The Relationship Between MR Demonstration of Extramural Venous Invasion and Nodal Disease in Rectal Cancer

Study on the diagnostic value of MDCT extramural vascular invasion in preoperative N staging of gastric cancer patients

BACKGROUND

To explore the diagnostic value of multidetector computed tomography (MDCT) extramural vascular invasion (EMVI) in preoperative N Staging of gastric cancer patients.

METHODS

According to the MR-defined EMVI scoring standard of rectal cancer, we developed a 5-point scale scoring system to evaluate the status of CT-detected extramural vascular invasion(ctEMVI), 0-2 points were ctEMVI-negative status, and 3-4 points were positive status for ctEMVI. Patients were divided into ctEMVI positive group and ctEMVI negative group. The correlation between ctEMVI and clinical features was analyzed. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of ctEMVI for pathological metastatic lymph nodes and N staging, The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of pathological N staging using ctEMVI and short-axis diameter were generated and compared.

RESULTS

The occurrence rate of lymphovascular invasion (LVI) and proportion of tumors with a greatest diameter > 6 cm in the ctEMVI positive group was higher than that in the ctEMVI negative group (P < 0.05). Spearman correlation analysis showed a positive correlation between ctEMVI and LVI, N stage, and tumor size (P < 0.05). For ctEMVI scores ≥ 3,The AUC of ctEMVI for diagnosing lymph node metastasis, N stage ≥ N2, and N3 stage were 0.857, 0.802, and 0.758, respectively. The sensitivity, NPV and accuracy of ctEMVI for diagnosing N stage ≥ N2 were superior to those of short-axis diameter (P < 0.05), while sensitivity, specificity, PPV, NPV, and accuracy of ctEMVI for diagnosing N3 stage were superior to those of short-axis diameter (P < 0.05).

CONCLUSION

ctEMVI has important value in diagnosing metastatic lymph nodes and advanced N staging. As an important imaging marker, ctEMVI can be included in the preoperative imaging evaluation of patients, providing important assistance for clinical guidance and treatment.

Predictive value of lesion morphology in rectal cancer based on MRI before surgery

OBJECTIVE

To explore the relationship of MRI morphology of primary rectal cancer with extramural vascular invasion (EMVI), metastasis and local recurrence.

MATERIALS AND METHODS

This retrospective study included 153 patients with rectal cancer. Imaging factors and histopathological index including nodular projection (NP), cord sign (CS) at primary tumor margin, irregular nodules (IN) of mesorectum, MRI-detected peritoneal reflection invasion (PRI), range of rectal wall invasion (RRWI), patterns and length of tumor growth, maximal extramural depth (EMD), histologically confirmed local node involvement (hLN), MRI T stage, MRI N stage, MRI-detected extramural vascular invasion (mEMVI) and histologically confirmed extramural vascular invasion (hEMVI) were evaluated. Determining the relationship between imaging factors and hEMVI, synchronous metastasis and local recurrence by univariate analysis and multivariable logistic regression, and a nomogram validated internally via Bootstrap self-sampling was constructed based on the latter.

RESULTS

Thirty-eight cases of hEMVI, fourteen cases of synchronous metastasis and ten cases of local recurrence were observed among 52 NP cases. There were 50 cases of mEMVI with moderate consistency with hEMVI (Kappa = 0.614). NP, CS, EMD and mEMVI showed statistically significant differences in the negative and positive groups of hEMVI, synchronous metastasis, and local recurrence. Compared to patients with local mass growth, the rectal tumor with circular infiltration had been found to be at higher risk of synchronous metastasis and local recurrence (P < 0.05). NP and IN remained as significant predictors for hEMVI, and mEMVI was a predictor for synchronous metastasis, while PRI and mEMVI were predictors for local recurrences. The nomogram for predicting hEMVI demonstrated a C-index of 0.868, sensitivity of 86.0%, specificity of 79.6%, and accuracy of 81.7%.

CONCLUSION

NP, CS, IN, large EMD, mEMVI, and circular infiltration are significantly associated with several adverse prognostic indicators. The nomogram based on NP has good predictive performance for preoperative EMVI. mEMVI is a risk factor for synchronous metastasis. PRI and mEMVI are risk factors for local recurrence.

MRI Assessment of Extramural Venous Invasion Before and After Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer and Its Association with Disease-Free and Overall Survival

BACKGROUND

Extramural venous invasion (EMVI) on baseline MRI is associated with poor prognosis in patients with locally advanced rectal cancer. This study investigated the association of persistent EMVI after total neoadjuvant therapy (TNT) (chemoradiotherapy and systemic chemotherapy) with survival.

METHODS

Baseline MRI, post-TNT MRI, and surgical pathology data from 175 patients with locally advanced rectal cancer who underwent TNT and total mesorectal excision between 2010 and 2017 were retrospectively analyzed for evidence of EMVI. Two radiologists assessed EMVI status with disagreement adjudicated by a third. Pathologic EMVI status was assessed per departmental standards. Cox regression models evaluated the associations between EMVI and disease-free and overall survival.

RESULTS

EMVI regression on both post-TNT MRI and surgical pathology was associated with disease-free survival (hazard ratio, 0.17; 95% confidence interval (CI), 0.04-0.64) and overall survival (hazard ratio, 0.11; 95% CI, 0.02-0.68). In an exploratory analysis of 35 patients with EMVI on baseline MRI, only six had EMVI on pathology compared with 18 on post-TNT MRI; these findings were not associated (p = 0.2). Longer disease-free survival was seen with regression on both modalities compared with remaining positive. Regression on pathology alone, independent of MRI EMVI status, was associated with similar improvements in survival.

CONCLUSIONS

Baseline EMVI is associated with poor prognosis even after TNT. EMVI regression on surgical pathology is common even with persistent EMVI on post-TNT MRI. EMVI regression on surgical pathology is associated with improved DFS, while the utility of post-TNT MRI EMVI persistence for decision-making and prognosis remains unclear.

Histogram analysis of dynamic contrast-enhanced magnetic resonance imaging to predict extramural venous invasion in rectal cancer

BACKGROUND

To explore the potential of histogram analysis (HA) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the identification of extramural venous invasion (EMVI) in rectal cancer patients.

METHODS

This retrospective study included preoperative images of 194 rectal cancer patients at our hospital between May 2019 and April 2022. The postoperative histopathological examination served as the reference standard. The mean values of DCE-MRI quantitative perfusion parameters (Ktrans, Kep and Ve) and other HA features calculated from these parameters were compared between the pathological EMVI-positive and EMVI-negative groups. Multivariate logistic regression analysis was performed to establish the prediction model for pathological EMVI-positive status. Diagnostic performance was assessed and compared using the receiver operating characteristic (ROC) curve. The clinical usefulness of the best prediction model was further measured with patients with indeterminate MRI-defined EMVI (mrEMVI) score 2(possibly negative) and score 3 (probably positive).

RESULTS

The mean values of Ktrans and Ve in the EMVI-positive group were significantly higher than those in the EMVI-negative group (P = 0.013 and 0.025, respectively). Significant differences in Ktrans skewness, Ktrans entropy, Ktrans kurtosis, and Ve maximum were observed between the two groups (P = 0.001,0.002, 0.000, and 0.033, respectively). The Ktrans kurtosis and Ktrans entropy were identified as independent predictors for pathological EMVI. The combined prediction model had the highest area under the curve (AUC) at 0.926 for predicting pathological EMVI status and further reached the AUC of 0.867 in subpopulations with indeterminate mrEMVI scores.

CONCLUSIONS

Histogram Analysis of DCE-MRI Ktrans maps may be useful in preoperative identification of EMVI in rectal cancer, particularly in patients with indeterminate mrEMVI scores.

Extramural vascular invasion as an independent prognostic marker in locally advanced rectal cancer: propensity score match pair analysis

BACKGROUND

In rectal cancers, presence of extramural vascular invasion on MRI (mrEMVI) is associated with poor survival. The independent influence of mrEMVI in the presence of other prognostic factors has not been previously analyzed using match pair analysis.

PATIENTS AND METHODS

Consecutive 92 patients having mrEMVI at presentation treated between January 2016 and December 2018 were matched with 92 patients (1:1) without mrEMVI. Matching parameters were T stage, mesorectal fascia involvement, and tumor differentiation. The presence and absence of mrEMVI were correlated to outcomes. An event was defined as locoregional failure or distant metastasis or poor response to chemoradiation rendering the rectal tumor as inoperable.

RESULTS

At 3 years, in the mrEMVI-positive cohort, 59% had an event and in the mrEMVI-negative cohort, 45% had an event (p = 0.026). Local control was 90.2% (12recurrences in 122 who underwent surgery), two recurrences in the mrEMVI-positive cohort and ten patients in the mrEMVI-negative cohort, which missed statistical significance (p = 0.06). Distant metastasis-free survival was significantly worse in the mrEMVI-positive cohort versus the mrEMVI-negative cohort (58.2% vs. 69.4%) (p = 0.022). Similarly, Overall survival was significantly inferior in mrEMVI-positive cohort compared to the mrEMVI-negative cohort (57% vs. 72.4%) (p = 0.02). The multivariate regression analysis confirmed the independent predictive value of mrEMVI.  CONCLUSION: Extramural vascular invasion detected through MRI is an independent risk factor for distant metastasis in the locally advanced carcinoma rectum. Aggressive treatment regimens like total neoadjuvant treatment should be considered in these cases pending randomized control studies.

Extramural venous invasion (EMVI) revisited: a detailed analysis of various characteristics of EMVI and their role as a predictive imaging biomarker in the neoadjuvant treatment response in rectal cancer

PURPOSE

To assess whether size, diameter, and large vein involvement of MR-detected extramural venous invasion (MR-EMVI) have an impact on neoadjuvant therapy response in rectal adenocarcinoma.

METHODS

57 patients with locally advanced rectal adenocarcinoma scanned with MRI before and after neoadjuvant therapy were included. Two abdominal radiologists evaluated the images with special emphasis on EMVI, on initial staging and after neoadjuvant treatment. The sensitivity and specificity of MRI for detection of rest EMVI were determined. The association of various MR-EMVI characteristics including number, size, and main vein involvement with treatment response was investigated. In subjects with discordance of radiology and pathology, elastin stain was performed, and images and slides were re-evaluated on site with a multidisciplinary approach.

RESULTS

At initial evaluation, 17 patients were MR-EMVI negative (29.8%) and 40 were MR-EMVI positive (70.2%). Complete/near-complete responders had less number (mean 1.45) and smaller diameter of MR-EMVI (mean 1.8 mm), when compared with partial responders (2.54 and 3.3 mm; p < 0.005). The sensitivity of MRI for rest EMVI detection was high, specificity was moderate, and in one patient elastin stain changed the final decision. In five patients with rest MR-EMVI positivity, carcinoma histopathologically had a distinctive serpiginous perivascular spread, growing along the track of vascular bundle, although it did not appear in intravascular spaces.

CONCLUSION

This study demonstrates that not only the presence, but also size and number of EMVI that may be significant clinically and thus these parameters also ought to be incorporated to the MRI evaluation and prognostication of treatment response. From pathology perspective, tumors growing alongside major vessels may also reflect EMVI even if they are not demonstrably "intravascular."

MRI Evaluation of Extramural Venous Invasion (EMVI) with Rectal Carcinoma Using High Resolution T2 and Combination of High Resolution T2 and Contrast Enhanced T1 Weighted Imaging

Background:

EMVI is a direct invasion of a vein by a tumor. As a predictor of hematogenous metastasis, it is a poor prognostic factor in rectal cancer and can be accurately identified on MRI prior to surgical procedure.

Objective:

To evaluate the role of contrast-enhanced T1-weighted magnetic resonance imaging (CET1WI) in addition to high-resolution T2-weighted imaging (HRT2WI) in assessing extramural venous invasion (EMVI) of rectal cancer.

Methods:

In all 195 patients with rectal cancer, HRT2WI and CET1WI sequences were produced within pre-operative MRI for the purpose of assessing for the presence of EMVI (mrEMVI). CET1WI sequences were produced following administration of Gadolinium contrast medium. mrEMVI assessment results were classified into two groups. Group A consisted of mrEMVI assessment results obtained using HRT2WI sequences only. Group B consisted of mrEMVI assessment results obtained using a combination of HRT2WI + CET1WI sequences. Results obtained for each group (A and B) were correlated with a histopathological finding (pEMVI) as a reference standard.

Results:

Out of a total of 195 rectal cancer patients, mrEMVI was positive in 41 (21%) patients in group A, and in 45 (23%) patients in group B. Histopathological finding demonstrated pEMVI in 54 (27.7%) patients. A statistical analysis of group A (HRT2WI sequences) resulted in 75.9% sensitivity to mrEMVI and 96.4% specificity, Positive Predictive Value of 89.1% and Negative Predictive Value of 91.2% (95% confidence interval (CI), p< 0.05). Statistical analysis of group B (HRT2WI + CET1WI sequences) resulted in 83.3% sensitivity to mrEMVI and 98.5% specificity, Positive Predictive Value of 89.1% and Negative Predictive Value of 91.2% (CI 95%, p< 0.05).

Conclusion:

T1-weighted magnetic resonance imaging (CET1WI) in addition to high-resolution T2-weighted imaging (HRT2WI) increased evaluation of extramural venous invasion (EMVI) of rectal cancer.

MRI-detected extramural venous invasion of rectal cancer: Multimodality performance and implications at baseline imaging and after neoadjuvant therapy

MRI is routinely used for rectal cancer staging to evaluate tumor extent and to inform decision-making regarding surgical planning and the need for neoadjuvant and adjuvant therapy. Extramural venous invasion (EMVI), which is intravenous tumor extension beyond the rectal wall on histopathology, is a predictor for worse prognosis. T2-weighted images (T2WI) demonstrate EMVI as a nodular-, bead-, or worm-shaped structure of intermediate T2 signal with irregular margins that arises from the primary tumor. Correlative diffusion-weighted images demonstrate intermediate to high signal corresponding to EMVI, and contrast enhanced T1-weighted images demonstrate tumor signal intensity in or around vessels. Diffusion-weighted and post contrast images may increase diagnostic performance but decrease inter-observer agreement. CT may also demonstrate obvious EMVI and is potentially useful in patients with a contraindication for MRI. This article aims to review the spectrum of imaging findings of EMVI of rectal cancer on MRI and CT, to summarize the diagnostic accuracy and inter-observer agreement of imaging modalities for its presence, to review other rectal neoplasms that may cause EMVI, and to discuss the clinical significance and role of MRI-detected EMVI in staging and restaging clinical scenarios.

Association between high-resolution MRI-detected extramural vascular invasion and tumour microcirculation estimated by dynamic contrast-enhanced MRI in rectal cancer: preliminary results

Background

To determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) status is associated with quantitative perfusion parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) in rectal cancer.

Methods

Seventy-two patients with rectal adenocarcinoma who underwent curative surgery alone within 2 weeks following rectal MRI were enrolled in this retrospective study. mrEMVI status was determined based on high-resolution MRI. The quantitative perfusion parameters (K^trans, k_ep and v_e) derived from DCE-MRI were calculated from all sections containing tumours. DCE-MRI parameters and clinicopathological variables in patients with different mrEMVI statuses were compared.

Results

For patients who were mrEMVI positive, the tumours demonstrated significantly lower k_ep values (P = 0.012) and higher v_e values (P = 0.021) than tumours of patients who were mrEMVI negative, while the K^trans value displayed no significant difference (P = 0.390). The patients who were mrEMVI positive had larger tumour size, higher pathological tumour stage and increased regional nodal metastases compared to those who were mrEMVI negative (2.9 cm vs. 3.5 cm, P = 0.011; 63.8% vs. 92.0%, P = 0.010; 36.2% vs. 76.0%, P = 0.001; respectively).

Conclusions

This study demonstrated for the first time that tumour microcirculation is altered in mrEMVI-positive patients with rectal adenocarcinoma, as evidenced by significantly lower k_ep and higher v_e values. In addition, these patients were more likely to have a larger tumour size, a higher pathological tumour stage and regional nodal metastases than mrEMVI-negative patients.

How Should Imaging Direct/Orient Management of Rectal Cancer?

Modern rectal cancer management is dependent on preoperative staging, and radiological assessment is a crucial part of this process. Imaging must provide sufficient information to guide preoperative decision-making that is reliable and reproducible. Different methods have been used for local staging; however, magnetic resonance imaging (MRI) has shown to be the most reliable tool for this purpose. MRI offers prognostic information about the patients and guides the decision between neoadjuvant treatment and total mesorectal excision alone. Also, not only the initial staging but also restaging by MRI can provide significant information regarding tumor response that is essential when considering alternative approaches.

[Local imaging of rectal cancer--update 2015: MRI as imaging biomarker]

The significance of state of the art magnetic resonance imaging (MRI) for rectal cancer goes far beyond the detection and diagnostics of local dispersion and is increasingly focusing on patient prognosis. The identification of prognostic factors, such as tumor (T) and nodal (N) status, involvement of the circumferential resection margin, presence of extramural vascular invasion, tumor response prediction following neoadjuvant therapy, therapy-related changes in microcirculation, permeability and tissue cellularity and structured reporting are important elements of advanced rectal cancer imaging. In this context, multiparametric MRI is progressively evolving into a powerful imaging biomarker.

Imaging in rectal cancer with emphasis on local staging with MRI

Imaging in rectal cancer has a vital role in staging disease, and in selecting and optimizing treatment planning. High-resolution MRI (HR-MRI) is the recommended method of first choice for local staging of rectal cancer for both primary staging and for restaging after preoperative chemoradiation (CT-RT). HR-MRI helps decide between upfront surgery and preoperative CT-RT. It provides high accuracy for prediction of circumferential resection margin at surgery, T category, and nodal status in that order. MRI also helps assess resectability after preoperative CT-RT and decide between sphincter saving or more radical surgery. Accurate technique is crucial for obtaining high-resolution images in the appropriate planes for correct staging. The phased array external coil has replaced the endorectal coil that is no longer recommended. Non-fat suppressed 2D T2-weighted (T2W) sequences in orthogonal planes to the tumor are sufficient for primary staging. Contrast-enhanced MRI is considered inappropriate for both primary staging and restaging. Diffusion-weighted sequence may be of value in restaging. Multidetector CT cannot replace MRI in local staging, but has an important role for evaluating distant metastases. Positron emission tomography-computed tomography (PET/CT) has a limited role in the initial staging of rectal cancer and is reserved for cases with resectable metastatic disease before contemplating surgery. This article briefly reviews the comprehensive role of imaging in rectal cancer, describes the role of MRI in local staging in detail, discusses the optimal MRI technique, and provides a synoptic report for both primary staging and restaging after CT-RT in routine practice.

Pathologic processing of the total mesorectal excision

Total mesorectal excision (TME) is the current optimal surgical treatment for patients with rectal carcinoma. A complete TME is related to lower local recurrence rates and increased patient survival. Many confounding factors in the patient's anatomy and prior therapy can make it difficult to obtain a perfect plane, and thus a complete TME. The resection specimen can be thoroughly evaluated, grossly and microscopically, to identify substandard surgical outcomes and increased risk of local recurrence. Complete and accurate data reporting is critical for patient care and helps surgeons improve their technique.

MRI-detected extramural vascular invasion is an independent prognostic factor for synchronous metastasis in patients with rectal cancer

OBJECTIVES

To determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (EMVI) could predict synchronous distant metastases in rectal cancer.

METHODS

Patients who underwent rectal MRI between July 2011 and December 2012 were screened. This study included 447 patients with pathologically confirmed rectal adenocarcinoma who had undergone MRI without previous treatment. Distant metastases were recorded at the initial work-up and over a 6-month follow-up. Univariate/multivariate logistic regression models were used to determine the risk of metastasis. The diagnostic performance was calculated using pathologic lymphovascular invasion (LVI) as a gold standard.

RESULTS

Among 447 patients, 79 patients (17.7 %) were confirmed to have distant metastases. Three MRI features are significantly associated with a high risk of distant metastasis: positive EMVI (odds ratio 3.02), high T stage (odds ratio 2.10) and positive regional lymph node metastasis (odds ratio 6.01). EMVI in a large vessel (≥3 mm) had a higher risk for metastasis than EMVI in a small vessel (<3 mm). Sensitivity, specificity and accuracy of MRI-detected EMVI were 28.2 %, 94.0 % and 80.3 %, respectively.

CONCLUSIONS

MRI-detected EMVI is an independent risk factor for synchronous metastasis in rectal cancer. EMVI in large vessels is a stronger risk factor for distant metastasis than EMVI in small vessels.

KEY POINTS

• EMVI, LN metastasis and T staging on MRI are risk factors for metastasis. • EMVI in large vessels has greater risk for metastasis than in small vessels. • Regional LN metastasis on MRI has highest risk for predicting metastasis. • MR findings could be helpful for selecting patients at high risk for metastasis.

The role of perfusion effects in monitoring of chemoradiotherapy of rectal carcinoma using diffusion-weighted imaging

PURPOSE

The aim of this study was to characterize and understand the therapy-induced changes in diffusion parameters in rectal carcinoma under chemoradiotherapy (CRT). The current literature shows conflicting results in this regard. We applied the intravoxel incoherent motion model, which allows for the differentiation between diffusion (D) and perfusion (f) effects, to further elucidate potential underlying causes for these divergent reports.

MATERIALS AND METHODS

Eighteen patients with primary rectal carcinoma undergoing preoperative CRT were examined before, during, and after neoadjuvant CRT using diffusion-weighted imaging. Using the intravoxel incoherent motion approach, f and D were extracted and compared with postoperative tumor downstaging and volume.

RESULTS

Initial diffusion-derived parameters were within a narrow range (D1 = 0.94 ± 0.12 × 10(-3) mm(2)/s). At follow-up, D rose significantly (D2 = 1.18 ± 0.13 × 10(-3) mm(2)/s; P < 0.0001) and continued to increase significantly after CRT (D3 = 1.24 ± 0.14 × 10(-3) mm(2)/s; P < 0.0001). The perfusion fraction f did not change significantly (f1 = 9.4 ± 2.0%, f2 = 9.4 ± 1.7%, f3 = 9.5 ± 2.7%). Mean volume (V) decreased significantly (V1 = 16,992 ± 13,083 mm(3); V2 = 12,793 ± 8317 mm(3), V3 = 9718 ± 6154 mm(3)). T-downstaging (10:18 patients) showed no significant correlation with diffusion-derived parameters.

CONCLUSIONS

Conflicting results in the literature considering apparent diffusion coefficient (ADC) changes in rectal carcinoma under CRT for patients showing T-downstaging are unlikely to be due to perfusion effects. Our data support the view that under effective therapy, an increase in D/ADC can be observed.

Magnetic resonance imaging for the clinical management of rectal cancer patients: recommendations from the 2012 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting

OBJECTIVES

To develop guidelines describing a standardised approach regarding the acquisition, interpretation and reporting of magnetic resonance imaging (MRI) for clinical staging and restaging of rectal cancer.

METHODS

A consensus meeting of 14 abdominal imaging experts from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) was conducted following the RAND-UCLA Appropriateness Method. Two independent (non-voting) chairs facilitated the meeting. Two hundred and thirty-six items were scored by participants for appropriateness and classified subsequently as appropriate or inappropriate (defined by ≥ 80 % consensus) or uncertain (defined by < 80 % consensus). Items not reaching 80 % consensus were noted.

RESULTS

Consensus was reached for 88 % of items: recommendations regarding hardware, patient preparation, imaging sequences, angulation, criteria for MRI assessment and MRI reporting were constructed from these.

CONCLUSIONS

These expert consensus recommendations can be used as clinical guidelines for primary staging and restaging of rectal cancer using MRI.

KEY POINTS

• These guidelines recommend standardised imaging for staging and restaging of rectal cancer. • The guidelines were constructed through consensus amongst 14 abdominal imaging experts. • Consensus was reached by in 88 % of 236 items discussed.