Evaluation of whole body Ultralow-Dose CT for the assessment of ventriculoperitoneal shunt complications: an experimental ex-vivo study in a swine model.

Abstract

OBJECTIVE: To evaluate the suitability of whole body Ultralow-dose CT (ULD-CT) as a diagnostic tool for the evaluation of ventriculoperitoneal shunt (VP-shunt) complications with special regards to radiation dose and image quality. METHODS: Fourteen VP-shunts were implanted in 7 swine cadavers (weight: 55-70 kg). Twenty-two mechanical complications (extracranial and extraperitoneal malpositioning, breakages, disconnections) were induced in nine VP-shunts. Ten ULD-CT scans with different parameters (tube voltage: 80, 100, 120 kV; tube current: 20 or 50 mAs; Pitch (P): 1 or 1.5) were acquired; the combination of 120 kV and 50 mAs was omitted. Radiation dose estimation, blinded readings, and quantitative and qualitative assessment of the CT-data were performed. RESULTS: Effective radiation doses varied between 0.44 ± 0.06 and 2.55 ± 0.35 mSv. ULD-CT protocols provided a mean sensitivity (i.e., correctly detected shunt complications) of 98.2 %. Unnoticed or incorrectly identified complications did not exceed one complication (4.5 %) in any ULD-CT protocol. Diagnostic confidence was sufficient for all ULD-CT protocols except for protocols with 80 kV and 20 mAs. CONCLUSIONS: ULD-CT allows accurate detection of VP-shunt complications at radiation doses similar or lower than reported for a radiographic shunt series. At the tested radiation dose levels, ULD-CT thus provides an alternative to a radiographic shunt series. KEY POINTS: • Ultralow-dose CT accurately detects Ventriculoperitoneal Shunt complications. • Radiation dosage is similar or lower than reported for a radiographic shunt series. • Ultralow-dose CT potentially shortens the diagnostic process when shunt complications are suspected.