Surgical Radiology, C30 P183-190 Flashcards by Bea Eus

CHEST
What defines a technically
adequate CXR?
P183

The film must be “RIPE”:
   Rotation: Clavicular heads are
      equidistant from the thoracic
      spinous processes
   Inspiration: Diaphragm is at or below
      ribs 8–10 posteriorly and ribs 5–6
      anteriorly
   Penetration: Disk spaces are visible
      but there is no bony detail of the
      spine; bronchovascular structures
      are seen through the heart
   Exposure: Make sure all of the lung
      fields are visible

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CHEST
How should a CXR be read?
P184

Check the following:
   Tubes and lines: Check placement
   Patient data: Name, date, history
      number
   Orientation: Up/down, left-right
   Technique: AP or PA, supine or
      erect, decubitus
   Trachea: Midline or deviated, caliber
   Lungs: CHF, mass
   Pulmonary vessels: Artery or vein
      enlargement
   Mediastinum: Aortic knob, nodes
   Hila: Masses, lymphadenopathy
   Heart: Transverse diameter should be
      less than half the transthoracic
      diameter
   Pleura: Effusion, thickening,
      pneumothorax
   Bones: Fractures, lesions
   Soft tissues: Periphery and below the
      diaphragm

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CHEST
What CXR is better: P-A or A-P?
P184

P-A, less magnification of the heart (heart

is closer to the x-ray plate)

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CHEST
Classically, how much pleural
fluid can the diaphragm
hide on upright CXR?
P184

It is said that the diaphragm can

overshadow up to 500 cc

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CHEST
How can CXR confirm that
the last hole on a chest tube
is in the pleural cavity?
P184

Last hole is through the radiopaque line
on the chest tube; thus, look for the break
in the radiopaque line to be in the rib cage

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CHEST
How can a loculated pleural
effusion be distinguished from
a free-flowing pleural effusion?
P184

Ipsilateral decubitus CXR; if fluid is not

loculated (or contained), it will layer out

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CHEST
How do you recognize a
pneumothorax on CXR?
P184

Air without lung markings is seen outside
the white pleural line—best seen in the
apices on an upright CXR

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CHEST
What x-ray should be obtained
before feeding via a nasogastric
or nasoduodenal tube?
P184

Low CXR to ensure the tube is in the GI

tract and not in the lung

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CHEST
What C-spine views are used
to rule out bony injury?
P184

CT scan

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CHEST
What is used to look for
ligamentous C-spine injury?
P185

Lateral flex and extension C-spine films,

MRI

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CHEST
What CXR findings may
provide evidence of
traumatic aortic injury?
P185

Widened mediastinum 8 cm (most
   common)
Apical pleural capping
Loss of aortic knob
Inferior displacement of left main
   bronchus; NG tube displaced to the
   right, tracheal deviation, hemothorax

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CHEST
How should a CT scan be
read?
P185 (picture)

Cross section with the patient in supine

position looking up from the feet

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ABDOMEN
How should an abdominal
x-ray (AXR) be read?
P185

Check the following:
   Patient data: name, date, history
      number
   Orientation: up/down, left-right
   Technique: A-P or P-A, supine or
      erect, decubitus
   Air: free air under diaphragm,
      air-fluid levels
   Gas dilatation (3, 6, 9 rule)
   Borders: psoas shadow, preperitoneal
      fat stripe
   Mass: look for organomegaly, kidney
      shadow
   Stones/calcification: urinary, biliary,
      fecalith
   Stool
   Tubes
   Bones
   Foreign bodies

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ABDOMEN
How can you tell the
difference between a small
bowel obstruction (SBO) and
an ileus?
P186

In SBO there is a transition point
(cut-off sign) between the distended
proximal bowel and the distal bowel of
normal caliber (may be gasless), whereas
the bowel in ileus is diffusely distended

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ABDOMEN
What is the significance of
an air-fluid level?
P186 (picture)

Seen in obstruction or ileus on an upright
x-ray; intraluminal bowel diameter
increases, allowing for separation of fluid
and gas

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ABDOMEN
What are the normal
calibers of the small bowel,
transverse colon, and
cecum?
P186

Use the “3, 6, 9 rule”:
Small bowel 6 cm
Cecum

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ABDOMEN
What is the “rule of 3s” for
the small bowel?
P186

Bowel wall should be

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ABDOMEN
How can the small and large
bowel be distinguished on
AXR?
P186

By the intraluminal folds: The small
bowel plicae circulares are complete,
whereas the plicae semilunares of the
large bowel are only partially around the
inner circumference of the lumen

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ABDOMEN
Where does peritoneal fluid
accumulate in the supine
position?
P186

Morison’s pouch (hepatorenal recess), the
space between the anterior surface of the
right kidney and the posterior surface of
the right lobe of the liver

ABDOMEN
What percentage of kidney
stones are radiopaque?
P186

≈90%

ABDOMEN
What percentage of
gallstones are radiopaque?
P187

≈10%

ABDOMEN
What percentage of patients
with acute appendicitis have
a radiopaque fecalith?
P187

≈5%

ABDOMEN
What are the radiographic
signs of appendicitis?
P187

Fecalith; sentinel loops; scoliosis away
from the right because of pain; mass
effect (abscess); loss of psoas shadow;
loss of preperitoneal fat stripe; and, very
rarely, a small amount of free air, if
perforated

ABDOMEN
What does KUB stand for?
P187

Kidneys, Ureters, and Bladder—
commonly used term for a plain film
AXR (abdominal flat plate)

ABDOMEN What is the “parrot’s beak” or “bird’s beak” sign? P187

Evidence of sigmoid volvulus on barium enema; evidence of achalasia on barium swallow

ABDOMEN What is a “cut-off sign”? P187

Seen in obstruction, bowel distention, and distended bowel that is “cut-off” from normal bowel

ABDOMEN What are “sentinel loops”? P187

Distention or air-fluid levels (or both) near a site of abdominal inflammation (e.g., seen in RLQ with appendicitis)

ABDOMEN What is loss of the psoas shadow? P187

Loss of the clearly defined borders of the psoas muscle on AXR; loss signifies inflammation or ascites

``` ABDOMEN What is loss of the peritoneal fat stripe (a.k.a. preperitoneal fat stripe)? P187 ```

Loss of the lateral peritoneal/preperitoneal | fat interface; implies inflammation

ABDOMEN What is “thumbprinting”? P187

Nonspecific colonic mucosal edema | resembling thumb indentations on AXR

ABDOMEN What is pneumatosis intestinalis? P187

Gas within the intestinal wall (usually means dead gut) that can be seen in patients with congenital variant or chronic steroids

ABDOMEN What is free air? P188 (picture)

Air free within the peritoneal cavity (air or gas should be seen only within the bowel or stomach); results from bowel or stomach perforation

``` ABDOMEN What is the best position for the detection of FREE AIR (free intraperitoneal air)? P188 ```

Upright CXR—air below the right | diaphragm

``` ABDOMEN If you cannot get an upright CXR, what is the second best plain x-ray for free air? P188 ```

Left lateral decubitus, because it prevents confusion with gastric air bubble; with free air both sides of the bowel wall can be seen; can detect as little as 1 cc of air

ABDOMEN How long after a laparotomy can there be free air on AXR? P188

Usually 7 days or less

ABDOMEN What is Chilaiditi’s sign? P188

Transverse colon over the liver simulating | free air on x-ray

``` ABDOMEN When should a postoperative abdominal/pelvic CT scan for a peritoneal abscess be performed? P188 ```

POD #7 or later, to give time for the | abscess to form

``` ABDOMEN What is the best test to evaluate the biliary system and gallbladder? P188 ```

Ultrasound (U/S)

``` ABDOMEN What is the normal diameter of the common bile duct with gallbladder present? P189 ```

``` ABDOMEN What is the normal common bile duct diameter after removal of the gallbladder? P189 ```

8 to 10 mm

``` ABDOMEN What U/S findings are associated with acute cholecystitis? P189 ```

Gallstones, thickened gallbladder wall ( >3 mm), distended gallbladder ( >4 cm A-P), impacted stone in gallbladder neck, pericholecystic fluid

ABDOMEN What type of kidney stone is not seen on AXR? P189

Uric acid (Think: Uric acid = Unseen)

``` ABDOMEN What medication should be given prophylactically to a patient with a true history of contrast allergy? P189 ```

``` Methylprednisolone or dexamethasone; the patient should also receive nonionic contrast (associated with one fifth as many reactions as ionic contrast, the less expensive standard) ```

ABDOMEN What is a C-C mammogram? P189 (picture)

Cranio-Caudal mammogram, in which | the breast is compressed top to bottom

ABDOMEN What is an MLO mammogram? P190 (picture)

MedioLateral Oblique mammogram, in which the breast is compressed in a 45˚ angle from the axilla to the lower sternum

``` ABDOMEN What are the best studies to evaluate for a pulmonary embolus? P189 ```

``` Spiral thoracic CT scan, V-Q scan, pulmonary angiogram (gold standard) ```