Presentation on common urinary system pathologies and radiological findings. Just a brief explanation. Further info can be obtained from www.radiopaedia.org and www.radiologyassistant.nl

1. URINARY SYSTEM – PATHOLOGICAL
CORRELATION
PREPARED BY DR CHIA KOK KING (MD)
HOSPITAL SULTANAH BAHIYAH
MMED RADIOLOGY (USM), PHASE I
SUPERVISOR : DR JUHARA HARON

2. OVERVIEW
Pathological correlation of altered radiological patterns in
urinary system
Changes in size, shape, number, and textures of normal
structures
Mass
Opacities, lucencies, and calcifications
Wall thickening

3. QUICK RECAP : ANATOMY OF KIDNEY
• Anteriorly
• Right – liver, 2nd part of duodenum, ascending colon, small bowel
• Left – stomach, pancreas, spleen, splenic flexure, jejunal loops
• Posteriorly
• Upper 1/3 – diaphragm, 12th rib, costodiaphragmatic recess of pleura
• Lower 1/3 – (medial to lateral) psoas, quadratus lumborum, transverse
abdominis muscles.
• Superiorly
• Adrenal gland – more medial on the right kidney
• Blood supply
Renal artery interlobar arteries arcuate arteries
interlobular arteries glomeruli (afferent efferent arterioles)

4. QUICK RECAP : ANATOMY OF URINARY BLADDER
• Pyramidal muscular organ (contracted)
• Ureters - posterolateral angle.
• Urethra exits inferiorly, surrounded by internal urethral
sphincter
• Bladder walls :
• 1 superior wall
• 2 inferolateral walls
• Trigone : triangular inner wall between urethral orifices
and urethral opening
• It is smooth.

5. QUICK RECAP : ANATOMY OF URETHRA
• Runs from internal urethral sphincter
at neck of bladder to external
urethral orifice at tip of penis.
• Anterior
• Penile
• Bulbous
• Posterior
• Prostatic
• Membranous
Female
• ~4cm long

6. DEVELOPMENTAL ANOMALIES OF KIDNEYS AND URETERS
• Number & size
• Renal agenesis
• Supernumerary kidney
• Dilatation (hydronephrosis)
• Polycystic kidney disease
• Fusion
• Horseshoe kidney - most common
• Cross fused renal ectopia
• Pancake kidney
• Location
• Pelvic kidney
• Cross lumbar renal ectopia
• Renal malrotation
• Nephroptosis (floating kidney)
• Shape
• Persistent fetal lobulation
• Hypertrophied column of Bertin
• Hilar lip
• Dromedary hump
• Vasculature
• Accessory renal arteries - commonly present in
~30% of patients
• Renal vein anomalies
• supernumerary renal veins
• Collecting system
• Duplex collection system - most common
(overall)
• Bifid collecting system
• Retrocaval ureter

7. CHRONIC KIDNEY DISEASE
• Progressive loss of glomerular function
• Due to renal parenchymal disease, most
commonly :-
 DM
 HPT
 Nephritis/nephrosis
 Polycystic kidney disease
• Present when eGFR ≤ 60 in 3 consecutive
months (from baseline).
• No specific imaging modality.
• No specific imaging modality
• Ultrasound renal Doppler examination
 reduced renal length
 reduced renal cortical thickness
 increased renal cortical echogenicity
 poor visibility of the renal pyramids and the renal
sinus
 marginal irregularities
 papillary calcifications
 cysts (acquired cystic kidney disease)
 reduced renal vascularity
 increased RI values (segmental and interlobular
arteries)

10. • 0 : Hypoechogenic than liver, maintained corticomedullary differentiation
• 1 : Isoechogenic as of liver, maintained corticomedullary differentiation
• 2 : Hyperechogenic greater than liver, with maintained corticomedullary differentiation
• 3 : Hyperechogenic than liver with poor corticomedullary differentiation
• 4 : Hyperechogenic than liver with loss corticomedullary differentiation
Grade 0 Grade 1
KIDNEY ECHOGENICITY - GRADING

11. Grade 3Grade 2
Grade 4

12. RENAL CYSTIC DISEASE
Developmental
Multicystic
dysplastic kidney
(MCDK)
Genetic
Autosomal
recessive
polycystic kidney
disease (ARPKD)
Autosomal
dominant
polycystic kidney
disease (ADPKD)
Juvenile
nephronophthisis
(JNPHP)
Medullary cystic
kidney disease
(MCKD)
Glomerulocystic
kidney disease
(GCKD)
Cysts associated
with systemic
disease
Von Hippel-Lindau
syndrome (VHLS)
Tuberous sclerosis
Acquired
Simple cysts
Acquired cystic
renal disease
Medullary sponge
kidney (MSK)
Malignancy
Cystic renal cell
carcinoma (RCC)

13. PATHOPHYSIOLOGY OF CYST DEVELOPMENT
• Develops from renal tubule
• Detach from parent tubule
after growing few mm in size
• Due to
• Increased proliferation of
tubular epithelium
• Abnormalities in tubular cilia
• Excessive fluid secretion

14. • “Simple” cysts :
• absence of internal echoes
• posterior enhancement
• round/oval shape
• sharp, thin posterior walls.
• Benign and no follow-up is required.
• US => limited information
• Only Bosniak I and Bosniak II cysts may be
followed up with US.
• “Complex” cysts are considered when :
• Cystic lesions (thickened/irregular
walls/septa) - suspicious
• Vascularity of the septa - suspicious
• These should raise the suspicion for renal
cell carcinoma.
RENAL CYSTIC DISEASE

15. BOSNIAK
CLASSIFICATION
• Based on findings of CT renal 4 phase
Simple cyst
Minimally
Complex
Minimally
Complex
(Follow up)
Indeterminate
Cystic
neoplasm /
Clearly
malignant

16. • 95% of IIF cysts are proven to be
nonmalignant.
• Any mass that enhances between
10 to 20 HU (i.e. Category III and
IV) => RCC until proven otherwise.
• IIF - No set rules : Follow up at 6
months
• if the lesion is stable then double
the follow up time.

18. MULTICYSTIC DYSPLASTIC KIDNEY (MCDK)
• Non-heritable paediatric cystic renal
disease
• Affected kidney has no functioning
renal tissue (replaced by multiple
cysts).
• Usually unilateral : predisposition
for the left kidney.
• Unilateral male > female
• Bilateral female > male
• If undiagnosed - complete
involution - renal agenesis during
childhood.
• Diagnosis : ANTENATAL
ULTRASOUND (evident as early as
15w POA)
 Multiple clusters of large cysts of
varying sizes and noncommunicating.
 Atresia of renal pelvis and ureter.
 Echogenic(unidentifiable) renal
parenchyma with small or absent hilar
vessels.
 May look like dilated calyces or
hydronephrosis.

19. • Other modality :
• MRI – demonstrable on T2
• Nuclear imaging –to assess
obstruction.
• Generally void is seen on renal bed
compared to contralateral side.
• No excretion is seen.
• Outcome :
• Bilateral = fatal
• Unilateral = normal life
expectancy if contralateral
kidney is normal.
• Complications : infection of
MCDK, secondary hypertension

20. POLYCYSTIC KIDNEY DISEASE
Autosomal dominant (ADPKD)
• Hereditary, aka adult polycystic kidney disease.
• Found in 1:400 to 1:1000 individuals.
• Most common cause of ESRF.
• Cystic dilatation of renal tubules from any portion
of nephron -> compression.
• Large echogenic kidneys, micro+macrocysts.
• Visible cysts in US by 30s, ESRF by 60s.
• Associated conditions :
• Other organic cysts : liver, spleen, prostate,
seminal vesicles, ovaries, pancreas
• AV malformation, MV prolapse
• Multiple biliary hamartomas
• Cerebral berry aneurysms
• Hypertension
• Colonic diverticulosis
Autosomal recessive (ARPKD)
• Hereditary paediatric cystic renal disease.
• Less common than ADPKD (1:20,000-50,000).
• Bilateral symmetric microcystic disease occurring
in distal convoluted tubules and collecting ducts.
• Unlike ADPKD, the cysts rarely exceed 1-2 cm in
diameter.
• Associated with congenital hepatic fibrosis, portal
hypertension, biliary tract cystic changes, biliary
dysgenesis.
• Inverse relationship with severity of
associated congenital hepatic fibrosis.
• Early (perinatal/neonatal) : renal disease dominates
• Older children (infantile/juvenile) : liver disease
dominates
• In US, kidneys are echogenic, enlarged, maintain
reniform shape, microcysts.

21. ADPKD

23. OBSTRUCTIVE UROPATHY
 Hydronephrosis/hydroureter
• Evidence of post renal failure
• Variable presentations based on etiology
Clinical correlation :
1. Unexplained renal failure – consider UTO!
2. Urine output changes
• Anuria – bilateral complete UTO
• Normal/elevated – partial obstruction
3. Hyperkalemic RTA
4. Hypertension
5. Lab abnormalities : serum/urine

25. TYPES OF URINARY CALCULI
Composition Contrast Aetiological factors Percentage (%)
Calcium oxalate /
Calcium phosphate
Radiopaque Underlying metabolic disorder, eg
idiopathic hypercalciuria or
hyperoxaluria
In 25% no metabolic abnormality
identified
75
Struvite / matrix Radiopaque Renal infection 10-15
Uric acid Radiolucent Hyperuricaemia / hyperuricosuria
Idiopathic (50%)
6
Cysteine Radiolucent Renal tubular defect 1-2
Other stones (e.g. xanthine stones, which may be related to a metabolic abnormality, or indinavir stones,
which are drug related) are uncommon and account for < 5% of all renal stones.

26. WHERE IS THE OBSTRUCTION?
UNILATERAL
HYDRONEPHROSIS
*Proximal etiology*
Renal pelvis
Ureter – intrinsic/extrinsic
BILATERAL HYDRONEPHROSIS
*Systemic or distal etiology*
Bladder
Urethra
Prostate Dilated renal pelvis Dilated pelvis and calyces

28. DIAGNOSIS
• Early diagnosis and decompression
in CRITICAL to prevent renal failure
ULTRASONOGRAPHY
• Modality of choice
PLAIN KUB RADIOGRAPH
 Enlarged renal shadows
 Heavy metal densities : renal stones
 Tumor metastases to bones of
spine/pelvis
PLAIN CT UROGRAPHY
• Modality of choice for urolithiasis
 Size
 Location
 Identify masses/Inflammation causing
extrinsic obstruction
 Identify obstructive atrophy
CT/Plain film + ultrasound will make the diagnosis of ureteral
obstruction in ~90% cases

31. RENAL MASS
 Benign
› Adenoma
› Hamartoma
› Oncocytoma
› Haemangioma
› Multilocular cystic nephroma
 Malignant
› Renal cell carcinoma
› Wilm’s tumour
› Sarcoma
› Lymphoma and leukaemia
› Metastatic
› Transitional cell carcinoma
› Squamous cell carcinoma

32. RENAL CELL CARCINOMA
• Primary malignant adenocarcinomas
• Most common malignant renal tumour
(85%)
• Derived from the renal tubular
epithelium (proximal convoluted
tubule)
• Usually occur in 50-70-year-old
patients (2M:1F)
• Useful clinical information
Macroscopic haematuria: 60%
Flank pain: 40%
Palpable flank mass: 30-40%
Paraneoplastic syndrome
 Hypercalcemia (20%)
 Hypertension (20%)
 Polycythaemia – from erythropoietin
secretion (~5%)
 Feminisation

33. • US
• Small RCC - hyperechoic
• Larger RCC – 86% isoechoic (± central necrosis)
• Cystic tumours : thick or irregular walls with
variably sized intracystic tumour nodules
• Colour Doppler : this can detect any IVC thrombus
together with any extension into the intrahepatic
IVC
• Computed Tomography : for staging
• NECT - a solid mass of heterogeneous attenuation
(>20HU) with low-density central areas ▶
calcification can be present (5–10%)
• CECT - increased attenuation > 20HU is consistent
with malignancy
• Perirenal fat thickening + irregular renal margin =
renal capsule invasion
• Look for renal vein or IVC thrombus too!
(Tumour + thrombus = may migrate)
• MRI
• T1W - low-to-intermediate SI ▶
• T2W - slightly high SI ▶
• T1W post Gad - immediate heterogeneous
enhancement which decreases on delayed
images
*Homogeneous enhancement is more likely in
small, low-grade tumours*
• Venous invasion – more superior to CT in
differentiating benign from malignant
thrombus in either the renal vein or IVC
• T1W - normal flow voids are replaced
by relatively high tumour SI

34. HORSESHOE KIDNEY

35. VENOUS INVASION

36. WITHIN
KIDNEY
CONFINES WITHIN
GEROTA’S FASCIA
EXTENDS BEYOND
GEROTA’S FASCIA

38. RENAL CALCIFICATION
Nephrocalcinosis
• Calcification in renal cortical substance
(1)
• Granuloma, infection, infarction,
xanthogranuloma, neoplasm
• Calcification in renal pyramids
• Medullary sponge kidney (3), RTA (2),
Renal papillary necrosis (4)

39. LOBAR NEPHRONIA
• Acute lobar nephritis
• focal region of interstitial
nephritis.
• intermediate stage
between acute
pyelonephritis and renal
abscess
• wedge of poorly perfused
renal parenchyma,
without a cortical rim sign

40. PYELONEPHRITIS
• Inflammation of renal parenchyma,
pelvis, calyces.
• Imaging is not required.
• Situations in which imaging is
indicated include:
• exclude obstructed kidney
• high-risk patients: diabetics, elderly,
immunocompromised
• those with a mixed clinical picture
• previous renal pathology
• US
• Insensitive, most are normal
• Useful for local complications
detection
• Possible abnormalities :
 debris in the collecting system
 reduced areas of cortical vascularity
by using power Doppler
 gas bubbles (emphysematous
pyelonephritis)
 focal/segmental hypoechoic regions
 mass like lesion

41. • CT
• Sensitive but radiation burden (esp. young
people)
• CT IVU at nephrogenic phase (single phase is
enough)
• Non-contrast CT
• affected parts of the kidney may appear
swollen and of lower attenuation
• renal calculi or gas within the collecting
system may be evident
• Postcontrast CT
• Swollen one or more focal wedge-like regions
• Reduced enhancement compared with the
normal portions of the kidney
• periphery of the cortex is also affected,
distinguishing from a renal infarct (which tends to
spare the periphery, the so-called 'rim sign')
• If for some reason the kidney is imaged again
within 3-6 hours, persistent enhancement of the
affected regions may be evident due to slow flow
of contrast through involved tubules.

42. RENOVASCULAR DISEASE
 5-10% of secondary HPT : renal
parenchymal disease or renovascular
disease
 1-5% caused by renal artery stenosis
 Renovascular HPT is renin-dependant
elevation of BP secondary to renal
ischaemia
 ↓glomerular perfusion detected by
baroreceptors in juxtaglomerular
apparatus  renin release 
angiotensin II  vasoconstriction
 Atheromatous renal artery stenosis 
70-80% of RAS, most common in men
> 50yo
 Involves origin or proximal 3rd of renal
artery.
 Plaques are mixture of cholesterol
and fibrous tissue ± calcification
1. Fibromuscular dysplasia  15-20% of
RAS.
2. Takayasu’s arteritis – rare, affects
aorta and its branches associated with
fusiform AAA
3. RAS in children – uncommon, but 4-
20% of children with HPT has RAS

43. Fibromuscular dysplasia (arrow) and
aneurysm (short arrow) of right renal
artery on AP aortogram (left). MRA
shows the same findings(right)
String of beads on angiography.
Normally involves distal main artery
and major branches, maybe bilateral
or involve external iliac or carotid a.

46. Takayasu arteritis.
(A) Axial CT demonstrates diffuse thickening of the wall of the aorta (arrow).
(B) Curved multiplanar coronal reformats demonstrate the bilateral renal
artery stenosis (arrows)

47. URINARY BLADDER WALL THICKENING
• The bladder wall may be considered thickened if :
• >3 mm when distended
• >5 mm when nondistended
• Not distended => difficult to exclude artifactual thickening from a collapsed
bladder
• Well distended => to assess whether the bladder is diffusely thickened or
focally thickened

48. Diffuse bladder wall thickening
• Neurogenic bladder
• Infectious cystitis
• Cystitis from radiation or chemotherapy
• Chronic bladder outlet obstruction

49. Focal bladder wall thickening
 Urothelial/ transitional cell carcinoma of the
bladder
 Malignancy due to environmental carcinogenic
influences
 Tobacca smoke (60-70%)
 Diet : chlorinated water, coffee, tea, artificial
sweetener
 Occupational : amine fumes, aerosol
 Genetic susceptibility : smoke-related, body
cannot metabolize aromatic amines found in
tobacco
 Prolonged duration of inflammation : infection,
poor emptying, CBD, medications
 Artifact : blood products / clot
 may be adherent to the bladder wall, like tumor,
but clot is more likely to have a concave margin,
unlike tumor
 Other bladder neoplasm
 Squamous cell carcinoma of bladder
 Adenocarcinoma of bladder
 Bladder lymphoma
 Small cell carcinoma of bladder
 Cystitis : more commonly diffuse than focal, but
may mimic neoplasm
 Adjacent inflammatory process (e.g diverticuliltis)
 Cystitis cystica - metaplasia of the urothelium
 may mimic bladder cancer
 Cystitis glandularis – buds differentiate into cystic
deposits
 may mimic bladder cancer
 Amyloidosis - rare
 Malacoplakia - rare

50. TCC

51. URETHRAL INJURY
• The male urethra is much more
commonly injured than the female
urethra
• most commonly result from trauma
• Clinically
• blood of the external urethral meatus
or vaginal introitus
• Hematuria
• Inability to vvoid
• Blood on DRE
• Perineal ecchymosis.
• Partial or complete.
• Causes :
• Blunt trauma : due to shearing or straddle
injuries (usually affects prostatic or
membranous urethra), may associate with
pelvic fractures and often with bladder injury
• Penetrating trauma : e.g. stab wounds,
gunshot wounds, dog bites (more commonly
affect the anterior urethra)
• Iatrogenic eg. catheterisation, Foley catheter
removal without balloon deflation, cystoscopy,
post-surgical (e.g. surgery for BPH)
• Urethral stricture is the most common
long-term complication.

52. • Type I : stretching of posterior urethra due
to disruption of puboprostatic ligaments,
though the urethra is intact
• Type II : posterior urethral injury above
urogenital diaphragm
• Type III : injury to membranous urethra,
extending into proximal bulbous urethra
(i.e. with laceration of urogenital
diaphragm)
• Type IV : bladder base injury involving
bladder neck extending into the proximal
urethra
• internal sphincter is injured, hence potential
for incontinence
• Type IVa : bladder base injury, not involving
bladder neck (cannot be differentiated from
type IV radiologically)
• Type V : anterior urethral injury (isolated)
GOLDMAN CLASSIFICATION OF URETHRAL INJURIES

53. GOLDMAN CLASSIFICATION OF URETHRAL INJURIES

54. 1 2 3
4 4a 5

55. FEMALE
PATIENT

56. A moderate volume of extraperitoneal pelvic haematoma is demonstrated, partially mixed with the extravasated contrast and
presumably urine. There is further pooling of the extravasated contrast on the intravenous-contrast enhanced study,
particularly posterosuperiorly anterior to and within the right SI joint.

57. Stricture following traumatic
bulbomembranous urethral
distraction injury. Combination of
MCUG and ascending urethrogram
defines both proximal and distal
ends of the stricture
Prostatic urethro-rectal fistula post
urethral disruption and a rectal injury.
MCUG demonstrates distal prostatic
urethro-rectal fistula with urethral
stricture just distal to the fistula.

58. • Urethral injury in penile fracture.
Retrograde urethrogram reveals contrast
extravasation in the penile urethra adjacent
to the site of the corpus cavernosal injury
• Rupture of the corpus cavernosum from
trauma to the erect penis (penile fracture)
is an uncommon injury and usually occurs
during strenuous sexual activity.

59. RENAL TRAUMA
 Blunt > penetrating injury.
 Incidence increases in pre-existing congenital or
acquired renal pathology (e.g. horseshoe
kidney, renal cysts).
 Multiorgan involvement often a/w serious renal
injury
 The vast majority (98%) of isolated renal injuries are
classified as minor injuries.
• CT is primary modality for the assessment of
suspected renal injuries.
• Clinically significant injuries will have at least one of :
• Macroscopic haematuria
• Loin tenderness and/ or swelling
• Haemodynamic instability
• Fracture of the lower posterior ribs, lower thoracic or
lumbar vertebrae may also be present
• Imaging generally should be reserved for
haemodynamically stable patient
• Haemodynamically unstable => directly to the
operating theatre.
• Complications (3-10%) of renal injuries :
• Urinoma (most common)
• Delayed bleeding (within 1-2 weeks of injury)
• Urinary fistula
• Perinephric abscess
• Hypertension from renal artery injury
• Hydronephrosis
• Pyelonephritis

60. • CT Renal 4 phase (modality of choice)
• AAST grading
• Most important, CT can help differentiate
trivial injuries from those requiring
intervention.
• US
• Can detect free fluid => hemoperitoneum
• MRI
• When there is a contraindication for
iodinated contrast material or when CT is
not available
• Intravenous Urography
• Assessment of gross function and the
evaluation of the uninjured kidney in
hemodynamically unstable patients.
• No longer the primary modality for the
assessment
• Angiography
• Offers for treatment with angio-
embolisation
• Venography may be performed to assess
suspected injuries to the renal veins or
inferior vena cava.

63. GRADING OF RENAL TRAUMA
American Association for Surgery of Trauma (AAST)
Organ Injury Scale based on :
 Haematoma size (relation to capsule, size, expanding)
 Laceration size (parenchymal depth)
 Urinary extravasation
 Cortex, medulla and collecting system involvement
 Vessel involvement
 Integrity of kidney
 Vascular status
 Whether one or both kidneys involved

66. GRADE I
Small intrarenal hematomas (renal
contusions)
- Ill-defined, round or ovoid
hypoattenuating areas at CT.
- Focal areas of striation on delayed
nephrograms or persistent contrast
material staining.
Subcapsular hematoma
- Round or elliptic hyperattenuating
fluid collection indenting or
flattening the renal margin.
- High-attenuation fluid (40–70 HU;
mean, 51 HU) is most consistent
with acute clotted blood.

67. GRADE II
Minor lacerations
- Defects in the periphery of
the renal parenchyma
without involvement of the
collecting system.
- A limited perinephric
hematoma may be present.

68. GRADE III
• Deep clefts that fill with
hematoma and extend
through the renal capsule
associated with a
perirenal hematoma.
• Perirenal hematomas
with attenuation values in
the 45–90 HU range are
common and may be
large.

69. GRADE IV
• Active hemorrhage tends to
track into surrounding tissues
and has a linear or flame-like
appearance.
• Extravasation of vascular
contrast medium appears with
attenuation values of 80 – 370
HU (+/- 10 –15 HU of the aorta
or adjacent major artery)
surrounded by lower-
attenuation clotted blood.
• Delayed scanning 10 –15
minutes after IV contrast may
show the extent of urinary
extravasation

70. GRADE V
• Shattered kidney : gross renal
parenchymal disruption by multiple
lacerations
• Often associated with multiple areas of
renal infarction.
• Devascularization of the entire kidney
due to laceration or to in situ thrombosis
of the main renal artery
 May occur with or without parenchymal
lacerations.
• If the kidney is devascularized, extensive
retroperitoneal hemorrhage and
hematuria may be absent.

71. REFERENCES
• Management of the Incidental Renal Mass, Stuart G. Silverman, MD, Gary M. Israel, MD, Brian R.
Herts, MD, and Jerome P. Richie, MD
• Radiopaedia.org
• Radiologyassistant.nl
• Natural History of Non-Muscle-Invasive Bladder Cancer, Alon Z Weizer, MD, MS, Christopher Lee, MD,
Khaled S Hafez, MD, and Jeffrey S Montgomery, MD, MHSA
• Diagnositc Radiology Essentials; Grainger & Allison, A. Adam, A.K. Dixon, R.G. Grainger, D.J. Allison
• Imaging of Renal Trauma: A Comprehensive Review; Akira Kawashima, MD, Carl M. Sandler, MD, Frank
M. Corl, MS, O. Clark West, MD, Eric P. Tamm, MD, Elliot K. Fishman, MD, andStanford M.
Goldman, MD
Lifeinthefastlane.com : Renal trauma
• Unequivocal Obstructive Uropathy Radiologic Assessment; Sarah Psutka, 2007 Gillian Lieberman MD
• Ultrasound diagnosis of multicystic dysplastic kidney: is a confirmatory nuclear medicine scan necessary?
Whittam BM, Calaway A

72. IF THIS IS COUNTED AS A SLIDE, THEN ………………….