Three-Dimensional Computed Tomography Reconstruction Unmasks Shunt Disconnection in a Child

Figure 2: 3D reconstruction of CT head scan prior to shunt exploration showed clear disconnection of the proximal catheter from the shunt valve. Shunt disconnection is the cause of malfunction in approximately 10% of cases.1 Diagnosing shunt disconnection with shunt series X-rays may prove difficult as the disconnection may be subtle, as in our case, and the shunt may still be partially functional which can manifest as inconsistent and intermittent symptoms.2,3 The negative predictive value of shunt series X-rays is only 22%.4 3D visualization of the shunt by reconstruction of a multidetector CT scan provides much better clarity of shunt components.3 These 3D reformats can be easily generated from the original CT dataset from a multidetector CT available in most imaging departments today and do not require any increased radiation dose. In our institution, patients with suspected shunt malfunction who have CT brain imaging on admission are now receiving routine radiological evaluation with 3D-CT reconstructions to facilitate the detection of obscure shunt fractures and disconnections.