In this presentation, we’ll take a brief overview of the radiographic procedures of
the urinary system.
While some of these procedures are still done, CT has taken the reigns as the modality of
choice for urograms.
Intravenous Urography is ordered to Evaluate abdominal masses, renal cysts, and tumors.
Other things commonly visualized are Urolithiasis, or stones of the urinary tract or kidneys.
Pyelonephritis is infection of the upper urinary tract.
Hydronephrosis is an abnormal dilation of pelvicaliceal system.
Evaluation of trauma effects can be seen, and preoperative evaluation of function, location,
size, and shape of kidneys and ureters can be accomplished with IVU studies.
Renal hypertension can also be evaluated.
Contraindications for IVUs relate to the ability of the kidneys to filter contrast medium from
the blood and patient’s allergic history.
Some contraindications can be overcome by use of nonionic contrast.
High-risk patients may be evaluated with other modalities.
Risk factors include Asthma, Previous contrast reaction, Circulatory or cardiovascular disease,
Elevated creatinine level, Sickle cell disease, Diabetes mellitus, and Multiple myeloma.
Before procedure, patient must empty bladder, remove clothing, and put on a gown.
Review blood chemistry.
Glomerular filtration rate (GFR) is the best overall indicator of kidney function.
Normal GFR range is 120 to 125 mL/min.
90 mL/min = renal dysfunction.
Normal creatinine is 0.6 to 1.2 mg/100 mL.
Perform venipuncture, then administer 30 to 100 mL of contrast for adult patient of average
size – the radiologist should confirm the appropriate dosage after viewing recent lab
values.
Dosage for infants and children is adjusted according to age and weight
Produce radiographs at specified time intervals.
This is where the procedure varies according to department protocol.
The most common radiographs for IVU examinations are AP projections at time intervals ranging
from 3 to 20 minutes.
AP oblique projections in 30-degree posterior oblique positions often taken at 5- to 10-minute
intervals.
Unless bladder or voiding urethrograms are to be made, the patient is sent to restroom
to void.
A post-void radiograph of the bladder may be taken which is used to check for small
tumor masses or enlarged prostate in male patients.
After the procedure, the patient should be instructed to drink extra fluids to aid in
flushing contrast.
For the AP Urinary System view, perform this just as you would a KUB.
The patient position should be supine with support at knees to reduce back strain if
needed.
The MSP should be aligned to midline of grid device.
Move arms out of field and center IR to level of iliac crest.
Two IRs may be required to demonstrate all anatomy on tall patients.
The CR should be perpendicular to center of IR at level of iliac crests at the MSP.
The collimated field should be 14 x 17 inches (35 x 43 cm) and the exposure should be taken
on suspended expiration.
AP obliques are usually performed RPO and LPO.
The patient position remains supine with support on the elevated side.
The kidney closer to IR will be perpendicular to plane of IR, while the kidney farther from
IR will be parallel with IR.
Rotate so that midcoronal plane (MCP) forms 30-degree angle from IR.
Keep shoulders and hips in same plane with the MSP aligned to midline of grid device.
Move the arms out of field, and center IR to level of iliac crests.
The CR should enter approximately 2 inches (5 cm) lateral to midline on elevated side
at level of iliac crests with a collimated field of14 x 17 inches (35 x 43 cm).
Take note in these images of the RPO and LPO urinary system views allow for a profile view
of the kidney side-up, while freeing the ureter of the spine for clear visualization on the
side down.
Tomography is typically performed immediately after contrast administration.
This demonstrates renal parenchyma (nephrons and collecting tubes).
For tomograms, the x-ray tube and the bucky are in motion, creating a fulcrum where the
anatomy should be.
This blurs all anatomy above and below the focal point, and the technologist may take
several views, adjusting the focal point depth to provide multiple tomograms throughout the
kidney.
Again, this procedure is not very common anymore with the addition of CT, but these images
show the advantages of seeing the contrast-filled kidneys free of superimposition of the bowel,
ribs, and dense muscle tissue of the lower back.
You can tell the image on the left has a focal point that is more anterior than the image
on the right because the vertebral bodies are in focus, whereas the image on the right,
the lamina, spinous processes, and transverse processes can be seen more clearly.
Retrograde Urography requires catheterization of ureters, usually done by a Urologist with
the patient under anesthesia.
Contrast is injected directly into pelvicaliceal system and provides improved opacification
of renal collecting system.
Little physiologic information is provided, and this study may be indicated for evaluation
of collecting system in patients with renal insufficiency or contrast sensitivity since
this method of administration does not require injection into the bloodstream.
Retrograde Urography is classified as an operative procedure and is carried out under aseptic
conditions.
The image on the left shows the catheters in place bilaterally in the ureters, and on
the right, we see the full contrast injection.
Notice how the renal parenchyma does not highlight for retrograde studies as the contrast is
injected outside of the bloodstream.