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CT aspect of the most important foramina of the skull base. a Cribriform plate (asterisk); b optic canal (asterisk) and superior orbital fissure (arrow); c foramen rotundum (asterisk); d foramen ovale (arrow); e facial canal (arrow); f internal auditory meatus (arrow); g jugular foramen (asterisk); h hypoglossal canal (asterisk)
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Abstract The human body has 12 pairs of cranial nerves that control motor and sensory functions of the head and neck. The anatomy of cranial nerves is complex and its knowledge is crucial to detect pathological alterations in case of nervous disorders. Therefore, it is necessary to know the most frequent pathologies that may involve cranial nerves...
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... muscles" (Table 2) [5]. CT is inferior to MRI in the visualization of the cranial nerves themselves, due to its low contrast resolution. Therefore, it can be use- ful to evaluate the intraosseous segments of cranial nerves and the possible associated bony changes. Particularly, CT is optimal to study the bony foramina of the skull base (Table 3, Fig. 2) and bony traumatic lesions ...
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... along the cranial nerves. VII and VIII cranial seem to be the most affected nerves [18]. Clinically, symptoms of irritation and neural compression are present with multiple cranial neuropathies and mental status changes, secondary to meningeal irritation and hydrocephalus. The nerve may enhance on post-gadolinium sequences and appear enlarged (Fig. 22). Neural enhancement can be very subtle and bet- ter demonstrated on post-Gadolinium fluid-attenuated in- version recovery (FLAIR) sequences ...
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... show marked and homogeneous enhancement with rare central nonehan- cing areas, corresponding to necrosis or calcification phe- nomena. In up to 72% of cases, a "dural tail" is evident, as enhancement of the neighboring dura mater. Possibly associated bony changes can be osteolysis, hyperostosis, and enlargement of the adjacent foramina [21] (Fig. 23). Meningioma may also affect the optic nerve, appearing as homogeneous enhancing lesion around the optic nerve, with intermediate T1 and T2 signal ...
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... term optic neuritis (ON) usually refers to inflamma- tory process that involve optic nerve. Clinically, it pre- sents with painful eye movements and visual loss. On MRI, the nerve appears swollen and hyperintense on T2-weighted sequences, with contrast enhancement best seen on fat-suppressed T1-weighted sequences [8] (Fig. 24). ON may be observed in autoimmune (for ex- ample multiple sclerosis and neuromyelitis optica spectrum disorders) and systemic diseases (sarcoidosis, lupus erythematosus, Wegener disease, Sicca syndrome, Behcet disease) [23]. Particularly, in neuromyelitis optica spectrum disorder (NMOSD), nerve involvement may be bilateral and more ...
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... Tolosa-Hunt consists in a granulomatous inflammation of the lateral wall of the cavernous sinus or superior orbital fissure. Imaging techniques can show an infiltrative soft tissue mass within the cavernous sinus that appears enlarged. The tissue is hypo-isointense on T2-weighted sequences, with avid contrast enhancement on post-gadolinium images (Fig. 25). Differential diagnosis may include lym- phoma, sarcoidosis, metastatic disease, meningioma, infection, granulomatous pachimeningitis, Meckel's cave schwannoma, aneurysm, and pituitary macroadenoma [25]. Clinical findings may overestimate this condition and MRI is critical to exclude other similar conditions, allowing for precise ...
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... does not require imaging studies. How- ever, MRI may be useful to exclude other lesions respon- sible of atypical Bell's palsy (gradual-onset palsy, failure to improve with time) or recurrent palsy [26]. On MRI, the fa- cial nerve shows increased enhancement on post-contrast sequences that may involve one or more segments, with- out nodularity (Fig. 26). Enhancement of distal intrameatal and labyrinthine segments is typical [26]. On T2-weighted sequences, the nerve may be hyperintense. In case of irregular or nodular enhancement, other causes of path- ology (such as perineural spread of tumor) should be eval- uated. Bilateral Bell's palsy is unusual, often associated with HIV or other ...
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... but also allergic and autoimmune causes are described. Inflammation of the vestibular nerve may be complicated by demyelination, with loss of function, not always reversible [29]. MRI shows hyperintensity of the cisternal tract of the vestibular nerve on T2-weighted and FLAIR sequences [30] with enhancement on post-gadolinium images [31] (Fig. 27). Acute labyrinthitis is similar to vestibular neuritis with associated hearing loss and tinnitus ...
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... is typically caused by Hae- mophilus Influenzae, Streptococcus pneumoniae, and Neis- seria Meningitidis. Imaging is often normal, although MRI post-contrast sequences can demonstrate leptomeningeal enhancement [5]. Intracranial Tuberculosis, typically in pediatric population, can manifest as leptomeningitis with involvement of cranial nerves (Fig. 28). Cryptococcus neo- formans is associated with the Cryptococcal meningitis, characterized by optic neuropathy. Necrosis of the optic nerve and chiasm by cryptococcal organism have been de- scribed. Rhinocerebral mucormycosis is fungal infection in immunocompromised patients, with sinonasal disease that may progress to the orbit and ...
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... CT is the imaging modality of choice to detect skull base fractures and foraminal in- volvement. MRI may be useful to demonstrate intraneural edema or hemorrhage, especially on T2*- weighted sequences. Olfactory nerve may be involved in the closed injury of basal frontal lobe, with or without association of cribriform plate fracture (Fig. 29). Optic and oculomotor nerves may be affected in the orbital and optic canal fractures. Lesions of the abducens nerve are reported in the fracture of the clivus and petrous apex. Injuries of the facial nerve are associated to tem- poral bone fractures, that are classified as transverse or longitudinal based on their relationship to the ...
Citations
... Magnetic resonance imaging (MRI) is commonly employed for assessing cranial neuropathies. Given that neoplastic and in ammatory lesions are constantly considered in the diagnosis, contrast-enhanced studies are preferred because they visualize nerve enhancement attributed to leakage, forcing spillage, and accumulation of contrast material surrounded by CSF [2] . ...
Background: This study aims to examine the clinical value of 1-hour delayed gadolinium-DTPA-enhanced3D T1 SPACE MRI in Bell's palsy.
Methods: Patients diagnosed with Bell’s palsy between January 2021 and January 2023 were retrospectively selected. Both routine and 1-hour delayed contrast-enhanced MRI were analyzed retrospectively. Signal intensity ratios of the facial nerve to that of the adenohypophysis were calculated.
Results: The affected side's signal intensity ratio was higher than the unaffected side in the labyrinthian and geniculate ganglion segments on both routine and 1-hour delayed contrast-enhanced MRI. Additionally, the signal intensity ratio of the affected side labyrinthian and geniculate ganglion segments in 1-hour delayed contrast-enhance MRI was higher than routine contrast-enhance MRI.
Conclusions: A contrast-enhance MRI of Bell’s palsy is functional for detecting inflammatory lesions. Delayed contrast-enhance MRI can indicate a higher distinction in the affected facial nerve.
... Then, it divides into the zygomaticofacial and zygomaticotemporal nerves, providing sensory innervation to the upper and lower eyelids, conjunctiva, hard and soft palates, upper dental arch, and the rostral and maxillary aspect of the face. The mandibular branch, or V 3 , emerging to the orbit through the foramen ovale, provides sensory innervation to the buccal mucosa, mandibular teeth, and the skin below the mouth and motor innervation to the masseter, the temporalis, the pterygoids, the anterior belly of the digastric, and the mylohyoid muscles [13][14][15][16]. ...
The trigeminal nerve is responsible for innervating the periorbita. Ultrasound-guided trigeminal block is employed in humans for trigeminal neuralgia or periorbital surgery. There are no studies evaluating this block in dogs. This study aims to evaluate and compare two approaches (coronoid and temporal) of the trigeminal nerve block. We hypothesised superior staining with the coronoid approach. Thirteen dog heads were used. After a preliminary anatomical study, two ultrasound-guided injections per head (right and left, coronoid and temporal approach, randomly assigned), with an injectate volume of 0.15 mL cm−1 of cranial length, were performed (iodinated contrast and tissue dye mixture). The ultrasound probe was placed over the temporal region, visualising the pterygopalatine fossa. For the temporal approach, the needle was advanced from the medial aspect of the temporal region in a dorsoventral direction. For the coronoid approach, it was advanced ventral to the zygomatic arch in a lateromedial direction. CT scans and dissections were conducted to assess and compare the position of the needle, the spread of the injectate, and nerve staining. No significant differences were found. Both approaches demonstrated the effective interfascial distribution of the injectate, with some minimal intracranial spread. Although the coronoid approach did not yield superior staining as hypothesised, it presents a viable alternative to the temporal approach. Studies in live animals are warranted to evaluate clinical efficacy and safety.
... The maxillary branch, or V2, exits the skull through the rostral alar foramen, passing through the peribulbar space, further divides into the zygomaticofacial and zygomaticotemporal nerves, providing sensory innervation to the upper and lower eyelids, conjunctiva, hard and soft palates, upper dental arch and the rostral and maxillary aspect of the face. The mandibular branch, or V3, emerging to the orbit through the foramen ovale, providing sensory innervation to the buccal mucosa, mandibular teeth, and the skin below the mouth and motor innervation to the masseter, the temporalis, the pterygoids, the anterior belly of the digastric and the mylohyoid muscles [13][14][15][16]. ...
The trigeminal nerve is responsible for innervating the periorbita. Ultrasound-guided trigeminal block is employed in humans for trigeminal neuralgia or periorbital surgery. There are no studies evaluating this block in dogs. This study aims to evaluate and compare two approaches (coronoid and temporal) of the trigeminal nerve block. We hypothesized superior staining with the coronoid approach. Thirteen dog heads were used. After a preliminary anatomical study, two ultrasound-guided injections per head (right and left, coronoid and temporal approach, randomly assigned), with an injectate volume of 0.15 mL cm-1 of cranial length were performed (iodate contrast and tissue dye mixture). The ultrasound probe was placed over the temporal region, visualizing the pterygopalatine fossa. For the temporal approach, the needle was advanced from the medial aspect of the temporal region in a dorsoventral direction. For the coronoid approach, it was advanced ventral to the zygomatic arch in a lateromedial direction. CT scans and dissections were conducted to assess and compare the position of the needle, spread of injectate, and nerve staining. No significant differences were found. Both approaches demonstrated effective interfascial distribution of injectate, with some minimal intracranial spread. Although the coronoid approach did not yield superior staining as hypothesized, it presents a viable alternative to the temporal approach. Studies in live animals are warranted to evaluate clinical efficacy and safety.
... However, the initial symptoms in our case included gaze asymmetry, unsteady gait, occasional choking, aggravated headache, and facial palsy; no hearing impairment was observed. These symptoms may have resulted from the cerebellum or brain stem or from cranial nerve compression by the large (5.7-cm) tumor [4,14,15]. In a study involving 6225 adult patients [16], the average size of presenting VSs was 1.6 cm; therefore, the tumor size in our case was considerably larger than most pediatric and adult VS cases [5][6][7][9][10][11][12][13]. ...
Sporadic vestibular schwannomas (VSs) are rare in children. When occurred in the pediatric population, they usually appear bilaterally and are related to neurofibromatosis type 2 (NF2). The current study reports a 4-year-old boy without family history of VS or NF2 who presented with a large (5.7-cm) VS involving the right cerebellopontine angle and internal auditory canal. Through seven-staged surgical interventions and two stereotactic γ‑knife radiosurgery, the disease was stabilized. At 2-year follow-up, the child had right ear hearing loss, grade IV facial palsy, and normal motor function and gait. No definite evidence of gene mutation regarding NF2 can be identified after sequence analysis and deletion/duplication testing. This case highlights the significance of considering the possibility of sporadic VSs, even in very young children. It emphasizes the importance of not overlooking initial symptoms, as they may indicate the presence of a large tumor and could potentially result in delayed diagnosis.
... But the exact distinction between the type of CNP and the corresponding CT finding could not be established from our study. CT scans have been useful for assessing the fracture extension and intraosseous cranial nerve segment [23]. We could not identify any literature that compares the type of CNP with the CT findings and the correlation between the two. ...
Background
Cranial nerve palsy (CNP) is a common complication of traumatic brain injury (TBI). Despite a high incidence of TBI in Nepal (382 per 100,000), literature on the specific management and outcome of CNP is lacking. This study aimed to examine the outcomes of TBI patients involving single versus multiple CNP.
Methods
A retrospective chart review of 170 consecutive TBI patients admitted to the tertiary neurosurgical center in Nepal between April 2020 and April 2022 was conducted. Demographic, clinical, and etiological characteristics; imaging findings; and management strategies were recorded, compared, and analyzed using descriptive statistics. The Glasgow Outcome Scale Extended (GOSE) was used to measure the outcomes in two groups of patients (single and multiple CNP) at 3 months.
Results
Out of 250 eligible patients, 80 were excluded and CNP was noted in 29 (17.1%) of the remaining 170. The median age was 34.9 years, and falls (60.6%) were the most common cause of trauma. TBI severity was categorized based on GCS: mild (82.4%), moderate (15.9%), and severe (1.8%). Cranial nerve involvement was seen in 29 (17.05%) patients: single cranial nerve involvement in 26 (89.65%) and multiple nerve involvement in 3 (10.34%). The most common isolated cranial nerve involved was the oculomotor nerve (37.9%). CT findings revealed a maximum of skull fractures with no significant association between CNP and CT findings.
Conclusions
CNP is a common consequence of TBI with the most common etiology being falls followed by RTA. Single CNP was more common than multiple CNP with no significant difference in the outcome in the 3-month GOSE score. Further research is needed to determine the burden of traumatic CNP and establish specific management guidelines for different types of CNP.
... The optic nerve is approximately 5 cm in length and comprised of four segments: intraocular (1 mm), intraorbital (2.5-3 cm), intracanalicular, and prechiasmatic [22,23]. As an extension of the central nervous system, the optic nerve is surround by all three meningeal layers (dura, arachnoid, and pia mater) with an outer periosteal layer, the periorbita, which is continuous with the intracranial periosteal dura [22]. ...
... The optic nerve is approximately 5 cm in length and comprised of four segments: intraocular (1 mm), intraorbital (2.5-3 cm), intracanalicular, and prechiasmatic [22,23]. As an extension of the central nervous system, the optic nerve is surround by all three meningeal layers (dura, arachnoid, and pia mater) with an outer periosteal layer, the periorbita, which is continuous with the intracranial periosteal dura [22]. The average length of the bony orbit is 4 cm from base to orbital apex, separated by approximately 2.5 cm between the medial orbital wall from one side to the other. ...
Advances in technology, instrumentation, and reconstruction have paved the way for extended endoscopic approaches to skull base tumors. In the sagittal plane, the endonasal approach may safely access pathologies from the frontal sinus to the craniocervical junction in the sagittal plane, the petrous apex in the coronal plane, and extend posteriorly to the clivus and posterior cranial fossa. This review article describes these modular extended endoscopic approaches, along with crucial anatomic considerations, illustrative cases, and practical operative pearls.
... Secondly, LAVA-Flex proves particularly adept at displaying cranial nerves-an essential consideration for NPC staging. MRI is widely regarded as the gold standard for visualizing cranial nerves (29). Given that most cranial nerves exhibit slender structures with tortuous paths, conventional T1WI-IDEAL sequences often struggle to fully capture their complexity due to thick and spaced layers. ...
Introduction
Magnetic resonance imaging (MRI) staging scans are critical for the diagnosis and treatment of patients with nasopharyngeal cancer (NPC). We aimed to evaluate the application value of LAVA-Flex and T1WI-IDEAL sequences in MRI staging scans.
Methods
Eighty-four newly diagnosed NPC patients underwent both LAVA-Flex and T1WI-IDEAL sequences during MRI examinations. Two radiologists independently scored the acquisitions of image quality, fat suppression quality, artifacts, vascular and nerve display. The obtained scores were compared using the Wilcoxon signed rank test. According to the signal intensity (SI) measurements, the uniformity of fat suppression, contrast between tumor lesions and subcutaneous fat tissue, and signal-to-noise ratio (SNR) were compared by the paired t-test.
Results
Compared to the T1WI-IDEAL sequence, LAVA-Flex exhibited fewer artifacts (P<0.05), better visualization of nerves and vessels (P<0.05), and performed superior in the fat contrast ratio of the primary lesion and metastatic lymph nodes (0.80 vs. 0.52, 0.81 vs. 0.56, separately, P<0.001). There was no statistically significant difference in overall image quality, tumor signal-to-noise ratio (SNR), muscle SNR, and the detection rate of lesions between the two sequences (P>0.05). T1WI-IDEAL was superior to LAVA-Flex in the evaluation of fat suppression uniformity (P<0.05).
Discussion
LAVA-Flex sequence provides satisfactory image quality and better visualization of nerves and vessels for NPC with shorter scanning times.
... In this chapter, the most frequent pathologies involving the different CNs will be discussed [1][2][3][4][5][6][7][8] with emphasis on the MR techniques that should be used to visualize these lesions at the different CN segments. ...
... This allows selection of the optimal adapted sequences and field of view for this anatomical region [2,8]. The use of intravenous contrast media must be justified and will depend on the clinical presentation, the initial imaging findings, and the potential lesions on the differential (Table 12.2). ...
... CT can be used in the emergency setting to exclude intracranial hypertension prior to lumbar puncture and can also be used to exclude bone metastases. However, in most cases MR is needed to further characterize CN lesions [2,8,21,22]. ...
Neurologists, neurosurgeons, ENT and maxillofacial surgeons, ophthalmologists, and others often detect cranial nerve deficits in their patients but remain uncertain about the underlying cause. It is the radiologist’s task to identify the causative disease, including inflammatory, infectious, vascular, traumatic, tumoral, and neurodegenerative etiologies. To detect this pathology, the neuroradiologist or head and neck radiologist must have a detailed knowledge of the anatomy of the 12 cranial nerves and available MR techniques. Furthermore, selecting the optimal sequences significantly depends on access to the patient’s history, clinical and biological data. In this chapter, emphasis will be put on employing the certain imaging techniques best suited to detect pathologies on the different parts/segments of the cranial nerves: intraaxial, extraaxial intracranial, skull base, and extracranial.
... The parasympathetic fibers of the nervus intermedius originate from the superior salivary nucleus. At the geniculate ganglion, the greater petrosal nerve supplies parasympathetic fibers to the lacrimal gland as well as to the mucosa of the mouth, nose, and pharynx [107][108][109]. ...
The twelve cranial nerves play a crucial role in the nervous system, orchestrating a myriad of functions vital for our everyday life. These nerves are each specialized for particular tasks. Cranial nerve I, known as the olfactory nerve, is responsible for our sense of smell, allowing us to perceive and distinguish various scents. Cranial nerve II, or the optic nerve, is dedicated to vision, transmitting visual information from the eyes to the brain. Eye movements are governed by cranial nerves III, IV, and VI, ensuring our ability to track objects and focus. Cranial nerve V controls facial sensations and jaw movements, while cranial nerve VII, the facial nerve, facilitates facial expressions and taste perception. Cranial nerve VIII, or the vestibulocochlear nerve, plays a critical role in hearing and balance. Cranial nerve IX, the glossopharyngeal nerve, affects throat sensations and taste perception. Cranial nerve X, the vagus nerve, is a far-reaching nerve, influencing numerous internal organs, such as the heart, lungs, and digestive system. Cranial nerve XI, the accessory nerve, is responsible for neck muscle control, contributing to head movements. Finally, cranial nerve XII, the hypoglossal nerve, manages tongue movements, essential for speaking, swallowing, and breathing. Understanding these cranial nerves is fundamental in comprehending the intricate workings of our nervous system and the functions that sustain our daily lives.
... Among the imaging symptoms of MC, atypical cranial nerve enhancement on MRI is sometimes the first or only indication of the disease process [15]. Postgadolinium sequences revealed an enlargement of the cranial nerves and an amplification of primary and secondary tumors that have progressed through the subarachnoid spaces [16]. ...
Purpose
The purpose of this study was to investigate the clinical utility of three-dimension (3D) high-resolution inversion recovery (IR)-prepared fast spoiled gradient-recalled (SPGR) magnetic resonance imaging (MRI) in the diagnosis of cranial nerve meningeal carcinomatosis (MC).
Methods
A total of 114 patients with MC from January 2015 to March 2020 were enrolled and their MRIs were analyzed retrospectively. All patients underwent MRIs before being administered a contrast agent. Both a 2D conventional MRI sequence and a 3D IR-prepared fast SPGR high-resolution T1-weighted (BRAVO) scan sequence were measured after contrast agent administration. The characteristics of MC and the involved cranial nerves were then examined.
Results
Among the 114 MC patients, 81 (71.05%) had cranial nerve enhancement on contrast-enhanced 3D-BRAVO imaging, while only 41 (35.96%) had image enhancement on conventional MRI. The contrast-enhanced 3D-BRAVO displayed stronger image contrast enhancement of the cranial nerves than the conventional MRI (P < 0.001). Furthermore, detection rates for the facial and auditory nerves, trigeminal nerve, oculomotor nerve, sublingual nerve, optic nerve, glossopharyngeal/vagal/accessory nerve, and abductor nerve on contrast-enhanced 3D-BRAVO imaging were 58.77%, 47.37%, 9.65%, 8.77%, 5.26%, 3.51%, and 0.88%, respectively. We found a statistically significant difference between the affected facial and auditory nerves, as well as the trigeminal nerve, oculomotor nerve, sublingual nerve, and optic nerve.
Conclusion
In MC, contrast-enhanced 3D-BRAVO imaging displayed the cranial nerves more effectively than 2D conventional enhanced MRI. The facial, auditory, and trigeminal nerves are the primary nerves involved in MC, and improved scanning of these nerves would aid in the early detection and treatment of MC.
