An aberrant course of the distal ureter can pose a risk of ureteral injury during surgery for inguinal hernia repair and other groin operations. In a recent case series of inguinoscrotal hernation of the ureter, we found that each affected ureter was markedly anterior to the psoas muscle at its mid-point on abdominal CT.
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The ureter itself has a normal appearance at CT despite the abnormality in its most proximal segment. The key feature in identifying this abnormality is proximal dilatation of the renal pelvis and calices.
Pathologic ureteral conditions can manifest as one or more of the following findings at CT urography: congenital abnormality, filling defect, dilatation, narrowing, or deviation in course. The initial nonenhanced phase is included to identify urinary tract calculi or a hyperdense clot and to determine if a lesion enhances.
Nonenhanced CT is therefore the preferred modality for diagnosing ureteral calculi, and CT urography is not generally indicated. Nonetheless, calculi are occasionally seen at CT urography. Figure 10a Obstructing calculus in a 57-year-old man with hematuria.
Tumors appear as small filling defects in the contrast-filled ureter or as circumferential thickening of the wall of the ureter on CT urography ( Fig. 15.20 ). The part of the ureter proximal to the tumor may be dilated. Calcified ureteral TCC may be mistaken for calculi.
A CT urogram is used to examine the kidneys, ureters and bladder. It lets your doctor see the size and shape of these structures to determine if they're working properly and to look for any signs of disease that may affect your urinary system.
Symptoms of a blocked ureter or urinary tract obstruction include:Pain in your abdomen, lower back or sides below your ribs (flank pain).Fever, nausea or vomiting.Difficulty urinating or emptying your bladder.Frequent urination.Recurring urinary tract infections (UTI).Urine that is bloody or cloudy.More items...•
Ureteral obstruction can lead to urinary tract infections and kidney damage, which can be irreversible.
Urinary tract obstruction is a blockage that inhibits the flow of urine through its normal path (the urinary tract), including the kidneys, ureters, bladder, and urethra. Blockage can be complete or partial. Blockage can lead to kidney damage, kidney stones, and infection.
Drainage procedures. A ureteral obstruction that causes severe pain might require an immediate procedure to remove urine from your body and temporarily relieve the problems caused by a blockage. Your doctor (urologist) may recommend: A ureteral stent, which is a hollow tube inserted inside the ureter to keep it open.
A kidney stone usually will not cause symptoms until it moves around within your kidney or passes into your ureters — the tubes connecting the kidneys and the bladder. If it becomes lodged in the ureters, it may block the flow of urine and cause the kidney to swell and the ureter to spasm, which can be very painful.
Ureteral Trauma The ureters are tubes made of muscle to move urine from the kidneys to the bladder. If one or both are damaged, you will need surgery to repair them. If there is a limited tear to the ureters, stents or surgery can fix the tear.
If a ureter stone is small, it will cause no symptoms. If it is large enough to become an obstruction, it will block the flow of urine and become extremely painful, accompanied by cramping in the kidney area and lower abdomen, which may later spread to the groin.
The most frequent site is the junction of the ureter and the renal pelvis. An obstruction of this nature is symptomless and difficult to diagnose; consequently, a great deal of damage can be done to the kidneys before it is discovered.
Symptoms and Causes However, stones that block the ureter or any of the kidney's drainage tubes may cause symptoms that include: Severe, intermittent (comes and goes) pain in the upper flank (in the back, under the lower ribs) that can radiate (spread) to the lower abdomen, and; Nausea and vomiting.
Ureteritis is a medical condition of the ureter that involves inflammation. One form is known as "ureteritis cystica".
A common type of ureteral stricture is ureteropelvic junction, or UPJ, obstruction. A UPJ obstruction is often congenital, but sometimes it is a result of an injury incurred during surgery or due to surgical scarring. It can also be caused by kidney stones, upper urinary tract inflammation, or a tumor.
Over the past decade, computed tomographic (CT) urography has emerged as the primary imaging modality for evaluating the urinary tract in various clinical settings ( 1 – 4 ). CT urography not only allows detailed assessment of the urinary tract but also enables direct visualization of adjacent structures and comprehensive evaluation of the abdomen and pelvis. CT urography is currently the first-line imaging modality for several indications, including hematuria, initial staging of urothelial tumors, and follow-up surveillance in patients with prior urothelial tumors ( 5 – 9) ( Table 1 ). CT urography has essentially replaced intravenous urography as the first-line imaging modality in most of these settings and has been shown to have increased overall accuracy and sensitivity, particularly for evaluation of hematuria ( 7, 10 – 12 ). Additional indications for CT urography include evaluation of urinary tract obstruction, depiction of complex congenital or postsurgical urinary tract anatomy, and any clinical scenarios where comprehensive evaluation of the urinary tract is needed ( 3, 13 ). In this review, we focus specifically on ureteral abnormalities that can be identified at CT urography.
In the most general sense, complete CT urography includes a nonenhanced phase, a contrast-enhanced phase, and an excretory phase ( Fig 1 ). Several imaging protocols are currently used in clinical practice, some of which allow a decreased radiation dose ( Table 2 ). The triple-phase technique includes separate nonenhanced, contrast-enhanced, and excretory phases ( Fig 1 ). The split-bolus technique combines the contrast-enhanced and excretory phases into a single phase, thereby reducing the radiation dose with a total of two acquisition phases instead of three ( 14 ). Local practices vary in terms of the specific contrast-enhanced phase (s) used in the triple-phase and split-bolus techniques, which may include a corticomedullary phase or a nephrographic phase. At our institution, we have implemented a split-bolus technique with a combined nephrographic-pyelographic phase.
Ureteral calculi are the most common cause of ureteral filling defects ( Fig 10 ). Historically, the description of calculi as “filling defects” has applied to intravenous urography, where a calculus is seen as a defect in the contrast column. However, at CT, all urinary tract calculi have high attenuation and measure more than 200 HU (with the rare exception of indinavir calculi, which have soft-tissue attenuation). As a result, calculi are often obscured by the high attenuation of excreted contrast agent at CT urography and may not be identified as filling defects. Nonenhanced CT is therefore the preferred modality for diagnosing ureteral calculi, and CT urography is not generally indicated. Nonetheless, calculi are occasionally seen at CT urography.
Males do not present with incontinence because the ectopic ureter inserts above the level of the external urethral sphincter ( 24 ). Males with an ectopic ureter commonly present with a urinary tract infection. Figure 6a Complete ureteral duplication with a ureterocele in a 63-year-old man.
However, by far the most common causes of filling defects are calculi, tumors such as UCC, and clots. Calculi are readily identified at nonenhanced CT as radiodense foci along the course of the ureter.
Normal Ureter. The ureter is a muscular conduit that carries urine from the renal pelvis to the urinary bladder. It arises proximally from the renal pelvis at the ureteropelvic junction ( UPJ) and empties distally into the urinary bladder at the ureterovesicular junction ( UVJ) ( Fig 3 ).
UCC, or transitional cell carcinoma, is the most common type of uroepithelial tumor. It can occur anywhere in the urinary tract, most commonly in the urinary bladder and second most commonly in the renal pelvis. UCC of the ureter is uncommon, but when it does occur, the distal ureter is the most frequent site ( 8 ). The varied growth patterns include papillary, which causes filling defects ( Fig 12 ), and infiltrating, which may cause wall thickening or strictures. Occasionally, there may be an associated “goblet” sign, which is defined as a cup-shaped collection of contrast agent distal to a ureteral filling defect. The goblet sign is highly suggestive of UCC but not necessarily specific ( Fig 12a) ( 36 ). In such cases, the slow-growing polypoid tumor in the lumen causes gradual dilatation of the immediately proximal and distal ureteral segments. Distal propulsion of the mass during peristalsis further contributes to distal dilatation. Of note, the goblet sign specifically refers to the distal cup-shaped collection of contrast agent relative to the filling defect. Proximal dilatation may also be present, particularly if the tumor is obstructing, but this finding should not be described as the goblet sign, even if it is cup shaped.
CT Scans. A CT scan can provide a better view of the urinary tract. This test uses X-rays and a computer to create cross-sectional, three-dimensional images. The doctor may give you a contrast agent, or dye, by injection. This enhances the image.
This enhances the image. The information provided by a CT scan helps the doctor decide the cause, location, and extent of the stricture. It can also help the doctor to decide on the best approach to treatment.
Retrograde Ureteroscopy. A retrograde ureteroscopy uses X-rays and a contrast dye injected into the ureter to determine if something is blocking the urinary tract. During this procedure, a doctor inserts a thin, flexible tube called a ureteroscope into the urethral opening, passing it through the bladder to the ureter.
NYU Langone urologists are experts in diagnosing ureteral stricture, which is a narrowing of one of the ureters—tubes that carry urine from each kidney to the bladder. This narrowing causes an obstruction in the flow of urine.
A renal scan of the urinary tract is a test used to evaluate kidney function and determine the extent of ureter obstruction. A renal scan is a nuclear imaging test that reveals how long it takes for urine to flow from the kidneys to the bladder. The test is very effective in identifying obstructions in the urinary tract, as well as measuring the function of the affected kidney.
Ultrasound. Your doctor may recommend that you have an ultrasound test, which uses sound waves to produce images on a high definition monitor. The results can help to establish whether the kidneys are enlarged due to a stricture. The images may also identify blockages in the ureters leading to and from the kidneys.
In MRI scans, a magnetic field and radio waves are used to create two- and three-dimensional images of organs and tissues in the body. This test helps NYU Langone doctors to view the urinary tract and rule out other causes of urinary obstruction, such as a tumor, and can help the doctor determine what type of treatment is best.
The conticomedullary phase typically occurs approximately 30 to 70 seconds after the contrast bolus; the nephrogram phase is seen 80 to 120 seconds after the contrast bolus; the excretory phase begins about 3 minutes after injection and can last 15 minutes or longer. 2-dimentional and 3-dimentional reformations may be useful in defining certain types of renal abnormalities, such as renal cell carcinoma and ureteropelvic junction UPJ obstruction.
Most of the renal abnormalities are best seen on CT after intravenous contrast media administration. Plain CT scan is generally reserved to demonstrate calcification and calculi that may be obscured by contrast agent or it is used as a baseline of attenuation measurement when contrast enhancement is calculated as a feature of renal mass characterization. MDCT is the current modality of choice for renal evaluation.
Before your CT urogram, a member of your health care team will: Ask you questions about your medical history. Check your blood pressure, pulse and body temperature. Ask you to change into a hospital gown and remove jewelry, eyeglasses and any metal objects that may obscure the X-ray images.
Why it's done. A CT urogram is used to examine your kidneys, ureters and bladder. It lets your doctor see the size and shape of these structures to determine if they're working properly and to look for any signs of disease that may affect your urinary system. Your doctor may recommend a CT urogram if you're experiencing signs ...
To keep the images from blurring, you'll be asked to hold your breath for a few seconds during the scanning. After the CT urogram is complete, you'll be asked to wait while the technologist ensures the images are good enough quality for an accurate evaluation.
For a CT urogram, you usually lie on your back on an exam table, though you may be asked to lie on your side or stomach. Straps and pillows may be used to help you maintain the correct position and keep still during the exam. You may be asked to change positions during the CT urogram.
You may feel a warm, flushed sensation when the dye is injected, and a metallic taste may appear in your mouth for a minute or two. The contrast material may briefly make you feel like you have to urinate.
Straps and pillows may be used to help you maintain the correct position and keep still during the exam. You may be asked to change positions during the CT urogram. An IV line will be placed into a vein in your hand or arm through which the X-ray dye will be injected.
If you are pregnant or think that you may be pregnant, tell your doctor before having a CT urogram. Though the risk to an unborn baby is small, your doctor may consider whether it's better to wait or to use another imaging test.
The ureter passes through the apex of the cone of the perirenal space as it courses to the pelvis. The posterior pararenal space is a potential space, occupied only by fat, blood vessels, and lymphatics, extending from the posterior renal fascia to the transversalis fascia.
The kidneys are covered by a tight fibrous capsule that produces a sharp margin defined by perirenal fat on CT. The perirenal fat extends into the renal sinus, outlining blood vessels and the renal collecting system. Connective tissue septa extend between the fibrous capsule of the kidney and the renal fascia.
The features that must be evaluated to characterize a renal mass are the presence and type of calcification, attenuation of the mass before and after contrast medium administration, the margin of the mass with the kidney and with surrounding tissues, and the presence and thickness of septa and the thickness of the wall of cystic masses. Artifactual pseudoenhancement, related to a beam-hardening effect from iodinated contrast medium, may increase attenuation of lesions by up to 10 Hounsfield units (HU). Attenuation must increase by a minimum of 20 HU following bolus intravenous contrast medium administration to be considered enhancement. An increase in attenuation of less than 10 HU is not considered enhancement. An increase in attenuation of 10 to 20 HU is equivocal enhancement.
The anterior layer of the posterior renal fascia is continuous with the anterior renal fascia. The posterior layer of the posterior renal fascia is continuous with the lateroconal fascia, forming the lateral boundary of the anterior pararenal space.
The renal arteries and veins can be identified from the great vessels to the kidneys. The right renal artery courses behind the vena cava. The right renal vein extends anterior to the right renal artery directly from the right kidney to the vena cava.
The most common sites are the lungs (50%–60%), mediastinum, bone, liver, contralateral kidney or adrenal gland , and brain. •. Late metastases (>10 years after surgery) are most common to lung, pancreas, bone, skeletal muscle, and bowel. Surgical resection of isolated late metastases may be curative.