Congenital isolated unilateral third nerve palsy in children: the diagnostic contribution of high-resolution MR imaging.

PURPOSE: To describe the neuroanatomical correlates of unilateral congenital isolated oculomotor palsy by means of high-resolution MRI. METHODS: Children with a clinical diagnosis of congenital isolated oculomotr palsy and with a high-resolution MRI acquisition targeted on the orbits and cranial nerves were selected and included in the study. An experienced pediatric neuroradiologist evaluated all the exams, assessing the integrity and morphology of extraocular muscles, oculomotor, trochlear and abducens nerves as well as optic nerves and globes. Clinical data and ophthalmologic evaluations were also collected. RESULTS: Six children (age range: 1-16 years; males: 3) were selected. All patients showed, on the affected side (left:right = 5:1), anomalies of the III nerve and extraocular muscles innervated by the pathological nerve. One patient had complete nerve agenesis, two patients showed a diffuse thinning of the nerve, from the brainstem to the orbit and 3 patients showed a distal thinning of the oculomotor nerve, starting at the level of the cavernous sinus. In all cases atrophy of corresponding muscles was noticed, but the involvement of the affected muscles varied with the nervous pattern of injury. CONCLUSIONS: High-resolution MRI represents a valuable tool for the diagnosis of III nerve anomalies in unilateral congenital IOP, showing different patterns of nerve involvement and muscular atrophy.

Glioblastoma multiforme with oculomotor nerve involvement: case report and literature review.

Gliomas involving the cranial nerves III-XIII are rare. Even rarer are glioblastomas multiforme (GBMs) with only 10 cases previously reported. Oculomotor nerve involvement was described in only 2 patients. The mechanisms proposed so far include an origin from the nerve itself or an extension within the nerve of a midbrain tumor. We report the case of a 69-year-old man who presented with an isolated left oculomotor nerve palsy. He was found to have a left temporal GBM extended to the frontal lobe. Diagnostics and intraoperative and pathological findings clearly demonstrated a massive infiltration of the cisternal portion of the left oculomotor nerve. We suppose this could be the first case of direct oculomotor nerve invasion by exophytic spread of a supratentorial GBM or by subarachnoid seeding from a temporal tumor. Less probably, it could be the first case of an oculomotor nerve GBM with a temporal lobe invasion.

Automatic oculomotor nerve identification based on data-driven fiber clustering.

The oculomotor nerve (OCN) is the main motor nerve innervating eye muscles and can be involved in multiple flammatory, compressive, or pathologies. The diffusion magnetic resonance imaging (dMRI) tractography is now widely used to describe the trajectory of the OCN. However, the complex cranial structure leads to difficulties in fiber orientation distribution (FOD) modeling, fiber tracking, and region of interest (ROI) selection. Currently, the identification of OCN relies on expert manual operation, resulting in challenges, such as the carries high clinical, time-consuming, and labor costs. Thus, we propose a method that can automatically identify OCN from dMRI tractography. First, we choose the multi-shell multi-tissue constraint spherical deconvolution (MSMT-CSD) FOD estimation model and deterministic tractography to describe the 3D trajectory of the OCN. Then, we rely on the well-established computational pipeline and anatomical expertise to create a data-driven OCN tractography atlas from 40 HCP data. We identify six clusters belonging to the OCN from the atlas, including the structures of three kinds of positional relationships (pass between, pass through, and go around) with the red nuclei and two kinds of positional relationships with medial longitudinal fasciculus. Finally, we apply the proposed OCN atlas to identify the OCN automatically from 40 new HCP subjects and two patients with brainstem cavernous malformation. In terms of spatial overlap and visualization, experiment results show that the automatically and manually identified OCN fibers are consistent. Our proposed OCN atlas provides an effective tool for identifying OCN by avoiding the traditional selection strategy of ROIs.

Malignant nerve sheath tumor of oculomotor nerve in a pediatric patient.

Malignant nerve sheath tumors are extremely rare pathologies. They tend to occur within peripheral nerves and have close association of neurofibromatosis disease. Here, we present the second case of MNST of oculomotor nerve in literature. The patient was a 2-year-old girl with left sided oculomotor nerve palsy. After resection, the patient immediately had chemotherapy and radiotherapy. One year after surgery disease progressed with extensive intracranial seedings, and she passed away.

Oculomotor nerve segment between proximal posterior and superior cerebellar arteries: an MRI study.

PURPOSE: No study has documented the oculomotor nerve (OMN) segment lying between the posterior cerebral (PCA) and superior cerebellar (SCA) arteries adjacent to the brainstem. The present study aimed to characterize it. METHODS: A total of 71 patients underwent thin-sliced, sagittal T2-weighted magnetic resonance imaging for analysis. RESULTS: The OMN segments lying between the PCA and SCA were identified in all patients. The OMN segment in relation to the PCA and SCA was classified into five types. Of them, the PCA-OMN contact type was the most frequent and found in 35.2% of 71 sides on the right and 39.4% on the left. Also, the PCA-OMN compression type was identified in 12.7% on the right and 15.5% on the left. In these types, the mean distance between the brainstem and contact/compression sites were measured 4.4 ± 2.3 mm on the right and 4.4 ± 1.6 mm on the left. In more than forty percent, the sites were located at the level of the pontomesencephalic junction. CONCLUSIONS: The OMN may be frequently in contact with the PCA near the brainstem. The site located more distal than the central-peripheral myelin junction of the OMN can attribute to a low frequency of neurovascular compression syndrome of the nerve.

Oculomotor nerve root split: incidental finding on MRI-case report and literature review.

BACKGROUND: The oculomotor nerve (OMN) innervates the pupil, ciliary body, upper eyelid, and extraocular muscles through two divisions: a superior division that innervates the levator palpebrae superioris (LPS) and superior rectus (SR), and an inferior division that supplies the medial rectus (MR), inferior rectus (IR), inferior oblique (IO), and parasympathetic fibers to the pupil and ciliary body. We present a case of complete splitting of the cisternal segment of bilateral OMNs that was discovered incidentally on magnetic resonance imaging (MRI) in a patient who had no ocular complaints. CASE REPORT: A 69-year-old patient was found to have bilateral splitting of the cisternal segments of OMNs during an MRI for trigeminal neuralgia workup. Both nerves sprang from the midbrain as distinct roots. They were symmetric on the right and minimally asymmetric on the left. On both sides, the medial root was slightly inferiorly situated. The patient had no visual problems and continued to function normally. A review of the literature for similar cases identified no such variants; however, it did identify eight examples of OMN fenestrations produced by aneurysms (AN), six of which had no OMN palsy symptoms. CONCLUSION: An anatomic variant of split bilateral OMN cisternal segments is described. The superior and inferior divisions may have different brainstem origins. Although this variant is an anatomic curiosity, it may have clinical significance and explain the various presentation of compressive OMN palsies.

The trajectory of the medial longitudinal fasciculus in the human brain: A diffusion imaging-based tractography study.

The aim of this study is to investigate the trajectory of medial longitudinal fasciculus (MLF) and explore its anatomical relationship with the oculomotor nerve using tractography technique. The MLF and oculomotor nerve were reconstructed at the same time with preset three region of interests (ROIs): one set at the area of rostral midbrain, one placed on the MLF area at the upper pons, and one placed at the cisternal part of the oculomotor nerve. This mapping protocol was tested in an HCP-1065 template, 35 health subjects from Massachusetts General Hospital (MGH), 20 healthy adults and 6 brainstem cavernous malformation (BCM) patients with generalized q-sampling imaging (GQI)-based tractography. Finally, the 200 µm brainstem template from Center for In Vivo Microscopy, Duke University (Duke CIVM), was used to validate the trajectory of reconstructed MLF. The MLF and oculomotor nerve were reconstructed in the HCP-1065 template, 35 MGH health subjects, 20 healthy adults and 6 BCM patients. The MLF was in conjunction with the ipsilateral mesencephalic part of the oculomotor nerve. The displacement of MLF was identified in all BCM patients. Decreased QA, RDI and FA were found in the MLF of lesion side, indicating axonal loss and/or edema of displaced MLF. The reconstructed MLF in Duke CIVM brainstem 200 µm template corresponded well with histological anatomy. The MLF and oculomotor nerve were visualized accurately with our protocol using GQI-based fiber tracking. This GQI-based tractography is an important tool in the reconstruction and evaluation of MLF.

Diabetic Oculomotor Nerve Palsy Displaying Enhancement of the Oculomotor Nerve in the Orbit and Cavernous Sinus on MRI.

INTRODUCTION: Imaging data were scarce on diabetic oculomotor nerve palsy (ONP). Our study explored the MRI features and their clinical implications for diabetic ONP. METHODS: Fifty-nine patients with a clinical diagnosis of diabetic ONP were recruited from our department between January 2015 and December 2019. Orbital MRI was retrospectively analyzed, and follow-up scans were obtained for 5 patients. Based on the ocular motor nerve palsy scale, the difference in the scores on the first and last hospital days was defined as the improvement score and was used to assess the treatment effects in all. RESULTS: Thirty-eight (64.41%) patients presented thickening and enhancement of the cavernous segment and inferior division of the intraorbital segment of the ipsilateral oculomotor nerve, with the cisternal segment spared in all. After complete resolution of symptoms, follow-up MRI in 5 patients revealed that the enhancement was less obvious compared with the previous images. 6 patients in the enhancement group and 4 patients in the nonenhancement group were treated with 80 mg of methylprednisolone. Significant differences were not detected in the median improvement scores between patients with and those without corticosteroid use (p = 0.240). CONCLUSION: Thickening and enhancement of the unilateral oculomotor nerve were common imaging findings in diabetic ONP, and they persisted after complete resolution of symptoms in some patients. The cavernous segment and the inferior division of the intraorbital segment were simultaneously involved, and the cisternal segment was often spared. Refraining from corticosteroids was recommended even with nerve enhancement.

Isolated Oculomotor Neuritis After Dengue Fever.

ABSTRACT: We report a rare case of isolated partial left III cranial nerve palsy due to inflammatory oculomotor neuritis after dengue fever with unique neuro-imaging findings of enhancement seen along the entire course of the oculomotor nerve.

Recurrent Third Nerve Palsy Secondary to Instrinsic Schwannoma of the Third Cranial Nerve.

ABSTRACT: A 78 year-old woman has experienced multiple episodes of transient right third nerve palsy over the course of 15 years and has undergone multiple imaging studies as well as investigations for myasthenia gravis and giant cell arteritis in search for the diagnosis. When seen after the most recent episode, MRI with contrast and Fast-Imaging Employing Steady-State Acquisition protocol revealed a subtle enlargement and enhancement of the cisternal and proximal cavernous portions of the right third cranial nerve. An empiric diagnosis of schwannoma intrinsic to third cranial nerve was made. All patients with cyclical third nerve palsies should have appropriate neuroimaging to rule out subtle structural lesions before other investigations are undertaken.

Rare neurovascular conflict between oculomotor nerve and posterior communicating artery.

Paroxysmal diplopia could be the expression of a multitude of clinical or anatomical conditions. Both ophthalmological and neurological pathologies could be responsible of this symptom. Rarely, a neurovascular conflict involving the oculomotor nerve is the etiology. We present the case of a 75-year-old man who presented for a 20-year history of transient vertical diplopia. The radiological exams demonstrated the presence of a neurovascular conflict between the right oculomotor nerve and a fetal-type posterior communicating artery. This fetal posterior communicating artery had an aberrant downward course that compressed the third cranial nerve. Few cases of neurovascular conflict interesting the third cranial nerve were described in the literature whom the responsible artery was generally the superior cerebellar artery. No case of oculomotor nerve compression by the posterior communicating artery was published. Authors have reviewed the literature and discuss the embryology of the posterior communicating artery, pathophysiology, radiological findings, and therapeutic possibility.

Damage to the inferior oblique muscle branch of the oculomotor nerve: a complication during orbital fat decompression.

PURPOSE: To present patients who suffered damage to the inferior oblique muscle branch of the oculomotor nerve during orbital fat decompression. METHODS: This study was a retrospective chart review of all patients who underwent orbital decompression surgery between April 2009 and June 2016 by the authors. RESULTS: Among 414 sides from 226 consecutive patients who underwent orbital decompression, the inferior oblique muscle branch was injured in two sides (0.5%) of two patients. Both patients showed hypotropia and incyclotropia immediately after surgery. Within 6 months of injury, ocular deviation on primary gaze had mostly resolved after conservative treatment. None of the patients underwent strabismus surgery. Postoperative computed tomographic images demonstrated that the affected branch was indistinct 3-4 mm posterior to the inferior oblique muscle. CONCLUSIONS: This report indicates that injury to the inferior oblique muscle nerve branch can occur at a point posterior to the inferior oblique muscle during orbital fat decompression; however, the resulting ocular deviation improves considerably within 6 months of injury.

Congenital Third Nerve Palsy Associated With Midbrain Hypoplasia Due to Bilateral Segmental Internal Carotid Artery Agenesis.

A 15-year-old girl, diagnosed with a partial right third nerve palsy, was found to have bilateral internal carotid artery agenesis. Neuroimaging with 3D-constructive interference in steady state scanning identified the possible etiology of the third nerve palsy as midbrain hypoplasia.

[Giant cell arteritis of the vertebrobasilar system, posterior ischemia and palsy of the third nerve. Report of one case]. / Arteritis de células gigantes en el sistema vertebrobasilar, isquemias cerebelo-occipitales y parálisis III par. Caso clínico.

Giant cell arteritis is the most common vasculitis in patients aged over 50 years. We report an 89-year-old woman with significant weight loss and persistent frontal-occipital headaches lasting two months. The neurological examination at admission identified a decrease in visual acuity of the left eye, paralysis of the third cranial nerve of the right eye and alterations of body motility without objective signs of damage of the motor or sensitive pathways. Magnetic resonance imaging showed changes of the temporal artery wall and in both vertebral arteries, as well as bilateral cerebellar and occipital ischemic lesions. The Doppler ultrasound of the temporal arteries was compatible with Giant cell arteritis. Treatment with steroids was started. While receiving oral prednisone, the patient suffered new infarcts of the posterior territory, documented with a CAT scan.

Incarceration of the inferior oblique muscle branch of the oculomotor nerve in patients with orbital floor trapdoor fracture.

PURPOSE: To examine the clinical characteristics of patients with concomitant incarceration of the inferior oblique muscle branch of the oculomotor nerve who had suffered from an orbital floor trapdoor fracture with orbital fat incarceration. METHODS: Fifty-nine patients were retrospectively reviewed. Concomitant inferior oblique muscle branch incarceration was diagnosed by inferior oblique muscle underaction on the Hess chart and a missing inferior oblique muscle branch on computed tomographic images on baseline examination. RESULTS: Eleven patients (18.6%) were diagnosed with concomitant branch incarceration. The patients with branch incarceration were all under 19 years of age, and were younger than those without branch incarceration (P = 0.026). There were no significant differences between the groups in terms of cause of injury, presence of concomitant medial wall fracture, hypoesthesia of the cheek region, or ocular and periocular complications (P > 0.050). All patients with branch incarceration underwent surgical reduction, whereas 16 of 48 patients without branch incarceration were observed without surgery (P = 0.021). Although preoperative binocular single vision field was smaller in patients with branch incarceration (P = 0.026), it improved after surgery, comparable to that of patients without branch incarceration (P = 0.079). CONCLUSIONS: Concomitant incarceration of inferior oblique muscle branch of the oculomotor nerve occurred in 18.6% of patients who had suffered from an orbital floor trapdoor fracture with orbital fat incarceration. Patients with branch incarceration were all under 19 years of age. Branch incarceration resulted in a smaller binocular single vision field, which considerably improved after surgical reduction.

The cisternal segments of the oculomotor nerve: a magnetic resonance imaging study.

PURPOSE: The cisternal segments of the oculomotor nerve (OMN), which courses through the interpeduncular and oculomotor cisterns (OMC) have not been well delineated on neuroimages. The present study aimed to explore the cisternal segments of the OMN using magnetic resonance (MR) imaging. METHODS: A total of 92 patients were enrolled in this study. A constructive interference in steady-state sequence was performed in coronal and axial sections. RESULTS: On coronal images, cisternal portions of the OMN were entirely delineated in 97 % on the right and in 98.5 % on the left. Most of the OMCs were of a round shape, with a centrally located OMN, while 9 % were ectatic with the OMN located eccentrically. In 5.3 % of cases, fetal-type posterior communicating arteries (PCoAs), which coursed adjacent to the superior surfaces of the OMNs at the oculomotor triangle (OMT), were observed. On axial images, cisternal portions of the OMN were identified in all cases. The OMN segment passing through the OMT showed medial, central, and lateral courses. The PCoAs and P2 segments of the posterior cerebral artery (PCA) were adjacent to the OMNs in 17 and 19 % of cases, respectively. CONCLUSIONS: The OMN most frequently courses in the medial part of the OMT and enters into the OMC. These findings indicate that OMN paresis can be caused by vascular compression at any site of the interpeduncular cistern and OMT.

Superior Branch Palsy of the Oculomotor Nerve Caused by Frontal Sinusitis.

Chronic rhinosinusitis is one of the most common inflammatory diseases with a significant impact on the affected patients. Orbital complications, one of the emergent complications of chronic rhinosinusitis, can be occurred in frontal sinusitis. For early diagnosis and therapy of orbital complications, proper evaluation is essential to prevent loss of vision.Recently, the authors diagnose and treat completely a 60-year-old man with isolated unilateral superior branch palsy of the oculomotor nerve caused by frontal sinusitis. Four days after draining the frontal sinusitis, the patient recovered fully from superior branch palsy of the oculomotor nerve. Frontal sinusitis can cause isolated superior branch palsy of the oculomotor nerve in patients with a history of facial trauma.

ANATOMICAL STUDY OF CRANIAL NERVE EMERGENCE AND SKULL FORAMINA IN THE HORSE USING MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY.

For accurate interpretation of magnetic resonance (MR) images of the equine brain, knowledge of the normal cross-sectional anatomy of the brain and associated structures (such as the cranial nerves) is essential. The purpose of this prospective cadaver study was to describe and compare MRI and computed tomography (CT) anatomy of cranial nerves' origins and associated skull foramina in a sample of five horses. All horses were presented for euthanasia for reasons unrelated to the head. Heads were collected posteuthanasia and T2-weighted MR images were obtained in the transverse, sagittal, and dorsal planes. Thin-slice MR sequences were also acquired using transverse 3D-CISS sequences that allowed mutliplanar reformatting. Transverse thin-slice CT images were acquired and multiplanar reformatting was used to create comparative images. Magnetic resonance imaging consistently allowed visualization of cranial nerves II, V, VII, VIII, and XII in all horses. The cranial nerves III, IV, and VI were identifiable as a group despite difficulties in identification of individual nerves. The group of cranial nerves IX, X, and XI were identified in 4/5 horses although the region where they exited the skull was identified in all cases. The course of nerves II and V could be followed on several slices and the main divisions of cranial nerve V could be distinguished in all cases. In conclusion, CT allowed clear visualization of the skull foramina and occasionally the nerves themselves, facilitating identification of the nerves for comparison with MRI images.