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The symptoms of shunt failure are non-specific – headache, nausea, lethargy – so diagnostic tests must be conducted to rule in or rule out surgery. Current methods of diagnosing shunt malfunction, including CT Scan, MRI, radionuclide studies and shunt tap, have limitations and risks.
Slit ventricle syndrome is an uncommon disorder associated with shunted patients, but results in a large number of shunt revisions. The condition usually occurs several years after shunt implantation. The most common symptoms are similar to normal shunt malfunction, but there are several key differences.
The key to Phase-contrast MRI (PC-MRI) is the use of a bipolar gradient. [4] A bipolar gradient has equal positive and negative magnitudes that are applied for the same time duration. The bipolar gradient in PC-MRI is put in a sequence after RF excitation but before data collection during the echo time of the generic MRI modality.
The revision of a shunt means to replace or make adjustments to all or part of the shunt, this also means that the location of the shunt may be changed therefore changing the category or type of shunt a patient has. For some patients with shunts, a revision or multiple revisions to the shunt may be required. This can be something minor, such as ...
The shunt also has a valve which serves to maintain one-way flow of the CSF and regulates the flow rate. The end with the catheter is placed in the third ventricle to drain the excess CSF and the other end is placed in the peritoneal cavity or atrium of the heart (making it a ventriculoperitoneal or ventriculoatrial shunt, respectively). The ...
A ventilation perfusion scan or lung scintigraphy can be used to diagnose areas of lungs being ventilated but not adequately perfused. This results in a raised Alveolar-arterial (A-a) gradient which is responsive to supplemental oxygen. In conditions with right to left shunts, there are also ventilation perfusion defects with high A-a gradients.
Shunt obstruction is the most common cause of shunt failure. [68] The shunt can be obstructed at the catheter or the valve itself. Cases of shunt obstruction would present with similar symptoms to untreated hydrocephalus (headaches, nausea, lethargy, etc.). [68] It can be caused by tissue, bacteria, or kinking of the catheter.
When catheter drainage is permanent, it is usually referred to as a shunt. There are many catheter-based ventricular shunts that are named for where they terminate, for example, a ventriculoperitoneal shunt terminates in the peritoneal cavity, a ventriculoatrial shunt terminates within the atrium of the heart, etc.