Neuroimaging of Neonatal Stroke: Venous Focus.

Perinatal venous infarcts are underrecognized clinically and at imaging. Neonates may be susceptible to venous infarcts because of hypercoagulable state, compressibility of the dural sinuses and superficial veins due to patent sutures, immature cerebral venous drainage pathways, and drastic physiologic changes of the brain circulation in the perinatal period. About 43% of cases of pediatric cerebral sinovenous thrombosis occur in the neonatal period. Venous infarcts can be recognized by ischemia or hemorrhage that does not respect an arterial territory. Knowledge of venous drainage pathways and territories can help radiologists recognize characteristic venous infarct patterns. Intraventricular hemorrhage in a term neonate with thalamocaudate hemorrhage should raise concern for internal cerebral vein thrombosis. A striato-hippocampal pattern of hemorrhage indicates basal vein of Rosenthal thrombosis. Choroid plexus hemorrhage may be due to obstruction of choroidal veins that drain the internal cerebral vein or basal vein of Rosenthal. Fan-shaped deep medullary venous congestion or thrombosis is due to impaired venous drainage into the subependymal veins, most commonly caused by germinal matrix hemorrhage in the premature infant and impeded flow in the deep venous system in the term infant. Subpial hemorrhage, an underrecognized hemorrhage stroke type, is often observed in the superficial temporal region, and its cause is probably multifactorial. The treatment of cerebral sinovenous thrombosis is anticoagulation, which should be considered even in the presence of intracranial hemorrhage. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

MRI and PSMA PET/CT of Biochemical Recurrence of Prostate Cancer.

Prostate cancer may recur several years after definitive treatment, such as prostatectomy or radiation therapy. A rise in serum prostate-specific antigen (PSA) level is the first sign of disease recurrence, and this is termed biochemical recurrence. Patients with biochemical recurrence have worse survival outcomes. Radiologic localization of recurrent disease helps in directing patient management, which may vary from active surveillance to salvage radiation therapy, androgen-deprivation therapy, or other forms of systemic and local therapy. The likelihood of detecting the site of recurrence increases with higher serum PSA level. MRI provides optimal diagnostic performance for evaluation of the prostatectomy bed. Prostate-specific membrane antigen (PSMA) PET radiotracers currently approved by the U.S. Food and Drug Administration demonstrate physiologic urinary excretion, which can obscure recurrence at the vesicourethral junction. However, MRI and PSMA PET/CT have comparable diagnostic performance for evaluation of local recurrence after external-beam radiation therapy or brachytherapy. PSMA PET/CT outperforms MRI in identifying recurrence involving the lymph nodes and bones. Caveats for use of both PSMA PET/CT and MRI do exist and may cause false-positive or false-negative results. Hence, these techniques have complementary roles and should be interpreted in conjunction with each other, taking the patient history and results of any additional prior imaging studies into account. Novel PSMA agents at various stages of investigation are being developed, and preliminary data show promising results; these agents may revolutionize the landscape of prostate cancer recurrence imaging in the future. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Turkbey in this issue. The slide presentation from the RSNA Annual Meeting is available for this article.

Comparison of Olfactory Cleft Width and Volumes in Patients with COVID-19 Anosmia and COVID-19 Cases Without Anosmia.

INTRODUCTION: The aim of this study was to assess the relationship between olfactory cleft width/volume and COVID-19-related anosmia. METHODS: This study consisted of PCR-proven COVID-19 patients. Cases with COVID-19-related anosmia constituted Group 1 and cases without any olfactory dysfunction (OD) throughout COVID-19 infection or after recovery constituted Group 2. A total of 50 patients were included in the study, comprising 24 cases in Group 1 and 26 cases in Group 2. Group 1 patients underwent a 4-item-odor identification test during active symptoms and a Sniffin' Sticks test after reconversion of PCR results to negative. All patients in Group 2 also underwent the Sniffin' Stick test to document normosmia. All cases had paranasal sinus CT performed. Olfactory cleft widths and olfactory volumes were measured. The differences in width and volume between groups and the correlation with odor test scores (threshold-discrimination-identification [TDI]) were calculated. In addition, regression analyzes analysis was performed for cleft widths, volumes, and TDI scores according to age. RESULTS: Olfactory cleft widths and olfactory volumes were significantly higher in Group 1 than those in Group 2 (p = 0.001; p < 0.01). There was a significant negative correlation between total TDI scores and olfactory cleft widths and total olfactory volumes (r = -0.665; r = -0.731, respectively). Patients younger than 40 years of age had significantly higher right olfactory cleft width, left olfactory cleft width, and olfactory cleft volume than those in patients older than 40 years of age (p = 0.004, p = 0.005, p = 0.003; p < 0,01, respectively). However, patients younger than 40 years of age had a significantly lower total TDI score and in all other values individually (t-d-i) than those in patients older than 40 years of age (p = 0.004; p < 0.01). CONCLUSION: Patients with COVID-19-related OD had larger olfactory cleft width and volumes than those without OD in this study. Total TDI score was found to be inversely correlated with cleft width and volume.

Relationship between disease severity and serum IL-6 levels in COVID-19 anosmia.

BACKGROUND: An association between IL-6 levels and cytokine storm syndrome in COVID-19 patients has been suggested. Cases with higher IL-6 levels have more rapid progression and a higher complication rate. On the other hand, COVID-19 cases with anosmia have a milder course of the disease. OBJECTIVE: We aimed to investigate whether there is a relationship between serum IL-6 levels and presence of anosmia in COVID-19 patients. METHODS: Patients with a confirmed diagnosis of COVID-19 based on laboratory (PCR) were stratified into two groups based on presence of olfactory dysfunction (OD). In all cases with and without anosmia; psychophysical test (Sniffin' Sticks test) and a survey on olfactory symptoms were obtained. Threshold (t) - discrimination (d) - identification (i), and total (TDI) scores reflecting olfactory function were calculated. Clinical symptoms, serum IL-6 levels, other laboratory parameters, and chest computed tomography (CT) findings were recorded. RESULTS: A total of 59 patients were included, comprising 23 patients with anosmia and 36 patients without OD based on TDI scores. Patients with anosmia (41.39 ± 15.04) were significantly younger compared to cases without anosmia (52.19 ± 18.50). There was no significant difference between the groups in terms of comorbidities, smoking history, and symptoms including nasal congestion and rhinorrhea. Although serum IL-6 levels of all patients were above normal values (7 pg/mL), patients with anosmia had significantly lower serum IL-6 levels (16.72 ± 14.28 pg/mL) compared to patients without OD (60.95 ± 89.33 pg/mL) (p = 0.026). CONCLUSION: Patients with COVID-19 related anosmia tend to have significantly lower serum levels of IL-6 compared to patients without OD, and the lower IL-6 levels is related to milder course of the disease. With the effect of low cytokine storm and IL-6 level, it may be said that anosmic cases have a milder disease in COVID-19.

The temporal course of COVID-19 anosmia and relation to other clinical symptoms.

OBJECTIVE: This study aimed to define the clinical course of anosmia in relation to other clinical symptoms. METHODS: 135 patients with COVID-19 were reached by phone and subsequently included in the study. Olfactory functions were evaluated using a questionnaire for assessment of self-reported olfactory function. Patients were divided into four subgroups according to the presence of olfactory symptoms and temporal relationship with the other symptoms: group1 had only olfactory complaints (isolated, sudden-onset loss of smell); group2 had sudden-onset loss of smell, followed by COVID-19 related complaints; group3 initially had COVID-19 related complaints, then gradually developed olfactory complaints; and group4 had no olfactory complaints. RESULTS: In total, 59.3% of the patients interviewed had olfactory complaints during the disease course. The olfactory dysfunction severity during COVID-19 infection was significantly higher in group1 compared to groups 2 and 3. In groups1-3, the odor scores after recovery from COVID-19 disease were significantly lower compared to the status prior to disease onset. The residual olfactory dysfunction was similar between groups1 and 2, but was more evident than group3. Mean duration for loss of smell was 7.8 ± 3.1 (2-15) days. Duration of loss of smell was longer in groups1 and 2 than in group3. Odor scores completely returned back to the pre-disease values in 41 (51.2%) patients with olfactory dysfunction. Rate of complete olfactory dysfunction recovery was higher in group3 compared to groups1 and 2. CONCLUSION: In isolated anosmia cases, anosmia is more severe, and complete recovery rates are lower compared to the patients who have other clinical symptoms. LEVEL OF EVIDENCE: Level 4.

Diagnostic utility of superb microvascular imaging in depiction of corkscrew collaterals in Buerger's disease.

PURPOSE: To evaluate the corkscrew collaterals in Buerger's disease by superb microvascular imaging (SMI) and power Doppler ultrasonography (PDU). METHODS: We evaluated with SMI and PDU 14 patients with Buerger's disease in whom corkscrew collaterals had been identified on digital subtraction angiography (DSA). Corkscrew collaterals were classified on DSA and PDU based on their size and morphology. RESULTS: A total of 17 vascular regions of collateral vessel formation were assessed. Based on DSA classification, there were three cases of type I collaterals (arterial diameter of >2 mm with large helical pattern), seven cases of type III collaterals (arterial diameter of 1-1.5 mm with small helical pattern), and seven cases of type IV collaterals (arterial diameter of <1 mm with tiny helical pattern). On PDU, all type I collaterals on DSA appeared as "large snake" images, all type III collaterals on DSA appeared as "small snake" images, and all type IV collaterals on DSA appeared as dots. SMI imaging, both in color and monochrome mode, provided superior demonstration of the continuity of the vessel of large or small "snake" images. In cases appearing as dot pattern on PDU, color SMI was able to show continuity of the flow signal as a helical pattern. DISCUSSION: SMI is a promising new Doppler imaging technique that is superior to conventional power Doppler imaging in depiction and identification of corkscrew collaterals in Buerger's disease.

Superb Microvascular Imaging in the Evaluation of Pediatric Graves Disease and Hashimoto Thyroiditis.

OBJECTIVES: We aimed to investigate the differences between spectral Doppler and Superb Microvascular Imaging (SMI; Canon Medical Systems, Tokyo, Japan) findings in children with Hashimoto thyroiditis (HT) and Graves disease (GD) compared to healthy control participants. METHODS: The study included 34 patients with GD, 37 patients with HT, and 22 healthy volunteers. All patients with HT and 11 patients with GD were euthyroid; 23 patients with GD had symptoms of hyperthyroidism and had thyrotropin values of less than 0.5 mIU/L. Thyroid volumes, mean resistive indices, and peak systolic velocities along with vascularity indices (VIs) on Superb Microvascular Imaging were measured. RESULTS: Patients with GD had a significantly higher mean thyroid volume (P < .001; right lobe, 11.80 mL; left lobe, 9.10 mL) and peak systolic velocity (right, 32.5 cm/s; left, 30 cm/s) with a lower resistive index (right, 0.48%; left, 0.48%) compared to patients with HT (right, 8.78 mL, 20 cm/s, 0.55%; left, 7.41 mL, 20 cm/s, 0.55%, respectively) and also control participants (right, 4.59 mL, 15 cm/s, 0.56%; left, 3.52 mL, 15 cm/s, 0.54%). Patients with GD had a significantly higher median VI (right, 25%; left, 26%) compared to patients with HT (right, 11%; left, 13%) and control participants (right, 8%; left, 8%). When patients with GD were categorized as euthyroid and hyperthyroid based on thyrotropin levels and clinical symptoms, both euthyroid and hyperthyroid patients with GD had significantly higher thyroid volumes compared to patients with HT (P < .001). Hyperthyroid patients with GD had higher thyroid volumes compared to euthyroid patients with GD; however, the difference failed to reach statistical significance. A significant strong positive correlation with the VI and thyrotropin receptor autoantibody levels (r = 0.696) was found. The highest area under the curve was obtained for the right lobe VI (0.885), followed by the left lobe VI (0.872), right lobe volume (0.828), and peak systolic velocity (0.810). The optimal cutoff VI value for distinguishing between HT and GD was 17.35% with sensitivity, specificity, and diagnostic accuracy of 85.3%, 78.4%, and 81.7%, respectively. CONCLUSIONS: Superb Microvascular Imaging is a new method that can detect subtle vascularity changes with higher accuracy compared to spectral Doppler parameters in distinguishing between HT and GD.

Temporal Evolution of Imaging Findings in Ossified Cephalohematoma.

BACKGROUND: Cephalohematoma is collection of blood between skull and periosteum that is confined by cranial sutures. Cephalohematomas usually resorb spontaneously within the first month of life; however, if it fails to resolve, ossified cephalohematoma may form. METHODS: Clinical archiving system and picture archiving and communication system were retrospectively reviewed for cases of birth-related cephalohematoma. Cases of ossified cephalohematomas identified on imaging were retrieved from this subset of patients. Cross-sectional imaging findings in patients with ossified cephalohematomas were evaluated for location, size of the hematoma, and contours of the inner lamella. RESULTS: Out of 115 cases of cephalohematoma, 7 cases had imaging findings consistent with ossified cephalohematoma. All ossified cephalohematomas were located parietally, with size ranging between 18 and 55 mm and the thickness of the outer rim of calcification ranging between 1.5 and 4.8 mm. The contour of inner lamella in relation to the surrounding normal cranial vault was normal in 5 cases, and inner lamella was depressed in 2 cases.Three patients had follow-up imaging available for demonstration of changes in ossified cephalohematoma. The first case was an 11 day-old boy with a cephalohematoma with no signs of calcification at the time of initial imaging. Follow-up at 2 months of age showed partial regression of hematoma cavity with marked calcification at the hematoma walls. The second case was a 3 month-old boy with ossified cephalohematoma at initial imaging. Follow-up imaging at 7 months of age showed almost total regression of hematoma cavity, and approximation of inner and outer lamella with increased thickness of the cranial vault. The third case was a 1 month-old boy with ossified cephalohematoma at initial imaging that totally resolved without residual increased bone thickness at 21-month follow-up. CONCLUSION: These 3 cases demonstrate the variability in temporal changes that may occur in ossified cephalohematomas.

Intrathoracic bifurcation of the left common carotid artery associated with rib fusion and Klippel-Feil syndrome.

Common carotid artery usually bifurcates at the superior border of thyroid cartilage, corresponding to the C3-4 junction, however bifurcation level may vary. Common carotid bifurcation may have rare variations like separate origins of left internal and external carotid arteries from aortic arch, or bifurcation of common carotid artery within thoracic cavity. Intrathoracic carotid bifurcation is a rare variation with limited number of cases reported. The occurrence of a low carotid bifurcation seems to be embryologically related to the persistence of the ductus caroticus. Additionally, intrathoracic carotid bifurcation can be accompanied by findings of Klippel-Feil syndrome. Herein, we present imaging findings of an incidentally detected intrathoracic left common carotid artery bifurcation in a pediatric patient accompanied by fusion of the cervical vertebrae and ribs.

Congenital arteriovenous fistula between descending aorta and the left innominate vein.

Thoracic aortocaval fistulae are rare entities where a direct shunt between thoracic arteries and systemic veins is seen. They can be traumatic or congenital in origin. Congenital thoracic aortocaval fistulae usually involve descending aorta and azygos, hemiazygos systems. Presenting symptoms range from continuous murmur to signs of congestive heart failure. In this case report, imaging findings of a 3-year-old girl referred for continuous murmur over the left sternal border are presented. Computed tomography angiography revealed multiple tortuous vessels along the descending aorta with a course toward the left brachiocephalic vein, and was suspicious for an aorta-venous fistula. Subsequent digital subtraction angiography for treatment planning showed a fistula originating at the level of the left 6th intercostal artery, with direct drainage into the left brachiocephalic vein without involvement of the azygos/hemiazygos system.

Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection.

PURPOSE: There are no established guidelines for treatment of Spetzler-Martin grade III-V brain arteriovenous malformations (bAVMs). The purpose of this study is to report our institutional experience in total obliteration/eradication of grade III-V bAVMs by single-stage planning of embolization combined with microsurgical resection when necessary. METHODS: All patients harboring Spetzler-Martin (S-M) grade III-V bAVMs treated with single-stage planning between January 2006 and January 2018 were retrospectively reviewed. This treatment paradigm is applicable only to surgically accessible bAVMs and does not include deep-seated bAVMs. Indications for treatment, clinical presentation, imaging characteristics, and treatment outcomes were analyzed. Outcomes were assessed based on modified Rankin Scale. RESULTS: A total of 31 patients were identified. Seventeen patients (54.8%) presented with hemorrhage, 10 (32.3%) with seizures, 3 (9.7%) with headaches, and 1 (3.2%) with progressive neurological deficit. Based on S-M grading system, 25 patients (80.6%) harbored grade III bAVM, 5 patients had grade IV bAVMs (16.1%), and 1 patient (3.2%) had a grade V bAVM. There were no treatment-related complications in 24/31 (77.4%) patients. Of the total of seven patients with complications, four patients had clinical deterioration. The long-term (> 6-month), non-disabling morbidity (mRS ≤ 2) rate was 6.5%. The long-term, disabling morbidity rate was 3.2% with a mortality of 3.2%. Complete angiographic obliteration was achieved in 30/31 (96.8%) patients. CONCLUSION: Single-stage treatment strategy can be considered as an alternative to multistage embolization prior to surgery in grade III-V bAVMs. In this study, a high rate of total obliteration with relatively low rates of permanent morbidity and mortality was achieved.

Cerebral Hydatid Cyst with Intraventricular Extension: A Case Report.

Intracranial hydatid cyst is a rare entity, comprising about 2-3% of all hydatid cysts. Similarly, intracranial hydatid cysts account for 1-2% of all intracranial lesions. Clinical symptoms are generally nonspecific and patients usually present with symptoms of increased intracranial pressure. Cerebral hydatid cysts can be either primary or secondary to systemic hydatid disease. Primary cerebral hydatid cysts are usually solitary, unilocular with an intraparenchymal location. Intraventricular extension of hydatid cysts account for a limited percentage of all cerebral hydatid cysts with limited number of cases reported. Herein, we present the imaging and surgical findings of a primary cerebral hydatid cyst that is located in frontal lobe parenchyma with partial extension into the ventricular system.

Clavicle duplication following physeal injury.

Clavicle duplication is a rare entity with limited number of cases reported. Congenital origin and trauma related mechanisms are the main hypotheses to explain this anatomical variation. In skeletally immature patient, trauma may cause physeal-metaphyseal injury in the distal clavicle rather than acromioclavicular strain. The distal epiphysis remains in continuity with acromion and has an intact periosteal sleeve. The periosteal sleeve is extremely osteogenic, and may lead to new bone formation between epiphysis and displaced metaphysis. This remodeling potential and the intact acromioclavicular joint allow the children to be followed by closed reduction. However, there can be new bone formation between epiphysis and displaced metaphysis, resulting in clavicle duplication. Herein, we present the radiographic and computed tomography findings of a post-traumatic duplication of the clavicle in a 5-year-old boy.

Amyloid Goiter: A Diagnosis to Consider in Diffuse Fatty Infiltration of the Thyroid.

An amyloid goiter is the presence of amyloid protein in the thyroid in sufficient amounts to produce enlargement of the gland, accompanied by fat deposition of varying extents. It can be seen in long-standing inflammatory disorders such as familial Mediterranean fever. Imaging findings depend on the amount of fat and amyloid deposition; however, the main imaging finding is diffuse fatty infiltration of the thyroid. Herein, the multimodality imaging features in 3 cases of amyloid goiters secondary to familial Mediterranean fever are presented.

Ex Vivo Assessment of Sentinel Lymph Nodes in Breast Cancer Using Shear Wave Elastography.

OBJECTIVES: Axillary lymph node status is one of the important prognostic factors in early-stage breast cancer. Despite the combined use of sonography, fine-needle aspiration, and sentinel lymph node (SLN) dissection, there is a gap between the potential effectiveness of those techniques and current success to determine the axillary lymph node status. The main aim of this study was to evaluate the baseline accuracy of shear wave elastography for differentiation of benign versus malignant SLNs in an ex vivo artifact-free environment. METHODS: Thirty patients with breast cancer scheduled for SLN dissection were enrolled prospectively after informed consent and Institutional Review Board approval were obtained. After dissection, lymph nodes were embedded in ultrasound gel and examined with grayscale sonography and shear wave elastography. Findings were compared to histopathologic results. RESULTS: A total of 64 SLNs obtained from the 30 patients were evaluated. Twelve of them (18.8%) were metastatic, and 52 (81.2%) were benign. The mean cortical thickness (benign versus metastatic, 1.6 versus 4.4 mm), short-axis length (4.63 versus 7.50 mm), cortical stiffness (10.7 versus 25.5 kPa), and hilar stiffness (7.5 versus 11.3 kPa) were statistically higher in metastatic lymph nodes (P ≤ .02). Area under the receiver operator characteristic curve values for these variables were 0.814, 0.768, 0.786, and 0.759, respectively. Cortical thickness was found to have the highest diagnostic performance, followed by cortical stiffness. CONCLUSIONS: Shear wave elastography can be used with grayscale sonography for evaluation of cases to decide on needle biopsy sampling. However, it cannot be used as a replacement for fine-needle aspiration or SLN dissection.

Vein of foramen caecum: imaging findings.

Vein of foramen caecum has been classically described as a vein that connects nasal mucosa to the superior sagittal sinus in classic anatomy textbooks. However, its existence is controversial in literature. Herein, we demonstrated computed tomography and contrast enhanced magnetic resonance imaging findings of a tubular vascular structure extending to nasal mucosa and superior sagittal sinus.

Impact of branch arteries on efficacy of endoluminal flow diverters: Insights from posterior communicating artery aneurysms.

BACKGROUND: Flow diverter treatment may inevitably require jailing of the branch vessels. While the patency of covered branch arteries and associated safety risks have been a topic of substantial interest, the question of whether the characteristics of branch vessels affect flow diversion's efficacy remains unanswered. In this study, we aimed to assess the impact of branch arteries on the efficacy of endoluminal flow diverters, specifically focusing on posterior communicating artery (Pcomm) aneurysms. METHODS: Following PRISMA guidelines, we systematically searched the MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane databases with predefined keywords. Studies providing data for flow diversion outcomes in Pcomm aneurysms were included. Outcomes of interest included complete and adequate aneurysm obliteration, ischemic and hemorrhagic complications, and Pcomm occlusion in the follow-up period. A random or fixed effects model was used to calculate the odds ratios (ORs) and pooled event rates with their corresponding confidence intervals (CI). RESULTS: The overall complete and adequate aneurysm occlusion rates were 72.25% (95% CI: 64.46-78.88%) and 88.37% (95% CI: 84.33-92.6), respectively. Fetal-type Pcomm aneurysms had significantly lower complete aneurysm occlusion rates than the nonfetal-type Pcomm aneurysms (OR: 0.12, 95% CI: 0.05-0.29). Overall ischemic and hemorrhagic complication rates were 2.62% (95% CI = 0.71-5.32) and 0.71% (95% CI: 0-2.24), respectively. There were no significant associations between Pcomm morphology and complications (OR: 3.61, 95% CI = 0.42-31.06 for ischemic complications and OR: 2.31, 95% CI = 0.36-14.6 for hemorrhage). Overall Pcomm occlusion rate was 32.04% (95% CI = 19.96-47.13), and the Pcomm patency was significantly lower in nonfetal-type Pcomm aneurysms (OR: 0.10, 95% CI = 0.02-0.44). CONCLUSION: Our meta-analysis suggests that flow diversion is a safe treatment option for Pcomm aneurysms, regardless of fetal-type Pcomm morphology. However, on the other hand, our findings indicate that Pcomm anatomy or the presence of jailed large branches can affect the efficacy of flow diverter treatment.

Flow Redirection Endoluminal Device (FRED) with or without Adjunctive Coiling in Treatment of Very Large and Giant Cerebral Aneurysms.

PURPOSE: Flow diverter stents are gaining wider use in the treatment of complex intracranial aneurysms; however, there are limited data on occlusion and complication rates of flow diverters in very large and giant aneurysms. This study assessed the safety and efficacy of flow redirection endoluminal device (FRED) and FRED Jr. stents in aneurysms ≥ 20 mm. METHODS: We retrospectively analyzed all aneurysms ≥ 20 mm treated with FRED/FRED Jr. between January 2010 and June 2020 from three centers. Endpoints for clinical safety were absence of major stroke, aneurysmal rupture, or death and complete or near-complete occlusion for efficacy. RESULTS: A total of 45 patients with very large (28 cases) and giant aneurysms (17 cases) were treated with FRED (41 cases), and FRED Jr. (4 cases) stents. The majority of the aneurysms (40/45, 88.9%) were in the anterior circulation. Adjunctive aneurysm coiling was performed in 21 aneurysms (46.7%). Technical complications were encountered in 4 procedures (8.9%). Ischemic and hemorrhagic complication rates were 6.7% and 8.9%, respectively. There was no case with major stroke. The mortality rate was 8.9%, and all cases were due to hemorrhagic complications from aneurysmal rupture. Median angiographic follow-up was 21.5 months (range 3-60 months). Complete occlusion was achieved in 32 aneurysms (71.1%), and near-complete occlusion in 5 cases (11.1%). CONCLUSION: The use of FRED/FRED Jr. for the treatment of aneurysms ≥ 20 mm achieved a long-term aneurysm occlusion rate and a safety profile comparable to the large series reported with other flow diverter stents.

A Comparative Olfactory MRI, DTI and fMRI Study of COVID-19 Related Anosmia and Post Viral Olfactory Dysfunction.

RATIONALE AND OBJECTIVE: To evaluate how COVID-19 anosmia imaging findings resembled and differed from postinfectious olfactory dysfunction (OD). MATERIAL AND METHODS: A total of 31 patients presenting with persistent COVID-19 related OD and 97 patients with post-infectious OD were included. Olfactory bulb MRI, DTI and olfactory fMRI findings in both groups were retrospectively assessed. RESULTS: All COVID-19 related OD cases were anosmic, 18.6% of post-infectious OD patients were hyposmic and remaining 81.4% were anosmic. Mean interval between onset of OD and imaging was 1.5 months for COVID-19 related OD and 6 months for post-infectious OD. Olfactory bulb volumes were significantly higher in COVID-19 related OD than post-infectious OD. Deformed bulb morphology and increased olfactory bulb signal intensity was seen in 58.1% and 51.6% with COVID-19 related OD; and 63.9% - 46.4% with post-infectious OD; without significant difference. Significantly higher rate of olfactory nerve clumping and higher QA values at orbitofrontal and entorhinal regions were observed in COVID-19 related OD than post-infectious OD. Absence of orbitofrontal and entorhinal activity showed no statistically significant difference between COVID-19 related OD and post-infectious OD, however trigeminosensory activity was more robust in COVID-19 related OD cases. CONCLUSION: Olfactory bulb damage may play a central role in persistent COVID-19 related anosmia. Though there is decreased olfactory bulb volume and decreased white matter tract integrity of olfactory regions in COVID-19 related anosmia, this is not as pronounced as in other post-infectious OD. Trigeminosensory activity was more robust in COVID-19 related OD. These findings may reflect better preserved central olfactory system in COVID-19 related OD compared to COVID-19 related OD.