Assessment of tumor microcirculation with dynamic contrast-enhanced MRI in patients with esophageal cancer: initial experience

Diagnostic Performance of Vascular Permeability and Texture Parameters for Evaluating the Response to Neoadjuvant Chemoradiotherapy in Patients With Esophageal Squamous Cell Carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is an aggressive type of cancer, associated with poor prognosis. The development of an accurate and non-invasive method to evaluate the pathologic response of patients with ESCC to chemoradiotherapy remains a critical issue. Therefore, the aim of this study was to assess the importance of vascular permeability and texture parameters in predicting the response to neoadjuvant chemoradiotherapy (NACRT) in patients with ESCC.

Methods

This prospective analysis included patients with T1–T2 stage of ESCC, without either lymphatic or metastasis, and distant metastasis. All patients underwent surgery having received two rounds of NACRT. All patients underwent dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) twice, i.e., before the first NACRT and after the second NACRT. Patients were assessed for treatment response at 30 days after the second NACRT. Patients were divided into the complete response (CR) and partial response (PR) groups based on their responses to NACRT. Vascular permeability and texture parameters were extracted from the DCE-MRI scans. After assessing the diagnostic performance of individual parameters, a combined model with vascular permeability and texture parameters was generated to predict the response to NACRT.

Results

In this study, the CR and PR groups included 16 patients each. The volume transfer constant (Ktrans), extracellular extravascular volume fraction (ve), and entropy values, as well as changes to each of these parameters, extracted from the second DCE-MRI scans, showed significant differences between the CR and PR groups. The area under the curve (AUC) of Ktrans, ve, and entropy values showed good diagnostic ability (0.813, 0.789, and 0.707, respectively). A logistic regression model combining Ktrans, ve, and entropy had significant diagnostic ability (AUC=0.977).

Conclusions

The use of a combined model with vascular permeability and texture parameters can improve post-NACRT prognostication in patients with ESCC.

Combination of DCE-MRI and DWI in Predicting the Treatment Effect of Concurrent Chemoradiotherapy in Esophageal Carcinoma

Background

Concurrent chemoradiotherapy (CCRT) is the main treatment for esophageal cancer, but the response to treatment varies from individual to individual. MR imaging methods, such as diffusion-weighted (DW) MRI and the use of dynamic contrast-enhanced (DCE) MRI, have the potential to provide additional biomarkers that could evaluate the effect of CCRT in patients with esophageal carcinoma.

Materials and Methods

Fifty-six patients with esophageal carcinoma, verified by histopathology, underwent MRI examination before and at midtreatment (4^th week, radiotherapy 30-40 Gy) using the Siemens 3.0 T MR System. Parameter maps of apparent diffusion coefficient (ADC), and DCE maps of volume transfer constant (K ^rans), rate contrast (k _ep), and extracellular fluid space (v _e), were computed using a Siemens Company Multimodality Workplace (MMWP) model. Comparison of histogram parameters and their diagnostic performance was determined using the Mann-Whitney U test and receiver operating characteristic (ROC) analysis.

Results

56 patient MRI scans were available for analysis at baseline and at the third week, respectively. Pretreatment K ^rans, pretreatment k _ep, pretreatment ADC (P < 0.05), and during-treatment K ^rans (P < 0.05) and ΔK ^rans and ΔADC (P < 0.05) were significantly different after CCRT. Based on the binary logistic model, the ROC analysis demonstrated that the combined predictors demonstrated a high diagnostic performance with an AUC of 0.939. The sensitivity and specificity were 98.6% and 73.8%, respectively.

Conclusion

The combination of DCE and DWI can be used as an early biomarker in the prediction of the effect of CCRT three weeks after treatment in esophageal carcinoma.

The value of GRASP on DCE-MRI for assessing response to neoadjuvant chemotherapy in patients with esophageal cancer

Background

To compare the value of two dynamic contrast-enhanced Magnetic Resonance Images (DCE-MRI) reconstruction approaches, namely golden-angle radial sparse parallel (GRASP) and view-sharing with golden-angle radial profile (VS-GR) reconstruction, and evaluate their values in assessing response to neoadjuvant chemotherapy (nCT) in patients with esophageal cancer (EC).

Methods

EC patients receiving nCT before surgery were enrolled prospectively. DCE-MRI scanning was performed after nCT and within 1 week before surgery. Tumor Regression Grade (TRG) was used for chemotherapy response evaluation, and patients were stratified into a responsive group (TRG1 + 2) and a non-responsive group (TRG3 + 4 + 5). Wilcoxon test was utilized for comparing GRASP and VS-GR reconstruction, Kruskal-Wallis and Mann-Whitney test was performed for each parameter to assess response, and Spearman test was performed for analyzing correlation between parameters and TRGs, as well as responder and non-responder. The receiver operating characteristic (ROC) was utilized for each significant parameter to assess its accuracy between responders and non-responders.

Results

Among the 64 patients included in this cohort (52 male, 12 female; average age of 59.1 ± 7.9 years), 4 patients showed TRG1, 4 patients were TRG2, 7 patients were TRG3, 11 patients were TRG4, and 38 patients were TRG5. They were stratified into 8 responders and 56 non-responders.

A total of 15 parameters were calculated from each tumor. With VS-GR, 10/15 parameters significantly correlated with TRG and response groups. Of these, only AUCmax showed moderate correlation with TRG, 7 showed low correlation and 2 showed negligible correlation with TRG. 8 showed low correlation and 2 showed negligible correlation with response groups. With GRASP, 13/15 parameters significantly correlated with TRG and response groups. Of these, 10 showed low correlation and 3 showed negligible correlation with TRG. 11 showed low correlation and 2 showed negligible correlation with TRG. Seven parameters (AUC^* > 0.70, P < 0.05) showed good performance in response groups.

Conclusions

In patients with esophageal cancer on neoadjuvant chemotherapy, several parameters can differentiate responders from non-responders, using both GRASP and VS-GR techniques. GRASP may be able to better differentiate these two groups compared to VS-GR.

Trial registration for this prospective study: ChiCTR, ChiCTR-DOD-14005308. Registered 2 October 2014.

Histogram analysis of DCE-MRI for chemoradiotherapy response evaluation in locally advanced esophageal squamous cell carcinoma

AIMS

The aim of the study was to predict and assess treatment response by histogram analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to patients with locally advanced esophageal squamous cell carcinoma receiving chemoradiotherapy (CRT).

MATERIALS AND METHODS

Seventy-two patients with locally advanced esophageal squamous cell carcinoma who underwent DCE-MRI before and after chemoradiotherapy were enrolled and divided into the complete response (CR) group and the non-CR group based on RECIST. The histogram parameters (10th percentile, 90th percentile, median, mean, standard deviation, skewness, and kurtosis) of pre-CRT and post-CRT were compared using a paired Student's t test in the CR and non-CR groups, respectively. The histogram parameter differences between the CR and the non-CR groups were compared using an unpaired Student's t test. A receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance.

RESULTS

The histogram parameters of K^trans values were observed to have significantly decreased after chemoradiotherapy in the CR group. The CR responders showed significantly higher median, mean, and 10th and 90th percentile of pre-K^trans values than those of the non-CR group. The histogram analysis indicated the decreased heterogeneity in the CR group after CRT. Esophageal cancer with higher pre-K^trans and lower post-K^trans values indicated a good treatment response to CRT. Pre-K^trans-10th showed the best diagnostic performance in predicting the chemoradiotherapy response.

CONCLUSIONS

The histogram parameters of K^trans are useful in the assessment and prediction of the chemoradiotherapy response in patients with advanced esophageal squamous cell carcinoma. DCE-MRI could serve as an adjunctive imaging technique for treatment planning.

Whole-tumour histogram analysis of pharmacokinetic parameters from dynamic contrast-enhanced MRI in resectable oesophageal squamous cell carcinoma can predict T-stage and regional lymph node metastasis

OBJECTIVE

To identify whether whole-tumour histogram analysis of pharmacokinetic parameters from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could predict T-stage and regional lymph node metastasis (LNM) of resectable oesophageal squamous cell carcinoma (SCC).

MATERIALS AND METHODS

Forty-two consecutive patients with confirmed oesophageal SCC underwent thoracic DCE-MRI. Histogram metrics (median, mean, standard deviation [SD], skewness, kurtosis and entropy) of whole-tumour pharmacokinetic parameters including endothelial transfer constant (Ktrans), reflux rate (Kep) and fractional extravascular extracellular space volume (Ve) were generated by the Omni-Kinetics software. Histogram datasets were interpreted using the Mann-Whitney U test and receiver operating characteristic (ROC) statistical analyses.

RESULTS

The Mann-Whitney U tests revealed that the median, mean and SD of Ktrans, the SD and entropy of Kep, and the median, mean and entropy of Ve of T1-2 stage oesophageal SCC were lower when compared with T3 stage (all Ps < 0.05); and the ROC analysis showed that the entropy of Ve could reliably distinguish T1-2 stage from T3 stage with an area under ROC (AUC) of 0.773. The Mann-Whitney U tests illustrated that the entropy of Ktrans, and the median, mean, SD and entropy of Kep were higher while the skewness of Kep was lower in tumours with LNM than without LNM (all Ps < 0.05); and the ROC analysis demonstrated that the SD of Kep could best identify tumours with LNM with an AUC of 0.702.

CONCLUSION

Whole-tumour histogram analysis of pharmacokinetic parameters of oesophageal SCC on DCE-MRI could be used to predict T-stage and regional LNM.

Assessing Microcirculation in Resectable Oesophageal Squamous Cell Carcinoma with Dynamic Contrast-enhanced MRI for Identifying Primary tumour and Lymphatic Metastasis

This study aimed to determine whether dynamic contrast-enhanced MRI (DCE-MRI) derived parameters can identify oesophageal squamous cell carcinoma (SCC) and lymphatic metastasis. Thirty-nine oesophageal SCC patients underwent DCE-MRI. Quantitative parameters including endothelial transfer constant (Ktrans), reflux rate (Kep), fractional extravascular extracellular space volume and fractional plasma volume, and semi-quantitative parameters including time to peak (TTP), max concentration, Max Slope and area under concentration-time curve of both oesophageal SCC and normal oesophagus were measured. Mann-Whitney U test revealed that Ktrans and Kep of oesophageal SCC were higher while TTP was shorter when compared to normal oesophagus (all P-values < 0.05); and areas under receiver operating characteristic [ROC] curves displayed that Kep was superior to TTP or Ktrans for identifying oesophageal SCC (0.903 vs. 0.832 or 0.713). Mann-Whitney U test also demonstrated that Kep was higher and TTP was shorter in patients with lymphatic metastasis when compared to non-metastatic cancer patients (both P-values < 0.05), and area under ROC curve also showed that TTP was superior to Kep for predicting lymphatic metastasis (0.696 vs. 0.659). In conclusion, the combination of quantitative and semi-quantitative parameters derived from DCE-MRI can aid in the identification of oesophageal SCC and lymphatic metastasis.

Dynamic contrast-enhanced MRI for advanced esophageal cancer response assessment after concurrent chemoradiotherapy

PURPOSE

We aimed to evaluate the treatment response of patients with esophageal cancer after concurrent chemoradiation therapy (CRT) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

METHODS

This retrospective study included 59 patients with histologically confirmed esophageal squamous cell carcinoma. The patients underwent DCE-MRI before and 4 weeks after CRT. Patients with complete response were defined as the CR group; partial response, stable disease, and progressive disease patients were defined as the non-CR group. DCE-MRI parameters (Ktrans, Ve, and Kep) were measured and compared between pre- and post-CRT in the CR and non-CR groups, respectively. Pre-CRT and post-CRT parameters were used to calculate the absolute change and the ratio of change. DCE-MRI parameters were compared between the CR and non-CR groups. Receiver operating characteristic (ROC) curves were used to verify diagnostic performance.

RESULTS

Patients with higher T-stage esophageal cancer might present with poorer response. After CRT, the Ktrans and Kep values significantly decreased in the CR group, whereas only Kep value decreased in the non-CR group. The post-Ktrans and post-Kep values were observed to be significantly lower in the CR group than in the non-CR group. The absolute change and ratio of change of both Ktrans and Kep were higher in the CR group than in the non-CR group. Based on ROC analysis, the ratio of change in Ktrans was the best parameter to assess treatment response (AUC= 0.840).

CONCLUSION

DCE-MRI parameters are valuable in predicting and assessing concurrent CRT response for advanced esophageal cancer.

Role of intravoxel incoherent motion MRI in early assessment of the response of esophageal squamous cell carcinoma to chemoradiotherapy: A pilot study

BACKGROUND

Since definitive concurrent chemoradiotherapy (CRT) is standard therapy for inoperable esophageal squamous cell carcinoma (ESCC), early evaluation of treatment response is crucial for patients and would be useful in assessing response, especially in patients with severe side effects.

PURPOSE

To explore the feasibility of intravoxel incoherent motion (IVIM) MRI in the early assessment of treatment response to CRT.

STUDY TYPE

Prospective.

POPULATION

Twenty-three inoperable ESCC patients.

SEQUENCE

IVIM 3T MRI of nine b values (0, 25, 50, 75, 100, 150, 200, 500 and 800 s/mm² ) was performed at four timepoints: pre-CRT (within 5 days before CRT), mid-CRT (2-3 weeks after the start of CRT), end-CRT (within 5 days after the end of CRT), and post-CRT (1 month after the end of CRT).

ASSESSMENT

IVIM-based parameters and ADC were analyzed independently by two radiologists and treatment response was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST).

STATISTICAL TESTS

Analyses of variance for repeated measurements were conducted to observe dynamic changes of IVIM-based parameters (D, f, and D*) and ADC during CRT. The parameters and their change percentages (Δ%) were compared between complete response (CR) and partial response (PR) by Mann-Whitney U-test. Diagnostic performance of parameters in predicting response was tested with receiver-operating characteristic curve analysis.

RESULTS

ADC, D, and f increased significantly during CRT (P < 0.001, < 0.001, and 0.001, respectively). ADC, f, Δ%ADC, and Δ%D at mid-CRT in CR group were significantly higher than those in the PR group (P = 0.002, 0.013, 0.005, and 0.011, respectively). D combined with f and ADC had highest area under curve (0.917) in identifying CR from PR.

DATA CONCLUSION

IVIM parameters proved useful in assessing response to definitive concurrent CRT for inoperable ESCC and combined with ADC at an early stage of treatment was a good predictor of response.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 4 J. MAGN. RESON. IMAGING 2018;48:349-358.

Dynamic contrast-enhanced MRI for treatment response assessment in patients with oesophageal cancer receiving neoadjuvant chemoradiotherapy

PURPOSE

To explore and evaluate the potential value of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy (nCRT) in oesophageal cancer.

MATERIAL AND METHODS

Twenty-six patients underwent DCE-MRI before, during (week 2-3) and after nCRT, but before surgery (pre/per/post, respectively). Histopathologic tumour regression grade (TRG) was assessed after oesophagectomy. Tumour area-under-the-concentration time curve (AUC), time-to-peak (TTP) and slope were calculated. The ability of these DCE-parameters to distinguish good responders (GR, TRG 1-2) from poor responders (noGR, TRG⩾3), and pathologic complete responders (pCR) from no-pCR was assessed.

RESULTS

Twelve patients (48%) showed GR of which 8 patients (32%) pCR. Analysis of AUC change throughout treatment, AUCper-pre, was most predictive for GR, at a threshold of 22.7% resulting in a sensitivity of 92%, specificity of 77%, PPV of 79%, and a NPV of 91%. AUCpost-pre was most predictive for pCR, at a threshold of -24.6% resulting in a sensitivity of 83%, specificity of 88%, PPV of 71%, and a NPV of 93%. TTP and slope were not associated with pathologic response.

CONCLUSIONS

This study demonstrates that changes in AUC throughout treatment are promising for prediction of histopathologic response to nCRT for oesophageal cancer.

Magnetic resonance imaging for quantitative staging and evaluation of chemoradiotherapeutic effect in esophageal carcinoma

Esophageal carcinoma is a common digestive malignant tumor. Evaluation of the stage and response to chemoradiotherapy of the carcinoma is very important for the treatment decision making and adjustment of therapeutic protocol. To date, a variety of imaging techniques have been used for staging and monitoring response to therapy, but most of the procedures are invasive or of radiation exposure. Moreover, most of the techniques evaluating esophageal cancer are based on morphologic changes. As a non-invasive and non-ionising examination technique, magnetic resonance imaging can quantitatively evaluate this cancer. Nowadays magnetic resonance quantitative technique has progressed greatly in staging and monitoring response to therapy of esophageal carcinoma. This paper focuses on the quantitative evaluation of stage and chemoradiotherapeutic effect in esophageal carcinoma using magnetic resonance imaging.

Assessment of esophageal carcinoma undergoing concurrent chemoradiotherapy with quantitative dynamic contrast-enhanced magnetic resonance imaging

The aim of the present study was to investigate whether quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can predict an early response in primary esophageal carcinoma patients undergoing concurrent chemoradiotherapy. A total of 25 patients with who were pathologically confirmed stage II-III esophageal carcinoma underwent quantitative DCE-MRI prior to chemoradiotherapy, and at 3 weeks post-treatment, the quantitative parameters [K^trans (volume transfer constant; the rate at which contrast agent distributes from the plasma to the EES), K_ep (rate contrast; the rate at which the contrast agent that has diffused to the EES returns to the plasma) and V_e (the contrast agent percentage in the space of the extracellular fluid)] were analyzed respectively. The 25 cases were categorized as a complete response (CR) or a partial response (PR). An independent samples Mann-Whitney U test was used to compare the quantitative parameters between CR and PR. A receiver operating characteristic curve (ROC) was used to determine the best predictor. In total, 17 patients were in the CR group and 8 patients were in the PR group. Pretreatment Ktrans, K_ep and V_e values were 0.54±0.17/min, 1.12±0.46/min and 0.37±0.14, respectively, in the CR group, and 0.40±0.21/min, 1.07±0.37/min and 0.40±0.22, respectively, in the PR group. There was a significant difference between the two groups for K^trans, but there were no significant differences between the two groups for K_ep and V_e. The K^trans, K_ep and V_e values at 3 weeks post-treatment were 0.33±0.11/min, 0.86±0.31/min and 0.66±0.05, respectively, in the CR group, and 0.62±0.22/min, 1.19±0.39/min and 0.45±0.19, respectively, in the PR group. The corresponding U values were -3.319, -1.719 and -2.628, respectively, and the P-values were 0.006, 0.119 and 0.021, respectively. The areas under the ROC curve of K^trans prior to chemoradiotherapy, and of K^trans and K_ep at 3 weeks post-treatment were 0.648, 0.741 and 0.796, respectively. In conclusion, DCE-MRI can predict an early response in primary esophageal carcinoma following 3 weeks of concurrent chemoradiotherapy. K^trans prior to chemoradiotherapy, and K^trans and K_ep at 3 weeks post-treatment are sensitive prediction parameters.

Multimodal approach to assess tumour vasculature and potential treatment effect with DCE-US and DCE-MRI quantification in CWR22 prostate tumour xenografts

The aim of this study was to compare intratumoural heterogeneity and longitudinal changes assessed by dynamic contrast-enhanced ultrasound (DCE-US) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in prostate tumour xenografts. In vivo DCE-US and DCE-MRI were obtained 24 h pre- (day 0) and post- (day 2) radiation treatment with a single dose of 7.5 Gy. Characterization of the tumour vasculature was determined by Brix pharmacokinetic analysis of the time-intensity curves. Histogram analysis of voxels showed significant changes (p < 0.001) from day 0 to day 2 in both modalities for kep , the exchange rate constant from the extracellular extravascular space to the plasma, and kel , the elimination rate constant of the contrast. In addition, kep and kel values from DCE-US were significantly higher than those derived from DCE-MRI at day 0 (p < 0.0001) for both groups. At day 2, kel followed the same tendency for both groups, whereas kep showed this tendency only for the treated group in intermediate-enhancement regions. Regarding kep median values, longitudinal changes were not found for any modality. However, at day 2, kep linked to DCE-US was correlated to MVD in high-enhancement areas for the treated group (p = 0.05). In contrast, correlation to necrosis was detected for the control group in intermediate-enhancement areas (p < 0.1). Intratumoural heterogeneity and longitudinal changes in tumour vasculature were assessed for both modalities. Microvascular parameters derived from DCE-US seem to provide reliable biomarkers during radiotherapy as validated by histology. Furthermore, DCE-US could be a stand-alone or a complementary technique.

FDG Positron Emission Tomography and Computed Tomography Demonstration of Carcinoma Arising in an Epiphrenic Diverticulum

Esophageal carcinoma arising within an epiphrenic diverticulum is rare. We describe a case of a carcinoma in a long-standing epiphrenic diverticulum in a 62-year-old patient. Fluorine-18-2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography and Computed Tomography, and endoscopic ultrasound revealed a hypermetabolic mass within the diverticulum. A preoperative diagnosis was made via endoscopic biopsy. The patient underwent Ivor-Lewis esophagectomy. He remains well and free of recurrence 18 months after surgery.

The application of functional imaging techniques to personalise chemoradiotherapy in upper gastrointestinal malignancies

Functional imaging gives information about physiological heterogeneity in tumours. The utility of functional imaging tests in providing predictive and prognostic information after chemoradiotherapy for both oesophageal cancer and pancreatic cancer will be reviewed. The benefit of incorporating functional imaging into radiotherapy planning is also evaluated. In cancers of the upper gastrointestinal tract, the vast majority of functional imaging studies have used (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). Few studies in locally advanced pancreatic cancer have investigated the utility of functional imaging in risk-stratifying patients or aiding target volume definition. Certain themes from the oesophageal data emerge, including the need for a multiparametric assessment of functional images and the added value of response assessment rather than relying on single time point measures. The sensitivity and specificity of FDG-PET to predict treatment response and survival are not currently high enough to inform treatment decisions. This suggests that a multimodal, multiparametric approach may be required. FDG-PET improves target volume definition in oesophageal cancer by improving the accuracy of tumour length definition and by improving the nodal staging of patients. The ideal functional imaging test would accurately identify patients who are unlikely to achieve a pathological complete response after chemoradiotherapy and would aid the delineation of a biological target volume that could be used for treatment intensification. The current limitations of published studies prevent integrating imaging-derived parameters into decision making on an individual patient basis. These limitations should inform future trial design in oesophageal and pancreatic cancers.

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.

Rectal cancer: dynamic contrast-enhanced MRI correlates with lymph node status and epidermal growth factor receptor expression

PURPOSE

To evaluate correlations between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and clinicopathologic data as well as immunostaining of the markers of angiogenesis epidermal growth factor receptor (EGFR) and CXC-motif chemokine receptor 4 (CXCR4) in patients with rectal cancer.

MATERIALS AND METHODS

Presurgical DCE-MRI was performed in 41 patients according to a standardized protocol. Two quantitative parameters (k21 , A) were derived from a pharmacokinetic two-compartment model, and one semiquantitative parameter (TTP) was assessed. Standardized surgery and histopathologic examinations were performed in all patients. Immunostaining for EGFR and CXCR4 was performed and evaluated with a standardized scoring system.

RESULTS

DCE-MRI parameter A correlated significantly with the N category (P = 0.048) and k21 with the occurrence of synchronous and metachronous distant metastases (P = 0.029). A trend was shown toward a correlation between k21 and EGFR expression (P = 0.107). A significant correlation was found between DCE-MRI parameter TTP and the expression of EGFR (P = 0.044). DCE-MRI data did not correlate with CXCR4 expression.

CONCLUSION

DCE-MRI is a noninvasive method which can characterize microcirculation in rectal cancer and correlates with EGFR expression. Given the relationship between the dynamic parameters and the clinicopathologic data, DCE-MRI data may constitute a prognostic indicator for lymph node and distant metastases in patients with rectal cancer.

Imaging strategies in the management of oesophageal cancer: what's the role of MRI?

OBJECTIVES

To outline the current role and future potential of magnetic resonance imaging (MRI) in the management of oesophageal cancer regarding T-staging, N-staging, tumour delineation for radiotherapy (RT) and treatment response assessment.

METHODS

PubMed, Embase and the Cochrane library were searched identifying all articles related to the use of MRI in oesophageal cancer. Data regarding the value of MRI in the areas of interest were extracted in order to calculate sensitivity, specificity, predictive values and accuracy for group-related outcome measures.

RESULTS

Although historically poor, recent improvements in MRI protocols and techniques have resulted in better imaging quality and the valuable addition of functional information. In recent studies, similar or even better results have been achieved using optimised MRI compared with other imaging strategies for T- and N-staging. No studies clearly report on the role of MRI in oesophageal tumour delineation and real-time guidance for RT so far. Recent pilot studies showed that functional MRI might be capable of predicting pathological response to treatment and patient prognosis.

CONCLUSIONS

In the near future MRI has the potential to bring improvement in staging, tumour delineation and real-time guidance for RT and assessment of treatment response, thereby complementing the limitations of currently used imaging strategies.

KEY POINTS

• MRI's role in oesophageal cancer has been somewhat limited to date. • However MRI's ability to depict oesophageal cancer is continuously improving. • Optimising TN-staging, radiotherapy planning and response assessment ultimately improves individualised cancer care. • MRI potentially complements the limitations of other imaging strategies regarding these points.

Quantitative evaluation of dual-flip-angle T1 mapping on DCE-MRI kinetic parameter estimation in head and neck

PURPOSE

To quantitatively evaluate the kinetic parameter estimation for head and neck (HN) dynamic contrast-enhanced (DCE) MRI with dual-flip-angle (DFA) T1 mapping.

MATERIALS AND METHODS

Clinical DCE-MRI datasets of 23 patients with HN tumors were included in this study. T1 maps were generated based on multiple-flip-angle (MFA) method and different DFA combinations. Tofts model parameter maps of k(ep), K(trans) and v(p) based on MFA and DFAs were calculated and compared. Fitted parameter by MFA and DFAs were quantitatively evaluated in primary tumor, salivary gland and muscle.

RESULTS

T1 mapping deviations by DFAs produced remarkable kinetic parameter estimation deviations in head and neck tissues. In particular, the DFA of [2º, 7º] overestimated, while [7º, 12º] and [7º, 15º] underestimated K(trans) and v(p), significantly (P<0.01). [2º, 15º] achieved the smallest but still statistically significant overestimation for K(trans) and v(p) in primary tumors, 32.1% and 16.2% respectively. k(ep) fitting results by DFAs were relatively close to the MFA reference compared to K(trans) and v(p).

CONCLUSIONS

T1 deviations induced by DFA could result in significant errors in kinetic parameter estimation, particularly K(trans) and v(p), through Tofts model fitting. MFA method should be more reliable and robust for accurate quantitative pharmacokinetic analysis in head and neck.

Rectal cancer: assessment of response to neoadjuvant chemoradiation by dynamic contrast-enhanced MRI

PURPOSE

To assess pretreatment functional and morphological tumor characteristics with magnetic resonance imaging (MRI) in advanced rectal carcinoma and to identify factors predicting response to neoadjuvant chemoradiation.

MATERIALS AND METHODS

In a prospective study, 95 patients with rectal carcinoma underwent dynamic contrast-enhanced MRI before and after chemoradiation. Quantitative parameters were derived from a pharmacokinetic two-compartment model. Tumors were also characterized with regard to mucinous status at pretreatment high-resolution MRI as nonmucinous or mucinous. Response to treatment was defined as a downshift in the local tumor stage.

RESULTS

The parameter k21 (contrast medium exchange rate) was higher at pretreatment MRI in nonmucinous compared with mucinous carcinomas (P < 0.001). The effect of chemoradiation on dynamic MR parameters was higher in nonmucinous carcinomas than in the mucinous subtype (P < 0.001). A higher rate of response to treatment was linked with nonmucinous morphology (P < 0.001). Multivariate analysis revealed an association between mucinous tumor morphology and poor response (odds ratio [95% confidence interval]: 0.113 [0.032-0.395], P < 0.001) as well as an association between a high 75th percentile of k21 and a higher response rate (odds ratio: 1.043 [1.001-1.086], P = 0.019).

CONCLUSION

Functional and morphological parameters of pretreatment MRI can assess tumor characteristics associated with the effectiveness of chemoradiation before treatment initiation.

The principal of dynamic contrast enhanced MRI, the method of pharmacokinetic analysis, and its application in the head and neck region

Many researchers have established the utility of the dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in the differential diagnosis in the head and neck region, especially in the salivary gland tumors. The subjective assessment of the pattern of the time-intensity curve (TIC) or the simple quantification of the TIC, such as the time to peak enhancement (T_peak) and the wash-out ratio (WR), is commonly used. Although the semiquantitative evaluations described above have been widely applied, they do not provide information on the underlying pharmacokinetic analysis in tissue. The quantification of DCE-MRI is preferable; therefore, many compartment model analyses have been proposed. The Toft and Kermode (TK) model is one of the most popular compartment models, which provide information about the influx forward volume transfer constant from plasma into the extravascular-extracellular space (EES) and the fractional volume of EES per unit volume of tissue is used in many clinical studies. This paper will introduce the method of pharmacokinetic analysis and also describe the clinical application of this technique in the head and neck region.

Pharmacokinetic analysis based on dynamic contrast-enhanced MRI for evaluating tumor response to preoperative therapy for oral cancer

PURPOSE

To evaluate whether a pharmacokinetic analysis is useful for monitoring the response of oral cancer to chemoradiotherapy (CRT).

MATERIALS AND METHODS

Twenty-nine patients were included. They underwent dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) before and after CRT. The DCE-MRI data were analyzed using a Tofts and Kermode (TK) model. The histological evaluation of the effects of CRT was performed according to Ohboshi and Shimosato's classification.

RESULTS

None of the pre-CRT parameters were significantly different between the responders and nonresponders. The post-CRT volume of the extravascular extracellular space (EES) per unit volume of tissue (v(e) ) of responders (0.397 ± 0.080) was higher than that of nonresponders (0.281 ± 0.076) (P = 0.01). The change of the v(e) between the pre- and post-CRT of the responders (0.154 ± 0.093) was larger than that of the nonresponders (0.033 ± 0.073) (P = 0.001). Therefore, the increase in the v(e) strongly suggested a good tumor response to CRT, which reflected an increase of the EES secondary to the destruction of the cancer nest. The changes in the volume transfer constant (K(trans) ) were significantly different between the responders and nonresponders (P = 0.018).

CONCLUSION

Both the increase of the v(e) and the elevation of permeability (K(trans) ) were indicative of a good tumor response to CRT. The pharmacokinetic analysis had potential for monitoring the histopathological response to CRT.

Innovation in cancer imaging

Cancer is rapidly becoming the worldwide leading cause of premature death. Iconographic techniques have traditionally provided information on tumor anatomy. The recent introduction of functional and molecular imaging techniques allows probing tumor physiology and biology in addition to mere anatomical description. In addition to the research implications, these novel imaging techniques offer early response assessment and target visualization which, in the era of personalized medicine, may offer significant advances in cancer therapy. Here, we provide an overview of the most important developments in cancer imaging, with a focus on the clinical applications.

Heuristic linear mapping of physiological parameters in dynamic contrast-enhanced MRI without T₁ measurement and contrast agent concentration

PURPOSE

To present a novel heuristic linear mapping method to individually estimate physiological parameters for Tofts model without T(1) measurement and contrast agent concentration.

MATERIALS AND METHODS

A linear relationship was used for k(ep) mapping through a heuristic time intensity curve (TIC) shape factor (TSF). K(trans) maps were subsequently estimated using k(ep) maps and another approximate linear model derived from the Tofts model. Twenty-seven patients with head-and-neck squamous cell carcinoma received dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Physiological parameters maps were obtained using this heuristic linear mapping method and compared to the maps obtained by the normal nonlinear least-square fitting with T(1) measurement.

RESULTS

High linearity (R(2) >0.95) between k(ep) and TSF was found in all patients for k(ep) <5/min. This linearity is robust for TSF timepoint selection. The k(ep) maps generated by this linear fitting were highly consistent with those by the normal nonlinear approach (P > 0.05). The K(trans) maps were consistent with the normally derived maps in pattern distribution but the absolute value might be scaled due to the assumption of the reference K(trans) value.

CONCLUSION

This novel method generates reliable and consistent physiological parameter maps with significantly lower computation complexity than the multiparameter nonlinear fitting. The DCE-MRI scan time can be greatly shortened without T(1) mapping.

Tumoral and nontumoral pancreas: correlation between quantitative dynamic contrast-enhanced MR imaging and histopathologic parameters

PURPOSE

To prospectively determine whether dynamic contrast material-enhanced (DCE) magnetic resonance (MR) quantitative parameters correlate with fibrosis and microvascular density (MVD) in malignant and benign solid pancreatic focal lesions and nontumoral pancreatic tissue.

MATERIALS AND METHODS

The institutional review board approved the study; written informed consent was obtained. DCE MR was performed in 28 patients with surgically resectable focal pancreatic lesions. DCE MR quantitative parameters derived from one-compartment (OC) (transfer rate constant [K(trans)] and distribution fraction [ƒ]) and two-compartment (TC) (K(trans), tissue volume fraction occupied by extravascular extracellular space [v(i)], and tissue volume fraction occupied by vascular space [v(p)]) pharmacokinetic models were correlated with fibrosis content and MVD counts in focal lesions and nontumoral tissue (Spearman correlation coefficient [SCC]). Pharmacokinetic parameters were compared (Mann-Whitney test) between tumoral and nontumoral tissue. Diagnostic performance of DCE MR fibrosis detection was assessed (receiver operator characteristic curve analysis).

RESULTS

K(trans) OC and K(trans) TC were significantly lower in primary malignant tumors compared with benign lesions (P = .023) and nontumoral pancreatic tissue downstream (P < .001) and upstream (P = .006); ƒ and v(i) were significantly higher in primary malignant tumors compared with nontumoral pancreatic tissue downstream (P = .012 and .018, respectively). Fibrosis was correlated negatively with K(trans) OC (SCC, -0.600) and K(trans) TC (SCC, -0.564) and positively with ƒ (SCC, 0.514) and v(i) (SCC, 0.464), with P < .001 (all comparisons). MVD was positively correlated with ƒ (SCC, 0.355; P = .019) and v(i) (SCC, 0.297; P = .038) but not with K(trans) OC (SCC, -0.140; P = .33) and K(trans) TC (SCC, -0.194; P = .181). Sensitivity and specificity for fibrosis detection were 65% (24 of 37) and 83% (10 of 12) for K(trans) OC (cutoff value, 0.35 min(-1)) and 76% (28 of 37) and 83% (10 of 12) for K(trans) TC (cutoff value, 0.29 min(-1)), respectively.

CONCLUSION

Quantitative DCE MR parameters, derived from pharmacokinetic models in malignant and benign pancreatic solid lesions and nontumoral pancreatic tissue, were significantly correlated with fibrosis and MVD.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11103515/-/DC1.

Clinical investigation on application of water swallowing to MR esophagography

OBJECTIVE

To verify the clinical outcomes of applying water swallowing to MR esophagography.

METHODS

Thirty patients confirmed postoperatively or histopathologically with thoracic esophageal carcinoma by endoscopic biopsy and 10 healthy volunteers with normal esophagus underwent respectively conventional magnetic resonance imaging (MRI) detection and water swallowing MR esophagography. Of those patients, 4 underwent second examination after radiotherapy. Assessment on imaging effects of MR esophagography was performed. Assessment on definition on MR esophagography of the tumor in both upper and lower ends, specific localization, tumor size finally measured, coincidence with the gross pathologic types and tumor staging were respectively performed by comparison with conventional MRI. Additionally, we evaluated the outcomes of radiotherapy by comparing the previous MR esophagography with the second one with interventional technique.

RESULTS

Of the total 44 images of MR esophagography, 97.7% (43/44) were in high resolution by sagittal view and 81.8% (36/44) by cross-section. 93.3% (56/60) of the MR esophagography were clearly defined with the neoplastic lesion ends in the 30 patients with thoracic esophageal carcinoma, compared with 11.7% (7/60) by conventional MRI. The results were totally different in statistics (P<0.005). Preoperative conventional MRI detection of the 22 cases in 25 undergone radical resection suggested vague diameter of the primary tumor and impossibly identified it at middle-lower thoracic esophagus in 5, and even failed to confirm gross pathologic types in 19 cases. Yet, MR esophagography with water swallowing represented accurate tumor length (graded as excellent) in 88% (22/25), localization in 100% (25/25), exact gross pathologic types in 88% (22/25), and accuracy for tumor staging in 80.8% (21/26) compared to 92.3% (24/26) by conventional MRI. Therapeutic effects achieved in 4 patients with radiotherapy.

CONCLUSIONS

MR esophagography with water swallowing makes optimal esophagram and is of great value in the preoperative diagnosis of thoracic esophageal cancer and assessment of the radiotherapy effects for patients with such neoplasm, which may serve as an alternative for conventional MRI.

Magnetic resonance in the era of molecular imaging of cancer

Magnetic resonance imaging (MRI) has played an important role in the diagnosis and management of cancer since it was first developed, but other modalities also continue to advance and provide complementary information on the status of tumors. In the future, there will be a major continuing role for noninvasive imaging in order to obtain information on the location and extent of cancer, as well as assessments of tissue characteristics that can monitor and predict treatment response and guide patient management. Developments are currently being undertaken that aim to provide improved imaging methods for the detection and evaluation of tumors, for identifying important characteristics of tumors such as the expression levels of cell surface receptors that may dictate what types of therapy will be effective and for evaluating their response to treatments. Molecular imaging techniques based mainly on radionuclide imaging can depict numerous, specific, cellular and molecular markers of disease and have unique potential to address important clinical and research challenges. In this review, we consider what continuing and evolving roles will be played by MRI in this era of molecular imaging. We discuss some of the challenges for MRI of detecting imaging agents that report on molecular events, but highlight also the ability of MRI to assess other features such as cell density, blood flow and metabolism which are not specific hallmarks of cancer but which reflect molecular changes. We discuss the future role of MRI in cancer and describe the use of selected quantitative imaging techniques for characterizing tumors that can be translated to clinical applications, particularly in the context of evaluating novel treatments.

DCEMRI of spontaneous canine tumors during fractionated radiotherapy: a pharmacokinetic analysis

PURPOSE

To estimate pharmacokinetic parameters from dynamic contrast-enhanced magnetic resonance (DCEMR) images of spontaneous canine tumors taken during the course of fractionated radiotherapy, and to quantify treatment-induced changes in these parameters.

MATERIALS AND METHODS

Six dogs with tumors in the oral or nasal cavity received fractionated conformal radiotherapy with 54 Gy given in 18 fractions. T(1)-weighted DCEMR imaging was performed prior to each treatment fraction. Time-intensity curves in the tumor were extracted voxel-by-voxel, and were fitted to the Brix pharmacokinetic model. The dependence of the pharmacokinetic parameters on the accumulated radiation dose was calculated.

RESULTS

The Brix model reproduced the time-intensity curves well. A reduction in the k(ep) parameter with accumulated radiation dose was found for five (three significant) out of six cases, while the results for the A parameter were less consistent. Both pre-treatment k(ep) and the change in k(ep) with accumulated dose correlated significantly with tumor regression.

CONCLUSIONS

Pharmacokinetic parameters derived from DCEMR images taken during fractionated radiotherapy may predict response to radiotherapy. This may potentially impact on patient stratification and monitoring of treatment response for image-guided treatment strategies.

Simulation-based comparison of two approaches frequently used for dynamic contrast-enhanced MRI

PURPOSE

The purpose was to compare two approaches for the acquisition and analysis of dynamic-contrast-enhanced MRI data with respect to differences in the modelling of the arterial input-function (AIF), the dependency of the model parameters on physiological parameters and their numerical stability. Eight hundred tissue concentration curves were simulated for different combinations of perfusion, permeability, interstitial volume and plasma volume based on two measured AIFs and analysed according to the two commonly used approaches. The transfer constants (Approach 1) K (trans) and (Approach 2) k (ep) were correlated with all tissue parameters. K (trans) showed a stronger dependency on perfusion, and k (ep) on permeability. The volume parameters (Approach 1) v (e) and (Approach 2) A were mainly influenced by the interstitial and plasma volume. Both approaches allow only rough characterisation of tissue microcirculation and microvasculature. Approach 2 seems to be somewhat more robust than 1, mainly due to the different methods of CA administration.

Functional imaging of head and neck cancers

PURPOSE OF REVIEW

Functional imaging including single photon emission computed tomography, PET and MRI techniques in head and neck squamous cell cancer allows disease characterization beyond structure and morphology.

RECENT FINDINGS

In patients without clinical signs of lymph node involvement, sensitivity of fluoro-2-deoxy-D-glucose PET is only 50%. This has led to the use of sentinel lymph node scintigraphy that seems to be a valid alternative to elective stage dissection. Additionally, the use of single-photon emission computed tomography-computed tomography imaging enables a more accurate localization of the sentinel lymph node scintigraphy. The fluoro-2-deoxy-D-glucose uptake intensity of the head and neck squamous cell carcinoma sites is related to locoregional control and overall survival. In case of suspicion for residual or recurrent head and neck squamous cell carcinoma after surgery or (chemo)radiotherapy, fluoro-2-deoxy-D-glucose-PET has a high sensitivity and seems to be cost-effective in selecting patients for direct laryngoscopy. Diffusion-weighted MRI in combination with size and morphological criteria is a strong predictor of presence of malignant lymph nodes. Initial reports indicate the use of diffusion-weighted imaging for response assessment as early as 1 week after beginning of radiochemotherapy. Perfusion MRI is studied for the measurement of drug effects on tumour (micro)vascularity and capillary permeability.

SUMMARY

Functional imaging improves the initial staging and the detection of residual or recurrent disease following therapy.