JC Block C - Diagnostic Radiology - Urinary system

Question 1

Causes of renal pseudomasses

Answer 1

The renal parenchyma results from the fusion of several segments during intra-uterine life
 Each segment is functionally independent

 Abnormal fusion is possible

 lobulation/ junctional segment - pseudomass – normal variation***

Question 2

All modalities of urinary imaging

Answer 2

A. Plain radiograph (KUB):
B. Intravenous urogram (IVU):
C. Ultrasound:
D. Computed tomography:
E. Magnetic resonance imaging (MRI):
F. Arteriography:

Question 3

Function of Plain radiograph (KUB)

Answer 3

Can see:

Kidneys
 Calcification (calculi, Staghorn calculus)
 Size (2.5 vertebrae)
 Outline (masses)
 Position

Ureters
 Tips trans processes
 Cross pelvic brim at SIJ
 Run in paraspinal region
 calcification

Bladder
 Calcification
 Outline

Question 4

Intravenous urogram (IVU)

Structures seen

Answer 4

series of KUB radiographs with IV administration of iodinated contrast media:
Contrast excreted by kidneys (glomerular filtration) and can be seen on film

Opacifies:
 Pelvicalyceal systems
 Ureters
 Urinary bladder

Question 5

IVU sequence

Answer 5

Question 6

Lesions

Answer 6

Renal masses:
L = Polycystic kidney (enlarged kidney; round
areas of radiolucencies)
 R = Large renal cyst (well circumscribed)

Question 7

Lesion

Answer 7

Horseshoe kidney (joined at midline, increased risk
of RCC)

Question 8

Lesion

Answer 8

Transitional cell carcinoma of bladder

Stipple sign - trapping of contrast material within the interstices of a papillary growth produces a stippled appearance when viewed end on

Question 9

Function of Ultrasound in urinary system

Answer 9

 Renal size and morphology

 Renal parenchyma + abnormal calcifications: normal Dark cortex and echogenic/ fatty medulla

 Obstruction – hydronephrosis: dilated renal calyces

 Renal vessels – transplanted kidneys, renal artery stenosis

 Masses – cyst vs. solid masses E.g. bladder cancer (TCC)

Question 10

Lesion

Answer 10

Obstruction – hydronephrosis:
 Renal calyces are normally not seen
 In obstruction, there is backflow and static urine  calyces dilate to become visible
 The obstruction here is chronic because there is cortical thinning

Question 11

Lesion

Answer 11

bladder cancer (TCC):
 Intraluminal masses
 Color Doppler detects feeding blood vessels

Question 12

Lesion

Answer 12

Well-defined echogenic mass in the dependent portion of bladder

Doppler detects no vascularity within this mass

Likely a blood clot - resolves with bladder irrigation

Think causes of haematuria

Question 13

Computed tomography urinary system

Indications

Answer 13

 Further characterisation of abnormalities seen on IVU, KUB, US
 Renal colic
 Cancer staging
 Renal trauma
 CT angiogram for renal artery stenosis

Question 14

Study this

Answer 14

Anatomy:
Hypodense perirenal fat surrounds the kidneys

Fascia separates spaces (pathology originally spreads along the same space):
 Anterior Gerota’s fascia
 Posterior Gerota’s fascia
 Lateroconal fascia

Question 15

Study this

Question 16

Lesion

Answer 16

obstructing calculus causing hydroureteronephrosis:

 Contrast is excreted normally from the left kidney
 But the right kidney has hydrnephrosis, hydroureter due to calculus = delay in
excretion of contrast

Question 17

Lesion

Answer 17

bladder cancer:
 Mass projecting from bladder
 Filling defect when excrete contrast into bladder
 Early enhancement

Question 18

MRI renal system

Indications

Answer 18

a) Further characterization of abnormalities seen on CT urogram
b) Cancer staging
c) +/- renal MRA

Question 19

T staging for renal tumors

Answer 19

T staging:
 T1/T2: confined to kidney

 T3: extension into major veins/ perinephric tissues, but not into ipsilateral adrenal gland or beyond Gerota’s fasica

 T4: involves ipsilateral adrenal gland/ invades beyond Gerota’s fascia

 MRI is needed in T3/T4 to differentiate structures, not in T1/T2

Question 20

Use of MRI in bladder cancer

Answer 20

Need MRI to distinguish:
 Non-muscle invasive (T2a) from invasive (T2b) tumor (disruption of hypointense rim)

 Microscopic (T3a) from (T3b) tumour extension

 T4 (e.g. invasion into uterus, vagina)

Question 21

Urinary Arteriography

Indications

Answer 21

a) Diagnosis and treatment ofrenal artery stenosis
b) Embolization of bleeding tumors or points
c) Diagnosis and treatment of AVM

Question 22

Lesion

Answer 22

renal artery stenosis (catheter inserted into renal artery  use balloon to open up the narrowing)

Question 23

Fluoroscopy:

Types

Usage

Answer 23

Antegrade pyelogram:
Procedure:
 Puncture kidney percutaneously (US-guided)
 Inject contrast into the pelvicalyceal system

Retrograde pyelogram:
Procedure:
 ureteric catheter is inserted via the cystoscope into the ureter
 Contrast is injected via the ureteric catheter

Question 24

Imaging study of choice for renal stones

Treatment options for renal stones

Answer 24

Ix for acute flank pain/ suspicion of stone disease:
 Noncontrast CT KUB

(ESWL = extracorporeal shock wave lithotripsy; URS = ureterorenoscopy; PCNL = percutaneous nephrolithotomy)

Question 25

Indications for imaging acute pyelonephritis

Answer 25

Role of diagnostic imaging:
 Not indicated in mild forms
 To characterise severity and complications
 Patients at risk, e.g. diabetic, elderly, immunocompromised
 To assist diagnosis when the patient fails to respond to appropriate therapy within first 72 hours

US – non-specific findings:
 Hyperechoic/ hypoechoic/ both
 Focal/ global renal enlargement
 Vascular defect

CT:
 Striated nephrogram
 Emphysematous pyelonephritis

Question 26

Treatment of choice for renal stones based on size

Answer 26

Question 27

steps in the differentiation of a renal lesion?

Answer 27

1. Is it a cyst?  benign
2. Does it contain macroscopic fat?  benign angiomyolipoma (AML)
3. Exclude tumor-mimics like infection and infarction, which usually present in different clinical settings.
4. Exclude metastatic disease and lymphoma; kidney involvement usually only seen in widespread disease

Question 28

Case 1:

 F/57: chronic right loin pain

Answer 28

Dx: staghorn renal stone

Question 29

Case 2:
 Young lady: increasing abdominal mass
 KUB: large soft tissue mass in left abdomen displacing bowel

 Plain CT: large mass arising from left kidney; smaller masses in right kidney with fat
densities

Most likely Dx

Answer 29

angiomyolipomata

Question 30

Case 3:
 Young man: deranged renal function

Dx

Answer 30

CT scans:
 Multiple cysts replacing both kidneys
 Some calcification in the walls of the cyst
 Cysts also in the liver
 Pancreas is normal

Dx: Polycystic kidneys

Question 31

Case 4:
 F/42
 History of renal stones
 C/o left loin pain and fever

Imaging and Dx

Answer 31

 KUB: 3 calculi in left kidney

US/ IVU to exclude obstruction in calyx or ureter: focally dilated upper
pole calyx secondary to a calculus

Question 32

Case 5:
 M/52: left loin pain

Dx

Answer 32

CT:
 Right simple cyst
 Left suspicious lesion  renal cell cancer

Question 33

Case 6:
 F/72: painless hematuria

Features, Dx

Answer 33