Arachnoid granulations bulging into the transverse sinus, sigmoid sinus, straight sinus, and confluens sinuum: a magnetic resonance imaging study

Large arachnoid granulation protruding into the transverse sinus: A probable cause of intermittent otologic symptoms

A 69-year-old woman suffered attacks of hearing disturbance and vertigo for seven years. Her otologic and ophthalmological examinations did not show any significant findings. Cerebral magnetic resonance imaging revealed a cystic mass in the left cerebellar convexity. Computed tomography demonstrated a contrast defect of the distal left transverse sinus. Magnetic resonance imaging revealed a cyst protruding into the transverse sinus, and enlarging in the supine. Cerebral angiography demonstrated a congestive venous flow in the left transverse sinus, at the upstream of the cyst. At rest, the venous sinus pressure was 13 cm H2O at the upstream of the cyst and 8 cm H2O at the downstream. When the patient held a breath, the upstream pressure increased to 37 cm H2O, while the maximal downstream pressure was 22 cm H2O. A large AG protruding into the cranial dural sinus may cause intermittent venous congestion and associated otologic symptoms. Movements accompanied by a transient decrease in cardiac venous return and changes in head position can attribute to an enlargement of such AG.

Granular Foveolae in the Groove of the Sigmoid Sinus: An Anatomical Study

Background Granular foveolae in the groove of the sigmoid sinus have rarely been reported in the literature compared to numerous published reports on the granular foveolae near the superior sagittal sinus and its sulcus on the internal aspect of the calvaria. The present study was performed to better elucidate their prevalence and locations. Materials and methods One hundred and ten adult dry skulls (220 sides) were analyzed for the presence of granular foveolae within the groove of the sigmoid sinus. The exact position of the foveolae was documented, and the diameter of the granular foveola was measured. Results Granular foveolae were found in the groove of the sigmoid sinus on 3.6% of the sides. These were at or within a mean of 1.3 cm inferior to the transverse-sigmoid junction. When a mastoid foramen was noted in the groove, it was always located inferior to the granular foveolae when present. The mean diameters of the granular foveolae of the left groove of the sigmoid sinus were 2.8 mm and 4 mm for the right grooves. The mean depth of the granular foveolae in the left groove of the sigmoid sinus was 2.7 mm and 3.5 mm for the right grooves. Granular foveolae were statistically larger and deeper on the right versus left sides (p<0.05). Conclusions Granular foveolae of the groove of the sigmoid sinus were identified most commonly on the right sides and 3.6% on all sides. If identified on medical imaging, these uncommon structures at the skull base should be considered normal anatomical variations.

Optic nerve sheath fenestration for treating papilloedema in the era of cerebral venous sinus stenting

BACKGROUND

Pseudotumour cerebri (PTC) is the syndrome of intracranial hypertension without intracranial mass or hydrocephalus and is the commonest cause of papilloedema seen in many eye clinics. In the last 10 years, we have increasingly used TSS in patients whose papilloedema was not well controlled with medical treatment and have done fewer ONSFs. Here, we review our experience at Royal Prince Alfred Hospital Sydney with ONSF in 35 patients over the period 2002-2021.

METHODS

Retrospective case series of 35 patients, 30 of whom had primary PTC [i.e., idiopathic intracranial hypertension (IIH)] and 5 with secondary PTC.

RESULTS

Eighteen patients had bilateral ONSF and 17 patients unilateral ONSF, in each case of the worse eye. Thirteen patients then underwent transverse sinus stenting (TSS), in each case following ONSF. The primary outcome measures were visual acuity (VA) and mean deviation (MD) on visual field (VF) testing. MD improved by 5 dB or more in 34 of 70 total eyes (48.6%); VA improved by 0.2 logMAR (two lines on Snellen chart) or more in 21 eyes (30%), and by both in 15 eyes (21.4%). Final MD was -10 dB or better in 38 eyes (54.3%); final VA was 0.3 (6/12) or better in 54 eyes (77.1%), and both in 39 eyes (55.7%).

CONCLUSIONS

The results confirm that ONSF can relieve papilloedoema in both eyes and improve both VF and VA, even in cases of fulminant PTC with severe acute visual impairment.

Brain Vascular Microenvironments in Cancer Metastasis

Primary tumours, particularly from major solid organs, are able to disseminate into the blood and lymphatic system and spread to distant sites. These secondary metastases to other major organs are the most lethal aspect of cancer, accounting for the majority of cancer deaths. The brain is a frequent site of metastasis, and brain metastases are often fatal due to the critical role of the nervous system and the limited options for treatment, including surgery. This creates a need to further understand the complex cell and molecular biology associated with the establishment of brain metastasis, including the changes to the environment of the brain to enable the arrival and growth of tumour cells. Local changes in the vascular network, immune system and stromal components all have the potential to recruit and foster metastatic tumour cells. This review summarises our current understanding of brain vascular microenvironments, fluid circulation and drainage in the context of brain metastases, as well as commenting on current cutting-edge experimental approaches used to investigate changes in vascular environments and alterations in specialised subsets of blood and lymphatic vessel cells during cancer spread to the brain.