TECHNIQUES AND NORMAL
• Luminal Contrast Examinations
• Barium sulfate suspensions are the preferred
material for most examinations.
• Water-soluble contrast agents, which contain
organically bound iodine, are primarily to
demonstrate perforation of a hollow viscus.
UPPER GASTROINTESTINAL TRACT
• pharynx, esophagus, stomach, and duodenum.
Filming of the pharynx is usually done with the
patient in the frontal and lateral positions.
In the frontal view, the paired valleculae and
piriform sinuses are separated.
The lateral view of the pharynx ---base of the
tongue, hyoid bone, and epiglottis anteriorly, and
the posterior pharyngeal wall and cervical spine
• The esophagus, stomach, and duodenum are
usually examined together as part of the upper
Observation of esophageal motility
single-contrast upper gastrointestinal series
double-contrast upper gastrointestinal series
--involves the use of a high-density barium
suspension plus gas-producing crystals
Prone frontal radiograph of stomach and duodenum
from a single-contrast upper gastrointestinal
examination. The duodenal bulb (D) is attached to the
gastric antrum by the pyloric channel.
Supine frontal film of the stomach and duodenum from
a double-contrast upper gastrointestinal examination in
which a high-density barium suspension and gas
crystals (CO2) are used.
• Barium studies of the upper gastrointestinal
tract evaluate gastric function poorly.
• Radionuclide gastric emptying studies are
more effective for this purpose.
• The duodenum assumes a C-shape
configuration within the upper abdomen.
• consists of the jejunum and ileum.
• The following three methods can be used to
examine the small intestine:
(1) peroral small bowel series,
(2) enteroclysis, and
(3) various retrograde techniques.
(1) peroral small bowel series,
• most commonly used and is often done
immediately following an upper gastrointestinal
• The patient ingests 16 to 24 ounces of barium
suspension and serial films of the abdomen are
obtained in a timely order.
• In addition, smaller films with pressure on the
abdomen (i.e., compression) are used to separate
and visualize all of the loops of the small bowel;
the entire small bowel, including the terminal
ileum, is filmed in this fashion.
Large film of the abdomen from a peroral
small-bowel examination with the entire
small intestine opacified with barium
Compression film of the small bowel from a
peroral examination with separation and clear
visualization of the small bowel loops.
• Enteroclysis is an intubated examination of the
• The small intestine is intubated by a nasal or oral
route with a small-bore enteric tube, which is
directed with fluoroscopic guidance into the
distal duodenum or proximal jejunum.
• Single contrast technique.
• Double contrast technique.
• Compared to the peroral small-bowel
examination, the enteroclysis techniques permits
more exact visualization of small-bowel loops.
Large film of the abdomen from an enteroclysis examination of
the small intestine. The small bowel is intubated with the tip of
the tube (arrow) in the jejunum. Compared to the peroral
examination, the small-bowel loops are distended more fully,
causing the mucosal folds to assume a transverse orientation.
Compression film of the small-bowel loops in the pelvis
with the patient in a prone position. Although the loops
are overlapped, the "see-through" effect using a dilute
barium suspension permits their clear visualization.
• As with the upper gastrointestinal
examinations, the colon can be evaluated by
the following techniques:
(1) single-contrast barium enema or
(2) double-contrast barium enema.
• Both examinations require insertion of a rectal
tip for installation of the examining materials.
• The large intestine consists of the rectum,
sigmoid colon, descending colon, splenic
flexure, transverse colon, hepatic flexure,
ascending colon, and cecum.
• The mucosal surface has a smooth
appearance and the colonic contour is
indented by the haustra, which are less
numerous in the descending portion of the
Double-contrast view of the right side of the colon
showing the cecum (C), ileocecal junction (J), refluxed
terminal ileum (I), and the appendix (arrow). The
multiple haustrations of the colon are seen well and
are produced by the teniae coli
• Upper gastrointestinal endoscopy visualizes the
mucosal surfaces of the esophagus, stomach, and
• Endoscopy does not assess functional
abnormalities of these organs.
• The major advantage of endoscopy compared to
barium examination of the upper gastrointestinal
tract is a better demonstration of milder
inflammatory processes, such as small peptic
ulcers and erosions.
• Endoscopy of the mesenteric portions of the
small intestine is called Enteroscopy .
• diffuse small-bowel disease, especially if
biopsy is needed
• those with unexplained gastrointestinal
• Colonoscopy is both a diagnostic and therapeutic
Inflammatory and neoplastic diseases of the
Biopsies can be obtained when needed.
colonic polyps can be removed through the
• A major role of CT scanning, especially in the
esophagus and colon, is staging malignancy of
• Recurrent masses appearing after surgery may
also be biopsied percutaneously.
• An ultrasound can be used to assess for
inflammatory disorders, such as acute
MAGNETIC RESONANCE IMAGING
• MR imaging of the GIT is being used
to evaluate and stage malignancies, especially
of the esophagus and rectum
to assess inflammatory and obstructive bowel
• Upper gastrointestinal tract and small bowel
• require minimal preparation when compared to
• For an upper gastrointestinal or small-bowel
examination, the patient should have nothing
orally after midnight or the next morning
preceding the radiographic study.
• Fluid and food in the stomach and small intestine
degrade the examination by interfering with
good mucosal visualization and causing artifacts
that may mimic disease.
• oral fluids, and several cathartics the day preceding the barium
• The standard preparation includes
• (1) a 24-hour clear liquid diet,
• (2) oral hydration,
• (3) a saline cathartic (e.g., magnesium citrate) in the afternoon,
• (4) an irritant cathartic (e.g., castor oil) in the early evening, and
• (5) a tap-water cleansing enema the morning of the radiographic
examination 30 to 60 minutes before the barium enema is
• Magnesium containing cathartics is avoided in patients with renal
Specific Contrast Examinations
• Selection of an appropriate technique will depend on
the clinical indications for the examination, the efficacy
of the various techniques, and the age and physical
condition of the patient being examined.
• UPPER GASTROINTESTINAL TRACT
• dysphagia, odynophagia, suspicion of esophageal
varices, dyspepsia, upper gastrointestinal bleeding,
and evaluation of obstruction.
• The diseases that are detected most effectively include
malignancies, peptic stricture, esophageal mucosal
ring, moderate to severe reflux.
• Indications –
gastrointestinal bleeding that is not localized to
the other organs of the gastrointestinal tract
diarrhea or more specifically steatorrhea
inflammatory bowel disease
• small-bowel bleeding causes: Meckel's
diverticulum, Crohn's disease, ischemic enteritis,
and primary and secondary neoplasms.
• Small-bowel obstruction is usually due to
adhesions, external hernias, or intrinsic or
• The enteroclysis examination is often preferred
for evaluating small-bowel obstruction or
potential focal lesions of the small intestine, such
as Meckel's diverticulum.
suspicion of inflammatory bowel disease,
question of neoplastic disease, and
evaluation of colonic obstruction.
• Common causes of Colonic bleeding are diverticulosis,
idiopathic colitis, larger colonic polyps and carcinoma, and
• Common causes of colonic obstruction include
diverticulitis, colonic malignancy, volvulus of the large
bowel, and extrinsic disorders, especially pelvic malignancy
invading the rectosigmoid region of the colon.
• The diseases that are detected most effectively include
diverticular disease and its complications, more severe
forms of idiopathic and ischemic colitis, larger colonic
polyps (i.e., greater than 1 cm in size), and colonic
• The diagnosis of diseases of the liver, biliary tract, and
pancreas optimally depends on using both clinical and
• Contrast studies such as endoscopic retrograde
cholangiopancreatography (ERCP) and percutaneous
transhepatic cholangiography (PTC) are often helpful in
analyzing diseases of the liver, biliary tree, and pancreas.
• Digital cross-sectional imaging, nuclear medicine (NM) and
an important form of NM called positron emission
tomography (PET), and angiography .
• Cross-sectional techniques consist of ultrasound (US),
computed tomography (CT), and magnetic resonance (MR)
• With USG, normal organs are displayed as structures of
• Vascular flow can be visualized by US with Doppler imaging,
which consists of three types:
• color, spectral, or power Doppler imaging.
• In color Doppler imaging, Color shade and color intensity
reflect blood flow direction and velocity, respectively.
• Spectral Doppler imaging is portrayed as a sine-wave form
in which peaks represent increasing velocity and valleys
represent decreasing velocity of flow.
• This is often combined with color Doppler imaging and
together is called duplex imaging.
• Nuclear medicine techniques utilize the
administration of radioactively labeled
substances chemically bonded to physiologic
• A more recent application of NM is PET, in which
positrons emitted, often from radioactive sugar-
containing compounds, are detected and imaged.
• The term for different shades within a nuclear
medicine image is activity.
• The term for different shades within a CT
image is attenuation or density.
CT showing normal liver (L), pancreas
(arrowheads), and biliary tree, in both
the liver and pancreas (arrows).
• The term for different shades within an
angiographic image is density.
Magnetic Resonance Imaging
• MR imaging has superb contrast resolution.
• Generalized parenchymal lesion detection and
characterization, together with MR angiography,
or MRA, have been improved greatly with the use
of MR imaging-specific intravenous contrast
agents, especially gadolinium, Gd.
• The term for different shades within an MR
image is signal intensity.
• Flow is identified by signal intensity changes in
the blood vessels.
Dynamic gadolinium-enhanced T1-weighted gradient
echo image of the upper abdomen, taken at the level of
the midliver, demonstrating homogeneous liver, with
interspersed intrahepatic vessels, and spleen.
Dynamic gadolinium-enhanced T1-weighted gradient echo image
of the upper abdomen, taken at the level of the pancreas and
kidneys, demonstrating the homogeneous pancreatic body and
tail with pancreatic duct (arrow), and the corticomedullary
differentiation in the kidneys.
• Diseases of the liver, biliary system, and
pancreas can be conveniently divided into the
following categories to help illustrate the
optimal sequences of imaging techniques:
diffuse hepatocellular disease, focal hepatic
diseases, abdominal trauma, inflammatory
disease of the biliary tract, and pancreatic
inflammation or neoplasm.
Diffuse Hepatocellular Disease
• CT is the first study used to survey the liver
because it is moderately sensitive to liver
lesions and is also helpful for evaluating
• MR imaging may be the most sensitive
modality for detecting and characterizing
diffuse diseases of the liver, including cirrhosis
and hemochromatosis, especially when
combined with contrast agents.
Focal Hepatic Diseases
• USG is often used first, because it is inexpensive,
widely available, and moderately sensitive to localized
lesions in the absence of preexisting diffuse diseases,
such as cirrhosis.
• CT is a pivotal examination, often employed after US. It
is used as a survey of the entire body, is easy to
compare in serial studies, and is sensitive to disease.
• Contrast-enhanced MDCT scanners can be used to
perform CT angiography, or CTA, which is a
noninvasive means of producing images depicting
vessels much like conventional angiography.
• NM techniques can be used to analyze a focal lesion
within the liver for possible cavernous hemangioma.
• MR imaging is used frequently to characterize focal
lesions within the liver, especially those discovered
during survey techniques like US or CT.
• NM and MR imaging are considered the optimal means
for evaluating the liver for cavernous hemangioma,
and both are highly accurate (approximately 95%) in
evaluating the liver for cavernous hemangioma.
• CT is the only commonly accepted means for analyzing
abdominal trauma, particularly of the liver.
• CT is reasonably accurate in the detection of trauma-
related abnormalities of the liver, biliary system, and
• US may be useful if CT is not available or to quickly
identify intraperitoneal hemorrhage in patients who
are in the emergency department and are going
directly to the operating room.
• Angiography may be useful to embolize persistently
bleeding arteries in the liver or spleen when surgery is
Pancreatic Inflammation or Neoplasm
• Ultrasound is often the initial means to study
pancreatic inflammation or neoplasm.
• If a lesion has already been detected by US
and additional confirmation is required, CT is
the method of choice.
• Recent advances in MR imaging, especially
MRCP, aids in pancreatic and biliary duct