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1 Division of Abdominal Imaging and Interventional Radiology, Department of
Radiology, Massachusetts General Hospital, 55 Fruit St., White 270, Boston, MA
02114.
2 Department of Radiology, University of Washington, Seattle, WA.
Received November 29, 2007;
accepted after revision November 29, 2007.
Address correspondence to H. B. Prabhakar.
Abstract
Keywords: CT • MRI • radiography • sarcoidosis
REQUIRED READING (available at www.arrs.org)
 TopAbstractINTRODUCTIONEDUCATIONAL OBJECTIVES REQUIRED READING (available at... RECOMMENDED READINGINSTRUCTIONSQUESTION 1QUESTION 2QUESTION 3QUESTION 4QUESTION 5QUESTION 6QUESTION 7QUESTION 8QUESTION 9QUESTION 10References |
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Solution to Question 1
Although sarcoidosis can involve the lymph nodes, liver, spleen, and CNS,
mortality is most commonly secondary to cardiopulmonary involvement
[1]. Sarcoidosis has a
1–5% mortality rate. Option E is the best response; options A, B,
C, and D are not. Patients with pulmonary sarcoidosis can present with
lymphadenopathy and pulmonary parenchymal disease, which can progress to
pulmonary fibrosis. Spontaneous remission of pulmonary disease is seen more
commonly in patients with stage I disease (lymphadenopathy alone) than in
patients with more advanced stages.
Solution to Question 2
Patients with sarcoidosis can present with a variety of symptoms. Dyspnea
and cough can lead to chest radiography in a number of patients. A clinical
staging system based on chest radiography has been devised, ranging from stage
0 (no radiographic abnormality) to stage IV (pulmonary fibrosis)
[1]. Option B is the best
response. Although imaging abnormalities can be seen on CT, FDG PET, and
gallium-67 scans, clinical staging systems have not been devised for these
modalities. Options A, C, D, and E are not the best responses.
Solution to Question 3
Peribronchovascular nodules are the most common manifestation of pulmonary
sarcoidosis [2]. Option A is
the best response. Alveolar consolidation can be seen; however, this
finding is less common. Option B is not the best response. Centrilobular,
solitary, and miliary nodules are not characteristic of pulmonary sarcoid.
Options C, D, and E are not the best responses.
Solution to Question 4
Increased FDG uptake within the bowel has not been described in the
literature from sarcoidosis
[2–4].
Option D is the best response. Within the abdomen, increased FDG uptake
from sarcoidosis can be seen within lymph nodes and bone, as well as within
focal lesions in the spleen and liver
[2–4].
Options A, B, C, and E are not the best responses.
Solution to Question 5
FDG uptake in sarcoidosis is nonspecific in both intensity and pattern.
Combining the imaging features of sarcoidosis on MDCT with the degree of FDG
uptake, FDG PET and PET/CT can be useful in monitoring the effectiveness of
therapy for sarcoidosis [5].
Option C is the best response. FDG PET is not useful in making an
initial diagnosis of sarcoidosis
[6]. Option A is not the best
response. In addition, because FDG uptake in patients with sarcoidosis can
mimic malignancies such as lymphoma and diffuse metastatic disease, imaging
with FDG PET is not useful in excluding malignancy or preventing the need for
pathologic diagnosis in most patients
[7]. Options B and D are not
the best responses. FDG PET uptake in sarcoidosis has not been shown in the
literature to be predictive of clinical progression. Option E is not the best
response.
Solution to Question 6
On MDCT, FDG PET, and PET/CT, the most common finding in patients with
sarcoidosis is diffuse lymphadenopathy, which can be massive in 10% of
patients [2]. As such, the most
common differential diagnosis in these patients is lymphoma
[7–9].
Option A is the best response. In patients with HIV, increased gallium
uptake within lacrimal and parotid glands can be shown; however, uptake is not
typically bilateral and symmetric as seen in sarcoidosis. Option B is not the
best response. Increased uptake has been described on both bone scintigraphy
and FDG PET in skeletal sarcoidosis; however, diffuse bone involvement is a
less common feature of sarcoidosis than lymphadenopathy. Option C is not the
best response. Although pulmonary involvement is common in sarcoidosis,
imaging features do not commonly overlap with primary lung cancer or pulmonary
tuberculosis. Options D and E are not the best responses.
Solution to Question 7
Acute myocardial inflammation by sarcoidosis is the result of infiltration
of the myocardium by noncaseating granulomas and surrounding edema. The
appearances of this process on MRI include intramyocardial focal zones or
nodules of high T2 signal, focal myocardial thickening, and segmental
contraction abnormalities
[10]. These features overlap
with those of other causes of acute myocardial inflammation. Options A, B, C,
and E are true and, therefore, are not the best responses. Subendothelial
nodules with susceptibility have not been described in association with
myocardial sarcoidosis. Option D is false and is the best response.
Solution to Question 8
In a series of 40 patients with established sarcoidosis and musculoskeletal
symptoms, Moore et al. [11]
found marrow and soft-tissue lesions that were occult or underestimated on
radiographs. Option A is true and is not the best response. Marrow lesions in
the large bones and axial skeleton were indistinguishable from metastases on
standard MRI protocols. Option B is false and is the best response.
Abnormalities in the soft tissues included muscle edema, muscle atrophy, and
nodular muscle lesions that enhanced after gadolinium administration. Option C
is true and is not the best response. Joint involvement included synovitis,
tenosynovitis, effusions, subarticular bone marrow edema, subchondral cysts,
and erosions. Option D is true and is not the best response.
Solution to Question 9
The prevalence of liver and spleen involvement in sarcoidosis is
approximately 40–60% for each, according to autopsy series
[12]. Options A and B are not
the best responses. Involvement of the pancreas is rare, perhaps 1% of
patients. Option C is the best response. Abdominal adenopathy, two or
more nodes with a short-axis dimension of 1 cm or greater, or nodes in the
retrocrural area with a short-axis dimension of 6 mm or greater occur in
approximately 30% of patients. Option D is not the best response.
Solution to Question 10
The liver is commonly involved in sarcoidosis, but symptoms of liver
involvement are relatively uncommon
[12]. The liver may be
homogeneously or heterogeneously enlarged or focal abnormalities, such as
nodules, may be present. On contrast-enhanced CT, the nodules are
hypoattenuating relative to background liver parenchyma. Option A is true and
is not the best response. On MRI, the nodules are hypointense on T1-weighted
images, hypointense on T2-weighted images, and hypoenhancing after gadolinium
infusion. Option C is false and is the best response; options B and D
are true and are not the best responses. On sonography, nodules have been
reported as being both hypoechoic or hyperechoic relative to background liver.
Option E is true and is not the best response.
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