Medical Diagnostic Imaging Research Articles

CT Irradiation-induced Changes of Gene Expression within Peripheral Blood Cells.

Computed tomography (CT) is a crucial element of medical imaging diagnostics. The widespread application of this technology has made CT one of the major contributors to medical radiation burden, despite the fact that doses per individual CT scan steadily decrease due to the advancement of technology. Epidemiological risk assessment of CT exposure is hampered by the fact that moderate adverse effects triggered by low doses of CT exposure are likely masked by statistical fluctuations. In light of these limitations, there is need of further insights into the biological processes induced by CT scans to complement the existing knowledge base of risk assessment. This prompted us to investigate the early transcriptomic response of ex vivo irradiated peripheral blood of three healthy individuals. Samples were irradiated employing a modern dual-source-CT-scanner with a tube voltage of 150 kV, resulting in an estimated effective dose of 9.6 mSv. RNA was isolated 1 h and 6 h after exposure, respectively, and subsequently analyzed by RNA deep sequencing. Differential gene expression analysis revealed shared upregulation of AEN, FDXR, and DDB2 6 h after exposure in all three probands. All three genes have previously been discussed as radiation responsive genes and have already been implicated in DNA damage response and cell cycle control after DNA damage. In summary, we substantiated the usefulness of AEN, FDXR, and DDB2 as RNA markers of low dose irradiation. Moreover, the upregulation of genes associated with DNA damage reminds one of the genotoxic nature of CT diagnostics even with the low doses currently applied.

Three-Dimensional Block Matching Using Orthonormal Tree-Structured Haar Transform for Multichannel Images.

Multichannel images, i.e., images of the same object or scene taken in different spectral bands or with different imaging modalities/settings, are common in many applications. For example, multispectral images contain several wavelength bands and hence, have richer information than color images. Multichannel magnetic resonance imaging and multichannel computed tomography images are common in medical imaging diagnostics, and multimodal images are also routinely used in art investigation. All the methods for grayscale images can be applied to multichannel images by processing each channel/band separately. However, it requires vast computational time, especially for the task of searching for overlapping patches similar to a given query patch. To address this problem, we propose a three-dimensional orthonormal tree-structured Haar transform (3D-OTSHT) targeting fast full search equivalent for three-dimensional block matching in multichannel images. The use of a three-dimensional integral image significantly saves time to obtain the 3D-OTSHT coefficients. We demonstrate superior performance of the proposed block matching.

AI-based computer-aided diagnosis (AI-CAD): The latest review to read first

The third artificial intelligence (AI) boom is coming, and there is an inkling that the speed of its evolution is quickly increasing. In games like chess, shogi, and go, AI has already defeated human champions, and the fact that it is able to achieve autonomous driving is also being realized. Under these circumstances, AI has evolved and diversified at a remarkable pace in medical diagnosis, especially in diagnostic imaging. Therefore, this commentary focuses on AI in medical diagnostic imaging and explains the recent development trends and practical applications of computer-aided detection/diagnosis using artificial intelligence, especially deep learning technology, as well as some topics surrounding it.

High-performance potassium sodium niobate piezoceramics for ultrasonic transducer

Ultrasonic transducers can be used as medical diagnostic imaging and nondestructive testing. This work presents phase structure engineered high-performance potassium sodium niobate [(K,Na)NbO3, KNN]-based ceramics and its potential application on ultrasonic transducer. A connection among structural engineering, electrical properties, and prototype device designing was established in lead-free KNN-based ceramics. Structural elucidation through atomic resolution polarization mapping by Z-contrast imaging indicates that the nanoscale balanced multiple phase coexistence (R-O-T) is the origin of both enhanced piezoelectricity and improved temperature stability: high d33 of 500 pC/N and improved in-situ temperature stability of d33 (less than 24% variation for d33 from 25 to 100 °C), together with the improvement of electromechanical coupling coefficient (kp~0.5 and kt~0.55). Based on the high-performance ceramics, a 1–3 composite ultrasonic transducer with a center frequency of 5 MHz is produced, and a bandwidth of 81% at −6 dB is substantially higher than that of PZT-based transducers at the same center frequency. We believe the novel way to improve electrical properties through structural engineering could open a new road to promote the practical application of KNN-based ceramics.

Robust 2D/3D multi-polar acoustic metamaterials with broadband double negativity

Acoustic negative-index metamaterials show promise in achieving superlensing for diagnostic medical imaging. In spite of the recent progress made in this field, most acoustic metamaterials (AMMs) suffer from deficiencies such as low spatial symmetry, sophisticated labyrinth topologies and narrow-band features, which hamper their applications for symmetric subwavelength imaging. To overcome the hurdle of designing practical negative-index metamaterials, in this paper, we propose a novel category of robust multi-cavity metamaterials and reveal their common double-negative mechanism enabled by multi-polar (dipole, quadrupole and octupole) resonances in both two-dimensional (2D) and three-dimensional (3D) scenarios. In particular, we discover explicit relationships governing the double-negative frequency bounds from equivalent circuit analogy. For the first time, we construct a simple, highly-symmetric and intuitionistic 3D AMM by exploiting the multi-cavity topological features. This entails the broadband single-source and double-source subwavelength imaging, which is demonstrated and verified by 2D and 3D superlens both numerically and experimentally. Moreover, the analogical 3D superlens can ensure the subwavelength imaging in all directions. The proposed multi-polar resonance-enabled robust metamaterials and design methodology open horizons for easier manipulation of subwavelength waves and realization of practical 3D metamaterial devices.

Assessment of the Awareness and Attitude of Emergency Physicians towards the use of Computed Tomography in patients with head injury in various hospitals in Anambra State, Nigeria

The use of x-ray and computed tomography scan is critical in the management of traumatic conditions, particularly head injuries. This study was carried out to assess the level of awareness and attitude of Emergency physicians towards the use of CT in cases of head injury. A cross-sectional study was done among emergency physicians working in five different government hospitals in Anambra State. Among the respondents were 29% males and 4% females: mean age was 35.7 years while their modal age was 31-40 years. All the respondents, 33 (100%) stated they find CT scan as a useful diagnostic medical imaging modality. However less than half of them, 15 (45.5%) stated they refer patients for CT scan for those patients that need it. Whereas most of them, 20 (64.5%) stated that head injury patients should undergo both X-Ray and CT scan virtually all of them 32 (97%), responded that computed tomography, (CT) is better than skull x-ray in the examination of head injury. Though majority of the respondents 31 (93%), stated that CT scan subject the patient to some risks. All those who responded and thought that CT scan should continue to be used as medical diagnostic imaging modality were 33 (100%). The result of the study showed that most of the emergency physicians are aware of the usefulness of CT in the examination of patients presenting with head injury, but the non- availability and cost of services of the CT imaging equipment greatly affected the rate of request for the examination and has affected their attitude towards the use of this imaging modality in the examination of this category of patients in need of it.

Uncertainty Assessment of Quantitative Measurements in Medical Imaging: Applications in Cross-Sectional and Longitudinal Diffusion MRI

The article's abstract is no available.

AI-based computer-aided diagnosis (AI-CAD): the latest review to read first.

The third artificial intelligence (AI) boom is coming, and there is an inkling that the speed of its evolution is quickly increasing. In games like chess, shogi, and go, AI has already defeated human champions, and the fact that it is able to achieve autonomous driving is also being realized. Under these circumstances, AI has evolved and diversified at a remarkable pace in medical diagnosis, especially in diagnostic imaging. Therefore, this commentary focuses on AI in medical diagnostic imaging and explains the recent development trends and practical applications of computer-aided detection/diagnosis using artificial intelligence, especially deep learning technology, as well as some topics surrounding it.

Preparation of high-efficiency near-infrared aggregation-induced emission nanoparticles based on FRET and their use in bio-imaging

Recently, the development of fluorescent probes has contributed to significant advances in cell biology and medical diagnostic imaging. In this work, we use biocompatible bovine hemoglobin (BHb) molecules to co-coat aggregation-induced emission (AIE) molecules amino tetraphenylethylene (TPE-NH2) and near-infrared emission molecules 2-(4-aminophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl) fumaronitrile (TPAADFN), to get TPE-NH2/TPAADFN@BHb nanoparticles. Due to the fluorescence resonance energy transfer (FRET) between the two fluorescent molecules, the prepared fluorescent nanoparticles have high fluorescence quantum efficiency. The prepared TPE-NH2/TPAADFN@BHb nanoparticles also have large Stokes shift, which helps to avoid the cross-talk between the absorption and emission of the particles themselves. This is beneficial to avoid the self-absorption of biological tissues and obtain very high detection sensitivity. Furthermore, due to the good biocompatibility of BHb, TPE-NH2/TPAADFN@BHb nanoparticles have good mono-dispersity, low toxicity and high brightness, which is very propitious in the application of bio-imaging.

Multidetector computed tomography in the diagnosis and staging of renal trauma

Background In cases of renal trauma with stable general condition of the patient, contrast-enhanced computed tomography (CECT) is preferred for examination. In addition to a rapid intervention, most of the important data related to parenchymal injury degree are provided with or without inclusion of pelvicalcyeal system (PCS) and injuries of renal blood vessels. Aim of the study This study focuses on the assessment of the impact of different multidetector computed tomography (MDCT) phases in the diagnosis and staging of renal trauma either of blunt or penetrating cause. Patients and methods This prospective study was carried out on 20 patients, ranging in age between 5 and 55 years, clinically suspected to have renal trauma, referred from the Urology Department and Outpatient Clinics to the Diagnostic Radiology and Medical Imaging Department in Tanta University Hospitals for MDCT examination. Results In terms of vascular injury, 17 patients (85%) had no vascular injury and 3 patients had vascular injury (15%). Nine patients (45%) had grade IV vascular injury and six patients had grade III vascular injury (30%), grade I and II vascular injury was present in two patients each (10%) and grade V vascular injury was present in only one patient (5%). Conclusion CECT is the most preferred method for assessment of renal trauma and other associated injuries; most of the important data related to parenchymal injury degree are provided with or without inclusion of PCS and injuries of renal blood vessels with a sensitivity of 90–100%.

Reduction of Speckle Noise and Image Enhancement in Ultrasound Image Using Filtering Technique and Edge Detection

Ultrasound (US) imaging application in medicine and other fields is enormous. It has several advantages over other medical imaging modalities. The use of US in diagnosis is well established because of its noninvasive nature, portable, accurate, low-cost imaging modality, capable of forming real-time imaging and continuing improvement in image quality. Medical images and satellite images are usually degraded by noise during image acquisition and transmission process. It is estimated that 1 out of every form medical diagnostic image studies in the world involves ultrasonic techniques. The objectives of this article are to give an overview of the types of speckle reduction techniques in US imaging, present a new technique of speckle reduction, and carry out a comparative evaluation of despeckle filtering based on image quality metrics. A new speckle suppression method and coherence enhancement of medical US image are proposed: 9 despeckled filtering techniques and 5 edge detection operators, with the result evaluated by image quality metrics. The best edge detection hybrid with best filter, quality evaluation metrics has been found that the proposed method performance better than all other methods, while the structural details and result preserving of small and important image feature that contain diagnostic information in a better way than other despeckling filter.

Mobile MIM: a Portable Solution in Imaging.

Clinicians experience various situations, such as peer consultation or tumor boards, in which they need to access and view radiologic studies without a full radiologic workstation. Mobile MIM is a diagnostic medical imaging device on the Apple App Store that is FDA-approved and can meet the portable needs of clinicians. The goal of the app is to give physicians the opportunity to visualize scans from multiple modalities on a single iOS mobile device. The intended uses include reviewing complex aspects of radiation treatment plans and analyzing medical images from a wide array of modalities. The key limitation is incompatibility for mammography. The free app allows users to manipulate image sets from ten sample patients before an organization can commit to extensive systems integration with MIMcloud 2.0 to store, encrypt, and route image sets for real-time patients. This review explores the app's strengths and weaknesses through discussion of its features and usability.

Deep Learning and Artificial Intelligence for the Determination of the Cervical Vertebra Maturation Degree from Lateral Radiography

Deep Learning (DL) and Artificial Intelligence (AI) tools have shown great success in different areas of medical diagnostics. In this paper, we show another success in orthodontics. In orthodontics, the right treatment timing of many actions and operations is crucial because many environmental and genetic conditions may modify jaw growth. The stage of growth is related to the Cervical Vertebra Maturation (CVM) degree. Thus, determining the CVM to determine the suitable timing of the treatment is important. In orthodontics, lateral X-ray radiography is used to determine it. Many classical methods need knowledge and time to look and identify some features. Nowadays, ML and AI tools are used for many medical and biological diagnostic imaging. This paper reports on the development of a Deep Learning (DL) Convolutional Neural Network (CNN) method to determine (directly from images) the degree of maturation of CVM classified in six degrees. The results show the performances of the proposed method in different contexts with different number of images for training, evaluation and testing and different pre-processing of these images. The proposed model and method are validated by cross validation. The implemented software is almost ready for use by orthodontists.

Grayscale-to-Color: Scalable Fabrication of Custom Multispectral Filter Arrays

Snapshot multispectral image (MSI) sensors have been proposed as a key enabler for a plethora of multispectral imaging applications, from diagnostic medical imaging to remote sensing. With each application requiring a different set, and number, of spectral bands, the absence of a scalable, cost-effective manufacturing solution for custom multispectral filter arrays (MSFAs) has prevented widespread MSI adoption. Despite recent nanophotonic-based efforts, such as plasmonic or high-index metasurface arrays, large-area MSFA manufacturing still consists of many-layer dielectric (Fabry–Perot) stacks, requiring separate complex lithography steps for each spectral band and multiple material compositions for each. It is an expensive, cumbersome, and inflexible undertaking, but yields optimal optical performance. Here, we demonstrate a manufacturing process that enables cost-effective wafer-level fabrication of custom MSFAs in a single lithographic step, maintaining high efficiencies (∼75%) and narrow line widths (∼25 nm) across the visible to near-infrared. By merging grayscale (analog) lithography with metal–insulator–metal (MIM) Fabry–Perot cavities, whereby exposure dose controls cavity thickness, we demonstrate simplified fabrication of MSFAs up to N-wavelength bands. The concept is first proven using low-volume electron beam lithography, followed by the demonstration of large-volume UV mask-based photolithography with MSFAs produced at the wafer level. Our framework provides an attractive alternative to conventional MSFA manufacture and metasurface-based spectral filters by reducing both fabrication complexity and cost of these intricate optical devices, while increasing customizability.

A multi E x B filter system for isotope enrichment application

The design of a special type E x B (or “Wien”) filter for efficient isotope separation is described. Computation results demonstrated that an optimized E x B filter can produce highly enriched isotopes such as 10B, 98Mo, and 100Mo which are useful for the manufacturing of radioactive isotopes for medical diagnostic imaging studies and therapeutic applications. Using the ion beams generated by a large area RF-driven plasma source, it is shown that a multi E x B filter system can greatly enhance the yield of a range of commercially desirable isotopes.

Vascular ring anomalies in cats: 20 cases (2000-2018).

To report the clinical characteristics, types of vascular ring anomalies (VRA), operative findings, complications, and survival after surgical treatment of cats with VRA. Retrospective, multi-institutional case series. Client- or shelter-owned cats presenting to academic, referral veterinary institutions. Medical records of cats with VRA that underwent surgical treatment were reviewed. Signalment, relevant medical history, clinical signs, diagnostic imaging, surgical findings, complications, and survival were recorded. Twenty cats with VRA were included. Vascular ring anomalies were most commonly (75% [15/20]) diagnosed in cats less than 1 year old, with no breed or sex predilection. Regurgitation was the most common clinical sign, present in 18 of 20 (90%) cats. A persistent right aortic arch was diagnosed in 17 of 20 (85%) cats, with concurrent aberrant left subclavian artery in four of the cats. Surgical treatment was associated with survival to discharge in 18 of 20 (90%) cats. Persistent clinical signs were reported in nine of 13 (69%) cats, and radiographic evidence of megaesophagus persisted in four of 13 (31%) cats, with a median follow-up of 275 days after discharge. Persistent right aortic arch was the most commonly diagnosed VRA in cats in this series, although multiple anomalies were observed. Surgical treatment of VRA in cats was associated with a high survival to discharge, although persistence of clinical signs and megaesophagus was noted in 69% and 31% of the cats, respectively. Surgical treatment of VRA in cats is associated with a high survival rate; however, persistence of clinical signs is an expected outcome.

Advanced Deep Learning Embedded Motion Radiomics Pipeline for Predicting Anti-PD-1/PD-L1 Immunotherapy Response in the Treatment of Bladder Cancer: Preliminary Results

A key objective of modern medicine is precision medicine, whose purpose is to personalize the treatment based on the specific characteristics of the patients and their illness. To guide treatment decisions, it is generally necessary to have a sample of the neoplastic tissue, which is obtained only with biopsies or similar invasive surgical procedures. As tumors are heterogeneous in their volume and change over time, a dynamic analysis of diagnostic medical images can provide a better understanding of the entire tumor, both in the screening and follow-up phase. In this work, the authors proposed the use of a radiomics pipeline which is able to characterize the possible response of the oncological patients to the anti- programmed death-ligand protein 1 (PD-L1) immunotherapeutic treatment. The immunotherapeutic treatment consists of a modern therapeutic approach in which the physicians try to reactivate the patient's immune system so that it recognizes and destroys cancer cells. The oncological biomarkers capable of characterizing patients who can benefit from immunotherapy from those who would not, are being studied. One of them is related to the expression of the PD-L1 inhibitor in the surface of neoplastic cells which are analyzed in this paper, considering that the analyzed immunotherapeutic treatment is of the anti-PD-L1 type. In this context, the authors propose a pipeline for an immunotherapy response prediction based on the analysis of only CT-scan images of patients with metastatic bladder cancer. Using a framework based on the use of deep Autoeconder network, CT-scan images were analyzed to extract the features capable of discriminating the patient's response to anti-PD-L1 immunotherapy treatment from those who are not. The preliminary results obtained (accuracy of approximately 86% with a sensitivity of approximately 80% against a specificity of approximately 89%) on the analyzed patient dataset, allows the confirmation of the feasibility of the proposed method. Although validated in a dataset containing patients with only one tumor histology (bladder cancer), the proposed method shows how modern radiomics techniques can contribute significantly in the implementation of non-invasive predictive systems that support the physician in the therapeutic choice. The idea of the authors is to create a form of oncological point of care on an embedded platform that allows physicians to always have a support tool in choosing the best therapy to suggest to the patient.

Demonstration of multiple contrast agent imaging for the next generation color X-ray CT

X-ray computed tomography (CT) is widely used for non-invasive diagnostic imaging of the inside of the human body. It should be noted that the approximate effective radiation dose in a patient is 10 mSv. Under such an environment, X-ray photons are severely piled-up. Therefore, conventional CT only reconstructs energy integrated image, which may consist of beam hardening artifacts that have proven to be a problem. In contrast, photon counting CT (PC-CT) offers a low-dose multicolor CT imaging. The PC-CT also enables K-edge imaging that can improve the blood–tissue contrast using specific contrast agents. Moreover, the PC-CT has great advantages in (1) the simultaneous imaging of multiple contrast agents, and (2) the absolute quantification of contrast agents. Owing to these advantages, the PC-CT system can provide more detailed tissue diagnosis than conventional CT systems. Recently, we proposed a novel PC-CT system (Morita et al., 2017; Arimoto et al., 2017, Maruhashi et al., 2018) consisting of multipixel photon counter (MPPC) coupled with a high-speed scintillator, which is a cost-effective and easy to assemble system, as compared to other PC-CT devices based on cadmium zinc telluride. In this paper, we operated the K-edge imaging of specific contrast agents using a 16-channel MPPC PC-CT system. Our PC-CT system established appropriate energy thresholds and operated the simultaneous imaging of multiple contrast agents such as iodine and gadolinium. In addition, we estimated the absolute concentration of these contrast agents. The results show that our PC-CT system can provide more accurate diagnostic medical imaging, as compared to the conventional CT system.

Anomalous water dynamics in brain: a combined diffusion magnetic resonance imaging and neutron scattering investigation.

Water diffusion is an optimal tool for investigating the architecture of brain tissue on which modern medical diagnostic imaging techniques rely. However, intrinsic tissue heterogeneity causes systematic deviations from pure free-water diffusion behaviour. To date, numerous theoretical and empirical approaches have been proposed to explain the non-Gaussian profile of this process. The aim of this work is to shed light on the physics piloting water diffusion in brain tissue at the micrometre-to-atomic scale. Combined diffusion magnetic resonance imaging and first pioneering neutron scattering experiments on bovine brain tissue have been performed in order to probe diffusion distances up to macromolecular separation. The coexistence of free-like and confined water populations in brain tissue extracted from a bovine right hemisphere has been revealed at the micrometre and atomic scale. The results are relevant for improving the modelling of the physics driving intra- and extracellular water diffusion in brain, with evident benefit for the diffusion magnetic resonance imaging technique, nowadays widely used to diagnose, at the micrometre scale, brain diseases such as ischemia and tumours.

The Radiation Safety Officer as an Advocate for Patient Safety.

The role of the radiation safety officer is to maintain radiation exposures as low as reasonably achievable. Traditionally, the focus has been on reducing or eliminating unnecessary occupational exposure to employees and ensuring exposure of visitors and members of the public is maintained below regulatory limits. Over the last three decades there has been increasing concern expressed in the medical literature on the potential risks of radiation exposure to patients undergoing diagnostic medical imaging procedures. This paper will discuss the need for advocacy and processes by which the radiation safety officer can expand the focus of a medical radiation safety program to include advocacy for applying the principles and practices of maintaining exposures as low as reasonably achievable to patients.