Lesions and Pseudolesions of the Cavernous Sinus and Petrous Apex
Section snippets
Parasellar structures
The cavernous sinus consists of bilateral structures containing multiple small venous sinusoids [5]. Its floor rests on the intracranial surface of the sphenoid and temporal bones. A groove on the surface of the sphenoid bone is termed the carotid sulcus and marks the course of the horizontal segment of the intracavernous carotid. The medial wall of the cavernous sinus has a sellar portion (facing the pituitary and sella) and a sphenoidal portion (facing the body of the sphenoid). The lateral
Petrous apex anatomy
The petrous portion is the most medial aspect of the temporal bone. It is bounded medially by the petro-occipital synchondrosis (see Fig. 2), which contains embryonic rests capable of becoming chondroid neoplasms. In sagittal plane, the petrous bone has a triangular shape with anterior wall forming the posterior margin of the middle cranial fossa and the posterior wall forming the anterior margin of the posterior cranial fossa. The tentorium attaches to the apex of the triangle, with the
Imaging techniques
CT examination is best performed on a multislice scanner with axial images reconstructed at 1.25-mm or smaller intervals. Although direct coronal images were once performed, coronally oriented reformats are now technically excellent and minimize radiation dose to the patient. Both soft tissue and bone reconstructions should be performed; the latter can evaluate for subtle osseous erosion or remodeling.
Although MRI lacks the bony definition of CT, it is invaluable for demonstrating subtle soft
Parasellar lesions
Aneurysms of the cavernous carotid represent a small fraction of all cerebral aneurysms, but figure in the differential diagnosis of cranial nerve palsies. Although catheter angiography remains the gold standard for aneurysm imaging, this diagnosis should always be borne in mind when viewing CT and MRI scans of the skull base. On the most commonly used MRI sequences (spin echo), moving fluid appears as signal dropout (flow void). Unfortunately, any air-containing structure also shows signal
Petrous apex lesions
The petrous apex is pneumatized in approximately 33% of individuals. Pneumatization is asymmetric in many instances; this should be considered a normal variant and not a lesion. With the growing use of MRI as initial brain screening examination, marrow signal in the nonpneumatized apex can be misinterpreted as a mass (Fig. 12). Confirmation with noncontrasted CT examination demonstrates a nonexpansile area of fat attenuation similar to normal marrow elsewhere. Like the mastoid air cells and
Postprocedural findings
Cephaloceles result from defects in the floor of the cranium, either congenital or acquired. Iatrogenic defects are possible after surgery to either the central skull base or petrous region. Suspicion for iatrogenic dural defect should arise when pneumocephalus persists for more than a few days postoperatively. Congenital cephaloceles are much less common in the petrous apex region than in the frontonasal and ethmoidal regions, but do occur. Thin-section CT is most sensitive for bone defects,
References (21)
- et al.
Endoscopic approaches to the petrous apex
Operative Techniques in Otolaryngology
(2006) - et al.
Evaluation of magnetic resonance imaging criteria for cavernous sinus invasion in patients with pituitary adenomas: logistic regression analysis and correlation with surgical findings
Surg Neurol
(2006) - et al.
Neurosarcoidosis—review of the imaging findings
Semin Roentgenol
(2004) MR imaging of perineural tumor spread
Neuroimaging Clin N Am
(2004)- et al.
Endoscopic endonasal approaches to the cavernous sinus: surgical approaches
Neurosurgery
(2001) - et al.
Expanded endonasal approach to the sella and anterior skull base
- et al.
Expanded endonasal approach: fully endoscopic, completely transnasal approach to the middle third of the clivus, petrous bone, middle cranial fossa, and infratemporal fossa
Neurosurg Focus
(2005) - et al.
Microsurgical anatomy and approaches to the cavernous sinus
Neurosurgery
(2005) - et al.
The medial wall of the cavernous sinus: microsurgical anatomy
Neurosurgery
(2004) - et al.
A new concept in Dorello's canal microanatomy: the petroclival venous confluence
J Neurosurg
(1997)
Cited by (16)
Imaging of Petrous Apex Lesions
2021, Neuroimaging Clinics of North AmericaCitation Excerpt :Imaging characteristics of common petrous apex lesions are summarized in Table 1. The petrous apex is pneumatized in approximately 33% of individuals.11 Petrous apex pneumatization is found in 21% of children, with prevalence and degree increasing with age.12
Gamma Knife surgery for a hemangioma of the cavernous sinus in an adult: Case report and short review of the literature
2017, NeurochirurgieCitation Excerpt :Cavernous sinus hemangiomas (CSH) are rare benign extra-axial vascular lesions comprising up to 3% of all benign tumors within the cavernous sinus [1]. However, within the cavernous sinus (CS) are the most common primary tumor along with schwannomas and meningiomas [2,3]. The CS itself contains vital neurovascular structures, and so patients might present with a CS syndrome with one or more cranial nerve (III-VI) palsies associated with painful ophtalmoplegia [1] or later with symptoms due to mass effect.
Clinical Features, Management Considerations and Outcomes in Case Series of Patients with Parasellar Intracranial Aneurysms Undergoing Anterior Skull Base Surgery
2017, World NeurosurgeryCitation Excerpt :The risk of an untreated or unrecognized IA during transsphenoidal surgery is acute vascular injury or IA rupture.29,47,48 Intraoperative ICA injury is a rare, but well-known, complication of anterior skull base surgery and is reported to occur in 0.16%–0.5% of cases.49-51 Intraoperative rupture of an IA coexisting with a pituitary adenoma may result in SAH or rupture into the surgical field and sphenoid sinus.52
Excavating Meckel's cave: Cavum-trigeminale-cephaloceles (CTCs)
2015, Journal of NeuroradiologyCitation Excerpt :Indeed, none of the lesions in our study revealed a restricted diffusion. Some differential diagnosis can be ruled out by DWI, since they present with restricted diffusion, such as epidermoids [9] including congenital cholesteatoma [10,11]. CTCs usually exhibit sharply demarcated margins [3,7].
Low field MR imaging of sellar and parasellar lesions: Experience in a developing country hospital
2012, European Journal of RadiologyCitation Excerpt :Radiological imaging of the sellar and parasellar region is challenging since the sella is a small volume region in close proximity to many complex structures [2]. Both CT and MRI play vital roles in the anatomical delineation of lesions in this area [17]. MRI is the modality of choice as it provides high contrast multiplanar images, whereas CT has a complementary role in delineating bony architecture demonstrating calcifications [5].
Cavernous sinus: anatomy, histology and terminology
2023, Cirugia y Cirujanos (English Edition)