The i.v. pyelogram (synonyms: IVP; intravenous pyelography, intravenous pyelogram; intravenous urography, i.v. urogram; urogram; i.v. urography; excretory urography (AUG); excretory pyelogram) is used for radiographic imaging of the urinary organs or urinary diversion system. An iodine-containing contrast medium is used, which is injected intravenously into the patient. The contrast in the X-ray image is improved so that it can be assessed more clearly. The i.v. pyelogram is always preceded by an abdominal plain radiograph (or abdominal overview radiograph).The following structures or organs can be assessed in the i.v. pyelogram:
- Ren (kidney) – location? Shape? Size? Renal parenchyma? Morphological changes?
- Pelvis renalis (renal pelvis) – concretions? (e.g., kidney stones) Morphological changes?
- Ureter (ureter) – stenosis? (narrowing) Morphologic changes? Displacement of the ureter?
- Vesica (urinary bladder) – location? Shape? Size? Morphological changes?
- Urethra (urethra) – stenosis? Morphological changes?
Optionally, a so-called infusion urogram can be performed, which differs from the i.v. pyelogram by a larger amount of contrast medium and achieves better contrast in the case of impaired renal function. When imaging renal stones, computed tomography is more appropriate.
Indications (areas of application)
- Inflammatory diseases of the urinary organs
- Malformations and anomalies of the renal and/or urinary tract system (ureter and urinary bladder).
- Urinary retention
- Preoperative assessment of the course of the ureter (ureteral course), for example, before gynecological surgery.
- Urolithiasis (urinary stone disease) or stone-related diseases of the urinary organs.
- Tumorous diseases of the urinary organs
- Cysts (cavities)
Contraindications
- Acute renal colic
- Decompensated heart failure (cardiac insufficiency)
- Hyperthyroidism (hyperthyroidism)
- Manifest tetany – seizure-like disturbance of motor function and sensitivity in the presence of hyperexcitability of muscular nerves.
- Renal insufficiency (kidney weakness).
- Contrast agent allergy
- Plasmocytoma – malignant tumor disease from the group of non-Hodgkin’s lymphomas. Its origin is in the lymphoid tissue, as in all lymphomas; many (multiple) tumor foci in the bone marrow (myelomas) are characteristic. Plasmocytoma arises from the degeneration of a single plasma cell.
- Poor general condition of the patient
The procedure
Before performing an i.v. pyelogram, the patient should be pretreated with an oral laxative and a deflating substance. In addition, he should not consume fatty or flatulent foods. First, a native radiograph (abdominal voiding radiograph) of the abdomen or urinary system is performed while the patient is lying down. The second step is intravenous application of an iodine-containing contrast agent (300 mg/ml iodine). The dosage is 1 ml per kilogram of body weight. It is recommended to test the patient’s tolerance to the contrast agent by a trial application with a small amount beforehand. Approximately 10-15 minutes after the end of the contrast medium infusion, the first X-ray image is taken. Particular attention is paid to complete imaging of the kidneys so that renal function can be assessed. The second image is taken after 20 minutes and is used to visualize the ureters (ureters) and the urinary bladder, and the patient should empty his bladder beforehand. If satisfactory contrast is not obtained at the time of the second image, late images (1, 2, 4, 8, 16 h thereafter) can be obtained. Oblique or overview radiographs and slice radiographs can be obtained for special issues. This is followed by evaluation of the radiographs:
- Renal – Excretion of contrast through the kidneys should be contemporaneous and timely. Changes in the renal calices may indicate pathologic (disease) processes: Absence of calices? (anomalies of anlage); calyx elongation? (enlargement of the calyx system due to a tumor or cyst); calyx plumping as a sign of inflammation? Other possible findings include hydronephrosis (congestive kidney), positional anomalies (e.g., pelvic kidney), or a double renal anlage.
- Ureters – The ureters are not visible on the pyelogram pysiologically because fluid is transported in waves to the urinary bladder. A ureter filled with contrast may indicate obstruction (narrowing) or abnormality. If the position of the ureters is displaced, it may indicate a mass or inflammatory process. Contrast gaps in the ureter, for example, are a sign of ureteral stones.
- Urinary bladder – In the urinary bladder, stones or tumors can also cause a contrast cavity. Elevation of the bladder floor may indicate a process in the prostate (eg, prostatic hyperplasia (prostate enlargement); prostate cancer – prostate cancer).
Variants of i.v. pyelography include retrograde pyelography and compression pyelography. In retrograde pyelography, the contrast agent is applied cystoscopically (using a thin catheter inserted into the bladder) through the ostium of the ureters (confluence of the ureter). The contrast medium retrogradely fills the renal pelvis. Retrograde pyelography is rarely used because of the risk of germ carriage with subsequent renal pelvic inflammation. In addition, the catheter may cause injury to the urinary drainage system. Compression pyelography is a normal pyelography, while the abdomen (belly) is compressed so that the contrast medium runs off more slowly. This is done with the help of a rubber bellows that is inflated with a pressure of 20-40 cm H2O.
