ABDOMEN

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ABDOMEN PELVIS PATHOLOGY SCANNING PROTOCOLS
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PATHOLOGIES
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ABDOMINAL MESENTERIC CYST
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ABDOMINAL CYST
An abdominal CT scan revealed a large right upper
quadrant cyst measuring 14x17x21 cm ( lateral,
anteroposterior and craniocaudal)There was mass
effect upon the liver and duodenum. The cyst had
a thin smooth wall with internal fluid and high
density material consistent with a blood clot.
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RENAL CYST
NO CONTRAST
CONTRAST
They appear as well-defined, thin-walled, round
or oval masses, with attenuation close or equal
to that of water (0-20 HU).
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POLYCYSTIC KIDNEY DISEASE
In polycystic kidney disease many fluid-filled
cysts develop in the kidneys. Gradually these
cysts replace the normal kidney tissue enlarging
the kidneys but making them less and less able to
function normally. Eventually the kidneys fail
completely
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HEPATOMEGALY
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STEATOSIS
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Hepatocellular carcinoma The most common
primary malignant neoplasm of the liver. HCC
typically appears hypodense on non-contrast scans
and hyperdense or hypervascular on arterial phase
imaging
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ASCITES
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SPLENOMEGALY
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SPLENIC INFARCTION
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APPENDICITS
An axial slice of a CT scan done with the use of
intravenous and oral contrast is presented. The
arrow points to an area of soft tissue induration
within the retrocecal fat. There is a rim like
area of higher attenuation within this area. The
structure is fluid filled. These features are
compatible with a diagnosis of acute appendicitis
and the presence of rupture cannot be excluded.
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DIVERTICULITS
Diverticulitis is inflammation or infection of
small pouches, called diverticula, that develop
along the walls of your intestines. The formation
of the pouches themselves is a relatively benign
condition known as diverticulosis. The pouches
can develop anywhere on the digestive tract, but
they most commonly form at the end of the
descending and sigmoid colons, and they also
frequently occur on the first section of the
small intestine (although they rarely cause
problems there).
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DIVERTICULITS
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ABDOMINAL ABSCESS
Psoas abscess (blue arrow), and abscess
dissecting anteriorly in transversalis fascia.
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BOWEL OBSTRUCTION
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LIVER METS
Lung cancer, small cell. Contrast-enhanced CT
scan of the abdomen. Axial section through the
liver shows multiple hypoattenuating areas in the
liver. Poorly defined margins, attenuation
greater than that of water, and scattered
distribution in a patient with known lung cancer
is most consistent with metastatic disease.
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ESOPHAGEAL CANCER
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WILMS TUMOR
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WILMS TUMOR
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ADRENAL METS
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RENAL STONE
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HYDRONEPHROSIS
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BLADDER CANCER
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KIDNEY CANCER
Kidney cancer affects some 30,000 people in the
United States each year, and close to 12,000 die
from the disease. It is the eighth most common
cancer in men and the tenth most common in women.
Smoking is the major risk factor,
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HORSESHOE KIDNEYS
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PHEOCHROMOCYTOMA
Pheochromocytoma is a tumor of the adrenal gland
that causes excess release of epinephrine and
norepinephrine, hormones that regulate heart rate
and blood pressure
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CIRRHOSIS
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HEMANGIOMA
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A cavernous hepatic hemangioma is the most common
non-cancerous tumor of the liver. It is believed
to be a congenital defect, and is usually not
discovered until medical pictures are taken of
the liver for some other reason.
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CHOLELITHIASIS
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CHOLECYSTITIS
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PANCREATIC CANCER
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PANCREATITIS
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ABDOMINAL ANEURYSM
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PROTOCOLS
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• Exam Preparation
• When possible, patients fast for 2 to 6 hours
  before the examination. Fasting results in an
  empty proximal GI tract, facilitating its
  evaluation and also limiting the potential hazard
  of aspiration of stomach contents in the event of
  GI upset due to IV administration of a contrast
  agent.
• 2. In most cases, an oral contrast agent is
  administered to distend the GI tract and clearly
  demonstrate the intestinal lumen. The agent used
  may be a dilute solution of an iodinated contrast
  medium, barium sulfate, or water. For general
  studies of the abdomen and pelvis, 750 to 1500 mL
  of oral contrast agent is administered 30 to 120
  minutes before the exam.
• 3. Example protocol for oral contrast agent
  administration is
• a. 450 mL given 90 to 120 minutes before the exam
  for opacification of the distal intestines.
• b. 300 to 450 mL given 30 minutes before the exam
  for opacification of the proximal
• intestines.
• c. An additional volume of 150 to 250 mL given
  just before scanning for opacification of the
  stomach and duodenum.

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Administration of Intravenous Contrast Agents 1.
When not contraindicated, the administration of
an iodinated IV contrast agent improves the
quality of abdominal and pelvic CT imaging
by a.Enhancing, or increasing the CT density of,
abdominal organ parenchyma. b.Increasing the
detectability of lesions from normal
structures. c.Opacifying vascular
structures. d.Providing assessment of organ
perfusion and function. 2. There are also
clinical indications for non-contrast or pre- and
post-contrast imaging, including a.Characterizing
the enhancement pattern of a lesion. b.Evaluation
of calcifications within organ
parenchyma. c.Assessment of unenhanced
parenchymal attenuation values. d.Identification
of calculi within the bile ducts, gallbladder,
urinary tract, and appendix
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Contrast agent dose ranges from approximately 50
to 150 mL. The total dose depends on the
patient's condition and the clinical indication
for the study. Injection rates vary between 2.0
and 5.0 mL/sec. The rate selected depends on the
enhancement phase(s) to be acquired and the
capacity of the venous access. The delay
between the initiation of contrast agent
administration and scanning is tailored to the
required phase of enhancement and coordinated
with the injection rate.
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FEET FIRST OR HEAD FIRST
SPONGE
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ABDOMEN STANDARD
SCOUT AP LANDMARK XIPHOID TIP SCAN MODE
Spiral I.V. CONTRAST 1.5-2 ml/sec, 100-150
ML SCAN DELAY 75-80 sec ORAL CONTRAST 400 ml
45 MINUTES BEFORE SCAN, 200 ML JUST BEFORE SCAN
BREATH HOLD SUSPENDED EXPIRATION SLICE
THICKNESS 8-10 MM START LOCATION LUNG
BASES END LOCATION ILIAC CREST FILMING
STANDARD, LUNGS, LIVER BONE FOR TRAUMA CANCER
ROUTINE
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ABDOMEN-KIDNEY STONE
SCOUT AP LANDMARK XIPHOID TIP SCAN MODE
Spiral NO ORAL CONTRAST NO IV CONTRAST BREATH
HOLD SUSPENDED EXPIRATION SLICE THICKNESS
5MM START LOCATION ABOVE KIDNEYS END
LOCATION S. PUBIS FILMING STANDARD
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ABDOMEN LIVER MASS-3 PHASE
SCOUT AP LANDMARK XIPHOID TIP SCAN MODE
SPIRAL I.V. CONTRAST 4-5 ml/sec, 100-150
ML SCAN DELAY 1. NON-CONTRAST, 2. ARTERIAL 30
SEC. 3. PORTAL 70 SEC. ORAL CONTRAST 400 ml
45 MINUTES BEFORE SCAN, 200 ML JUST BEFORE SCAN
BREATH HOLD SUSPENDED EXPIRATION SLICE
THICKNESS 4-5 MM START LOCATION LUNG
BASES END LOCATION ILIAC CREST FILMING
STANDARD LIVER
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Arterial phase The period of peak arterial
enhancement typically occurs at 25 to 35 seconds
after the initiation of contrast agent
administration. During this phase, hypervascular
tumors, or tumors supplied by the hepatic artery,
undergo maximal enhancement. The lesions are made
conspicuous by the relatively unenhanced hepatic
parenchyma surrounding them. Portal (or
hepatic) venous phase The period of peak hepatic
parenchymal enhancement during which contrast
material redistributes from the blood into the
extravascular spaces. Typically occurring at 60
to 70 seconds after the initiation of contrast
agent administration, this is the phase during
which hypovascular lesions are most conspicuous
owing to their density difference from the
enhancing hepatic parenchyma. Equilibrium
phase Usually occurs at 2 to 3 minutes after the
initiation of contrast agent administration.
During this phase, hepatic parenchymal
enhancement dissipates, and there is minimal
difference in contrast enhancement between the
intravascular and extravascular spaces. Many
hepatic lesions become indistinguishable from
their surroundings. The rapid acquisition made
possible by MDCT helps avoid scanning during this
phase.
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NON-CONTRAST
ARTERIAL
PORTAL
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The delayed phase of hepatic data acquisition
occurs approximately 5 to 20 minutes after
contrast agent administration. This phase is used
primarily to demonstrate the complete fill-in
of a hemangioma as it becomes isodense with
surrounding parenchyma.
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The CT density of the unenhanced spleen is
between 40 and 60 HU, which is approximately 10
HU less than that of the unenhanced liver. The
spleen is optimally imaged after administration
of a contrast agent. On arterial phase imaging,
the spleen demonstrates a heterogeneous
enhancement pattern. The preferred timing for CT
acquisition of the spleen is the portal venous
phase (60-70 seconds), when a more homogeneous
pattern of enhancement is demonstrated.
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Most pancreatic tumors appear hypodense in
comparison with surrounding contrast-enhanced
pancreatic parenchyma. Imaging the pancreas
during the phase of peak parenchymal enhancement
vastly increases the conspicuity of most
pancreatic neoplasms. The pancreatic phase of
contrast enhancement is a delayed arterial phase
occurring approximately 35 to 45 seconds after
the start of contrast agent administration,
assuming that an adequate volume is injected at a
rate of 3 mL/sec or higher.
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ABDOMEN- PANCREAS
SCOUT AP LANDMARK XIPHOID TIP SCANNING MODE
SPIRAL I.V. CONTRAST 3 - 5 ml/sec SCAN DELAY
Arterial 25 sec, delayed arterial 35 -45 sec,
venous 60-70 sec ORAL
CONTRAST 400 ml 45 MINUTES BEFORE SCAN, 200 ml
15 MINUTES BEFORE SCAN BREATH HOLD SUSPENDED
EXPIRATION SLICE THICKNESS 3-5 MM THROUGH
PANCREAS START LOCATION LUNG BASES END
LOCATION ILIAC CREST FILMING STANDARD LIVER
BONE FOR TRAUMA CANCER
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The primary goal of multiphasic CT evaluation of
a pancreatic mass is the determination of tumor
resectability.
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BETTER VISUALIZATION OF PANCREAS- R. LAT. DECUB.
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ABDOMEN- KIDNEYS
SCOUT AP LANDMARK XIPHOID TIP SCANNING MODE
SPIRAL I.V. CONTRAST 2-4 ml/sec SCAN DELAY1.
NONCONTRAST 2. ARTERIAL 30 SEC. 3.
NEPHROGRAM 90 SEC.
4. EXCRETORY 3-5 MIN. ORAL CONTRAST 400 ml 45
MINUTES BEFORE SCAN, 200 ml JUST BEFORE SCAN
BREATH HOLD SUSPENDED EXPIRATION SLICE
THICKNESS 8-10 MM , 5 MM THROUGH
KIDNEYS START LOCATION LUNG BASES END
LOCATION ILIAC CREST FILMING STANDARD
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• Corticomedullary phase A late arterial phase
  beginning 30 to 40 seconds after the initiation
  of contrast agent administration. Optimal
  enhancement of the renal cortex and renal veins
  occurs during this period. The renal medulla is
  minimally enhanced, allowing for its maximum
  differentiation from the renal cortex.

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Nephrographic phase Time between 70 and 90
seconds after the start of injection. Enhancement
differences between renal cortex and medulla
reach equilibrium, providing optimal sensitivity
for parenchymal lesions. Imaging during the
nephrographic phase also allows for portal
opacification and optimal hepatic enhancement,
which are important for the assessment of disease
spread.
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Excretory phase A delayed imaging phase that
begins approximately 3 minutes after the
initiation of contrast agent administration.
During this phase, the contrast agent has been
excreted into the renal calyces, opacifying the
renal pelvis and the remainder of the urinary
collecting system (ureters, bladder). The
excretory phase best demonstrates the filling
defects and the potential lesions involving the
urothelium.
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Simple cysts Smooth, round, thin-walled masses
with homogeneous near-water CT density (lt20 HU).
An angiomyolipoma of the kidney is a benign mass
of blood vessels (angio-), muscle tissue (myo-),
and fat (lipoma). An ROI measurement of less than
-10 HU characterizes a renal mass as an
angiomyolipoma.
Renal cell carcinoma (RCC) The most common
primary renal malignancy. RCC is typically
characterized by marked contrast enhancement
(gt20-25 HU).
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lt -10
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Transitional cell carcinoma (TCC) A tumor
originating in the urothelium. Most TCCs arise in
the bladder, with the possibility of additional
masses in the ureters, renal pelvis, or both.
On pre-contrast imaging, TCC usually appears as a
hypodense lesion within the renal collecting
system that has a CT density greater than that of
urine but less than that of renal parenchyma (lt40
HU). TCC significantly enhances after
administration of a contrast agent. Metastases
Lung, colon, and breast cancers are primary
malignancies that commonly result in renal
metastases.
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The majority of focal adrenal masses are benign
adenomas. Differentiation between a metastatic
lesion and a benign adenoma is an important goal
of the CT evaluation of an adrenal mass a.On
pre-contrast imaging, ROI measurements of a mass
that are less than 10 HU indicate a benign
process. b.On delayed post-contrast imaging,
metastatic lesions of the adrenal gland remain
enhanced longer than adrenal adenomas. c.The
extent of the dissipation of enhancement, or
washout can be calculated during delayed (10-15
minutes) imaging of the adrenal glands.
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CTA OF THE ABDOMEN
SCOUT AP LANDMARK XIPHOID TIP SCAN MODE
Spiral I.V. CONTRAST 4-5 ml/sec, 100-150
ML SCAN DELAY 25 sec BREATH HOLD SUSPENDED
EXPIRATION SLICE THICKNESS 3 MM START
LOCATION ABOVE AORTIC ARCH END LOCATION BELOW
ILIAC CREST FILMING STANDARD 3D MPR
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ABDOMEN PELVISAPPENDICITIS OR DIVERTICULITIS
SCOUT AP LANDMARK XIPHOID TIP SCAN MODE
Spiral I.V. CONTRAST 1.5-2 ml/sec, 100-150
ML SCAN DELAY 75-80 sec ORAL CONTRAST 500 cc
60-120 MINUTES BEFORE SCAN, 200 ML JUST BEFORE
SCAN BREATH HOLD SUSPENDED EXPIRATION SLICE
THICKNESS 8 MM 3-5MM LOWER START LOCATION
LUNG BASES END LOCATION S.PUBIS FILMING
STANDARD
SCOUT AP LANDMARK XIPHOID TIP SCAN MODE
Spiral I.V. CONTRAST 1.5-2 ml/sec, 100-150
ML SCAN DELAY 75-80 sec ORAL CONTRAST 400 ml
45 MINUTES BEFORE SCAN, 200 ML JUST BEFORE SCAN
BREATH HOLD SUSPENDED EXPIRATION SLICE
THICKNESS 8-10 MM UPPER 5 MM LOWER START
LOCATION LUNG BASES END LOCATION S.
PUBIS FILMING STANDARD
8 MM
5 MM
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CTA ABDOMEN
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CT COLONOSCOPY
2 SCANS- PRONE SUPINE
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PELVIS
SCOUT AP LANDMARK ILIAC CREST SLICE PLANE
AXIAL OR SPIRAL I.V. CONTRAST 1.5-2 ml/sec,
100-120 ml SCAN DELAY 120-180 sec (FULL
BLADDER) ORAL CONTRAST 300-500 ml 1-2 HOURS
BEFORE SCAN 500 cc NIGHT BEFORE BREATH HOLD
SUSPENDED EXPIRATION SLICE THICKNESS 8-10 MM,
3-5 MM IF AP OR
DIVERTICULITIS START LOCATION ILIAC CREST END
LOCATION SYMPHYSIS PUBIS FILMING STANDARD
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DETECTION OF PROSTATE GLAND AND SEMINAL VESICLES
ABNORMALITIES
BLADDER OPACIFIED RECTOSIGMOID COLON AND RECTUM
OPACIFIED
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VISUALIZATION OF VAGINAL CANAL CERVIX AND UTERUS
TAMPON INSERTED IN THE VAGINA DURING CT SCAN OF
THE PELVIS
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