ASPECTE RADIOIMAGISTICE N LITIAZA RENO-URETERORENO-URETERO-VEZICAL

Litiaza renal reprezint una dintre cele mai frecvente cauze de obstruc ie acut ureteral i are o inciden de aproximativ 12%.

Complica ii: infec ii severe; insuficien renal ; rar letal .

Mecanisme: prezen a n exces a factorilor care favorizeaz precipitarea; absen a substan elor ce inhib cristalizarea; excre ia excesiv a unor s ruri; obstruc ia.

Factori anatomici: sindromul jonc ional; rinichiul n potcoav sau ectopic; boala polichistic renal de tip autozomal dominant; diverticulii caliceali.

St ri patologice ce favorizeaz calculoza: rinichiul n burete; obstruc ia uretral ; diverticuli vezicali; infec ii de tract urinar.

Calculii pot fi:radioopaci oxalat i fosfat de calciu:reprezint 70%; au contururi nete i m rimi variate (calculi coraliformi); 85% sunt idiopatici; 15% au drept cauze HPTH, hipercalciuria i hiperoxaluria.

- struvit (amoniaco-magnezieni): (amoniaco- asocia i infec iilor urinare (Proteus); - au radiodensitate variabil - cistinici: - tulbur ri ale metabolismului cistinei (cistinurie); - calculi matriceali (matrice mucoproteic nvelit de s ruri fosfocalcice); radiotransparen i urici; - xantinici

Aspecte imagistice:Radiografia conven ional : examen de prim inten ie la pacien ii cu suspiciune de litiaz urinar ; f r substan de contrast; eviden iaz calculii radioopaci; se poate efectua n inciden e oblice, n ortostatism pentru deta area imaginii; necesit preg tirea intestinului; parametrii kilovoltaj sc zut: 60-80 KV +/- compresie 60+/ abdominal ; diagnostic diferen ial calcific ri extrarenale (arteriale, venoase, ganglionare, tumorale).

Urografia intravenoas : confirm localizarea calculului n tractul urinar sau n afara lui; pune n eviden eventuale anomalii morfologice (dilata ii caliceale, diverticuli caliceali, duplica ii, sindrom de jonc iune, ureter retrocav); aspectele radiologice sunt:pielogram ntrziat ; nefrogram prelungit i intens ; m rirea ariei renale; dilata ia c ilor excretorii; bombarea cupelor caliceale; extravazare urinar pericaliceal sau perirenal .

sensibilitate 50-60% (90% din calculi sunt radioopaci, 5010% radiotransparen i); specificitate 70%; diagnostic diferen ial cu calcific rile extrarenale, iar n cazul calculilor radiotransparen i cu tumorile cu celule tranzi ionale sau cheaguri de snge.

Tomografia computerizat : sensibilitate 94-97%; 94specificitate 96-100% - cea mai sensibil metod de 96detec ie; detecteaz calculii neobstructivi intrarenali i pe cei invizibili la UIV (calculii calcici 700 UH; cistinici, urici 100100-500 UH); rapid (CT spiral); nu necesit substan de contrast; face diagnosticul diferen ial cu cheagurile de snge intraluminale; sec iuni de 5mm cu pitch 1,5:1 sau 2:1 ; necesit optimizarea dozei; aspecte CT:nefromegalie; calculi intrarenali, ureterali, vezicali; hidronefroz ; colec ii perinefretice; dilata ii ureterale.

Ecografia: eviden iaz calculi intrarenali i la nivelul jonc iunii ureterovezicale; util la pacien ii cu contraindica ie pentru substan a de contrast; pentru caracterizarea defectelor de umplere vizibile la UIV; nu eviden iaz calculi mai mici de 2mm sau la nivelul ureterului mijlociu; estimarea dimensional a calculilor este inexact ; sensibilitate 24%; specificitate 90%; aspecte US: forma iune intens hiperecogen cu prezen a conului de umbr posterior (excep ie calculii matriceali cu ecogenitate similar sinusului renal i f r con de umbr ).

Scintigrafia: eviden iaz reducerea capt rii la nivelul parenchimului renal cu obstruc ie i eventual persisten a insuficien ei func ionale renale dup ndep rtarea obstacolului. Alte metode: ureteropielografia anterograd i retrograd ; rezonan a magnetic nuclear .

LITIAZA VEZICALcalcul migrat de la nivel renal; calcul format in situ ; calcul intradiverticular; calcul n ureterocel; Diagnostic diferen ial: calcific ri tumorale; cheaguri de snge; corpi str ini intravezicali.

Magnified scout intravenous urogram shows a large, relatively lucent calculus in the lower pole of the right kidney.

Scout intravenous urogram shows a smooth, dense, round calculus in the left kidney

Intravenous urogram. After the intravenous injection, contrast material in the collecting system obscures the calculus

Scout intravenous urogram shows a smooth stone in the right kidney

Intravenous urogram obtained 5 minutes after the intravenous injection. Contrast material in the collecting system obscures the stone

This intravenous urogram was obtained 10 minutes after the intravenous injection of contrast medium. Additional contrast material is present in the collecting system, and the stone is seen as a relatively lucent filling defect

Renal sonogram demonstrates an echogenic shadowing calculus in the renal collecting system with hydronephrosis

Contrast-enhanced CT section reveals a dense calculus in the right kidney, but the hydronephrosis has resolved

Abdominal radiograph shows calcification filling the left collecting system. This finding is consistent with a staghorn calculus. For its size, the stone is relatively lucent

Contrast-enhanced CT scan demonstrates an opaque staghorn calculus filling the left renal collecting system

Scout intravenous urogram shows innumerable small calcifications in the region of the renal pyramids in a patient with nephrocalcinosis.

Scout intravenous urogram demonstrates innumerable calcifications over the medullary region of the left kidney in a patient with nephrocalcinosis

Renal longitudinal sonogram in a patient with nephrocalcinosis shows diffuse echogenic shadowing calcifications in the renal pyramids

Intravenous urogram. Prospectively, no stone was seen on the scout radiograph. In retrospect, a stone in the distal left ureter is projected over the lateral edge of the mid sacrum.

This intravenous urogram was obtained 5 minutes after the intravenous injection of contrast agent. A prolonged hyperintense left nephrogram demonstrates delayed contrast material excretion into the left collecting system due to ureteral obstruction.

This intravenous urogram was obtained 10 minutes after the intravenous injection of contrast material. Mild left hydronephrosis and hydroureter extend to the level of the stone in the true pelvis.

Scout intravenous urogram demonstrates a small, focal, almost triangular, radiopaque calculus on the left side of the pelvis. Another pelvic calcification with central lucency is a typical phlebolith.

Scout intravenous urogram was obtained 5 minutes after the intravenous injection of contrast agent. A prolonged hyperintense nephrogram and moderate hydronephrosis are present in the left kidney. The right kidney and collecting system are normal.

Intravenous urogram was obtained 10 minutes after the intravenous injection of contrast agent. A column of contrast material in the left ureter extends down to the calculus noted on the scout radiograph. The small phlebolith can barely be seen projecting slightly off the ureter.

Intravenous urogram (30-minute delay image) of the right kidney shows a moderately hydronephrotic collecting system to the level of a proximal ureteral stone (arrow)

Axial nonenhanced CT section at the level of the kidney demonstrates an attenuating proximal ureteral calculus (arrow). No significant hydronephrosis is identified. CT can be performed much more rapidly than urography and without the use of intravenous contrast material.

Scout intravenous urogram demonstrates several calcifications in the left hemipelvis

Intravenous urogram was obtained 10 minutes after the intravenous injection of contrast agent. A prolonged hyperintense nephrogram and mild hydronephrosis are present.

Intravenous urogram, delayed radiograph, reveals a large amount of contrast material extravasation (likely a fornix rupture with pyelosinus backflow) in the region of the left renal pelvis. Contrast agent fills the distal ureter.

Intravenous urogram, magnified view, shows extravasated contrast agent from a fornix rupture and pyelosinus backflow

Axial nonenhanced CT image at the level of the kidneys shows bilateral renal calculi, right hydronephrosis, and moderate perinephric fluid

Axial nonenhanced CT image of the urinary bladder demonstrates an attenuating calculus at the right ureteropelvic junction

Axial contrast-enhanced CT scan. The excretory phase image through the kidneys shows extravasation of contrast material in and near the renal pelvis and surrounding the proximal ureter, which is opacified. The finding is consistent with fornix rupture

Scout intravenous urogram demonstrates radiopaque left renal calculi in the mid kidney and lower pole

Scout intravenous urogram obtained after lithotripsy shows absence of the previously seen calcification over the mid kidney and linear group of calcifications in the path of the distal left ureter (steinstrasse, from the German, meaning "stone street").

Intravenous urogram, magnified view of the scout image in Image 30, was obtained after lithotripsy and shows a steinstrasse appearance

Intravenous urogram, 10-minute delay image, demonstrates delayed excretion and a slightly hyperopaque left nephrogram due to obstruction by distal ureteral stone fragments. Stents are often placed to prevent obstruction after lithotripsy.

Intravenous urogram, scout radiograph. Large radiopaque calculus overlies the left hemipelvis near the expected location of the ureterovesical junction. Two adjacent phleboliths are noted lateral and caudal to the stone.

Intravenous urogram. Magnified view of the scout radiograph in Image 33 reveals faintly lamellated pelvic calcification at the expected location of the left ureterovesical junction

Intravenous urogram (10-min delay). Contrast-enhanced study demonstrates the left ureterocele as a slightly lucent halo around the previously noted pelvic calcification

Intravenous urogram (10-min delay) Magnified view of the left ureterocele (see Image 35) with a large stone in it

Axial contrast-enhanced CT image through the ureterovesical junction confirms the stone within a left ureterocele. A Foley catheter balloon is visible in the bladder.

Intravenous urogram (tomogram) shows enlarged relatively lucent right kidney with no excretion of contrast material

Intravenous urogram (5-min renal view) shows enlarged relatively lucent right kidney with no excretion of contrast

Longitudinal sonogram of the right kidney demonstrates marked dilatation of the calyces. No calculi are apparent

Sonogram shows marked dilatation of the calyces and communication with the renal pelvis, which confirms severe hydronephrosis

Nonenhanced CT image of the kidneys demonstrates left hydronephrosis and strands of perinephric fluid but no dense calculus

Nonenhanced CT image of the pelvis shows dilatation of the distal left ureter and mild periureteral fluid near the left ureterovesical junction

Nonenhanced CT image of the pelvis shows a small attenuating stone at the left ureterovesical junction

Nonenhanced CT image shows slightly hyperattenuating renal pyramids, most notably on the left. This is a secondary sign and indicates a lack of obstruction of the collecting system

Nonenhanced CT image shows a nonobstructing calculus just above the left ureterovesical junction

Contrast-enhanced CT image of the kidneys shows mild hydronephrosis, perinephric fluid, and delayed enhancement. The perinephric fluid indicates obstruction and correlates with the likelihood of the passage of the stone

Contrast-enhanced CT image of the lower abdomen shows a tiny, obstructing, left ureteral calculus

Magnified nonenhanced CT image of the right kidney shows slightly hyperattenuating renal pyramids in the right kidney despite the mild hydronephrosis

Nonenhanced CT image shows an obstructing right ureteral calculus. A slight rim of soft tissue is noted around the stone (ie, rim sign).

Nonenhanced CT image of the right kidney shows slight perinephric fluid but no stone or hydronephrosis

Contrast-enhanced CT image shows a patchy area of hypoopacity consistent with pyelonephritis.

Nonenhanced CT image of the pelvis shows a small calculus in the bladder near the left ureterovesical junction

Prone nonenhanced CT image shows that the stone in the left ureterovesical junction does not move to the dependent portion of the bladder. This finding indicates that it is still in the distal ureter at the ureterovesical junction and that it has not passed into the bladder.

Contrast-enhanced CT image of the right kidney shows a cluster of calyceal calculi without hydronephrosis

Nonenhanced CT image shows calcification in a calyceal diverticulum. Calyceal diverticula predispose patients to calculus formation as a result of relative stasis of the urine in the diverticula.

Nonenhanced CT image shows nonobstructing right renal calculus, moderate left hydronephrosis, and slight perinephric fluid.

Nonenhanced CT image shows an obstructing left proximal ureteral calculus with a slight soft-tissue rim around the stone (ie, rim sign).