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CT of the Stomach:
Spectrum of Disease1
Elliot K Fishman, MD
Bruce A. Urban, MD
Ralph H. Hruban, MD
In evaluation of gastric disease, computed tomography (CT) has proved
to be a valuable adjunct to barium studies and endoscopy. CT clearly
demonstrates the primary pathologic condition and shows extension of
disease to adjacent or distant structures. Useful in staging gastric cancer,
CT has also proved valuable in detecting and defining the extent of other
gastric neoplasms such as lymphoma, leiomyosarcoma, and metastasis to
the stomach. Recent advances in CT technology such as spiral CT-
coupled with air contrast gastric studies and a better understanding of
the need to optimize CT protocols-suggest that the value of CT in these
applications will increase. CT has also been shown to be valuable in de-
tection and differentiation of other gastric conditions such as benign tu-
mors, Helicobacterpylori and other infections, various forms of gastritis
(radiation, eosinophilic, and emphysematous), ulcer disease, M#{233}n#{233}trier
disease, and varices. Adequate gastric distention is essential for success-
ful gastric CT.
. INTRODUCTION
The stomach is involved by a spectrum of pathologic processes that range from in-
flammatory and infectious disease to benign and malignant tumors. The clinical mani-
festations of gastric disease vary from severe abdominal pain in the right upper re-
gion and acute abdomen to vague symptoms such as weight boss and anemia. In
most cases, computed tomography (CT) is requested to better demonstrate a patho-
logic process seen or suggested by other means (eg, an upper gastrointestinal radio-
graphic series or endoscopy) or suspected on the basis of the clinical manifestations.
In other cases, gastric disease is first noted on the CT scan and may never have been
considered in the differential diagnosis before the CT examination (1).
In this article, we present the wide range of gastric pathologic processes as seen
on CT scans. These gastric processes include malignant tumors, benign tumors, in-
flammatory disease, and miscellaneous disease processes. Emphasis is placed on CT
signs and criteria for helping distinguish between the various entities. The role of CT
in management of gastric disease is also addressed.
Index terms: Gastritis, 72.291 . Peptic ulcer, 72.25 #{149}
Stomach, CT, 72.1211 Stomach,
#{149} diseases, 72.292 Stomach,
#{149}
infection, 2.2O Stomach.
#{149} neoplasms. 72.30 Stomach,
#{149} varices, 72.75
RadioGraphics 1996; 16: 1035-1054
I From the Russell H. Morgan Department of Radiology and Radiological Science (E.K.F.. B.A.FJ.) and the Department of
Pathology (R.H.H.). Thejohns Hopkins Medical Institutions, Baltimore. Md. Presented as a scientific exhibit at the 1995
RSNA scientific assembly. Received February 28. 1996; revision requested April 2 and received April 30; accepted May 6.
Address reprint requests to E.K.F., Department of Radiology, The Johns Hopkins Hospital, 600 N Wolfe St. Baltimore,
MI) 21287.
, RSNA, 1996
1035
. TECHNIQUE OF GASTRIC CT
Table 1
The key to the detection and staging of gastric
Scanning Protocols for astric CT
disease is a carefully performed CT examina-
tion of the stomach and the classic sites of Model of CT Scanner
Scanning Parameter Plus Plus-S
spread of disease, including local lymph node
chains and the liver. The examination must in- Acquisition time (see) 24 32
dude gastric distention (with positive or nega- Kilovolt peak (kVp) 1 20 120
tive contrast material) and use of iodinated, in- Milliampere seconds (mAs) 2 10 210
travenously administered contrast material. Section thickness (mm) 5 or 8 4 or 5
Protocols for gastric CT are optimized to avoid Table speed (mm/see) 5 or 8 4 or 5
Pitch 1 1.0-1.6
false-negative or false-positive results. In the
Data reconstruction (mm) 3 or 4 3 or 4
past, such protocols were developed specifi-
cally for dynamic CT; however, all currently
recommended protocols are specifically for spi-
rab (helical) CT. Several commonly used gastric . Pitfalls
CT protocols are listed below (2-4). The maximum thickness of the normal gastric
wall at CT is typically 7-10 mm. if the stom-
. Protocols for Contrast Material Ad- ach is not satisfactorily distended, the gastric
ministration wall may appear thickened, which is sugges-
tive of disease. This potential pitfall is most
Protocol 1. -The orally administered contrast common in the gastric fundus and antrum. If
material is 750 mL of a flavored 3% solution of care is not taken, this pitfall could bead to false-
diatrizoate sodium meglumine (Hypaque; Nyco- positive or false-negative CT results. Therefore,
med, Princeton, NJ) given in split doses over if there is any doubt about the adequacy of
30-45 minutes. The last dose (250 mL) is given gastric distention after the initial scans are oh-
immediately before the patient is placed in the tamed, additional oral contrast material should
scanning gantry. The intravenous contrast mate- be given and several delayed scans should be
rial is 100-1 10 mL of iohexol (Omnipaque-3S0; obtained. Some articles have suggested obtain-
Nycomed) injected at a rate of 2-3 mL/sec. ing prone or lateral decubitus views as an ad-
Scanning typically begins approximately SO sec- junct to the standard CT study, but obtaining
onds after the initiation of contrast material in- such views is usually not necessary and is not
jection. part of our standard imaging protocol.
if tumor staging with gastric CT results in
Protocol 2. -The oral contrast material is understaging, possible sources of error include
1 ,000 mL of water given in split doses over inability to detect adjacent organ invasion, tu-
15-30 minutes. The last dose (250 mL) is mor infiltration of normal-sized lymph nodes,
given immediately before the patient is placed peritoneab carcinomatosis, and liver metastasis.
in the scanning gantry. The intravenous con- If tumor staging with gastric CT results in
trast material is the same as in protocol 1. overstaging, the most likely sources of error in-
dude enlarged nodes without tumor and ap-
Protocol 3. -The oral contrast material is 4-6 parent invasion of adjacent organs.
g of effervescent citrocarbonate granules taken
with 30 mL of water immediately before scan- . CT OF MAUGNANT GASTRIC TU-
ning. The intravenous contrast material is the MORS
same as in protocols 1 and 2. Worldwide, gastric cancer accounts for nearly
half a million deaths each year. In the United
. Scanning Protocols States, gastric cancer is responsible for more
The exact scanning protocol depends on the than 13,000 deaths and 24,000 new cancer
model of the CT scanner and the available spi- cases per year. The age-adjusted death rate
ral acquisition time (24-40 seconds). Typical varies from 5.3 deaths per 100,000 males in
protocols for our current equipment (Somatom the United States to 54.6 deaths per 100,000
Plus and Plus-S scanners; Siemens Medical Sys- males in South Korea (5,6).
tems, Iselin, NJ) are shown in Table 1. Gastric cancer occurs twice as frequently in
males as in females. Reported risk factors in-
dude smoking and dietary factors such as ni-
trates, nitrites, and pickled vegetables. The
clinical manifestations depend on lesion boca-
1036 U Scientific Exhibit Volume 16 Number 5
Figure 1. Diagrams show the four stages of gastric cancer according to a CT-based staging system (10). The in-
set diagrams show a cross section of the gastric wall at the tumor site. Small lymph nodes are seen along the
lesser curvature of the stomach; normal-sized nodes are depicted as grayish white. The liver is outlined but is de-
picted as transparent. (a) A stage I tumor (arrow) is an intraluminal mass that invades the mucosa (in) without
tumor spread. (b) A stage II tumor (arrow) is associated with a wall thickness of greater than 1 cm and invades
through the submucosa into the muscularis propria (nip). (c) A stage III tumor (arrow) invades the muscularis
propria and serosa (s). Enlarged nodes (depicted as reddish white) are also seen in the nodal chain. (d) A stage
IV tumor (straight arrow) demonstrates extension through the serosa into the peritoneal cavity. Enlarged lymph
nodes and liver metastasis (curved arrow) are seen.
tion and size and include gastrointestinal niques used, which included slow delivery of
bleeding, abdominal pain, and weight boss. contrast material, slow data acquisition, and
There are numerous articles on the accuracy of lack of spiral CT data sets. Many of the corn-
CT in detecting gastric cancer. An article by monly quoted articles were published in the
Minami et al (7) is representative of the usual late 1970s and early 1980s (8,9). Habvorsen
results. They found that in 71 patients who and Thompson (10) developed a CT-based
underwent surgery, the detectability of early staging system for gastric cancer, which is il-
and advanced gastric cancers and the accuracy lustrated in Figure 1 . A modification of this sys-
of classification of gross appearance and sero- tem is shown in Table 2.
sal invasion as determined with CT were 53%, There has recently been renewed interest in
92%, 80%, and 80%, respectively. increasing the accuracy of CT in the detection
The published results on the accuracy of CT and staging of gastric cancer. Cho et al (11)
in staging gastric cancer have generally been used a protocol of gastric distention with wa-
somewhat disappointing. However, careful
analysis of these results suggests that they
were largely related to the scanning tech-
September 1996 Fishman et al U RadloGraphics U 1037
Table 2
System for CT Staging of Gastric Cancer
Stage Description
I Intraluminal mass
II Intraluminal mass and gastric wall
thickness > 1 cm
III Direct tumor involvement of adjacent
structures (including lymph nodes)
N Distant metastasis
Note-This system is a modification of the stag-
ing system of Halvorsen and Thompson (10).
ter (600-800 mL), rapid intravenous injection
of contrast material (150 mL of nonionic con- Figure 2. Stage II gastric adenocarcinoma in a 57-
trast material injected at a rate of S mL/sec for year-old woman with epigastric distress. CT scan
30 seconds), and two-phase image acquisition shows a polypoid gastric mass (arrow) without cvi-
(30 seconds for the early phase and 2 minutes dence ofextension beyond the stomach. No evidence
of metastasis is seen.
for the equilibrium phase). In a study of 52 pa-
tients with pathologically proved gastric can-
cer, 41 had moderate to marked heteroge-
neous lesion enhancement in the early phase using dual-phase spiral CT with narrow colli-
and homogeneous lesion enhancement in the mation and close interscan spacing (ie, 4-mm-
equilibrium phase. These enhancement pat- thick sections reconstructed at 3-mm intervals)
terns correlate with the classic angiographic to determine if this protocol could further in-
appearance of gastric cancer: neovascularity in crease the accuracy of CT. Such a protocol
the arterial and capillary phases and tumor would surely increase the accuracy of liver me-
staining in the venous phase. The primary tu- tastasis detection, which is often a key compo-
mor was detected in five of nine cases of early nent in the staging of gastric cancer.
gastric cancer and 4 1 of 43 cases of advanced
gastric cancer. The overall detection rate was . Adenocarcinoma
88%. When correlated with results of TNM Adenocarcinoma is the most common primary
staging, CT was 65% accurate in determining gastric tumor; approximately 95% of primary
depth of tumor invasion, 83% accurate in de- gastric neoplasms are adenocarcinomas. It is
termining degree of serosal invasion, and 70% often fatal, with a 5-year survival rate of ap-
accurate in demonstrating regional lymph proximately 20%. Adenocarcinoma can be clas-
node metastasis. sified into four types: papillary, tubular, muci-
These authors’ results are interesting be- nous, and signet-ring cell.
cause their study was performed with dynamic The CT appearance is variable. Common
CT (single scans acquired nearby every S sec- appearances include the following (1 2- 1 4): a
onds), generally with 10-mm-thick sections. It focal lesion with wall thickening (Fig 2), dif-
would be interesting to duplicate their study by fuse infiltration (linitis plastica) (Figs 3, a 4),
bulky mass with ulceration (Fig 5), and a
bulky tumor that simulates lymphoma or sar-
coma (Fig 6).
1038 U Scientific Exhibit Volume 16 Number 5
3a. 3b.
4a. 4b.
Figures 3, 4. (3) Stage III gastric adenocarcinoma in a 47-year-old woman with a history of persistent post-
prandial emesis and abdominal discomfort. Spiral CT scans show infiltration of the stomach by tumor. Several cc-
liac nodes are present (arrow). (4) Stage IV gastric adenocarcinoma in a 76-year-old man with a history of gen-
eral malaise and loss of appetite. (a) CT scan shows infiltration of the stomach with a linitis plastica-type ap-
pearance. (b) CT scan at the level of the umbilicus shows carcinomatosis with implants on the greater omentum
(arrows).
a. b.
Figure 5. Stage IV gastric adenocarcinoma in a 62-year-old woman with weight boss and abdominal pain. Spi-
ral CT scans show a large, ulcerating gastric tumor with spread beyond the gastric wall. There is evidence of ad-
enopathy in the cebiac nodal chain (arrow).
September 1996 Fishman et al U RadioGraphics U 1039
Figure 6. Stage IV gastric adenocarcinoma in a 67-
year-old man with a history of abdominal pain and Figure 7. Recurrent stage N gastric adenocarci-
gastrointestinal bleeding. Spiral CT scan shows a norna in a 59-year-old man with nausea and vomiting
barge, ulcerating, exophytic gastric mass with liver who had undergone partial gastrectomy for gastric
metastases. The mass appears to involve the pan- adenocarcinoma. Spiral CT scan shows recurrent gas-
creas. tric adenocarcinoma (arrow) with adenopathy and
liver metastases.
Nodal spread of disease may extend into or and solid ovarian mass that is usually indistin-
around the region of the gastrohepatic biga- guishabbe from a primary ovarian tumor. Kim
ment (Fig 7). Nodes in this region are consid- Ct al (18) reported a case of gastric metastasis
ered positive if they are 8 mm or greater in di- to the uterus and reviewed the literature; they
ameter ( 1 5). Tumor spread to these nodes may found that such metastasis is more common in
also occur in breast cancer, esophageal can- younger women. The most common sites of
cer, and lymphoma. CT is especially useful in origin for uterine metastasis are gastric and
detecting unsuspected or distal sites of tumor breast cancer.
spread including the liver, pelvis, and ovaries CT may be helpful in determining spread to
(Figs 8, 9). adjacent organs like the pancreas and spleen.
Pelvic metastases may take the form of drop However, detection of extension may be diffi-
metastases on the sigmoid colon or rectum, cult. Sussman et al (13) evaluated 75 patients
metastasis to the ovaries (Krukenberg tumor), with gastric cancer and found that 47% were
or (rarely) metastasis to the uterus (16-18). incorrectly staged with CT; 3 1 % were under-
Krukenberg tumor may be unilateral or bilat- staged, and 16% were overstaged. The most
eral and has a diameter of 1 -20 cm (Fig 8). problematic aspects of staging were accurately
The classic CT appearance is a mixed cystic detecting adenopathy and determining pancre-
atic invasion. It is difficult to detect invasion be-
cause of the intimate relationships of these
structures. However, the poor results of this
1040 U Scientific Exhibit Volume 16 Number 5
8. 9.
Figures 8, 9. (8) Stage N gastric adenocarcinoma with metastasis to the ovaries after one course of chemo-
therapy in a 61-year-old woman with known metastatic gastric cancer. Spiral CT scan shows large, complex, cys-
tic and solid pelvic masses compatible with Krukenberg tumors involving the ovaries. This diagnosis was proved
at percutaneous biopsy. (9) Stage IV gastric adenocarcinoma with metastasis to the ribs in a 55-year-old man
with a history of gastric cancer and increasing right rib pain. Spiral CT scan shows a large, destructive lesion
that involves the ribs, consistent with metastasis.
study may be largely due to the fact that the An unusual appearance of primary adeno-
data were collected from 1980 to 1986. Today, carcinoma of the stomach is mucinous carci-
spiral technology and better image resolution noma, which may partly calcify (20,21). The
may help one avoid these problems. calcifications have been described as nodular,
One variant of adenocarcinoma consists of miliary, or punctate and may be hornoge-
large tumor masses 5-14 cm in diameter neously distributed. A gastric mass that partly
(mean, 9 cm) and tumor growth with a large calcifies is more typically a leiomyoma or (less
extraluminab component (19). This type of tu- frequently) a leiomyosarcoma.
mor, known as exophytic adenocarcinoma, CT is also valuable for follow-up after gastric
may arise in any portion of the stomach but is surgery such as partial or total gastrectomy
most commonly seen in the body and antrum. (22,23) (Fig 7). Common sites of recurrence
The appearance is usually similar to that of include the liver, local nodal groups such as
gastric beiomyosarcoma. According to Lee et al the gastrohepatic nodes, and the gastrectomy
(19), thickening of the gastric wall adjacent to bed. All can be well defined with CT. Compli-
the exogastric mass is typical of exophytic ad- cations of partial or total gastric resection such
enocarcinoma and allows distinction from gas- as ulceration, perforation, and obstruction can
tric beiomyosarcoma. However, our experience be detected with CT.
with this sign has been variable. In most
cases, differentiation is of little importance be-
cause endoscopy with biopsy will invariably be
performed.
September 1996 Fishman et al U RadioGraphics U 1041
Figures 10, 11. (10) Biopsy-proved gastric lym-
phoma in a 74-year-old woman with abdominal pain
and gastrointestinal bleeding. Spiral CT scan shows
marked thickening of the gastric folds that extends up
to the esophagogastric junction. Ulceration in the gas-
tric fundus is also seen. (11) Biopsy-proved large cell
gastric lymphoma in a 62-year-old woman with ab-
dominal pain and fullness in the left upper quadrant.
CT scans show gastric fold thickening, extensive ad-
enopathy in the porta hepatis and paraaortic zones,
and splenomegaby.
. Lymphoma
The stomach is the most frequent site of lym-
phomatous involvement of the gastrointestinal
tract; such involvement makes up approxi-
mately 3% of gastric tumors (24,25). Non-
Hodgkin lymphoma accounts for approxi-
mateby 80% of cases of gastric lymphoma.
Lymphoma has a variety of appearances such
as a polypoid form, an ulcerating form, and a
combination of these forms. if evaluation is
based strictly on CT criteria, lymphoma may
sometimes be indistinguishable from adenocar-
cinoma.
Gastric bymphoma is characterized by thick-
ening of the stomach wall (Fig 10). In a re-
view of 23 patients with gastric lymphoma,
Megibow (26) found an average wall thickness
of 5 cm (range, 2.5-8 cm). Buy and Moss (27)
found an average wall thickness of 4 cm in
their series of 1 2 patients. The CT patterns of .. ‘. 1 .
. --.,
gastric involvement are (a) diffuse infiltration
that involves more than 50% of the length of Figure 12. Gastric lymphoma in a 72-year-41d man
the stomach (Fig 1 1), (b) segmental infiltration who underwent CT for staging of lyniphoma. CT
of the stomach, and (c) a localized pobypoid scan shows marked thickening of the gastric folds
with extensive adenopathy and ascites. Extensive dis-
form often associated with an ulcer and occa-
ease was also present in the mesentery and small
sionally with perforation.
bowel.
Tumor infiltration is usually homogeneous
on cross-sectional images, although regions of
low attenuation may be seen (Fig 1 2). Most
patients with gastric bymphoma have associ-
ated adenopathy. One of the key points in dii-
1042 U Scientific Exhibit Volume 16 Number 5
14a. 14b.
Figures 13, 14. (13) Gastric beiomyosarcoma in a 70-year-old man with abdominal pain and left upper quad-
rant fullness. CT scans show a mass larger than 20 cm in diameter that invades the spleen and left kidney. The tu-
mor extends downward to invade the left psoas muscle as well. (14) Gastric beiomyosarcoma in a 64-year-old
man with gastrointestinal bleeding who underwent endoscopic biopsy of the tumor. CT scans show the tumor
arising from the posterior gastric wall. The patient also developed metastasis to the left iliac crest.
ferential diagnosis of gastric lymphoma and gastric leiomyosarcoma appears as barge (aver-
adenocarcinoma is that in bymphoma the age diameter, 1 5 cm), spherical or ellipsoid
nodes are usually bulkier and extend beneath masses that are best described as exogastric
the renal hilum. Another key differential diag- (Fig 1 3). The tumors are often necrotic, a fea-
nostic point is the difference in wall thickness ture that is highlighted if iodinated, intravenous
between adenocarcinoma (usually 1 -3 cm) contrast material is used. They may ulcerate
and lymphoma (average, 5 cm). Patterns of and occasionally may perforate.
contrast enhancement have not been reliable Gastric leiomyosarcoma may invade adja-
in our experience. Gastric involvement with cent organs like the spleen or pancreas. Meta-
bulky tumor masses is not uncommon in static spread to the liver may be seen; cystic or
American Burkitt lymphoma. Gastric bym- necrotic metastasis is common. Tumor spread
phoma has a better prognosis than gastric ad- may also involve a portion of the peritoneal
enocarcinoma. cavity. The pattern of spread of leiomyosar-
coma is similar regardless of the site of origin
. Leiomyosarcoma (ie, stomach, uterus, small bowel, or muscle)
Gastric leiomyosarcoma is an unusual tumor of (Fig 14).
smooth muscle origin that represents 1%-3.5%
of gastric malignancies (28-30). Approximately
two-thirds of smooth muscle tumors of the gas-
trointestinal tract arise in the stomach. At CT,
September 1996 Fishman et al U RadioGraphics U 1043
15a. 15b.
Figures 15, 16. (15) Gastric beiomyosarcoma in a
79-year-old woman with a &month history of back
and beg pain. Spiral CT scans show an exogastric
mass with heterogeneous enhancement. The mass cx-
tends posteriorly and downward to invade the spbenic
vessels and tail of the pancreas. (16) Gastric leiomyo-
sarcoma in a 69-year-old man with a history of gas-
trointestinal bleeding. CT scan shows a large exogas-
tric mass that arises near the gastric fundus. Minimal
ulceration is present in the tumor.
Distinction between beiomyoma and beio-
myosarcoma is usually possible on the basis of
lesion diameter (usually 1 0 cm for beiomyosar-
coma), location, and tumor necrosis (Figs 15,
16). However, in select cases leiomyoma may
appear aggressive and be indistinguishable from
sarcoma solely on the basis of CT criteria. Leio-
myosarcoma may calcify, but in our experience
this is rare.
. Liposarcoma
Other types of sarcoma may also involve the
stomach. The second most common type is li-
posarcoma (3 1). This tumor is rare and may
look nearly identical to a leiomyosarcoma if fat
is not definable on the CT scan. Liposarcoma
is usually very aggressive.
. Metastasis
Metastasis to the stomach (Fig 1 7) occurs in
less than 2% of patients who die of cancer.
Spread to the stomach may be hematogenous
Figure 21. Adenocarcinoma ofthe colon metastatic
(eg, malignant melanoma or breast cancer)
to the stomach in a 51-year-old man with a history of
(Fig 18), by direct extension (eg, pancreatic
metastatic colon cancer. CT scan shows tumor im-
cancer or hepatoma) (Figs 19, 20), or by bym-
plants on the gastric antrum (arrow).
phatic spread (eg, esophageal or colon can-
cer) (Fig 21) (32-34). Metastatic disease varies
in appearance from bulb’s-eye-type lesions in cancer. In select cases, the appearances of a
melanoma to a linitis plastica pattern in breast primary gastric cancer and metastatic disease
can he identical. To make the correct diagno-
sis, careful attention must be paid to the clini-
cab history.
1044 U Scientific Exhibit Volume 16 Number 5
17. 18.
Figures 17-19. (17) Biopsy-proved metastatic ova-
rian cancer in a 63-year-old woman with a history of
ovarian cancer. Follow-up CT scan obtained after die-
motherapy shows implants on the gastric antrum. The
resultant narrowing of the antrum caused delayed gas-
tric emptying. (18) Melanoma metastatic to the stom-
ach in a 5 1-year-old man with a history of malignant
melanoma. CT scan shows a 1 .5-cm-diameter ulcerat-
ing metastasis to the gastric wall (arrow). (19) Pan-
creatic cancer with direct extension into the stomach
in a 60-year-old man with a history of pancreatic ad-
enocarcinoma. CT scan shows direct tumor extension
into the gastric body and antrum with tumor infiltra-
tion (arrow).
19.
Figure 20. Adenocarcinoma of the transverse colon invading the stomach in a 73-year-old woman with guaiac-
positive stools and bad breath. Spiral CT scans show a large, ulcerating mass in the left upper quadrant. The
mass is most suggestive of an ulcerating gastric leiomyosarcoma. At resection, the mass was found to be a tumor
of the distal transverse colon that invaded the stomach by means of a gastrocolic fistula.
September 1996 Fishinan et al U RadloGraphics U 1045
23L 23b.
Figures 22, 23. (22) Gastric beiomyoma in a 72-year-old man with a history of vomiting bright red blood fob-
bowed by dizziness and fatigue. (a) Spiral CT scan shows a smooth, ulcerating mass in the gastric fundus. (b) Re-
constructed view shows that the mass is submucosal (arrow), consistent with beiomyoma. At resection, the mass
was found to be a leiomyoma. (23) Gastric leiomyoma in a 57-year-old man with a 2-year history of abnormal re-
suits on liver function tests. CT scans show a mass that arises from the posterior gastric wall (arrows) and con-
tains areas of necrosis; it was suspicious for a malignancy. At resection, the mass was found to be a leiomyoma.
S CT OF BENIGN GASTRIC TUMORS may ulcerate or perforate (Fig 22). Exogastric
leiomyoma may be difficult to distinguish from
. Lelomyoma a malignant process (Fig 23). Both beiomyoma
Gastric leiomyoma is the benign counterpart of and beiomyosarcoma occasionally enhance af-
malignant leiomyosarcoma and is the most ter injection of iodinated contrast agents (up to
common benign gastric tumor (35,36). It ac- 1 .5 times baseline) or calcify.
counts for approximately 2.5% of all gastric tu-
mors. The lesions are usually submucosal but . Lipoma
may be exogastric in select cases. Leiomyoma Lipoma is a rare gastric tumor that is usually
varies in diameter (usually <5 cm) and is usu- detected as an incidental fmding. The lesions
ally asymptomatic, although in some cases it are of variable fat attenuation and are often
smooth walled. Lipoma of the stomach has no
malignant potential but if large enough can
bead to an intussusception.
1046 U Scientific Exhibit Volume 16 Number 5
Figures 24, 25. (24) Hpylori infection in a 52-year-
old woman with a history of gastric ulcer disease and
a 3-day history of nausea, vomiting, and inability to
keep food down. Spiral CT scans show gastric wall
thickening especially in the gastric fundus. The differ-
entiab diagnosis included bymphoma and adenocarci-
noma. Endoscopy and biopsy showed gastric ulcers
and Hpj’lori infection but no evidence of malignancy.
(25) Hpylori infection in a 49-year-old woman with a
long history of gastric hypersecretion. Gastric secre-
tion tests revealed elevated gastrin levels. (a) Spiral
CT scan shows a focal mass approximately 1 .8 cm in
diameter in the gastric antrum (arrow). (b) Coronal
reconstruction shows the mass clearly (arrow). The
mass was resected, and pathologic analysis showed
enlarged lymphoid nodules infiltrated by Hpj’lori.
25L
I lori resides within the mucosal layer of the
stomach, especially in the antral region. Up to
60% of adults over 60 years of age are infected
but are usually asymptomatic. H pylon is
found in up to 80% of patients with an active
gastric ulcer and in nearly 100% of patients
with chronic gastritis. The role of Hpylori in
gastric cancer is more controversial. However,
studies show that 80%-90% of patients with
25b.
gastric cancer that arises outside the cardia of
the stomach have antibodies to H pylon.
There is also an increased incidence of B-cell
. CT OF INFlAMMATORY GASTRIC DIS- lymphoma in patients with Hpylori infection.
EASE At CT, Hpyloni infection can simulate an infIl-
trating carcinoma or focal gastric mass (Figs
. Helicobacterpylori Infection 24, 25).
One of the most interesting and complex top-
ics in the discussion of gastric disease is the
Helicobacter pylon bacillus (37-43). Previ-
ously known as Campylobacter pylon, H py-
September 1996 Fishman et al U RadioGrapbics U 1047
- ‘::. ‘“‘
<(% ‘-i,:
Figures 26, 27. (26) Gastritis in a 65-year-old
woman with severe right and left upper quadrant
pain. CT scans show marked thickening and nodu-
barity, which are suspicious for neoplasm (arrow). En-
doscopy and biopsy showed changes compatible with
acute and chronic gastritis. (27) Gastritis in a 62-year-
;,
tv
old woman with severe upper abdominal pain and
gastrointestinal bleeding. CT scan shows markedly ‘‘:
‘p
thickened and edematous gastric folds in a pattern
suggestive of severe inflammation with edema. Cay-
ernous transformation of the portal vein is also seen
(arrow). Endoscopy showed gastritis without cvi-
dence ofHpylori infection.
. ConventlonalGastritis
Gastritis has a number of common and tin-
COmrnOfl causes such as alcohol abuse, aspi-
nfl, and other medications. In most cases, gas-
tritis appears as thickened gastric folds or wall
thickening with wall attenuation similar to that . Gastric Ulcer Disease
of soft tissue (44) (Fig 26). Rarely, it has low CT is often the initial study performed in a pa-
attenuation due to edema (Fig 27). Low attenu- tient with an acute abdomen. In this clinical
ation due to edema or to mucin infiltration of scenario, OflC of the potential causes is gastric
the underlying muscle and soft tissue has also ulcer disease with or without l)crforatiofl. Al-
been reported in mucinous adenocarcinoma of though a perforating ulcer may manifest as
the stomach. Gastritis can he confused with pneumopentoneum, in other Cases the perf#{246}-
tumor infiltration on CT scans, and the diagno- ration is focal and the free air may be localized
sis can then he made only with biopsy. A false- or walled off (Fig 28). In these ascs, CT may
positive diagnosis of gasti-itis can result from demonstrate walled-off air or air bubbles as ab-
poor gastric distention. scesses (45). Jacobs et al (46) described the
findings in 35 patients with peptic ulcer dis-
ease. The findings included CT evidence of
perforating or penetrating ulcer, gastritis with
wall thickening, pneurnoperitoncurn, and free
1048 U Scientific Exhibit Volume 16 Number 5
Figure 28. Gastric ulcer disease in a 7l-year-ld woman with acute abdomen. CT scans show hydropneumo-
peritoneum with the free air best seen anterior to the liver (arrow in a). The gastric fundus is dilated, and there
is perforation of the gastric anti-tim. Note the free air near the perforation site (arrow in b).
(5,000 rad) over a 5-week period (47). The
changes are noted 1 month to 2 years after
therapy. At our institution, radiation gastritis
occurs most often in patients who undergo ra-
diation therapy after a Whipple operation for
pancreatic cancer. The thickening is usually
seen in the area of gastrojejunostomy that cor-
responds to the peak radiation dose center.
The CT and pathologic features of radiation
gastritis are fairly consistent. Gastric wall thick-
ening in a symmetric pattern is often seen.
Small ulcerations may be visible, and the mu-
cosa may appear “shaggy” at CT. Gastric inflam-
mation and ulceration can result in perforation.
One key to recognizing radiation gastritis is not
Figure 29. Radiation gastritis in a 70-year-old
to confuse it with recurrent or residual tumor.
woman after a Whipple operation for pancreatic
Although the appearance may be nearby identi-
cancer and postoperative radiation therapy. CT scan
cal in select cases, radiation gastritis typically
shows thickening and narrowing of the gastric an-
ti-tim (arrows), which correspond to the radiation demonstrates sharp margins that correspond to
ports. the therapy ports (Fig 29). Pathologic injury to
the epithelium of the stomach results in mu-
cosab ulceration and sboughing. Frank ulceration
extravasation of contrast material. Other flOfl- may occur; the probability depends on the cx-
specific findings bike mesenteric or peritoneal tent of associated vascular injury.
inflammation were also seen.
. Radiation Gastritis
Radiation gastritis occurs most commonly in
patients who receive doses above 50 Gy
September 1996 Fishman et al U RadioGrapbics U 1049
Figure 30. Eosinophilic gastroenteritis in a 46-year-old woman with abdominal pain and diarrhea. CT scans
show thickening of the gastric antrum and dilated loops of proximal small bowel. The small bowel folds have a
wet appearance. These findings are most suggestive of eosinophilic gastroenteritis. Minimal fluid in the mesen-
tery is also seen.
a. b.
Figure 31. Biopsy-proved disease
M#{233}n#{233}trier in a 48-year-old man with marked gastric fold thickening through-
out the stomach. CT scans clearly show large, lobulated folds in the gastric fundus.
. Eosinophilic Gastritis . CT OF MISCELLANEOUS GASTRIC
Eosinophilic gastroenteritis is an uncommon DISEASE
disease of unknown origin. The pathologic
findings consist of eosinophilic infiltration of I Disease
M#{233}n#{233}trier
the stomach or bowel in the mucosa, submu- M#{233}n#{233}trier
disease is an uncommon disease of
cosa, or muscularis. The clinical manifestations unknown origin that results in hypertrophy of
range from chronic symptoms such as malab- the gastric folds. The enlargement most corn-
sorption and diarrhea to acute symptoms such monly occurs in the gastric fundus, but any
as gastrointestinal bleeding, abdominal pain, part of the stomach may be involved. At CT,
and obstruction (48,49). CT of the stomach this entity may simulate an infiltrating process
shows a thickened gastric wall (usually 1 -1.5 like lymphoma (50,51) (Fig 31). Rare reports
cm) (Fig 30); antral involvement is most corn- in the literature have described gastroduodenab
mon. Concurrent stomach and small bowel in- intussusception secondary to this condition.
volvement is also common. Case reports have noted adenocarcinoma of
the stomach in patients with bong-standing
disease.
M#{233}n#{233}trier
1050 U Scientific Exhibit Volume 16 Number 5
32a. 32b.
33a.
Figures 32, 33. (32) Emphysematous gastritis in a 63-year-old woman with a history of hemolytic anemia, dia-
betes, and increasing abdominal pain and discomfort. CT scans show air in the gastric wall (arrow). Best seen
posteriorly, the air is compatible with emphysematous gastritis. Endoscopy demonstrated massive infarction of
the entire posterior wall of the stomach. (33) Gastric emphysema in a 47-year-old man with a history of chronic
myebocytic leukemia and a recently placed gastrostomy tube. CT scans show air in the gastric wall without cvi-
dence of perforation or contrast material extravasation. These changes are consistent with gastric emphysema
and were thought to be due to placement of the gastrostomy tube. The patient was treated conservatively and
did well.
. Emphysematous Gastritis and Gas- sematous gastritis. Emphysematous gastritis can
tric Emphysema be caused by ingestion of toxic or caustic sub-
Air in the wall of the stomach can be classified stances, alcohol abuse, trauma, gastric infarc-
as cystic pneumatosis, interstitial gastric em- tion, and gastroduodenitis. The offending organ-
physema, or emphysematous gastritis (52-54). ism is most often Esc/ienichia coli.
Emphysematous gastritis, an infectious gastritis, Gastric emphysema is a benign condition
is a life-threatening condition (mortality rate, in which the stomach wall is not thickened;
60%-80%) caused by bacterial invasion of the however, thin, linear streaks of air are seen in
gastric wall with gas production. The CT ap- the wall. The patient is usually asymptomatic,
pearance consists of mottled air in the gastric and the air tends to resolve spontaneously
wall with associated thickened gastric folds. It over time without bong-term sequebae. Cystic
may be difficult to distinguish between emphy- pneumatosis is also a benign condition. It is
sematous gastritis and more benign conditions typically an incidental fmding at endoscopy,
solely on the basis of the CT appearance (Figs CT, or barium study.
32, 33). Such differentiation is obviously impor-
tant in bight of the high mortality rate of emphy-
September 1996 Fishman et al U RadioGraphics U 1051
Figure 34 Gastric varices in a 41-year-old man with a history of hepatitis C, cirrhosis, and bright red blood
from the rectum. Spiral CT scans acquired with water used for gastric distention show large varices in the gas-
tric fundus. In patients evaluated for vascular disease, air or water is the agent of choice for stomach and bowel
opacification.
. Gastric Varices need to optimize CT protocols suggests that CT
Gastric varices are more commonly seen and can provide important, accurate, and detailed
easier to define with the increased use of spiral information on neoplastic and inflammatory dis-
CT coupled with rapid injection of iodinated ease. Although classic upper gastrointestinal
contrast material (55) (Fig 34). Balthazar et al studies and endoscopy play a major role in
(55) describe gastric varices as enhancing, tubu- evaluation of the stomach, CT has unique at-
bar structures most commonly seen in the fun- tributes that make it an ideal examination. In
dus of the stomach. Collateral vessels are corn- the future, the roles of endoscopic ultrasound
monly seen in the region of the gastrohepatic (57) and magnetic resonance imaging in evalu-
ligament, near the lesser omentum, and along ating the stomach will need to be ftirther cx-
the course of the coronary vein. Associated plored; however, CT is a cost-effective study
esophageal varices may also be seen. On non- and will remain an important imaging tool.
enhanced CT scans or CT scans obtained with
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1054 U Scientific Exhibit Volume 16 Number 5
