Imaging in Urology

Imaging Modalities

• Plain film imaging (Radiography)• Plain film of the abdomen (KUB)• Urography• Ultrasonography• Computed tomography• Magnetic resonance imaging• Radionuclide imaging

Plain Film Imaging

• Uses x-rays to develop an image on a piece of film based on the amount of energy that passes through the object between the source and the film plate– Tissues of the body and foreign or organic

materials that may be found within the body absorb different amounts of radiation to create a readable image

– Contras media can be used for a more precise evaluation of the urinary tract

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

Plain Film of the Abdomen (KUB)

• The kidneys-ureters-bladder (KUB) is often the first imaging study performed to visualize the abdomen and urinary tract– The film is taken with the patient supine and

should include the entire abdomen from the base of the sternum to the pubic symphisis

– Can show bony abnormalities, calcification and large soft tissue masses

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

Urography

• Involves instillation of contrast material to better visualize the collecting or lumenal structures of the kidneys, ureters, bladder, and urethra– This can be done after IV injection or direct

instillation into the urinary tract1) Intravenous urography2) Cystography3) Voiding cystourethroography4) Retrograde urethrography

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

Intravenous Urography

• IVU/ intravenous pyelogram is the classic modality of imaging the entire urethelial tract from pyelocalyceal system trhough the ureters and bladder– Excellent for indentifying small urethelial lesions

as well as the severity of obstruction from calculi– Provides anatomical and qualitative functional

information about the kidneys

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

Cystography

• Permits imaging of an opacified urinary bladder after retrograde instillation of contrast media through a urethral or suprapubic catheter– Imaging is performed to demonstrate a suspected

urine leak, either from traumatic bladder rupture or after bladder surgery

– Can also demonstrate a presence of a fistula between the bladder and vagina or to characterize bladder diverticuli

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

Voiding Cystourethrography

• Can be used to evaluate for abnormal anatomy and function of the lower urinary tract in both children and adults– Similar to the cystogram, instillation of contrast

media into the bladder through a urethral cahteter is also employed

– After full distention of the bladder, the patient is instructed to void either after removing the catheter or around the catheter

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

Retrograde Urethrography

• Complete evaluation of the urethra includes both antegrade and retrograde urethrography– Allows visualization of the anterior male urethra – Used for evaluating a suspected traumatic

urethral injury or urethral stricture– Can also be useful for diagnosis of a urethral

diverticulum in females

Potts, J. (2004). Essential Urology: A Guide to Clinical Practice. Humana Press Inc.

MRI

• Can be generally used in place of a CT scan when renal insufficiency or contrast allergy prohibits the use of CT scan

• The process by which the protons realign themselves with the magnetic field is referred to as relaxation. The protons undergo 2 types of relaxation: T1 (or longitudinal) relaxation and T2 (or transverse) relaxation

MRI• In T1-weighted images (emphasizing the difference in T1

relaxation times between different tissues), water-containing structures are dark. T1-weighted images do not show good contrast between normal and abnormal tissues. However, they do demonstrate excellent anatomic detail.

• T2-weighted images emphasize the difference in T2 relaxation times between different tissues. Because water is bright in these images, T2-weighted images provide excellent contrast between normal and abnormal tissues, although with less anatomic detail than T1-weighted images

MRI

CT Scan• Study of choice for the general imaging of the kidney

and ureter• used to create cross-sectional images of structures in

the body. In this procedure, x-rays are taken from many different angles and processed through a computer to produce a three-dimensional (3-D) image

• Uptake of contrast by renal parenchyma during nephrogram phase provides rough estimate of kidney function

• Useful when renal of ureteral malginancy is suspected

CT Scan• often used examine structures

in the abdomen and pelvis (reproductive organs, liver, pancreas, gallbladder, spleen and intestines). CAT Scans are a diagnostic tool that urologists use to detect and diagnose: recurrent urinary tract infections, sources of blood in the urine (hematuria), kidney stones, renal cysts and masses. Moreover, it can help urologists rule out prostate, bladder and renal cancers

Nuclear Medicine

• uses the radiation released by radionuclides (called nuclear decay) to produce images

• A radionuclide, usually technetium-99m, is combined with different stable, metabolically active compounds to form a radiopharmaceutical that localizes to a particular anatomic or diseased structure (target tissue).

• tracer goes to the target organ and can then be imaged with a gamma camera, which takes pictures of the radiation photons emitted by the radioactive tracer