The Urinary System

Chapter 18

9/12/09

Basic Anatomy

• Often called the excretory system

• Includes– Two kidneys– Two ureters– One urinary bladder– One urethra

Kidneys• 2 bean shaped bodies

situated behind peritoneum

• Asymmetrical - left is slightly longer and narrower than right

• Rt kidney slightly lower than Lt kidney

• Lie in an oblique plane (opposite si jt direction)

• Normally extend from T-12 to L3

Kidney Function

• Remove waste products from blood

• Maintain fluid and electrolyte balance

• Secrete substances that affect blood pressure

• Excrete 1 - 2 liters of urine/day

Kidneys (cont’d)

• Minor calyces unite to form major calyces

• Major calyces unite to form renal pelvis

• Renal pelvis then drains into ureters

• Hilum - longitudinal slit in medial border for transmission of blood vessels, nerves, lymphatic vessels, and ureter

Kidneys (cont’d)

• Each kidney has outer cortex and inner medulla

• Medulla contains collecting system

• Essential microscopic components of kidney called nephrons

Anatomy: Nephron

• Each kidney-contains about one million nephrons

• Each nepron consists of:Renal corpuscle-

Glomerular capsule (Bowman’s capsule)

Glomerulus

Renal tubule

Anatomy: Nephron

• Glomerulus - filter for blood, allows fine particles and water to pass into capsule

• Renal tubule is continuous with capsule– Proximal convoluted tubule– Nephron loop (loop of

Henle)– Distal convoluted tubule

• Distal convoluted tubule opens into collecting ducts

Nepron (cont’d)

Continuous with collecting ducts which drain into minor calyx

Adrenal Glands

Cannot be seen on plain radiographs

Not part of urinary system

Chiefly responsible for regulating stress response through synthesis of corticosteroids and catecholamines, including cortisol and adrenaline

Ureters

• Two tubes 10 - 12 “ long

• Retroperitoneal• Extend from renal

pelvis• Enter bladder at ureteral

orifice

• Use peristalsis

Urinary Bladder

• Musculomembranous sac situated immediately posterior and superior to symphysis pubis of pelvis

• Serves as Urine reservoir

Urinary Bladder

• Bladder holds up to 500 mL of fluid

• Urethral orifice located in bladder neck

• Area between ureteral openings and urethral orifices is trigone

Urethra

• Carries urine from bladder to exterior of body

• About 1.5 long in females

• About 7 to 8 long in males

• Sphincter at neck of bladder

• Male urethra contains following parts:– Prostate– Membranous area– Spongy area

Prostate

• Gland surrounding proximal part of male urethra

• Considered part of male reproductive system, but due to location, often described with urinary system

• Prostate secretes fluid that mixes with seminal fluid

Radiography Of Urinary System

IVU- Intravenous Urogram !

Formerly erroneously known as IVP-Intravenous pyelogram!

– pyelo refers to renal pelvis and calyces only

– study also shows ureters, bladder, and sometimes urethra

Indications For Urography

• Demonstrate physiologic function and structure of urinary system

• Evaluate abd. Masses, renal cysts and tumors• Urolithiasis (stones)

• Pyelonephritis (Inflammation of kidney)

• Hydronephrosis (distension of renal pelvis and calyces with urine)

• Effects of trauma• Pre-op evaluation• Renal hypertension

Contraindications

• Inability to filter contrast medium from blood

• Allergy to contrast

• Abnormal BUN and Creatinine levels

Preparation Of Pt

• Pt should follow low residue diet for 1-2 days prior to exam

• laxative should be taken day prior to clean out bowel

• NPO after midnight• Pts with multiple myeloma, high uric acid levels,

or diabetes should be well hydrated before IVP exam– Dehydration leads to increased risk of renal

failure

Contrast Media

• Must be used to visualize urinary tract adequately

• Iodinated, water-soluble contrast administered intravenously to examine system

• Antegrade filling

Contrast Media

• Excretory urography (IVU) generally uses a 50 to 70% iodine solution

• Lower concentrations required for bladder studies due to large amount required to fill bladder (30%)

• Non-ionic contrast is generally used– More expensive– Patients less likely to have reactions with nonionic

Contrast Media and Adverse Reactions

• Crucial not to leave pt alone for first 5 minutes after injection!

• Mild reactions– warmth– flushing– hives, Nausea/Vomiting, respiratory edema

(accumulation of fluid in lungs)

• Severe reactions– Anaphylactic shock (sudden allergic response associated with a

sudden drop in blood pressure and difficulty breathing). Can lead to death in a matter of minutes)

Injection Procedure

• Obtain allergy history

• Explain exam to pt• Prepare contrast and supplies (sterile tech.)

• Assist radiologist as necessary– or

• Perform injection if IVcertified

Injection Supplies (cont.d)

• Tourniquet• IV arm board• Towels• Emergency kit• Emesis basin• Alcohol wipes, hibiclens, or povidone

iodine wipes or swabs

Injection Supplies

– 16 - 18 G needle for drawing up contrast

– Contrast

– 19 - 22 G needle, butterfly or angiocath for infusion

– Extension tubing

– Tape or clear-type dressing

IVU Procedure

• Pad on table• Place pad or pillow under pt’s knees• Scout - KUB• Contrast is injected• Timed sequence of films obtained until bladder

begins to fill• Immediate film of kidneys• 5 minute film of abd. or kidneys• Compression applied

Ureteral Compression

• Applied over distal ends of ureters

• Inhibits flow of urine into bladder

• Distends renal pelvis and calyces

• Compression device should be centered at ASIS

Ureteral Compression (cont’d)

• As much compression as pt can tolerate!

• Should not be applied when:– stones, abd. mass or

aneurysm, colostomy, suprapubic catheter, recent abd. surgery or trauma

• (Because of improvement of contrast agents, compression no longer generally used)

IVU Procedure cont’d

• Tomograms are obtained once bladder is filled

– Pt is measured, divide number by 3, cuts begin there

• Pt. measures 30cm, beginning cuts at 10cm

• Release compression slowly• Have pt void, and obtain

post-void film

Radiation Protection

• Radiographer is responsible!

• Gonadal shield - if it does not interfere with examination objective

• Close collimation

• Avoid repeat exposures

• Shield males for all urinary studies, except when urethra is of primary interest

Radiation Protection

• Shield females when IR centered over kidneys

• Rule out chance of pregnancy before examination– Emergency cases may not allow time

Radiographic Positions IVU

AP Projection-IVU

• Patient supine • Center MSP to film• CR to level of iliac

crest• Use shielding• (All exposures at end

of expiration for any urinary system study)

AP Projection- IVU (cont’d)

Must include entire KUB region

Should include prostatic region on older males

Time Delay - IVU

3 minute6 minutes

Time delay- IVU

9 minutesWith compression

AP Projection Variations

• Trendelenberg– Lower head 15 - 20 degrees– Helps demonstrate lower ureters

• Upright– Center lower - organs change position

• Prone– Demonstrates ureteropelvic region

– Fills obstructed ureter in cases of hydronephrosis (distension of renal pelvis and calyces with urine)

AP Oblique Projections - RPO/LPO

• Patient is supine• Patient rotated to

30 degrees• CR to iliac crest, 2

in. lateral to midline – Center to side up

AP Oblique Projections - RPO/LPO

• Elevated kidney will be parallel to cassette

• Kidney closest to cassette will be perpendicular

• Entire KUB region must be included

Nephrotomography

• Best method for visualizing renal parenchyma (neprons and collecting tubules)

• Ability to visualize kidneys free of intestinal content superimposition

Retrograde Urography

Retrograde Urography (cont’d)

• Considered an operative procedure

• Pt may be under general anesthesia

• Sterile technique is used

• Nurse responsible for set-up of exam and pt. care

Retrograde Urography

• Requires catheterization of ureters

• Contrast injected directly into pelvicaliceal system via cathethers

• Provides improved opacification of renal collecting system

Retrograde Urography (cont’d)

• Contrast does not enter blood stream

• For patients with renal insufficiency or contrast sensitivity

• Ureters, and collecting systems can be selectively imaged and sampled

• Little physiologic information provided

Cystography

Cystography

• Radiologic exam of urinary bladder

• Contrast administration usually performed retrograde (against normal flow of urine)

Excretory Cystogram Retrograde Cystogram

Cystography

Indicated for:

Vesicoureteral reflux (backward flow of urine into ureters)

Recurrent lower urinary tract infection

Neurogenic bladder: (dysfunction due to disease of central nervous system or peripheral nerves)

Cystography indications cont’d

– Bladder trauma

– Prostate enlargement

– Lower urinary tract fistulae

– Urethral stricture

– Posterior urethral valves (obstructive congenital defect of the male urethra)

Cystography

• Contraindications – anything related to catheterization of urethra!

“Retrograde” Cystography

• Contrast will be drip-infused via a catheter

• Bladder will be filled to capacity

• Fluoro-spot and overhead films will be obtained

Scout

filled AP

both obliques

lateral

voiding

post-void

Cystography Routine Series

AP Axial Bladder

• CR( similar to coccyx projection)

– Angled 10 to 15 degrees caudad to center of IR

– Enters 2 above upper border of pubic symphysis

AP Axial Bladder (excretory method)

PA Axial Bladder(prone)

CR– Angled 10 to 15 degrees cephalad

– Enters about 1”distal to coccyx

– Exits just above superior border of pubic symphysisPatient prone

– Arms out of anatomy of interest

– IR centered to CR

AP Oblique Bladder

• Pt position

– 40- to 60-degree

– RPO or LPO depending on physician preference

AP Oblique Bladder

CR– Perpendicular to center of

IR– CR 2 above the upper

border of pubic symphysis and 2 medial to upper ASIS

– If bladder neck and proximal urethra is of interest, 10-degree caudal angle of CR will project pubic bones below them

Lateral Bladder

• Patient position– Lateral recumbent,

right or left side

• Part position– Knees flexed – MCP aligned to

midline

• CR to midcoronal plane at 2 in. above symphysis pubis

Lateral Bladder

– Demonstrates anterior/posterior bladder walls

– Base of bladder– Any vesicovaginal

or vesicorectal fistulae

Cystourethrography

Cystourethrography

• Retrograde study to visualize bladder and urethra

• Contrast does not enter blood stream

• Sterile technique must be used

• Nurse will generally perform catheterization

Male Cystourethrography

• AP Oblique Projection - RPO/LPO

• Patient is supine, rotated 35 - 40 degrees

• Urethral syringe or Brodney clamp? is used to introduce contrast

Cunningham Penile Clamp: device used to help control male urinary incontinence.

Male Cystourethrography

• Images are obtained as contrast is injected

• Entire urethra must be visualized

• Bladder can be filled to obtain antegrade voiding study

• Why is this antegrade if its injected into urethra?

Female Cystourethrography

• Retrograde• AP Projection (maybe obliques)

• Bladder can be filled and patient void for antegrade studies

• Cassette should be centered as for cystography

• Abduct thighs to prevent superimposition of bone or soft tissue

Incontinence Studies

• Positioning is same as retrograde cystography

• On lateral films, pt. asked to strain to demonstrate any prolapse or incontinence

Metallic Bead Chain Cystourethrography

• To evaluate stress incontinence in females only

• Beaded chain inserted in Urethra

• Shows anatomic changes in shape and position of anatomic floor

• Valsalva tech. applied for comparison

Voiding Cystourethrogram

X-ray images of bladder and urethra during urination

Follows cystogram - urinary catheter removed

Pt. urinates into special radiolucent urinal as images taken

.

Voiding Cystourethrogram cont’d

• Shows size and shape of bladder under stress caused by urination

• Demonstrates urethra functioning

• Most commonly used for young girls with history of recurrent bladder infections

The End