K-Edge Imaging Using a Clinical Dual-Source Photon-Counting CT System.

Purpose: To evaluate the feasibility and performance of K-edge imaging of iodine (I) and gadolinium (Gd) on a clinically available photon-counting computed tomography (PCCT) system.

Methods: A dual-source clinical PCCT scanner with four energy thresholds (20, 55, 72, 90 keV) was used to scan phantoms containing pure and mixed solutions of I and Gd across multiple concentrations (1-10 mg/mL) and radiation doses (1-8 mGy). Multi-material decomposition was performed using a calibration-based, image-domain algorithm to generate material-specific maps.

Impact of Vessel Size, Dose Levels, and Body Habitus on Iodine Quantification in Cardiovascular Photon-Counting Computed Tomography.

Objectives: This study evaluates the performance of a clinical dual-source photon-counting computed tomography (PCCT) system in quantifying iodine within calcified vessels, using 3D-printed phantoms with vascular-like structures lined with calcium.

Methods: Parameters assessed include lumen diameters (4, 6, 8, 10, and 12 mm), phantom sizes (S: 20 × 20 cm, M: 25 × 25 cm, L: 30 × 40 cm), and iodine concentrations (2, 5, and 10 mg/mL). Scans were performed with a cardiac high-pitch acquisition protocol at radiation dose levels of 5 and 10 mGy to systematically evaluate iodine quantification accuracy and spectral imaging performance.

Efficient spectral data reduction for accurate iodine quantification in multi-energy CT.

This study proposes a spectral data reduction method for multi-channel computed tomography (CT) that optimizes material decomposition accuracy while minimizing data complexity. Spectral CT enables quantitative assessments by utilizing multiple spectral channels, yet the associated noise and computational demands can limit its clinical application. We introduce a weighting scheme that reduces acquired four spectral channels-derived from a dual-layer, rapid kVp-switching (kVp-S) CT setup-into two optimized input channels for material decomposition.

Simulated low-dose multi-detector computed tomography: spatial effects on surrogate parameters of bone strength at the proximal femur.

Unlabelled: This study investigated simulated tube current reduction and sparse sampling for low-dose computed tomography (CT) regarding volumetric bone mineral density (vBMD) and cortical bone thickness (Ct.Th) of the proximal femur. Sparse sampling with dose reductions of up to 90% may still allow extraction of bone strength parameters with clinically acceptable accuracy.

CT imaging of and therapy for inflammatory bowel disease low molecular weight dextran coated ceria nanoparticles.

Inflammatory bowel disease (IBD) affects approximately 3.1 million individuals in the U.S.

PixelPrint 4D : A 3D Printing Method of Fabricating Patient-Specific Deformable CT Phantoms for Respiratory Motion Applications.

Objectives: Respiratory motion poses a significant challenge for clinical workflows in diagnostic imaging and radiation therapy. Many technologies such as motion artifact reduction and tumor tracking have been developed to compensate for its effect. To assess these technologies, respiratory motion phantoms (RMPs) are required as preclinical testing environments, for instance, in computed tomography (CT).

Hybrid Spectral CT: Combining rapid kVp-switching and dual-layer detectors for high sensitivity iodine imaging.

Over the past two decades, spectral computed tomography (CT) has undergone significant advancements, particularly in the realm of diagnostic accuracy, prompting a surge in clinical studies. This research examines the development of a new hybrid spectral CT system that combines a clinical-grade rapid kVp-switching X-ray tube with a dual-layer detector, aiming to boost quantitative spectral imaging performance in different clinical applications. The performance of the system was evaluated using varying tube voltages, duty cycles, and rotation times to enhance spectral outcomes.

Long-term quantitative stability of a first-generation dual-source photon-counting CT.

The introduction of the first clinical photon-counting CT (PCCT) presents an opportunity to improve and expand quantitative imaging to new applications with its high spatial resolution and stellar quantitative capabilities. Despite this potential, PCCT employs a photon-counting detector that introduces unknowns including temporal stability that is critical to separating biological changes from scanner changes and variation in longitudinal studies. For the purpose of determining the temporal stability of a first-generation dual-source PCCT, a phantom was subjected to near-weekly scans across a two-year period, in both single-source and dual-source modes.

Quantitative metal artifact reduction algorithm for spectral CT thermometry.

Spectral CT thermometry can non-invasively monitor internal temperatures to reduce local tumor recurrences caused by insufficient heating/treatment of the tumor and its surrounding safety margin. For its clinical translation, the applied metal artifact reduction algorithm requires quantitative accuracy to ensure the accuracy of generated temperature maps. The newly developed Spectrally Obtained Needle Artifact Reduction (SONAR) algorithm leverages the known shape of the applicator and spectral CT's material decomposition capabilities to isolate the applicator in projections.

Spectral quantification in different lumen diameters for cardiovascular applications.

The first clinical dual-source photon-counting CT couples high spatial resolution with spectral imaging that is advantageous to imaging of small vessels, such as the coronary arteries, in cardiovascular disease. While both the high spatial resolution and quantification accuracy have been established in PCCT, the effect of lumen size on spectral quantification has not been evaluated. Phantoms with an internal tube diameter ranging from 4 to 12 mm were printed with calcium-based polylactic acid filament to mimic a coronary artery.

Double bowtie design for high sensitivity pediatric spectral CT.

Despite the evident benefits of spectral computed tomography (CT) in delivering qualitative imaging superior to that of conventional CT in adults, its application in pediatric diagnostic imaging is still relatively limited due to various reasons, including design limitations and radiation dose considerations. The use of specialized K-edge filters, in conjunction with other spectral technologies, has been demonstrated to improve spectral quantification accuracy. X-ray flux limitations generally pose challenges in these concepts when applied to adults.

Lifelike and Deformable Lung Phantoms for 4DCT Imaging: A Three-Dimensional Printing Approach.

Respiratory motion phantoms can be used for evaluation of CT imaging technologies such as motion artifact reduction algorithms and deformable image registration. However, current respiratory motion phantoms do not exhibit detailed lung tissue structures and thus do not provide a realistic testing environment. This paper presents PixelPrint, a method for 3D-printing deformable lung phantoms featuring highly realistic internal structures, suitable for a broad range of CT evaluations, optimizations, and research.

Evaluation of Photon-Counting CT for Spectral Imaging in Cardiovascular Applications: Impact of Lumen Size, Dose, and Patient Habitus.

Objectives: This study evaluates the performance of a clinical dual-source photon-counting computed tomography (PCCT) system in quantifying iodine within calcified vessels, using 3D- printed phantoms with vascular-like structures lined with calcium.

Methods: Parameters assessed include lumen diameters (4, 6, 8, 10, and 12 mm), phantom sizes (S: 20×20 cm, M: 25×25 cm, L: 30×40 cm, XL: 40×50 cm, representing the 99th percentile of US patient sizes), and iodine concentrations (2, 5, and 10 mg/mL). Scans were performed at radiation dose levels of 5, 10, 15, and 20 mGy to systematically evaluate iodine quantification accuracy and spectral imaging performance.

The Effect of the Size of Gold Nanoparticle Contrast Agents on CT Imaging of the Gastrointestinal Tract and Inflammatory Bowel Disease.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD). CT imaging with contrast agents is commonly used for visualizing the gastrointestinal (GI) tract in UC patients. Contrast agents that provide enhanced imaging performance are highly valuable in this field.

Assessing the stability of photon-counting CT: insights from a 2-year longitudinal study.

Objective: Among the advancements in computed tomography (CT) technology, photon-counting computed tomography (PCCT) stands out as a significant innovation, providing superior spectral imaging capabilities while simultaneously reducing radiation exposure. Its long-term stability is important for clinical care, especially longitudinal studies, but is currently unknown. This study sets out to comprehensively analyze the long-term stability of a first-generation clinical PCCT scanner.

: A 3D printing method of fabricating patient-specific deformable CT phantoms for respiratory motion applications.

All in-vivo medical imaging is impacted by patient motion, especially respiratory motion, which has a significant influence on clinical workflows in diagnostic imaging and radiation therapy. Many technologies such as motion artifact reduction and tumor tracking algorithms have been developed to compensate for respiratory motion during imaging. To assess these technologies, respiratory motion phantoms (RMPs) are required as preclinical testing environments, for instance, in computed tomography (CT).

Impact of patient habitus and acquisition protocol on iodine quantification in dual-source photon-counting computed tomography.

Purpose: Evaluation of iodine quantification accuracy with varying iterative reconstruction level, patient habitus, and acquisition mode on a first-generation dual-source photon-counting computed tomography (PCCT) system.

Approach: A multi-energy CT phantom with and without its extension ring equipped with various iodine inserts (0.2 to 15.

Assessing the Stability of Photon-Counting CT: Insights from a Two-Year Longitudinal Study.

Objective: Among the advancements in computed tomography (CT) technology, photon-counting computed tomography (PCCT) stands out as a significant innovation, providing superior spectral imaging capabilities while simultaneously reducing radiation exposure. Its long-term stability is important for clinical care, especially longitudinal studies, but is currently unknown. This study sets out to comprehensively analyze the long-term stability of a first-generation clinical PCCT scanner.

PixelPrint: Generating Patient-Specific Phantoms for Spectral CT using Dual Filament 3D Printing.

In recent years, the importance of spectral CT scanners in clinical settings has significantly increased, necessitating the development of phantoms with spectral capabilities. This study introduces a dual-filament 3D printing technique for the fabrication of multi-material phantoms suitable for spectral CT, focusing particularly on creating realistic phantoms with orthopedic implants to mimic metal artifacts. Previously, we developed PixelPrint for creating patient-specific lung phantoms that accurately replicate lung properties through precise attenuation profiles and textures.

Dual-source photon-counting CT: impact of residual cross-scatter on quantitative spectral results.

Dual-source photon-counting CT combines the high temporal resolution and high pitch of dual-source CT with the material quantification capabilities of photon-counting CT. It, however, results in cross-scatter that increases in severity with increased patient size and collimation. This cross-scatter must be corrected to ensure the removal of scatter artifacts and improve quantitative accuracy.

Lifelike phantoms for assessing clinical image quality and dose reduction capabilities of a deep learning CT reconstruction algorithm.

Deep learning CT reconstruction (DLR) has become increasingly popular as a method for improving image quality and reducing radiation exposure. Due to their nonlinear nature, these algorithms result in resolution and noise performance which are object-dependent. Therefore, traditional CT phantoms, which lack realistic tissue morphology, have become inadequate for assessing clinical imaging performance.

Hybrid spectral CT system with clinical rapid kVp-switching x-ray tube and dual-layer detector for improved iodine quantification.

Spectral computed tomography (CT) is a powerful diagnostic tool offering quantitative material decomposition results that enhance clinical imaging by providing physiologic and functional insights. Iodine, a widely used contrast agent, improves visualization in various clinical contexts. However, accurately detecting low-concentration iodine presents challenges in spectral CT systems, particularly crucial for conditions like pancreatic cancer assessment.

Impact of scatter radiation on spectral quantification performance of first- and second-generation dual-layer spectral computed tomography.

Objective: To assess the impact of scatter radiation on quantitative performance of first and second-generation dual-layer spectral computed tomography (DLCT) systems.

Method: A phantom with two iodine inserts (1 and 2 mg/mL) configured to intentionally introduce high scattering conditions was scanned with a first- and second-generation DLCT. Collimation widths (maximum of 4 cm for first generation and 8 cm for second generation) and radiation dose levels were varied.