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The aim of this study was to investigate the incidence of juxta-apical radiolucency (JAR) and its relations with surrounding structures using cone-beam computed tomography (CT). A total of 215 cone-beam CT images was analysed retrospectively to record the presence, site, and size of the JAR, and the relations between the JAR and the mandibular canal, buccal or lingual cortical plates, tooth position, and condition of root apex. Descriptive analyses were made, and relations between the categorical variables were tested with the chi squared test. JAR was detected in 71 (33%) (5 bilateral and 66 unilateral) of 215 patients (378 mandibular third molars) on cone-beam CT images. It was most commonly seen mesial to the tooth (43%) and above the third molars (55%), and was least common lingual to the tooth (3%) and at the distoangular third molar (3%) (p = 0.005). There was no significant relation between the JAR and the mandibular canal, but JAR was most likely to be detected superiorly to the mandibular canal (59% of cases). JAR can be seen and evaluated with cone-beam CT. It was most commonly seen mesial to the tooth and above the third molar. No significant relation was found between JAR and the mandibular canal, cortical plate, or condition of the apex. Future studies on the assessment of JAR should be done with a larger sample size as prospective cone-beam CT studies. (C) 2019 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

INTRODUCTION Traumatic brain injury (TBI) is a common reason for pediatric emergency room visits. Surgical intervention for mild TBI is rarely necessary in children aged

OBJECTIVE: To develop a deep convolutional neural network (CNN) to automatically segment an axial CT image of the pelvis for body composition measures. We hypothesized that a deep CNN approach would achieve high accuracy when compared to manual segmentations as the reference standard.MATERIALS AND METHODS: We manually segmented 200 axial CT images at the supra-acetabular level in 200 subjects, labeling background, subcutaneous adipose tissue (SAT), muscle, inter-muscular adipose tissue (IMAT), bone, and miscellaneous intra-pelvic content. The dataset was randomly divided into training (180/200) and test (20/200) datasets. Data augmentation was utilized to enlarge the training dataset and all images underwent preprocessing with histogram equalization. Our model was trained for 50 epochs using the U-Net architecture with batch size of 8, learning rate of 0.0001, Adadelta optimizer and a dropout of 0.20. The Dice (F1) score was used to assess similarity between the manual segmentations and the CNN predicted segmentations.RESULTS: The CNN model with data augmentation of N = 3000 achieved accurate segmentation of body composition for all classes. The Dice scores were as follows: background (1.00), miscellaneous intra-pelvic content (0.98), SAT (0.97), muscle (0.95), IMAT (0.91), and bone (0.92). Mean time to automatically segment one CT image was 0.07 s (GPU) and 2.51 s (CPU).CONCLUSIONS: Our CNN-based model enables accurate automated segmentation of multiple tissues on pelvic CT images, with promising implications for body composition studies.

We present an interpretable end-to-end computer-aided detection and diagnosis tool for pulmonary nodules on computed tomography (CT) using deep learning-based methods. The proposed network consists of a nodule detector and a nodule malignancy classifier. We used RetinaNet to train a nodule detector using 7,607 slices containing 4,234 nodule annotations and validated it using 2,323 slices containing 1,454 nodule annotations drawn from the LIDC-IDRI dataset. The average precision for the nodule class in the validation set reached 0.24 at an intersection over union (IoU) of 0.5. The trained nodule detector was externally validated using a UCLA dataset. We then used a hierarchical semantic convolutional neural network (HSCNN) to classify whether a nodule was benign or malignant and generate semantic (radiologist-interpretable) features (e.g., mean diameter, consistency, margin), training the model on 149 cases with diagnostic CTs collected from the same UCLA dataset. A total of 149 nodule-centered patches from the UCLA dataset were used to train the HSCNN. Using 5-fold cross validation and data augmentation, the mean AUC and mean accuracy in the validation set for predicting nodule malignancy achieved 0.89 and 0.74, respectively. Meanwhile, the mean accuracy for predicting nodule mean diameter, consistency, and margin were 0.59, 0.74, and 0.75, respectively. We have developed an initial end-to-end pipeline that automatically detects nodules ≥ 5 mm on CT studies and labels identified nodules with radiologist-interpreted features automatically.

This paper presents the results of the development of a three-dimensional refined electrodynamic model of the human chest and internal organs for various age groups. As the initial data, the results of statistical analysis of the data obtained during MRI and CT studies of patients of various age groups were used. The aim of the work is to determine the minimum allowable detailing of the chest organs for the further development of experimental phantoms for research of various diagnostic and treatment methods, as well as devices operating in the vicinity of the human body to simulate their functioning in conditions close to real ones and determine their effects on humans. This model is designed for analyzing the propagation of microwave electromagnetic waves in the chest taking into account the presence of organs and tissues. The results of modeling the propagation of electromagnetic waves of various frequencies through the human chest in the presence of internal organs and bones are presented.

The continuous development of SPECT over the past 50 years has led to improved image quality and increased diagnostic confidence. The most influential developments include the realization of hybrid SPECT/CT devices, as well as the implementation of attenuation correction and iterative image reconstruction techniques. These developments have led to a preference for SPECT/CT devices over SPECT-only systems and to the widespread adoption of the former, strengthening the role of SPECT/CT as the workhorse of Nuclear Medicine imaging. New trends in the ongoing development of SPECT/CT are diverse. For example, whole-body SPECT/CT images, consisting of acquisitions from multiple consecutive bed positions in the manner of PET/CT, are increasingly performed. Additionally, in recent years, some interesting approaches in detector technology have found their way into commercial products. For example, some SPECT cameras dedicated to specific organs employ semiconductor detectors made of cadmium telluride or cadmium zinc telluride, which have been shown to increase the obtainable image quality by offering a higher sensitivity and energy resolution. However, the advent of quantitative SPECT/CT which, like PET, can quantify the amount of tracer in terms of Bq/mL or as a standardized uptake value could be regarded as most important development. It is a major innovation that will lead to increased diagnostic accuracy and confidence, especially in longitudinal studies and in the monitoring of treatment response. The current work comprises two main aspects. At first, physical and technical fundamentals of SPECT image formation are described and necessary prerequisites of quantitative SPECT/CT are reviewed. Additionally, the typically achievable quantitative accuracy based on reports from the literature is given. Second, an extensive list of studies reporting on clinical applications of quantitative SPECT/CT is provided and reviewed.

Recent progress in image diagnosis technology enables us to detect numerous new findings for the diagnosis of ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF). In most cases of cervical OPLL and thoracic OPLL/OLF, not only static compression, but also dynamic factors contribute to the development and aggravation of the myelopathy. The rationale for posterior decompression and fusion (PDF) surgery is to suppress the motion at the nonossified segment of OPLL by stabilization. The K-line is a simple and practical parameter with utility for decisions regarding the surgical approach to cervical OPLL. Sufficient posterior shift of the spinal cord and neurological improvement will not be obtained after laminoplasty in K-line (−) OPLL patients. Multicenter CT studies of ossification of the spinal ligament have been performed by the Japanese Research Group for Ossification of the Spinal Ligament to evaluate the prevalence of OPLL in the whole spine.

Pathological changes in the vertebral column of farmed Atlantic salmon in Norway have been reported since the 1990s. Based on the characteristic radiographic findings, we here present a vertebral column deformity named "curved cross-stitch vertebrae" that mainly affects the middle aspect of the vertebral column. Sixty fish, from the west/northwest coast of mid-Norway, were sampled at slaughter and examined by radiography, computed tomography (CT), necropsy, macrophotography, and histology. The vertebral deformities were radiographically graded as mild, moderate, or marked. The main differences between these grades of changes were defined by increased curving of the peripheries of endplates, reduced intervertebral spaces, and vertical displacement of the vertebrae. The curved rims of endplates were located peripheral to a continuous and approximately circular borderline. The CT studies revealed small, multifocal, hypo-attenuating, round to crescent-shaped areas in the notochord, compatible with the presence of gas. Additionally, histology revealed that the axial parts of endplates had circular zones with perforations, through which either notochordal tissue prolapsed into the vertebrae or vascularized fibrochondroid proliferations extended from the vertebrae into the notochord. Inflammation was present in many vertebral bodies. To the best of our knowledge, this is the first report of gas in the notochord of fish.

Metallic cellular solids are a class of materials known for their high specific mechanical properties, being desirable in applications where a combination of high strength or stiffness and low density are important. These lightweight materials are often stochastic and manufactured by foaming or casting. If regular (periodic) lattice structures are desired, they may be manufactured by metallic additive manufacturing techniques. However, these have characteristic issues, such as un-melted powders, porosity and heterogeneous microstructures. This study reports a novel low-cost route for producing regular lattice structures by an additive manufacturing assisted investment casting technique. Fused filament fabrication is used to produce the lattice structure pattern which is infiltrated with plaster. The pattern is then burnt off and the aluminum is cast in vacuum. In this way we can manufacture non-stochastic metallic lattices having fine struts/ribs (0.6mm cross-section using a 0.4mm nozzle) and relative densities down to 0.036. X-ray micro computed tomography (μCT) showed that as-cast A356 Aluminium alloy frameworks have high dimensional tolerances and fine detail control. Frameworks based on units of six connected struts ranging from intruding (auxetic) to protruding (hexagonal) strut angles are studied. Vertical struts are finer than expected, reducing their moment of area which could impact their compressive strength. This new, low cost, route for producing high precision metallic cellular lattices offers an attractive alternative to other additive manufacturing techniques (e.g. selective laser and electron beam melting)., European Research Council through the ERC grant CORREL-CT, number 695638 to enable VHC to visit the Henry Royce Institute to undertake the X-ray CT studies. This work was supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X/1, EP/S019367/1, EP/P025021/1 and EP/P025498/1. Also, this work was supported by Portuguese FCT, under the reference project UIDB/04436/2020. project iRAIL Innovation in Railway Systems and Technologies Doctoral Programme funds and by national funds through FCT - Portuguese Foundation for Science and Technology and was developed on the aim of the Doctoral grant PD/ BD/114096/2015.

Atlanto-occipital dissociations secured the #1 pole position for CVJ abnormalities because these injuries seriously threaten the adjacent critical neurovascular structures and life itself with atlanto-occipital dislocation usually being fatal. Definition: Traumatic dislocation of the craniovertebral junction involves disruption of strong ligamentous attachments holding the atlas, axis, and occiput together. Atlanto-occipital dissociations (AODs) are severe injuries which include atlanto-occipital dislocation and atlanto-occipital subluxation. The Classic Clue section reminds us when the trauma service requests head and neck imaging of patient who received multiple traumas as a pedestrian hit by a motor vehicle, who continues to complain of neck pain, although “no fracture” was identified on examination at the outside hospital which treated the patients other not insignificant injuries. AOD is often difficult to diagnose on initial imaging studies. Normal measurements for CT studies are distinctly different than for plain films, particularly in children. If you even suspect a problem, get a CT. AOD is a rare medical condition accounting for ~1% of cervical spine injuries but ~15% of fatal spine trauma. AOD is more common in children, probably because their small, horizontally oriented occipital condyles, the flat surface of the C1 lateral masses, and a relatively “loose” ligamentous capsule.

The four-dimensional (4D) CT protocol uses pre-contrast, arterial, and venous phases rendered in all three planes with high spatial resolution sections that are 1–2 mm thick. The fourth dimension is enhancement change over time. Axial, sagittal, and coronal sections 1 mm thick are generated from all the runs. Parathyroid tissue has prominent arterial phase enhancement and good venous washout.

OBJECTIVES To use the mDIXON-Quant sequence to quantify the fat fraction of adrenal lesions discovered incidentally on CT studies. To analyze the relation between the signal loss between in-phase and out-of-phase T1-weighted sequences and the fat fraction in mDIXON-Quant. To compare the sensitivity and specificity of the two methods for characterizing adrenal lesions. MATERIAL AND METHODS This prospective descriptive study included 31 patients with incidentally discovered adrenal lesions evaluated with 3T MRI using in-phase and out-of-phase T1-weighted sequences and mDIXON-Quant; the fat fraction of the adrenal lesions was measured by mDIXON-Quant and by calculating the percentage of signal loss between in-phase and out-of-phase T1-weighted sequences. RESULTS The percentage of signal loss was significantly higher in the group of patients with adenoma (61.3% ± 20.4% vs. 5.1% ± 5.8% in the group without adenoma, p

Purpose: To study interreader variability for classifying pulmonary opacities at CT as perifissural nodules (PFNs) and determine how reliably radiologists differentiate PFNs from malignancies. Materials and Methods: CT studies were obtained retrospectively from the National Lung Screening Trial (2002-2009). Nodules were eligible for the study if they were noncalcified, solid, within the size range of 5 to 10 mm, and scanned with a section thickness of 2 mm or less. Six radiologists classified 359 nodules in a cancer-enriched data set as PFN, non-PFN, or not applicable. Nodules classified as not applicable by at least three radiologists were excluded, leaving 316 nodules for post-hoc statistical analysis. Results: The study group contained 22.2% cancers (70 of 316). The median proportion of nodules classified as PFNs was 45.6% (144 of 316). All six radiologists uniformly classified 17.7% (56 of 316) of the nodules as PFNs. The Fleiss k was 0.50. Compared with non-PFNs, nodules classified as PFNs were smaller and more often located in the lower lobes and attached to a fissure (P , .001). Thirteen (18.6%) of 70 cancers were misclassified 21 times as PFNs. Individual readers' misclassification rates ranged from 0% (0 of 125) to 4.9% (eight of 163). Of 13 misclassified malignancies, 11 were in the upper lobes and two were attached to a fissure. Conclusion: There was moderate interreader agreement when classifying nodules as perifissural nodules. Less than 2.5% of perifissural nodule classifications were misclassified lung cancers (21 of 865) in this cancer-enriched study. Allowing nodules classified as perifissural nodules to be omitted from additional follow-up in a screening setting could substantially reduce the number of unnecessary scans; excluding perifissural nodules in the upper lobes would greatly decrease the misclassification rate.

Sandstone exists widely in nature. The good permeability of hydrous sandstone makes it prone to collapse, which can cause natural disasters. Hence, studies into damage assessment of hydrous sandstone are crucial. Moisture is an important factor in sandstone structural damage. The major damage assessment methods of hydrous sandstone at present cannot satisfy real-time and portability requirements. In this study, acoustic emission (AE), computed tomography (CT), and electroencephalogram (EEG) techniques are combined for real-time damage assessment of hydrous sandstone. First, a real geotechnical engineering environment is simulated, and the AE signal stimulated from hydrous sandstone under gradually changing loading is analyzed. A mapping method of AE and moisture is proposed using the support vector machine algorithm. Second, a comprehensive damage assessment method is developed based on the CT technique. The mapping rule between moisture and damage level is determined through a model experiment. Third, a real-time damage assessment function of hydrous sandstone is proposed by considering two pieces of information: the assessment level of single AE, which varies with time, and the superposition effect of many AE events. Lastly, eight visual colors for warning are screened according to different damage states, and an EEG experiment is conducted to demonstrate their diverse excitations of the human brain's concentration.

To make quantitative methods of nuclear medicine more available, four centres in Croatia participated in the national intercomparison study, following the materials and methods used in the previous international study organized by the International Atomic Energy Agency (IAEA). The study task was to calculate the activities of four Ba sources (T 1/2=10.54 years; E γ=356 keV) using planar and single-photon emission computed tomography (SPECT) or SPECT/CT acquisitions of the sources inside a water-filled cylindrical phantom. The sources were previously calibrated by the US National Institute of Standards and Technology. Triple-energy window was utilized for scatter correction. Planar studies were corrected for attenuation correction (AC) using the conjugate-view method. For SPECT/CT studies, data from X-ray computed tomography were used for attenuation correction (CT-AC), whereas for SPECT-only acquisition, the Chang-AC method was applied. Using the lessons learned from the IAEA study, data were acquired according to the harmonized data acquisition protocol, and the acquired images were then processed using centralized data analysis. The accuracy of the activity quantification was evaluated as the ratio R between the calculated activity and the value obtained from National Institute of Standards and Technology. For planar studies, R=1.06±0.08; for SPECT/CT study using CT-AC, R=1.00±0.08; and for Chang-AC, R=0.89±0.12. The results are in accordance with those obtained within the larger IAEA study and confirm that SPECT/CT method is the most appropriate for accurate activity quantification.

The thermal effects on micro-properties of granite were experimentally studied. The volumetric porosity was observed by the X-ray Computed Tomography (CT) technique and three-dimensional (3D) image reconstruction. Two indexes (heterogeneity coefficient and anisotropy coefficient) were proposed to describe the micro-properties of granite. The thermal effects on these two indexes were discussed. The results shows that micro-porosity increases as temperature increases between 400 °C and 800 °C. It is slightly influenced by temperature beyond this range. Both of the heterogeneity and anisotropy of thermal treated granite increase to their maximums as temperature increases to 500 °C, than decrease to constants as temperature further increases. The heterogeneity and anisotropy of granite are mainly dominated by the initial cracks below 200 °C. The thermal induced cracks are mainly in the regions of lower density mineral grains below 400 °C. Boundary cracks and trans-granular cracks generate significantly above 500 °C.

This study investigates critical thinking (CT) studies in e-learning settings to provide a comprehensive analysis of CT studies. Research indexed in the Web of Science database which includes major...

Aim and objectives The aim of this study was to assess the role of 18-F FDG-PET/CT in evaluating the peripheral malignant neuronal affection as well as perineural tumoral spread that occurs in patients with cancers. Methodology 50 patients with clinical symptoms of neurological deficits (34 male and 16 female) were included, their ages ranged from 17 to 74 with a mean of 45 years. PET/CT was done for all patients followed by clinical correlation after anti-inflammatory drugs and chemotherapy. Results Interpretation of the PET/CT studies and clinical correlation revealed 10 true positive cases with malignant neuronal involvement, 4 false positive cases diagnosed clinically as radiotherapy-induced neuropathy, 34 true negative cases and 2 false negative cases with negative PET/CT study and clinical evidence of nerve affection with sensitivity 83.33%, specificity 89.47%, PPV 71.43%, NPV 94.44% and diagnostic accuracy 88%. P-value > 0.05 was considered statistically significant. Conclusion PET/CT has a significant role in detection of neuronal involvement by malignancy in cancer patients. Correlation between PET/CT and clinical outcome after chemotherapy improves the accuracy of diagnosis.

Objectives: The objective of this study was to predict the outcome of shock wave lithotripsy (SWL) on the basis of computed tomography (CT) morphodensitometry for ureteral and renal stones. We also assessed the possibility that Hounsfield unit (HU) values and the location of the stones could be used to predict the outcome of SWL. Material and methods: A prospective study was performed to measure stone size, location, composition, surface area, surface volume, stone burden, the skin-to-stone distance and the HU for solitary renal and ureteral stones by non-contrast CT studies (NCCT) from August 2013 to September 2015. Success of SWL was defined as: (1) being stone-free or (2) residual stone fragments < 4 mm by radiography/NCCT. Results: Of the 100 assessed patients, 68 patients (68%) were stone-free, 12 (12%) had residual stone fragments < 4 mm (clinically insignificant residual fragments) and 20 (20%) had residual stone fragments ≥ 4 mm/ancillary procedures. Multivariate analysis revealed that stone location and mean HU were significant predictors of SWL success. Receiver operating characteristic curves defined cut-off values for predicting treatment outcome. Treatment success rates were significantly higher for stones < 800 HU than with stones > 800 HU ( p = 0.160). Conclusion: Evaluation of stone HU values and stone location prior to SWL can predict treatment outcome and aid in the development of treatment strategies. Level of evidence 2 & 4

Background: F18-PET/CT technique has been permanently optimized to ensure the best accuracy and to extend its clinical application. Radiation protection remains an omnipresent aspect of daily practice in F18-PET/CT. Introduction: We tried to demonstrate the usefulness of remotely controlled radiopharmaceutical dispensers with smart-phones or tablets in the optimization of staff exposure. Material and methods: We performed a study to evaluate the exposure during loading and dispensing of radiopharmaceuticals working in two different ways: according to the user's manual of the automatic dispenser and, respectively, with an e-controlling application. We calculated the maximal radiation exposure and analyzed the differences related to the annual effective dose. Have been considered 40 loading and 353 dispensing procedures. During the loading, it has been manipulated a total activity of 9348.8 mCi (345905.6 MBq) FDG. A total activity of 2622.5 mCi (97032.5 MBq) FDG has been manipulated during dispensing. Results: The effective dose resulted from the loading procedure measured at the dispenser contact was 445.05 µSv. The effective dose measured in the remote control area during the loading procedure was 0.34 µSv, having a difference of 444.71 µSv. The total effective dose during dispensing procedures measured at the dispenser was 206.6 µSv and the total effective dose measured in the controlling room was 2.64 µSv, thus a difference of 203.96 µSv. The cumulative difference between the effective doses was of 648.67 µSv. Discussion: E-controlling the dispenser, we got an exposure saving representing 61.2% from the operator's annual dose. Conclusions: This study demonstrates the effectiveness of e-controlling devices in radiation protection of the staff working in F18-PET/CT.

Ga-DOTATATE imaging is commonly used for the detection of metastatic disease in neuroendocrine tumors. We present a case of a 69-year-old woman postsurgery for lung carcinoid tumor in which sequential follow-up Ga-DOTATATE PET/CT studies identified focal hepatic uptake that was presumed to represent a liver metastasis. However, correlative imaging with MRI revealed a focal fatty sparing of the liver composed of benign hepatic parenchyma at that area accompanied with diffuse liver steatosis in the background of the "pseudolesion." This report demonstrates a potential "false-positive" hepatic finding that can strikingly mimic a metastasis in neuroendocrine tumor imaging.

Introduction Colorectal cancer is the fourth leading cause of cancer mortality in developed countries. There is evidence supporting a disproportionate loss of skeletal muscle as an independent prognostic factor. The importance of the systemic inflammatory response as a unifying mechanism for specific loss of skeletal muscle mass in patients with cancer is increasingly recognized. The aim of the present study was to delineate the relationship between the systemic inflammatory response, skeletal muscle index (SMI), skeletal muscle density (SMD), and overall survival in patients with colorectal cancer. Materials and methods The study included 650 patients with primary operable colorectal cancer. Computed tomography scans were used to define the presence of visceral obesity, sarcopenia (low SMI), and myosteatosis (low SMD). Tumour and patient characteristics were recorded. Survival analysis was carried out using univariate and multivariate Cox regression. Results A total of 650 patients (354 men and 296 women) were included. The majority of patients were over 65 years of age (64%) and overweight or obese (68%). On univariate survival analysis, age, ASA, TNM stage, modified Glasgow Prognostic Score (mGPS), body mass index, subcutaneous fat index, visceral obesity, SMI, and SMD were significantly associated with overall survival (all P

Accurate prediction of multiscale fracture process of concrete relies on modeling of concrete mesostructures. Though high-resolution yet realistic mesostructures can be obtained by CT technique, the size limitation of reconstructed mesostructures is still an outstanding task. In this paper, a novel method of generating synthetic mesostructures of concrete based on generative adversarial networks is proposed. After training with CT images of a limited size, a large amount of mesostructures with arbitrary sizes are generated. Subsequently, a systematic scheme for investigating fracture process of concrete is established by incorporating the proposed method with cohesive zone model. The geometric features of generated mesostructures, including two-point correlation functions and aggregate size distributions, are compared with actual CT images to quantitatively verify performance of the proposed method. Simulated crack patterns and macroscale mechanical response of generated mesostructures demonstrate close agreements with those of actual mesostructures, thus validating that the proposed method is an accurate and effective tool in the study of multiscale fracture analysis of concrete.

According to the international societies’ recommendations, the 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT) technique should not be used as the method of choice in brain tumour diagnosis. Therefore, the brain region can be omitted during standard [18F]FDG PET/CT scanning. We performed comprehensive literature research and analysed results from 14,222 brain and torso [18F]FDG PET/CT studies collected in 2010–2020. We found 131 clinically silent primary and metastatic brain tumours and 24 benign lesions. We concluded that the brain and torso [18F]FDG PET/CT study provides valuable data that may support therapeutic management by detecting clinically silent primary and metastatic brain tumours.

Introduction The prevalence of incidental 18 F-fluorodeoxyglucose (FDG)-avid findings on positron emission tomography-computed tomography (PET/CT) has been extensively described. Few studies, however, have assessed the prevalence and significance of non-FDG-avid findings; pathology that is identified on review of the low-dose, non-contrast CT. The aim of this study was to determine the overall prevalence of non FDG-avid incidental findings on PET/CT and the prevalence of 'clinically significant' non FDG-avid pathology. Methods Five hundred consecutive whole body PET/CT studies performed in 2016 at a university affiliated tertiary hospital were retrospectively reviewed by two radiologists experienced in reporting PET/CT. Findings were categorized according to potential clinical relevance, and a targeted follow-up of clinically significant incidental findings was performed. Results Incidental findings were encountered in 463 of 500 (92.6%) patients. In 226 patients, these findings had been detected on previous imaging studies, with unknown incidental findings present in 237 of 500 (47.4%) patients. 113 of 500 (22.6%) patients had non-avid incidental findings of potentially major clinical significance, and in 35 patients (7.0%) these findings were considered previously unknown. The most common non-avid findings of potentially major significance were pulmonary nodules (6 mm or larger), moderate or large size pleural effusions, and vascular aneurysms. Unknown incidental findings of potentially major clinical significance were significantly higher in patients imaged for melanoma staging (P= 0.004). Conclusion The prevalence of incidental findings of clinical significance that do not accumulate FDG in PET/CT is not insignificant. Routine systematic review of the low-dose CT is required to avoid missing potentially clinically important findings, in particular pleural effusions, vascular aneurysms and metastatic pulmonary nodules.

Positional change in the retropharyngeal carotid artery, a rare phenomenon over time, is even rarer in previous reports, and it is important to be aware of this before any neck surgical procedure. A woman in her 50s underwent an anterior maxillectomy for upper gingival cancer, without neck dissection. The patient had medical histories of diabetes mellitus and liver dysfunction, with unremarkable family histories. Serial neck contrast-enhanced computed tomography for detecting locoregional recurrence had been performed as a follow-up during 4 years. A radiological course of moving carotid arteries in serial computed tomography studies showed reciprocating positional changes (wandering) between normal and retropharyngeal regions. There was no locoregional recurrence of the gingival cancer. This is the first case to describe a so-rare presentation of wandering carotid arteries. It is important for clinicians to be aware of a wandering carotid artery to avoid potentially fatal complications.

Objective: to develop a methodology for quantitative assessment of changes in density parameters of pulmonary tissue on the basis of dynamic CT data, which makes it possible to assess the presence of the dependence of changes in lung tissue on the time elapsed after radiation therapy (RT), the dose and volume of irradiated pulmonary tissue.Materials and methods. Using the data collected by 11 patients with malignant lymphomas, we developed a new diagnostic technique for quantitative analysis, which is based on the analysis of the density of pulmonary tissue before and after RT in areas with a selected range of doses throughout the lung volume. All selected patients received LT in the chest region, using 3D-planning, fractions of 2Gy and total focal doses of 13–56 Gy. Also, each patient had at least two CT examinations (a total of 25 studies in the Dicom- format). The first CT scan was performed before LT, repeated – within 2–7 months after the end of RT.Results. In 6 patients, control CT examinations were performed 2.1–2.8 months after RT. As a result, a quantitative increase in the density indices in the range from +12 to +62 HU in regions of the lungs irradiated at a dose of more than 19 Gy was noted, different from the control areas. The volume of these areas of the lungs was from 16% to 30% of the total lung volume, and the volume of regions with the maximum values of density growth – from 7% to 14%. These changes in density are below the “visual” threshold. In control areas, the density change varied from −15 HU (increased airiness) to + 8 HU. According to the data of other CT studies performed later than 3 months after RT, the reverse development of changes characterizing the early radiation reaction was observed.Conclusions. A series of CT studies performed before and at various intervals after RT allows quantitative assessment of the dynamics of the indices of the density of irradiated pulmonary tissue, which is necessary for an objective assessment of the severity of early radiation-induced injuries of pulmonary tissue sites, depending on the dose. A study of the dynamics of these changes in pulmonary tissue density over time with RT and the connection of this indicator with the baseline data may allow one to predict radiation-induced damage to the lungs on the one hand, and on the other, to evaluate individual radiosensitivity.

The main objective of this article was to analyze prevalence data about myocardial bridging (MB) in published studies. To this purpose, we performed a meta-analysis of studies published in English literature that contained data about the prevalence of MB and its anatomical characteristics. The overall prevalence was 19% (CI: 17-21%); autopsy studies revealed an overall prevalence of 42% (CI: 30-55%), CT studies 22% (CI: 18-25%), and coronary angiography 6% (CI: 5-8%). Most bridges were located on the left anterior descending artery (82% overall, 63% on autopsy studies), had a mean thickness of 2.47 mm and a mean length of 19.3 mm. In conclusion, autopsy studies should be the gold standard in evaluating the actual prevalence of myocardial bridges, while in vivo high-resolution CT scanning should be preferred to coronary angiography studies.

Objectives To benchmark CT-dose data for standard adult CT studies to regional and national reference levels using a dose-tracking system. Methods Data from five CT systems from three hospitals were collected over a 1- to 2.5-year period (2012–2014), using the same type of dose management system. Inclusion criteria were adult patients and standard CT-head, CT-abdomen-pelvis, CT-thorax, CT-lumbar spine, CT-pulmonary embolism, CT-cervical spine and CT-thorax-abdomen studies, with one helical scan. Volumetric CT-dose index (CTDIvol), dose length product (DLP) and scan length from 31,709 scans were analysed statistically. Results After dose optimisation CTDIvol and DLP values were below the national diagnostic reference levels (DRLs) for all CT studies and for all systems investigated. Mostly no significant differences were found between CTDIvol and DLP levels (p values ≥ 0.01) of CT studies performed on different scanners within the same hospital. Significant dose differences (p values < 0.01) were instead observed among hospitals for comparable CT studies. Dose level range and scan length differences for similar CT studies were revealed. Conclusions Dose-tracking systems help to reduce CT-dose levels below national DRLs. However, dose and protocol data comparison between and within hospitals has the potential to further reduce variability in dose data of standard adult CT studies. Key Points • Retrospective three-centre study on dose levels of standard adult CT procedures. • Dose-tracking systems help hospitals to stay below national dose reference levels. • Dose-tracking systems help to align CT dose levels between scanners within hospitals. • Benchmarking shows CT dose level variability for similar examinations in different hospitals. • Differences in dose level range/scan length for similar CT studies are revealed. Electronic supplementary material The online version of this article (10.1007/s13244-017-0570-5) contains supplementary material, which is available to authorized users.

Objective Fever of unknown origin (FUO) is a diagnostic challenge. This study aimed to assess the efficacy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) and gallium-67 single-photon emission computed tomography/computed tomography ( 67 Ga SPECT/CT) in diagnosing FUO. Methods A total of 68 patients with FUO underwent 18 F-FDG PET/CT and 67 Ga SPECT/CT from January 2013 through May 2016. Images were read independently. The imaging results were compared with the final diagnosis and categorized as helpful for diagnosis or non-contributory to diagnosis in the clinical setting. Associations between categorical variables were evaluated with the chi-square test or Fisher's exact test. Results Ten of the 68 patients were excluded. An infectious underlying disease was found in 23 patients. A malignant disorder was the cause of FUO in 10 patients. Non-infectious inflammatory disease was found in 11 patients. Adrenal insufficiency was the cause of FUO in two patients. The cause of FUO was not found for 12 patients. A high false-positive rate of 44% (7/16) was observed for 18 F-FDG PET/CT, while a high false-negative rate of 55% (23/42) was observed for 67 Ga SPECT/CT. 18 F-FDG PET/CT studies depicted all 67 Ga-avid lesions. The sensitivity (79% vs. 45%) and clinical contribution (72% vs. 55%) of 18 F-FDG PET/CT in diagnosing FUO were significantly higher than those of 67 Ga SPECT/CT ( p Conclusions On the basis of this study, the diagnostic performance of 18 F-FDG PET/CT is superior to 67 Ga SPECT/CT in the work-up of patients with FUO. With its rapid results and superior sensitivity, 18 F-FDG PET/CT may replace 67 Ga SPECT/CT where this technique is available.

OBJECTIVE To determine the vertebral heart size in chinchillas using right and left lateral radiographic views and CT images. To evaluate the agreement between radiographic and CT modalities. METHODS Twenty-one clinically healthy chinchillas and seven chinchillas with cardiovascular abnormalities underwent cardiovascular examination before thoracic radiographs and thoracic CT obtained under dexmedetomidine-ketamine anaesthesia. Two observers calculated vertebral heart size for radiographic and CT studies. Reference intervals were calculated with the robust method. Agreement between radiographic and CT-derived vertebral heart size was evaluated with Bland-Altman plots and Deming regression. RESULTS Mean ±sd vertebral heart size for lateral radiographs was 8·9 ±0·62 (reference interval: 7·5 to 10·2) and for CT-derived vertebral heart size was 8·2 ±0·55 (reference interval: 7·1 to 9·4). CT significantly underestimated the radiographic vertebral heart size by 0·66 vertebrae. There was no significant difference between vertebral heart size for right and left lateral radiographic views, or between female and male chinchillas. CLINICAL SIGNIFICANCE Radiographic vertebral heart size for chinchillas is larger than that reported for similar rodents. Vertebral heart size can be calculated using radiography or CT in chinchillas, but these techniques are not interchangeable.

Purpose To develop, in a phantom environment, a method to obtain multidetector computed tomographic (CT) data sets at multiple radiation exposure levels within the same patient and to validate its use for potential dose reduction by using different image reconstruction algorithms for the detection of liver metastases. Materials and Methods The American College of Radiology CT accreditation phantom was scanned by using a dual-source multidetector CT platform. By adjusting the radiation output of each tube, data sets at six radiation exposure levels (100%, 75%, 50%, 37.5%, 25%, and 12.5%) were reconstructed from two consecutive dual-source single-energy (DSSE) acquisitions, as well as a conventional single-source acquisition. A prospective, HIPAA-compliant, institutional review board-approved study was performed by using the same DSSE strategy in 19 patients who underwent multidetector CT of the liver for metastatic colorectal cancer. All images were reconstructed by using conventional weighted filtered back projection (FBP) and sinogram-affirmed iterative reconstruction with strength level of 3 (SAFIRE-3). Objective image quality metrics were compared in the phantom experiment by using multiple linear regression analysis. Generalized linear mixed-effects models were used to analyze image quality metrics and diagnostic performance for lesion detection by readers. Results The phantom experiment showed comparable image quality between DSSE and conventional single-source acquisition. In the patient study, the mean size-specific dose estimates for the six radiation exposure levels were 13.0, 9.8, 5.8, 4.4, 3.2, and 1.4 mGy. For each radiation exposure level, readers' perception of image quality and lesion conspicuity was consistently ranked superior with SAFIRE-3 when compared with FBP (P ≤ .05 for all comparisons). Reduction of up to 62.5% in radiation exposure by using SAFIRE-3 yielded similar reader rankings of image quality and lesion conspicuity when compared with routine-dose FBP. Conclusion A method was developed and validated to synthesize multidetector CT data sets at multiple radiation exposure levels within the same patient. This technique may provide a foundation for future clinical trials aimed at estimating potential radiation dose reduction by using iterative reconstructions.

Aim To evaluate the ability of SUVmax to differentiate bone metastases from degenerative lesions, blastic from lytic metastases, as well as to determine the correlation between SUVmax with 18 F-NaF and with 18 F-FDG. Material and methods A review was performed on 115 18 F-NaF PET/CT studies. Of the 64 patients with bone metastases, 49 (39 women, 10 men, 61 ± 12 years (16–81)), in whom the PET/CT supported the diagnosis of bone metastases, were selected for analysis. A record was made of the SUVmax of a maximum of ten metastases in each patient (total 172: 141 blastic, 31 lytic), as well as four degenerative lesions (total 188) with the greatest 18 F-NaF uptake intensity. Of the 49 patients analyzed, 43 also had a 18 F-FDG PET/CT performed in which a record was made of the SUVmax values for 18 F-FDG calculated in the locations corresponding to the bone metastases observed in the 18 F-NaF PET/CT: 128 metastases (106 blastic, 22 lytic). Results The mean of the SUVmax values was significantly higher in metastases than in degenerative lesions, 26.8 ± 17.3 vs . 15.3 ± 6.3 ( P vs . 22.1 ± 11.3 ( P = 0.03). A SUVmax value above 42 always represented metastases, with all values above 49 representing blastic metastases. Using the SUVmax values, it was possible to predict the occurrence of metastases (AUC = 0.723; P 18 F-NaF was significantly higher in blastic metastases (27.9 ± 18.3 vs . 22.1 ± 11.3, P = 0.03), whereas with 18 F-FDG it was significantly higher in lytic ones (3.9 ± 3.4 vs . 9.6 ± 3.3; P Conclusions SUVmax can contribute to the differentiation of metastases from degenerative lesions, and blastic from lytic metastases.

To determine if focal increased uptake at the rotator interval (RI) and/or inferior capsule (IC) on18F-FDG PET/CT (“positive PET”) predicts the presence of adhesive capsulitis (AC). Three populations were retrospectively examined. Group 1 included 1,137 consecutive 18F-FDG PET/CT studies and was used to determine the prevalence of focal uptake at the RI or IC. Group 2 included 361 cases from a 10-year period with 18F-FDG PET/CT and MRI of shoulder performed within 45 days of each other and was used to enrich the study group. Group 3 included 109 randomly selected patients from the same time frame as groups 1 and 2 and was used to generate the control group. The study group consisted of 15 cases from the three groups, which had positive PET findings. PET/CT images were assessed in consensus by two musculoskeletal radiologists. The reference standard for a diagnosis of AC was clinical and was made by review of the medical record by a pain medicine physician. The prevalence of focal activity at either the RI or IC (“positive PET”) was 0.53%. Nine patients had a clinical diagnosis of AC and 15 patients had a positive PET. The sensitivity and specificity of PET for detection of AC was 56% and 87%, respectively. PET/CT had a positive likelihood ratio for AC of 6.3 (95% CI: 2.8–14.6). Increased uptake at the RI or IC on PET/CT confers a moderate increase in the likelihood of AC.

ObjectiveA subset of patients with sinonasal disease who obtain a diagnostic computed tomography (CT) sinus scan may require repeat preoperative CT due to the inadequacy of diagnostic CT for image-guided sinus surgery (IGSS). This leads to increased CT utilization, health care costs, and patient exposure to ionizing radiation. The objective of this study is to determine the frequencies of diagnostic CT sinus studies that were inadequate for IGSS and repeat CT studies for purposes of IGSS.Study DesignA retrospective chart study was performed between May 2012 and August 2013.SettingTertiary care rhinology practice.Subjects and MethodsNew patients with any sinonasal diagnosis who presented with CT sinus scans acquired from outside institutions were included. CT scans were considered inadequate for IGSS for any of the following reasons: >1.5-mm slice thickness, oblique axial planes due to gantry tilt, and incompletely defined or missing IGSS anatomic landmarks.ResultsOf 183 patients, 85 (46%) presented with d...

Air embolism in trauma chest is threatening complication, often leading to a fatal outcome affected. In most cases, diagnosis is posthumous, after forensic autopsy. Based on the submitted clinical observation and analysis of the literature shows the fatality of this terrible complication of chest trauma. The role of CT studies on patients affected by the accident.