Correlation of Radiomics with Treatment Response in Liver Metastases.

Rationale And Objectives: To assess differences in radiomics derived from semi-automatic segmentation of liver metastases for stable disease (SD), partial response (PR), and progressive disease (PD) based on RECIST1.1 and to assess if radiomics alone at baseline can predict response.

Materials And Methods: Our IRB-approved study included 203 women (mean age 54 ± 11 years) with metastatic liver disease from breast cancer.

Visceral adipose tissue volume effect in Crohn's disease using reduced exposure CT enterography.

Purpose: The purpose of this investigation was to assess the effect of visceral adipose tissue volume (VA) on reader efficacy in diagnosing and characterizing small bowel Crohn's disease using lower exposure CT enterography (CTE). Secondarily, we investigated the effect of lower exposure and VA on reader diagnostic confidence.

Methods: Prospective paired investigation of 256 CTE, 129 with Crohn's disease, were reconstructed at 100% and simulated 50% and 30% exposure.

Effect of tin spectral filtration on organ and effective dose in CT colonography and CT lung cancer screening.

Background: Studies of tin spectral filtration have demonstrated potential in reducing radiation dose while maintaining image quality for unenhanced computed tomography (CT) scans. The extent of dose reduction, however, was commonly measured using the change in the scanner's reported CTDI . This method does not account for how tin filtration affects patient organ and effective dose.

Performance of threshold-based stone segmentation and radiomics for determining the composition of kidney stones from single-energy CT.

Purpose: Knowledge of kidney stone composition can help in patient management; urine composition analysis and dual-energy CT are frequently used to assess stone type. We assessed if threshold-based stone segmentation and radiomics can determine the composition of kidney stones from single-energy, non-contrast abdomen-pelvis CT.

Methods: With IRB approval, we identified 218 consecutive patients (mean age 64 ± 13 years; male:female 138:80) with the presence of kidney stones on non-contrast, abdomen-pelvis CT and surgical or biochemical proof of their stone composition.

Using barium as an internal radioprotective shield for pregnant patients undergoing CT pulmonary angiography: A retrospective study.

Purpose: The purpose of our retrospective study was to assess the effect of barium sulfate contrast medium on radiation dose and diagnostic quality of CT Pulmonary Angiography (CTPA) in an in-vivo study of pregnant patients.

Methods: Our retrospective study included 33 pregnant patients who underwent CTPA to exclude pulmonary embolism. The patients received oral 40% w/v barium solution just prior to the acquisition of their planning radiograph.

Spectral segmentation and radiomic features predict carotid stenosis and ipsilateral ischemic burden from DECT angiography.

PURPOSE The purpose of this study is to compare spectral segmentation, spectral radiomic, and single- energy radiomic features in the assessment of internal and common carotid artery (ICA/CCA) stenosis and prediction of surgical outcome. METHODS Our ethical committee-approved, Health Insurance Portability and Accountability Act (HIPAA)- compliant study included 85 patients (mean age, 73 ± 10 years; male : female, 56 : 29) who under- went contrast-enhanced, dual-source dual-energy CT angiography (DECTA) (Siemens Definition Flash) of the neck for assessing ICA/CCA stenosis. Patients with a prior surgical or interventional treatment of carotid stenosis were excluded.

Complex Relationship Between Artificial Intelligence and CT Radiation Dose.

Concerns over need for CT radiation dose optimization and reduction led to improved scanner efficiency and introduction of several reconstruction techniques and image processing-based software. The latest technologies use artificial intelligence (AI) for CT dose optimization and image quality improvement. While CT dose optimization has and can benefit from AI, variations in scanner technologies, reconstruction methods, and scan protocols can lead to substantial variations in radiation doses and image quality across and within different scanners.

Artificial Intelligence has Similar Performance to Subjective Assessment of Emphysema Severity on Chest CT.

Rationale And Objectives: To compare an artificial intelligence (AI)-based prototype and subjective grading for predicting disease severity in patients with emphysema.

Methods: Our IRB approved HIPAA-compliant study included 113 adults (71±8 years; 47 females, 66 males) who had both non-contrast chest CT and pulmonary function tests performed within a span of 2 months. The disease severity was classified based on the forced expiratory volume in 1 second (FEV1 as % of predicted) into mild, moderate, and severe.

Characterization of Benign and Malignant Pancreatic Lesions with DECT Quantitative Metrics and Radiomics.

Rationale And Objectives: To compare dual energy CT (DECT) quantitative metrics and radiomics for differentiating benign and malignant pancreatic lesions on contrast enhanced abdomen CT.

Materials And Methods: Our study included 103 patients who underwent contrast-enhanced DECT for assessing focal pancreatic lesions at one of the two hospitals (Site A: age 68 ± 12 yrs; malignant = 41, benign = 18; Site B: age 46 ± 2 yrs; malignant = 23, benign = 21). All malignant lesions had histologic confirmation, and benign lesions were stable on follow up CT (>12 months) or had characteristic benign features on MRI.

Use of radiomics to differentiate left atrial appendage thrombi and mixing artifacts on single-phase CT angiography.

To assess if radiomics can differentiate left atrial appendage (LAA) contrast-mixing artifacts and thrombi on early-phase CT angiography without the need for late-phase images. Our study included 111 patients who underwent early- and late-phase, contrast-enhanced cardiac CT. Of these, 79 patients had LAA filling defects from thrombus (n = 46, mean age: 72  ±  12 years, M:F 26:20) or contrast-mixing artifact (n = 33, mean age: 71  ±  13 years, M:F 21:12) on early-contrast-enhanced phase.

Effect of obesity on ability to lower exposure for detection of low-attenuation liver lesions.

Purpose: The purpose of this study was to assess the effect of obesity and iterative reconstruction on the ability to reduce exposure by studying the accuracy for detection of low-contrast low-attenuation (LCLA) liver lesions on computed tomography (CT) using a phantom model.

Methods: A phantom with four unique LCLA liver lesions (5- to 15-mm spheres, -24 to -6 HU relative to 90-HU background) was scanned without ("thin" phantom) and with ("obese" phantom) a 5-cm thick fat-attenuation ring at 150 mAs (thin phantom) and 450 mAs (obese phantom) standard exposures and at 33% and 67% exposure reductions. Images were reconstructed using standard filtered back projection (FBP) and with iterative reconstruction (Adaptive Model-Based Iterative Reconstruction strength 3, ADMIRE).

Prediction of burden and management of renal calculi from whole kidney radiomics: a multicenter study.

Purpose: To assess if autosegmentation-assisted radiomics can predict disease burden, hydronephrosis, and treatment strategies in patients with renal calculi.

Methods: The local ethical committee-approved, retrospective study included 202 adult patients (mean age: 53 ± 17 years; male: 103; female: 99) who underwent clinically indicated, non-contrast abdomen-pelvis CT for suspected or known renal calculi. All CT examinations were reviewed to determine the presence (n = 123 patients) or absence (n = 79) of renal calculi.

Low-dose CT with metal artifact reduction in arthroplasty imaging: a cadaveric and clinical study.

Objective: To determine whether a simulated low-dose metal artifact reduction (MAR) CT technique is comparable with a clinical dose MAR technique for shoulder arthroplasty evaluation.

Materials And Methods: Two shoulder arthroplasties in cadavers and 25 shoulder arthroplasties in patients were scanned using a clinical dose (140 kVp, 300 qrmAs); cadavers were also scanned at half dose (140 kVp, 150 qrmAs). Images were reconstructed using a MAR CT algorithm at full dose and a noise-insertion algorithm simulating 50% dose reduction.

Dual-energy CT arthrography: a feasibility study.

Objective: To evaluate the feasibility of producing 2-dimensional (2D) virtual noncontrast images and 3-dimensional (3D) bone models from dual-energy computed tomography (DECT) arthrograms and to determine whether this is best accomplished using 190 keV virtual monoenergetic images (VMI) or virtual unenhanced (VUE) images.

Materials And Methods: VMI and VUE images were retrospectively reconstructed from patients with internal derangement of the shoulder or knee joint who underwent DECT arthrography between September 2017 and August 2019. A region of interest was placed in the area of brightest contrast, and the mean attenuation (in Hounsfield units [HUs]) was recorded.

Dual energy CT in clinical routine: how it works and how it adds value.

Dual energy computed tomography (DECT), also known as spectral CT, refers to advanced CT technology that separately acquires high and low energy X-ray data to enable material characterization applications for substances that exhibit different energy-dependent x-ray absorption behavior. DECT supports a variety of post-processing applications that add value in routine clinical CT imaging, including material selective and virtual non-contrast images using two- and three-material decomposition algorithms, virtual monoenergetic imaging, and other material characterization techniques. Following a review of acquisition and post-processing techniques, we present a case-based approach to highlight the added value of DECT in common clinical scenarios.

Combined Dual-Energy and Single-Energy Metal Artifact Reduction Techniques Versus Single-Energy Techniques Alone for Lesion Detection Near an Arthroplasty.

The purpose of this study was to compare a combined dual-energy CT (DECT) and single-energy CT (SECT) metal artifact reduction technique with a SECT metal artifact reduction technique for detecting lesions near an arthroplasty in a phantom model. Two CT phantoms with a cobalt chromium sphere attached to a titanium rod, simulating an arthroplasty, within a background of soft-tissue attenuation containing spherical lesions (range, 10-20 mm) around the head and stem of different attenuations from the background (range of attenuation, 10-70 HU) were scanned with a single CT scanner individually (unilateral) and together (bilateral) with the following three dose-equivalent techniques: the currently used clinical protocol (140 kVp, 300 Reference mAs); 100 kVp; and DECT (100 kVp and 150 kVp with a tin filter). Three radiologists reviewed the datasets to identify lesions.

Reducing Radiation Dose and Contrast Medium Volume With Application of Dual-Energy CT in Children and Young Adults.

The purpose of this study was to assess if dual-source dual-energy CT (DS-DECT) can be used with lower radiation doses and contrast material volumes than single-energy CT (SECT) in children and young adults. This retrospective study included 85 consecutive children and young adults (age range, 1 month old to 19 years old; 81 male, 70 female) who underwent contrast-enhanced DS-DECT of the chest ( = 41) or the abdomen and pelvis ( = 44) on second- or third-generation dual-source CT scanners (Somatom Flash or Force, Siemens Healthineers) for clinically indicated reasons. We included 66 age-, sex-, body region-, and weight-matched patients who underwent SECT on the same scanner.

Can Dual-Energy Computed Tomography Quantitative Analysis and Radiomics Differentiate Normal Liver From Hepatic Steatosis and Cirrhosis?

Objectives: This study aimed to assess if dual-energy computed tomography (DECT) quantitative analysis and radiomics can differentiate normal liver, hepatic steatosis, and cirrhosis.

Materials And Methods: Our retrospective study included 75 adult patients (mean age, 54 ± 16 years) who underwent contrast-enhanced, dual-source DECT of the abdomen. We used Dual-Energy Tumor Analysis prototype for semiautomatic liver segmentation and DECT and radiomic features.

Comparative assessment of qualitative and quantitative perfusion with dual-energy CT and planar and SPECT-CT V/Q scanning in patients with chronic thromboembolic pulmonary hypertension.

Background: The purpose of this study was to compare the qualitative and quantitative assessment of perfusion on dual-energy CT (DECT) and planar and single photon emission computed tomography (SPECT)-CT V/Q scanning in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

Methods: Nineteen patients with known CTEPH underwent both DECT and SPECT-CT V/Q scanning. Sixteen of these patients underwent planar V/Q imaging concurrently.

Motion Artifact Reduction From High-Pitch Dual-Source Computed Tomography Pulmonary Angiography.

Purpose: The purpose of this study was to compare quantitative and qualitative measures of aortic, cardiac, and respiratory motion artifact between high-pitch dual-source (DS) and single-source (SS) computed tomography pulmonary angiography (CTPA) protocols.

Methods: This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study retrospectively reviewed 80 non-electrocardiogram-gated CTPA examinations acquired with a second-generation DS system at 100 kVp following 50 mL iodinated contrast injection - 40 consecutive SS and 40 consecutive DS studies. Quantitative measures of aortic, left ventricular, and diaphragmatic motion were recorded as the maximal excursion of a structure's "double image," and 3 independent readers performed qualitative motion assessments.

Dose Reduction With Dedicated CT Metal Artifact Reduction Algorithm: CT Phantom Study.

Objective: The objective of this study was to compare reader accuracy detecting lesions near hardware in a CT phantom model at different radiation exposures using an advanced metal artifact reduction (MAR) algorithm and standard filtered back projection (FBP) techniques and to determine if radiation exposure could be decreased using MAR without compromising lesion detectability.

Materials And Methods: A CT phantom manufactured with spherical lesions of various sizes (10-20 mm) and attenuations (20-50 HU) embedded around cobalt-chromium spheres attached to titanium rods, simulating an arthroplasty, was scanned on a single CT scanner (FLASH, Siemens Healthcare) at 140 kVp and 0.6-mm collimation using clinical-dose (300 Quality Reference mAs [Siemens Healthcare]), low-dose (150 Quality Reference mAs), and high-dose (600 Quality Reference mAs) protocols.

Extending the concept of weighted CT dose index to elliptical phantoms of various aspect ratios.

The purpose of this study was to extend the concept of weighted CT dose index ([Formula: see text]) to the elliptical phantoms. Based on the published body dimension data, eight body aspect ratios were chosen between 1 (perfectly circular) and 1.72 (extremely elliptical).

Analysis of uncertainties in Monte Carlo simulated organ and effective dose in chest CT: scanner- and scan-related factors.

In Monte Carlo simulation of CT dose, many input parameters are required (e.g. bowtie filter properties and scan start/end location).

Attenuation-based kV pair selection in dual source dual energy computed tomography angiography of the chest: impact on radiation dose and image quality.

Objectives: The purpose of this study was to evaluate the impact of attenuation-based kilovoltage (kV) pair selection in dual source dual energy (DSDE)-pulmonary embolism (PE) protocol examinations on radiation dose savings and image quality.

Methods: A prospective study was carried out on 118 patients with suspected PE. In patients in whom attenuation-based kV pair selection selected the 80/140Sn kV pair, the pre-scan 100/140Sn CTDIvol (computed tomography dose index volume) values were compared with the pre-scan 80/140Sn CTDIvol values.

Point Organ Radiation Dose in Abdominal CT: Effect of Patient Off-Centering in an Experimental Human Cadaver Study.

To determine the effect of patient off-centering on point organ radiation dose measurements in a human cadaver scanned with routine abdominal CT protocol. A human cadaver (88 years, body-mass-index 20 kg/m2) was scanned with routine abdominal CT protocol on 128-slice dual source MDCT (Definition Flash, Siemens). A total of 18 scans were performed using two scan protocols (a) 120 kV-200 mAs fixed-mA (CTDIvol 14 mGy) (b) 120 kV-125 ref mAs (7 mGy) with automatic exposure control (AEC, CareDose 4D) at three different positions (a) gantry isocenter, (b) upward off-centering and (c) downward off-centering.