Urinary tract imaging diagnostic in children

The most common disorders

Urinary tract in children - methods of diagnostic imaging        Ultrasonography (US) Plain abdominal rentgenogram Conventional intravenous urography (IVU) Scintigraphy (renal cortical scintigraphy, diuresis renography) Voiding cystourethrography (conventional and sonocystourethrography) Computed tomography Magnetic resonanse tomography / MR urography (MR hydrography)

Urinary tract in children - methods of diagnostic imaging Voiding cystourethrography (VCU) • remains the gold-standard examination for imaging the bladder and the urethra and for detecting vesicoureteral reflux • detecting VUR in children with a history of urinary tract infection or prenatal diagnosis of abnormal dilatation • • examination should not be performed during acute infection or immediately after treatment patient should be maintained on antibiotics until the examination is performed

Urinary tract in children - methods of diagnostic imaging Voiding cystourethrography (VCU) - technique • • • • • placing of catheter retrograde access (main risk is post-procedural infection sterility extremely important!) suprapubic approach (in neonates with posterior urethral valves, in case of urethral trauma, hypospadias, cloacal malformation) the bladder is filled with a diluted c.m. (120mgI/ml) bladder capacity (ml) = [age (years) + 2] x 30 *(2 or 3 cycles of bladder filling) - cycling VCU has been shown to be more efficient in detecting VUR voiding pictures – centered AP view in girls, oblique in boys to analyze urethra if VUR is detected during micturition – oblique bladder views to visualize the refluxing urether with its retrovesical portion a post voiding film – to assess residual urine

Urinary tract in children - methods of diagnostic imaging Voiding cystourethrography (VCU)

The most common urinary tract disorders in childhood     Urinary tract infections Abnormalities of micturation Abdominalgia Haematuria Asymptomatic children but:  Abnormalities found prenataly in US  Incidentally found abnormalities in US

Urinary tract infections

UTI – one of the most common bacterial diseases in children the prevalence varies with age and sex much more common in infant boys, in school-age group occur mainly in girls SYMPTOMATIC UTI   HIGHER-TRACT INFECTIONS acute pyelonephritis and pyelitis high fever, generalized symptoms (newborns, younger children) LOWER TRACT INFECTIONS acute cystitis voiding symptoms (older children)

Urinary tract infections

ACUTE PYELONEPHRITIS VESICO-URETERIC REFLUX FORMATION OF SCARS REFLUX NEPHROPATHY = CHRONIC PYELONEPHRITIS RENAL HYPERTENSION RENAL FAILURE

Urinary tract infections

• • • • IMAGING GOAL : identification of individuals with complicated UTI, those with abnormalities of the kidneys, VUR or bladder dysfunction Infection - may be the main sign of majority of congenital urinary tract anomalies!

Vesico-ureteric reflux Vesico-ureteric junction obstruction Ectopic ureter Ureterocele • US • Voiding cystourethrography • IVU, MR urography

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Urinary tract infections

Acute pyelonephritis US Increased renal volume Areas of increased or heterogeneous echogenicity (high echogenicity of the parenchyma, especially the renal cortex, hypo- or non-echogenic foci representing microabscesses, larger defect in necrosis, demarcation of abscess formation) Loss of corticomedullary differentiation Thickening of pelvic wall (> 0.8 mm) Renal sinusal hyperechogenicity Increased perirenal fat echogenicity Ureteritis with ureter wall thickening Sedimentation in the bladder or renal pelvis Perirenal fluid collection in perinephritis

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Urinary tract infections

Acute pyelonephritis US (Colour Doppler and power Doppler sonography) Segmental perfusion defects Areas of devascularization Non-perfusion in abscess formations Adjacent hyperperfusion Chronic pyelonephritis   Diffuse or local scarring (the echogenicity increases, a lost of cortical medullary differentiation is observed) Volume measurements (to detect a stagnation of growth in the renal parenchyma)

Urinary tract infections

Acute pyelonephritis (US, transverse prone scan of both kidneys) L kidney - more echogenic with pelvic wall thickening US (sag scan) sinusal hyperechogenicity

Urinary tract infections

Acute pyelonephritis (US) tumefactive hyperechogenicity of the upper pole of the R kidney (US-PD) lack of vascularization of this area

Urinary tract infections

Chronic pyelonephritis (US, sag) - scarred kidney small R kidney with thinning of the renal parenchyma and calyceal dilatation at the upper pole Cystitis US (sag scan) thickening of the bladder wall > 3.5mm

(irregular and/or pseudo-tumoral), urine within the bladder may be echogenic

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Urinary tract infections

Acute pyelonephritis CT the ionizing hazards and the need of contrast injection prevent a routine use in the acute phase should be used if the clinical progression under appropriate therapy is not favorable or if an abscess is suspected may be helpful in cases of a poorly functioning kidney and in case of underlying lithiasis lesions are best demonstrated on the late post-injection phase and appear as hypodense striated triangular-shaped areas within the renal parenchyma

Urinary tract infections

Acute pyelonephritis (CE-CT) triangular-shaped areas of decreased enhancement corresponding to the diseased parenchyma Evolution towards an abscess formation at the right middle and upper pole renal parenchyma appears necrotic and does not enhance

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Urinary tract infections

Acute pyelonephritis MR can detect renal scarring and acute edema (hypointense on T1 CE) DWI - to ascertain abscess formation and to differentiate between acute and more chronic inflammatory lesions MR-urography - visualization of the urinary tract or renal function analysis Voiding cystourethrography because of a significant association between pyelonephritis and VUR, children should be studied to assess reflux up to several weeks after the acute infection gives the possibility to grade VUR, to visualize intrarenal VUR, to evaluate the bladder function and to display urethral anomalies

Urinary tract infections

Acute pyelonephritis (CE-MR, cor) early phase, heterogeneous enhancement of the left upper pole late phase, no enhancement of the upper pole parenchyma is visible

Abnormalities of micturation

    Posterior urethral valve in boys Urethral meatal stricture in girls Ectopic – urethral – orifice of ureter Neurogenic urinary bladder • US • Voiding cystourethrography • Cystometric and uroflowmetric examinations

Haematuria

 Kidney parenchyma diseases (eg. glomerulonephritis)  Urolithiasis • US • Plain abdominal rentgenogram • IVU, MR urography

Abdominalgia

 Urinary tract infections (pyelonephritis, cystitis)   Hydronephrosis of any cause Urolithiasis • US • Plain abdominal rentgenogram • Voiding cystouethrography • IVU, MR urography

         Some of the congenital anomalies of urinary tract in children Vesico-urinary reflux – incompetent ureteral sphincter Double kidney and pelvicocaliceal system ureter duplex (with ectopic ostium) ureter fissus Ureteral strictures (pelvico-ureteral and vesico ureteral) Posterior urethral valve in boys Urethral stricture in girls Ureterocele (simple or ectopic) Ectopic kidneys, Horseshoe kidney, one kidney Polycystic kidneys (ARPKD and ADPKD) Multicystic dysplastic kidney

Vesico-ureteric reflux

intramural

0

segment submucosal segment

+

 VUR results from the lack of a normal valve-like mechanism of the vesicoureteric orifice the competence of the vesicoureteric junction is influenced by the length of the intravesical segment of the ureter: a shorter distance is likely to result in VUR

Vesico-ureteric reflux

Ureterovesical junction Ureteral orifices divericula

Vesico-ureteric reflux

• primary VUR - mainly in neonates and in infants, ♂ , congenital anomalies of the kidneys and urinary tract • secondary VUR - results from/is associated with various uronephropathies, school-age ♀ with bladder dysfunction ♂ Frequent familial occurrence (40-65% siblings will be affected) Prevalence of VUR in healthy children is ~ 1-2%

Vesico-urinary reflux

VUR grading Grade I VUR limited to the ureter Grade II VUR up the renal cavities without dilatation Grade III VUR into the renal cavities inducing dilatation and eversion of the calyces Grade IV moderate to marked dilatation of the ureter and pyelocalyceal system Grade V marked tortuosity and dilatation of the ureter and pyelocalyceal system

Vesico-urinary reflux

Dilatated ureter and pelvocaliceal system in the left kidney VUR IV

Vesico-urinary reflux

Cystography – vesico-ureteric reflux IV/V grade

Vesico-urinary reflux

Combined static-dynamic MRU

Vesico-urinary reflux

Combined static-dynamic MRU high-resolution anatomic images of the entire urinary tract + functional information about the concentration and excretion of the individual kidneys dynamic scanning after iv Gd-DTPA bolus injection combination of T2-w and dynamic 3D T1-w sequences

Hydronephrosis

     Ureteral strictures!!!

- pelvico-ureteric junction - vesico-ureteric junction Double kidney with ectopic ureter and ureterocele Posterior urethral valve Nephro/ureterolithiasis Other urinary tract anomalies (retrocaval ureter, ectopic kidneys, VUR)  Causes outside the urinary system Prune Belly syndrome

Hydronephrosis

Differential diagnosis of hydronephrosis   RPD with obstruction RPD with no obstruction Megaureter (with or without reflux) Multicystic dysplastic kidney VUR with upper-tract dilatation Bladder outlet obstruction (commonly posterior urethral valve) Complicated duplex kidney Upper moiety dilatation, due to either a ureterocele or ectopic drainage of the ureter Lower moiety dilatation, due to either VUR or less commonly RPD RPD - renal pelvic dilatation

hydronephrosis

Left vesico-ureteral stricture Double left kidney with dilatated lower pelvicocaliceal system – possible ectopic left lower ureter

PUJ stricture

hydronephrosis

hydronephrosis PUJ obstuction VUJ obstruction

hydronephrosis

Horseshoe kidney Pelvic kidney IVU– VUR V

Prune Belly syndrome

IVU VCUG

ureterocele

  Simple – in single kidney, ostium in vesical triangle, balloon-like deformation of intramural fragment of ureter, usually small, without hydronephrosis, contrast-filled mass in bladder (urography) Ectopic – in double kidney, ectopic, anomalous ostium of (usually) upper ureter, dilatation (may be huge) of whole ureter and pelvicocaliceal system, often kidney dysfunction, defect in contrast-filled bladder (urography)

ureterocele

Left renal obstruction due to ureterocele Cobra-head ureterocele

ureterocele

ureterocele

Bilateral hydronephrosis, left double kidney, invisible upper P-C system, ectopic left ureterocele

Urethra – normal appearance

Urethral obstruction

boys

Male urethra posterior part dilatation posterior urethral valve Normal urethra – impression of urogenital diaphragm

Urethral obstruction

girls

Female urethra Meatal stenosis

Cystic diseases of kidneys

 ARPKD – autosomal recessive polycystic kidneys disease  ADPKD – autosomal dominant polycystic kidneys disease  Multicystic dysplastic kidney – nonheritable kidney disorder

Multicystic dysplastic kidney

      ONE KIDNEY! affected Obstruction of urinary drainage of affected kidney (ureter atresia, distal ureter obstruction, ectopic ureteral insertion) Large cysts easily seen in USG, no normal renal parenchyma No function in the kidney Possible VUR to functioning kidney (25%) – voiding cystography is recommended Dysplastic kidney has a tendency to involution with time

Multicystic dysplastic kidney

No renal function on the right (IVU) Multiple cystic formations in US and CT

ARPKD – autosomal recessive polycystic kidneys disease  Both kidneys and liver (ectasia of collecting tubules in kidneys and biliary ducts in liver, fibrosis)  Very large kidneys (up to 10 cm in a neonate)  Death in infancy or first decade of life due to renal failure, systemic and portal hypertension

US ARPKD – autosomal recessive polycystic kidneys disease CT IVU

ADPKD – autosomal dominant polycystic kidneys disease       Both kidneys, may be asymmetrically involved Also liver and pancreas Large and more numerous cysts with increasing age Renal failure or hypertension in the fourth-fifth decade of life Clinical symptoms – rare in childhood (kidney enlargement, haematuria, flank pain if bleeding into the cyst US screening of parents and siblings of affected child should be routine

ADPKD – autosomal dominant polycystic kidneys disease

Urolithiais and nephrocalcinosis

 Urolithiasis – calculi in renal pelvis and calices, ureters and urinary bladder, due to kidneys obstruction, anomalies or metabolic disorders  Nephrocalcinosis – calcifications in renal parenchyma, in dilated tubules in sponge kidney

Urolithiais and nephrocalcinosis

Nephrocalcinosis – calcifications in renal parenchyma Urolithiasis – stones in distended calices

Urolithiais and nephrocalcinosis

IVU Nephrocalcinosis CT Plain film Renal calculi in pelvocaliceal sysem and in VUJ