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.

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.

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.

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.

Evaluation of Multiparametric Shear Wave Elastography Indices in Malignant and Benign Breast Lesions.

RATIONALE AND OBJECTIVES: To evaluate the shear wave elastography indices (multiparametric SWE) of breast lesions based on patient and lesion dependent features and assess the contribution of different elastographic parameters to radiological diagnosis. MATERIALS AND METHODS: Effect of patient-dependent (age and menopausal status) and lesion-dependent (distance from the areola, quadrant location, size, depth, margin and shape) factors on SWE parameters (Vmean, Vsd, Vmax, Vmin) in benign breast lesions were assessed. Only mass lesions were included in the study. Sensitivity, specificity, PPV, NPV and cut-off values for each elastography parameter was calculated. RESULTS: A total of 496 mass lesions of breast were evaluated. 467 of the lesions were benign and 29 were malignant. There was no significant relationship among SWE indices and age, menopausal status, lesion shape and distance to the areola in benign lesions (p>0.05). SWE indices were found to be associated with lesion margin, depth from the skin, and lesion size in benign lesions (p<0.05). All BI-RADS 3 lesions that underwent biopsy were benign (n:35); 23.5% of 4a lesions were malignant (n:4/17) and all 4b-4c-5 lesions were malignant (n:25/25). The cut-off values for malignant lesions were: Vmean 3.38 m/s, Vsd 0.81, Vmax 6.87 m/s, Vmin 1.53 m/s. All SWE parameters were statistically significant in predicting malignancy on ROC analysis, Vmax was the most sensitive (96.3%) and specific (94.7%) parameter. Cut-off values for Vmax was 6.87 m/s with an accuracy rate of 94.7%, and 3.37 m/s for Vmean and 0.8 for Vsd with 92.5% accuracy. CONCLUSION: The SWE parameters to predict malignancy in breast lesions can be affected by lesion dependent features, whereas no significant effect of patient's age or menopausal status on stiffness of the lesions was observed. Vmax had the highest sensitivity for predicting malignancy.

Theoretical B3LYP Study on Electronic Structure of Contrast Agent Iopamidol.

Nonionic low-osmolar contrast agents are thought about safe for intravenous or intra-arterial administration. Iopamidol is one of the contrast agents used for diagnostic clinical computed tomography (CT) protocols last four decades years.The molecular structure of Iopamidol was calculated by the B3LYP density functional model with the LANL2DZ basis set by the Gaussian program. The natural bond orbital analysis in terms of the hybridization of atoms and the electronic structure of the title molecule have been analyzed by using the data obtained from the quantum chemical results. First-order hyperpolarizability (ßtot), the dipole moment (µ) and polarizability (α) and anisotropic polarizability (∆α) of the molecule have been reported. HOMO and LUMO energies and parameters related to energies, and dipole moment, polarizability and hyperpolarizability show minor dependences on the solvent polarity. The hardness of Iopamidol decreases with increasing solvent polarity. The stability of the Iopamidol contrast agent with the hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital analysis. In addition, thermodynamic properties were obtained in the range of 200-1000 K.

Neuroimaging findings in rheumatologic disorders.

Patients with rheumatological diseases may present with neurological manifestations of peripheral and/or central nervous system (CNS). Symptoms may be related to underlying rheumatological disease or CNS effects of immune-modulating drugs. Early diagnosis and therapy may help prevent serious complications. Magnetic resonance imaging (MRI), given its excellent soft tissue details, is the preferred imaging modality when evaluating patients with rheumatological disease and suspected CNS involvement. We present a review of the neuroimaging manifestations of various rheumatic diseases with emphasis on the imaging findings on MRI.

Machine Learning-Based Multiparametric Magnetic Resonance Imaging Radiomics for Prediction of H3K27M Mutation in Midline Gliomas.

OBJECTIVE: H3K27M mutation in gliomas has prognostic implications. Previous magnetic resonance imaging (MRI) studies have reported variable rates of tumoral enhancement, necrotic changes, and peritumoral edema in H3K27M-mutant gliomas, with no distinguishing imaging features compared with wild-type gliomas. We aimed to construct an MRI machine learning (ML)-based radiomic model to predict H3K27M mutation in midline gliomas. METHODS: A total of 109 patients from 3 academic centers were included in this study. Fifty patients had H3K27M mutation and 59 were wild-type. Conventional MRI sequences (T1-weighted, T2-weighted, T2-fluid-attenuated inversion recovery, postcontrast T1-weighted, and apparent diffusion coefficient maps) were used for feature extraction. A total of 651 radiomic features per each sequence were extracted. Patients were randomly selected with a 7:3 ratio to create training (n = 76) and test (n = 33) data sets. An extreme gradient boosting algorithm (XGBoost) was used in ML-based model development. Performance of the model was assessed by area under the receiver operating characteristic curve. RESULTS: Pediatric patients accounted for a larger proportion of the study cohort (60 pediatric [55%] vs. 49 adult [45%] patients). XGBoost with additional feature selection had an area under the receiver operating characteristic curve of 0.791 and 0.737 in the training and test data sets, respectively. The model achieved accuracy, precision (positive predictive value), recall (sensitivity), and F1 (harmonic mean of precision and recall) measures of 72.7%, 76.5%, 72.2%, and 74.3%, respectively, in the test set. CONCLUSIONS: Our multi-institutional study suggests that ML-based radiomic analysis of multiparametric MRI can be a promising noninvasive technique to predict H3K27M mutation status in midline gliomas.

Superb Microvascular Imaging in Assessment of Synovitis and Tenosynovitis in Juvenile Idiopathic Arthritis.

ABSTRACT: The aim of this study is to evaluate the diagnostic utility of superb microvascular imaging (SMI) in assessment of synovitis/tenosynovitis in juvenile idiopathic arthritis in comparison to power Doppler ultrasound. Thirty juvenile idiopathic arthritis cases with active clinical findings and ultrasound features of effusion and/or tenosynovitis were further imaged with power Doppler and SMI. For classification of synovial inflammation, a semiquantitative scale (4 points) adopted by Outcome Measures in Rheumatology was used.A total of 35 knee, 2 hip, 2 ankle, 2 wrist, 2 elbow joints, and 6 flexor hallucis longus/tibialis posterior tenosynovitis were assessed. In knee joint, power Doppler and SMI scales were the same for 23 (65.7%) joints, SMI upgraded scale from 0 to 2 in single joint (2.9%); 1 to 2 (14.3%) in 5 joints; and 2 to 3 (17.1%) in 6 joints. For other joints, power Doppler and SMI scales were the same for 5 (62.5%) joints. Superb microvascular imaging upgraded scale from 1 to 2 (25%) in 2 joints and 1 to 3 (12.5%) in a single joint. For flexor hallucis longus/tibialis posterior tenosynovitis, power Doppler and SMI scales were the same for two cases (33.3%). Superb microvascular imaging upgraded scale from 0 to 2 in two cases (33.3%); and 2 to 3 (33.3%) in 2 cases. There was no case of SMI scale downgraded compared with power Doppler scale.Superb microvascular imaging is a feasible technique in the assessment of synovial inflammation and tenosynovitis in juvenile idiopathic arthritis. Superb microvascular imaging has higher sensitivity compared with power Doppler ultrasound in depiction of increased vascularity.

Effect of Quantitative and Semi-quantitative Elastography Methods for the Management of Borderline Lesions on Ultrasonography.

BACKGROUND: Elastography (strain or shear-wave) is a method that estimates tissue stiffness. INTRODUCTION: The aim of this study is to evaluate the quantitative and semi-quantitative ultrasound elastography methods for the diagnosis of BI-RADS 4a and BI-RADS 3 lesions, which are borderline for biopsy and follow-up. MATERIALS AND METHODS: 175 consecutive women with 193 ultrasound-visible breast lesions were classified on Conventional B-mode Ultrasonography (CUS) according to the BI-RADS scoring system. Quantitative and semiquantitative values from ultrasound elastography in the form of strain Elastography Ratio (SER), shear Wave Elastography (SWE) and Shear Wave Elastography Ratio (SWER) were obtained. The lesions categorized as BI-RADS 4a and BI-RADS 3 on ultrasound were subsequently re-categorized according to the elastography values. RESULTS: Except for the 13 BI-RADS 2 lesions, the remaining 180 lesions were biopsied. Pathology showed 83 lesions to be benign and 97 to be malignant. The sensitivity and specificity of the CUS were 96.9% and 75.0%, respectively with an accuracy of 86.0%. Cut-off points calculated based on ROC curves were 56.8 kPa for SWE, 3.53 for SWER and 3.81 for SER. When we downgraded BIRADS 4a lesions based on elastography results, the specificity (CUS+SER 96.9%, CUS+SWE 91.7%, and CUS+SWER 90.6%) and the accuracy (CUS+SER 95.3%, CUS+SWE 92.7%, and CUS+SWER 92.2%) were shown to be better than CUS. When we upgraded BI-RADS 3 lesions based on elastography results, the sensitivity of combined sets of SWE (99,0%) and SWER (100,0%) was better than CUS. CONCLUSION: The rate of false-negative biopsies can be decreased with the combined use of elastography and ultrasonography.

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.

Olfactory Bulb MRI and Paranasal Sinus CT Findings in Persistent COVID-19 Anosmia.

BACKGROUND AND PURPOSE: There is limited literature consisting of case reports or series on olfactory bulb imaging in COVID-19 olfactory dysfunction. An imaging study with objective clinical correlation is needed in COVID-19 anosmia in order to better understand underlying pathogenesis. MATERIAL AND METHODS: We evaluated 23 patients with persistent COVID-19 olfactory dysfunction. Patients included in this study had a minimum 1-month duration between onset of olfactory dysfunction and evaluation. Olfactory functions were evaluated with Sniffin' Sticks Test. Paranasal sinus CTs and MRI dedicated to olfactory nerves were acquired. On MRI, quantitative measurements of olfactory bulb volumes and olfactory sulcus depth and qualitative assessment of olfactory bulb morphology, signal intensity, and olfactory nerve filia architecture were performed. RESULTS: All patients were anosmic at the time of imaging based on olfactory test results. On CT, Olfactory cleft opacification was seen in 73.9% of cases with a mid and posterior segment dominance. 43.5% of cases had below normal olfactory bulb volumes and 60.9% of cases had shallow olfactory sulci. Of all, 54.2% of cases had changes in normal inverted J shape of the bulb. 91.3% of cases had abnormality in olfactory bulb signal intensity in the forms of diffusely increased signal intensity, scattered hyperintense foci or microhemorrhages. Evident clumping of olfactory filia was seen in 34.8% of cases and thinning with scarcity of filia in 17.4%. Primary olfactory cortical signal abnormality was seen in 21.7% of cases. CONCLUSION: Our findings indicate olfactory cleft and olfactory bulb abnormalities are seen in COVID-19 anosmia. There was a relatively high percentage of olfactory bulb degeneration. Further longitudinal imaging studies could shed light on the mechanism of olfactory neuronal pathway injury in COVID-19 anosmia.

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.

Olfactory Cleft Measurements and COVID-19-Related Anosmia.

OBJECTIVE: This study aimed to investigate the differences in olfactory cleft (OC) morphology in coronavirus disease 2019 (COVID-19) anosmia compared to control subjects and postviral anosmia related to infection other than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). STUDY DESIGN: Prospective. SETTING: This study comprises 91 cases, including 24 cases with anosmia due to SARS-CoV-2, 38 patients with olfactory dysfunction (OD) due to viral infection other than SARS-CoV-2, and a control group of 29 normosmic cases. METHODS: All cases had paranasal sinus computed tomography (CT), and cases with OD had magnetic resonance imaging (MRI) dedicated to the olfactory nerve. The OC width and volumes were measured on CT, and T2-weighted signal intensity (SI), olfactory bulb volumes, and olfactory sulcus depths were assessed on MRI. RESULTS: This study showed 3 major findings: the right and left OC widths were significantly wider in anosmic patients due to SARS-CoV-2 (group 1) or OD due to non-SARS-CoV-2 viral infection (group 2) when compared to healthy controls. OC volumes were significantly higher in group 1 or 2 than in healthy controls, and T2 SI of OC area was higher in groups 1 and 2 than in healthy controls. There was no significant difference in olfactory bulb volumes and olfactory sulcus depths on MRI among groups 1 and 2. CONCLUSION: In this study, patients with COVID-19 anosmia had higher OC widths and volumes compared to control subjects. In addition, there was higher T2 SI of the olfactory bulb in COVID-19 anosmia compared to control subjects, suggesting underlying inflammatory changes. There was a significant negative correlation between these morphological findings and threshold discrimination identification scores. LEVEL OF EVIDENCE: Level 4.

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.

A new perspective on imaging of olfactory dysfunction: Does size matter?

PURPOSE: This study assesses the diagnostic utility of olfactory nerve and bulb morphologies in addition to volumetric analysis in classification of different olfactory dysfunction etiologies. METHODS: 106 patients presenting with olfactory loss and 17 control subjects were included. Based on detailed anamnesis, smell test and ear-nose-throat examination; patients were categorized into four groups as post-viral, post-traumatic, idiopathic, and obstructive olfactory dysfunction. Olfactory region was imaged with paranasal sinus CT and MRI dedicated to olfactory nerve. Olfactory bulb volume and olfactory sulcus depths were calculated on MRI. The olfactory bulb was assessed for morphology, contour lobulations and T2-signal intensity; and olfactory nerve for uniformity and clumping. RESULTS: Volumetric analysis showed decreased olfactory bulb volume in idiopathic and obstructive group compared to control subjects. Olfactory sulci were shallower in post-viral, post-traumatic, idiopathic, and obstructive group compared to the control group. In post-viral group; olfactory bulbs had lobulated contour and focal T2-hyperintense regions in 67 % of cases, and olfactory nerves had a clumped and thickened appearance in 66 % of cases. In idiopathic group, olfactory bulbs were rectangular shaped with minimally deformed contours, and olfactory nerves were thin and hard to delineate. No specific olfactory bulb or nerve pattern was identified in obstructive and post-traumatic groups, however closed olfactory cleft and siderotic frontobasal changes were helpful clues in obstructive and post-traumatic groups, respectively. CONCLUSION: In addition to olfactory cleft patency, olfactory sulcus depth and olfactory bulb volume; bulb and nerve morphologies may provide diagnostic information on different etiologies of olfactory dysfunction.

Presurgical detection of brain invasion status in meningiomas based on first-order histogram based texture analysis of contrast enhanced imaging.

OBJECTIVE: Invasion of brain parenchyma by meningioma can be a critical factor in surgical planning. The aim of this study was to determine the diagnostic utility of first-order texture parameters derived from both whole tumor and single largest slice of T1-contrast enhanced (T1-CE) images in differentiating meningiomas with and without brain invasion based on histopathology demonstration. METHODS: T1-CE images of a total of 56 cases of grade II meningiomas with brain invasion (BI) and 52 meningiomas (37 grade I and 15 grade II) with no brain invasion (NBI) were analyzed. Filtration-based first-order histogram derived texture parameters were calculated both for whole tumor volume and largest axial cross-section. Random forest models were constructed both for whole tumor volume and largest axial cross-section individually and were assessed using a 5-fold cross validation with 100 repeats. RESULTS: In detection of brain invasion, random forest model based on whole tumor segmentation had an AUC of 0.988 (95 % CI 0.976-1.00) with a cross validated value of 0.74 (95 % CI 0.45-0.96). For differentiation of grade I meningiomas from grade II meningiomas with brain invasion, the AUC was 0.999 (95 % CI 0.995-1.00) and 0.81 (95 % CI 0.61-0.99) in the training and validation cohorts, respectively. Similarly, when using only the single largest slice, the cross-validated AUC to distinguish BI versus NBI and BI versus grade I meningiomas was 0.67 (95 % CI 0.47, 0.92 and 0.78 (95 % CI 0.52, 0.95) respectively. CONCLUSION: Radiomics based feature analysis applied on routine MRI post-contrast images may be helpful to predict presence of brain invasion in meningioma, possibly with better performance when comparing BI versus grade I meningiomas.