Published online before print May 20, 2003, 10.1148/radiol.2281020623
(Radiology 2003;228:166-171.)
© RSNA, 2003
Benign and Malignant Lesions of the Stomach: Evaluation of CT Criteria for Differentiation1
Erik K. Insko, MD, PhD,
Marc S. Levine, MD,
Bernard A. Birnbaum, MD2 and
Jill E. Jacobs, MD2
1 From the Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104. Received May 28, 2002; revision requested July 26; revision received September 19; accepted November 18. Address correspondence to E.K.I. (e-mail: insko@rad.upenn.edu).
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ABSTRACT
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PURPOSE: To determine the sensitivity and specificity of computed tomographic (CT) criteria for differentiating benign from malignant stomach lesions in patients with a thickened gastric wall at CT.
MATERIALS AND METHODS: A radiology department file search revealed 36 patients with a thickened gastric wall at CT who underwent double-contrast barium suspension upper gastrointestinal tract examinations within 6 weeks before or after CT. The authors reviewed the CT images without knowledge of the final radiologic, endoscopic, or pathologic findings to determine the degree of gastric wall thickening and the symmetry, distribution, and enhancement of the thickened wall. The sensitivity and specificity of these findings for detection of malignancy were calculated.
RESULTS: Two of 36 patients had two gastric abnormalities each. The final diagnoses in the 38 cases were gastritis in 19, hiatal hernia in four, benign ulcer in three, benign (n = 3) or malignant (n = 8) gastric neoplasm in 11, and no gastric abnormality in one case. Mean wall thickness was 1.5 cm (range, 0.7–7.5 cm). The finding of gastric wall thickness of 1 cm or greater had a sensitivity of 100% but a specificity of only 42% for detection of malignant or potentially malignant stomach lesions. The finding of focal, eccentric, or enhancing wall thickening had a sensitivity of 93%, 71%, or 43%, respectively, and a specificity of 8%, 75%, or 88%, respectively, for detection of these lesions. Gastric wall thickening that was 1 cm or greater and was focal, eccentric, and enhancing had a specificity of 92% but a sensitivity of only 36% for detection of these lesions.
CONCLUSION: Gastric wall thickness of 1 cm or greater at CT had a sensitivity of 100% but a specificity of less than 50% for detection of malignant or potentially malignant stomach lesions that necessitated further diagnostic evaluation.
© RSNA, 2003
Index terms: Gastritis, 72.291 • Gastrointestinal tract, CT, 72.12112, 72.12115 • Gastrointestinal tract, radiography, 72.123 • Stomach, CT, 72.12112, 72.12115 • Stomach, neoplasms, 72.31, 72.32
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INTRODUCTION
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When evaluating the stomach with computed tomography (CT), it is important to be able to differentiate benign conditions such as gastritis from ulcers or neoplasms that necessitate further assessment with barium or endoscopic examinations. However, evaluation of the stomach at CT may be limited by a variety of factors, including gastric peristalsis, incomplete distention, an inadequate volume of oral contrast material, and retained food. The results of several previously performed studies (1–4) have shown that a normal gastric wall usually has a thickness of 5 mm or less at CT, whereas a gastric wall involved by tumor usually has a thickness of 1 cm or greater. However, in the radiologic literature, apart from the data on degree of wall thickness, there is little information regarding the CT criteria for differentiating normal stomach or benign conditions such as gastritis from potentially malignant lesions that necessitate further diagnostic evaluation.
Our experience has been that patients who are suspected of having gastric neoplasms because of a thickened wall at CT not infrequently are found to have gastritis or even a normal stomach at barium or endoscopic examinations. Considering the established CT criteria for differentiating benign from malignant lesions of the small or large bowel (5), we wondered whether the degree of gastric wall thickening combined with other criteria such as symmetry, distribution, and enhancement of the thickened gastric wall might enable radiologists to better differentiate benign from malignant conditions involving the stomach at CT. With this background, we performed a blinded retrospective study involving a large series of patients who underwent abdominal CT, as well as barium suspension examination, endoscopy, and/or surgery, to determine the sensitivity and specificity of CT criteria in the differentiation of benign and malignant disease involving the stomach in patients with a thickened gastric wall at CT.
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MATERIALS AND METHODS
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Patient Selection
A computerized search of our hospital’s radiology files by one author (E.K.I.) during a 3-year period from 1997 to 1999 revealed 152 patients with a thickened gastric wall at abdominal CT (keyword searches: thickened, bulky, prominent, abnormal) who had also undergone double-contrast barium suspension examinations of the upper gastrointestinal (UGI) tract. One hundred sixteen patients were excluded from analysis for any of the following reasons: (a) The CT study was performed without intravenously administered contrast material, (b) the CT images could not be retrieved from our image archives, (c) a blinded review of the CT images revealed no definite abnormalities of the gastric wall and no inadequate distention of the stomach, (d) the interval between CT and barium suspension examination was longer than 6 weeks, and (e) the patients had undergone gastric surgery previously.
The remaining 36 patients comprised our study group. These 36 patients had a total of 38 suspected gastric abnormalities at CT. The mean interval between CT and double-contrast UGI barium suspension examination was ±12.1 days (range, 1–32 days). The mean age of the patients was 52 years (age range, 35–80 years). Seventeen patients were men and 19 women. Our institutional review board approved all aspects of this retrospective study and did not require informed consent from the patients whose records were included in our study.
CT Technique
All patients included in the study underwent helical CT of the abdomen (with a CT HiSpeed Advantage or HiSpeed CT/I unit; GE Medical Systems, Milwaukee, Wis) according to an established protocol. All patients received oral contrast material (600–800 mL of 2%–3% diatrizoate meglumine and diatrizoate sodium [Gastrografin]; Bristol-Myers Squibb, Princeton, NJ, or a 2.1% wt/vol barium suspension [Readi-cat], E-Z-Em, Westbury, NY) 30–45 minutes before the CT examination and an additional 400–500-mL dose of the oral contrast material followed by 3 g of an oral effervescent agent dissolved in 8 ounces of water (Baros; Lafayette Pharmaceuticals, Lafayette, Ind) immediately before the examination. All patients also received a 150-mL injection of 60% iodinated contrast material (diatrizoate meglumine [Hypaque] or iohexol [Omnipaque 300]; Nycomed Amersham, Princeton, NJ) through an antecubital vein at a rate of 2–3 mL/sec. The CT images were routinely obtained with the patient in a supine position during full inspiration. In one case, prone-position CT images of the stomach also were acquired. CT images of the upper abdomen were obtained by using either 5-mm collimation and a pitch of 1.5:1.0 or 7-mm collimation and a pitch of 1.3:1.0 (200–220 mAs); transverse images were reconstructed with a soft-tissue algorithm.
UGI Examination Technique
All patients underwent double-contrast examinations of the UGI tract that were performed by using digital fluoroscopic equipment (Diagnost 76 Plus; Philips, Eindhoven, the Netherlands). These studies, which were performed as biphasic examinations by using an effervescent agent (Baros) and a 250% wt/vol barium suspension (E-Z-HD; E-Z-Em) followed by a 50% wt/vol barium suspension (Entrobar; Lafayette Pharmaceuticals), have been described previously (6). All UGI examinations were performed by a supervised resident (E.K.I.) or an attending UGI radiologist (M.S.L.).
Image Review
The images acquired at CT scanning in the 36 patients were reviewed by consensus between two CT radiologists (B.A.B., 13 years experience; J.E.J., 10 years experience) who had no knowledge of the final radiologic, endoscopic, or pathologic findings. The greatest visible gastric wall thickness was measured with electronic calipers at a picture archiving and communications, or PACS, workstation. All 38 cases involved a gastric wall thickness of greater than 5 mm, which is a previously established CT criterion for an abnormally thickened gastric wall (1,2). The thickened wall was also evaluated for symmetry (ie, eccentric or asymmetric vs circumferential or symmetric), distribution (ie, focal vs diffuse), and presence or absence of enhancement after intravenous contrast material administration.
Final Diagnosis
The reports from the double-contrast UGI examinations, as well as those from the endoscopic, surgical, and/or pathologic examinations, were reviewed by one author (E.K.I.). If the patient underwent double-contrast UGI examination but not endoscopy, the UGI findings were accepted as the final diagnosis or the reference standard. If the patient underwent endoscopy or surgery, as well as double-contrast UGI examination, the endoscopic or histopathologic findings in the endoscopic biopsy specimens or resected surgical specimens were accepted as the reference standard. Although it is conceivable that one or more malignant tumors could have been missed on the barium images, we believe that the findings on these images were a reasonable reference standard in the absence of endoscopic or pathologic correlation, because double-contrast UGI studies have been shown to have a sensitivity of greater than 95% in the detection of gastric carcinomas (7). The final diagnosis was based on the UGI findings in 16 patients, on the histopathologic findings at endoscopy alone in 13 patients, on the endoscopic and surgical findings in six patients, and on the surgical findings alone in one patient. Two patients each were found to have two separate abnormalities in the stomach. The diagnoses of these lesions were based on the histopathologic findings at endoscopy alone in one patient and on the findings at endoscopy and surgery in the other patient. There were no discrepancies between the UGI examination findings and the endoscopic or histopathologic findings in the 19 patients who underwent endoscopy or surgery and barium (ie, UGI) examinations.
Criteria for Evaluating Accuracy of CT
For the purposes of this study, all patients with a final diagnosis of a gastric ulcer or neoplasm were considered to have potentially malignant lesions that warranted further diagnostic evaluation with a double-contrast UGI or endoscopic examination. Ulcers were included in this group, because we are aware of no reliable criteria for differentiating benign ulcers from malignant ulcers on the basis of CT findings. Gastrointestinal stromal tumors also were included in this group, because 10%–30% of these neoplasms are found to be malignant (8). Conversely, patients with a final diagnosis of gastritis, hiatal hernia, or a normal stomach were considered to have findings that did not warrant further diagnostic evaluation. We then calculated the sensitivity and specificity of the various parameters of gastric wall thickening in the detection of malignant or potentially malignant stomach lesions in our study group.
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RESULTS
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In the 38 cases of a thickened gastric wall at CT, the mean wall thickness was 1.5 cm (range, 0.7–7.5 cm). The wall thickness was 1 cm or greater in 28 (74%) cases and less than 1 cm in the remaining 10 (26%). The final diagnoses were gastritis in 19 (Figs 1, 2), hiatal hernia in four (Fig 3), benign ulcer in three (Fig 4), and gastric neoplasm in 11 cases: seven gastric carcinomas (four infiltrating carcinomas, one ulcerated carcinoma, and two scirrhous carcinomas [Figs 5, 6]), three benign gastrointestinal stromal tumors (Fig 7), and one esophageal carcinoma invading the gastric fundus. No abnormalities were found in the stomach in the remaining case. Thus, in the 38 cases of a thickened gastric wall at CT, the stomach was either involved by benign disease (n = 23) or normal (n = 1) in 24 cases, which warranted no further diagnostic evaluation, whereas malignant or potentially malignant lesions were present in 14 cases, which warranted further evaluation with barium or endoscopic examinations.
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Figure 1a. Antral gastritis in a 73-year-old woman. (a) Transverse contrast material-enhanced CT image shows focal symmetric thickening (arrow) of the wall of the gastric antrum and no evidence of enhancement. The antral wall has a thickness of 1.2 cm in this region. (b) Left posterior oblique double-contrast UGI image shows slightly thickened folds (arrow) in the gastric antrum that are compatible with mild antral gastritis. Endoscopic biopsy specimens (not shown) revealed chronic inflammatory changes in the antrum and no evidence of tumor.
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Figure 1b. Antral gastritis in a 73-year-old woman. (a) Transverse contrast material-enhanced CT image shows focal symmetric thickening (arrow) of the wall of the gastric antrum and no evidence of enhancement. The antral wall has a thickness of 1.2 cm in this region. (b) Left posterior oblique double-contrast UGI image shows slightly thickened folds (arrow) in the gastric antrum that are compatible with mild antral gastritis. Endoscopic biopsy specimens (not shown) revealed chronic inflammatory changes in the antrum and no evidence of tumor.
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Figure 2. Transverse contrast-enhanced CT image obtained in a 59-year-old woman with antral gastritis shows focal asymmetric thickening (arrow) of the anterior wall of the gastric antrum and no evidence of enhancement. The antral wall has a thickness of 1.0 cm in this region. Subsequently obtained double-contrast UGI tract image (not shown) revealed antral gastritis with thickened antral folds but no evidence of tumor.
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Figure 3a. Hiatal hernia in a 77-year-old woman. (a) Transverse contrast-enhanced CT image shows focal asymmetric thickening (arrow) of the posteromedial wall of the gastric fundus in the region of the cardia and no evidence of enhancement. The fundal wall has a thickness of 2.0 cm in this region. (b) Right lateral double-contrast UGI tract image shows a hiatal hernia (arrow) and no evidence of tumor in the gastric fundus. In retrospect, the focal wall thickening of the stomach that was depicted at CT probably resulted from incomplete distention of the hiatal hernia, with prolapse of the hernia into the fundus.
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Figure 3b. Hiatal hernia in a 77-year-old woman. (a) Transverse contrast-enhanced CT image shows focal asymmetric thickening (arrow) of the posteromedial wall of the gastric fundus in the region of the cardia and no evidence of enhancement. The fundal wall has a thickness of 2.0 cm in this region. (b) Right lateral double-contrast UGI tract image shows a hiatal hernia (arrow) and no evidence of tumor in the gastric fundus. In retrospect, the focal wall thickening of the stomach that was depicted at CT probably resulted from incomplete distention of the hiatal hernia, with prolapse of the hernia into the fundus.
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Figure 4a. Benign gastric ulcer in a 72-year-old man. (a) Transverse contrast-enhanced CT image shows focal asymmetric thickening (arrow) of the wall of the gastric antrum and no evidence of enhancement. The antral wall has a thickness of 1.3 cm in this region. In retrospect, barium was probably trapped in an antral ulcer (arrowhead). (b) Frontal double-contrast UGI tract image shows an ulcer (black arrow) in the distal antrum with a large surrounding mound of edema (white arrows). Endoscopic biopsy specimens (not shown) confirmed the presence of a benign gastric ulcer with Helicobacter pylori gastritis.
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Figure 4b. Benign gastric ulcer in a 72-year-old man. (a) Transverse contrast-enhanced CT image shows focal asymmetric thickening (arrow) of the wall of the gastric antrum and no evidence of enhancement. The antral wall has a thickness of 1.3 cm in this region. In retrospect, barium was probably trapped in an antral ulcer (arrowhead). (b) Frontal double-contrast UGI tract image shows an ulcer (black arrow) in the distal antrum with a large surrounding mound of edema (white arrows). Endoscopic biopsy specimens (not shown) confirmed the presence of a benign gastric ulcer with Helicobacter pylori gastritis.
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Figure 5a. Ulcerated carcinoma of the stomach in an 82-year-old man. (a) Transverse contrast-enhanced CT image shows focal asymmetric thickening (arrow) of the medial wall of the proximal gastric body and heterogeneous enhancement. The antral wall has a thickness of 1.6 cm in this region. (b) Left posterior oblique double-contrast UGI tract image shows a polypoid mass (black arrows) with a flat central ulcer (white arrow) in the lesser curvature of the proximal gastric body. Endoscopic results (not shown) confirmed the presence of an ulcerated mass in the stomach, and biopsy specimens (not shown) revealed gastric adenocarcinoma. The lesion was surgically resected.
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Figure 5b. Ulcerated carcinoma of the stomach in an 82-year-old man. (a) Transverse contrast-enhanced CT image shows focal asymmetric thickening (arrow) of the medial wall of the proximal gastric body and heterogeneous enhancement. The antral wall has a thickness of 1.6 cm in this region. (b) Left posterior oblique double-contrast UGI tract image shows a polypoid mass (black arrows) with a flat central ulcer (white arrow) in the lesser curvature of the proximal gastric body. Endoscopic results (not shown) confirmed the presence of an ulcerated mass in the stomach, and biopsy specimens (not shown) revealed gastric adenocarcinoma. The lesion was surgically resected.
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Figure 6a. Scirrhous carcinoma of the stomach in a 61-year-old man. (a) Transverse contrast-enhanced CT image shows focal circumferential thickening (arrow) of the wall of the gastric antrum and heterogeneous enhancement. The antral wall has a thickness of 2.0 cm in this region. (b) Left posterior oblique double-contrast UGI tract image shows irregular narrowing of the gastric antrum (arrows). Endoscopic biopsy specimens (not shown) revealed scirrhous adenocarcinoma of the stomach.
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Figure 6b. Scirrhous carcinoma of the stomach in a 61-year-old man. (a) Transverse contrast-enhanced CT image shows focal circumferential thickening (arrow) of the wall of the gastric antrum and heterogeneous enhancement. The antral wall has a thickness of 2.0 cm in this region. (b) Left posterior oblique double-contrast UGI tract image shows irregular narrowing of the gastric antrum (arrows). Endoscopic biopsy specimens (not shown) revealed scirrhous adenocarcinoma of the stomach.
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Figure 7a. Gastrointestinal stromal tumor in a 52-year-old man. (a) Transverse contrast-enhanced CT image shows focal masslike thickening (arrow) of the posterior wall of the fundus. This wall has lower attenuation than the adjacent wall and no evidence of enhancement. The lesion has a thickness of 2.2 cm. (b) Right lateral double-contrast UGI tract image shows a smooth submucosal-appearing mass (arrow) on the posterior wall of the gastric fundus. Endoscopic biopsy specimens (not shown) revealed a gastrointestinal stromal tumor in the gastric fundus. The lesion was surgically resected.
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Figure 7b. Gastrointestinal stromal tumor in a 52-year-old man. (a) Transverse contrast-enhanced CT image shows focal masslike thickening (arrow) of the posterior wall of the fundus. This wall has lower attenuation than the adjacent wall and no evidence of enhancement. The lesion has a thickness of 2.2 cm. (b) Right lateral double-contrast UGI tract image shows a smooth submucosal-appearing mass (arrow) on the posterior wall of the gastric fundus. Endoscopic biopsy specimens (not shown) revealed a gastrointestinal stromal tumor in the gastric fundus. The lesion was surgically resected.
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With use of the 1-cm wall thickness threshold, the mean wall thickness of the stomach was 1 cm or greater (mean, 2.5 cm; range, 1.2–7.5 cm) in all 14 (100%) cases of malignant or potentially malignant lesions that warranted further diagnostic evaluation (Figs 4–7). Conversely, the mean wall thickness was 1 cm or greater in 14 (58%) (Figs 1–3) and less than 1 cm in 10 (42%) of the 24 cases of benign conditions that warranted no further diagnostic evaluation (mean, 1.0 cm; range, 0.7–2.4 cm). Therefore, the CT finding of a gastric wall thickness of 1 cm or greater had a sensitivity of 100% but a specificity of only 42% in the detection of malignant or potentially malignant stomach lesions.
Further analysis of our study data revealed that the mean wall thickness of the stomach was 2 cm or greater (Figs 6, 7) in seven (50%) and less than 2 cm (Figs 4, 5) in seven (50%) of the 14 cases of malignant or potentially malignant lesions that warranted further diagnostic evaluation. Conversely, the mean wall thickness was 2 cm or greater (Fig 3) in three (12%) and less than 2 cm (Figs 1, 2) in 21 (88%) of the 24 cases of benign conditions that did not warrant further diagnostic evaluation. Therefore, when the threshold for a thickened gastric wall was increased to 2 cm or greater at CT, the specificity of this finding in the detection of malignant or potentially malignant lesions increased to 88%, but the sensitivity decreased to 50%.
The thickened gastric wall had a focal distribution in 13 (93%) (Figs 4–7) and a diffuse distribution in one (7%) of the 14 cases of malignant or potentially malignant lesions. Wall thickening was eccentric or asymmetric in 10 (71%) (Figs 4, 5, 7) and circumferential or symmetric in four (29%) (Fig 6) of the 14 cases of malignant or potentially malignant lesions. After intravenous administration of contrast material, the thickened wall enhanced in six (43%) (Figs 5, 6) but did not enhance in eight (57%) (Figs 4, 7) of the 14 cases of malignant or potentially malignant lesions.
Conversely, the thickened gastric wall had a focal distribution in 22 (92%) (Figs 1–3) and a diffuse distribution in two (8%) of the 24 cases of benign conditions that did not warrant further diagnostic evaluation. Wall thickening was circumferential or symmetric in 18 (75%) of these 24 cases (Fig 1) and eccentric or asymmetric in six (25%) (Figs 2, 3). The thickened wall enhanced after intravenous administration of contrast material in three (12%) of these 24 cases but did not enhance in 21 (88%) (Figs 1 –3). Thus, the finding of focal, eccentric, or enhancing wall thickening had a sensitivity of 93%, 71%, or 43%, respectively, and a specificity of 8%, 75%, or 88%, respectively, in the detection of malignant or potentially malignant stomach lesions.
Gastric wall thickening that was 1 cm or greater, focal, eccentric, and enhancing had a specificity of 92% (22 of 24 cases) but a sensitivity of only 36% (five of 14 cases) in the detection of malignant or potentially malignant lesions at CT (Figs 5, 6).
Four patients had wall thickening in the gastric fundus that resulted from an incompletely distended hiatal hernia (Fig 3). The mean wall thickness in these cases was 1.4 cm (range, 0.7–2.0 cm). The thickened wall enhanced after intravenous administration of contrast material in three (75%) of these four cases.
All three patients with benign conditions in whom the thickened gastric wall enhanced after intravenous administration of contrast material were found to have hiatal hernias. Thus, the presence of a thickened gastric wall that enhanced after intravenous administration of contrast material had an overall specificity of 88% in the detection of malignant or potentially malignant stomach lesions at CT, but the specificity increased to 100% when the cases of hiatal hernia were excluded.
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DISCUSSION
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Because abdominal CT is being performed with greater frequency, it is increasingly becoming possible to detect a variety of abnormalities in the stomach of both symptomatic and asymptomatic patients who have gastric disease. The challenge for radiologists when interpreting these CT images is to differentiate a normal stomach or gastritis from malignant or potentially malignant lesions such as gastric ulcers and neoplasms that warrant further investigation with double-contrast UGI tract or endoscopic examinations. Oral contrast material or effervescent agents can be used to improve gastric distention, and, in questionable cases, supplemental CT can be performed with the patient in the prone position to better evaluate the proximal portion of the stomach. Ultimately, however, radiologists must decide which patients require further diagnostic evaluation to rule out neoplastic lesions in the stomach.
In our study, the primary CT finding in patients with suspected abnormalities of the stomach was a thickened gastric wall. A wall thickness of 1 cm or greater as the threshold criterion had a sensitivity of 100% in the detection of malignant or potentially malignant gastric lesions that warranted further diagnostic evaluation with barium or endoscopic examinations. A wall thickness of 1 cm or greater has also been used as the threshold criterion for the presence of malignant tumor at CT in other studies (1,2). In our study, however, this threshold had a specificity of only 42%, so unnecessary endoscopic or barium examinations were performed in 58% of patients with gastric wall thickening of 1 cm or greater at CT. When the threshold for malignant tumor was increased to 2 cm or greater at CT, the specificity of this finding increased to 88% but the sensitivity decreased to 50%. Thus, no single threshold enabled gastric wall thickness to be both a sensitive and a specific criterion for the detection of malignant or potentially malignant stomach lesions at CT.
In the patients with a gastric wall thickness of 1 cm or greater, the additional CT finding of focal, eccentric, or enhancing wall thickening had a sensitivity of 93%, 71%, or 43%, respectively, and a specificity of 8%, 75%, or 88%, respectively, in the detection of malignant or potentially malignant stomach lesions. Thus, focal wall thickening was a sensitive but very nonspecific CT finding, whereas eccentric wall thickening and enhancing wall thickening were more specific but considerably less sensitive CT findings in the detection of these lesions.
Although no individual CT finding was both sensitive and specific for the detection of malignant stomach lesions, the presence of a gastric wall that was 1 cm or greater in thickness, focal, eccentric, and enhancing after intravenous administration of contrast material had a specificity of 92% in the detection of these lesions (Figs 5, 6). Therefore, this combination of findings at CT should be highly suggestive of malignant tumor, necessitating further evaluation with barium or endoscopic examinations for a definitive diagnosis. Nevertheless, such an appearance of the thickened gastric wall was present at CT in only 36% of patients with malignant tumors in the stomach, limiting the utility of CT for this constellation of findings.
Particular diagnostic difficulties were encountered at CT in four patients with hiatal hernias: Incomplete filling of the hernia created an erroneous impression of gastric wall thickening in the region of the gastric fundus. This so-called pseudotumor at the gastroesophageal junction has been well documented at CT in patients with hiatal hernias (9,10). In such cases, performing CT in patients in the prone position may be helpful for improving the gaseous distention of the fundus and differentiating a pseudotumor caused by a partially collapsed hiatal hernia from a true neoplastic lesion in this region.
Our study was limited by the fact that the primary inclusion criterion was an abnormally thickened gastric wall at CT. As a result, we have no way of knowing how many patients with benign or malignant stomach lesions had no evidence of gastric wall thickening at CT. Also, because this was a retrospective study, there was no set protocol for performing CT in patients in the prone position to optimize the gaseous distention in the proximal portion of the stomach. An erroneous impression of gastric wall thickening at CT can also result from inadequate distention by the oral contrast material or effervescent agent (11,12). Because of this problem, we excluded those cases in which the stomach was inadequately distended at CT to minimize the number of false-positive cases related to technical artifacts. In general, however, additional oral contrast material or effervescent agent should be administered when the assessment of gastric wall thickness is compromised by inadequate gastric distention in patients with signs or symptoms of gastric disease. Because of the limitations of our study, we believe that additional prospective studies to further delineate the CT findings of benign versus malignant conditions of the stomach are warranted (13).
In conclusion, a gastric wall thickness of 1 cm or greater at CT had a sensitivity of 100% but a specificity of less than 50% in the detection of malignant or potentially malignant stomach lesions that warranted further diagnostic evaluation. Focal wall thickening was found to be a sensitive but very nonspecific CT criterion for assessing the malignancy potential of a thickened gastric wall, whereas eccentric wall thickening and enhancing wall thickening were found to be more specific but considerably less sensitive criteria. Wall thickening that was focal, eccentric, and enhancing almost always indicated malignant tumor, but this constellation of findings was present in only a small percentage of cases. Radiologists should be aware of the usefulness of these specific criteria in the evaluation of gastric wall thickening at CT to better differentiate gastritis or a normal stomach from malignant or potentially malignant lesions that warrant further diagnostic evaluation with barium or endoscopic examinations.
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FOOTNOTES
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2 Current address: Department of Radiology, New York University Medical Center, New York, NY. 
Abbreviation: UGI = upper gastrointestinal
Author contributions: Guarantor of integrity of entire study, E.K.I.; study concepts and design, all authors; literature research, E.K.I.; clinical studies, B.A.B., J.E.J.; data acquisition, all authors; data analysis/interpretation, E.K.I., M.S.L.; statistical analysis, E.K.I.; manuscript preparation, definition of intellectual content, and editing, E.K.I., M.S.L.; manuscript revision/review and final version approval, all authors.
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ABSTRACT
INTRODUCTION
