Advanced gastric cancer and perfusion imaging using a multidetector row computed tomography: correlation with prognostic determinants

Predicting human epidermal growth factor receptor 2 status of patients with gastric cancer by computed tomography and clinical features

Background

There have been no studies on predicting human epidermal growth factor receptor 2 (HER2) status in patients with resectable gastric cancer (GC) in the neoadjuvant and perioperative settings. We aimed to investigate the use of preoperative contrast-enhanced computed tomography (CECT) imaging features combined with clinical characteristics for predicting HER2 expression in GC.

Methods

We retrospectively enrolled 301 patients with GC who underwent curative resection and preoperative CECT. HER2 status was confirmed by postoperative immunohistochemical analysis with or without fluorescence in situ hybridization. A prediction model was developed using CECT imaging features and clinical characteristics that were independently associated with HER2 status using multivariate logistic regression analysis. Receiver operating characteristic curves were constructed and the performance of the prediction model was evaluated. The bootstrap method was used for internal validation.

Results

Three CECT imaging features and one serum tumor marker were independently associated with HER2 status in GC: enhancement ratio in the arterial phase (odds ratio [OR] = 4.535; 95% confidence interval [CI], 2.220-9.264), intratumoral necrosis (OR = 2.64; 95% CI, 1.180-5.258), tumor margin (OR = 3.773; 95% CI, 1.968-7.235), and cancer antigen 125 (CA125) level (OR = 5.551; 95% CI, 1.361-22.651). A prediction model derived from these variables showed an area under the receiver operating characteristic curve of 0.802 (95% CI, 0.740-0.864) for predicting HER2 status in GC. The established model was stable, and the parameters were accurately estimated.

Conclusions

Enhancement ratio in the arterial phase, intratumoral necrosis, tumor margin, and CA125 levels were independently associated with HER2 status in GC. The prediction model derived from these factors may be used preoperatively to estimate HER2 status in GC and guide clinical treatment.

pT1-2 gastric cancer with lymph node metastasis predicted by tumor morphologic features on contrast-enhanced computed tomography

PURPOSE

To investigate the value of tumor morphologic features of pT1-2 gastric cancer (GC) on contrast-enhanced computed tomography (CT) in assessing lymph node metastasis (LNM) with reference to histopathological results.

METHODS

Eighty-six patients seen from October 2017 to April 2019 with pT1-2 GC proven by histopathology were included. Tumor volume and CT densities were measured in the plain scan and the portal-venous phase (PVP), and the percent enhancement was calculated. The correlations between tumor morphologic features and the N stages were analyzed. The diagnostic capability of tumor volume and enhancement features in predicting the LN status of pT1-2 GCs was further investigated using receiver operating characteristic (ROC) analysis.

RESULTS

Tumor volume, CT density in the PVP, and tumor percent enhancement in the PVP correlated significantly with the N stage (rho: 0.307, 0.558, and 0.586, respectively). Tumor volumes were significantly lower in the LNM- group than in the LNM+ group (14.4 mm3 vs. 22.6 mm3, P = 0.004). The differences between the LNM- and LNM+ groups in the CT density in the PVP and the percent enhancement in the PVP were also statistically significant (68.00 HU vs. 87.50 HU, P < 0.001; and 103.06% vs. 179.19%, P < 0.001, respectively). The area under the ROC curves for identifying the LNM+ group was 0.69 for tumor volume and 0.88 for percent enhancement in the PVP, respectively. The percent enhancement in the PVP of 145.2% and tumor volume of 17.4 mL achieved good diagnostic performance in determining LNM+ (sensitivity: 71.4%, 82.1%; specificity: 91.4%, 58.6%; and accuracy: 84.9%, 66.3%, respectively).

CONCLUSION

Tumor volume and percent enhancement in the PVP of pT1-2 GC could improve the diagnostic accuracy of LNM and would be helpful in image surveillance of these patients.

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.

Quantitative parameters in novel spectral computed tomography: Assessment of Ki-67 expression in patients with gastric adenocarcinoma

BACKGROUND

The level of Ki-67 expression has served as a prognostic factor in gastric cancer. The quantitative parameters based on the novel dual-layer spectral detector computed tomography (DLSDCT) in discriminating the Ki-67 expression status are unclear.

AIM

To investigate the diagnostic ability of DLSDCT-derived parameters for Ki-67 expression status in gastric carcinoma (GC).

METHODS

Dual-phase enhanced abdominal DLSDCT was performed preoperatively in 108 patients with gastric adenocarcinoma. Primary tumor monoenergetic CT attenuation value at 40-100 kilo electron volt (kev), the slope of the spectral curve (λ_HU), iodine concentration (IC), normalized IC (nIC), effective atomic number (Z^eff) and normalized Z^eff (nZ^eff) in the arterial phase (AP) and venous phase (VP) were retrospectively compared between patients with low and high Ki-67 expression in gastric adenocarcinoma. Spearman’s correlation coefficient was used to analyze the association between the above parameters and Ki-67 expression status. Receiver operating characteristic (ROC) curve analysis was performed to compare the diagnostic efficacy of the statistically significant parameters between two groups.

RESULTS

Thirty-seven and 71 patients were classified as having low and high Ki-67 expression, respectively. CT_{40 kev-VP}, CT_{70 kev-VP}, CT_{100 kev-VP}, and Z^eff-related parameters were significantly higher, but IC-related parameters were lower in the group with low Ki-67 expression status than the group with high Ki-67 expression status, and other analyzed parameters showed no statistical difference between the two groups. Spearman’s correlation analysis showed that CT_{40 kev-VP}, CT_{70 kev-VP}, CT_{100 kev-VP}, Z^eff, and nZ^eff exhibited a negative correlation with Ki-67 status, whereas IC and nIC had positive correlation with Ki-67 status. The ROC analysis demonstrated that the multi-variable model of spectral parameters performed well in identifying the Ki-67 status [area under the curve (AUC) = 0.967; sensitivity 95.77%; specificity 91.89%)]. Nevertheless, the differentiating capabilities of single-variable model were moderate (AUC value 0.630 - 0.835). In addition, the nZ^eff_VP and nIC_VP (AUC 0.835 and 0.805) showed better performance than CT_{40 kev-VP}, CT_{70 kev-VP} and CT_{100 kev-VP} (AUC 0.630, 0.631 and 0.662) in discriminating the Ki-67 status.

CONCLUSION

Quantitative spectral parameters are feasible to distinguish low and high Ki-67 expression in gastric adenocarcinoma. Z^eff and IC may be useful parameters for evaluating the Ki-67 expression.

Quantitative parameters in novel spectral computed tomography: Assessment of Ki-67 expression in patients with gastric adenocarcinoma

BACKGROUND

The level of Ki-67 expression has served as a prognostic factor in gastric cancer. The quantitative parameters based on the novel dual-layer spectral detector computed tomography (DLSDCT) in discriminating the Ki-67 expression status are unclear.

AIM

To investigate the diagnostic ability of DLSDCT-derived parameters for Ki-67 expression status in gastric carcinoma (GC).

METHODS

Dual-phase enhanced abdominal DLSDCT was performed preoperatively in 108 patients with gastric adenocarcinoma. Primary tumor monoenergetic CT attenuation value at 40-100 kilo electron volt (kev), the slope of the spectral curve (λ_HU), iodine concentration (IC), normalized IC (nIC), effective atomic number (Z^eff) and normalized Z^eff (nZ^eff) in the arterial phase (AP) and venous phase (VP) were retrospectively compared between patients with low and high Ki-67 expression in gastric adenocarcinoma. Spearman’s correlation coefficient was used to analyze the association between the above parameters and Ki-67 expression status. Receiver operating characteristic (ROC) curve analysis was performed to compare the diagnostic efficacy of the statistically significant parameters between two groups.

RESULTS

Thirty-seven and 71 patients were classified as having low and high Ki-67 expression, respectively. CT_{40 kev-VP}, CT_{70 kev-VP}, CT_{100 kev-VP}, and Z^eff-related parameters were significantly higher, but IC-related parameters were lower in the group with low Ki-67 expression status than the group with high Ki-67 expression status, and other analyzed parameters showed no statistical difference between the two groups. Spearman’s correlation analysis showed that CT_{40 kev-VP}, CT_{70 kev-VP}, CT_{100 kev-VP}, Z^eff, and nZ^eff exhibited a negative correlation with Ki-67 status, whereas IC and nIC had positive correlation with Ki-67 status. The ROC analysis demonstrated that the multi-variable model of spectral parameters performed well in identifying the Ki-67 status [area under the curve (AUC) = 0.967; sensitivity 95.77%; specificity 91.89%)]. Nevertheless, the differentiating capabilities of single-variable model were moderate (AUC value 0.630 - 0.835). In addition, the nZ^eff_VP and nIC_VP (AUC 0.835 and 0.805) showed better performance than CT_{40 kev-VP}, CT_{70 kev-VP} and CT_{100 kev-VP} (AUC 0.630, 0.631 and 0.662) in discriminating the Ki-67 status.

CONCLUSION

Quantitative spectral parameters are feasible to distinguish low and high Ki-67 expression in gastric adenocarcinoma. Z^eff and IC may be useful parameters for evaluating the Ki-67 expression.

Value of multiphase contrast-enhanced CT with three-dimensional reconstruction in detecting depth of infiltration, lymph node metastasis, and extramural vascular invasion of gastric cancer

Background

Multiphase contrast-enhanced computed tomography (CECT) can reveal the location, morphology, size, and enhancement pattern of gastric cancer (GC), whereas the three-dimensional reconstruction (3DR) technique can better display the relationships of the lesions with surrounding structures, the feeding vessels, and lymph node metastasis. Here, we investigated the value of multi-phase CECT with 3DR in detecting depth of infiltration, lymph node metastasis, and extramural vascular invasion (EMVI) of GC.

Methods

The clinical and imaging data of 132 GC patients admitted to the Chongqing Hospital of Traditional Chinese Medicine and the Third Affiliated Hospital of Chongqing Medical University during the period from January 2012 to October 2019 were collected. All patients received plain and multiphase contrast-enhanced CT scans. The agreement between the results of preoperative CT evaluation and the surgical/pathological findings was compared.

Results

(I) CT findings of GC of 3 differentiation levels: on the multiphase CECT, the peak enhancement percentage was highest in the portal venous phase. The CT values significantly differed among the arterial, portal venous, and equilibrium phases (P<0.05); the differences in the arterial, portal venous, and equilibrium phases were statistically significant among the well-, moderately, and poorly differentiated groups (all P<0.05); finally, the difference in the equilibrium phase was statistically significant between the well- and moderately differentiated groups (P<0.05). (II) Preoperative CT and postoperative pathology had good consistency in T staging (Kappa =0.667). (III) The Kappa values between the preoperative CT-diagnosed lymph node metastasis and postoperative pathologically showing an increasing consistency with the increase of CT enhancement differences. (IV) Preoperative CT and postoperative pathology had good consistency in N staging (Kappa =0.779). (V) Preoperative CT in displaying arterial supply to the stomach. The rate of positive EMVI was 32.6% (43/132) on preoperative CT. The positive EMVI diagnosed by preoperative CT was correlated with tumor size, growth pattern, tissue differentiation degree, T stage, and N stage (all P<0.05).

Conclusions

Multiphase CECT combined with 3DR has high diagnostic performance in detecting the depth of infiltration, lymph node metastasis, and EMVI of GC.

A meta-analysis of the utility of transabdominal ultrasound for evaluation of gastric cancer

BACKGROUND

Clinical discovery/staging of gastric cancer (GC) is crucial in designing the treatment strategies and largely decides GC patients' survival. Endoscopic ultrasonography (EUS) and computed tomography (CT) are 2 useful GC diagnosis tools. High doses of radiation associated with CT make its use limited, while the process of EUS is stressful, time-consuming, and challenging. Transabdominal ultrasound (TAUS) is a promising candidate to address these shortcomings. This study aimed to meta-analyze the diagnostic accuracy and sensitivity of TAUS in discriminating between advanced and early GCs, as well as compare its utility with other imaging techniques.Methods: Literature searches were conducted using PubMed, Web of Science, Embase, and Cochrane Library databases up to 2019. Data were analyzed using RevMan software (Cochrane Collaboration, Oxford, UK), and pooled estimates of accuracy, sensitivity, and other features were acquired. Seven papers were eventually selected for meta-analysis.

RESULTS

TAUS had distinct diagnostic efficacies for early and advanced GC patients. The accuracy and sensitivity were significantly higher in the advanced group. A high color Doppler vascularity index and a lesion larger than 1 cm were 2 features of advanced GC. Moreover, TAUS had a comparable (but slightly higher) accuracy than CT and EUS.

CONCLUSIONS

TAUS is more accurate and sensitive in diagnosing advanced GC compared to early GC. More features of advanced GC are required to improve the recognition ability. At least, TAUS can be considered as a complementary imaging diagnostic tool to CT and EUS.

Spectral CT in Lung Cancer: Usefulness of Iodine Concentration for Evaluation of Tumor Angiogenesis and Prognosis

OBJECTIVE. The purpose of this study was to investigate the correlation between iodine concentration (IC) derived from spectral CT and angiogenesis and the relationships between IC and clinical-pathologic features associated with lung cancer prognosis. SUBJECTS AND METHODS. Sixty patients with lung cancer were enrolled and underwent spectral CT. The IC, IC difference (ICD), and normalized IC (NIC) of tumors were measured in the arterial phase, venous phase (VP), and delayed phase. The microvessel densities (MVDs) of CD34-stained specimens were evaluated. Correlation analysis was performed for IC and MVD. The relationships between the IC index showing the best correlations with MVD and clinical-pathologic findings of pathologic types, histologic differentiation, tumor size, lymph node status, pathologic TNM stage, and intratumoral necrosis were investigated. RESULTS. The mean (± IQR) MVD of all tumors was 42.00 ± 27.50 vessels per field at ×400 magnification, with two MVD distribution types. The MVD of lung cancer correlated positively with the IC, ICD, and NIC on three-phase contrast-enhanced scanning (r range, 0.581-0.800; all p < 0.001), and the IC in the VP showed the strongest correlation with MVD (r = 0.800; p < 0.001). The correlations between IC and MVD, ICD and MVD, and NIC and MVD varied depending on whether the same scanning phase or same IC index was used. The IC in the VP showed statistically significant differences in the pathologic types of adenocarcinoma and squamous cell carcinoma, histologic differentiation, tumor size, and status of intratumoral necrosis of lung cancer (p < 0.05), but was not associated with nodal metastasis and pathologic TNM stages (p > 0.05). CONCLUSION. IC indexes derived from spectral CT, especially the IC in the VP, were useful indicators for evaluating tumor angiogenesis and prognosis.

Imaging biomarkers in upper gastrointestinal cancers

In parallel with the increasingly widespread availability of high performance imaging platforms and recent progresses in pathobiological characterisation and treatment of gastrointestinal malignancies, imaging biomarkers have become a major research topic due to their potential to provide additional quantitative information to conventional imaging modalities that can improve accuracy at staging and follow-up, predict outcome, and guide treatment planning in an individualised manner. The aim of this review is to briefly examine the status of current knowledge about imaging biomarkers in the field of upper gastrointestinal cancers, highlighting their potential applications and future perspectives in patient management from diagnosis onwards.

Dynamic Contrast-Enhanced Ultrasound of Gastric Cancer: Correlation with Perfusion CT and Histopathology

Objective

To assess the relationship between contrast-enhanced ultrasound (CEUS) parameters and perfusion CT (PCT) parameters of gastric cancers and their correlation with histologic features.

Materials and Methods

This prospective study was approved by our Institutional Review Board. We included 43 patients with pathologically-proven gastric cancers undergoing CEUS using SonoVue® (Bracco) and PCT on the same day. Correlation between the CEUS parameters (peak intensity [PI], area under the curve [AUC], rise time [RT] from 10% to 90% of PI, time to peak [TTP_US], and mean transit time [MTT_US]) and PCT parameters (blood flow, blood volume, TTP_CT, MTT_CT, and permeability surface product) of gastric cancers were analyzed using Spearman's rank correlation test. In cases of surgical resection, the CEUS and PCT parameters were compared according to histologic features using Mann-Whitney test.

Results

CEUS studies were of diagnostic quality in 88.4% (38/43) of patients. Among the CEUS parameters of gastric cancers, RT and TTP_US showed significant positive correlations with TTP_CT (rho = 0.327 and 0.374, p = 0.045 and 0.021, respectively); PI and AUC were significantly higher in well-differentiated or moderately-differentiated tumors (n = 4) than poorly-differentiated tumors (n = 18) (p = 0.026 and 0.033, respectively), whereas MTT_CT showed significant differences according to histologic types (poorly cohesive carcinoma [PCC] vs. non-PCC), T-staging (≤ T2 vs. ≥ T3), N-staging (N0 vs. N-positive), and epidermal growth factor receptor expression (≤ faint vs. ≥ moderate staining) (p values < 0.05).

Conclusion

In patients with gastric cancers, CEUS is technically feasible for the quantification of tumor perfusion and may provide correlative and complementary information to that of PCT, which may allow prediction of histologic features.

Prediction of Treatment Outcome of Chemotherapy Using Perfusion Computed Tomography in Patients with Unresectable Advanced Gastric Cancer

Objective

To evaluate whether data acquired from perfusion computed tomography (PCT) parameters can aid in the prediction of treatment outcome after palliative chemotherapy in patients with unresectable advanced gastric cancer (AGC).

Materials and Methods

Twenty-one patients with unresectable AGCs, who underwent both PCT and palliative chemotherapy, were prospectively included. Treatment response was assessed according to Response Evaluation Criteria in Solid Tumors version 1.1 (i.e., patients who achieved complete or partial response were classified as responders). The relationship between tumor response and PCT parameters was evaluated using the Mann-Whitney test and receiver operating characteristic analysis. One-year survival was estimated using the Kaplan-Meier method.

Results

After chemotherapy, six patients exhibited partial response and were allocated to the responder group while the remaining 15 patients were allocated to the non-responder group. Permeability surface (PS) value was shown to be significantly different between the responder and non-responder groups (51.0 mL/100 g/min vs. 23.4 mL/100 g/min, respectively; p = 0.002), whereas other PCT parameters did not demonstrate a significant difference. The area under the curve for prediction in responders was 0.911 (p = 0.004) for PS value, with a sensitivity of 100% (6/6) and specificity of 80% (12/15) at a cut-off value of 29.7 mL/100 g/min. One-year survival in nine patients with PS value > 29.7 mL/100 g/min was 66.7%, which was significantly higher than that in the 12 patients (33.3%) with PS value ≤ 29.7 mL/100 g/min (p = 0.019).

Conclusion

Perfusion parameter data acquired from PCT demonstrated predictive value for treatment outcome after palliative chemotherapy, reflected by the significantly higher PS value in the responder group compared with the non-responder group.

Evaluation of a multi-slice spiral computed tomography perfusion for the prediction of the recurrence of gastric cancer

AIM

The study aimed to elucidate the value of multislice spiral computed tomography (MSCT) perfusion for the early prediction of gastric cancer (GC) recurrence.

METHODS

MSCT perfusion scans were performed to obtain values pertaining to blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS). Logistic regression analysis was employed to evaluate the risk factors of postoperative recurrence in GC.

RESULTS

The maximum diameter of GC has a positive relationship with PS. The maximum enhancement of GC was positively correlated with BF, blood volume and PS. PS, BF, vascular thrombus and Tumor, Node, Metastasis staging were found to be significant risk factors in relation to the recurrence of GC (p = 0.006, p = 0.002, p < 0.001).

CONCLUSION

MSCT perfusion is strongly correlated with postoperative recurrence of GC, and PS and BF values, vascular thrombus and Tumor, Node, Metastasis staging were discovered as being prominent factors influencing the recurrence of GC.

Association between spectral computed tomography images and clinicopathological features in advanced gastric adenocarcinoma

To investigate the role of spectral computed tomography (CT)-generated iodine concentration (IC) in the evaluation of clinicopathological features of advanced gastric adenocarcinoma (AGC), 42 patients who underwent abdominal enhanced CT with spectral imaging mode were selected for the present study. The IC of the primary lesion in the arterial phase (IC_AP) and portal venous phase (IC_VP) was measured and the IC of the aorta was used for a normalized iodine concentration (nIC). Micro-vessel density (MVD) and lymphatic vessel density (LVD) were detected using immunohistochemical assays against cluster of differentiation 34 and D2-40, respectively. Other clinicopathological characteristics were also documented. The IC parameters were revealed to be significantly increased in the high-MVD group, particularly for the nIC_VP (P=0.002). Additionally, the nIC_AP revealed a significant difference (P=0.041) between the high- and low-LVD group. The nIC_AP and nIC_VP were increased in the poorly differentiated group compared with the moderately differentiated group (P=0.040 and P=0.011, respectively). The ICs and MVD demonstrated a statistically significant positive linear correlation. nIC_VP was able to be used to discriminate between the moderately and poorly differentiated carcinomas, with an area under the receiver operating characteristic curve of 0.759. However, IC demonstrated no correlation with serosal involvement, lymph node metastasis, LVD, and nodular or metastatic tumors. The results of the present study suggest that the nIC_VP value may serve as a non-invasive marker for the angiogenesis of, and the differentiations between, patients with AGC.

Iodine Concentration in Spectral CT: Assessment of Prognostic Determinants in Patients With Gastric Adenocarcinoma

OBJECTIVE

The purpose of this study was to use virtual monochromatic spectral CT to investigate the usefulness of iodine concentration (IC) and its correlation with clinicopathologically determined prognostic factors in gastric adenocarcinoma.

SUBJECTS AND METHODS

From June 2012 to March 2015, 34 patients with gastric adenocarcinoma underwent arterial and portal venous phase spectral CT. The ICs in the arterial and portal venous phases were calculated and then normalized with the aorta as normalized IC (NIC). The surgical specimen was evaluated with CD34 staining to determine microvessel density (MVD). The correlation between imaging results and clinicopathologic findings was investigated for histologic grading, lymph node metastasis, serosal involvement, distant metastasis, pathologic TNM stage, and MVD.

RESULTS

The mean arterial phase NIC value of tumors was 0.12 ± 0.03, portal venous phase NIC value was 0.39 ± 0.06, and MVD was 26.94 ± 7.87 vessels per high-power field (×400). Both arterial phase and portal venous phase NIC values were significantly higher in poorly differentiated gastric adenocarcinomas (p = 0.005) than in moderately differentiated tumors (p = 0.013). There was no significant correlation between NIC and serosal involvement or distant metastasis. There was significant correlation between the NIC and MVD in gastric adenocarcinoma (arterial phase NIC, p = 0.013; portal venous phase NIC, p = 0.001). However, neither the arterial nor the portal venous phase NIC of gastric adenocarcinoma had a significant relation to lymphatic metastasis or pathologic TNM stage. There was a significant difference between the high and low MVD groups with respect to portal venous phase NIC (p = 0.045).

CONCLUSION

NIC can serve as a useful predictor of angiogenesis and degree of differentiation of moderately and poorly differentiated gastric adenocarcinomas.

CT Perfusion evaluation of gastric cancer: correlation with histologic type

OBJECTIVES

To prospectively evaluate if the perfusion parameters of gastric cancer can provide information on histologic subtypes of gastric cancer.

METHODS

We performed preoperative perfusion CT (PCT) and curative gastrectomy in 46 patients. PCT data were analysed using a dedicated software program. Perfusion parameters were obtained by two independent radiologists and were compared according to histologic type using Kruskal-Wallis, Mann-Whitney U test and receiver operating characteristic analysis. To assess inter-reader agreement, we used intraclass correlation coefficient (ICC).

RESULTS

Inter-reader agreement for perfusion parameters was moderate to substantial (ICC = 0.585-0.678). Permeability surface value of poorly cohesive carcinoma (PCC) was significantly higher than other histologic types (47.3 ml/100 g/min in PCC vs 26.5 ml/100 g/min in non-PCC, P < 0.001). Mean transit time (MTT) of PCC was also significantly longer than non-PCC (13.0 s in PCC vs 10.3 s in non-PCC, P = 0.032). The area under the curve to predict PCC was 0.891 (P < 0.001) for permeability surface and 0.697 (P = 0.015) for MTT.

CONCLUSION

Obtaining perfusion parameters from PCT was feasible in gastric cancer patients and can aid in the preoperative imaging diagnosis of PCC-type gastric cancer as the permeability surface and MTT value of PCC type gastric cancer were significantly higher than those of non-PCC.

KEY POINTS

• Obtaining perfusion parameters from PCT was feasible in patients with gastric cancer. • Permeability surface and MTT were significantly higher in poorly cohesive carcinoma (PCC). • Permeability surface, MTT can aid in the preoperative imaging diagnosis of PCC.

Spectral computed tomography in advanced gastric cancer: Can iodine concentration non-invasively assess angiogenesis?

AIM

To investigate the correlation of iodine concentration (IC) generated by spectral computed tomography (CT) with micro-vessel density (MVD) and vascular endothelial growth factor (VEGF) expression in patients with advanced gastric carcinoma (GC).

METHODS

Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase (AP) and venous phase (VP) were measured, and were then normalized against that in the aorta to provide the normalized IC (nIC). MVD and VEGF were detected by immunohistochemical assays, using CD34 and VEGF-A antibodies, respectively. Correlations of nIC with MVD, VEGF, and clinical-pathological features were analyzed.

RESULTS

Both nICs correlated linearly with MVD and were higher in the primary lesion site than in the normal control site, but were not correlated with VEGF expression. After stratification by clinical-pathological subtypes, nIC-AP showed a statistically significant correlation with MVD, particularly in the group with tumors at stage T4, without nodular involvement, of a mixed Lauren type, where the tumor was located at the antrum site, and occurred in female individuals. nIC-VP showed a positive correlation with MVD in the group with the tumor at stage T4 and above, had nodular involvement, was poorly differentiated, was located at the pylorus site, of a mixed and diffused Lauren subtype, and occurred in male individuals. nIC-AP and nIC-VP showed significant differences in terms of histological differentiation and Lauren subtype.

CONCLUSION

The IC detected by spectral CT correlated with the MVD. nIC-AP and nIC-VP can reflect angiogenesis in different pathological subgroups of advanced GC.

CT perfusion imaging of the stomach: a quantitative analysis according to different degrees of adenocarcinoma cell differentiation

OBJECTIVES

To evaluate clinical usefulness of computed tomography perfusion imaging (CTPI) in gastric cancer.

MATERIALS AND METHODS

Twenty subjects without gastric diseases (control group) and fifty patients with gastric cancer were studied prospectively using CTPI examinations. Four perfusion parameter values, i.e., blood flow (BF), blood volume (BV), mean transit time, and permeability surface (PS), were calculated. The gastric cancer group was divided into three groups: well differentiated, moderately differentiated, and poorly differentiated gastric adenocarcinoma.

RESULTS

Comparing the three groups, differences between the well-differentiated group and the moderately differentiated group or the poorly differentiated group were all statistically significant for BF, BV, and PS.

CONCLUSION

The BF, BV, and PS values could serve as indicators of the degree of malignancy of gastric cancer.

Dynamic contrast-enhanced MRI of gastric cancer: Correlation of the perfusion parameters with pathological prognostic factors

PURPOSE

To investigate the feasibility of dynamic, contrast-enhanced, magnetic resonance imaging (DCE-MRI) for perfusion quantification of gastric cancers, and to correlate the DCE-MRI parameters with the pathological prognostic factors.

MATERIALS AND METHODS

This prospective study was approved by our Institutional Review Board. Twenty-seven patients with gastric cancers underwent DCE-MRI using a free-breathing, radial, gradient-echo (GRE) sequence with k-space weighted image contrast (KWIC) reconstruction on a 3T scanner. The DCE-MRI parameters (volume transfer coefficient [K(trans) ], reverse reflux rate constant [Kep ], extracellular extravascular volume fraction [Ve ], and initial area under the gadolinium concentration curve during the first 60 seconds [iAUC]) of gastric cancer and normal wall were measured and compared with each other using the Wilcoxon signed rank test. The relationship between the DCE-MRI parameters of gastric cancer and the pathological prognostic factors were evaluated using the Mann-Whitney test or the Spearman rank correlation test.

RESULTS

DCE-MRIs were of diagnostic quality in 22 patients (81.5%). Ve and iAUC were significantly higher in gastric cancer than in normal gastric wall (P < 0.05). Ve showed significant positive correlation with T-staging of gastric cancers (P < 0.05). K(trans) was significantly correlated with the grades of epidermal growth-factor receptor expression (P < 0.05).

CONCLUSION

DCE-MRI using a radial GRE with KWIC reconstruction is feasible for quantification of the perfusion dynamics of gastric cancers, and the DCE-MRI parameters of gastric cancers may provide prognostic information.

Diagnostic value of CT perfusion imaging for parotid neoplasms

OBJECTIVES

To assess the value of CT perfusion imaging in the differentiation of different histological categorization of benign tumours from malignant tumours in patients with parotid neoplasms.

METHODS

CT perfusion was successfully performed in 62 patients with parotid neoplasms whose diagnoses were confirmed by surgery or biopsy. The software generated a tissue time-density curve (TDC) and measured blood volume, blood flow, mean transit time and capillary permeability surface product. One-way ANOVA and receiver operating characteristic curves were used to analyse the difference and diagnostic efficacies of all perfusion data between each one of the benign tumours and malignancies. Statistical significance was assigned at the 5% level.

RESULTS

Pleomorphic adenomas mainly had a gradually ascending TDC. Warthin tumours showed a fast ascent followed by a fast descent. The TDC of basal cell adenomas had a fast ascension followed by a plateau, then a gradual descent. Malignant tumours mainly showed a rapidly ascending curve with a stable plateau. Significant differences were observed in blood flow, blood volume and mean transit time between pleomorphic adenomas and malignant tumours (p < 0.05) as well as in blood flow and blood volume between the Warthin tumours, the basal cell adenomas and the malignant tumours (p < 0.05). Differences in permeability surface between the basal cell adenomas and malignant tumours were significant (p < 0.01).

CONCLUSION

CT perfusion of parotid gland could provide TDC and perfusion data, which were useful in the differentiation of different histological benign tumours and malignant tumours in the parotid gland.

Gastric cancer staging with dual energy spectral CT imaging

Purpose

To evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers.

Materials and Methods

96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings.

Results

The overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP.

Conclusion

The monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes.

Grading of uterine cervical cancer by using the ADC difference value and its correlation with microvascular density and vascular endothelial growth factor

OBJECTIVE

To investigate the application value of the ADC(difference) value in evaluating the pathological grade of uterine cervical cancer and to analyse the correlations among microvascular density (MVD), vascular endothelial growth factor (VEGF) expression and maximum ADC(difference) value.

METHODS

Fifty-six patients with uterine cervical cancer were included in this prospective study. All underwent conventional MRI and DWI. MVD and VEGF were evaluated by immunohistochemical staining with anti-CD34 and anti-VEGF, respectively.

RESULTS

Maximum ADC(difference) value and MVD count showed statistical differences among different pathological grades (P < 0.001, P < 0.001). There was a significant positive linear correlation between the maximum ADC(difference) value and pathological tumour grade (P < 0.001), and also between MVD count and pathological tumour grade (P < 0.001). No significant differences were found between the level of VEGF expression and pathological tumour grade (P = 0.222). The maximum ADC(difference) value correlated positively with both the MVD count and the level of VEGF expression (P < 0.001, P < 0.001).

CONCLUSIONS

Quantitative analysis of maximum ADC(difference) value of uterine cervical cancer may represent the grade of tumour differentiation and provide valuable information on tumour microcirculation and perfusion, thus allowing a promising new method of non-invasively assessing the pathological grade, which could serve as a substitution for assessing tumour angiogenesis.

Gastric adenocarcinoma: can perfusion CT help to noninvasively evaluate tumor angiogenesis?

BACKGROUND

Perfusion CT is an attractive technique to assess tumor vascularity, and no studies have addressed the relationship between CT perfusion imaging and gastric tumor angiogenesis with volume-based technique. This study aims to assess the correlation between perfusion CT parameters using a volume-based technique and immunohistochemical markers of angiogenesis in gastric adenocarcinoma.

METHODS

37 patients with gastric adenocarcinoma who completed whole tumor CT perfusion examination with volume-based technique were studied. Post surgical specimens were stained using a polyclonal antibody to VEGF and CD34. Perfusion measurements were correlated with microvessel density (MVD) and VEGF by using Pearson or Spearman rank correlation analysis, in which a P value < 0.05 was considered statistically significant.

RESULTS

The mean MVD of all 37 tumors was 108.9 ± 38.2 vessels/0.723 mm². 70.3% (26 of 37) of tumors expressed VEGF positively. MVD of gastric adenocarcinoma was significantly correlated with blood volume (the Pearson correlation coefficient being 0.420, P = 0.001). No correlations were found between VEGF expression and perfusion CT parameters. There were no significant differences in the parameters between the high and low MVD groups, and between the positive and negative VEGF groups.

CONCLUSIONS

Blood volume was significantly correlated with MVD. It could reflect the angiogenesis in gastric adenocarcinoma.

Recent advances in preoperative staging of gastric cancer

A more differentiated therapy regimen for gastric carcinoma requires more precise preoperative staging. In patients with early gastric cancer (EGC), especially in cases with carcinoma confined to mucosa, endoscopic resection (ER) is usually performed to avoid unnecessary surgical procedures. To achieve R0 resection for locally advanced gastric cancer (AGC), neoadjuvant treatments have been investigated. Clinical staging of gastric cancer has been greatly improved by advances in imaging techniques, such as endoscopic ultrasonography (EUS), transabdominal ultrasonography (TAUS), multi-slice spiral CT (MSCT), magnetic resonance imaging (MRI), positron emission tomography (PET), combined PET-CT scans, and laparoscopic staging. This paper aims to summarize the recent advances in preoperative staging of gastric cancer.

Perfusion changes in gastric adenocarcinoma: evaluation with 64-section MDCT

BACKGROUND

Perfusion CT has been applied in many clinical areas, but few studies have addressed gastric cancer. This study is to investigate the feasibility of first-pass perfusion CT with volume-based technique to assess microcirculation of gastric adenocarcinoma.

METHODS

Perfusion CT of gastric adenocarcinoma was performed with 64-section MDCT in 58 patients, which were subdivided into three subgroups according to the location of the tumor. Perfusion, peak enhancement, time to peak, and blood volume were computed in the tumor and in normal gastric wall. Mean values of perfusion parameters were compared between the tumor and normal stomach, between tumors with and without lymph node metastases, and between different stages.

RESULTS

Blood volume was significantly increased in gastric adenocarcinoma compared with normal stomach (19.75 +/- 14.74 vs. 13.59 +/- 11.46 mL/100 g, in total stomach, P = 0.004). A total of 10.55 mL/100 g of blood volume was employed as the cut-off value to discriminate the microcirculation of the tumor from that of the normal stomach. There were no significant differences of any perfusion parameters between the subgroups with and without lymph node metastases, or between early and advanced cancer.

CONCLUSIONS

The first-pass perfusion CT with whole tumor acquisition technique is a feasible technique for quantifying tumor vascularity and angiogenesis in gastric adenocarcinoma.

First-pass perfusion computed tomography: initial experience in differentiating adrenal adenoma from metastasis

OBJECTIVE

To differentiate adrenal adenoma from metastasis in patients using perfusion computed tomography (PCT) imaging.

METHODS

Thirty-two patients with adrenal masses underwent first-pass PCT imaging. Of these patients, twenty-one were diagnosed with adrenal adenoma, and the others with metastases. Perfusion maps of blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface-area production (PS) were generated with an Advantage Windows workstation using the CT perfusion 3.0 software (General Electric Medical Systems, Milwaukee, WI). Histopathologic sections immunostained for CD34 were quantitatively evaluated for microvessel density (MVD).

RESULTS

The perfusion parameters such as BV, BF and PS were statistically significant different between the two groups, with adenomas showing higher mean BV (12.18 versus 3.86), BF (97.51 versus 45.99) and PS (21.73 versus 10.93) compared with metastases (p<0.05). For BV, a cutoff point of 7.30 was found to have a sensitivity of 95.2% and a specificity of 100% to differentiate between adenoma and metastasis. The sensitivity and specificity were 81.0 and 80.0%, respectively, for BF with a cutoff point of 71.96; and 85.7 and 86.7%, respectively, for PS with a cutoff point of 12.70 to differentiate adenoma and metastasis. A comparison of MVD counts from adenomas with those from metastases showed a significant difference (p<0.05). However, no significant differences were observed in the four perfusion parameters and MVD between lipid rich and lipid poor adenomas.

CONCLUSION

PCT may be useful for evaluating the neovascularization of adrenal masses and differentiating adenoma from metastasis on the basis of PCT parameters. Adenomas show higher BV, BF and PS compared with metastases. According our data, the optimal threshold BV is 7.30, resulting in a sensitivity of 95.2% and a specificity of 100% for the differentiation of adenoma from metastasis. Adrenal adenomas have similar hemodynamic profiles, which are apparently independent of the lipid content of an adenoma.