Peritoneal Imaging

Various imaging techniques can be used to diagnose suspected dialysate leaks into the subcutaneous tissue, pleural cavity, retroperitoneal space, or the genitals. Computerized tomography (CT) imaging peritoneography, peritoneal scintigraphy, or magnetic resonance imaging (MRI) can be used to confirm abnormal dialysate locations.^{1, 2, 3} CT and scintigraphy involve the addition of either CT contrast material into the dialysate or a radioactive isotope. After injection of the contrast material or isotope into the dialysate and the dialysate is allowed to dwell, the radiographic images are obtained to assist in diagnosis. With MRI no contrast agent is required as the dialysate itself brightly enhances during MRI. This information is important in order to localize the leakage site and to assist the surgeon if surgical intervention is necessary. Peritoneal imaging can also be used to identify fluid loculation, a result of peritoneal adhesions.

Note: Communicate the purpose of the test to the radiologist and review radiographs personally. It is advisable to coordinate the diagnostic study with the PD nursing staff to perform the addition of the imaging marker to the dialysate and to make the tubing connections to prevent contamination of the catheter by healthcare personnel who may be unfamiliar with dialysis technique.

CT Peritoneography:¹

Procedure:

• Add 80 mL of water soluble contrast media (80 mL OMNIPAQUE 350) to 1.5 L of dialysis solution
• Infuse dialysis solution with radiocontrast into supine patient
• Instruct patient to move and walk to promote intraperitoneal mixing and to raise intra-abdominal pressure to drive the contrast into the source of the leak

If pleuroperitoneal fistula is suspected, CT should include the chest. If scrotal swelling has been noted, the examination should include this area, otherwise avoid radiation of the testes.

Peritoneal Scintigraphy:²

Procedure:

• Add 2 mCi of technetium-99m sulfur colloid to 2 L of dialysis solution
• Infuse radionucleotide-containing dialysate into supine patient with anterior dynamic images obtained at 1 frame per minute for 15 minutes
• Instruct patient to move and walk for 30–60 minutes to promote intraperitoneal mixing and to raise intra-abdominal pressure to drive the radiotracer into the source of the leak
• Obtain 5-minute postambulatory static images in anterior, posterior, and both lateral views
• Drain dialysate from peritoneal cavity and repeat 5-minute static images in anterior, posterior, and both lateral views

Include chest if pleuroperitoneal fistula is suspected. Include inguinal region if scrotal swelling has been noted.

Magnetic Resonance Imaging (MRI):³

No contrast is required. Patient is allowed to dwell the dialysate exchange while positioned in the MRI scanner. Images are obtained of suspected area of leakage using T2-weighted images.

References used in this Appendix section

1. Litherland J, Lupton EW, Ackrill PA, Venning M, Sambrook P. Computed tomographic peritoneography: CT manifestations in the investigation of leaks and abnormal collections in patients on CAPD. Nephrol Dial Transplant 1994;9(10):1449–52.
2. Juergensen PH, Rizvi H, Caride VJ, Kilger AS, Finkelstein FO. Value of scintigraphy in chronic peritoneal dialysis patients. Kidney Int 1999;55(3):1111–9.
3. Prischl FC, Muhr T, Seiringer EM, et al. Magnetic resonance imaging of the peritoneal cavity among peritoneal dialysis patients, using the dialysate as “contrast medium”. J Am Soc Nephrol 2002;13:197–203.