Long-term clinical and ultrasound follow-up after transient perivascular inflammation of the carotid artery (TIPIC) syndrome: a multicenter study.

BACKGROUND: The present study aimed to describe the clinical and ultrasound (US) long-term follow-up of patients with transient perivascular inflammation of the carotid artery (TIPIC) syndrome and the risk of recurrence. METHODS: We enrolled patients with a definitive diagnosis of TIPIC syndrome who were included in a retrospective multicenter study. These patients were recontacted at least six months after the first TIPIC episode for a clinical and imaging follow-up. Each patient underwent a clinical evaluation through a tailored questionnaire as well as US imaging. RESULTS: Twenty-eight patients were enrolled with a median follow-up of 58.7 months (interquartile range = 8-121). Nineteen out of the 28 patients (67.8%) had residual pain, eight (28.6%) had experienced a clinical recurrence and 12 (42.9%) had a thickening of the carotid wall on US. No patients had neurological complication or other associated diseases. CONCLUSIONS: Patients with TIPIC syndrome have often residual pain and recurrence in about one quarter of cases but the long-term follow-up is in favor a benign self-limited pathology.Trial registration: ClinicalTrials.gov (identifier NCT03804112).

High diagnostic accuracy of T2FLAIR at 3 T in the detection of optic nerve head edema in acute optic neuritis.

OBJECTIVES: Optic nerve head edema (ONHE) detected by fundoscopy is observed in one-third of patients presenting optic neuritis (ON). While ONHE is an important semiological feature, the correlation between ONHE and optic nerve head MRI abnormalities (ONHMA), sometimes called "optic nerve head swelling," remains unknown. Our study aimed to assess the diagnostic accuracy of T2 fluid-attenuated inversion recovery (FLAIR) MRI sequence in detecting ONHE in patients with acute ON. METHODS: In the present single-center study, data were extracted from two prospective cohort studies that consecutively included adults with a first episode of acute ON treated between 2015 and 2020. Two experienced readers blinded to study data independently analyzed imaging. A senior neuroradiologist resolved any discrepancies. The primary judgment criterion of ONHMA was assessed as optic nerve head high signal intensity on gadolinium-enhanced T2FLAIR MRI sequence. Its diagnostic accuracy was evaluated with both the gold standard of ONHE on fundus photography (FP) and peripapillary retinal nerve fiber layer thickening on optic coherence tomography (OCT). RESULTS: A total of 102 patients were included, providing 110 affected and 94 unaffected optic nerves. Agreement was high between the different modalities: 92% between MRI and FP (k = 0.77, 95% CI: 0.67-0.88) and 93% between MRI and OCT (k = 0.77, 95% CI: 0.67-0.87). MRI sensitivity was 0.84 (95% CI: 0.70-0.93) and specificity was 0.94 (95% CI: 0.89-0.97) when compared with the FP. CONCLUSION: Optic nerve head high T2FLAIR signal intensity corresponds indeed to the optic nerve head edema diagnosed by the ophthalmologists. MRI is a sensitive tool for detecting ONHE in patients presenting acute ON. CLINICAL RELEVANCE STATEMENT: In patients with optic neuritis the high T2FLAIR (fluid-attenuated inversion recovery) signal intensity of the optic nerve head corresponds indeed to optic nerve head edema, which is a useful feature in optic neuritis etiological evaluation and treatment. KEY POINTS: Optic nerve head edema is a prominent clinical feature of acute optic neuritis and is usually diagnosed during dilated or non-dilated eye fundus examination. Agreement was high between magnetic resonance imaging, fundus photography, and optical coherence tomography. Optic nerve head high T2 fluid attenuation inversion recovery signal intensity is a promising detection tool for optic nerve head edema in patients presenting acute optic neuritis.

Reproducibility and accuracy of vessel wall MRI in diagnosing giant cell arteritis: a study with readers of varying expertise.

OBJECTIVE: To evaluate the reproducibility of vessel wall magnetic resonance imaging (VW-MRI) in diagnosing giant cell arteritis (GCA) among groups of radiologists with varying levels of expertise. METHODS: This institutional review board-approved retrospective single-center study recruited patients with suspected GCA between December 2014 and September 2021. Patients underwent 3 -T VW-MRI before temporal artery biopsy. Ten radiologists with varying levels of expertise, blinded to all data, evaluated several intracranial and extracranial arteries to assess GCA diagnosis. Interobserver reproducibility and diagnostic performance were evaluated. RESULTS: Fifty patients (27 women and 23 men) with a mean age of 75.9 ± 9 years were included. Thirty-one of 50 (62%) had a final diagnosis of GCA.VW-MRI had an almost perfect reproducibility among expert readers (kappa = 0.93; 95% CI 0.77-1) and substantial reproducibility among all readers, junior and non-expert senior readers (kappa = 0.7; 95% CI 0.66-0.73; kappa = 0.67 95% CI 0.59-0.74; kappa = 0.65; 95% CI 0.43-0.88 respectively) when diagnosing GCA. Substantial interobserver agreement was observed for the frontal branch of superficial temporal artery. Moderate interobserver agreement was observed for the superficial temporal artery and its parietal branch, as well as ophthalmic arteries in all groups of readers. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy varied depending on the group of readers. CONCLUSION: VW-MRI is a reproducible and accurate imaging modality for detecting GCA, even among less-experienced readers. This study advocates for the use of VW-MRI when diagnosing GCA even in less-experienced centers. CLINICAL RELEVANCE STATEMENT: VW-MRI is a reproducible and accurate imaging modality for detecting GCA, even among less-experienced readers, and it could be used as a first-line diagnostic tool for GCA in centers with limited expertise in GCA diagnosis. KEY POINTS: • Vessel wall magnetic resonance imaging (VW-MRI) is a reproducible and accurate imaging modality for detecting giant cell arteritis (GCA) in both extracranial and intracranial arteries. • The reproducibility of vessel wall magnetic resonance imaging for giant cell arteritis diagnosis was high among expert readers and moderate among less-experienced readers. • The use of vessel wall magnetic resonance imaging for giant cell arteritis diagnosis can be recommended even in centers with less-experienced readers.

Characteristics and Prognosis of Binocular Diplopia in Patients With Giant Cell Arteritis.

BACKGROUND: Giant cell arteritis (GCA) is a large vessel vasculitis associated with a risk of permanent ophthalmologic complications. Data about diplopia prognosis in GCA are scarce. This study was designed to better characterize diplopia in newly diagnosed GCA patients. METHODS: All consecutive patients diagnosed with GCA from January 2015 to April 2021 in a French tertiary ophthalmologic center were retrospectively reviewed. GCA diagnosis relied on a positive temporal artery biopsy or high-definition MRI. RESULTS: Among 111 patients diagnosed with GCA, 30 patients (27%) had diplopia. Characteristics of patients with diplopia were similar to other GCA patients. Diplopia resolved spontaneously in 6 patients (20%). Diplopia was attributed to cranial nerve palsy in 21/24 patients (88%), especially third (46%) and sixth cranial nerve (42%). Ocular ischemic lesions occurred in 11 of the 30 patients with diplopia (37%); 2 patients developed vision loss after initiation of corticosteroids. In the remaining 13 patients, diplopia resolved after treatment onset in 12 patients (92%) with a median delay of 10 days. Patients treated intravenously tended to have a quicker improvement than those treated orally, but with a similar resolution rate of diplopia at 1 month. Two patients had relapse of diplopia at 4 and 6 weeks after an initial treatment course of 24 and 18 months, respectively. CONCLUSIONS: Diplopia is a rare feature at GCA diagnosis, but should raise clinician suspicion for GCA when associated with cephalic symptoms and prompt the initiation of corticosteroids to prevent ocular ischemic complications.

Management and Outcomes of Posterior Persistent Fetal Vasculature.

PURPOSE: To describe clinical features, management, and outcomes of posterior persistent fetal vasculature (PFV) and suggest a management algorithm. DESIGN: Retrospective, consecutive case series. PARTICIPANTS: All children diagnosed with posterior PFV and treated or followed at the Rothschild Foundation Hospital in France between June 2011 and September 2021. METHODS: Retrospective analysis of the clinical characteristics of posterior PFV. We reported age, gender, presenting symptoms, intraocular pressure, and visual acuity (VA) at diagnosis. Patients were divided into 4 groups depending on the severity and involvement or not of anterior segment. We reported the vitreoretinal surgical techniques used. MAIN OUTCOME MEASURES: Anatomic results, ocular hypertension, best-corrected distance visual acuity (BCDVA), presence of postoperative adverse events, and additional surgical interventions were recorded at each follow-up visit. RESULTS: Ninety-six patients were included. The median age at diagnosis was 8 months (IQR = 12), mean 18.9 ± 30.9 months) with a mean follow-up of 27 ± 31.2 months. Although PFV is often an isolated disease, it was associated with a systemic disease in 8% of cases. There was anterior involvement in 62 (64%) of eyes. Forty-one eyes (42.7%) were microphthalmic and more frequently associated with severe PFV (53% vs. 25%; P = 0.01). Surgery was performed in 85 patients (89%). Of them, 69 (81%) had a total success, 5 (6%) had a partial success due to persistent limited peripheral retinal detachment (RD), and 11 (13%) had a failure due to persistent total RD after surgery. Postoperative adverse events occured in 38 eyes including ocular hypertension requiring eye drop medication (7.1%), secondary cell proliferation around the intraocular lens (8.2%), intravitreal hemorrhages (7.1%), and persistent tractional RD (10.6%). Second surgery was performed in 18 patients (21%). At last follow-up, VA could be measured in logarithm of the minimum angle of resolution in 43 children (45%), light perception in 21 eyes (22%), and no light perception or impossible to assess in 32 eyes (33%). CONCLUSIONS: In our case series, most patients presenting with posterior PFV received complex vitreoretinal surgery. Goals of the surgery vary and include retinal flattening, reduction of vitreoretinal traction, freeing of visual axis, and aesthetic concerns. We propose a surgical and medical management algorithm for PFV. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

A signature of structural MRI features at 3 Tesla allows an accurate characterization of orbital cavernous venous malformation.

OBJECTIVES: To differentiate OCVM from other orbital lesions using structural MRI. METHODS: This IRB-approved a historical-prospective cohort single-center analysis of a prospective cohort that included consecutive adult patients presenting with an orbital lesion undergoing a 3T MRI before surgery from December 2015 to May 2021. Two readers blinded to all data read all MRIs assessing structural MRI characteristics. A univariate analysis followed by a stepwise multivariate analysis identified structural MRI features showing the highest sensitivity and specificity when diagnosing OCVM. RESULTS: One hundred ninety-one patients with 30/191 (16%) OCVM and 161/191 (84%) other orbital lesions were included. OCVM were significantly more likely to present with a higher signal intensity than that of the cortex on T2WI: 26/29 (89.7%) versus 28/160 (17.5%), p < 0.001, or with a chemical shift artifact (CSA): 26/29 (89.7%) versus 16/155 (10.3%), p < 0.001, or to present with a single starting point of enhancement, as compared to other orbital lesions: 18/29 (62.1%) versus 4/159 (2.5%), p = 0.001. The step-wise analysis identified 2 signatures increasing performances. Signature 1 combined a higher signal intensity than that of the cortex on T2WI and a CSA. Signature 2 included these two features and the presence of a single starting point of enhancement. Sensitivity, specificity, and accuracy were 0.83, 0.94, and 0.92 for signature 1 and 0.97, 0.93, and 0.93 for signature 2, respectively. CONCLUSION: Structural MRI yields high sensitivity and specificity when diagnosing OCVM. KEY POINTS: • Structural MRI shows high sensitivity and specificity when diagnosing orbital cavernous venous malformation. • We identified two signatures combining structural MRI features which might be used easily in routine clinical practice. • The combination of higher signal intensity of the lesion as compared to the cortex on T2WI and of a chemical shift artifact yields a sensitivity and specificity of 0.83 and 0.94 for the diagnosis of orbital cavernous venous malformation, respectively.

Relevance of kappa free light chains index in patients with aquaporin-4 or myelin-oligodendrocyte-glycoprotein antibodies.

BACKGROUND: The kappa free light chains index (κ-index) is increasing in importance as a fast, easy, cost-effective, and quantitative biomarker in multiple sclerosis (MS), which can replace cerebrospinal fluid (CSF)-restricted oligoclonal bands (OCB) detection. In previous studies, controls often included mixed patients with several inflammatory central nervous system disorders. The aim of the present study was to assess the κ-index in patients with serum aquaporin-4 (AQP4)-IgG or myelin-oligodendrocyte-glycoprotein (MOG)-IgG. METHODS: We analyzed CSF/serum samples of patients with AQP4-IgG or MOG-Ig and evaluated distinct κ-index cut-offs. We described clinical and magnetic resonance imaging (MRI) features of patients with the highest κ-index values. RESULTS: In 11 patients with AQP4-IgG, median κ-index was 16.8 (range 0.2; 63) and 6/11 (54.5%) had κ-index >12. Among 42 patients with MOG-IgG, 2 had low positive MOG-IgG titers, were ultimately diagnosed with MS, and had a markedly increased κ-index (54.1 and 102.5 respectively). For the remaining 40 MOG-IgG-positive patients the median κ-index was 0.3 (range 0.1; 15.5). Some 6/40 (15%) and 1/40 (2.5%) patients had a κ-index >6 and >12, respectively. None fulfilled MRI dissemination in space and dissemination in time (DIS/DIT) criteria and the final diagnosis was MOG-IgG-associated disease (MOGAD) for these 40 patients. Four of the 40 (10%) MOG-IgG-positive patients had OCB. CONCLUSION: While a marked increase in κ-index could discriminate MS from MOGAD, a low κ-index threshold could lead to confusion between MS and MOGAD or AQP4 antibody-positive neuromyelitis optica spectrum disorder.

"National survey for preliminary evaluation of neuroradiological protocols in patients with infective endocarditis".

OBJECTIVES: The aim of this study was to identify imaging protocols in patients with infective endocarditis through a nationwide survey. METHODS: An electronic evolutionary survey was sent to interventional Neuroradiologists among neuroradiological centers, under the aegis of the Société Française de Neuroradiologie. Among 33 contacted centers, 25 completed the survey (21 universitary hospitals and 4 peripheric hospitals). RESULTS: Most of the centers (88%) used systematic imaging screening in IE patients. MRI was the first imaging method used in 66% of cases, while CT was used in 44%. When no IIA was detectable in CT-scan screening, 6 (54,54%) stopped investigations, while 9 (81,81%) continued with MRI exploration in case of hemorrhage, ischemia or enhancement. Sulcal hemorrhage on MRI was an indication of complementary DSA in 25 centers (100%). Regarding IIA characterization, 12 centers (48%) used systematic DSA, whereas for 10 centers (40%), DSA was conditioned by hemorrhage or patient status. CONCLUSION: We highlighted large variations in Neuroimaging exploration and follow-up of IE patients in real-world practices. Expert guidelines able to standardize practices are warranted to improve the management of this serious and often misdiagnosed pathology.

Early diffusion-weighted MRI at 3 Tesla detects ischemic changes of the optic nerve in anterior ischemic optic neuropathy.

OBJECTIVES: To assess the impact of timing from visual symptoms' onset to diffusion-weighted (DW) 3 T MRI completion to detect ischemic changes of the optic disc and optic nerve in AION patients. METHODS: This IRB-approved retrospective single-center study included 3 T MRI data from 126 patients with AION and 111 controls with optic neuritis treated between January 2015 and May 2020. Two radiologists blinded to all data individually analyzed imaging. A senior neuroradiologist resolved any discrepancies by consensus. The primary judgment criterion was the restricted diffusion of the optic disc and/or the optic nerve assessed subjectively on the ADC maps. ADC values were also measured. Spearman rank correlations were used to examine the relationships between timing from visual symptoms' onset to MRI completion and both the restricted diffusion and the ADC values. RESULTS: One hundred twenty-six patients (47/126 [37.3%] women and 79/126 [62.7%] men, mean age 69.1 ± 13.7 years) with AION were included. Restricted diffusion of the optic disc in AION eyes was more frequent in the early MRI group than in the late MRI group: 35/49 (71.4%) eyes versus 3/83 (3.6%) eyes, p < 0.001. ADC values of the pathological optic discs and optic nerves were lower in the early MRI group than in the late MRI group: 0.61 [0.52-0.94] × 10-3 mm2/s versus 1.28 [1.01-1.44] × 10-3 mm2/s, p < 0.001, and 0.74 [0.61-0.88] × 10-3 mm2/s versus 0.89 [0.72-1.10] × 10-3 mm2/s, p < 0.001, respectively. CONCLUSIONS: DWI MRI showed good diagnostic performance to detect AION when performed early after the onset of visual symptoms. KEY POINTS: • Restricted diffusion of the optic disc in eyes affected by AION was significantly more likely to be observed in patients who had undergone MRI within 5 days after onset of visual symptoms. • ADC values of the pathological optic discs and optic nerves were significantly lower in patients who had undergone MRI within 5 days after onset of visual symptoms of AION: 0.61 × 10-3 mm2/s versus 1.28 × 10-3 mm2/s, p < 0.001, and 0.74 × 10-3 mm2/s versus 0.89 × 10-3 mm2/s, p < 0.001, respectively. • The optimal threshold for timing from visual symptoms' onset to MRI completion to detect restricted diffusion of the optic disc and/or optic nerve was 5 days, with an AUC of 0.88 (CI95%: 0.82-0.94).

Prospective longitudinal study on prognostic factors of visual recovery and structural change after a first episode of optic neuritis.

BACKGROUND AND PURPOSE: This study was undertaken to determine the role of optical coherence tomography (OCT) in predicting the final visual and structural outcome, and to evaluate the correlation between functional eye outcome and retinal changes, in patients with a first episode of optic neuritis (ON). METHODS: In this prospective study, consecutive adult patients with acute ON underwent ophthalmological evaluation at baseline and at 1 and 12 months, including OCT measurements of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell and inner plexiform layer, and inner nuclear layer thicknesses; high- and low-contrast visual acuity; visual field assessment; and baseline brain magnetic resonance imaging. Univariate and multivariate linear regressions were used to assess predictive factors of outcome. Correlations between 12-month visual function and retinal structure were estimated by Spearman coefficients. Two groups of patients were analyzed, with or without multiple sclerosis (MS). RESULTS: Among 116 patients, 79 (68.1%) had MS, and 37 (31.9%) had ON not related to MS (including 19 idiopathic [i.e., isolated] ON, and 13 and five with myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies, respectively). We found no independent predictive factor of visual and retinal outcome. Analysis of the relationship between the visual field test (mean deviation) and pRNFL thickness demonstrated a threshold of 75.4 µm and 66.4 µm, below which the mean deviation was worse, for patients with MS (p = 0.007) and without MS (p < 0.001), respectively. CONCLUSIONS: We found that inner retinal layer measurements during the first month are not predictive of final outcome. The critical threshold of axonal integrity, below which visual function is damaged, is different between patients with and without MS.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN GIANT CELL ARTERITIS.

PURPOSE: To report the occurrence of paracentral acute middle maculopathy (PAMM) in giant cell arteritis (GCA), describe its features and outcomes, and identify risk factors associated with PAMM in patients with GCA. METHODS: Review of medical records of patients with GCA who were examined in the Rothschild Foundation Hospital. Patients were divided into three groups: GCA with PAMM (Group 1), GCA with ophthalmic involvement but without PAMM (Group 2), and GCA without ophthalmic involvement (Group 3). We analyzed the data for age, sex, medical history, laboratory testing, visual acuity, and posterior segment vascular involvement. RESULTS: Among the 96 patients who met the inclusion criteria, 52 had ophthalmic involvement, and 16 patients were included in Group 1 (GCA with PAMM). In this subgroup, the mean age was 81.6 years and was found to be older than other groups. The visual prognosis was similar between Groups 1 and 2. Of the 20 eyes with PAMM, 35% were also associated with homolateral anterior ischemic optic neuropathy. No statistical difference was found in initial symptoms, signs, and laboratory testing. CONCLUSION: Paracentral acute middle maculopathy is frequently observed lesions in ocular GCA. Patients can present with isolated findings of PAMM as the only indication of GCA. Optical coherence tomography of the macula should be routinely performed in patients with suspected GCA, specifically if they complain of visual changes, to look for signs of ischemia in the middle layers of the retina. Isolated PAMM should raise suspicion for GCA in patients at risk.

Preservation of frontal white matter tracts in ventricular surgery: favoring an anterior interhemispheric transcallosal approach vs a transcortical transfrontal transventricular approach.

Secondary to the creation of a surgical corridor and retraction, white matter tracts degenerate, causing long-term scarring with potential neurological consequences. Third and lateral ventricle tumors require surgery that may lead to cognitive impairment. Our objective is to compare the long-term consequences of a transcortical transfrontal approach and an interhemispheric transcallosal approach on corpus callosum and frontal white matter tracts degeneration. Surgical patients with ventricular tumor accessible through both approaches were included and clinico-radiological data were retrospectively analyzed. The primary endpoint was the callosotomy length at 3-month post-operative T1 MRI, corrected by the extension of the tumor and the use of neuronavigation. Secondary outcomes included perioperative criteria such as bleeding, use of retractors and duration, FLAIR hypersignal on 3-month MRI, and re-do surgeries. To assess white matter tract interruption, 3-month FLAIR hypersignal was superposed to a tractography atlas. Seventy patients were included, 57 (81%) in the transfrontal group and 13 (19%) in the interhemispheric group. There was no difference in the mean callosotomy length on 3-month MRI (12.3 mm ± 5.60 transfrontal vs 11.7 mm ± 3.92 interhemispheric, p = 0.79) on univariate and multivariate analyses. The callosotomy length was inferior by - 3.13 mm for tumors located exclusively in the third ventricle (p = 0.016), independent of the approach. Retractors were used more often in transfrontal approaches (60% vs 33%, p < 0.001). The extent of frontal FLAIR hypersignal was higher after transfrontal approach (14.1 mm vs 0.525 mm, p < 0.001), correlated to the use of retractors (p < 0.05). After the interhemispheric approach, no tract other than corpus callosum was interrupted, whereas, after the transfrontal approach, frontal arcuate fibers and projections from the thalamus were interrupted in all patients, the cingulum in 19 (33%), the superior fronto-occipital fasciculus in 15 (26%), and the superior longitudinal fasciculus in 2 (3%). Transfrontal and interhemispheric approaches to the third and lateral ventricles both lead to the same long-term damage to the corpus callosum, but the transfrontal approach interrupts several white matter tracts essential to cognitive tasks such as attention and planning, even in the non-dominant hemisphere. These results encourage all neurosurgeons to be familiar with both approaches and favor the interhemispheric approach when both can give access to the tumor with a comparable risk. Neuropsychological studies are necessary to correlate these anatomical findings to cognitive outcomes.

Use of Retinal Angiography and MRI in the Diagnosis of Giant Cell Arteritis With Early Ophthalmic Manifestations.

BACKGROUND: Giant cell arteritis (GCA) is a vasculitis often revealed by visual signs. Diagnosis is challenging and urgent. Retinal angiography (RA) and MRI allow effective diagnosis. We compared those and proposed an imaging-based approach to diagnose GCA in ophthalmological practice. METHODS: We conducted a retrospective study based on the data collected from patients suspected to have GCA on ophthalmological findings. Fluorescein (FA) and indocyanine green (ICG) RAs and MRI were performed and compared with final diagnosis. RESULTS: Among the 41 patients included, 25 were diagnosed with GCA. Sensitivities and specificities of FA and ICG were not different. MRI showed a higher sensitivity and specificity. The approach consisting in performing RA followed by MRI provided a better accuracy. CONCLUSION: Our study shows that RA can be supplemented by MRI in a specialized center to provide the most accurate diagnosis in GCA revealed by visual signs.

Transient perivascular inflammation of the carotid artery (TIPIC) syndrome.

Background: The Transient Perivascular Inflammation of the Carotid artery (TIPIC) syndrome is presumably a very rare disease characterized by a local transient inflammation of the tissue around the carotid artery. Its pathophysiology remains unknown. We performed an updated study of TIPIC syndrome cases in the setting of a multinational collaborative study. Methods: This study was conducted as an observational multinational retrospective individual patient level cohort study. Information from all known cases diagnosed with TIPIC syndrome in the literature (2005-2020) was collected after a semi-structured literature search of PubMed and Web of Science. We also collected unpublished information of patients from French, Swiss, and Italian vascular medicine or radiology departments. Results: A total of 72 patients were included and served for data analysis: 42 (58.3%) were women; the mean age was 47.9 (SD=11.4) years. Symptoms were unilateral in 92% of patients and 81.4% required pain killers. At baseline, irrespective of the imaging method used, the median thickness of the carotid lesions was 5 (Q1-Q3: 4-7; range: 2-11) mm and the median length of the lesion was 20 (Q1-Q3: 10-30; range: 3-50) mm. We found a positive linear correlation between thickness and length. At follow-up, the thickness of the carotid lesions decreased to a median of 2 (Q1-Q3: 1-3; range: 0-6) mm; the length decreased to a median 10 (Q1-Q3: 5-15; range: 0-41) mm. A linear correlation between baseline and follow-up values was observed for both thickness and length measurements. Symptoms disappeared after a median of 14 (Q1-Q3: 10-15) days. Thirteen patients experienced a recurrence after a median follow-up of 6 (Q1-Q3: 2-12) months. Conclusions: The present analysis elucidates clinical and sonographic characteristics of TIPIC syndrome, indicating the benign nature of this condition. A future international registry will study the long-term course of the disease.

Ocular MRI Findings in Patients with Severe COVID-19: A Retrospective Multicenter Observational Study.

Coronavirus disease 2019 (COVID-19) may affect various organs. This case series reports nine patients (one of nine [11%] women and eight of nine [89%] men; mean age ± standard deviation, 56 years ± 13) with globe MRI abnormalities obtained from a multicenter cohort of 129 patients presenting with severe COVID-19 from March 4, 2020, to May 1, 2020. Nine of 129 (7%) patients had one or several nodules of the posterior pole that were hyperintense at fluid-attenuated inversion-recovery imaging. All patients had nodules in the macular region, eight of nine (89%) had bilateral nodules, and two of nine (22%) had nodules outside the macular region. Screening of these patients might improve the management of potentially severe ophthalmologic manifestations of the virus. See also the editorial by Kirsch in this issue. © RSNA, 2021 Online supplemental material is available for this article.

Visual field loss and structure-function relationships in optic neuritis associated with myelin oligodendrocyte glycoprotein antibody.

BACKGROUND: A paradoxical discrepancy between severe peripapillary retinal nerve fiber layer (pRNFL) atrophy and good visual outcome had been reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-associated optic neuritis (ON). However, only visual acuity (VA) was assessed. OBJECTIVES: To study visual field (VF) outcomes of patients with MOG-IgG-associated ON and evaluate the correlation between functional eye outcome and retinal structural changes assessed by optical coherence tomography. METHODS: The records of 32 patients with MOG-IgG-associated ON who underwent ophthalmological examination at least 12 months after ON onset were reviewed. Degree of VF disability was determined by mean deviation (MD). RESULTS: At final assessment (median, 35 months), 4.2% of 48 affected eyes (AE) had VA ⩽ 0.1, 40% had abnormal MD, and among AE with final VA ⩾ 1.0, 31% had mild to moderate damage. Thinning of the inner retinal layers was significantly correlated with MD impairment. Analysis demonstrated a threshold of pRNFL thickness (50 µm), below which MD was significantly worse (mean, -2.27 dB vs -17.72 dB; p = 0.0003). ON relapse was significantly associated with poor visual outcome assessed by MD. CONCLUSION: Functional impairment measured with VF is not rare, and MD assessment better reflects actual structural damage.

Intravoxel incoherent motion (IVIM) 3 T MRI for orbital lesion characterization.

OBJECTIVES: To determine the diagnostic accuracy of MRI intravoxel incoherent motion (IVIM) when characterizing orbital lesions, which is challenging due to a wide range of locations and histologic types. METHODS: This IRB-approved prospective single-center study enrolled participants presenting with an orbital lesion undergoing a 3-T MRI prior to surgery from December 2015 to July 2019. An IVIM sequence with 15 b values ranging from 0 to 2000 s/mm2 was performed. Two neuroradiologists, blinded to clinical data, individually analyzed morphological MRIs. They drew one region of interest inside each orbital lesion, providing apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion fraction (f), and pseudodiffusion coefficient (D*) values. T test, Mann-Whitney U test, and receiver operating characteristic curve analyses were performed to discriminate between orbital lesions and to determine the diagnostic accuracy of the IVIM parameters. RESULTS: One hundred fifty-six participants (84 women and 72 men, mean age 54.4 ± 17.5 years) with 167 orbital lesions (98/167 [59%] benign lesions including 54 orbital inflammations and 69/167 [41%] malignant lesions including 32 lymphomas) were included in the study. ADC and D were significantly lower in malignant than in benign lesions: 0.8 × 10-3 mm2/s [0.45] versus 1.04 × 10-3 mm2/s [0.33], p < 0.001, and 0.75 × 10-3 mm2/s [0.40] versus 0.98 × 10-3 mm2/s [0.42], p < 0.001, respectively. D* was significantly higher in malignant lesions than in benign ones: 12.8 × 10-3 mm2/s [20.17] versus 7.52 × 10-3 mm2/s [7.57], p = 0.005. Area under curve was of 0.73, 0.74, 0.72, and 0.81 for ADC, D, D*, and a combination of D, f, and D*, respectively. CONCLUSIONS: Our study showed that IVIM might help better characterize orbital lesions. KEY POINTS: • Intravoxel incoherent motion (IVIM) helps clinicians to assess patients with orbital lesions. • Intravoxel incoherent motion (IVIM) helps clinicians to characterize orbital lymphoma versus orbital inflammation. • Management of patients becomes more appropriate.

Dixon-T2WI magnetic resonance imaging at 3 tesla outperforms conventional imaging for thyroid eye disease.

OBJECTIVES: To determine the diagnostic performances of a single Dixon-T2-weighted imaging (WI) sequence compared to a conventional protocol including T1-, T2-, and fat-suppressed T2-weighted MRI at 3 T when assessing thyroid eye disease (TED). MATERIALS AND METHODS: This IRB-approved prospective single-center study enrolled participants presenting with confirmed TED from April 2015 to October 2019. They underwent an MRI, including a conventional protocol and a Dixon-T2WI sequence. Two neuroradiologists, blinded to all data, read both datasets independently and randomly. They assessed the presence of extraocular muscle (EOM) inflammation, enlargement, fatty degeneration, or fibrosis as well as the presence of artifacts. The Wilcoxon signed-rank test was used. RESULTS: Two hundred six participants were enrolled (135/206 [66%] women, 71/206 [34%] men, age 52.3 ± 13.2 years). Dixon-T2WI was significantly more likely to detect at least one inflamed EOM as compared to the conventional set (248/412 [60%] versus 228/412 [55%] eyes; (p = 0.02). Dixon-T2WI was more sensitive and specific than the conventional set for assessing muscular inflammation (100% versus 94.7% and 71.2% versus 68.5%, respectively). Dixon-T2WI was significantly less likely to show major or minor artifacts as compared to fat-suppressed T2WI (20/412 [5%] versus 109/412 [27%] eyes, p < 0.001, and 175/412 [42%] versus 257/412 [62%] eyes, p < 0.001). Confidence was significantly higher with Dixon-T2WI than with the conventional set (2.35 versus 2.24, p = 0.003). CONCLUSION: Dixon-T2WI showed higher sensitivity and specificity and showed fewer artifacts than a conventional protocol when assessing thyroid eye disease, in addition to higher self-reported confidence. KEY POINTS: • Dixon-T2WI has better sensitivity and specificity than a conventional protocol for assessing inflamed extraocular muscles in patients with thyroid eye disease. • Dixon-T2WI shows significantly fewer artifacts than fat-suppressed T2WI. • Dixon-T2WI is faster and is associated with significantly higher self-reported reader confidence as compared to a conventional protocol when assessing inflammatory extraocular muscles.

High-resolution MRI demonstrates signal abnormalities of the 3rd cranial nerve in giant cell arteritis patients with 3rd cranial nerve impairment.

OBJECTIVE: To determine the sensitivity and specificity of high-resolution (HR) MRI for detecting signal abnormalities of cranial nerves (CN) in giant cell arteritis (GCA) patients presenting with diplopia. METHODS: This IRB-approved retrospective single-center study included GCA patients who underwent 3-T HR MRI from December 2014 to January 2020. Two radiologists, blinded to all data, individually assessed for the presence of enhancement of the 3rd, 4th, and/or 6th CN on post-contrast HR imaging and high signal intensity on HR T2-WI, for signal abnormalities of extraocular muscles and the brainstem, and for inflammatory changes of the ophthalmic and extracranial arteries. A Fisher's exact test was used to compare patients with or without diplopia. RESULTS: In total, 64 patients (42/64 (66%) women and 22/64 (34%) men, mean age 76.3 ± 8 years) were included. Of the 64 patients, 14 (21.9%) presented with diplopia. Third CN enhancement was detected in 7/8 (87.5%) patients with 3rd CN impairment, as compared to no patients with 4th or 6th CN impairment or to patients without diplopia (p < 0.001). Third CN abnormal high signal intensity on HR T2-WI was detected in 4/5 patients (80%) with 3rd CN impairment versus none of other patients (p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for detecting 3rd CN signal abnormalities were of 0.88, 1, 1, and 0.99 and 0.8, 1, 1, and 0.98 for post-contrast HR imaging and HR T2-WI, respectively. CONCLUSIONS: HR MRI had excellent diagnostic sensitivity and specificity when detecting signal abnormalities of the 3rd CN in GCA patients presenting with 3rd CN impairment. KEY POINTS: • Third cranial nerve enhancement was detected in all patients with 3rd cranial nerve impairment except for one with transient diplopia. • The "check mark sign" might be useful to identify 3rd cranial nerve signal abnormalities in the orbital apex. • No signal abnormalities of the 4th or 6th cranial nerves could be detected on high-resolution MRI.

How can we combat multicenter variability in MR radiomics? Validation of a correction procedure.

OBJECTIVE: Test a practical realignment approach to compensate the technical variability of MR radiomic features. METHODS: T1 phantom images acquired on 2 scanners, FLAIR and contrast-enhanced T1-weighted (CE-T1w) images of 18 brain tumor patients scanned on both 1.5-T and 3-T scanners, and 36 T2-weighted (T2w) images of prostate cancer patients scanned in one of two centers were investigated. The ComBat procedure was used for harmonizing radiomic features. Differences in statistical distributions in feature values between 1.5- and 3-T images were tested before and after harmonization. The prostate studies were used to determine the impact of harmonization to distinguish between Gleason grades (GGs). RESULTS: In the phantom data, 40 out of 42 radiomic feature values were significantly different between the 2 scanners before harmonization and none after. In white matter regions, the statistical distributions of features were significantly different (p < 0.05) between the 1.5- and 3-T images for 37 out of 42 features in both FLAIR and CE-T1w images. After harmonization, no statistically significant differences were observed. In brain tumors, 41 (FLAIR) or 36 (CE-T1w) out of 42 features were significantly different between the 1.5- and 3-T images without harmonization, against 1 (FLAIR) or none (CE-T1w) with harmonization. In prostate studies, 636 radiomic features were significantly different between GGs after harmonization against 461 before. The ability to distinguish between GGs using radiomic features was increased after harmonization. CONCLUSION: ComBat harmonization efficiently removes inter-center technical inconsistencies in radiomic feature values and increases the sensitivity of studies using data from several scanners. KEY POINTS: • Radiomic feature values obtained using different MR scanners or imaging protocols can be harmonized by combining off-the-shelf image standardization and feature realignment procedures. • Harmonized radiomic features enable one to pool data from different scanners and centers without a substantial loss of statistical power caused by intra- and inter-center variability. • The proposed realignment method is applicable to radiomic features from different MR sequences and tumor types and does not rely on any phantom acquisition.