Evaluating the role of isotope 99mTc-DTPA cisternography in the diagnosis of normal pressure hydrocephalus: A retrospective analysis

Abstract

Normal Pressure Hydrocephalus (NPH) is a potentially reversible neurological disorder predominantly affecting the elderly, characterized by a clinical triad of gait disturbance, cognitive impairment, and urinary incontinence. Despite advances in MRI and CT imaging, accurate diagnosis remains challenging due to symptom overlap with other neurodegenerative diseases. Radionuclide cisternography provides a dynamic assessment of cerebrospinal fluid (CSF) flow, which may enhance diagnostic accuracy. We conducted a retrospective case series of 19 adult patients evaluated for suspected NPH between 2018 and 2024. All underwent radionuclide cisternography alongside MRI, CT, lumbar puncture, and clinical assessments. Diagnosis was based on accepted clinical and radiological criteria. Cisternography findings were classified according to ventricular reflux and convexity flow patterns. Treatment response was assessed following ventriculoperitoneal (VP) shunt placement. The cohort's mean age was 64 years with equal sex distribution. Gait disturbance was universal, urinary incontinence affected 68.4%, and cognitive impairment was noted in 78.9%. Cisternography was positive in 78.9%, MRI in 89.5%, and CT in 52.6%. Only 42.1% showed concordant positivity across all imaging. Lumbar puncture opening pressures were normal in most patients. Following VP shunting, 84.2% improved clinically, primarily gait function. Complications included infection, shunt revision, and one subdural hematoma. Radionuclide cisternography remains a valuable adjunct in diagnosing NPH, especially when conventional imaging and clinical features diverge. Its ability to assess CSF dynamics complements static imaging, aiding in timely diagnosis and management to optimize patient outcomes.