Impact of Diplopia and Ptosis From Lingering Third Nerve Palsy After Treatment of Cerebral Aneurysms.

BACKGROUND: Third nerve palsies (TNPs) may not resolve after intervention for intracranial aneurysms that have compressed the nerve. The disability related to this lingering condition has not been assessed with the support of patient self-report. METHODS: A single-institutional retrospective study of patients with TNP who had undergone interventions for intracranial aneurysms. We used residual primary-position diplopia, a narrow zone of single binocular vision, and vision-obscuring ptosis to divide TNP recovery into complete, incomplete nondisabling, and incomplete disabling outcomes based on medical record documentation and patient self-report derived from telephonic interviews. RESULTS: In a cohort of 33 patients, 13 (39%) had complete TNP recovery. There were 11 patients (33%) with lingering visual disability from diplopia or ptosis present before ophthalmic interventions. Of the 6 patients who underwent ophthalmic interventions, visual disability was relieved in only 2 patients, leaving 9 patients (27%) with lingering impairment in instrumental activities of daily living. Telephonic interviews of 23 patients (70% of the cohort) confirmed that the outcome criteria we applied were accurate in assessing visual disability in 17 patients (74%). Univariate analysis using the Fisher exact test showed that aneurysmal clipping as a treatment modality was the only clinical feature associated with a favorable TNP outcome. CONCLUSIONS: In applying a novel method of assessing disability, this study showed that more than one-quarter of patients undergoing procedures for brain aneurysms had lingering disability from third nerve palsy-associated diplopia or ptosis, despite later ophthalmic interventions. Patient self-report gleaned from telephonic interviews was valuable in largely validating the assessment method derived from medical records and in revealing differences between physician and patient estimation of disability.

A Teenage Boy With a Radiation-Induced High-Grade Astrocytoma.

ABSTRACT: A 12-year-old boy developed acute headache and vomiting. MRI brain showed a partially cystic suprasellar mass. He underwent cyst fenestration, but the cyst regrew, so he underwent transcranial subtotal resection of the mass. The pathologic diagnosis was adamantinomatous craniopharyngioma. Residual tumor was treated with proton beam radiation therapy, and panhypopituitarism was treated with hormone replacement therapy, including growth hormone. Serial brain MRI scans over several years showed no evidence of tumor recurrence. But at four years after radiation, surveillance MRI showed a new focus of nonenhancing FLAIR hyperintensity in the left basal ganglia attributed to gliosis caused by radiotherapy. Seven months later, he developed progressive right hemiparesis, expressive aphasia, and blurred vision, prompting reevaluation. MRI brain showed new enhancing and T2/FLAIR hyperintense lesions in the midbrain, basal ganglia, thalamus, anterior temporal lobe, and optic tract. The abnormal regions showed low diffusivity and relatively high regional blood flow. Stereotactic biopsy disclosed a WHO Grade 4 astrocytoma, likely radiation-induced. A germline ataxia telangiectasia mutation was found in the tumor tissue. The risk of radiation-induced pediatric brain malignancies is low but may have been increased by the mutation.

Presenting Symptoms and Imaging Features of Posterior Cerebral Artery Stroke Causing Homonymous Hemianopia.

BACKGROUND: Posterior cerebral artery (PCA) stroke is a common cause of homonymous hemianopia and other neurologic deficits associated with more proximal ischemia in the vertebrobasilar circuit. Localization of the process can be challenging unless the symptom complex is well recognized, yet early diagnosis is critical to forestall dangerous driving and repeated stroke. We undertook this study to provide additional detail about the presenting symptoms and signs and their correlation with imaging abnormalities and stroke etiology. METHODS: Retrospective study of medical records of patients presenting to a single tertiary care academic center between 2009 and 2020 with homonymous hemianopia from PCA stroke. We excerpted data on symptoms, visual and neurologic signs, incident medical procedures and diagnoses, and imaging features. We determined stroke etiology using the Causative Classification Stroke system. RESULTS: In a cohort of 85 patients, 90% of strokes occurred without preceding symptoms. But in retrospect, 10% of strokes did have warning symptoms. In 20% of patients, strokes followed within 72 hours of a medical or surgical procedure or newly identified medical condition. In the subgroups of patients whose records contained a description of visual symptoms, 87% reported the visual sensation as negative, and 66% realized that it was located in a hemifield in both eyes. Concurrent nonvisual symptoms were present in 43% of patients, consisting commonly of numbness, tingling, and new headache. Infarction located outside the visual cortex affected primarily the temporal lobe, thalamus, and cerebellum, reflecting the widespread nature of ischemia. Nonvisual clinical manifestations and arterial cutoffs on imaging were associated with thalamic infarction, but the clinical features and location of the infarction did not correlate with the etiology of the stroke. CONCLUSIONS: In this cohort, clinical localization of the stroke was aided by the fact that many patients could lateralize their visual symptoms and had nonvisual symptoms suggestive of ischemia affecting the proximal vertebrobasilar circuit. Numbness and tingling were strongly linked to concurrent thalamic infarction. Clinical features and infarct location were not associated with the etiology of the stroke.

Demographics, Risk Factors, and Etiology of Posterior Cerebral Artery Stroke Causing Homonymous Hemianopia.

BACKGROUND: Posterior cerebral artery (PCA) strokes account for up to 10% of all ischemic strokes, often presenting with homonymous hemianopia. The proportion of these strokes attributed to various etiologies varies widely in previously published studies, owing largely to differing patient populations, definitions of stroke pathogenesis, and vascular territories involved. The Causative Classification System (CCS), an automated version of the Stop Stroke Study (SSS) Trial of Org 10,172 in Acute Stroke Treatment (TOAST) system, allows for a more rigorous assignment of stroke etiology. METHODS: We excerpted clinical and imaging data on 85 patients who had PCA stroke with homonymous hemianopia examined at the University of Michigan. We compared the stroke risk factor profile of our PCA cohort with that of 135 patients with stroke in the distribution of the internal carotid artery (ICA) and middle cerebral artery (MCA) in an unpublished University of Michigan registry. We applied the CCS web-based calculator to our PCA cohort to determine stroke etiology. RESULTS: In our PCA cohort, 80.0% had at least 2 conventional stroke risk factors and 30.6% had 4 risk factors, most commonly systemic hypertension. The risk factor profile of our PCA cohort resembled that of our ICA/MCA cohort except that the mean age of our PCA cohort was more than a decade younger and had a significantly lower frequency of atrial fibrillation (AF) than our ICA/MCA cohort. In nearly half of the patients with AF in our PCA cohort, AF was diagnosed after the stroke. Among stroke etiologies in our PCA cohort, 40.0% were of undetermined cause, 30.6% were from cardioaortic embolism, 17.6% were from other determined causes, and only 11.8% were from supra-aortic large artery atherosclerosis. Strokes after endovascular or surgical interventions were prominent among other determined causes. CONCLUSIONS: Most patients in our PCA cohort had multiple conventional stroke risk factors, a finding not previously documented. Mean age at stroke onset and AF frequency were lower than in our ICA/MCA cohort, in agreement with previous studies. As some other studies have found, nearly 1/3 of strokes were attributed to cardioaortic embolism. Within that group, AF was often a poststroke diagnosis, a finding not previously highlighted. Compared with earlier studies, a relatively high portion of strokes were of undetermined etiology and of other determined etiologies, including stroke after endovascular or surgical interventions. Supra-aortic large artery atherosclerosis was a relatively uncommon explanation for stroke.

Subtle imaging signs of sigmoid sinus thrombosis in otitis media ("otitic hydrocephalus").

A 3-year-old boy developed otitis media, mastoiditis, papilledema, sixth nerve palsy, and increased intracranial pressure. The initial diagnosis was idiopathic intracranial hypertension, but doubt about that diagnosis at such a young age led to imaging reevaluation. When the abnormalities from multiple pulse sequences were aggregated with this clinical input, the correct diagnosis of otitic hydrocephalus emerged, allowing prompt implementation of appropriate treatment to avoid the risk of venous stroke.

MRI Diagnosis of Clival Cancer and Sixth Nerve Palsy.

BACKGROUND: Imaging diagnosis of clival cancer may be difficult, in part because of normal variation in marrow signal with aging. Identifying whether clival cancer has damaged the sixth cranial nerve is a further challenge because minimal clival abnormalities could impinge on the nerve, which travels very close to the clivus. METHODS: Two neuroradiologists, who were unaware of previous imaging and clinical diagnoses, reviewed MRI studies of 25 patients with cancer but no clival involvement and no sixth nerve palsy, 24 patients with clival cancer but without sixth nerve palsy, and 31 patients with clival cancer and sixth nerve palsy. The radiologists were tasked with determining whether there was clival cancer, whether there was a sixth nerve palsy and its laterality, and with indicating the pulse sequences used to make those determinations. RESULTS: Both neuroradiologists correctly identified all 25 cases with a normal clivus. In about half of those cases, they depended on finding a homogeneously bright marrow signal; in the remaining cases, they excluded cancer by determining that the clivus was not expanded and that there were no focal signal abnormalities. Both neuroradiologists correctly identified clival cancer in 54 (98%) of the 55 cases with and without sixth nerve palsy. In doing so, they relied mostly on clival expansion but also on focal signal abnormalities. Both neuroradiologists were at least 80% correct in identifying a sixth nerve palsy, but they often incorrectly identified a palsy in patients who did not have one. When there was a one-sided signal abnormality or the clivus was expanded in one direction, both neuroradiologists were accurate in identifying the side of the sixth nerve palsy. CONCLUSION: Current MRI pulse sequences allow accurate differentiation of a normal from a cancerous clivus. When the marrow signal is not homogeneously bright in adults, cancer can be diagnosed on the basis of clival expansion or focal signal abnormalities. MRI is less accurate in predicting the presence of a sixth nerve palsy. However, the side of a unilateral palsy can be predicted when the clivus is clearly expanded in one direction or there is a focal signal abnormality on one side.

Deadly Fungi: Invasive Fungal Rhinosinusitis in the Head and Neck.

Invasive fungal rhinosinusitis (IFRS) is a serious infection that is associated with high morbidity and mortality rates. The incidence of IFRS has been increasing, mainly because of the increased use of antibiotics and immunosuppressive drugs. Rhino-orbital cerebral mucormycosis has recently reemerged among patients affected by COVID-19 and has become a global concern. The detection of extrasinus involvement in its early stage contributes to improved outcomes; therefore, imaging studies are essential in establishing the degree of involvement and managing the treatment properly, especially in immunocompromised patients. The common sites of extrasinus fungal invasion are the intraorbital, cavernous sinus, and intracranial regions. Fungi spread directly to these regions along the blood vessels or nerves, causing devastating complications such as optic nerve ischemia or compression, optic neuritis or perineuritis, orbital cellulitis, cavernous sinus thrombosis, mycotic aneurysm, vasculitis, internal carotid arterial occlusion, cerebral infarction, cerebritis, and brain abscess. IFRS has a broad imaging spectrum, and familiarity with intra- and extrasinonasal imaging features, such as loss of contrast enhancement of the affected region, which indicates tissue ischemia due to angioinvasion of fungi, and the surrounding anatomy is essential for prompt diagnosis and management. The authors summarize the epidemiology, etiology, risk factors, and complications of IFRS and review the anatomy and key diagnostic imaging features of IFRS beyond the sinonasal regions. ©RSNA, 2022.

Visual Field Defect Patterns Associated With Lesions of the Retrochiasmal Visual Pathway.

BACKGROUND: Perimetry is widely used in the localization of retrochiasmal visual pathway lesions. Although macular sparing, homonymous paracentral scotomas, and quadrantanopias are regarded as features of posterior retrochiasmal visual pathway lesions, incongruous hemianopia is regarded as a hallmark of anterior lesions. Recent studies have questioned the specificity of these defect patterns. METHODS: Retrospective record review conducted in a single, academic, medical center using an electronic search engine with the terms ""homonymous hemianopia," "optic tract," "temporal lobectomy," "visual field defect," and "MRI." Patients were included if they had reliable, automated, static visual fields, high-quality reviewable MRI scans, and pertinent lesions. MRI lesions were assigned to 1 of 6 retrochiasmal visual pathway segments by the study neuroradiologist. Two study authors independently reviewed the visual fields and designated 10 different defect patterns. RESULTS: From an original cohort of 256 cases, only 83 had MRI-defined lesions that were limited to particular retrochiasmal segments and had visual field defect patterns that allegedly permitted localization to those particular segments. The 5 contralateral nerve fiber bundle defects were exclusive to optic tract tumors with rostral extension. Pie-in-the-sky defects were exclusive to Meyer loop lesions. Among 22 fields with macular sparing, 86% arose from the visual cortex or posterior optic radiations. Among 31 fields with homonymous quadrantanopias, 77% arose from Meyer loop, visual cortex, or posterior optic radiations. Among 13 fields with homonymous paracentral scotomas, 69% arose from visual cortex or posterior optic radiations. Optic tract lesions accounted for 70% of incongruous hemianopias but that pattern occurred uncommonly. CONCLUSION: In correlating discrete MRI-defined retrochiasmal lesions with visual field defect patterns identified on static perimetry, this study showed that macular sparing, homonymous paracentral scotomas, and quadrantanopias localized to the visual cortex and posterior optic radiations segments but not exclusively. It has differed from an earlier study in showing that incongruous hemianopias occur predominantly from optic tract lesions.

Accuracy of Visual Fields in Localizing MRI Lesions in Posterior Cerebral Artery Infarction.

BACKGROUND: The representation of the visual field in visual cortex was established over a century ago by correlating perimetric defects with the estimated location of war wounds. The availability of high-definition MRI offers the possibility of more precise correlation. METHODS: Homonymous hemianopias disclosed on automated visual fields (HVFs) were drawn from an electronic medical record search from 2009 to 2020 at the Michigan Medicine, a tertiary care academic medical center. The patterns of the visual field defects (VFDs) were interpreted by a consensus of 2 authors. The VFDs were correlated with the location of MRI lesions in 92 patients with posterior cerebral artery (PCA) domain ischemic strokes, as determined by the neuroradiologist author, who was masked as to the VFDs. RESULTS: Among the 77 VFDs confined to 1 hemifield, 74 (96%) correctly predicted the side of the visual cortex lesion. In 3 cases, the MRI lesion in the opposite cerebral hemisphere was not foretold. Among the 15 VFDs present in both hemifields, 5 (33.3%) overestimated the MRI lesions, which were evident in only 1 hemisphere. Among the 30 VFDs confined to 1 quadrant, 29 (97%) correctly predicted the lesioned visual cortex quadrant. However, 14 VFDs failed to predict MRI lesions present in both superior and inferior visual cortex quadrants on the same side. Those unpredicted lesions mostly had subtle or indistinct signal abnormalities or were confined to anterior visual cortex, an area that is inaccessible with the HVF test protocol used in this study. CONCLUSION: In this study of PCA ischemic stroke, VFDs limited to 1 hemifield were accurate in locating the side and quadrant of the MRI visual cortex lesions. However, the quadrantic VFDs sometimes failed to predict that the lesions involved both the superior and inferior quadrants on the same side, largely because those lesions had subtle imaging features that defied accurate radiologic assessment or were out of the reach of the visual field test protocol.

Correlation of Macular Sparing and Homonymous Paracentral Scotomas With MRI Lesions in Posterior Cerebral Artery Infarction.

BACKGROUND: The concepts of the representation of visual field in primary visual cortex are based on studies of war wounds and correlations with brain imaging in small cohorts. Because of the difficulty of judging brain lesion extent and the small number of studied patients, there is lingering controversy as to whether the central 15° of visual field are mapped onto the posterior 25% of primary visual cortex or onto a larger area. To improve the delineation of MRI lesion extent, we have studied only patients with posterior cerebral artery (PCA) ischemic strokes. METHODS: We accrued a cohort of 92 patients with PCA strokes from an electronic medical records search between 2009 and 2020 at a single tertiary care academic institution. Patients had reliable static perimetry demonstrating homonymous hemianopias and high-definition reviewable brain imaging. We divided the primary visual cortex on the MRI T1 sagittal sequence into 8 equal segments in right and left cerebral hemispheres and located lesions according to the segments they occupied. We correlated lesion locations with 3 visual field defects (VFDs): macular-sparing homonymous quadrantanopias, macular-splitting homonymous quadrantanopias, and homonymous paracentral scotomas. RESULTS: Among 25 cases with macular sparing, 13 had lesion-sparing confined to the posterior 25% of visual cortex. Among 6 cases with homonymous paracentral scotomas, 2 had lesions confined to the posterior 25% of visual cortex. Macular-splitting quadrantanopia did not occur in any patients with lesions confined to the posterior 25% of visual cortex, but did occur in 3 patients with lesions confined to the posterior 50% of visual cortex. These phenomena would not be expected if the central 15° of visual field were mapped onto a region extending beyond the posterior 25% of visual cortex. In patients with PCA strokes that involved the retrogeniculate visual pathway proximal to visual cortex, the visual cortex lesions were often less extensive than predicted by the VFDs, perhaps because of widespread damage to axons before they reached their destination in visual cortex. CONCLUSIONS: These results support the concept that the central 15° of the visual field are represented in the posterior 25% of visual cortex. Although this study contributes a larger cohort of patients with better-defined lesion borders than in past reports, its conclusions must be tempered by the variability of patient attention during visual field testing, the subjectivity in the interpretation of the defect patterns, and the difficulty in judging MRI lesion extent even on diffusion-weighted and precontrast T1 sagittal sequences.

Evaluation of Diplopia by Emergency Medicine Physicians and Consulting Neurologists.

BACKGROUND: Appropriate evaluation of diplopia requires separating serious from benign causes. If providers are not adept in this task, diagnosis of critical conditions may be delayed and unnecessary testing may result. METHODS: We studied the records of 100 consecutive patients who presented to an emergency department between 2010 and 2020 with diplopia as a prominent symptom. We rated the performance of emergency medicine physicians (EMPs) and consulting neurologists (CNs) in the examination, diagnosis, and ordering of diagnostic tests according to standards based on neuro-ophthalmologic consultation and the neuro-ophthalmologic literature. RESULTS: EMPs made no diagnosis or an incorrect diagnosis in 88 (88%) of 100 encounters. They ordered 14 unindicated and 12 incorrect studies, mostly noncontrast computed tomography scans. CNs made an incorrect diagnosis in 13 (31%) encounters. They ordered 6 unindicated and 2 incorrect studies. The total charge for unindicated and incorrect studies ordered by EMPs and CNs was $119,950. CONCLUSIONS: EMPs and CNs made frequent errors in the examination, diagnosis, and ordering of diagnostic studies, leading to inefficient care and unnecessary testing. EMPs largely delegated the evaluation of diplopia to their consultants. If such consultative support were not available, the care of diplopic patients would be delayed. CNs performed more complete examinations, but rarely enough to allow appreciation of the pattern of ocular misalignment, contributing to misdiagnoses and ordering errors. The identification of these provider errors allows for more targeted teaching in the evaluation of diplopia.

Retinal, Optic Nerve, and Cerebral Infarction in Odontogenic Lemierre Syndrome.

ABSTRACT: A 61-year-old healthy woman developed congestive orbitopathy, and bilateral retinal, optic nerve, and cerebral infarctions after removal of a chipped molar tooth. Ophthalmoscopy disclosed multiple retinal arteriolar occlusions and pallid swelling of both optic discs. Imaging revealed ipsilateral masticator and pterygoid muscle abscesses, and thrombosis of the right internal jugular vein and sigmoid sinus, both cavernous sinuses and superior ophthalmic veins, and restricted diffusion of both optic nerves and corona radiata. Blood cultures were positive for Streptococcus anginosus. Despite aggressive medical and surgical treatment, the patient remained unresponsive and presumptively blind. This case is an example of a catastrophic form of odontogenic Lemierre syndrome. Blindness, attributable to venous hypertension and vasculitis, has been rarely reported. Early recognition and treatment are critical to avoid such dire consequences.