April 2021
Female Lower Urinary Tract Symptom Prevention and Treatment Strategies on Social Media: Mixed Correlation With Evidence.OBJECTIVE: To evaluate the level of evidence behind recommendations on social media for disease prevention in five lower urinary tract symptoms. MATERIALS & METHODS: We conducted a digital analysis of anonymous online posts on social media sites collected by a social media data mining service. One thousand posts about pelvic organ prolapse, stress urinary incontinence, overactive bladder, urinary tract infection, and interstitial cystitis/bladder pain syndrome were randomly selected. We analyzed these posts for recommendations regarding the prevention and treatment of these diseases, which were then compared to recommendations in available clinical guidelines and assessed for level of evidence.
April 2021
Minimizing Echo and Repetition Times in Magnetic Resonance Imaging Using a Double Half-echo k-space Acquisition and Low-rank Reconstruction.Sampling k-space asymmetrically (ie, partial Fourier sampling) in the readout direction is a common way to reduce the echo time (TE) during magnetic resonance image acquisitions. This technique requires overlap around the center of k-space to provide a calibration region for reconstruction, which limits the minimum fractional echo to ∿60% before artifacts are observed. The present study describes a method for reconstructing images from exact half echoes using two separate acquisitions with reversed readout polarity, effectively providing a full line of k-space without additional data around central k-space. This approach can benefit sequences or applications that prioritize short TE, short inter-echo spacing or short repetition time. An example of the latter is demonstrated to reduce banding artifacts in balanced steady-state free precession.
April 2021
Gut Wrenching: Cases of Missed Gastrointestinal Tumors and Their Mimics on Computed Tomography.Computed tomography (CT) of the abdomen and pelvis is one of the most common imaging studies ordered through the emergency department (ED). Because these studies are ordered for the detection of acute abnormalities and due to the relatively low incidence in patients presenting through the ED, gastrointestinal tumors are commonly missed. Moreover, many CT findings of malignant tumors overlap with benign entities, which can present a diagnostic challenge. This review article will describe the common CT findings of gastric, small bowel, colon, and appendiceal cancer as well as some of the common benign gastrointestinal conditions with similar imaging findings.
April 2021
The Emerging Role of Quantification of Imaging for Assessing the Severity and Disease Activity of Emphysema, Airway Disease, and Interstitial Lung Disease.There has been an explosion of use for quantitative image analysis in the setting of lung disease due to advances in acquisition protocols and postprocessing technology, including machine and deep learning. Despite the plethora of published papers, it is important to understand which approach has clinical validation and can be used in clinical practice. This paper provides an introduction to quantitative image analysis techniques being used in the investigation of lung disease and focusses on the techniques that have a reasonable clinical validation for being used in clinical trials and patient care.
April 2021
Guidelines for the Evaluation of Pulmonary Nodules Detected Incidentally or by Screening: A Survey of Radiologist Awareness, Agreement, and Adherence From the Watch the Spot Trial.PURPOSE: The aim of this study was to examine radiologists' beliefs about existing guidelines for pulmonary nodule evaluation. METHODS: A self-administered survey was developed to ascertain awareness of, agreement with, and adherence to published guidelines, including those from the Fleischner Society and the Lung CT Screening Reporting and Data System (Lung-RADS™). Surveys were distributed to 514 radiologists at 13 health care systems that are participating in a large, pragmatic trial of pulmonary nodule evaluation. Prespecified comparisons were made among groups defined by type of health system, years of experience, reader volume, and study arm.
April 2021
Percutaneous Intrauterine Device Placement: A Solution for Hematometra Due to Cervicovaginal Agenesis.Möllerian duct underdevelopment results in agenesis and atresia of the vagina,cervix, or uterus, which can lead to hematometra and hematometrocolpos.Management includes vaginal-cervical serial dilation and/or surgery andmenstrual suppression with endovaginallevonorgestrel intrauterine device(IUD) placement. However, these options are not feasible in vaginal agenesisbecause there is no external tract. This report describes the percutaneousplacement of an IUD to treat hematometra due to cervicovaginal agenesis.
April 2021
Trans-Synaptic Degeneration of the Optic Radiation from Optic Nerve Atrophy.Fourty-seven-year-old woman with 5-year history of progressive decreased left eye vision. Optical coherence tomography showed optic nerve atrophy (left > right) and brain MRI revealed T2 hyperintense signal along the course of left optic radiations. We present a case of a trans-synaptic degeneration of the optic radiation in a patient with confirmed optic atrophy. Trans-synaptic degeneration of the optic radiation without associated infarct or inflammatory disease has not been reported before in patients with optic atrophy.
April 2021
Endovascular Removal of Thrombus and Right Heart Masses Using the AngioVac System: Results of 234 Patients from the Prospective, Multicenter Registry of AngioVac Procedures in Detail (RAPID).PURPOSE: To assess device and procedural safety and technical success associated with the use of the AngioVac System to remove vascular thrombi and cardiac masses. MATERIALS & METHODS: The Registry of AngioVac Procedures in Detail (RAPID) study prospectively collected data for 234 patients receiving treatment with AngioVac at 21 sites between March 2016 and August 2019: 84 (35.9%) with caval thromboemboli (CTEs), 113 (48.3%) with right heart masses (RHMs), 20 (8.5%) with catheter-related thrombi (CRTs), and 4 (1.7%) with pulmonary emboli (PEs). Thirteen patients had a combination of procedures during the same admission.
April 2021
Role of Intravenous Tissue Plasminogen Activator in Acute Ischemic Stroke with Large Vessel Occlusion.OBJECTIVE: The goal of the present study was to determine the safety and efficacy of intravenous tissue plasminogen activator (IVT) in patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) undergoing mechanical thrombectomy (MT). METHODS: We performed a retrospective analysis of prospectively collected data gathered during a 3-year period for all our patients with AIS and LVO. We analyzed the stroke outcomes and complications between patients who had received a combination of IVT and MT and those who had undergone MT only. Standardized selection criteria, including the uniform use of perfusion imaging, were used for selection for MT, irrespective of IVT administration.
March 2021
Denosumab Treatment for Giant Cell Tumor of the Spine Including the Sacrum.STUDY DESIGN: This was a subanalysis of an international, multicenter, open-label study. OBJECTIVE: The aim of this study was to assess the efficacy and safety of denosumab in a subset of patients with giant cell tumors of bone (GCTB) of the spine including the sacrum from an international, open-label, single-arm, phase 2 study (ClinicalTrials.gov: NCT00680992). SUMMARY OF BACKGROUND DATA: Standard GCTB treatment is surgical removal, either by curettage or resection, combined with intraoperative adjuvant therapy; however, some sites may not be amenable to resection (e.g., skull, spine). METHODS: Adults or skeletally mature adolescents with pathologically confirmed GCTB of the spine including the sacrum, and radiologically measurable evidence of active disease, were included. Patients received denosumab (120 mg subcutaneously) once every 4 weeks during the treatment phase, with loading doses on days 8 and 15 of the first cycle. Patients had surgically unsalvageable GCTB (Cohort 1), had planned surgery expected to result in severe morbidity (Cohort 2), or were enrolled from a previous GCTB study (Cohort 3).
March 2021
Unique Challenges for Glioblastoma Immunotherapy-discussions Across Neuro-Oncology and Non-neuro-oncology Experts in Cancer Immunology. Meeting Report from the 2019 SNO Immuno-Oncology Think Tank.Cancer immunotherapy has made remarkable advances with over 50 separate Food and Drug Administration (FDA) approvals as first- or second-line indications since 2015. These include immune checkpoint blocking antibodies, chimeric antigen receptor-transduced T cells, and bispecific T-cell-engaging antibodies. While multiple cancer types now benefit from these immunotherapies, notable exceptions thus far include brain tumors, such as glioblastoma. As such, it seems critical to gain a better understanding of unique mechanistic challenges underlying the resistance of malignant gliomas to immunotherapy, as well as to acquire insights into the development of future strategies. An Immuno-Oncology Think Tank Meeting was held during the 2019 Annual Society for Neuro-Oncology Scientific Conference. Discussants in the fields of neuro-oncology, neurosurgery, neuro-imaging, medical oncology, and cancer immunology participated in the meeting. Sessions focused on topics such as the tumor microenvironment, myeloid cells, T-cell dysfunction, cellular engineering, and translational aspects that are critical and unique challenges inherent with primary brain tumors. In this review, we summarize the discussions and the key messages from the meeting, which may potentially serve as a basis for advancing the field of immune neuro-oncology in a collaborative manner.
March 2021
Society of Interventional Radiology Quality Improvement Standards for Percutaneous Transcatheter Embolization.Percutaneous embolization procedures are commonly performed by interventional radiologists. This quality improvement (QI) standard was first published in 2010 (1), and this document represents the second update. Since the 2010 standards, many additional randomized controlled trials, meta-analyses, and observational studies have been published on transcatheter embolization for various disease entities, further establishing embolization as an effective treatment. Additionally, the indications of embolization have expanded with newer procedures, like prostatic embolization for benign prostatic hyperplasia (BPH), and emerging procedures, such as left gastric artery embolization for the treatment of obesity and genicular artery embolization for the treatment of pain related to osteoarthritis (OA). This revised document includes a discussion on the performance of embolization procedures in pediatric patients, emphasizes the current literature, and builds upon previous documents to provide up-to-date information to ensure effective, safe, and high-quality care.
March 2021
Cryoablation for Palliation of Painful Bone Metastases: The MOTION Multicenter Study.PURPOSE: To assess the clinical effectiveness of cryoablation for palliation of painful bone metastases. MATERIALS & METHODS: MOTION (Multicenter Study of Cryoablation for Palliation of Painful Bone Metastases) (ClinicalTrials.gov NCT02511678) was a multicenter, prospective, single-arm study of adults with metastatic bone disease who were not candidates for or had not benefited from standard therapy, that took place from February 2016 to March 2018. At baseline, participants rated their pain using the Brief Pain Inventory-Short Form (reference range from 0 to 10 points); those with moderate to severe pain, who had at least one metastatic candidate tumor for ablation, were included. The primary effectiveness endpoint was change in pain score from baseline to week 8. Participants were followed for 24 weeks after treatment. Statistical analyses included descriptive statistics and logistic regression to evaluate changes in pain score over the postprocedure follow-up period.
March 2021
Prospect of Artificial Intelligence for the Assessment of Cardiac Function and Treatment of Cardiovascular Disease.During the past decade, artificial intelligence (AI) has become sufficiently advanced to begin impacting many aspects of the human life. Applications of AI in medicine have currently been limited to the gears that facilitate physicians' tasks and improve their clinical workflow. In cardiovascular medicine, AI has been integrated into software that facilitate data analysis used in research and development, diagnostic imaging and population health.
March 2021
Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Cancer.PURPOSE: Magnetic resonance imaging-guided transurethral ultrasound ablation uses directional thermal ultrasound under magnetic resonance imaging thermometry feedback control for prostatic ablation. We report 12-month outcomes from a prospective multicenter trial (TACT). MATERIALS AND METHODS: A total of 115 men with favorable to intermediate risk prostate cancer across 13 centers were treated with whole gland ablation sparing the urethra and apical sphincter. The co-primary 12-month endpoints were safety and efficacy.
March 2021
Image-Guided Biopsies and Interventions of Mediastinal Lesions.Optimal assessment of the mediastinal masses is performed by a combination of clinical, radiological and often histological assessments. Image-guided transthoracic biopsy of mediastinal lesions is a minimally invasive and reliable procedure to obtain tissue samples, establish a diagnosis and provide a treatment plan. Biopsy can be performed under Computed Tomography, MRI, or ultrasound guidance, using a fine needle aspiration or a core-needle. In this paper, we review the image-guided strategies and techniques for histologic sampling of mediastinal lesions, along with the related clinical scenarios and possible procedural complications. In addition, image-guided mediastinal drainage and mediastinal ablations will be briefly discussed.
March 2021
The Role of PSMA PET/CT and PET/MRI in the Initial Staging of Prostate Cancer.CONTEXT: Prostate cancer (PCa) is the most common solid organ malignancy in men and is the third leading cause of cancer death. Accurate methods for the detection and staging of PCa are necessary to determine the extent of disease and inform treatment options. OBJECTIVE: To review the performance and diagnostic accuracy of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging in the initial staging of PCa and evaluate its impact on definitive therapy planning. EVIDENCE ACQUISITION: A comprehensive literature search was performed using PubMed. References from retrieved articles and recommendations from the authors were also included.
March 2021
Rapid Measurement of the Low Contrast Detectability of CT Scanners.PURPOSE: Low contrast detectability (LCD) is a metric of fundamental importance in computed tomography (CT) imaging. In spite of this, its measurement is challenging in the context of nonlinear data processing. We introduce a new framework for objectively characterizing LCD with a single scan of a special-purpose phantom and automated analysis software. The output of the analysis software is a "machine LCD" metric which is more representative of LCD than contrast-noise ratio (CNR). It is not intended to replace human observer or model observer studies. METHODS: Following preliminary simulations, we fabricated a phantom containing hundreds of low-contrast beads. These beads are acrylic spheres (1.6 mm, net contrast ~10 HU) suspended and randomly dispersed in a background matrix of nylon pellets and isoattenuating saline. The task was to search for and localize the beads. A modified matched filter was used to automatically scan the reconstruction and select candidate bead localizations of varying confidence. These were compared to bead locations as determined from a high-dose reference scan to produce free-response ROC curves. We compared iterative reconstruction (IR) and filtered backpropagation (FBP) at multiple dose levels between 40 and 240 mAs. The scans at 60, 120, and 180 mAs were performed three times each to estimate uncertainty.
March 2021
Birt-Hogg-Dubé Syndrome Presenting with Chronic Progressive Dyspnea.Birt-Hogg-Dubé Syndrome (BHDS) is a rare autosomal dominant disease which manifests with cutaneous hamartomas, lung cysts and renal carcinomas. A wide spectrum of phenotypic expression and few visible manifestations makes BHDS a likely under-recognized entity. Diffuse cystic lung disease (DCLD) is the typical pulmonary manifestation of BHDS, which in the absence of other specific findings carries a broad differential diagnosis. Unlike many other causes of DCLD, BHDS is not known to present with symptomatic pulmonary dysfunction. We report a typical case of BHDS with an atypical presentation - chronic progressive dyspnea. The unusual presentation provides an opportunity to discuss the differential for DCLD and highlights the importance of maintaining an index of suspicion for BHDS even when symptoms appear inconsistent with the diagnosis. Also examined is the management of BHDS patients and their immediate relatives, and recommendations for the treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) given the potential risk of pneumothorax in this group.
March 2021
A Framework for Sharing Radiation Dose Distribution Maps in the Electronic Medical Record for Improving Multidisciplinary Patient Management.Radiation oncology practices use a suite of dedicated software and hardware that are not common to other medical subspecialties, making radiation treatment history inaccessible to colleagues. A radiation dose distribution map is generated for each patient internally that allows for visualization of the dose given to each anatomic structure volumetrically; however, this crucial information is not shared systematically to multidisciplinary medical, surgery, and radiology colleagues. A framework was developed in which dose distribution volumes are uploaded onto the medical center's picture archiving and communication system (PACS) to rapidly retrieve and review exactly where, when, and to what dose a lesion or structure was treated. The ability to easily visualize radiation therapy information allows radiology clinics to incorporate radiation dose into image interpretation without direct access to radiation oncology planning software and data. Tumor board discussions are simplified by incorporating radiation therapy information collectively in real time, and daily onboard imaging can also be uploaded while a patient is still undergoing radiation therapy. Placing dose distribution information into PACS facilitates central access into the electronic medical record and provides a succinct visual summary of a patient's radiation history for all medical providers. More broadly, the radiation dose map provides greater visibility and facilitates incorporation of a patient's radiation history to improve oncologic decision making and patient outcomes.
March 2021
68Ga-FAPi-46 Diffuse Bilateral Breast Uptake in a Patient with Cervical Cancer After Hormonal Stimulation.A 36-year-old female patient diagnosed with invasive squamous cell carcinoma of the cervix underwent an 18F-fluorodeoxyglucose ([18F]FDG) PET/CT scan for presurgical staging.
March 2021
Voxelwise and Patientwise Correlation of 18F-FDOPA PET, Relative Cerebral Blood Volume, and Apparent Diffusion Coefficient in Treatment-Naïve Diffuse Gliomas with Different Molecular Subtypes.Our purpose was to identify correlations between 18F-fluorodihydroxyphenylalanine (18F-FDOPA) uptake and physiologic MRI, including relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC), in gliomas with different molecular subtypes and to evaluate their prognostic values. METHODS: Sixty-eight treatment-naïve glioma patients who underwent 18F-FDOPA PET and physiologic MRI were retrospectively selected (36 with isocitrate dehydrogenase wild-type [IDHwt], 16 with mutant 1p/19q noncodeleted [IDHm-noncodel], and 16 with mutant codeleted [IDHm-codel]). Fluid-attenuated inversion recovery hyperintense areas were segmented and used as regions of interest. For voxelwise and patientwise analyses, Pearson correlation coefficients (r voxelwise and r patientwise) between the normalized SUV (nSUV), rCBV, and ADC were evaluated. Cox regression analysis was performed to investigate the associations between overall survival and r voxelwise, maximum or median nSUV, median rCBV, or median ADC.
February 2021
Case 286: Sarcoidlike Granulomatosis and Lymphadenopathy-Thoracic Manifestations of Nivolumab Drug Toxicity.History A 70-year-old man had a posterior left thigh lesion confirmed to be biopsy-proven melanoma. The patient underwent wide excision and sentinel node biopsy, which showed absence of residual melanoma. Two years later, the patient noticed a subcentimeter subcutaneous lump in his thigh. Repeat excisional biopsy showed involvement of the surrounding soft tissue, consistent with a satellite lesion. Follow-up combined PET/CT revealed satellite nodules around the primary lesion, enabling confirmation of subcutaneous metastatic disease. The patient was subsequently started on nivolumab, an anti-programmed cell death 1 (PD-1) immune checkpoint inhibitor that blocks PD-1 and is approved as a first-line treatment in patients with advanced metastatic melanoma. On the baseline scan prior to starting nivolumab, there were no CT findings that suggested metastatic disease, nor were there enlarged mediastinal or hilar lymph nodes. Five months after initiation of nivolumab treatment, the first follow-up chest CT scan was performed and showed new findings in the mediastinum and bilateral lungs. The patient remained asymptomatic during the treatment period. Furthermore, the subcutaneous metastatic disease remained stable during the treatment period, and no other site of metastatic disease was noted on follow-up CT scans obtained during the first 5 months of treatment. The patient had no prior history of infectious or occupational exposures. During the nivolumab treatment cycle, his pertinent laboratory values and physical examination findings were unremarkable.
February 2021
Radiographic Read Paradigms and the Roles of the Central Imaging Laboratory in Neuro-oncology Clinical Trials.Determination of therapeutic benefit in intracranial tumors is intimately dependent on serial assessment of radiographic images. The Response Assessment in Neuro-Oncology (RANO) criteria were established in 2010 to provide an updated framework to better characterize tumor response to contemporary treatments. Since this initial update a number of RANO criteria have provided some basic principles for the interpretation of changes on MR images; however, the details of how to operationalize RANO and other criteria for use in clinical trials are ambiguous and not standardized. In this review article designed for the neuro-oncologist or treating clinician, we outline essential steps for performing radiographic assessments by highlighting primary features of the Imaging Charter (referred to as the Charter for the remainder of this article), a document that describes the clinical trial imaging methodology and methods to ensure operationalization of the Charter into the workings of a clinical trial. Lastly, we provide recommendations for specific changes to optimize this methodology for neuro-oncology, including image registration, requirement of growing tumor for eligibility in trials of recurrent tumor, standardized image acquisition guidelines, and hybrid reader paradigms that allow for both unbiased measurements and more comprehensive interpretation.
February 2021
Using Digital Ethnography to Understand the Experience of Women With Pelvic Organ Prolapse.OBJECTIVE: To characterize the decision-making process and illness experience of women with pelvic organ prolapse (POP) using large-scale social media analysis. METHODS: Digital ethnographic analysis of online posts identified through data mining was performed. Grounded theory methodology was applied to 200 posts via traditional hand coding. To supplement our qualitative approach, we applied a Latent Dirichlet Allocation probabilistic topic modeling process to review the entire data set of identified posts to ensure thematic saturation.
February 2021
VIDEO: Dynamic Ultrasound for Snapping Hip Syndrome.OBJECTIVE: The purpose of this video article is to review the dynamic sonographic assessment of snapping hip syndrome. The video focuses on the extraarticular forms of snapping hip and discusses their possible causes, ultrasound features, and treatment options. The dynamic sonographic technique for evaluating snapping hip syndrome is shown with live scanning videos.
February 2021
Predicting Pathological Tumor Size in Prostate Cancer Based on Multiparametric Prostate Magnetic Resonance Imaging and Preoperative Findings.PURPOSE: Oncologic efficacy of focal therapies in prostate cancer depends heavily on accurate tumor size estimation. We aim to evaluate the agreement between radiologic tumor size and pathological tumor size, and identify predictors of pathological tumor size. MATERIALS AND METHODS: This single arm study cohort included all consecutive patients with biopsy proven prostate cancer and a corresponding PI-RADS®v2 3 or greater index tumor on multiparametric magnetic resonance imaging who subsequently underwent radical prostatectomy. Radiologic tumor size was defined as maximum tumor diameter on multiparametric magnetic resonance imaging and compared to whole mount histopathology tumor correlates. The difference between radiologic tumor size and pathological tumor size was assessed, and clinical, pathological and radiographic predictors of pathological tumor size were examined.
February 2021
Treatment of Post-Ablation Bronchopleural Fistula Using Percutaneous Synthetic Hydrogel Surgical Sealant: Initial Experience of Safety and Efficacy.PURPOSE: Bronchopleural fistula is a rare but serious complication of lung ablation, as it is difficult to treat and is associated with a high mortality rate. Standard therapy often relies on surgical pleurodesis, which can be particularly problematic in patients with poor baseline lung function. A minimally invasive treatment option for bronchopleural fistula may offer an alternative to surgery for appropriate patients. This case series describes the technique, safety and efficacy of percutaneously administered synthetic hydrogel surgical sealant in the treatment of post-ablation bronchopleural fistula in five patients. MATERIALS AND METHODS: Retrospective chart review was carried out in five consecutive patients identified to have had BPF after lung ablation between 2009 and 2017 who were treated with percutaneous administration of synthetic hydrogel surgical sealant using CT guidance.
February 2021
Influence of Phosphate Concentration on Amine, Amide, and Hydroxyl CEST Contrast.PURPOSE: To evaluate the influence of phosphate on amine, amide, and hydroxyl CEST contrast using Bloch-McConnell simulations applied to physical phantom data. METHODS: Phantom solutions of 4 representative metabolites with exchangeable protons-glycine (α-amine protons), Cr (η-amine protons), egg white protein (amide protons), and glucose (hydroxyl protons)-were prepared at different pH levels (5.6 to 8.9) and phosphate concentrations (5 to 80 mM). CEST images of the phantom were collected with CEST-EPI sequence at 3 tesla. The CEST data were then fitted to full Bloch-McConnell equation simulations to estimate the exchange rate constants. With the fitted parameters, simulations were performed to evaluate the intracellular and extracellular contributions of CEST signals in normal brain tissue and brain tumors, as well as in dynamic glucose-enhanced experiments.
January 2021
Eigenrank by Committee: Von-Neumann Entropy Based Data Subset Selection and Failure Prediction for Deep Learning Based Medical Image Segmentation.Manual delineation of anatomy on existing images is the basis of developing deep learning algorithms for medical image segmentation. However, manual segmentation is tedious. It is also expensive because clinician effort is necessary to ensure correctness of delineation. Consequently most algorithm development is based on a tiny fraction of the vast amount of imaging data collected at a medical center. Thus, selection of a subset of images from hospital databases for manual delineation - so that algorithms trained on such data are accurate and tolerant to variation, becomes an important challenge. We address this challenge using a novel algorithm. The proposed algorithm named 'Eigenrank by Committee' (EBC) first computes the degree of disagreement between segmentations generated by each DL model in a committee. Then, it iteratively adds to the committee, a DL model trained on cases where the disagreement is maximal. The disagreement between segmentations is quantified by the maximum eigenvalue of a Dice coefficient disagreement matrix a measure closely related to the Von Neumann entropy. We use EBC for selecting data subsets for manual labeling from a larger database of spinal canal segmentations as well as intervertebral disk segmentations. U-Nets trained on these subsets are used to generate segmentations on the remaining data. Similar sized data subsets are also randomly sampled from the respective databases, and U-Nets are trained on these random subsets as well. We found that U-Nets trained using data subsets selected by EBC, generate segmentations with higher average Dice coefficients on the rest of the database than U-Nets trained using random sampling (p < 0.05 using t-tests comparing averages). Furthermore, U-Nets trained using data subsets selected by EBC generate segmentations with a distribution of Dice coefficients that demonstrate significantly (p < 0.05 using Bartlett's test) lower variance in comparison to U-Nets trained using random sampling for all datasets. We believe that this lower variance indicates that U-Nets trained with EBC are more robust than U-Nets trained with random sampling.
January 2021
[Future of Cerebral Aneurysm Treatment].There has been an increasing role in the low invasive endovascular treatment of intracranial aneurysms. In addition to the detachable coils, the development of intracranial stents that are capable of repairing the parent artery itself has induced a significant treatment paradigm shift from open surgical to endovascular intervention. Recent evidence suggests that chronic inflammation plays a critical role in the process of intracranial aneurysm formation and rupture. It is, therefore, a natural evolution to seek drug treatments for intracranial aneurysms for growth or rupture prevention rather than any mechanical intervention. The authors review the current preclinical efforts on aneurysm drug treatments and prospective. Also covered is an emerging technology such as robotic endovascular treatment. The robotic system is capable of performing a subset of endovascular procedures such as stent-assisted aneurysm coiling. Although a lot of work needs to be done, remote health care is no longer science fiction.
January 2021
Call for a New Radiology Subspecialty in Imaging-Based Screening.Imaging-based screening has become a critical component of preventive care medicine, growing immensely over the past 50 years. Radiologists are at the center of this public health practice—we are the imaging experts—and yet we are underrepresented in the decision-making process that directs national screening practices. These decisions are largely made by primary care professionals and epidemiologists, who lack expertise in imaging. Here are two possible reasons for this: (1) Radiologists currently have minimal training in epidemiology and evidence development related to imaging-based screening, and (2) radiologists may be viewed as fundamentally biased in favor of imaging, resulting in a daily incentive toward more screening. As a solution, we propose a new radiology subspecialty—screening radiology—to help close the educational gap, untangle advocacy from science, and enable more effective radiology leadership in screening.
January 2021
Cardiac Magnetic Resonance Quantification of Structure-Function Relationships in Heart Failure.Classification of heart failure is based on the left ventricular ejection fraction (EF): preserved EF, midrange EF, and reduced EF. There remains an unmet need for further heart failure phenotyping of ventricular structure-function relationships. Because of high spatiotemporal resolution, cardiac magnetic resonance (CMR) remains the reference modality for quantification of ventricular contractile function. The authors aim to highlight novel frameworks, including theranostic use of ferumoxytol, to enable more efficient evaluation of ventricular function in heart failure patients who are also frequently anemic, and to discuss emerging quantitative CMR approaches for evaluation of ventricular structure-function relationships in heart failure.
January 2021
PI-RADS Version 2.1: A Critical Review, From the AJR Special Series on Radiology Reporting and Data Systems.PI-RADS version 2.1 updates the technical parameters for multiparametric MRI (mpMRI) of the prostate and revises the imaging interpretation criteria while maintaining the framework introduced in version 2. These changes have been considered an improvement, although some issues remain unresolved, and new issues have emerged. Areas for improvement discussed in this review include the need for more detailed mpMRI protocols with optimization for 1.5-T and 3-T systems; lack of validation of revised transition zone interpretation criteria and need for clarifications of the revised DWI and dynamic contrast-enhanced imaging criteria and central zone (CZ) assessment; the need for systematic evaluation and reporting of background changes in signal intensity in the prostate that can negatively affect cancer detection; creation of a new category for lesions that do not fit into the PI-RADS assessment categories (i.e., PI-RADS M category); inclusion of quantitative parameters beyond size to evaluate lesion aggressiveness; adjustments to the structured report template, including standardized assessment of the risk of extraprostatic extension; development of parameters for image quality and performance control; and suggestions for expansion of the system to other indications (e.g., active surveillance and recurrence).
