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767
.4, Emil J. Baithazar, M.D.
John H.C Ranson, BM., B.Ch.David P. Naidich, M.D.
Alec J. Megibow, M.D.
I’ Robert Caccavale, M.D.Matthew M. Cooper, M.D.
Acute Pancreatitis: Prognostic Value
of CT1
In 83 patients with acute pancreatitis, theinitial computed tomographic (CT) ex-
A aminations were classified by degree ofdisease severity (grades A-E) and werecorrelated with the clinical follow-up,objective prognostic signs, and complica-
.� tions and death. The length of hospital-
ization correlated well with the severityof the initial CT findings. Abscesses oc-
.4 curred in 21.6% of the entire group, com-pared with 60.0% of grade E patients.Pleural effusions were also more commonin grade E patients. Grades A and B pa-
,� tients did not have abscesses, and nonedied, regardless of the number of prog-
F nostic signs. Abscesses were seen in 80.0%
I ‘� of patients with six to eight prognosticsigns, compared with 12.5% of those withzero to two. The use of prognostic signswith initial CT findings results in im-proved prognostic accuracy. Early CT ex-
� �4 amination of patients with acute pancrea-titis is a useful prognostic indicator of
� morbidity and mortality.
‘� Index terms: Pancreas, computed tomography,
77.1211 #{149}Pancreatitis, 77.291
Radiology 1985; 156:767-772
� From the Departments of Radiology (E.J.B., D.P.N.,
A.J.M.) and Surgery (J.H.C.R., R.C., M.M.C.), NewYork University Medical Center, Bellevue HospitalMedical Center, New York City. Received January 10,1985; accepted and revision requested March 18, 1985;
revision received April 3. 1985.c RSNA, 1985
T HE degree, duration, and type of treatment of acute pancreatitis
are based on the early evaluation of the initial attack’s severity.
Until recently, this evaluation relied mainly on the presence on
absence of varied clinical parameters such as tachycardia, fever,
dyspnea, oligunia, protracted ileus, and tense abdomen. Several
methods of a more objective evaluation have been reported (1-7)
that potentially improve prognostic ability and prediction of com-plications. Among them, the statistical analysis of early objective
measurements of multiple risk factors, described by Ranson (2, 3),
has received wide attention and has been considered a reliable
prognostic indicator of the diseases’s severity. These objective prog-
nostic signs (grave signs or risk factors) have significantly im-
proved the initial assessment based on clinical criteria alone and are
used as guidelines in the decision-making process of selecting
proper medical or surgical treatment in our institution.
Since morbidity and mortality depend in great measure on the
local pancreatic and penipancreatic complications (i.e., abscess,
pseudocyst, hemorrhage), computed tomographic (CT) examina-
tion could play an important role in the initial assessment of the
severity of acute pancneatitis. For this reason, in the past 4 years wehave embarked on a comprehensive study designed to assess the
prognostic value of the initial CT examination in patients with
acute pancreatitis. Our objectives are (a) to describe, classify, andanalyze the early CT findings in acute pancreatitis; and (b) to assess
their predictive value based on correlation of early CT findings
with clinical and objective prognostic signs.
MATERIALS AND METHODS
Our study is based on a detailed analysis of CT, clinical, and laboratory
findings of 83 patients with acute pancreatitis admitted to our institution in
the past 4 years. There were 63 men and 20 women, aged 17-79 years, with a
mean age of 45 years. The clinical diagnosis was based on typical symptoms
such as nausea, vomiting, abdominal pain, and elevation of serum amylase
levels above 200 Somogyi units. The etiology of pancreatitis was chronic
alcohol abuse in 51 patients, cholelithiasis in 11, gallstones and alcohol in
five, hyperlipidemia in two, and miscellaneous or unknown in 14. There
were no cases of traumatic pancreatitis included in this series.
We used the previously reported objective prognostic signs (2, 3, 6, 7),
listed in Table 1, to assess the severity of the attack and its possible compli-
cations. All patients were initially treated by nasogastric suction, intrave-
nous fluid, and supportive therapy. We drained infected fluid collections
(abscesses) in 18 patients (21.7%), some upon initial evaluation and others as
complications developed. The clinical course, complications, treatment,
and response to treatment were recorded for all individuals, until death or
discharge from the hospital.
CT examinations were performed on a GE 8800 scanner (Milwaukee)
using standard technical parameters. Diluted 2% barium sulfate (E-Z-CAT,
E-Z-EM, Westbury, N.Y.) was used as oral contrast material, and a rapid
intravenous drip infusion of 30% diatrizoate meglumine (Reno-M-DIP
[Squibb]) was started immediately before scanning unless contraindicated.
Bolus injections were not used in this study.
A total of 152 CT scans were obtained, either as a single examination or as
consecutive, follow-up examinations approximately every 2 weeks. The
1. CT scan of normal pancreas in patient with clinical pan-
creatitis (grade A).
2. Diffuse enlargement of the pancreas without peripan-
creatic inflammatory changes (grade B).
3. Enlarged pancreas associated with haziness and in-
creased density of peripancreatic fat (grade C). Note
presence of diffuse fatty infiltration of liver.
I
4
8.
I
.#,
A
RESULTS
Of the 83 patients surveyed, 63 me-
covered with medical treatment alone
and were discharged, while 18 pa-
tients (21.7%) became septic and me-
Figures 1, 2, and 3
768 #{149}Radiology September 1985
initial examinations were performed
within the first 3 hospital days in 40 pa-
tients and between day 4 and 10 in 43 pa-
tients. In general, severely ill patients me-
ceived priority for CT examination,
making this sample unrepresentative of
all patients with acute pancreatitis ad-
mitted to our institution.
CT scans were interpreted without prior
knowledge of clinical findings or objec-
tive prognostic signs. The following con-
ditions were specifically looked for and
recorded: presence of fatty liver, gallblad-
den pathology, peritoneal effusion, and
pleural effusions.
In addition, we classified the type of
pancreatic inflammation seen on CT scans
into five categories. This classification was
based on an overall assessment of size,
contour, and density of the gland and per-
ipancreatic abnormalities. Specific mea-
surements were not used in this assess-
ment. We used the following grades,
which are similar to those reported in the
literature (8): grade A, normal pancreas
(Fig. 1); grade B, focal or diffuse enlarge-
ment of the pancreas (Fig. 2) (including
contour irregularities, nonhomogeneous
attenuation of the gland, dilatation of the
pancreatic duct, and foci of small fluid col-
lections within the gland, as long as there
was no evidence of peripancreatic dis-
ease); grade C, intrinsic pancreatic abnor-
malities associated with haziness and
streaky densities representing inflamma-
tory changes in the peripancreatic fat (Fig.
3); grade D, single, ill-defined fluid collec-
tion (phlegmon) (Fig. 4); grade E, two or
multiple, poorly defined fluid collections
2.
(Fig. 5) or presence of gas in or adjacent to
the pancreas (Fig. 6).
quired surgical drainage of abscesses.
One patient underwent surgery to me-
move a persistent pseudocyst. Five
patients with abscesses died, and one
other patient died of hepatic and
renal failure without evidence of pan-
creatic abscess. The relationship of
the objective prognostic signs to the
clinical course is shown in Table 2.
4
“I
4,
4
A
Figure 4
Volume 156 Number 3 Radiology #{149}769
a. b.
CT scan of enlarged body and tail of the pancreas (a) with associated fluid collection in left anterior pararenal space (b) (arrows) (grade D).
r Figure 5
� a. b.CT scan showing large fluid collections in the lesser sac and anterior pararenal space in patient with grade E pancreatitis. Note compression
. with partial obstruction of the duodenum and slight thickening of gallbladder wall (arrows).
Secondary CT Findings
Secondary CT findings that may
correlate with the severity of acute
pancreatitis were recorded. We ob-
served fatty infiltration of the liver in
21 patients (25.3%) (Fig. 3) from all
five grades of pancreatitis. Gallstones
were seen on CT scans in 12 patients
(14.5%), but were missed in a number
of other patients who proved to have
cholelithiasis on sonognams or during
surgical exploration. We observed
gallbladdens with thickened walls in
five patients, none of whom had gall-
stone pancreatitis (Fig. 5). Six patients(7.2%) had free fluid in the pemitoneal
cavity, five with grade D or E pancrea-
titis. We detected pleural effusions in
27 patients (32.5%). Effusions were
present in 41% of the 12 patients with
grade D and 65% of the 23 patients
with grade E pancreatitis. Bilateral ef-
fusions were seen in 22% of patients
with grade E pancreatitis.
In our morphologic evaluation, we
noted a diffuse involvement of the
pancreas in 68 of 83 cases and a seg-
mental distribution in the remaining
15 cases (18.1%). In nine patients
.�.
44
4
a. CT scan showing increased density of the peripancreatic retroperitoneal fat associated with extraluminal air (arrow) in patient with
pemipancreatic abscess.b. Bilateral, ill-defined, retroperitoneal fluid collections with multiple gas bubbles in patient with abscess (grade E).
4
I-
I
.4
r
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I
.I�
A
Figure 6
770 #{149}Radiology September 1985
(10.8%), the inflammatory process in-
volved exclusively or predominantly
the head of the pancreas (Fig. 7); in
five, the body and tail; and in one,
only the tail of the pancreas. Swelling
of only the head of the pancreas was
present in three of the 1 1 patients
with gallstone pancreatitis (27.3%)
but in only six cases of all other types
of pancreatitis (8.3%). Two patients
with histories of previous pancreatitis
had pancreatic ductal calcifications
demonstrated on CT scans.
The patients were divided accord-
ing to the five grades, and the mela-
tionships between different grades
and the clinical course and prognosticsigns were analyzed. There were 12
patients (14.5%) in grade A, 19 (22.9%)
in grade B, 17 (20.5%) in grade C, 12
(14.5%) in grade D, and 23 (27.7%) in
grade E.
CT and Clinical Course
The relationship between early CT
findings and clinical course is sum-manized in Table 3. The average num-
ben of fasting days (nothing by
mouth) and days in the hospital come-
lated roughly with the severity of the
initial CT findings. Exceptions to the
general trend, however, occurred,
with some patients in grade B requir-
ing 4 weeks of hospitalization and
some in grade D requiring less than 2
weeks of treatment. No patient with
grade A pancreatitis was seriously ill,
and all five patients who died becauseof local complications (abscesses) mi-tially had grade D or E pancmeatitis.
Retropemitoneal, extraluminal air
was seen in four patients (Fig. 5) who
all proved at surgery to have infected
abscesses. In three cases, gas bubbles
were detected on CT scans in patients
with only one to three prognostic
signs within the first 24 hours of hos-
pitalization.
Fluid collections were initially seen
in 35 patients in grades D and E (or
45.7% of these combined grades). Fol-
low-up CT scans showed that in 19
patients (54.3%), fluid collections me-
solved without further complications,
while in 16 patients (45.7%), they did
not and eventually became infected.
Fluid collections developed in only
three patients who did not have them
initially and were classified as grade
C pancreatitis. One of these patients
ended up with a pseudocyst and two
with abscesses. In 15 patients, the in-
fected fluid collections were drained
between the 5th and 50th day hospi-
talized after an average stay of 25
days.
CT and Prognostic Signs
The relationship between early CTfindings and prognostic signs is
shown in Table 4. The relationship
between the number of prognostic
Figure 7
Volume 156 Number 3 Radiology . 771
signs and grades of pancreatitis varies
.� widely in patients with zero to five
prognostic signs. All patients with
more than five prognostic signs were
in grade E; however, a few patients
�pa with four and five signs were in
grades A and B.
When the number of patients with
�r abscesses or those that died were ana-lyzed as a function of combined CT
findings and prognostic signs (Table
5), the complication rate and progno-
sis could be better assessed. The num-
., ben of patients with abscesses in
grades C and D is significantly larger
if the number of prognostic signs is
higher. In addition, the percentage of
deaths correlated well with the num-
bem of prognostic signs.
DISCUSSIONThe radiologic features and role of
.� -. CT scanning in initial diagnosis of
acute pancreatitis and its complica-
tions are well established in the lit-
�- erature (8-18). The CT appearance of
clinical forms of mild (edematous, in-
terstitial) or severe (necrotizing, hem-
omnhagic) pancreatitis has been de-p scnibed (8, 19, 20). To our knowledge,
however, a comprehensive evalua-
tion of the prognostic value of the mi-.3 tial CT examination based on clinical
follow-up, surgical findings, and con-
S relation with prognostic signs has not
been performed. This study attempts
to fill this gap and establishes the val-
ue of CT scanning, not only in the
initial diagnosis of pancreatitis, but as
a prognostic indicator of the disease’s
severity and its expected complica-
tions.
Secondary CT Findings
Our search of the literature did not
disclose a previous assessment of the
secondary CT findings evaluated in
this study. Fatty infiltration of the liv-
en was seen in 21% of our patients
(Fig. 3) and occurred about equally in
patients with mild, moderate, or se-
vene pancreatitis. Gallbladders with
thickened walls were seen in five
cases (Fig. 5), and the significance is
unknown since the condition was
present in patients without clinical
evidence of cholecystitis. It may me-
present nonspecific edema associated
with alcoholic liver disease or non-
specific inflammation related to pan-
creatitis. Pleural effusions were larger
and more commonly seen in patients
with severe pancreatitis. In this series,
they were present in 65% of grade E
patients and in only 10% in grades A
and B. Bilateral pleural effusions were
seen almost exclusively in grade E pa-
tients. There was no correlation be-
tween the severity of pancreatitis and
its cause in this series. Five of the 11
cases of gallstone pancreatitis were
classified as grade E, while the other
six were grade A, B, or C.While acute pancreatitis is general-
ly considered a diffuse disease, in this
series a segmental form of pancreati-
tis was observed in 18.1% of the cases.
(Fig. 7). Specifically, the head of the
pancreas was enlarged in a larger pro-
portion of patients with gallstone
pancreatitis (27.3%), compared with
the proportion of the total series
(8.3%).
CT and Clinical Course
The survey of the statistical data
presented shows that a clear comrela-
tion can be established between the
severity of pancreatitis, as determined
at the initial CT examination, and the
clinical course. We noted a steady
trend toward an increased average
number of fasting days and days hos-
pitalized in patients with more severe
grades of pancreatitis (Table 3). Five
of six deaths and 88.8% of all abscesses
occurred in patients initially classi-
fied as having grades D and E pan-
creatitis. No patients originally classi-
fied as having grade A or B pan-
creatitis had subsequent abscesses. All
patients with a normal pancreas on
CT scan (grade A) had a mild clinical
course without complications and
were discharged in less than 2 weeks.
Although the clinical course was
consistent with the grade of pancrea-
titis, some grade A patients may not
have had pancreatitis at all. There-
fore, the exact percentage of patients
with acute pancreatitis and a normal
CT scan is difficult to assess. This per-
centage depends mainly on the sever-
ity of acute pancreatitis and the time
of the examination and should be ex-
pected to vary from series to series.
CT and Development ofAbscesses
A strong relationship exists be-
tween the initial presence of pemipan-
creatic fluid collections (grades D and
E) and the development of abscesses.
Abscesses occurred in 18 patients in
this series (21 .7%), but they developed
in only two patients without initial
fluid collections.
The presence of poorly encapsulat-
ed pemipancneatic fluid collections in
patients with acute pancreatitis
.4
4
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4
A
772 . Radiology September 1985
should not be regarded casually. Flu-
id collections resolved spontaneously
in 54.3% of patients who had them but
lingered on and eventually became
infected in the remaining 45.7%. Fol-
low-up CT examinations should be
performed in these patients to assess
the presence, size, and location of
these collections until they resolve.
Previously, extravasated pancreatic
secretions and the development of
large pemipancreatic fluid collections
were considered an escape mecha-
nism, leading to a beneficial decom-
pression of the pancreatic duct system
(12). In our study, however, based on
short-term CT and clinical follow-up
evaluation, we failed to detect any ad-
vantages of large fluid collections for
this group of patients. While we did
not conduct long-term evaluations,
we found that extravasated fluid was
associated with a protracted and se-
vene clinical course. In patients with-
out such fluid, the course of pancrea-
titis was mild or significantly shorten
and less complicated.
The diagnosis of abscess in most of
our cases was based on the presence
of a persistent fluid collection plus
sepsis unresponsive to antibiotic them-
apy. Because of debris and necrotic
tissue, the density of fluid collections
was variable (5-30 HU) and not help-
ful in this diagnosis. The roles of per-
cutaneous aspiration and drainage of
pancreatic abscesses have been me-
ported in the literature (21, 22), but
these procedures were not used in
this series.
Retmopemitoneal air was seen in four
patients, all of whom had proved ab-
scesses at surgery. As reported in the
literature (23, 24), fluid collections
containing air may develop secon-
damy to entemic fistulas and may not
always indicate an abscess. However,
this CT finding, particularly when
seen during the initial attack, strong-
ly suggests a gas-forming infection
and is extremely valuable in quickly
identifying this potentially life-
threatening complication. In three
patients, metropemitoneal aim visual-
ized on CT scan in the first 24 hours
led to a correct diagnosis that was not
suspected clinically. Surgery was per-
formed without delay, and all three
patients survived.
Prognostic Signs, CT, andClinical Course
The relationship between prognos-
tic signs and severity of pancreatitis is
documented in Table 2. Infected ab-
scesses occurred with an increased in-
cidence in patients with several prog-
nostic signs. Abscesses were seen in
80.0% of patients with six to eight
signs, compared with 12.5% of pa-
tients with zero to two signs. We
found that using prognostic signs and
CT findings led to a better estimation
of the risk of death in this series. In
grades A and B patients, none of the
patients died, regardless of the num-
ben of prognostic signs, which varied
between zero and five. On the other
hand, the mortality of patients initial-
ly classified as grades C, D, on E come-
lated with the increasing number of
prognostic signs (Table 5).
We conclude that initial CT exami-
nation in cases of acute pancreatitis is
very helpful in establishing on con-
firming the clinical diagnosis, as well
as in depicting associated abnonmali-
ties. CT can also be used as an early
indicator of the disease’s severity and
its expected morbidity and mortality.
We found a good correlation between
the grades of mild, moderate, or se-
vene pancreatitis as established by CT
appearance and the clinical course,
development of abscesses, and death.
The use of objective prognostic signs
with initial CT findings improves the
original prognostic estimation and
identifies patients in whom life-
threatening complications may devel-
op. CT examinations should be pen-formed in all patients with moderate
or severe clinical forms of pancreatitis
to evaluate the presence and severity
of the initial attack and to assess its
clinical evolution. U
Send correspondence and reprint requests to:Emil Balthazar, M.D., NYU Medical Center, Bel-levue Hospital, Department of Radiology, 27thStreet and 1st Avenue, New York, New York10016.
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