. Each patient radiograph was examined by 10 observers from two different specialties with different levels of clinical experience (two orthopedic surgeons with interest in pediatric orthopedics, three orthopedic surgeons with no interest in pediatric orthopedics, three orthopedic residents, and two radiology specialists) from two different specialties (orthopedics and radiology). All observers were then asked to classify pediatric ankle fractures at 6-week intervals per the Dias-Tachdjian classification system. Overall, intra-observer reliability as substantial to very good (κ = 0.77-0.95, P < 0.01), but inter-observer reliability as fair for both assessments (κ = 0.21, P < 0.01 and κ = 0.20, P < 0.01 for the first and second occasions, respectively). Inter-observer reliability among pediatric orthopedic surgeons as very good (κ = 0.90, 95% CI = 0.86-0.94, P < 0.01 and κ = 0.82, 95% CI = 0.71-0.93, P < 0.01 for the first and second occasions, respectively). Orthopedic surgeons with no special interest in pediatric orthopedics demonstrated substantial agreement in the first occasion (κ = 0.63, 95% CI = 0.53-0.72, P < 0.01) but moderate in the second one. Orthopedic residents exhibited moderate levels of agreement in each assessment period (κ = 0.58, 95% CI = 0.47-0.68, P < 0.01 and κ = 0.44, 95% CI = 0.37-0.51, P < 0.01 for the first and second occasion, respectively). Considering that the specialists dealing with pediatric orthopedics show very good consistency for Dias-Tachdjian classification, both within and between observers, consistency in the identification of the ankle fracture models increases as the interest in the field of pediatric orthopedics intensifies.

A new ventricular index based on coronal brain magnetic resonance images in patients with idiopathic normal pressure hydrocephalus.

BACKGROUND: The aim of this study was to assess the effectiveness of a new quantitative index for the diagnosis of idiopathic normal pressure hydrocephalus. METHODS: This retrospective study was conducted at Istanbul University Cerrahpasa Medical Faculty between January 2016 and November 2022. A total of 31 patients diagnosed with idiopathic normal pressure hydrocephalus were included in the study group and 48 patients were included in the control group. Measurement via the new Index was performed on a coronal section of magnetic resonance imaging at the level of the anterior commissure. RESULTS: The new Index's mean diagnostic performance was 1.16 ± 0.08 in the study group, significantly lower (p < 0.0001) than the mean of 1.43 ± 0.10 in the control group. When a cutoff value of 1.23 was used for the new index, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rates were 96.1%, 90.7%, 80.6%, 98%, and 91.3%, respectively. DISCUSSION: The new Index described here is an effective, feasible, reproducible, highly sensitive, and specific quantitative method that can contribute to the improved diagnosis of patients with idiopathic normal pressure hydrocephalus.

Magnetic resonance perfusion imaging findings following flow diversion in patients with complex middle cerebral artery bifurcation aneurysms: a single-center analysis regarding the jailed cortical branches.

BACKGROUND: Flow diverter (FD) devices provide a safe and effective treatment option especially for wide-necked intracranial aneurysms. One of the main concerns in patients treated with FD devices is patency of arterial branches jailed by the stent. However, there are no long-term data from magnetic resonance perfusion (MRP) studies regarding jailed branches. In this study we aimed to reveal the MRP findings in patients with jailed middle cerebral artery (MCA) cortical branches during long-term follow-up after flow diversion. METHODS: Patients who underwent FD stent treatment for MCA aneurysms with a resulting jailed cortical branch were included. Follow-up clinical, angiographic, and MRP examination findings were recorded. Different MRP parameters were measured in the MCA territory regarding the jailed branches. RESULTS: Eighteen patients treated endovascularly with flow diversion for a total of 20 MCA aneurysms were included. At angiographic follow-up (median 35 months, range 7-95 months) complete occlusion was observed in 13 (65%) aneurysms and partial occlusion was observed in 6 (30%). The mean transit time (MTT) prolongation, MTT ratio, time-to peak (TTP) prolongation, and TTP ratio were 1.34, 1.20, 1.18, and 1.06 s, respectively, when compared with the contralateral side in the MCA territory. MTT, TTP, and cerebral blood volume values of the patients showed statistically significant differences compared with the contralateral side (P<0.05). CONCLUSIONS: Flow diversion treatment of complex bifurcation aneurysms can be effective and safe. MRP examination may reveal perfusion changes in the territory vascularized via a jailed branch, and these changes are rarely accompanied by clinical findings.

Evaluation of short- and long-term results of Y-stent-assisted coiling with Leo stents in endovascular treatment of wide-necked intracranial bifurcation aneurysms.

PURPOSE: This study aimed to evaluate the feasibility, safety, and efficacy of Y-stent-assisted coiling (Y-SAC) using LEO Baby® stents in treating of bifurcation aneurysms. METHODS: Patients who underwent Y-SAC using a braided stent (LEO Baby®, Montmorency, France) for wide-necked intracranial aneurysms between 2009 and 2019 and whose radiological and clinical follow-up data for at least 6 months could be obtained were evaluated. Data were obtained from patient records and analyzed retrospectively. RESULTS: We evaluated 111 patients with a mean age of 56.0 ± 10.8 years (range, 25-88 years). Most of the aneurysms were detected incidentally. Three patients had ruptured aneurysms. LEO Baby deployment and coiling were successful in all patients. Immediate aneurysm occlusion rates were determined as modified Raymond-Roy classification (mRRC) I 95.5% (n = 106), mRRC II 3.6% (n = 4), mRRC IIIa 0.9% (n = 1). In the sixth month, aneurysm occlusion rates were found to be complete and nearly complete in all patients (mRRC I 94.6%, n = 105 and mRRC II 4.5%; n = 5, respectively). Follow-up data of 91 patients for > 2 years were obtained. Of these, 88 had MRRCI obstruction and 3 had MRRC II obstruction. The overall complication rate was 4.8%, and one patient died during the post-procedural follow-up. CONCLUSION: The long-term follow-up results of Y-stenting with LEO Baby revealed that it provides stable closure of the aneurysm sac while preserving the main arterial structures. Therefore, it is a safe, durable, and effective method for treating wide-necked and complex bifurcation aneurysms.

Spontaneous internal carotid artery dissection in a child diagnosed by high resolution vessel wall MRI.

Craniocervical dissection is one of the most common causes of stroke in children. Although the most common cause of dissection is trauma, spontaneous dissections in which no cause can be revealed may also occur. The diagnosis of this type of dissection in children can be challenging with the preferred non-invasive imaging methods (MRA, CTA). Intracranial vessel wall imaging is a promising novel method for identifying specific signs of dissection. We report an 11-year-old girl with spontaneous ICA dissection, whose diagnosis was confirmed by an MRI of the intracranial vessel wall. Vessel wall imaging has contributed substantially to the diagnosis and follow-up of this case.

Efficacy of Dural Sinus Quantitative Measurements in Idiopathic Intracranial Hypertension : A Practical Diagnostic Feature.

BACKGROUND AND PURPOSE: This study aimed to investigate the potential contribution of quantitative measurements of dural venous sinuses to the diagnosis of idiopathic intracranial hypertension (IIH) and the relationship between IIH and dural venous sinus dimensions on 3D post-gadolinium T1-weighted magnetic resonance (MR) images. MATERIAL AND METHODS: A total of 129 individuals (57 IIH patients and 72 controls) who complained of headache and underwent both magnetic resonance venography (MRV) and precontrast/postcontrast 3D T1-weighted MR imaging between 2018 and 2021 were included in this retrospective study. Dural venous sinus and jugular vein diameters were measured in all cases using post-gadolinium 3D T1 TFE images. The presence of transverse sinus (TS) hypoplasia and occipital sinus variation, the number and size of arachnoid granulations in the TS, and the presence of brain parenchymal herniation were also evaluated. Cut-off values that maximized accurate diagnosis of IIH were established on the receiver operating characteristic curve. The sensitivity and specificity of the diagnosis of IIH based on quantitative measurements of the dural sinus were calculated. RESULTS: The ratios of the maximum to minimum TS diameters and the minimum TS diameters to minimum sigmoid sinus (SS) diameters were significantly higher in IIH patients than in the control group (p < 0.001). The diagnostic sensitivity and specificity values of TSmax/TSmin and TSmin sum/SSmin sum parameters for the detection of IIH were 84.2%, 84.7% and 83.3%, 84.2%, respectively. CONCLUSION: Practical measurements from multiplanar T1 sequences can be useful for both quantitative assessment and overcoming misinterpretation due to anatomical variation.

Prediction of Molecular Subtypes Using Superb Microvascular Imaging and Shear Wave Elastography in Invasive Breast Carcinomas.

RATIONALE AND OBJECTIVES: To investigate the efficacy of the advanced imaging methods, superb microvascular imaging (SMI) and shear wave elastography (SWE) in predicting molecular subtypes in invasive breast carcinomas. MATERIALS AND METHODS: A total of 210 biopsy-proven breast carcinomas in 200 patients who underwent ultrasound (US) imaging with SMI and SWE were included in this study. Quantitative analyses were performed using mean elasticity (Emean) score by SWE and vascular index (VI) by SMI. For qualitative assessment of microvascularity, first, lesions were graded according to Adler's classification in four types. Then, a new morphological model was used to classify the microvascular architecture into six patterns: type one, no signal; type two, penetrant; type three, rim-like; type four, dot-like/linear/regional; type five, wheel-like and type six, irregular signals. The correlation between these variables and molecular subtypes, nuclear grade, the Ki-67 levels and axillary status was investigated. RESULTS: The average VI and Emean values were relatively higher in non-luminal subtypes (VI, p = 0.002; Emean, p > 0.05). The two microvascularisation models were significantly able to differentiate the molecular subtypes according to the Kruskal Wallis test (p < 0.05). Rim-like, penetrant and regional patterns were primarily observed in luminal subtypes. The dominant pattern in non-luminal subtypes was wheel-like pattern. VI, Emean, Adler's classification and morphological vascularisation model were not significantly correlated with the nuclear grade, Ki-67 index or axillary status. CONCLUSION: The proposed microvascular categorization model may be more valuable in predicting molecular subtypes of breast carcinomas compared to VI and Emean and may contribute to the management of breast carcinomas as a non-invasive variable.

Potential Association Between COVID-19 Vaccination and Facial Palsy: Three Cases With Neuroimaging Findings.

Acute onset Facial palsy was reported in four vaccinated participants in the BNT162b2 (Pfizer-BioNTech) vaccine clinical trials published on December 10, 2020. So far, few cases of Facial palsy among the mRNA vaccine groups have been previously documented in the literature. Facial palsy is cited as medically attended adverse event following immunization on April 12, 2021, after the first dose of the approved Pfizer-BioNTech COVID-19 vaccines for preventive immunization for SARS-CoV-2 is administrated to the population in Turkey. This study is aimed to describe clinical and magnetic resonance imaging features of three patients, who developed acute onset peripheral facial paralysis after administration of the BNT162b2 vaccine, without any previous medical condition. The first patient presented with right sided facial palsy within the same day following the vaccine was administrated, while the second patient presented with left sided facial palsy 2 months after vaccination. The third patient, on the other hand, presented with right sided facial palsy and abducens nerve (CN VI) paralysis two days after vaccine was administrated.

Comparison and ensemble of 2D and 3D approaches for COVID-19 detection in CT images.

Detecting COVID-19 in computed tomography (CT) or radiography images has been proposed as a supplement to the RT-PCR test. We compare slice-based (2D) and volume-based (3D) approaches to this problem and propose a deep learning ensemble, called IST-CovNet, combining the best 2D and 3D systems with novel preprocessing and attention modules and the use of a bidirectional Long Short-Term Memory model for combining slice-level decisions. The proposed ensemble obtains 90.80% accuracy and 0.95 AUC score overall on the newly collected IST-C dataset in detecting COVID-19 among normal controls and other types of lung pathologies; and 93.69% accuracy and 0.99 AUC score on the publicly available MosMedData dataset that consists of COVID-19 scans and normal controls only. The system also obtains state-of-art results (90.16% accuracy and 0.94 AUC) on the COVID-CT-MD dataset which is only used for testing. The system is deployed at Istanbul University Cerrahpasa School of Medicine where it is used to automatically screen CT scans of patients, while waiting for RT-PCR tests or radiologist evaluation.

Clinical outcomes of geriatric patients with COVID-19: review of one-year data.

AIMS: In this study, we aimed to reveal mortality rates and factors affecting survival in geriatric patients infected with COVID-19. METHODS: This is a retrospective study of 873 geriatric patients with COVID-19 who were hospitalized between March 11, 2020 and March 11, 2021. Demographic, clinical, laboratory data, and treatment options were obtained from electronic medical records. Multivariate logistic regression was used to explore the risk factors for in-hospital death. RESULTS: During the specified period, 643 patients were discharged, and 230 patients died in the hospital. The mean age was 75.08 ± 7.39 years (mean ± SD) and 51.8% were males. We found that older age (≥ 85), polypharmacy, dyspnea, abnormal thorax computed tomography (CT), lower doses of anticoagulation, and high values of white blood cell, aspartate aminotransferase, C-reactive protein, lactate dehydrogenase, ferritin were associated with a significant increase in mortality (P < 0.001 for all). Although all of these values were significant in multivariate logistic regression analysis, the most important ones were dyspnea (Odds ratio (OR) 57.916, 95% confidence interval (CI) 23.439-143.104, P < 0.001), polypharmacy (OR 6.782, 95% CI 3.082-14.927, P < 0.001), and thorax CT classification (typical; OR 9.633, 95% CI 2.511-37.122, P < 0.001). CONCLUSION: Older age, polypharmacy, dyspnea, and abnormal thorax CT were the most significant mortality criteria and in addition appropriate anticoagulant use was associated with reduced mortality. Identifying the risk factors to predict mortality in older adults with COVID-19 is important to treat future cases successfully.

Case report: Spinal drop metastasis of IDH-mutant, 1p/19q-codeleted oligodendroglioma.

Background: Symptomatic spinal metastases of oligodendroglioma are rare. Moreover, none of the previously published cases demonstrated the typical IDH mutation and 1p/19q-codeletion for this glial tumor. This case presents an IDH mutant, 1p/19q-codeleted oligodendroglioma with multiple spinal drop metastases. Case description: We report a case of a 55-year-old woman with left frontal grade 3 oligodendroglioma diagnosed 3 years ago. No tumor recurrence was observed in post-operative follow-up MRI examinations. However, she was admitted to our institution again with severe low back pain. Gadolinium enhanced MRI of the spine revealed an intradural, extramedullary metastatic lesion between T11-L1 levels and multiple enhancing metastatic tumor deposits around cauda equine roots between L4-S1. T11-T12 midline laminectomy was performed and gross total resection of metastatic lesions was achieved. Final histological diagnosis of the spinal lesions was WHO Grade 3 Oligodendroglioma, IDH-mutant, 1p/19q-codeleted. Conclusion: This case is the first molecularly-defined spinal metastatic oligodendroglioma. The possibility of drop metastasis should be kept in mind in oligodendroglioma patients with spinal cord-related symptoms. There is no standard approach for the diagnosis and treatment of spinal metastases of this type of glial tumor.

Endovascular management of anterior falcotentorial dural arteriovenous fistulas: importance of functionality of deep venous system and existence of accompanying choroidal arteriovenous malformation.

BACKGROUND: Anterior falcotentorial junction dural arteriovenous fistulas (AFDAVFs) are the most deeply located and most complex type of tentorial fistula due to their location and vascular anatomy. We aimed to make new angiographic definitions of AFDAVF nidus and functionality of the deep venous system of the brain and thereby provide a safer approach for endovascular treatment. METHODS: We retrospectively examined 18 patients with AFDAVF who received endovascular treatment at our neuroradiology department between June 2002 and May 2019. Pre- and post-treatment clinical assessments were performed using the modified Rankin Scale. AFDAVF niduses were defined as mixed-type or pure-dural-type on the basis of whether choroidal arteriovenous malformation was coexisting or not, respectively. The deep venous system was denoted as functional or nonfunctional. RESULTS: We included 13 men and 5 women (mean (range) age, 47.2 (31-62) years). We evaluated 15 patients with pure-dural-type AFDAVFs and three with mixed-type AFDAVFs. Complete occlusion of the fistula was achieved in 15/18 patients. Three patients had transient neurologic symptoms. In two patients these were due to mild thalamic ischemia and in the third patient was due to tectal venous ischemia, all in mixed-type AFDAVF. One patient also developed Parinaud syndrome due to compression of the tectal plate by a thrombosed large vein of Galen. No patients died or developed permanent morbidity. CONCLUSION: Evaluating AFDAVFs as described here using our new subtyping model will help improve analysis of the malformation and development of a safer endovascular strategy, and hence may prevent periprocedural complications and improve treatment safety.

Posterior Reversible Encephalopathy Syndrome in a Pediatric COVID-19 Patient.

Novel coronavirus disease 2019 is a viral infectious disease which commonly involve the lungs with primarily radiologic manifestations of atypical or organizing pneumonia. It can cause multisystemic involvement including central nervous system symptoms. One of these neurologic manifestations is posterior reversible encephalopathy syndrome (PRES). It is suggested that the increased levels of cytokines and inflammatory mediators in the course of the disease are responsible for cerebrovascular endothelial dysfunction and disruption of the blood-brain barrier. To the best of our knowledge, no pediatric PRES has been reported related to coronavirus disease 2019. Here, we present a pediatric PRES case associated with severe acute respiratory syndrome coronavirus 2 infection.