Diagnostic value of CT cisternography with intrathecal metrizamide enhancement, comparison with isotope cisternography

Intrathecal Contrast-enhanced Computed Tomography and MR Cisternography for Skull Base Cerebrospinal Fluid Leaks and Other Intracranial Applications

Acquired skull base cerebrospinal fluid (CSF) leaks can result from trauma, tumors, iatrogenic causes, or may be spontaneous. Spontaneous skull base CSF leaks are likely a manifestation of underlying idiopathic intracranial hypertension. The initial assessment of rhinorrhea or otorrhea, which may be suspected owing to an acquired skull base CSF leak, requires integration of clinical assessment and biochemical confirmation of CSF. When leaks are multiple or if samples of fluid cannot be obtained for testing, then recourse to intrathecal contrast-enhanced cisternography may be necessary. We also review various other applications for diagnosis of intracranial abnormalities using contrast-enhanced cisternography.

CT cisternography in intracranial symptomatic arachnoid cysts: classification and treatment

OBJECTIVES

The symptom and neuroimaging as indications for treating arachnoid cysts (ACs) are not adequate. Understanding the communication between cyst and subarachnoid space is helpful for decision-making. We took a dynamic study of ACs using CT cisternography (CTC) and proposed a classification of arachnoid cysts.

MATERIALS AND METHODS

Total 52 symptomatic patients with ACs were enrolled in this prospective study. CTC images were ordered, in all enrolled patients, at the 1, 3, 6, 12, 24 and 48 h after the intrathecal Omnipaque administration. Enhancement in cysts was measured quantitatively and was compared with neighboring subarachnoid spaces. All enrolled patients were allocated randomly in 2 groups. The CTC result was considered before treatment in one group (CTC group), while another group was surgically treated without considering CTC results (surgical group).

RESULTS

ACs in our study were classified into 3 types: complete (cyst filling time at 1 h), incomplete (filling time began at 3 h) and noncommunicating cysts (no or slight filling after 24 h). Twenty-two patients in CTC group with incomplete communicating, or noncommunicating cysts underwent surgeries. And other 6 patients with complete communicating cysts were closely observed. In CTC group, the symptom of all surgical patients was relieved, and 5 out of 6 observational patients showed clinical improvement or no deterioration during the follow-up. In surgical group, only 18 out of 24 patients showed clinical improvement after surgeries, and there were 6 patients showing no difference before and after surgeries in symptom and in imaging.

CONCLUSIONS

This classification based on dynamic CT cisternography is useful for the decision of surgical indication. Some symptomatic patients with complete communicating ACs may not need surgical intervention.

Normal pressure hydrocephalus: did publications alter management?

Forty six Dutch neurologists and neurosurgeons were interviewed to evaluate the clinical value of research articles on normal pressure hydrocephalus (NPH). From this survey it appears that most clinicians still limit investigations to psychometry, CSF-tap test(s), and cisternography. The main reasons for not using other techniques were: their invasiveness, technical complexity, poor availability, lack of time and doubt on their additional predictive value. There is an obvious discrepancy between the quantity of publications on NPH and their impact and their ability to assist clinicians in selecting potential NPH patients for a shunt.

Diagnosis of epidermoid cysts by metrizamide CT cisternography

The authors describe three cases of intracranial epidermoid cysts specifically diagnosed by metrizamide CT cisternography. In CT cisternography of epidermoid cysts, metrizamide enters deep in the tumor clefts and depicts the lobulated margin of the tumor. We consider these findings are specific for this tumor and similar to the findings reported previously in pneumoencephalography or positive contrast cisternography.

A variant of normal-pressure hydrocephalus simulating Pick's disease on computerized tomography. Report of two cases

The authors present two cases of normal-pressure hydrocephalus that simulated Pick's disease radiographically and that were initially diagnosed as cortical atrophy. In both cases, Sylvian cisternoperitoneal shunts improved the clinical picture only temporarily, but ventriculoperitoneal shunting produced dramatic relief of all symptoms.

Experiences with intrathecally enhanced computed tomography

Computed tomographic cisternography (CTC) shows small normal and pathological structures in the extracerebral CSF spaces in an excellent way and is able to differentiate communicating from non-communicating CSF-containing cysts in congenital malformations and acquired lesions. The main value of the CTC is in the examination of CSF dynamics. A report is given about our experiences with 121 patients. The dynamic flow patterns are divided into eight groups. The results are discussed in detail with suggestions as to the treatment.