Radiomics modelling in rectal cancer to predict disease-free survival: evaluation of different approaches.

BACKGROUND: Radiomics may be useful in rectal cancer management. The aim of this study was to assess and compare different radiomics approaches over qualitative evaluation to predict disease-free survival (DFS) in patients with locally advanced rectal cancer treated with neoadjuvant therapy. METHODS: Patients from a phase II, multicentre, randomized study (GRECCAR4; NCT01333709) were included retrospectively as a training set. An independent cohort of patients comprised the independent test set. For both time points and both sets, radiomic features were extracted from two-dimensional manual segmentation (MS), three-dimensional (3D) MS, and from bounding boxes. Radiomics predictive models of DFS were built using a hyperparameters-tuned random forests classifier. Additionally, radiomics models were compared with qualitative parameters, including sphincter invasion, extramural vascular invasion as determined by MRI (mrEMVI) at baseline, and tumour regression grade evaluated by MRI (mrTRG) after chemoradiotherapy (CRT). RESULTS: In the training cohort of 98 patients, all three models showed good performance with mean(s.d.) area under the curve (AUC) values ranging from 0.77(0.09) to 0.89(0.09) for prediction of DFS. The 3D radiomics model outperformed qualitative analysis based on mrEMVI and sphincter invasion at baseline (P = 0.038 and P = 0.027 respectively), and mrTRG after CRT (P = 0.017). In the independent test cohort of 48 patients, at baseline and after CRT the AUC ranged from 0.67(0.09) to 0.76(0.06). All three models showed no difference compared with qualitative analysis in the independent set. CONCLUSION: Radiomics models can predict DFS in patients with locally advanced rectal cancer.

Early MRI predictors of disease-free survival in locally advanced rectal cancer from the GRECCAR 4 trial.

BACKGROUND: Tailored neoadjuvant treatment of locally advanced rectal cancer (LARC) may improve outcomes. The aim of this study was to determine early MRI prognostic parameters with which to stratify neoadjuvant treatment in patients with LARC. METHODS: All patients from a prospective, phase II, multicentre randomized study (GRECCAR4; NCT01333709) were included, and underwent rectal MRI before treatment, 4 weeks after induction chemotherapy and after completion of chemoradiotherapy (CRT). Tumour volumetry, MRI tumour regression grade (mrTRG), T and N categories, circumferential resection margin (CRM) status and extramural vascular invasion identified by MRI (mrEMVI) were evaluated. RESULTS: A total of 133 randomized patients were analysed. Median follow-up was 41·4 (95 per cent c.i. 36·6 to 45·2) months. Thirty-one patients (23·3 per cent) developed tumour recurrence. In univariable analysis, mrEMVI at baseline was the only prognostic factor associated with poorer outcome (P = 0·015). After induction chemotherapy, a larger tumour volume on MRI (P = 0·019), tumour volume regression of 60 per cent or less (P = 0·002), involvement of the CRM (P = 0·037), mrEMVI (P = 0·026) and a poor mrTRG (P = 0·023) were associated with poor outcome. After completion of CRT, the absence of complete response on MRI (P = 0·004), mrEMVI (P = 0·038) and a poor mrTRG (P = 0·005) were associated with shorter disease-free survival. A final multivariable model including all significant variables (baseline, after induction, after CRT) revealed that Eastern Cooperative Oncology Group performance status (P = 0·011), sphincter involvement (P = 0·009), mrEMVI at baseline (P = 0·002) and early tumour volume regression of 60 per cent or less after induction (P = 0·007) were associated with relapse. CONCLUSION: Baseline and early post-treatment MRI parameters are associated with prognosis in LARC. Future preoperative treatment should stratify treatment according to baseline mrEMVI status and early tumour volume regression.

ANTECEDENTES: El tratamiento neoadyuvante personalizado del cáncer de recto localmente avanzado (locally advanced rectal cancer, LARC) puede mejorar los resultados. El objetivo de este estudio fue determinar factores pronósticos precoces mediante RMN para estratificar el tratamiento neoadyuvante en pacientes con LARC. MÉTODOS: Todos los pacientes de un eensayo prospectivo de fase II, multicéntrico y aleatorizado (GRECCAR4-NCT01333709) se incluyeron en este estudio y se les realizó una RMN antes del tratamiento, 4 semanas después de la quimioterapia de inducción y después de completar la quimiorradioterapia (chemoradiation, CRT). Se evaluó la volumetría tumoral, el grado de regresión tumoral mediante RMN (MRI Tumor Regression Grade, mrTRG), la estadificación T, la estadificación N, el estado del margen de resección circunferencial (circumferential resection margin, CRM) y la presencia de invasión extramural vascular en la RMN (extramural vascular invasion, mrEMVI). RESULTADOS: Se analizaron 133 pacientes aleatorizados. La mediana de seguimiento fue de 41,4 meses (i.c. del 95%: 36,6-45,2). En 31 pacientes (23%) se diagnosticó una recidiva. En el análisis univariado de la situación basal, mrEMVI fue el único factor pronóstico asociado con un peor resultado (P = 0,0152). Después de la quimioterapia de inducción, un volumen tumoral más alto en la RMN (P = 0,019), una regresión del volumen tumoral ≤ 60% (P = 0,002), la afectación del CRM (P = 0,037), mrEMVI (P = 0,026) y un grado escaso mrTRG (P = 0,023) se asociaron con un mal resultado. Después de completar la CRT, la ausencia de respuesta completa en la RMN (P = 0,004), la presencia de mrEMVI (P = 0,04) y una insuficiente mrTRG (P = 0,005) se asociaron con una supervivencia libre de enfermedad más corta. En el modelo multivariable final en el que se incluyeron todas las variables significativas (basales, postinducción, post-CRT), el estado de ECOG (P = 0,011), la afectación esfinteriana (P = 0,009), la presencia de EMVI al inicio (P = 0,002) y una regresión precoz del volumen tumoral ≤ 60% después de la inducción (P = 0,007) se asociaron con una recidiva. CONCLUSIÓN: Los parámetros basales y post-tratamiento precoces de la RMN se asocian con el pronóstico en el LARC. La estrategia terapéutica preoperatoria futura deberá estratificar el tratamiento de acuerdo con la presencia de EMVI al inicio y la regresión precoz del volumen tumoral.

MRI-based score to predict surgical difficulty in patients with rectal cancer.

BACKGROUND: Rectal cancer surgery is technically challenging and depends on many factors. This study evaluated the ability of clinical and anatomical factors to predict surgical difficulty in total mesorectal excision. METHODS: Consecutive patients who underwent total mesorectal excision for locally advanced rectal cancer in a laparoscopic, robotic or open procedure after neoadjuvant treatment, between 2005 and 2014, were included in this retrospective study. Preoperative clinical and MRI data were studied to develop a surgical difficulty grade. RESULTS: In total, 164 patients with a median age of 61 (range 26-86) years were considered to be at low risk (143, 87·2 per cent) or high risk (21, 12·8 per cent) of surgical difficulty. In multivariable analysis, BMI at least 30 kg/m2 (P = 0·021), coloanal anastomosis (versus colorectal) (P = 0·034), intertuberous distance less than 10·1 cm (P = 0·041) and mesorectal fat area exceeding 20·7 cm2 (P = 0·051) were associated with greater surgical difficulty. A four-item score (ranging from 0 to 4), with each item (BMI, type of surgery, intertuberous distance and mesorectal fat area) scored 0 (absence) or 1 (presence), is proposed. Patients can be considered at high risk of a difficult or challenging operation if they have a score of 3 or more. CONCLUSION: This simple morphometric score may assist surgical decision-making and comparative study by defining operative difficulty before surgery.

SAR user guide to the rectal MR synoptic report (primary staging).

Rectal MR is the key diagnostic exam at initial presentation for rectal cancer patients. It is the primary determinant in establishing clinical stage for the patient and greatly impacts the clinical decision-making process. Consequently, structured reporting for MR is critically important to ensure that all required information is provided to the clinical care team. The SAR initial staging reporting template has been constructed to address these important items, including locoregional extent and factors impacting the surgical approach and management of the patient. Potential outputs to each item are defined, requiring the radiologist to commit to a result. This provides essential information to the surgeon or oncologist to make specific treatment deisions for the patient. The SAR Initial Staging MR reporting template has now been officially adopted by the NAPRC (National Accreditation Program for Rectal Cancer) under the American College of Surgery. With the recent revisions to the reporting template, this user guide has been revamped to improve its practicality and support to the radiologist to complete the structured report. Each line item of the report is supplemented with clinical perspectives, images, and illustrations to help the radiologist understand the potential implications for a given finding. Common errors and pitfalls to avoid are highlighted. Ideally, rectal MR interpretation should not occur in a vacuum but in the context of a multi-disciplinary tumor board to ensure that healthcare providers use common terminology and share a solid understanding of the strengths and weaknesses of MR.

Radiomics and radiogenomics in ovarian cancer: a literature review.

Ovarian cancer remains one of the most lethal gynecological cancers in the world despite extensive progress in the areas of chemotherapy and surgery. Many studies have postulated that this is because of the profound heterogeneity that underpins response to therapy and prognosis. Standard imaging evaluation using CT or MRI does not take into account this tumoral heterogeneity especially in advanced stages with peritoneal carcinomatosis. As such, newly emergent fields in the assessment of tumor heterogeneity have been proposed using radiomics to evaluate the whole tumor burden heterogeneity as opposed to single biopsy sampling. This review provides an overview of radiomics, radiogenomics, and proteomics and examines the use of these newly emergent fields in assessing tumor heterogeneity and its implications in ovarian cancer.

Ovarian cancer: An update on imaging in the era of radiomics.

Tumor heterogeneity in ovarian cancer has been reported at the histological and genetic levels and is associated with adverse clinical outcomes. Tumor evaluation using standard computed tomography or magnetic resonance imaging techniques does not account for the intra- or inter-tumoral heterogeneity in advanced ovarian cancer with peritoneal carcinomatosis. As such, computational approaches in assessing tumor heterogeneity have been proposed using radiomics and radiogenomics in order to analyze the whole tumor heterogeneity as opposed to single biopsy sampling. As part of radiomics, texture analysis, which includes the extraction of multiple data from images has been proposed recently to evaluate advanced ovarian tumor heterogeneity. In this short review, we explain the basics of radiomics, how to perform texture analysis, and its applications to ovarian cancer imaging.

How to differentiate uterine leiomyosarcoma from leiomyoma with imaging.

Uterine leiomyomas, the most frequent benign myomatous tumors of the uterus, often cannot be distinguished from malignant uterine leiomyosarcomas using clinical criteria. Furthermore, imaging differentiation between both entities is frequently challenging due to their potential overlapping features. Because a suspected leiomyoma is often managed conservatively or with minimally invasive treatments, the misdiagnosis of leiomyosarcoma for a benign leiomyoma could potentially result in significant treatment delays, therefore increasing morbidity and mortality. In this review, we provide an overview of the differences between leiomyoma and leiomyosarcoma, mainly focusing on imaging characteristics, but also briefly touching upon their demographic, histopathological and clinical differences. The main indications and limitations of available cross-sectional imaging techniques are discussed, including ultrasound, computed tomography, magnetic resonance imaging (MRI) and positron emission tomography/computed tomography. A particular emphasis is placed on the review of specific MRI features that may allow distinction between leiomyomas and leiomyosarcomas according to the most recent evidence in the literature. The potential contribution of texture analysis is also discussed. In order to help guide-imaging diagnosis, we provide an MRI-based diagnostic algorithm which takes into account morphological and functional features, both individually and in combination, in an attempt to optimize radiologic differentiation of leiomyomas from leiomyosarcomas.

[Diffusion-weighted MRI in sporadic Creutzfeldt-Jakob disease]. / Imagerie de diffusion et maladie de Creutzfeldt-Jakob sporadique.

Conventional MRI with T1, T2 and FLAIR sequences has an important role for the diagnosis of Creutzfeldt-Jakob disease, but the usual examination does not exclude the disease. The objective of this study is to report on the role of diffusion-weighted imaging (DWI) in the diagnostic strategy. From 2002 to 2006, four patients with a suspected diagnosis of sporadic Creutzfeldt-Jakob disease, which was retrospectively confirmed, underwent DWI. In all patients, MRI demonstrated high-signal intensities on FLAIR sequences and on spin-echo T2-weighted MRI, with restricted diffusion of caudate and lenticular nuclei. In one patient, DWI revealed cortical high-signal intensities that were not visualized on either FLAIR or T2-weighted MRI. In two other patients, MRI showed restricted thalamic diffusion, which is a classic sign of the new variant of the disease. Thus, thalamic involvement can be found in the sporadic form of the disease. It can be revealed on DWI and by apparent diffusion coefficient (ADC) mapping or detected only by ADC measurement.

Cystic pancreatic lesions: From increased diagnosis rate to new dilemmas.

Cystic pancreatic lesions vary from benign to malignant entities and are increasingly detected on cross-sectional imaging. Knowledge of the imaging appearances of cystic pancreatic lesions may help radiologists in their diagnostic reporting and management. In this review, we discuss the morphologic classification of these lesions based on a diagnostic algorithm as well as the management of these lesions.

Routine postoperative upper gastrointestinal fluoroscopy after laparoscopic sleeve gastrectomy: Is there still a utility?

PURPOSE: To assess the performance of routine esophagogastric transit studies (OGT) performed between day 2 (D2) and day 4 (D4) following sleeve gastrectomy for the diagnosis of gastric fistula. PATIENTS AND METHODS: Single center study including 736 patients undergoing surgery for sleeve gastrectomy including 32 of whom developed gastric fistula. Seven hundred and twenty OGT on D2 and 86 abdominal and pelvic CT scans were performed to investigate for a fistula and whether or not a blood collection was present. Sensitivity, specificity, positive and negative predictive values, Youden index (YI) and dosimetry were calculated for both investigations. RESULTS: The sensitivity and specificity of OGT for the diagnosis of fistula were 7% and 98% respectively with a PPV of 18%, an NPV of 96% and YI of 0.06. The mean DSP was 5500µGy.m(2). Sensitivity, specificity, positive and negative predictive values and Youden index for CT were 55%, 100%, 100%, 81%, 0.55, respectively for the presence of a fistula; and 96%, 86%, 78%, 98%, 0.83 for the presence of a non-blood collection and; 100%, 86%, 78%, 100%, 0.86 for the presence of a non-blood collection and/or fistula. The mean DLP was 3700 mGy.cm. CONCLUSION: Because of its very poor sensitivity for the diagnosis of gastric fistula, the OGT on D2 needs to be reconsidered. CT performed on clinical suspicion appears to be a better diagnostic tool.

Utility of reassessment after neoadjuvant therapy and difficulties in interpretation.

We describe the main tools for MR assessment of the response of rectal cancer tumors after chemotherapy, before surgery. In locally advanced cases of rectal and lower rectal cancer, MR is useful in allowing the treatment strategy to be adjusted, enabling conservative surgery to be performed if the patient responds well. The different types of response (fibrous, desmoplastic and colloid), their appearances and difficulties in MR interpretation are described. We describe the features and performance of MR after neoadjuvant therapy for T and N staging, assessment of circumferential resection margin and diffusion weighted imaging. Quantitative (change in tumor volume) and qualitative (grade of tumor response) MR assessment can distinguish good responders from poor responders.

[Imaging of the postoperative knee: normal and pathologic findings]. / Le genou opéré, aspect normal et complications.

Surgical management of lesions of the knee has exponentially increased over the last several years. MRI plays a major role in postoperative follow-up and evaluation of patients with residual symptoms. Familiarity with the different surgical procedures and potential complications and knowledge of normal and abnormal postoperative MRI findings are essential for evaluation of the postoperative knee. The main purpose of this article is to review the postoperative imaging features of ligaments, menisci and cartilage of the knee joint since these MRI features may lead the surgeon to consider repeat surgery.