Assessment of Claimant, Clinical, and Financial Characteristics of Teleradiology Medical Malpractice Cases.

Background The increasing use of teleradiology has been accompanied by concerns relating to risk management and patient safety. Purpose To compare characteristics of teleradiology and nonteleradiology radiology malpractice cases and identify contributing factors underlying these cases. Materials and Methods In this retrospective analysis, a national database of medical malpractice cases was queried to identify cases involving telemedicine that closed between January 2010 and March 2022. Teleradiology malpractice cases were identified based on manual review of cases in which telemedicine was coded as one of the contributing factors. These cases were compared with nonteleradiology cases that closed during the same time period in which radiology had been determined to be the primary responsible clinical service. Claimant, clinical, and financial characteristics of the cases were recorded, and continuous or categorical data were compared using the Wilcoxon rank-sum test or Fisher exact test, respectively. Results This study included 135 teleradiology and 3474 radiology malpractices cases. The death of a patient occurred more frequently in teleradiology cases (48 of 135 [35.6%]) than in radiology cases (685 of 3474 [19.7%]; P < .001). Cerebrovascular disease was a more common final diagnosis in the teleradiology cases (13 of 135 [9.6%]) compared with the radiology cases (124 of 3474 [3.6%]; P = .002). Problems with communication among providers was a more frequent contributing factor in the teleradiology cases (35 of 135 [25.9%]) than in the radiology cases (439 of 3474 [12.6%]; P < .001). Teleradiology cases were more likely to close with indemnity payment (79 of 135 [58.5%]) than the radiology cases (1416 of 3474 [40.8%]; P < .001) and had a higher median indemnity payment than the radiology cases ($339 230 [IQR, $120 790-$731 615] vs $214 063 [IQR, $66 620-$585 424]; P = .01). Conclusion Compared with radiology cases, teleradiology cases had higher clinical and financial severity and were more likely to involve issues with communication. © RSNA, 2024 See also the editorial by Mezrich in this issue.

Prevalence of Pneumonia Among Patients Who Died with COVID-19 Infection in Ancestral Versus Omicron Variant Eras.

RATIONALE AND OBJECTIVES: The Omicron variant of COVID-19 is less severe than the ancestral strain, leading to the potential for deaths in patients infected with the virus but who die of other causes. This study evaluated the difference in rates of pneumonia among patients who died with SARS-CoV-2 infection in the ancestral vs Omicron eras. MATERIALS AND METHODS: We identified patients who died within 30days of a positive SARS-CoV-2 test, from March 2020 through December 2022; variants were assigned based on the prevalent variant in the US at that time. We also obtained a control group from patients who died within 30days of a negative SARS-CoV-2 test in January 2022. The first CT after the test was reviewed in a blinded fashion and assigned a category from the RSNA Consensus Reporting Guidelines. The primary outcome was the difference in rates of positive (typical or indeterminate) COVID-19 findings in the ancestral vs Omicron eras. RESULTS: A total of 598 patients died during the ancestral era and 400 during the Omicron era, and 347 decedents comprised the control group. The rate of positive COVID-19 findings was 67/81 (83%) in the ancestral era and 43/81 (53%) in the Omicron era (P < .001), an absolute difference of 30% (95% CI 16%-43%). The rate of positive findings in the control group was 23/76 (30%). CONCLUSION: During the Omicron era, 30% fewer SARS-CoV-2-associated deaths were associated with COVID-19 pneumonia and were caused either by nonpulmonary effects of the infection or were unrelated to the infection.

A Novel Multidisciplinary Team Activation for Patients with Severe Gastrointestinal Bleeding: Creation of the Code GI Bleed Protocol.

Patients with gastrointestinal (GI) bleeding present to the emergency department (ED) with a wide spectrum of illness severity. Among the most critically ill patients, comorbidities and other risk factors, such as liver disease and anticoagulation, can complicate their management. These patients are resource-intensive to stabilize and resuscitate, often requiring the continuous attention of multiple ED staff members along with rapid mobilization of specialty care. At a tertiary care hospital with the ability to provide definitive care for the most critically ill patients with GI bleeding, we introduced a multi-disciplinary team activation pathway to bring together specialists to immediately respond to the ED. We designed a Code GI Bleed pathway to expedite hemodynamic stabilization, diagnostics, source control, and timely disposition out of the ED to the intensive care unit or relevant procedural area of the hospital.

A survey of ASER members on artificial intelligence in emergency radiology: trends, perceptions, and expectations.

PURPOSE: There is a growing body of diagnostic performance studies for emergency radiology-related artificial intelligence/machine learning (AI/ML) tools; however, little is known about user preferences, concerns, experiences, expectations, and the degree of penetration of AI tools in emergency radiology. Our aim is to conduct a survey of the current trends, perceptions, and expectations regarding AI among American Society of Emergency Radiology (ASER) members. METHODS: An anonymous and voluntary online survey questionnaire was e-mailed to all ASER members, followed by two reminder e-mails. A descriptive analysis of the data was conducted, and results summarized. RESULTS: A total of 113 members responded (response rate 12%). The majority were attending radiologists (90%) with greater than 10 years' experience (80%) and from an academic practice (65%). Most (55%) reported use of commercial AI CAD tools in their practice. Workflow prioritization based on pathology detection, injury or disease severity grading and classification, quantitative visualization, and auto-population of structured reports were identified as high-value tasks. Respondents overwhelmingly indicated a need for explainable and verifiable tools (87%) and the need for transparency in the development process (80%). Most respondents did not feel that AI would reduce the need for emergency radiologists in the next two decades (72%) or diminish interest in fellowship programs (58%). Negative perceptions pertained to potential for automation bias (23%), over-diagnosis (16%), poor generalizability (15%), negative impact on training (11%), and impediments to workflow (10%). CONCLUSION: ASER member respondents are in general optimistic about the impact of AI in the practice of emergency radiology and its impact on the popularity of emergency radiology as a subspecialty. The majority expect to see transparent and explainable AI models with the radiologist as the decision-maker.

Dual Energy-Derived Metrics for Differentiating Adrenal Adenomas From Nonadenomas on Single-Phase Contrast-Enhanced CT.

BACKGROUND. Adrenal masses are often indeterminate on single-phase postcontrast CT. Dual-energy CT (DECT) with three-material decomposition algorithms may aid characterization. OBJECTIVE. The purpose of this study was to compare the diagnostic performance of metrics derived from portal venous phase DECT, including virtual noncontrast (VNC) attenuation, fat fraction, iodine density, and relative enhancement ratio, for characterizing adrenal masses. METHODS. This retrospective study included 128 patients (82 women, 46 men; mean age, 64.6 ± 12.7 [SD] years) who between January 2016 and December 2019 underwent portal venous phase abdominopelvic DECT that showed a total of 139 adrenal lesions with an available reference standard based on all imaging, clinical, and pathologic records (87 adenomas, 52 nonadenomas [48 metastases, two adrenal cortical carcinomas, one ganglioneuroma, one hematoma]). Two radiologists placed ROIs to determine the following characteristics of the masses: VNC attenuation, fat fraction, iodine density normalized to portal vein, and for masses with VNC greater than 10 HU, relative enhancement ratio (ratio of portal venous phase attenuation to VNC attenuation). Readers' mean measurements were used for ROC analyses, and clinically optimal thresholds were derived as thresholds yielding the highest sensitivity at 100% specificity. RESULTS. Adenomas and nonadenomas were significantly different (all p < .001) in VNC attenuation (mean ± SD, 18.5 ± 12.9 vs 34.1 ± 8.9 HU), fat fraction (mean ± SD, 24.3% ± 8.2% vs 14.2% ± 5.6%), normalized iodine density (mean ± SD, 0.34 ± 0.15 vs 0.17 ± 0.17), and relative enhancement ratio (mean ± SD, 186% ± 96% vs 58% ± 59%). AUCs for all metrics ranged from 0.81 through 0.91. The metric with highest sensitivity for adenoma at the clinically optimal threshold (i.e., 100% specificity) was fat fraction (threshold, ≥ 23.8%; sensitivity, 59% [95% CI, 48-69%]) followed by VNC attenuation (≤ 15.2 HU; sensitivity, 39% [95% CI, 29-50%]), relative enhancement ratio (≥ 214%; sensitivity, 37% [95% CI, 25-50%]), and normalized iodine density (≥ 0.90; sensitivity, 1% (95% CI, 0-60%]). VNC attenuation at the traditional true noncontrast attenuation threshold of 10 HU or lower had sensitivity of 28% (95% CI, 19-38%) and 100% specificity. Presence of fat fraction 23.8% or greater or relative enhancement ratio 214% or greater yielded sensitivity of 68% (95% CI, 57-77%) with 100% specificity. CONCLUSION. For adrenal lesions evaluated with single-phase DECT, fat fraction had higher sensitivity than VNC attenuation at both the clinically optimal threshold and the traditional threshold of 10 HU or lower. CLINICAL IMPACT. By helping to definitively diagnose adenomas, DECT-derived metrics can help avoid downstream imaging for incidental adrenal lesions.

An Orchestration Platform that Puts Radiologists in the Driver's Seat of AI Innovation: a Methodological Approach.

Current AI-driven research in radiology requires resources and expertise that are often inaccessible to small and resource-limited labs. The clinicians who are able to participate in AI research are frequently well-funded, well-staffed, and either have significant experience with AI and computing, or have access to colleagues or facilities that do. Current imaging data is clinician-oriented and is not easily amenable to machine learning initiatives, resulting in inefficient, time consuming, and costly efforts that rely upon a crew of data engineers and machine learning scientists, and all too often preclude radiologists from driving AI research and innovation. We present the system and methodology we have developed to address infrastructure and platform needs, while reducing the staffing and resource barriers to entry. We emphasize a data-first and modular approach that streamlines the AI development and deployment process while providing efficient and familiar interfaces for radiologists, such that they can be the drivers of new AI innovations.

Psoas attenuation and cross-sectional area improve performance of traditional sarcopenia measurements in predicting one-year mortality among elderly patients undergoing emergency abdominal surgery: a pilot study of five computed tomography techniques.

BACKGROUND: Risk stratification is challenging in the growing population of geriatric patients requiring emergency surgery. Sarcopenia, which assesses muscle bulk, is a surrogate for frailty and predicts 1-year mortality, but does not incorporate potentially valuable additional information about muscle quality. OBJECTIVE: To describe five different CT methods of measuring sarcopenia and muscle quality and to determine which method has the greatest sensitivity for predicting 1-year mortality following emergency abdominal surgery in elderly patients. METHODS: This retrospective study includes 297 patients 70 years and older who underwent "urgent" or "emergent" laparotomy or laparoscopy for acute abdominal disease between 2006 and 2011 at a single quaternary academic medical center. All patients received a CT abdomen and pelvis with intravenous contrast within 1 month of surgery. Five different methods were applied to the psoas muscles on CT: method 1 (total psoas index TPI, which is total psoas area TPA normalized by height), method 2 ("pseudoarea" = anterior-posterior × transverse dimensions), method 3 (average HU), method 4 (TPA × HU), and method 5 ("pseudoarea" × HU). RESULTS: For all five CT measures, mortality was greatest for the lowest quartile by univariate and adjusted Cox proportional hazard analyses at all time points up to 1-year. The C-statistic was highest for Method 4, using a composite index of TPA and Hounsfield Units, indicating the greatest predictive ability to estimate mortality at all time points. CONCLUSION: Muscle quality and muscle size can be used in tandem to refine risk assessment of older patients undergoing emergency abdominal surgery. Routine calculation of the composite score of psoas cross-sectional area and HU in the emergency room setting may provide surgeons and patients valuable insight on the risk of 1-year mortality to guide preoperative decision-making and counseling. CLINICAL IMPACT: Muscle quality and size, both strong independent predictors of surgical outcomes in older patients undergoing emergency abdominal surgery, may be used in tandem to refine risk assessment. A composite score of psoas muscle cross-sectional area and Hounsfield units on CT may provide insight on 1-year mortality in this patient population.

Starting an Emergency Radiology Division: Scheduling and Staffing, Compensation, and Equity and Parity.

Establishing an emergency radiology division in a practice that has long-standing patterns of operational routines comes with both challenges and opportunities. In this article, considerations around scheduling and staffing, compensation, and equity and parity are provided with supporting literature references. Furthermore, a panel of experts having established, grown and managed emergency radiology divisions in North America and Europe share their experiences through a question and answer format.

Clinical applications of dual-energy computed tomography in neuroradiology.

Dual-energy computed tomography (DECT) has developed into a robust set of techniques with increasingly validated clinical applications in neuroradiology. We review some of the most common applications in neuroimaging along with demonstrative case examples that showcase the use of this technology in intracranial hemorrhage, stroke imaging, trauma imaging, artifact reduction, and tumor characterization.

Automated CT reformations reduce time and variability in trauma panscan exam completion.

PURPOSE: To test the hypothesis that an automated post-processing workflow reduces trauma panscan exam completion times and variability. METHODS: One-hundred-fifty consecutive trauma panscans performed between June 2018 and December 2019 were included, half before and half after implementation of an automated software-driven post-processing workflow. Acquisition and reconstruction timestamps were used to calculate total examination time (first acquisition to last reformation), setup time (between the non-contrast and contrast-enhanced acquisitions), and reconstruction time (for the contrast-enhanced reconstructions and reformations). The performing technologist was recorded and accounted for in analyses using linear mixed models to assess differences between the pre- and post-intervention groups. RESULTS: Exam, setup, and recon times were (mean ± standard deviation) 33.5 ± 4.6, 9.2 ± 2.4, and 23.6 ± 4.7 min before and 27.8 ± 1.5, 8.9 ± 1.4, and 18.9 ± 1.7 min after intervention. These reductions of 5.7 and 4.7 min in the mean exam and recon times were statistically significant (p < 0.001) while the setup time was not (p = 0.49). The reductions in standard deviation were statistically significant for exam and recon times (p < 0.0001) but not for setup time (p = 0.13). All automated panscans were completed within 36 min, versus 65% with the traditional workflow. CONCLUSION: Automation of image reconstruction workflow significantly decreased mean exam and reconstruction times as well as variability between exams, thus facilitating a consistently rapid imaging assessment, and potentially reducing delays in critical management decisions.

Advantages of Colour-Coded Dual-Energy CT Venography in Emergency Neuroimaging.

The objective of this Pictorial Review is to describe the use of colour-coded Dual-Energy CT (DECT) to aid in the interpretation of CT Venography (CTV) of the head for emergent indications. We describe a DE CTV acquisition and post-processing technique that can be readily incorporated into clinical workflow. Colour-coded DE CTV may aid the identification and characterization of dural venous sinus abnormalities and other cerebrovascular pathologies, which can improve diagnostic confidence in emergent imaging settings.

Prevalence of imaging findings of acute pancreatitis in emergency department patients with elevated serum lipase.

PURPOSE: To assess the association of imaging features of acute pancreatitis (AP) with the magnitude of lipase elevation in Emergency Department (ED) patients. METHODS: This Institutional Review Board-approved retrospective study included 509 consecutive patients presenting from 9/1/13-8/31/15 to a large academic ED with serum lipase levels ≥3× the upper limit of normal (ULN) (≥180 U/L). Patients were excluded if they did not have imaging (n = 131) or had a history of trauma, abdominal metastases, altered mental status, or transfer from an outside hospital (n = 190); the final study population was 188 patients. Imaging exams were retrospectively evaluated, and a consensus opinion of two subspecialty-trained abdominal radiologists was used to diagnose AP. Primary outcome was presence of imaging features of AP stratified by lipase level (≥3×-10× ULN and > 10× ULN). Secondary outcome was rate of discordant consensus evaluation compared to original radiologist's report. RESULTS: 25.0% of patients (47/188) had imaging features of AP. When lipase was >10× ULN (n = 94), patients were more likely to have imaging features of AP (34%) vs. those with mild elevation (16%) (p = 0.0042). There was moderately strong correlation between lipase level and presence of imaging features of AP (r = 0.48, p < 0.0001). Consensus review of CT and MRI images was discordant with the original report in 14.9% (28/188) of cases. CONCLUSION: Prevalence of imaging signs of AP in an ED population with lipase ≥3× ULN undergoing imaging is low. However, the probability of imaging features of AP increases as lipase value increases.

Radiation concerns in frequent flyer patients: should imaging history influence decisions about recurrent imaging?

Radiation risks from diagnostic imaging have captured the attention of patients and medical practitioners alike, yet it remains unclear how these considerations can best be incorporated into clinical decision-making. This manuscript presents a framework to consider these issues in a potentially at-risk population, the so called "frequent flyer" patients undergoing a large amount of recurrent imaging over time. Radiation risks from the low-dose exposures of diagnostic imaging are briefly reviewed, as applied to recurrent exposures. Some scenarios are then explored in which it may be helpful to incorporate knowledge of a patient's imaging history. There is no simple or uniformly applicable approach to these challenging and often nuanced clinical decisions. The complexity and variability of the underlying disease states and trajectories argues against alerting mechanisms based on a simple cumulative dose threshold. Awareness of imaging history may instead be beneficial in encouraging physicians and patients to take the long view, and to identify those populations of frequent flyers that might benefit from alternative imaging strategies.

Dual energy CT in clinical routine: how it works and how it adds value.

Dual energy computed tomography (DECT), also known as spectral CT, refers to advanced CT technology that separately acquires high and low energy X-ray data to enable material characterization applications for substances that exhibit different energy-dependent x-ray absorption behavior. DECT supports a variety of post-processing applications that add value in routine clinical CT imaging, including material selective and virtual non-contrast images using two- and three-material decomposition algorithms, virtual monoenergetic imaging, and other material characterization techniques. Following a review of acquisition and post-processing techniques, we present a case-based approach to highlight the added value of DECT in common clinical scenarios. These scenarios include improved lesion detection, improved lesion characterization, improved ease of interpretation, improved prognostication, inherently more robust imaging protocols to account for unexpected pathology or suboptimal contrast opacification, length of stay reduction, reduced utilization by avoiding unnecessary follow-up examinations, and radiation dose reduction. A brief discussion of post-processing workflow approaches, challenges, and solutions is also included.

Radiologist Reporting and Operational Management for Patients With Suspected COVID-19.

PURPOSE: The aim of this study was to evaluate the adoption and outcomes of locally designed reporting guidelines for patients with possible coronavirus disease 2019 (COVID-19). METHODS: A departmental guideline was developed for radiologists that specified reporting terminology and required communication for patients with imaging findings suggestive of COVID-19, on the basis of patient test status and imaging indication. In this retrospective study, radiology reports completed from March 1, 2020, to May 3, 2020, that mentioned COVID-19 were reviewed. Reports were divided into patients with known COVID-19, patients with "suspected" COVID-19 (having an order indication of respiratory or infectious signs or symptoms), and "unsuspected patients" (other order indications, eg, trauma or non-chest pain). The primary outcome was the percentage of COVID-19 reports using recommended terminology; the secondary outcome was percentages of suspected and unsuspected patients diagnosed with COVID-19. Relationships between categorical variables were assessed using the Fisher exact test. RESULTS: Among 77,400 total reports, 1,083 suggested COVID-19 on the basis of imaging findings; 774 of COVID-19 reports (71%) used recommended terminology. Of 574 patients without known COVID-19 at the time of interpretation, 345 (60%) were eventually diagnosed with COVID-19, including 61% (315 of 516) of suspected and 52% (30 of 58) of unsuspected patients. Nearly all unsuspected patients (46 of 58) were identified on CT. CONCLUSIONS: Radiologists rapidly adopted recommended reporting terminology for patients with suspected COVID-19. The majority of patients for whom radiologists raised concern for COVID-19 were subsequently diagnosed with the disease, including the majority of clinically unsuspected patients. Using unambiguous terminology and timely notification about previously unsuspected patients will become increasingly critical to facilitate COVID-19 testing and contact tracing as states begin to lift restrictions.

Bone Marrow Edema at Dual-Energy CT: A Game Changer in the Emergency Department.

Dual-energy CT is increasingly being used in the emergency department to help diagnose acute conditions. Its applications include demonstrating bone marrow edema (BME) seen in the setting of occult fractures and other acute conditions. Dual-energy CT acquires data with two different x-ray energy spectra and is able to help differentiate materials on the basis of their differential energy-dependent x-ray absorption behaviors. Virtual noncalcium (VNCa) techniques can be used to suppress the high attenuation of trabecular bone, thus enabling visualization of subtle changes in the underlying attenuation of the bone marrow. Visualization of BME can be used to identify occult or mildly displaced fractures, pathologic fractures, metastases, and some less commonly visualized conditions such as ligamentous injuries or inflammatory arthritis. The authors' major focus is use of dual-energy CT as a diagnostic modality in the setting of trauma and to depict subtle or occult fractures. The authors also provide some scenarios in which dual-energy CT is used to help diagnose other acute conditions. The causes and pathophysiology of BME are reviewed. Dual-energy CT image acquisition and VNCa postprocessing techniques are also discussed, along with their applications in emergency settings. The authors present potential pitfalls and limitations of these techniques and their possible solutions.©RSNA, 2020.

Dual-energy CT for routine imaging of the abdomen and pelvis: radiation dose and image quality.

PURPOSE: To assess the radiation dose and image quality of routine dual energy CT (DECT) of the abdomen and pelvis performed in the emergency department setting, compared with single energy CT (SECT). MATERIALS AND METHODS: Seventy-five consecutive routine contrast-enhanced SECT scans of the abdomen and pelvis meeting inclusion criteria were compared with 75 routine contrast-enhanced DECT scans matched by size and patient weight (within 10 lbs), performed on the same dual-source DECT scanner. Cohorts were compared in terms of radiation dose metrics of CT dose index (CTDIvol) and dose length product (DLP), objective measurements of image quality (signal, noise, and signal-to-noise ratio of a variety of anatomical landmarks), and subjective measurements of image quality scored by two emergency radiologists. RESULTS: Demographics and patient size were not statistically different between DECT and SECT cohorts. Both average scans CTDIvol and DLP were significantly lower with DECT than with SECT. Average scan CTDIvol for SECT was 14.7 mGy (± 6.6) and for DECT was 10.9 mGy (± 3.8) (p < 0.0001). Average scan DLP for SECT was 681.5 mGy cm (± 339.3) and for DECT was 534.8 mGy cm (± 201.9) (p < 0.0001). For objective image quality metrics, for all structures measured, noise was significantly lower and SNR was significantly higher with DECT compared with SECT. For subjective image quality, for both readers, there was no significant difference between SECT and DECT in subjective image quality for soft tissues and vascular structures, or for subjective image noise. CONCLUSIONS: DECT was performed with decreased radiation dose when compared with SECT, demonstrated improved objective measurements of image quality, and equivalent subjective image quality.

Dual-Energy CT to Differentiate Small Foci of Intracranial Hemorrhage from Calcium.

Background Diagnostic uncertainty in CT of possible intracranial hemorrhage requires short-interval follow-up imaging, resulting in reduced efficiency of care and higher costs. Purpose To quantify the diagnostic performance of dual-energy CT versus simulated single-energy CT in the differentiation of small foci of intracranial hemorrhage from calcium. Materials and Methods Images from consecutive unenhanced dual-energy CT of the head in patients from a single emergency department obtained from December 2014 to April 2016 were reviewed retrospectively for hyperattenuating intracranial foci. Ground truth was established from reference standard comparison CT or MRI. Foci were divided into development and test sets. Development set foci regions of interest were used to derive candidate CT attenuation thresholds for virtual noncalcium (VNCa) and calcium images. Test set foci were used for threshold validation, and diagnostic performance and confidence were evaluated for two readers blinded to final diagnosis. Statistical comparisons were made with exact binomial tests or repeated-measures analysis of variance. Results The study included 137 patients (65 years ± 17; 70 men) with 146 foci. Foci were divided into a development set (n = 105) and a test set (n = 41). Quantitative analysis of the development set produced candidate thresholds of 44 HU for VNCa images and 7 HU for calcium-only images, yielding diagnostic accuracies for the test set of 88% (36 of 41 foci; 95% confidence interval [CI]: 78%, 98%) and 95% (39 of 41 foci; 95% CI: 88%, 100%), respectively. Dual-energy CT improved reader accuracy from 90% (reader 1, 37 of 41 foci; 95% CI: 81%, 99%) and 93% (reader 2, 38 of 41 foci; 95% CI: 85%, 100%) to 100% (both readers, 41 of 41 foci; 95% CI: 100%, 100%). Diagnostic confidence (classifications rated as "certain") increased from 71% (29 of 41 foci; 95% CI: 57%, 85%) to 90% (37 of 41 foci; 95% CI: 81%, 99%) for reader 1 (P = .019) and from 46% (19 of 41 foci; 95% CI: 31%, 62%) to 85% (35 of 41 foci; 95% CI: 75%, 96%) for reader 2 (P = .0001). Conclusion Dual-energy CT showed high diagnostic performance in the differentiation of small foci of intracranial hemorrhage from calcium and improved diagnostic accuracy and confidence in the initial evaluation of suspected hemorrhage. © RSNA, 2019 See also the editorial by Kotsenas in this issue.

Image reconstruction for interrupted-beam x-ray CT on diagnostic clinical scanners.

Low-dose x-ray CT is a major research area with high clinical impact. Compressed sensing using view-based sparse sampling and sparsity-promoting regularization has shown promise in simulations, but these methods can be difficult to implement on diagnostic clinical CT scanners since the x-ray beam cannot be switched on and off rapidly enough. An alternative to view-based sparse sampling is interrupted-beam sparse sampling. SparseCT is a recently-proposed interrupted-beam scheme that achieves sparse sampling by blocking a portion of the beam using a multislit collimator (MSC). The use of an MSC necessitates a number of modifications to the standard compressed sensing reconstruction pipeline. In particular, we find that SparseCT reconstruction is feasible within a model-based image reconstruction framework that incorporates data fidelity weighting to consider penumbra effects and source jittering to consider the effect of partial source obstruction. Here, we present these modifications and demonstrate their application in simulations and real-world prototype scans. In simulations compared to conventional low-dose acquisitions, SparseCT is able to achieve smaller normalized root-mean square differences and higher structural similarity measures on two reduction factors. In prototype experiments, we successfully apply our reconstruction modifications and maintain image resolution at quarter-dose reduction level. The SparseCT design requires only small hardware modifications to current diagnostic clinical scanners, opening up new possibilities for CT dose reduction.

Correction to: Spectrum of diagnostic errors in cervical spine trauma imaging and their clinical significance.

The published version of this article unfortunately contained a mistake. Author given and family name Alessandrino Francesco was incorrectly interchanged. The correct presentation is given above. The original article has been corrected.