The role of imaging in skull base osteomyelitis - Reviewed.

PURPOSE: Skull base osteomyelitis (SBO) is difficult to diagnose due to a wide array of clinical presentations. It can be life threatening if not treated promptly. The objective of this study is to identify the various neck spaces involved in skull base osteomyelitis, correlate them with the possible source of infection and identify the related complications. METHODS: Eighty nine consecutive either culture proven cases of skull base osteomyelitis, or culture negative cases with inflammation on histopathology responding to antibiotic therapy, presenting at a single non-government hospital in south India between January 2016 and December 2018 were included in this study. Images were reviewed by two radiologists and imaging findings were documented by consensus. RESULTS: Involvement of the parotid space, retromastoid space and (temporomandibular) TM joint was associated with otogenic source of infection (p value < 0.05); while, retropharyngeal/prevertebral involvement was associated with sphenoid and nasopharyngeal sources (p value < 0.05). Complications such as cavernous sinus thrombosis (p value = 0.023) and ICA involvement (p value = 0.014) were more commonly seen with central skull base osteomyelitis. Abscess formation was seen in all three groups of patients without a significant difference between the groups. CONCLUSION: Imaging plays an important role in determining the possible source of infection by identifying the involved neck spaces and this in turn can guide the clinician to a site for biopsy. Complications related to SBO can also be identified on imaging and can guide appropriate management.

Imaging Spectrum of Cavernous Sinus Lesions with Histopathologic Correlation.

Cavernous sinuses are paired interconnected venous plexuses situated in the floor of the middle cranial fossa on either side of the sella turcica and sphenoid sinus. They are lined by dura mater and consist of multiple venous channels within. The cavernous sinuses are intimately related to the internal carotid artery and its associated sympathetic plexus, the oculomotor nerve, the trochlear nerve, the abducens nerve, and the ophthalmic nerve. Cavernous sinuses are connected to the orbit, the pterygopalatine fossa, the infratemporal fossa, the nasopharynx, and the posterior cranial fossa by various foramina, fissures, and canals in the skull base. A multitude of structures in close relation to the cavernous sinus give rise to a myriad of possible pathologic conditions that can be broadly classified into (a) neoplastic, (b) vascular, (c) infective or inflammatory, or (d) miscellaneous lesions. These pathologic conditions can have overlapping clinical manifestations. Hence, imaging plays a crucial role in identifying the disease, assessing its extent, providing a pertinent differential diagnosis to guide further management, and suggesting a site or route for biopsy. MRI is the modality of choice to depict the cavernous sinuses, with CT and digital subtraction angiography playing supplementary roles in certain situations. In this article, the cavernous sinus lesions encountered in our institution during a 10-year period are reviewed. The purpose of the article is to (a) describe the anatomy of the cavernous sinus; (b) demonstrate the multimodality imaging spectrum of a wide variety of pathologic conditions involving the cavernous sinus, correlating with the histopathologic findings; (c) highlight important imaging clues for differential diagnosis; and (d) help the reader overcome potential pitfalls in interpretation. Online supplemental material is available for this article. ©RSNA, 2019.

Role of penumbra mechanical thrombectomy device in acute dural sinus thrombosis.

BACKGROUND: In dural venous sinus thrombosis (DVST), the mortality ranges 5-30%. Deep venous system involvement and septic dural sinus thrombosis have a higher mortality rate. In acute occlusion, collateral flow may not be established, which may result in significant edema and mass effect. Endovascular interventions may be considered as a treatment option in appropriate high-risk patients with DVST. MATERIALS AND METHODS: Eight patients with magnetic resonance imaging (MRI)-confirmed dural sinus thrombosis, who did not respond to the conventional standard medical treatment, were subsequently treated with mechanical thrombectomy using the Penumbra System®. In all cases, medical treatment including anticoagulants were continued following the procedure for a minimum period of 1 year. RESULTS: Recanalization of the dural sinus thrombosis was achieved in all 8 cases. There were no immediate or late endovascular-related complications. One death occurred due to an unrelated medical event. At 6 months, there was notable improvement in the modified Rankin Score (mRS), with 5/8 (62%) patients achieving mRS of 2 or less. The follow-up ranged between 3 months and 26 months (mean: 14.5 months), and there were no new neurological events during the follow-up period. CONCLUSION: Cerebral venous sinus thrombosis is a rare but life-threatening condition that demands timely diagnosis and therapy. In cases of rapidly declining neurological status despite standard therapy with systemic anticoagulation and anti-edema measures, mechanical thrombectomy could be a lifesaving and effective option. In this study, good outcomes were observed in the majority of patients at long-term follow up.

Recurrent craniospinal subarachnoid hemorrhage in cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) usually manifests as cerebral hemorrhage, especially as nontraumatic hemorrhages in normotensive elderly patients. Other manifestations are subarachnoid (SAH), subdural, intraventricular hemorrhage (IVH) and superficial hemosiderosis. A 52-year-old hypertensive woman presented with recurrent neurological deficits over a period of 2 years. Her serial brain magnetic resonance imaging and computed tomography scans showed recurrent SAH hemorrhage, and also intracerebral, IVH and spinal hemorrhage, with superficial siderosis. Cerebral angiograms were normal. Right frontal lobe biopsy showed features of CAA. CAA can present with unexplained recurrent SAH hemorrhage, and may be the initial and prominent finding in the course of disease in addition to superficial cortical siderosis and intracerebal and spinal hemorrhages.

The current role of transcranial surgery in the management of pituitary adenomas.

The aim of this study was to determine the factors influencing the use of a transcranial (TC) approach in pituitary adenomas and suggest a decision-making tree for the surgical strategy. The data for 23 (4.6%) patients who underwent TC surgery from amongst 494 pituitary adenomas were retrospectively analyzed. Eight factors on magnetic resonance imaging (MRI) that could predict a difficult transsphenoidal (TS) surgery were noted. Adverse findings at TS surgery leading to a 2nd stage TC surgery were documented. Eighteen of the 23 cases were giant adenomas. Thirteen patients underwent TC surgery alone or as an initial approach when combined with TS while 10 underwent 2nd stage TC surgery following a TS approach. Most cases in the first group had 3 or more radiological factors in combination with a small sella. The 2nd group had higher sellar tumor volumes and fewer unfavourable radiological factors that led to the initial use of the TS approach. A hard, fibrous consistency or a significant residue obscured from the surgeon's view, and difficulty in hemostasis were additional factors prompting the use of a TC approach. Tumor excision ≥90% could be achieved in 13 cases (56.5%). Post-operative RT was administered in 12 patients. There were 2 deaths (8.7%) and the major morbidity rate was 43 %. Despite advances in endoscopic surgery the TC approach may be required in 5% of cases. A study of the preoperative MRI for factors that predict difficulty with the TS approach might encourage the surgeon to consider a TC surgery either as an initial approach or combined with a TS surgery.