direct urinary system radiographs
• It is the first imaging method in the diagnosis of urinary system stones.
Intravenous pyelography (IVP)
Ionic or non-ionic water-soluble iodinated contrast material is given. Nowadays, non-ionic forms are used mostly due to their low toxicity and osmolarity.
Before administering the contrast agent by IV route, direct urinary system radiographs is taken and opaque stones, if any, gas distribution in the abdomen and bone structures are demonstrated.
Postcontrast radiograms are used for the filtration functions of the kidneys, the more precise localization of opacities seen on direct radiographs, the evaluation of nonopaque stones, and the evaluation of the renal parenchyma.
IVP Indications
Infection
Hematuria
Kidney tumors
Renovascular hypertension
Kidney transplant follow-up
Bladder neuromuscular disorders
Congenital anomalies
Surgical complication follow-up
Differential diagnosis in hydronephrosis
IVP contraindications
Iodine allergy
Thyrotoxicosis
Multiple Myeloma
pregnancy
Severe renal and cardiac failure
Alternatives to IVP
MRI urography
1. It is an alternative since iodinated contrast is not used in renal dysfunction.
2. It can demostrate kidney, ureter and bladder masses.
CT irography
1. It can show non-opaque stones.
2. It can show kidney, ureter and bladder masses.
Computed Tomography
The gold standard imaging for stone is non-contrast CT.
Radiation is its most important disadvantage.
Ultrasonography
Non-invasive
Operator dependent (requires experience, it is subjective)
It is frequently used in the evaluation of kidney stones.
Not useful for ureteral stones.
Evaluate hydronephrosis.
Antegrade Pyelography
It is used in obstructive uropathies.
It is entered into the renal collecting system by percutaneous route.
It is mostly used for therapeutic catheter placement.
urethrography
Retrograde urethrography: It is used in the evaluation of trauma, bladder and urethral injury, and changes secondary to infection.
VCUG : Voiding Cystourethrogram: After the bladder is catheterized, the bladder is filled with a mixture of saline + iodinated contrast material, and images are taken during micturition. Its main indication is vesicoureteral reflux.
It is useful in the diagnosis of ectopic ureter and posterior urethral valve.
Radionuclide imaging
It gives functional and morphological information. The most commonly used radiopharmaceuticals for kidney scintigraphy are Technetium-99m-labeled diethylenetriaminepentaacetic acid (DTPA), dimercaptosuccinic acid (DMSA).
DTPA is excreted by the kidney by glomerular filtration. It is used to evaluate kidney perfusion and pelvicalyceal system and to calculate glomerular filtration rate. DTPA scintigraphy is a dynamic examination and gives information about kidney functions and GFR.
DMSA scintigraphy is a static imaging method used to show renal scar tissue with more anatomy. Scintigraphy can also be used to detect rejection in renal transplantation.