Hybrid multi-layer Deep CNN/Aggregator feature for image classification

Deep Convolutional Neural Networks (DCNN) have established a remarkable performance benchmark in the field of image classification, displacing classical approaches based on hand-tailored aggregations of local descriptors. Yet DCNNs impose high computational burdens both at training and at testing time, and training them requires collecting and annotating large amounts of training data. Supervised adaptation methods have been proposed in the literature that partially re-learn a transferred DCNN structure from a new target dataset. Yet these require expensive bounding-box annotations and are still computationally expensive to learn. In this paper, we address these shortcomings of DCNN adaptation schemes by proposing a hybrid approach that combines conventional, unsupervised aggregators such as Bag-of-Words (BoW), with the DCNN pipeline by treating the output of intermediate layers as densely extracted local descriptors. We test a variant of our approach that uses only intermediate DCNN layers on the standard PASCAL VOC 2007 dataset and show performance significantly higher than the standard BoW model and comparable to Fisher vector aggregation but with a feature that is 150 times smaller. A second variant of our approach that includes the fully connected DCNN layers significantly outperforms Fisher vector schemes and performs comparably to DCNN approaches adapted to Pascal VOC 2007, yet at only a small fraction of the training and testing cost.Comment: Accepted in ICASSP 2015 conference, 5 pages including reference, 4 figures and 2 table

SoDeep: a Sorting Deep net to learn ranking loss surrogates

International audienceSeveral tasks in machine learning are evaluated using non-differentiable metrics such as mean average precision or Spearman correlation. However, their non-differentiability prevents from using them as objective functions in a learning framework. Surrogate and relaxation methods exist but tend to be specific to a given metric. In the present work, we introduce a new method to learn approximations of such non-differentiable objective functions. Our approach is based on a deep architecture that approximates the sorting of arbitrary sets of scores. It is trained virtually for free using synthetic data. This sorting deep (SoDeep) net can then be combined in a plug-and-play manner with existing deep architectures. We demonstrate the interest of our approach in three different tasks that require ranking: Cross-modal text-image retrieval, multi-label image classification and visual memorability ranking. Our approach yields very competitive results on these three tasks, which validates the merit and the flexibility of SoDeep as a proxy for sorting operation in ranking-based losses

Vacuolar hepatopathies in dogs

Vacuolar hepatopathies include a heterogeneous group of so-called overloading hepatopathies. Their diagnosis is based on histological criteria, such as hepatocyte swelling resulting in cytomegaly with vacuolated and reticulated cytoplasm. Vacuolar hepatopathy is often idiopathic. Its development can be secondary to a simple reactive hepatopathy, and include numerous associated conditions. Endogenous or exogenous hypercorticism is the most common cause of vacuolar hepatopathy in dogs. The frequency and complications of idiopathic vacuolar hepatopathy in Scottish terriers suggest a breed and familial predisposition.Les hépatopathies vacuolaires désignent un groupe assez hétérogène d'hépatopathies dites de surcharge, dont le diagnostic repose sur des critères histologiques comme la ballonisation des hépatocytes, qui entraîne une cytomégalie, la vacuolisation et la réticulation de leur cytoplasme. Les hépatopathies vacuolaires sont souvent idiopathiques. Elles peuvent être le prolongement d'une simple hépatopathie réactive et de nombreuses affections peuvent s'associer à leur développement. Un hypercorticisme endogène ou exogène est la cause la plus fréquente d'hépatopathie vacuolaire chez le chien. Il existe chez le chien de race Scottish terrier une hépatopathie vacuolaire idiopathique dont la fréquence et les complications permettent d'envisager une prédisposition raciale et familiale

Radio-frequency tissue ablation of the liver: in vivo and ex vivo experiments with four different systems

The aim of this study was to test the efficacy of four different radio-frequency ablation (RFA) systems in normal hepatic parenchyma in large animals. The RFA was applied to pig livers in vivo and to calf livers ex vivo using the Radionics cluster needle, RITA starburst XL needle, Radiotherapeutics Le Veen 4.0 needle, and the Berchtold 14-G saline-perfused 15-mm active-tip needle based on constructor specifications. The volume of tissue coagulation from RF was calculated from measurements of the vertical diameter (Dv) and transverse diameter (Dt). Lesion shape was characterized using the ratio between Dt/Dv. Radiotherapeutics and RITA produced in vivo lesion volume of 42±10, 39±4cm3 with a reproducible spherical shape (Dt/Dv of 1.01±0.16 and 0.97±0.1, respectively). Radionics produced in vivo RF lesions volume of 29±11cm3 with an ovoid shape (Dt/Dv 0.88±0.09). The RF lesions with the Berchtold device could not be assessed in vivo as 5 of 8 animals died during treatment. Ex vivo RF lesions had similar volumes with each system; however, the Radiotherapeutics device produced more reproducible shaped lesions than the other systems. In our experimental study, we found no difference between expandable needle systems in vivo. Cooled needles produced slightly smaller and ovoid shape in vivo lesion

Interventional radiology in the management of complications after liver transplantation

The arrival of new surgical transplantation techniques, such as split living donor or auxiliary liver transplantation, have increased the incidence of vascular and biliary complications. The causes, symptoms, and diagnostic modalities of arterial, portal caval, and biliary complications are detailed. Interventional techniques, such as balloon angioplasty and stent placement in the arterial and portal tree, as well as biliary interventional techniques, are discusse

Multidetector CT enteroclysis: comparison of the reading performance for axial and coronal views

The purpose of this study was to compare the diagnostic performance of axial and coronal views in multidetector CT enteroclysis (MDCTE). We retrospectively evaluated 48 patients with pathological correlation investigated by MDCTE for small bowel disorders. After nasojejunal administration of 2l of 5% methylcellulose axial arterial and venous acquisition of MDCTE was followed by coronal reconstructions using equal slice thicknesses of 2.5mm with 2mm increments. Spatial resolution of both planes was evaluated by phantom. Three radiologists independently read axial and coronal images concerning 12 pathological features. The interobserver agreement and time of reading was calculated. Sensitivity and specificity resulted from comparison with histopathology (n=39) or follow-up (n=9). Phantom study revealed higher spatial resolution for axial than coronal views, whatever reconstruction interval was used. However, spatial frequency always remained high. Most pathological signs, such as bowel wall thickening (BWT), bowel wall enhancement (BWE) and intraperitoneal fluid (IPF), showed better interobserver agreement on axial than coronal views (BWT: 0.61 vs. 0.44; BWE: 0.56 vs. 0.5; IPF:0.53 vs. 0.43). The Wilcoxon signed-rank test revealed significantly higher sensitivity for axial than coronal views (P=0.0453); the time of reading was significantly shorter for the latter (P=0.0146). The diagnostic value of axial slices is superior to coronal reconstructions despite the reduced data volume and display of the physiological course of bowel loops on the coronal plan

Palliative Portal Vein Stent Placement in Malignant and Symptomatic Extrinsic Portal Vein Stenosis or Occlusion

This article evaluates the results of portal vein (PV) stent placement in patients with malignant extrinsic lesions stenosing or obstructing the PV and causing symptomatic PV hypertension (PVHT). Fourteen patients with bile duct cancer (n=7), pancreatic adenocarcinoma (n=4), or another cancer (n=3) underwent percutaneous transhepatic portal venous stent placement because of gastroesophageal or jejunal varices (n=9), ascites (n=7), and/or thrombocytopenia (n=2). Concurrent tumoral obstruction of the main bile duct was treated via the transhepatic route in the same session in four patients. Changes in portal venous pressure, complications, stent patency, and survival were evaluated. Mean±standard deviation (SD) gradient of portal venous pressure decreased significantly immediately after stent placement from 11.2mmHg±4.6 to 1.1mmHg±1.0 (P<0.00001). Three patients had minor complications, and one developed a liver abscess. During a mean±SD follow-up of 134.4±123.3days, portal stents remained patent in 11 patients (78.6%); stent occlusion occurred in 3 patients, 2 of whom had undergone previous major hepatectomy. After stent placement, PVHT symptoms were relieved in four (57.1%) of seven patients who died (mean survival, 97±71.2days), and relieved in six (85.7%) of seven patients still alive at the end of follow-up (mean follow-up, 171.7±153.5days). Stent placement in the PV is feasible and relatively safe. It helped to relieve PVHT symptoms in a single sessio

Detection of liver metastases under 2cm: comparison of different acquisition protocols in four row multidetector-CT (MDCT)

This study compared different acquisition protocols performance to detect small liver metastases (<2cm). Thirty consecutive patients with histologically proven hepatic metastases were explored by MDCT at the liver equilibrium phase by four successive acquisitions. We compared the following protocols (1-4): 5/30/1.5 (section thickness/table speed/pitch); 5/15/0.75; 5/11.25/0.75; and 2.5/15/1.5 with the same X-ray dose. The gold standard was based on patient radiological follow-up. Evolutive lesions were considered as true positive (TP). The described lesions, not found on the follow-up exams despite tumoral progression, were considered as false positive (FP). Stable lesions could not be considered as metastasis and were eliminated. One hundred and seventy-six lesions were detected: 61 TP and 91 FP. Twenty-four lesions were eliminated. The mean kappa values for protocols 1, 2, 3 and 4 were, respectively, 0.43, 0.68, 0.73 and 0.51 (0.61-0.80: substantial agreement) and the mean areas under the ROC curve were, respectively, 0.76, 0.87, 0.86 and 0.80. The results of protocols 2 and 3 were significantly superior to those of protocols 1 and 4. MDCT protocols using thin sections or an increased table speed are less efficient in detecting small metastase