Efficacy of helical CT in T-staging of gastric cancer

Imaging in Gastric Cancer: Current Practice and Future Perspectives

Gastric cancer represents one of the most common oncological causes of death worldwide. In order to treat patients in the best possible way, the staging of gastric cancer should be accurate. In this regard, endoscopy ultrasound (EUS) has been considered the reference standard for tumor (T) and nodal (N) statuses in recent decades. However, thanks to technological improvements, computed tomography (CT) has gained an important role, not only in the assessment of distant metastases (M status) but also in T and N staging. In addition, magnetic resonance imaging (MRI) can contribute to the detection and staging of primary gastric tumors thanks to its excellent soft tissue contrast and multiple imaging sequences without radiation-related risks. In addition, MRI can help with the detection of liver metastases, especially small lesions. Finally, positron emission tomography (PET) is still considered a useful diagnostic tool for the staging of gastric cancer patients, with a focus on nodal metastases and peritoneal carcinomatosis. In addition, it may play a role in the treatment of gastric cancer in the coming years thanks to the introduction of new labeling peptides. This review aims to summarize the most common advantages and pitfalls of EUS, CT, MRI and PET in the TNM staging of gastric cancer patients.

Prospective Comparison of Oral Contrast-Enhanced Transabdominal Ultrasound Imaging With Contrast-Enhanced Computed Tomography in Pre-operative Tumor Staging of Gastric Cancer

The aim of this prospective study was to compare the diagnostic accuracy of oral contrast-enhanced transabdominal ultrasound imaging (OCTU) with that of contrast-enhanced computed tomography (CT) for the pre-operative tumor staging of gastric cancer, with post-operative pathology as the standard. We included 108 cases of gastric cancer with simultaneous OCTU and enhanced CT pre-operative tumor staging diagnoses. Results were compared with post-operative pathology based on the eighth edition of the American Joint Committee on Cancer tumor-node-metastasis staging guidelines for gastric cancer. The accuracy of each tumor stage was obtained by comparing OCTU and enhanced CT diagnoses with post-operative pathology. The McNemar test was used to compare the overall accuracy of the two methods. There was no statistical difference in accuracy between OCTU (72.2%) and enhanced CT (75.9%, p = 0.644) for overall pre-operative tumor staging diagnosis. For stages T1 to T4, the accuracy rates of OCTU were 84.2%, 81.8%, 69.4% and 65.5%, respectively, and those for enhanced CT were 52.6%, 72.7%, 87.8% and 72.4%, respectively. OCTU is comparable to enhanced CT in the preoperative overall T-stage diagnosis of gastric cancer.

Gastric hydrodistension CT versus CT without gastric distension in preoperative TN staging of gastric carcinoma: analysis of single-center cancer registry

Accurate staging of gastric cancer is essential for the selection and optimization of therapy. Hydrodistension of the stomach is recommended to improve the accuracy of preoperative staging with contrast-enhanced multidetector computed tomography (MDCT). This study compares the performance of contrast-enhanced gastric water distension versus a nondistension MDCT protocol for T and N staging and serosal invasion in comparison to surgical histopathology. After propensity score matching, 86 patients in each group were included for analysis. The overall accuracy of distension versus nondistension group in T staging was 45% (95% CI 35-56) and 55% (95% CI 44-65), respectively (p = 0.29). There was no difference in the sensitivity and specificity in individual T staging and assessment of serosal invasion (all p > 0.41). Individual stage concordance with pathology was not significantly different (all p > 0.41). The overall accuracy of N staging was the same for distension and nondistension groups (51% [95% CI 40-62]). The majority of N0 staging (78-81%) were correctly staged, whereas N3 staging cases (63-68%) were predominantly understaged. In summary, there was no significant difference in the diagnostic performance of individual TN staging and assessment of serosal invasion using MDCT with or without gastric water distension.

Feasibility of using two-dimensional axial computed tomography in pretreatment decision making for patients with early gastric cancer

Computed tomography (CT) is widely used in the pretreatment period of early gastric cancer (EGC). Only few studies have reported low accuracy of CT imaging for T and N staging in patients with EGC. However, owing to the limited number of studies, the value of CT imaging for EGC staging is not well known. Thus, we conducted a retrospective cross-sectional study regarding the associations among submucosal invasion, lymph node metastasis, and CT findings.The medical records of patients with EGC who had surgery or endoscopic resection were reviewed in a single center from January 2011 to December 2016. We evaluated the histological type, invasion depth, and lymph node (LN) metastasis on the basis of two-dimensional CT findings.We enrolled 1544 patients. Submucosal (SM) invasion was related to tumor size, histological type, and wall thickening or enhancement on CT images. Deep SM invasion (>500 μm) was also related to tumor size, poorly differentiated type, and abnormal CT findings (wall thickening, enhancement, and central depression). Among the patients with LN reactive positivity (0.5-1 cm), those who were female and had a tumor invasion of >1000 μm showed a higher prevalence of LN metastasis. The false-negative LN group had a higher prevalence of large tumors (>3 cm), poor differentiation, and SM invasion than the true-negative group.Wall thickening, enhancement, and central depression on CT images might be related to SM invasion. Patients with any positive CT findings needs more attention when performing ESD.

Effect of the degree of gastric filling on the measured thickness of advanced gastric cancer by computed tomography

Imaging of gastric cancer thickness is closely associated with the depth of tumor invasion, which provides guidance for clinical staging and assists the evaluation of the effects of adjuvant therapy. However, it is unclear whether the measurement of thickness is affected by the degree of gastric filling, and its accuracy and reliability are under-reported. The present study aimed to investigate the influence of the degree of gastric filling on the measurement of gastric cancer thickness. A total of 38 patients with advanced gastric cancer who underwent enhanced abdominal computed tomography (CT) scanning at the Department of CT and MR in The Fourth Hospital of Hebei Medical University (Shijiazhuang, China) between July and September 2016 were recruited, consisting of 21 newly diagnosed cases and 17 follow-up cases following non-surgical treatments. Plain scanning (prior to filling) and enhanced scanning in venous phase (following filling) were performed. Axial CT images prior to and following filling of the normal part of gastric wall and the lesions were compared. The same procedure was repeated on these participants 1 month later by the same radiologist, and the results were compared with those obtained previously. Normal gastric wall thickness prior to and following gastric filling was significantly different (all P<0.001) with the most substantial changes observed at the greater curvature. Lesion thickness prior to and following filling was similar in newly diagnosed patients, but significantly different in patients for re-examination (P<0.05). The two thickness measurements in the same patients were consistent. The measured thickness of gastric cancer in newly diagnosed patients was relatively stable, and could be used as an indicator in baseline CT examination. Maintaining a similar degree of gastric filling during re-examination could aid the accurate evaluation of treatment efficacy.

The Value of Computed Tomography in Preoperative N Staging of Early Gastric Cancer Meeting the Endoscopic Resection Criteria

Background/Aims

This study evaluated the value of abdominal computed tomography (CT) in preoperative N staging of early gastric cancers (EGCs) within standard and expanded indications of endoscopic resection (ER) and investigated the factors affecting accuracy.

Methods

Between March 2009 and March 2016, a total of 268 patients with EGC within the standard and expanded indications of ER underwent preoperative abdominal CT and surgical gastrectomy with lymph node (LN) dissection. Preoperative N staging of CT was compared with the pathologic result.

Results

The accuracy of N staging for EGCs within the standard and expanded indications was 86.1% (235/268). There was no LN metastasis in patients with cN1 in CT staging. LN metastasis was found in 7 patients with EGCs that met the expanded ER indication and cN0 in CT staging. According to the univariate analysis, ulcers, including scars, were associated with the false positive of lymph node metastasis in abdominal CT (odds ratio 3.56; 95% confidence interval 1.56-8.15).

Conclusions

The present study suggests that the value of abdominal CT is limited for nodal staging of EGCs that meet the ER indication.

数字胃肠造影与腹部CT对胃癌的临床诊断

目的

研究数字胃肠造影技术与腹部CT在临床中对胃癌的诊断价值.

方法

选取2015-11/2016-11经天津医科大学宝坻临床学院采用CT和数字胃肠检查胃癌的患者纳入42例, 检查结果均已得到病理学和临床手术证实. 比较两种检查结果并对影像学特点进行分析.

结果

经数字胃肠造影显示42例胃癌患者特征: 胃癌性溃疡3例、胃黏膜皱璧破坏2例、胃腔内充盈缺损6例、胃蠕动减弱消失5例、胃轮廓缩窄变形4例; CT检测显示: 肝脏转移2例、胃腔狭窄2例、胃壁增厚3例、腹水及幽门梗阻6例、胃腔内肿块2例、胃部淋巴结转移和腹部主动脉、肝门区、门腔静脉间隙2例、胰腺转移3例, 增强扫描可见胃壁强化异常2例. 数字胃肠造影特异度为77.50%、灵敏度96.61%, Kappa = 0.768; CT胃癌诊断特异度为72.50%、灵敏度93.22%, Kappa = 0.742; CT与数字胃肠造影均有较高的诊断率.

结论

数字胃肠造影与CT在临床中诊断胃癌各有优势和不足, 但CT对远处脏器转移转移和肿块范围、淋巴结的诊断及手术适应证评估明显优于数字胃肠造影, 两者结合值得临床推广应用.

Endoscopic ultrasonography compared with multidetector computed tomography for the preoperative staging of gastric cancer: a meta-analysis

Background

The current study sought to perform a meta-analysis to compare the preoperative staging of endoscopic ultrasonography (EUS) and multidetector computed tomography (MDCT) in gastric carcinoma.

Methods

Articles published between January 1, 2000, and April 1, 2016, that compared EUS with MDCT were included, and data were presented as 2 × 2 tables. The sensitivities, specificities and summary receiver operating characteristic (ROC) curves for T and N staging were calculated using a bivariate mixed effects model. Data were weighted by generic variance and then pooled by random-effects modeling.

Results

Eight studies comprising 1736 patients were included in this meta-analysis. For T1 staging, the sensitivity value for EUS (82%) was significantly higher than that for MDCT (41%) (relative risk (RR): 2.06, 95% confidence interval (CI) 1.07–3.94; P = 0.030). For lymph node involvement, the sensitivity value for EUS (91%) was also significantly higher than that for MDCT (77%) (RR 1.14, 95% CI 1.05–1.23; P = 0.001). However, the specificity values of both EUS and MDCT were quite low, at 49 and 63%, respectively. No significant differences in T2–4 staging between EUS and MDCT were noted.

Conclusion

This meta-analysis indicates that EUS may be superior to MDCT in preoperative T1 and N staging. Additionally, the low specificity values of EUS and MDCT for N staging merits attention.

CT volumetry for gastric carcinoma: association with TNM stage

OBJECTIVES

We evaluated the feasibility of performing CT volumetry of gastric carcinoma (GC) and its correlation with TNM stage.

METHODS

This institutional review board-approved retrospective study was performed on 153 patients who underwent a staging CT study for histologically confirmed GC. CT volumetry was performed by drawing regions of interest including abnormal thickening of the stomach wall. Reproducibility of tumour volume (Tvol) between two readers was assessed. Correlation between Tvol and TNM/peritoneal staging derived from histology/surgical findings was evaluated using ROC analysis and compared with CT evaluation of TNM/peritoneal staging.

RESULTS

Tvol was successfully performed in all patients. Reproducibility among readers was excellent (r = 0.97; P = 0.0001). The median Tvol of GC showed an incremental trend with T-stage (T1 = 27 ml; T2 = 32 ml; T3 = 53 ml and T4 = 121 ml, P < 0.01). Tvol predicted with good accuracy T-stage (≥T2:0.95; ≥T3:0.89 and T4:0.83, P = 0.0001), M-stage (0.87, P = 0.0001), peritoneal metastases (0.87, P = 0.0001) and final stage (≥stage 2:0.89; ≥stage 3:0.86 and stage 4:0.87, P = 0.0001), with moderate accuracy for N-stage (≥N1:0.75; ≥N2:0.74 and N3:0.75, P = 0.0001). Tvol was significantly (P < 0.05) more accurate than standard CT staging for prediction of T-stage, N3-stage, M-stage and peritoneal metastases.

CONCLUSION

CT volumetry may provide useful adjunct information for preoperative staging of GC.

KEY POINTS

CT volumetry of gastric carcinoma is feasible and reproducible. Tumour volume <19.4 ml predicts T1-stage gastric cancer with 91% sensitivity and 100% specificity (P = 0.0001). Tumour volume >95.7 ml predicts metastatic gastric cancer with 87% sensitivity and 78.5% specificity (P = 0.0001). CT volumetry may be a useful adjunct for staging gastric carcinoma.

[Prognostic value of preoperative positron emission tomography-computed tomography in surgically resected gastric cancer]

BACKGROUND/AIMS

The diagnostic value of PET-CT, in gastric cancer is well known, but the prognostic value of pretreatment PET-CT has not been adequately evaluated. This study aimed to investigate the preoperative prognostic value of PET-CT in gastric cancer patients.

METHODS

A total of 107 patients underwent surgical treatment for gastric cancer from April 2007 to December 2010 at Dong-A University Medical Center after confirming the presence of F-18 fluorodeoxyglucose (FDG) uptake on preoperative PET-CT. Among these patients, the following subjects were excluded: follow-up loss (13), palliative resection (5), neoadjuvant chemotherapy (1), and unrelated death (1). The remaining 87 patients were included in this study and data were collected by retrospectively reviewing the medical records. The median follow-up duration, defined as the period from operation to last imaging study date, was 34.2±14.8 months. FDG uptake values were represented by maximal standardized uptake value (SUVmax). In order to assess the correlation between SUVmax and recurrence, Kaplan-Meier's survival analysis with log-rank test and cox proportional hazard model were performed. Receiver operating characteristic (ROC) curve was employed to determine the optimal cutoff value of SUVmax.

RESULTS

The result of Kaplan-Meier's survival analysis with log-rank test were significantly different between high SUVmax group and low SUVmax group (p=0.035), the cutoff value of which was 5.6. However, in multivariate analysis with cox proportional hazard model, T-staging, N-staging and SUVmax did not show statistical significance (p=0.190, p=0.307, and p=0.436, respectively).

CONCLUSIONS

High SUVmax on PET-CT in gastric cancer can be a useful prognostic factor.

Comparison of endoscopic ultrasonography and multislice spiral computed tomography for the preoperative staging of gastric cancer - results of a single institution study of 610 Chinese patients

BACKGROUND

This study compared the performance of endoscopic ultrasonography (EUS) and multislice spiral computed tomography (MSCT) in the preoperative staging of gastric cancer.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 610 patients participated in this study, all of whom had undergone surgical resection, had confirmed gastric cancer and were evaluated with EUS and MSCT. Tumor staging was evaluated using the Tumor-Node-Metastasis (TNM) staging and Japanese classification. The results from the imaging modalities were compared with the postoperative histopathological outcomes. The overall accuracies of EUS and MSCT for the T staging category were 76.7% and 78.2% (P=0.537), respectively. Stratified analysis revealed that the accuracy of EUS for T1 and T2 staging was significantly higher than that of MSCT (P<0.001 for both) and that the accuracy of MSCT in T3 and T4 staging was significantly higher than that of EUS (P<0.001 and 0.037, respectively). The overall accuracy of MSCT was 67.2% when using the 13th edition Japanese classification, and this percentage was significantly higher than the accuracy of EUS (49.3%) and MSCT (44.6%) when using the 6th edition UICC classification (P<0.001 for both values).

CONCLUSIONS/SIGNIFICANCE

Our results demonstrated that the overall accuracies of EUS and MSCT for preoperative staging were not significantly different. We suggest that a combination of EUS and MSCT is required for preoperative evaluation of TNM staging.

Gastric carcinoma: imaging diagnosis, staging and assessment of treatment response

Gastric carcinoma (GC) is one of the most common causes of cancer-related death worldwide. Surgical resection is the only cure available and is dependent on the GC stage at presentation, which incorporates depth of tumor invasion, extent of lymph node and distant metastases. Accurate preoperative staging is therefore essential for optimal surgical management with consideration of preoperative and/or postoperative chemotherapy. Multidetector computed tomography (MDCT) with its ability to assess tumor depth, nodal disease and metastases is the preferred technique for staging GC. Endoscopic ultrasonography is more accurate for assessing the depth of wall invasion in early cancer, but is limited in the assessment of advanced local or stenotic cancer and detection of distant metastases. Magnetic resonance imaging (MRI), although useful for staging, is not proven to be effective. Positron emission tomography (PET) is most useful for detecting and characterizing distant metastases. Both MDCT and PET are useful for assessment of treatment response following preoperative chemotherapy and for detection of recurrence after surgical resection. This review article discusses the usefulness of imaging modalities for detecting, staging and assessing treatment response for GC and the potential role of newer applications including CT volumetry, virtual gastroscopy and perfusion CT in the management of GC.

Differential diagnosis between benign and malignant ulcers: 320-row CT virtual gastroscopy

PURPOSE

This study aims to assess the diagnostic accuracy of virtual gastroscopy obtained by 320-row computed tomography (CT) examination in differentiating benign from malignant gastric ulcers (GUs).

MATERIALS AND METHODS

49 patients (30 M, 19 F, mean age 58.6) with endoscopic and histological diagnosis of GU underwent CT examination. A hypotonizing drug was administered and gastric walls were distended by air in order to perform virtual endoscopy. Based on morphological features, GUs were subdivided into benign or malignant forms by two blinded radiologists. Interobserver agreement was evaluated using Cohen’s kappa (κ) test. CT results were then compared with endoscopic and histological findings, having the latter as the reference standard.

RESULTS

Thirty-five out of 49 patients (71%) were affected by malignant ulcers, while in the remaining 14 cases diagnosis of benign GU was made. Virtual gastroscopy showed diagnostic accuracy, sensitivity, and specificity values of 94%, 91%, and 100%, respectively, in differentiating benign from malignant ulcers. Almost perfect agreement between the two readers was found (κ = 0.86).

CONCLUSION

CT virtual gastroscopy improves the identification of GUs and allows differentiating benign from malignant forms.

Staging Laparoscopy in Carcinoma of Stomach: A Comparison with CECT Staging

Background. aim of this study was to compare the role of diagnostic laparoscopy and contrast enhanced computed tomography (CECT) of abdomen in the staging of stomach carcinoma. Methods. This was a prospective study conducted in a tertiary care hospital over a period of two years and included 50 patients of endoscopy and biopsy proven stomach carcinoma that were found to be operable on CECT. Diagnostic laparoscopy was performed in all patients before proceeding to a formal laparotomy. Results. Metastasis was detected at diagnostic laparoscopy in 14 (28%) patients. CECT correctly identified the T stage in 22 (61%) patients. Overall accuracy of CECT for T staging was 74% with a a sensitivity of 65% and a specificity of 79%. Laparoscopy correctly identified the T stage in 26 (72%) patients. Overall accuracy of laparoscopy for T staging was 81% with a sensitivity of 76% and specificity of 86%. the most common N stage on CECT was N0 (50%). CECT correctly identified the N stage in 26 (72%) patients. Overall accuracy of CECT for N staging was 86% with a sensitivity of 50% and a specificity of 90%. the most common N stage on laparoscopy was N0 and N2 (42% each). Laparoscopy correctly identified the N stage in 27 (75%) patients. Overall accuracy of Laparoscopy for N staging was 88% with a sensitivity of 53% and specificity of 91%. Conclusion. Laparoscopy is a valuable technique in staging of stomach carcinoma and has an important role in the detection of intra-abdominal metastasis missed by CECT.

Effectiveness of endoscopic clipping and computed tomography gastroscopy for the preoperative localization of gastric cancer

Purpose

Before laparoscopic gastrectomy for gastric cancer can be planned, it is very important to know the precise location of the tumor. The aim of this study was to evaluate 3 methods of predicting the exact location of the tumor: preoperative gastrofibroscopy (GFS), preoperative computed tomography gastroscopy (CT), and intraoperative gastroscopy-guided laparoscopy (Lap).

Methods

In this study, 15 patients were prospectively identified, and endoscopic clips were preoperatively placed on the proximal 1 cm of the tumor, at the angle on the greater curvature and opposite the angle on the greater curvature. The distances between the pylorus and the proximal tumor clip (PT), the angle clip (PA), the greater curvature clip (PG), and the gastroesophageal junction were measured by preoperative GFS, preoperative CT, intraoperative Lap, and visual inspection (Vis).

Results

PT, PA, and PG values measured by preoperative GFS differed significantly from the Vis values (P < 0.01). However, preoperative CT measurements of PT, PA, and PG did not differ from the Vis values (P = 0.78, P = 0.48, and P = 0.53, respectively). Intraoperative Lap and Vis PT values differed by only 1.1 cm on an average (P = 0.10), but PA and PG values varied by 1.9 and 3.4 cm, respectively (P = 0.01 for both).

Conclusion

Endoscopic clipping combined with preoperative CT gastroscopy is more useful than preoperative GFS for preoperatively predicting the location of early gastric cancers and will be helpful for planning laparoscopic gastrectomy.

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.

Evaluation of early gastric cancer at multidetector CT with multiplanar reformation and virtual endoscopy

Early gastric cancer (EGC) is defined as a carcinoma in which invasion is limited to the mucosa and submucosa, regardless of lymph node status and distant metastasis. Recent advances in multidetector computed tomography (CT) with multiplanar reformation (MPR) provide a powerful tool for identifying gastric wall invasion and the perigastric extent of gastric cancer. In addition, MPR images confer advantages in the assessment of both intra- and extraluminal processes of the gastric wall and the evaluation of more distant regions, such as the paraaortic lymph nodes and other abdominal organs. Virtual endoscopy performed after air distention of the stomach can aid in the evaluation of gastric endoluminal morphologic features and the extent of EGC. Moreover, virtual endoscopy helps in detecting subtle mucosal changes and differentiating them from submucosal lesions in the same way as conventional endoscopy. Virtual endoscopy can depict abnormal endoluminal lesions within a wider field of view than can conventional endoscopy, and there are no "blind spots" because retrospective image reformation is available, which provides useful information for preoperative mapping. Multidetector CT with MPR and virtual endoscopy is a powerful, noninvasive tool for the early detection and accurate preoperative staging of EGC.

Three-dimensional MDCT for preoperative local staging of gastric cancer using gas and water distention methods: a retrospective cohort study

OBJECTIVE

The purpose of this article is to compare the T-staging accuracy and lesion detectability of MDCT with gas distention versus water distention according to the surgical and histopathologic findings, for the preoperative evaluation of gastric cancer.

MATERIALS AND METHODS

For a 3-month period, 113 consecutive patients (72 men and 41 women; age range, 23-85 years; mean age, 58 years) with 116 surgically confirmed gastric cancers from a single institution were included in our study. All patients had undergone preoperative MDCT with either effervescent granules taken orally (n = 55) or after having drunk 1,000 mL of tap water (n = 58) to create gastric distention. In addition to transverse images, multiplanar reformation images and 3D surface shaded display images were also obtained with gas distention CT, and multiplanar reformation images were obtained with water distention CT. The CT images were retrospectively reviewed by two abdominal radiologists separately with regard to T staging and lesion detectability. The accuracy values were compared between the two methods using Fisher's exact test.

RESULTS

The T-staging accuracy for gastric cancer did not differ significantly between gas distention and water distention CT scans, according to both radiologists (p > 0.05). Furthermore, the staging accuracy values for T1a cancers on gas distention CT scans for radiologists 1 and 2 were also comparable with those of water distention CT scans (91.1% vs 85% for radiologist 1 and 89.3% vs 85% for radiologist 2; p > 0.05). However, the tumor detection rate was significantly higher on gas distention CT scans using 2D and surface shaded display images for both radiologists (94.6% for radiologist 1 and 91.1% for radiologist 2), compared with the rates for water distention CT scans (78.3% and 73.3%) or gas distention CT scans using only 2D images (75.0% and 67.9%) (p < 0.05).

CONCLUSION

MDCT using the gas distention technique showed performance comparable to that of the water distention technique for the T staging of preoperative gastric cancer with better lesion detectability.

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.

Impact of EUS-guided FNA on management of gastric carcinoma

BACKGROUND

EUS is an integral part of the pretherapeutic evaluation program for patients with upper GI cancer.

OBJECTIVE

To evaluate the impact of EUS-guided FNA on the clinical management of patients with gastric cancer.

DESIGN

The study included patients with confirmed gastric carcinoma who were referred to the Department of Surgical Gastroenterology, Gentofte Hospital, Copenhagen University, Copenhagen, Denmark, during a 6-year period (2001-2007).

SETTING

The patients underwent standard pretherapeutic evaluation. If no signs of incurability were detected, the patients were offered EUS and EUS-guided FNA. EUS-guided FNA was performed when lymph nodes or lesions were considered to be distant metastases. A board of surgeons was asked to evaluate the management of the patients after the results obtained by EUS-guided FNA were revealed.

PATIENTS

This study involved 234 patients with gastric carcinoma.

INTERVENTION

EUS-guided FNA.

MAIN OUTCOME MEASUREMENTS

Number of patients with distant metastasis diagnosed by EUS-guided FNA, with the avoidance of unnecessary surgery.

RESULTS

A total of 81 consecutive patients underwent EUS-guided FNA. Ninety-nine lesions were targeted, and 61 (62%) of these lesions were found to be malignant. In 38 of 81 patients (42%) distant metastases were confirmed by EUS-guided FNA. As judged by the board of surgeons, EUS-guided FNA changed the management plan in 34 of 234 patients (15%).

LIMITATION

The positive EUS-guided FNA diagnoses were not surgically verified.

CONCLUSION

EUS-guided FNA is a very important modality and should be integrated as a routine procedure in the preoperative staging algorithm of gastric cancer.

Determining gastric cancer resectability by dynamic MDCT

PURPOSE

Multi-detector row CT (MDCT) has been widely used to detect primary lesions and to evaluate TNM staging. In this study we evaluated the accuracy of dynamic MDCT in the preoperative determination of the resectability of gastric cancer.

METHODS

MDCT was used to image 350 cases of gastric cancer diagnosed by biopsy before surgery. MDCT findings regarding TNM staging and resectability were correlated with surgical and pathological findings.

RESULTS

The accuracy of MDCT for staging gastric cancer was high, especially for tumour stage T1 (94.3%), lymph node stage N2 (87.3%), and for predicting distant metastases (>96.6%). When resectability was considered to be the outcome, the total accuracy of MDCT was 87.4%, sensitivity was 89.7% and specificity was 76.7%. Results showed high sensitivity for identifying peritoneal seeding (90.0%) and for predicting liver metastasis (80.0%).

CONCLUSION

Dynamic enhanced MDCT is useful for TNM staging of gastric cancers and for predicting tumour respectability preoperatively.

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.

Helical CT evaluation of the preoperative staging of gastric cancer in the remnant stomach

OBJECTIVE

The objective of our study was to evaluate the diagnostic performance of helical CT for evaluating the preoperative staging of gastric cancer in the remnant stomach.

MATERIALS AND METHODS

Preoperative helical CT images of 67 patients with gastric cancer in the remnant stomach were independently analyzed regarding staging of the tumor by two radiologists who were blinded to histopathologic and surgical results. The differences in their assessments were resolved by consensus including the opinion of a third radiologist. The radiologists were asked to determine the depth of tumor invasion of the gastric wall (T stage), classifying it as </= T2, T3, or T4; local lymph node involvement (N stage); and solid organ metastasis or peritoneal involvement (M stage). TNM staging on CT was correlated with the histopathologic results of the resected specimen or with the surgical findings. Interobserver agreement was assessed using weighted kappa statistics.

RESULTS

The overall accuracy of T staging for reviewers 1 and 2 and for the consensus reading were 83.6%, 78.2%, and 85.4%, respectively. Five of 34 </= T2 lesions were misdiagnosed as T3. The cause of the overstaging was the misconception of the postoperative fibrotic change of the anastomotic site as perigastric tumoral infiltration. Three of 18 T4 lesions were understaged because of inadequate gastric distention (n = 1) and misinterpretation of adjacent organ involvement as partial volume averaging (n = 2). The accuracy of N staging and M staging were 81.8% and 94.0% for reviewer 1; 78.2% and 91.0% for reviewer 2; and 81.8% and 94.0% for the consensus reading, respectively. The weighted kappa values of T staging, N staging, and M staging were 0.676, 0.619, and 0.924, respectively.

CONCLUSION

Contrast-enhanced helical CT can be used successfully to preoperatively evaluate the staging of remnant stomach cancer in patients who have undergone previous gastric resection.

Gastric cancer staging at isotropic MDCT including coronal and sagittal MPR images: endoscopically diagnosed early vs. advanced gastric cancer

BACKGROUND

The aims of this study are to evaluate and compare the accuracies of isotropic multi-detector row CT (MDCT) including multiplanar reconstruction (MPR) images for preoperative staging of endoscopically diagnosed early gastric cancer (eEGC) and advanced gastric cancer (eAGC).

METHODS

One hundred and five patients with endoscopically proven gastric cancer underwent isotropic MDCT. Three independent radiologists evaluated T and N staging both on transverse images only and on three orthogonal MPR images. The staging of each tumor was surgico-pathologically confirmed. The receiver operating characteristic (ROC) analysis and the Wilcoxon signed ranked test were used for statistical analyses.

RESULTS

In 30 eAGCs, the accuracies for T and N staging with MPR imaging were better than those with transverse imaging (each P < 0.05). In 34 eEGCs, however, only the accuracy of T2 or higher with MPR imaging was higher than that with transverse imaging (P < 0.05).

CONCLUSIONS

Isotropic MDCT with MPR images including coronal or sagittal reconstructions can improve the accuracies of preoperative T and N staging of eAGC, while having little impact on the accuracy for eEGC.

Palliative management of gastric cancer

Advanced gastric cancer and its palliative treatment have a long and interesting history. Today, gastric adenocarcinoma is the second leading cause of cancer death worldwide. Unfortunately, many cases are not diagnosed until late stages of disease, which underscores the importance of the palliative treatment of gastric cancer. Palliative care is best defined as the active total care of patients whose disease is not responsive to curative treatment. Although endoscopy is the most useful method for securing the diagnosis of gastric adenocarcinoma, computed tomography may be useful to assess local and distant disease. The main indication for the institution of palliative care is the presence of advanced gastric cancer for which curative treatment is deemed inappropriate. The primary goal of palliative therapy of gastric cancer patients is to improve quality, not necessarily length, of life. Four main modalities of palliative therapy for advanced gastric cancer are discussed: resection, bypass, stenting, and chemotherapy. The choice of modality depends on a variety of factors, including individual patient prognosis and goals, and should be made on case-by-case basis. Future directions include the discovery and development of serum or stool tumor markers aimed at prevention, improving prognostication and stratification, and increasing awareness and education.

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

OBJECTIVE

The objective of our study was to assess the diagnostic performance of virtual gastroscopy using MDCT for the detection of early gastric cancer (EGC) compared with 2D axial CT, focusing on interobserver reliability.

MATERIALS AND METHODS

During an 11-month period, we performed CT examinations of 94 consecutive patients with EGC and a control group composed of 68 patients without EGC. Three radiologists retrospectively interpreted the 2D axial CT and virtual gastroscopy images. Diagnostic performances were compared within each observer using the area under the receiver operating characteristic curve (A(z)). Sensitivity and specificity were also calculated for each individual observer. The simple kappa statistic was used to evaluate interobserver reliability in the detection of EGC.

RESULTS

The diagnostic performance for overall lesion detection in patients with EGC was significantly higher with virtual gastroscopy (A(z) = 0.829-0.885) than with 2D axial CT (A(z) = 0.734-0.793) (p < 0.001). The sensitivity and specificity of virtual gastroscopy for EGC were 78.7-84.0% and 83.8-91.2%, respectively. The sensitivity and specificity of 2D axial CT for EGC were 62.8-69.2% and 83.8-92.7%, respectively. Virtual gastroscopy showed a higher sensitivity for EGC than 2D axial CT (p < 0.001). The interobserver reliabilities showed moderate to substantial agreement (kappa = 0.40-0.74 for 2D axial CT, kappa = 0.57-0.71 for virtual gastroscopy).

CONCLUSION

Virtual gastroscopy showed excellent results with a good interobserver reliability for the detection of EGC compared with 2D axial CT.

Three-dimensional MDCT Gastrography Compared With Axial CT for the Detection of Early Gastric Cancer

OBJECTIVE

To assess the diagnostic performance of multidetector-row computed tomography (CT) 3-dimensional CT gastrography (3-D CTG) to detect early gastric cancer (EGC) compared with axial CT images alone.

METHODS

Contrast-enhanced multidetector-row CT scanning was performed on 39 patients with histopathologically proven EGC. By using volume-rendering technique, CTG images were created and interval reviews of both the axial images without and with 3-D CTG images were performed independently by 2 radiologists retrospectively. The stomach was divided into 4 segments (ie, the cardia or fundus, body, angle, and antrum). For 156 gastric segments, the radiologists determined the presence of the lesion using a 5-point confidence level. The radiologists' performance for the lesion detection was evaluated by means of receiver operating characteristic analysis. Interobserver agreement was also analyzed. The ability of CTG to reveal the extent and the morphological features of the lesions was also evaluated and compared with the results of conventional studies.

RESULTS

Histopathologically, 41 EGCs were identified in 39 patients: 1 lesion was located in the fundus, 16 in the body, 9 in the angle, and 15 in the antrum. When 3-D CTG images were used, the receiver operating characteristic curve (AZ) analysis revealed a significant improvement in the diagnostic performance of both reviewers (AZ using axial CT images only, 0.608 and 0.602 for reviewers 1 and 2, respectively; AZ using CTG images, 0.821 and 0.822 for reviewers 1 and 2, respectively) (P < 0.05). The 3-D CTG also improved the sensitivity from 27% to 73% for reviewer 1 and from 29% to 76% for reviewer 2 (P < 0.05), as compared with the sensitivity when using axial CT images only. In addition, almost perfect agreement was achieved for CTG (weighted kappa, 0.836), whereas there was only moderate agreement for the axial CT images (weighted kappa, 0.445). The CTG provided information similar to that obtained by barium study and endoscopy in 51.6% and 59.5%, respectively, of the cases.

CONCLUSIONS

The combined interpretation of axial and 3-D CTG was significantly better for detecting EGC, with a diagnostic confidence higher than that using axial CT imaging alone.

Imaging in local staging of gastric cancer: a systematic review

PURPOSE

Endoscopic ultrasound (EUS) has been established as the diagnostic modality of choice in local (T) staging of gastric cancer. Multidetector row computed tomography (MDCT) and magnetic resonance imaging (MRI) are promising alternatives. The aim of this study was to systematically review the literature regarding the performance of each of these imaging modalities.

METHODS

A systematic search for relevant studies was performed in the PubMed/MEDLINE and EMBASE databases. Two reviewers independently assessed the methodological quality of each study. Local staging performance of included studies was calculated.

RESULTS

Twenty-two EUS studies, five MDCT studies, one combined EUS and MDCT study, and three MRI studies met the inclusion criteria. The studies were of moderate methodological quality. Diagnostic accuracy of overall T staging for EUS, MDCT, and MRI varied between 65% to 92.1%, 77.1% to 88.9%, and 71.4% to 82.6%, respectively. Sensitivity for assessing serosal involvement for EUS, MDCT, and MRI varied between 77.8% to 100%, 82.8% to 100%, and 89.5% to 93.1%, respectively. Specificity for assessing serosal involvement for EUS, MDCT, and MRI varied between 67.9% to 100%, 80% to 96.8%, and 91.4% to 100%, respectively.

CONCLUSION

EUS, MDCT, and MRI achieve similar results in terms of diagnostic accuracy in T staging and in assessing serosal involvement. Most experience has been gained with EUS. Few MDCT studies and even fewer MRI studies are available. Thus, EUS remains the first-choice imaging modality in preoperative T staging of gastric cancer.

Preoperative Staging and Postoperative Surveillance for Gastric Cancer

Physicians must consider multiple factors when determining the most appropriate preoperative imaging strategy for gastric cancer. Health care resources are not unlimited, and the use of multiple expensive imaging techniques that do not alter treatment decisions is not recommended. With this in mind, EGD and CT scan alone should form the basis for preoperative evaluation, with further imaging considered only in selected cases. Based on the reviewed literature, we do not recommend routine surveillance imaging after curative surgery for gastric cancer. We agree with current NCCN guidelines that recommend history and physical examination every 4 to 6 months for 3 years, followed by yearly examinations. Imaging studies and endoscopy should be selectively performed in symptomatic patients.

64 multidetector-row computed tomography for preoperative evaluation of gastric cancer: histological correlation

OBJECTIVE

To assess the accuracy of 64 multidetector-row computed tomography (MDCT) in the diagnosis and staging of gastric cancer.

METHODS

This study was approved by the institutional review board, and the patients involved gave informed consent. Forty-four patients (34 men and 10 women; mean age, 57 years) with gastric carcinoma underwent preoperative 64 MDCT (SOMATOM Sensation 64; Siemens Medical System, Forchheim, Germany; slice collimation, 0.6 mm; slice width, 5 mm; feed/rotation, 23 mm; pitch factor, 1.2; kernel, B30f; and gantry speed, 0.5 second per rotation). Gastric distension was achieved by ingestion of 8 g of effervescent granules. Scanning was performed during arterial and portal phases, as determined with bolus tracking and automated triggering technique after intravenous administration of 100 mL of contrast materials (4 mL/s). All computed tomography scans were retrospectively reviewed by 2 radiologists. Each tumor was staged according to the TNM classification system. All patients underwent surgery. Computed tomography results were compared with histological staging of tumor invasion depth and regional lymph node metastasis.

RESULTS

The accuracy of 64 MDCT for detection of gastric cancer was 90% (18/20) and 100% (24/24) in early and advanced gastric cancer, respectively, with an overall detection rate of 95% (42/44). Its accuracy for determination of tumor penetration depth was 89% (16/18) and 88% (21/24) in early and advanced gastric cancer, respectively, with an overall accuracy of 88% (37/42). Its accuracy for determination of lymph node metastasis was 90% (18/20) and 71% (17/24) in early and advanced gastric cancer, respectively, with an overall accuracy of 80% (35/44).

CONCLUSIONS

The 64 MDCT is a promising technique for the detection and preoperative staging of gastric cancer.

Gastric cancer: preoperative local staging with 3D multi-detector row CT--correlation with surgical and histopathologic results

PURPOSE

To prospectively evaluate accuracy of multi-detector row computed tomographic (CT) images for preoperative staging of gastric cancer by using surgical and histopathologic results as reference standards.

MATERIALS AND METHODS

This study had institutional review board approval; informed consent was obtained from all patients. Multi-detector row CT included acquisition of virtual gastroscopy images after air distention and contrast material-enhanced dynamic transverse and multiplanar reformation (MPR) images after water distention. Fifty-five consecutive patients with gastric cancer (38 men, 17 women; age range, 37-84 years; mean age, 63 years) underwent preoperative CT. All received 6 g of gas-producing crystals before unenhanced CT scanning for gastric distention and virtual gastroscopy. Patients drank 800-1000 mL of tap water to establish a background for dynamic contrast-enhanced CT scans. Images were obtained in late arterial, portal venous, and delayed phases with start delays of 40, 70, and 150 seconds, respectively. All patients underwent surgery. CT findings were compared with surgical and histopathologic results. Differences in accuracy of transverse and MPR images for T and N staging were assessed with the McNemar exact test. Statistical significance was inferred at P < .05.

RESULTS

Detection rates of primary tumors with transverse images, MPRs, and combinations of MPR and virtual gastroscopy images were 91% (50 of 55), 96% (53 of 55), and 98% (54 of 55), respectively. Overall accuracy in assessment of tumor invasion of the gastric wall (T stage) was significantly better with MPR images (89% [49 of 55]) than with transverse images (73% [40 of 55]) (P < .01). Overall accuracy for lymph node (N) staging was 78% (43 of 55) with MPR images and 71% (39 of 55) with transverse images. This difference was not significant (P = .103).

CONCLUSION

Multi-detector row CT with combined water and air distention can improve the accuracy of preoperative staging of gastric cancer. MPRs yield significantly better overall accuracy than transverse images for tumor staging but not for lymph node staging.

Utility of multidetector CT in the diagnosis of gastric bare area invasion by proximal gastric carcinoma

PURPOSE

To investigate the utility of multidetector CT (MDCT) in the diagnosis of gastric bare area (GBA) invasion by proximal gastric carcinoma (PGC).

METHODS

Sixty-eight consecutive patients with biopsy-proven PGC underwent MDCT scan prior to gastrectomy. We evaluated the CT images separately for the site, size, depth, lymph node, and enhancement characteristic of each case. Each postsurgical stomach specimen was axially sectioned and comparison was made to determine the correlation between the CT findings and the pathological examination of each tumor bearing slice.

RESULTS

The sensitivity for detecting GBA involvement in patients with PGC was 84%. MDCT correctly identified 32 of 38 patients with GBA invasion and 10/13 (77%) tumors with metastatic lymph node greater than 5 mm in GBA or subphrenic retroperitoneal space. 33/36 (92%) patients with tumor extension within the edge of the gastric wall and 28/32 (88%) patients with tumor infiltration into subphrenic fat were correctly identified. MDCT correctly predicted the infiltration of tumor into the diaphragm in all 14 patients and identified 6/11 (55%) patients with gastrophrenic ligament invasion.

CONCLUSION

MDCT may be of value in assessing the important radiological characteristics of GBA invasion in patients with PGC.

Diagnostic accuracy of multidetector row computed tomography in T- and N staging of gastric cancer with histopathologic correlation

PURPOSE

To evaluate the diagnostic accuracy of multidetector row computed tomography (MDCT) for the preoperative T- and N staging of gastric cancer.

MATERIALS AND METHODS

Eighty-four consecutive patients with gastric cancer underwent preoperative MDCT. Except for 15 patients who did not undergo surgery, 69 patients were included in our study. Two radiologists independently evaluated the T- and N staging on the axial CT images alone and in combination with the MPR images. For N staging, the new TNM and Japanese classifications were independently used. Differences in staging accuracy for T- and N staging were assessed using the McNemar test.

RESULTS

The overall T staging accuracy of the axial and combined axial and MPR images was as follows: 67% (47 of 70 cancers) versus 77% (54 of 70 cancers) (P=0.039). The overall N staging accuracy of the axial and combined axial and MPR images was as follows: 59% (41 of 69 cancers) versus 67% (46 of 69 cancers) (P=0.180, Japanese classification) and 54% (37 of 69 cancers) versus 59% (41 of 69 cancers) (P=0.109, TNM classification).

CONCLUSIONS

Using MPR images enables more accurate preoperative T staging of gastric cancer, but not for N staging in either classification system.

Present state of the Mini-Invasive Surgery (MIS) in esophageal and gastric cancer

The purpose of this review is to stress the role of the Mini-Invasive Surgery (MIS) in the treatment of the esophagogastric malignant illnesses, supporting ourselves on the most relevant publications of the literature as well as on our own experience in this subject. In short, although no randomised prospective study has proven the MIS advantages in relation to the traditional surgery in the esophagectomy due to cancer, some authors preferently indicate this approach to selected and informed enough patients, who present the following: - High grade dysplasia, preferently choosing from laparoscopic transhiatal esophagectomy (LTE). - Carcinoma in situ, preferently choosing the LTE vs thoracoscopy. - Esophageal tumour locally advanced, in resectable patients with contraindication for a thoracotomy or, in initially non-resectable patients with tumoral reduction after neo-adjuvant chemo-radiotherapy. The arguments given by the authors are the postoperative spectacular improvement in relation to the comfort and quality of life and, the absence of oncological negative effects in the long-term followup. Concerning gastric cancer, the MIS, as exeresis surgical tool in the so-called <<advanced>> gastric forms, is such a definite and oncological approach as the traditional approach, and superior to this as far as quality of life is concerned. When the MIS is used for treating locally advanced forms of gastric cancer, it is as safe as the laparotomic way and it seems to obtain the same oncological outcomes in the long-term.

CT gastrography

The rapid dissemination of multidetector-row computed tomographic (CT) technology will make faster and more accurate gastric imagining available. Two-dimensional multiplanar reconstruction and CT gastrography including virtual gastroscopy and transparency rendering using volume rendering are types of interactive two- and three-dimensional medical imaging tools. It provides multiplanar cross-sectional imaging, gastroscopic viewing, and upper gastrointestinal series imaging in the same data acquisition. Two-dimensional multiplanar reconstruction provides accurate staging of gastric cancer and extraluminal information such as lymphadenopathy and distant metastasis. Virtual gastroscopy detects subtle mucosal changes and differentiates them from submucosal lesions in the same way as gastroscopy. Transparency rendering provides global orientation of the focal findings in the stomach in the same way as upper gastrointestinal series findings and provides useful information for preoperative mapping. Thus, CT gastrography is a promising method for evaluating gastric lesion despite its limitations.

Early gastric cancer: virtual gastroscopy

Gastric cancer is one of the most common cancers and one of the most frequent causes of cancer-related deaths worldwide. Early detection and accurate preoperative staging of early gastric cancer (ECG) offers the best prognosis and is essential for planning optimal therapy such as endoscopic mucosal resection or gastric resection. Recent advances in computed tomographic technology and three-dimensional imaging software have enabled more accurate gastric imaging. Virtual gastroscopy (VG) is helpful in the detection and evaluation of EGC in the same way as gastroscopy. VG has a wider field of view than conventional gastroscopy, the angle of the virtual cancer can be adjusted omnidirectionally, and it has no blind point because retrospective reconstruction is available. Thus, VG is a promising method for evaluating gastric lesions despite its limitations. This report describes the clinical usefulness of VG with multidetector row computed tomography for EGC and axial computed tomography.

Gastric cancer by multidetector row CT: preoperative staging

The role of computed tomography (CT) in the preoperative staging of gastric cancer, even if controversial, may be fundamental for evaluating the local extent and nodal involvement of the disease, especially in locally advanced cases. However, previous results of CT staging have not been satisfactory for predicting the invasive depth of the tumor or possible nodal metastases. Recently introduced multidetector row CT (MDCT) and three-dimensional (3D) imaging are expected to overcome the limitations in cancer staging by offering rapid and accurate information for space perception, detailed hemodynamics, and real-time 3D processing of volumetric data sets. In particular, virtual endoscopic imaging may be helpful for detecting early gastric cancer. In our experience, T and N stagings of gastric cancer were improved with 3D MDCT when using volume rendering and virtual endoscopic imaging compared with conventional axial two-dimensional (2D) CT (accuracy of T staging with 3D vs. 2D CT images, 84% vs. 77%; accuracy of N staging, 63% vs. 61% with 3D vs. 2D images, respectively). In particular, the detection rate of early gastric cancer was markedly increased up to 96% when using 3D MDCT. Therefore, we believe that 3D MDCT of the stomach may enhance the performance of CT in the preoperative evaluation of patients who have gastric cancer by offering easy early detection of lesions and accurate tumor staging through the 3D imaging process.

T staging of gastric cancer: role of multi-detector row CT

PURPOSE

To evaluate retrospectively the accuracy of multi-detector row computed tomography (CT) in the assessment of serosal invasion in patients with gastric cancer.

MATERIALS AND METHODS

The Ethics Committee does not require approval or informed consent for retrospective studies. Forty-one consecutive patients (24 men, 17 women; mean age, 68 years) with gastric cancer were included in this study. All patients were given 600 mL of tap water to drink and were positioned prone or supine on the scanning table. The detector row configuration included four detector rows, a section thickness of 1.25 mm, a pitch of 6, and a reconstruction interval of 0.63 mm. Transverse and multiplanar reconstruction images were simultaneously evaluated by two independent observers to assess the depth of tumor invasion in the gastric wall (ie, T stage). T staging at multi-detector row CT was compared with T staging at histologic evaluation (reference standard), which was performed by means of surgical or histologic examination of the resected specimen. We also calculated the sensitivity, specificity, and accuracy of multi-detector row CT for each observer in the assessment of serosal invasion.

RESULTS

Analysis of interobserver agreement showed substantial or almost perfect agreement (nonweighted kappa value of 0.78 and weighted kappa value of 0.85). Correct assessment of gastric wall invasion was 80% and 85% for observers 1 and 2, respectively. The sensitivity, specificity, and accuracy of multi-detector row CT in the assessment of serosal invasion were 90%, 95%, and 93%, respectively, for observer 1 and 80%, 97%, and 93%, respectively, for observer 2. Overstaging occurred in six patients, and understaging occurred in five patients. All understaged tumors were scirrhous subtype gastric cancer.

CONCLUSION

Multi-detector row CT scanning of patients with gastric cancer gave 93% accuracy in the assessment of serosal invasion in patients with gastric cancer.

Evaluation of contrast-enhanced helical hydro-CT in staging gastric cancer

AIM: To discuss the helical computed tomography (CT) characteristics of gastric cancer and evaluate the diagnostic value of contrast-enhanced helical hydro-CT (HHCT) in staging gastric cancer.

METHODS: A total of 50 patients with gastric cancer were included in this study. The CT findings in them were retros-pectively analyzed and correlated with pathologic findings at surgery. All patients were preoperatively imaged by plain and contrast-enhanced helical CT after orally ingesting 1 000-1 500 mL water. Peristalsis was minimized by intra-venous administration of spasmolytics.

RESULTS: The foci of gastric cancer became more prominent in all the 50 patients and showed strong enhancement in contrast-enhanced HHCT. The tumor was located at the gastric cardia in 14 cases, at the gastric fundus in 3 cases, at the gastric body in 8 cases, at the gastric antrum in 4 cases, at the gastric fundus and the body in 8 cases, at the gastric body and antrum in 11 cases, and at three segments of the stomach in 2 cases. The CT features of gastric cancer were focal or diffuse mural thickening, soft tissue mass, cancerous ulcer, stenosis of stomach, infiltration to adjacent tissues, lymph node and distant metastases. Strong contrast enhancement of the gastric wall was closely related to gastric cancer. The accuracy rate of contrast-enhanced HHCT in staging gastric cancer was 86% (43/50). The detection rate of lymph node metastases by CT was 60% (12/20).

CONCLUSION: Contrast-enhanced HHCT is a reliable method to diagnose and stage gastric cancer.

Gastric cancer staging at multi-detector row CT gastrography: comparison of transverse and volumetric CT scanning

PURPOSE

To prospectively evaluate the accuracy of multi-detector row computed tomography (CT) gastrography for preoperative staging of gastric cancer, with pathologic and surgical results as the reference standard.

MATERIALS AND METHODS

This study was approved by the institutional review board, and patients gave written informed consent. One hundred six patients (72 male, 34 female; mean age, 56 years) with endoscopically proved gastric cancer underwent unenhanced and contrast material-enhanced multi-detector row CT gastrography, with effervescent granules used as oral contrast material. Two experienced radiologists independently evaluated the depth of tumor invasion into the gastric wall (tumor staging), the involvement of regional lymph nodes (nodal staging), and the presence or absence of metastasis (metastatic staging) on transverse and volumetric CT images, which included images produced with multiplanar reformation and a virtual endoscopic technique. TNM staging of each tumor was compared with the pathologic and surgical results. Diagnostic accuracy in TNM staging was analyzed.

RESULTS

Gastric cancer was detected in 92 (87%) of 106 study patients with transverse CT imaging and in 104 (98%) with volumetric CT imaging. The overall accuracy of the tumor staging was 77% with transverse CT imaging and 84% with volumetric CT imaging (P < .001). The overall accuracy for lymph node staging was 62% with transverse CT imaging and 64% with volumetric CT imaging (P = .057). For staging of metastases, there was no difference between transverse and volumetric CT imaging (86% for both) (P > .99).

CONCLUSION

Multi-detector row CT gastrography with multiplanar reformation and virtual endoscopy, compared with transverse CT imaging, can improve the accuracy of preoperative staging of gastric cancer. This difference was significant for tumor staging but not for the staging of lymph nodes and metastases.

Usefulness of three-dimensional, multidetector row CT (virtual gastroscopy and multiplanar reconstruction) in the evaluation of gastric cancer: a comparison with conventional endoscopy, EUS, and histopathology

BACKGROUND

The aim of this study was to assess the role of three-dimensional multidetector row CT for detection, precise localization, and staging of gastric cancer by comparison with conventional endoscopy, EUS, and histopathology.

METHODS

Sixty-three patients with gastric cancer (31 early stage, 32 advanced) were evaluated by EGD with biopsies, EUS, and three-dimensional multidetector row CT between January 2003 to August 2003. Three-dimensional multidetector row CT findings were analyzed by a single radiologist blinded to the endoscopic findings. Among 63 patients, the findings were confirmed in 48 at surgery or by EMR. In the remaining cases, the findings were confirmed by EGD and biopsy specimen. The accuracy of three-dimensional multidetector row CT for detection, localization, and staging of gastric cancer was determined, compared with endoscopy, EUS, and histopathology.

RESULTS

Among the 63 patients, there were 67 gastric cancers. The overall accuracy of three-dimensional multidetector row CT for detection of gastric lesions was 94% (63/67), with accuracies of 96.7% (30/31) and 100% (32/32) for detection of, respectively, early and advanced stage gastric cancer. The overall accuracy, sensitivity, and specificity for EUS and three-dimensional multidetector row CT in the pre-operative determination of depth of invasion (T stage) were, respectively, 87.5%, 82.4%, and 96%; and 83.3%, 69.1%, and 94.4%. The accuracy, sensitivity, and specificity of EUS and three-dimensional multidetector row CT for lymph node staging was, respectively, 79.1%, 57%, and 89.5%; and 75%, 57.4%, and 89.3%.

CONCLUSIONS

Three-dimensional multidetector row CT, along with virtual gastroscopy is a promising method for pre-operative evaluation of gastric cancer.

Preoperative staging of gastric adenocarcinoma: comparison of helical CT and endoscopic US

PURPOSE

To compare the performance of helical computed tomography (CT) and endoscopic ultrasonography (US) in the preoperative staging of gastric cancer.

MATERIALS AND METHODS

Fifty-one consecutive patients with a primary malignant gastric tumor (stage T2-T4) were preoperatively evaluated with both helical CT and endoscopic US within 3 days. Each tumor was staged according to the TNM classification system with both modalities. All patients subsequently underwent surgery. Results of CT and endoscopic US were compared with histologic staging of tumor invasion depth and regional lymph node metastasis. For comparison of CT and endoscopic US data, the marginal homogeneity test was used, and a P value of less than.05 was determined to indicate statistical significance.

RESULTS

In comparison with histologic results, CT achieved correct T staging in 39 patients (76%) and correct N staging in 35 patients (70%). The corresponding results for endoscopic US achieved correct T staging in 44 patients (86%) and correct N staging in 45 patients (90%). There was no significant difference between T staging (P =.55) and N staging (P >.99). Because of challenging detection of wall layers, correct T staging was difficult for CT and endoscopic US in the differentiation of T2 and T3 lesions.

CONCLUSION

Compared with endoscopic US, helical CT focused on the stomach provides valuable results regarding T and N staging in patients with gastric cancer.

Preoperative simulation of vascular anatomy by three-dimensional computed tomography imaging in laparoscopic gastric cancer surgery

BACKGROUND

Treatment of early gastric cancer may be an ideal application for laparoscopic surgery. But laparoscopic surgery has various limitations derived from the lack of tactile feedback and a two-dimensional display of the operative field. So, laparoscopic surgery is technically challenging and requires a more detailed understanding of local anatomy than conventional open surgery does. The purpose of this study was to evaluate the value of three-dimensional computed tomography imaging in the preoperative simulation of laparoscopic gastric cancer surgery.

STUDY DESIGN

Multidetector-row helical CT was performed preoperatively in 49 patients who underwent laparoscopic gastric cancer surgery. Scanning was initiated approximately 20 seconds after an intravenous injection of 100 mL of contrast material at 5 mL/second. Three-dimensional CT images were reconstructed using the volume-rendering technique.

RESULTS

3D-CT imaging depicted the stomach, arterial, and venous anatomy and was able to identify important vascular variants. Preoperative information concerning the right gastric artery led us to the site of its branching and facilitated dissection of suprapyloric lymph nodes. The left gastric artery furnishing the aberrant left hepatic artery was successfully revealed and this information enabled us to avoid accidental hemorrhage and ischemic liver damage. Preoperative confirmation of the drainage routes of the left gastric vein was also useful in accomplishing secure lymphadenectomy.

CONCLUSIONS

3D-CT imaging provides a vascular "road map," which is critical for surgical guidance, and prevents the risks involved in surgery. Preoperative 3D-CT imaging may be an informative device to overcome the disadvantages of laparoscopic gastric cancer surgery.