MR imaging of intramedullary and intradural-extramedullary spinal cysticercosis

OBJECTIVE

The purpose of our study was to retrospectively review the MR imaging findings in a group of patients with clinically proven cysticercosis involving the spinal cord, the spinal subarachnoid space, or both.

MATERIALS AND METHODS

We retrospectively reviewed images of 16 patients with clinically diagnosed spinal cysticercosis to summarize the imaging characteristics. All patients underwent T1- and T2-weighted sagittal, axial, or both sagittal and axial MR imaging before i.v. administration of paramagnetic contrast media. Thirteen patients also underwent sagittal, axial, or both sagittal and axial T1-weighted MR imaging after i.v. gadolinium administration. In addition, all patients underwent cranial CT, MR imaging, or both to reveal possible evidence of cranial cysticercosis.

RESULTS

MR imaging revealed isolated intradural-extramedullary involvement (n = 9), isolated intramedullary involvement (n = 3), combined intradural-extramedullary and intramedullary involvement (n = 3), and/or syringomyelia caused by infection and associated with chronic spinal arachnoiditis (n = 2). Evidence of intradural-extramedullary disease included cystic structures within the subarachnoid space or homogeneous sheetlike enhancement within the subarachnoid space over the surface of the spinal cord. Evidence of intramedullary disease included focal cystic lesions or syringomyelic cavitation of the spinal cord. All patients had evidence of simultaneous intracranial cysticercosis as shown on cranial CT, MR imaging, or both.

CONCLUSION

In the absence of scolex visualization, cysticercotic involvement of the spinal cord or spinal subarachnoid space has a nonspecific appearance on MR imaging. On the basis of the findings in this group of patients, we believe that spinal cysticercosis is most often accompanied by intracranial disease.

Frontal foramina in pediatric skull in cases of congenital hydrocephalus

PURPOSE

To describe a new observation, frontal calvarial foramina, in pediatric patients with congenital hydrocephalus secondary to central nervous system malformation.

MATERIALS AND METHODS

Frontal foramina were initially identified in three female patients with Chiari II malformation. Subsequently, head computed tomographic (CT) scans in 99 patients with congenital hydrocephalus were retrospectively reviewed. CT scans in a control group of 116 patients without hydrocephalus were also retrospectively reviewed.

RESULTS

Frontal foramina were found in eight of 61 (13%) patients with Chiari II malformation, in one child with Dandy-Walker malformation, and in one child with occipital horn dilatation (colpocephaly), but not in control patients. Sequential CT examinations in three patients with frontal foramina depicted gradual closure after ventriculoperitoneal shunt placement.

CONCLUSION

Frontal foramina may represent an abnormality variably expressed in certain central nervous system malformations that cause congenital hydrocephalus. The presence of frontal foramina palpated or visualized on plain radiographs may help in the diagnosis of congenital hydrocephalus and central nervous system malformation.

Progressive ventricular enlargement in cats in the absence of transmantle pressure gradients

Intracranial pressure (ICP) was measured simultaneously at multiple sites in cats to determine if transmantle pressure gradients were present in progressive hydrocephalus. The cats underwent craniectomy and intracisternal injection of kaolin; 4 to 9 weeks later ICP was measured at the ventricle, cisterna magna, and convexity subarachnoid space, and in the brain tissue and the sagittal sinus. In 13 cats in which ventricular size conformed to previously established norms for duration of hydrocephalus, there were no demonstrable gradients of pressure at any of the sites of measurement according to one-way analysis of variance (p greater than 0.05). The mean (+/- standard error of the mean) peak and trough pressures (in mm Hg) at each site were: ventricle, 12.7 +/- 0.7 and 12.0 +/- 0.6; cisterna magna, 12.9 +/- 0.8 and 12.3 +/- 0.7; subarachnoid space, 12.7 +/- 0.8 and 12.1 +/- 0.7; brain tissue, 12.9 +/- 0.9 and 12.4 +/- 0.9; and sagittal sinus, 13.1 +/- 0.8 and 11.9 +/- 0.8. These results indicate that ventricular expansion can progress without measurable transmantle pressure gradients.

Carotid occlusion in cysticercosis

A man without orthostatic hypotension had transient ischemic attacks that were initiated by upright posture. CT showed a cystic mass in the interhemispheric fissure and basilar cisterns. Cerebral angiography demonstrated supraclinoid occlusion of the right internal carotid artery. At frontal craniotomy, cysticercosis cysts were found adherent to a pulseless right internal carotid artery. This is the first antemortem documentation of a large artery occlusion directly related to Cysticercosis racemosus.