Diagnostic Yield, Safety, and Outcomes of Head-to-Pelvis Sudden Death CT Imaging in Post Arrest Care: The CT FIRST Cohort Study

AIM

Our aim was to test whether a head-to-pelvis CT scan improves diagnostic yield and speed to identify causes for out of hospital circulatory arrest (OHCA).

METHODS

CT FIRST was a prospective observational pre-/post-cohort study of patients successfully resuscitated from OHCA. Inclusion criteria included unknown cause for arrest, age>18 years, stability to undergo CT, and no known cardiomyopathy or obstructive coronary artery disease. A head-to-pelvis sudden death CT (SDCT) scan within 6 hours of hospital arrival was added to the standard of care for patients resuscitated from OHCA (post-cohort) and compared to standard of care (SOC) alone (pre-cohort). The primary outcome was SDCT diagnostic yield. Secondary outcomes included time to identifying OHCA cause and time-critical diagnoses, SDCT safety, and survival to hospital discharge.

RESULTS

Baseline characteristics between the SDCT (N=104) and the SOC (N=143) cohorts were similar. CT scans (either head, chest, and/or abdomen) were ordered in 74 (52%) of SOC patients. Adding SDCT scanning identified 92% of causes for arrest compared to 75% (SOC-cohort; p value <0.001) and reduced the time to diagnosis by 78% (SDCT 3.1 hours, SOC alone 14.1 hours, p <0.0001). Identification of critical diagnoses was similar between cohorts, but SDCT reduced delayed (>6 hours) identification of critical diagnoses by 81% (p<0.001). SDCT safety endpoints were similar including acute kidney injury. Patient survival to discharge was similar between cohorts.

DISCUSSION

SDCT scanning early after OHCA resuscitation safely improved the efficiency and diagnostic yield for causes of arrest compared to the standard of care alone.

CLINICAL TRIALS NUMBER

NCT03111043.

Impact of Follow-Up Imaging Recommendation Specificity on Adherence

Radiology reports often contain follow-up imaging recommendations, but failure to comply with them in a timely manner can lead to delayed treatment, poor patient outcomes, complications, and legal liability. Using a dataset containing 2,972,164 exams for over 7 years, in this study we explored the association between recommendation specificity on follow-up rates. Our results suggest that explicitly mentioning the follow-up interval as part of a follow-up imaging recommendation has a significant impact on adherence making these recommendations 3 times more likely (95% CI: 2.95 - 3.05) to be followed-up, while explicit mentioning of the follow-up modality did not have a significant impact. Our findings can be incorporated into routine dictation macros so that the follow-up duration is explicitly mentioned whenever clinically applicable, and/or used as the basis for a quality improvement project focussed on improving adherence to follow-up imaging recommendations.

Prevalence and Patterns of Resuscitation-Associated Injury Detected by Head-to-Pelvis Computed Tomography After Successful Out-of-Hospital Cardiac Arrest Resuscitation

Background Patients resuscitated from out-of-hospital circulatory arrest (OHCA) frequently have cardiopulmonary resuscitation injuries identifiable by computed tomography, although the prevalence, types of injury, and effects on clinical outcomes are poorly characterized. Methods and Results We assessed the prevalence of resuscitation-associated injuries in a prospective, observational study of a head-to-pelvis sudden-death computed tomography scan within 6 hours of successful OHCA resuscitation. Primary outcomes included total injuries and time-critical injuries (such as organ laceration). Exploratory outcomes were injury associations with mechanical cardiopulmonary resuscitation and survival to discharge. Among 104 patients with OHCA (age 56±15 years, 30% women), 58% had bystander cardiopulmonary resuscitation, and total cardiopulmonary resuscitation time was 15±11 minutes. The prevalence of resuscitation-associated injury was high (81%), including 15 patients (14%) with time-critical findings. Patients with resuscitation injury were older (58±15 versus 46±13 years; P<0.001), but had otherwise similar baseline characteristics and survival compared with those without. Mechanical chest compression systems (27%) had more frequent sternal fractures (36% versus 12%; P=0.009), including displaced fractures (18% versus 1%; P=0.005), but no difference in survival (46% versus 41%; P=0.66). Conclusions In patients resuscitated from OHCA, head-to-pelvis sudden-death computed tomography identified resuscitation injuries in most patients, with nearly 1 in 7 with time-critical complications, and one-half with extensive rib-cage injuries. These data suggest that sudden-death computed tomography may have additional diagnostic utility and treatment implications beyond evaluating causes of OHCA. These important findings need to also be taken in context of the certain fatal outcome without resuscitation efforts. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03111043.

Management of gastrointestinal bleeding: Society of Abdominal Radiology (SAR) Institutional Survey

Despite guidelines developed to standardize the diagnosis and management of gastrointestinal (GI) bleeding, significant variability remains in recommendations and practice. The purpose of this survey was to obtain information on practice patterns for the evaluation of overt lower GI bleeding (LGIB) and suspected small bowel bleeding. A 34-question electronic survey was sent to all Society of Abdominal Radiology (SAR) members. Responses were received from 52 unique institutions (40 from the United States). Only 26 (50%) utilize LGIB management guidelines. 32 (62%) use CT angiography (CTA) for initial evaluation in unstable patients. In stable patients with suspected LGIB, CTA is the preferred initial exam at 21 (40%) versus colonoscopy at 24 (46%) institutions. CTA use increases after hours for both unstable (n = 32 vs. 35, 62% vs. 67%) and stable patients (n = 21 vs. 27, 40% vs 52%). CTA is required before conventional angiography for stable (n = 36, 69%) and unstable (n = 15, 29%) patients. 38 (73%) institutions obtain two post-contrast phases for CTA. 49 (94%) institutions perform CT enterography (CTE) for occult small bowel bleeding with capsule endoscopy (n = 26, 50%) and CTE (n = 21, 40%) being the initial test performed. 35 (67%) institutions perform multiphase CTE for occult small bowel bleeding. In summary, stable and unstable patients with overt lower GI are frequently imaged with CTA, while CTE is frequently performed for suspected occult small bowel bleeding.

Gastrointestinal Bleeding at CT Angiography and CT Enterography: Imaging Atlas and Glossary of Terms

Gastrointestinal (GI) bleeding is a common potentially life-threatening medical condition frequently requiring multidisciplinary collaboration to reach the proper diagnosis and guide management. GI bleeding can be overt (eg, visible hemorrhage such as hematemesis, hematochezia, or melena) or occult (eg, positive fecal occult blood test or iron deficiency anemia). Upper GI bleeding, which originates proximal to the ligament of Treitz, is more common than lower GI bleeding, which arises distal to the ligament of Treitz. Small bowel bleeding accounts for 5-10% of GI bleeding cases commonly manifesting as obscure GI bleeding, where the source remains unknown after complete GI tract endoscopic and imaging evaluation. CT can aid in identifying the location and cause of bleeding and is an important complementary tool to endoscopy, nuclear medicine, and angiography in evaluating patients with GI bleeding. For radiologists, interpreting CT scans in patients with GI bleeding can be challenging owing to the large number of images and the diverse potential causes of bleeding. The purpose of this pictorial review by the Society of Abdominal Radiology GI Bleeding Disease-Focused Panel is to provide a practical resource for radiologists interpreting GI bleeding CT studies that reviews the proper GI bleeding terminology, the most common causes of GI bleeding, key patient history and risk factors, the optimal CT imaging technique, and guidelines for case interpretation and illustrates many common causes of GI bleeding. A CT reporting template is included to help generate radiology reports that can add value to patient care. An invited commentary by Al Hawary is available online. Online supplemental material is available for this article. ^©RSNA, 2021.

Environmental Factors Predictive of No-Show Visits in Radiology: Observations of Three Million Outpatient Imaging Visits Over 16 Years

PURPOSE

To evaluate the impact of environmental and socioeconomic factors on outpatient cancellations and "no-show visits" (NSVs) in radiology.

MATERIALS AND METHODS

We conducted a retrospective analysis by collecting environmental factor data related to outpatient radiology visits occurring between 2000 and 2015 at our multihospital academic institution. Appointment attendance records were joined with daily weather observations from the National Oceanic and Atmospheric Administration and estimated median income from the US Census American Community Survey. A multivariate logistic regression model was built to examine relationships between NSV rate and median income, commute distance, maximum daily temperature, and daily snowfall.

RESULTS

There were 270,574 (8.0%) cancellations and 87,407 (2.6%) NSVs among 3,379,947 scheduled outpatient radiology appointments and 575,206 unique patients from 2000 to 2015. Overall cancellation rates decreased from 14% to 8%, and NSV rates decreased from 6% to 1% as median income increased from $20,000 to $120,000 per year. In a multivariate model, the odds of NSV decreased 10.7% per $10,000 increase in median income (95% confidence interval [CI]: 10.3%-11.1%) and 2.0% per 10°F increase in maximum daily temperature (95% CI: 1.3%-1.6%). The odds of NSV increased 1.4% per 10-mile increase in commute distance (95% CI: 1.3%-1.6%) and 4.5% per 1-inch increase in daily snowfall (95% CI: 3.6%-5.3%). Commute distance was more strongly associated with NSV for those in the two lower tertiles of income than the highest tertile (P < .001).

CONCLUSION

Environmental factors are strongly associated with patients' attendance at scheduled outpatient radiology examinations. Modeling of appointment failure risk based on environmental features can help increase the attendance of outpatient radiology appointments.

Detecting Technical Image Quality in Radiology Reports

Image interpretation accuracy is critical to ensure optimal care, yet many diagnostic reports contain expressions of uncertainty often due to shortcomings in technical quality among other factors. While radiologists will usually attempt to interpret images and render a diagnosis even if the imaging quality is suboptimal, often the details related to any quality concerns are dictated into the report. Despite imaging exam quality being an import factor for accurate image interpretation, there is a significant knowledge gap in terms of understanding the nature and frequency of technical limitations mentioned in radiology reports. To address some of these limitations, in this research we developed algorithms to automatically detect a broad spectrum of acquisition-related quality concerns using a dataset containing 1,210,858 exams. There was some type of a quality concern mentioned in 2.4% of exams with motion being the most frequent.

CT Detectability of Small Low-Contrast Hypoattenuating Focal Lesions: Iterative Reconstructions versus Filtered Back Projection

Purpose To investigate performance in detectability of small (≤1 cm) low-contrast hypoattenuating focal lesions by using filtered back projection (FBP) and iterative reconstruction (IR) algorithms from two major CT vendors across a range of 11 radiation exposures. Materials and Methods A low-contrast detectability phantom consisting of 21 low-contrast hypoattenuating focal objects (seven sizes between 2.4 and 10.0 mm, three contrast levels) embedded into a liver-equivalent background was scanned at 11 radiation exposures (volume CT dose index range, 0.5-18.0 mGy; size-specific dose estimate [SSDE] range, 0.8-30.6 mGy) with four high-end CT platforms. Data sets were reconstructed by using FBP and varied strengths of image-based, model-based, and hybrid IRs. Sixteen observers evaluated all data sets for lesion detectability by using a two-alternative-forced-choice (2AFC) paradigm. Diagnostic performances were evaluated by calculating area under the receiver operating characteristic curve (AUC) and by performing noninferiority analyses. Results At benchmark exposure, FBP yielded a mean AUC of 0.79 ± 0.09 (standard deviation) across all platforms which, on average, was approximately 2% lower than that observed with the different IR algorithms, which showed an average AUC of 0.81 ± 0.09 (P = .12). Radiation decreases of 30%, 50%, and 80% resulted in similar declines of observer detectability with FBP (mean AUC decrease, -0.02 ± 0.05, -0.03 ± 0.05, and -0.05 ± 0.05, respectively) and all IR methods investigated (mean AUC decrease, -0.00 ± 0.05, -0.04 ± 0.05, and -0.04 ± 0.05, respectively). For each radiation level and CT platform, variance in performance across observers was greater than that across reconstruction algorithms (P = .03). Conclusion Iterative reconstruction algorithms have limited radiation optimization potential in detectability of small low-contrast hypoattenuating focal lesions. This task may be further complicated by a high degree of variation in radiologists' performances, seemingly exceeding real performance differences among reconstruction algorithms. © RSNA, 2018 Online supplemental material is available for this article.

Understanding Why Patients No-Show: Observations of 2.9 Million Outpatient Imaging Visits Over 16 Years

PURPOSE

To understand why patients "no-show" for imaging appointments, and to provide new insights for improving resource utilization.

MATERIALS AND METHODS

We conducted a retrospective analysis of nearly 2.9 million outpatient examinations in our radiology information system from 2000 to 2015 at our multihospital academic institution. No-show visits were identified by the "reason code" entry "NOSHOW" in our radiology information system. We restricted data to radiography, CT, mammography, MRI, ultrasound, and nuclear medicine examinations that included all studied variables. These variables included modality, patient age, appointment time, day of week, and scheduling lead time. Multivariate logistic regression was used to identify factors associated with no-show visits.

RESULTS

Out of 2,893,626 patient visits that met our inclusion criteria, there were 94,096 no-shows during the 16-year period. Rates of no-show visits varied from 3.36% in 2000 to 2.26% in 2015. The effect size for no-shows was strongest for modality and scheduling lead time. Mammography had the highest modality no-show visit rate of 6.99% (odds ratio [OR] 5.38, P < .001) compared with the lowest modality rate of 1.25% in radiography. Scheduling lead time greater than 6 months was associated with more no-show visits than scheduling within 1 week (OR 3.18, P < .001). Patients 60 years and older were less likely to miss imaging appointments than patients under 40 (OR 0.70, P < .001). Mondays and Saturdays had significantly higher rates of no-show than Sundays (OR 1.52 and 1.51, P < .001).

CONCLUSION

Modality type and scheduling lead time were the most predictive factors of no-show. This may be used to guide new interventions such as targeted reminders and flexible scheduling.

Improving Quality of Follow-Up Imaging Recommendations in Radiology

Failure of timely follow-up imaging recommendations can result in suboptimal patient care. Evidence suggests that the use of conditional language in follow-up recommendations is associated with changes to follow-up compliance. Assuming that referring physicians prefer explicit guidance for follow-up recommendations, we develop algorithms to extract recommended modality and interval from follow-up imaging recommendations related to lung, thyroid and adrenal findings. Using a production dataset of 417,451 radiology reports, we observed that on average, follow-up interval was not mentioned in 79.4% of reports, and modality was missing in 47.4% of reports (4,819 reports contained a follow-up imaging recommendation for one of the three findings). We also developed an interactive dashboard to be used to monitor compliance rates. Recognizing the importance of increasing precision of follow-up recommendations, a quality improvement pilot study is underway with the goal of achieving a target where follow-up modality and interval are both explicitly specified.

Pericardial rupture and cardiac herniation in blunt trauma

Pericardial rupture in blunt trauma is rarely seen on computed tomography (CT) imaging due to its high initial mortality. We report a case of a 53-year-old man who presented to the Emergency Department in hemodynamic shock after intentional fall from height. Chest radiograph, which was taken in the trauma bay as a part of his primary survey, showed abnormal mediastinum contour with pneumopericardium. Pericardial rupture with cardiac herniation, and tamponade secondary to pneumopericardium, was diagnosed on trauma CT scan. The patient underwent emergent surgical management with thoracotomy to reduce the herniation and repair the pericardium. Immediate suspicion for pericardial and cardiac injury on the initial chest radiograph and rapid diagnosis on CT was indispensable for this patient's favorable outcome.

Extracting Follow-Up Recommendations and Associated Anatomy from Radiology Reports

Adherence rates for timely imaging follow-up are usually low due to low rates of diligence by referring physicians and/or patients with following recommendations for follow-up imaging. This can lead to delayed treatment, poor patient outcomes, unnecessary testing, and legal liability. Existing follow-up recommendation detection methods are often disease- and modality-specific. To address some of these limitations, we present a generic radiology report processing pipeline that can be used to extract follow-up imaging recommendations by anatomy using an ontology-based approach. Using a large dataset from three hospitals, we discuss our methodology in the context of identifying follow-up imaging recommendations that are related to lung, adrenal and/or thyroid conditions. The algorithm has 99% accuracy (95% CI: 95.8-99%). We also present an interactive dashboard that can be used to understand trends related to follow-up recommendations.

Call for a new classification system and treatment strategy in blunt aortic injury

OBJECTIVE

The current Society for Vascular Surgery (SVS) classification scheme for blunt aortic injury (BAI) is descriptive but does not guide therapy. We propose a simplified classification scheme based on our robust experience with BAI that is descriptive and guides therapy.

METHODS

Patients presenting with BAI between January 1999 and September 2014 were identified from our institution's trauma registry. We divided patients into eras by time. Era 1: before the first United States Food and Drug Administration (FDA)-approved thoracic endovascular aortic repair (TEVAR) device (1999-2005); era 2: FDA-approved TEVAR devices (2005-2010); and era 3: FDA-approved BAI-specific devices (2010-present). Baseline demographic information, Injury Severity Score, hospital details, and survival were collected and compared. Our classification scheme was minimal aortic injury, SVS grade 1 and 2; moderate aortic injury, SVS grade 3; and severe aortic injury, SVS grade 4.

RESULTS

We identified 226 patients with a diagnosis of BAI: 75 patients in era 1, 84 in era 2, and 67 in era 3. Mean Injury Severity Score was 39.5 (range, 16-75). The BAI-related in-hospital mortality was significantly higher before endovascular introduction in era 1 (14.6% vs 4.8%; P = .03), but was not significantly different between eras 2 and 3 or before and after BAI-specific devices were introduced (P = .43). Of 146 patients (64.6%) who underwent aortic intervention, 91 underwent endovascular repair, and 55 underwent open repair. All but nine patients (94%) had a moderate or severe injury. Survival across all three eras of patients undergoing operative intervention was 80.2%. Survival in eras 2 and 3 was higher than in era 1 (86.4% vs 73.8%) but was not significant (P = .38). Of 47 patients in eras 2 and 3 with minimal aortic injury, 45 (96%) were managed nonoperatively, with no BAI-related deaths. After 2007, follow-up imaging was obtained in 38 patients (80%) with minimal aortic injury, and progression was not observed. Computed tomography scans showed the injury in 13 patients appeared stable, 19 had complete resolution (50%), and 6 had a decreasing size of injury.

CONCLUSIONS

Our experience confirms that BAI-related mortality for patients who survive to presentation is now 5%. From our findings during the past 15 years, we propose simplification of the SVS grading criteria of BAI into minimal, moderate, and severe based on treatment differences among the three groups. Minimal aortic injury can be successfully managed nonoperatively without mandatory follow-up imaging. Moderate aortic injury can be managed semielectively with TEVAR, and severe aortic injury, requires emergency TEVAR.

The effect of trauma backboards on computed tomography radiation dose

AIM

To assess the effect of trauma backboards on the radiation dose at computed tomography (CT) when using automatic tube current modulation (ATCM).

MATERIALS AND METHODS

An anthropomorphic phantom was scanned with two commercially available CT systems (GE LightSpeed16 Pro and Siemens Definition AS+) without and with backboards. Tube current-time product (mAs), and CTDIvol (mGy) were recorded for each examination. Thermoluminescent dosimeters were used to measure skin entrance dose in the pelvis and breast. Statistical significance was determined using a two-sample t-test. In addition, an institutional review board-approved retrospective image review was performed to quantify the frequency of backboard use during CT in the emergency department.

RESULTS

There was a statistically significant increase in maximum tube current-time product (p<0.05) and CTDIvol (p<0.05) with the presence of a backboard; tube current-time product increased up to 31% and CTDIvol increased up to 27%. There was a significant increase in skin entrance dose in the anterior and posterior pelvis (p<0.05) with the presence of a backboard; skin entrance dose increased up to 25% in the anterior pelvis. Skin entrance dose to the breast increased with a backboard, although this was not statistically significant. The frequency of backboard use during CT markedly decreased (from 77% to 3%) after instituting a multidisciplinary policy to promptly remove patients from backboards upon arrival to the emergency department after a primary clinical survey.

CONCLUSIONS

Using backboards during CT with ATCM can significantly increase the radiation dose. Although the decision to maintain patients on backboards is multifactorial, attempts should be made to minimise backboard use during CT when possible.

Comparative Effectiveness Research: Alternatives to "Traditional" Computed Tomography Use in the Acute Care Setting

Computed tomography (CT) scanning is an essential diagnostic tool and has revolutionized care of patients in the acute care setting. However, there is widespread agreement that overutilization of CT, where benefits do not exceed possible costs or harms, is occurring. The goal was to seek consensus in identifying and prioritizing research questions and themes that involve the comparative effectiveness of "traditional" CT use versus alternative diagnostic strategies in the acute care setting. A modified Delphi technique was used that included input from emergency physicians, emergency radiologists, medical physicists, and an industry expert to achieve this.

Incidence and Risk Factors for Postcontrast Acute Kidney Injury in Survivors of Sudden Cardiac Arrest

STUDY OBJECTIVE

Survivors of sudden cardiac arrest may be exposed to iodinated contrast from invasive coronary angiography or contrast-enhanced computed tomography, although the effects on incident acute kidney injury are unknown. The study objective was to determine whether contrast administration within the first 24 hours was associated with acute kidney injury in survivors of sudden cardiac arrest.

METHODS

This cohort study, derived from a prospective clinical trial, included patients with sudden cardiac arrest who survived for 48 hours, had no history of end-stage renal disease, and had at least 2 serum creatinine measurements during hospitalization. The contrast group included patients with exposure to iodinated contrast within 24 hours of sudden cardiac arrest. Incident acute kidney injury and first-time dialysis were compared between contrast and no contrast groups and then controlled for known acute kidney injury risk factors.

RESULTS

Of the 199 survivors of sudden cardiac arrest, 94 received iodinated contrast. Mean baseline serum creatinine level was 1.3 mg/dL (95% confidence interval [CI] 1.4 to 1.5 mg/dL) for the contrast group and 1.6 mg/dL (95% CI 1.4 to 1.7 mg/dL) for the no contrast group. Incident acute kidney injury was lower in the contrast group (12.8%) than the no contrast group (17.1%; difference 4.4%; 95% CI -9.2% to 17.5%). Contrast administration was not associated with significant increases in incident acute kidney injury within quartiles of baseline serum creatinine level or after controlling for age, sex, race, congestive heart failure, diabetes, and admission serum creatinine level by regression analysis. Older age was independently associated with acute kidney injury.

CONCLUSION

Despite elevated baseline serum creatinine level in most survivors of sudden cardiac arrest, iodinated contrast administration was not associated with incident acute kidney injury even when other acute kidney injury risk factors were controlled for. Thus, although acute kidney injury is not uncommon among survivors of sudden cardiac arrest, early (<24 hours) contrast administration from imaging procedures did not confer an increased risk for acute kidney injury.

Improving Outcomes in the Patient with Polytrauma: A Review of the Role of Whole-Body Computed Tomography

Whole-body computed tomography (WBCT) is used for the workup of the patient with blunt polytrauma. WBCT is associated with improved patient survival and reduces the emergency department length of stay. However, randomized studies are needed to determine whether early WBCT improves survival, to clarify which patients benefit the most, and to model the costs of this technique compared with traditional workup. Advancements in modern multidetector computed tomography technology and an improved understanding of optimal protocols have enabled one to scan the entire body and achieve adequate image quality for a comprehensive trauma assessment in a short period.

Impact of incremental increase in CT image noise on detection of low-contrast hypodense liver lesions

RATIONALE AND OBJECTIVES

To determine the impact of incremental increases in computed tomography (CT) image noise on detection of low-contrast hypodense liver lesions.

MATERIAL AND METHODS

We studied 50 CT examinations acquired at image noise index (NI) of 15 and hypodense liver lesions and 50 examinations with no lesions. Validation of a noise addition tool to be used in the evaluation of the CT examinations was performed with a liver phantom. Using this tool, three 100-image sets were assembled: an NI of 17.4 (simulating 75% of the original patient radiation dose), 21.2 (simulating 50% dose), and 29.7 (simulating 25%). Three readers scored certainty of lesion presence using a five-point Likert scale.

RESULTS

For original images (NI 15) plus images with NI of 17.4 and 21.2, sensitivity was >90% threshold (range, 95%-98%). For images with NI of 29.7, sensitivity was just below the threshold (89%). Reader Az values for receiver operating characteristic curves were good for original, NI 17.4, and NI 21.2 images (0.976, 0.973, and 0.96, respectively). For NI of 29.7, the Az decreased to 0.913. Detection sensitivity was <90% for both lesion size < 10 mm (85%) and lesion-to-liver contrast <60 Hounsfield units (85%) only at NI 29.7.

CONCLUSIONS

For low-contrast lesion detection in liver CT, image noise can be increased up to NI 21.2 (a 50% patient radiation dose reduction) without substantial reduction in sensitivity.

Coronary anomalies encountered in the acute setting: an imaging review

A broad spectrum of congenital coronary anomalies may be discovered on imaging and sometimes in the emergency setting on computed tomography (CT). Most coronary artery anomalies are of academic interest; however, a minority can cause morbidity and mortality and symptoms such as angina, myocardial infarction, or arrhythmias. These anomalies are usually discovered as an incidental finding on CT examinations as part of the diagnostic workup for other pathology or on dedicated coronary computed tomography angiography (CCTA) as part of the evaluation for a coronary cause of chest pain. The purpose of this pictorial review is to demonstrate the types of coronary anomalies and to enhance the clinicians' understanding of the imaging classifications and clinical implications.

Effect of an image-sharing network on CT utilization for transferred trauma patients: a 5-year experience at a level I trauma center

PURPOSE

The aim of this study was to evaluate the influence of an image-sharing network established between referring hospitals and a level I trauma center on CT utilization at the trauma center.

METHODS

This retrospective study was approved by the local institutional review board. The requirement for informed consent was waived. Harborview Medical Center's trauma registry was linked to billing department data, and detailed information on all resources utilized during each patient's hospitalization was obtained. Negative binomial regression was used to evaluate body region-specific CT utilization between direct-admit and transfer patients after adjustment for potential confounding variables. Special attention was paid to 2005 as the year internet-based image sharing between Harborview Medical Center and referring hospitals was established.

RESULTS

A total of 81,159 trauma patients were admitted to Harborview Medical Center (44% transfers) during the study period. The utilization of head CT slightly increased from 1996 to 2005, with no significant difference between direct-admit and transfer patients. Between 2005 and 2010, utilization remained relatively unchanged; however, significantly higher utilization rates were observed for direct-admit patients. A relatively similar pattern was observed for pelvic CT; however, between 2005 and 2010, CT use was greater for direct-admit compared with transfer patients. Abdominal and thoracic CT was relatively unchanged between 2005 and 2010. However, both studies had significantly higher utilization rates for direct-admit patients.

CONCLUSIONS

The utilization rates of CT of different body regions have been higher for direct-admit trauma patients compared with transfer patients since 2005; however, decreasing utilization trends have been observed in recent years.

Transfer patient imaging: current status, review of the literature, and the Harborview experience

Patients transferred for higher levels of care often arrive with medical imaging from the outside facility, with or without accompanying radiology reports. The handling of pretransfer studies by receiving radiologists introduces several concerns regarding resource utilization, medicolegal risk, and technical quality control. The authors review the current status of transfer patient imaging, with an emphasis on the role of the receiving emergency radiologist. Practice solutions developed at the authors' level I trauma center are described.

A text processing pipeline to extract recommendations from radiology reports

Communication of follow-up recommendations when abnormalities are identified on imaging studies is prone to error. The absence of an automated system to identify and track radiology recommendations is an important barrier to ensuring timely follow-up of patients especially with non-acute incidental findings on imaging examinations. In this paper, we present a text processing pipeline to automatically identify clinically important recommendation sentences in radiology reports. Our extraction pipeline is based on natural language processing (NLP) and supervised text classification methods. To develop and test the pipeline, we created a corpus of 800 radiology reports double annotated for recommendation sentences by a radiologist and an internist. We ran several experiments to measure the impact of different feature types and the data imbalance between positive and negative recommendation sentences. Our fully statistical approach achieved the best f-score 0.758 in identifying the critical recommendation sentences in radiology reports.

Automatic identification of critical follow-up recommendation sentences in radiology reports

Communication of follow-up recommendations when abnormalities are identified on imaging studies is prone to error. When recommendations are not systematically identified and promptly communicated to referrers, poor patient outcomes can result. Using information technology can improve communication and improve patient safety. In this paper, we describe a text processing approach that uses natural language processing (NLP) and supervised text classification methods to automatically identify critical recommendation sentences in radiology reports. To increase the classification performance we enhanced the simple unigram token representation approach with lexical, semantic, knowledge-base, and structural features. We tested different combinations of those features with the Maximum Entropy (MaxEnt) classification algorithm. Classifiers were trained and tested with a gold standard corpus annotated by a domain expert. We applied 5-fold cross validation and our best performing classifier achieved 95.60% precision, 79.82% recall, 87.0% F-score, and 99.59% classification accuracy in identifying the critical recommendation sentences in radiology reports.

The obese emergency patient: imaging challenges and solutions

The dramatic rise in the prevalence of obesity among children and adults in the United States over the last several decades has brought several new challenges to the delivery of healthcare. The increased utilization of and dependence on imaging for accurate and timely diagnosis has placed the radiology department in a unique position in the provision of care for the obese emergency patient. Radiology practices must be cognizant of the imaging challenges presented by the obese patient and adjust their imaging algorithms accordingly to optimize all types of diagnostic studies. The article systematically reviews common pitfalls and offers methods to improve image quality when using radiography, ultrasonography, and computed tomography to image the obese patient population.

Overnight resident interpretation of torso CT at a level 1 trauma center an analysis and review of the literature

RATIONALE AND OBJECTIVES

At the authors' level 1 trauma center, postgraduate year 3 and 4 radiology residents interpret urgent overnight imaging studies, which are reviewed by attending radiologists the next morning. The goals of this study were to determine the discrepancy rate for torso computed tomography between resident radiologists' preliminary interpretations and attending radiologists' final interpretations and to identify adverse patient events secondary to the delayed diagnoses.

MATERIALS AND METHODS

All torso computed tomographic studies interpreted by weekday night residents (8 pm to 8 am) from January 1, 2005, to March 13, 2007, were evaluated retrospectively. Major discrepancies between the residents' interpretations and the attending radiologists' interpretations were compiled. Exams with major discrepancies were additionally reviewed by two radiology residents and an attending emergency radiologist. The medical records of patients with major discrepant findings were also reviewed to identify adverse events that occurred because of the delays in final interpretation.

RESULTS

A total of 4768 chest, abdominal, and/or pelvic computed tomographic studies were interpreted during the study period. A total of 112 major discrepancies were collected. In 17 cases (15%), two additional radiology residents and an attending emergency radiologist agreed with the initial residents' interpretations, decreasing the major discrepancy rate to 95 of 4768 (2.0%), consistent with data from the literature (0.4%-10%). Management was changed in 16 patients (0.3%) because of the major discrepancies: 13 patients underwent additional investigations, and 3 patients were recalled to the emergency room. No mortality or morbidity was directly attributed to the delays in diagnosis.

CONCLUSION

At the authors' institution, there was a 2.0% discrepancy rate between residents' preliminary interpretations and attending radiologists' final interpretations of overnight torso computed tomography, with a small rate of additional intervention as a result of the major discrepancies. No adverse patient effects were directly attributable to discrepant interpretations. In discrepant cases, there was a 15% disagreement rate (17 of 112) between attending radiologists, suggesting some degree of interreader variance in interpretation. In addition, this disagreement rate among attending radiologists may imply that these cases were complex. Because there is educational value in overnight call, independent radiology resident coverage should continue.

An evaluation of multidetector computed tomography in detecting pancreatic injury: results of a multicenter AAST study

BACKGROUND

Efforts to determine the suitability of low-grade pancreatic injuries for nonoperative management have been hindered by the inaccuracy of older computed tomography (CT) technology for detecting pancreatic injury (PI). This retrospective, multicenter American Association for the Surgery of Trauma-sponsored trial examined the sensitivity of newer 16- and 64-multidetector CT (MDCT) for detecting PI, and sensitivity/specificity for the identification of pancreatic ductal injury (PDI).

METHODS

Patients who received a preoperative 16- or 64-MDCT followed by laparotomy with a documented PI were enrolled. Preoperative MDCT scans were classified as indicating the presence (+) or absence (-) of PI and PDI. Operative notes were reviewed and all patients were confirmed as PI (+), and then classified as PDI (+) or (-). As all patients had PI, an analysis of PI specificity was not possible. PI patients formed the pool for further PDI analysis. As sensitivity and specificity data were available for PDI, multivariate logistic regression was performed for PDI patients using the presence or absence of agreement between CT and operative note findings as an independent variable. Covariates were age, gender, Injury Severity Score, mechanism of injury, presence of oral contrast, presence of other abdominal injuries, performance of the scan as part of a dedicated pancreas protocol, and image thickness < or =3 mm or > or =5 mm.

RESULTS

Twenty centers enrolled 206 PI patients, including 71 PDI (+) patients. Intravenous contrast was used in 203 studies; 69 studies used presence of oral contrast. Eight-nine percent were blunt mechanisms, and 96% were able to have their duct status operatively classified as PDI (+) or (-). The sensitivity of 16-MDCT for all PI was 60.1%, whereas 64-MDCT was 47.2%. For PDI, the sensitivities of 16- and 64-MDCT were 54.0% and 52.4%, respectively, with specificities of 94.8% for 16-MDCT scanners and 90.3% for 64-MDCT scanners. Logistic regression showed that no covariates were associated with an increased likelihood of detecting PDI for either 16- or 64-MDCT scanners. The area under the curve was 0.66 for the 16-MDCT PDI analysis and 0.77 for the 64-MDCT PDI analysis.

CONCLUSION

Sixteen and 64-MDCT have low sensitivity for detecting PI and PDI, while exhibiting a high specificity for PDI. Their use as decision-making tools for the nonoperative management of PI are, therefore, limited.

Prospective, randomized trial of hypertonic sodium lactate versus lactated Ringer's solution for burn shock resuscitation

We prospectively randomized 51 adult burned patients on admission to study fluid, electrolyte, and physiologic parameters during burn resuscitation with the use of hypertonic saline (HSL, Na 250 mEq/L, 514 mOsm) or lactated Ringer's solution (LR, Na 130 mEq/L, 268 mOsm). Patients suffered at least 20% total body surface area burns (BSA); the mean BSA injury was 36.7% BSA, with a range of 20 to 74% BSA. All patients were admitted to our Burn Center within at least 12 hours of injury. Laboratory studies included frequent determinations of serum chemistries including osmolalities, and continuous 24-hour urine collections for electrolytes and osmolality determinations. Fluid requirements (cc/kg/% BSA), urine output (cc/kg/hr), sodium intake and excretion (mEq/kg/% BSA), serum and urine osmolality (mOsm/kg), serum creatinine (mg/dl), body weight (kg), and enteral intake (cc/24 hrs and calories/24 hrs) were analyzed for comparison at 24-hour intervals following burn injury. Using Student's t-test, significance was attributed to a p less than 0.05. Nonparametric methods were used to compare non-normalized data. Regression analysis was used to compare sodium intake (mEq/kg) and fluid intake (cc/kg) between the HSL and the LR groups in relation to % BSA. Our data show no advantage of HSL over conventional therapy with LR for burn resuscitation. We were not able to demonstrate decreased fluid requirements, improved tolerance of feedings, or decrease in per cent weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)