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RDSC 233 Unit 6 Radiography of the Excretory System Bontrager pp. 539-574 & Patient Care in...
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Transcript of RDSC 233 Unit 6 Radiography of the Excretory System Bontrager pp. 539-574 & Patient Care in...
RDSC 233 Unit 6Radiography of the Excretory SystemBontrager pp. 539-574 & Patient Care in Radiography chap. 10.
Positioning of:
KUB scout LPO & RPO ObliquesCone down of kidneysPost void upright
Radiographic anatomy
Film Critique
Anatomy of the urinary system
Exposure Factors
Iodinated Contrast Media
The Intravenous urogram (IVU) procedure
Tomography Review
Atlas of Human Anatomy Second edition (313)
Need to know
Fibrous capsule
Upper & lower pole
Medial & lateral borders
Renal pelvis
Renal artery and vein
Ureter
Ureteropelvic junction (UPJ)(infundibulum)
Atlas of Human Anatomy Second edition (313)& Bontrager (543)
Need to knowCortex *
Renal pyramids (medulla) **
Renal papilla
Minor & major calyces (calices) s. calyx
* Glomerular and Bowman’s capsule, Glomerulus
** Loop of Henle, renal a & v, collecting tubule
Atlas of Human Anatomy Second edition (343)
Need to know
Body, fundus, & neck of bladder.Mucosal lining, submucosa, muscular& serous layers
Ureteral orifice at uereterovesicle junction
Internal urethral orifice
Urethra (female 4 cm)
Trigone of bladder
Prostrate, prostatic urethra & urethra (male 20 cm)
Bladder capacity: 250 cc urge to void 700 cc capacity
Female
Male
Atlas of Human Anatomy Second edition (248) Need to know
Relative position of
Kidneys to spine Lt. Upper pole, T11-12 interspace Rt. Lower pole, L3
Ureters (12”) & psoas muscles
Iliac crest and inferior poles
Lateral border isposterior to medial border
Superior pole is posterior to inferior pole
Superior pole is medial to inferior pole
Radiographic Anatomyof the urinary system
catheter
IVU Tomogram Right Renal ArteriogramCirculation of iodine contrast before the nephron phase (first appearance) of kidney in an IVU
cortex
renal pelvis
nephron “blush”
renal a.
Ureter major calyx
minor calyces
Ureteropelvic junction(infundibulum)
cortexRt iliac crest
Hilum *
medulla
Lower polert. kidney
Upper polert. kidney
* In middle of medial border, superimposed on psoas m.
IVU Tomogram, late nephron phase, collecting systembeginning to visualize
15 minute KUB with full bladder
Lateralborder
Contrast Agents
January 1896 – First contrast injected into the vascular system of an amputated hand.
1904 – First cystogram. Air (negative contrast) injected retrograde into bladder.
1906 – First retrograde uretrogram using opaque contrast.
1923 – First excretory urography, called a “special procedure” due to the risk associated with the toxic substances used.
1950s – Less toxic, Iodine preperations were introduced under the brand names of Hypaque, Conray, and Renografin.
1986 – Nonionic iodine contrast agents were introduced.
Iodine
Iodine: atomic number 53.
Essential for nutrition, abundant in thyroid.
Principle ingredient in the surgical scrub, betadine
Non-metallic, commonly found in salt water swamps or brackish waters,in grayish-black, lustrous plates or granules.
A halogen (group VII elements including fluorine, bromine, and chlorine), iodine readily binds to salt.
Original “ionic” iodine contrasts were bound to sodium or meglumine salt. When injected, the molecule begins to disassociate, releasing ionic particles (+ cation and - anion) at a concentration 4 to 8 times higher than the particle content of blood (Osmolality).
127 53
Characteristics of Ionic Contrast
Iodine concentration determines the radiopacity of the agent. Measured in %weight/volume. Ranges from 10 to 82, dependent on its use. Many products include the concentration of iodine salts in the brand name: Renografin-60, Hexabrix 76, Isovue-200 (20%). See appendix L in Patient Care in Radiography.
Water soluable. Unlike barium in suspension, iodine preparations must mix with blood.
Stable in solution. The iodine molecule must remain in solution. Productsthat do not meet this requirement are packages as a solute, and solvent.
Low viscosity. The thickness of an agent significantly affects the ease in which a bolus is injected, and the rate of drip infusion.
Low toxicity. Any preparation not natural to the body is toxic to some degree, as are natural substances given in excess. The goal of contrast media is to keep adverse reactions to a minimum.
Low osmolality. The number of particles in solution is the chief factor of toxicity.
The Osmotic Effect
1. As contrastis injectedosmolalityincreases
2. Blood entering the capillary bed ishypertonic to the fluid in the surrounding tissues.
3. Extravascular fluid crosses the semi-permeable membrane of the capillary to achieve isotonicity, causing hypervolemia
4. Fluid drawn from RBCs, causes sickling.
5. Epithelial cells lining the intimal wall are similarly effected, and can lead to inflammation and thrombophlebitis
6. Flexibility of vessels walls allow vasodilationto accomodate hypervolemia.
Nonionic, low-osmolality contrast agents (LOACs)Quickly became popular in the late 1980s
Nonionics do not disassociate into as many particles, and thereforecreate fewer ions, and less osmolality. The cost is much greater, but comes with the promise of fewer contrast reactions.
From Patient Care in Radiography,5th edition. pg.269.
Precautions for the administration of all contrast agents
* Check the date on the bottle, ensure correct contrast is chosen * Do not throw bottles away until after exam
Contraindications:
Glucophage – med for diabetes mellitus. When combined with contrast increases the risk of renal failure. Recommended to be withheld 48 hrs prior to and following contrast administration
Multiple myeloma - Malignancy of bone that leads to renal failure, and increases the risk of contrast reactions.
Azotemia (uremia)- High levels of nitrogen waste in blood. Laboratory tests BUN (blood urea nitrogen) should be 8 – 25 mg/100 ml. Another test for nitrogen waste, Creatinine levels, should be .6 to 1.5 mg/dl.
Contraindications continued:
Hypersensitivity to iodine Anuria – no excretion of urine Severe renal disease or failure
Congestive heart disease (CHF)
Sickle cell anemia Pheochromocytoma – tumor of the kidney
In certain cases, an IVU may be performed despite contraindications. Patients should be well hydrated to lessen the risks.
What to watch for
Reactions candevelop quickly,and patients should not beleft alone.
From Patient Care in Radiography,5th edition. pg.271.
Potential Contrast Reactions (and treatments for)
Though the incidence is lessened, reactions to nonionic contrast injections are the same as for ionic agents. Most reactions occur within 5 minutes of injection.Staying calm and reassuring is imperative to the patient’s well being.
Mild: metallic taste dizziness flushing (slow, deep breathing) diaphoresis nausea chills (blanket warmer) vomiting (emesis basin) vasovagal (fear of needles) Moderate: urticaria (benadryl) swelling of parotids facial edema transient bronchospasm transient hypotension delayed skin reaction (keep patients 20 min) headache tachycardia
Severe: prolonged hypotension/circulatory collapse (Adrenaline [epinephrine] improves cardiac output and relaxes bronchial smooth muscles).
pulmonary edema arrhythmias (Inderal) angina (nitroglycerine) convulsions severe bronchospasm (adrenaline) coma cardiac arrest (sodium bicarbonate) paralysis death
The IVU Procedure
Materialscontrast (amount dependent on body weight, typically around 100cc)syringesbutterfly needles (19 or 21 gauge)venipuncture arm boardalcohol wipes tourniquet
emesis basintowelsemergency drugs/crash cart
lead marker setcompression device10” x 12” & 14” x 17” cassettesgonadal shieldspositioning sponges
Venipuncture
Reactionsupplies
Filming
The IVU Procedure
Routines are determined by department protocol, but a typical sequence is:
1 min. nephrogram, or nephrotomograms (cone down 10” x 12”)5 min. supine KUB (or 10” x 12” cone down of kidneys)10 and/or 15 min. supine KUB20 min. LPO & RPO obliquesUpright postvoid
Because the time it takes for the kidney to excrete the contrast is integral to the diagnosis of function, the IVU exam is timed, and marked on every film.
Prior to injection a KUB (scout film) is taken to check for technique, the position of the kidneys for the cone down views, the success of the bowel prep, (which is similar to that of a barium enema), and to identify calcifications that might otherwise be obscured by the contrast.
A hypertensive IVU includes films (often tomograms) done at 1, 2, & 3 minutes, or even 30 second intervals. This study is done to determine if hypertension is caused by the kidneys secreting excess renin.
The IVU Procedure
The good news is...The scout film is exactly the same as a plain film KUB:
The obliques are like colon obliques, except 300, and they include the pubic symphysis (bladder) like a KUB.
The upright postvoid is like the upright abdomen, exceptit is centered like a KUB to also include the bladder.
The only unique film is the 10” x 12” cone down of the kidneys for the nephrogram, or more commonly, thetomograms.
Routine IVU PositioningPreparation
1. Evaluate the order
2. Greet the patient 3. Take History4. Have patient void What is pertinent Hx?
5. Remove jewelry, check attire, snaps, pins, NG tubes, etc.
6. Explain the exam in layman’s terms
7. Questions?
urinary tract infection, mass, oliguria,renovascular hypertension, renalcalculi, elevated creatinine or BUN,hematuria, bladder CA, prostateenlargement, trauma to kidneys, polycystic kidney, malrotation,ectopic kidney
8. Set technique before positioning
Centering the Kidneys on a 10” x 12”
Lt. Upper pole, T11-12 interspaceLt. Lower pole, L3 (crest is L4-L5 interspace)
CR midway between xiphoid tipand iliac crest.
Note proximity of the lower pole of the rt. kidney to the iliac crest.Sometimes it is a couple of inchesabove it, and sometimes it is even lower
Sponge, bighelp for IVUs
Note pyloric bulb
Linear tomography is routinely used in IVUs. Cut thickness is typically 1 cm. Three levels are required to demonstrate the entire kidney in focus.
fulcrum – Physical pivot point
objective (focal) plane – plane in spacethat corresponds to the fulcrum, where the x-ray pivots
cut level – distance from the image receptorto the objective plane
exposure angle (arc) – The distance the tubetravels, measured in degrees.
section (cut) thickness – the thickness of the anatomy being imaged that is in the focalplane, and thus in focus.
amplitude – the distance the tube travels duringits excursion through the exposure angle.Does not effect the cut thickness, only theexposure time.
Localizing the Kidneys (level) for Tomography
Divide the measurementof abdomen at the level ofthe kidneys by three. Startat that cut level and work up.
For example, a 27 cm patientwould have “tomos” at 9, 10,and 11 cm.
11 cm10 cm 9 cm
Critique criteria for tomographic series
1. The upper and lower poles of both kidneys must be included.
2. Between the three tomographic levels, each kidney should be in focus, in its entirety
11 cm10 cm 9 cm
11 cm10 cm 9 cm
11 cm10 cm 9 cm
Perfect
Lower pole not in focal plane(started to low)
Upper pole not in focal plane(started too high)
Various focal planes in different patients: Even more evident than the focus of the kidney, is the appearance of the vertebra. These are arranged posterior (1) to anterior (4).
1
4
3
2
LPO and RPO obliques
300 obliques are doneto lay the kidney of interestout in profile.
In an AP projection the hilum isangled anteriorly.
An LPO position best demonstrates the internal collecting system of the rt kidney
RightLeft
Right
Left
LPO positionNote that the spine is further fromthe left ureter than the right ureter
LPO and RPO obliques
An RPO is seen here.
Note the appearance of the ala of the ilium,and the lt. SI joint.
The left kidney is seen in a PA view, butits ureter may be obscured by the spine.
The right kidney is obliqued 600 to the film,but its ureter will be free of the spine, andif filled with contrast, well demonstrated.
The compression technique (not routine)
If the internal collecting systemempties too rapidly to be wellvisualized, the radiologist mayrequest ureteral compression to obstruct the flow ofcontrast to the bladder.
Compression is applied by wrapping a band around the abdomen, securing a set of inflatable balloons over the ureters, and applying enoughpressure to create an artificial hydronephrosis.
Balloons
Ureter
The compression technique:Equipment
Y Inflation bulb
Inflation ballons, placedon the abdomen, centered on the ureters.
Sponge, placed overthe balloons
Rigid plate (plexiglass) to apply equalized pressure on sponge
Retention band: wrapped around abdomen, secures the plate and spongeover the balloons.
The compression technique
There are usually two balloons, though some models have one that is the size of two. With either model the top ofthe balloons are placed at the level of the iliac crest, and close to touching atthe midline.
Bontragerp. 371.
Contraindications to compressioninclude recent surgery, known abdominal mass, renal calculi, andaortic aneurysm. A 15% trendelenburgis used instead.
The compression technique
The top of the balloons are placed at the iliac crest, close to touchingat midline. The sponge is positioned over the balloons and the plexiglass plate is centered over the sponge. The compression band secures all the parts and is fastened with velcro. The balloonsare blown up to compress the ureters.
Post void or upright post void
The postvoid is typically done as thelast film of a routine. It is a standard KUB. It is most often done supine,but may be prone.
In addition to the residual contrast that the recumbant film demonstrates,the upright position shows the change in position of the bladder and kidneys, organs that are most susceptable to ptosis
In addition to these routine viewscone down views of the bladderand obliques may be requested.They will be covered in the uniton cystography.
Exposure Factors Techniques for an IVU are the same as for plain films of the abdomen except it is especially important to keep the kVp low to enhance the k-shell characteristic of iodine as much
as possible. 70-75 kVp is recommended.
K Shell Binding Energy of 33 keVP
rob
abil
ity
of A
bso
rbti
on
keV
33 keV
MuscleBone
Iodine
32 keV34 keV
30.
31.
32.
34.
33.
35.
36. Name one consequence of the osmotic effect (1 EC)
37. Name a second consequence of the osmotic effect (1EC)
30. Cortex
31. Renal pyramids (medulla)
32. Minor calyces (calices)
34. Hilum
33. Upper polert. kidney
35. Lateralborder
36. Name one consequence of the osmotic effect (1 EC)
37. Name a second consequence of the osmotic effect (1EC)
The Osmotic Effect
1. As contrastis injectedosmolalityincreases
2. Blood entering the capillary bed ishypertonic to the fluid in the surrounding tissues.
3. Extravascular fluid crosses the semi-permeable membrane of the capillary to achieve isotonicity, causing hypervolemia
4. Fluid drawn from RBCs, causes sickling.
5. Epithelial cells lining the intimal wall are similarly effected, and can lead to inflammation and thrombophlebitis
6. Flexibility of vessels walls allow vasodilationto accomodate hypervolemia.