Overview of IVP
This test could be more accurately called "IVU," or intravenous urogram, but most have accepted the old-fashioned term, IVP. IVPs are basically x-rays of the urinary tract. Because the kidneys, ureters (the tubes that connect the kidneys with the bladder), and the bladder blend in with other soft tissues in the abdomen, they are not easily visible on regular x-rays. To see them better, dye (contrast material) must be injected into a vein. After the dye is excreted through the kidneys, excellent pictures of the various components of the kidneys, ureters, and bladder can be obtained.
When Is an IVP Necessary?
Before the advent of CT scan and ultrasound, IVP was essentially the only study that allowed radiologists to evaluate the upper urinary tract. Now, because of the newer technologies, there are fewer conditions that require intravenous urography. These include flank pain and blood in the urine (hematuria), which may suggest the passage of a stone through the ureter, and other circumstances that require an overall look at the entire urinary tract from the kidneys to the bladder.
Alternatives to IVP
CT scan, ultrasound, and MRI scan have taken over much of the role played traditionally by IVPs. Ultrasound requires no dye and involves no radiation. MRI does not involve radiation but is expensive.
There is no universal agreement here. Some radiology departments require some sort of bowel preparation the day before. It is important that you show up with nothing in your stomach, having taken nothing by mouth (NPO) for at least 4 hours. The reason for this will become more apparent as you read on. This does not mean that you could not have the dye if you had just eaten. Radiologists do that in emergency situations all the time, in which case they have to be a bit more careful.
Risks and Potential Complications of IVP
An IVP involves intravenous injection of iodinated dye. Those who have known allergies to iodine are apt to have allergic reactions that can vary from mild to severe. In some cases, the blood pressure drops and emergency resuscitative measures are needed. In reality, reactions of any serious nature are quite rare.