RDSC 233 Unit 6 Radiography of the Excretory System Bontrager pp. 539-574 & Patient Care in Radiography chap. 10. Positioning of: KUB scout LPO & RPO Obliques.

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 Anatomy

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

AnatomyReview

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.

Informed Consent

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

Radiographic Positioning of the IVU

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.

StartVerticalFinish

VerticalStart Finish

Linear Tomography

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)

Focus is approximately

here

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

The End

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.