Article Figures & Data
Figures
- FIGURE 1.
Ventriculoperitoneal shunt valve, usually implanted subcutaneously just behind ear. Proximal tubing connects to Rickham reservoir. Distal tubing goes to peritoneal cavity. Proximal and distal occluders can be pressed and held manually to occlude flow. Silicone dome is then pressed to force flow in one direction or other. Silicone dome is designed to be pierced by hypodermic needle for sampling or injection. Rickham reservoir is placed beneath skin at top of head and provides connection between catheter into ventricles and proximal shunt tubing. Either silicone dome can be accessed for ventriculoperitoneal shunt study.
- FIGURE 2.
(A) Radionuclide CSF ventriculoperitoneal shunt evaluation. (B) Supply setup for ventriculoperitoneal shunt study. (C) Injection syringe (left) and distal connection to butterfly catheter (right). It is important that connection is fluid to fluid, so that no air is injected into valve. Menisci are seen at both sides immediately before connection. (D) Most common outcomes of radionuclide ventriculoperitoneal shunt studies.
- FIGURE 3.
(A) Normal study (normal opening pressure; normal T½) in 72-y-old woman with history of normal-pressure hydrocephalus, now with gait instability and worsening symptoms. Opening pressure was 7 cm water with T½ of 2.5 min. Anterior abdomen image shows good dispersion. (B) Overdrainage (or syphoning) (normal or low opening pressure; increase of flow when positioned semiupright) in 50-y-old man with ventriculoperitoneal shunt placed for subarachnoid hemorrhage 6 y ago, now with worsening somnolence. Opening pressure was 10 cm water, with initial T½ of 20 min, increasing to 1 min after patient sat semiupright. Anterior abdomen image shows good dispersion. (C) Distal obstruction (high opening pressure; slow flow) in 12-y-old girl with ventriculoperitoneal shunt placed for congenital hydrocephalus, now with lethargy, nausea, and vomiting. Opening pressure was 29 cm, with T½ of 10 min. Anterior abdomen image shows good dispersion in delayed imaging. (D) Proximal obstruction (low opening pressure; slow flow) in 4-mo-old boy with congenital hydrocephalus, now with periodic spells of apnea. Opening pressure was 1 cm, with T½ of 10 min.
- FIGURE 4.
(A) Kinking (normal flow with abrupt cessation of flow with change in position) in 80-y-old woman with history of normal-pressure hydrocephalus. Ventriculoperitoneal shunt was placed 13 y previously. Patient was now having increasing trouble with balance and urinary control. Opening pressure was 6 cm, with initial T½ of 2 min. Flow stopped when patient sat semiupright and resumed after she turned her head. (B) CSF-oma (pattern of distal obstruction but with focal uptake in abdomen) in 32-y-old man with history of childhood brain tumor that had been resected and ventriculoperitoneal shunt placed. Patient now had 1- to 2-wk history of headache. Opening pressure was 14 cm, with initial T½ of 5 min. Anterior abdomen image shows loculation. (C) Inadvertent air in system in 64-y-old man with history of normal-pressure hydrocephalus and recent head injury, now experiencing worsening problems with balance and memory. Opening pressure was negative. Butterfly catheter was left open for about 1 min. Air entered system and caused temporary blocking of flow. Activity was seen in abdomen after 15 min of ambulation, showing that flow had restarted. Diagnosis is probable overdrainage. (D) Perivalvular injection in 47-y-old woman with history of ventriculoperitoneal shunt placement in 1990 for idiopathic intracranial hypertension. Opening pressure was 0 cm, with initial T½ of 8 min. Important point in this study is that efferent tubing is not visualized, even on lower set of dynamic images, with intensity increased. Faint activity seen in left neck may be diffusion along tract of tubing. We confirmed that this was not ventriculoatrial shunt, since tubing was seen in abdomen on recent radiograph. Activity over injection site is decreasing because of diffusion into neighboring tissue. Stomach activity is seen at end because pertechnetate diffuses into bloodstream and is taken up by gastric mucosa.
