A Unified Framework for Brain Segmentation in MR Images.

Brain MRI segmentation is an important issue for discovering the brain structure and diagnosis of subtle anatomical changes in different brain diseases. However, due to several artifacts brain tissue segmentation remains a challenging task. The aim of this paper is to improve the automatic segmentation of brain into gray matter, white matter, and cerebrospinal fluid in magnetic resonance images (MRI). We proposed an automatic hybrid image segmentation method that integrates the modified statistical expectation-maximization (EM) method and the spatial information combined with support vector machine (SVM). The combined method has more accurate results than what can be achieved with its individual techniques that is demonstrated through experiments on both real data and simulated images. Experiments are carried out on both synthetic and real MRI. The results of proposed technique are evaluated against manual segmentation results and other methods based on real T1-weighted scans from Internet Brain Segmentation Repository (IBSR) and simulated images from BrainWeb. The Kappa index is calculated to assess the performance of the proposed framework relative to the ground truth and expert segmentations. The results demonstrate that the proposed combined method has satisfactory results on both simulated MRI and real brain datasets.

Combined HER2 analysis of biopsies and surgical specimens to optimize detection of trastuzumab-eligible patients in eso-gastric adenocarcinoma: a GERCOR study.

BACKGROUND: HER2 is overexpressed in 10 to 20% of gastro-esophageal adenocarcinoma (GE-ADK), and is a target for trastuzumab in metastatic patients. We conducted a study to compare HER2 expression between diagnostic biopsies (DBs) and surgical specimens (SSs) of GE-ADK, and to determine the influence of non-trastuzumab containing neoadjuvant chemotherapy (NAC) on this expression. PATIENTS AND METHODS: Pathological specimens from biopsies of 228 patients operated on between 2004 and 2011 were collected. Two cohorts treated (n = 141) or not (n = 87) with a NAC were constituted. Two blind independent pathological HER2 analyses on DB and on SS were carried out using immunohistochemistry (IHC) and colorimetric in situ hybridization (CISH). HER-2 overexpression (HER2+) was defined by a score 3+ in IHC, or 2+ with a positive CISH test, according to the specific HER2 scoring guidelines for GE-ADK. RESULTS: Paired HER2 status could be determined for 218 out of the 228 patients (95.6%). HER2+ rates were 13.3% on DB (29/218) and 14.7% on SS (32/218). HER2+ tumors were mainly cardial or esophageal adenocarcinomas, with a well-differentiated, intestinal histological type. HER2 status differed between DB and SS in 6% of cases. When DB analyses were added to SS analyses, the relative increase in HER2+ cases was 13.5% (17.1% for patients with NAC and 23.5% for patients with histological response to NAC, versus 7.1% for patients without NAC, P = 0.4, NS). Differences between DB and SS HER2 expression could be explained by intratumoral heterogeneity and by a HER2 expression decrease in SS after NAC in responding patients possibly due to a higher chemosensitivity of HER2-positive clones. CONCLUSION: The determination of HER2 status on DB provides results that complete those obtained with SS. Combining the analysis of DB and of SS enables to optimize the selection of trastuzumab-eligible patients in case of metastatic relapse, and particularly in previously NAC-responding patients.

Panitumumab combined with irinotecan for patients with KRAS wild-type metastatic colorectal cancer refractory to standard chemotherapy: a GERCOR efficacy, tolerance, and translational molecular study.

BACKGROUND: The purpose of this study was to evaluate the combination of panitumumab and irinotecan in patients with KRAS wild-type metastatic colorectal cancer refractory to standard chemotherapy (oxaliplatin, fluoropyrimidines-irinotecan and bevacizumab). PATIENTS AND METHODS: KRAS status was first determined locally but subsequent validation of KRAS status and additional screenings (rare KRAS, NRAS, BRAF mutations and EGFR copy number) were centrally assessed. Patients received panitumumab (6 mg/kg) and irinotecan (180 mg/m²) every 2 weeks. RESULTS: Sixty-five eligible patients were analyzed. The objective response rate (ORR) was 29.2% [95% confidence interval (95% CI) 18.2-40.3]. Median progression-free and overall survivals were 5.5 and 9.7 months, respectively. Most frequent grade 3/4 toxic effects were skin 32.3%, diarrhea 15.4% and neutropenia 12.3%. Tissue samples were available for 60 patients. For the confirmed KRAS wild-type population codon 12 or 13 mutation (n = 54), ORR was 35.2% (95% CI 22.4.1-47.9). Thirteen patients had a NRAS, a BRAF or a rare KRAS mutation, and no tumor response was observed in this subgroup when compared with 46.3% (95% CI 31.1-61.6) ORR in the subgroup of 41 patients with no identified mutation. CONCLUSION: Panitumumab and irinotecan is an active third-line regimen in a well-defined population based on biomarkers. ClinicalTrials.gov Identifier NCT00655499.

Prognostic impact of microsatellite instability in colorectal cancer patients treated with adjuvant FOLFOX.

BACKGROUND: Colorectal cancer (CRC) patients whose tumours have microsatellite instability (MSI) do not benefit from adjuvant 5-fluorouracil. However, the predictive value of MSI is not known for FOLFOX, now recommended in adjuvant setting. PATIENTS AND METHODS: MSI phenotype was assessed by the pentaplex method. Three-year relapse and disease-free survival (DFS) of patients treated for CRC with FOLFOX 4 in an adjuvant setting were compared according to MSI phenotype. RESULTS: A total of 105 patients (19 MSI, 86 microsatellite stable, MSS) were included. Stage II patients more frequently exhibited MSI (58%) than MSS (21%); (p=0.002). Patients with MSI relapsed significantly less than those with MSS (10.5% vs. 35.0%; p=0.04). DFS was similar for MSI and MSS (p=0.1). In univariate analysis, stage (p=0.0006) and MSI status (p=0.017) were significant predictors of DFS. CONCLUSION: MSI status was associated with significantly fewer relapses and a better prognosis. FOLFOX4 did not alter survival of patients with MSI and can be administered to them.

Phase II Study of Biweekly Pemetrexed Plus Irinotecan as Second-Line Therapy for Metastatic Colorectal Cancer.

Background. This open-label, single-arm, two-stage, Phase II study investigated the efficacy and safety of bi-weekly pemetrexed combined with irinotecan, in patients with metastatic colorectal cancer (mCRC), after first-line chemotherapy using FOLFOX regimen. Patients and methods. Patients received pemetrexed 400 mg/m(2) as a 10-minute intravenous infusion (with vitamin supplementation) followed by irinotecan 180 mg/m(2) as a 90-minute infusion on day 1 of a 14-day cycle, for a maximum of 12 cycles. The primary endpoint was response rate (RR; H(0) /= 20%, alpha = 0.05, power = 90%). Secondary endpoints were duration of response, progression-free survival (PFS), overall survival (OS), and toxicities. Results. Partial response was observed in six out of 44 patients enrolled in the study (RR = 13.6%). The median PFS and OS were 4.0 and 13.9 months, respectively. The most common grade 3-4 toxicities were fatigue: 20.5% of patients, neutropenia: 18.6%, diarrhea: 13.6%, elevated transaminases: 9.5%, anemia: 9.3%, and vomiting: 6.8%. Conclusion. Pemetrexed plus irinotecan administered every two weeks is an active and well-tolerated regimen in mCRC patients pretreated with FOLFOX regimen. However, this regimen does not seem to provide clinically relevant advantage over historical data of a classical FOLFIRI regimen.

Reliability analysis of the rank transform for stereo matching.

The rank transform is a nonparametric technique which has been recently proposed for the stereo matching problem. The motivation behind its application to this problem is its invariance to certain types of image distortion and noise, as well as its amenability to real-time implementation. This paper derives one constraint which must be satisfied for a correct match. This has been termed the rank constraint. Experimental work has shown that this constraint is capable of resolving ambiguous matches, thereby improving matching reliability. A novel matching algorithm incorporating the rank constraint has also been proposed. This modified algorithm consistently resulted in an increased percentage of correct matches, for all test imagery used. Furthermore, the rank constraint has been used to devise a method of identifying regions of an image where the rank transform, and hence matching outcome, is more susceptible to noise. Experimental results have shown that the errors predicted using this technique are consistent with the actual errors which result when images are corrupted with noise. Such a method could be used to identify matches which are likely to be incorrect and/or provide a measure of confidence in a match.

A structural-description-based vision system for automatic object recognition.

This paper presents the results of the integration of a proposed part-segmentation-based vision system. The first stage of this system extracts the contour of the object using a hybrid first- and second-order differential edge detector. The object defined by its contour is then decomposed into its constituent parts using the part segmentation algorithm given by Bennamoun (1994). These parts are then isolated and modeled with 2D superquadrics. The parameters of the models are obtained by the minimization of a best-fit cost function. The object is then represented by its structural description which is a set of data structures whose predicates represent the constituent parts of the object and whose arguments represent the spatial relationship between these parts. This representation allows the recognition of objects independently of their positions, orientations, or sizes. It is also insensitive to objects with partially missing parts. In this paper, examples illustrating the acquired images of objects, the extraction of their contours, the isolation of the parts, and their fitting with 2D superquadrics are reported. The reconstruction of objects from their structural description is illustrated and improvements are suggested.

Dual modulation of 5-fluorouracil with folinic acid and hydroxyurea in metastatic colorectal cancer.

Leucovorin and 5-fluorouracil (5-FU) can be further modulated with hydroxyurea. Sixty-eight patients with advanced colorectal cancer received every 2 weeks hydroxyurea per os 1.5 g to 2 g days -1, 1, and 2; leucovorin 200 mg/m2 iv over 2 hours started at least 1 hour after hydroxyurea and per os 100 mg/m2 12 hours later, on days 1 and 2; 5-FU, bolus 400 mg/m2 during leucovorin infusion and 24 hours continuous infusion 600 mg/m2, repeated on days 1 and 2. Two complete responses (7%), 8 partial responses (30%), 12 no change (44%), and 5 progressions (19%) were observed among 31 nonpreviously treated patients. Four partial response (11%), 15 no change (43%), and 16 progressions (46%) were observed among 37 pretreated patients. Nineteen were treated after progression on the same regimen without oral leucovorin and hydroxyurea, 1 achieved PR and 10 showed no change. Among them, 6 experienced response or stabilization of longer duration than with previous treatment. Twelve-month survival was 61% in non-pretreated and 43% in pretreated patients as of the start of chemotherapy. Toxicity was mild with nausea in 46%, diarrhea in 37%, and mucositis in 36%. The first-line response rate is in the range of leucovorin and 5-FU alone. Some pretreated patients benefited from this regimen.

Bi-weekly 2-day schedule of high-dose folinic acid, 5-fluorouracil bolus and infusion in pretreated advanced epithelial ovarian cancer: a phase II study.

Twenty patients with documented progression after two or three cisplatin-based regimens for advanced epithelial ovarian carcinoma were treated with high-dose folinic acid (200 mg/m2), 5-fluorouracil bolus (400 mg/m2) and continuous infusion (600 mg/m2) for two consecutive days every two weeks. One clinically complete and two partial responses were observed in 16 evaluable patients, with 5 remaining stable. Median survival was 9 months. Toxicity was mild. This combination achieved a 19% (95% confidence interval 4%-46%) response rate in heavily pretreated cisplatin-resistant patients.