Diffusion-weighted magnetic resonance imaging in colorectal cancer

T2-weighted imaging-based radiomic-clinical machine learning model for predicting the differentiation of colorectal adenocarcinoma

BACKGROUND

The study on predicting the differentiation grade of colorectal cancer (CRC) based on magnetic resonance imaging (MRI) has not been reported yet. Developing a non-invasive model to predict the differentiation grade of CRC is of great value.

AIM

To develop and validate machine learning-based models for predicting the differentiation grade of CRC based on T2-weighted images (T2WI).

METHODS

We retrospectively collected the preoperative imaging and clinical data of 315 patients with CRC who underwent surgery from March 2018 to July 2023. Patients were randomly assigned to a training cohort (n = 220) or a validation cohort (n = 95) at a 7:3 ratio. Lesions were delineated layer by layer on high-resolution T2WI. Least absolute shrinkage and selection operator regression was applied to screen for radiomic features. Radiomics and clinical models were constructed using the multilayer perceptron (MLP) algorithm. These radiomic features and clinically relevant variables (selected based on a significance level of P < 0.05 in the training set) were used to construct radiomics-clinical models. The performance of the three models (clinical, radiomic, and radiomic-clinical model) were evaluated using the area under the curve (AUC), calibration curve and decision curve analysis (DCA).

RESULTS

After feature selection, eight radiomic features were retained from the initial 1781 features to construct the radiomic model. Eight different classifiers, including logistic regression, support vector machine, k-nearest neighbours, random forest, extreme trees, extreme gradient boosting, light gradient boosting machine, and MLP, were used to construct the model, with MLP demonstrating the best diagnostic performance. The AUC of the radiomic-clinical model was 0.862 (95%CI: 0.796-0.927) in the training cohort and 0.761 (95%CI: 0.635-0.887) in the validation cohort. The AUC for the radiomic model was 0.796 (95%CI: 0.723-0.869) in the training cohort and 0.735 (95%CI: 0.604-0.866) in the validation cohort. The clinical model achieved an AUC of 0.751 (95%CI: 0.661-0.842) in the training cohort and 0.676 (95%CI: 0.525-0.827) in the validation cohort. All three models demonstrated good accuracy. In the training cohort, the AUC of the radiomic-clinical model was significantly greater than that of the clinical model (P = 0.005) and the radiomic model (P = 0.016). DCA confirmed the clinical practicality of incorporating radiomic features into the diagnostic process.

CONCLUSION

In this study, we successfully developed and validated a T2WI-based machine learning model as an auxiliary tool for the preoperative differentiation between well/moderately and poorly differentiated CRC. This novel approach may assist clinicians in personalizing treatment strategies for patients and improving treatment efficacy.

The Multipurpose Usage of Diffusion-Weighted MRI in Rectal Cancer

Background and Objectives: Colorectal cancer is the third most common oncological disease worldwide. The standard treatment of locally advanced rectal tumors is neoadjuvant radiochemotherapy in combination with surgical resection. The choice of specific treatment algorithm is highly dependent on MRI findings. The aim of this study is to show the potential role of ADC measurements in rectal cancer and their usage in different clinical scenarios. Materials and Methods: A total of 135 patients had rectal MRI evaluation. Seventy-five (56%) had histologically proven rectal adenocarcinoma and sixty (44%) were evaluated as rectal disease-free. An ADC measurement in the most prominent region of interest was obtained for all patients. Eighteen patients (24% of the rectal cancer group) had a second MRI after neoadjuvant chemoradiotherapy with comparison of the ADC values at the same region of interest as previously measured. Results: Rectal cancer ADC values were found to be significantly lower than the ones in the control group (p < 0.001). A statistically significant correlation was found when ADC values in rectal tumors of different T stages were compared (p = 0.039)-those with higher T stage as in locally advanced disease showed lower ADC values. Patients with extramural vascular invasion showed significantly lower ADC values (p = 0.01). There was a significant increase in ADC values after treatment (p < 0.001), and a negative correlation was observed (r = -0.6572; p = 0.004)-tumors with low initial ADC values showed a higher increase in ADC. Conclusions: ADC measurements have a complementary role in the assessment of rectal cancer and have the potential to predict the response to chemoradiotherapy and improve the planning of proper treatment strategies.

Validation of a Nomogram to Predict Recurrence in Patients with Mucinous Neoplasms of the Appendix with Peritoneal Dissemination After Cytoreductive Surgery and HIPEC

BACKGROUND

Survival of patients affected by mucinous appendiceal neoplasms with peritoneal dissemination (PD) is mainly related to histopathological features. However, prognostic stratification is still a concern, as the clinical course of the disease is often unpredictable. The aim of this study is to construct and externally validate a nomogram predicting disease-free survival (DFS) in mucinous appendiceal neoplasms with PD treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).

PATIENTS AND METHODS

Patients treated in two referral centers were included: Hospital General Universitario Gregorio Marañón, Madrid, Spain (derivation cohort) and Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy (validation cohort). Cox regression analysis identified factors associated with shorter DFS in the derivation cohort. The nomogram performance was externally evaluated in the validation cohort using concordance index and calibration plots. Histology was classified according to the Peritoneal Surface Oncology Group International (PSOGI).

RESULTS

The derivation cohort included 95 patients, and the validation cohort 348. Five-year DFS rates were 51.5 and 62%, respectively. Cox regression analysis (derivation cohort) identified PSOGI histology of the peritoneal components, number of preoperative elevated tumor marker, and peritoneal disease extent, as assessed by peritoneal carcinomatosis index, to be predictors of DFS. The model's predictive capacity was higher than that of PSOGI classification alone, with respective concordance indexes of 0.702 ± 0.023 and 0.610 ± 0.018 (validation cohort). The nomogram approximated the perfect model in the calibration plots at 3- and 5-year DFS.

CONCLUSIONS

An easy-to-use model that provides better prognostic stratification than histopathological features has been constructed. This nomogram may help clinicians in individualized survival predictions and informed clinical decision-making.

Diagnostic performance of [18F]-FDG PET/MR in evaluating colorectal cancer: a systematic review and meta-analysis

PURPOSE

To calculate the diagnostic performance of [¹⁸F]-FDG PET/MR in colorectal cancer (CRC).

METHODS

This study was designed following the PRISMA-DTA guidelines. To be included, published original articles (until December 31, 2021) that met the following criteria were considered eligible: (1) evaluated [¹⁸F]-FDG PET/MR as the diagnostic method to detect CRC; (2) compared [¹⁸F]-FDG PET/MR with histopathology as the reference standard, or clinical/imaging composite follow-up when pathology was not available; (3) provided adequate crude data for meta-analysis. The diagnostic pooled measurements were calculated at patient and lesion levels. Regarding sub-group analysis, diagnostic measurements were calculated in "TNM staging," "T staging," "N staging," "M staging," and "liver metastasis" sub-groups. Additionally, we calculated the pooled performances in "rectal cancer: patient-level" and "rectal cancer: lesion-level" sub-groups. A hierarchical method was used to pool the performances. The bivariate model was conducted to find the summary points. Analyses were performed using STATA 16.

RESULTS

A total of 1534 patients from 18 studies were entered. The pooled sensitivities in CRC lesion detection (tumor, lymph nodes, and metastases) were 0.94 (95%CI: 0.89-0.97) and 0.93 (95%CI: 0.82-0.98) at patient-level and lesion-level, respectively. The pooled specificities were 0.89 (95%CI: 0.84-0.93) and 0.95 (95%CI: 0.90-0.98) at patient-level and lesion-level, respectively. In sub-groups, the highest sensitivity (0.97, 95%CI: 0.86-0.99) and specificity (0.99, 95%CI: 0.84-1.00) were calculated for "M staging" and "rectal cancer: lesion-level," respectively. The lowest sensitivity (0.81, 95%CI: 0.65-0.91) and specificity (0.79, 95%CI: 0.52-0.93) were calculated for "N staging" and "T staging," respectively.

CONCLUSION

This meta-analysis showed an overall high diagnostic performance for [¹⁸F]-FDG PET/MR in detecting CRC lesions/metastases. Thus, this modality can play a significant role in several clinical scenarios in CRC staging and restaging. Specifically, one of the main strengths of this modality is ruling out the existence of CRC lesions/metastases. Finally, the overall diagnostic performance was not found to be affected in the post-treatment setting.

A comparison of liver MRI and contrast enhanced CT as standard workup before treatment for rectal cancer in usual care - a Retrospective Study

BACKGROUND

The liver is the most common site for rectal cancer metastases. Recommended standard pre-treatment workup has involved computed tomography (CT) for abdominal metastases. However, few hospitals have replaced this with magnetic resonance imaging (MRI).

INTRODUCTION

The aim of this study was to compare MRI with CT as an index examination of the liver in the pre-treatment workup in usual care. The primary endpoint was the need for supplementary liver investigations.

METHOD

Consecutive patients from two hospitals during 2013-2015 were identified in the Regional Swedish Colorectal Cancer Register and included in this retrospective study. Hospital records and radiology reports were reviewed. Inconclusive reports were re-evaluated by two radiologists.

RESULT

A total of 320 patients were included, and 293 were available for analysis. Some 175 and 118 patients had undergone CT and MRI, respectively, as their index pretreatment liver examination. Thirty-four (19.4%) in the CT group and 6 (5.1%) patients in the MRI group underwent supplementary liver investigation due to inconclusive index examination (RR 3.82, 95% CI: 1.66;8.81, p=0.0017). Median time (q1;q3) from index examination to start of treatment was 50 (36;68) days in the CT group and 34 (27;45) days in the MRI group.

CONCLUSION

This retrospective study of two modalities within usual care found that MRI of the liver as index radiological workup before treatment for rectal cancer was associated with fewer supplementary liver investigations and a shorter time to start treatment. Based on these findings, a prospective trial should be undertaken before implementing MRI as a standard.

A Comparison of CT Manifestations between Coronavirus Disease 2019 (COVID-19) and Other Types of Viral Pneumonia

BACKGROUND

Though imaging manifestations of COVID-19 and other types of viral pneumonia are similar, their clinical treatment methods differ. Accurate, non-invasive diagnostic methods using CT imaging can help developing an optimal therapeutic regimen for both conditions.

OBJECTIVES

To compare the initial CT imaging features in COVID-19 with those in other types of viral pneumonia.

METHODS

Clinical and imaging data of 51 patients with COVID-19 and 69 with other types of viral pneumonia were retrospectively studied. All significant imaging features (Youden index >0.3) were included for constituting the combined criteria for COVID-19 diagnosis, composed of two or more imaging features with a parallel model. McNemar's chi-square test or Fisher's exact test was used to compare the validity indices (sensitivity and specificity) among various criteria.

RESULTS

Ground glass opacities (GGO) dominated density, peripheral distribution, unilateral lung, clear margin of lesion, rounded morphology, long axis parallel to the pleura, vascular thickening, and crazy-paving pattern were more common in COVID-19 (p <0.05). Consolidation-dominated density, both central and peripheral distribution, bilateral lung, indistinct margin of lesion, tree-in-bud pattern, mediastinal or hilar lymphadenectasis, pleural effusion, and pleural thickening were more common in other types of viral pneumonia (p < 0.05). GGO-dominated density or long axis parallel to the pleura (with the highest sensitivity), and GGO-dominated density or long axis parallel to the pleura or vascular thickening (with the highest specificity) are good combined criteria of COVID-19.

CONCLUSION

The initial CT imaging features are helpful for differential diagnosis between COVID-19 and other types of viral pneumonia.

Diffusional kurtosis imaging in evaluation of microstructural changes of spinal cord in cervical spondylotic myelopathy feasibility study

To explore the value of diffusion kurtosis imaging in the changes of spinal cord microstructures in patients with early cervical spondylotic myelopathy.Twenty nine patients with cervical myelopathy were selected in this study. All images were acquired on a 3.0 T MR scanner (Skyra, Siemens Medical Systems, Germany). The imaging parameters for diffusion kurtosis imaging were as follows: repetition time/echo time, 3000/91 ms; averages, 2; slice thickness/gap, 3/0.3 mm; number of slices, 17; field of view, 230 × 230 mm; Voxel size, 0.4 × 0.4 × 3.0 mm; 3 b-values (0, 1000, and 2000 s/mm) with diffusion encoding in 20 directions for each b-value. Values for fractional anisotropy, mean diffusivity, and mean diffusional kurtosis (MK) were calculated and compared between unaffected and affected spinal cords.In all patients MK was significantly lower in normal appearing spinal cords adjacent to the affected cervical spinal cords than in normal cervical spinal cords (0.862 ± 0.051 vs 0.976 ± 0.0924, P < .0001), but the difference of fractional anisotropy and apparent diffusion coefficient was no significant (P > .05). The affected cervical spinal cords had lower MK (0.716 ± 0.0753), FA and higher apparent diffusion coefficient than normal cervical spinal cords (P < .001).MK values in the cervical spinal cord may reflect microstructural changes of spinal cord damage in cervical myelopathy, and it could potentially provide more information that obtained with conventional diffusion metrics.

Extent of Peritoneal Metastases on Preoperative DW-MRI is Predictive of Disease-Free and Overall Survival for CRS/HIPEC Candidates with Colorectal Cancer

OBJECTIVE

The aim of this study was to determine whether the extent of peritoneal metastases (PMs) on preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) can be used as a biomarker of disease-free and overall survival in patients with colorectal cancer who are considered for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).

METHODS

For this retrospective cohort study, patients with PMs considered for CRS/HIPEC who underwent DW-MRI for preoperative staging in 2016-2017 were included. The DW-MRI protocol consisted of diffusion-weighted, T2-weighted, and pre- and post-gadolinium T1-weighted imaging of the chest, abdomen, and pelvis. DW-MRI images were evaluated by two independent readers to determine the extent of PMs represented by the Peritoneal Cancer Index (MRI-PCI), as well as extraperitoneal metastases. Cox regression and Kaplan-Meier analysis was performed to determine the prognostic value of DW-MRI for overall and disease-free survival.

RESULTS

Seventy-eight patients were included. CRS/HIPEC was planned for 53 patients and completed in 50 patients (60.5%). Median follow-up after DW-MRI was 23 months (interquartile range 13-24). The MRI-PCI of both readers showed prognostic value for overall survival, independently of whether R1 resection was achieved (hazard ratio [HR] 1.06-1.08; p < 0.05). For the patients who received successful CRS/HIPEC, the MRI-PCI also showed independent prognostic value for disease-free survival for both readers (HR 1.09-1.10; p < 0.05).

CONCLUSION

The extent of PMs on preoperative DW-MRI is an independent predictor of overall and disease-free survival and should therefore be considered as a non-invasive prognostic biomarker.

Current state of the art imaging approaches for colorectal liver metastasis

One of the most common cancers worldwide, colorectal cancer (CRC) has been associated with significant morbidity and mortality and therefore represents an enormous burden to the health care system. Recent advances in CRC treatments have provided patients with primary and metastatic CRC a better long-term prognosis. The presence of synchronous or metachronous metastasis has been associated, however, with worse survival. The most common site of metastatic disease is the liver. A variety of treatment modalities aimed at targeting colorectal liver metastases (CRLM) has been demonstrated to improve the prognosis of these patients. Loco-regional approaches such as surgical resection and tumor ablation (operative and percutaneous) can provide patients with a chance at long-term disease control and even cure in select populations. Patient selection is important in defining the most suitable treatment option for CRLM in order to provide the best possible survival benefit while avoiding unnecessary interventions and adverse events. Medical imaging plays a crucial role in evaluating the characteristics of CRLMs and disease resectability. Size of tumors, proximity to adjacent anatomical structures, and volume of the unaffected liver are among the most important imaging parameters to determine the suitability of patients for surgical management or other appropriate treatment approaches. We herein provide a comprehensive overview of current-state-of-the-art imaging in the management of CRLM, including staging, treatment planning, response and survival assessment, and post-treatment surveillance. Computed tomography (CT) scan and magnetic resonance imaging (MRI) are two most commonly used techniques, which can be used solely or in combination with functional imaging modalities such as positron emission tomography (PET) and diffusion weighted imaging (DWI). Providing up-to-date evidence on advantages and disadvantages of imaging modalities and tumor assessment criteria, the current review offers a practice guide to assist providers in choosing the most suitable imaging approach for patients with CRLM.

MAGNETIC RESONANCE IMAGING WITH DIFFUSE WEIGHTED IMAGING AND COMPUTED TOMOGRAPHY WITH INTRAVENOUS CONTRAST IN STAGING OF DISSEMINATED OVARIAN, STOMACH, COLORECTAL CANCER

The aim of the research. Development and implementation of new methods for pre-operative staging of advanced ovarian, gastric and colorectal cancer to improve patient selection for cytoreductive surgery and increase its radicality. Materials and methods. Data from 120 patients with advanced ovarian cancer, 28 with advanced gastric cancer and 119 with advanced colorectal cancer were analyzed. Preoperative detection of the incidence of peritoneal carcinoma and the possibility of surgery in radical or cytoreductive volume performed by CT with intravenous contrast (72 patients with ovarian cancer, 17 patients with gastric cancer, and 69 patients with colorectal cancer), and MR T1 and T2, contrast-enhanced T1, and diffuse-weighted sequences (48 patients with ovarian cancer, 11 patients with gastric cancer, and 50 patients with colorectal cancer). Subsequently, preoperative and intraoperative assessment of the prevalence of the tumour process with peritoneal carcinoma index (PCI) by Sugarbaker was performed. Results. A statistically significant increase in the informativeness of the preoperative assessment of the incidence of tumour process in peritoneum and the presence of distant metastases using DWI / MRI compared with CT with intravenous contrast was determined. Patients from all groups were categorized according to the completeness index of cytoreduction achieved by preoperative staging and patient selection using DWI / MRI and CT. The use of DWI / MRI allowed to significantly reduce the number of suboptimal and non-optimal cytoreductive interventions. Conclusions. DWI / MRI has made it possible to significantly improve the preoperative incidence of advanced ovarian, gastric, and colorectal cancer compared to CT, predict the radicality of future surgery, and detect inoperable cases.

Whole-body diffusion-weighted MRI for operability assessment in patients with colorectal cancer and peritoneal metastases

Background

Correct staging of patients with colorectal cancer is of utmost importance for the prediction of operability. Although computed tomography (CT) has a good overall performance, estimation of peritoneal cancer spread is a known weakness, a problem that cannot always be overcome by Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT); especially in infiltrative and miliary disease spread. Due to its high spatial and contrast resolution magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) might have a better performance. Our aim was to evaluate the added value of whole-body diffusion-weighted MRI (WB-DWI/MRI) to CT for prediction of peritoneal cancer spread and operability assessment in colorectal cancer patients with clinically suspected peritoneal carcinomatosis (PC).

Methods

This institutional review board approved retrospective study included sixty colorectal cancer patients who underwent WB-DWI/MRI in addition to CT for clinically suspected peritoneal metastases. WB-DWI/MRI and CT were assessed for detecting PC following the peritoneal cancer index (PCI), determination of PCI-score categorized as PC < 12, PCI = 12–15 and PCI > 15, detection of nodal and distant metastases and estimation of overall operability. Histopathology after surgery and biopsy and/or 6 months follow-up were used as reference standard.

Results

For detection of PC, CT had 43.2% sensitivity, 95.6% specificity, 84.5% positive predictive value (PPV) and 75.2% negative predictive value (NPV). WB-DWI/MRI had 97.8% sensitivity, 93.2% specificity, 88.9% PPV and 98.7% NPV. WB-DWI/MRI enabled better detection of inoperable distant metastases (all 12 patients) than CT (2/12 patients) and significantly improved prediction of PCI category [WB-DWI/MRI PCI < 12: 37/39 patients (94.9%); PCI = 12–15: 4/4 patients (100%); PCI > 15: 16/17 patients (94.1%) versus CT PCI < 12: 38/39 patients (97.4%); PCI = 12–15: 0/4 patients (0%); PCI > 15: 2/17 patients (11.8%); p < 0.0001)]. WB-DWI/MRI improved prediction of inoperability over CT with 90.6% sensitivity compared to 25% (p < 0.0001).

Conclusions

WB-DWI/MRI significantly outperformed CT for estimation of spread of PC, overall staging and prediction of operability. Pending validation in larger prospective trials, WB-DWI/MRI could be used to guide surgical planning and minimize unnecessary exploratory laparotomies.

Noninvasive Biomarkers of Colorectal Cancer: Role in Diagnosis and Personalised Treatment Perspectives

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. It has been estimated that more than one-third of patients are diagnosed when CRC has already spread to the lymph nodes. One out of five patients is diagnosed with metastatic CRC. The stage of diagnosis influences treatment outcome and survival. Notwithstanding the recent advances in multidisciplinary management and treatment of CRC, patients are still reluctant to undergo screening tests because of the associated invasiveness and discomfort (e.g., colonoscopy with biopsies). Moreover, the serological markers currently used for diagnosis are not reliable and, even if they were useful to detect disease recurrence after treatment, they are not always detected in patients with CRC (e.g., CEA). Recently, translational research in CRC has produced a wide spectrum of potential biomarkers that could be useful for diagnosis, treatment, and follow-up of these patients. The aim of this review is to provide an overview of the newer noninvasive or minimally invasive biomarkers of CRC. Here, we discuss imaging and biomolecular diagnostics ranging from their potential usefulness to obtain early and less-invasive diagnosis to their potential implementation in the development of a bespoke treatment of CRC.

Monitoring Crohn's disease activity: endoscopy, fecal markers and computed tomography enterography

BACKGROUND

The treatment goal of Crohn's disease (CD) has moved towards achieving mucosal healing, resolution of transmural inflammation, and normalization of biomarkers. The purpose of this study was to evaluate how well computed tomography enterography (CTE) and fecal calprotectin (FC) correlated with endoscopic activity in newly diagnosed patients with CD and after 1 year of therapy.

METHODS

Consecutive patients with newly diagnosed CD were evaluated by endoscopy, CTE, and FC at diagnosis and 12 months after beginning immunosuppression. Endoscopic severity was assessed using the Simplified Endoscopic Score for Crohn's Disease (SES-CD). Biomarkers, clinical indexes, and FC were recorded on the day of ileocolonoscopy at diagnosis and 1 year after diagnosis. We adapted a CTE score for disease activity based on radiological signs of inflammation (i.e. mural thickness, mural hyperenhancement, mesenteric fat proliferation, mesenteric fat densification, comb sign, presence of strictures, fistulas, abscesses, ascites, and lymphadenopathy). Correlations between endoscopy, CTE, and FC were assessed using Spearman's rank correlation.

RESULTS

A total of 29 patients (48% women; median age 30 (24.5-35.5) years) were included in this prospective cohort. CTE findings significantly correlated with endoscopic findings. Endoscopic remission (ER) at 1-year follow up significantly correlated with improvement in mural hyperenhancement (p = 0.004), mesenteric fat densification (p = 0.001), comb sign (p = 0.004), and strictures (p = 0.008) in CTE. None of the CTE findings improved in patients without ER. FC correlated with SES-CD (rs = 0.696, p < 0.001) and with CTE features of inflammation (rs = 0.596, p < 0.001). A cut-off of 100 µg/g predicted ER with 92% sensitivity, 65% specificity, and 83% accuracy (area under curve 0.878, p < 0.001).

CONCLUSIONS

CTE findings and FC levels correlated with endoscopic activity in CD both at diagnosis and at 1-year follow up. These two noninvasive markers of disease activity may be used as an alternative to endoscopy to monitor disease response to therapy.

Preoperative assessment of peritoneal carcinomatosis of colorectal origin

The goal of preoperative assessment of patients with peritoneal carcinomatosis (PC) from colorectal origin is to select candidates for curative surgery by evaluating the possibility of complete resection, and to plan the surgical procedure. Quantitative and qualitative evaluation of lesional localization remains difficult even with current technical progress in imaging. Computed tomography (CT), the reference imaging technique, allows detection of both peritoneal and extra-peritoneal lesions. Sensitivity and specificity for detecting PC are 83% (95%CI: 79-86%) and 86% (95%CI: 82-89%), respectively. Functional imaging, with diffusion-weighted magnetic resonance imaging (MRI) and positron emission tomography PET-CT allows efficient exploration of peritoneal lesions. MRI is operator-dependent, with a long learning curve, and is, at present, essentially used only in expert centers. A standardized protocol provided by the radiologists working with the French National Center for rare peritoneal tumors RENA-RAD (http://www.renape-online.fr/fr/espace-professionnel/rena-rad.html) is however available on line. PET-CT is particularly useful for identifying and defining extra-peritoneal disease. Combining imaging techniques, particular CT with MRI, seems to improve the calculation of the Peritoneal Cancer Index compared to CT alone. Surgical exploration is the reference technique to evaluate PC. Currently, the literature cannot confirm whether laparoscopy performs as well as laparotomy, but laparoscopy is, de facto, the fundamental tool to decrease the number of unnecessary laparotomies in these patients. To optimize the pre-, intra- and postoperative reporting of the extent of PC, the French National Network for management of PC (RENAPE and BIG-RENAPE: http://www.e-promise.org/) has offered on-line a free-of-charge, standardized, multidisciplinary and transversal software.

Diagnostic value of whole-body MRI with diffusion-weighted sequence for detection of peritoneal metastases in colorectal malignancy

Objective:

To assess the diagnostic accuracy of whole-body MRI using diffusion-weighted sequence (WB-DWI) to determine the peritoneal cancer index (PCI) in correlation with surgical and histopathological findings.

Methods:

Twenty-seven patients underwent preoperative WB-MRI, followed by cytoreductive surgery for primary tumors of the appendix (n = 15), colorectum (n = 12), and associated peritoneal disease. A total of 351 regions were retrospectively reviewed. The sensitivity, specificity, and accuracy were calculated at 13 anatomical sites. The WB-DWI PCI and PCI type were compared with surgical and histopathological findings.

Results:

No statistical difference was found between the WB-DWI PCI and surgical PCI (P = 0.574). WB-DWI correctly predicted the PCI type in 24 of 27 patients with high accuracy (88.9%), including 10 of 10 patients with small-volume tumor, 12 of 14 with moderate-volume tumor, and 2 of 3 with large-volume tumor. WB-DWI correctly depicted tumors in 163 of 203 regions, with 40 false-negative and 23 false-positive regions. The overall sensitivity, specificity, and accuracy of WB-DWI for the detection of peritoneal tumors were 80.3%, 84.5%, and 82.1%, respectively. For lesions < 0.5 cm in diameter, WB-DWI demonstrated good sensitivity (69.4%).

Conclusions:

WB-DWI accurately predicted PCI before surgery in patients undergoing evaluation for cytoreductive surgery.

Liver metastases: Detection and staging

The liver is more often involved with metastatic disease than primary liver tumors. The accurate detection and characterization of liver metastases are crucial since patient management depends on it. The imaging options, mainly consisting of contrast-enhanced ultrasound (CEUS), multidetector computed tomography (CT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI), extra-cellular contrast media and liver-specific contrast media as well as positron emission tomography/computed tomography (PET/CT), are constantly evolving. PET/MRI is a more recent hybrid method and a topic of major interest concerning liver metastases detection and characterization. This review gives a brief overview about the spectrum of imaging findings and focus on an update about the performance, advantages and potential limitations of each modality as well as current developments and innovations.

Is MRI of the Liver Needed During Routine Preoperative Workup for Colorectal Cancer?

BACKGROUND

The clinical efficacy of gadoxetic acid-enhanced liver MRI as a routine preoperative procedure for all patients with colorectal cancer remains unclear.

OBJECTIVE

The purpose of this study was to evaluate the efficacy of preoperative gadoxetic acid-enhanced liver MRI for the diagnosis of liver metastasis in patients with colorectal cancer.

DESIGN

This was a retrospective analysis from a prospective cohort database.

SETTINGS

All of the patients were from a subspecialty practice at a tertiary referral hospital.

PATIENTS

Patients who received preoperative gadoxetic acid-enhanced liver MRI after CT and attempted curative surgery for colorectal cancer were included.

MAIN OUTCOME MEASURES

The number of equivocal hepatic lesions based on CT and gadoxetic acid-enhanced liver MRI and diagnostic use of the gadoxetic acid-enhanced liver MRI were measured.

RESULTS

We reviewed the records of 690 patients with colorectal cancer. Equivocal hepatic lesions were present in 17.2% of patients based on CT and in 4.5% based on gadoxetic acid-enhanced liver MRI. Among 496 patients with no liver metastasis based on CT, gadoxetic acid-enhanced liver MRI detected equivocal lesions in 15 patients and metastasis in 3 patients. Among 119 patients who had equivocal liver lesions on CT, gadoxetic acid-enhanced liver MRI indicated hepatic lesions in 103 patients (86.6%), including 90 with no metastasis and 13 with metastasis. Among 75 patients who had liver metastasis on CT, gadoxetic acid-enhanced liver MRI indicated that the hepatic lesions in 2 patients were benign, in contrast to CT findings. The initial surgical plans for hepatic lesions according to CT were changed in 17 patients (3%) after gadoxetic acid-enhanced liver MRI.

LIMITATIONS

This study was limited by its retrospective design.

CONCLUSIONS

The clinical efficacy of gadoxetic acid-enhanced liver MRI as a routine preoperative procedure for all patients with colorectal cancer is low, in spite of its high diagnostic value for detecting liver metastasis. However, this study showed gadoxetic acid-enhanced liver MRI was helpful in characterizing equivocal hepatic lesions identified in CT and could lead to change in treatment plans for some patients. See Video Abstract at http://links.lww.com/DCR/A420.

Multidisciplinary Treatment for Colorectal Peritoneal Metastases: Review of the Literature

Peritoneum is one of the common sites of metastasis in advanced stage colorectal cancer patients. Colorectal cancer patients with peritoneal metastases (PM) are traditionally believed to have poor prognosis, which indicates it is of no value to adopt surgical treatment. With the advancement of surgical techniques, hyperthermic intraperitoneal chemotherapy (HIPEC), and multidisciplinary treatment in recent years, the cognition and treatment strategies of colorectal peritoneal metastases (CPM) have changed dramatically. In terms of prognosis, CPM under the palliative systemic treatment shows an inferior outcome compared with nonperitoneal metastasis. Nevertheless, some CPM patients amenable to the complete peritoneal cytoreductive surgery (CRS) combined with HIPEC may achieve long-term survival. The prognostic factors of CPM comprise peritoneal carcinomatosis index (PCI), completeness of cytoreduction score (CC score), the presence of extraperitoneal metastasis (liver, etc.), Peritoneal Surface Disease Severity Score (PSDSS), Japanese peritoneal staging, and so forth. Taken together, literature data suggest that a multimodality approach combining complete peritoneal CRS plus HIPEC, systemic chemotherapy, and targeted therapy may be the best treatment option for PM from colorectal cancer.