Prognostic Role of Diffusion-weighted MR Imaging for Resectable Gastric Cancer

Apparent Diffusion Coefficient Value as a Biomarker for Detecting Muscle-Invasive and High-Grade Bladder Cancer: A Systematic Review

Background: Several studies have investigated the potential role of the apparent diffusion coefficient (ADC) value of diffusion-weighted magnetic resonance imaging as a biomarker of high-grade and invasive bladder cancer. Methods: PubMed and the Cochrane Library were systematically searched in September 2021 to extract studies that evaluated the associations between ADC values, pathological T stage, and histological grade bladder cancers. The diagnostic performance of ADC values in detecting muscle-invasive bladder cancer (MIBC) and high-grade disease was systematically reviewed. Results: Six studies were included in this systematic review. MIBC showed significantly lower ADC values than non-muscle-invasive bladder cancer (NMIBC) in all six studies. The median (range) sensitivity, specificity, and area under the curve (AUC) of ADC values to detect MIBC among the four eligible studies were 73.5% (68.8–90.0%), 79.9% (66.7–84.4%), and 0.762 (0.730–0.884), respectively. Similarly, high-grade disease showed significantly lower ADC values than did low-grade disease in all four eligible studies. The median (range) sensitivity, specificity, and AUC of ADC values for detecting high-grade disease among the three eligible studies were 75.0% (73.0–76.5%), 95.8% (76.2–100%), and 0.902 (0.804–0.906), respectively. Conclusions: The ADC value is a non-invasive diagnostic biomarker for discriminating muscle-invasive and high-grade bladder cancer.

In vivo assessment of Lauren classification for gastric adenocarcinoma using diffusion MRI with a fractional order calculus model

OBJECTIVES

To evaluate the performance of a fractional order calculus (FROC) diffusion model for imaging-based assessment of Lauren classification in gastric adenocarcinoma.

METHODS

In this study, 43 patients (15 females, 28 males) with gastric adenocarcinoma underwent MRI at 1.5 T. According to pathology-based Lauren classification, 10 patients had diffuse-type, 20 had intestinal-type, and 13 had mixed-type lesions. The diffuse and mixed types were combined as diffuse-and-mixed type to be differentiated from the intestinal type using diffusion MRI. Diffusion-weighted images were acquired by using eleven b-values (0-2000 s/mm²). Three FROC model parameters comprising diffusion coefficient D, intravoxel diffusion heterogeneity β, and a microstructural quantity μ, together with a conventional apparent diffusion coefficient (ADC), were estimated. The mean parameter values in the tumour were computed by using a percentile histogram analysis. Individual or linear combinations of the mean parameters in the tumour were used to differentiate the diffuse-and-mixed type from the intestinal type using descriptive statistics and receiver operating characteristic (ROC) analyses.

RESULTS

Significant differences were observed between diffuse-and-mixed-type and intestinal-type lesions in D (0.99 ± 0.20 μm²/ms vs. 1.11 ± 0.23 μm²/ms; p = 0.036), β (0.37 ± 0.08 vs. 0.43 ± 0.11; p = 0.043), μ (7.92 ± 2.79 μm vs. 9.87 ± 1.52 μm; p = 0.038), and ADC (0.81 ± 0.34 μm²/ms vs. 0.96 ± 0.19 μm²/ms; p = 0.033). Among the individual parameters, μ produced the largest area under the ROC curve (0.739). The combinations of (D, β, μ) and (β and μ) produced the best overall performance with a sensitivity of 0.739, specificity of 0.750, accuracy of 0.744, and area under the curve of 0.793 (95% confidence interval: 0.657-0.929).

CONCLUSION

Diffusion MRI with the FROC model holds promise for non-invasive assessment of Lauren classification for gastric adenocarcinoma.

KEY POINTS

• High b-value diffusion MRI with a FROC model that is sensitive to tissue microstructures can differentiate the diffuse-and-mixed type from intestinal type of gastric adenocarcinoma. • The combination of FROC parameters produced the best result for distinguishing the diffuse-and-mixed type from the intestinal type with an area under the receiver operating characteristic curve of 0.793. • The FROC model parameters, individually or conjointly, hold promise for repeated, non-invasive evaluations of gastric adenocarcinoma at various time points throughout disease progression or regression to complement conventional Lauren classification.

Use of Diffusion-Weighted Magnetic Resonance Imaging and Apparent Diffusion Coefficient in Gastric Cancer Staging

BACKGROUND

The apparent diffusion coefficient (ADC), the quantitative parameter of diffusion-weighted magnetic resonance imaging (DW-MRI), is a measure for this restricted diffusion, and its role in gastric cancer (GC) including distinguishing malignant segments from healthy gastric wall, metastatic perigastric lymph nodes from benign nodes and evaluating response of GC to neoadjuvant chemotherapy has been investigated in previous studies. Evidence suggests that ADC may also be of help in assessment of aggressiveness and preoperative staging of gastric cancer, which needs to be explored in further studies.

OBJECTIVE

To investigate the role of DW-MRI and its quantitative parameter, ADC in staging of gastric cancer.

METHODS

Forty-six patients (28 male, 18 female, mean age 62 years) with non-metastatic biopsy- proven GC who underwent abdominal DW-MRI before surgery were included in this retrospective study. Tumor invasion depth (T-stage) and nodal involvement (N-stage) were evaluated using signal increase on DW-MRI, and tumor ADC was measured. Diagnostic performance of these results was assessed by comparing them with postsurgical histopathology based on 8th TNM classification.

RESULTS

Sensitivity, specificity, and accuracy of DW-MRI in T-staging were 92.1%, 75%, 89.1% for ≤T2 vs. ≥T3; and 75%, 88.5%, 82.6% for ≤T3 vs. T4. However, sensitivity, specificity, and accuracy of DW-MRI in N-staging were 89.3%, 88.9%, 89.1% for ≤N1 vs. ≥N2; and 73.7%, 96.3%, 86.9% for ≤N2 vs. N3, respectively. Relative preoperative ADC values correlated with pT staging (r=-0.397, p=0.006). There was also a statistically significant difference of relative ADC values between ≤T3 and T4 stages, and a cut-off of 0.64 s/mm2 could differentiate these stages with an odds ratio of 7.714 (95% confidence interval, 1.479-40.243). The area under the receiver operating characteristic curve for differentiating ≤T3 and T4 stages was 0.725.

CONCLUSION

DW-MRI may contribute to the clinical staging of non-metastatic GC. In particular, relative ADC of DW-MRI can distinguish T4 gastric cancer from less advanced T-stages.

Value of quantitative dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging in predicting extramural venous invasion in locally advanced gastric cancer and prognostic significance

Background

Extramural venous invasion (EMVI) has been found to be related to poor prognosis in gastric cancer. Preoperative diagnosis of EMVI is challenging, as it can only be detected by surgical pathology. The present study aimed to investigate the value of quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) in predicting EMVI preoperatively, and to determine the relationship between prediction results and prognosis in patients with locally advanced gastric cancer (LAGC).

Methods

Between January, 2015, and June, 2017, 79 LAGC patients underwent MRI preoperatively were enrolled in this study. Pathological EMVI (pEMVI) was used as the gold standard for diagnosis. The differences in quantitative DCE-MRI and DWI parameters between groups with different pEMVI status were analyzed. Multivariate logistic regression was used to build the combined prediction model for pEMVI with statistically significant quantitative parameters. The performance of the model for predicting pEMVI was evaluated using receiver operating characteristic (ROC) analysis. Patients were grouped based on MRI-predicted EMVI (mrEMVI). Kaplan-Meier analysis was used to investigate the relationship between mrEMVI and 2-year recurrence-free survival (RFS).

Results

Of the 79 LAGC patients who underwent MRI, 29 were pEMVI positive and 50 were pEMVI negative. Among the patients' clinical and pathological characteristics, only postoperative staging showed a significant difference between the 2 groups (P=0.015). The pEMVI-positive group had higher volume transfer constant (K^trans) and rate constant (k_ep), and lower apparent diffusion coefficient (ADC) values than the negative group (0.189 vs. 0.082 min^-1, 0.687 vs. 0.475 min^-1, and 1.230×10^-3 vs. 1.463×10^-3 mm²/s, respectively; P<0.05). Quantitative parameters, K^trans and k_ep, and ADC values, were independently associated with pEMVI which odds ratio values were 3.66, 2.65, and 0.30 (P<0.05), respectively, using multivariate logistic regression. ROC analysis showed that the area under the curve, sensitivity, specificity, positive predictive value, and negative predictive value in predicting pEMVI using combined K^trans, k_ep, and ADC values were 0.879, 72.4%, 96%, 91.3%, and 85.7%, respectively. A total of 23 cases were considered to be mrEMVI positive, and 56 cases were considered to be mrEMVI negative, according to the predictive results. The median RFS of the mrEMVI-positive group was significant lower than the negative group (21.7 vs. 31.2 months), and the 2-year RFS rate in the mrEMVI-positive group was significantly lower than that of the negative group (43.6% vs. 72.5%, P=0.010).

Conclusions

The quantitative DCE-MRI parameters, K^trans and k_ep, and DWI parameter, ADC, are independent predictors of pEMVI in LAGC; mrEMVI was confirmed to be a poor prognostic predictor for RFS.

The Role of Diffusion-weighted Imaging in Patients with Gastric Wall Thickening

BACKGROUND

Gastric cancer is the second leading cause of cancer death worldwide.

AIMS

In the benign and malign gastric pathologies, we measured the Apparent Diffusion Coefficient (ADC) value from the thickened section of the stomach wall. We assessed the diagnostic value of ADC and we wanted to see whether this value could be used to diagnose gastric pathologies.

STUDY DESIGN

This study has a prospective study design.

METHODS

A total of 90 patients, 27 with malign gastric pathologies 63 with benign gastric pathologies with Gastric Wall (GW) thickening in multidector CT, were evaluated by T2 weighted axial MR imaging and Diffusion-Weighted Imaging (DWI). Measurements were made both from the thickened wall and from the normal GW. Also, a new method called GW/spine ADC ratio was performed in image analysis. The value found after ADC measurement from the GW was proportioned to the spinal cord ADC value in the same section.

RESULTS

The ADC values measured from the pathological wall in patients with gastric malignancy (1.115 ± 0.156 x10-3 mm2/s) were significantly lower than the healthy wall measurements (1.621 ± 0.292 × 10-3 mm2/s) and benign gastric diseases (1.790± 0.359 x10-3 mm2/s). GW/spine ADC ratio was also lower in gastric malignancy group.

CONCLUSION

ADC measurement in DWI can be used to distinguish between benign and malign gastric pathologies.

Diffusion-Weighted Imaging in Oncology: An Update

To date, diffusion weighted imaging (DWI) is included in routine magnetic resonance imaging (MRI) protocols for several cancers. The real additive role of DWI lies in the "functional" information obtained by probing the free diffusivity of water molecules into intra and inter-cellular spaces that in tumors mainly depend on cellularity. Although DWI has not gained much space in some oncologic scenarios, this non-invasive tool is routinely used in clinical practice and still remains a hot research topic: it has been tested in almost all cancers to differentiate malignant from benign lesions, to distinguish different malignant histotypes or tumor grades, to predict and/or assess treatment responses, and to identify residual or recurrent tumors in follow-up examinations. In this review, we provide an up-to-date overview on the application of DWI in oncology.

The role of MRI in the diagnosis and treatment of gastric cancer

Gastric cancer is the fifth most common malignancies and the third leading cause of cancer-related death worldwide, with more than 40% of new cases occurring in China. With the advancement of treatment methods, the application of adjuvant therapy and targeted drugs, the prognosis of patients with gastric cancer has been significantly improved. In recent years, more and more studies have reported that magnetic resonance imaging (MRI) showed great value in the clinical application among patients with gastric cancer, including preoperative staging, treatment response evaluation, predicting prognosis and histopathological features, treatment guidance, and molecular imaging. The remarkable research progress of MRI in gastric cancer will provide new evaluation and treatment approaches for clinical diagnosis and treatment. This article aims to review the current status of the application and research progress of MRI in patients with gastric cancer.

Reduced field-of-view diffusion-weighted imaging (DWI) in patients with gastric cancer: Comparison with conventional DWI techniques at 3.0T: A preliminary study

To evaluate the qualitative image quality and quantitative apparent diffusion coefficient (ADC) value of reduced field-of view (rFOV) and full field-of-view (fFOV) diffusion-weighted imaging (DWI) sequences at 3.0 T in patients with gastric cancer.Fifty-three patients (37 males, 16 females; mean age, 63.3 ± 10.3 years) with 60 lesions with gastric cancer who underwent magnetic resonance (MR) scans, including both rFOV-DWI and fFOV-DWI, were retrospectively analyzed. Two observers subjectively evaluated image quality for both the fFOV-DWI and rFOV-DWI sequences regarding the anatomic details, distortion, lesion conspicuity, artifacts, and overall image quality. The mean ADC values of gastric cancer were calculated. The Wilcoxon test and paired samples t test were used. Interobserver agreement was assessed using kappa statistics.The mean scores based on the 2 observers demonstrated significant differences in image quality in terms of anatomic details, distortion, lesion conspicuity, artifacts and overall image quality at both b values between rFOV-DWI and fFOV-DWI (P < .05) in the whole gastric area. rFOV-DWI yielded significantly better scores in image quality at b = 800 seconds/mm (P < .05) in patients with esophagogastric junction cancers, but there were no significant differences in the gastric corpus and gastric antrum region. The mean tumor ADC values of rFOV-DWI were significantly lower than those of fFOV-DWI (1.237 ± 0.228 × 10-3 mm/second vs 1.683 ± 0.322 × 10-3 mm/second, P < .001).rFOV-DWI yielded significantly better image quality (anatomic details, distortion, lesion conspicuity, artifacts, overall image quality) and more accurate ADC measurements than fFOV-DWI did.

Diffusion-weighted MRI with ADC mapping for response prediction and assessment of oesophageal cancer: A systematic review

PURPOSE

The aim was to perform a systematic review on the value of diffusion-weighted MRI (DW-MRI) with apparent diffusion coefficient (ADC) mapping in the prediction and assessment of response to chemo- and/or radiotherapy in oesophageal cancer.

MATERIALS AND METHODS

A systematic search was performed on Pubmed, Embase, Medline and Cochrane databases. Studies that evaluated the ADC for response evaluation before, during or after chemo- and/or radiotherapy were included. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the quality of the included studies.

RESULTS

Fourteen studies, comprising 516 patients, in which the response to treatment in oesophageal cancer was evaluated on ADC maps were included. Acquisition parameter settings for DW-MRI and ROI placement varied substantially. The reference standard was RECIST or endoscopic assessment in eight non-surgery studies and histopathology after surgery in six studies. A high pre-treatment ADC significantly correlated with good response in three out of 12 studies; conversely, one study reported a significantly higher pre-treatment ADC in poor responders. In five out of eight studies good responders showed a significantly larger relative increase in ADC two weeks after the onset of treatment (range 23-59%) than poor responders (range 1.5-17%). After chemo- and/or radiotherapy ADC results varied considerably, amongst others due to large variation in the interval between completion of therapy and DW-MRI.

CONCLUSION

DW-MRI for response evaluation to chemo- and/or radiotherapy in oesophageal cancer shows variable methods and results. A large relative ADC increase after two weeks of treatment seems most predictive for good response.

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.

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.

Aggressive undifferentiated pleomorphic sarcoma of the stomach involving long-term survival: A case report and literature review

Primary gastric undifferentiated pleomorphic sarcoma (UPS) is a rare disease with insufficient long-term follow-up data. In the present study, a 70-year-old male complained of abdominal fullness and visited our hospital. Abdominal computed tomography revealed a large tumor in the upper part of the stomach, which was accompanied by smaller tumors in the small intestinal mesentery. An endoscopic ultrasound-guided fine-needle biopsy examination of the gastric tumor revealed features of pleomorphic sarcoma and high-grade spindle-shaped cells. Total gastrectomy was performed on the primary tumor, together with combined resection of the small intestine for the metastatic tumors. However, the tumor recurred in the mesentery of the sigmoid colon 6 months after the operation. A second operation was performed to resect the recurrent tumor. Since the second surgical procedure, the patient has remained free from recurrence for >7 years. Although the prognosis of abdominal UPS was considered to be poor, even after curative surgery, the present case experienced a long-term survival of gastric UPS after undergoing surgical resection alone.

Gastric cancer and imaging biomarkers: Part 1 - a critical review of DW-MRI and CE-MDCT findings

Abstract

The current standard of care for gastric cancer imaging includes heterogeneity in image acquisition techniques and qualitative image interpretation. In addition to qualitative assessment, several imaging techniques, including diffusion-weighted magnetic resonance imaging (DW-MRI), contrast-enhanced multidetector computed tomography (CE-MDCT), dynamic-contrast enhanced MRI and 18F-fluorodeoxyglucose positron emission tomography, can allow quantitative analysis. However, so far there is no consensus regarding the application of functional imaging in the management of gastric cancer. The aim of this article is to specifically review two promising biomarkers for gastric cancer with reasonable spatial resolution: the apparent diffusion coefficient (ADC) from DW-MRI and textural features from CE-MDCT. We searched MEDLINE/ PubMed for manuscripts published from inception to 6 February 2018. Initially, we searched for (gastric cancer OR gastric tumour) AND diffusion weighted magnetic resonance imaging. Then, we searched for (gastric cancer OR gastric tumour) AND texture analysis AND computed tomography. We collated the results from the studies related to this query. There is evidence that: (1) the ADC is a promising biomarker for the evaluation of the aggressiveness (T and N stage), treatment response and prognosis of gastric cancer; (2) textural features are related to the degree of differentiation, Lauren classification, treatment response and prognosis of gastric cancer. We conclude that these imaging biomarkers hold promise as effective additional tools in the diagnostic pathway of gastric cancer and may facilitate the multidisciplinary work between the radiologist and clinician, and across different institutions, to provide a greater biological understanding of gastric cancer.

Key Points

• Quantitative imaging is the extraction of quantifiable features from medical images for the assessment of normal or pathological conditions and represents a promising area for gastric cancer.

• Quantitative analysis from CE-MDCT and DW-MRI allows the extrapolation of multiple imaging biomarkers.

• ADC from DW-MRI and CE- MDCT-based texture features are non-invasive, quantitative imaging biomarkers that hold promise in the evaluation of the aggressiveness, treatment response and prognosis of gastric cancer.

Prognostic significance of low miR-144 expression in gastric cancer

BACKGROUND

An overwhelming amount of evidence has emerged suggesting that dysregulated microRNAs (miRNAs) play crucial roles in tumorigenesis.

OBJECTIVE

The study was to analyze tissue/serum miR-144 expression in gastric cancer and then evaluate their potential to predict the prognosis of gastric cancer.

METHODS

We examined miR-144 levels in tissues and peripheral blood samples from 96 gastric cancer patients using real-time PCR. Then the association between tissue/serum miR-144 levels and clinicopathological parameters was determined.

RESULTS

The expression levels of miR-144 were significantly down-regulated in the cancerous tissue and serum samples from gastric cancer patients. Serum miR-144 was able to differentiate the gastric cancer patients from healthy controls with high accuracy. In addition, tissue and serum miR-144 levels were both associated with clinical stage and lymph node metastasis. Moreover, patients with lower tissue or serum miR-144 suffered worse 5 year overall survival and disease free survival.

CONCLUSIONS

Taken together, our data support the potential clinical value of tissue and serum miR-144 as prognostic biomarkers in gastric cancer.

Preoperative prediction of sentinel lymph node metastasis in breast cancer based on radiomics of T2-weighted fat-suppression and diffusion-weighted MRI

OBJECTIVES

To predict sentinel lymph node (SLN) metastasis in breast cancer patients using radiomics based on T₂-weighted fat suppression (T₂-FS) and diffusion-weighted MRI (DWI).

METHODS

We enrolled 146 patients with histologically proven breast cancer. All underwent pretreatment T₂-FS and DWI MRI scan. In all, 10,962 texture and four non-texture features were extracted for each patient. The 0.623 + bootstrap method and the area under the curve (AUC) were used to select the features. We constructed ten logistic regression models (orders of 1-10) based on different combination of image features using stepwise forward method.

RESULTS

For T₂-FS, model 10 with ten features yielded the highest AUC of 0.847 in the training set and 0.770 in the validation set. For DWI, model 8 with eight features reached the highest AUC of 0.847 in the training set and 0.787 in the validation set. For joint T₂-FS and DWI, model 10 with ten features yielded an AUC of 0.863 in the training set and 0.805 in the validation set.

CONCLUSIONS

Full utilisation of breast cancer-specific textural features extracted from anatomical and functional MRI images improves the performance of radiomics in predicting SLN metastasis, providing a non-invasive approach in clinical practice.

KEY POINTS

• SLN biopsy to access breast cancer metastasis has multiple complications. • Radiomics uses features extracted from medical images to characterise intratumour heterogeneity. • We combined T ₂ -FS and DWI textural features to predict SLN metastasis non-invasively.

Comparison of DWI and 18F-FDG PET/CT for assessing preoperative N-staging in gastric cancer: evidence from a meta-analysis

The diagnostic values of diffusion weighted imaging (DWI) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for N-staging of gastric cancer (GC) were identified and compared. After a systematic search to identify relevant articles, meta-analysis was used to summarize the sensitivities, specificities, and areas under curves (AUCs) for DWI and PET/CT. To better understand the diagnostic utility of DWI and PET/CT for N-staging, the performance of multi-detector computed tomography (MDCT) was used as a reference. Fifteen studies were analyzed. The pooled sensitivity, specificity, and AUC with 95% confidence intervals of DWI were 0.79 (0.73–0.85), 0.69 (0.61–0.77), and 0.81 (0.77–0.84), respectively. For PET/CT, the corresponding values were 0.52 (0.39–0.64), 0.88 (0.61–0.97), and 0.66 (0.62–0.70), respectively. Comparison of the two techniques revealed DWI had higher sensitivity and AUC, but no difference in specificity. DWI exhibited higher sensitivity but lower specificity than MDCT, and ¹⁸F-FDG PET/CT had lower sensitivity and equivalent specificity. Overall, DWI performed better than ¹⁸F-FDG PET/CT for preoperative N-staging in GC. When the efficacy of MDCT was taken as a reference, DWI represented a complementary imaging technique, while ¹⁸F-FDG PET/CT had limited utility for preoperative N-staging.

Prognostic value of pretreatment diffusion-weighted magnetic resonance imaging for outcome prediction of colorectal cancer liver metastases undergoing 90Y-microsphere radioembolization

PURPOSE

To investigate the clinical potential of pretreatment apparent diffusion coefficient (ADC) on diffusion-weighted magnetic resonance imaging (DWI) for therapy response and outcome prediction in patients with liver-predominant metastatic colorectal cancer (CRC) undergoing radioembolization with ⁹⁰Yttrium-microspheres (90Y-RE).

METHODS

Forty-six consecutive patients with unresectable CRC liver metastases underwent standardized clinical DWI on a 1.5 T MR scanner prior to and 4-6 weeks after 90Y-RE. Pretreatment clinical parameters, ADC values derived from region-of-interest analysis, and the corresponding tumor sizes of three treated liver metastases per subject were recorded. Long-term tumor response to radioembolization was categorized into response (partial remission) and nonresponse (stable disease, progressive disease) according to Response Evaluation Criteria in Solid Tumors v1.1 (RECIST) 3 months after treatment. Associations between long-term tumor response and the clinical and imaging parameters were evaluated. The impact of pretreatment clinical and imaging parameters on progression-free survival (PFS) and overall survival (OS) was further assessed by Kaplan-Meier and multivariate Cox-regression analyses.

RESULTS

Nonresponders had higher hepatic tumor burden (p = 0.021) and lower ADC values than patients responding to 90Y-RE, both pretreatment (986 ± 215 vs. 1162 ± 178; p = 0.036) and posttreatment (1180 ± 350 vs. 1598 ± 225; p = 0.002). ADC values higher than 935 × 10^-6 mm² (5 vs. 3 months; p = 0.022) and hepatic tumor burden ≤25% (6 vs. 3 months; p = 0.014) were associated with longer median PFS, whereas ADC >935 × 10^-6 mm² (14 vs. 6 months; p = 0.02), hepatic tumor burden ≤25% (14 vs. 6 months; p = 0.048), size of the largest metastasis <4.7 cm (18 vs. 7 months; p = 0.024), and Eastern Cooperative Oncology Group (ECOG) score <1 (8 vs. 5 months; p = 0.045) were associated with longer median OS. On multivariate analysis, ADC >935 × 10^-6 mm² and hepatic tumor burden ≤25% remained prognostic factors for PFS, and ADC >935 × 10^-6 mm² and size of the largest metastasis <4.7 cm were independent predictors of OS.

CONCLUSION

Pretreatment ADC on DWI represents a valuable prognostic biomarker for predicting both the therapeutic efficacy and survival prognosis in CRC liver metastases treated by 90Y-RE, allowing risk stratification and potentially optimizing further treatment strategies.

Apparent diffusion coefficient by diffusion-weighted magnetic resonance imaging as a sole biomarker for staging and prognosis of gastric cancer

Objective

To investigate the role of apparent diffusion coefficient (ADC) from diffusion-weighted magnetic resonance imaging (DW-MRI) when applied to the 7th TNM classification in the staging and prognosis of gastric cancer (GC).

Methods

Between October 2009 and May 2014, a total of 89 patients with non-metastatic, biopsy proven GC underwent 1.5T DW-MRI, and then treated with radical surgery. Tumor ADC was measured retrospectively and compared with final histology following the 7th TNM staging (local invasion, nodal involvement and according to the different groups — stage I, II and III). Kaplan-Meier curves were also generated. The follow-up period is updated to May 2016.

Results

Median follow-up period was 33 months and 45/89 (51%) deaths from GC were observed. ADC was significantly different both for local invasion and nodal involvement (P<0.001). Considering final histology as the reference standard, a preoperative ADC cut-off of 1.80×10^–3 mm²/s could distinguish between stages I and II and an ADC value of ≤1.36×10^–3 mm²/s was associated with stage III (P<0.001). Kaplan-Meier curves demonstrated that the survival rates for the three prognostic groups were significantly different according to final histology and ADC cut-offs (P<0.001).

Conclusions

ADC is different according to local invasion, nodal involvement and the 7th TNM stage groups for GC, representing a potential, additional prognostic biomarker. The addition of DW-MRI could aid in the staging and risk stratification of GC.

Apparent diffusion coefficient values detected by diffusion-weighted imaging in the prognosis of patients with locally advanced esophageal squamous cell carcinoma receiving chemoradiation

Purpose

Previous studies have demonstrated that apparent diffusion coefficient (ADC) values measured by magnetic resonance imaging have prognostic value in patients with esophageal squamous cell carcinoma (ESCC). However, the role of ADC needs to be validated in a cohort of Chinese ESCC patients. This study assessed the role of ADC in predicting the outcome of patients with ESCC treated only by chemoradiation in the People’s Republic of China.

Patients and methods

Seventy-three patients with local advanced ESCC were retrospectively analyzed in this study; none of the patients underwent surgery before or after chemoradiation. The ADC values of the primary tumors were determined by magnetic resonance imaging. The ADC values were then correlated with clinicopathological and other radiological parameters. Survival analysis was carried out to determine if ADC had an impact on survival of these patients.

Results

The median ADC value of the esophageal cancer tissue was 1.256*10⁻³ mm²/sec (range: 0.657–2.354*10⁻³ mm²/sec, interquartile range 0.606*10⁻³ mm²/sec). No clinicopathological or radiological parameters were associated with the ADC values except the sites of tumor tissues. ADC <1.076*10⁻³ mm²/sec predicted significantly worse survival in patients with ESCC (12.9 months vs undefined, P=0.0108).

Conclusion

The ADC value is a potent prognostic factor which can be used to predict the outcome of patients with ESCC treated only by chemoradiation.

Complementary value of pre-treatment apparent diffusion coefficient in rectal cancer for predicting tumor recurrence

PURPOSE

To assess the complementary prognostic value of pre-treatment tumor apparent diffusion coefficient (ADC) for the prediction of tumor recurrence in patients with rectal cancer.

METHODS

From March 2012 to March 2013, a total of 128 patients with mid/lower rectal cancer who underwent pre-treatment rectal MRI were enrolled in this retrospective study. Two radiologists in consensus evaluated conventional imaging features (Cimg) in pre-treatment rectal MRI: tumor height from anal verge (≤5 cm vs. >5 cm), T stage (high vs. low), the presence or absence of lymph node metastasis, mesorectal fascia invasion, and extramural venous invasion. The mean tumor ADC values (TumorADC) based on high b-value (0, 1000 × 10(-3) mm(2)/s) diffusion weight images were extracted. A multivariate Cox proportional hazard (CPH) regression was performed to evaluate the association of Cimg and TumorADC with the 3-year local recurrence (LR) rate. Predictive performance of two multivariate CPH models (Cimg only vs. Cimg + TumorADC) was compared using Harrell's c index (HCI).

RESULTS

TumorADC (Adjusted HR, 7.830; 95% CI 3.937-15.571) and high T stage (Adjusted HR, 8.039; 95% CI 2.405-26.874) were independently associated with the 3-year LR rate. The CPH model generated with T stage + TumorADC (HCI, 0.820; 95% CI 0.708-0.932) showed significantly higher HCI than that with T stage only (HCI, 0.742; 95% CI 0.594-0.889) (P = 0.009).

CONCLUSIONS

In patients with mid/lower rectal cancer, integrating TumorADC to Cimg increases predictive performance of the CPH model than that with Cimg alone for the prediction of LR within 3 years after surgery.

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.

DWI as a Quantitative Biomarker in Predicting Chemotherapeutic Efficacy at Multitime Points on Gastric Cancer Lymph Nodes Metastases

The purpose of the hypothesis testing is to determine that apparent diffusion coefficient (ADC) as an early biomarker can predict the metastatic lymph nodes' (LNs) response to neoadjuvant chemotherapy in advanced gastric cancer (GC) in early stage. From March 2011 to June 2015, 106 patients with advanced GC were enrolled in the study. Patients underwent conventional magnetic resonance imaging and functional diffusion weighted imaging before and 3 days, 7 days, 30 days, and 60 days following the standard chemotherapy. After surgery, among 3034 detected LNs, the positive group was divided into complete response (CR) group, partial response (PR) group, and stable disease (SD) group in accordance to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Mean ADCs, short/long diameters of LNs before chemotherapy between the whole positive and the negative LNs were compared by t test. Changes of mean ADCs in 3 groups were analyzed by 1-way ANOVA. The mean ADC of the whole positive LNs was (1.145 ± 0.014) × 10⁻³ mm²/s, which was significantly lower than that of the whole negative LNs ([1.491 ± 0.010] × 10⁻³ mm²/s; P < 0.05). The means of both short/long diameters in the whole positive LNs were significantly longer than those in the whole negative LNs (P < 0.05). In CR, PR, and SD groups, the mean ADC of metastatic LNs on the 3rd day, 7th day, 13th day, and 16th day following the chemotherapy were all higher than that of LNs before chemotherapy, respectively (all P < 0.05). In addition, significant difference was found between mean ADCs in any 2 time points (all P < 0.05), except between mean ADCs in the 3rd day and in the 7th day of the chemotherapy. In conclusion, ADC can be used as an early biomarker to predict the metastatic LNs' response to neoadjuvant chemotherapy in advanced GC in early stage.

Prognostic utility of diffusion-weighted MRI in oesophageal cancer: is apparent diffusion coefficient a potential marker of tumour aggressiveness?

PURPOSE

To investigate the role of the apparent diffusion coefficient (ADC) as a potential prognostic biomarker in the evaluation of the aggressiveness of oesophageal cancer.

MATERIALS AND METHODS

Between November 2009 and December 2013, 43 patients with evidence of oesophageal or oesophago-gastric junction cancer were referred to our institution and prospectively entered in our database. The final study population consisted of 23 patients (18 men; 5 women; mean age, 64.62 ± 10.91 years) who underwent diffusion-weighted Magnetic Resonance before surgical intervention. Specifically, 14 were directly treated with surgery and 9 were addressed to chemo/radiotherapy beforehand. Two radiologists independently measured mean tumour ADC and inter-observer agreement (Spearman's and intraclass correlation coefficient [ICC]) was assessed. In the univariate analysis, overall survival curves related to pathological ADC, pT, pN, tumour location and histotype were fitted using the Kaplan-Meier method. Survival curves were then compared using the log-rank test.

RESULTS

Inter-observer reproducibility was very good (Spearman's rho = 0.95; ICC = 0.94). At a total median follow-up of 19 months (2-49 months), 4 patients had died. The median follow-up was 18.50 months (5-49 months) for the surgery-only group (1/4 events, 25 %) and 24 months (2-34 months) for the chemo/radiotherapy group (3/4 events, 75 %). Survival time at 48 months for the overall population was 59 % (±0.11), while for the surgery-only group and the chemo/radiotherapy group was 90 % (±0.09) and 61 % (±0.34), respectively. In the univariate analysis, ADC values below or equal to 1.4 × 10(-3) mm(2)/s were associated with a negative prognosis both in the total population (P = 0.016) and in the surgery-only group (P < 0.001).

CONCLUSION

Despite the biggest limitation of our study (i.e. the small study population), we were able to show that pathological ADC could be considered a prognostic factor for oesophageal cancer. DWI might be introduced into clinical practice as a promising and reliable technique in the diagnostic pathway of this tumour.