Dose development in sinonasal imaging over the last decade - a retrospective patient study.

BACKGROUND: Computed tomography (CT) has become the primary imaging modality for visualization of the paranasal sinuses. In this retrospective, single center patient study the radiation dose development in the past 12 years in CT imaging of the paranasal sinuses was assessed. METHODS: The computed tomography dose index (CTDIVol) and dose length product (DLP) of a total of 1246 patients (average age: 41 ± 18 years, 361 females, 885 males) were evaluated, who received imaging of the paranasal sinuses either for chronic sinusitis diagnostic, preoperatively or posttraumatically. Scans were performed on three different CT scanners (Somatom Definition AS, Somatom Definition AS+, Somatom Force, all from Siemens Healthineers) and on one CBCT (Morita) ranging from 2010 to 2022. Reconstruction techniques were filtered back projection and three generations of iterative reconstruction (IRIS, SAFIRE, ADMIRE, all from Siemens Healthineers). Group comparisons were performed using either parametrical (ANOVA) or non-parametrical tests (Kruskal-Wallis Test), where applicable. RESULTS: Over the past 12 years, there was a 73%, 54%, and 66% CTDIVol reduction and a significant (p < 0.001) 72%, 33%, and 67% DLP reduction in assessing the paranasal sinuses for chronic sinusitis, preoperatively and posttraumatically, respectively. CONCLUSION: Technological developments in CT imaging, both hardware and software based, have led to a significant reduction in dose exposure in recent years. Particularly in imaging of the paranasal sinuses, the reduction of radiation exposure is of great interest due to the often young patient age and radiation-sensitive organs in the area of radiation exposure.

Computed Tomography Urography: State of the Art and Beyond.

Computed Tomography Urography (CTU) is a multiphase CT examination optimized for imaging kidneys, ureters, and bladder, complemented by post-contrast excretory phase imaging. Different protocols are available for contrast administration and image acquisition and timing, with different strengths and limits, mainly related to kidney enhancement, ureters distension and opacification, and radiation exposure. The availability of new reconstruction algorithms, such as iterative and deep-learning-based reconstruction has dramatically improved the image quality and reducing radiation exposure at the same time. Dual-Energy Computed Tomography also has an important role in this type of examination, with the possibility of renal stone characterization, the availability of synthetic unenhanced phases to reduce radiation dose, and the availability of iodine maps for a better interpretation of renal masses. We also describe the new artificial intelligence applications for CTU, focusing on radiomics to predict tumor grading and patients' outcome for a personalized therapeutic approach. In this narrative review, we provide a comprehensive overview of CTU from the traditional to the newest acquisition techniques and reconstruction algorithms, and the possibility of advanced imaging interpretation to provide an up-to-date guide for radiologists who want to better comprehend this technique.

Acute haemorrhage rate in 28,000 Out-of-Hours CT heads.

OBJECTIVES: The aim of this paper is to assess the acute haemorrhage rate in patients who had CT head investigation out-of-hours with and without trauma and compare the rates of haemorrhage between warfarin and DOACs, at a busy teritary teaching hospital. METHODS: All CT heads performed between January 2008 and December 2019 were identified from the radiology information system (RIS) at Sheffield Teaching Hospitals (STH), with the requesting information being available from January 2015. The clinical information was assessed for the mention of trauma or anticoagulation, and the reports were categorised into acute and non-acute findings. RESULTS: Between 2008 and 2019 the number of scans increased by 63%, with scans performed out of hours increasing by 278%. Between 2015 and 2019, the incidence of acute ICH was similar over the 5-year period, averaging at 6.9% and ranging from 6.1 to 7.6%. The rate of detection of acute haemorrhage following trauma was greater in those not anticoagulated (6.8%), compared with patients on anticoagulants such as warfarin (5.2%) or DOACs (2.8%). CONCLUSIONS: Over 12 years, there has been a significant increase in the number of CT heads performed at STH. The rate of ICH has remained steady over the last 5 years indicating a justified increase in imaging demand. However, the incidence of ICH in patients prescribed DOACs is lower than the general population and those on warfarin. ADVANCES IN KNOWLEDGE: This finding in a large centre should prompt discussion of the risk of bleeding with DOACs in relation to CT head imaging guidelines.

Fusion of Preoperative and Postoperative Imaging May Predict the Diagnostic Yield of Stereotactic Needle Brain Biopsies.

BACKGROUND: Stereotactic needle brain biopsy is a commonly used neurosurgical procedure. However, up to 15% of biopsies result in undiagnostic pathology reports. Repeat biopsy or continued management without a diagnosis are often considered after undiagnostic biopsies. There have been no reports about the role of postoperative imaging in predicting the diagnostic yield of stereotactic biopsies. METHODS: We retrospectively assessed all stereotactic biopsies performed over an 11-year period. We performed fusion of immediate postoperative computed tomography (CT) with preoperative MRI, to document whether the air bubble in the postoperative CT was located within the targeted lesion. We then evaluated the association of this fusion-based accuracy assessment with the diagnostic yield of the biopsy. RESULTS: Fewer than 5% of biopsies did not have an air bubble on postoperative CT. A total of 226 biopsies were performed for 219 patients. In our sample, 213 of 226 biopsies were accurate (94.2% accuracy rate), and 203 of 226 biopsies gave a definitive diagnosis (89.8% diagnostic rate). In those cases where the fusion was accurate, the diagnostic rate was 93.9%. When the fusion was inaccurate, the diagnostic rate was only 23.1% (odds ratio 51.5, 95% confidence interval 12.6-210.44, P < 0.001). Of all patient, imaging, surgical, and admission parameters, the only parameter that correlated with diagnostic outcome of the biopsy was the fusion construct accuracy. CONCLUSIONS: Fusion of immediate postoperative CT with preoperative imaging is predictive of the diagnostic rate. In cases where the pathology report following a biopsy is not diagnostic, this fusion may be useful in making decisions regarding repeat biopsy or considering other diagnostic options.

A Novel CT-based Radiomics-Clinical Nomogram for the Prediction of Short-Term Prognosis in Deep Intracerebral Hemorrhage.

OBJECTIVE: To develop and validate a radiomics-clinical nomogram for the prediction of short-term prognosis in patients with deep intracerebral hemorrhage (DICH) on admission. METHODS: A total of 326 patients with DICH (development cohort = 187; testing cohort = 81; validation cohort = 58) were retrospectively included. Radiomics features were extracted from computed tomography (CT) images and optimal features were selected using least absolute shrinkage and selection operator regression. A radiomics score (R-score) was developed using the optimal features. Univariate and multivariate analyses were used to determine independent risk factors for poor outcomes at 30 days. A radiomics-clinical (R-C) nomogram was developed and validated in the three cohorts. Receiver operating characteristic curve (ROC), calibration curve and decision curve analyses were conducted to evaluate the performances of the R-C nomogram. RESULTS: Only 4 of 396 radiomics features were selected to develop R-scores. Age, onset-to-CT time, Glasgow Coma Scale score, midline shift, and R-score were detected as independent predictors of poor prognosis of DICH. The R-C nomogram was developed by the independent predictors and showed acceptable discrimination with areas under ROCs of 0.80, 0.79, and 0.70 in the development, testing and validation cohorts, respectively. The R-C nomogram showed good agreement between the predicted probability and the actual probability (all P > 0.05) and clinical applicability in each cohort. CONCLUSIONS: The R-C nomogram is a stable and effective tool for predicting the short-term prognosis of DICH, which may help clinicians perform individual risk assessments and make decisions for patients with DICH.

Attenuation Value in Adrenal Incidentalomas: A Longitudinal Study.

Context: A tendency to grow has been reported in adrenal incidentalomas. However, long-term data regarding attenuation value, a measure of lipid content, are not available. Aim: This study aims to collect radiological data (diameter in mm and attenuation value in Hounsfield units, HU) with computed tomography (CT) in adrenal incidentalomas, in order to compare baseline characteristics with the last follow-up imaging. Design: This is a longitudinal study which included patients with a new diagnosis of adrenal incidentaloma, evaluated from January 2002 to June 2020. Setting: Referral University-Hospital center. Patients: Two hundred seventy-seven patients with 355 different cortical adenomas (baseline group) were evaluated at the first outpatient visit; the follow-up cohort consists of 181 patients with 234 adenomas (12-175 months after baseline). Inclusion criteria were conservative management and radiological features able to minimize malignancy or risk of progression. Main Outcome Measure: CT modification according to endocrine function: autonomous cortisol secretion (ACS) if cortisol >50 nmol/L after 1-mg dexamethasone test (DST). Results: At baseline CT, mean diameter was 18.7 mm and attenuation value was 0.8 HU (higher in ACS, 66 cases >10 HU), without modification in early imaging (12-36 months). The size increased over time (r = 0.289), achieving the largest differences after at least 60 months of follow-up (mean diameter, +2 mm; attenuation value, -4 HU), combined with a reduction in the attenuation value (r = -0.195, especially in patients with ACS). Lipid-poor adenomas (>10 HU) presented a reduced cortisol suppression after 1-mg DST, an increase in size and the largest decrease in attenuation value during follow-up. Univariate analysis confirmed that larger adenomas presented reduced suppression after DST and increase in size during follow-up. Conclusions: Growth is clinically modest in adrenal incidentaloma: the first follow-up CT 5 years after baseline is a reasonable choice, especially in ACS. Mean density is increased in patients with ACS and overt hypercortisolism. Mean density reduces during follow-up in all adrenal adenomas, suggesting an increase in lipid content, especially in those with ACS.

Trends in Management of Simple Febrile Seizures at US Children's Hospitals.

OBJECTIVE: We sought to measure trends in evaluation and management of children with simple febrile seizures (SFSs) before and after the American Academy of Pediatrics updated guidelines published in 2011. METHODS: In this retrospective, cross-sectional analysis, we used the Pediatric Health Information System database comprising 49 tertiary care pediatric hospitals in the United States from 2005 to 2019. We included children aged 6 to 60 months with an emergency department visit for first SFS identified using codes from the International Classification of Diseases, Ninth Revision, and International Classification of Diseases 10th Revision. RESULTS: We identified 142 121 children (median age 21 months, 42.4% female) with an emergency department visit for SFS. A total of 49 668 (35.0%) children presented before and 92 453 (65.1%) after the guideline. The rate of lumbar puncture for all ages declined from 11.6% (95% confidence interval [CI], 10.8% to 12.4%) in 2005 to 0.6% (95% CI, 0.5% to 0.8%) in 2019 (P < .001). Similar reductions were noted in rates of head computed tomography (10.6% to 1.6%; P < .001), complete blood cell count (38.8% to 10.9%; P < .001), hospital admission (19.2% to 5.2%; P < .001), and mean costs ($1523 to $601; P < .001). Reductions in all outcomes began before, and continued after, the publication of the American Academy of Pediatrics guideline. There was no significant change in delayed diagnosis of bacterial meningitis (preperiod 2 of 49 668 [0.0040%; 95% CI, 0.00049% to 0.015%], postperiod 3 of 92 453 [0.0032%; 95% CI, 0.00066% to 0.0094%]; P = .99). CONCLUSIONS: Diagnostic testing, hospital admission, and costs decreased over the study period, without a concomitant increase in delayed diagnosis of bacterial meningitis. These data suggest most children with SFSs can be safely managed without lumber puncture or other diagnostic testing.

Current and Emerging Tools for Hepatocellular Carcinoma Surveillance.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Early detection of HCC enables patients to avail curative therapies that can improve patient survival. Current international guidelines advocate for the enrollment of patients at high risk for HCC, like those with cirrhosis, in surveillance programs that perform ultrasound every 6 months. In recent years, many studies have further characterized the utility of established screening strategies and have introduced new promising tools for HCC surveillance. In this review, we provide an overview of the most promising new imaging modalities and biomarkers for the detection of HCC. We discuss the role of imaging tools like ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) in the early detection of HCC, and describe recent innovations which can potentially enhance their applicability, including contrast enhanced ultrasound, low-dose CT scans, and abbreviated MRI. Next, we outline the data supporting the use of three circulating biomarkers (i.e., alpha-fetoprotein [AFP], AFP lens culinaris agglutinin-reactive fraction, and des-gamma-carboxy prothrombin) in HCC surveillance, and expand on multiple emerging liquid biopsy biomarkers, including methylated cell-free DNA (cfDNA), cfDNA mutations, extracellular vesicles, and circulating tumor cells. These promising new imaging modalities and biomarkers have the potential to improve early detection, and thus improve survival, in patients with HCC.

Computed tomography features of COVID-19 in children: A systematic review and meta-analysis.

BACKGROUND: There are few reports on the chest computed tomography (CT) imaging features of children with coronavirus disease 2019 (COVID-19), and most reports involve small sample sizes. OBJECTIVES: To systematically analyze the chest CT imaging features of children with COVID-19 and provide references for clinical practice. DATA SOURCES: We searched PubMed, Web of Science, and Embase; data published by Johns Hopkins University; and Chinese databases CNKI, Wanfang, and Chongqing Weipu. METHODS: Reports on chest CT imaging features of children with COVID-19 from January 1, 2020 to August 10, 2020, were analyzed retrospectively and a meta-analysis carried out using Stata12.0 software. RESULTS: Thirty-seven articles (1747 children) were included in this study. The heterogeneity of meta-analysis results ranged from 0% to 90.5%. The overall rate of abnormal lung CT findings was 63.2% (95% confidence interval [CI]: 55.8%-70.6%), with a rate of 61.0% (95% CI: 50.8%-71.2%) in China and 67.8% (95% CI: 57.1%-78.4%) in the rest of the world in the subgroup analysis. The incidence of ground-glass opacities was 39.5% (95% CI: 30.7%-48.3%), multiple lung lobe lesions was 65.1% (95% CI: 55.1%-67.9%), and bilateral lung lesions was 61.5% (95% CI: 58.8%-72.2%). Other imaging features included nodules (25.7%), patchy shadows (36.8%), halo sign (24.8%), consolidation (24.1%), air bronchogram signs (11.2%), cord-like shadows (9.7%), crazy-paving pattern (6.1%), and pleural effusion (9.1%). Two articles reported 3 cases of white lung, another reported 2 cases of pneumothorax, and another 1 case of bullae. CONCLUSIONS: The lung CT results of children with COVID-19 are usually normal or slightly atypical. The lung lesions of COVID-19 pediatric patients mostly involve both lungs or multiple lobes, and the common manifestations are patchy shadows, ground-glass opacities, consolidation, partial air bronchogram signs, nodules, and halo signs; white lung, pleural effusion, and paving stone signs are rare. Therefore, chest CT has limited value as a screening tool for children with COVID-19 and can only be used as an auxiliary assessment tool.

Perfusion Imaging and Clinical Outcome in Acute Ischemic Stroke with Large Core.

OBJECTIVE: Mechanical thrombectomy (MT) is not recommended for acute stroke with large vessel occlusion (LVO) and a large volume of irreversibly injured tissue ("core"). Perfusion imaging may identify a subset of patients with large core who benefit from MT. METHODS: We compared two cohorts of LVO-related patients with large core (>50 ml on diffusion-weighted-imaging or CT-perfusion using RAPID), available perfusion imaging, and treated within 6 hours from onset by either MT + Best Medical Management (BMM) in one prospective study, or BMM alone in the pre-MT era from a prospective registry. Primary outcome was 90-day modified Rankin Scale ≤2. We searched for an interaction between treatment group and amount of penumbra as estimated by the mismatch ratio (MMRatio = critical hypoperfusion/core volume). RESULTS: Overall, 107 patients were included (56 MT + BMM and 51 BMM): Mean age was 68 ± 15 years, median core volume 99 ml (IQR: 72-131) and MMRatio 1.4 (IQR: 1.0-1.9). Baseline clinical and radiological variables were similar between the two groups, except for a higher intravenous thrombolysis rate in the BMM group. The MMRatio strongly modified the clinical outcome following MT (pinteraction < 0.001 for continuous MMRatio); MT was associated with a higher rate of good outcome in patients with, but not in those without, MMRatio>1.2 (adjusted OR [95% CI] = 6.8 [1.7-27.0] vs 0.7 [0.1-6.2], respectively). Similar findings were present for MMRatio ≥1.8 in the subgroup with core ≥70 ml. Parenchymal hemorrhage on follow-up imaging was more frequent in the MT + BMM group regardless of the MMRatio. INTERPRETATION: Perfusion imaging may help select which patients with large core should be considered for MT. Randomized studies are warranted. ANN NEUROL 2021;90:417-427.

Review of cardiovascular imaging in the Journal of Nuclear Cardiology 2020: positron emission tomography, computed tomography, and magnetic resonance.

Although the year 2020 was different from other years in many respects, the Journal of Nuclear Cardiology published excellent articles pertaining to imaging in patients with cardiovascular disease due to the dedication of the investigators in our field all over the world. In this review, we will summarize a selection of these articles to provide a concise review of the main advancements that have recently occurred in the field and provide the reader with an opportunity to review a wide selection of articles. We will focus on publications dealing with positron emission tomography, computed tomography, and magnetic resonance and hope that you will find this review helpful.

Developments in Treatment Methodologies Using Dendrimers for Infectious Diseases.

Dendrimers comprise a specific group of macromolecules, which combine structural properties of both single molecules and long expanded polymers. The three-dimensional form of dendrimers and the extensive possibilities for use of additional substrates for their construction creates a multivalent potential and a wide possibility for medical, diagnostic and environmental purposes. Depending on their composition and structure, dendrimers have been of interest in many fields of science, ranging from chemistry, biotechnology to biochemical applications. These compounds have found wide application from the production of catalysts for their use as antibacterial, antifungal and antiviral agents. Of particular interest are peptide dendrimers as a medium for transport of therapeutic substances: synthetic vaccines against parasites, bacteria and viruses, contrast agents used in MRI, antibodies and genetic material. This review focuses on the description of the current classes of dendrimers, the methodology for their synthesis and briefly drawbacks of their properties and their use as potential therapies against infectious diseases.

Appendicitis in the COVID-19 era: a modern challenge for experienced hands.

INTRODUCTION: The first wave of COVID-19 was accompanied by global uncertainty. Delayed presentation of patients to hospitals ensued, with surgical pathologies no exception. This study aimed to assess whether delayed presentations resulted in more complex appendicectomies during the first wave of COVID-19. METHODS: Operation notes for all presentations of appendicitis (n=216) within a single health board (three hospitals) during two three-month periods (control period (pre-COVID) vs COVID pandemic) were analysed, and the severity of appendicitis was recorded as per the American Association for the Surgery of Trauma (AAST) grading system. RESULTS: Presentations of appendicitis were delayed during the COVID period with a median duration of symptoms prior to hospital attendance of two days versus one day (p=0.003) with individuals presenting with higher median white cell count than during the control period (14.9 vs 13.3, p=0.031). Use of preoperative CT scanning (OR 3.013, 95% CI 1.694-5.358, p<0.001) increased significantly. More complex appendicectomies (AAST grade >1) were performed (OR 2.102, 95% CI 1.155-3.826, p=0.015) with a greater consultant presence during operations (OR 4.740, 95% CI 2.523-8.903, p<0.001). Despite the greater AAST scores recorded during the COVID period, no increase in postoperative complications was observed (OR 1.145, 95% CI 0.404-3.244, p=0.798). CONCLUSIONS: Delayed presentations during the COVID-19 pandemic were associated with more complex cases of appendicitis. Important lessons can be learnt from the changes in practice employed as a result of this global pandemic.

Current Status and Future Prospects of Transcatheter Mitral Valve Replacement: JACC State-of-the-Art Review.

Mitral regurgitation (MR) is the most prevalent valvular heart disease and, when left untreated, it confers a poorer prognosis. Catheter-based repair therapies face some limitations like their applicability on challenging anatomies and the potential recurrence of significant MR over time. Transcatheter mitral valve replacement (TMVR) has emerged as a less invasive approach potentially overcoming some of the current limitations associated with transcatheter mitral valve repair. Several devices are under clinical investigation, and a growing number of systems allow for a fully percutaneous transfemoral approach. In this review, the authors aimed to delineate the main challenges faced by the TMVR field, to highlight the key aspects for procedural planning, and to describe the clinical results of the TMVR systems under clinical investigation. Finally, they also discuss what the future perspectives are for this emerging field.

Evaluation of the utility of early routine computed tomography angiography in subarachnoid hemorrhage patient outcomes.

OBJECTIVES: The role of an early CTA approach in neurologically stable patients with nontraumatic SAH has not been assessed. This study explored the use of CTA in clinically stable SAH patients to pre-emptively identify cerebral vasospasm, to evaluate whether this approach is associated with improved clinical outcomes. METHODS: We conducted a retrospective chart review of SAH patients presenting between July 2007 and December 2016 in a single academic center. Patients were divided into two groups: (1) Early CTA (stable patients who underwent a CTA between days 5-8 post-SAH), and (2) Standard Protocol. The co-primary outcomes were a composite of the mRS at discharge and last clinical follow-up (good = 0-2; poor = 3-6). A multivariable binary logistic regression was conducted to compare both groups against outcomes, controlling for potential confounders. RESULTS: A total of 415 patients were included, 103 (24.8%) with early CTA, and 312 (75.2%) undergoing the standard protocol; the mean age was 57 years and 248 (59.8%) patients were female. Patients in the early CTA group had a higher modified Fisher grade (3-4) (87.4% vs 63.1%; p < 0.02). The multivariable analysis showed that early CTA was independently associated with lower poor outcomes at discharge (OR = 0.21, 95% CI 0.07-0.61, p = 0.004). Plus, vasospasm detection was associated with an increased risk of poor outcomes (OR = 4.77, 95% CI 1.41 - 16.10, p = 0.01). Early CTA was not associated with outcomes at clinical follow-up. CONCLUSION: The early CTA surveillance approach was associated with better functional outcomes at discharge when compared to the current imaging standard practice.

Predicting neurosurgical clearance in the polytrauma patient with concomitant traumatic brain injury.

The goal of this study is to develop a model based on previously used prognostic predictors in traumatic brain injury (TBI) patients with polytrauma, which will facilitate the decision-making of whether to clear these patients for non-cranial surgery. Data of eligible patients was obtained from a trauma database at a Level I trauma and academic tertiary referral center in the United States. The number of days seen by the neurosurgical service prior to clearance, injury severity score (ISS), post-trauma day 0 (PTD 0) of Glasgow Coma Score (GCS), intracranial pressure (ICP) score and computed tomography (CT) score, as well as the changes in GCS, ICP score and CT score between PTD 0 and day of clearance were the variables used in developing the model. The Neurosurgical Clearance Model (NCM) was developed using data from 50 patients included in the study. Patients were cleared by neurosurgeons 1.6 days later than it would appear possible based on a retrospective review of the patients' clinical conditions. A single model equation was developed, the ultimate result of which is a clearance probability value. The best cutoff clearance probability value was found to be 0.584 (or 58.4%) using Receiver Operator Characteristic curve analysis. Our data suggests that neurosurgeons are risk-averse in clearing polytrauma patients for non-cranial surgery. This pilot NCM, if reproduced and validated by other groups and in larger prospective studies, may become a useful tool to assist clinicians in this often-difficult decision-making process.

Trends in utilization of whole-body computed tomography in blunt trauma after MVC: Analysis of the Trauma Quality Improvement Program database.

BACKGROUND: The use of whole-body computed tomography (WBCT) in awake, clinically stable injured patients is controversial. It is associated with unnecessary radiation exposure and increased cost. We evaluate use of computed tomography (CT) imaging during the initial evaluation of injured patients at American College of Surgeons Levels I and II trauma centers (TCs) after blunt trauma. METHODS: We identified adult blunt trauma patients after motor vehicle crash (MVC) from the American College of Surgeons Trauma Quality Improvement Program (TQIP) database between 2007 and 2016 at Level I or II TCs. We defined awake clinically stable patients as those with systolic blood pressure of 100 mm Hg or higher with a Glasgow Coma Scale score of 15. Computed tomography imaging had to have been performed within 2 hours of arrival. Whole-body computed tomography was defined as simultaneous CT of the head, chest and abdomen, and selective CT if only one to two aforementioned regions were imaged. Patients were stratified by Injury Severity Score (ISS). RESULTS: There were 217,870 records for analysis; 131,434 (60.3%) had selective CT, and 86,436 (39.7%) had WBCT. Overall, there was an increasing trend in WBCT utilization over the study period (p < 0.001). In patients with ISS less than 10, WBCT was utilized more commonly at Level II versus Level I TCs in patients discharged from the emergency department (26.9% vs. 18.3%, p < 0.001), which had no surgical procedure(s) (81.4% vs. 80.3%, p < 0.001) and no injury of the head (53.7% vs. 52.4%, p = 0.008) or abdomen (83.8% vs. 82.1%, p = 0.001). The risk-adjusted odds of WBCT was two times higher at Level II TC vs. Level I (odds ratio, 1.88; 95% confidence interval 1.82-1.94; p < 0.001). CONCLUSION: Whole-body computed tomography utilization is increasing relative to selective CT. This increasing utilization is highest at Level II TCs in patients with low ISSs, and in patients without associated head or abdominal injury. The findings have implications for quality improvement and cost reduction. LEVEL OF EVIDENCE: Care management, Level IV.

A rare case of spontaneous otogenic pneumocephalus with pictorial illustration of temporal evolution.

Pneumocephalus is commonly seen on imaging in the setting of craniofacial trauma, skull base tumours, intracranial infection and after neurological intervention. Spontaneous pneumocephalus in the absence of these conditions is exceedingly rare, with only approximately 30 cases reported in the literature to date. Spontaneous otogenic pneumocephalus (SOP) is believed to occur as a result of anomalous communication between the intracranial space and a hyper-pneumatised temporal bone, with either positive extra-to-intracranial pressure or negative intracranial pressure gradient. These anomalous communicating channels may only become clinically apparent when triggered by episodes of acute increase in middle ear pressure during coughing, sneezing, Valsalva manoeuvre or significant change in atmospheric pressure. Patients may exhibit a wide range of neurological symptoms and the aim of treatment is to reduce the risk of complications such as infection and intracranial hypertension. Both conservative and neurosurgical approaches have been described. We report a case of SOP in which the patient was conservatively managed, and spontaneous resolution of pneumocephalus was documented on serial computed tomography (CT) scans. This unique case clearly demonstrates the natural history and temporal evolution of SOP without surgical intervention. This knowledge may potentially obviate the need for surgery, thus reducing morbidity and mortality in patients who are poor surgical candidates.