F-18 Fluorodeoxyglucose PET/CT as a Diagnostic Tool in Orbital Inflammatory Disorders.

PURPOSE: To assess the usefulness of FDG-PET/CT as a potential diagnostic tool for detecting underlying systemic diseases (SD) in patients with orbital inflammatory disorders (OID). METHODS: All consecutive patients managed for new-onset OID between 2011 and 2018 in a tertiary referral center, who underwent FDG-PET/CT as part of the etiological diagnostic workup were evaluated. To quantify the incremental value of FDG-PET/CT over standard diagnostic workup, the Net Reclassification Index (NRI) and Integrated Discrimination Index (IDI) were used. RESULTS: Among the 22 patients enrolled, 11 (50%) had a positive FDG-PET/CT. After clinicobiological evaluation, FDG-PET/CT correctly reclassified 4(29%) of 14 patients with SD (p = .04) and 1(13%) of 8 with idiopathic orbital inflammation syndrome (p = .32). NRI and IDI were 0.41 ± 0.17 (p = .03) and 0.38 ± 0.08 (p < .001), respectively. FDG-PET/CT successfully detected asymptomatic lesions in all (n = 4) patients with lymphoma. CONCLUSION: FDG-PET/CT enabled accurate reclassification of more than one-quarter of patients with SD, especially extraorbital lymphomas.

Abnormal MRI findings of the orbital or visual pathways in patients with severe COVID-19: Observations from the French multicenter COVID-19 cohort.

OBJECTIVES: COVID-19 is a multisystemic disease. Ophthalmological abnormalities are relatively rare among COVID-19-infected patients. The aim of our study was to report orbital and visual pathways MRI findings in a nationwide multicenter cohort of patients with severe COVID-19. METHODS: This IRB-approved retrospective multi-center study included participants presenting with severe COVID-19, who underwent brain MRI from March 4th to May 1st 2020. Two neuroradiologists ("blinded"), blinded to all data, individually analyzed morphological MRIs focusing on the orbits and the visual pathways. A second consensus reading session was performed in the case of disagreement between both readers. Clinical and ophthalmological data were compared to MRI findings. Descriptive statistical analysis and interobserver agreement for MRI reading using non-weighted Cohen kappa statistics were performed. RESULTS: 129 participants (43 [33%] women and 86 [67%] men, mean age 63 ± 14 years) were included in the study. 17/129 (13%) patients had abnormal MRI findings of the orbit or visual pathways. 11/17 (65%) patients had a FLAIR-WI hyperintense optic disc. 6/17 (35%) patients had abnormal signal of at least one of the visual pathway structures: 6/6 (100%) of the optic nerve, 1/6 (17%) of the optic chiasm, 2/6 (33%) of the optic tract and 1/6 (17%) of the optic radiations. CONCLUSIONS: Our study showed that a substantial number of patients with severe COVID-19 presented with abnormal MRI findings of the orbit or visual pathways, which might lead to potentially severe visual impairment.

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.

MRI features of demyelinating disease associated with anti-MOG antibodies in adults.

The spectrum of Myelin Oligodendrocytes Glycoprotein (MOG) antibody disease constitutes a recently described challenging entity, referring to a relatively new spectrum of autoimmune disorders with antibodies against MOG predominantly involving the optic nerve and spinal cord. The purpose of this article is to describe MRI features of MOG-AD involvement in the optic nerves, spinal cord and the brain of adults.

IgG4-related disease in patients with idiopathic orbital inflammation syndrome: data from the French SIOI prospective cohort.

PURPOSE: To better characterize IgG4-related disease (RD) in the setting of idiopathic orbital inflammation syndrome (IOIS). METHODS: National, multicentre, prospective, observational cohort study. Among the patients consecutively included in the French multicentre SIOI cohort, we selected those who underwent orbital and/or adnexal biopsy. Clinical, morphological and pathological findings at diagnosis were blindly analysed. Serum IgG4 levels at inclusion were measured and all available biopsy specimens were immunostained for IgG4 and IgG. Biopsy samples with more than 10 IgG4-positive plasma cells per high-power field and a IgG4+/IgG+ plasma cell ratio above 40% were scored as positive. IgG4-positive patients were then screened for comprehensive diagnostic criteria for IgG4-RD. RESULTS: Of the 87 patients included, 35 had histologically documented IOIS. Thirteen patients (37%) with a mean age at onset of 27 years (range 21-78) had IgG4-positive biopsies, among which 10 patients (77%) and 3 (23%, with IgG4 serum levels >1.35 g/L) were considered as having probable and definite IgG4-RD, respectively. The latter 13 patients more frequently fulfilled histological criteria for IgG4-RD (including plasmacytic infiltrate (p = 0.006), fibrosis (p = 0.0025) and periphlebitis (p = 0.075)) than IgG4-negative patients. Storiform fibrosis was exclusively found in orbital tissues from IgG4-positive patients (n = 3, 23%). Eosinophilia associated with recurrent sinusitis or asthma was a prominent feature in patients with definite IgG4-RD. CONCLUSIONS: More than one-third of patients with biopsy-proven IOIS satisfied criteria for IgG4-RD, but only a few had a definite type.

A Puzzling Ocular Motility Disorder: Apparent Up-Gaze Fatigability in a Patient With Oculomotor Nerve Compression.

We report the case of a woman who developed right third nerve dysfunction with synkinesis and ocular neuromyotonia secondary to a compressive arterial aneurysm. Surprisingly, our examination showed a downward drift of the right eye in sustained up-gaze resulting in transient hypotropia, suggesting either fatigability of the superior rectus or contraction of the inferior rectus. We believe this ocular motility pattern is secondary to a co-contraction of the inferior rectus in up-gaze caused by synkinesis (explaining the downward drift), followed by failure of the inferior rectus to relax upon return to primary position caused by ocular neuromyotonia (explaining the hypotropia).

MRI of the Optic Nerves and Chiasm in Patients With Leber Hereditary Optic Neuropathy.

BACKGROUND: The aim of this study was to characterize brain and orbital MRI features of patients with Leber hereditary optic neuropathy (LHON), with particular attention to the optic nerves and chiasm. METHOD: We studied a patient cohort with genetically confirmed LHON followed at 2 ophthalmologic hospitals in France between 2013 and 2015. High-resolution brain and orbital MRI studies were analyzed for each patient during the first 12 months after the onset of visual loss was analyzed. RESULTS: Our study included 20 men and 8 women with a mean age of 38.3 years at diagnosis, and all had genetic mutations for LHON. Nineteen patients (67.9%) had T2 hyperintensity in the posterior portion of both optic nerves and in the optic chiasm, and enlargement of the chiasm was found in 16 patients (59.3%). No enhancement of the optic nerves or chiasm was detected. The T2 hyperintensity lesions were not associated with the time between symptom onset and obtaining MRI, the mutation type, or sex of the patient. Nonspecific T2 white matter lesions were found in MRI of 6 patients, but without the characteristics of those found in patients with multiple sclerosis. CONCLUSIONS: Involvement of the posterior portions of the optic nerves has been described previously in case reports of patients with LHON. Our results support this observation with neuroimaging performed within 1 year of onset of visual loss. Enlargement of the optic chiasm also may occur in patients with LHON. The pathophysiology of the MRI changes is not yet understood.

Isolated III cranial nerve palsies may point to primary histiocytic sarcoma.

Primary histiocytic sarcoma (HS) of the central nervous system (CNS) is a rare haematopoietic neoplasm. The inconsistent terminology and diagnostic criteria currently used for CNS HS have complicated the appreciation of the clinical aspects of the disease. The main differential diagnoses are non-Hodgkin's lymphoma, reactive histiocytic proliferation, dendritic cell neoplasm, undifferentiated carcinoma, inflammatory pseudotumour, Rosai-Dorfman disease and abscess. The true diagnosis of CNS HS requires an extensive immunophenotypic workup using specific histiocytic markers, such as CD163, with the exclusion of markers of other cell lineages. This clinicopathological case report describes an improved approach towards the differential diagnosis of CNS HS.

Abnormal inflammatory activity returns after natalizumab cessation in multiple sclerosis.

OBJECTIVE: To characterise recurrence of multiple sclerosis (MS) inflammatory activity during the year following natalizumab (NTZ) cessation. METHODS: Thirty-two patients with MS were included in a monocentric cohort study. Data were collected prospectively during and after NTZ, with serial clinical and MRI evaluations. The first relapse occurring after interrupting NTZ was the primary outcome measure. The numbers of gadolinium-enhancing lesions before, during and after NTZ treatment, were compared. RESULTS: During the year following NTZ cessation, the cumulative probability of relapses was estimated at 52.9% and an unusually high MRI inflammation was noticed. It was defined by a number of gadolinium-enhancing lesions >5 and exceeding the gadolinium lesions existing before NTZ initiation. Rebound of MS activity after NTZ cessation was characterised by association of relapses and unusual MRI inflammation. Cumulative probability of rebound was estimated at 39% and mostly occurring between 3 months and 9months after interrupting NTZ. Risk of rebound appears related with a higher annualised relapse rate and a lower Expanded Disability Status Scale score before NTZ initiation. Rebound was associated with severe recurring relapses in 9% of the patients. CONCLUSIONS: This study identifies rebound after NTZ cessation as an association of relapses and high MRI activity.

An FMRI investigation of the cortical network underlying detection and categorization abilities in hemianopic patients.

The current study aims to investigate visual scene perception and its neuro-anatomical correlates for stimuli presented in the central visual field of patients with homonymous hemianopia, and thereby to assess the effect of a right or a left occipital lesion on brain reorganization. Fourteen healthy participants, three left brain damaged (LBD) patients with right homonymous hemianopia and five right brain damaged (RBD) patients with left homonymous hemianopia performed a visual detection task (i.e. "Is there an image on the screen?") and a categorization task (i.e. "Is it an image of a highway or a city?") during a block-designed functional magnetic resonance imaging recording session. Cerebral activity analyses of the posterior areas-the occipital lobe in particular-highlighted bi-hemispheric activation during the detection task but more lateralized, left occipital lobe activation during the categorization task in healthy participants. Conversely, in patients, the same network of activity was observed in both tasks. However, LBD patients showed a predominant activation in their right hemisphere (occipital lobe and posterior temporal areas) whereas RBD patients showed a more bilateral activation (in the occipital lobes). Overall, our preliminary findings suggest a specific pattern of cerebral activation depending on the task instruction in healthy participants and cerebral reorganization of the posterior areas following brain injury in hemianopic patients which could depend upon the side of the occipital lesion.

Prognostic value of cerebrospinal fluid analysis at the time of a first demyelinating event.

BACKGROUND AND OBJECTIVE: This study aimed to assess the value of cerebrospinal fluid (CSF) findings for predicting conversion to clinically definite multiple sclerosis (CDMS). METHODS: From a database of 447 patients with a first demyelinating event, the records of 208 patients less than 51 years old who had baseline magnetic resonance imaging (MRI) and CSF examinations and a follow-up of at least 1 year were included. A multivariable Cox model was used to assess the short-term risk of CDMS according to baseline CSF findings after adjustment for prognostic factors (including brain MRI) and to provide a simple classification for predicting CDMS. RESULTS: During a median follow-up of 3.5 years, 141 (67.8%) patients converted to CDMS. In multivariate analysis, younger age (hazard ratio [HR]: 1.44 [95% CI 1.02-2.01]), spatial dissemination on brain MRI (HR: 2.07 [95% CI 1.47-2.91]) and more than 4 WBC/mm³ in CSF (HR: 1.44 [95% CI 1.03-2.02]) were independently associated with CDMS. The Cox score obtained from these three predictors enabled patients to be divided into three groups with significant increased risks of CDMS at 1, 2 and 3 years; groups were classified as high-risk (64.7%, 77.4%, 96.1%), intermediate-risk (33.3%, 51.5%, 61.5%), and low-risk (11.1%, 18.3%, 40.3%). CONCLUSIONS: Age at onset, spatial dissemination on brain MRI and CSF white blood cell count are independently associated with short-term conversion to CDMS. The three proposed risk group classifications could be a useful tool to select patients for early therapeutic intervention.

[Gliomatosis cerebri: a biopsy and autopsy case report]. / Gliomatose cérébrale diffuse: étude biopsique et autopsique d'un cas.

Gliomatosis cerebri is a rare glial neoplasm, characterized by diffuse brain infiltration with relative preservation of the underlying cytoarchitecture. Its clinical and radiologic features are not specific and its antemortem diagnosis is difficult. We report a case of gliomatosis cerebri in a 68-year-old woman presenting with gait disturbances and episodic seizures. MRI showed bilateral white matter hypersignal intensities on Flair sequences and brain biopsy revealed a poorly cellular proliferation of neoplasic glial cells strongly expressing OLIG-2, Ki-67 and occasionally GFAP, without alpha-internexin expression. The patient status worsened rapidly and she died 2 months after the initial symptoms. Postmortem brain examination confirmed gliomatosis cerebri and revealed a focal glioblastoma in the frontal cortex, with nuclear p53 expression in the highest malignant areas. Gliomatosis cerebri should be included in the differential diagnostic of diffuse brain lesions. Antemortem diagnosis, although difficult, can be assessed by IRM and careful biopsy examination. Progression to glioblastoma has been seldom reported, enhancing the controversy about the etiopathogenesis of this rare tumour.

Symptomatic paroxysmal dysarthria-ataxia in demyelinating diseases.

Paroxysmal dysarthria-ataxia syndrome (PDA) is a rare neurological disorder that can be either primary or symptomatic of acute neurological dysfunction. Episodes of symptomatic PDA are poorly documented and there are no video reports. We describe the cases of two patients with symptomatic PDA related to demyelinating diseases. Detailed studies of the patients' speech disorders showed that the dysarthria and gait disorders were of the ataxic type in both cases. Both patients had midbrain lesions at or below the level of the red nucleus, confirming that this area is critically involved in PDA. The best clinical signs for distinguishing between symptomatic and primary PDA are adult onset and short (<1 min) episodes in the former. If these signs are present, brain MRI should be used to identify a cause of symptomatic PDA.

A brainstem inflammatory lesion causing REM sleep behavior disorder and sleepwalking (parasomnia overlap disorder).

A 40-year-old woman with no prior parasomnia developed an acute inflammatory rhombencephalitis with multiple cranial nerve palsies and cerebellar ataxia, followed by myelitis 6 months later, and by an intracranial thrombophlebitis 1 month after. Between and after these episodes, she had a persistent, mild right internuclear ophtalmoplegia, a mild cerebellar ataxia, and a severe REM sleep behavior disorder (RBD) lasting for 2 years. She talked, sang and moved nightly while asleep, and injured her son (cosleeping with her) while asleep. In addition, she walked asleep nightly. During video-polysomnography, there were two arousals during slow wave sleep without abnormal behavior, while 44% of REM sleep was without chin muscle atonia with bilateral arm and leg movements. There were small hypointensities in the right pontine tegmentum and in the right dorsal medulla on T1-weighted magnetic resonance imaging, suggesting post-inflammatory lesions that persisted between acute episodes. The RBD and sleepwalking did not improve with clonazepam, but improved with melatonin 9 mg/d. The unilateral small lesion of the pontine tegmentum could be responsible for the parasomnia overlap disorder as in other rare lesional cases.

Long-term results with exophthalmos in a surgical series of 30 sphenoorbital meningiomas. Clinical article.

OBJECT: The authors analyzed the long-term results and radiological aspects of sphenoorbital meningioma (with emphasis on exophthalmos) in a series of 30 patients who underwent resection. METHODS: Data obtained in all 30 patients who underwent surgery for typical sphenoorbital meningioma at the authors' institution between June 1994 and September 2005 were analyzed retrospectively. The exophthalmos index (EI) was measured on preoperative MR images and/or CT scans and compared between the early and last follow-up examinations. All patients were women 35-74 years of age (median 51 years). Exophthalmos was the presenting symptom in 28 patients (93%), and was observed on preoperative MR images in all patients. The median duration of symptoms before surgery was 10 months (2-120 months). RESULTS: Total resection (Simpson Grade I) was not achieved in these patients because of the impossibility of resecting the dura mater in the superior orbital fissure without causing significant complications. Subtotal resection (Simpson Grade II) was obtained in 90% of patients, and in 3 patients (10%) a portion of the tumor was deliberately left in place because of extensive macroscopic infiltration of the cavernous sinus and/or extraocular muscles (Simpson Grade III). No patient died. Radiological evaluation at a median follow-up of 61 months (range 17-136 months) showed no contrast enhancement in 14 patients (47%), residual contrast enhancement without evolution in 13 (43%), and recurrence (new contrast enhancement) in 3 (10%). The EI was improved at the first radiological follow-up (median 12 months) in 27 patients (90%), and at the last radiological follow-up (median 61 months) in 28 patients (93%). In the interval between the first and final imaging follow-up, the EI improved in only 8 patients (20%), worsened in 15 patients (50%), and showed no variation in 7 patients (30%). CONCLUSIONS: Sphenoorbital meningiomas are insidious tumors with slow progression. Even when exophthalmos is not clinically evident, it is always present on preoperative MR imaging. Total resection is not possible due to superior orbital fissure invasion, but subtotal resection (Simpson Grade II) can assure long-term stability due to the nonevolutive nature of most residual tumors. Exophthalmos improves at early radiological follow-up, but may worsen again as time passes.

Case report: human brain abscess due to a tetra-acetabulate plerocercoid metacestode (Cyclophyllidea).

A 38-year-old man living near Phnom Penh (Cambodia) was admitted to a hospital in Paris in June 2001 for a single episode of a generalized grand mal seizure. This episode was preceded by a 9-month history of headaches. Magnetic resonance imaging (MRI) of the head revealed a rounded lesion immediately ahead of the left central sulcus. The resected lesion was about 20 mm in diameter. Histologic examination revealed an elongated but unsegmented metacestode at the center of the lesion. Polymerase chain reaction (PCR) analysis was inconclusive due to formalin-based histologic processing of the tissue. Morphologic analysis based on the histologic sections revealed that the metacestode was a tetra-acetabulate plerocercoid of the order Cyclophyllidea, with a distinct rostellum and pseudosegmentation of the dorsoventrally flattened hindbody. This is the first report of a tetra-acetabulate plerocercoid from a human host and the first report of any cyclophyllidean plerocercoid from the human brain. After 6 weeks, the patient was asymptomatic, neurologic examination was normal, and the brain MRI showed only surgical cavitation. The patient returned to Cambodia.