Regression of cerebellar tonsillar descent and hydrocephalus after endoscopic third ventriculostomy in a patient with a quadrigeminal arachnoid cyst.

BACKGROUND: Posterior fossa arachnoid cysts, including quadrigeminal cistern arachnoid cysts, can occasionally cause compression of the quadrigeminal plate, leading to Sylvian aqueduct stenosis and induction of cerebellar tonsillar descent into the foramen magnum. This, in turn, can result in obstructive hydrocephalus. In such cases, the characteristic of hydrocephalus is generally considered to be hypertensive. CASE DESCRIPTION: We present the case of a 28-year-old female complaining of chronic and progressively worsening headaches following the delivery of her first child. Magnetic resonance imaging revealed marked tri-ventriculomegaly, the arachnoid cyst located in the quadrigeminal cistern, and cerebellar tonsillar descent. Ophthalmoscopy revealed bilateral papilledema indicating a long-standing elevation of intracranial pressure. Endoscopic third ventriculostomy (ETV) was performed successfully and resulted in complete recovery from her headaches and papilledema. Postoperative MRI revealed resolution of ventriculomegaly and cerebellar tonsillar descent, suggesting that the fourth ventricle outlet obstruction was associated with the development of the hydrocephalus in this patient. CONCLUSION: Our case is the first report that a quadrigeminal arachnoid cyst associated with both cerebellar tonsillar descent and hydrocephalus was well treated with ETV. It was indicated that the patient's hydrocephalus and cerebellar tonsillar descent were secondary and synergistic events, caused by the arachnoid cyst located in the quadrigeminal cistern.

Ectopic ossification in the cranial dura mater in dialysis patients with secondary hyperparathyroidism.

We report the case of a 69-year-old woman with secondary hyperparathyroidism who underwent maintenance haemodialysis therapy for 17 years and who presented with severe dural calcification and right subdural haematoma. Her dura mater displayed a rock barnacle-like appearance, and cerebral superficial arteries adhered to the sclerotic lesions. On the microscopic observation, calcified tissue with a clear lamellar structure and osteopontin immunoreactivity was observed. Tartrate-resistant acid phosphatase immunoreactive polynucleated giant cells infiltrated around the tissue. Such morphological properties are specific to the calcified tissue formed through a bone formation-like mechanism that is often observed in arterial media in patients with chronic kidney disease.

Diffusion-perfusion mismatch in symptomatic vasospasm after subarachnoid hemorrhage.

Diffusion-weighted and perfusion-weighted magnetic resonance (MR) imaging were investigated as a method to detect diffusion-perfusion mismatch in the early stages of vasospasm in 17 patients with acute subarachnoid hemorrhage after aneurysm clipping. Single photon emission computed tomography (SPECT) with N-isopropyl-p-[(123)I]iodoamphetamine was also performed. Diffusion-perfusion mismatch was clearly identified in the 3 patients who manifested clinical deterioration. Perfusion-weighted imaging showed increased mean transit time, normal cerebral blood flow, and increased or normal cerebral blood volume. SPECT revealed no earlier signs of vasospasm. Diffusion-perfusion mismatch was clearly demonstrated in the early stages of vasospasm, so may be useful for early identification of ischemia in vasospasm and initiating appropriate treatment.

[Detailed magnetic resonance imaging of abducens nerve by 3D-CISS].

Although abducens nerve palsy is a relatively common disease, the abducens nerve has been almost impossible to identify, because it is one of the finest cranial nerves and runs three-dimensionally in the prepontine cistern. Three-dimensional constructive interference in steady state (3D-CISS) is helpful in visualizing fine structural elements in the central nervous system because of its higher spatial resolution and fewer artifacts from cerebrospinal fluid. In this study, we successfully visualized the abducens nerve using 3D-CISS. The procedures were as follows: first, Dorello's canal and the ponto-medullary sulcus were identified as visible landmarks, and then the abducens nerve was followed to the root exit zone; second, the gray scale of the original image was inverted to clearly visualize the cisternal course of the nerve and the neighboring small vessels; and, finally, the entire cisternal course of the nerve was visualized in the same images in both oblique axial and oblique sagittal planes by a multi-planar reconstruction method. This reliable technique can be performed for the diagnosis of abducens nerve palsy.