The early effect of COVID-19 on dental infections by neuroimaging in the emergency department setting.

OBJECTIVES: In early 2020, at COVID-19's onset in the United States, the American Dental Association recommended postponing elective dental procedures to minimize viral spread. Subsequently, concerns arose that this could result in increased dental infections and resultant emergency department visits. This study quantifies the number and severity of dental infections at the onset of the early COVID-19 outbreak in early 2020 in the Northeast United States resulting in emergency room visits and radiographic imaging compared to 2017-2019 with an analysis of geographic population characteristics. METHODS: Cross-sectional head and neck imaging performed at an East Coast hospital system was retrospectively reviewed for dental infections from March 2020 through December 2020, and compared to prior years 2017-2019. Inclusion criteria included radiology reporting of a dental infection, ranging in severity. Electronic medical records (EMR) and imaging reports were queried for patient characteristics and dental findings. RESULTS: There were 735 confirmed imaging reports of odontogenic infections. There was a significant increase in imaging reporting of odontogenic infections in the post-shutdown period. These were more frequently early-type infections, involved a higher proportion of male and non-white patients, and the patients were more often from disadvantaged zip codes when compared with prior years. CONCLUSIONS: These findings highlight the varying impact of outpatient dental office closures on different socioeconomic groups in the setting of a pandemic. Potential implications include increased morbidity and mortality for patients, as well as increased cost and resource allocations for the healthcare system.

Geographic Trends in Publications and Submissions in Radiology Journals: Decade Report (2010 - 2020).

RATIONALE AND OBJECTIVE: The Radiology Research Alliance (RRA) of the Association of University Radiologists (AUR) organized a task force to quantify geographic changes in submissions to and publications within radiology journals over time. MATERIALS AND METHODS: Twenty journals were selected: 7 US-based general, 4 European-based general, and 9 subspecialty radiology journals. Journals were solicited for submissions and publications based on country of origin from 2010 -2020. Regression models assessed changes over time across countries, and by continent, with an emphasis on the US and China, for each journal category. RESULTS: There were 104,679 publications and 92,446 submissions from 149 countries. Overall, there were significant increases in numbers of publications from Asia (R2 = 0.66, p <0.01), and specifically, China (R2 = 0.87, p <0.01). For US journals, there were increased numbers of publications from Asia (R2 = 0.72, p <0.01) and China (R2 = 0.98, p <0.01), but decreased numbers from North America (R2 = 0.41, p = 0.03). For European journals, there were increased numbers of publications from Asia (R2 = 0.79, p <0.01), North America (R2 = 0.75, p <0.01), and China (R2 = 0.82, p <0.01). For subspecialty journals, there were increased numbers of publications from North America (R2 = 0.38, p = 0.04) and China (R2 = 0.73, p <0.01). There was an acute COVID spike in submissions during 2020, with a continuous increase most notable in China (R2 = 0.96, p <0.01). CONCLUSION: In the last decade, the numbers of submissions to and publications within general and subspecialty US and European radiology journals have generally increased around the world, with the largest growth in Asia and in particular China.

Machine Learning and Improved Quality Metrics in Acute Intracranial Hemorrhage by Noncontrast Computed Tomography.

OBJECTIVE: The timely reporting of critical results in radiology is paramount to improved patient outcomes. Artificial intelligence has the ability to improve quality by optimizing clinical radiology workflows. We sought to determine the impact of a United States Food and Drug Administration-approved machine learning (ML) algorithm, meant to mark computed tomography (CT) head examinations pending interpretation as higher probability for intracranial hemorrhage (ICH), on metrics across our healthcare system. We hypothesized that ML is associated with a reduction in report turnaround time (RTAT) and length of stay (LOS) in emergency department (ED) and inpatient populations. MATERIALS AND METHODS: An ML algorithm was incorporated across CT scanners at imaging sites in January 2018. RTAT and LOS were derived for reports and patients between July 2017 and December 2017 prior to implementation of ML and compared to those between January 2018 and June 2018 after implementation of ML. A total of 25,658 and 24,996 ED and inpatient cases were evaluated across the entire healthcare system before and after ML, respectively. RESULTS: RTAT decreased from 75 to 69 minutes (P <0.001) at all facilities in the healthcare system. At the level 1 trauma center specifically, RTAT decreased from 67 to 59 minutes (P <0.001). ED LOS decreased from 471 to 425 minutes (P <0.001) for patients without ICH, and from 527 to 491 minutes for those with ICH (P = 0.456). Inpatient LOS decreased from 18.4 to 15.8 days for those without ICH (P = 0.001) and 18.1 to 15.8 days for those with ICH (P = 0.02). CONCLUSION: We demonstrated that utilization of ML was associated with a statistically significant decrease in RTAT. There was also a significant decrease in LOS for ED patients without ICH, but not for ED patients with ICH. Further evaluation of the impact of such tools on patient care and outcomes is needed.

A Case of Spinal Infectious Osteomyelitis Versus Gout: Advanced Imaging with Dual Energy CT.

A 67-year-old male presented to the hospital for lower back pain and left lower extremity radiculopathy. Although the patient was afebrile and white blood cell count was normal, MRI was concerning for discitis/osteomyelitis at L4-L5. Subsequently, the patient developed a right knee joint effusion and underwent an arthrocentesis that was notable for the presence of urate crystals. A systemic urate crystal arthropathy was proposed as a potential etiology for the patient's back pain and radiculopathy. Dual energy CT of the lumbar spine was performed, a technique which determines material composition by comparing the photon attenuation of the substance from two different x-ray energy levels. Results revealed the presence of monosodium urate crystals in the intervertebral discs. This technique is proposed as a noninvasive way to evaluate for gout in atypical locations or those difficult to sample and may replace an invasive intervertebral disc/endplate aspiration and/or biopsy. Dual energy CT should be considered in patients with elevated serum uric acid and concern for spinal involvement of gout.

The Utility of Imaging Parameters in Predicting Long-Term Clinical Improvement After Shunt Surgery in Patients with Idiopathic Normal Pressure Hydrocephalus.

OBJECTIVE: It is difficult to predict which patients with idiopathic normal pressure hydrocephalus (iNPH) will improve after shunt surgery. This study investigated the association between preoperative imaging parameters in patients with iNPH and long-term outcome after shunt placement. METHODS: Patients with iNPH who showed a response to large-volume cerebrospinal fluid drainage and subsequently underwent ventriculoperitoneal shunt surgery were reviewed. Long-term patient-reported outcomes were obtained by telephone interview. Preoperative computed tomography and/or magnetic resonance imaging were retrospectively reviewed to determine associations between imaging parameters and clinical outcome. RESULTS: The final analysis included 37 patients. The median duration between shunt surgery and telephone interview was 30 months (range, 12-56 months). Gait improvement after shunting was present more often in patients without focally dilated sulci (95% vs. 71%, P = 0.04), but a statistically significant relationship was not established after logistic regression. Patients with cognitive improvement after shunting had a higher preoperative Evans index (mean 0.41 vs. 0.36, P < 0.01), and Evans index was a predictor of cognitive improvement (odds ratio = 1.40, scale of 0.01, P = 0.01). CONCLUSIONS: Higher Evans index is a predictor of long-term cognitive improvement after shunt placement; however, no cutoff value demonstrates sufficient accuracy for the selection of shunt candidates. None of the evaluated imaging features was predictive of long-term gait or urinary improvement. The utility of imaging to predict a response to shunting is limited, and no imaging feature alone can be used to exclude patients from shunt surgery.

Utility of Artificial Intelligence Tool as a Prospective Radiology Peer Reviewer - Detection of Unreported Intracranial Hemorrhage.

RATIONALE AND OBJECTIVES: Misdiagnosis of intracranial hemorrhage (ICH) can adversely impact patient outcomes. The increasing workload on the radiologists may increase the chance of error and compromise the quality of care provided by the radiologists. MATERIALS AND METHODS: We used an FDA approved artificial intelligence (AI) solution based on a convolutional neural network to assess the prevalence of ICH in scans, which were reported as negative for ICH. We retrospectively applied the AI solution to all consecutive noncontrast computed tomography (CT) head scans performed at eight imaging sites affiliated to our institution. RESULTS: In the 6565 noncontrast CT head scans, which met the inclusion criteria, 5585 scans were reported to have no ICH ("negative-by-report" cases). We applied AI solution to these "negative-by-report" cases. AI solution suggested there were ICH in 28 of these scans ("negative-by-report" and "positive-by-AI solution"). After consensus review by three neuroradiologists, 16 of these scans were found to have ICH, which was not reported (missed diagnosis by radiologists), with a false-negative rate of radiologists for ICH detection at 1.6%. Most commonly missed ICH was overlying the cerebral convexity and in the parafalcine regions. CONCLUSION: Our study demonstrates that an AI solution can help radiologists to diagnose ICH and thus decrease the error rate. AI solution can serve as a prospective peer review tool for non-contrast head CT scans to identify ICH and thus minimize false negatives.

Investigation of Whole Spine MRI in the Emergency Department at Two Large Tertiary Care Academic Medical Centers in the United States.

RATIONALE AND OBJECTIVES: The impact of emergent whole spine magnetic resonance imaging (WS-MRI) on patient management has not been extensively studied to date. Here, we explore indications, results, and outcomes associated with WS-MRI performed through the emergency departments (EDs) of 2 large tertiary care, academic medical centers in the Northeastern United States. We hypothesize that given a relatively low barrier to entry, coupled with lack of appropriateness guidelines, a sizeable proportion of WS-MRI studies performed emergently do not result in spine findings necessitating inpatient admission for immediate treatment. MATERIALS AND METHODS: We retrospectively studied 335 adult patients (≥18 years) who underwent WS-MRI through the ED between 2016 and 2019. The demographic data collected included, age, sex, chief complaint, history of spine disease, and date and type of last spine imaging prior to ED presentation. Data compiled from the time of ED visit included WS-MRI result and patient disposition, including reason for hospital admission, by which patients were categorized into groups to allow for ease of comparisons. Hypergeometric tests were used to determine statistically significant associations between random discrete variables. RESULTS: Trauma was the most frequent chief complaint, comprising 35% (n = 117) of all presentations, followed by pain (25%, n = 84), motor deficit (16%, n = 55), sensory disturbance (12%, n = 41), bowel, and/or bladder dysfunction (9%, n = 30), and subjective or objective fevers with suspicion for spine infection (2%, n = 8). The largest proportion of WS-MRI studies revealed degenerative disc disease (DDD) as the principal result (41%, n = 139). 52% of all patients were either discharged directly from the ED (41%) or admitted for a non-spine issue after WS-MRI (11%); of these numbers, 61% underwent WS-MRI and no other imaging study in the ED. In patients who presented with a chief complaint of pain, DDD was often the principal WS-MRI finding (54%), albeit this association was not statistically significant. DDD, nonetheless, was positively associated with a discharge from the ED (P <0.001). Trauma was positively associated with fracture or ligamentous/soft tissue injury (P <0.001) on WS-MRI and hospital admission for a spine issue (P <0.01). CONCLUSION: That just under half of patients in our study were admitted for spine-related pathology suggests that WS-MRI is valuable in the emergent setting. At the same time, however, that over half of patients were not subsequently admitted for a spine-related issue points to the possibility of further refining which patients would benefit most from WS-MRI. WS-MRI may be less helpful in patients presenting with pain, though may be higher-yield in those with trauma, motor deficits, and bowel/bladder complaints. Although MRI is highly sensitive in ruling out emergent central nervous system pathology, given the resource-intensive nature of the test, it is prudent to carefully select which patients should undergo emergent WS-MRI, especially in instances when more cost-effective, alternative diagnostic approaches, including detailed neurological exam, computed tomography, or localized/targeted MRI, are possible.

Construction of a Machine Learning Dataset through Collaboration: The RSNA 2019 Brain CT Hemorrhage Challenge.

This dataset is composed of annotations of the five hemorrhage subtypes (subarachnoid, intraventricular, subdural, epidural, and intraparenchymal hemorrhage) typically encountered at brain CT.

Erratum: Construction of a Machine Learning Dataset through Collaboration: The RSNA 2019 Brain CT Hemorrhage Challenge.

[This corrects the article DOI: 10.1148/ryai.2020190211.].

Imaging of trauma of the spine.

The goal of imaging in spine trauma is to gauge the extent of bony, vascular, and neurologic compromise. Neurologic and mechanical stability are key pieces of information that must be efficiently communicated to the referring clinician. From immobilization and steroid therapy, to vascular repair and emergent surgical intervention, clinical outcomes of spine-injured patients depend on timely and well-chosen imaging studies. Multidetector computed tomography (CT) has essentially replaced radiography in clearance of the spine and is the gold standard in evaluation of the bony spinal column. Magnetic resonance imaging (MRI) is typically reserved for patients with neurologic deficits or for obtunded/impaired patients in whom the neurologic exam is not reliable, even in the absence of osseous injury on CT. MRI is the only available imaging modality that is able to clearly depict the internal architecture of the spinal cord, and, as such, has a central role in depicting parenchymal changes resulting from injury. Intramedullary edema and hemorrhage have been shown to correlate with the degree of neurologic deficit and prognosis. Moreover, advanced MRI techniques, such as diffusion and diffusion tensor imaging, have shifted the focus to determining structural and functional integrity of neural structures. Here, we review the role of imaging in spine trauma, as well as the key radiologic features of injury to the spinal column and spinal cord.

Practice Building: Achieving Growth Through Computed Tomographic Myelography-Based Stereotactic Body Radiation Therapy for Spinal Metastases.

Stereotactic body radiation therapy (SBRT) is as an effective method to treat spinal metastases. Imaging is a critical component in the workup of patients who undergo stereotactic radiation treatment. Computed tomographic myelography may be more accurate than magnetic resonance imaging in the delineation of neural elements during SBRT. The task we faced was to offer a standardized method to rapidly and safely obtain high-quality computed tomographic myelography as part of a robust spine SBRT program. In detailing our experience, we support the greater, active participation of radiologists in the multidisciplinary care of patients with spinal metastases, while encouraging other radiologists to foster similar collaborations at their own institutions.

Can anatomic level of injury on MRI predict neurological level in acute cervical spinal cord injury?

BACKGROUND: Determining neurological level of injury (NLI) is of paramount importance after spinal cord injury (SCI), although its accuracy depends upon the reliability of the neurologic examination. Here, we determine if anatomic location of cervical cord injury by MRI (MRI level of injury) can predict NLI in the acute traumatic setting. METHODS: A retrospective review was undertaken of SCI patients with macroscopic evidence of cervical cord injury from non-penetrating trauma, all of whom had undergone cervical spine MRI and complete neurologic testing. The recorded MRI information included cord lesion type (intra-axial edema, hemorrhage) and MRI locations of upper and lower lesion boundary, as well as lesion epicenter. Pearson correlation and Bland-Altman analyses were used to assess the relationship between MRI levels of injury and NLI. RESULTS: All five MRI parameters, namely (1) upper and (2) lower boundaries of cord edema, (3) lesion epicenter, and (4) upper and (5) lower boundaries of cord hemorrhage demonstrated statistically significant, positive correlations with NLI. The MRI locations of upper and lower boundary of hemorrhage were found to have the strongest correlation with NLI (r = 0.72 and 0.61, respectively; p < 0.01). A weaker (low to moderate) correlation existed between lower boundary of cord edema and NLI (r = 0.30; p < 0.01). Upper boundary of cord hemorrhage on MRI demonstrated the best agreement with NLI (mean difference 0.03 ± 0.73; p < 0.01) by Bland-Altman analysis. CONCLUSIONS: MRI level of injury has the potential to serve as a surrogate for NLI in instances where the neurologic examination is either unavailable or unreliable.

Embryology and Anatomy of the Jaw and Dentition.

Radiologists should possess working knowledge of the embryological development and anatomy of the jaw and dentition in order to aid in the diagnosis of both simple and complex disorders that affect them. Here, we review the elaborate process of odontogenesis, as well as describe in detail the anatomy of a tooth and its surrounding structures.

Dental Implants.

Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

Inflammatory Diseases of the Teeth and Jaws.

The teeth are unique in that they provide a direct pathway for spread of infection into surrounding osseous and soft tissue structures. Periodontal disease is the most common cause of tooth loss worldwide, referring to infection of the supporting structures of the tooth, principally the gingiva, periodontal ligament, cementum, and alveolar bone. Periapical disease refers to an infectious or inflammatory process centered at the root apex of the tooth, usually occurring when deep caries infect the pulp chamber and root canals. We review the pathogenesis, clinical features, and radiographic findings (emphasis on computed tomography) in periodontal and periapical disease.

Diminished visibility of cerebral venous vasculature in multiple sclerosis by susceptibility-weighted imaging at 3.0 Tesla.

Multiple sclerosis (MS) is a disease of the central nervous system characterized by widespread demyelination, axonal loss and gliosis, and neurodegeneration; susceptibility-weighted imaging (SWI), through the use of phase information to enhance local susceptibility or T2* contrast, is a relatively new and simple MRI application that can directly image cerebral veins by exploiting venous blood oxygenation. Here, we use high-field SWI at 3.0 Tesla to image 15 patients with clinically definite relapsing-remitting MS and to assess cerebral venous oxygen level changes. We demonstrate significantly reduced visibility of periventricular white matter venous vasculature in patients as compared to control subjects, supporting the concept of a widespread hypometabolic MS disease process. SWI may afford a noninvasive and relatively simple method to assess venous oxygen saturation so as to closely monitor disease severity, progression, and response to therapy.

Rho/ROCK and MAPK signaling pathways are involved in glioblastoma cell migration and proliferation.

BACKGROUND: Glioblastoma multiforme (GBM) remains the most aggressive and frequently occurring brain neoplasm. Members of the Rho family of small GTP-binding proteins, including Rho, Rac, and Cdc42, have been shown to participate in cell growth differentiation and motility. The mitogen-activated protein kinase (MAPK) pathway, which includes extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), has been shown to regulate cell growth, differentiation and motility. Here, the involvement of the Rho and Rho-associated protein kinase (ROCK) pathway, along with MAPK, was investigated to determine their roles in GBM cell migration and proliferation. MATERIALS AND METHODS: In vitro studies utilized the human malignant glioblastoma cell line LN-18. The cells were treated with Y-27632, a ROCK inhibitor, and U0126, an upstream MAPK kinase inhibitor (MEK), alone or in combination with one another. Immunoblotting analysis established the levels of phosphorylated ERK1/2. Cell migration was determined by radial migration assay and cell proliferation by MTT. RESULTS: Y-27632 reduced phosphorylation of ERK1/2 at 0.5 and 2 h. U0126 in combination with Y-27632 led to a more pronounced repression of platelet-derived growth factor (PDGF)- or fibronectin (FN)-induced ERK1/2 activation than U0126 treatment alone. Y-27632 treatment for 24 h suppressed GBM cell migration and resulted in a reduction in LN-18 cell proliferation. Furthermore, PDGF and FN-induced cell proliferation was suppressed by pre-treatment with Y-27632 or U0126, with the greatest reduction achieved by a combination of the two inhibitors. CONCLUSION: Rho/ROCK signaling is involved in GBM cell migration and proliferation, and this pathway may be linked to ERK signaling.

Seven-Tesla magnetic resonance imaging: new vision of microvascular abnormalities in multiple sclerosis.

BACKGROUND: Although the role of vascular pathology in multiple sclerosis (MS) lesions was suggested long ago, the derivation of these lesions from the vasculature has been difficult to assess in vivo. Ultrahigh-field (eg, 7-T) magnetic resonance imaging (MRI) has become a tool for assessing vascular involvement in MS lesions owing to markedly increased image resolution and susceptibility contrast of venous blood. OBJECTIVE: To describe the perivenous association of MS lesions on high-resolution and high-contrast 7-T susceptibility-sensitive MRI. DESIGN: Case study. SETTING: University hospital. PATIENTS: Two women with clinically definite relapsing-remitting MS. RESULTS: We demonstrated markedly enhanced detection of unique microvascular involvement associated with most of the visualized MS lesions with abnormal signals on and around the venous wall on 7-T compared with 3-T MRI. CONCLUSIONS: These findings, which have never been shown on conventional fields of MRI, not only allow for direct evidence of vascular pathogenesis in MS in vivo but also have important implications for monitoring lesion activity and therapeutic response.

Gene expression profiling of metastatic brain cancer.

Gene expression profiling of metastatic brain tumors from primary lung adenocarcinoma, using a 17k-expression array, revealed that 1561 genes were consistently altered. Further functional classification placed the genes into seven categories: cell cycle and DNA damage repair, apoptosis, signal transduction molecules, transcription factors, invasion and metastasis, adhesion, and angiogenesis. Genes involved in apoptosis, such as caspase 2 (CASP2), transforming growth factor-beta inducible early gene (TIEG), and neuroprotective heat shock protein 70 (Hsp70) were underexpressed in metastatic brain tumors. Alterations in Rho GTPases (ARHGAP26, ARHGAP1), as well as down-regulation of the metastasis suppressor gene KiSS-1 were noted, which may contribute to tumor aggression. Overexpression of the invasion-related gene neurofibromatosis 1 (NF1), and angiogenesis-related genes vascular endothelial growth factor-B (VEGF-B) and placental growth factor (PGF) was also evidenced. Brain-specific angiogenesis inhibitors 1 and 3 (BAI1 and BAI3) were underexpressed as well. Examination of cell-adhesion and migration-related genes revealed an increased expression of integrins and extracellular matrices collagen and laminin. The study also showed alterations in p53 protein-associated genes, among these increased gene expression of p53, up-regulation of Reprimo or candidate mediator of the p53-dependent G2-arrest, down-regulation of p53-regulated apoptosis-inducing protein 1 (p53AIP1), decreased expression of tumor protein inducible nuclear protein 1 (p53DINP1), and down-regulation of Mdm4 (MDMX). The results demonstrated that genes involved in adhesion, motility, and angiogenesis were consistently up-regulated in metastatic brain tumors, while genes involved in apoptosis, neuroprotection, and suppression of angiogenesis were markedly down-regulated, collectively making these cancer cells prone to metastasis.

The antiproliferative effect of Quercetin in cancer cells is mediated via inhibition of the PI3K-Akt/PKB pathway.

BACKGROUND: The tumor suppressor gene PTEN, mutated in 40-50% of patients with brain tumors, especially those with glioblastomas, maps to chromosome 10q23.3 and encodes a dual-specificity phosphatase. PTEN exerts its effects partly via inhibition of protein tyrosine kinase B (Akt/Protein Kinase B), which is involved in the phosphatidylinositol (PtdIns) 3-kinase (PI3K)-mediated cell-survival pathway. The naturally occurring bioflavonoid Quercetin (Qu) shares structural homology with the commercially available selective PI3K inhibitor, LY 294002 (LY). Here, the effects of Qu on the Akt/PKB pathway were evaluated. MATERIALS AND METHODS: The human breast carcinoma cell lines, HCC1937, with homozygous deletion of the PTEN gene, and T47D, with intact PTEN, were time-treated with Qu or LY and analyzed for activated levels of Akt by measuring phospho-Akt (p-Akt) levels using immunoblotting analysis. To detect p-Akt, the T47D cells were treated with EGF prior to treatment with or without Qu or LY Cell proliferation after 24-h treatment with Qu or LY was quantified by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: Treatment with Qu (25 microM) for 0.5, 1 and 3 h completely suppressed constitutively activated Akt/PKB phosphorylation at Ser-473 in HCC1937 cells. Pre-exposing T47D cells to Qu (25 microM) or LY (10 microM) abrogated EGF-induced Akt/PKB phosphorylation at Ser-473. Both Qu (100 microM) and LY (50 microM) treatments for 24 h significantly decreased cell proliferation, as shown by the MTT assay. CONCLUSION: Pharmacologically safe doses of the naturally occurring bioflavonoid Qu inhibit the PI3K-Akt/PKB pathway, in a manner similar to that of the commercially available LY. Overall, our results indicated that Qu inhibited the constitutively activated-Akt/PKB pathway in PTEN-null cancer cells, and suggest that this compound may have therapeutic benefit against tumorigenesis and cancer progression.