Ultrasonography is a versatile and relatively inexpensive imaging
modality that has the unique feature of being the only imaging modality
to provide real-time evaluation of urologic organs and structures
without the need for ionizing radiation.
• All ultrasound imaging is the result
of the interaction of sound waves
with tissues and structures within the
• Ultrasound waves are produced by
applying short bursts of alternating
electrical current to a series of
crystals housed in the transducer.
• A portion of the wave is reflected toward the transducer. The
transducer then serves as a receiver and “listens” for the
returning sound wave reconverting the mechanical to electrical
energy & subsequently to an image.
• The reflected waves gives the image of the tissue including the shape
• Because ultrasound waves are
transmitted and received at
reconstructed and refreshed,
providing a real-time image.
• The resolution of an ultrasound image refers to the ability to
discriminate two objects in close proximity to one another.
• Axial Resolution
The ability to identify as separate
two objects in the direction of
the traveling sound wave &
directly proportional with the
• Lateral Resolution
The ability to identify separately
objects that are equidistant from
the transducer & depends on the
ultrasound beam focus.
• As sound waves transit tissues, energy is lost or attenuated by
reflection, scattering, Interference, or absorption.
• Reflection is the key physical phenomenon that allows
information to return to the transducer as mechanical energy
• The amount of the reflected waves (Subsequently the image
resolution) depends mainly on the impendence of two adjacent
• Impendence is the property influenced by the density & stiffness of
The liver is used as a landmark for echogenicity. Darker structures are
hypoechoic (High water content), brighter structures are hyperechoic
(Less water content), Structures with similar echogenecity are Isoechoic,
& structures with no echogenecity (e.g. Simple Cysts) are anechoic.
• The interaction of ultrasound waves with tissues may produce
images that do not reflect the true underlying anatomy
“artifacts.” although which may be misleading, it also may assist the
diagnosis (e.g. acoustical shadows in stone diseases, or comet tail
appearance on reverberation of waves through gas containing
structures e.g. colon)
• Grey-Scale Ultrasound
• Doppler Ultrasound
• Spatial Compounding
• Harmonic Scanning
• Contrast media in US
• 3-Dimentional Scanning
• Grey-Scale Ultrasound
• Gray-scale B-mode ultrasonography is the most commonly
employed mode of ultrasound. This pulsed-wave technique
produces real-time two-dimensional images consisting of shades
• Evaluation of gray-scale imaging requires the ability to recognize
normal patterns of echogenicity from anatomic structures. Variations
from these expected patterns of echogenicity indicate disorders of
anatomy or physiology.
• Doppler Ultrasound
• The Doppler ultrasound mode depends on the physical principle
of frequency shift when sound waves strike a moving object.
• The basic principle of Doppler ultrasound is that sound waves of
a certain frequency will be shifted or changed on the basis of the
direction and velocity of the moving object, as well as the angle
• Color Doppler ultrasonography allows for evaluation of the
velocity and direction of motion. A color map may be applied to
direction with the most common assignation of the color blue to
motion away from the transducer and red for motion toward the
• Three Dimensional Scanning
has been used extensively
obstetrics and gynecology but so
far has limited application in
urology. 3-D scanning produces a
composite of images (data set),which
can then be manipulated to generate
additional views of the anatomy in
• Contrast media in US
Microbubbles (In special contrast media) are distributed in the vascular
system and create strong echoes with harmonics when struck by
sound waves. The bubbles themselves are rapidly degraded by their
interaction with the sound waves.
US with contrast media is useful in detection of areas with increased
• Renal Ultrasound
Assessment of renal and perirenal masses
Assessment of the dilated upper urinary tract
Assessment of flank pain during pregnancy
Evaluation of hematuria in patients who are not candidates for
5. Assessment of the effects of voiding on the upper urinary tract
6. Evaluation for and monitoring of urinary stones
7. Intraoperative renal parenchyma and vascular imaging for ablation
of renal masses
8. Percutaneous access to the renal collecting system
9. Guidance for transcutaneous renal biopsies, cyst aspiration, or
ablation of renal masses
10. Postoperative evaluation of patients after renal and ureteral surgery
11. Postoperative evaluation of renal transplant patients
• Renal Ultrasound
Hypoechoic renal cortex
Hyperechoic central hilum
Parenchymal thickness more than 7 mm
• Renal Ultrasound
• Ureter. US has limited usefulness in most ureteral disorders but for a
• Dilated ureters may be seen, ureteroceles demonstrated within the
bladder, and small calculi may be imaged, especially in the pelvic
• Color-flow demonstration of asymmetric jets of urine from the
ureteral orifices in the bladder often indicates the presence of uretral
• Pelvic Ultrasound
Measurement of bladder volume or postvoiding residual urine
Assessment of prostate size and morphology
Demonstration of secondary signs of bladder outlet obstruction
Evaluate bladder wall configuration and thickness
Evaluation of hematuria of lower urinary tract origin
The detection of ureteroceles
Assessment for ureteral obstruction
Detection of perivesical fluid collections
Evaluation of clot retention
Confirmation of catheter position
Removal of retained catheter
Guidance of suprapubic tube placement
To establish bladder volume before flow rate determination.
• Pelvic Ultrasound
Empty Bladder (Although Prostate volume can be determined with
Lack of PVRU determination in clot retention, obesity, ascites,
bladder diverticulae, or peri-vesical collection.
• Scrotal Ultrasound
Assessment of scrotal and testicular mass
Assessment of scrotal and testicular pain (Absence of testicular
blood flow indicates tortion)
Evaluation of scrotal trauma
Evaluation of infertility
Follow-up of scrotal surgery
Evaluation of the empty or abnormal scrotum
• Ultrasound of penis & Urethra
Evaluation of erectile dysfunction
Documentation of fibrosis of the corpora cavernosa
Localization of foreign body
Evaluation of urethral stricture
Evaluation of urethral diverticulum
Assessment of penile trauma or pain
• Trans-Rectal Ultrasound
• TRUS should not be used as a routine investigation
Palpable prostatic nodule on DRE
Elevated levels of PSA
To guide prostatic needle biopsy (in case of PSA ≥ 10)
• TRUS is the main investigation to evaluate the prostate relative to
carcinoma, although it may also be used to evaluate the benign prostate
with regard to size and to look for abnormalities in cases of ejaculatory
• However, No Ultrasonographic findings to differentiate benign from
malignant prostatic changes.
Radionuclide imaging is the procedure of choice to evaluate renal
perfusion, obstruction and function. It is sensitive to changes that
induce focal or global changes in kidney function.
Scintigraphy is a non-invasive diagnostic meathod, it does not damage
the kidney, has no toxicity, results in minimal absorbed radiation, and is
free from allergic reactions.
Technetium 99m-diethylene triamine pentaacetic acid (99m
Tc-DTPA) is primarily a glomerular filtration agent
• Technetium 99m-diethylene triamine pentaacetic acid (99m TcDTPA) is the most useful for evaluation of obstruction & function.
• Technetium 99m-dimercapt succinic acid (99m Tc-DMSA) localizes
to the renal cortex therefore it is most useful for identifying
cortical defects and ectopic or abhorrent kidneys.
• Technetium 99m-mercaptoacetyl triglycine ( 99m Tc-MAG3) is an
excellent agent for imaging due to its photon emission, 6-hour halflife, and ease of preparation. It is limited in measurement of GFR
due to being bound to plasma proteins, but is of choice in renal
shows renal uptake,
and abnormal vascular
lesions, which may
tumors, or active
The most sensitive
indicator of renal
The indicator phase of
A diuretic (usually furosemide 0.5 mg/kg) is administered when
maximum col -lecting system activity is visualized.
The T-1/2 is the time it takes for collecting system activity to decrease by
50% from that at the time of diuretic administration.
Assessment of renal function & split renal functions for taking the
decision of nephrectomy.
Evaluation of transplant failure including obstruction, extravasation,
stenosis of arterial anastomosis.
Questionable or intermittent obstruction. (esp. UPJ Obstruction)
Evaluate for small urine leaks not detected by contrast studies.
The only Contraindication for Radioneucleotide administration is
CT has become one of the most integral parts of urologic practice,
and the CT urogram (CTU) has replaced IVU as the imaging
modality of choice in modern urology
The basis for CT imaging is the attenuation of x-ray photons as
they pass through the patient.
Tomography is an imaging method that produces 3-D images of
internal structures by recording the passage of x-rays as they pass
through different body tissues.
• A collimated x-ray beam is generated on one side of the patient,
and the amount of transmitted radiation is measured by a detector
placed on the opposite side of the x-ray beam.
• These measurements are then repeated systematically, while a series
of exposures from different projections is made as the x-ray beam
rotates around the patient. The result is production of a 3-D
image of internal structures in the human body.
• Complex computer algorithms allow reconstruction of CT data into
many forms, including different planes, such as coronal and sagittal.
• An abdominal CT starts at the diaphragm and ends at the iliac
crest. The pelvic CT begins at the iliac crest and terminates at the
• Intravenous contrast may be required for better delineation of
soft tissue. Oral contrast is not commonly used in urology but may
be helpful in certain cases to differentiate bowel from lymph nodes,
scar, or tumor
• Attenuation values are expressed in Hounsfield units (HU). The
HU scale or attenuation value is based on a reference scale
where air is assigned a value of −1000 HU and dense bone is
assigned the value of +1000 HU. Water is assigned 0 HU.
Prinephric Collections (abscess, urinoma, and hematoma)
Trauma : detecting the effect of renal trauma (vascular injury,
extravasation from vascular system or urinary tract, urinoma
formation, and impaired renal viability)
• As time progresses, the CT is replacing the IVU as a main line of
investigations of Urolithiasis
• Almost all renal and ureteral stones can be detected on helical CT
• In the work-up of Urolithiasis the sensitivity of Non-Contrast CT is
96% - 100% and specificity 92% - 100%.
• Stones in the distal ureter can be difficult to differentiate between
calcifications, (Confirmed by presence of backpressure
• Cysts & Masses
• When the unenhanced CT images of a renal mass are compared
with the enhanced images obtained in the cor tical medullar y or
An increase in HU (measured in the area of the renal mass) by
15 to 20 HU confirms the presence of a solid enhancing mass,
which is usually renal cancer.
The presence of fat, which should enhance less than 10
diagnostic for angiomyolipoma.
A hyperdense cyst shows no change in density between the
postcontrast and delayed-phase images
• With MDCT it is possible to perform a comprehensive evaluation
of the patient with one single examination, & so being one of the
most important studies in diagnosing gross & microscopic hematuria.
• As the most important cause of hematuria is urothelial tumours.
C.T with Contrast –
Right Renal Cell
MRI is increasingly being applied to the genitourinary system due to
the excellent contrast resolution of soft tissue, without the need for
contrast in many situations.
MRI is used when patients cannot be given iodinated contrast (e.g.
impaired renal functions, or contrast allergy) and when tissue findings
in the urinary system cannot be resolved using CT or
The patient is placed on a gantry that passes through the bore of
When exposed to a magnet field of sufficient strength, the free
water protons in the patient orient themselves along the magnetic field’s
This is the head-to-toe axis, straight through the bore of the magnet.
A radiofrequency (RF) antenna or “coil” is placed over the body part to
be imaged. It is the coil that transmits the RF pulses through the
When the RF pulse stops, protons release their energy, which is
detected and processed to obtain the magnetic resonance image
according to the absorption & release of the magnetic energy by the soft
Evaluation of solid or cystic renal masses.
Staging of renal malignancy.
Evaluation of venous structures.
Determination of vena cava involvement by renal cell carcinoma.
Characterization of adrenal pathology.
Difficulty with breath holding.
Retained magnetic foreign bodies, cochlear implants.
neurovascular aneurysm clips.
Urolithiasis because stones do not have signal characteristics that
allow them to be detected.
There is No Safe Dose of Radiation
Limit axial imaging studies to the anatomic area of interest
Substitute imaging studies not requiring ionizing radiation when
Limiting the time of exposure
Maximizing the distance from the radiation source