Endoscopic ultrasound in the diagnosis of chronic pancreatitis

Abstract

Diagnosis of chronic pancreatitis (CP) remains a challenge. Endoscopic ultrasound (EUS) can be considered nowadays as the technique of choice for the morphological diagnosis of this disease. More than three or four EUS defined criteria of CP need to be present for the diagnosis of the disease. The development of the more restrictive Rosemont classification aims to standardize the criteria, assigning different values to different features but its impact on the EUS-based diagnosis of CP is debatable. A combined use of endoscopic function test and EUS has even increased the diagnostic yield. Elastography and FNA may be also of help for diagnosing CP. EUS also provides with very valuable information on the severity of the disease, giving key information that may influence in the treatment. Differential diagnosis of solid pancreatic masses in the context of a CP is also challenging, EUS plays a key role in this context. It provides with the possibility of obtaining specimens for histopathological diagnosis. Nowadays, new developed techniques associated to EUS, like elastography and contrast enhancement, are also showing promising results for the differentiating between these pancreatic lesions.

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REVIEW
Rev esp enfeRm Dig (Madrid
Vol. 107, N.º 4, pp. 221-228, 2015
Endoscopic ultrasound in the diagnosis of chronic pancreatitis
Julio Iglesias-García1, José Lariño-Noia1, Björn Lindkvist1,2 and J. Enrique Domínguez-Muñoz1
1Department of Gastroenterology and Foundation for Research in Digestive Diseases (FIENAD). Hospital Universitario de Santiago. Santiago de Compostela.
A Coruña, Spain. 2Institute of Medicine. Sahlgrenska Academy. University of Gothenburg. Gothenburg, Sweden
1130-0108/2015/107/4/221-228
Revista española De enfeRmeDaDes Digestivas
CopyRight © 2015 aRán eDiCiones, s. l.
ABSTRACT
Diagnosis of chronic pancreatitis (CP) remains a challenge.
Endoscopic ultrasound (EUS) can be considered nowadays as the
technique of choice for the morphological diagnosis of this disease.
More than three or four EUS defined criteria of CP need to be
present for the diagnosis of the disease. The development of the
more restrictive Rosemont classification aims to standardize the
criteria, assigning different values to different features but its impact
on the EUS-based diagnosis of CP is debatable. A combined use of
endoscopic function test and EUS has even increased the diagnostic
yield. Elastography and FNA may be also of help for diagnosing CP.
EUS also provides with very valuable information on the severity
of the disease, giving key information that may influence in the
treatment. Differential diagnosis of solid pancreatic masses in the
context of a CP is also challenging, EUS plays a key role in this
context. It provides with the possibility of obtaining specimens for
histopathological diagnosis. Nowadays, new developed techniques
associated to EUS, like elastography and contrast enhancement,
are also showing promising results for the differentiating between
these pancreatic lesions.
Key words: Endoscopic ultrasound. Diagnosis. Chronic
pancreatitis.
INTRODUCTION
Chronic pancreatitis (CP) is a progressive and irrevers-
ible inflammation of the pancreatic gland that ultimately
leads to fibrosis and destruction of normal tissue resulting
in morphological alterations and exocrine as well as endo-
crine dysfunction (1). The diagnosis is easy to establish in
advanced stages of the disease, when the presence of pan-
creatic calcifications, atrophy of the gland and pancreatic
duct dilation can be visualized by conventional imaging
techniques such as abdominal ultrasound and computed
tomography. Early CP, on the other hand, remains a major
diagnostic challenge today. Pathological specimens from
the pancreas are very difficult to obtain and there is no
clear international consensus of a histological or clinical
definition of CP.
Endoscopic retrograde cholangiopancreatography
(ERCP) has previously been considered as the gold stan-
dard for the diagnosis of CP. However, due to the possible
and serious complications related to the procedure and the
fact that the parenchyma is not visualized, ERCP is no lon-
ger considered the method of choice (2). Among pancreatic
function tests, the secretin test has been demonstrated to
have a high sensitivity and specificity for CP (3). The use
of this test has been limited since it is difficult to perform
and not widely available (4). Endoscopic ultrasonography
(EUS) has emerged as a promising diagnostic technique
for pancreatic disease since it is able to detect pancreatic
parenchymal and ductal changes with high sensitivity. Fur-
thermore, fine needle biopsies can be obtained by EUS for
cytological or histological evaluation, and CP related com-
plications could be treated with EUS guided interventions.
The use of EUS for the diagnosis of CP will be reviewed
in this article.
EUS IN THE DIAGNOSIS OF CHRONIC
PANCREATITIS
EUS has the ability to produce high-resolution ultraso-
nography images of the pancreas due to the proximity of
the transducer to the gland, avoiding interference by air in
the intestine. EUS diagnosis of CP is based on specific cri-
teria that have been described by the International Working
Group for Minimum Standard Terminology in Gastroin-
testinal Endoscopy (5). These comprise five parenchymal
criteria (hyperechoic foci, hyperechoic strands, parenchy-
Iglesias-García J, Lariño-Noia J, Lindkvist B, Domínguez-Muñoz JE. Endo-
scopic ultrasound in the diagnosis of chronic pancreatitis. Rev Esp Enferm
Dig 2015;107:221-228.
Received: 23-12-2014
Accepted: 21-01-2015
Correspondence: Julio Iglesias-García. Gastroenterology Department. Foun-
dation for Research in Digestive Diseases (FIENAD). Hospital Universitario
de Santiago. c/ Choupana, s/n. 15706 Santiago de Compostela. A Coruña,
Spain
e-mail: julio.iglesias.garcia@sergas.es
Disclosures: Dr. Julio Iglesias-García is international advisor of Cook-Med-
ical. Dr. J. Enrique Domínguez-Muñoz has acted as international advisor of
Pentax Medical Company.

222 J. IGLESIAS-GARCÍA ET AL. Rev esp enfeRm Dig (maDRiD)
Rev esp enfeRm Dig 2015; 107 (4): 221-228
mal lobularity, cysts, calcifications) and five ductal crite-
ria (pancreatic duct dilation, pancreatic duct irregularity,
hyperechoic pancreatic duct walls, visible pancreatic side
branches, intraductal calcifications) (Fig. 1). The number
of criteria that is needed to establish the diagnosis of CP
and the relative weight of each criterion has been a matter
of debate for several years. The first attempts to create an
integrated evaluation of EUS based CP findings simply
used the sum of positive criteria and defined EUS findings
consistent with CP as a certain minimum number of pos-
itive criteria (6,7). In an attempt to allow for differentiat-
ed weighting of CP criteria and to harmonize EUS based
diagnosis of CP, the Rosemont classification was published
in 2009 (8). The Rosemont classification is a definition of
EUS based CP criteria produced by a group of endosonog-
raphy experts at an international consensus conference.
Ductal and parenchymal EUS findings are divided into
major A, major B and minor criteria (Table I). As opposed
to the previous simple counting of criteria, the Rosemont
classification gives different weight to different findings.
Based on the number and character of positive EUS crite-
ria, EUS evaluation is classified as “consistent with CP”,
“suggestive of CP”, “indeterminate for CP”, or “normal”
(8) (Table II). This system agrees with the standard clas-
sification in 74% of cases, increasing to 84% when “sug-
gestive of CP” was included as CP (8).
One of the most important weaknesses of EUS in the
diagnosis of CP is concern about poor interobserver agree-
ment (9). Interobserver agreement differs between EUS
criteria. Duct dilation and lobularity (10) was demon-
strated to have the highest agreement in one study while
hyperechoic strands and parenchymal cysts were found
to have the highest agreement in another study (11). Inter
observer agreement for standard EUS classification versus
Rosemont classification for CP has been evaluated in a
multicenter study. Fourteen experts evaluated 50-recorded
videos using the standard EUS criteria (CP diagnosis if
≥ 3) and the Rosemont classification (considering “sugges-
tive of CP” and “consistent with CP” as positive findings).
Kappa score for inter observer agreement on the Rosemont
classification was 0.65, and the kappa score for standard
classification was 0.54 (n.s.). Best agreement was noted
for calcifications (standard scoring), pancreatic duct cal-
cifications (Rosemont classification) and pancreatic duct
dilation (both systems). The poorest agreement was seen
for lobularity without honeycombing (Rosemont classifi-
cation). Patients were correctly classified as definite CP in
91.2% of cases according to standard scoring and 83.5%
according to Rosemont classification; as mild CP in 50%
according to standard scoring and 42.9% according to
Rosemont classification; and not CP in 83.3% and 95.2%
of cases respectively (12). The inability of the Rosemont
classification to improve inter-observer agreement com-
pared to standard EUS criteria has thereafter been con-
firmed in a recent study (13). The use of radial or linear
echoendoscopes does not have a significant impact on inter
observer agreement (k = 0.50 and 0.61 respectively) (14).
EUS vs. pancreatic function test and EUS plus
endoscopic function test
Pancreatic function test have been used for diagnosis of
early CP. The pancreatic function test with the highest sen-
sitivity for CP is the secretin/cholecystokinin (CCK) stimu-
lation test with aspiration of duodenal content by a dreilling
tube or an endoscope during at least 45-60 minutes. The
sensitivity and specificity of this test for diagnosing CP
both exceed 90% (4). A high agreement between EUS and
the secretin test has been demonstrated in several studies.
Fig. 1. Different EUS criteria in a patient diagnosed of chronic pancreatitis (parenchymal: Lobularity, strands and foci [A]; ductal: Irregular MPD with
hyperchoic wall [B]).
A B

Vol. 107, N.º 4, 2015 ENDOSCOPIC ULTRASOUND IN THE DIAGNOSIS OF CHRONIC PANCREATITIS 223
Rev esp enfeRm Dig 2015; 107 (4): 221-228
By using 1-2 EUS criteria for mild pancreatitis, 3-5 for
moderate pancreatitis, and > 5 for severe forms, agree-
ment between classic secretin test and EUS was 100% for
normal parenchyma and severe disease, 50% for moderate
CP, and 13% for mild disease (3). Stevens et al used 4 EUS
criteria as cut-off and observed a sensitivity of around 70%
and a specificity of around 90% of EUS for prediction of
a pathological endoscopic function test, depending on if
CCK or secretin was used to simulate pancreatic secretion
(15). Comparison of EUS (3-5 criteria for diagnosis) and
ERCP showed quite similar sensitivity (72% vs. 68%) and
specificity (76% vs. 79%) for either mild or severe CP
with the endoscopic secretin test as the reference. EUS
worked significantly better for establishing the presence
of pancreatic exocrine insufficiency (PEI) (16). Six cri-
teria were needed to obtain the best specificity and best
negative predictive value, however sensitivity decreased
to only 26% (17,18).
A combined use of endoscopic function test and EUS
has recently been brought forward as a sensitive and accu-
rate method for early diagnosis of CP (19,20). The concept
is theoretically appealing since both morphology and exo-
crine function is evaluated. A standard EUS is performed,
secretin is administered intravenously and duodenal fluid
is subsequently collected at 15, 30, and 45 min. In a study
including 252 patients for suspected minimal change CP
(no calcifications), 160 (63.5%) had both normal EUS and
endoscopic function test results, excluding CP. Thirty-two
patients (12.7%) had abnormal EUS and abnormal endo-
scopic test results, confirming the diagnosis. The remain-
ing 60 patients had discordant results (21). Patients with
abnormal EUS and normal endoscopic function test may
have CP with preserved exocrine function, or a false posi-
tive result of EUS for CP. The significance of normal EUS
with abnormal function test is uncertain, but may suggest
a very early form of CP prior to the development of struc-
tural changes, or a false positive result of function test for
Table I. Consensus-based parenchymal and ductal features of CP according to the new Rosemont classification (adapted from
reference 8)
Feature Definition Major criteria Minor criteria
Hyperechoic foci with
shadowing Echogenic structures ≥ 2 mm in length and width that shadow Major A
Lobularity Well-circumscribed, ≥ 5 mm structures with enhancing rim
and relatively echo-poor center
A. With honeycombing Contiguous ≥ 3 lobules Major B
B. Without honeycombing Noncontiguous lobules Yes
Hyperechoic foci without
shadowing
Echogenic structures ≥ 2 mm in both length and width with
no shadowing Yes
Cysts Anechoic, rounded/elliptical
structures with or without septations Yes
Stranding Hyperechoic lines of ≥ 3 mm in length in at least 2 different
directions with respect to the imaged plane Yes
MPD calculi Echogenic structure(s) within MPD with acoustic shadowing Major A
Irregular MPD contour Uneven or irregular outline and ectatic course Yes
Dilated side branches 3 or more tubular anechoic structures each measuring ≥ 1 mm
in width, budding from the MPD Yes
MPD dilation ≥ 3.5-mm body or ≥ 1.5-mm tail Yes
Hyperechoic MPD margin Echogenic, distinct structure greater than 50% of entire MPD
in the body and tail Yes
Table II. EUS diagnosis of chronic pancreatitis (CP) based
on Rosemont consensus (adapted from reference 8)
I. Consistent
with CP
A. 1 major A feature (+) ≥ 3 minor features
B. 1 major A feature (+) major B feature
C. 2 major A features
II. Suggestive
of CP
A. 1 major A feature (+) < 3 minor features
B. 1 major B feature (+) ≥ 3 minor features
C. ≥ 5 minor features (any)
III. Indeterminate
for CP
A. 3 to 4 minor features, no major features
B. major B feature alone or with < 3 minor
features
IV. Normal ≤ 2 minor features, no major features

224 J. IGLESIAS-GARCÍA ET AL. Rev esp enfeRm Dig (maDRiD)
Rev esp enfeRm Dig 2015; 107 (4): 221-228
CP (21). Pancreatic morphology can also be dynamically
evaluated with EUS after secretin stimulation. The pan-
creatic duct dilates after secretin stimulation in the normal
pancreas. Dynamic EUS has demonstrated reduced pan-
creatic duct compliance as a consequence of duct fibrosis
in CP, most pronounced in the tail of the pancreas, and
duct compliance is negatively associated with bicarbonate
secretion (22).
EUS vs. ERCP
ERCP has previously been considered as the reference
method for early diagnosis of CP. Early studies on EUS
have used ERCP as gold standard for diagnosis of CP.
These studies have demonstrated a good overall agreement
between the tests and a sensitivity of 70-100% and a speci-
ficity of 80-100% of EUS (using > 2 criteria cut-off) (6,18).
Ductal stones and parenchymal calcifications are the EUS
findings that are associated with the highest probability of
an abnormal ERCP. Later studies have demonstrated that
ERCP may not be the appropriate reference method for
early diagnosis of CP and that EUS actually may be more
sensitive than ERCP (23). Kahl et al. identified 38 patients
with normal ERCP but EUS findings suggesting CP in a
cohort of 130 patients evaluated for known or suspected
CP. During follow-up, 69% of these patients with initially
normal findings on ERCP developed an abnormal pan-
creatogram (24).
EUS vs. magnetic resonance imaging
Magnetic resonance imaging (MRI) enhanced by gad-
olinium contrast after secretin stimulation together with
magnetic resonance cholangiopancreatography (MRCP) is
a highly accurate method for evaluation of CP (25). EUS
has been compared with MRI/MRCP for the diagnosis of
CP and similar sensitivity but a slightly superior speci-
ficity of EUS has been indicated (26). In the presence of
both abnormal EUS and MRI/MRCP the specificity for CP
diagnosis was 100% in that study (26). In our experience,
there is a very good correlation between EUS and secretin
MRCP in the evaluation of patients with a suspected CP
both in the global evaluation for diagnosing the disease
(both for parenchymal and ductal analysis). In fact, in 81%
of the cases, information provided by both techniques was
equivalent.
EUS vs. histology
Compared to pancreatic specimens, > 3 EUS standard
criteria predict histological findings of CP (27). However,
these EUS features have also been demonstrated in elderly
persons without signs of CP (28) and in 59% of asymptom-
atic alcohol abusers (20). Using histologic findings from
surgical specimens as reference, > 5 versus > 3 standard
EUS criteria diagnosed CP with a sensitivity of 60% versus
87% and specificity of 83% versus 64% (29). Varadarajulu
et al. demonstrated in a similar study where EUS findings
were compared to histology from surgical specimens that
hyperechogenic foci, stranding, lobularity or any ductal
aberrations were the EUS features that were significantly
associated with histological findings of CP. Four or more
standard criteria was the cut-off for CP diagnosis that pro-
vided the best accuracy in that study (30). In yet another
study on EUS findings versus surgical specimens, Chong
et al. found that 3 or more criteria was the cut-off that best
differentiated abnormal from normal pancreas (27). Stan-
dard EUS criteria appear as a poor predictor of histological
severity in these studies. Varadarajulu et al. did not find
any correlation between the number of EUS criteria and
histological severity and Chong et al. found only a weak,
although statistically significant, correlation between the
number of EUS criteria and the histological fibrosis score
(27,30). However, in a recent study, Leblanc et al. showed
that certain EUS criteria were associated with a severe
CP, as correlated with histological findings. These crite-
ria were lobularity with honeycombing, hyperechoic foci
with shadowing, dilated MPD, irregular MPD, and dilated
side branches. Authors also state that the importance of
pancreatic ductal changes should not be minimized in the
evaluation of CP (31).
EUS-guided fine needle aspiration and/or fine needle
biopsy
EUS-guided fine needle aspiration (FNA) and/or fine
needle biopsy (FNB) has a clear and well investigated role
in the differential diagnosis between mass forming chronic
pancreatitis and pancreatic cancer but studies on the use
of EUS guided tissue sampling in differentiating early CP
from normal tissue are scares. The possible and severe
complications related to the procedure and the lack of a
generally agreed histologic definition of CP further limits
today the use of EUS-guided FNA/FNB in the diagnosis of
early CP. Hollerbach et al investigated the value of adding
a 22-gauge needle FNA to standard EUS evaluation in a
series of 37 patients with a suspicion of CP with ERCP
as reference method. The addition of EUS-guided FNA
improved the negative predictive value of EUS (32). In a
small series of fourteen patients with alcohol related CP
undergoing EUS-guided FNA, we have observed presence
of inflammatory cells in all cases (33). Preserved pancre-
atic acini were observed in patients with mild to moderate
EUS changes of CP. In contrast, biopsies from more severe
cases (8-10 EUS criteria) showed only ductal epithelium
and fibrosis (33). Thus, it is possible that EUS-guided FNA
can be useful for both diagnosis and staging of CP. How-
ever, to date it is not clear if the benefits of FNA/FNB out-

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Rev esp enfeRm Dig 2015; 107 (4): 221-228
weighs the risks for complications related to the procedure
and the clinical use of FNA/FNB for diagnosis and staging
of CP remains to be established.
EUS-guided elastography and contrast enhancement
Elastography evaluates tissue strain resulting from com-
pression and that strain is smaller in harder tissue than in
softer tissue. Different tissue elasticity patterns are marked
supplementary on the grey-color scale with different colors
(blue for hard tissue and red for soft tissue). Today elas-
tography can also be evaluated in a quantitative manner
by calculating the ratio between the strain in the region
of interest and a reference area in surrounding soft tissue
(strain ratio) (34). The typical finding on qualitative elas-
tography in CP is a heterogeneous coloration with green
areas and blue strands, as opposed to normal pancreas that
presents a homogeneous, predominantly green and yellow
pattern (35). The accuracy of quantitative EUS-elastogra-
phy for the diagnosis of CP has been recently investigated.
A high correlation was found between the number of EUS
criteria and the pancreatic strain ratio. In addition, a signif-
icant difference in strain ratio between different Rosemont
classification categories was observed, with increasing
strain ratio when passing from normal pancreas to inde-
terminate for CP to suggestive for CP to consistent for CP
(36,37) (Fig. 2). More recently, a new study has shown a
very good correlation between the strain ratio, as evaluated
by quantitative EUS-elastography, and the probability of
suffering from exocrine pancreatic insufficiency (38). The
role of contrast enhanced EUS for the diagnosis of CP has
not been yet well established. Only one study has evaluated
the role of contrast enhanced EUS in this setting. Contrast
enhanced EUS enhances the lobular pattern seen by con-
ventional EUS in CP patients. Furthermore, the washout
of contrast is markedly faster in CP patients compared to
controls.
EUS for evaluating the severity degree of chronic
pancreatitis
Visible side branches, duct dilation, duct irregularity,
and calcifications have been demonstrated to be asso-
ciated with severe CP on ERCP (39) according to the
Cambridge classification (40). One study has shown that
odds ratio for pancreatic exocrine insufficiency (PEI)
(severe CP) by EUS was, in the presence of minimal
and severe structural changes 4.9 and 24, respectively
(16). In a recent study, the probability of PEI in relation
to EUS criteria of CP was analyzed. The percentage of
patients with PEI increased linearly with the number of
EUS criteria. The presence of intraductal calcifications,
hyperechogenic foci with shadowing, and dilation of the
main pancreatic duct were significantly and independent-
ly associated to PEI (Fig. 3). The probability of PEI in
the presence of calculi in the main pancreatic duct is 80%
and increases to 82.8% if, in addition, the main duct is
dilated. Thus EUS allows predicting the probability of
PEI and thus need for enzyme replacement therapy in
patients with CP (41).
DIFFERENTIAL DIAGNOSIS OF MASS
FORMING CHRONIC PANCREATITIS
AND PANCREATIC CANCER
Differential diagnosis of solid pancreatic masses
includes primary or secondary pancreatic tumor, focal
Fig. 2. Quantitative endoscopic ultrasound elastography in a patient with
findings suggestive of chronic pancreatitis.
Fig. 3. Advanced chronic pancreatitis evaluated by EUS, showing diffuse
calcifications, in patient diagnosis of pancreatic exocrine insufficiency.

226 J. IGLESIAS-GARCÍA ET AL. Rev esp enfeRm Dig (maDRiD)
Rev esp enfeRm Dig 2015; 107 (4): 221-228
CP and autoimmune pancreatitis. Despite high-resolu-
tion images produced by conventional EUS, differentia-
tion between benign inflammatory masses and malignant
tumors based on B-mode images remains a challenge.
EUS-FNA/FNB, contrast enhanced harmonic EUS and
EUS elastography are new tools to improve of the diag-
nostic accuracy of EUS for the evaluation of solid pancre-
atic masses.
EUS-guided FNA and FNB
The role of EUS-guided FNA in the diagnosis of solid
pancreatic tumors has been evaluated in several studies.
Reported sensitivity and accuracy for malignancy ranges
from 75 to 92% and from 79 to 92%, respectively (42).
This accuracy may be even higher using on-site evalu-
ation of the sample by an experienced pathologist (43).
However, it should be kept in mind that the sensitivity of
EUS-guided FNA for malignancy is lower (between 54%
and 74%) if the lesion is detected in the context of CP
compared to when the surrounding parenchyma is normal
(44-47). Furthermore, in some cases EUS-guided FNA
maybe not feasible due to technical difficulties or the EUS-
FNA samples are of low quality for diagnosis. In total,
EUS-guided FNA does not allow reaching the pathological
diagnosis of pancreatic masses in 8% to 25% of cases (48).
In order to optimize tissue retrieval of EUS-guided biopsy,
various new needles, like Tru-Cut and the new ProcoreTM
have been tested (49).
EUS-guided elastography
Pathological processes like cancer and fibrosis alter tis-
sue elasticity and will therefore induce changes in elasto-
graphic appearance. Qualitative elastography can differen-
tiate malignant from benign solid pancreatic lesions with a
sensitivity, specificity, positive and negative predictive val-
ues, and overall accuracy of 100%, 85.5%, 90.7%, 100%
and 94.0%, respectively (50). Quantitative EUS-elastog-
raphy is a more objective and accurate method than qual-
itative EUS-elastography. In a previous study including
86 consecutive patients with solid pancreatic masses, the
sensitivity and specificity of quantitative EUS-elastogra-
phy for the differentiation of malignant from benign lesions
were 100% and 92.9% respectively (51) (Fig. 4). Mean hue
histogram value is an alternative measure for quantitative
elastography. A first study showed a sensitivity, specificity,
and accuracy in differentiation of malignant from benign
masses of 91.4%, 87.9%, and 89.7%, respectively (52). A
multicenter study, using the same methodology, showed
a sensitivity of 93.4%, a specificity of 66.0%, a positive
predictive value of 92.5%, a negative predictive value of
68.9%, and an overall accuracy of 85.4% for the diagnosis
of pancreatic malignancy (53).
Contrast enhanced EUS
Administration of contrast agents is another way to
improve EUS-based diagnosis of solid pancreatic tumors.
Today, the most widely used is contrast enhanced harmon-
ic EUS (CEHEUS), technique that detects signals from
micro bubbles delivered by new contrast agents in vessels
with very slow flow without the burden of Doppler-re-
lated artifacts (54). With this technique pancreatic cancer
appears as a low enhanced lesion with a rapid washout,
while mass forming CP uses to appear as an isoenhanced
lesion. A hypoenhanced pattern has a high sensitivity for
adenocarcinoma (89-96%) but the specificity is lower since
advanced mass-forming CP also may be hyperenhanced
(55,56). Tissue perfusion after contrast administration can
be quantified using time intensity curve analysis. A recent
study has indicated that this quantitative method may
have a high sensitivity and specificity for differentiation
between pseudotumoral CP and pancreatic cancer (57).
Further larger multicenter studies are warranted in order
to investigate the role of quantitative and qualitative con-
trast enhanced EUS in the diagnosis of pancreatic cancer.
CONCLUSIONS
Diagnosis of CP remains a challenge. EUS can be con-
sidered nowadays as the technique of choice for the mor-
phological diagnosis of this disease. More than three or
four EUS defined criteria of CP need to be present for the
diagnosis of the disease. The development of the more
restrictive Rosemont classification aims to standardize the
criteria, assigning different values to different features but
its impact on the EUS-based diagnosis of CP is debatable.
A combined use of endoscopic function test and EUS has
even increased the diagnostic yield for the diagnosis of CP.
Fig. 4. Mass forming chronic pancreatitis at the pancreatic head,
evaluated by EUS-elastography.

Vol. 107, N.º 4, 2015 ENDOSCOPIC ULTRASOUND IN THE DIAGNOSIS OF CHRONIC PANCREATITIS 227
Rev esp enfeRm Dig 2015; 107 (4): 221-228
Elastography and FNA may be of help for diagnosing CP.
EUS also provides with very valuable information on the
severity of the disease, giving key information that may
influence in the treatment.
Differential diagnosis of solid pancreatic masses in the
context of a CP is also challenging, EUS plays a key role
in this context. It provides with the possibility of obtaining
specimens for histopathological diagnosis, improving its
diagnostic yield. Nowadays, new developed techniques
associated to EUS, like elastography and contrast enhance-
ment, are also showing promising results for the differen-
tiating between these pancreatic lesions.
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