• Plain films of the abdomen are used primarily
to assess calcifications and intestinal
perforation or obstruction.
• The plain radiograph is commonly used as a
preliminary radiograph before other studies
such as CT and barium enema.
X ray abdomen
• The most common plain radiograph of the
abdomen is an anteroposterior (AP) view with
the patient in the supine position.
• The AP view of the abdomen is also called a
KUB film because it includes the kidneys,
ureters, and bladder.
• When acute abdominal disease is suspected
clinically, an erect film of the abdomen and a
posteroanterior (PA) view of the chest are also
• Soft Tissue
• The abdomen is composed primarily of soft
• The liver is a homogeneous structure located
in the right upper quadrant.
• In the left upper quadrant a similar angular
structure, the splenic angle, can be identified
by the fat shadow around the spleen.
A Normal plain film of the abdomen. The lower margins of the posterior
portion of the liver, the hepatic angle (H), and the lower part of the spleen (S)
are delineated by a fat shadow. Both kidneys (K) and the psoas muscle
shadows (arrowheads) are outlined by a fat shadow. The properitoneal fat
stripe is also shown bilaterally (arrows).
• Organ enlargement can be recognized by the
effect of displacement on nearby bowel loops
or by obliteration of the adjacent normal fat
or gas pattern.
• It is poorly differentiated in X rays.
• Fat Shadow
• Fat is present in the retroperitoneal space
adjacent to the psoas muscle.
• Gas Pattern
• It is seen in the stomach and colon, but it is
rarely seen in the normal small bowel because
the air rapidly traverses the organ.
• The presence of more than a minimal amount
of gas in the small bowel should be considered
abnormal and is indicative of a functional ileus
or mechanical obstruction.
• Identification of the differences between the gas
shadows of the jejunum, ileum, or colon helps to
assess the location of bowel obstruction.
• A gas pattern in distended intestinal loops is usually
limited above the point of mechanical obstruction,
but functional ileus has a more diffuse distribution in
both the small intestine and the colon.
• If the gas shadow in the intestine is displaced to an
unusual location, a soft-tissue mass, either
inflammatory or neoplastic, may be suspected.
• The presence of air-fluid levels in a distended
small intestine on upright films suggests either
functional ileus or mechanical obstruction.
• The presence of solid material with a mottled
appearance and small bubbles of gas
surrounded by the colonic contour suggests
feces in the colon.
• A large amount of gas seen in the peritoneal
cavity indicates postoperative status or bowel
• In the right upper quadrant, air that is seen in
the biliary tree or around the gallbladder
suggests cholecystoenteric fistula or
• Bony Structure or Calcification
• Bony structures comprise the ribs superiorly, the lumbar
spine, and the pelvis.
• Calcifications in the abdomen include calculi in the urinary
or biliary tract, pancreatic calcifications (which are usually
indicative of chronic pancreatitis, with or without
carcinoma), or ectopic gallstone in the small bowel
associated with mechanical obstruction from gallstone
• Suspicion of urinary calculi is a common indication for
• Ultrasonography is the better choice for evaluating
• The routine abdominal films are used to
assess pneumoperitoneum and air-fluid levels.
• The PA view of the chest is usually obtained as
part of an acute abdominal series because an
abnormality in the chest may have symptoms
referred to the abdomen.
• Plain abdominal radiography is less sensitive
in evaluating solid organs or metastases.
• Ultrasonography and CT, has shown to be
more sensitive in assessing disorders of the
abdominal solid organs and metastatic
• Acute cholecystitis is better assessed by
ultrasonography or nuclear medicine studies.
• Radiographs of the abdomen when used to
evaluate the urinary tract are often referred
to as KUBs (kidney, ureter, and bladder).
• KUBs may serve a role as preliminary films
prior to an examination such as an
intravenous urography, or they may be used
as a general evaluation of the abdomen or the
Normal KUB. Note that portions of the normal renal
contours (arrows) are visible and should be evaluated.
No abnormal calcifications, soft tissue densities, or
bony lesions are evident.
• In the setting of trauma, fractures of the
lumbar transverse processes suggest possible
renal injuries and pelvic fractures raise
concern for coexistent bladder or urethral
• Air and calcifications should be specifically
sought over the urinary tract.
• Radiographs are also useful for detecting and
evaluating urinary tract calculi.
• Emphysematous pyelonephritis, a urologic
emergency with high mortality, is the result of a
renal infection by gas-producing organisms and may
be diagnosed on plain films by mottled or linear
collections of air within the renal parenchyma.
• If emphysematous pyelonephritis is suspected,
emergency computed tomography (CT) should be
performed to delineate the extent of involvement
and immediate urologic consultation obtained.
• Intravenous urography (IVU), also known as
intravenous pyelography (or more commonly, the
• The study should always begin with a scout KUB.
• This has several purposes including detection of
calcifications (which may be obscured after
contrast material is injected), exclusion of
contraindications to the study (retained barium,
• Intravenously injected iodinated contrast is
excreted primarily by glomerular filtration in
the kidney, opacifying the urinary tract as it
progresses from the kidney through the ureter
and to the bladder.
• Capturing this sequential "opacification" on
radiographs is the fundamental basis of the
• Optimal visualization of the kidney is accomplished
very early in the examination.
• Within 1 to 3 minutes after injection, the contrast
bolus is filtered by the glomeruli and fills the nephron,
resulting in intense opacification of the renal
parenchyma; this phase of contrast opacification is
called the nephrogram.
• Evaluation of the kidneys during the nephrographic
phase is often enhanced with tomograms
• The kidneys should be evaluated for their position,
orientation, size, contour, and radiographic density.
Normal nephrotomogram. Note the position of the kidneys
within the abdomen, with the right kidney slightly lower than
the left; the size of the kidneys, the symmetry of the
nephrograms; and the renal contour, which is smooth.
• Soon after the nephrographic phase, contrast
begins filling the intrarenal collecting system
including the calyces and renal pelvis. This
portion of the study is termed the pyelographic
• Several films are used to evaluate the collecting
system (intrarenal collecting system and ureter)
• The intrarenal collecting system consists of
calyces, infundibula, and the renal pelvis.
• The individual renal calyx is a delicate appearing
• The normal delicate, cup-like appearance can be
distorted or irregular in conditions such as
papillary necrosis, tuberculosis, or transitional
• Subtle rounding or ballooning of the calyces is
one of the earliest signs of urinary tract
• The renal pelvis should be evaluated for filling
defects and mass effect.
Normal pyelogram. Note the delicate cup-
shaped appearance of the calyces and the
relative symmetry of the renal pelvis with no
evidence of dilation or mass effect.
• The ureter extends from the ureteral pelvic
junction to the ureteral vesicle junction.
• The ureter is an actively peristalsing structure
that is not normally seen in total on the IVU.
• In fact, complete visualization of the ureter
may suggest distal obstruction.
• The ureter should be inspected for filling
defects, which can be caused by stones or
tumor, and should be symmetric in size.
Normal KUB showing contrast opacified ureters. Due to peristalsis, the ureter
may not be visible in its entirety.
• Finally, the bladder is opacified last on the study
beginning around 5 minutes after injection.
• Early filling films, later distended films, and
postvoiding images complete the evaluation of
• Bladder wall thickness can sometimes be
visualized and assessed, especially if thickened.
• Additionally, the bladder mucosa should be
scrutinized for irregularity or filling defects that
may suggest a mass.
Normal bladder. Note the location of the
bladder just above the pubic symphysis, as well
as its smooth contour. No filling defects should
• Direct injection of water-soluble iodinated contrast
material is a useful method of examining various regions of
the urinary tract.
• The advantage of this method of evaluation is the direct
control over the contrast injection rather than reliance on
secondary excretion from the kidney.
• Retrograde pyelography, often carried out in conjunction
with cystoscopy, is performed by placing a small catheter
into the distal ureter.
• Contrast material is then injected through this catheter into
one or both ureters.
• Fluoroscopy and conventional radiographs should then be
• This study usually results in excellent
evaluation of the ureter and intrarenal
• The ureter is typically seen in its entirety,
which rarely occurs with other imaging
• Interpretation is similar to that of the IVU.
• Imaging of the bladder is performed with a
cystogram, for which a catheter is placed into the
bladder and contrast material is then injected.
• One advantage to cystography is that
vesicoureteral reflux can be evaluated during the
conventional cystogram unlike during IVU.
• CT cystography, in which after contrast
instillation CT imaging is utilized instead of
conventional films, has been used in the setting
of trauma to evaluate for bladder injury.
• The urethra may be evaluated with contrast material
via two methods.
• In one, the urethra is evaluated during voiding, often
following a cystogram (voiding cystourethrogram or
• Alternatively, a retrograde study may be performed
• The urethra in males is generally evaluated for injuries
but may also be examined for filling defects, masses,
strictures, and fistula.
• The female urethra is most commonly examined for
Normal antegrade urethrogram . The mild areas of narrowing and dilation are
normal. On an antegrade study, unlike a retrograde examination, the
proximal urethral is distended and readily assessed. No evidence of stricture
or extravasation is seen.
Normal female VCUG. Note the smooth
contour of the urinary bladder and the
short, conical appearing urethra.
• kidneys should be assessed for
echogenecity,size, location, and symmetry.
• Unlike the IVU, where masses are often
nonspecific, ultrasonography allows a more
detailed evaluation including the ability to
confidently diagnose the most common renal
mass—the simple cyst.
• Calcifications are characteristic on ultrasound.
• Renal stones or calcifications may be detected
within the renal parenchyma or in the
intrarenal collecting system.
• Ultrasonography is also excellent for detecting
hydronephrosis with the distended collecting
system being easily recognized.
• The ureters are not normally seen on
ultrasound due to obscuring overlying tissue
and their small size.
• The bladder may demonstrate mass lesions,
such as transitional cell carcinoma, or stones.
• The urethra is not typically seen on an
ultrasound image although urethral
diverticula may occasionally be demonstrated.
• CT is now the dominant radiologic imaging
modality for evaluation of the urinary tract.
• CT scans of the urinary tract may be
performed with and/or without intravenous
iodinated contrast material depending on the
• Noncontrast studies may be performed to
evaluate stone disease and other
• Additionally, noncontrast views of the kidneys
serve as a baseline to evaluate for lesion
enhancement after contrast administration, a
critical factor in mass evaluation.
• With rapid scanning and contrast bolus timing,
several sequential phases of opacification within
the kidney can be delineated by CT including
corticomedullary, nephrographic, and excretory
• The corticomedullary phase can be seen if
scanning is performed during the first 20 to 90
seconds after contrast administration and
represents the early preferential blood flow to
the renal cortex
• Subsequently, contrast begins to pass into the distal collecting
tubules within the renal medulla, resulting in a more
homogeneous opacification of the renal parenchyma, termed
the CT nephrographic phase. This generally occurs around 2
to 4 minutes after contrast medium injection.
• Finally, the excretory phase is seen when contrast opacifies
the collecting system .
• Each different phase of opacification may better demonstrate
different disease processes.
• CT has the ability to noninvasively evaluate the
vascular system, and thin-section early CT images
accurately demonstrate the main arterial and
venous structures of the kidney .
• Just as with IVU or any modality, the kidneys
should be evaluated for position, orientation,
size, and radiographic density.
• Unlike IVU, however, CT provides much greater
specificity regarding renal disease, including mass
• CT is sensitive in detecting renal masses.
Normal CT angiogram of the renal arteries, 3-D
reconstruction. Note that this image clearly
demonstrates that there are two right renal arteries.
This is a normal variant. In this case, the renal arteries
are patent without evidence of significant stenosis.
• CT is also useful in staging renal neoplasms.
• Non-neoplastic renal disease, such as trauma and
complicated infections, is accurately demonstrated on
• Spiral CT has become the study of choice for evaluating
suspected ureteral stones.
• The bladder wall should be evaluated for thickening
and irregularity, which may suggest hypertrophy,
inflammation, or carcinoma.
• Stones may be detected within the bladder.
• The urethra is not normally seen on CT.
Magnetic Resonance Imaging
• Just like CT, technical advances in magnetic
resonance (MR) imaging have led to
increasing use in urinary imaging.
• MR imaging of the kidney is performed with
gadolinium as the contrast agent, not
iodinated contrast material.
• Like CT, contrast-enhanced phases of imaging
(arterial, corticomedullary, nephrographic,
and excretory) are all visible.
Normal MRI of the kidneys. The appearance of the kidneys is
variable on MR imaging depending on imaging factors. The top
left image is a T1-weighted sequence and the top right is T2
weighted. The bottom images were obtained after gadolinium
injection and demonstrate the corticomedullary and
Normal MR imaging of the kidneys.
This image was obtained in the
coronal plane and after gadolinium
• Renal evaluation is typically performed by
intravenous bolus injection of renal-specific
agents such as technetium-labeled
• Images are acquired every few seconds that
demonstrate renal blood flow, with additional
images obtained over several minutes that
show renal uptake and excretion.
• Information about renal perfusion, morphology, relative function of
each kidney, and excretion can be extremely useful in evaluation of
conditions such as renovascular hypertension, obstruction, and
renal transplant examination.
• In general, nuclear medicine renal studies suffer from fairly low
spatial resolution and, therefore, are often used in conjunction with
other imaging studies.
• Radionuclide cystography is another useful test used to diagnose
and monitor vesicoureteral reflux.
• Radioactive iodine labeled metaiodobenzylguanidine (MIBG)
examination. MIBG collects in adrenal medullary tissue and is useful
in diagnosis and evaluation of pheochromocytoma.
• The renal arteriogram is performed after
puncture of a more peripheral vessel such as the
common femoral artery, with advancement of a
catheter into the renal artery origin.
• Contrast material is injected via the catheter and
rapid, typically digital, conventional radiographic
images are obtained.
• The main role for angiography today is aiding and
guiding interventional techniques.
Normal renal arteriogram. The renal arterial system is
visualized in detail with spatial resolution superior to
that of other techniques. Delayed images can be
obtained to show the venous phase and/or the
collecting system filling with contrast material.
Plain X ray
• Limited use for evaluating Genito urinary
• Can be used in finding abnormal stones,
bones, gases and masses.
• Utility is limited by its lack of sensitivity and
• Can be used effectively to follow
radiographically visible stone disease.
• Also used for assessing stone burden or
urethral stone passage.
• Assesses both morphology and function .
• Lack of sensitivity and specificity.
• Used to evaluate for mucosal lesions—
transitional cell carcinoma of upper urinary
tracts, urinary tract for congenital anomalies
and to assess obstruction.
• Replaced by modern modalities in many
indications such as renal masses, Urinary tract
infections, trauma, ureteric colic and vascular
diseases eg.renovasular hypertension.
• Voiding cysto urethrography is used in
evaluating urethral reflux.
• Retrograde Urography is used for suspected
• Renal scintigraphy is used for the assessment
of Renal function i.e obstruction, renovascular
hypertension, Renal transplants.
• MIBG is used to diagnose
• MIBG is also used for detecting metastatic or
recurrent disease or extra-adrenal lesions.