The appropriate use of CT: quality improvement and clinical decision-making in pediatric emergency medicine

Two-dimensional shear wave elastography can improve the diagnostic accuracy of ultrasonography in acute appendicitis

AIM

We aimed to evaluate the effectiveness of combining 2-dimensional shear wave elastography (2D-SWE) with ultrasonography (US) in diagnosing acute appendicitis in patients with suspected acute appendicitis.

METHODS

Clinical and laboratory findings, gray-scale US and 2D-SWE imaging features, operation information, and pathology results of 48 patients diagnosed with acute appendicitis who presented with right lower quadrant pain were prospectively evaluated. We compared the findings to the US and SWE imaging features of 79 asymptomatic patients.

RESULTS

Mean Alvarado score and appendix diameter were statistically significantly higher for acute appendicitis (p < 0.001). In patients with acute appendicitis, mesenteric lymphadenopathy and fat stranding were also more frequent (p < 0.001). The mean velocity and kPa values for appendix and mesenteric fat were statistically significantly higher in acute appendicitis (p < 0.001).

CONCLUSION

In the diagnosis of acute appendicitis, 2D-SWE increases the diagnostic performance of gray-scale US in the differentiation of inflamed and normal appendixes.

Recent Imaging Advancements for Lung Metastases in Children with Sarcoma

In children and adolescents affected by musculoskeletal sarcomas (both soft tissue and bone sarcomas), the presence of lung metastases is a frequent complication, that should be known since the patient's prognosis, as management, and treatment depend on it. During the staging phase, the detection of lung metastases should be sensitive and specific, and it should be carried out by minimizing the radiation exposure. To deal with this problem, imaging has reached important goals in recent years, thanks to the development of cone-beam CT or low-dose computed tomography, with some new iterative reconstruction methods, such as Veo and ASIR. Imaging is also fundamental for the possibility to perform lung biopsies under CT guidance, with less morbidity, less time-consumption, and shorter recovery time, compared to surgical biopsies.Moreover, important results have also been demonstrated in the treatment of lung metastases, due to the improvement of new mini-invasive image-guided percutaneous thermal ablation procedures, which proved to be safe and effective also in young patients.

Radiologic Assessment of Osteosarcoma Lung Metastases: State of the Art and Recent Advances

The lung is the most frequent site of osteosarcoma (OS) metastases, which are a critical point in defining a patient’s prognosis. Chest computed tomography (CT) represents the gold standard for the detection of lung metastases even if its sensitivity widely ranges in the literature since lung localizations are often atypical. ESMO guidelines represent one of the major references for the follow-up program of OS patients. The development of new reconstruction techniques, such as the iterative method and the deep learning-based image reconstruction (DLIR), has led to a significant reduction of the radiation dose with the low-dose CT. The improvement of these techniques has great importance considering the young-onset of the disease and the strict chest surveillance during follow-up programs. The use of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT is still controversial, while volume doubling time (VDT) and computer-aided diagnosis (CAD) systems are recent diagnostic tools that could support radiologists for lung nodules evaluation. Their use, well-established for other malignancies, needs to be further evaluated, focusing on OS patients.

Are Continued Efforts to Reduce Radiation Exposures from X-Rays Warranted?

There are pressures to avoid use of radiological imaging throughout all healthcare due to the notion that all radiation is carcinogenic. This perception stems from the long-standing use of the linear no-threshold (LNT) assumption of risk associated with radiation exposures. This societal perception has led to relentless efforts to avoid and reduce radiation exposures to patients at great costs. Many radiation reduction campaigns have been launched to dissuade doctors from using radiation imaging. Lower-dose imaging techniques and practices are being advocated. Alternate imaging procedures are encouraged. Are these efforts warranted? Based on recent evidence, LNT ideology is shown to be defunct for risk assessment at low-dose exposure ranges which includes X-rays and CT scans. In fact, the best evidence that was once used to support LNT ideology, including the Life Span Study data, now indicates thresholds for cancer induction are high; therefore, low-dose X-rays cannot cause harm. Current practices are safe as exposures currently encountered are orders of magnitude below threshold levels shown to be harmful. As long as imaging is medically warranted, it is shown that efforts to reduce exposures that are within background radiation levels and that are also shown to enhance health by upregulating natural adaptive protection systems are definitively wasted resources.

Review, monitor, educate: A quality improvement initiative for sustained chest radiation reduction in pediatric trauma patients

BACKGROUND

We hypothesize that in pediatric trauma patients, CT scans after normal chest x-rays do not add information that alters clinical decision making.

METHODS

A retrospective review of trauma patients < 15 years with chest imaging evaluated at a pediatric trauma center between 1/2013 and 6/2019 was performed. Imaging was reviewed for significant findings that could affect care. A guideline was established in January 2017 which emphasized x-rays prior to CTs and no CTs after normal x-rays. A prospective review was performed from 1/2017-6/2019. Pre and post guideline groups were compared.

RESULTS

From 2013 to 2016, 246 patients met inclusion. 29.5% had a chest CT after a normal x-ray, only 1.8% (1/57) had a significant result. From 2017 to 2019, 188 patients were reviewed post guideline; only 9.4% received a CT after normal x-ray, of which 6.3% (1/16) were significant. Neither changed clinical management.

CONCLUSIONS

Chest CT following normal chest x-ray does not change clinical management in pediatric trauma patients. Monitoring and education following guideline implementation improves long term outcomes.

Is spinal computed tomography necessary in pediatric trauma patients?

BACKGROUND

To investigate the prevalence of findings of spinal injury on computed tomography (CT) images of pediatric trauma patients and to define indicators for the possible presence of spinal injuries.

METHODS

Spinal CT for pediatric trauma patients (age ≤ 12 years) over a 2-year period was retrospectively evaluated for the presence of findings suggestive of spinal injury.

RESULTS

Of the 773 patients reviewed, 19 (2.4%) showed traumatic spinal lesions on their spinal CT images. These patients were significantly older than those without spinal lesions (mean age 7.9 ± 3.3 years vs 6.1 ± 3.3 years; P = 0.02). The prevalence of spinal trauma was significantly lower in patients aged 0-8 years than in those aged 9-12 years (P = 0.025). Spinal injury was significantly higher in female patients (P = 0.014). Most of the spinal injuries were located at the lumbar and sacral vertebral levels, and most did not cause neurological complications or require surgical treatment. Important indicators of the possible presence of spinal injuries were pain, tenderness, or ecchymosis over the spine, a low Glasgow Coma Scale score (≤12), head injury (for cervical injuries), or intrathoracic injuries and pelvic fractures (for lumbar and sacral injuries).

CONCLUSIONS

Most spinal CT examinations for the diagnosis of spinal injuries in children did not show positive findings. Thus, many children were exposed to an unnecessary high dose of radiation. New clinical evaluation criteria and indicators should be defined to diagnose spinal injuries and avoid unnecessary radiological examinations.

Use of natural language processing to improve predictive models for imaging utilization in children presenting to the emergency department

OBJECTIVE

To examine the association between the medical imaging utilization and information related to patients' socioeconomic, demographic and clinical factors during the patients' ED visits; and to develop predictive models using these associated factors including natural language elements to predict the medical imaging utilization at pediatric ED.

METHODS

Pediatric patients' data from the 2012-2016 United States National Hospital Ambulatory Medical Care Survey was included to build the models to predict the use of imaging in children presenting to the ED. Multivariable logistic regression models were built with structured variables such as temperature, heart rate, age, and unstructured variables such as reason for visit, free text nursing notes and combined data available at triage. NLP techniques were used to extract information from the unstructured data.

RESULTS

Of the 27,665 pediatric ED visits included in the study, 8394 (30.3%) received medical imaging in the ED, including 6922 (25.0%) who had an X-ray and 1367 (4.9%) who had a computed tomography (CT) scan. In the predictive model including only structured variables, the c-statistic was 0.71 (95% CI: 0.70-0.71) for any imaging use, 0.69 (95% CI: 0.68-0.70) for X-ray, and 0.77 (95% CI: 0.76-0.78) for CT. Models including only unstructured information had c-statistics of 0.81 (95% CI: 0.81-0.82) for any imaging use, 0.82 (95% CI: 0.82-0.83) for X-ray, and 0.85 (95% CI: 0.83-0.86) for CT scans. When both structured variables and free text variables were included, the c-statistics reached 0.82 (95% CI: 0.82-0.83) for any imaging use, 0.83 (95% CI: 0.83-0.84) for X-ray, and 0.87 (95% CI: 0.86-0.88) for CT.

CONCLUSIONS

Both CT and X-rays are commonly used in the pediatric ED with one third of the visits receiving at least one. Patients' socioeconomic, demographic and clinical factors presented at ED triage period were associated with the medical imaging utilization. Predictive models combining structured and unstructured variables available at triage performed better than models using structured or unstructured variables alone, suggesting the potential for use of NLP in determining resource utilization.

The evolution of image reconstruction for CT-from filtered back projection to artificial intelligence

Abstract

The first CT scanners in the early 1970s already used iterative reconstruction algorithms; however, lack of computational power prevented their clinical use. In fact, it took until 2009 for the first iterative reconstruction algorithms to come commercially available and replace conventional filtered back projection. Since then, this technique has caused a true hype in the field of radiology. Within a few years, all major CT vendors introduced iterative reconstruction algorithms for clinical routine, which evolved rapidly into increasingly advanced reconstruction algorithms. The complexity of algorithms ranges from hybrid-, model-based to fully iterative algorithms. As a result, the number of scientific publications on this topic has skyrocketed over the last decade. But what exactly has this technology brought us so far? And what can we expect from future hardware as well as software developments, such as photon-counting CT and artificial intelligence? This paper will try answer those questions by taking a concise look at the overall evolution of CT image reconstruction and its clinical implementations. Subsequently, we will give a prospect towards future developments in this domain.

Key Points

• Advanced CT reconstruction methods are indispensable in the current clinical setting.

• IR is essential for photon-counting CT, phase-contrast CT, and dark-field CT.

• Artificial intelligence will potentially further increase the performance of reconstruction methods.

Predictors of Positive CT Yield in Pediatric Patients With Nontraumatic Abdominal Pain

OBJECTIVE

The use of abdominal computed tomography (ACT) for nontraumatic abdominal pain in the pediatric emergency department is increasing to a remarkable extent, and every effort should be made to select patients who would benefit from ACT. The aim of this study was to investigate the clinical and laboratory predictors of positive CT yield in pediatric patients with nontraumatic abdominal pain.

METHODS

The medical records of 739 pediatric patients who, between January 2009 and February 2014, underwent ACT for nontraumatic abdominal pain at the emergency department were reviewed retrospectively. These patients were divided into 2 groups: a right lower quadrant (RLQ) pain group and a non-RLQ pain group. The radiology reports were reviewed to determine ACT diagnoses. Univariate and multivariate analysis was performed to elicit independent predictors of positive ACT yield. Equations predicting the probability of positive ACT diagnosis were deduced from the regression equation in both groups.

RESULTS

In the RLQ pain group, the most frequent ACT diagnosis was acute appendicitis, and in the non-RLQ pain group, enteritis was the most frequent diagnosis. In the RLQ pain group, sex, leukocytosis, neutrophil-to-lymphocyte ratio, and elevated C-reactive protein were significant independent predictors for positive ACT diagnosis. The number of synchronous predictor was significantly related to the proportion of positive ACT diagnosis. In the non-RLQ pain group, leukocytosis was the only significant predictor in multivariate analysis.

CONCLUSIONS

Factors predicting positive CT yield were sex, leukocytosis, neutrophil-to-lymphocyte ratio, and elevated C-reactive protein in the RLQ pain group and leukocytosis in the non-RLQ pain group.

Diagnostic Approach to Pediatric Spine Disorders

Understanding the developmental features of the pediatric spine and spinal cord, including embryologic steps and subsequent growth of the osteocartilaginous spine and contents is necessary for interpretation of the pathologic events that may affect the pediatric spine. MR imaging plays a crucial role in the diagnostic evaluation of patients suspected of harboring spinal abnormalities, whereas computed tomography and ultrasonography play a more limited, complementary role. This article discusses the embryologic and developmental anatomy features of the spine and spinal cord, together with some technical points and pitfalls, and the most common indications for pediatric spinal MR imaging.

The use of adaptive statistical iterative reconstruction (ASiR) technique in evaluation of patients with cervical spine trauma: impact on radiation dose reduction and image quality

OBJECTIVE

The aim of this study was to evaluate the impact of adaptive statistical iterative reconstruction (ASiR) technique on the image quality and radiation dose reduction. The comparison was made with the traditional filtered back projection (FBP) technique.

METHODS

We retrospectively reviewed 78 patients, who underwent cervical spine CT for blunt cervical trauma between 1 June 2010 and 30 November 2010. 48 patients were imaged using traditional FBP technique and the remaining 30 patients were imaged using the ASiR technique. The patient demographics, radiation dose, objective image signal and noise were recorded; while subjective noise, sharpness, diagnostic acceptability and artefacts were graded by two radiologists blinded to the techniques.

RESULTS

We found that the ASiR technique was able to reduce the volume CT dose index, dose-length product and effective dose by 36%, 36.5% and 36.5%, respectively, compared with the FBP technique. There was no significant difference in the image noise (p = 0.39), signal (p = 0.82) and signal-to-noise ratio (p = 0.56) between the groups. The subjective image quality was minimally better in the ASiR group but not statistically significant. There was excellent interobserver agreement on the subjective image quality and diagnostic acceptability for both groups.

CONCLUSION

The use of ASiR technique allowed approximately 36% radiation dose reduction in the evaluation of cervical spine without degrading the image quality.

ADVANCES IN KNOWLEDGE

The present study highlights that the ASiR technique is extremely helpful in reducing the patient radiation exposure while maintaining the image quality. It is highly recommended to utilize this novel technique in CT imaging of different body regions.

Quality in paediatric emergency medicine: Measurement and reporting

There is a clear demand for quality in the delivery of health care around the world; paediatric emergency medicine is no exception to this movement. It has been identified that gaps exist in the quality of acute care provided to children. Regulatory bodies in Australia and New Zealand are moving to mandate the implementation of quality targets and measures. Within the paediatric emergency department (ED), there is a lack of research into paediatric specific indicators. The existing literature regarding paediatric acute care quality measures has been recently summarised, and expert consensus has now been reported. It is clear that there is much work to be performed to generalise this work to ED. We review suggestions from the current literature relating to feasible indicators within the paediatric acute care setting. We propose options to develop a quality 'scorecard' that could be used to assist Australian and New Zealand EDs with quality measurement and benchmarking for their paediatric patients.

Computed tomography-related radiation exposure in children transferred to a Level I pediatric trauma center

PURPOSE

Pediatric trauma patients presenting to referring facilities (RF) often undergo computed tomography (CT) scans to identify injuries before transfer to a Level I pediatric trauma center (PTC). The purpose of our study was to evaluate RF compliance with the American College of Radiology (ACR) guidelines to minimize ionizing radiation exposure in pediatric trauma patients and to determine the frequency of additional or repeat CT imaging after transfer to a PTC.

METHODS

After institutional review board approval, a retrospective review of all pediatric trauma admissions from January 2010 to December 2011 at our American College of Surgeons Level I PTC was performed. Patient demographics, means of arrival, Injury Severity Score, and disposition were analyzed. Patients who underwent CT were grouped by means of arrival: those who were transferred from an RF versus those who presented primarily to the PTC. Compliance with ACR guidelines and need for additional or repeat CT scans were assessed for both groups.

RESULTS

Six hundred ninety-seven children (aged <18 years) were identified, with a mean age of 10.6 years. Three hundred twenty-one (46%) patients presented primarily to the PTC. Three hundred seventy-six (54%) were transferred from an RF, of which 90 (24%) patients underwent CT imaging before transfer. CT radiation dosing information was available for 79 (88%) of 90 patients. After transfer, 8 (9%) of 90 of children imaged at an RF required additional CT scans. In comparison, 314 (98%) of 321 patients who presented primarily to the PTC and underwent CT received appropriate pediatric radiation dosing. Mean radiation dose at PTC was approximately half of that at RF for CT scans of the head, chest, and abdomen/pelvis (p < 0.01).

CONCLUSION

Pediatric trauma patients transferred from RF often undergo CT scanning with higher than recommended radiation doses, potentially placing them at an increased carcinogenic risk. Fortunately, few RF patients required additional CT scans after PTC transfer. Finally, compliance with ACR radiation dose limit guidelines is better achieved at a PTC.

LEVEL OF EVIDENCE

Care management study, level IV.

Performance of CT examinations in children with suspected acute appendicitis in the community setting: a need for more education

OBJECTIVE

Despite a recent focus on the preferential use of ultrasound over CT for pediatric appendicitis, most children transferred from community hospitals still undergo diagnostic CT scans. The purpose of this study was to evaluate CT techniques performed for children with acute appendicitis at nonpediatric treatment centers.

MATERIALS AND METHODS

All patients treated for acute appendicitis at our tertiary-care pediatric hospital from July 1, 2011, through June 30, 2012, were identified. Patient demographics, imaging modality used to diagnoses appendicitis (CT or ultrasound), location (home or referral institution), and CT technique parameters were collected. The estimated mean organ radiation dose, number of imaging phases, and use of contrast media were evaluated at home and referral institutions.

RESULTS

During the study period, 1215 patients underwent appendectomies after imaging, with 442 (36.4%) imaged at referral facilities. Most referral patients received a diagnosis by CT (n=384, 87%), compared with 73 of 773 (9.4%) who received a diagnosis by CT at the home institution. The estimated mean (±SD) organ radiation dose was not statistically significantly different between home and referral institutions (13.5±7.3 vs 12.9±6.4 mGy; p=0.58) for single-phase examinations. Of 384 referral patients, 344 had images available for review. In total, 40% (138/344) of patients from referral centers were imaged with suboptimal CT techniques: 50 delayed phase only, 52 dual phase (eight of which were imaged twice in delayed phase), eight triple phase, and 36 without IV contrast agent.

CONCLUSION

CT parameters and radiation doses from single-phase examinations in children with appendicitis were similar at nonpediatric treatment centers and a tertiary care children's hospital. Future educational outreach should focus on optimizing other technical parameters.

Increasing utilization of abdominal CT in the Emergency Department of a secondary care center: does it produce better outcomes in caring for pediatric surgical patients?

PURPOSE

The use of abdominal computed tomography (ACT) utilization is increasing to a remarkable extent in the pediatric Emergency Department (ED), but the clinical benefit of increased use of ACT for pediatric surgical patients remains uncertain.

METHODS

A retrospective review was conducted to investigate if, for patients who had visited pediatric ED during the last 5 years, increasing utilization of ACT would increase the detection rate of acute appendicitis, increase the detection rate of surgical conditions other than appendicitis, and decrease the hospital admission rate for surgical conditions.

RESULTS

During the study period, there were 37,918 ED visits; of these, 3,274 (8.6%) were for abdominal pain, 844 (2.2%) had ACT performed. The annual proportional increase of the ACT was statistically significant (1.56% to 2.46%, P = 0.00), but the detection rate of acute appendicitis (3.3% to 5.1%) or other surgical conditions (1.7% to 2.8%) showed no statistically significant changes. Hospital admission rates (5.6% to 6.8%) also showed no significant changes during the study period.

CONCLUSION

Increasing utilization of ACT does not lead to the improved outcomes in caring for pediatric surgical patients visiting the pediatric ED. Careful evaluation for the indication for ACT is needed in the pediatric ED.

From 'Image Gently' to image intelligently: a personalized perspective on diagnostic radiation risk

The risk of ionizing radiation from diagnostic imaging has been a popular topic in the radiology literature and lay press. Communicating the magnitude of risk to patients and caregivers is problematic because of the uncertainty in estimates derived principally from epidemiological studies of large populations, and alternative approaches are needed to provide a scientific basis for personalized risk estimates. The underlying patient disease and life expectancy greatly influence risk projections. Research into the biological mechanisms of radiation-induced DNA damage and repair challenges the linear no-threshold dose-response assumption and reveals that individuals vary in sensitivity to radiation. Studies of decision-making psychology show that individuals are highly susceptible to irrational biases when judging risks. Truly informed medical decision-making that respects patient autonomy requires appropriate framing of radiation risks in perspective with other risks and with the benefits of imaging. To follow the principles of personalized medicine and treat patients according to their specific phenotypic and personality profiles, diagnostic imaging should optimally be tailored not only to patient size, body region and clinical indication, but also to underlying disease conditions, radio-sensitivity and risk perception and preferences that vary among individuals.

Outcomes and resource utilization associated with underage drinking at a level I trauma center

PURPOSE

To examine the association of blood alcohol content (BAC) on hospital-based outcomes and imaging utilization for patients <21 years admitted to a level I trauma center.

METHODS

Retrospective analysis of alcohol-involved injuries in patients 13-20 years, admitted to a level I trauma center from 1996 to 2010. An injury was considered alcohol involved if the patient had a BAC > 0. Multivariable logistic regression was used to compare mortality, discharge destination (home and skilled nursing facility), intensive care unit admission, and operating room use between patients with and without positive BAC for patients 13-15, 16-17, and 18-20 years. Multivariable linear regression was used to compare length of hospitalization. Finally, multivariable negative binomial regression evaluated radiology resource utilization (x-ray, computed tomography [CT], and magnetic resonance imaging).

RESULTS

A total of 7,663 patients, 13-20 years old, were admitted over the study period. A positive BAC was reported in 19% of these patients. In general, the presence of alcohol was not associated with mortality rate, length of hospitalization, intensive care unit, and operating room use or discharge status for any age group. However, the presence of alcohol was associated with higher utilization of head (incidence rate ratio [IRR] 1.13, 95% confidence interval [CI] 1.02-1.26), cervical spine (IRR 1.10, 95% CI 1.01-1.22), and thoracic (IRR 1.30, 95% CI 1.05-1.63) CTs in young adults 18-20 years. No differences in CT use were observed in patients 13-15 or 16-17 years.

CONCLUSIONS

Positive BAC was not significantly associated with adverse outcomes or resource utilization in younger trauma patients. However, the use of certain body region CTs was associated with positive BAC in patients 18-20 years.

Quality improvement in pediatric emergency medicine

Pediatric patients, who accounted for 17.4% of US emergency department (ED) visits in 2010, present unique challenges that can impede an ED's ability to provide optimal care. To meet the growing demand for comprehensive, high-quality care, health care systems are incorporating quality improvement (QI) methods to reduce costs and variations in care and to improve access, safety, and ultimately the outcomes of medical care. This overview of QI initiatives within the field of pediatric emergency medicine explores how proven QI strategies are being integrated into efforts that target the care of children within the broader emergency care community. These initiatives are categorized within the domains of education, infrastructures supporting QI efforts, research, and community/government collaborations. Professional societies supporting education, such as the American Academy of Pediatrics, have made several strides to cultivate new health leaders that will use QI methodology to improve outcomes in pediatric emergency care. In addition to educational pursuits, professional societies and QI organizations (eg, Children's Hospital Association) offer stable infrastructures from which QI initiatives, either disease specific or broadly targeted, can be implemented as large-scale QI initiatives (eg, quality collaboratives). This overview also provides examples of how QI methodology has been integrated into research strategies and describes how the pediatric emergency medicine community can spread innovation and best practices into the larger emergency care community.

Performance of ultrasound in the diagnosis of appendicitis in children in a multicenter cohort

OBJECTIVES

The objectives were to assess the test characteristics of ultrasound (US) in diagnosing appendicitis in children and to evaluate site-related variations based on the frequency of its use. Additionally, the authors assessed the test characteristics of US when the appendix was clearly visualized.

METHODS

This was a secondary analysis of a prospective, 10-center observational study. Children aged 3 to 18 years with acute abdominal pain concerning for appendicitis were enrolled. US was performed at the discretion of the treating physician.

RESULTS

Of 2,625 patients enrolled, 965 (36.8%) underwent abdominal US. US had an overall sensitivity of 72.5% (95% confidence interval [CI] = 58.8% to 86.3%) and specificity 97.0% (95% CI = 96.2% to 97.9%) in diagnosing appendicitis. US sensitivity was 77.7% at the three sites (combined) that used it in 90% of cases, 51.6% at a site that used it in 50% of cases, and 35% at the four remaining sites (combined) that used it in 9% of cases. US retained a high specificity of 96% to 99% at all sites. Of the 469 (48.6%) cases across sites where the appendix was clearly visualized on US, its sensitivity was 97.9% (95% CI = 95.2% to 99.9%), with a specificity of 91.7% (95% CI = 86.7% to 96.7%).

CONCLUSIONS

Ultrasound sensitivity and the rate of visualization of the appendix on US varied across sites and appeared to improve with more frequent use. US had universally high sensitivity and specificity when the appendix was clearly identified. Other diagnostic modalities should be considered when the appendix is not definitively visualized by US.

CT use in hospitalized pediatric trauma patients: 15-year trends in a level I pediatric and adult trauma center

PURPOSE

To evaluate the 15-year trend in the use of computed tomography (CT) in hospitalized pediatric trauma patients admitted to Harborview Medical Center (HMC) from 1996 to 2010.

MATERIALS AND METHODS

This Health Insurance Portability and Accountability Act-compliant retrospective study was approved by the institutional review board. The requirement for informed consent was waived. The HMC trauma registry was linked to the billing department data, and patient and injury-related characteristics were extracted, in addition to type and frequency of CT procedures. Patients discharged from the emergency department and patients hospitalized for less than 24 hours were not included in this study. Patients were classified into three categories according to age: 0-14 years, 15-18 years, and 19-54 years (reference group). Multivariate negative binomial regression was used to compare CT usage among different age groups by adjusting for patient sex, race and/or ethnicity, insurance status, mechanism of injury, injury severity, final disposition (dead vs alive), and year of admission. The trend for CT use in children and teenagers was also evaluated.

RESULTS

A total of 64 425 trauma patients 0-54 years of age were admitted during the study period. Compared with CT usage in adults 19-54 years old, usage in children up to 15 years of age was significantly lower for spine (incidence rate ratio [IRR], 0.89; 95% confidence interval [CI]: 0.85, 0.92), maxillofacial (IRR, 0.89; 95% CI: 0.81, 0.97), and thoracic (IRR, 0.91; 95% CI: 0.84, 0.99) CT. Increased use of head CT was observed in children up to 15 years old (IRR, 1.09; 95% CI: 1.05, 1.13) and 15-18 years old (IRR, 1.08; 95% CI: 1.04, 1.13). From 2008 to 2010, usage rates in children up to 15 years old and 15-18 years old was relatively unchanged or slightly decreased for almost all CT types.

CONCLUSION

A decreasing or unchanged trend was observed in CT usage in hospitalized pediatric trauma patients in recent years. © RSNA, 2013.

Iterative reconstruction techniques for computed tomography Part 1: technical principles

OBJECTIVES

To explain the technical principles of and differences between commercially available iterative reconstruction (IR) algorithms for computed tomography (CT) in non-mathematical terms for radiologists and clinicians.

METHODS

Technical details of the different proprietary IR techniques were distilled from available scientific articles and manufacturers' white papers and were verified by the manufacturers. Clinical results were obtained from a literature search spanning January 2006 to January 2012, including only original research papers concerning IR for CT.

RESULTS

IR for CT iteratively reduces noise and artefacts in either image space or raw data, or both. Reported dose reductions ranged from 23 % to 76 % compared to locally used default filtered back-projection (FBP) settings, with similar noise, artefacts, subjective, and objective image quality.

CONCLUSION

IR has the potential to allow reducing the radiation dose while preserving image quality. Disadvantages of IR include blotchy image appearance and longer computational time. Future studies need to address differences between IR algorithms for clinical low-dose CT.

KEY POINTS

• Iterative reconstruction technology for CT is presented in non-mathematical terms. • IR reduces noise and artefacts compared to filtered back-projection. • IR can improve image quality in routine-dose CT and lower the radiation dose. • IR's disadvantages include longer computation and blotchy appearance of some images.

The effect of abdominal pain duration on the accuracy of diagnostic imaging for pediatric appendicitis

STUDY OBJECTIVE

Advanced imaging with computed tomography (CT) or ultrasonography is frequently used to evaluate for appendicitis. The duration of the abdominal pain may be related to the stage of disease and therefore the interpretability of radiologic studies. Here, we investigate the influence of the duration of pain on the diagnostic accuracy of advanced imaging in children being evaluated for acute appendicitis.

METHODS

A secondary analysis of a prospective multicenter observational cohort of children aged 3 to 18 years with suspected appendicitis who underwent CT or ultrasonography was studied. Outcome was based on histopathology or telephone follow-up. Treating physicians recorded the duration of pain. Imaging was coded as positive, negative, or equivocal according to an attending radiologist's interpretation.

RESULTS

A total of 1,810 children were analyzed (49% boys, mean age 10.9 years [SD 3.8 years]); 1,216 (68%) were assessed by CT and 832 (46%) by ultrasonography (238 [13%] had both). The sensitivity of ultrasonography increased linearly with increasing pain duration (test for trend: odds ratio=1.39; 95% confidence interval 1.14 to 1.71). There was no association between the sensitivity of CT or specificity of either modality with pain duration. The proportion of equivocal CT readings significantly decreased with increasing pain duration (test for trend: odds ratio=0.76; 95% confidence interval 0.65 to 0.90).

CONCLUSION

The sensitivity of ultrasonography for appendicitis improves with a longer duration of abdominal pain, whereas CT demonstrated high sensitivity regardless of pain duration. Additionally, CT results (but not ultrasonographic results) were less likely to be equivocal with longer duration of abdominal pain.