Pyelogram

An intravenous urography (IVU), also called an intravenous urogram or simply urogram, is a radiological procedure used to visualize abnormalities of the urinary system, including the kidneys, ureters, and bladder. Unlike a kidneys, ureters, and bladder x-ray (KUB), which is a plain (that is, noncontrast) radiograph, an IVP uses contrast to highlight the urinary tract. In IVP, the contrast agent is given through a vein (intravenously), allowed to be cleared by the kidneys and excreted through the urinary tract as part of the urine. If this is contraindicated for some reason, a retrograde pyelogram, with the contrast flowing upstream, can be done instead. Uses An intravenous pyelogram is used to look for problems relating to the urinary tract. They may also be able to show evidence of chronic scarring due to recurrent urinary tract infections, typically in the antecubital fossa of the arm. The contrast is excreted or removed from the bloodstream via the kidneys, and the contrast media becomes visible on X-rays almost immediately after injection. X-rays are taken at specific time intervals to capture the contrast as it travels through the different parts of the urinary system. • If compression is applied: a 10 minutes post-injection X-ray of the renal area is taken, followed by a KUB on release of the compression. • If compression is not given: a standard KUB is taken to show the ureters emptying. This may sometimes be done with the patient lying in a prone position. • A post-micturition X-ray is taken afterwards. This is usually a coned bladder view. Image assessment The kidneys are assessed and compared for: • Regular appearance, smooth outlines, size, position, equal filtration and flow. The ureters are assessed and compared for: • Size, a smooth regular and symmetrical appearance. A 'standing column' is suggestive of a partial obstruction. The bladder is assessed for: • Regular smooth appearance and complete voiding. Risks Intravenous pyelograms use ionizing radiation, which involves risk to healthy tissues (potentially encouraging cancer or risking birth defects). • Contrast allergy: If the patient has any previous history of adverse or moderate reactions to contrast medium. • Patient with significantly decreased kidney function;because contrast media can be nephrotoxic and worsen kidney function ==Anterograde pyelogram==

Antegrade pyelography is the procedure used to visualize the upper collecting system of the urinary tract, i.e., kidney and ureter. It is done in cases where excretory or retrograde pyelography has failed or contraindicated, or when a nephrostomy tube is in place or delineation of upper tract is desired. It is commonly used to diagnose upper tract obstruction, hydronephrosis, and ureteropelvic junction obstruction. In this, radiocontrast dye is injected into the renal pelvis and X-rays are taken. It provides detailed anatomy of the upper collecting system. As it is an invasive procedure, it is chosen when other non-invasive tests are non confirmatory or contraindicated and patient monitoring is required prior and after the procedure. ==Retrograde pyelogram==

A retrograde pyelogram is a medical imaging procedure in which a radiocontrast agent is injected into the urethra in order to visualize the urinary bladder, ureter, bladder, and kidneys with fluoroscopy or radiography, using plain X-rays. The flow of contrast (up from the bladder to the kidney) is opposite the usual outbound flow of urine, hence the retrograde ("moving backwards") name. A retrograde pyelogram may be performed to find the cause of blood in the urine, or to locate the position of a stone or narrowing, tumour or clot, as an adjunct during the placement of ureteral stents. Rarely, acute renal failure can occur. ==Treatment==

Depending on the outcome and diagnosis following an IVP, treatment may be required for the patient. These include surgery, lithotripsy, ureteric stent insertion and radiofrequency ablation. Sometimes no treatment is necessary as stones <5mm can be passed without any intervention. ==Future==

IVP is an affordable and useful imaging modality and continues to be relevant in many parts of the world. In the developed world, however, it has increasingly been replaced by contrast computed tomography of the urinary tract (CT urography), which gives greater detail of anatomy and function. ==History==

The technique of IVP was originally developed by Leonard Rowntree of the Mayo Clinic in the 1920s. IVP was previously the test of choice for diagnosing ureter obstruction secondary to urolithiasis but in the late 1990s non-contrast computerized tomography of the abdomen and pelvis replaced it because of its increased specificity regarding etiologies of obstruction. Because of increased accuracy, computed tomography and ultrasounds of the renal tract are now used; ultrasounds additionally do not involve radiation. Etymologically, urography is contrast radiography of the urinary tract (uro- + -graphy), and pyelography is contrast radiography of the renal pelvis (pyelo- + -graphy), but in present-day standard medical usage, they are synonymous. ==See also==