This document discusses different types of stones that can form in the urinary tract, including calcium oxalate, phosphate, uric acid, and struvite stones. It also discusses conditions that can mimic stones on imaging, such as nephrocalcinosis, phleboliths, pancreatic and adrenal calcification, dermoid cysts, gallstones, and vascular and renal calcification. Stones can cause obstruction of the urinary tract and lead to hydronephrosis. Specific stone locations like ureteric, bladder, and jack stones are also covered.

1. Urolithiasis Imaging
PPT BY BASHEER HASAN OUDAH

2. Types of Stones

3. Calcium Oxalate Stones
 80% of kidney stones contain
calcium
 General appearance:
1. White, hard, radiopaque
2. Calcium PO4: staghorn in renal
pelvis (large)
3. Calcium oxalate: present in
ureter (small)
4. Called Mulberry stone (brown)
with sharp projections.

4. Phosphate Stones
 10-15%
 Either be Calcium phosphate
(magnesium or ammonium)
 Occurs in infection
 Smooth and white color
 In alkaline urine, it enlarges
rapidly, filling renal calyces
and taking their shape
(STAGHORN CALCULUS).
 Radiopaque

5. Uric Acid Stones
 8% of renal stones contain uric
acid
 associated with hyperuricemia
(with or without gout)
 General appearance:
1. Small, friable, yellowish
2. May form staghorn
3. Radiolucent (plain x-rays
cannot detect)

6. Struvite Stones
 Compound of magnesium,
ammonium phosphate mixed
with carbonate.
 associated with chronic UTI
 Occurs in presence of
ammonia and urea splitting
organisms in urine (e.g.
Proteus, Klebsiella)
 Radiopaque

7. Staghorn Calculus
 Stone occupying the renal
pelvis and calyces
 Triple phosphate stone
 White in color, soft, smooth
occurs in pre-existing
infection.
 Unilateral/Bilateral

8.  Caliceal calculi that are non-obstructing are usually
asymptomatic.
Patients with small caliceal calculi may still have gross or
microscopic hematuria and may have colic symptoms despite
the lack of imaging findings suggestive of obstruction.

9. Calculi causing Hydronephrosis
 Hydronephrosis is dilatation of the renal pelvis and calyces.
 It can be caused by obstruction of the ureters or bladder outlet. Hydronephrosis can also
result from reflux (retrograde leakage of urine from the bladder up the ureters to the
renal pelvis.

10. Ureteric Calculus
1. Always of Renal Origin
2. Commonly of elongated shape
3. Can get impacted at 3 constrictions of
ureter
4. Can cause:
Obstruction
Hydronephrosis
Infection
Ureteral Stricture
5. C/F:
Colicky Pain (from loin to tip genitalia)
along genitofemoral nerve.
Hematuria, dysuria, frequency,
strangury
Tenderness in iliac fossa

13. Bladder Calculus
1. Primary vesical calculus:
• occurs in sterile urine
• Comes down from kidney through ureter
and gets enlarged in bladder (usually
oxalate stone).
• Can irritate bladder mucosa causing
hematuria
2. Secondary vesical calculus:
• Occurs in presence of infection
(commonest bladder stone)
• Usually phosphate stone, occurs in
bladder only

14. Etiology
 Same as that of Renal
Calculus
 Others:
1. Diverticula bladder: which
lead to stagnation of urine 
superadded infection  stone
formation
2. BPH
3. Urethral Stricture
4. Neurogenic Bladder
5. Schistosomiasis

15.  Bladder stones generally form in
the bladder itself.
 Causes:
1. bladder outflow obstruction
(enlarged prostate)
2. neurogenic bladder (loss of
bladder function due to spinal
cord injury/disease).
3. Those with bladder wall
abnormalities (ureterocele,
diverticulum) or
4. those with recurrent urinary
infections are also at higher risk
of forming bladder stones.
 When seen on an
abdominal/pelvic X-ray they are
often multiple and rounded.

16. Bladder Stone
 Note that this stone has a
faint longitudinal lucency
which is the nidus around
which the stone developed.

17. Jack Stone
 Jackstone calculi resembles toy
jacks.
 composed of calcium oxalate
dehydrate
 dense central core and radiating
spicules.
 light brown with dark patches
and are usually described to
occur in the urinary bladder and
rarely in the upper urinary tract.

18. Bladder Stone

19. Conditions Mimicking
Calculi

20. Nephrocalcinosis
 Refers to renal parenchymal
calcification. The calcification may be
dystrophic or metastatic.
1. With dystrophic calcification, there is
deposition of calcium in necrotic
tissue.
This type of parenchymal calcification
occurs in tumors, abscesses, and
hematomas.
2. Metastatic nephrocalcinosis occurs
most often with hypercalcemic states
caused by hyperparathyroidism, renal
tubular acidosis, and renal failure.
Metastatic nephrocalcinosis can be
 further categorized by the location of
calcium deposition as cortical or
medullary.

21. Causes of Nephrocalcinosis
 Causes of cortical nephrocalcinosis include
1. acute cortical necrosis
2. chronic glomerulonephritis
3. chronic hypercalcemic states
ethylene glycol poisoning, sickle cell disease, and
rejected renal transplants
 Causes of medullary nephrocalcinosis include
1. hyperparathyroidism (40%)
2. renal tubular acidosis (20%)
3. medullary sponge kidney
bone metastases, chronic pyelonephritis, cushing’s
syndrome,
hyperthyroidism, malignancy, renal papillary
necrosis,sarcoidosis, sickle cell disease, vitamin D
excess, and Wilson’s disease.

22. Phleboliths
 Calcification within venous
structures.
 Common in the pelvis where they
may mimic ureteric calculi, and
are also encountered frequently in
venous malformations.
 Round in shape (but not always)
of a similar size that would
correspond to the diameter of
pelvic veins
1. look like a ring of bone
2. tend to occur laterally around the
urinary bladder
3. appear as focal calcifications,
often with radiolucent centers

23. Pancreatic calcification
 retroperitoneal organs such as
the pancreas which only
become visible when calcified.
Pancreatic calcification is a
feature of chronic pancreatitis.

24. Adrenal Calcification
 Adrenal (suprarenal)
calcification is an uncommon
finding and is usually
incidental. Most often it is
considered a result of
previous haemorrhage or
tuberculosis.

25. Dermoid cyst

26. Gallstones (10% radiopaque)
 Radiopaque lucency in the RUQ
and presents with typical
laminated appearance
 Note anterior location on lateral
projection

27.  Gallstones have a variable
position depending on the
position of the gallbladder and
may be mistaken for renal
stones
 Unlike renal stones they are
often rounded and cluster
together

28. Appendicolith
 Small calcified stone
within the appendix,
and is seen in the
right iliac fossa.

29. Vascular Calcification
 Calcification of arteries seen
on x-rays is a sign of more
generalised atherosclerosis.
 Occasionally vascular
calcification seen on an
abdominal X-ray reveals an
unexpected aneurysm

30.  Typical appearance of
calcified abdominal aorta
 Note the outward bulging of
the anterior wall

31. Renal Tuberculosis
 Genitourinary tract
tuberculosis. Lobar
calcification in a large
destroyed right kidney in a
patient with renal
tuberculosis. Note the
involvement of the right ureter

32. Miscellaneous X-Ray Abdomen
Calcification

33. 1. Calcified vas deferens

34. The calcified arrowed structures are likely
to be calcified injection sites.

35.  The calcified lesions at the bottom
of the image are scrotal calculi
which are also known as a fibrinoid
loose bodies or scrotal pearl.
 Scrotoliths or scrotal pearls
are benign incidental extra
testicular macro-calcifcations within
the scrotum. They frequently occupy
the potential space of the tunica
vaginalis or sinus of the
epidydimis. They are usually of no
clinical significance.
 Causes
micro trauma / repetitive trauma to
scrotal region - e.g. mountain bikers
prior torsion appendix of testis
Scrotoliths/Scrotal Pearls

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