Preliminary Results: Can Dual-Energy Computed Tomography Help Distinguish Cardiogenic Pulmonary Edema and Acute Interstitial Lung Disease?

Objective: We compared iodine concentration in pulmonary ground-glass opacity on iodine density images of contrast-enhanced chest dual-energy computed tomography (DECT) between patients with cardiogenic pulmonary edema (CPE) and acute interstitial lung disease (AILD).

Methods: Five of 12 patients who underwent contrast-enhanced chest DECT to exclude pulmonary embolism were clinically diagnosed with CPE and 7, with AILD. We compared the mean CT value on monochromatic images at 65 keV and iodine concentration on iodine density images between the affected and normal areas.

Clinical application of effective atomic number for classifying non-calcified coronary plaques by dual-energy computed tomography.

Background And Aims: Coronary computed tomography (CT) angiography allows non-invasive classification of non-calcified coronary plaques (NCCPs) based on Hounsfield unit (HU) values. This methodology, however, is somewhat limited for reliable classification of NCCPs. Therefore, we evaluated the effective atomic number (EAN) for classifying NCCPs by single-source dual-energy CT with fast tube voltage switching (SSDECT).

Dual-Energy Spectral CT: Various Clinical Vascular Applications.

Single-source dual-energy (DE) computed tomography (CT) with fast switching of tube voltage allows projection-based image reconstruction, substantial reduction of beam-hardening effects, reconstruction of accurate monochromatic images and material decomposition images (MDIs), and detailing of material composition by using x-ray spectral information. In vascular applications, DE CT is expected to overcome limitations of standard single-energy CT angiography, including patient exposure to nephrotoxic contrast medium and carcinogenic radiation, insufficient contrast vascular enhancement, interference from metallic and beam-hardening artifacts and severe vessel calcification, and limited tissue characterization and perfusion assessment. Acquisition of low-energy monochromatic images and iodine/water MDIs can reasonably reduce contrast agent dose and improve vessel enhancement.

Reduction of Coronary Motion Artifacts in Prospectively Electrocardiography-Gated Coronary Computed Tomography Angiography Using Monochromatic Imaging at Various Energy Levels in Combination With a Motion Correction Algorithm on Single-Source Fast Tube Voltage Switching Dual-Energy Computed Tomography: A Phantom Experiment.

Objectives: The aim of this study was to assess the effect of monochromatic imaging at various energy levels in combination with a motion correction algorithm (MCA) in single-source dual-energy coronary computed tomography angiography (CCTA) with fast switching of tube voltage on the reduction of coronary motion artifacts (CMA) in a phantom setting.

Materials And Methods: Using this dual-energy computed tomography technique with a phantom comprising models of coronary vessels filled with contrast medium and pulsating at constant heart rates of 60 to 100 beats per minute, we reconstructed monochromatic images of CCTA obtained at 50 to 90 keV with and without use of MCA. Cardiac motion was modeled by simulating the in vivo time-volume curve of the left ventricle.

Whole-Body Clinical Applications of Digital Tomosynthesis.

With flat-panel detector mammography, radiography, and fluoroscopy systems, digital tomosynthesis (DT) has been recently introduced as an advanced clinical application that removes overlying structures, enhances local tissue separation, and provides depth information about structures of interest by providing high-quality tomographic images. DT images are generated from projection image data, typically using filtered back-projection or iterative reconstruction. These low-dose x-ray projection images are easily and swiftly acquired over a range of angles during a single linear or arc sweep of the x-ray tube assembly.

Current and Novel Imaging Techniques in Coronary CT.

Multidetector coronary computed tomography (CT), which is widely performed to assess coronary artery disease noninvasively and accurately, provides excellent image quality. Use of electrocardiography (ECG)-controlled tube current modulation and low tube voltage can reduce patient exposure to nephrotoxic contrast media and carcinogenic radiation when using standard coronary CT with a retrospective ECG-gated helical scan. Various imaging techniques are expected to overcome the limitations of standard coronary CT, which also include insufficient spatial and temporal resolution, beam-hardening artifacts, limited coronary plaque characterization, and an inability to allow functional assessment of coronary stenosis.

Iterative image reconstruction that includes a total variation regularization for radial MRI.

This paper presents an iterative image reconstruction method for radial encodings in MRI based on a total variation (TV) regularization. The algebraic reconstruction method combined with total variation regularization (ART_TV) is implemented with a regularization parameter specifying the weight of the TV term in the optimization process. We used numerical simulations of a Shepp-Logan phantom, as well as experimental imaging of a phantom that included a rectangular-wave chart, to evaluate the performance of ART_TV, and to compare it with that of the Fourier transform (FT) method.

Influence of the motion correction algorithm on the quality and interpretability of images of single-source 64-detector coronary CT angiography among patients grouped by heart rate.

Purpose: We retrospectively investigated the effect of the motion correction algorithm (MCA) on image quality and interpretability by heart rate (HR) in coronary CT angiography (CCTA).

Materials And Methods: For 105 patients (6 HR groups) undergoing CCTA, 2 readers independently graded the image quality of the 4 major coronary arteries reconstructed with and without MCA at diastole with HR ≤64 bpm and at systole and diastole ≥65 bpm using a 5-point scale. For each HR group and cardiac phase, we compared per-vessel and per-segment image quality using Wilcoxon signed rank test and percentages of interpretable image quality (scores 3-5) among without MCA at diastole with HR ≤64 bpm, as a reference, with MCA at diastole ≤69 bpm and at systole 70-79 bpm using the chi-square test.

Analysis of coronary arterial calcification components with coronary CT angiography using single-source dual-energy CT with fast tube voltage switching.

Clinical cardiac applications of single-source dual-energy computed tomography (DECT) have recently been introduced. This study aimed to analyze the components of coronary arterial calcification (CAC) in vivo by material decomposition achieved with DECT. We reconstructed computed tomography (CT) angiography images for 51 consecutive patients with CACs who had undergone electrocardiography-gated coronary CT angiography by single-source DECT with fast tube voltage switching.

CT of the pancreas: comparison of image quality and pancreatic duct depiction among model-based iterative, adaptive statistical iterative, and filtered back projection reconstruction techniques.

The purpose of this study is to compare CT images of the pancreas reconstructed with model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASiR), and filtered back projection (FBP) techniques for image quality and pancreatic duct (PD) depiction. Data from 40 patients with contrast-enhanced abdominal CT [CTDIvol: 10.3 ± 3.

A method for selecting a protocol for routine body CT scan using Gemstone Spectral Imaging with or without adaptive statistical iterative reconstruction: phantom experiments.

Purpose: To investigate a method for selecting a protocol for body CT scan to acquire monochromatic images (MIs) by gemstone spectral imaging (GSI) with or without adaptive statistical iterative reconstruction (ASiR).

Materials And Methods: We subjected a phantom to conventional scanning at 120 kVp and 50-700 mAs and GSI at 165-600 mAs; reconstructed MIs at 65 keV with ASiR 0-100 % for GSI; placed 5 regions of interest on each of 3 consecutive reconstructed slices to obtain the averaged standard deviation (SD) as image noise for conventional scan and GSI. Linear regression analysis yielded the mAs by conventional scan that could be used to achieve similar image noise by GSI.

Diameter measurement of vascular model on CT angiography using model-based iterative reconstruction: effect of tube current on accuracy.

Objective: The purpose of this study was to evaluate the effect of tube current on the accuracy of vascular diameter measurements on CT angiography using model-based iterative reconstruction (MBIR).

Materials And Methods: We constructed a physical phantom composed of nine vascular models of three wall thicknesses filled with contrast material of three densities and scanned the phantom using a 64-MDCT unit with tube currents of 80, 40, 20, and 10 mA. We reconstructed raw data using MBIR and filtered back projection (FBP) algorithms and examined image sharpness by edge rise distance using four tube currents in each of the two reconstruction methods.

Dual-energy subtraction radiography improves laryngeal delineation in patients with moderate to severe cervical spondylosis.

Purpose: To investigate the feasibility of dual-energy subtraction (DES) in patients with moderate-severe cervical spondylosis for improving delineation of the larynx on flat panel detector (FPD) radiography.

Materials And Methods: For 118 patients, we graded conventional/DES anterior-posterior views for delineation of the vocal cords, subglottis, and pyriform sinus using a 5-point scale and lateral views from conventional laryngeal FPD radiography to determine cervical spondylosis severity on a scale from 0 (none) to 3 (severe). We compared the delineation of each anatomical structure in both groups of grades 0-1 and grades 2-3 of spondylosis severity between conventional and DES methods and the improved delineation rate for each anatomical structure by DES compared to the conventional method between both groups.

Reproducibility of scan prescription in follow-up brain MRI: manual versus automatic determination.

In follow-up brain magnetic resonance imaging (MRI), precise reproducibility of the scan prescription is important so that over- or underestimating changes in volumes of clinical interest is prevented. (The scan prescription is defined as the location and orientation of the head with respect to the scan planes of the three-dimensional MRI matrix.) In this study, the misregistration between the original and a second scan was calculated in the case of both manual positioning and automatic positioning.

Detection of paranasal sinus opacification with digital tomosynthesis radiography: a clinical pilot study.

Objective: We investigated the diagnostic accuracy of digital tomosynthesis (DT) radiography for detecting sinus opacification.

Methods: For 31 adult patients with signs suggestive of sinusitis who underwent both sinus multi-detector-row computed tomography and DT, 2 readers independently assessed opacification in the maxillary, ethmoid, frontal, and sphenoid sinuses by DT and in consensus determined the presence of opacification in each sinus by multi-detector-row computed tomography as a reference. We assessed the diagnostic accuracy of DT and interreader agreement with DT using Cohen κ statistics.

Vascular diameter measurement in CT angiography: comparison of model-based iterative reconstruction and standard filtered back projection algorithms in vitro.

Objective: The purpose of this study was to evaluate the performance of model-based iterative reconstruction (MBIR) in measurement of the inner diameter of models of blood vessels and compare performance between MBIR and a standard filtered back projection (FBP) algorithm.

Materials And Methods: Vascular models with wall thicknesses of 0.5, 1.

Origin of sylvian hematoma in patients with subarachnoid hemorrhage: findings of extravasation on multiphase contrast-enhanced computed tomography.

Objective: Sylvian hematoma in subarachnoid hemorrhage (SAH) is associated with a poor prognosis. Although active bleeding can be detected by multiphase dynamic enhanced computed tomography (CT), bleeding from vessels in the Sylvian fissure has also been found in Sylvian hematoma. We investigated possible origins of Sylvian hematoma based on novel imaging findings of multiphase enhanced CT.

Improved delineation of the anterior spinal artery with model-based iterative reconstruction in CT angiography: a clinical pilot study.

Objective: The purpose of this study was to investigate the utility of model-based iterative reconstruction (MBIR) for improving delineation of the anterior spinal artery (ASA) during routine-dose CT angiography.

Materials And Methods: For imaging of 10 patients (six men, four women; mean age, 73.9 ± 7.

Depicting the semicircular canals with inner-ear MRI: a comparison of the SPACE and TrueFISP sequences.

Purpose: To assess the ability of magnetic resonance imaging (MRI) to depict the semicircular canals of the inner ear by comparing results from the sampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE) sequence with those from the true free induction with steady precession (TrueFISP) sequence.

Materials And Methods: A 1.5-T MRI system was used to perform an in vivo study of 10 healthy volunteers and 17 patients.

Usefulness of left ventricular diastolic function assessed by magnetic resonance imaging over invasive coronary flow reserve measurement for detecting cardiac allograft vasculopathy in heart transplant recipients.

Heart transplant recipients undergo annual screening of early-stage cardiac allograft vasculopathy (CAV) by invasive coronary flow reserve (CFR) measurement. We compared the sensitivity for CAV detection between the CFR measurement and noninvasive magnetic resonance (MR) assessment of left ventricular (LV) diastolic function. In 46 asymptomatic recipients (29 men, aged 35.

Measurement of vascular wall attenuation: comparison of CT angiography using model-based iterative reconstruction with standard filtered back-projection algorithm CT in vitro.

Objectives: To compare the performance of model-based iterative reconstruction (MBIR) with that of standard filtered back projection (FBP) for measuring vascular wall attenuation.

Study Design: After subjecting 9 vascular models (actual attenuation value of wall, 89 HU) with wall thickness of 0.5, 1.

Pull-through technique with pincer tactics for stent placement in severe superior vena cava syndrome.

The pull-through technique is an interventional radiological procedure used when an occluded lesion cannot be traversed from one direction. To pass the lesion, a long guidewire is traversed from the opposite side and pulled through the ipsilateral sheath using a snare wire. The present report describes a case of severe superior vena cava syndrome treated by stent placement using a pull-through technique with pincer tactics.

Percutaneous transhepatic drainage of lung abscess through a diaphragmatic fistula caused by a penetrating liver abscess.

Liver abscesses occurring just below the diaphragm can penetrate or perforate the thoracic cavity, resulting in lung abscess or pyothorax. Although surgical or percutaneous transpleural drainage is often required in such cases, the latter approach has some risks, including hemothorax and bronchopleural fistula formation when the cavity is surrounded by normal lung parenchyma. The present report describes a treatment technique of percutaneous transhepatic drainage through the diaphragmatic fistula to avoid the risks of a transpulmonary approach in a case of lung abscess caused by a penetrating liver abscess.

Perfusion fraction of diffusion-weighted MRI for predicting the presence of blood supply in ovarian masses.

Purpose: To evaluate whether perfusion fraction (PF) calculated with diffusion-weighted magnetic resonance imaging (MRI) predicts the presence of blood supply in ovarian masses.

Materials And Methods: PFs of 92 ovarian lesions in 53 patients administered gadolinium were retrospectively calculated with diffusion-weighted images at b-values of 0, 500, and 1000 sec/mm(2). PFs were compared between ovarian lesions, except for fat, with (n = 21) or without contrast enhancement (n = 57), using Student's t-test and receiver operating characteristics (ROC) curve analysis.

Postoperative follow-up of olecranon fracture by digital tomosynthesis radiography.

Digital tomosynthesis with flat-panel detector radiography is a novel application that allows easy, swift volume data acquisition of any anatomical site of interest with arbitrary patient posture. A single sweep of the X-ray tube provides multiple tomographic images of high resolution. We present the first patient with olecranon fracture who underwent internal fixation and 1-year postoperative follow-up with tomosynthesis.