This document discusses the use of ultrasound in evaluating various abdominal emergencies. It outlines that ultrasound is well-suited for the acute abdomen as it is noninvasive, portable, and lacks radiation. Key points include:
- Ultrasound can reliably diagnose acute cholecystitis by identifying gallstones and a positive Murphy's sign. It can also detect complications and non-biliary causes of right upper quadrant pain.
- Ultrasound effectively identifies choledocholithiasis through various imaging planes. It also evaluates other potential causes of pain like liver abscesses, masses, pancreatitis, and renal or vascular issues.
- Common ultrasound findings are discussed for many acute surgical and medical conditions of the
2. The acute abdomen
The acute abdomen is a medical term
used to describe a patient who presents
with sudden onset of severe abdominal
pain sometimes accompanied by nausea,
vomiting, diarrhea, abdominal distension,
and even hypotension or shock.
3. Ultrasound is a well-established imaging
modality for evaluating the abdomen, as it
is noninvasive, portable, readily
obtainable, relatively inexpensive, and
without the risks of ionizing radiation or
iodinated intravenous contrast. In addition,
ultrasound has extremely high diagnostic
accuracy in many clinical scenarios
equivalent or even superior to CT .
4.
5. The biliary tract
The most common cause of acute right upper quadrant
(RUQ) pain in adults is acute cholecystitis. Ultrasound
largely has replaced scintigraphy (HIDA scan) as the
initial imaging modality of choice for evaluating patients
with clinical suspicion of acute cholecystitis,
Furthermore, ultrasound has the additional advantages of
being able to demonstrate potential complications of
acute cholecystitis, such as perforation and gangrene,
and the potential to identify nonbiliary causes of RUQ
pain.
6. The two most important
diagnostic criteria for the
diagnosis of acute cholecystitis
on ultrasound examination are
the presence of gallstones and
a positive sonographic
Murphy's sign. In combination,
these two findings have been
shown by Ralls and colleagues
to have a positive predictive
value of 92% .
Acute Cholecystitis
11. HIV cholangiopathy. hepatitis
Thickening of the gallbladder wall and the presence of peri-cholecystic fluid
are secondary findings of acute cholecystitis
on ultrasound examination, but are neither sensitive nor specific
13. As acute cholecystitis is an obstructive
process, the gallbladder also typically is
distended.
Hence, a careful search should be made for
an obstructing stone in either the cystic
duct or the neck of the gallbladder
18. Choledocholithiasis
Biliary colic should be suspected in patients
with acute RUQ pain who are found to
have small-to-tiny gallstones in a
nondistended gallbladder but no
sonographic Murphy's sign, gallbladder
wall thickening, or peri-cholecystic fluid
19. The sensitivity of ultrasound in detecting
choledocholithiasis has been reported to
range from 70% to 89% in experienced
hands .
Images should be obtained in supine,
semierect, left posterior oblique (LPO) and
right posterior oblique (RPO) positions
using multiple scanning planes .
20.
21. Decubitus or right posterior oblique views can be very helpful in
evaluating the distal common bile duct. Note obstructing echogenic
stone (arrow) in the dilated (1.5 cm) distal common bile duct (calipers).
22. Liver abscess
• On ultrasound, a liver abscess most
commonly appears as a complex cystic
mass with an irregular, shaggy border that
demonstrates increased through
transmission
use tissue harmonic imaging
24. Gray scale image demonstrating a complex hypoechoic
cystic lesion in the liver (calipers). Echogenic material with
dirty distal shadowing represents air in the abscess
look indifferent angles
to avoid impedance from gas
25. Focal liver lesions
• Occasionally patients who have metastatic liver
disease may present with acute RUQ pain.
• In patients who have diffuse metastatic disease,
the pain likely is caused by swelling of the liver
and stretching of the liver capsule .
• Hemorrhage into a liver mass or metastasis,
however, also may cause acute RUQ pain.
Subcapsular hematomas or free intraperitoneal
hemorrhage also may occur following rupture a
liver mass.
27. • Hepatic adenomas, hepatocellular
carcinomas (HCCs), and vascular
metastases are the liver masses most
prone to hemorrhage.
• The risk of rupture is related to size and
location, with larger size and subcapsular
location being risk factors.
• subcapsular hematoma will appear as a
crescentic-shaped area The mass is
typically heterogenous in echotexture.
29. • Spontaneous hemorrhage or rupture has
been estimated to occur in up to 10% of
HCCs .
• An echogenic rind surrounding the liver
has been described as a common finding
in this clinical scenario, representing either
acute hemoperitoneum or subcapsular
hematoma .
32. Pancreas
• It may be difficult to visualize the pancreas in the
setting of acute pancreatitis because of
shadowing from overlying bowel gas and
guarding on examination. In addition, such
patients are typically NPO, and therefore, the
stomach cannot be filled with fluid to provide an
improved acoustic window. Placing the patient in
the RPO or right decubitus position often will
improve visualization of the pancreas, as air in
the duodenum and antrum of the stomach will
rise to the fundus on the left, and the antrum and
duodenum will fill with fluid, providing a better
acoustic window.
tech.hint
34. Oblique view through the right flank in a patient with upper abdominal
pain reveals fluid in the peri-renal space and para-renal space. Note
hypoechoic, thickened para-renal fat linear, hypoechoic plane between
the pancreas (P) and splenic vein/portal confluence .