Metrizamide and radionuclide cisternography in communicating hydrocephalus

Area of Science:

• Neuroradiology
• Nuclear Medicine
• Diagnostic Imaging

Background:

• Assessing cerebrospinal fluid (CSF) dynamics is crucial for diagnosing conditions like hydrocephalus.
• Conventional imaging methods may have limitations in fully characterizing CSF flow and absorption.

Purpose of the Study:

• To compare the efficacy of simultaneous 111In-DTPA and metrizamide CT cisternography in evaluating CSF dynamics.
• To determine the predictive value of serum iodine levels and plain CT findings for abnormal CSF flow.

Main Methods:

• Simultaneous administration of 111In-DTPA and metrizamide for CT cisternography.
• Imaging performed on 9 normal subjects and 11 patients with suspected communicating hydrocephalus.
• Analysis of tracer clearance, absorption sites, and correlation with serum iodine levels and plain CT findings.

Main Results:

• Both 111In-DTPA and metrizamide demonstrated similar CSF clearance patterns.
• Significant CSF absorption was observed in the spinal dural sac.
• Elevated serum iodine levels at 48 hours correlated with persistent ventricular penetration but not with abnormal ventricular stasis.
• Plain CT findings of ventricular and sulcal enlargement did not reliably predict abnormal dynamic cisternogram results.

Conclusions:

• Simultaneous 111In-DTPA and metrizamide CT cisternography provide comparable qualitative assessment of CSF dynamics.
• Serum iodine levels are not a reliable predictor of CSF stasis.
• Dynamic cisternography remains essential for evaluating abnormal CSF flow, as plain CT findings are insufficient for prediction.