Arterio-portal shunts in the cirrhotic liver: perfusion computed tomography for distinction of arterialized pseudolesions from hepatocellular carcinoma.

Objectives: To determine perfusion computed tomography (P-CT) findings for distinction of arterial pseudolesions (APL) from hepatocellular carcinoma (HCC) in the cirrhotic liver.

Methods: 32 APL and 21 HCC in 20 cirrhotic patients (15 men; 65 ± 10 years), who underwent P-CT for evaluation of HCC pre- (N = 9) or post- (N = 11) transarterial chemoembolization, were retrospectively included using CT follow-up as the standard of reference. All 53 lesions were qualitatively (visual) and quantitatively (perfusion parameters) analysed according to their shape (wedge, irregular, nodular), location (not-/adjunct to a fistula), arterial liver perfusion (ALP), portal venous liver perfusion (PLP), hepatic perfusion index (HPI).

Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy.

Aim: To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR).

Materials And Methods: In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current-time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current-time product. Radiation dose parameters from the software were compared with the individual patient protocols.

Long-term follow-up after aortic root replacement with the Shelhigh® biological valved conduit: a word of caution!

Objectives: The aim of this study was to analyse long-term results of aortic root replacement with the Shelhigh® NR-2000C conduit.

Methods: From January 2001 to October 2005, 63 patients with a median age of 62 years underwent aortic root replacement with a Shelhigh® conduit. Aneurysm (27%), aortic valve endocarditis (30%) and acute type A aortic dissection (33%) were the predominant indications for the surgery.

C-arm flat-panel CT arthrography of the shoulder: Radiation dose considerations and preliminary data on diagnostic performance.

Objectives: To investigate radiation dose and diagnostic performance of C-arm flat-panel CT (FPCT) versus standard multi-detector CT (MDCT) shoulder arthrography using MRI-arthrography as reference standard.

Methods: Radiation dose of two different FPCT acquisitions (5 and 20 s) and standard MDCT of the shoulder were assessed using phantoms and thermoluminescence dosimetry. FPCT arthrographies were performed in 34 patients (mean age 44 ± 15 years).

Organ Dose and Attributable Cancer Risk in Lung Cancer Screening with Low-Dose Computed Tomography.

Purpose: Lung cancer screening with CT has been recently recommended for decreasing lung cancer mortality. The radiation dose of CT, however, must be kept as low as reasonably achievable for reducing potential stochastic risks from ionizing radiation. The purpose of this study was to calculate individual patients' lung doses and to estimate cancer risks in low-dose CT (LDCT) in comparison with a standard dose CT (SDCT) protocol.

Quantitative comparison of 2D and 3D late gadolinium enhancement MR imaging in patients with Fabry disease and hypertrophic cardiomyopathy.

Background: This study aims to determine whether the quantification of myocardial fibrosis in patients with Fabry disease (FD) and hypertrophic cardiomyopathy (HCM) using a late gadolinium enhancement (LGE) singlebreath-hold three-dimensional (3D) inversion recovery magnetic resonance (MR) imaging sequence is comparable with a clinically established two-dimensional (2D) multi-breath-hold sequence.

Methods: In this retrospective, IRB-approved study, 40 consecutive patients (18 male; mean age 50±17years) with Fabry disease (n=18) and HCM (n=22) underwent MR imaging at 1.5T.

PATIENT EXPOSURE OPTIMISATION THROUGH TASK-BASED ASSESSMENT OF A NEW MODEL-BASED ITERATIVE RECONSTRUCTION TECHNIQUE.

The goal of the present work was to report and investigate the performances of a new iterative reconstruction algorithm, using a model observer. For that, a dedicated low-contrast phantom containing different targets was scanned at four volume computed tomography dose index (CTDI) levels on a Siemens SOMATOM Force computed tomography (CT). The acquired images were reconstructed using the ADMIRE algorithm and were then assessed by three human observers who performed alternative forced choice experiments.

CT Angiography of the Aorta: Prospective Evaluation of Individualized Low-Volume Contrast Media Protocols.

Purpose To prospectively develop individualized low-volume contrast media (CM) protocols adapted to tube voltage in patients undergoing computed tomographic (CT) angiography of the aorta. Materials and Methods The study was approved by the institutional review board and local ethics committee. All patients provided written informed consent.

Systematic Evaluation of Radiation Dose Reduction in CT Studies of Body Packers: Accuracy Down to Submillisievert Levels.

Objective: The objective of this study was to systematically evaluate the accuracy of abdominal CT performed at different radiation dose levels for the detection of body packs in human cadavers, in comparison with the accuracy of abdominal radiography.

Materials And Methods: In this study, differing numbers of body packs (range, 0-20) were placed in the alimentary tract of human cadavers and then underwent imaging with abdominal radiography and with CT performed at different radiation dose levels (ranging from the standard abdominal CT dose to the technical minimum dose). Depiction of body packs on abdominal radiographs and on each CT scan was assessed by two independent blinded radiologists, and the accuracy of detection of body packs was calculated.

Gouty arthritis: the diagnostic and therapeutic impact of dual-energy CT.

Objectives: To determine the diagnostic and therapeutic impact of dual-energy computed tomography (DECT) in gout.

Methods: Forty-three patients with (n = 20) and without a history of gout (n = 23) showing non-specific soft tissue deposits underwent DECT after unrewarding arthrocentesis. Two blinded, independent readers evaluated DECT for the presence of urate crystals.

Correlation between Dual-Energy and Perfusion CT in Patients with Hepatocellular Carcinoma.

Purpose To develop a dual-energy contrast media-enhanced computed tomographic (CT) protocol by using time-attenuation curves from previously acquired perfusion CT data and to evaluate prospectively the relationship between iodine enhancement metrics at dual-energy CT and perfusion CT parameters in patients with hepatocellular carcinoma (HCC). Materials and Methods Institutional review board and local ethics committee approval and written informed consent were obtained. The retrospective part of this study included the development of a dual-energy CT contrast-enhanced protocol to evaluate peak arterial enhancement of HCC in the liver on the basis of time-attenuation curves from previously acquired perfusion CT data in 20 patients.

Evaluation of pulmonary nodules and infection on chest CT with radiation dose equivalent to chest radiography: Prospective intra-individual comparison study to standard dose CT.

Purpose: To compare prospectively, in patients undergoing chest computed tomography (CT) for pulmonary-nodules or infection, image-quality and accuracy of standard dose (SD) and reduced dose (RD) CT with tin-filtration.

Material And Methods: This IRB-approved study included 100 consecutive patients (36 female;median age 56 years) referred for follow-up of pulmonary-nodules (n=43) or suspicion of infection (n=57) undergoing single-energy CT with SD and RD using tin-filtration at 100 kVp (CTDIvol 2.47 mGy and 0.

Computed Tomography Angiography of Coronary Artery Bypass Grafts: Low Contrast Media Volume Protocols Adapted to Tube Voltage.

Objective: The aim of this study was to evaluate the potential of contrast media (CM) reduction in computed tomography angiography (CTA) of coronary artery bypass grafts (CABGs) when adapting CM volume to automatically selected tube voltages.

Material And Methods: Sixty consecutive patients (mean age, 71 ± 14.5 years) with a total of 176 CABGs (692 bypass segments) underwent contrast-enhanced prospectively electrocardiography-gated high-pitch CTA with automated, attenuation-based tube voltage selection (100 ref.

Ultralow-dose CT with tin filtration for detection of solid and sub solid pulmonary nodules: a phantom study.

Objectives: To investigate the diagnostic performance of advanced modelled iterative reconstruction (ADMIRE) to filtered back projection (FBP) when using an ultralow-dose protocol for the detection of solid and subsolid pulmonary nodules.

Methods: Single-energy CT was performed at 100 kVp with tin filtration in an anthropomorphic chest phantom with solid and subsolid pulmonary nodules (2-10 mm, attenuation, 20 to -800 HU at 120 kVp). The mean volume CT dose index (CTDIvol) of the standard chest protocol was 2.

Influence of Sinogram-Affirmed Iterative Reconstruction on Computed Tomography-Based Lung Volumetry and Quantification of Pulmonary Emphysema.

Objective: The purpose of this study was to evaluate the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on quantification of lung volume and pulmonary emphysema in low-dose chest computed tomography compared with filtered back projection (FBP).

Methods: Enhanced or nonenhanced low-dose chest computed tomography was performed in 20 patients with chronic obstructive pulmonary disease (group A) and in 20 patients without lung disease (group B). Data sets were reconstructed with FBP and SAFIRE strength levels 3 to 5.

Predictive value of low tube voltage and dual-energy CT for successful shock wave lithotripsy: an in vitro study.

This study investigates the capabilities of low tube voltage computed tomography (CT) and dual-energy CT (DECT) for predicting successful shock wave lithotripsy (SWL) of urinary stones in vitro. A total of 33 urinary calculi (six different chemical compositions; mean size 6 ± 3 mm) were scanned using a dual-source CT machine with single- (120 kVp) and dual-energy settings (80/150, 100/150 Sn kVp) resulting in six different datasets. The attenuation (Hounsfield Units) of calculi was measured on single-energy CT images and the dual-energy indices (DEIs) were calculated from DECT acquisitions.

Advanced virtual monoenergetic images: improving the contrast of dual-energy CT pulmonary angiography.

Aim: To investigate the value of advanced virtual monoenergetic image reconstruction (mono-plus) from dual-energy computed tomography (CT) for improving the contrast of CT pulmonary angiography (CTPA).

Materials And Methods: Forty consecutive patients (25 women, mean 62.5 years, range 28-87 years) underwent 192-section dual-source CTPA with dual-energy CT (90/150 SnkVp) after the administration of 60 ml contrast media (300 mg iodine/ml).

Histogram Analysis of CT Perfusion of Hepatocellular Carcinoma for Predicting Response to Transarterial Radioembolization: Value of Tumor Heterogeneity Assessment.

Purpose: To evaluate in patients with hepatocellular carcinoma (HCC), whether assessment of tumor heterogeneity by histogram analysis of computed tomography (CT) perfusion helps predicting response to transarterial radioembolization (TARE).

Materials And Methods: Sixteen patients (15 male; mean age 65 years; age range 47-80 years) with HCC underwent CT liver perfusion for treatment planning prior to TARE with Yttrium-90 microspheres. Arterial perfusion (AP) derived from CT perfusion was measured in the entire tumor volume, and heterogeneity was analyzed voxel-wise by histogram analysis.

MR imaging features for improved diagnosis of hepatocellular carcinoma in the non-cirrhotic liver: Multi-center evaluation.

Purpose: To determine MR-imaging features for the differentiation between hepatocellular carcinoma (HCC) and benign hepatocellular tumors in the non-cirrhotic liver.

Material And Methods: 107 consecutive patients without liver cirrhosis (46 male; 45 ± 14 years) who underwent liver resection due to suspicion of HCC were included in this multi-center study. The following imaging features were assessed: lesion diameter and demarcation, satellite-lesions, central-scar, capsule, fat-content, hemorrhage, vein-infiltration and signal-intensity (SI) on native T1-, T2- and dynamic-enhanced T1-weighted images (center versus periphery).

Metal Artifact Reduction in Pelvic Computed Tomography With Hip Prostheses: Comparison of Virtual Monoenergetic Extrapolations From Dual-Energy Computed Tomography and an Iterative Metal Artifact Reduction Algorithm in a Phantom Study.

Objective: The aim of this study was to directly compare metal artifact reduction (MAR) of virtual monoenergetic extrapolations (VMEs) from dual-energy computed tomography (CT) with iterative MAR (iMAR) from single energy in pelvic CT with hip prostheses.

Materials And Methods: A human pelvis phantom with unilateral or bilateral metal inserts of different material (steel and titanium) was scanned with third-generation dual-source CT using single (120 kVp) and dual-energy (100/150 kVp) at similar radiation dose (CT dose index, 7.15 mGy).

Evolution in Computed Tomography: The Battle for Speed and Dose.

The advent of computed tomography (CT) has revolutionized radiology. Starting as head-only scanners, modern CT systems are now capable of performing whole-body examinations within a couple of seconds in isotropic resolution. Technical advancements of scanner hardware and image reconstruction techniques are reviewed and discussed in their clinical context.

Optimizing radiation dose by using advanced modelled iterative reconstruction in high-pitch coronary CT angiography.

Purpose: To evaluate the potential of advanced modeled iterative reconstruction (ADMIRE) for optimizing radiation dose of high-pitch coronary CT angiography (CCTA).

Methods: High-pitch 192-slice dual-source CCTA was performed in 25 patients (group 1) according to standard settings (ref. 100 kVp, ref.

Advanced virtual monoenergetic computed tomography of hyperattenuating and hypoattenuating liver lesions: ex-vivo and patient experience in various body sizes.

Objective: To determine the value of advanced virtual monoenergetic images (mono+) from dual-energy computed tomography (CT) of hyperattenuating and hypoattenuating liver lesions in various phantom sizes and patients in comparison with standard monoenergetic images (mono).

Materials And Methods: Anthropomorphic phantoms simulating 4 patient sizes (S, 300 × 200 mm; M, 350 × 250 mm; L, 400 × 300 mm; and XL, 600 × 450 mm) with a liver insert containing both hyperattenuating and hypoattenuating iodine-containing lesions were imaged with dose-equivalent dual-energy (100/150 Sn kilovolt [peak] [kV{p}]) and single-energy (120 kV[p]) protocols on a 192-slice dual-source CT system. In addition, 4 patients with 3 hypoattenuating and 3 hyperattenuating hepatocellular carcinoma were included and underwent dual-energy CT imaging with the same scanner at similar kV(p) settings (100/150 Sn kV[p]).

Diagnostic Accuracy of Quantitative and Qualitative Phase-Contrast Imaging for the ex Vivo Characterization of Human Coronary Atherosclerotic Plaques.

Purpose: To investigate the accuracy of x-ray grating interferometry phase-contrast (PC) imaging for the characterization of human coronary artery plaque.

Materials And Methods: PC and conventional absorption computed tomographic (CT) imaging was performed ex vivo in this institutional review board-approved study in 40 human coronary artery segments by using a synchrotron radiation source. Qualitative analyses and calculations of image quality (McNemar test), plaque components (McNemar test), and plaque classification (Cohen κ test) according to the American Heart Association classification were performed in 38 plaques detected at histopathologic examination (reference standard).