Download Interpretive Approach and Reporting the Intensive

Chest X-Ray, Folio
Interpretive Approach and Reporting the Intensive Care Bedside Chest X-Ray
Les Folio, D.O., MPH, FAOCR
Radiology and Imaging Sciences, National Institutes of Health, Bethesda, MD
Introduction
Approach to the Bedside Chest X-Ray
The chest x-ray (CXR) remains one of the most
commonly requested imaging studies, yet is one of the
most complex and least understood, particularly the
intensive care unit (ICU) bedside examination. In
addition to deciphering numerous lines, tubes, lung
and pleural findings of the AP (anterior-posterior)
radiograph, critical care providers look to radiologists’
reports to summarize any pertinent changes in
underlying pathological processes. This article will
provide an overview of the bedside chest radiograph
in the ICU setting, as well as a guide to effective
reporting for the radiologist.
The recommended approach to CXR interpretation
is to first identify abnormal findings, including their
location and distribution, and then further define
patterns to help classify and categorize. This
represents the body of the report. Based upon this
information and correlation with any pertinent history,
radiologists generate a differential diagnosis, or
conclusion; that is, the impression section of the
report.
While computed tomography (CT) has added
tremendous value in chest imaging in ICU patients, the
CXR remains the mainstay in ICU imaging. Compared
to CT scans, the CXR can be obtained more readily and
is associated with less radiation; thus, CXRs can be
performed serially for temporal comparison.
Ultrasound is becoming more commonplace and can
often be complementary to CXR, CT, and physiologic
parameters.1
This article presents an overview of common CXR
findings in the ICU setting with example reporting, in
the hope of increasing awareness of accepted report
terminology. It will also touch on traditional views,
new techniques/approaches to bedside chest imaging,
and technological advances that may improve
diagnostic accuracy on CXR and negate the need for CT
in some conditions.2
Topic points include positions of lines and tubes,
abnormal collections of fluid and air, and common
causes of pulmonary opacities. Radiologists should
keep in mind that ICU physicians want to know
findings that may alter management, those which are
potentially life-threatening, as well as pertinent
temporal changes.
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For example, the report body and impression of a
CXR describing a consolidation in a patient with cough,
fever, and elevated white blood cell count may look
like this:
Findings: A focal patchy opacity is noted in the
right upper lung field with air-bronchograms.
Impression: Consolidation on right, consistent with
pneumonia
It is important to have a systematic approach to CXR
interpretation, especially when reviewing complex
studies, such as the case shown in Fig. 1. One method
uses a mnemonic-based search pattern consisting of
the ABCDEs twice. The acronym includes the following:
Airway (including an endotracheal [ET] tube, when
applicable), Aorta (contours, edges, central lines),
Breathing (lungs and pleura), Bones (quick review
since this often does not significantly change in the
ICU), Circulation (pulmonary vessels), Cardiac
(silhouette), Diaphragm (free air, costophrenic angles),
Deformity (post-operative, positioning considerations),
Soft tissues (chest wall), Shoulders (periphery of
projection). Other search patterns include starting in
the midline and working one’s way outward or vice
versa. The key point is to have a systematic search
pattern which includes all aspects of the CXR and
ensuring that the pattern is followed on each and
every examination. This will help avoid becoming
overwhelmed, especially when there are a multitude
of findings.
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
Chest X-Ray, Folio
Figure 1. Example of a Potentially Perplexing Case Simplified Through a
Systematic Approach and Routine Reporting.
Starting with the ET tube, the tip is easily seen at the inferior medial clavicles
within 5cm from the carina. Although the NG tube tip is not seen, the sideport
is within the stomach; therefore, there is no need to say the tip is not seen.
Next, describe the chest tubes and the Swan-Ganz catheter with its tip in right
PA. Then move on to the tube effects, such as the subcutaneous emphysema,
surgical clips, and extracardiac lucency. In evaluating the hemithoracies, the
diaphragmatic silhouette is obscured, especially on the left due to a pleural
effusion. Pulmonary opacities within the left hemithorax result from a pleural
effusion with underlying parenchymal consolidation versus atelectasis. The
cardiac silhouette and aortic contour are enlarged and show lucency on the
left representing a pneumomediastinum. Finally, evaluate the extrathoracic
regions of the film, including the upper abdomen, soft tissues, and bony
structures.
Figure 2.
Incorrect Positioning of an
Endotracheal Tube.
A CT scout image (A) shows
an ET tube located within the
left mainstem bronchus.
Portable chest radiograph
following repositioning of the
ET tube (B) demonstrates
correct positioning within the
trachea with residual right
lower lobe atelectasis from
prior malpositioning; the
region of atelectasis resolved
on subsequent films (not
shown).
A
Reports should be predictable and consistent for
critical care providers to quickly understand the
meaning; for example, some radiologists report on
lines and tubes first in the body, keeping that order in
the impression. This allows ICU staff and other
providers to know where to look for specific
information in reports. Standard reporting terminology
and formats for chest CT have been proposed, and the
Radiologic Society of North America (RSNA) has
existing and developing report templates in a variety
of formats.3 The RadLex initiative, implemented by
RSNA, has led to standardized terms and reporting that
may be useful in thoracic imaging.4,5 One group of
researchers developed a structured report for the
chest x-ray with standardized terminology.6 Although
there is no national or international standard, there
seems to be a trend in this direction.
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
B
Support Devices: Lines and tubes
The ICU generates many requests for support device
placement on CXR, especially serial examinations in
patients with multiple lines and tubes. The American
College of Radiology (ACR) appropriateness criteria
provides guidelines for imaging in the setting of line
and tube placement.7 The literature supports
obtaining a CXR immediately following placement of
endotracheal, enteric (especially feeding tubes), and
chest tubes; however, it does not support daily CXRs in
the absence of a change in clinical condition or
suspected line or tube migration.8-10
A comprehensive review of lines and tubes is
beyond the scope of this article. However, it is
important to know which types of lines and tubes have
been placed, along with their optimal locations and
potential complications of malpositioning. Figs. 2, 3,
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Chest X-Ray, Folio
Figure 3. Malpositioning of Central Venous
Catheters.
Portable chest radiograph flowing placement of
a right jugular central line (A) shows an
abnormal cephalad course of the catheter
extending into the neck. Portable chest
radiograph following placement of a left
subclavian central line in a different patient (B)
reveals the catheter coursing into a variant left
superior vena cava.
A
B
examinations when technologists have different
degrees of inclination and thresholds for placing the
“Upright,” “Erect,” or “Semierect” markers on the
cassette. Rotation is often accentuated in bedside
imaging compared to standard PA projections
performed in the Radiology Department, making
changes on serial exams more difficult to assess.
Overlying material, such as the external component of
tubes and lines, also limit visualization and evaluation
of underlying structures.
Figure 4. Positioning of Multiple Central Lines.
Frontal chest radiograph reveals placement of bilateral
peripherally-inserted central venous catheters (PICC lines),
as well as a right internal jugular (IJ) central venous catheter
(CVC). The tip of the right IJ CVC is optimally located within
the distal superior vena cava. The left PICC line tip projects
over the right atrium (arrows).
and 4 demonstrate examples of correct and incorrect
positioning of endotracheal tubes and central venous
catheters. Chest tube positioning is discussed in the
section covering pathology of the pleural space.
Positioning, Technique Ideas and Technical
Advances
The portable CXR is often inconsistent and
sometimes limited due to variable patient positioning
(rotation, tilt, angle of inclination, etc.). For example, it
can be difficult to evaluate pleural effusions on serial
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New technologies to improve CXR interpretation are
available or in design and include dual energy,
temporal subtraction, tomosynthesis, and decision
support.11 Also available is line and tube visualization
software, which improves conspicuity of various
support devices (Fig. 5).12,13 Some centers are using
portable CT in the ICU, which has been found to be
advantageous due to minimizing the need for patient
transport (especially with many support devices) and
obtaining more rapid assessments with superior
spatial resolution.14
Pleural Fluid, Air, and Loculations
Pleural effusions are common in ICU patients. It is
important to distinguish effusions from other
pathologic processes, as well as to assess for changes
over time on serial examinations. Since fluid is
dependent when not loculated or otherwise bound,
optimal positioning in as upright a position as possible
is paramount. Inconsistent positioning over time often
gives false impressions of changes in severity and has
variable effects on masking of underlying conditions,
such as pneumonia or atelectasis. Technologists will
often indicate patient positioning with use of arrows or
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
Chest X-Ray, Folio
Figure 5.
Application of the Line and
Tube Visualization Software.
In
this
patient
who
underwent right forequarter
amputation from a scapular
sarcoma, standard (A) and
post-processed (B) CXR
images were obtained. The
post-processed image (B)
more readily identifies the
malpositioned left PICC line
within
the
right
brachiocephalic vein. There
B
A
are
also
postoperative
features to the lungs bilaterally with resultant volume loss to left lower lung field. Note a prototype inclination marker in the upper left
portion of the image with demonstrates an inclination angle of 60 degrees.
markers stating “Upright;” however, there is poor
agreement or consistency as to when to use such
indications. For example, defining a threshold angle of
60 degrees before an examination is to be considered
“Upright.” The angle of inclination also affects
evaluation for pneumothoraces or free intraabdominal air.
The use of decubitus projections can be extremely
valuable in assessing the mobility and possibly the
drainability of pleural fluid, often negating the need
for CT (Fig. 6). One should keep in mind, however, that
with the many support devices and critical nature of
the patient’s underlying medical condition, decubitus
positioning in the ICU is often difficult and in some
cases not possible. The decubitus view to order is the
A
B
side of the effusion or what technologists often refer
to as “side down, side seen.” This means that a rightsided effusion should be evaluated with a right side
down decubitus projection. This is opposite of the
abdominal decubitus projection when looking for freeair (“side up, side seen”) where a left lateral decubitus
projection detects free air at the liver margin.
Although this appears intuitive, it is important to be
clear with the terminology when recommending,
ordering, performing, or interpreting decubitus
examinations.
Empyemas represent localized infectious collections
within the pleural space and are not uncommon in the
ICU setting. Differentiation from simple pleural
effusions is a common and important question of ICU
C
Figure 6. How the Decubitus Projection Can Determine Mobility of Pleural Effusions. Frontal (A) and lateral (B) chest radiographs
demonstrate a moderate-sized right pleural effusion with suspected peripheral loculations. The right-side down decubitus view (C) verifies
free mobility of the pleural fluid without evidence of loculations, thus negating the need for a CT examination.
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
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Chest X-Ray, Folio
Figure 7. Empyemas.
Frontal chest radiograph (A) reveals
peripheral opacities along the lateral
margins of the thoracic cavities, some
of which have irregular borders. The
size and extent of the collections were
resulting in cardiac tamponade.
Coronal reformatted CT image (B)
better depicts the loculated collections
which were subsequently drained but
recurred.
A
B
Figure 8. Lung Abscess.
Frontal (A) and lateral (B) chest
radiographs show a lung cavity with
air-fluid level in the superior
segment of the right lower lobe
(right upper lung field) that has the
same size and configuration on both
the PA and lateral views, confirming
a spherical shape. Biopsy revealed
an aspergilloma in this patient with
Job’s syndrome.
A
B
staff. However, the distinction cannot be made on CXR
alone. Common findings include loculated, non-mobile
collections of pleural fluid (Fig. 7). A relatively specific
finding for empyemas includes air-fluid levels that are
disparate in size/length when comparing the frontal
and lateral projections.15 This supports a non-spherical
shape and is helpful in distinguishing empyemas from
simple effusions or pulmonary abscesses.16
Most parenchymal abscesses or cavities are
spherical in shape, resulting in air-fluid levels of similar
size/length on all projections (Fig. 8). Although there
are findings suggestive of empyemas on CXR,
recommending a CT and potentially image-guided
drainage is often in order.
Visualization of air-fluid levels in the pleural space is
a useful finding in the setting of subtle
pneumothoraces (Fig. 9). A dependent fluid level in the
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lower lung field often indicates the presence of a
hydropneumothorax. Treatment of pneumothoraces
often depends upon the size and pneumothorax and
clinical status of the patient. Often times, placement of
a chest tube is necessary.
Chest tubes can be malpositioned in a manner
where bedside radiography alone is not adequate for
evaluation.17 In this setting, CT is often necessary to
evaluate for a malpositioned tube, typically when an
abnormal course is identified on CXR or the tube is not
draining properly. Common findings associated with
malpositioning include visualization of the tube within
a pulmonary fissure (Fig. 10) or in a superficial location
with the sideports outside of the chest cavity.
Placement within the pulmonary parenchyma or the
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
Chest X-Ray, Folio
Figure 9.
Air-fluid Level in the Pleural Space
Indicative of a Hydropneumothorax.
Frontal chest radiograph (A) demonstrates
an air-fluid level within the inferior right
hemithorax (thick arrows). Magnified view
of the right upper thoracic cavity (B)
reveals a subtle pneumothorax (thin
arrows).
A
A
B
Figure 10.
Malpositioned Chest Tube.
Frontal chest radiograph (A)
shows bilateral chest tubes
with
persistent
pneumothoraces. The chest
tube on the right was not
draining
properly.
Para
coronal/axial (B) and sagittal
reformatted (C) CT images
demonstrate an interfissural
course of the right-sided
chest tube.
A
B
C
Figure 11.
Pneumonia.
Frontal chest radiograph
(A) demonstrates a focal
rounded
consolidation,
likely within the lateral
right middle lobe due to
the lack of obscuration of
the diaphragmatic border.
Coronal reformatted (B)
and axial (C) CT images
confirm the middle lobe location and best depict the central air bronchograms in this patient with fever and X-linked agammaglobulinemia
(XLA), which is the underlying cause of the lower lobe bronchiectasis noted on the CT examination.
chest wall is less common.
Pulmonary/Lung Opacities
Pulmonary opacities are commonly seen in the ICU
setting. Distinguishing between air space disease and
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
atelectasis, especially on hypoinflated portable CXR, is
a common dilemma for radiologists. When air space
opacities are identified, differential conditions include
pneumonia, pulmonary edema, acute respiratory
distress
syndrome
(ARDS),
and
pulmonary
hemorrhage.
Atelectasis often mimics air space disease on CXR,
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Chest X-Ray, Folio
since it often presents as a focal opacity with or
without air bronchograms. A key distinguishing feature
is volume loss within the affected lobe, which may be
subtle but is a useful discriminator.
The imaging pattern of infectious pneumonia is
dependent upon the causative agent. Bacterial
infections present with lobar air space disease, which
may be localized or multi-focal (Fig. 11).
Parapneumonic effusions or empyemas may be seen.
Atypical infections, such as viral or Mycoplasma, tend
to be interstitial but may occasionally be lobar as well.
Nosocomial infections are more diffuse and aggressive
with a higher prevalence in patients who are
immunosuppressed. Cavitation is common and the
morbidity and mortality is significantly higher than
community-acquired pneumonia.
Left-sided congestive heart failure demonstrates a
predictable sequence of findings on CXR (Fig. 12).
Initially, there is enlargement of the cardiac silhouette
with cephalization of pulmonary blood flow. As the
degree of heart failure progresses, interstitial edema is
noted with prominent interstitial markings along the
periphery of the lung fields (Kerley B lines). Finally,
edema extends into the pulmonary parenchyma and
pleural space, resulting in air space opacities and
pleural effusions.
Acute respiratory distress syndrome (ARDS) often
occurs in the setting of shock or inhalation toxicity and
results in fluid accumulation within the lung
parenchyma. The air space disease may appear similar
to that of pulmonary edema; however, it is not
typically associated with cardiomegaly or pleural
effusions. The air space disease also tends to occur
along the lung periphery.18 Chronically, ARDS may
result in pulmonary fibrosis.
Pulmonary hemorrhage may be focal, especially in
the setting of trauma, or diffuse secondary to an
underlying systemic or autoimmune disease process.
Chest x-rays demonstrate multifocal air space
opacities, which may be ground glass, consolidated,
well-defined, or diffuse (Fig. 13). Cavitation is not
uncommon.19
Reporting/Terminology
Findings in the body of the report should support
the conclusions in the impression. A finding that
includes consolidation, for example, should have an
impression which includes a portion of the well-known
Figure 12.
A
B
C
D
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Congestive Heart Failure/Pulmonary Edema.
Sequential frontal chest radiographs in a patient
with progressive heart failure (A, B, and C) show an
initial normal examination (A) with subsequent
development of cardiomegaly, cephalization of
pulmonary vasculature, and increased peripheral
interstitial markings – referred to as Kerley B lines
(B). Air space disease and pleural effusions are
common and best depicted on images B and C. The
relative increased lung volumes on image C are the
result of interval intubation; enteric tubes and a
right IJ CVC were also placed in this patient (C) and
are appropriately positioned. A coronal reformatted
image (D) nicely shows the peripheral Kerley lines,
as well air space disease within the right lower lobe.
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
Chest X-Ray, Folio
Figure 13.
Diffuse Alveolar
Hemorrhage.
Frontal
chest
radiograph in a patient with known
Kaposi Sarcoma involving the lungs
(A)
demonstrates
multifocal
interstitial and air space pulmonary
opacities, as well as a left-sided
pneumothorax. As the patient’s
condition continued to deteriorate,
subsequent imaging (B) shows
extensive,
diffuse
pulmonary
opacification. The support lines
and tubes are appropriately
positioned.
Autopsy
revealed
diffuse alveolar hemorrhage.
Figure 14. Unsuspected Finding on CXR.
A frontal radiograph of the chest and abdomen for line
and tube placement (A) reveals an unusual bowel gas
pattern compatible with pneumotosis intestinalis,
which was confirmed on CT (B). The right-sided PICC
line is in the SVC; the feeding tube tip is not seen,
however, it courses well into the duodenum.
differential diagnosis of water, pus, blood, protein, and
cells based upon the clinical history. If there is a new
finding of a focal opacity and the critical care team is
looking for infection, then pneumonia is most likely. If
the opacity is diffuse, then fluid or blood (DAH) may be
added to the list of differentials.
There are unique considerations in CXR terminology
with regards to 2-dimensional representation of 3dimensional structures. For example, there is
considerable overlap and variability of lung lobes;
hence the use of the term lung “fields,” which is
commonly used and appropriate. Also, if a central line
tip appears low in the superior vena cava (SVC),
positioning and projection could mean that the tip is
actually in right atrium; therefore, the broader phrase
“overlying the cavoatrial junction” may be useful.
ICU staff, like radiologists, are busy and want
concise information at their fingertips. The radiologist
should avoid extraneous information and be
J Am Osteopath Coll Radiol 2014; Vol. 3, Issue 2
consistent and predictable. If the tip of the enteric
tube is not seen but the sideport is visible, state the
location of the sideport; there is no need to state that
the tip is not seen in such cases.
Although residents and fellows are often taught not
to use the term “infiltrate,” it may provide flexibility
for both the radiologist and the ordering provider. For
example, if one commits to “consolidation” or “fluid,”
this may minimize options for the clinician. Keeping
the differential (impression) broader allows providers
to apply the clinical information to their management.
However, there is a fine line between keeping
differentials broad and being noncommittal or
“hedging.”
Having an organized search pattern is essential in
evaluating the entire film. It also helps prevent
“satisfaction of search” where obvious abnormalities
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Chest X-Ray, Folio
are noted initially and more subtle findings are
overlooked.20 Fig. 14 shows an unsuspected case of
pneumotosis intestinalis picked-up on a CXR for line
and tube placement.
Interaction With Intensive Care Team; The
Report is Just the Beginning; ICU Rounds, Process
1.
2.
3.
4.
Although the radiology report represents the final
product of a particular diagnostic imaging study, it may
also represent the beginning of a diagnostic and
procedural dialogue with ordering providers. A
continuous feedback and understanding of clinicians’
needs provides insight that is otherwise not gained if
radiologists remain in isolation. Breaking the
misguided and stereotypical perceptions of
radiologists keeping to themselves in a dark room will
improve communication chains with ordering
providers and help guide the work-up and care for the
most critically-ill patients.
Summary
The chest x-ray remains one of the most common,
important, and complex examinations in the ICU
setting. Given the multitude of pathologies and
support devices often encountered, it is critical that
radiologists develop and follow a logical search pattern
to help define the underlying abnormalities, evaluate
all aspects of the film, and avoid “satisfaction of
search.” Correlating findings with the patient’s clinical
status will aid in providing a useful list of differentials.
Most importantly, continuous communication with
ordering providers will allow radiologists to help guide
The views expressed in this material are those
of the author, and do not reflect the official
policy or position of the U.S. Government or
NIH.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
the work-up and management of the most critically-ill
patients.
18.
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