Intravenous Urography: Use and Risks

Abstract

With many modalities in radiographic imaging, Intravenous urography is one of those that are slowly being used less. Due to its patient invasiveness, Computed tomography is starting to take over as the preferred choice in diagnosing pathologies and defects that IUV used to detect. This paper discusses what IVU is, what it does and how it is done, what are the risk, indication and contraindication of this study and why it has slowly faded into the background.

Intravenous Urogram

Intravenous Urogram  (Pyelogram)

Radiographic imaging uses multuiple modalities to help diagnose and prevent pathologies that can affect a human’s well-being.  One of these modalities is Intravenous Urogram (IVU) also known as Intravenous Pyelogram; although Computed Tomography (CT) is slowly replacing this modality, we still can deny the importance of it.

The basic principle of this modality is to inject contrast dye through the veins and into the bloodstream to diagnose and assess any defects in the renal and urinary organs. IVU can also help evaluate abdominal masses, tumors and renal cysts as well as pre-operative evaluation such as location, size ang shape of the kidneys.

Being a slightly invasive radiographic examination IVU has its own contraindications. First and foremost, the radiology tech should be informed if the patients have had past allergic reactions from certain dyes such as Iodine. Other tests such as Glomerular Filtration Rate (GFR) and Blood Urea Nitrogen (BUN) should also be done to see if the kidneys are in good shape to filter and remove the dye from the body. GFR basically shows how one’s kidney is functioning while the BUN can detect how high your creatinine level is which can give you if your kidney has any impairment. Medical history should also be checked before going into this radiology examintaion. Risk factors includes; asthma, diabetes, cardiovascular diseases and multiple myeloma which if combined with the contrast dye can lead to acute renal failure. Blood thinners and other OTC meds such as aspirin and heparin should also be stopped before undergoing examination. It is also advisable not to take Pepto-Bismol beforehand as it contains bismuth that is radio-opaque and can manifest into the radiographic image.

 In the past IVU has been the go to modality used to visualize pathologies that is located in the renal and urinary system. One of the most common pathology that it can detect is urolethiasis; also known as kidney stones that can manifest as calcified rocks on the image and hydronephrosis which is the abnormal clogging of urine into the kidneys due to a blockage in the ureter, causes of which can be an infection, an enlarged prostate, a blood clot, or a tumor. In addition of pathologies, IVU can also be used to detect congenital defect in the kidney. One of these defects is a Horseshoe kidney, also known as renal fusion in that both kidneys faild to separate during the organs development, symptoms of this defect includes; pain in the belly, UTI and nausea.

 As per most of the radiographic examination Patient preparation is also important. The night before the examination, patients are suggested to fast for twelve hours to rid their stomach of food or any other substances that can show itself into the image. A mild laxative can also be ingested to achieve the same effect.

 Radiographic imaging for this modality has a few steps. The first image that needs to be taken is a scout image. A scout view is a preliminary image that is before performing a major portion of a particular modality. There are many reasons to get a scout view: to make sure the region of interest is within the field of view, to check the exposure technique, or as a baseline prior to administration of contrast material. After the scout image, 1ml of the contrast will be injected intravenously to look for any contrast reaction.  When reaction does not happen the rest of the contrast will be rapidly injected within 30-60 seconds. As interval time for this examination varies per hospital protocol it is usually a 5 minutes’ interval for 30 minutes and a post void image is taken after that. First position for these images is with the patient lying supine. After the first interval image has been taken compression bands are applied on a patient’s abdomen to produce better pelviccalyceal distension.10 minutes into the examination, the patient will be instructed to be turn into LPO and RPO positions for the dye to completely fill the kidneys and assess the defects that it has. After 15 minutes the patient will be instructed to be on prone position for the dye to fill the ureters better, when the timed interval images are done, a post void film will be taken to assess bladder mucosal lesions, diverticula, bladder tumor and residual urine. After the examination the patient will be observed for at least 6 hours and to be sure that there is no late contrast reactions, or with high-risk patients- renal function can deteriorate.

IVU has been the go to modality when it comes to the renal and urinary systems, but due to the invasiveness and risks that the study can give, it’s now being phased-out by computed tomography for studies on these said body systems.

References:

• Shetty, A. (n.d.). Intravenous urography: Radiology Reference Article. Retrieved from https://radiopaedia.org/articles/intravenous-urography?lang=us
• Radiological Society of North America, Rsna, & American College of Radiology. (n.d.). IVP - Intravenous Pyelogram. Retrieved from https://www.radiologyinfo.org/en/info.cfm?pg=ivp
• Radiological Society of North America, Rsna, & American College of Radiology. (n.d.). IVP - Intravenous Pyelogram. Retrieved from https://www.radiologyinfo.org/en/info.cfm?pg=ivp
• Intravenous pyelogram. (2018, May 09). Retrieved from https://www.mayoclinic.org/tests-procedures/intravenous-pyelogram/about/pac-20394475
• Intravenous pyelogram. (2018, May 09). Retrieved from https://www.mayoclinic.org/tests-procedures/intravenous-pyelogram/about/pac-20394475