Is a fluoroscopic (FL) retrograde pyelogram (intraoperative imaging of the renal pelvis and ureters) of the Kidneys, Ureters, and Bladder (KUB) the same as a Computed Tomography (CT) KUB?

From the Guidelines

No, a FL retrograde pyelogram KUB is not the same as a CT KUB, as they are different imaging techniques used to evaluate the urinary system, with CT KUB providing more comprehensive anatomical information but involving higher radiation exposure. A retrograde pyelogram is a fluoroscopic procedure where contrast material is injected through the ureters via cystoscopy to visualize the collecting system of the kidneys, ureters, and bladder, as described in the study by Gupta et al 1. In contrast, a CT KUB (computed tomography of kidneys, ureters, and bladder) is a cross-sectional imaging technique that uses X-rays to create detailed three-dimensional images of the urinary tract without requiring contrast injection through the ureters. The choice between these imaging modalities depends on the clinical question being addressed, with CT KUB generally offering more detailed information but involving higher radiation exposure, as noted in the guidelines by Gupta et al 1. Some key differences between the two techniques include:

• The use of fluoroscopy in retrograde pyelogram, which provides real-time X-ray images, versus the cross-sectional imaging of CT KUB
• The injection of contrast material through the ureters in retrograde pyelogram, versus the use of intravenous contrast in CT KUB
• The ability of CT KUB to detect stones, masses, and other abnormalities that might not be visible on conventional X-rays or fluoroscopic studies, as discussed in the study by Gupta et al 1
• The higher radiation exposure associated with CT KUB, as noted in the guidelines by Gupta et al 1 In certain situations, such as in patients with compromised renal function or contraindications to MRI, the use of retrograde pyelograms (RPGs) in combination with MRI or non-contrast CT may provide sufficient information to guide clinical care, as suggested in the guidelines by the American Urological Association 1. However, the choice of imaging modality ultimately depends on the specific clinical question being addressed and the individual patient's circumstances, as emphasized in the study by Gupta et al 1. It is also worth noting that other imaging modalities, such as ultrasound and digital tomosynthesis, may also be used to evaluate the urinary system, as discussed in the study by Gupta et al 1. Ultimately, the decision to use a FL retrograde pyelogram KUB or a CT KUB should be based on the individual patient's needs and the clinical question being addressed, taking into account the advantages and limitations of each imaging modality, as noted in the guidelines by Gupta et al 1.

From the Research

Comparison of FL Retrograde Pyelogram KUB and CT KUB

• FL retrograde pyelogram KUB and CT KUB are two different imaging techniques used to visualize the urinary tract.
• A retrograde pyelogram is a procedure that involves introducing water-soluble contrast into the ureter and collecting system of the kidney under fluoroscopic guidance 2.
• CT KUB, on the other hand, is a computed tomography scan that uses X-rays to produce detailed images of the kidneys, ureters, and bladder.
• While both techniques can be used to diagnose urinary tract abnormalities, they have different indications and uses. Retrograde pyelogram is often used to evaluate ureteral injuries, obstruction, stones, or tumors, and to assist with stent placement or ureteroscopy 2.
• CT KUB is commonly used to evaluate kidney stones, urinary tract infections, and other abnormalities of the urinary tract.
• In some cases, retrograde pyelography can be used in conjunction with CT scans to provide more detailed information about the ureteropelvic junction or other areas of the urinary tract 3.
• However, the utility of retrograde pyelography in following up on incompletely opacified ureters on CT urography is relatively low, with a yield of abnormal findings of only 2.7% in one study 4.

Key Differences

• The main difference between FL retrograde pyelogram KUB and CT KUB is the method of contrast administration and the type of images produced.
• Retrograde pyelogram uses fluoroscopic guidance to introduce contrast into the ureter, while CT KUB uses X-rays to produce detailed images of the urinary tract.
• The choice of imaging technique depends on the specific clinical question and the patient's condition.

Clinical Applications

• Retrograde pyelogram is a useful tool for evaluating ureteral injuries, obstruction, stones, or tumors, and for assisting with stent placement or ureteroscopy 2.
• CT KUB is commonly used to evaluate kidney stones, urinary tract infections, and other abnormalities of the urinary tract.
• In some cases, a combination of both techniques may be used to provide more detailed information about the urinary tract 3.