Lung nodule localization and size estimation on chest tomosynthesis.

Purpose: We aim to investigate the localization, visibility, and measurement of lung nodules in digital chest tomosynthesis (DTS).

Approach: Computed tomography (CT), maximum intensity projections (CT-MIP) (transaxial versus coronal orientation), and computer-aided detection (CAD) were used as location reference, and inter- and intra-observer agreement regarding lung nodule size was assessed. Five radiologists analyzed DTS and CT images from 24 participants with lung , focusing on lung nodule localization, visibility, and measurement on DTS.

Breathing motion compensation in chest tomosynthesis: evaluation of the effect on image quality and presence of artifacts.

Purpose: Chest tomosynthesis (CTS) has a relatively longer acquisition time compared with chest X-ray, which may increase the risk of motion artifacts in the reconstructed images. Motion artifacts induced by breathing motion adversely impact the image quality. This study aims to reduce these artifacts by excluding projection images identified with breathing motion prior to the reconstruction of section images and to assess if motion compensation improves overall image quality.

Evaluation of deep-learning image reconstruction for chest CT examinations at two different dose levels.

Aims: The aims of the present study were to, for both a full-dose protocol and an ultra-low dose (ULD) protocol, compare the image quality of chest CT examinations reconstructed using TrueFidelity (Standard kernel) with corresponding examinations reconstructed using ASIR-V (Lung kernel) and to evaluate if post-processing using an edge-enhancement filter affects the noise level, spatial resolution and subjective image quality of clinical images reconstructed using TrueFidelity.

Methods: A total of 25 patients were examined with both a full-dose protocol and an ULD protocol using a GE Revolution APEX CT system (GE Healthcare, Milwaukee, USA). Three different reconstructions were included in the study: ASIR-V 40%, DLIR-H, and DLIR-H with additional post-processing using an edge-enhancement filter (DLIR-H + E2).

Poor inter-observer agreement in anatomical classifications of infrapopliteal arterial disease due to mandatory selection of only one target artery.

Background: Established anatomical classifications of infrapopliteal arterial lesion severity are based on assessment of only one target artery, not including all infrapopliteal arteries although multivessel revascularization is common.

Purpose: To investigate the reproducibility of one of these classifications and a new aggregated score.

Material And Methods: A total of 68 patients undergoing endovascular infrapopliteal revascularization at Sahlgrenska University Hospital during 2008-2016 were included.

AUTOMATED QC FOR INTERVENTIONAL SYSTEMS AND MAMMOGRAPHY SYSTEMS.

Quality control (QC) of X-ray equipment is an important task for patient safety. Periodic QC should not take long to perform, especially in a stressful clinical environment where downtime should be minimised. DOSESTAT-QC® is a new quick QC software with automatic image analysis that has been developed into a quality-assured and user-friendly tool for daily use.

VIEWDEX 3.0-RECENT DEVELOPMENT OF A SOFTWARE APPLICATION FACILITATING ASSESSMENT OF IMAGE QUALITY AND OBSERVER PERFORMANCE.

ViewDEX (Viewer for Digital Evaluation of X-ray Images) is an image viewer compatible with Digital Imaging and Communications in Medicine (DICOM) that has been especially designed to facilitate image perception and observer performance studies within medical imaging. The software was first released in 2004 and since then a continuous development has been ongoing. One of the major drawbacks of previous versions of ViewDEX has been that they have lacked functionality enabling the possibility to evaluate multiple images and/or image stacks simultaneously.

Comparison of Magnetic Resonance Angiography and Digital Subtraction Angiography for the Assessment of Infrapopliteal Arterial Occlusive Lesions, Based on the TASC II Classification Criteria.

This paper aimed to study the agreement and repeatability, both intra- and interobserver, of infrapopliteal lesion assessment with magnetic resonance angiography (MRA), using the TransAtlantic Inter-Society Consensus (TASC) II criteria, with perioperative digital subtraction angiography (DSA) as a reference. Sixty-eight patients with an MRA preceding an endovascular infrapopliteal revascularization were included. Preoperative MRAs and perioperative DSAs were evaluated in random order by three independent observers using the TASC II classification.

The Effect of Dose Reduction on Overall Image Quality in Clinical Chest Tomosynthesis.

Rationale And Objectives: To evaluate the effect of reduction in effective dose on the reproduction of anatomical structures in chest tomosynthesis (CTS).

Materials And Methods: Twenty-four CTS examinations acquired at exposure settings resulting in an effective dose of 0.12 mSv for an average sized patient were included in the study.

Detection of Pulmonary Nodule Growth with Chest Tomosynthesis: A Human Observer Study Using Simulated Nodules.

Rationale And Objectives: Chest tomosynthesis has been suggested as a suitable alternative to CT for follow-up of pulmonary nodules. The aim of the present study was to investigate the possibility of detecting pulmonary nodule growth using chest tomosynthesis.

Materials And Methods: Simulated nodules with volumes of approximately 100 mm and 300 mm as well as additional versions with increasing volumes were created.

Evaluation of a corrected implementation of a method of simulating pulmonary nodules in chest tomosynthesis.

Background A method of simulating pulmonary nodules in tomosynthesis images has previously been developed and evaluated. An unknown feature of a rounding function included in the computer code was later found to introduce an artifact, affecting simulated nodules in low-signal regions of the images. The computer code has now been corrected.

EFFECT OF RADIATION DOSE LEVEL ON ACCURACY AND PRECISION OF MANUAL SIZE MEASUREMENTS IN CHEST TOMOSYNTHESIS EVALUATED USING SIMULATED PULMONARY NODULES.

The aim of the present study was to investigate the dependency of the accuracy and precision of nodule diameter measurements on the radiation dose level in chest tomosynthesis. Artificial ellipsoid-shaped nodules with known dimensions were inserted in clinical chest tomosynthesis images. Noise was added to the images in order to simulate radiation dose levels corresponding to effective doses for a standard-sized patient of 0.

THORACIC SPINE IMAGING: A COMPARISON BETWEEN RADIOGRAPHY AND TOMOSYNTHESIS USING VISUAL GRADING CHARACTERISTICS.

The aim of the present study was to evaluate digital tomosynthesis (DTS) in thoracic spine imaging, comparing the reproduction of anatomical structures with that achieved using digital radiography (DR). In a prospective visual grading study, 23 patients referred in 2014 for elective radiographic examination of the thoracic spine were examined using lateral DR and DTS. The DR image and the DTS section images were read in random order by four radiologists, evaluating the ability of the modalities to present a clear reproduction of nine specific relevant structures of the thoracic vertebrae 3, 6 and 9 (T3, T6 and T9).

VIEWDEX: A STATUS REPORT.

ViewDEX (Viewer for Digital Evaluation of X-ray images) is an image viewer and task manager suitable for research and optimisation tasks in medical imaging. The software has undergone continuous development during more than a decade and has during this time period been used in numerous studies. ViewDEX is DICOM compatible, and the features of the interface (tasks, image handling and functionality) are general and flexible.

INFLUENCE OF THE IN-PLANE ARTEFACT IN CHEST TOMOSYNTHESIS ON PULMONARY NODULE SIZE MEASUREMENTS.

The aim of the present study was to investigate how the in-plane artefact present in the scan direction around structures in tomosynthesis images should be managed when measuring the size of nodules in chest tomosynthesis images in order to achieve acceptable measurement accuracy. Data from measurements, performed by radiologists, of the longest diameter of artificial nodules inserted in chest tomosynthesis images were used. The association between the measurement error and the direction of the longest nodule diameter, relative to the scan direction, was evaluated using the Kendall rank correlation coefficient.

EFFECTIVE DOSE TO PATIENTS FROM THORACIC SPINE EXAMINATIONS WITH TOMOSYNTHESIS.

The purposes of the present work were to calculate the average effective dose to patients from lateral tomosynthesis examinations of the thoracic spine, compare the results with the corresponding conventional examination and to determine a conversion factor between dose-area product (DAP) and effective dose for the tomosynthesis examination. Thoracic spine examinations from 17 patients were included in the study. The registered DAP and information about the field size for each projection radiograph were, together with patient height and mass, used to calculate the effective dose for each projection radiograph.

RETROSPECTIVE ESTIMATION OF PATIENT DOSE-AREA PRODUCT IN THORACIC SPINE TOMOSYNTHESIS PERFORMED USING VOLUMERAD.

The aim of this study was to evaluate the use of a recently developed method of retrospectively estimating the patient dose-area product (DAP) of a chest tomosynthesis examination, performed using VolumeRAD, in thoracic spine tomosynthesis and to determine the necessary field-size correction factor. Digital imaging and communications in medicine (DICOM) data for the projection radiographs acquired during a thoracic spine tomosynthesis examination were retrieved directly from the modality for 17 patients. Using the previously developed method, an estimated DAP for the tomosynthesis examination was determined from DICOM data in the scout image.

Estimating effective dose from 3D imaging with interventional fluoroscopy systems using limited exposure data.

Background: Estimations of the effective dose from three-dimensional (3D) rotational imaging with interventional fluoroscopy systems are hampered by the fact that not all systems provide individual exposure values for each projection image included in the examination.

Purpose: To investigate the error in resulting effective dose introduced by not using individual exposure values for each projection image in the dose calculations for 3D rotational imaging with interventional fluoroscopy systems.

Material And Methods: An interventional fluoroscopy system was used to acquire images of two anthropomorphic phantoms.

Image quality dependency on system configuration and tube voltage in chest tomosynthesis—a visual grading study using an anthropomorphic chest phantom.

Purpose: To investigate the potential benefit of increasing the dose per projection image in chest tomosynthesis, performed at the current standard dose level, by reducing the angular range covered or the projection image density and to evaluate the influence of the tube voltage on the image quality.

Methods: An anthropomorphic chest phantom was imaged using nine different projection image configurations and ten different tube voltages with the GE VolumeRAD tomosynthesis system. The resulting image sets were representative of being acquired at the same total effective dose.

Evaluation of accuracy and precision of manual size measurements in chest tomosynthesis using simulated pulmonary nodules.

Rationale And Objectives: To investigate the accuracy and precision of pulmonary nodule size measurements on chest tomosynthesis images.

Materials And Methods: Artificial ellipsoid-shaped nodules with known sizes were inserted in clinical chest tomosynthesis images. The volume of the nodules corresponded to that of a sphere with a diameter of 4.

A simple method to retrospectively estimate patient dose-area product for chest tomosynthesis examinations performed using VolumeRAD.

Purpose: The purpose of the present work was to develop and validate a method of retrospectively estimating the dose-area product (DAP) of a chest tomosynthesis examination performed using the VolumeRAD system (GE Healthcare, Chalfont St. Giles, UK) from digital imaging and communications in medicine (DICOM) data available in the scout image.

Methods: DICOM data were retrieved for 20 patients undergoing chest tomosynthesis using VolumeRAD.

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis.

Objective: To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels.

Methods: Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70% of the default setting effective dose (0.

Pulmonary nodule size evaluation with chest tomosynthesis.

Purpose: To evaluate intra- and interobserver variability, as well as agreement for nodule size measurements on chest tomosynthesis and computed tomographic (CT) images.

Materials And Methods: The Regional Ethical Review Board approved this study, and all participants gave written informed consent. Thirty-six segmented nodules in 20 patients were included in the study.

Evaluation of an improved method of simulating lung nodules in chest tomosynthesis.

Background: Simulated pathology is a valuable complement to clinical images in studies aiming at evaluating an imaging technique. In order for a study using simulated pathology to be valid, it is important that the simulated pathology in a realistic way reflect the characteristics of real pathology.

Purpose: To perform a thorough evaluation of a nodule simulation method for chest tomosynthesis, comparing the detection rate and appearance of the artificial nodules with those of real nodules in an observer performance experiment.

Learning aspects and potential pitfalls regarding detection of pulmonary nodules in chest tomosynthesis and proposed related quality criteria.

Background: In chest tomosynthesis, low-dose projections collected over a limited angular range are used for reconstruction of an arbitrary number of section images of the chest, resulting in a moderately increased radiation dose compared to chest radiography.

Purpose: To investigate the effects of learning with feedback on the detection of pulmonary nodules for observers with varying experience of chest tomosynthesis, to identify pitfalls regarding detection of pulmonary nodules, and present suggestions for how to avoid them, and to adapt the European quality criteria for chest radiography and computed tomography (CT) to chest tomosynthesis.

Material And Methods: Six observers analyzed tomosynthesis cases for presence of nodules in a jackknife alternative free-response receiver-operating characteristics (JAFROC) study.