## Thyroid Imaging Reporting and Data System (TI-RADS): A User’s Guide[1]
Franklin N. Tessler, MD, CM
William D. Middleton, MD
Edward G. Grant, MD
#### An earlier incorrect version of this article appeared online and in print. This article was corrected on April 2, 2018.
In 2017, the Thyroid Imaging Reporting and Data System
(TI-RADS) Committee of the American College of Radiology (ACR) published a white paper that presented a
new risk-stratification system for classifying thyroid nodules on the basis of their appearance at ultrasonography
(US). In ACR TI-RADS, points in five feature categories
are summed to determine a risk level from TR1 to TR5.
Recommendations for biopsy or US follow-up are based
on the nodule’s ACR TI-RADS level and its maximum diameter. The purpose of this article is to offer practical
guidance on how to implement and apply ACR TI-RADS
based on the authors’ experience with the system.
q RSNA, 2018
1 From the Department of Radiology, University of Alabama
at Birmingham, 619 S 19th St, JT N450, Birmingham, AL
35249 (F.N.T.); Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (W.D.M.);
and Department of Radiology, Keck School of Medicine,
University of Southern California, Los Angeles, Calif (E.G.G.).
Received May 31, 2017; revision requested July 10;
revision received July 22; accepted August 15; final version
accepted August 23. Address correspondence to F.N.T.
(e-mail: f tessler@uabmc.edu).
q RSNA 2018
-----
adiologists who interpret thyroid
ultrasonography (US) images frequently face the dilemma of how
# R
to report nodules, which are extremely
common and overwhelmingly benign
(1). Like risk-stratification systems
from other professional societies and
investigators, the American College of
Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS)
aims to provide an easy-to-apply
method for practitioners to determine
management (2). We believe that this
will improve consistency across practices and institutions and will benefit
patients by applying guidelines that are
based on evidence and consensus expert opinion.
ACR TI-RADS is founded on the
evaluation of US features in five categories—composition, echogenicity,
shape, margin, and echogenic foci—in
which each feature is assigned 0–3
points (Fig 1). Features in the first four
categories each have a single score derived from mutually exclusive choices,
whereas more than one feature may be
present in the echogenic foci category.
The nodule’s point total determines
its risk level, which ranges from TR1
(benign) to TR5 (highly suspicious).
In conjunction with the nodule’s maximum diameter, the TR level determines
whether to recommend a fine-needle
aspiration (FNA) biopsy, a follow-up
US examination, or no further action.
As with guidelines from professional
groups such as the American Thyroid
Association and the Korean Society of
Thyroid Radiology, the threshold size
for recommending FNA decreases as
the US features become more malignant
ACR TI-RADS recommends formally reporting up to four thyroid nodules with
the highest point totals. Because sonographers perform most US studies in radiology practices in the United States,
they are often the first ones to encounter nodules. Because it is often impractical for sonographers to obtain images
of and measure every nodule, they must
become familiar with the criteria that
determine which ones warrant further
attention from the interpreting radiologist. Before the implementation of ACR
TI-RADS, we recommend that sonographers receive in-service training that
covers feature assignments and measurement techniques. It also may be
helpful to post the ACR TI-RADS chart
in the scanning rooms, especially while
sonographers are becoming familiar
with the five feature categories.
For the patient’s initial US study, we
recommend that the sonographer take
a minute or two to obtain an overview
f th ti l d t l k f d l
appearing (3,4). Because the threshold
diameters for mildly and moderately
suspicious nodules (TR3 and TR4) are
larger than in other systems, adherence
to ACR TI-RADS will result in fewer
biopsies of benign nodules. Inevitably,
however, it will also result in fewer biopsies of malignant nodules, which is
why ACR TI-RADS recommends follow-up for some nodules that do not
meet the size criteria for FNA.
Feature assignment and measure
ment are both subject to inevitable interobserver variation. Scanning protocols
also come into play, as nodules must be
captured and labeled on static images
and/or real-time clips to be classified.
Finally, the reporting process must be
efficient and account for circumstances
such as patient or referring physician
preferences, previous biopsies, interval growth, and lymphadenopathy. The
purpose of this article is to present our
perspective on these issues and to provide practical advice to US practitioners
who adopt ACR TI-RADS. The opinions
expressed are ours and do not reflect or
imply endorsement by the ACR.
Scanning Protocol and Labeling
that might require further attention before capturing any images. He or she
should then proceed to scan the entire
gland following the sequence specified
in the laboratory’s protocol. In this
step, the sonographer should measure
up to approximately four nodules that
are likely to be reported as requiring
biopsy or follow-up based on ACR TIRADS, as well as obtain sufficient images to document the architecture of
the nodules.
As with all sonograms, depth, gain,
zoom, focal zone, frequency, pre- and
postprocessing, dynamic range, frame
averaging, compounding, and other
parameters should be optimized. We
have also found that real-time clips
are very helpful to highlight certain
features, notably comet-tail artifacts,
which may become more or less conspicuous as the scanning plane traverses the nodule. Nodules of interest
may be numbered sequentially, but if
the sonographer identifies more than
four, their numbering scheme may
conflict with the one that the radiologist reports subsequently. Therefore,
if this is the patient’s first US study,
we recommend that the sonographer
just label each nodule with its location
in the gland (Fig 2). In practices that
use worksheets, the sonographer may
indicate the location of nodules diagrammatically to make it easier for the
interpreting physician.
If the sonogram is being performed
for follow-up, whenever possible, the
sonographer should review prior images and reports to determine if any
nodules were described and measured.
Not every such nodule will require
Essentials
n Reports need only provide struc-n
tured descriptions of up to four
nodules that warrant further
attention.
n An initial overview scan facili-n
tates selection of nodules for further attention.
n The position and shape of the n
solid component of mixed cystic
and solid nodules may influence
management
**https://doi.org/10.1148/radiol.2017171240**
**Content codes:**
**Radiology 2018;** 287:29–36
**Abbreviations:**
ACR = American College of Radiology
FNA = fine-needle aspiration
PEF = punctate echogenic foci
TI-RADS = Thyroid Imaging Reporting and Data System
Conflicts of interest are listed at the end of this article.
S l th ti l b H t l i thi i
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Figure 1
Figure 1: Sonographic features and associated points grouped according to the five American College of Radiology Thyroid Imaging Reporting and Data System, or
TI-RADS, categories.
Figure 2
Figure 3
Figure 2: Transverse sonogram of a nodule in
a 61-year-old woman. The annotation shows the
nodule’s location in the left isthmus.
formal reassessment on the current
scan, but it is helpful to know where
to look before reimaging. Additionally,
if the previous sonogram was reported
by using ACR TI-RADS, nodules should
be numbered as they were in previous
reports. To maintain consistency, this
applies even if a previously reported
nodule is no longer present. For example, if one of four nodules has resolved,
the fourth nodule should still be denoted as number 4 on the images and in
the report.
nodule’s volume should be occupied
by tiny cysts (Fig 3) (5). It should be
possible to make this determination by
observation; if the cystic components
comprise less than 50%, the nodule
should not be treated as spongiform.
Additionally, the presence of other
features such as peripheral calcifications or macrocalcifications, which are
usually easy to recognize, means that
a nodule should not be classified as
spongiform. However, the small echogenic foci that represent the back walls
of minute cysts should not be misinterpreted as echogenic foci. Nodules with
shadowing calcifications that preclude
assessment of their architecture are
assumed to be solid and therefore receive 2 points for composition.
Distinguishing solid nodules from
mixed cystic and solid nodules may be
difficult in practice, as they represent
a continuum. Unlike with spongiform
nodules, ACR TI-RADS does not require that the observer estimate the
percentage of a nodule that is solid, as
this determination is often highly subjective and is less important than the
characteristics of the solid component.
This represents a departure from the
lexicon, which explicitly describes predominately cystic and predominately
solid nodules (5). As a general principle, however, otherwise-solid nodules
that contain small cystic components
that occupy no more than approximately 5% of the overall volume should
be classified as solid (Fig 4).
For nodules that contain more
th i i l lid t d
Feature Assignment: Improving
Accuracy and Consistency
As noted previously, five feature categories form the cornerstone of ACR
TI-RADS, and so it is critical to be as
objective as possible in applying them.
Some features are more straightforward
than others—for example, it is usually
not difficult to decide whether a nod
l i h h i h h i b t
Figure 3: Spongiform 0.9-cm nodule in a
59-year-old woman. More than 50% of the nodule
is composed of small cystic spaces. The nodule
received 0 points for composition because of its
spongiform designation and no additional points in
other categories ( TR1).
differentiating hypoechoic from markedly hypoechoic nodules may be more
challenging. In this section, we offer
guidance for the most problematic features in each category. Readers may
consult the ACR TI-RADS reporting lexicon white paper, which contains images
illustrating many of these features (5).
Composition
In ACR TI-RADS, nodules classified as
spongiform are not subject to further
feature assignment and are treated
as benign, with no further follow-up
needed. Most investigators agree that
spongiform refers to the presence of
very small cysts that are akin to the
fluid-filled spaces in a wet sponge, but
there is some controversy as to how
much of the nodule must have this appearance to qualify (6,7). Per the ACR
th id l i t l t 50% f th
-----
Figure 4
Figure 5
Figure 6
Figure 4: Sagittal sonogram of a 4.6-cm benign
colloid nodule in a 65-year-old woman. It was
classified as solid (composition score of 2), although
small cystic components were present. With 1
more point for isoechogenicity and none in other
categories, its point total was 3 ( TR3).
Figure 6: Benign mixed cystic and solid nodule
(1 point) in a 40-year-old woman. The 1-point
isoechoic solid component is distributed around the
periphery. The nodule received 2 points ( TR2).
shows that the solid material represents viable tissue rather than blood
clot, debris, or necrotic tissue.
Echogenicity
Assigning echogenicity by using the
adjacent thyroid parenchyma as a
frame of reference is usually straightforward. However, relative reflectivity may vary considerably depending
on scanning parameters, particularly
gain, transmit frequency, compression, and pre- and postprocessing.
When in doubt, we find it helpful
to consider echogenicity in multiple
planes of section. Real-time clips are
valuable in problematic nodule assessments. Because hyperechoic and
isoechoic nodules both receive 1 point
in ACR TI-RADS, distinguishing them
is not crucial. However, it is important to differentiate hypoechoic from
markedly hypoechoic nodules, as the
latter feature receives 1 additional
point in this category. Nodules that
are definitively less reflective than the
anterior neck muscles, which should
be visible on every image, are classified as markedly hypoechoic (Fig 7).
Here, too, scanning parameters play
a critical role, so it may be useful to
obtain images at various gain settings.
This maneuver may also facilitate
identification of completely anechoic
cysts that otherwise mimic markedly
hypoechoic nodules. Conversely, the
presence of flow within a uniformly
hypoechoic nodule confidently charac-i
Figure 7
Figure 7: Transverse sonogram shows 2.0-cm
markedly hypoechoic papillary carcinoma (arrows) in
a 24-year-old woman. The nodule received 2 points
for solid composition and 3 for marked hypoechogenicity, totaling 5 points ( TR4).
are therefore categorized as mixed
cystic and solid, the appearance of
the solid component helps determine
management. For example, the presence of punctate echogenic foci (PEF)
or macro- or peripheral calcifications
increases the nodule’s suspicion level
(8,9). These and other suspicious features that also apply to uniformly solid
nodules contribute to the point score
of mixed cystic and solid nodules. In
addition, the nodule’s maximum dimension, not the size of its solid component, governs recommendations. If
the solid component is smaller than
the size threshold for a completely
solid nodule at a given TR level but the
overall nodule is above the cutoff, FNA
Figure 5: Mixed cystic and solid papillary cancer
in a 39-year-old man has a lobulated solid mural
component with punctate echogenic foci (PEF). The
nodule received 1 point for composition, 1 for its
isoechoic solid component, and 3 for PEF, for a total
of 5 ( TR4).
with suspicious solid tissue that are
too small to warrant FNA will still usually require US follow-up, lessening the
likelihood that clinically important malignancy will remain undetected in the
long term.
Other characteristics of the solid
components, including their position
and shape, should also be considered.
Position refers to the location and
symmetry of the solid material relative to the whole nodule. Mural nodules that are isolated, masslike, and
protrude into the fluid are more suspicious. Shape refers to the interface
between the solid component and adjacent fluid. As with solid nodules, lobulation is a suspicious finding (Fig 5).
Conversely, solid material that is relatively smooth and more-or-less evenly
distributed around the periphery of a
nodule is less concerning (Fig 6). Some
authors have also called attention to
the interface between solid mural components and the cyst wall, with acute
angles being more worrisome (10,11).
Position and shape do not contribute to
the nodule’s point total, but if the solid
component exhibits any of these suspicious features, we occasionally recommend FNA even if the nodule does not
otherwise meet criteria for biopsy. The
presence of flow at color or power Doppler imaging does not reliably indicate
that the solid component is malignant,
nor does its absence mean that it is be
-----
Figure 8
Figure 9
Figure 8: Transverse sonogram of a taller-thanwide papillary cancer in a 47-year-old man. In
addition to 3 points for shape, the nodule warranted 2 points for solid composition, 1 point for
isoechogenicity, and 3 points for numerous punctate
echogenic foci, for a total of 9 points ( TR5).
Figure 9: Transverse sonogram in a 52-year-old
woman shows a benign follicular nodule with a
smooth margin (arrows). The nodule was assigned 2
points for solid composition and 1 for isoechogenicity,
for a total of 3 points ( TR3).
therefore suspicious (12). We also note
that nodules that are perfectly round
in cross section are technically neither
wider-than-tall nor taller-than-wide.
When that occurs, it is acceptable to
report the nodule as either wider-thantall or not taller-than-wide. Rarely, it
may be appropriate to assess this characteristic on a sagittal image if a nodule
is obliquely oriented in that plane, as it
may be round in cross section.
Margin
A nodule’s margin, defined as the character of its interface with adjacent intraor extrathyroidal tissue, is best appreciated along its anterior border, which
is orthogonal to the ultrasound beam.
This is facilitated by scanning with the
depth adjusted to show the part of the
nodule closest to the transducer. A
smooth margin is characterized by an
even, gradually curving interface (Fig 9).
If lobulation, angulation, or intrusion of
the nodule’s solid component into the
surrounding tissue is present to any
extent, the margin should be classified
as lobulated or irregular; both warrant
2 points, so it is not important to distinguish them (Fig 10). Extrathyroidal
extension is a 3-point feature that is
characterized by clear-cut invasion of
adjacent structures. This appearance,
which is pathognomonic for malignancy, should not be recorded merely
because a nodule bulges the border of
the thyroid gland (Fig 11). US clips may
be helpful to demonstrate that a nodule
truly invades the soft tissues, as they
will be fixed as the transducer moves.
If the nodule’s border is not depicted
clearly, it is categorized as ill defined
and receives 0 points for margin, as this
is not a discriminatory feature.
Echogenic Foci
Macrocalcifications and peripheral calcifications rarely present diagnostic
problems, as they are usually associated with at least some degree of acoustic shadowing. However, PEF, which
may represent psammoma bodies in
papillary cancers, are less straightforward. Many PEF are not psammomatous and actually represent the back
ll f i t t Additi ll th
Figure 10
Figure 10: (a) Sagittal image of a 2.2-cm carcinoma in a 61-year-old man shows a lobulated margin (arrows),
a 2-point feature. The nodule also received 2 points for solid composition and 2 for hypoechogenicity, for a total of
6 points ( TR4). (b) Sagittal sonogram of a 1.2 cm carcinoma with an irregular (spiculated) margin in a 39-year-old
woman. In addition to 2 points for its irregular margin, the nodule was assigned 2 points for solid composition, 3
points for very low echogenicity, and 3 points for punctate echogenic foci, for a total of 10 points ( TR5).
Figure 11
Figure 11: Papillary carcinoma bulging the thyroid
border in a 24-year-old woman. No invasion was
demonstrated at surgery. The nodule received 2
points for solid composition, 2 for hypoechogenicity,
3 for taller-than-wide shape, and 2 for a lobulated
margin Its point total was 9 (TR5)
makes it impossible to determine a
nodule’s echogenicity, it is assumed to
be at least isoechoic or hyperechoic
and receives 1 point in this category.
Shape
Like echogenicity, a nodule’s shape
(wider-than-tall or taller-than-wide) is
rarely difficult to define. “Tallness” refers to a nodule’s anteroposterior dimension and “width” to its transverse
dimension on an axial image. A gestalt
impression of whether a nodule is taller-than-wide is usually sufficient (Fig 8).
The goal is to ascertain whether the
nodule has grown more front-to-back
than side-to-side, which suggests that
it h i l t d ti l d i
-----
speckle pattern of normal or nonmalignant thyroid tissue may at times
contain minute bright dots that should
not be misinterpreted as PEF (Fig 12).
Therefore, we do not report them unless they are discrete and appear only
within the nodule, not in adjacent thyroid tissue. This pitfall may be avoided
by scrutinizing the suspicious tissue
and adjacent parenchyma. If dots are
present in both, they are probably not
PEF for the purpose of ACR TI-RADS
classification. The only exception is the
diffuse sclerosing variant of papillary
carcinoma, which should not present a
problem in diagnosis (13).
ACR TI-RADS distinguishes be
tween small and large comet-tail artifacts. The latter, which are larger than
1 mm and are V shaped, are associated
with colloid and are reliable signs of benignity when found in the cystic components of nodules. On the other hand,
small comet-tail artifacts should be
treated as PEF and therefore receive 3
points when embedded in hypoechoic,
solid tissue (Fig 13) (14). If both types
coexist in a nodule, the more suspicious
one determines how many points to assign. The central tenet is that the mere
presence of any comet-tail artifacts
should not be grounds for concluding
that a nodule is benign.
When different types of echogenic
foci are present, the points for each type
are summed to determine the overall
point total for echogenic foci. For instance, a nodule containing both peripheral calcifications and macrocalcifications
would be assigned 3 points in this category (1 point for macrocalcifications plus
2 points for peripheral calcifications).
This differs from the other categories, in
which the single finding with the highest
point value is used to determine the point
assignment for that feature.
Figure 12
Figure 13
Reports of thyroid sonograms should
include the following elements:
1. Tridimensional measurements of
the right and left lobes and the anteroposterior dimension of the isthmus.
2. An overall description of the thy
roid parenchyma.
3. Formal description of up to the
four most suspicious nodules.
4. Recommendations for
management.
Nodules not reported formally may
be mentioned in the overall description
by calling attention to them and stating that none warrant FNA or follow-up
US per ACR TI-RADS. The sole exception is when a US study is performed
to evaluate a nodule that was palpated
or detected at another imaging examination. Even if no further action is required, the nodule in question should
be formally reported, along with any
suspicious incidental nodules.
Per ACR TI-RADS, glands that con
tain multiple nodules with similar US
characteristics usually do not warrant
biopsy because it is impractical to sample every nodule. There is no evidence
to suggest that performing FNA on the
largest nodule improves patient out
F hi d
Figure 13: Small comet-tail artifacts and
additional echogenic foci (punctate echogenic foci
[PEF ]) in a papillary carcinoma in a 54-year-old
woman. In addition to 3 points for PEF, the nodule
was assigned 2 points for solid composition, 2 for
hypoechogenicity, and 2 for a lobulated margin, for a
total of 9 points ( TR5).
When this occurs, this limitation should
be noted in the report.
Reporting Considerations
Measuring Nodules: How to Reduce
Errors
ACR TI-RADS recommends measuring
a nodule’s longest axis and the largest
dimension perpendicular to the longest
axis on a transverse (axial) image and
the largest craniocaudal dimension on
itt l i Th t
Figure 12: Sonogram of the left thyroid lobe in
a 42-year-old man. Minute bright dots representing the speckle pattern of normal or nonmalignant
tissue (arrow) should not be misinterpreted as
punctate echogenic foci.
usually lie parallel or perpendicular to
the sound beam, but they will be angled
if the nodule is obliquely oriented. Regardless, nodules should be measured
by using the same technique that was
used in prior studies to assess growth,
which may be based on changes in linear measurements or volume.
To improve consistency on follow-up
examinations, sonographers/sonologists
should review prior sonograms to determine which nodules may warrant continued attention and see how they were
measured. Current US systems equipped
with high-frequency linear array transducers achieve very high spatial resolution. In practice, however, measurement
accuracy is hampered by interobserver
variability that is chiefly related to poor
border conspicuity. This limitation, which
is a property of the interface between the
nodule and its surroundings, can be mitigated by meticulous technique, but not
eliminated entirely.
As with other features, scanning pa
rameters play an important role. Notably,
settings that would be inappropriate for
characterizing internal architecture may
enhance the visibility of a nodule’s margin. For example, lowering the dynamic
range or altering pre- and postprocessing
settings may make it easier to distinguish
the nodule from adjacent tissue, making
it easier to tell where to place measurement calipers. Despite the imager’s best
efforts, however, some nodules cannot be
measured reliably if they are poorly defi d d i h h i di
-----
that at least a brief assessment of
nodes may be helpful in determining
the need for biopsy in the setting of
thyroid nodules. This practice is in
keeping with scanning protocols from
professional organizations (3,4). If a
node has a suspicious appearance,
but there are no thyroid nodules that
warrant FNA, the node should be
sampled. In some patients, it may be
appropriate to biopsy a suspicious
nodule that does not meet the size
threshold for its ACR TI-RADS level.
A comprehensive evaluation of nodes
is required in patients known to have
or suspected of having thyroid cancer.
It may be performed at the time of the
initial thyroid US examination, in conjunction with a US-guided biopsy, or
as a separate preoperative US evaluation after a cancer diagnosis has been
made with biopsy.
ACR TI-RADS does not specify
what to recommend for nodules that
have been sampled previously. Radiologists may defer decisions regarding follow-up US or repeat FNA to
referring physicians, who may have
information regarding previous biopsy results that are unavailable to
the radiologist interpreting a thyroid
sonogram. Decisions regarding the
need for repeat biopsy will usually be
made by the referring physician based
on guidelines from the American Thyroid Association or other professional
groups (3).
It is also important to recognize
that even benign nodules may assume a more suspicious appearance
following biopsy, causing them to
appear more solid, hypoechoic, or
calcified. These so-called mummified nodules will have a higher ACR
TI-RADS score, but recent evidence
suggests that such nodules should be
approached more conservatively and
can likely be safely followed with US
rather than repeat FNA, regardless of
their score (17).
ACR TI-RADS borrows from the
American Thyroid Association guideli d d fi li i ll i t t
Figure 14
Figure 14: Structured template for American College of Radiology (ACR) Thyroid Imaging Reporting
and Data System ( TI-RADS) reporting.
against the designation “dominant
nodule,” which is often applied to the
largest nodule in the gland. Biopsy is
recommended only if one or two nodules have high point totals that would
warrant FNA, regardless of whether
multiple nodules are present.
We have found that formal report
ing is faster with structured report templates that include the elements in ACR
TI-RADS (Fig 14). Such templates are
easy to implement in any voice recognition system. With practice, we have
found that it takes no more than approximately 20 seconds to report each
nodule. This approach also makes it easier for referring physicians to read and
understand reports, as well as to implement quality assurance and control procedures and peer review.
The ACR TI-RADS chart provides
descriptors for each of the five suspicion levels: benign (TR1), not suspicious (TR2), mildly suspicious (TR3),
moderately suspicious (TR4), and
highly suspicious (TR5). In a recent
study, they were associated with aggregate cancer risks of 0.3%, 1.5%, 4.8%,
9.1%, and 35.0%, respectively (15).
The ACR TI-RADS recommendations
for FNA and follow-up were in part informed by the growing recognition that
many thyroid cancers are indolent and
unlikely to cause harm to patients duri th i lif ti (16) N th l
recognize that patients are increasingly
able to view imaging reports though
portals and other means and that they
may be concerned that an 8-mm TR4
nodule described as “moderately suspicious” will not be sampled for biopsy
or even followed up. For this reason,
radiologists may elect not to mention
the risk descriptors in reports.
By no means are we advocating
withholding information; rather, we
wish to avoid misinterpretation by patients who may not fully understand
the difference in clinical importance
between a moderately suspicious thyroid nodule and a similarly suspicious
pulmonary lesion. Alternatively, radiologists may report aggregate risks or
risk ranges. We also believe that radiologists should discuss reporting preferences with referring physicians to avoid
misunderstandings.
Every report that includes one or
more formally reported nodules must
also provide recommendations for management, whether FNA, follow-up US,
or no further action. We believe that
statements such as “clinical correlation is
needed to determine the need for biopsy”
should be avoided. Endocrinologists and
other referring physicians should be expected to apply reasonable standard-ofcare principles in deciding whether to follow the radiologist’s recommendations.
For example, a highly suspicious nodule
in a patient with a limited life expectancy
or other issues may not require biopsy.
Conversely, patient or referring
physician preferences may at times
warrant deviation from the strict ACR
TI-RADS guidelines. Patients with a
strong personal or family history that
increases the likelihood of cancer, or
patients who are highly concerned for
other reasons, may require FNA and/or
follow-up of nodules that fall below
ACR TI-RADS size thresholds. This involves the radiologist in shared decision
making that is appropriate for effective
medical care. Similarly, ACR TI-RADS
recommends FNA of no more than two
nodules in one gland, but circumstances
may rarely require tissue sampling of
more than two nodules.
ACR TI-RADS does not encompass
i l l h d b t b li
Growth and Follow-up
-----
growth as a 20% increase in at least
two nodule dimensions and a minimal increase of 2 mm, or a 50% or
greater increase in volume (3). If a
nodule enlarges to the point where
it exceeds the size threshold for its
ACR TI-RADS level, we recommend
FNA, if this has not already been
performed. Although rapid enlargement is suspicious, growth does not
reliably distinguish between benign
and malignant nodules (18). However,
nodules that do not grow substantially
over the course of 5 years (based on
comparison between initial and 5-year
sonograms) may be considered benign. Nodules that exhibit an interval
increase in ACR TI-RADS level but
remain below the size threshold for
FNA should be imaged with follow-up
US in 1 year.
lignancy. Korean J Radiol 2012;13(5):530–
535.
10. Kim DW, Lee EJ, In HS, Kim SJ. Sono
graphic differentiation of partially cystic thyroid nodules: a prospective study. AJNR Am
J Neuroradiol 2010;31(10):1961–1966.
11. Kim DW, Park JS, In HS, Choo HJ, Ryu
JH, Jung SJ. Ultrasound-based diagnostic
classification for solid and partially cystic
thyroid nodules. AJNR Am J Neuroradiol
2012;33(6):1144–1149.
12. Kim EK, Park CS, Chung WY, et al. New
sonographic criteria for recommending
fine-needle aspiration biopsy of nonpalpable solid nodules of the thyroid. AJR Am J
Roentgenol 2002;178(3):687–691.
13. Jung HK, Hong SW, Kim EK, Yoon JH,
Kwak JY. Diffuse sclerosing variant of papillary thyroid carcinoma: sonography and
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14. Malhi H, Beland MD, Cen SY, et al. Echo
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15. Middleton WD, Teefey SA, Reading CC, et
al. Multiinstitutional analysis of thyroid nodule risk stratification using the American
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16. Brito JP, Davies L, Zeballos-Palacios C,
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Conclusion
The ACR TI-RADS risk-stratification
system allows practitioners to determine whether thyroid nodules require
biopsy, follow-up, or no further action
based on their US appearance. Success demands close cooperation between radiologists and sonographers,
understanding of the nuances and pitfalls of feature assignments, and attention to detail in reporting and making
recommendations.
**Disclosures of Conflicts of Interest: F.N.T.**
Activities related to the present article: disclosed no relevant relationships. Activities not
related to the present article: author received
payment from North Carolina Radiological
Society to lecture on ACR TI-RADS at ultrasound course. Other relationships: disclosed
no relevant relationships. W.D.M. disclosed
no relevant relationships. E.G.G. disclosed no
relevant relationships.
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mri-burn-prevention-poster/. Published November 16, 2015. Accessed January 25,
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Biparametric Prostate MR Imaging Protocol: Time to Revise PI-RADS Version 2?
From
Arnaldo Stanzione, MD, Sirio Cocoz
za, MD, Renato Cuocolo, MD, and
Massimo Imbriaco, MD
Department of Advanced Biomedical
Sciences, Federico II University
of Naples, Via Pansini 5, Naples
80131, Italy
e-mail: massimo.imbriaco@unina.it
Editor:
With great interest, we read the Letters to the Editor by Dr Scialpi and colleagues (1) in the January 2018 issue
of Radiology and Drs Kaji and Inamura
(2) in the February 2018 issue of Radi_ology commenting on the article by Dr_
Kuhl et al in the July 2017 issue of Ra_diology (3) about a possible reduction_
in acquisition time of multiparametric
magnetic resonance (MR) imaging of
the prostate. In particular, Dr Kuhl and
colleagues investigated the diagnostic
accuracy of a shortened biparametric
MR imaging protocol composed by the
sole evaluation of axial T2-weighted and
diffusion-weighted imaging. The authors showed how this approach led to
a similar diagnostic performance in the
detection of prostatic lesions compared
with the standard multiparametric MR
imaging protocol. In the first letter, Dr
Scialpi and colleagues (1) pointed out
that the elimination of sagittal and coronal T2-weighted images could make
it difficult to measure both prostate
and lesion volume, as well as to perform targeted biopsy when using fusion systems that require these planes.
Furthermore, Dr Scialpi and colleagues
suggested that the sagittal plane is essential for the assessment of extraglandular disease. On the other hand, Drs
Kaji and Inamura pointed out that, in
the article by Dr Kuhl and colleagues,
patients were considered having a positive index test result when they had a
Prostate Imaging Reporting and Data
System (PI-RADS) score of 3, 4, or 5
(2–3). In this setting, considering that
dynamic contrast-enhanced (DCE)
evaluation allows only for an upgrade
of PI-RADS score from 3 to 4 (4), it
is clear that its possible contribution to
a correct diagnostic assessment is not
significant. Our opinion, which is consistent with data available in the literature, is that biparametric MR imaging
offers clear and significant advantages
over standard multiparametric MR imaging, providing a similar diagnostic accuracy but leading to a significant reduction of acquisition time, which is
directly related to both patient discomfort and costs (5). Future studies are
strongly warranted to better identify
and evaluate all possible strategies and
combination of T2-weighted imaging
and diffusion-weighted imaging, considering all advantages and disadvantages of their combination. However, in
the transition from PI-RADS version 1
to PI-RADS version 2, the role of MR
spectroscopy and DCE imaging was already reappraised and reduced, and at
the time further concerns regarding the
usefulness of DCE were raised (6). In
light of the recently published articles
on shortened biparametric MR imaging
prostatic protocols (3,5,7), our opinion
is that DCE should no longer be considered mandatory and its role further revised within a new and up-to-date version of PI-RADS.
**Disclosures of Conflicts of Interest: A.S. dis-**
closed no relevant relationships. **S.C. Activities**
related to the present article: disclosed no relevant relationships. Activities not related to the
present article: received payment for lectures
including service on speakers bureaus from
Sanofi Genzyme. Other relationships: disclosed
no relevant relationships. R.C. disclosed no relevant relationships. **M.I. disclosed no relevant**
relationships.
References
1. Scialpi M, Martorana E, Aisa MC, Rondoni
V, D’Andrea A, Brunese L. Abbreviated biparametric prostate MR imaging: is it really an
alternative to multiparametric MR imaging?
Radiology 2018;286(1):360–361.
2. Kaji Y, Inamura K. Diagnostic ability with
abbreviated biparametric and full multiparametric prostate MR imaging: is the use of PIRADS version 2 appropriate for comparison?
Radiology 2018;286(2):726–727.
3. Kuhl CK, Bruhn R, Krämer N, Nebelung S,
Heidenreich A, Schrading S. Abbreviated biparametric prostate MR imaging in men with
elevated prostate-specific antigen. Radiology
2017;285(2):493–505.
4. Weinreb JC, Barentsz JO, Choyke PL, et
al. PI-RADS prostate imaging–reporting
and data system: 2015, version 2. Eur Urol
2016;69(1):16–40.
5. Stanzione A, Imbriaco M, Cocozza S, et al.
Biparametric 3T magnetic resonance imaging for prostatic cancer detection in a
biopsy-naïve patient population: a further
improvement of PI-RADS v2? Eur J Radiol
2016;85(12):2269–2274 [Published correction appears in Eur J Radiol 2017;87:125.].
6. Rud E, Baco E. Re: Jeffrey C. Weinreb,
Jelle O. Barentsz, Peter L. Choyke, et al. PIRADS Prostate Imaging—reporting and data
system: 2015, version 2. Eur Urol 2016;69:1640. Is contrast-enhanced magnetic resonance
imaging really necessary when searching for
prostate cancer? Eur Urol 2016;70(5):e136.
7. Barth BK, De Visschere PJL, Cornelius A, et
al. Detection of clinically significant prostate
cancer: short dual-pulse sequence versus
standard multiparametric MR imaging—a
multireader study. Radiology 2017;284(3):
725–736.
Erratum
**Originally published in:**
Radiology 2018;287(1):29–36
DOI: 10.1148/radiol.2017171240
Thyroid Imaging Reporting and Data
System (TI-RADS): A User’s Guide
Franklin N. Tessler, William D.
Middleton, and Edward G. Grant
**Erratum in:**
Radiology 2018;287(3):1082
DOI:10.1148/radiol.2018184008
Figure 9 legend should read as follows:
Transverse sonogram in a 52-year-old
woman shows a benign follicular nodule with a smooth margin (arrows). The
nodule was assigned 2 points for solid
composition and 1 for isoechogenicity,
for a total of 3 points (TR3).
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