Comparison of tomosynthesis methods used with digital mammography.

Rationale And Objectives: The authors performed this study to investigate the potential applicability of tomosynthesis to digital mammography. Four methods of tomosynthesis-tuned aperture computed tomography (TACT)-backprojection, TACT-iterative restoration, iterative reconstruction with expectation maximization, and Bayesian smoothing-were compared to planar mammography and analyzed in terms of their contrast-detail characteristics. Specific comparisons between the tomosynthesis methods were not attempted in this study.

Breast imaging using an amorphous silicon-based full-field digital mammographic system: stability of a clinical prototype.

An amorphous silicon-based full-breast imager for digital mammography was evaluated for detector stability over a period of 1 year. This imager uses a structured CsI:TI scintillator coupled to an amorphous silicon layer with a 100-micron pixel pitch and read out by special purpose electronics. The stability of the system was characterized using the following quantifiable metrics: conversion factor (mean number of electrons generated per incident x-ray), presampling modulation transfer function (MTF), detector linearity and sensitivity, detector signal-to-noise ratio (SNR), and American College of Radiology (ACR) accreditation phantom scores.

Mammographic imaging with a small format CCD-based digital cassette: physical characteristics of a clinical system.

The physical characteristics of a clinical charge coupled device (CCD)-based imager (Senovision, GE Medical Systems, Milwaukee, WI) for small-field digital mammography have been investigated. The imager employs a MinR 2000 (Eastman Kodak Company, Rochester, NY) scintillator coupled by a 1:1 optical fiber to a front-illuminated 61 x 61 mm CCD operating at a pixel pitch of 30 microns. Objective criteria such as modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), and noise equivalent quanta (NEQ) were employed for this evaluation.

Percutaneous delivery of a heparin-impregnated collagen stent-graft in a porcine model of atherosclerotic disease.

Rationale And Objectives: To develop collagen stent-grafts impregnated with heparin to improve the biocompatibility of endovascular stents and to design a percutaneous delivery system for graft deployment in a swine model.

Methods: Heparin-impregnated collagen stent-grafts were deployed, and follow-up angiograms were obtained every 15 minutes for 90 minutes to assess acute thromboses and again at 2 and 4 weeks afterward to assess patency. If stenosis or occlusion was detected at the 2-week evaluation, guidewire passage across the lesion was attempted and angioplasty was performed.

Full breast digital mammography with an amorphous silicon-based flat panel detector: physical characteristics of a clinical prototype.

The physical characteristics of a clinical prototype amorphous silicon-based flat panel imager for full-breast digital mammography have been investigated. The imager employs a thin thallium doped CsI scintillator on an amorphous silicon matrix of detector elements with a pixel pitch of 100 microm. Objective criteria such as modulation transfer function (MTF), noise power spectrum, detective quantum efficiency (DQE), and noise equivalent quanta were employed for this evaluation.

Uterine artery embolization for the treatment of uterine leiomyomata midterm results.

Introduction: The authors review their midterm experience with uterine artery embolization for the treatment of uterine fibroids.

Materials And Methods: Sixty patients were referred for permanent polyvinyl alcohol (PVA) foam particle uterine artery embolization during an 18-month period. Detailed clinical follow-up and ultrasound follow-up were obtained.

Small peripancreatic veins: improved assessment in pancreatic cancer patients using thin-section pancreatic phase helical CT.

Objective: Recent studies have shown evaluation of the small peripancreatic veins to have potential in improving pancreatic cancer staging. This study was performed to determine the effectiveness of thin-section pancreatic phase helical CT images in visualizing these veins.

Materials And Methods: Seventy-two patients (30 with pancreatic adenocarcinoma and 42 with no pancreatic disease) underwent dual-phase helical CT with thin-section pancreatic phase acquisition (40-70 sec after i.

Preliminary experience with uterine artery embolization for uterine fibroids.

Purpose: To evaluate the potential usefulness of transcatheter uterine artery embolization as a treatment for fibroid-related vaginal bleeding and pelvic pain refractory to hormonal therapy and myomectomy.

Materials And Methods: Eleven patients (aged 27-55 years; mean, 44.2 years; none desiring future pregnancy) with refractory vaginal bleeding and/or chronic pelvic pain related to uterine leiomyomata underwent uterine artery embolization with use of polyvinyl alcohol (PVA) particles.

Uterine artery embolization: an underused method of controlling pelvic hemorrhage.

Transcatheter arterial embolization has recently emerged as a highly effective percutaneous technique for controlling acute and chronic genital bleeding in a wide variety of obstetric and gynecologic disorders. Benefits for the patient and health care system have included low complication rates, avoidance of surgical risks, fertility preservation, and shorter hospitalizations. In this article the current indications for pelvic embolotherapy, types of embolotherapy, technical considerations, immediate success rates, causes of failure, complications, and outcome expectations are discussed.

Contrast Study of CdZnTe Detectors for Digital Mammography.

Experiments have been performed with the aim of optimizing the image quality parameters of CdZnTe detectors for digital mammography. A geometrical breast phantom has been designed, and the dependence of the contrast resolution of a planar CdZnTe detector on the phantom thickness has been experimentally determined. Specifically, the detected signal and noise contributions were measured and related to phantom thickness.

Cd1-xZnx Te Detectors for Digital X-Ray Chest Imaging.

Radiographic studies with the aim of optimizing the imaging potential of Cd1-xZnxTe detectors for digital chest radiography have been performed. A geometrical chest phantom has been designed, and the dependence of both the signal-to-noise ratio and contrast resolution of a planar Cd1-xZnxTe detector on the phantom thickness has been experimentally determined. Specifically, the detected signal and noise contributions were measured and related to phantom thickness.

Signal Dependence on Irradiation Geometry of Cd1-xZnxTe Detectors for Digital X-Ray Imaging.

CdZnTe is one of the most promising semiconductor material in the field of digital X-ray imaging, and may be operated at room temperature. To improve the detector characteristics, ternary systems such as Cd1-xZnxTe were grown by the high pressure Bridgman (HPG) technique. The signal performance characteristics of quasi-resistive Cd1-xZnxTe semiconductor detectors, was studied at different directions of irradiation, within the X-ray diagnostic energy range.

Electric Field Dependence on Charge Collection of CdZnTe X-Ray Detectors.

In this study, the electric field dependence on the charge collection process of CdZnTe detectors, at different x-ray tube settings, within the x-ray diagnostic energy range, is investigated. In addition, the detector contrast at different applied bias voltages and x-ray tube settings have been experimentally determined. The experimental results suggest that an efficient charge collection process is obtained by increasing the applied bias voltage.

Optimization of Cd1-xZnxTe Detectors for Digital Radiography.

In this study, measurements of the electrical and detection parameters of the Cd1-xZnxTe detectors, within the x-ray diagnostic energy range, have been performed with the aim of optimizing the image quality parameters of these solid-state-ionization detectors. Namely, the leakage current and system capacitance of the x-ray imaging system have been measured as they relate to signal parameters. Similarly, the detected signal and noise contributions were measured and related to the radiation exposure and tube current setting.

Two-phase helical CT for pancreatic tumors: pancreatic versus hepatic phase enhancement of tumor, pancreas, and vascular structures.

Purpose: To quantitatively evaluate and validate a two-phase helical computed tomographic (CT) protocol for evaluation of pancreatic tumors.

Materials And Methods: Twenty-seven patients with pathologically proved pancreatic adenocarcinomas prospectively underwent two-phase CT examination with helical acquisition during the pancreatic phase (40-70 seconds after infusion of intravenous contrast material at 3 mL/sec) and the hepatic phase (70-100 seconds after infusion). Mean CT attenuation values of tumor, bordering pancreas, and all major peripancreatic vessels were obtained for both time intervals.

Line spread function study of kinestatic charge detectors operating at high gas pressures.

A systematic study of the line spread function (LSF) in the drift direction of a high-pressure ionization chamber for x-ray detection and imaging is presented. Experimental results, obtained by operating a KCD krypton-filled detector at pressures up to 60 atm and constant electric field-to-gas pressure ratio, indicate that the width of the LSF increases with the drift distance and decreases with increasing pressure, both effects being quite large. The hypothesis of this paper is that, at sufficiently high pressures, formation of clusters of molecular ions with a unique or narrowed mobility distribution take place by means of energy exchange mechanisms.

Ultrastructural characteristics of the spleen in hairy cell leukemia.

Eighteen spleens derived from patients with hairy cell leukemia (HCL) were analyzed by correlative scanning and transmission electron microscopy. In 15 of the cases, the white pulp areas were markedly decreased or absent when compared to normal spleens, although few hairy cells were observed within this region. In only one case did the white pulp appear normal.

Mechanism of interferon action in hairy cell leukemia: a model of effective cancer biotherapy.

Hairy cell leukemia (HCL) is one of the few malignancies for which alpha-interferon (IFN alpha) is considered effective first-line therapy. However, the mechanisms of action of this agent in vivo have been the subject of much debate; in particular, the issue of whether clinical improvement in IFN-alpha-treated HCL patients is dependent upon enhancement of host defenses or upon direct actions of IFN alpha upon the hairy cell remains unresolved. In this review, we examine the evidence supporting both lines of argument and synthesize this information within the framework of clinical studies of IFN alpha in HCL, the purpose being to determine which proposed mechanisms of IFN alpha action are indeed effective in vivo.

HDS: Establishment of a New Cell Line from a Hairy Cell Leukemia Patient with Resistance to Alpha-Interferon Therapy.

A new cell line, designated "HDS", was established in a suspension culture derived from the peripheral blood of a patient with hairy cell leukemia (HCL) who developed clinical resistance to alpha-interferon (aIFN) therapy. The patient exhibited a clinical picture characteristic of HCL, including splenomegaly, cytopenias, and tartrate-resistant acid phosphatase (TRAP)-positive "hairy" cells in blood and marrow. Chromosomal studies revealed that the cultured cells possess the chromosomal abnormality +12.

Killing of Burkitt-lymphoma-derived Daudi cells by ultraviolet-inactivated vaccinia virus.

Interaction of active and UV-inactivated vaccinia virus at high multiplicity caused cytological changes and inhibition in cellular protein and DNA synthesis, thus arresting the multiplication of Burkitt-lymphoma-derived Daudi cells and eventually killing the cells. Adsorption to the cells but the lack of penetration was evident by immunofluorescence, electron microscopy and [3H]thymidine-labeled virus incorporation. Viral DNA synthesis or virus replication was not demonstrated.

Relationship between heparin binding characteristics and ability of human spermatozoa to penetrate hamster ova.

Heparin binding site affinity and density on human spermatozoa were compared between fertile and infertile men with normal or abnormal results in the zona-free hamster ova-sperm penetration assay (SPA). A portion of fresh semen from fertile donors and potentially infertile men was processed through the SPA while the remainder of the ejaculate was used to quantitate heparin binding on spermatozoa. Saturation binding assays with [3H]heparin (15-375 nM) were analysed for 3 groups of men: (1) infertile patients with abnormal SPA results, (2) infertile patients with normal SPA results and (3) fertile donors.