Diagnostic performance of virtual gastroscopy using MDCT in early gastric cancer compared with 2D axial CT: focusing on interobserver variation

Utility of the gastric window in computed tomography for differentiation of early gastric cancer (T1 stage) from muscularis involvement (T2 stage)

OBJECTIVE

To analyze the diagnostic value of using the gastric window in computed tomography for differentiation of early gastric cancer (T1 stage) from muscularis involvement (T2 stage).

MATERIALS AND METHODS

All patients with pathologically confirmed T1 stage and T2 stage gastric cancer and who underwent endoscopic resection or gastrectomy at our institution from January 2011 to November 2018 were examined. Each patient received an enhanced CT scan of the abdomen before the operation. T staging of tumors based on the CT scans was performed independently by two radiologists using the gastric window (width 150-200 HU, level 80-100 HU) and the abdominal window (width 350-400 HU, level 50 HU).

RESULTS

Use of the gastric window to diagnose stage T1 EGC led to an accuracy of 88.9% for observer1 and 91.5% for observer2; use of the abdominal window led to an accuracy of 53.6% for observer1 and 51.6% (38/106) for observer2. Use of the gastric window to diagnose stage T2 led to an accuracy of 85.6% for observer1 and 82.4% for observer2; use of the abdominal window led to an accuracy of 52.3% for both observer1 and observer2. For observer1, use of the gastric window had a diagnostic accuracy of 69.2% for stage T1a and 62.5% for stage T1b; for observer2, the diagnostic accuracy was 65.1% for stage T1a and 67.0% for stage T1b. A Kappa test indicated moderate and substantial inter-observer agreement for T staging with gastric window (κ = 0.598, P < 0.001) and abdominal window (κ = 0.745, P < 0.001).

CONCLUSION

Use of the gastric window in computed tomography provided more accurate staging for T1 and T2 stages of gastric cancer than the conventional abdominal window.

Robotic wedge resection of a rare gastric perivascular epithelioid cell tumor: A case report

BACKGROUND

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm that can arise in many different organs with a broad spectrum of biological behavior, from indolent to aggressive progression. Only ten cases of gastric PEComas have been reported in the English literature, which were treated with endoscopic, laparoscopic, or open resections. Due to its rarity, the optimal surgical management and prognosis of this tumor are still uncertain.

CASE SUMMARY

We present a case of robotic wedge resection of a 6.5 cm bleeding lesion of the gastric fundus located 3 cm below the esophago-gastric junction in a 55-year-old man. Biopsy revealed a malignant tumor with epithelioid cells focally positive for muscle markers desmin and smooth muscle actin. In addition, histology revealed that the tumor was positive for HMB-45, melan-A (MART-1), microphthalmia transcription factor and negative for pan-cytokeratin AE1/AE3, CD34, p40, DOG-1, CD117 (c-kit), S100, CD3, CD79a, caldesmon and myogenin. These markers suggested the possibility of a PEComa. The patient underwent a diagnostic laparoscopy via the da Vinci® Si™ system and robotic wedge resection. Final pathology confirmed a malignant gastric PEComa with negative margins. At his 11-mo follow-up visit, the patient remained disease-free.

CONCLUSION

Gastric PEComa can be treated with a robotic R0 resection with acceptable postoperative and short-term oncological outcomes.

Computed tomography with a stomach protocol and virtual gastroscopy in the staging of gastric cancer: an initial experience

Objective

To evaluate the accuracy of multidetector computed tomography with a stomach protocol in staging of gastric cancer.

Materials and Methods

We evaluated 14 patients who underwent computed tomography in a 16-channel scanner for preoperative staging of gastric adenocarcinoma between September 2015 and December 2016. All images were analyzed by the same radiologist, who had extensive experience in abdominal cancer imaging. The sensitivity, specificity, and accuracy of the method were calculated by comparing it with the pathology result. All patients underwent partial or total gastrectomy.

Results

The mean age was 61.5 years, and 53.8% of the patients were male. The gastric lesions were classified as T1/T2 in 35.7% of the cases, as T3 in 28.5%, and as T4 in 35.7%. Eleven patients (68.7%) had suspicious (N positive) lymph nodes. The accuracy of the T1/T2, T3, T4, and lymph node staging tests was 85%, 78%, 90%, and 78%, respectively. The respective sensitivity and specificity values were 71% and 100% for T1/T2, 66% and 81% for T3, 100% and 90% for T4, and 88% and 60% for lymph nodes.

Conclusion

Multidetector computed tomography with a stomach protocol, used in conjunction with virtual gastroscopy, shows good accuracy in the tumor and lymph node staging of gastric adenocarcinoma.

Comparison between CT Net enhancement and PET/CT SUV for N staging of gastric cancer: A case series

BACKGROUND

The therapeutic approach of gastric cancer strictly depends on TNM staging mainly provided by CT and PET/CT. However, the lymph node size criterion as detected by MDCT causes a poor differential diagnosis between reactive and metastatic enlarged lymph nodes with low specificity values. Our study aims to compare 320-row CT Net enhancement and fluorine-18 fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (F-FDG PET/CT) SUV for N staging of gastric cancer.

MATERIALS AND METHODS

45 patients with histologically proven gastric cancer underwent CT and F-FDG PET/CT. Two radiologists in consensus evaluated all images and calculated the CT Net enhancement and F-FDG PET/CT SUV for N staging, having the histological findings as the reference standard. CT and F-FDG PET/CT sensitivity, specificity, diagnostic accuracy, positive and negative predictive values (PPV and NPV) were evaluated and compared by using the Mc Nemar test.

RESULTS

The histological examination revealed nodal metastases in 29/45 cases (64%). CT Net enhancement obtained sensitivity, specificity, accuracy, PPV and NPV of 90%, 81%, 87%, 90% and 81%, respectively. F-FDG PET/CT SUV obtained sensitivity, specificity, accuracy, PPV and NPV of 66%, 88%, 73%, 90% and 58%, respectively. No statistically significant difference between the two imaging modalities was found (p = 0.1).

CONCLUSION

CT Net enhancement represents an accurate tool for N staging of gastric cancer and could be considered as the CT corresponding quantitative parameter of F-FDG PET/CT SUV. It could be applied in the clinical practice for differentiating reactive lymph nodes from metastatic ones improving accuracy and specificity of CT.

Usefulness of conventional and low-dose hydro-CT in the diagnosis of gastric tumors in comparison to endoscopy

PURPOSE

The aim of this retrospective study was to evaluate the usefulness of hydro-CT in the diagnosis of gastric tumors in comparison to endoscopy.

MATERIAL AND METHODS

The study involved 40 patients with a diagnosis of gastric tumor established by histopathology who underwent endoscopy and conventional or low-dose hydro-CT. Hydro-CT images were retrospectively analyzed based on the consensus of two radiologists who were blinded to the endoscopy findings. The diagnostic accuracy of hydro-CT and endoscopy for the diagnosis of gastric tumors was evaluated using the results of the histopathological examination as the reference standard.

RESULTS

Histopathology confirmed the presence of gastric cancer in 28 patients (70%), while gastrointestinal stromal tumors (GISTs) were recognized in the remaining 12 cases (30%). Correct diagnoses of the type of gastric tumor in hydro-CT were obtained in 37 patients (92.5%). This was not significantly different from the 85% accuracy of endoscopy. Further analysis showed that the correctness of GIST diagnosis in endoscopy and hydro-CT also did not differ significantly (91.7% and 100% respectively). The percentage of correctly diagnosed malignant lesions in hydro-CT was lower than for GISTs at 89.29%, while in endoscopy it was insignificantly lower (82.14%). The diagnostic accuracy of conventional and low-dose hydro-CT in the diagnosis of gastric tumors (95% and 90% respectively) was not significantly different.

CONCLUSIONS

Conventional and low-dose hydro-CT may be a valuable non-invasive diagnostic method in the diagnosis of gastric tumors for patients who have contraindications to endoscopy or who are unable to undergo gastric biopsy.

Differentiating malignant from benign gastric mucosal lesions with quantitative analysis in dual energy spectral computed tomography: Initial experience

To investigate the value of quantitative analysis in dual energy spectral computed tomography (DESCT) for differentiating malignant gastric mucosal lesions from benign gastric mucosal lesions (including gastric inflammation [GI] and normal gastric mucosa [NGM]). This study was approved by the ethics committee, and all patients provided written informed consent. A total of 161 consecutive patients (63 with gastric cancer [GC], 48 with GI, and 50 with NGM) who underwent dual-phase contrast enhanced DESCT scans in the arterial phase (AP) and portal venous phase (PVP) were included in this study. Iodine concentration (IC) in lesions was derived from the iodine-based material-decomposition images and normalized to that in the aorta to obtain normalized IC (nIC). The ratios of IC and nIC between the AP and PVP were calculated. Diagnostic confidence for GC and GI was evaluated with reviewing the features including gastric wall thickness, focal, and eccentric on the conventional polychromatic images. All statistical analyses were performed by using statistical software SPSS 17.0 (SPSS, Chicago, IL). IC and nIC in GC differed significantly from those in GI and NGM, except for nICAP in comparing GC with GI. Mean nIC values of GC (0.18 ± 0.06 in AP and 0.62 ± 0.16 in PVP) were significantly higher than that of NGM (0.12 ± 0.03 in AP and 0.37 ± 0.08 in PVP) (all P < 0.05). There was also significant difference for IC values in GC, GI, and NGM (24.19 ± 8.27, 19.07 ± 5.82, and 13.61 ± 2.52 mg/mL, respectively, in AP and 28.00 ± 7.01, 24.66 ± 6.55, and 16.94 ± 3.06 mg/mL, respectively, in PVP). Based on Receiver Operating Characteristic Curve analysis, nIC and IC in PVP had high sensitivities of 88.89% and 90.48%, respectively, in differentiating GC from NGM, while the sensitivities were 71.43% and 88.89% during AP. Ratios IC and nIC ratios did not provide adequate diagnostic accuracy with their area under curves less than 0.65. With the conventional features, the diagnostic accuracies for GC and GI were 75.0% and 98.0%, respectively. Quantitative analysis of DESCT imaging parameters for gastric mucosa, such as nIC and IC, is useful for differentiating malignant from benign gastric mucosal lesions.

The role of three-dimensional multidetector CT gastrography in the preoperative imaging of stomach cancer: emphasis on detection and localization of the tumor

Multidetector CT (MDCT) gastrography has been regarded as a promising technique for the preoperative imaging of gastric cancer. It has the ability to produce various three-dimensional (3D) images. Because 3D reconstruction images are more effective and intuitive for recognizing abnormal changes in the gastric folds and subtle mucosal nodularity than two-dimensional images, 3D MDCT gastrography can enhance the detection rate of early gastric cancer, which, in turn, contributes to the improvement of the accuracy of preoperative tumor (T) staging. In addition, shaded surface display and tissue transition projection images provide a global view of the stomach, with the exact location of gastric cancer, which may replace the need for barium studies. In this article, we discuss technical factors in producing high-quality MDCT gastrographic images and present cases demonstrating the usefulness of MDCT gastrography for the detection and T staging of gastric cancer while emphasizing the significance of preoperative localization of gastric cancer in terms of surgical margin.

State-of-the-art preoperative staging of gastric cancer by MDCT and magnetic resonance imaging

Gastric cancer is one of the most common and fatal cancers. The importance of accurate staging for gastric cancer has become more critical due to the recent introduction of less invasive treatment options, such as endoscopic mucosal resection or laparoscopic surgery. The tumor-node-metastasis staging system is the generally accepted staging system for predicting the prognosis of patients with gastric cancer. Multidetector row computed tomography (MDCT) is a widely accepted imaging modality for the preoperative staging of gastric cancer that can simultaneously assess locoregional staging, including the gastric mass, regional lymph nodes, and distant metastasis. The diagnostic performance of MDCT for T- and N-staging has been improved by the technical development of isotropic imaging and 3D reformation. Although magnetic resonance imaging (MRI) was not previously used to evaluate gastric cancer due to the modality’s limitations, the development of high-speed sequences has made MRI a feasible tool for the staging of gastric cancer.

Gastric cancer: imaging and staging with MDCT based on the 7th AJCC guidelines

Gastric cancer is a common deadly cancer worldwide. The tumor-node-metastasis (TNM) staging system is one of the most commonly used staging systems, and is accepted and maintained by the International Union against Cancer (UICC) and the American Joint Committee on Cancer (AJCC). The TNM system is well known to effectively predict the prognosis of gastric cancer patients. The latest revision of TNM staging was presented in the 7th edition of the AJCC in 2009. Multi-detector row CT (MDCT) is a powerful test for non-invasive evaluation and can assess metastatic and locoregional staging simultaneously. Current MDCT with isotropic imaging and 3D images has increased the accuracy of T and N staging in patients with gastric cancer. Multi-planar reformatted images permit the radiologist to select the optimal imaging plane to accurately evaluate tumor invasion depth of the gastric wall and perigastric infiltration to identify a fat plane between a tumor and adjacent organs, to avoid partial volume averaging effects, and to differentiate lymph nodes from small perigastric vessels. Thus, MDCT provides a useful all-in-one diagnostic method for the pre-operative evaluation of patients with known, or strongly suspected, gastric cancer according to the 7th AJCC TNM staging system.

Gastric cancer detection using MDCT compared with 2D axial CT: diagnostic accuracy of three different reconstruction techniques

PURPOSE

To assess the diagnostic accuracy of different reconstruction techniques using MDCT for gastric cancer detection compared with 2D axial CT.

MATERIALS AND METHODS

During 7 months, we performed CT examinations of 104 consecutive patients with gastric cancer and of a control group composed of 35 patients without gastric disease. All gastric cancer was pathologically proven by endoscopy and surgery. Among 104 patients with gastric cancer, 63 patients had early gastric cancer (EGC). Two radiologists retrospectively and independently interpreted the axial CT and three different reconstruction techniques including multiplanar reformation (MPR), transparent imaging (TI), and virtual gastroscopy (VG), using a commercially available, 3D workstation. They graded the presence or absence of gastric cancer in each image sets using a five-point scale and, if present, they assessed its location. Diagnostic accuracy was compared using the area under the receiver operating characteristic curve (Az) for both gastric cancer and only EGC. Sensitivity and specificity were also calculated for each image technique. The k statistics were used to determine inter-observer agreement.

RESULTS

The diagnostic accuracy for overall gastric cancer detection for each of the image sets was as follows: 2D axial CT (Az = 0.858); MPR (Az = 0.879); TI (Az = 0.873); and VG (Az = 0.928). VG had significantly better performance than 2D axial CT (p = 0.016). The sensitivity and specificity were as follows: 76.7% and 82.9% in axial CT; 79.6% and 85.7% in MPR; 91.3% and 80% in TI; and 95.1% and 74.3% in VG. In EGC, the diagnostic performance for its detection was as follows: axial CT (Az = 0.777); MPR (Az = 0.811); TI (Az = 0.825); and VG (Az = 0.896). VG had significantly better performance than both 2D axial CT (P = 0.006) and MRP (P = 0.038). The sensitivity and specificity were as follows: 62.9% and 82.9% in axial CT; 67.7% and 85.7% in MPR; 85.5% and 80% in TI; and 91.9% and 74.3% in VG. The inter-observer agreement showed substantial agreement (κ = 0.67-0.75).

CONCLUSION

Among the different reconstruction techniques, VG accurately detects gastric cancer and is especially useful for EGC compared with 2D axial CT.

Can computed tomographic gastrography and multiplanar reformatting aid the laparoscopic surgeon in planning a gastric resection? A pictorial essay

PURPOSE

To assess the value and feasibility of computed tomographic gastrography and multiplanar reformatting in the preoperative evaluation of patients undergoing laparoscopic gastric resection.

MATERIALS AND METHODS

Fourteen patients with gastric lesions were included in the study. A supine scan was performed after a hypotonic drug, an effervescent agent, and intravenous contrast. This was followed by delayed prone and decubitus scans. We created multiplanar reformats, transparency rendered images, and endoluminal images. The tumours were localized, and distances were measured to the esophagogastric junction and the pylorus.

RESULTS

Eleven patients underwent resections. Seven had laparoscopic wedge resections for aberrant pancreas (1 patient), carcinoid (1), Castleman disease (1), and gastrointestinal stromal tumours (GISTs) (4). One patient had an open subtotal gastrectomy for carcinoma due to adhesions. One had a hand-assisted sleeve resection for a gastrointestinal stromal tumour. Two had hand-assisted total gastrectomies for carcinoma and a GIST. For surgical planning, the surgeon rated the imaging extremely useful in 7 and useful in 4. Imaging was extremely useful or useful to localize laparoscopically invisible tumours in 6 patients and to relate tumours to the esophagogastric junction or pylorus and to assess localized vs extensive resection in 8. Correlation was excellent between the preoperative imaging and the intraoperative findings.

CONCLUSIONS

Computed tomographic gastrography and multiplanar reformatting are useful aids in preoperative planning of laparoscopic gastric resections.

Diagnosis of the invasion depth of gastric cancer using MDCT with virtual gastroscopy: comparison with staging with endoscopic ultrasound

OBJECTIVE

The objectives of this study were to retrospectively evaluate the lesion detection rate of gastric cancer using only virtual gastroscopy generated from MDCT images and the accuracy of invasion depth diagnosis (T staging) using virtual gastroscopy together with contrast-enhanced MDCT with multiplanar reconstruction (MPR) images (virtual gastroscopy with MPR), and to compare the diagnostic performance between virtual gastroscopy with MPR images and endoscopic ultrasound.

MATERIALS AND METHODS

The subjects consisted of 175 patients with a total of 186 endoscopically proven gastric cancer lesions. All patients underwent dynamic MDCT (arterial and venous phase) for preoperative staging and underwent surgery or endoscopic treatment. In 129 patients (135 lesions) who were also examined using endoscopic ultrasound, the T staging accuracy was also compared between the two modalities. Two endoscopists independently evaluated the lesion detection rate on virtual gastroscopy images alone and determined the T stage on virtual gastroscopy with MPR images. The T staging included the ability to differentiate T1a from T1b lesions.

RESULTS

The overall lesion detection rate was 67.7% (126/186). The detection rates of T1a, T1b, and T2 or deeper were 37.8% (28/74), 75.0% (39/52), and 98.3% (59/60), respectively, showing statistically significant differences (p < 0.001). The T staging accuracies were 82.2% (111/135) using virtual gastroscopy with MPR images and 83.7% (113/135) using endoscopic ultrasound, showing no statistically significant difference (p = 0.850). The main causes of over- and understaging were an ulcer or ulcer scar and poorly differentiated adenocarcinomas, non-solid type, respectively.

CONCLUSION

Virtual gastroscopy with MPR imaging is a useful modality in the T staging of gastric cancer.

Diagnostic performance of 64-section CT using CT gastrography in preoperative T staging of gastric cancer according to 7th edition of AJCC cancer staging manual

OBJECTIVES

To evaluate the accuracy of 64-section multidetector CT with CT gastrography for determining the depth of mural invasion in patients with gastric cancer according to the 7th edition of the AJCC cancer staging manual.

METHODS

A total of 127 patients with gastric cancer and who had undergone both esophago-gastro-duodenoscopy and 64-section CT were included in this study. Two radiologists independently reviewed the preoperative CT images with respect to the detectability and T-staging of the gastric cancers. The sensitivity, specificity, accuracy and overall accuracy of each reviewer for the T staging of gastric cancer were calculated.

RESULTS

Overall, gastric cancer was detected in 123 (96.9%) of the 127 cancers on the CT images. Reviewer 1 correctly staged 98 gastric cancers, and reviewer 2 correctly classified 105 gastric cancers. The overall diagnostic accuracy of the T staging was 77.2% (98/127) for reviewer 1 and 82.7% (105/127) for reviewer 2.

CONCLUSION

64-section CT using CT gastrography showed a reasonable diagnostic performance for determining the T staging in patients with gastric cancer according to the 7th edition of the AJCC cancer staging manual.

KEY POINTS

64-section CT is useful for determining the T staging of gastric cancer Virtual gastroscopy is helpful for detecting early gastric cancer New CT criteria may be applicable to the T staging The normal gastric wall frequently shows a multilayered pattern.

Serum pepsinogen II: a neglected but useful biomarker to differentiate between diseased and normal stomachs

BACKGROUND AND AIM

Serum pepsinogen II (sPGII) is underutilized and considered an inconspicuous biomarker in clinical practice. We refocused on this neglected but novel biomarker and conducted the present study, aiming to elucidate the normal level of sPGII in healthy Chinese patients and to investigate the clinical utility of sPGII for gastric disease screening.

METHODS

In 2008-2009, a total of 2022 participants from northern China were selected and enrolled in the study. sPGII and Helicobacter pylori (H. pylori)-immunoglobulin G were measured with ELISA.

RESULTS

sPGII showed a normal value of 6.6 microg/L in a total of 466 patients with endoscopically- and histologically-normal stomachs. A small sex difference was observed: the average value of sPGII was 7 microg/L and 6 microg/L in males and females, respectively (P < 0.001). In the differentiation between healthy and diseased (endoscopically-diseased stomach or gastritis/atrophic gastritis in endoscopic biopsies) stomach mucosae, the best sPGII cut-off value was 8.25 microg/L (sensitivity 70.6%, specificity 70.8%). In screening the H. pylori seropositivity, the optimum cut-off sPGII value was 10.25 microg/L (sensitivity 71.6%, specificity 70.1%).

CONCLUSIONS

We demonstrated that the mean values of sPGII in a healthy Chinese population are 7 microg/L and 6 microg/L for males and females, respectively. sPGII significantly increases in diseased and H. pylori-infected stomach, and the best sPGII cut-off value is 8.25 microg/L in the differentiation between patients with healthy and diseased stomach mucosae. Furthermore, Chinese patients with sPGII greater than 10.25 microg/L are at greater risk of various H. pylori-related gastropathies, and are therefore prior candidates for gastro-protection therapy.

Detection of early gastric cancer using hydro-stomach CT: Blinded vs unblinded analysis

AIM: To evaluate the difference in diagnostic performance of hydro-stomach computed tomography (CT) to detect early gastric cancer (EGC) between blinded and unblinded analysis and to assess independent factors affecting visibility of cancer foci.

METHODS: Two radiologists initially blinded and then unblinded to gastroscopic and surgical-histological findings independently reviewed hydro-stomach CT images of 110 patients with single EGC. They graded the visibility of cancer foci for each of three gastric segments (upper, middle and lower thirds) using a 4-point scale (1: definitely absent, 2: probably absent, 3: probably present, and 4: definitely present). The sensitivity and specificity for detecting an EGC were calculated. Intraobserver and interobserver agreements were analyzed. The visibility of an EGC was evaluated with regard to tumor size, invasion depth, gastric segments, histological type and gross morphology using univariate and multivariate analysis.

RESULTS: The respective sensitivities and specificities [reviewer 1: blinded, 20% (22/110) and 98% (215/220); unblinded, 27% (30/110) and 100% (219/220)/reviewer 2: blinded, 19% (21/110) and 98% (216/220); unblinded, 25% (27/110) and 98% (215/220)] were not significantly different. Although intraobserver agreements were good (weighted κ = 0.677 and 0.666), interobserver agreements were fair (blinded, 0.371) or moderate (unblinded, 0.558). For both univariate and multivariate analyses, the tumor size and invasion depth were statistically significant factors affecting visibility.

CONCLUSION: The diagnostic performance of hydro-stomach CT to detect an EGC was not significantly different between blinded and unblinded analysis. The tumor size and invasion depth were independent factors for visibility.

Comparison between blinded and partially blinded detection of gastric cancer with multidetector CT using surgery and endoscopic submucosal dissection as reference standards

The aim of this study is to compare blinded with partially blinded detection of gastric cancer with multidetector (MD) CT by using surgery and endoscopic submucosal dissection (ESD) as reference standards. 44 patients with gastric cancer underwent MDCT with air as an oral contrast agent. Surgery was performed on 37 patients, ESD on six and surgery after ESD on one. To provide comparison cases of blinded evaluation, 38 MDCT examinations were added for cases where no focal gastric lesion was seen on endoscopy. Two radiologists, blinded to the presence, number and location of the tumours, evaluated axial and axial plus multiplanar reformation (MPR) images of 82 MDCT examinations with or without gastric cancer. For partially blinded evaluation, the same radiologists, blinded to the location and number of tumours, evaluated axial and axial plus MPR images of 44 MDCT examinations of gastric cancer. Differences in assessment were resolved by consensus. 45 gastric cancers were found in surgical and ESD specimens. Detection rates of gastric cancer from axial and axial plus MPR images during blinded evaluation and from axial and axial plus MPR images during partially blinded evaluation were 62% (28/45), 64% (29/45), 64% (29/45) and 71% (32/45), respectively. There was no statistical significance for the comparison between blinded and partially blinded detection rates of gastric cancer. The detection rate of gastric cancer with MDCT during blinded evaluation showed no specific difference compared with the detection rate of gastric cancer with MDCT during partially blinded evaluation.

Value of multidetector-row computed tomography in the preoperative T and N staging of gastric carcinoma: a large-scale Chinese study

OBJECTIVES

To investigate the value of multidetector-row computed tomography (MDCT) in the preoperative T and N staging of gastric carcinoma and to further investigate the clinicopathological factors affecting the diagnostic accuracy.

METHODS

Seven hundred ninety gastric carcinoma patients underwent preoperative MDCT examination. The results of MDCT were compared with surgical and pathological findings.

RESULTS

Early gastric carcinoma patients whose primary tumor was detected by MDCT had higher incidence of lymph node metastasis, larger tumor size, and deeper invasion. The overall accuracy of MDCT in determining T stage of gastric carcinoma was 73.80% (T1 45.93%, T2 53.03%, T3 86.49%, and T4 85.79%). The overall accuracy of MDCT in preoperative N staging was 75.22% (N0 76.17%, N1 68.81%, and N2 80.63%). The overall diagnostic sensitivity, specificity, and accuracy of MDCT for determining lymph node metastasis was 86.26%, 76.17%, and 82.09%, respectively. Multivariate analysis showed that the diagnostic sensitivity of MDCT in determining lymph node metastasis related with tumor size, N stage, and number of metastatic lymph nodes.

CONCLUSIONS

The clinical value of MDCT in the preoperative T and N staging of gastric carcinoma is relatively high. MDCT can be the first choice for the preoperative evaluation of patients with gastric carcinoma.

Preoperative T staging of gastric carcinoma obtained by MDCT vessel probe reconstructions and correlations with histological findings

This study aims to evaluate the diagnostic accuracy of 16-row multidetector CT (MDCT) and vessel probe reconstructions in the T staging of gastric carcinoma. Fifty-three patients (39 men, 14 women, mean age 57.5) with an endoscopic diagnosis of gastric adenocarcinoma underwent CT examination. A hypotonic drug was administered, and the gastric walls were distended by the ingestion of 400-600 ml of water. A biphasic technique with 40-s and 70-s delay was used after endovenous contrast material injection. All patients underwent surgery, and preoperative and histological stagings were compared. The diagnostic accuracy of T staging was 68% for axial images and 94% for VP reconstructions. In the T1, T2, T3 and T4 parameter evaluation, diagnostic accuracy values were 87%, 73.5%, 81% and 96%, respectively, for axial images and 96%, 96%, 98% and 100%, respectively for VP reconstructions. MDCT is an accurate technique for the preoperative staging of gastric cancer. The VP reconstructions obtained by isotropic data can evaluate the T parameter with a higher accuracy.

Positioning during CT gastrography in patients with gastric cancer: the effect on gastric distension and lesion conspicuity

OBJECTIVE

We wanted to prospectively evaluate the effect of various positions of the patient on gastric distension and lesion conspicuity during performance of CT gastrography (CTG).

MATERIALS AND METHODS

One hundred thirteen consecutive patients with gastric cancer underwent CTG in the 30 degrees left posterior oblique (LPO), supine, and prone positions. Two radiologists scored (a grade from 1-4) the degree of gastric distension and the lesion conspicuity according to the three scanning positions and the three gastric portions. Two- (2D) and three-dimensional (3D) images were used for analysis. Finally, these data were compared with the endoscopic findings and surgical results.

RESULTS

The mean scores of gastric distension and lesion conspicuity for the LPO and supine positions were higher than those for the prone position (p < 0.001) in the gastric middle and lower portions. However, there was no significant difference between the LPO and supine positions (p > or = 0.21). As for the gastric upper portion, the mean scores of gastric distension in the prone position were higher than those in the two other positions (p < 0.001). The prone position showed better lesion conspicuity than the two other positions for only one of two cases of gastric cancer in the upper portion of the stomach.

CONCLUSION

CTG performed in the LPO position or the supine position combined with CTG performed in the prone position is optimal for achieving good gastric distension and evaluating the lesion conspicuity of gastric cancer.

Risk factors and multidetector-row computed tomography evaluation of lymph node metastasis in early gastric carcinoma

AIM: To identify the risk factors predicting lymph node metastasis in early gastric carcinoma (EGC) and to investigate the value of multidetector-row computed tomography (MDCT) in the preoperative assessment of lymph node metastasis.

METHODS: Relationship between the clinicopathological parameters and lymph node metastasis in 109 EGC patients (male 64, female 45, mean age 56) who underwent preoperative MDCT examination and curative gastrectomy was retrospectively analyzed. In addition, the results of lymph node status evaluated by MDCT were compared with pathologic findings.

RESULTS: The incidence rate of lymph node metastasis was 15.60% in EGC patients. The incidence of lymph node metastasis in submucosal carcinoma was significantly higher than that in mucosal carcinoma (25.00% vs 9.23%, P = 0.026). However, the lymph node metastasis in EGC was not closely related to the gender, age of patients, tumor size, macroscopic type, tumor location, and histological type. Receiver operating characteristic (ROC) analysis further showed that the accuracy of tumor size for determination of lymph node metastasis in EGC was relatively low (area under ROC curve was 0.63). The overall accuracy of MDCT in preoperative N staging of EGC was 82.6% (N0 85.9%, N1 64.3%, N2 66.7%, respectively). The diagnostic sensitivity, specificity and accuracy of MDCT for determining lymph node metastases of EGC were 70.6%, 85.9%, and 83.5%, respectively. The diagnostic sensitivity of MDCT for determining lymph node metastasis was 50.0% in patients with solitary lymph node metastasis, while 88.89% in those with more than one lymph node metastasis. In 5 EGC patients, the lymph node metastasis was not detected by MDCT. However, the tumor size of all these 5 patients was larger than or equal to 2 cm in diameter, and both of the two mucosal carcinomas belonged to depressed EGC.

CONCLUSION: Although the clinical value of MDCT in the preoperative assessment of lymph node metastasis in patients with EGC is relatively high, we still must pay great attention to the value of lymph node metastasis-associated clinicopathological parameters in predicting lymph node status when the minimally invasive therapy is to be performed for patients with EGC.