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Emergency
Medicine Atlas > Part 2. Specialty
Areas > Chapter 19. Emergency Ultrasound >
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Emergency Ultrasound
Emergency medicine ultrasound has
the basic goal of improving patient care. This chapter strives to provide
a "visual blueprint" for the reader who uses emergency medicine
ultrasonography in his or her practice. It is intended to serve as a
practical imaging reference when an emergency screening ultrasound
examination is being performed and assumes a basic knowledge and
experiential base in ultrasound examinations. For practitioners without
this prerequisite body of knowledge, it may provide useful information
about the scope of the emergency screening ultrasound examination (ESUE).
Success in performing an ESUE is
dependent on the physician's goal-directed approach to each examination.
This demands that the physician use ultrasound to identify, confirm, or
exclude specific sonographic findings that are consistent with specific
disease states or life-threatening conditions.
Basic ultrasound
information—including transducer recommendations, scanning
protocols, anatomic schematics, and ultrasound images—are presented
throughout the chapter. Applicable protocols are patterned after imaging
guidelines of the American Institute of Ultrasound in Medicine as well as
the authors' collective experiences. The issues of the efficacy,
accuracy, and/or sensitivity of this modality are not debated; rather, a
"visual blueprint" for ESUEs is provided. Once again, this
chapter is not presented as a primary instructional tool, but rather as a
rapid visual review for the physician trained in ESUE applications.
Information is presented about
the following ESUE protocols:
1. Trauma: focused assessment
with sonography for trauma (FAST)
2. Cardiac: echocardiography
(ECHO)
3. Abdominal (gallbladder,
aorta, and kidney)
4. Pelvic/endovaginal
Transducers
Sonography is performed using
transducers of varying frequencies. Lower or higher frequencies are
selected for more or less depth of penetration. Many manufacturers produce
multifrequency transducers available with small or large footprints. The
various transducers recommended for use in the ESUE are listed below
(Fig. 19.1).
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Transducers Various transducers recommended for use in the
emergency screening ultrasound exam (ESUE). A. Microconvex. B.
Convex array. C. Phased array. D. Mechanical sector. E.
Linear. (A, B, and E, Courtesy of SonoSite,
Inc.; C and D, Courtesy of Windy City Ultrasound,
Inc..)
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 Microconvex:
This transducer has the advantage of a tight curvature and small
footprint that allows for easy access between ribs and for subxiphoid
imaging. This is an excellent transducer for the FAST, especially for the
beginner, who may have difficulty scanning or interpreting with rib
shadowing present. This probe is also helpful in the thin patients with a
high-positioned gallbladder requiring intercostal windows for optimal
imaging. These transducers are generally more expensive than the standard
curve-linear transducer.
Convex
Array: Considered a standard abdominal transducer, it is used by many
sonographers and provides wide near and far fields of view (ideal in
evaluating the aorta). The long curved footprint of this type of
transducer may make subxiphoid cardiac imaging difficult, as will the
noted presence of "rib shadowing," which is inevitable with
this transducer in scanning the right/left upper quadrants in the coronal
plane. This is the transducer of choice for imaging the gallbladder at a
frequency of 3.5 MHz; it is used by many vascular laboratories in
evaluating the abdominal aorta. It is also the preferred transducer for
renal ultrasound.
Phased
Array: This transducer is the transducer of choice for cardiac
ultrasound. It results in a narrow near field of view. The image obtained
is a true "pie-shaped" image. As a result, the phased array
often has a small, flat footprint and is easy to maneuver between ribs.
These transducers are frequently marketed in the 2.0- to 4.0-MHz ranges
and will yield less resolution than the curved array transducers of
higher frequencies. The advantage of this transducer is in scanning the obese
patient who may be difficult to image during the FAST examination. The
disadvantage is that the image quality is slightly less than that of
geometrically steered (linear and curved array) transducers of the same
frequency. This is not the preferred transducer for transabdominal pelvic
sonography.
Mechanical
Sector: Many manufacturers still produce mechanical sector
transducers. These provide a small footprint with a pie-shaped image and
are usually much less expensive than phased-array transducers. Mechanical
transducers are more likely to wear over time and tend to be less
tolerant to incidental impacts (a common occurrence in the ED).
Linear:
This transducer is frequently used for superficial structures and
vascular ultrasound. It usually is available in frequencies ranging from
5.0 MHz upward. It can be helpful in the very thin patient or the patient
with an extremely superficial gallbladder.
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Trauma Ultrasound
The focused assessment with
sonography for trauma (FAST) is an organized series of sonographic
windows or views that attempts to identify the presence or absence of
fluid in anatomic potential spaces (e.g., pericardium or Morison's pouch)
or anatomically dependent areas (e.g., pelvis, posteroinferior thorax,
and splenorenal recess). It is, in fact, a cardiac and thoracoabdominal
survey that allows the physician to identify or exclude immediate or
potential life threats in the trauma patient. Though intended for the
evaluation of the traumatized patient, the FAST examination and its
components are also extremely valuable in the evaluation of several emergent
complaints and clinical conditions.
Clinical Indications for the
FAST Examination
Blunt
abdominal trauma
Penetrating
thoracic/abdominal trauma
Unexplained
hypotension (trauma and nontrauma)
Evaluation
of the pregnant trauma patient
Acute
dyspnea with suspected pleural/pericardial effusion or tamponade
In its simplest form, the FAST
examination uses four primary sonographic windows to evaluate the
patient. It is recommended that these windows be scanned in sequence, but
isolated views may be obtained when indicated (e.g., suspected pleural
effusions in the dyspneic patient).
Required Views for the FAST
Examination
1. Subxiphoid-cardiac window
(subcostal view)
2. Right upper quadrant
(Morison's pouch)
3. Left upper quadrant
(splenorenal view)
4. Suprapubic window (pelvic view)
Recommended Transducers for the
FAST Examination
Microconvex
Convex
array
Phased
array
Most abdominal sonography is
performed using transducers of 3.5 to 5.0 MHz. The FAST examination is an
echocardiographic and thoracoabdominal examination. This presents the
dilemma of using a transducer that can image all three of these areas but
only with some sonographic compromise.
FAST Window 1:
Subxiphoid-Cardiac (Subcostal View)
Technique
The
patient is supine.
The
transducer is directed under the xiphoid process toward the left shoulder
in a horizontal plane (Fig. 19.2).
Direct
the transducer indicator to the patient's right.
Pivot,
sweep, and tilt the transducer to view of all four cardiac chambers.
Identify
the heart, four cardiac chambers, and surrounding pericardium (Fig.
19.3).
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Subxiphoid-Cardiac
View The transducer is
directed under the xiphoid process toward the left shoulder in a
horizontal plane. (Courtesy of Michael J. Lambert, MD, RDMS.)
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Subxiphoid-Cardiac
View The heart, four cardiac
chambers, and surrounding percicardium are seen in this view.
(Courtesy of Michael J. Lambert, MD, RDMS.)
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Abnormal Findings
Hemopericardium
(pericardial effusion): Dark black, anechoic region noted between the
bright pericardium and the walls of the heart (occasionally internal
echoes representing fibrin, clot, or cardiac tissue may be present) (Fig.
19.4).
Asystole:
No cardiac activity present.
Hyperdynamic
cardiac activity: Extensive cardiac contraction with maximal collapse of
the cardiac chambers, often associated with tachycardia and hypovolemia.
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Hemopericardium The dark black, anechoic region between the
bright pericardium and the walls of the heart represents a
pericardial effusion. (Courtesy of Paul R. Sierzenski, MD, RDMS,
FAAEM.)
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FAST Window 2: Right Upper
Quadrant (Morison's Pouch)
Technique
The
patient is supine.
The
transducer indicator is aimed toward the axilla in a coronal plane.
The
transducer is directed as a coronal section through the body in the
midaxillary line, extending from the 9th through 12th ribs. Start between
the 11th and 12th ribs initially, then move cephalad or caudal to
complete the evaluation (Fig. 19.5).
Identify
the liver and right kidney interface. This region is the potential space
known as Morison's pouch. Normally, these organs' surrounding tissues are
in direct contact with one another (Fig. 19.6).
Evaluate
the right diaphragmatic recess and the subdiaphragmatic recess.
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Right
Upper Quadrant The transducer
is directed as a coronal section through the body in the midaxillary
line extending from the 9th through 12th ribs. (Courtesy of Windy
City Ultrasound, Inc.)
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Normal
Right Upper Quadrant (Morison's Pouch) At the liver and right kidney interface is the
potential space known as "Morison's pouch." Normally the
surrounding tissues of these organs are in direct contact with one
another. (Courtesy of Windy City Ultrasound, Inc.)
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Abnormal Findings
Hemoperitoneum:
Dark black, anechoic region between the liver and right kidney or in the
subdiaphragmatic recess (Fig. 19.7). May be positive with a ruptured ectopic
pregnancy.
Right
hemothorax: Anechoic (dark) region above the level of the diaphragm.
Solid
organ injury: Solid organ injury such as hepatic and renal lacerations as
well as organ rupture have been described but are beyond the scope of
this chapter.
Hydronephrosis:
Dilatation of the renal sinus with dark, anechoic fluid within the bright
renal sinus (see "Renal Ultrasound," below).
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Hemoperitoneum
(Morison's Pouch) The dark
black, anechoic region between the liver and right kidney or in the
subdiaphragmatic recess represents fluid in Morison's pouch.
(Courtesy of Michael J. Lambert, MD, RDMS.)
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FAST Window 3: Left Upper
Quadrant (Splenorenal View)
Technique
The
patient is supine.
The
transducer indicator is directed toward the axilla in a coronal plane.
The
transducer is directed as a coronal section through the body in the
midaxillary to posterior axillary line extending from the 9th through
12th ribs. Start between the 11th and 12th ribs initially, then move
cephalad or caudal to complete the evaluation (Fig. 19.8).
Identify
the spleen and left kidney interface. This region is a physiologic
potential space. Normally the surrounding tissues of these organs are in
direct contact with one another (Fig. 19.9).
Evaluate
the left diaphragmatic recess and the left subdiaphragmatic recess.
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Left
Upper Quadrant (Splenorenal View)
The transducer is directed as a coronal section through the body in
the midaxillary line extending from the 9th through 12th ribs.
(Courtesy of Windy City Ultrasound, Inc.)
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Normal
Left Upper Quadrant (Splenorenal View) The spleen and kidney interface is a
physiologic potential space (splenorenal recess). Normally the
surrounding tissues of these organs are in direct contact with one
another. (Courtesy of Paul R. Sierzenski, MD, RDMS, FAAEM.)
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Abnormal Findings
Hemoperitoneum:
Anechoic (dark) region between the spleen and left kidney or between the
spleen and the diaphragm (Fig. 19.10).
Left
hemothorax: Dark black, anechoic region above the level of the diaphragm
(Fig. 19.11).
Solid
organ injury: Solid organ injury such as splenic and renal lacerations as
well as organ rupture have been described but are beyond the scope of
this chapter.
Hydronephrosis:
Dilatation of the renal sinus with dark black, anechoic fluid within the
bright renal sinus (see "Renal Ultrasound," below).
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Hemoperitoneum
(Splenorenal View) The
anechoic area above the spleen and left kidney or between the spleen
and the diaphragm represents fluid in the potential space. This image
represents fluid above the spleen but below the level of the
diaphragm. (Courtesy of Michael J. Lambert, MD, RDMS.)
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Right
Hemothorax Fluid above
the level of the diaphragm represents a hemothorax. (Courtesy of
Michael J. Lambert, MD, RDMS.)
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FAST Window 4: Suprapubic
Technique
Sagittal View (Longitudinal)
The
patient is supine.
The
transducer is placed just above the symphysis pubis.
The
transducer is directed into the pelvis with the transducer indicator
oriented toward the patient's head (Fig. 19.12).
Identify
the bladder (triangular in this view when fully distended), uterus
(pear-shaped if present), and rectum (Fig. 19.13).
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Suprapubic
Sagittal View The transducer
is directed with the transducer indicator oriented toward the
patient's head and placed just superior to the symphysis pubis.
(Courtesy of Windy City Ultrasound, Inc.)
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Suprapubic
Sagittal View In this view,
when fully distended, the bladder is triangular in shape. If present,
the uterus is pear-shaped. Fluid may collect in the vesicouterine (V)
(potential space seen between the bladder and uterus in this view)
and/or rectouterine (D) (pouch of Douglas) (space seen posterior to
the border of the uterus and rectum) pouches. (Courtesy of Windy City
Ultrasound, Inc.)
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Transverse View
The
patient is supine.
The
transducer is placed about 1 to 2 cm above the symphysis pubis.
The
transducer is directed with the transducer indicator oriented toward the
patient's right, with the beam angled caudally into the pelvis (Fig.
19.14).
Identify
the bladder (rectangular in this view when fully distended), uterus (oval
hyperechoic structure if present) and rectum (Fig. 19.15).
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Suprapubic
Transverse View The transducer
indicator is oriented toward the patient's right and the beam angled
caudally into the pelvis. (Courtesy of Windy City Ultrasound, Inc.)
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Suprapubic
Transverse View In this view,
the bladder assumes a rectangular shape when fully distended. If
present, the uterus is an oval hyperechoic structure. (Courtesy of
Windy City Ultrasound, Inc.)
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Abnormal Findings
Hemoperitoneum:
Anechoic (dark) regions between the bladder and uterus or the uterus and
rectum or as loops of bowel floating lateral to the bladder in the
transverse view and lateral or superior to the bladder in the sagittal
view (Fig. 19.16).
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Hemoperitoneum Hemoperitoneum can be seen as dark black,
anechoic regions between the bladder and uterus, as well as the
uterus and rectum or as loops of bowel floating lateral to the
bladder in the transverse view and lateral or posterior to the
bladder in the sagittal view. (Courtesy of Paul R. Sierzenski, MD,
RDMS, FAAEM.)
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Scan Pearls for the FAST
Examination
Subxiphoid-Cardiac
1. When your view is obscured
by gas, slide the transducer slightly to the patient's right subcostal
region, using the liver as an echogenic window.
2. If you are unable to view
the heart in the true subxiphoid or subcostal window, move to a
parasternal long axis view (see "Cardiac Ultrasound (ECHO),"
below).
3. A frequent mistake in
imaging is to direct the transducer toward the spine rather than
coronally to the shoulder. You will often require less than a 30 degree
angle between the transducer and the skin.
4. Start imaging with the
depth/scale setting at its maximum (e.g., 20 to 24 cm). This should allow
you to image the anterior and posterior pericardium in your initial view.
Gradually decrease the depth/scale (e.g., 14 to 18 cm) to fill the entire
sector image with the heart as you continue to optimize your image.
RUQ and LUQ
1. The diaphragmatic recess
includes a superior region, which is the inferior border of the
right thorax, and an inferior region (subdiaphragmatic recess),
which is the superior border of the abdomen. Fluid in the diaphragmatic
recess can represent a hemothorax when located superior/cephalad to the
diaphragm or a hemoperitoneum or subphrenic hematoma (inferior to the
diaphragm) in the setting of trauma.
2. Identify the kidneys from
the superior to the inferior poles in the coronal plane. It may seem
easier at first to perform a short axis view; however, the sonographer
risks missing early small fluid collections if only a middle renal
transverse section is imaged.
3. If you are uncertain whether
a finding is actually present, evaluate it in a second plane. To do this,
turn the transducer 90 degrees from your initial transducer position and
see if the finding is still noted on the image.
4. It is important to note that
the LUQ is not synonymous to the RUQ; the spleen is not tethered to the
diaphragm as the liver is by the coronary ligament. Sonographically we
tend to see fluid collect in the left subdiaphragmatic area more than the
right. This area should be evaluated.
Suprapubic
1. It is important to remember
that the bladder is within the pelvis; therefore the transducer must be
directed posteriorly and inferiorly to image the bladder and its
neighboring structures.
2. When in the sagittal plane,
simply rotate the transducer 90 degrees counterclockwise with the
transducer indicator oriented to the patient's right, and you will
transition to a transverse view.
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Cardiac Ultrasound (ECHO)
Two-dimensional echocardiography
(2D ECHO) can yield significant diagnostic information for the patient
presenting with cardiac arrest, shock, shortness of breath, and a host of
other complaints or physical findings. Although the physician can easily
become intimidated by all the diagnostic possibilities that can be
identified or potentially missed in performing echocardiography, one can,
with experience, incorporate ED ECHO into the diagnostic armamentarium
without becoming overextended.
It is important to note that,
unlike abdominal sonography, cardiac ultrasound is by convention oriented
with the transducer indicator for the display screen to the right of the
screen (which will effectively be the patient's left). This may be a
significant cause of initial confusion for many who have not performed
echocardiography before. Most ultrasound systems today include cardiac
presets that automatically reverse the orientation to the right of the
display screen. The following section describes a sonographic approach
for a correctly oriented image using standard cardiac windows.
Clinical Indications for ED
Cardiac Ultrasound (ECHO)
Cardiac
arrest, PEA
Penetrating
thoracic/abdominal trauma
Unexplained
hypotension or shock
Dyspnea
Acute
myocardial infarction
Suspected
aortic dissection
Specific pathologic states
confirmed or excluded with ED ECHO include asystole (confirmation),
cardiac activity (confirmation), pericardial effusion, and aortic root
dilatation/dissection.
The sonographic windows for ED
ECHO act as an extension of the subxiphoid view presented within the
trauma/FAST examination. The ED ECHO utilizes cardiac windows that are
familiar to cardiologists and sonographers alike. The four ED ECHO
windows will allow the emergency physician to evaluate asystole,
pericardial effusions, and the aortic root.
Required Views for Emergency
Department ECHO
1. Subxiphoid (subcostal) (see
"FAST Examination," above)
2. Parasternal long-axis view
(PSLAx)
3. Parasternal short-axis view
(PSSAx)
4. Apical four-chamber view
(A4C)
Recommended Transducers for ECHO
Phased
array
Microconvex
Mechanical
sector
ECHO Window 1:
Subxiphoid-Cardiac (Subcostal View)
Technique
The
patient is supine.
The
transducer is placed inferior to the xiphoid process and directed toward
the left shoulder in a horizontal plane. (The transducer indicator should
be directed in the same orientation as the indicator mark of the screen;
this is frequently to the patient's right in an abdominal preset, but it
is toward the left in a cardiac preset) (see Fig. 19.2).
Pivot,
sweep, and tilt the transducer to view all four cardiac chambers.
Identify
the heart, four cardiac chambers, and surrounding pericardium (see Fig.
19.3).
Abnormal Findings
Hemopericardium
(pericardial effusion): Anechoic (dark) region noted between the bright
pericardium and the walls of the heart (occasionally internal echoes
representing, fibrin, clot, or cardiac tissue may be present) (see Fig.
19.4).
Asystole:
No cardiac activity present.
Hyperdynamic
cardiac activity: Extensive cardiac contraction with maximal collapse of
the cardiac chambers, often associated with tachycardia.
Scan Pearls for
Subxiphoid-Cardiac
See
"Scan Pearls for the FAST Examination," above.
ECHO Window 2: Parasternal
Long-Axis View (PSLAx)
Technique
This assumes a leftward image
orientation—e.g., transducer indicator to the right of the screen.
This will effectively be toward the patient's head.
The
patient is supine or in the left lateral decubitus (LLD) position with
the left arm extended above the head for easier transducer access.
The
transducer is placed in the fourth or fifth left parasternal intercostal
space with the transducer indicator directed at the right clavicle or
shoulder (Fig. 19.17).
Identify
the right ventricle, left atrium, left ventricle, aortic valve, aortic
root, aortic outflow tract, and surrounding pericardium (Fig. 19.18).
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Parasternal
Long-Axis View The transducer
is placed in the fourth or fifth left parasternal intercostal space
with the transducer indicator oriented toward the right clavicle or
shoulder. (Courtesy of Windy City Ultrasound, Inc.)
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Parasternal
Long-Axis View The left
atrium, left ventricle, aortic valve, aortic root, aortic outflow
tract, and surrounding pericardium can be visualized. (Courtesy of
Michael J. Lambert, MD, RDMS.)
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Abnormal Findings
Hemopericardium:
Anechoic (dark) region noted between the hyperechoic (bright) pericardium
and the walls of the heart (see Fig. 19.4).
Aortic
root dilatation: An aortic root measurement greater than 3.8 cm is
abnormal and should suggest either aortic dissection or aneurysm in the
emergency patient with chest pain or back pain or in the appropriate
clinical setting. Further evaluation is recommended.
Dilated
descending aorta: The descending thoracic aorta can be seen in the far
field in this view posterior to the left atrium. A descending thoracic
aorta greater than 3.8 cm is suspicious for aneurysm or dissection and
requires further evaluation.
Scan Pearls for the Parasternal
Long-Axis View
1. A true parasternal long-axis
view (a sagittal image through the heart) will visualize the aortic root
within the image. If the aortic root is not present, you are likely in an
oblique plane and will need to gently angle the transducer in either
direction to optimize the image.
2. It is critical to make
deliberate, slow, small adjustments of the transducer in imaging the
heart, since even small movements at the skin surface can translate into
large changes in beam angle at just 5 to 10 cm deep from the surface.
3. Normal spontaneous
respiration is usually fine for cardiac imaging. Patients who are
tachypneic can be very challenging, and verbally coaching the patient's
breathing patterns is best. If you note a great deal of artifact due to
lung interposition, place the patient in the left lateral decubitus
position; have him or her inhale and slowly exhale while you scan. When
you have an acceptable window, ask the patient to stop exhaling and hold
his or her breath while you capture your images.
4. Remember that the
parasternal long axis is approximated by a line running from the right
acromioclavicular joint and the left antecubital fossa (when the arm is
lying by the patient's side).
ECHO Window 3: Parasternal
Short-Axis View (PSSAx)
Technique
This assumes a leftward image
orientation—e.g., transducer indicator to the right of the screen.
This will effectively be toward the patient's head.
The
patient is supine or in the left lateral decubitus position.
From the
parasternal long-axis position, rotate the transducer 90 degrees
clockwise (to the patient's left) or place the transducer in the fourth
or fifth left parasternal intercostal space in a line connecting the left
clavicle/shoulder and the right hip (Fig. 19.19).
Identify
the left ventricle (circular), right ventricle (crescent-shaped), and
surrounding pericardium (Fig. 19.20).
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Parasternal
Short-Axis View From the
parasternal long-axis position, rotate the transducer 90 degrees
clockwise (to the patient's left) or place the transducer in the
fourth or fifth left parasternal intercostal space in a line
connecting the left clavicle/shoulder and the right hip. (Courtesy of
Windy City Ultrasound, Inc.)
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Parasternal
Short-Axis View The left
ventricle (circular), right ventricle (crescent-shaped), aortic
valve, and surrounding pericardium can be identified. (Courtesy of
Paul R. Sierzenski, MD, RDMS, FAAEM.)
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Abnormal Findings
Hemopericardium:
Dark black, anechoic region noted between the bright pericardium and the
walls of the heart (see Fig. 19.4).
Dilated
right ventricle: The right ventricle is normally a crescent-shaped
structure; if this is a rounded, dilated structure, it suggests elevated
right-sided pressures, as seen with pulmonary emboli and severe pulmonary
hypertension.
Scan Pearls for the Parasternal
Short-Axis View
1. The standard parasternal
short-axis view is obtained with the image plane at the level of the
papillary muscles. Visualization of the papillary muscles should ensure a
true transverse section through the left ventricle and provides a prime
location for the evaluation of left ventricular contraction and motion.
ECHO Window 4: Apical
Four-Chamber View (A4C)
Technique
This assumes that a leftward
image orientation is the standard sonographic approach.
The
patient is supine or in the left lateral decubitus position.
The
transducer is placed over the cardiac apex or the point of maximal
intensity (PMI) with the beam directed toward the right clavicle/shoulder
in a plane coronal to the heart. The transducer indicator is directed
toward the left axilla (Fig. 19.21).
Identify
the left ventricle, right ventricle, left atrium, right atrium, and
surrounding pericardium (Fig. 19.22).
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Apical
Four-Chamber View The
transducer is placed over the cardiac apex or the point of maximal
intensity, with the beam directed toward the right clavicle/shoulder
in a plane coronal to the heart. The transducer indicator is directed
toward the left axilla. (Courtesy of Windy City Ultrasound, Inc.)
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Apical
Four-Chamber View The right
ventricle (RV), left ventricle (LV), right atrium (RA), left atrium
(LA), and surrounding pericardium are visualized in this view.
(Courtesy of Paul R. Sierzenski, MD, RDMS, FAAEM.)
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Abnormal Findings
Hemopericardium:
Anechoic (dark) region noted between the hyperechoic pericardium and the
walls of the heart (see Fig. 19.4).
Dilated
right atria/ventricle: If the right atria/ventricle are rounded or appear
rigid and poorly contracting, this may suggest elevated right-sided
pressures as seen with pulmonary emboli and severe pulmonary
hypertension.
Scan Pearls for Apical
Four-Chamber View
1. See "Scan Pearls for
the FAST Examination, Subxiphoid-Cardiac," item 4, above.
2. It is critical to realize
the variance in the resting position of the heart. It is evident, using
this view, that there can be relatively significant differences and
acoustic windows from patient to patient with the four-chamber apical
view.
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Abdominal Ultrasound
The application of abdominal
ultrasound in emergency medicine seems, for many physicians,
self-evident. Abdominal aortic aneurysm (AAA), gallbladder disease, and
renal colic are all common diagnoses in patients presenting to the ED.
The ability to rapidly diagnose or exclude these disease states can
decrease patient morbidity and mortality. The abdominal emergency
screening ultrasound examination (ESUE) can aid in this diagnostic
process.
The clinical indications for an
abdominal ESUE may vary with each ED and ED physician. There are three
specific pathologic states that we believe the proficient emergency
physician should be able to identify: AAA, gallstones, and hydronephrosis.
This series on abdominal ESUE presents the applications of gallbladder,
aortic and renal ultrasound.
Required Views for Abdominal
Ultrasound
1. Gallbladder (sagittal,
transverse, oblique views)
2. Aorta (transverse, sagittal
views)
3. Renal (coronal, sagittal
views)
Gallbladder Ultrasound
Ultrasound of the gallbladder can
be among the most rewarding ESUEs to perform. Patients can receive a
rapid focused ultrasound to determine if gallstones or gallbladder
pathology is the etiology of their pain or presenting symptoms, and they
are often relieved to be given a visual presentation of their illness. No
ESUE calls for more careful positioning of the patient than the
gallbladder and biliary ultrasound. Position the patient to minimize
bowel gas from your view, accentuate possible pathology, and verify
suspected findings. This can be a technically difficult ultrasound to
perform.
Clinical Indications for
Gallbladder Ultrasound
Right-upper-quadrant
pain
Jaundice/icterus
Epigastric
pain
It is important to recognize the
limited nature of gallbladder ultrasounds performed by emergency
physicians. Thorough evaluation of the biliary tract is a routine
component of a standard radiology abdominal ultrasound but can be technically
and diagnostically difficult, especially in the patient with acute pain.
For this reason, measurement of the hepatic and common bile ducts is not
included as an initial key component to the basic gallbladder ESUE.
Techniques for measurement of the common bile duct are reviewed below;
these should be performed by an emergency physician proficient in
abdominal ultrasound. Although the sonographic identification of
gallstones may seem straightforward, the sonographic findings for
cholecystitis can frequently be subtle.
Recommended Transducers for
Gallbladder Ultrasound
Convex
array
Microconvex
Phased
array
Mechanical
sector
Most abdominal sonography is
performed using transducer frequencies of 3.5 to 5.0 MHz. In rare
instances, lower or higher frequencies are needed for more or less depth
of penetration.
Gallbladder Ultrasound Window 1:
Sagittal View
Technique
The
patient is supine or in the left lateral decubitus position. Other
positions—including prone, right lateral decubitus, semierect, and
standing—may be helpful in scanning the gallbladder.
The
transducer is placed in the subxiphoid region with the orientation
indicator directed toward the patient's head and swept below the right
costal margin to approximately the midclavicular line (Figs. 19.23,
19.24).
Identify
the liver, portal vein, common bile duct, hepatic artery, gallbladder,
and main lobar fissure (spanning these two structures). Measure the
thickness of the common bile duct when able (Fig. 19.25).
Scan
through the gallbladder completely from the medial to lateral borders of
the gallbladder.
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Gallbladder:
Sagittal View The transducer
is placed in the subxiphoid region with the orientation indicator
directed toward the patient's head and moved along the right costal
margin approximately to the midclavicular line. (Courtesy of Windy
City Ultrasound, Inc.)
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Gallbladder:
Sagittal View Various
structures can be seen in this sagittal view. Although not apparent
in the drawing, the gallbladder and portal vein are within the liver.
Moving the patient to the left lateral decubitus position may improve
this view. (Courtesy of Windy City Ultrasound, Inc.)
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Gallbladder Ultrasound Window 2:
Transverse View
Technique
The
patient is supine or in the left lateral decubitus position.
From the
sagittal position, rotate the transducer 90 degrees counterclockwise to
the patient's right and move along the right costal margin (Fig. 19.26).
Identify
the liver, gallbladder, inferior vena cava, right kidney (if visualized),
and common bile duct (if visualized) (Figs. 19.27, 19.28, and 19.29).
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Gallbladder:
Transverse View The transducer
is rotated 90 degrees counterclockwise from the sagittal position and
moved along the right costal margin. (Courtesy of Windy City
Ultrasound, Inc.)
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Gallbladder:
Transverse View Various
structures can be seen in this transverse view. (Courtesy of Windy
City Ultrasound, Inc.)
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Gallbladder:
Portal Triad The portal triad
(portal vein, common bile duct, and hepatic artery) is readily seen
in this transverse view. Although not apparent in the drawing, these
structures are within the liver (A). Color-flow Doppler (B)
facilitates identification of these structures. (Courtesy of Windy
City Ultrasound, Inc.)
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Gallbladder:
Common Bile Duct (CBD) The CBD
is seen in this transverse view. Once it is identified, its thickness
should be measured. (Courtesy of Windy City Ultrasound, Inc.)
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Abnormal Findings
Gallstones:
Bright oval to round hyperechoic structure(s) within the gallbladder,
often with a posterior shadow on ultrasound (Fig. 19.30).
Pericholecystic
fluid: An anechoic stripe that borders the outer gallbladder wall and
should be visualized in two views. This fluid is often but not
necessarily circumferential (Fig. 19.31).
Thickened
gallbladder wall: A gallbladder wall that measures 4 mm or more is
considered abnormal.
Sonographic
Murphy's sign: Tenderness of the gallbladder when compressed under direct
visualization with the ultrasound transducer.
Dilated
common bile duct (CBD): A CBD with an internal diameter greater than 4.0
mm is dilated; however, documented measurements up to 8.0 mm can be
normal in the elderly. One rule of thumb is that 4 mm up to age 40 and
thereafter an increase of 1 mm per decade represents the normal range.
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Gallbladder:
Gallstone The bright
oval-to-round hyperechoic structure within the gallbladder with a
posterior shadow is the classic gallstone presentation seen on
ultrasound. (Courtesy of Michael J. Lambert, MD, RDMS.)
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Gallbladder:
Pericholecystic Fluid A
circumferential anechoic stripe that borders the outer gallbladder
wall is consistent with pericholecystic fluid. A small gallstone with
posterior shadowing is also seen. (Courtesy of Windy City Ultrasound,
Inc.)
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Scan Pearls for Gallbladder
Ultrasound
1. It is frequently necessary
to have the patient take a deep breath and hold it to allow the
gallbladder to descend into sonographic view.
2. Measure the anterior wall
when evaluating wall thickness. The thickness of the posterior wall is
often affected by "posterior enhancement"; therefore it may
falsely appear thickened.
3. The duodenum is located
medially to the gallbladder. It may be interpreted as a gallstone even by
proficient sonographers if care is not taken to evaluate the gallbladder
completely and to observe for peristalsis on areas suspected to be bowel.
4. If you suspect gallstones
but do not visualize "shadowing," confirm that your focal point
is at the area of interest and try changing the transducer frequency if
possible (e.g., increase from 3.5 to 5.0 MHz).
5. If pericholecystic fluid is
suspected but difficult to determine, it may be helpful to increase the
frequency or convert to a linear transducer.
6. Most ultrasound systems
provide a cinematic loop, or "cineloop," that will allow the
sonographer to recall on average 20 to 40 images that occurred before the
image was frozen. Scrolling through these images is helpful in
identifying the cleanest and sharpest image of the CBD to measure.
7. The gallbladder tends to
migrate inferiorly in elderly patients, so that it may lie significantly
below the costal margin.
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Abdominal Aorta Ultrasound
Ultrasound of the abdominal aorta
is used to diagnose or exclude an abdominal aortic aneurysm (AAA). As the
general population ages, the diagnosis of AAA should occur with more
frequency, and the use of ultrasound of the abdominal aorta in the ED for
patients with abdominal, back, or flank pain should also increase.
Clinical Indications for
Abdominal Aorta Ultrasound
Abdominal,
back, or flank pain
Pulsatile
abdominal mass
Hypotensive
patient with abdominal pain or distention
Early diagnosis of AAA can
improve patient survival. When a patient is in shock, there is no bedside
test superior to an ESUE of the aorta to diagnose an AAA. Since aortic
aneurysms occur as both fusiform (most common) and saccular types, it is
essential that the ESUE of the aorta include both sagittal and transverse
components. It is generally accepted that an aortic measurement of
greater than 3.0 cm in diameter is abnormal, with a significant risk of
aortic rupture starting with measurements greater than 5.0 cm. This
section illustrates the abdominal vasculature, which will aid in
identification of the abdominal aorta and evaluation of AAAs.
Required Views for Abdominal
Aorta Ultrasound
Transverse
view
Sagittal
view
Recommended Transducers for
Abdominal Aorta Ultrasound
Convex
array
Microconvex
Phased
array
Mechanical
sector
Abdominal Aorta Window 1:
Transverse View
Technique
The
patient is supine.
Place
the transducer in the epigastrium with the transducer indicator oriented
to the patient's right. Move down the abdominal aorta to the bifurcation
(about the level of the umbilicus) (Fig. 19.32).
Identify
the liver, aorta, inferior vena cava (IVC), superior mesenteric artery
(SMA), splenic vein (SV), and "spinal stripe" at the level of
the proximal aorta (Fig. 19.33).
Identify
the IVC, aorta, and spinal stripe at the mid- and distal aorta.
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Abdominal
Aorta: Transverse View The
transducer is placed in the epigastrium with the transducer indicator
oriented to the patient's right; it is then moved down the abdominal
aorta to the bifurcation. (Courtesy of Windy City Ultrasound, Inc.)
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Abdominal
Aorta: Transverse View Various
structures are identified, including the liver, inferior vena cava
(IVC), superior mesenteric artery (SMA), splenic vein (SV), aorta,
and "spinal stripe." (Courtesy of Windy City Ultrasound,
Inc.)
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Abnormal Findings
AAA:
Anteroposterior measurements of more than 3.0 cm are suspicious for an
aneurysm (Fig. 19.34).
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Abdominal
Aorta: Aneurysm A large
abdominal aortic aneurysm (AAA) is seen in this view. (Courtesy of
Michael J. Lambert, MD, RDMS.)
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Abdominal Aorta Window 2:
Sagittal View
Technique
The
patient is supine.
Place
the transducer in the epigastrium with the transducer indicator oriented
toward the patient's head. Move down the abdominal aorta to the
bifurcation (about the region of the umbilicus) (Fig. 19.35).
Identify
the liver, aorta, inferior vena cava (IVC), celiac trunk, and superior
mesenteric artery (SMA) (Fig. 19.36).
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Abdominal
Aorta: Sagittal View The
transducer is placed in the epigastrium with the transducer indicator
oriented toward the patient's head; it is then moved down the
abdominal aorta to the bifurcation. (Courtesy of Windy City
Ultrasound, Inc.)
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Abdominal
Aorta: Sagittal View The
liver, aorta, celiac trunk, and superior mesenteric artery (SMA) are
identified in this view. (Courtesy of Windy City Ultrasound, Inc.)
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Abnormal Findings
AAA:
Anteroposterior measurements of more than 3.0 cm are suspicious for an
aneurysm.
Scan Pearls for Abdominal Aorta
Ultrasound
1. The ESUE of the abdominal
aorta should begin in the transverse view, since this view provides the
greatest amount of information and is essential for the diagnosis of a
saccular aneurysm.
2. Measure the entire diameter
of the aorta or aneurysm and not just the lumen or false lumen. Include
measurements of the proximal, mid-, and distal aorta.
3. If a significant amount of
bowel gas is present, sit the patient at 45 degrees and apply constant
gentle pressure.
4. The IVC will generally
collapse when you have the patient abruptly "sniff"—a
result of the negative pressure transmitted to the venous system by this
maneuver.
5. If pulsed Doppler is
available, it may be used to discriminate between the highly pulsatile
flow of the aorta and the low-amplitude rumble of the IVC.
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Renal Ultrasound
Renal ultrasound can yield
helpful diagnostic information for the patient presenting with abdominal
or flank pain consistent with renal colic. Obstructive uropathy due to
kidney stones is the principal pathology identified with renal
ultrasound. However, it is not standard practice for emergency physicians
to perform renal ultrasound to identify renal or ureteral calculi;
rather, the kidneys are evaluated for hydronephrosis. The presence of
hydronephrosis in the patient with renal colic is presumed to be a direct
result of ureteral obstruction. There is no accurate means of determining
the degree of obstruction by the presence of hydronephrosis.
Clinical Indications for Renal
Ultrasound
Flank
pain
Renal
colic
Abdominal
pain in the elderly
Hematuria
Costovertebral
angle (CVA) tenderness
The diagnostic dilemma for many
emergency physicians is how to effectively utilize the renal ESUE in the
patient with suspected renal colic. Although hydronephrosis is the
primary sonographic finding in renal ESUE, renal cysts, calculi, and
renal masses may also be identified.
The recommended sonographic
approach to the kidney is identical to that for the RUQ and LUQ windows
in the trauma/FAST examination previously discussed. The coronal view
allows the sonographer to visualize the right or left kidney from the
superior to inferior poles. The renal ESUE is best interpreted when
comparative images are obtained between the right and left kidneys. It is
important to realize that many approaches to the renal system, described
in other texts, may be useful at times; however, the coronal view is
familiar to the emergency physician. For that reason it is our primary
window for evaluating the kidneys on the renal ESUE.
Required Views for Renal
Ultrasound
Coronal
views (right and left)
Renal Ultrasound Window 1: Right
and Left Coronal Views
Recommended Transducers for
Renal Ultrasound
Convex
array
Microconvex
Phased
array
Mechanical
sector
Technique
The
patient is supine.
The
transducer indicator is oriented toward the patient's head.
The
transducer is directed as a coronal section through the body in the
midaxillary to posterior axillary lines (Fig. 19.37). Begin scanning
between the 9th to 11th ribs on the right and the 8th to 11th ribs on the
left.
Identify
the liver, right kidney, renal cortex (with pyramids), and central renal
sinus (Fig. 19.38).
Identify
the spleen, left kidney, renal cortex (with pyramids), and central renal
sinus (Fig. 19.39).
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Renal
Ultrasound: Coronal View The
transducer is directed in the midaxillary to posterior axillary lines
for scanning between the 9th to 11th ribs on the right and the 8th to
11th ribs on the left. (Courtesy of Windy City Ultrasound, Inc.)
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Renal
Ultrasound: Right Coronal View
The liver, right kidney, and diaphragm are seen in this view.
(Courtesy of Windy City Ultrasound, Inc.)
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Renal
Ultrasound: Left Coronal View
The spleen, left kidney, and diaphragm are seen in this view.
(Courtesy of Windy City Ultrasound, Inc.)
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Abnormal Findings
Hydronephrosis:
Dilatation of the renal sinus with dark black, anechoic fluid within the
bright renal sinus (Fig. 19.40).
Renal
calculi: Bright hyperechoic oval/round structures within the cortex or
renal sinus (posterior shadowing is often present).
Renal
cyst: Anechoic structure often at the periphery of the renal cortex with
a thin wall, and posterior acoustic enhancement.
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Renal
Ultrasound: Hydronephrosis
Dilatation of the renal sinus with dark black, anechoic fluid within
the bright renal sinus is consistent with hydronephrosis. (Courtesy
of Paul R. Sierzenski, MD, RDMS, FAAEM.)
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Scan Pearls for Renal Ultrasound
1. If your machine has
"dual" or "multi-image" modes, selecting this feature
will allow you to make an on-screen side-by-side comparison of both
kidneys.
2. Rib shadows will be evident
with this coronal view. Have the patient hold his or her breath in
inspiration and move the transducer a rib space higher or lower to
visualize the kidney from the superior to the inferior pole.
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Pelvic Ultrasound
Pelvic ultrasound is frequently
used to evaluate the patient presenting with pelvic pain and/or vaginal
bleeding, who may have a host of underlying clinical conditions. Among
these are ovarian cyst, tuboovarian abscess, ovarian torsion, fetal
demise, urinary retention, incomplete or threatened abortion, molar
pregnancy, appendicitis, urinary tract infection, ureteral calculi, or
pelvic inflammatory disease. However, the primary goal of the pelvic
emergency screening ultrasound examination (ESUE) is to exclude an
ectopic pregnancy. Pelvic ultrasound is accomplished with two different
scanning techniques: transabdominal and endovaginal.
Pregnant patients presenting with
abdominal pain or vaginal bleeding during the first trimester must have
an ectopic pregnancy excluded. This is commonly accomplished in the ED
setting by identifying an intrauterine pregnancy.
Clinical Indications for Pelvic
Ultrasound
Pelvic/abdominal
pain
Vaginal
bleeding (pregnant or nonpregnant patient)
Suspected
pregnancy
Scan Requirements for Pelvic
Ultrasound
1. Transabdominal ultrasound
(uses the bladder as an acoustic window): sagittal and transverse views
2. Endovaginal ultrasound
(provides a wider field of view, with better definition of anatomy):
sagittal and coronal views
Pelvic Transabdominal Sonography
(TAS) Window 1: Sagittal View
Recommended Transducers for
Pelvic TAS
Convex
array
Microconvex
Phased
array
Mechanical
sector
Technique
The
patient is supine.
Place
transducer superior to symphysis pubis, with the transducer indicator
directed toward the umbilicus (Fig. 19.41).
Identify
the bladder (triangular), uterus, rectum, ovaries, and the vesicouterine
and rectouterine pouches (pouch of Douglas) (Fig. 19.42).
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Pelvic
Transabdominal Ultrasound: Sagittal View The transducer is placed superior to symphysis
pubis, with the transducer indicator directed in a line through the
umbilicus (H = head, F = foot). (Courtesy of Windy City Ultrasound,
Inc.)
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Pelvic
Transabdominal Ultrasound: Sagittal View The bladder (triangular in this view) and
uterus are seen. The rectum, ovaries, and vesicouterine (V) and
rectouterine (pouch of Douglas) (D) pouches may be seen with movement
of the probe. (Courtesy of Windy City Ultrasound, Inc.)
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Abnormal Findings
Free
intraperitoneal fluid: Anechoic (dark) bands of fluid located in the
vesicouterine and/or rectouterine pouch.
Pelvic Transabdominal Sonography
(TAS) Window 2: Transverse View
Technique
The
patient is supine.
From the
TAS sagittal view, rotate the transducer 90 degrees counterclockwise or
place it superior to symphysis pubis, directed in a line connecting the
anterior superior iliac crests (gradually angle caudally) (Fig. 19.43).
Identify
the bladder (rectangular), uterus (if present), rectum, ovaries, and the
vesicouterine and rectouterine pouches (pouch of Douglas) (Fig. 19.44).
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Pelvic
Transabdominal Ultrasound: Transverse View The transducer is rotated 90 degrees counterclockwise
from the sagittal view and directed in a line connecting the anterior
superior iliac crests. The transducer is angled caudally to complete
the view. (Courtesy of Windy City Ultrasound, Inc.)
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Pelvic
Transabdominal Ultrasound: Transverse View The bladder (rectangular in this view),
uterus, and ovary are seen. The rectum and the vesicouterine and
rectouterine (pouch of Douglas) may be seen with movement of the
probe. (Courtesy of Windy City Ultrasound, Inc.)
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Abnormal Findings
Free
intraperitoneal fluid: Dark anechoic bands of fluid located in the
vesicouterine and/or rectouterine pouch.
Scan Pearls for Transabdominal
Ultrasound
1. A full bladder allows better
visualization of structures posterior to the bladder in transabdominal
ultrasound. An empty/minimally filled bladder is preferred for
endovaginal ultrasound.
2. A small amount of
free fluid found in the posterior cul-de-sac of the pelvis can be
physiologic.
Endovaginal Sonography (EVS)
Window 1: Sagittal View
Technique
The
patient is supine (lithotomy position).
With a
latex condom/shield covering the transducer, place it into the vagina,
directed toward the anterior fornix in a line through the umbilicus (Fig.
19.45).
The
transducer indicator is directed up.
Identify
the bladder (sliver), uterus, rectum, ovaries, and the vesicouterine
(anterior) and rectouterine (posterior) cul-de-sacs (Fig. 19.46).
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Endovaginal
Sonography: Sagittal View The
transducer is directed toward the anterior fornix in a line through
the umbilicus (A); it is then placed into the vagina (B).
The probe is advanced gradually. (Courtesy of Windy City Ultrasound,
Inc.)
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Endovaginal
Sonography: Sagittal View The
uterus with an endometrial stripe is seen in this view. Other structures
to be identified include the bladder, rectum, ovaries, and
vesicouterine and rectouterine pouches. (Courtesy of Windy City
Ultrasound, Inc.)
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Abnormal Findings
Free
intraperitoneal fluid: Anechoic (dark) bands of fluid located in the
vesicouterine and/or rectouterine pouch.
Ectopic
pregnancy: Extrauterine gestation may have an accompanying
"pseudosac" (an anechoic fluid collection within the
endometrial echo of the uterus) in the uterus (Fig. 19.47).
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Endovaginal
Sonography: Ectopic Pregnancy
An extrauterine gestation with an accompanying "pseudosac"
(an anechoic fluid collection without a clear double decidual
reaction) in the uterus is seen. (Courtesy of Michael J. Lambert, MD,
RDMS.)
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Endovaginal Sonography (EVS)
Window 2: Coronal View
Technique
The
patient is supine (ideally in the lithotomy position).
From the
EVS sagittal view, rotate the transducer counterclockwise 90 degrees or,
with a latex condom/shield covering the transducer, place the transducer
into the vagina directed toward the posterior fornix in a line through
the umbilicus (Fig. 19.48).
Identify
the bladder (sliver), uterus (ovoid) (Fig. 19.49), rectum, ovaries (Fig.
19.50), and the vesicouterine and rectouterine pouches (pouch of
Douglas).
Identify
an intrauterine pregnancy if present (Fig. 19.51).
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Endovaginal
Sonography: Coronal View From
the sagittal view, the transducer is rotated counterclockwise 90
degrees (A) and directed toward the posterior fornix in a line
through the umbilicus. (Courtesy of Windy City Ultrasound, Inc.)
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Endovaginal
Sonography: Coronal View The
oval-shaped uterus with a hyperechoic endometrial stripe is seen in
this view. Other structures to be identified include the bladder,
rectum, ovaries, and the vesicouterine and rectouterine pouches.
(Courtesy of Windy City Ultrasound, Inc.)
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Endovaginal
Sonography: Ovary An ovary
with a small cyst and a follicle are seen in this view. Color-flow
Doppler, if available, facilitates identification of vascular
structures. The iliac vein is seen in this view. (Courtesy of Michael
J. Lambert, MD, RDMS.)
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Endovaginal
Sonography: IUP An intrauterine
pregnancy of about 9 weeks' gestation is seen. (Courtesy of Michael
J. Lambert, MD, RDMS.)
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Abnormal or Positive Findings
Free
intraperitoneal fluid: Anechoic (dark) bands of fluid located in the
vesicouterine (anterior) or rectouterine (posterior) cul-de-sac.
Live
intrauterine pregnancy: Greater than 5-mm gestational sac with a thick,
concentric echogenic ring within the endometrial echo of the uterus and
both of the following: fetal pole with cardiac activity.
Intrauterine
pregnancy(IUP): Greater than 5-mm gestational sac with a thick,
concentric echogenic ring within the endometrial echo of the uterus and
one of the following: yolk sac, fetal pole, or double decidual sign (the
decidua capsularis and decidua vera seen as two distinct hypoechoic
layers surrounding the early gestational sac) (Fig. 19.52).
Abnormal
IUP: Gestational sac greater than 10 to 12 mm without yolk sac,
gestational sac greater than 16 mm without fetal pole, or definitive
fetal pole without cardiac pulsation.
No
definitive IUP: The uterus appears empty and no definitive ectopic
pregnancy is visualized. Possible diagnosis includes early IUP, abortion,
ectopic pregnancy.
Ectopic
pregnancy: Greater than 5-mm gestational sac and thick, concentric
echogenic ring outside the endometrial echo of the uterus and one
of the following: definitive yolk sac, obvious fetal pole, cardiac
activity.
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Intrauterine
Gestational Sac Discreet ring
of an intrauterine gestational sac seen on transvaginal ultrasound.
No yolk sac is visualized. A double decidual sac sign is seen,
however, lending evidence of a true gestational sac versus a
pseudogestational sac formed from a decidual cast in ectopic pregnancy.
A thorough look in the adnexa is important in diagnosing ectopic
pregnancy when a gestational sac is the only finding. (Courtesy of
Janice Underwood, RDMS.)
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Scan Pearls for Endovaginal
Ultrasound
1. On insertion of the
transducer, identify the bladder.
2. In the sagittal view,
identify the endometrial stripe from the fundus of the uterus to the
cervix. This is accomplished by tilting the probe (anteriorly to
posteriorly) while maintaining a sagittal plane of the uterus.
3. Return to the fundus of the
uterus in a sagittal view and slowly evaluate the right and then left
borders of the uterus in the longitudinal axis.
4. Turn the transducer
counterclockwise 90 degrees to enter the coronal plane. The uterus should
appear oval in this view. Scan posteriorly to the cervix and then
superiorly to the fundus of the uterus to exclude the presence of a
bicornuate uterus.
5. If a pregnancy or
intrauterine sac is identified, further evaluate with measurements and an
assessment of fetal cardiac activity.
6. To evaluate the ovaries,
begin with the patient's right ovary and scan initially in the
longitudinal (sagittal) plane, then rotate the transducer
counterclockwise 90 degrees and evaluate the ovary in the coronal plane.
The ovaries ideally will be located anteromedially to the external iliac
vessels. This is often only a guide to their location, and a methodical
approach is often required to visualize both ovaries.
7. If the uterus is difficult
to identify, withdraw the transducer slightly. A common error in EVS is
inserting the transducer too far, thus bypassing the uterus and imaging
only bowel.
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