Clinical value of magnetic resonance imaging in preoperative T staging of gastric cancer and postoperative pathological diagnosis

Clinical application of oral contrast-enhanced ultrasound in evaluating the preoperative T staging of gastric cancer

BACKGROUND

Oral contrast-enhanced ultrasound (OCEUS) is widely used in the noninvasive diagnosis and screening of gastric cancer (GC) in China.

AIM

To investigate the clinical application of OCEUS in evaluating the preoperative T staging of gastric cancer.

METHODS

OCEUS was performed before the operation, and standard ultrasound images were retained. The depth of infiltration of GC (T-stage) was evaluated according to the American Joint Committee on Cancer 8th edition of the tumor-node-metastasis staging criteria. Finally, with postoperative pathological staging as the gold standard reference, the sensitivity, specificity, negative predictive value, positive predictive value, and diagnostic value of OCEUS T staging were evaluated.

RESULTS

OCEUS achieved diagnostic accuracy rates of 76.6% (T1a), 69.6% (T1b), 62.7% (T2), 60.8% (T3), 88.0% (T4a), and 88.7% (T4b), with an average of 75.5%. Ultrasonic T staging sensitivity exceeded 62%, aside from T1b at 40.3%, while specificity was over 91%, except for T3 with 83.5%. The Youden index was above 60%, with T1b and T2 being exceptions. OCEUS T staging corresponded closely with pathology in T4b (kappa > 0.75) and moderately in T1a, T1b, T2, T3, and T4a (kappa 0.40-0.75), registering a concordance rate exceeding 84%.

CONCLUSION

OCEUS was effective, reliable, and accurate in diagnosing the preoperative T staging of GC. As a noninvasive diagnostic technique, OCEUS merits clinical popularization.

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.

Predicting T and N Staging of Resectable Gastric Cancer According to Whole Tumor Histogram Analysis About a Non-Cartesian k-Space Acquisition DCE-MRI: A Feasibility Study

Objective

To explore the feasibility of the whole tumor histogram analysis parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) based on stack-of stars (StarVIBE) to predict T and N staging of resectable gastric cancer (GC).

Methods

Eighty-seven patients confirmed as GC by histopathology were enrolled in this prospective study. DCE-MRI were performed before surgery, and quantitative DCE parameters (K^trans, K_ep, V_e) and histogram metrics (Skewness, Kurtosis and Entropy) were measured by Omni-Kinetics software. Intraclass correlation coefficient (ICC) testing was used to determine the consistency of K^trans, K_ep and V_e values and histogram metrics values between two radiologists using Bland–Altman analysis. The quantitative DCE parameters or histogram metrics values between T stage or N stage were compared using ANOVA or Kruskal–Wallis testing. Receiver operating characteristic (ROC) analyses was performed to find out the best parameters for identifying T and N staging.

Results

There was statistical difference in K^trans, K_ep, V_e and entropy to identify T staging (P=0.015, 0.033, <0.001, and 0.007, respectively), and in pairwise comparisons of V_e values showed statistically difference between T1+2 and T3 group (P<0.001), T1+2 and T4 group (P<0.001). There were statistical differences in V_e to identify N staging (P=0.041). In ROC analysis, V_e was the best parameter for identifying T staging (AUC: 0.788, the sensitivity and specificity was 0.929 and 0.578, respectively) and N staging (AUC: 0.590, the sensitivity and specificity was 0.714 and 0.899, respectively).

Conclusion

The whole tumor histogram analysis parameters derived from StarVIBE DCE-MRI may be able to quantitatively evaluate T and N staging of GC, so as to help clinical treatment decision optimization.

Differentiating T1a-T1b from T2 in gastric cancer lesions with three different measurement approaches based on contrast-enhanced T1W imaging at 3.0 T

Background

To explore the diagnostic value of three different measurement approaches in differentiating T1a–T1b from T2 gastric cancer (GC) lesions.

Methods

A total of 95 consecutive patients with T1a–T2 stage of GC who performed preoperative MRI were retrospectively enrolled between January 2017 and November 2020. The parameters MRI T stage (subjective evaluation), thickness, maximum area and volume of the lesions were evaluated by two radiologists. Specific indicators including AUC, optimal cutoff, sensitivity, specificity, accuracy, positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV) and negative predictive value (NPV) of MRI T stage, thickness, maximum area and volume for differentiating T1a–T1b from T2 stage lesions were calculated. The ROC curves were compared by the Delong test. Decision curve analysis (DCA) was used to evaluate the clinical benefit.

Results

The ROC curves for thickness (AUC = 0.926), maximum area (AUC = 0.902) and volume (AUC = 0.897) were all significantly better than those of the MRI T stage (AUC = 0.807) in differentiating T1a–T1b from T2 lesions, with p values of 0.004, 0.034 and 0.041, respectively. The values corresponding to the thickness (including AUC, sensitivity, specificity, accuracy, PPV, NPV, PLR and NLR) were all higher than those corresponding to the MRI T stage, maximum area and volume. The DCA curves indicated that the parameter thickness could provide the highest clinical benefit if the threshold probability was above 35%.

Conclusions

Thickness may provide an efficient approach to rapidly distinguish T1a–T1b from T2 stage GC lesions.

Gastric Cancer: Epidemiology, Risk Factors, Classification, Genomic Characteristics and Treatment Strategies

Gastric cancer (GC) is one of the most common malignancies worldwide and it is the fourth leading cause of cancer-related death. GC is a multifactorial disease, where both environmental and genetic factors can have an impact on its occurrence and development. The incidence rate of GC rises progressively with age; the median age at diagnosis is 70 years. However, approximately 10% of gastric carcinomas are detected at the age of 45 or younger. Early-onset gastric cancer is a good model to study genetic alterations related to the carcinogenesis process, as young patients are less exposed to environmental carcinogens. Carcinogenesis is a multistage disease process specified by the progressive development of mutations and epigenetic alterations in the expression of various genes, which are responsible for the occurrence of the disease.

Diagnostic performance in T staging for patients with esophagogastric junction cancer using high-resolution MRI: a comparison with conventional MRI at 3 tesla

BACKGROUND

To investigate and compare the diagnostic performance in T staging for patients with esophagogastric junction cancer using high-resolution magnetic resonance imaging (HR MRI), as compared with conventional MRI at 3 Tesla.

METHODS

A total of 118 patients with pathologically confirmed esophagogastric junction cancer were included and underwent multiparameter HR MRI (Cohort 1, 62 patients) or conventional MRI (Cohort 2, 56 patients). T2-weighted, T1-weighted, diffusion-weighted and contrast-enhanced T1-weighted images of each patient were evaluated by two radiologists who determined the preoperative T staging by consensus. Using pathologic staging as the gold standard, the consistency between HR MRI and pathology and between conventional MRI and pathology in T staging was calculated and compared. The overall accuracy, overstatement and understatement of HR MRI and conventional MRI in T staging of patients with esophagogastric junction cancer were computed and compared. Moreover, the diagnostic performance of HR MRI and conventional MRI in T staging (≤ T1 and ≥ T4) of patients with esophagogastric junction cancer were evaluated.

RESULTS

There were no significant differences in age (p = 0.465) and sex (p = 0.175) between Cohorts 1 and 2. Excellent agreement was observed in the T staging of patients with esophagogastric junction cancer between pathology and HR MRI (kappa = 0.813), while moderate agreement was observed between pathology and conventional MRI (kappa = 0.486). Significant differences were observed in overall accuracy (88.7% vs 64.3%, p = 0.002) and understatement (1.6% vs 26.8%, p < 0.001) but not for overstatement (9.7% vs 8.9%, p = 0.889) in T staging between HR MRI and conventional MRI techniques. For differentiating the T stages of ≤ T1 from ≥ T2 and the T stages of ≤ T3 from ≥ T4, no significant differences were observed between the imaging techniques.

CONCLUSIONS

HR MRI has good diagnostic performance and may serve as an alternative technique in the T staging of patients with esophagogastric junction cancer in clinical practice.

Imaging strategies in the management of gastric cancer: current role and future potential of MRI

Accurate preoperative staging of gastric cancer and the assessment of tumor response to neoadjuvant treatment is of importance for treatment and prognosis. Current imaging techniques, mainly endoscopic ultrasonography (EUS), computed tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET), have their limitations. Historically, the role of magnetic resonance imaging (MRI) in gastric cancer has been limited, but with the continuous technical improvements, MRI has become a more potent imaging technique for gastrointestinal malignancies. The accuracy of MRI for T- and N-staging of gastric cancer is similar to EUS and CT, making MRI a suitable alternative to other imaging strategies. There is limited evidence on the performance of MRI for M-staging of gastric cancer specifically, but MRI is widely used for diagnosing liver metastases and shows potential for diagnosing peritoneal seeding. Recent pilot studies showed that treatment response assessment as well as detection of lymph node metastases and systemic disease might benefit from functional MRI (e.g. diffusion weighted imaging and dynamic contrast enhancement). Regarding treatment guidance, additional value of MRI might be expected from its role in better defining clinical target volumes and setup verification with MR-guided radiation treatment.

Predicting the nodal status in gastric cancers: The role of apparent diffusion coefficient histogram characteristic analysis

PURPOSE

To explore the application of histogram analysis in preoperative T and N staging of gastric cancers, with a focus on characteristic parameters of apparent diffusion coefficient (ADC) maps.

MATERIALS AND METHODS

Eighty-seven patients with gastric cancers underwent diffusion weighted magnetic resonance imaging (b=0, 1000s/mm²), which generated ADC maps. Whole-volume histogram analysis was performed on ADC maps and 7 characteristic parameters were obtained. All those patients underwent surgery and postoperative pathologic T and N stages were determined.

RESULTS

Four parameters, including skew, kurtosis, s-sD_av and sample number, showed significant differences among gastric cancers at different T and N stages. Most parameters correlated with T and N stages significantly and worked in differentiating gastric cancers at different T or N stages. Especially skew yielded a sensitivity of 0.758, a specificity of 0.810, and an area under the curve (AUC) of 0.802 for differentiating gastric cancers with and without lymph node metastasis (P<0.001). All the parameters, except AUC_low, showed good or excellent inter-observer agreement with intra-class correlation coefficients ranging from 0.710 to 0.991.

CONCLUSION

Characteristic parameters derived from whole-volume ADC histogram analysis could help assessing preoperative T and N stages of gastric cancers.

Diffusion-weighted whole-body imaging with background body signal suppression/T2-weighted image fusion of gastrointestinal cancers

Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) yields positive results for cancer against the surrounding tissues. The combination of DWIBS and T2-weighted images (DWIBS/T2) in the diagnosis of gastrointestinal tract cancers was retrospectively analyzed in the present study. Patients were subjected to magnetic resonance imaging after cancer was diagnosed through specimens obtained via biopsy or endoscopic mucosal resection. Sixteen patients were assessed between July, 2012 and June, 2013 and the correlation between detection with DWIBS/T2 and T staging was analyzed. Regarding patients who underwent surgery, the correlation between detection with DWIBS/T2 and the diameter or depth of invasion was analyzed. All cancers that had advanced to >T2 stage were detectable by DWIBS/T2, whereas all cancers staged as <T1 were not (P<0.0001). Tumors that were undetected by DWIBS/T2 had a mean diameter of 1.53±0.25 cm, whereas those detected had a mean diameter of 3.63±1.88 cm; however, the difference was not statistically significant (P=0.1053). Cancers invading beyond the muscularis propria were detectable by DWIBS/T2, while those which had not invaded the mucosa were not (P=0.0476). In conclusion, DWIBS/T2 was able to positively identify gastrointestinal tract cancers at an advanced stage (>T2) or invading beyond the muscularis propria.

Advances in imaging of gastric cancer

Due to the advances in imaging technology, the diagnosis, staging, and efficacy evaluation of gastric cancer by imaging are continuously improving. This paper comprehensively analyzes different imaging methods in cancer research, focusing on new imaging techniques for the diagnosis and treatment of gastric cancer, their advantages and limitations in clinical application, and the opportunities and challenges. Radiologists can take the initiative to collaborate with relevant clinical departments through a multidisciplinary platform with an open mind in the face of various problems presented clinically, understand the requirements for standardized diagnosis and treatment of gastric cancer, and fully communicate with imaging equipment providers and engineering and technical personnel to explore more methods and indicators to improve the diagnosis of this malignancy.