Image Update Research Articles

Common and Uncommon Benign Pancreatic Lesions Mimicking Malignancy: Imaging Update and Review

There is a broad range of inflammatory, pseudotumoral, and benign lesions that may masquerade as pancreatic malignancies, often representing a challenge to the radiologist. Unawareness of these entities can lead to inadequate differential diagnoses or misdiagnosis, with important prognostic and therapeutic consequences. The purpose of this article is to revisit a spectrum of lesions, varying from common to exceedingly rare nonmalignant, that may mimic malignant pancreatic neoplasms on imaging, identifying relevant features that may contribute to reaching the correct diagnosis. Representative cases include focal fatty replacement, intrapancreatic accessory spleen, pancreatic lobulation, lipoma, autoimmune pancreatitis, focal pancreatitis, eosinophilic pancreatitis, groove pancreatitis, hemangioma, intrapancreatic aneurysm, tuberculosis, and Castleman's disease.

Breast Imaging Update: Guidelines, Recall Rates and Personalized Care

Breast Imaging Update: Guidelines, Recall Rates and Personalized Care

Pediatric Thyroid Cancer: Imaging and Therapy Update

In 2015, the management of thyroid cancer in the pediatric population was overhauled with the publication of the inaugural American Thyroid Association guidelines for children with thyroid nodules and differentiated thyroid cancer. In this article, we review these guidelines along with recent relevant literature regarding pediatric thyroid cancer, focusing on salient issues relating to imaging and radionuclide therapy. The American College of Radiology recently published its inaugural recommendations for thyroid nodule imaging (TI-RADS). Regarding radionuclide therapy, recent literature has focused on ways to reduce long-term sequelae while providing optimal initial treatment. While a more standardized approach is being taken towards initial imaging of thyroid nodules and cancer, the opposite approach to treatment and surveillance is developing, with a focus on personalization.

A fast beam hardening correction method incorporated in a filtered back-projection based MAP algorithm

The beam hardening effect can induce strong artifacts in CT images, which result in severely deteriorated image quality with incorrect intensities (CT numbers). This paper develops an effective and efficient beam hardening correction algorithm incorporated in a filtered back-projection based maximum a posteriori (BHC-FMAP). In the proposed algorithm, the beam hardening effect is modeled and incorporated into the forward-projection of the MAP to suppress beam hardening induced artifacts, and the image update process is performed by Feldkamp–Davis–Kress method based back-projection to speed up the convergence. The proposed BHC-FMAP approach does not require information about the beam spectrum or the material properties, or any additional segmentation operation. The proposed method was qualitatively and quantitatively evaluated using both phantom and animal projection data. The experimental results demonstrate that the BHC-FMAP method can efficiently provide a good correction of beam hardening induced artefacts.

Solid-state 3D imaging using a 1nJ/100ps laser diode transmitter and a single photon receiver matrix.

A 3D imaging concept based on pulsed time-of-flight focal plane imaging is presented which can be tailored flexibly in terms of performance parameters such as range, image update rate, field-of-view, 2D resolution, depth accuracy, etc. according to the needs of different applications. The transmitter is based on a laser diode operating in enhanced gain-switching mode with a simple MOS/CMOS-switch current driver and capable of producing short (~100ps FWHM) high energy (up to nJ) pulses at a high pulsing rate. The receiver consists of 2D SPAD and TDC arrays placed on the same die, but in separate arrays. Paraxial optics can be used to illuminate the target field-of-view with the receiver placed at the focal plane of the receiver lens. To validate the concept, a prototype system is presented with a bulk laser diode/MOS driver operating at a wavelength of 870nm with a pulsing rate of 100kHz as the transmitter and a single-chip 9x9 SPAD array with 10-channel TDC as the receiver. The possibility of using this method as a solid-state solution to the task of 3D imaging is discussed in the light of the results derived from this prototype.

Updates in breast imaging: TMIST, guidelines and tomosynthesis technology

Updates in breast imaging: TMIST, guidelines and tomosynthesis technology

Human short-latency ocular vergence responses produced by interocular velocity differences.

We studied human short-latency vergence eye movements to a novel stimulus that produces interocular velocity differences without a changing disparity signal. Sinusoidal luminance gratings moved in opposite directions (left vs. right; up vs. down) in the two eyes. The grating seen by each eye underwent ¼-wavelength shifts with each image update. This arrangement eliminated changing disparity cues, since the phase difference between the eyes alternated between 0° and 180°. We nevertheless observed robust short-latency vergence responses (VRs), whose sign was consistent with the interocular velocity differences (IOVDs), indicating that the IOVD cue in isolation can evoke short-latency VRs. The IOVD cue was effective only when the images seen by the two eyes overlapped in space. We observed equally robust VRs for opposite horizontal motions (left in one eye, right in the other) and opposite vertical motions (up in one eye, down in the other). Whereas the former are naturally generated by objects moving in depth, the latter are not part of our normal experience. To our knowledge, this is the first demonstration of a behavioral consequence of vertical IOVD. This may reflect the fact that some neurons in area MT are sensitive to these motion signals (Czuba, Huk, Cormack, & Kohn, 2014). VRs were the strongest for spatial frequencies in the range of 0.35–1 c/°, much higher than the optimal spatial frequencies for evoking ocular-following responses observed during frontoparallel motion. This suggests that the two motion signals are detected by different neuronal populations. We also produced IOVD using moving uncorrelated one-dimensional white-noise stimuli. In this case the most effective stimuli have low speed, as predicted if the drive originates in neurons tuned to high spatial frequencies (Sheliga, Quaia, FitzGibbon, & Cumming, 2016).

MR Imaging Applications in Mild Traumatic Brain Injury: An Imaging Update.

Mild traumatic brain injury (mTBI), also commonly referred to as concussion, affects millions of Americans annually. Although computed tomography is the first-line imaging technique for all traumatic brain injury, it is incapable of providing long-term prognostic information in mTBI. In the past decade, the amount of research related to magnetic resonance (MR) imaging of mTBI has grown exponentially, partly due to development of novel analytical methods, which are applied to a variety of MR techniques. Here, evidence of subtle brain changes in mTBI as revealed by these techniques, which are not demonstrable by conventional imaging, will be reviewed. These changes can be considered in three main categories of brain structure, function, and metabolism. Macrostructural and microstructural changes have been revealed with three-dimensional MR imaging, susceptibility-weighted imaging, diffusion-weighted imaging, and higher order diffusion imaging. Functional abnormalities have been described with both task-mediated and resting-state blood oxygen level-dependent functional MR imaging. Metabolic changes suggesting neuronal injury have been demonstrated with MR spectroscopy. These findings improve understanding of the true impact of mTBI and its pathogenesis. Further investigation may eventually lead to improved diagnosis, prognosis, and management of this common and costly condition. (©) RSNA, 2016.

Developmental venous anomalies of the brain in children -- imaging spectrum and update.

Developmental venous anomalies (DVAs) are the most common vascular malformation of the brain and are commonly identified on routine imaging of the brain. They are typically considered incidental findings, usually with no clinical significance. However the increasing identification of DVAs as a result of improved imaging technology has led to recognition of their association with a variety of abnormal imaging findings and clinically important conditions. This pictorial essay explores the suspected embryological origin, associated imaging features, and proposed pathophysiological mechanisms of DVAs in the pediatric population. This paper emphasizes newer physiological imaging data, which suggest that DVA drainage has less physiological flexibility than otherwise normal venous drainage development.

“Weak Links” of the Pediatric Skeleton: Common Foci for Disease and Trauma. Part 2—Areas of Weakness Beyond Bone and Cartilage Transitions

In this article, we review recent updates in the radiologic imaging of injuries to the pediatric skeleton. While part 1 focused on areas of weakness at cartilage–bone interfaces, part 2 focuses on other areas of the developing skeleton that are uniquely susceptible to injury. Over the past 5 years new and interesting research has helped us better understand the disease processes and how to image these “weak links.” These cartilage–bone interfaces are unique to the pediatric skeleton, and an understanding of this anatomy is critical in the performance and interpretation of pediatric musculoskeletal imaging examinations.

“Weak Links” of the Pediatric Skeleton: Common Foci for Disease and Trauma. Part 1: The Link Between Bone and Cartilage

In this article, we review recent updates in the radiologic imaging of injuries to the pediatric skeleton. In part 1, we focus on the link between cartilage and bone. Part 2 focuses on other areas of the developing skeleton that are susceptible to injury. Over the past 5 years, new and interesting research has helped us to better understand pediatric skeletal disease processes and how to image these “weak links.” These cartilage–bone interfaces are unique to the pediatric skeleton, and understanding of this anatomy is critical in the performance and interpretation of pediatric musculoskeletal imaging examinations.

Dynamic properties of a small-size streak tube

Scannerless (flash) lidar system based on streak camera is able to realize three-dimensional (3D) multi-spectral fluorescence imaging and 3D imaging polarimetry. Compared with conventional lidar system, the flash lidar system overcomes image distortions caused by the motion between the target and the sensor platform. Other advantages of the flash lidar system are higher image update rates and the potential for creating a miniaturized lidar system. To meet the requirements for developing this new technology, a super small-sized, large photocathode area and meshless streak tube with spherical cathode and screen is designed with the aid of computer simulation technology (CST) software. The tube with nearly 28 mm wide photocathode work area contains two electrostatic focusing lens, a pair of deflection plates, and a 50 mm diameter output screen. The external dimension of the tube is merely 50 mm100 mm. And its electromagnetic fields are calculated in the CST Particle Studio based on the finite integration theory. Some dynamic properties of the tube are analyzed via observing different electron trajectories launched from a number of different points on the cathode. The influences of the deflector position on deflection sensitivity and spatial resolution are analyzed. Increasing the distance between the deflector and the anode pin hole leads to a worse deflection sensitivity but a better spatial resolution. As for the temporal resolution, three electron pulses separated by 30 ps can be well resolved by the streak tube in the dynamic mode. Thus, the dynamic temporal resolution of the streak tube is better than 30 ps. And a 10 lp/mm spatial resolution across the 28 mm long slit on the photocathode can be obtained by estimating modulation transfer functions of the electron trajectories. Temporal distortions at the entire photocathode working area are evaluated, and the data reveal that the larger the photocathode working area, the bigger the temporal distortions are. Also, the temporal distortion is present mainly in the photocathode-to-deflection plates region. In addition, the slit image of the streak tube working in the dynamic mode is simulated and presented. The phenomenon that the slit image is curved due to the temporal distortion is analyzed. Two rectangular electron pulses separated by 50 ps are well resolved by the streak tube. Therefore, the temporal resolution of this small-size steak tube is better than 50 ps with a rectangular slit dimension of 30 mm50 m on the photocathode, and its electron-optic magnification is 1.2.

Current Gastrointestinal Imaging in Children.

Gastrointestinal (GI) pathologies in children present with overlapping symptoms and signs. Radiological imaging is assuming a more prominent role in the diagnostic pathway. This article is aimed primarily at paediatricians, helping them to understand and thereby better utilise radiological imaging. The strengths and weaknesses of the various imaging modalities are outlined in a concise manner. Illustrative conditions are discussed with an emphasis on key diagnostic features along with several, high quality annotated images. Emerging concepts are introduced throughout the article. These are referenced by the latest research to give the reader an update of current GI imaging in children.

TU‐G‐207‐00: Emerging Applications of X‐Ray Imaging

Last few years has witnessed the development of novel of X‐ray imaging modalities, such as spectral CT, phase contrast CT, and X‐ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X‐ray imaging modalities and update the attendees with knowledge in various related topics, including X‐ray photon‐counting detectors, X‐ray physics underlying the emerging applications beyond the traditional X‐ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X‐ray activatable targeted nanoparticles for molecular X‐ray imaging will be discussed in the context of X‐ray fluorescence and luminescence CT.Learning Objectives: Present background knowledge of various emerging X‐ray imaging techniques, such as spectral CT, phase contrast CT and X‐ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X‐ray imaging modalities. Describe utility and future impact of the new generation of X‐ray imaging applications.

TU‐G‐207‐01: CT Imaging Using Energy‐Sensitive Photon‐Counting Detectors

Last few years has witnessed the development of novel of X‐ray imaging modalities, such as spectral CT, phase contrast CT, and X‐ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X‐ray imaging modalities and update the attendees with knowledge in various related topics, including X‐ray photon‐counting detectors, X‐ray physics underlying the emerging applications beyond the traditional X‐ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X‐ray activatable targeted nanoparticles for molecular X‐ray imaging will be discussed in the context of X‐ray fluorescence and luminescence CT.Learning Objectives: Present background knowledge of various emerging X‐ray imaging techniques, such as spectral CT, phase contrast CT and X‐ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X‐ray imaging modalities. Describe utility and future impact of the new generation of X‐ray imaging applications.

TU‐G‐207‐03: High Spatial Resolution and High Sensitivity X‐Ray Fluorescence Imaging

Last few years has witnessed the development of novel of X‐ray imaging modalities, such as spectral CT, phase contrast CT, and X‐ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X‐ray imaging modalities and update the attendees with knowledge in various related topics, including X‐ray photon‐counting detectors, X‐ray physics underlying the emerging applications beyond the traditional X‐ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X‐ray activatable targeted nanoparticles for molecular X‐ray imaging will be discussed in the context of X‐ray fluorescence and luminescence CT.Learning Objectives: Present background knowledge of various emerging X‐ray imaging techniques, such as spectral CT, phase contrast CT and X‐ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X‐ray imaging modalities. Describe utility and future impact of the new generation of X‐ray imaging applications.

TU‐G‐207‐02: Clinical Applications of X‐Ray Phase Contrast Imaging: Where Do We Stand?

Last few years has witnessed the development of novel of X‐ray imaging modalities, such as spectral CT, phase contrast CT, and X‐ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X‐ray imaging modalities and update the attendees with knowledge in various related topics, including X‐ray photon‐counting detectors, X‐ray physics underlying the emerging applications beyond the traditional X‐ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X‐ray activatable targeted nanoparticles for molecular X‐ray imaging will be discussed in the context of X‐ray fluorescence and luminescence CT.Learning Objectives: Present background knowledge of various emerging X‐ray imaging techniques, such as spectral CT, phase contrast CT and X‐ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X‐ray imaging modalities. Describe utility and future impact of the new generation of X‐ray imaging applications.

Detection of the interface between two metals by eddy current thermography

The capability of eddy current thermography in detecting the interface between two (different) metals is investigated numerically. The simulations concern the detection of: (a) the boundary between two halves of a plate, each half made of a different material, and (b) the position and shape of a small region, consisting of a different material than the surrounding one. A simple observation of numerical snapshots (isotherms) gives only a vague indication about the interface; however, the numerical experiment results are improved considerably by data processing techniques, like image subtraction, and the depiction of the norm of the spatial derivatives of: (i) the instantaneous temperature and (ii) the mean value of temperature over a time period. The most effective technique proved to be the latter one, which determines the interface quite clearly, even in the case where the electrical and thermal properties of the two materials are similar. The sharpness of the interface depends on how dissimilar the two materials are, on the number of gradations in the temperature field (a function of the sensitivity of the infrared camera as well as the maximum increase in temperature within the work-piece), on the image update rate and on the time period over which the mean value of temperature is calculated. It depends also on the temperature distribution, which is affected by the exciting frequency. Higher exciting frequencies generate higher heating rates, but this does not ensure sharper images for the interface than those obtained by lower frequencies.

An Update of Clinical CT Imaging of Pancreatic Neoplasm: Tips, Tricks, and Pitfalls

The progressive advancement in computed tomography (CT) technology has enabled improved diagnosis and management of pancreatic tumors. Some of these improvements are seen in multidetector CT, dual-energy CT, perfusion CT, and post-processing techniques. Despite the technological improvement, prognosis for tumors such as pancreatic adenocarcinomas remains dismal. This review article will discuss some of the tips, tricks, and pitfalls for optimal utilization of these imaging techniques to characterize, diagnosis, and manage some of the more common pancreatic tumors such as adenocarcinomas, cystic tumors, and neuroendocrine tumors.

Accelerated statistical reconstruction for C-arm cone-beam CT using Nesterov's method.

To accelerate model-based iterative reconstruction (IR) methods for C-arm cone-beam CT (CBCT), thereby combining the benefits of improved image quality and/or reduced radiation dose with reconstruction times on the order of minutes rather than hours. The ordered-subsets, separable quadratic surrogates (OS-SQS) algorithm for solving the penalized-likelihood (PL) objective was modified to include Nesterov's method, which utilizes "momentum" from image updates of previous iterations to better inform the current iteration and provide significantly faster convergence. Reconstruction performance of an anthropomorphic head phantom was assessed on a benchtop CBCT system, followed by CBCT on a mobile C-arm, which provided typical levels of incomplete data, including lateral truncation. Additionally, a cadaveric torso that presented realistic soft-tissue and bony anatomy was imaged on the C-arm, and different projectors were assessed for reconstruction speed. Nesterov's method provided equivalent image quality to OS-SQS while reducing the reconstruction time by an order of magnitude (10.0 ×) by reducing the number of iterations required for convergence. The faster projectors were shown to produce similar levels of convergence as more accurate projectors and reduced the reconstruction time by another 5.3 ×. Despite the slower convergence of IR with truncated C-arm CBCT, comparison of PL reconstruction methods implemented on graphics processing units showed that reconstruction time was reduced from 106 min for the conventional OS-SQS method to as little as 2.0 min with Nesterov's method for a volumetric reconstruction of the head. In body imaging, reconstruction of the larger cadaveric torso was reduced from 159 min down to 3.3 min with Nesterov's method. The acceleration achieved through Nesterov's method combined with ordered subsets reduced IR times down to a few minutes. This improved compatibility with clinical workflow better enables broader adoption of IR in CBCT-guided procedures, with corresponding benefits in overcoming conventional limits of image quality at lower dose.