Diagnostic Ultrasound - Abdomen and Pelvis

Bladder Calculi
TERMINOLOGY
Synonyms
• Bladder stones, vesical calculi, cystolithiasis
Definitions
• Concretions of mineral salts/crystal within bladder lumen
IMAGING
General Features
• Best diagnostic clue
○ Mobile avascular echogenic focus/foci in bladder with
acoustic shadowing on US
○ Smooth, round or ovoid, lamellated calcification in
bladder region on plain radiograph
• Location
○ Bladder lumen: Usually midline with patient supine
– Eccentric location in patients with bladder
augmentation or diverticulum
• Size
○ Variable (tiny migrated renal stones to large inherent
bladder stones)
• Morphology
○ Round, oval, spiculated, lamellated, faceted
Ultrasonographic Findings
• Grayscale ultrasound
○ Mobile, avascular, crescentic echogenic focus with sharp
acoustic shadowing
○ Occasionally stone adheres to bladder wall due to
inflammation
○ Associated bladder wall thickening and internal echoes
or debris in bladder lumen may be seen
○ Edema of ureterovesical junction may be seen with
recent passage of ureteral stone into bladder
Radiographic Findings
• Radiography
○ Solitary or multiple calcifications overlying bladder
region
○ Mostly radiopaque but opacity can be variable;
radiolucent stone = cystine or uric acid stone
CT Findings
• Calcific density in bladder, of varying size and shape, often
lamellated on NECT or CECT
○ Filling defect on CT urogram
MR Findings
• All pulse sequences: Signal void(s) in bladder, typical filling
defect on T2WI
DIFFERENTIAL DIAGNOSIS
Bladder Neoplasm
• Focal immobile mass in bladder, with internal vascular flow
Blood Clot
• Avascular hypo-/hyperechoic foci without posterior acoustic
shadowing, ± internal echoes
• History of hematuria can be helpful clue
Fungal Ball
• Rare entities occurring in diabetics or
immunocompromised patients
• Medium echogenicity, nonshadowing, rounded mobile
lesions within bladder
Prostatomegaly
• Median lobe hypertrophy may indent bladder base,
mimicking stone
PATHOLOGY
General Features
• Etiology
○ Stasis: Bladder outlet obstruction, neurogenic bladder,
bladder diverticula
– Concentrated, stagnant urine crystallizes in bladder
○ Migrated renal calculi
○ Infection, especially proteus mirabilis
○ Foreign bodies: Act as nidus for crystal growth
○ Bladder augmentation: Local metabolic derangement
• Most are mixture of calcium oxalate and calcium phosphate
• Infection stones: Magnesium ammonium phosphate
("struvite")
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Most asymptomatic
○ May present with hematuria, suprapubic pain, and
repeated UTI
Demographics
• Gender
○ M > F
Natural History & Prognosis
• Complication: Malignant bladder tumors in patients with
stones from indwelling Foley catheters
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Carcinoma resulting from chronic bladder irritation may
coexist with bladder stone
SELECTED REFERENCES
1. Celik S et al: Association between ureteral jet dynamics and nonobstructive
kidney stones: a prospective-controlled study. Urology. 84(5):1016-20, 2014
2. Shih CJ et al: Urinary calculi and risk of cancer: a nationwide populationbased
study. Medicine (Baltimore). 93(29):e342, 2014
3. Hammad FT et al: Bladder calculi: did the clinical picture change? Urology.
67(6):1154-8, 2006
4. Schwartz BF et al: The vesical calculus. Urol Clin North Am. 27(2):333-46,
2000
Diagnoses: Urinary Tract
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