Search results for "lesion"

Lesion of areas 17/18/19: effects on the cat's performance in a binary detection task

1988

The ability of two cats to discriminate between two geometrical outline patterns in the presence of superimposed Gaussian visual noise — i.e. in a binary detection task — was tested before and after bilateral removal of cortical areas 17, 18 and 19. The detection probability PD was measured as a function of the signal-to-noise ratio. After a lesion of areas 17, 18 and 19 both cats were unable to carry out the discrimination tasks. Their detection performance dropped to chance level, but after an extensive phase of retraining (3 months) they regained the ability to discriminate visual patterns. It was thus possible to obtain detection curves and to determine a measure of a performance which …

Semi-automatic Brain Lesion Segmentation in Gamma Knife Treatments Using an Unsupervised Fuzzy C-Means Clustering Technique

2016

MR Imaging is being increasingly used in radiation treatment planning as well as for staging and assessing tumor response. Leksell Gamma Knife (R) is a device for stereotactic neuro-radiosurgery to deal with inaccessible or insufficiently treated lesions with traditional surgery or radiotherapy. The target to be treated with radiation beams is currently contoured through slice-by-slice manual segmentation on MR images. This procedure is time consuming and operator-dependent. Segmentation result repeatability may be ensured only by using automatic/semi-automatic methods with the clinicians supporting the planning phase. In this paper a semi-automatic segmentation method, based on an unsuperv…

Steerable wavelet transform for atlas based retinal lesion segmentation

2013

International audience; Computer aided diagnosis and follow up can help in prevention and treatment of diabetes and its related complications. Screening of diabetes related disease in the eyes is done by a special low cost fundus camera. A follow up of the patients visiting at di fferent time intervals for screening brings us to the problem of image analysis for change detection and its cost per patient. It is very likely that human annotations for the lesions may be erroneous and often time consuming. Since the ethnic background plays a signi cant role in retinal pigment epithelium, visibility of the choroidal vasculature and overall retinal luminance in patients and retinal images, an eth…

Partial volume correction for volume estimation of liver metastases and lymph nodes in CT scans using spatial subdivision

2010

In oncological therapy monitoring, the estimation of tumor growth from consecutive CT scans is an important aspect in deciding whether the given treatment is adequate for the patient. This can be done by measuring and comparing the volume of a lesion in the scans based on a segmentation. However, simply counting the voxels within the segmentation mask can lead to significant differences in the volume, if the lesion has been segmented slightly differently by various readers or in different scans, due to the limited spatial resolution of CT and due to partial volume effects. We present a novel algorithm for measuring the volume of liver metastases and lymph nodes which considers partial volum…

State of the art and clinical recommendations in periapical implant lesions. 9th Mozo-Grau Ticare Conference in Quintanilla, Spain.

2016

This manuscript summarizes the statements and clinical recommendations in periapical implant lesions, as per the state of the art and expert opinion agreement among the participants in the 9th Mozo-Grau Conference 2016 held in Quintanilla (Valladolid, Spain). The current status of the concept, frequency, etiology, diagnosis, clinical classification, surgical procedure and prognosis are described. If following implant placement localized pain develops in the periapical area, with or without radiographic changes, the diagnosis of periapical implant lesion should be suspected. It is important to monitor the condition in order to identify any change in its evolution. Radiological changes in the…

Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: A comparison study.

2014

Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically …

Advanced imaging of the gastrointestinal tract: research vs. clinical tools?

2009

Diagnostic endoscopy has moved forward considerably in the recent years. Still, three major needs have to be satisfied: endoscopy should be able to detect a lesion, characterize the lesion, and then its nature should be confirmed. These steps should ideally translate into an immediate therapeutic decision.High definition endoscopy has optimized our endoscopic view onto the mucosa and can be combined with digital surface enhancement modalities. Chromoendoscopy still holds a place to detect especially flat lesions in high-risk patients such as ulcerative colitis. Digital chromoendoscopy techniques such as narrow band imaging, i-scan, or Fuji intelligent chromo endoscopy offer new possibilitie…

Role of Contrast-enhanced Ultrasound in the Characterization of Incidentally Discovered Focal Liver Lesions

2007

Usure civili e sovrapposizione antinomica delle discipline

2013

Mammographic images segmentation based on chaotic map clustering algorithm

2013

Background: This work investigates the applicability of a novel clustering approach to the segmentation of mammographic digital images. The chaotic map clustering algorithm is used to group together similar subsets of image pixels resulting in a medically meaningful partition of the mammography. Methods: The image is divided into pixels subsets characterized by a set of conveniently chosen features and each of the corresponding points in the feature space is associated to a map. A mutual coupling strength between the maps depending on the associated distance between feature space points is subsequently introduced. On the system of maps, the simulated evolution through chaotic dynamics leads…