|Effect of subclinical Helicobacter pylori infection on gastric wall thickness: multislice CT evaluation
|Sibel Kul1, Burak Sert1, Ahmet Sarı1, Mehmet Arslan2, Polat Koşucu1, Ali Ahmetoğlu1, Hasan Dinç1
|1 From the Departments of Radiology, Karadeniz Technical University School of Medicine, Trabzon, Turkey
2 Departments of Gastroenterology, Karadeniz Technical University School of Medicine, Trabzon, Turkey
|Keywords: Helicobacter pylori • gastritis • gastric wall • multidedector CT
To evaluate the effect of subclinical Helicobacter pylori
infection on the gastric wall thickness with multislice
computed tomography (MSCT).
MATERIALS AND METHODS
In 99 subjects without gastric disease, CT scans of the
abdomen were obtained after water ingestion and
intravenous contrast administration. CT images were
evaluated for degree of luminal distention and the
thickness of the walls of the gastric antrum and body.
We also looked for other radiological signs of gastritis
such as the presence of fold thickening, mucosal
enhancement, submucosal hypodensity, focal gastric
mass-like lesion, and focal wall thickening. All subjects
were tested with rapid urease test or stool antigen
test and grouped as H. pylori positive or negative
according to the results.
The average gastric body and antrum wall thicknesses
did not show statistically significant difference
between H. pylori positive and negative groups.
The average antral wall thickness was greater than
the gastric body wall thickness in 68.5% of cases,
independent of H. pylori positivity; and antral wall
thickness was more than 5 mm in more than 50% of
cases. There were no significant differences between
the groups in terms of other signs of gastritis.
Wall thickening of gastric antrum relative to gastric
body is a common finding even in the use of MSCT,
and antral thickness commonly exceeds 5 mm. Subclinical
H. pylori infection has no effect on gastric wall
Gastric wall thickening is one of the most important signs of gastrointestinal
diseases. Results of many studies suggest that normal
gastric wall thickness ≤5 mm on computed tomography
(CT). However, the wall of the gastric antrum is often thickened on CT,
and 5 mm may not be an appropriate cutoff.
The antrum is the most common site of involvement for Helicobacter
pylori, one of the most prevalent human pathogens worldwide. More
than 90% of the population in developing countries and 50% of the
population in developed countries are infected with H. pylori. The bacterium
colonizes and infects the stomach. It is now well known that
infection commonly shows a subclinical course and causes histological
gastritis . We investigated the effect of subclinical H. pylori infection
on gastric wall thickness.
This study included patients referred to the department of radiology at
our institution for abdominal CT examination during a 5-month period.
Exclusion criteria were symptoms of dyspepsia or pain, history of prior
gastric surgery, known or suspected diagnosis of abdominal malignancy,
known or suspected diagnosis of acute pancreatitis or inflammatory
bowel disease, previous history of abdominal surgery and/or abdominal
radiotherapy, use of nonsteroidal antiinflammatory drugs, previous
treatment for H. pylori infection, and contraindications for use of intravenous
iodinated contrast agent.
Ninety-nine patients (52 males and 47 females; age range, 18–82
years; mean age, 51 years) constituted the study population. After
the multislice computed tomography (MSCT) scan, rapid urease test
of the endoscopic biopsy material or stool antigen test was used to
detect H. pylori. Forty-three patients who consented to endoscopy underwent
upper gastrointestinal endoscopy and biopsy at the gastroenterology
department. Endoscopic features of increased vascularity,
edema, rugal hypertrophy or atrophy, erythema, and erosions were
considered signs of gastritis. Rapid urease test (CLO test, Delta West
Ltd., Perth, Australia) was applied to the biopsy materials; the change
of the color indicator from red to yellow was considered positive
for H. pylori. Stool antigen test (Rapid HpSA Test, Linear Chemicals,
Spain) was performed at the microbiology department for the 56 patients
who did not consent to the endoscopic procedure. The appearance
of pink-blue color in addition to blue control line on reaction
stripe was considered a positive result. The institutional review board
approved the study, and informed consent was obtained from all participating
MSCT scanning of the abdomen was
performed with a Somatom Volume
Zoom scanner (Siemens, Germany).
Standard scanning parameters were
120 kVp, 165 mAs, 4 × 2.5 mm collimation,
and 0.5-s tube rotation. Images
were reconstructed with 5-mm
sections for routine review on film and
workstation. Patients fasted ≥6 hours
before scanning. Patients were given
750 mL of water approximately 15 minutes
before scanning and an additional
250 mL immediately before the scanning.
Images were obtained at portal
venous phase with 60-s delay after the
administration of 120 mL of non-ionic
intravenous contrast material iohexol
(Amersham Health, Ireland) or iopromide
(Schering, Berlin, Germany) via
the antecubital vein with automatic injector
(Medrad Vistron CT, Pittsburgh,
Pennsylvania, USA) at a rate of 3 mL/s.
Dual-phase imaging was performed in
some patients according to scanning
indications, but the arterial phase images
were not evaluated in this study.
Scanning was done from dome of the
diaphragm to the iliac crest for the upper
abdomen and to the symphysis
pubis for the whole abdomen at prone
Evaluation of CT images
The obtained CT images were transferred
to the work station (Virtuosa,
Siemens, Germany). Two reviewers
together evaluated the images for gastric
distention, wall morphology, and
thickness on computer without prior
knowledge of the results of H. pylori
tests. Luminal distension was scored
according to the diameter of the gastric
lumen. A gastric body luminal
diameter <5 cm was interpreted as
grade 0; 5–8 cm as grade 1; and >8 cm
as grade 2. A gastric antrum luminal
diameter <2.5 cm was interpreted as
grade 0; 2.5–4 cm as grade 1; and >4
cm as grade 2. Grade 0 luminal distension
was interpreted as insufficient,
and grade 2 luminal distension was
The wall thicknesses at the sides of
greater and lesser curvatures of the
gastric body and antrum were measured
on axial images using electronic
calipers. For the gastric body, the lesser
and the greater curvature wall thicknesses
were measured on the medial
and the lateral walls, respectively (Fig.
). For the antrum, the lesser and the
greater curvature wall thicknesses were
measured on the anterior and the posterior
walls, respectively (Fig.
the gastric body, the midline slice between
the esophagogastric junction
and incisura angularis was selected; for
the antrum, the midline slice between
the incisura angularis and antropyloric
junction was selected. The measurements
were taken perpendicular to the
gastric wall, and the folds were not included.
The CT scans were also evaluated
for the presence of known CT criteria
of gastritis. Gastric wall >5 mm was
assumed to be thickened. The thickened
wall was evaluated for symmetry
as circumferential or asymmetric, and
for focal vs. diffuse distribution. Gastric
folds >5 mm were considered to be
thickened; greater enhancement of the
mucosa than the gastric wall was considered
significant. Thickened folds,
mucosal enhancement, presence of
low attenuating stripe of the submucosal
layer, and enhancing focal gastric
masses were also noted for all CT
Click to Enlarge
|Figure 1: a, b. CT images show the sites of measurements for lesser \(1\) and greater curvature \(2\) wall thicknesses of the gastric body (a) and the gastric antrum (b).
For the purpose of this study, patients
were grouped as H. pylori positive
and negative according to the
results of H. pylori tests. The wall
thicknesses at the greater and lesser
curvature of the gastric body and the
antrum were expressed as the mean
and standard deviation with 95% confidence
intervals. The statistical analysis
was performed with SPSS statistical
package (SPSS Inc. Chicago, Illinois,
USA). The differences in wall thicknesses
between H. pylori positive and
negative groups were evaluated by using
Student t test at the antrum and
by using Mann-Whitney U test at the
gastric body. P < 0.05 was considered
statistically significant. The relationships
of the luminal distention and
age to gastric wall thickness were evaluated
by Pearson correlation test.
The presence of the other CT findings
of gastritis such as the circumferential
antral wall thickening, fold thickening,
mucosal enhancement, submucosal
hypodense stripe, focal gastric mass,
and focal thickening of the posterior
gastric wall along the greater curvature
were evaluated for both groups; and
the results were analyzed statistically
by chi-square test. P < 0.05 was considered
The gastric body and the antrum
were easily identified in all patients.
According to the results of rapid urease
and stool antigen tests, of 99 patients,
43 (43.4%) were H. pylori positive and
56 (56.6%) were negative. H. pylori positivity
was detected in 20 of 43 (46%)
patients tested with the rapid urease
test and 23 of 56 (41%) patients tested
with the stool antigen test.
The luminal distension of the gastric
body was grade 1 in 13 (13.1%) and
grade 2 in 86 (86.9%) patients; luminal
distension of the gastric antrum
was grade 0 in 2 (2%), grade 1 in 38
(38.4%), and grade 2 in 59 (59.6%).
Insufficient distension was observed at
the gastric antrum in two cases, one H.
pylori positive and the other H. pylori
negative, with mean antral wall thicknesses
of 6.3 mm and 5.3 mm, respectively.
The distribution of the distension
scores did not show significant
difference between H. pylori positive
and negative groups. The correlation
between the gastric distention and
the wall thickness was evaluated for
gastric body and antrum revealed no
correlation (P = 0.491 and P = 0.578,
respectively). Also, no correlation was
detected between age and wall thickness
(P > 0.05).
The mean antral wall thicknesses
(mean ± SD) at the greater curvature of
H. pylori positive and negative groups
were 4.80 ± 1.81 mm and 5.45 ± 2.09
mm; at the lesser curvature, mean antral
wall thicknesses were 4.72 ± 1.74
mm and 4.96 ± 1.90 mm, respectively.
For antral wall thickness, there was no
significant difference between H. pylori
positive and negative groups at the
greater (P = 0.099) or lesser curvature (P
= 0.523). The average antral wall thicknesses
were 4.77 ± 1.72 mm and 5.21
± 1.88 mm for H. pylori positive and
negative groups, respectively.
The mean gastric body wall thicknesses
at the greater curvature were
3.80 ± 1.28 mm and 3.43 ± 0.70 mm
and at the lesser curvature were 4.38 ±
1.63 mm and 3.83 ± 0.85 mm for H.
pylori positive and negative groups,
respectively. The wall thickness of the
greater curvature of gastric body did
not demonstrate significant difference
between H. pylori positive and negative
groups (P = 0.095), whereas for the lesser
curvature, borderline significance
(P = 0.047) was detected. Averages of
the wall thicknesses of two curvatures
were 4.09 ± 1.40 mm and 3.63 ± 0.74
mm for H. pylori positive and negative
groups, respectively. However, the difference
between the groups was not
statistically significant. Table summarizes
the mean wall thicknesses for H.
pylori positive and negative groups.
Click to Enlarge
|Table 1: Mean and minimum–maximum wall thicknesses at greater and lesser curvatures of the stomach for H. pylori positive and negative groups
Circumferential antral wall thickening
was found in 13 (30.2%) of 43 H.
pylori positive cases and in 21 (37.5%)
of 56 H. pylori negative cases (Fig. 2).
The difference between the two groups
was not statistically significant (P =
0.588). Thickened folds were found in
six (14%) of 43 H. pylori positive cases
and in 10 (17.9%) of 56 H. pylori negative
cases; the difference between two
groups was not significant (P = 0.579).
Mucosal enhancement was found in
nine (20.9%) of 43 H. pylori positive
cases and in 17 (30.4%) of 56 H. pylori
negative cases (Fig. 3). The difference
between two groups was not significant
(P = 0.409).
Click to Enlarge
|Figure 2: Contrast enhanced abdominal CT image of a 41-year-old woman with breast cancer demonstrates marked circumferential wall thickening of grade 1 distended antrum without gastric body wall thickening. Her stool antigen test was negative.
Click to Enlarge
|Figure 3: Contrast-enhanced abdominal CT image of a 72-year-old woman with negative stool antigen test demonstrates marked mucosal enhancement of the stomach.
Submucosal hypodense stripes were
found in four (9.3%) of 43 H. pylori
positive cases and 13 (23.2%) of 56 H.
pylori negative cases. The difference between
two groups was not significant
(P = 0.121). The focal gastric mass-like
lesion was found in five (11.6%) of 43
H. pylori positive cases and two (3.6%)
of 56 H. pylori negative cases (Fig. 4).
The number of cases was not sufficient
for statistical comparison. Focal thickening
of the posterior gastric wall along
the great curvature was found in eight
(18.6%) of 43 H. pylori positive cases
and in nine (16.1%) of 56 H. pylori negative
cases; the difference between two
groups was not significant (P = 0.950).
Click to Enlarge
|Figure 4: Contrast-enhanced abdominal CT image of a 33-year-old woman with hydatid cyst of the liver, shows a non-contrast enhancing focal mass-like lesion of 15–19 mm, located on the posterior wall of the grade 1 distended antrum and relative thickening of the antrum compared with gastric body. Endoscopic examination did not demonstrate any mass lesion, and H. pylori test was negative.
Gastric wall thickening is one of
the most important signs of gastrointestinal
disease. CT, particularly using
multislice technology, is a very effective
imaging modality in evaluation
of the gastric wall, assessing its thickness
and contour. For gastric evaluation,
adequate distension of stomach
is essential. Water is a commonly used
oral contrast agent for gastric distention;
it is well tolerated, inexpensive,
and results in good gastric distension
as well as excellent visualization of the
enhancing gastric wall. It also allows
accurate measurement of gastric wall
thickness. Intravenous contrast material
is also necessary for the complete
evaluation of neoplastic and inflammatory
diseases of the stomach [2
Most sources report that a normal
gastric wall thickness is 5 mm or less
in an adequately distended stomach
at CT [3-6]. However, the antral wall
is usually thicker than the other parts
of the stomach wall. Using MSCT,
Pickhardt and Asher  evaluated the
gastric antrum wall thickness in 153
patients without gastric disease. They
concluded that the smooth wall thickening
of the gastric antrum relative to
the proximal stomach was a normal
finding; they found that antral wall
thickness commonly exceeded 5 mm,
and thickness up to 12 mm was seen in
the absence of disease. H. pylori is the
most common cause of antral thickening,
and it commonly has a subclinical
course. However, it is not known if
there is a relationship between subclinical
H. pylori infection and antral wall
H. pylori is a motile, gram-negative
bacterium which has the ability to
colonize and infect the stomach. It can
infect the gastric antrum and/or body,
but inflammation tends to be more severe
at gastric antrum. It causes chronic
gastritis, peptic ulcer, and lymphoproliferative
diseases, and it is a major risk
factor for gastric cancer. It is the most
frequent cause of gastritis in the adult
population throughout the world,
present in nearly 50% of symptomatic
patients undergoing endoscopic examination
(1, 8–11). Infection can also be
seen in asymptomatic persons. Doolley
et al.  reported a 32% prevalence
of H. pylori infection in asymptomatic
persons. In our study population, the
prevalence of asymptomatic infection
was 43.3%, which was higher than
that reported in the literature; this was
thought to be the result of regional differences.
H. pylori infection can be diagnosed
by invasive and noninvasive techniques
such as the histological examination,
the urea breath test, several
serum tests, and the stool antigen test.
According to European H. pylori Study
Group, diagnosis of infection should
be by urea breath test or stool antigen
The most common CT findings of
H. pylori gastritis are thickening of the
gastric folds and wall . Urban et al.
reviewed CT scans of 61 biopsy-proven
cases of H. pylori gastritis retrospectively
and found gastric abnormality in
31% of patients . Of the gastric abnormalities,
68% were circumferential
antral wall thickening and 42% were
posterior gastric wall thickening along
the greater curvature. In severe cases,
the gastric wall may also demonstrate
low attenuation or the mucosa may
enhance. Infection sometimes can simulate
an infiltrating carcinoma or focal
gastric mass [14-17].
In our study group of patients without
gastric complaints or known gastric
disease, the gastric body and the antrum
average wall thicknesses did not
show statistically significant difference
between H. pylori positive and negative
groups. At the lesser curvature, the gastric
body wall was found to be slightly
thicker (4.39 mm) for H. pylori positive
cases than the control group, but this
was not more than 5 mm, which is the
commonly accepted cutoff point for
abnormal thickening. In the literature,
there is no reported association between
the lesser curvature wall thickening
and H. pylori infection. Thus this
difference might be incidental.
Although, Pickhardt and Asher reported
smooth wall thickening of the
distal gastric antrum relative to the
gastric body in 99% of 153 cases ,
we found the average antral wall thickness
was greater than the gastric body
wall thickness in 29 (67.4%) of 43 H.
pylori positive cases and in 39 (69.6%)
of 56 H. pylori negative cases. In 41.8%
of the H. pylori positive cases and in
57.0% of the H. pylori negative cases,
at least one antral wall thickness was
>5 mm (range, 5.1–9.3 mm). Our findings
show that the greater thickness of
the gastric antrum wall than the gastric
body wall is a common finding, even
using MSCT; it is independent of H.
pylori positivity. Because antral thickness
commonly exceeded 5 mm, we
concluded that a 5-mm point may not
be appropriate in evaluating the gastric
Thickened gastric folds, low attenuation
of the gastric wall, mucosal enhancement,
and focal or circumferential
wall thickening are the well-known
CT features of the gastritis [14-17]. We
demonstrated these findings in both H.
pylori positive and negative cases, and
there was no significant difference between
Gastritis was demonstrated in 20 of
the 43 cases undergoing endoscopic
examination; all were H. pylori positive.
Gastritis was found at the gastric body
in two (10%), at the gastric antrum in
seven (35%), and at both antrum and
body in 11 (55%) cases. We could not
provide endoscopic correlation in all
patients because of its invasive nature.
Endoscopic correlation is important to
exclude causes of antral inflammation
and gastric wall thickening other than
H. pylori. However, the results obtained
from whole study population were
consistent with the results of 43 endoscopically
In conclusion, the wall thickening
of the gastric antrum relative to
the gastric body is a common finding
when using MSCT; antral thickness
commonly exceeds 5 mm. However,
subclinical H. pylori infection does
not affect wall thicknesses of either
the gastric antrum or the gastric body.
The gastric body wall thickening at the
lesser curvature found in H. pylori positive
cases is of borderline significance
and thought to be incidental. Gastric
mucosal enhancement is a common
finding, but like other less commonly
observed CT findings of gastritis, may
be seen in both subclinical H. pylori infection
and normal stomach and is not
a differentiating feature.
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