A clinical validation study for the feasibility and reliability of three-dimensional ultrasound-ultrasound automatic image registration.

Purpose: The purpose of our study was to assess the feasibility and reliability of 3D ultrasound-ultrasound (US-US) automatic registration-based analysis of the hepatic vessel tree (VT) (3D VT-based automatic registration) in clinical applications.

Materials And Methods: A total of 70 pairs of 3D ultrasound data were acquired from the livers of 10 healthy volunteers enrolled in the study. An automatic registration method was applied to the acquired volumetric data pairs, and anatomic landmarks were picked by an experienced sonographer as 'ground truth'.

Tagged template deformation.

Model-based approaches are very popular for medical image segmentation as they carry useful prior information on the target structure. Among them, the implicit template deformation framework recently bridged the gap between the efficiency and flexibility of level-set region competition and the robustness of atlas deformation approaches. This paper generalizes this method by introducing the notion of tagged templates.

Registration of free-breathing 3D+t abdominal perfusion CT images via co-segmentation.

Dynamic contrast-enhanced computed tomography (DCE-CT) is a valuable imaging modality to assess tissues properties, particularly in tumours, by estimating pharmacokinetic parameters from the evolution of pixels intensities in 3D+t acquisitions. However, this requires a registration of the whole sequence of volumes, which is challenging especially when the patient breathes freely. In this paper, we propose a generic, fast and automatic method to address this problem.

Incorporating shape variability in image segmentation via implicit template deformation.

Implicit template deformation is a model-based segmentation framework that was successfully applied in several medical applications. In this paper, we propose a method to learn and use prior knowledge on shape variability in such framework. This shape prior is learnt via an original and dedicated process in which both an optimal template and principal modes of variations are estimated from a collection of shapes.

Semiautomatic volumetric tumor segmentation for hepatocellular carcinoma: comparison between C-arm cone beam computed tomography and MRI.

Rationale And Objectives: To evaluate the precision and reproducibility of a semiautomatic tumor segmentation software in measuring tumor volume of hepatocellular carcinoma (HCC) before the first transarterial chemo-embolization (TACE) on contrast-enhancement magnetic resonance imaging (CE-MRI) and intraprocedural dual-phase C-arm cone beam computed tomography (DP-CBCT) images.

Materials And Methods: Nineteen HCCs were targeted in 19 patients (one per patient) who underwent baseline diagnostic CE-MRI and an intraprocedural DP-CBCT. The images were obtained from CE-MRI (arterial phase of an intravenous contrast medium injection) and DP-CBCT (delayed phase of an intra-arterial contrast medium injection) before the actual embolization.

Automatic detection and segmentation of kidneys in 3D CT images using random forests.

Kidney segmentation in 3D CT images allows extracting useful information for nephrologists. For practical use in clinical routine, such an algorithm should be fast, automatic and robust to contrast-agent enhancement and fields of view. By combining and refining state-of-the-art techniques (random forests and template deformation), we demonstrate the possibility of building an algorithm that meets these requirements.

Real-time 3D image segmentation by user-constrained template deformation.

We describe an algorithm for 3D interactive image segmentation by non-rigid implicit template deformation, with two main original features. First, our formulation incorporates user input as inside/outside labeled points to drive the deformation and improve both robustness and accuracy. This yields inequality constraints, solved using an Augmented Lagrangian approach.

Joint co-segmentation and registration of 3D ultrasound images.

Contrast-enhanced ultrasound (CEUS) allows a visualization of the vascularization and complements the anatomical information provided by conventional ultrasound (US). However, these images are inherently subject to noise and shadows, which hinders standard segmentation algorithms. In this paper, we propose to use simultaneously the different information coming from 3D US and CEUS images to address the problem of kidney segmentation.

Direct quantification of cell-associated HIV DNA in isolated rectal and blood memory CD4 T cells revealed their similar and low infection levels in long-term treated HIV-infected patients.

To evaluate the contribution of CD4 T cells from blood and gut compartments to the HIV-1 reservoir, we directly quantified cell-associated HIV DNA in isolated rectal (R-) and peripheral blood (PB-) memory CD4 T cells from 11 successfully long-term treated patients. Proportion of activated (CD25(+); CD69(+); and HLA-DR(+)) and CCR5 expressing CD4 T cells were markedly higher in rectal tissue compared with blood. However, HIV-1 infection levels of R- and PB-memory CD4 T cells did not significantly differ (medians: 4000 and 2100 copies per million cells) after effective long-term viral control, suggesting that each of these 2 compartments does not contribute in a similar fashion to the total HIV reservoir.

Comparison of semi-automatic volumetric VX2 hepatic tumor segmentation from cone beam CT and multi-detector CT with histology in rabbit models.

Rationale And Objectives: The purpose of this study was to compare tumor volume in a VX2 rabbit model as calculated using semiautomatic tumor segmentation from C-arm cone-beam computed tomography (CBCT) and multidetector computed tomography (MDCT) to the actual tumor volume.

Materials And Methods: Twenty VX2 tumors in 20 adult male New Zealand rabbits (one tumor per rabbit) were imaged with CBCT (using an intra-arterial contrast medium injection) and MDCT (using an intravenous contrast injection). All tumor volumes were measured using semiautomatic three-dimensional volumetric segmentation software.

HIV-1 genome is often defective in PBMCs and rectal tissues after long-term HAART as a result of APOBEC3 editing and correlates with the size of reservoirs.

Objectives: Precise characterization of viruses present in reservoirs in long-term pretreated patients will be a major issue to consider in the context of viral eradication. We assessed the frequency of defective viruses present in cellular reservoirs.

Methods: Peripheral blood mononuclear cells (PBMCs) and rectal biopsy samples were compared between five patients on successful long-term highly active antiretroviral therapy (HAART) (>7 years without blips) and five untreated patients.

Comprehensive segmentation of cine cardiac MR images.

A typical Cardiac Magnetic Resonance (CMR) examination includes acquisition of a sequence of short-axis (SA) and long-axis (LA) images covering the cardiac cycle. Quantitative analysis of the heart function requires segmentation of the left ventricle (LV) SA images, while segmented LA views allow more accurate estimation of the basal slice and can be used for slice registration. Since manual segmentation of CMR images is very tedious and time-consuming, its automation is highly required.

Prevalence of anal cytologic abnormalities in a French referral population: a prospective study with special emphasis on HIV, HPV, and smoking.

Purpose: Studying anal cytology to detect intraepithelial neoplasia has been demonstrated to be useful in highly selected populations. This study was designed to determine the frequency of abnormal smears in a wide sample of patients consulting for anorectal symptoms.

Methods: An anal smear was proposed during each consultation during a three-month period.

Formalin application in the treatment of chronic radiation-induced hemorrhagic proctitis--an effective but not risk-free procedure: a prospective study of 33 patients.

Purpose: This prospective study evaluated the efficacy and safety of local formalin application in chronic refractory radiation-induced hemorrhagic proctitis.

Methods: All patients were treated under anesthesia by direct application of 4 percent formalin to the affected rectal areas.

Results: The study included 33 patients (17 women) and was conducted between January 1994 and December 2001.