Radiologic mimics of pulmonary embolism.

The diagnosis of pulmonary embolism (PE) is often made more challenging by the presence of diseases that can mimic thromboembolic disease. There is no specific or sensitive constellation of clinical signs or symptoms that can be used to diagnose PE. Ventilation/perfusion scans can have false-positive findings related to mediastinal conditions that can compress the pulmonary arteries, and pulmonary hemorrhage can resemble PE on V/Q scanning with potentially devastating consequences if anticoagulation is started. CT-scan related issues l eading to potential false-positive diagnoses range from inadequate imaging technique, to systemic-pulmonary shunting, to non-thrombotic occlusion of pulmonary arteries by tumor, septic emboli, and emboli of fat, air, and foreign material, as well as vasculitic processes. Careful assessment of the patient and consideration of these potential mimickers is imperative to correct diagnosis of this potentially life-threatening condition.

Long-term medical imaging use in children with central nervous system tumors.

BACKGROUND: Children with central nervous system (CNS) tumors undergo frequent imaging for diagnosis and follow-up, but few studies have characterized longitudinal imaging patterns. We described medical imaging in children before and after malignant CNS tumor diagnosis. PROCEDURE: We conducted a retrospective cohort study of children aged 0-20 years diagnosed with CNS tumors between 1996-2016 at six U.S. integrated healthcare systems and Ontario, Canada. We collected computed topography (CT), magnetic resonance imaging (MRI), radiography, ultrasound, nuclear medicine examinations from 12 months before through 10 years after CNS diagnosis censoring six months before death or a subsequent cancer diagnosis, disenrollment from the health system, age 21 years, or December 31, 2016. We calculated imaging rates per child per month stratified by modality, country, diagnosis age, calendar year, time since diagnosis, and tumor grade. RESULTS: We observed 1,879 children with median four years follow-up post-diagnosis in the U.S. and seven years in Ontario, Canada. During the diagnosis period (±15 days of diagnosis), children averaged 1.10 CTs (95% confidence interval [CI] 1.09-1.13) and 2.14 MRIs (95%CI 2.12-2.16) in the U.S., and 1.67 CTs (95%CI 1.65-1.68) and 1.86 MRIs (95%CI 1.85-1.88) in Ontario. Within one year after diagnosis, 19% of children had ≥5 CTs and 45% had ≥5 MRIs. By nine years after diagnosis, children averaged one MRI and one radiograph per year with little use of other imaging modalities. CONCLUSIONS: MRI and CT are commonly used for CNS tumor diagnosis, whereas MRI is the primary modality used during surveillance of children with CNS tumors.

Decreased Medical Care During the COVID-19 Pandemic - A Comprehensive Analysis of Radiological Examinations.

OBJECTIVES: As a cross-section discipline within the hospital infrastructure, radiological departments might be able to provide important information regarding the impact of the COVID-19 pandemic on healthcare. The goal of this study was to quantify changes in medical care during the first wave of the pandemic using radiological examinations as a comprehensive surrogate marker and to determine potential future workload. METHODS: A retrospective analysis of all radiological examinations during the first wave of the pandemic was performed. The number of examinations was compared to time-matched control periods. Furthermore, an in-depth analysis of radiological examinations attributed to various medical specialties was conducted and postponed examinations were extrapolated to calculate additional workload in the near future. RESULTS: A total of 596,760 examinations were analyzed. Overall case volumes decreased by an average of 41 % during the shutdown compared to the control period. The most affected radiological modalities were sonography (-54 %), X-ray (-47 %) followed by MRI (-42 %). The most affected medical specialty was trauma and orthopedics (-60 % case volume) followed by general surgery (-49 %). Examination numbers increased during the post-shutdown period leading to a predicted additional workload of up to 22 %. CONCLUSION: This study shows a marked decrease in radiological examinations in total and among several core medical specialties, indicating a significant reduction in medical care during the first COVID-19 shutdown. KEY POINTS: · Number of radiological examinations decreased by 41 % during the first wave of the COVID-19 pandemic.. · Several core medical specialties were heavily affected with a reduction of case volumes up to 60 %.. · When extrapolating postponed examinations to the near future, the overall workload for radiological departments might increase up to 22 %.. CITATION FORMAT: · Fleckenstein FN, Maleitzke T, Böning G et al. Decreased Medical Care During the COVID-19 Pandemic - A Comprehensive Analysis of Radiological Examinations. Fortschr Röntgenstr 2021; 193: 937 - 946.

Deep Learning Application in Spinal Implant Identification.

STUDY DESIGN: Retrospective observational study. OBJECTIVE: To demonstrate the clinical usefulness of deep learning by identifying previous spinal implants through application of deep learning. SUMMARY OF BACKGROUND DATA: Deep learning has recently been actively applied to medical images. However, despite many attempts to apply deep learning to medical images, the application has rarely been successful. We aimed to demonstrate the effectiveness and usefulness of deep learning in the medical field. The goal of this study was to demonstrate the clinical usefulness of deep learning by identifying previous spinal implants through application of deep learning. METHODS: For deep learning algorithm development, radiographs were retrospectively obtained from clinical cases in which the patients had lumbar spine one-segment instrument surgery. A total of 2894 lumbar spine anteroposterior (AP: 1446 cases) and lateral (1448 cases) radiographs were collected. Labeling work was conducted for five different implants. We conducted experiments using three deep learning algorithms. The traditional deep neural network model built by coding the transfer learning algorithm, Google AutoML, and Apple Create ML. Recall (sensitivity) and precision (specificity) were measured after training. RESULTS: Overall, each model performed well in identifying each pedicle screw implant. In conventional transfer learning, AP radiography showed 97.0% precision and 96.7% recall. Lateral radiography showed 98.7% precision and 98.2% recall. In Google AutoML, AP radiography showed 91.4% precision and 87.4% recall; lateral radiography showed 97.9% precision and 98.4% recall. In Apple Create ML, AP radiography showed 76.0% precision and 73.0% recall; lateral radiography showed 89.0% precision and 87.0% recall. In all deep learning algorithms, precision and recall were higher in lateral than in AP radiography. CONCLUSION: The deep learning application is effective for spinal implant identification. This demonstrates that clinicians can use ML-based deep learning applications to improve clinical practice and patient care.Level of Evidence: 3.

Review of deep learning algorithms for the automatic detection of intracranial hemorrhages on computed tomography head imaging.

Artificial intelligence is a rapidly evolving field, with modern technological advances and the growth of electronic health data opening new possibilities in diagnostic radiology. In recent years, the performance of deep learning (DL) algorithms on various medical image tasks have continually improved. DL algorithms have been proposed as a tool to detect various forms of intracranial hemorrhage on non-contrast computed tomography (NCCT) of the head. In subtle, acute cases, the capacity for DL algorithm image interpretation support might improve the diagnostic yield of CT for detection of this time-critical condition, potentially expediting treatment where appropriate and improving patient outcomes. However, there are multiple challenges to DL algorithm implementation, such as the relative scarcity of labeled datasets, the difficulties in developing algorithms capable of volumetric medical image analysis, and the complex practicalities of deployment into clinical practice. This review examines the literature and the approaches taken in the development of DL algorithms for the detection of intracranial hemorrhage on NCCT head studies. Considerations in crafting such algorithms will be discussed, as well as challenges which must be overcome to ensure effective, dependable implementations as automated tools in a clinical setting.

Evolution of cerebellomedullary fissure opening: its effects on posterior fossa surgeries from the fourth ventricle to the brainstem.

Surgical approaches to the fourth ventricle and its surrounding brainstem regions have changed significantly in the previous 30 years, after the establishment of cerebellomedullary fissure (CMF) opening. With the development of CMF opening techniques, CMF opening surgeries have become widely used for the treatment of various pathologies and have contributed to the improvement of surgical results in posterior fossa surgeries. We here review the historical progress of CMF opening surgeries to help the future progression of neurosurgical treatments. The authors studied the available literature to clarify how CMF opening surgeries have developed and progressed, and how much the idea and development of CMF opening techniques have affected the advancement of posterior fossa surgeries. With the establishment of angiography, anatomical studies on CMF in the 1960s were performed mainly to clarify vascular anatomy on radiological images. After reporting the microsurgical anatomy of CMF in a cadaveric study in 1982, one of the authors (T.M.) first proposed the clinical usefulness of CMF opening in 1992. This new method enabled wide exposure of the fourth ventricle without causing vermian splitting syndrome, and it took the place of the standard approach instead of the conventional transvermian approach. Several authors reported their experiences using this method from the end of the twentieth century to the early twenty-first century, and the naming of the approach, "telovelar approach" by Mussi and Rhoton in 2000 contributed to the global spread of CMF opening surgeries. The approach has become widely applied not only for tumors but also for vascular and brainstem lesions, and has assisted in the development of their surgical treatments, and brought up the idea of various fissure dissection in the posterior fossa. Studies of microsurgical anatomy of the fourth ventricle, including the CMF, has led to new surgical approaches represented by the transCMF/telovelar approach. The CMF opening method caused a revolution in posterior fossa surgeries. The idea was developed based on the experience gained while dissecting the CMF (the roof of the fourth ventricle) in the laboratory. Anatomical studies using cadaveric specimens, particularly their dissection by surgeons themselves, together with a deep understanding of brain anatomy are essential for further advancements in neurosurgical treatments.

Evaluation of Benefit and Cost Utility of Immediate Postanesthesia Care Unit Radiographs to Predict Airway Compromise After Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective review. OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure that may be complicated by airway compromise postoperatively. This life-threatening complication may necessitate reintubation and reoperation. We evaluated the cost utility of conventional postoperative x-ray. SUMMARY OF BACKGROUND DATA: Studies have demonstrated minimal benefit in obtaining an x-ray on postoperative day 1, but there is some utility of postanesthesia care unit (PACU) x-rays for predicting the likelihood of reoperation. METHODS: We retrospectively reviewed the records of consecutive patients who underwent ACDF between September 2013 and February 2017. Patients were dichotomized into those who received PACU x-rays and those who did not (control group). Primary outcomes were reoperation, reintubation, mortality, and health care costs. RESULTS: Eight-hundred and fifteen patients were included in our analysis: 558 had PACU x-rays; 257 did not. In those who received PACU x-rays, mean age was 53.7 ±â€Š11.3 years, mean levels operated on were 2.0 ±â€Š0.79, and mean body mass index (BMI) was 30.3 ±â€Š6.9. In those who did not, mean age was 51.8 ±â€Š10.9 years, mean levels operated on were 1.48 ±â€Š0.65, and mean BMI was 29.9 ±â€Š6.3. Complications in the PACU x-ray group were reintubation-0.4%, reoperation-0.7%, and death-0.3% (due to prevertebral swelling causing airway compromise). Complications in the control group were reintubation-0.4%, reoperation-0.8%, and death-0. There were no differences between groups with respect to reoperation (P = 0.92), reintubation (P = 0.94), or mortality (P = 0.49). The mean per-patient cost was significantly higher (P = 0.009) in those who received PACU x-rays, $1031.76 ±â€Š948.67, versus those in the control group, $700.26 ±â€Š634.48. Mean length of stay was significantly longer in those who had PACU x-rays (P = 0.01). CONCLUSION: Although there were no differences in reoperation, reintubation, or mortality, there was a significantly higher cost for care and hospitalization in those who received PACU x-rays. Further studies are warranted to validate the results of the presented study.Level of Evidence: 3.

Preoperative and Postoperative Sitting Radiographs for Adult Spinal Deformity Surgery: Upper Instrumented Vertebra Selection Using Sitting C2 Plumb Line Distance to Prevent Proximal Junctional Kyphosis.

STUDY DESIGN: Case-control study from a continuous series. OBJECTIVES: To study the impact of perioperative sitting radiographs in adult spinal deformity (ASD) patients and determine whether proximal junctional kyphosis (PJK) can be prevented using preoperative sitting radiograph. SUMMARY OF BACKGROUND DATA: Radiographic analysis of ASD comprises standing whole-spine radiography which cannot evaluate the relaxed posture without head-to-foot compensation. METHODS: Preoperative and postoperative whole-spine standing and sitting radiographs and proximal mechanical complications in surgically treated spinal disorders with a minimum of 1-year follow-up were studied. Whole-spinal alignment was defined by cervical lordosis (CL), sagittal vertical axis (SVA), T1 slope (T1S), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and level of kyphotic apex (KA). Proximal mechanical complication was described as a PJK (proximal junctional angle >20°) or reoperation due to proximal junctional failure. RESULTS: Surgically treated 113 patients were prospectively investigated. Patients were divided into either the ASD (thoracic to ilium posterior corrective fusion), or non-ASD groups. In the ASD group, 10 patients had postoperative PJK, and three revision surgeries were carried out due to PJF with neurological deficit. Comparing standing with sitting positions, CL, TK, and PT became larger, SVA became frontal, LL and SS became smaller, and KA became caudal particularly in the ASD group. Logistic regression analysis demonstrated that the most influenced plumb line for PJK was the upper instrumented vertebra (UIV) to C2 plumb line distance, with a cutoff value of 115 mm for predicting PJK. CONCLUSION: Our findings highlight the usefulness of sitting spinal alignment evaluation, particularly in ASD patients, with maximum effort of thoracic spine and lower extremity compensation at standing. Mechanical complications such as PJK could be predicted using the distance from the planned UIV to the C2 plumb line in preoperative sitting radiographs. LEVEL OF EVIDENCE: 3.

Advanced X-ray Imaging Technology.

Since their discovery by Wilhelm Conrad Röntgen in 1895, X-rays have become the most widely available, typically fastest, and usually most cost-effective medical imaging modality today. From the early radiographic approaches using X-ray films as detectors, the portfolio of medical X-ray imaging devices developed into a large range of dedicated instrumentation for various applications. While X-ray imaging has come a long way, there are some physical properties of X-rays, which have not yet been fully exploited, and which may offer quite some room for further enhancements of current X-ray imaging equipment. Firstly, X-ray imaging today is mainly black and white, despite the fact that X-ray generators actually create a full spectrum of X-ray energies, and that the interactions of X-rays that occur within the human body are not the same for all energies and every material. Exploiting these spectral dependencies allows to not only obtain a black and white CT image, but also to obtain more molecularly specific information, which is relevant particularly in oncological precision radiology. The second aspect of X-rays, and so far in radiology mainly neglected and unused, is the physical fact that X-rays can also be interpreted in the wave picture, and not only as presently been done in the particle picture. If interpreted as waves, X-rays-just like visible light-experience a phase shift in matter, and this-if exploited correctly-can produce a new class of X-ray images, which then depict the wave interactions of X-rays with matter, rather than only the attenuating properties, as done until now.

Do Children With Spinal Deformity Who Have Metal Implants and Frequent Exposure to X-Rays Increase Their Risk of Cancer?

STUDY DESIGN: Spinal surgery cohort. OBJECTIVE: The authors assess the risk of cancer in children who have undergone frequent radiographs and have metal implants for the treatment of spinal deformity. SUMMARY OF BACKGROUND DATA: Concerns have been raised regarding the cancer risk to children exposed to repeated radiological examinations as part of routine surveillance to monitor progression of spinal deformity. Additionally, there are reports of increased cancer risk in adults having joint replacement with metal implants causing raised metal ion levels in the blood. METHODS: A large number of consecutive children undergoing instrumented spinal surgery since 1979 were examined for their development of malignancy. High quality data on all invasive cancers from the South Australian Cancer Registry and deaths were linked to the spinal surgery cohort with the calculation of standardized incidence ratios (SIRs) using the Quinquinquennium method. RESULTS: The study cohort was formed by 865 children. The average follow-up time from date of surgery to either death or censoring date was 18 years with a maximum of 36 years. A total of 15,921 person years were examined. There was no increased rate of cancer in these patients. For the total cohort, the SIR was 1.00 (95% confidence interval [CI] 0.50-1.79). For females the SIR was 0.83 (95% CI 0.33-1.70) and for males the SIR was 1.33 (95% CI 0.36-3.40). The male SIR reflected an expected cancer incidence of three cases, when four cases were observed, and was not statistically significant. CONCLUSION: This study has found that radiation exposure and possible exposure to circulating metal ions as a result of routine instrumented spine surgery in children since 1979 is not associated with an increased risk of cancer in up to 36 years of follow up. LEVEL OF EVIDENCE: 2.

Myths and facts about artificial intelligence: why machine- and deep-learning will not replace interventional radiologists.

Artificial intelligence (AI) is revolutionizing healthcare and transforming the clinical practice of physicians across the world. Radiology has a strong affinity for machine learning and is at the forefront of the paradigm shift, as machines compete with humans for cognitive abilities. AI is a computer science simulation of the human mind that utilizes algorithms based on collective human knowledge and the best available evidence to process various forms of inputs and deliver desired outcomes, such as clinical diagnoses and optimal treatment options. Despite the overwhelmingly positive uptake of the technology, warnings have been published about the potential dangers of AI. Concerns have been expressed reflecting opinions that future medicine based on AI will render radiologists irrelevant. Thus, how much of this is based on reality? To answer these questions, it is important to examine the facts, clarify where AI really stands and why many of these speculations are untrue. We aim to debunk the 6 top myths regarding AI in the future of radiologists.

Missed posterior shoulder fracture dislocations: a new protocol from a London major trauma centre.

BACKGROUND: A high incidence of missed posterior shoulder dislocations is widely recognised in the literature. Concern was raised by the upper limb multidisciplinary team at a London major trauma centre that these missed injuries were causing serious consequences due to the need for surgical intervention and poor functional outcome. OBJECTIVE: To identify factors contributing to missed diagnosis and propose solutions. METHODS: A local quality improvement report was performed investigating time from admission to diagnosis of simple posterior dislocations and fracture dislocations over a 5-year period. Factors contributing to a delayed diagnosis were analysed. RESULTS: The findings supported current evidence: a posterior shoulder dislocation was more often missed if there was concurrent fracture of the proximal humerus. Anteroposterior and scapular Y view radiographs were not always diagnostic for dislocation. Axial views were more reliable in assessment of the congruency of the joint and were associated with early diagnosis and appropriate treatment of the injury. DISCUSSION: As a result of these findings a new protocol was produced by the orthopaedic and radiology departments and distributed to our emergency department practitioners and radiography team. The protocol included routine axial or modified trauma axial view radiographs for all patients attending the emergency department with a shoulder injury, low clinical suspicion for dislocation and a low threshold for CT scan. Reaudit and ongoing data collection have shown significant increase in axial view radiographs and improved diagnosis.

European trends in radiology: investigating factors affecting the number of examinations and the effective dose.

The advances in technology have led to a growing trend in population exposure to radiation emerging from the invention of high-dose procedures. It is, for example, estimated that annually 1.2% of cancers are induced by radiological scans in Norway. This study aims to investigate and discuss the frequency and dose trends of radiological examinations in Europe. European Commission (EC) launched projects to gain information for medical exposures in 2004 and 2011. In this study, the European Commission Radiation Protection (RP) reports No. 154 and 180 have been reviewed. The RP 154 countries' data were extracted from both reports, and the average variation trend of the number of examinations and effective doses were studied. According to the results, plain radiography and fluoroscopy witnessed a reduction in the frequency and effective dose per examination. Nevertheless, European collective dose encountered an average increase of 23%, which resulted from a growing tendency for implementation of high-dose procedures such as CT scans and interventional examinations. It is worth noting that most of the CT procedures have undergone an increase in effective dose per examination. Although demand and dose per examination in some radiological procedures (such as intravenous urography (IVU) have been reduced, population collective dose is still rising due to the increasing demand for CT scan procedures. Even though the individual risks are not considerable, it can, in a large scale, threaten the health of the people at the present time. Due to this fact, better justification should be addressed so as to reduce population exposure.

Trunk Growth in Early-Onset Idiopathic Scoliosis Measured With Biplanar Radiography.

STUDY DESIGN: Cross-sectional and longitudinal retrospective study. OBJECTIVES: To measure thoracic dimensions and volume during growth in early-onset idiopathic scoliosis (EOIS) patients and to compare them to a population of asymptomatic adults and to the previous literature. SUMMARY OF BACKGROUND DATA: Data on trunk growth for scoliotic children between 6 and 14 years of age is sparse in the literature. METHODS: Thirty-six patients (29 girls and 7 boys, between 3 and 14 years old, average Cobb angle 33°±15°) were included, all with a minimum two-year follow-up. Sixty-one asymptomatic girls and 54 asymptomatic adults were included as control groups. All subjects underwent biplanar radiography and 3D reconstruction of the spine, pelvis, and rib cage. EOIS patients repeated their radiologic examination every six months. Cobb angle, rib cage volume, anteroposterior and transverse diameters, thoracic index, thoracic perimeter, pelvic incidence, and T1-T12 and T1-S1 distance were calculated. Reproducibility of measurement was assessed. RESULTS: Measurement reliability in such young patients was comparable to previous studies in adolescents and adults. Geometrical parameters of EOIS patients increased linearly with age. For instance, rib cage volume in girls with EOIS increased from 2200 cm3 at six to seven years of age to 4100 cm3 at 13-14 years (65% of adult values, 294 cm3/y). Comparison with asymptomatic girls showed that EOIS could affect growth spurt. Longitudinal analysis on a cohort of six girls who had a follow-up of six years confirmed the cross-sectional data. CONCLUSIONS: In this longitudinal and cross-sectional study, trunk growth between 3 and 14 years of age was characterized, for the first time, with biplanar radiography and 3D reconstruction. The results can be useful to estimate patient growth and thus have potential application in the surgical planning of EOIS patients. LEVEL OF EVIDENCE: Level II, retrospective study.

Surgical Treatment of Lenke Type 5 Adolescent Idiopathic Scoliosis: A Systematic Review.

STUDY DESIGN: A systematic review. OBJECTIVE: To systemically review the previous literature regarding surgical treatment of Lenke type 5 adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The Lenke classification was published in 2001 as the classification of AIS. Since then, numerous articles have been published reporting the outcomes of surgical treatment of Lenke type 5 AIS. METHODS: The electronic databases PubMed, EMBASE, and Web of Science were queried up to Aug 2018 for articles regarding surgical treatment of Lenke type 5 AIS. Surgical variables, radiographic assessments, and clinical outcomes of surgical treatment of Lenke type 5 AIS were summarized. RESULTS: Fifty studies met the inclusion criteria. The average fused levels, % correction of thoracolumbar/lumbar curve at final follow-up, and % correction of thoracic curve at final follow-up for anterior and posterior procedures were reported to be 3.6-5.3 and 4.3-7.8 levels, 53-86 and 55-94% and 17-52 and 19-67%, respectively. Average coronal balance was imbalanced (≥20 mm) at preoperation in 22/43 reporting study groups and balanced (<20 mm) at final follow-up in all 37 reporting study groups. Scoliosis Research Society Version 22 scores showed no difference between anterior and posterior procedures in most of the reporting studies (5/6). CONCLUSION: Overall, the outcomes of surgical treatment of Lenke type 5 AIS are excellent. The thoracic curve was spontaneously corrected after surgery and coronal balance after surgery was better than before surgery. Both anterior and posterior procedures demonstrated satisfactory outcomes. LEVEL OF EVIDENCE: 4.

[From Xrays to PET/MR, and then? - Future imaging in pediatric radiology]. / Vom Röntgen zum PET/MRT, und dann? ­ Zukunftsweisende Bildgebung in der Kinderradiologie.

Significant changes can be expected in modern pediatric radiology. New imaging techniques are progressively added to basic modalities like Xrays and ultrasound. This essay summarizes recent advances and technical innovations in pediatric radiology, which are supposed to gain further importance in the future. Thus, CT dose reduction techniques including artificial intelligence as well as advances in the fields of magnetic resonance and molecular imaging are presented. KEY POINTS: · Technical innovations will lead to significant changes in pediatric radiology.. · CT dose reduction is crucial for pediatric patient collectives.. · New MR-techniques will lower the need for sedation and contrast media application.. · Functional MR-imaging might gain further importance in patients with chronic lung disease.. · Molecular imaging enables detection, characterization and quantification of molecular processes in tumors.. CITATION FORMAT: · Staatz G, Daldrup-Link HE, Herrmann J et al. From Xrays to PET/MR, and then? - Future imaging in pediatric radiology. Fortschr Röntgenstr 2019; 191: 357 - 366.

The Applications of Radiomics in Precision Diagnosis and Treatment of Oncology: Opportunities and Challenges.

Medical imaging can assess the tumor and its environment in their entirety, which makes it suitable for monitoring the temporal and spatial characteristics of the tumor. Progress in computational methods, especially in artificial intelligence for medical image process and analysis, has converted these images into quantitative and minable data associated with clinical events in oncology management. This concept was first described as radiomics in 2012. Since then, computer scientists, radiologists, and oncologists have gravitated towards this new tool and exploited advanced methodologies to mine the information behind medical images. On the basis of a great quantity of radiographic images and novel computational technologies, researchers developed and validated radiomic models that may improve the accuracy of diagnoses and therapy response assessments. Here, we review the recent methodological developments in radiomics, including data acquisition, tumor segmentation, feature extraction, and modelling, as well as the rapidly developing deep learning technology. Moreover, we outline the main applications of radiomics in diagnosis, treatment planning and evaluations in the field of oncology with the aim of developing quantitative and personalized medicine. Finally, we discuss the challenges in the field of radiomics and the scope and clinical applicability of these methods.

Review of 2-D/3-D Reconstruction Using Statistical Shape and Intensity Models and X-Ray Image Synthesis: Toward a Unified Framework.

Patient-specific three-dimensional (3-D) bone models are useful for a number of clinical applications such as surgery planning, postoperative evaluation, as well as implant and prosthesis design. Two-dimensional-to-3-D (2-D/3-D) reconstruction, also known as model-to-modality or atlas-based 2-D/3-D registration, provides a means of obtaining a 3-D model of a patient's bones from their 2-D radiographs when 3-D imaging modalities are not available. The preferred approach for estimating both shape and density information (that would be present in a patient's computed tomography data) for 2-D/3-D reconstruction makes use of digitally reconstructed radiographs and deformable models in an iterative, non-rigid, intensity-based approach. Based on a large number of state-of-the-art 2-D/3-D bone reconstruction methods, a unified mathematical formulation of the problem is proposed in a common conceptual framework, using unambiguous terminology. In addition, shortcomings, recent adaptations, and persisting challenges are discussed along with insights for future research.

Optical and x-ray technology synergies enabling diagnostic and therapeutic applications in medicine.

X-ray and optical technologies are the two central pillars for human imaging and therapy. The strengths of x-rays are deep tissue penetration, effective cytotoxicity, and the ability to image with robust projection and computed-tomography methods. The major limitations of x-ray use are the lack of molecular specificity and the carcinogenic risk. In comparison, optical interactions with tissue are strongly scatter dominated, leading to limited tissue penetration, making imaging and therapy largely restricted to superficial or endoscopically directed tissues. However, optical photon energies are comparable with molecular energy levels, thereby providing the strength of intrinsic molecular specificity. Additionally, optical technologies are highly advanced and diversified, being ubiquitously used throughout medicine as the single largest technology sector. Both have dominant spatial localization value, achieved with optical surface scanning or x-ray internal visualization, where one often is used with the other. Therapeutic delivery can also be enhanced by their synergy, where radio-optical and optical-radio interactions can inform about dose or amplify the clinical therapeutic value. An emerging trend is the integration of nanoparticles to serve as molecular intermediates or energy transducers for imaging and therapy, requiring careful design for the interaction either by scintillation or Cherenkov light, and the nanoscale design is impacted by the choices of optical interaction mechanism. The enhancement of optical molecular sensing or sensitization of tissue using x-rays as the energy source is an important emerging field combining x-ray tissue penetration in radiation oncology with the molecular specificity and packaging of optical probes or molecular localization. The ways in which x-rays can enable optical procedures, or optics can enable x-ray procedures, provide a range of new opportunities in both diagnostic and therapeutic medicine. Taken together, these two technologies form the basis for the vast majority of diagnostics and therapeutics in use in clinical medicine.