Comprehensive image quality comparison of conventional and new flat panel detectors under bedside chest radiography beam conditions.

Recently, a novel wireless flat-panel detector with auto-exposure control has become available. This study aimed to elucidate the potential advantages of the new detector over conventional detectors through a comprehensive analysis of the physical image quality characteristics. Measurements were conducted on two models: new (720C) and conventional (710C) versions; this assessment was performed by assuming the beam quality for bedside chest radiography, utilizing a portable device for X-ray exposure.

Evaluation of the measurement accuracy and uncertainty of a solid-state detector under diagnostic x-ray beam conditions.

Objective: An accurate measurement of x-ray beams is expected to reduce the uncertainties associated with estimating radiation risk to patients in clinical settings. To perform assessment tasks based on the readings of a solid-state detector (SSD) using semiconductor technology, the characteristics of the detector should be elucidated. In this study, we evaluated the measurement accuracy of a new SSD under diagnostic x-ray beam conditions in terms of air kerma, tube voltage, and half-value layer (HVL).

An image quality assessment index based on image features and keypoints for X-ray CT images.

Optimization tasks in diagnostic radiological imaging require objective quantitative metrics that correlate with the subjective perception of observers. However, although one such metric, the structural similarity index (SSIM), is popular, it has limitations across various aspects in its application to medical images. In this study, we introduce a novel image quality evaluation approach based on keypoints and their associated unique image feature values, focusing on developing a framework to address the need for robustness and interpretability that are lacking in conventional methodologies.

Auto-evaluation of skull radiograph accuracy using unsupervised anomaly detection.

Background: Radiography plays an important role in medical care, and accurate positioning is essential for providing optimal quality images. Radiographs with insufficient diagnostic value are rejected, and retakes are required. However, determining the suitability of retaking radiographs is a qualitative evaluation.

Analysis of the precision of modulation transfer function measurements with a circular edge: influence of object circularity.

Purpose: To measure the modulation transfer function (MTF) using a circular edge, we generate a synthesized edge spread function from multiple profiles radiating from the center, assuming that the circular object is perfectly round. Therefore, this study aimed to quantify the influence of the shape change of the circular edge on the measurement precision of the MTF.

Approach: To examine this relationship, we generated simulated images with intentionally distorted circular edges and analyzed the correlation between circularity and the calculated MTF.

Simulation Analysis on the Performance of a Circular-Edge Technique in Measurements of the Modulation Transfer Function.

The modulation transfer function (MTF) plays an important role in characterizing medical imaging systems. For such characterization, the circular-edge technique has become a prevalent task-based methodology. When determining the MTF with complicated task-based measurements, error factors must be well understood to properly interpret the results.

Properties of the SSIM metric in medical image assessment: correspondence between measurements and the spatial frequency spectrum.

In radiological imaging, the acquisition of the required diagnostic image quality under optimized conditions is important. Although techniques based on structural similarity (SSIM) have been investigated, concerns have been raised regarding their application to medical images. This study aims to clarify the properties of SSIM as an image quality index in medical images, focusing on digital radiography and verifying the correspondence between the evaluation results obtained by SSIM and the frequency spectrum.

Quantification of the Intrinsic T1 and T2 of Heschl's Gyri with MR Fingerprinting.

Purpose: The human primary auditory cortex is located in the Heschl's gyrus (HG). To assess the intrinsic MR property in the gray matter of the HG (GM-HG) with T1 and T2 values using a commercially available MR fingerprinting (MRF) technique.

Methods: The subjects were 10 healthy volunteers (with 20 HGs; mean age, 31.

Assessment of Uncertainty Depending on Various Conditions in Modulation Transfer Function Calculation Using the Edge Method.

In medical X-ray imaging, to perform optimal operations, it is essential for the user to understand whether a required image quality level which depends on a diagnostic task can be achieved with the imaging system used. This study focuses on the effects of noise on the modulation transfer function (MTF) using the edge method, the most widely used to evaluate the task dependence property. The purpose is to verify the uncertainty of the MTF value at each spatial frequency and examine the conditions under which the accuracy is ensured.

Cerebral ventriculomegaly in myotonic dystrophy type 1: normal pressure hydrocephalus-like appearances on magnetic resonance imaging.

Background: Cerebral ventriculomegaly is an abnormal feature characteristic of myotonic dystrophy type 1 (DM1). This retrospective study investigated the morphologic changes accompanied by ventriculomegaly in DM1 on brain MRI.

Methods: One hundred and twelve adult patients with DM1 and 50 sex- and age-matched controls were assessed.

Characterization of anti-scatter grids via a modulation transfer function improvement factor using an edge device.

In optimizing the imaging conditions, changes in image quality due to scattered radiation are important evaluation targets. This study focuses on the evaluation of the image quality improvement characteristics obtained using anti-scatter grids in digital x-ray imaging, and proposes a frequency-dependent modulation transfer function (MTF) improvement factor,MIFG(u),as a new evaluation index. Accordingly, the purpose of this study is to clarify the validity and the usefulness of this proposed index in the performance evaluation of grids.

Effectiveness of Cytological Diagnosis with Outer Cannula Washing Solution for Computed Tomography-Guided Needle Biopsy.

Rationale And Objectives: We evaluated the availability of cytological diagnosis with outer cannula washing solution (C-OCWS) as a clinical diagnostic tool for computed tomography (CT)-guided needle biopsy.

Materials And Methods: We retrospectively assessed 109 consecutive patients (71 males, 38 females; median age 68 years), who underwent CT-guided needle biopsy. In all patients, the specimens sampled by the inner needle were used for histological diagnosis, and those taken from the outer cannula were rinsed with 0.

EXPOSURE DOSE INDEX BASED ON NOISE FACTOR ANALYSIS IN DIGITAL MAMMOGRAPHY: VERIFICATION USING DIRECT-TYPE FLAT-PANEL DETECTOR SYSTEM.

In this study, the development of a reasonable index of optimized exposure dose is attempted. Using a direct-type flat-panel system, noise factors contained in the image are analyzed based on the relative standard deviation method, and it is verified that the proposed index conforms with the appropriate standards regarding minimum exposure dose. The findings indicate that Poisson noise is dominant in the general clinical dose range; this noise fraction formed 90% of the total noise in the system considered in this study.

Visualization of blurring process due to analog components in a digital radiography system using a simple method.

To obtain useful medical X-ray images for diagnosis, it is necessary to accurately evaluate the characteristics and fully understand the features of the system to determine the imaging target and conditions. This study describes the performance of a digital radiography (DR) system in detail and proposes a method for characterizing the blurring process due to the presence of analog components in an imaging system. Our method does not involve any specialized technique, such as a simulation that requires long computing time on a high-performance computer.

The effects of scattered radiation from a semitransparent edge on MTF measurement: verification of several factors by Monte Carlo simulation.

Accurate evaluation of image quality not only characterizes system performance but also allows quantitative understanding of various image quality factors and the resulting image quality changes. The presampled modulation transfer function (MTF) can be useful in determining system resolution characteristics and response reduction caused by certain image quality factors. Although many studies have been conducted to accurately measure the MTF, there is still ample room for investigation of factors that affect the measured MTF for a task-based assessment using a semitransparent edge.