Predictive value of quantitative cisternography in normal pressure hydrocephalus.

Area of Science:

• Neurology
• Nuclear Medicine
• Radiochemistry

Background:

• Normal pressure hydrocephalus (NPH) is a neurological condition characterized by impaired cerebrospinal fluid absorption.
• Accurate diagnosis and prediction of surgical outcomes in NPH are crucial for patient management.

Purpose of the Study:

• To evaluate the utility of quantitative radionuclide cisternography in assessing NPH.
• To correlate cisternographic findings with outcomes following ventriculo-peritoneal shunt surgery.

Main Methods:

• Quantitative cisternography was performed on 25 NPH patients and 16 with cerebral atrophy.
• A lumbar injection of 99mTc DTPA was administered, with anterior head imaging at 3, 6, and 24 hours.
• Radioactivity in the lateral ventricles, basal cisterns, hemispheric convexities, and total intracranial region was measured and ratios calculated.

Main Results:

• The ratio of ventricular to total intracranial activity (V/T) positively correlated with improvement after shunt surgery in NPH patients.
• All NPH patients with a V/T ratio >32% showed improvement, while a ratio <32% did not rule out improvement.
• Radionuclide cisternography could be simplified to a 24-hour imaging protocol for quantitative measurements.

Conclusions:

• Quantitative cisternography, particularly the V/T ratio, is a valuable tool for predicting shunt surgery outcomes in NPH.
• A 24-hour imaging protocol is sufficient for quantitative assessment, streamlining the diagnostic procedure.