| Pyelogram | |
|---|---|
| ICD-9 | 87.73,87.74,87.75 |
| MeSH | D014567 |
| OPS-301 code | 3-13d |
Pyelogram (orpyelography orurography) is a form of imaging of therenal pelvis andureter.[1]
Types include:
| Pyelogram | |
|---|---|
 An Example of an IVU radiograph | |
| Specialty | Radiology |
| ICD-9-CM | 87.73 |
| OPS-301 code | 3-13d.0 |
Anintravenous urography (IVU), also called anintravenous urogram or simplyurogram, is aradiological procedure used to visualize abnormalities of theurinary system, including thekidneys,ureters, andbladder. Unlike akidneys, ureters, and bladder x-ray (KUB), which is a plain (that is, noncontrast) radiograph, an IVP usescontrast to highlight theurinary tract.
In IVP, thecontrast agent is given through a vein (intravenously), allowed to becleared by the kidneys andexcreted through the urinary tract as part of theurine.[5] If this iscontraindicated for some reason, aretrograde pyelogram, with the contrast flowing upstream, can be done instead.
An intravenous pyelogram is used to look for problems relating to the urinary tract.[5] These may include blockages or narrowing, such as due to kidney stones, cancer (such asrenal cell carcinoma ortransitional cell carcinoma),enlarged prostate glands, and anatomical variations,[5] such as amedullary sponge kidney.[6] They may also be able to show evidence of chronic scarring due to recurrent urinary tract infections,[5] and to assess for cysts[6] associated with polycystic kidney disease.
An injection of X-raycontrast medium is given to a patient via a needle orcannula into thevein,[7] typically in the antecubital fossa of the arm. The contrast isexcreted 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.[7] At the end of the test, a person is asked to pass urine and a final X-ray is taken.[7]
Before the test, a person is asked to pass urine so that their bladder is emptied.[5] They are asked to lie flat during the procedure.[7]
Immediately after the contrast is administered, it appears on an X-ray as a 'renal blush'. This is the contrast being filtered through the cortex. At an interval of 3 minutes, the renal blush is still evident (to a lesser extent) but the calyces andrenal pelvis are now visible. At 9 to 13 minutes the contrast begins to empty into theureters and travel to thebladder which has now begun to fill. To visualize the bladder correctly, a post micturition X-ray is taken, so that the bulk of the contrast (which can mask a pathology) is emptied.
An IVP can be performed in either emergency or routine circumstances.
This procedure is carried out on patients who present to an Emergency department, usually with severerenal colic and a positivehematuria test. In this circumstance the attending physician requires to know whether a patient has a kidney stone and if it is causing any obstruction in the urinary system.
Patients with a positive find forkidney stones but with no obstruction are sometimes discharged based on the size of the stone with a follow-up appointment with a urologist.
Patients with a kidney stoneand obstruction are usually required to stay in hospital for monitoring or further treatment.
An Emergency IVP is carried out roughly as follows:
If no obstruction is evident on this film a post-micturition film is taken and the patient is sent back to the Emergency department. If an obstructionis visible, a post-micturition film is still taken, but is followed up with a series of radiographs taken at a "double time" interval. For example, at 30 minutes post-injection, 1 hour, 2 hours, 4 hours, and so forth, until the obstruction is seen to resolve.This is useful because this time delay can give important information to the urologist on where and how severe the obstruction is.
This procedure is most common for patients who have unexplained microscopic or macroscopic hematuria. It is used to ascertain the presence of a tumour or similar anatomy-altering disorders. The sequence of images is roughly as follows:
At this point, compression may or may not be applied (this is contraindicated in cases of obstruction).
In pyelography, compression involves pressing on the lower abdominal area, which results in distension of the upper urinary tract.[8]
The kidneys are assessed and compared for:
The ureters are assessed and compared for:
The bladder is assessed for:
Intravenous pyelograms useionizing radiation, which involves risk to healthy tissues (potentially encouraging cancer orrisking birth defects).[5] Therefore, they are often now replaced byultrasonography andmagnetic resonance imaging (MRI). Also, theiodinated contrast medium used in contrast CT and contrast radiography can causeallergic reactions, includingsevere ones.[5] The contrast dye may also betoxic to the kidneys.[7] Because a cannula is inserted, there is also a risk of acannula site infection, that may cause fevers or redness of the cannula area.[7]
| Antegrade pyelography, anterograde pyelography | |
|---|---|
 Antegrade pyelogram of grade IIIhydronephrosis with obstruction at theureterovesical junction due to bladderendometriosis in a 29 year old female. The tip of the nephrostomy is located in an inferiorcalyx. | |
| Purpose | visualize the upper collecting system of the urinary tract |
Antegrade pyelography is the procedure used to visualize the upper collecting system of the urinary tract, i.e.,kidney andureter.It is done in cases where excretory orretrograde pyelography has failed or contraindicated, or when anephrostomy 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 andX-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.[11][12]
| Pyelogram | |
|---|---|
| ICD-9 | 87.74 |
| OPS-301 code | 3-13d.5 |
Aretrograde pyelogram is amedical imaging procedure in which aradiocontrast agent is injected into theurethra in order to visualize the urinary bladder, ureter,bladder, andkidneys withfluoroscopy orradiography, using plainX-rays.[13] The flow of contrast (up from the bladder to the kidney) is opposite the usualoutbound flow of urine, hence theretrograde ("moving backwards") name.
A retrograde pyelogram may be performed to find the cause ofblood 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.[13] It can also be usedureteroscopy, or to delineate renal anatomy in preparation for surgery. Retrograde pyelography is generally done when an intravenousexcretory study (intravenous pyelogram or contrastCT scan) cannot be done because ofrenal disease or allergy to intravenous contrast.
Relative contraindications include the presence of infected urine, pregnancy (because of radiation), or allergy to the contrast.[13] Because a pyelogram involves cystoscopy, it may cause sepsis, infection or bleeding,[13] and may also cause nausea and vomiting.[13] The dye may also betoxic to the kidneys.[13]
Before the procedure, a person is usually asked to complete a safety check assessing for potential risks, such as pregnancy or allergy.[13] They may be asked to take an enema, and not to eat for some hours.[13] An intravenous drip is inserted and a person is given some sedation before a cystoscope, which is a flexible tube, is inserted into the bladder via the urethra.[5] 10 ml of contrast[14] is usually injected duringcystoscopy, which is where a flexible tube is inserted into the bladder and to the lower part of the ureter.[5]Fluoroscopy, or dynamic X-rays, is typically used for visualization. The procedure is usually done under general or regionalanesthesia.[13]
Risks of complications of the procedure includes: pyelosinus extravasation (contrast going intorenal sinus) and pyelotubular (contrast going intocollecting duct) reflux of contrast due to overfilling of the urinary system. It can cause pain, fever and chills. Infection may be accidentally introduced into the urinary tract. There can be also damage or perforation of renal pelvis or ureter.[14] Rarely,acute renal failure can occur.[15]
Depending on the outcome and diagnosis following an IVP, treatment may be required for the patient. These includesurgery,lithotripsy,ureteric stent insertion andradiofrequency ablation. Sometimes no treatment is necessary as stones <5mm can be passed without any intervention.
IVP is an affordable and usefulimaging modality and continues to be relevant in many parts of the world. In the developed world, however, it has increasingly been replaced by contrastcomputed tomography of the urinary tract (CT urography), which gives greater detail of anatomy and function.[5]
The technique of IVP was originally developed byLeonard Rowntree of theMayo Clinic in the 1920s.[16] 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.[17] Because of increased accuracy, computed tomography and ultrasounds of the renal tract are now used; ultrasounds additionally do not involve radiation.[6]
Etymologically, urography iscontrast radiography of theurinary tract (uro- +-graphy), and pyelography is contrast radiography of therenal pelvis (pyelo- +-graphy), but in present-day standard medicalusage, they aresynonymous.
