The Urinary Tract - Srinakharinwirot...

Review anatomy of the urinary

tract

Imaging modalities

Contents

The Urinary Tract

Kidneys

ต าแหน่งไต

(position)

อยู่ใน retroperitoneum ระดับ T12-L3 โดยไต

ขวาจะมีระดับต ากว่าไตซ้ายเล็กน้อย

รปูรา่ง (shape) คล้ายรูปถั ว ด้านเว้าหันเข้าทาง medial

ทิศทางการวางตวั

(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 Parenchyma

Renal Sinus

Associations

Renal Vessels

Film KUB

IVP/IVU

IVP5 MINS

Ultrasound

ComputedTomography

(CT scan)

Magnetic resonance imaging (MRI)

Ureters

Film KUB IVP 10 Minutes

Physiologic narrowing of ureterI. Ureteropelvic junction (UPJ)

II. Distal ureter that cross bifurcation of iliac vessels

III. Ureterovesical junction (UVJ)

Physiologic Narrowing (1)

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:KidneysPsoas musclesUterus BladderLiver Spleen

1. Position2. Shape3. Axis 4. Size5. Cortical thickness6. Outline



Retroperitoneal mass?

Right psoasabscess

Intraperitonealmass

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. SpineII. Lower ribsIII. SacrumIV. PelvisV. 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 cause2. Urethra cause

Filling Defects

30 min: Full bladder

1. Size

2. Shape

3. Position

4. Architecture5. Density

Irregular bladder outline

Multiple bladder

diverticulum

Bladder

trabeculation

Bladder filling defects

Post voiding film

1. Residual urine

2. Small tumor3. 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

abnormality2. 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)

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. Hepatorenalpouch

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: medullatriangular-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

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

Renogram

Summary

Normal radiographic anatomy

Kidney, Ureter, Bladder, urethra

Investigation of the KUB system

Indication

Contraindication

Complication

Interpretation

Thank You

The Urinary Tract - Srinakharinwirot...

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