Chapter 14 Urinary System & Venipuncture - Lesson 4 (pgs. 547-561)
What are the two primary purposes of an IVU?
1. Visualize the collecting portion of the urinary system 2. Assess the functional ability of the kidneys (timed procedure)
How many degrees is the head end of the table lowered for the trendeleburg position?
15 degrees
What is retrograde cystography commonly used to rule out?
- Trauma - Calculi - Tumor - Inflammatory disease of urinary bladder
What are two reasons for voiding right before the exam?
1) A bladder that is too full could rupture, especially if compression is applied early in the examination 2) Urine already present in the bladder dilutes the contrast media that accumulates there
What are the routine projections for an IVU?
1) AP scout 2) Nephrotomography (1 min following injection) 3) AP 4) RPO & LPO 5) AP postvoid (recumbent or erect)
What are 6 contradictions to ureteric compression?
1) Abdominal mass 2) Possible ureteric stones 3) Abdominal aortic aneurysm 4) Recent abdominal surgery 5) Severe abdominal pain 6) Acute abdominal trauma
What are some common clinical indications in which an IVU would be utilized?
1) Abdominal or pelvic mass 2) Renal or urethral calculi 3) Kidney trauma 4) Flank pain 5) Hematuria 6) Hypertension 7) Renal failure 8)Urinary tract infection (UTI/pyelonephritis)
What radiographic equipment & supplies are needed for urography (examples)?
1) Correct type & amount of contrast media drawn up in appropriate syringe 2) Empty container of contrast media in visible sight 3) Selection of sterile needle/access to sharps container 4) Alcohol sponges & wipes 5) Clean procedure gloves and tourniquet 6) Towel or sponge to support the elbow 7) Male gonadal shield 8) Emesis basin 9) Lead numbers, multiple marker, R & L markers 10) Epinephrine or Benadryl ready for emergency injection 11) Ureteric compression device ( if used by dept.) 12) Cold towel for forehead and/or injection site (warm towel) 13) Operational & accessible oxygen & suction devices
What are the benefits of Magnetic Resonance Imaging (MRI) for renal/urinary studies?
1) Demonstrates subtle tissue changes in urinary bladder & kidney 2) Evaluates tumors, renal transplants, and patency of renal artery & vein 3) Coronal sagittal & transverse perspectives of urinary system (can provide means of determining the spread of select tumors of the kidney to adjacent structures) 4) T1-weighted images show the kidney well defined in contrast to fat-laden peri-renal space.
What are the benefits of Sonography (US) for renal/urinary studies?
1) Evaluates kidney & bladder in a noninvasive manner 2) Filled bladder demonstrates bladder calculi or masses in bladder & organs surrounding the bladder 3) Evaluates kidney to determine whether cysts or masses are 4) Can measure parenchymal perfusion, along with Nuclear Medicine
What are some general patient preparation steps for an IVU?
1) Light evening meal before the procedure 2) Bowel-cleansing laxative 3) NPO after midnight (minimum of 8 hrs.) 4) Enema on the morning of the exam
What medications are contraindicators for urographic procedures and must be checked prior to the exam?
1) Metformin (glucophage) 2) Glucotrol 3) Avandamet 4) Glucovance 5) Diofen 6) Fortamet 7) Riomet 8) Actoplus Met Diobex 9) Metaglip
What are the benefits of CT renal studies?
1) Minimal bowel prep: Water only at least 1 hour prior to procedure 2) Noncontrast images to evaluate for presence and location of renal calculi 3) Option to use contrast media provides a structural and functional study 4) Fast procedure with helical CT scanner Image reconstruction capability
What are the steps used for ureteric compression?
1) Place deflated paddles over outer pelvic brim before contrast injected (compresses ureters) 2) The inner edges should almost touch on each side of spine 3) Greatest pressure at point where ureters cross psoas muscles (center of inflated paddles) 4) Inflate paddles once contrast is introduced & keep in place until post compression images are taken.
What are 3 common variations to the routine IVU?
1) Postrelease or "Spill" procedure with ureteric compression 2) Erect position for bladder 3) Delayed radiographs
What should the patient do just prior to the IVU exam?
1) Remove all clothing except socks/shoes 2) Put on hospital gown with opening in back 3) Void
What is routine procedure for retrograde urography?
1) Scout radiograph taken 2) Series of radiographs taken as requested 3) Uretogram taken once catheter has been removed
What are the benefits of Nuclear Medicine for renal/urinary studies?
1) Specific procedures can measure renal function & excretion rates. 2) Provides a functional evaluation of the kidneys 3) Provides a less hazardous method of evaluating the kidneys for signs of chronic or acute renal failure without use of iodinated contrast media 4) Radionuclides used to determine existence of physical blockage in ureters & evaluation of vesicoureteral reflux (trace reflux can be tracked & filmed due to filling of small amount of radionuclide and saline in the bladder)
Why is an IVU scout image taken?
1) To verify patient preparation 2)To determine whether exposure factors are acceptable 3) To verify positioning 4) To detect any abnormal calcifications
What is a postrelease or "Spill" procedure with ureteric compression?
A full size image taken after compression is release to assess for asymmetric renal function (may be applied immediately after 5-min image & removed immediately before 15-min image)
What is retrograde urography?
A nonfunctional exam of the urinary system (Normal physiologic processes are not involved)
What are the Special IVU projections?
AP ureteric compress & PA prone position
What projections are commonly used for a retrograde cystography procedure during fluoro?
AP w/15º caudad angle and bilat. posterior oblique projections
What are the types/gauges of needles commonly used for IVU exams?
Butterfly and over-the-needle catheter; 18, 20 and 22 gauges
What is performed in place of an IVU when the patient's BUN/Creatinine levels are not in normal ranges?
CT renal study; normal levels - BUN 8-25 mg/100 mL & Creatinine 0.6-1.5 mg/mL
What is modality is highly effective for imaging the prostate?
Endorectal ultrasound; can be used to distinguish between solid, cystic and mixed tissue masses in the prostate gland
T/F: Children are NOT sensitive to changes in diet, fluid intake & iodinated contrast media.
False; restricting fluids for extended time can cause dehydration (can lead to added risk for contrast media reaction)
What is voiding cystourethrography (VCU)?
Functional study of the bladder and urethra performed after routine cystogram (evaluates the ability to urinate - the catheter is removed and imaged while voiding)
What is the correct term for excretory urography?
IVU - intravenous urogram; radiographic examination of the urinary system
What is the purpose of a Hypertensive Intravenous Urogram?
IVU for patients with high blood pressure (determines whether the kidneys are the cause of the high blood pressure)
If a patient is scheduled for an IVU & BE on the same day, which exam should be performed first?
IVU; if the BE is performed first there will already be contrast in the area of the kidneys
When is retrograde urography performed?
In surgery to determine location of urinary calculi or other obstruction; in which contrast media is delivered retrograde through a catheter
How do you set the fulcrum (focal plane) level for a nephrotomogram?
Measure thickness of midabdomen in cm using calipers; once obtained, divide it x 3 (Ex. An abdomen measuring 24 cm thick, 1st set the fulcrum at 8 cm (24/3=8))
What is retrograde cystography?
Nonfunctional radiographic exam of the urinary bladder performed after instillation of iodinated contrast media through a ureteral catheter
What is retrograde urethrography?
Nonfunctional radiographic study of the male urethra to demonstrate the full length of urethra, trauma and obstruction of urethra (rarely performed)
What are nephrograms/nephrotomogram?
Radiographs taken early in study to demonstrate renal parenchyma or functional portion of kidney during nephron phase (contrast dispersed through microscopic nephrons, not yet in collecting tubules
What is the suggested protocol for a hypertensive intravenous urogram?
Radiographs taken every minute, up to 5 minutes with lead numbers (at least 1, 2 & 3 min); After 5-minute IR, standard IVU routine Check with radiologist to determine additional images to be taken
What are some digital considerations?
Similar to abdominal projections: 1) Close collimation 2) Accurate centering 3) Optimal exposure factors 4) Post-processing evaluation of exposure indicators
What is considered a safer alternative to pediatric urography ?
Sonography; IVU's prove to be a greater risk for children, technologists must monitor these patients carefully
What are the routine steps of an IVU exam?
Step 1) Scout radiograph Step 2) Injection (note time at beginning of injection) Step 3) Sample imaging routine: A. Immediate (1 min after start of injection) nephrogram or nephrotomography B. 5 min (following initial) AP supine KUB C. 10-15 min AP supine KUB D. 20 min posterior obliques (LPO & RPO-project ureters away from spine) E. Postvoid (prone or AP erect-include bladder)
When should an IVU scout image be taken?
Taken before injection along with patient history to show to the radiologist
T/F: Hypertensive intravenous urograms allows for a much shorter time between projections as compared with standard IVU.
True
T/F: The greater the tomographic angle, the thinner the section imaged.
True
T/F: When it comes to patient prep for an IVU, the patient must be free of gas/fecal matter.
True
T/F: The exact start time and length of injection should be noted for an IVU injection.
True, timing is based on the start of injection and usually takes between 30-60 secs to complete
How is the contrast media administered for retrograde urethrography?
Via retrograde route by use of Brodney clamp (attached to distal penis for contrast injection)
How is contrast media administered for retrograde cystography?
allowed to flow in through a catheter by gravity only; 150-500mL
When is the trendelenburg position utilized for a urographic procedure?
as an alternative to ureteric compression; trendelenburg provides some of the same results without as much risk when there are contradindications for ureteric compression
Delayed radiographs (alt. to IVU) may be:
brought back to dept. on a 1-2 hr basis for postvoid images in prone or upright position (emptying the bladder shows small abnormalities/upright demonstrates any unusual movement of kidneys)
How can the thickness of the tomographic section be changed?
by changing the tube angle (amplitude)
Why is a postvoid (post micturition) projection an essential part of an IVU?
can be helpful in demonstrating residual urine; this residual urine can be an indication of small tumor masses or possible enlargement of the prostate gland
How are nephrotomogram obtained?
during a nephron phase with 3 separate focal levels
What is the purpose of ureteric compression?
enhance filling of the pelvicalyceal system and proximal ureters (allows the renal collecting system to retain contrast media longer for a more complete study)
When should the exposure be made for a nephrotomogram?
exactly 60 sec. after start of injection; table, IR and control panel must be set before injection is initiated due to injection time
What is ESWL?
extracorporeal shock wave lithotripsy (ESWL), electrohydraulic shock waves (sound waves) used to break apart calcifications in the urinary system.
How is the patient positioned for a retrograde urethrogram?
in a 30 degree RPO position centering to symphysis pubis (urethra superimposed over soft tissues of right thigh)
Where is the CR for the nephrotomogram?
midway between iliac crest & xiphoid process
In what scenario should an IVU be performed on a pregnant female?
only when absolutely necessary and when the benefits exceed the risks (may be ordered to rule out urinary obstruction)
What is tomography?
procedure that uses reciprocal (back & forth/linear) motion between the x-ray tube and the film to image structures at a particular level in the body, while blurring everything above and below that level
What can an erect position for the bladder (alt. to IVU) be used to demonstrate?
prolapse of bladder or enlarged prostate (taken before voiding)
What is the best way to reduce dose to the fetus, in case of a pregnant patient?
reduce the number of projections taken and use higher kV with lower mAs
What is the primary purpose of tomography?
to display anatomy within the focal plane in focus; anatomy outside of fulcrum plane is mechanically blurred
What are VCU's useful for demonstrating?
trauma and incontinence
How are nephrograms usually acquired?
with a 1 min radiograph after start of injection
When do most adverse contrast reactions occur?
within the first five minutes following injection (must carefully observe patient for signs of reaction); note amount & type of contrast in chart
