The Urinary Tract

 Review anatomy of the urinary tract

 Imaging modalities

Contents

The Urinary Tract

Kidneys

ต าแหน่งไต

(position)

อยู่ใน retroperitoneum ระดับ T12-L3 โดยไต ขวาจะมีระดับต ากว่าไตซ้ายเล็กน้อย

รูปร่าง (shape) คล้ายรูปถั ว ด้านเว้าหันเข้าทาง medial ทิศทางการวางตัว

(axis)

Long axis ของไตเอียงขนานไปกับเงาของ psoas muscle

ขนาด (size) ยาวประมาณ 10-16 cm. กว้าง 6 cm. หนา 4 cm. หรือประมาณ 3-4 lumbar vertebral

bodies ขนาดของไตสองข้างต่างกันได้ไม่เกิน 1.5 cm.

ความหนาของ renal cortex (cortical

thickness)

ประมาณ 1.5-2 cm.

ขอบ (outline) ขอบเรียบเสมอกัน

Kidneys

1. Renal capsule

 Gerota’s capsule

 Adipose capsule

 Fibrous capsule

2. Renal parenchyma

 Cortex

 Medulla

3. Renal sinus

 Renal pelvis

 Artery, vein lymph, nerves

 Fat

Renal Capsule

Renal capsule: 3 layers

I. Gerota’s capsule

II. Adipose capsule

III. Fibrous capsule

Renal Capsule

Renal capsule: 3 layers

I. Gerota’s capsule

II. Adipose capsule

III. Fibrous capsule

Renal Capsule

Renal capsule: 3 layers

I. Gerota’s capsule

II. Adipose capsule

III. Fibrous capsule

Renal Parenchyma

Renal Sinus

Associations

Renal Vessels

Film KUB

IVP/IVU

IVP

5 MINS

Ultrasound

Computed

Tomography

(CT scan)

Magnetic resonance imaging (MRI)

Ureters

Ureters

Film KUB IVP 10 Minutes

Physiologic narrowing of ureter

I. Ureteropelvic junction (UPJ)

II. Distal ureter that cross bifurcation of iliac vessels III. Ureterovesical junction (UVJ)

Physiologic Narrowing (1)

Physiologic Narrowing (2)

Physiologic Narrowing (3)

Urinary Bladder

Urinary Bladder

Urinary Bladder

Urethra

Urethra

♂ ♀

Urethra

Normal male urethrogram

Investigations

1. Plain KUB

2. Intravenous pyelography (IVP)

3. Retrograde pyelography (RP)

4. Cystography

5. Voiding cystourethrography (VCUG)

6. Ultrasonography

7. CT scan

8. Magnetic resonance imaging

9. Renal angiogram

10. Renogram

Plain KUB

Plain KUB

1. Soft tissue shadow

2. Abnormal calcification

3. Free air or free fluid

4. Bony structure

Soft tissue shadows:

Kidneys

Psoas muscles

Uterus

Bladder

Liver

Spleen

1. Position 2. Shape 3. Axis 4. Size

5. Cortical thickness 6. Outline

Soft tissue shadows:

Kidneys

Psoas muscles

Uterus

Bladder

Liver

Spleen

Soft tissue shadows:

Kidneys

Psoas muscles

Uterus

Bladder

Liver

Spleen

Soft tissue shadows:

Kidneys

Psoas muscles

Uterus

Bladder

Liver

Spleen

Retroperitoneal

mass?

Right psoas

abscess

Intraperitoneal

mass

DDx.- Urinary tract stone - Calcified granuloma - Tumor

- Gallstone

- Appendicolith - Costochondral

calcification

- Atherosclerosis - Phlebolith

- Prostatic calculi - Calcified uterine

fibroid

?

?

Example:

There is an oval-

shaped calcification at left L1-L2

paravertebral level, overriding lateral

margin of left psoas muscle. These

findings are suspected

of left UPJ stone.

UPJ stone

Calyceal stone

Staghorn stone

Emphysematous pyelonephritis

I. Spine

II. Lower ribs III. Sacrum

IV. Pelvis

V. Hip & SI joints Look for…

- Fracture

- Congenital bony defect

- Bony destruction

สรุป: การอ่าน Plain KUB

1. Soft tissue shadow

2. Abnormal calcification

3. Free air or free fluid

4. Bony structure

Intravenous Pyelography

(IVP)

IVP

*** Intravenous injection of iodinated contrast medium to evaluate for renal anatomy and function

1.

Standard IVP (50 mL contrast medium)

2.

Double dose IVP (100 mL contrast medium)

Factors

1.

Kidney function  GFR

2.

Intrarenal concentration:

 State of hydration, osmotic diuresis

3.

Exit of contrast from kidney (collecting system dynamics):

 Rate of urine flow, volume of collecting system, ureteral dynamics

IVP: Preparation

 Fluid restriction

 Increase visualization of contrast media

 Except for patients with poor renal function, DM, multiple myeloma, trauma, young child

 Bowel preparation

 To clear fecal content

 Not absolutely needed

IVP: Contraindication

1. Allergy to iodinated contrast media

2. Renal insufficiency (Creatinine Clearance < 30)

… Pregnancy

Note: Cr Clearance = (140-age)xBW(kg) 72xserum Cr (mg/dl) If female (x0.85)

IVP: Evaluation

3 min.

5 min.

10 min.

30 min, full bladder

Post void

Scout Film

Normal Nephrogram

3 min.

3 min: Nephrogram 1. Position

2. Shape 3. Axis 4. Size

5. Cortical thickness

6. Outline

Normal Excretion

5 min.

3 min.

5 min: Excretion

1. Minor/major calyx 2. Renal pelvis

Abnormalities

- Clubbing calyx/

hydronephrosis - Filling defect - Anomaly

- Dense nephrogram

10 min: Pelvocalyeal system and ureter

5

Scout film

3 mins

5 mins

10 mins Findings of UPJ

obstruction

Scout 5 min

10 min

Hydronephrosis

Double collecting system

10 mins 30 mins

scout 10 mins post void

Right UVJ stone causing obstruction

Bilateral

hydronephrosis &

hydroureters 1. Bladder cause

2. Urethra cause

Filling Defects

30 min: Full bladder 1. Size

2. Shape 3. Position

4. Architecture

5. Density

Irregular bladder outline

Multiple bladder

diverticulum Bladder

trabeculation

Bladder filling defects

Post voiding film

1. Residual urine

2. Small tumor

3. Small stone

IVP: Indication

1. Renal and ureteric calculi

2. Colicky abdominal pain

3. Persistent or frank hematuria

4. Complicated urinary tract infection

5. Urothelial tumors

6. Abnormal US or renogram

IVP

1. Unable to identify renal parenchymal abnormality

2. Need IV contrast  renal failure 1. Can evaluate renal function

2. Can demonstrate urothelium

3. Can visualize the ureter

Retrograde Pyelography

(RP)

Retrograde Pyelography (RP)

RP: Indication

1. Poor kidney excretion

2. Evaluate pelvocalyceal system if uncertainty from IVP

3. Unexplained hematuria

RP: Contraindication

1. Urinary tract infection

RP: Complication

1. Infection

2. Trauma to urethra

Cystography

Retrograde Cystography

Cystography: Indication

1. Evaluate size and contour of urinary bladder

2. Bladder carcinoma

3. Trauma: rupture bladder

4. Low-pressure vesicoureteral reflux

5. Vesical fistula

Voiding Cystourethrography

(VCUG)

Voiding Cystourethrography

(VCUG)

VCUG: Indication

1. Urinary tract infection in children:

- Urethral abnormality: posterior urethral valve

- Vesicoureteral reflux (VUR

)

2. Cause of urinary incontinence

1. Descending (antegrade) urethrography

2. Ascending (retrograde) urethrography

Urethrography

Descending Urethrography

 Urethrography was performed during voiding

Ascending/Retrograde Urethrography

Urethral stricture at

bulbous portion

Urethrograpy: Indication

1. Urethral trauma

2. Urethral stricture or anomaly

Ultrasonography

(US)

Longitudinal scan of right

kidney

1. Liver

2. Right kidney 3. Right

diaphragm 4. Hepatorenal

pouch

Normal kidney

Normal renal parenchyma,

slightly hypoechoic

Liver parenchyma

Hepatorenal pouch, no free fluid

Normal renal fat = hyperechoic No dilatation of collecting system

Normal renal pyramids: medulla

triangular-shaped, hypoechoic structures

Renal parenchymal disease

Increased renal echogenicity Normal kidney

Obstruction  hydronephrosis

Compressed renal fat, hyperechoic

Renal parenchyma,

hypoechoic Dilated collecting

system, anechoic (fluid)

Renal mass: solid / cystic

Bladder, uterus, prostate gland

US: Indication

1.

Renal mass

2.

Creatinine rising

 Renal disease or obstruction 3.

Infection of kidney

 Renal abscess, perinephric abscess 4.

Renal transplant patients

5.

Urinary bladder lesion

6.

Renal biopsy

US-KUB

1. Cannot evaluate renal function 2. Limit evaluation of ureter

3. Operator dependent 1. No radiation

2. Can be used in pts with renal failure 3. No need to NPO

4. Image guided biopsy

Computed Tomography

(CT KUB)

CT Renal Protocol

I.

Precontrast phase

II.

Corticomedullary phase (30-60 sec)

III.

Nephrographic phase (60-100 sec)

IV.

Excretory or delayed phase (180-300 sec)

 Non contrast

 Corticomedullary phase

 Nephrographic phase

 Excretory phase

 Ureter

 Ureter

 Ureter

 Ureter

 Ureter

 Ureter

 Bladder

CT: Indication

1. Renal mass: diagnosis, staging

2. Tumor of urinary system

3. Renal trauma

4. Infection

5. Renal artery stenosis

6. Renal stone protocol

CT KUB

1. Radiation

2. Contrast administration

1. Can evaluate renal function and anatomy

2. Good detail study

Magnetic Resonance Imaging

(MRI)

Magnetic Resonance Imaging (MRI)

MRI

1. Long scan time

2. Metallic / motion artifact

3. Not sensitive for stone or calcification 4. Expensive

1. No radiation

2. Risk of Gadolinium allergy < iodinated CM

3. Good for evaluating renal artery stenosis

Renal Angiography

Renal Angiography

Renogram

Renogram

Summary

 Normal radiographic anatomy

 Kidney, Ureter, Bladder, urethra

 Investigation of the KUB system

 Indication

 Contraindication

 Complication

 Interpretation

Thank You