MRI Assessment of Changes in Tumor Vascularization during Neoadjuvant Anti-Angiogenic Treatment in Locally Advanced Breast Cancer Patients.

Anti-VEGF (vascular endothelial growth factor) treatment improves response rates, but not progression-free or overall survival in advanced breast cancer. It has been suggested that subgroups of patients may benefit from this treatment; however, the effects of adding anti-VEGF treatment to a standard chemotherapy regimen in breast cancer patients are not well studied. Understanding the effects of the anti-vascular treatment on tumor vasculature may provide a selection of patients that can benefit.

A Prospective Study of High Dose-Rate Brachytherapy or Stereotactic Body Radiotherapy of Intra-Prostatic Recurrence: Toxicity and Long Term Clinical Outcome.

Background: Up to half of patients with localized prostate cancer experience biochemical relapse within 10 years after definitive radiotherapy. The aim of this prospective study was to investigate the toxicity, dose to the organs at risk (OARs), and efficacy of dose-intensified focal salvage radiotherapy.

Methods And Material: Thirty-three patients (median age 68.

Handling missing MRI sequences in deep learning segmentation of brain metastases: a multicenter study.

The purpose of this study was to assess the clinical value of a deep learning (DL) model for automatic detection and segmentation of brain metastases, in which a neural network is trained on four distinct MRI sequences using an input-level dropout layer, thus simulating the scenario of missing MRI sequences by training on the full set and all possible subsets of the input data. This retrospective, multicenter study, evaluated 165 patients with brain metastases. The proposed input-level dropout (ILD) model was trained on multisequence MRI from 100 patients and validated/tested on 10/55 patients, in which the test set was missing one of the four MRI sequences used for training.

Noise dependency in vascular parameters from combined gradient-echo and spin-echo DSC MRI.

Dynamic susceptibility contrast (DSC) imaging is a widely used technique for assessment of cerebral blood volume (CBV). With combined gradient-echo and spin-echo DSC techniques, measures of the underlying vessel size and vessel architecture can be obtained from the vessel size index (VSI) and vortex area, respectively. However, how noise, and specifically the contrast-to-noise ratio (CNR), affect the estimations of these parameters has largely been overlooked.

Responses in the diffusivity and vascular function of the irradiated normal brain are seen up until 18 months following SRS of brain metastases.

Background: MRI may provide insights into longitudinal responses in the diffusivity and vascular function of the irradiated normal-appearing brain following stereotactic radiosurgery (SRS) of brain metastases.

Methods: Forty patients with brain metastases from non-small cell lung cancer ( = 26) and malignant melanoma ( = 14) received SRS (15-25 Gy). Longitudinal MRI was performed pre-SRS and at 3, 6, 9, 12, and 18 months post-SRS.

Brain metastases with poor vascular function are susceptible to pseudoprogression after stereotactic radiation surgery.

Purpose: This study aimed to investigate the hemodynamic status of cerebral metastases prior to and after stereotactic radiation surgery (SRS) and to identify the vascular characteristics that are associated with the development of pseudoprogression from radiation-induced damage with and without a radionecrotic component.

Methods And Materials: Twenty-four patients with 29 metastases from non-small cell lung cancer or malignant melanoma received SRS with dose of 15 Gy to 25 Gy. Magnetic resonance imaging (MRI) scans were acquired prior to SRS, every 3 months during the first year after SRS, and every 6 months thereafter.

Dynamic (18) F-FDG PET for Assessment of Tumor Physiology in Two Breast Carcinoma Xenografts.

Purpose: To compare dynamic 2-deoxy-2-[(18) F]fluoro-D-glucose positron emission tomography ((18) F-FDG PET) parameters in two selected human breast cancer xenografts and to evaluate associations with immunohistochemistry and histology.

Procedures: Dynamic (18) F-FDG PET of luminal-like MAS98.06 and basal-like MAS98.

Associations between tumor vascularization assessed by in vivo DCE-MRI and the presence of disseminated tumor cells in bone marrow in breast cancer patients at the time of diagnosis.

Purpose: To explore possible associations between in vivo pharmacokinetic dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters and the presence of disseminated tumor cells (DTCs) in bone marrow in breast cancer patients at the time of diagnosis.

Materials And Methods: Thirty-seven women with breast cancer (stage T2-4N0-1M0) were included. Patients were classified as DTC+ if one or more DTCs were detected by immunocytochemistry.

Sculpting of DNA at abasic sites by DNA glycosylase homolog mag2.

Modifications and loss of bases are frequent types of DNA lesions, often handled by the base excision repair (BER) pathway. BER is initiated by DNA glycosylases, generating abasic (AP) sites that are subsequently cleaved by AP endonucleases, which further pass on nicked DNA to downstream DNA polymerases and ligases. The coordinated handover of cytotoxic intermediates between different BER enzymes is most likely facilitated by the DNA conformation.

Quantitative analysis of diffusion-weighted magnetic resonance imaging in malignant breast lesions using different b value combinations.

Objectives: To explore how apparent diffusion coefficients (ADCs) in malignant breast lesions are affected by selection of b values in the monoexponential model and to compare ADCs with diffusion coefficients (Ds) obtained from the biexponential model.

Methods: Twenty-four women (mean age 51.3 years) with locally advanced breast cancer were included in this study.

AP endonuclease independent repair of abasic sites in Schizosaccharomyces pombe.

Abasic (AP) sites are formed spontaneously and are inevitably intermediates during base excision repair of DNA base damages. AP sites are both mutagenic and cytotoxic and key enzymes for their removal are AP endonucleases. However, AP endonuclease independent repair initiated by DNA glycosylases performing β,δ-elimination cleavage of the AP sites has been described in mammalian cells.

Schizosaccharomyces pombe encodes a mutated AP endonuclease 1.

Mutagenic and cytotoxic apurinic/apyrimidinic (AP) sites are among the most frequent lesions in DNA. Repair of AP sites is initiated by AP endonucleases and most organisms possess two or more of these enzymes. Saccharomyces cerevisiae has AP endonuclease 1 (Apn1) as the major enzymatic activity with AP endonuclease 2 (Apn2) being an important backup.

Preclinical dynamic 18F-FDG PET - tumor characterization and radiotherapy response assessment by kinetic compartment analysis.

Background: Non-invasive visualization of tumor biological and molecular processes of importance to diagnosis and treatment response is likely to be critical in individualized cancer therapy. Since conventional static (18)F-FDG PET with calculation of the semi-quantitative parameter standardized uptake value (SUV) may be subject to many sources of variability, we here present an approach of quantifying the (18)F-FDG uptake by analytic two-tissue compartment modeling, extracting kinetic tumor parameters from dynamic (18)F-FDG PET. Further, we evaluate the potential of such parameters in radiotherapy response assessment.

Diffusion-weighted magnetic resonance imaging for pretreatment prediction and monitoring of treatment response of patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy.

Background: For patients with locally advanced breast cancer (LABC) undergoing neoadjuvant chemotherapy (NACT), the European Guidelines for Breast Imaging recommends magnetic resonance imaging (MRI) to be performed before start of NACT, when half of the NACT has been administered and prior to surgery. This is the first study addressing the value of flow-insensitive apparent diffusion coefficients (ADCs) obtained from diffusion-weighted (DW) MRI at the recommended time points for pretreatment prediction and monitoring of treatment response.

Materials And Methods: Twenty-five LABC patients were included in this prospective study.

Collaborative work and medical talk: opportunities for learning through knowledge sharing.

Teleconsultations provide new opportunities for learning in medical settings. This study explores the conditions under which learning among physicians takes place. The empirical context is 47 real-time video conferences carried out to examine collaborative work and the medical talk involved.

Teleconsultation - collaborative work and opportunities for learning across organizational boundaries.

Over a period of five months we observed teleconsultations between general practitioners (GPs) in community care and specialists in hospitals in two Norwegian health regions (A and B). In total, 47 teleconsultations between GPs and specialists were recorded. In region A, teleconsultations were organized when needed to discuss specific medical problems.

Success and failure in Web-based medical collaboration.

A Web-based collaboration tool was developed for ophthalmologists, called Øyenet. A feasibility study was performed in 2000. The system was ready to use in 2001, but the usage of the system was disappointing, compared to the enthusiasm expressed in the feasibility study.