Radiation Exposure From Diagnostic Imaging in Severely Injured Trauma Patients

Correlation Between Intra-Abdominal Free Fluid and Solid Organ Injury in Blunt Abdominal Trauma

Background:

In previous studies, the diagnostic value of Focused Assessment with Sonography for Trauma (FAST) has been evaluated but few studies have been performed on the relationship between the amount of free intra-abdominal fluid and organ injury in blunt abdominal trauma. To select patients with a higher probability of intra-abdominal injuries, several scoring systems have been proposed based on the results of FAST.

Objectives:

The aim of this study was to determine the prognostic value of FAST according to the Huang scoring system and to propose a cut-off point for predicting the presence of intra-abdominal injuries on the Computed Tomography (CT) scan. The correlation between age and Glasgow Coma Scale (GCS) and the presence of intra-abdominal injuries on the CT scan was also assessed.

Patients and Methods:

This study was performed on 200 patients with severe blunt abdominal trauma who had stable vital signs. For all patients, FAST-ultrasound was performed by a radiologist and the free fluid score in the abdomen was calculated according to the Huang score. Immediately, an intravenous contrast-enhanced abdominal CT scan was performed in all patients and abdominal solid organ injuries were assessed. Results were analyzed using Kruskal-Wallis test, Mann-Whitney test and ROC curves. The correlation between age and GCS and the presence of intra-abdominal injuries on CT-scan was also evaluated.

Results:

The mean age of the patients was 29.6 ± 18.3 years and FAST was positive in 67% of the subjects. A significant correlation was seen between the FAST score and the presence of organ injury on CT scan (P < 0.001). Considering the cut-off point of 3 for the free fluid score (with a range of 0-8), sensitivity, specificity, positive predictive value and negative predictive value were calculated to be 0.83, 0.98, 0.93, and 0.95, respectively. Age and GCS showed no significant correlation with intra-abdominal injuries.

Conclusions:

It seems that FAST examination for intra-abdominal fluid in blunt trauma patients can predict intra-abdominal injuries with very high sensitivity and specificity. Using the scoring system can more accurately determine the probability of the presence of abdominal injuries with a cut-off point of three.

"Occult" rib fractures diagnosed on computed tomography scan only are still a risk factor for solid organ injury

Introduction:

Prior to the widespread use of computed tomography (CT) scan imaging, lower rib fractures diagnosed on chest X-rays (CXRs) were considered a risk factor for abdominal solid organ injury (ASOI). However, CXRs miss about 50% of the rib fractures that are detected on CT scans. We hypothesized that these “occult” rib fractures would not be predictive for ASOI.

Materials and Methods:

Retrospective review of a level I trauma center's database identified all adult blunt trauma patients (n = 11,170) over a 5-year period. Data were abstracted for demographics, injury severity score, presence of ASOI, extremity, pelvic and spine fractures as well as presence and location of rib fractures.

Results:

Rib fractures correlated with the presence of ASOI, regardless of whether they were diagnosed by CXR or CT scan alone (P < 0.01). Middle (3-7) and lower (8-12) rib fractures, especially, correlated with the presence of ipsilateral ASOI (P < 0.0001).

Discussion:

Although CT scan detects more rib fractures than CXR, rib fractures remain a marker for increased likelihood of ASOI regardless of the modality by which they are diagnosed. Patients with rib fractures also have a greater incidence of spine and pelvic fractures. As the trauma community debates moving away from routine whole-body CT imaging towards a more selective approach, these results suggest that any clinical suspicion of rib fractures, despite a negative CXR, may warrant further investigation.

Split bolus technique in polytrauma: a prospective study on scan protocols for trauma analysis

BACKGROUND

For the evaluation of severely injured trauma patients a variety of total body computed tomography (CT) scanning protocols exist. Frequently multiple pass protocols are used. A split bolus contrast protocol can reduce the number of passes through the body, and thereby radiation exposure, in this relatively young and vitally threatened population.

PURPOSE

To evaluate three protocols for single pass total body scanning in 64-slice multidetector CT (MDCT) on optimal image quality.

MATERIAL AND METHODS

Three total body CT protocols were prospectively evaluated in three series of 10 consecutive trauma patients. In Group A unenhanced brain and cervical spine CT was followed by chest-abdomen-pelvis CT in portovenous phase after repositioning of the arms. Group B underwent brain CT followed without arm repositioning by a one-volume contrast CT from skull base to the pubic symphysis. Group C was identical to Group A, but the torso was scanned with a split bolus technique. Three radiologists independently evaluated protocol quality scores (5-point Likert scale), parenchymal and vascular enhancement and artifacts.

RESULTS

Overall image quality was good (4.10) in Group A, more than satisfactory (3.38) in Group B, and nearly excellent (4.75) in Group C (P < 0.001). Interfering artifacts were mostly reported in Group B in the liver and spleen.

CONCLUSION

In single pass total body CT scanning a split bolus technique reached the highest overall image quality compared to conventional total body CT and one-volume contrast CT.

Prior CT imaging history for patients who undergo PAN CT for acute traumatic injury

Objective. A single PAN scan may provide more radiation to a patient than is felt to be safe within a one-year period. Our objective was to determine how many patients admitted to the trauma service following a PAN scan had prior CT imaging within our six-hospital system.

Methods. We performed a secondary analysis of a prospectively collected trauma registry. The study was based at a level-two trauma center and five affiliated hospitals, which comprise 70.6% of all Emergency Department visits within a twelve county region of southern Texas. Electronic medical records were reviewed dating from the point of trauma evaluation back to December 5, 2005 to determine evidence of prior CT imaging.

Results. There were 867 patients were admitted to the trauma service between January 1, 2012 and December 31, 2012. 460 (53%) received a PAN scan and were included in the study group. The mean age of the study group was 37.7 ± 1.54 years old, 24.8% were female, and the mean ISS score was 13.4 ± 1.07. The most common mechanism of injury was motor vehicle collision (47%). 65 (14%; 95% CI [11–18]%) of the patients had at least one prior CT. The most common prior studies performed were: CT head (29%; 19–42%), CT Face (29%; 19–42%) and CT Abdomen and Pelvis (18%; 11–30%).

Conclusion. Within our trauma registry, 14% of patients had prior CT imaging within our hospital system before their traumatic event and PAN scan.

Whole-body CT-based imaging algorithm for multiple trauma patients: radiation dose and time to diagnosis

OBJECTIVE

To determine the number of imaging examinations, radiation dose and the time to complete trauma-related imaging in multiple trauma patients before and after introduction of whole-body CT (WBCT) into early trauma care.

METHODS

120 consecutive patients before and 120 patients after introduction of WBCT into the trauma algorithm of the University Hospital Zurich were compared regarding the number and type of CT, radiography, focused assessment with sonography for trauma (FAST), additional CT examinations (defined as CT of the same body regions after radiography and/or FAST) and the time to complete trauma-related imaging.

RESULTS

In the WBCT cohort, significantly more patients underwent CT of the head, neck, chest and abdomen (p < 0.001) than in the non-WBCT cohort, whereas the number of radiographic examinations of the cervical spine, chest and pelvis and of FAST examinations were significantly lower (p < 0.001). There were no significant differences between cohorts regarding the number of radiographic examinations of the upper (p = 0.56) and lower extremities (p = 0.30). We found significantly higher effective doses in the WBCT (29.5 mSv) than in the non-WBCT cohort (15.9 mSv; p < 0.001), but fewer additional CT examinations for completing the work-up were needed in the WBCT cohort (p < 0.001). The time to complete trauma-related imaging was significantly shorter in the WBCT (12 min) than in the non-WBCT cohort (75 min; p < 0.001).

CONCLUSION

Including WBCT in the initial work-up of trauma patients results in higher radiation doses, but fewer additional CT examinations are needed, and the time for completing trauma-related imaging is shorter.

ADVANCES IN KNOWLEDGE

WBCT in trauma patients is associated with a high radiation dose of 29.5 mSv.

Whole-body computed tomographic scanning leads to better survival as opposed to selective scanning in trauma patients: a systematic review and meta-analysis

BACKGROUND

Traumatic injury in the United States is the Number 1 cause of mortality for patients 1 year to 44 years of age. Studies suggest that early identification of major injury leads to better outcomes for patients. Imaging, such as computed tomography (CT), is routinely used to help determine the presence of major underlying injuries. We review the literature to determine whether whole-body CT (WBCT), a protocol including a noncontrast scan of the brain and neck and a contrast-enhanced scan of the chest, abdomen, and pelvis, detects more clinically significant injuries as opposed to selective scanning as determined by mortality rates.

METHODS

Scientific publications from 1980 to 2013 involving the study of the difference between pan scan and selective scan after trauma were identified. The Preferred Reporting Items for Systematic Reviews and Meta-analyses was used. Publications were categorized by level of evidence. Injury Severity Score (ISS) and pooled odds for mortality rate of patients who received WBCT scan versus those who received selective scans were compared.

RESULTS

Of the 465 publications identified, 7 were included, composing of 25,782 trauma patients who received CT scan following trauma. Of the patients, 52% (n = 13,477) received pan scan and 48% (n = 12,305) received selective scanning. Overall ISS was significantly higher for patients receiving WBCT versus those receiving selective scan (29.7 vs. 26.4, p < 0.001, respectively). Overall mortality rate was significantly lower for WBCT versus selective scanning (16.9; 95% confidence interval [CI], 16.3-17.6 vs. 20.3; 95% CI, 19.6-21.1, p < 0.0002, respectively). Pooled odds ratio for mortality rate was 0.75 (95% CI, 0.7-0.79), favoring WBCT.

CONCLUSION

Despite the WBCT group having significantly higher ISS at baseline compared with the group who received selective scanning, the WBCT group had a lower overall mortality rate and a more favorable pooled odds ratio for trauma patients. This suggests that in terms of overall mortality, WBCT scan is preferable to selective scanning in trauma patients.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Cumulative radiation dose due to diagnostic investigations in seriously injured trauma patients admitted to critical care

A retrospective review of case notes and radiology records was performed in order to estimate the amount and sources of ionising radiation multiply injured trauma patients are exposed to, during their initial investigations and subsequent critical care admission. Data were available for 431 radiological investigations from 36 patients. Results showed initial emergency department imaging (combined computed tomography (CT) and plain radiographs) contributed 70% of the total radiation dose. Overall, CT scans were responsible for 80% and plain radiographs 15% of the total radiation dose. Plain radiographs performed after the initial resuscitation period contributed the greatest number of investigations but accounted for only 8% of total radiation exposure. Median cumulative effective dose was estimated to be between 16 and 29 millisieverts, resulting in an estimated increased life time risk of carcinogenesis of between 1 in 614 and 1 in 1075 above baseline.

Cumulative effective dose associated with computed tomography examinations in adolescent trauma patients

OBJECTIVES

The aims of this study were to analyze cumulative effective dose (cED) and to assess lifetime attributable risk (LAR) of cancer due to radiation exposure during computed tomography (CT) examinations in adolescent trauma patients.

METHODS

Between January 2010 and May 2011, the adolescent patients with trauma were enrolled in this study. Numbers of CT examinations and body regions examined were collated, and cEDs were calculated using dose-length product values and conversion factors. Lifetime attributable risk for cancer incidence and cancer-associated mortality were quantified based on the studies of survivors of the atomic bombs on Japan. Data were stratified according to severity of trauma: minor trauma, injury severity score of less than 16; and major trauma, injury severity score of 16 or greater.

RESULTS

A total of 698 CT scans were obtained on the following regions of 484 adolescent patients: head CT, n = 647; rest of the body, n = 41; and thorax, n = 10. Mean cED per patient was 3.4 mSv, and mean LARs for cancer incidence and mortality were 0.05% and 0.02%, respectively. The majority of patients (98.4%) experienced minor trauma, and their mean cED and LARs for cancer incidence and mortality (3.0 mSv and 0.04% and 0.02%, respectively) were significantly lower than those of patients with major trauma (24.3 mSv and 0.31% and 0.15%, respectively, all P values < 0.001).

CONCLUSIONS

The overall radiation-induced cancer risk due to CT examinations performed for the initial assessment of minor trauma was found to be relatively low in adolescent patients. However, adolescent patients with major trauma were exposed to a substantial amount of radiation during multiple CT examinations.

Establishment and implementation of an effective rule for the interpretation of computed tomography scans by emergency physicians in blunt trauma

Introduction

Computed tomography (CT) can detect subtle organ injury and is applicable to many body regions. However, its interpretation requires significant skill. In our hospital, emergency physicians (EPs) must interpret emergency CT scans and formulate a plan for managing most trauma cases. CT misinterpretation should be avoided, but we were initially unable to completely accomplish this. In this study, we proposed and implemented a precautionary rule for our EPs to prevent misinterpretation of CT scans in blunt trauma cases.

Methods

We established a simple precautionary rule, which advises EPs to interpret CT scans with particular care when a complicated injury is suspected per the following criteria: 1) unstable physiological condition; 2) suspicion of injuries in multiple regions of the body (e.g., brain injury plus abdominal injury); 3) high energy injury mechanism; and 4) requirement for rapid movement to other rooms for invasive treatment. If a patient meets at least one of these criteria, the EP should exercise the precautions laid out in our newly established rule when interpreting the CT scan. Additionally, our rule specifies that the EP should request real-time interpretation by a radiologist in difficult cases. We compared the accuracy of EPs’ interpretations and resulting patient outcomes in blunt trauma cases before (January 2011, June 2012) and after (July 2012, January 2013) introduction of the rule to evaluate its efficacy.

Results

Before the rule’s introduction, emergency CT was performed 1606 times for 365 patients. We identified 44 cases (2.7%) of minor misinterpretation and 40 (2.5%) of major misinterpretation. After introduction, CT was performed 820 times for 177 patients. We identified 10 cases (1.2%) of minor misinterpretation and two (0.2%) of major misinterpretation. Real-time support by a radiologist was requested 104 times (12.7% of all cases) and was effective in preventing misinterpretation in every case. Our rule decreased both minor and major misinterpretations in a statistically significant manner. In particular, it conspicuously decreased major misinterpretations.

Conclusion

Our rule was easy to practice and effective in preventing EPs from missing major organ injuries. We would like to propose further large-scale multi-center trials to corroborate these results.

Systematic review of the benefits and harms of whole-body computed tomography in the early management of multitrauma patients: are we getting the whole picture?

BACKGROUND

There is considerable interest in whether routine whole-body computed tomography (WBCT) imaging produces different patient outcomes in blunt trauma patients when compared with selective imaging. This article aimed to systematically review the literature for all outcomes measured in comparing WBCT with selective imaging in trauma patients and to evaluate the comprehensiveness of relevant dimensions for this comparison.

METHODS

We performed a systematic review of studies comparing WBCT and selective imaging approaches during the initial assessment of multitrauma patients. Peer-reviewed studies including cohort studies, randomized controlled trials, meta-analyses, and systematic reviews were identified through large database searches and filtered through methodologic inclusion criteria. Data on study characteristics, hypotheses and conclusions made, outcomes assessed, and references to potential benefits and harms were extracted.

RESULTS

Eight retrospective cohort studies and two systematic reviews were identified. Six primary studies evaluated mortality as an outcome, and four studies found a significant difference in results favoring WBCT imaging over selective imaging. All five articles assessing various time intervals in hospital following imaging after injury found significantly reduced times with WBCT. Radiation exposure was found to be increased after WBCT imaging compared with selective imaging in the only study in which it was evaluated. The two systematic reviews analyzed the same three articles with regard to mortality but concluded differently about overall benefits.

CONCLUSION

WBCT imaging seems to be associated with reduced times to events in hospital following traumatic injury and seems to be associated with decreased mortality. Whether this is a true effect mediated through an as yet unsubstantiated change in management or the result of hospital- or individual-level confounders is unclear. When evaluating these outcomes, it seems that the authors of both primary studies and systematic reviews have often been selective in their choice of short-term outcomes, painting an incomplete picture of the issue.

LEVEL OF EVIDENCE

Systematic review, level III.

Consequences of increased use of computed tomography imaging for trauma patients in rural referring hospitals prior to transfer to a regional trauma centre

BACKGROUND

Computed tomography (CT) plays an integral role in the evaluation and management of trauma patients. As the number of referring hospital (RH)-based CT scanners increased, so has their utilization in trauma patients before transfer. We hypothesized that this has resulted in increased time at RH, image duplication, and radiation dose.

METHODS

A retrospective chart review was completed for trauma activations transferred to an ACS-verified Level II Trauma Centre (TC) during two time periods: 2002-2004 (Group 1) and 2006-2008 (Group 2). 2005 data were excluded as this marked the transition period for acquisition of hospital-based CT scanners in RH. Statistical analysis included t test and χ(2) analysis. P<0.05 was considered significant.

RESULTS

1017 patients met study criteria: 503 in group 1 and 514 in group 2. Mean age was greater in group 2 compared to group 1 (40.3 versus 37.4, respectively; P=0.028). There were 115 patients in group 1 versus 202 patients in group 2 who underwent CT imaging at RH (P<0.001). Conversely, 326 patients in group 1 had CT scans performed at the TC versus 258 patients in group 2 (P<0.001). Mean time at the RH was similar between the groups (117.1 and 112.3min for group 1 and 2, respectively; P=0.561). However, when comparing patients with and without a pretransfer CT at the RH, the median time at RH was 140 versus 67min, respectively (P<0.001). The number of patients with duplicate CT imaging (n=34 in group 1 and n=42 in group 2) was not significantly different between the two time periods (P=0.392). Head CTs comprised the majority of duplicate CT imaging in both time periods (82.4% in group 1 and 90.5% in group 2). Mean total estimated radiation dose per patient was not significantly different between the two groups (group 1=8.4mSv versus group 2=7.8mSv; P=0.192).

CONCLUSIONS

A significant increase in CT imaging at the RH prior to transfer to the TC was observed over the study periods. No associated increases in mean time at the RH, image duplication at TC, total estimated radiation dose per patient, and mortality rate were observed.

Dose reduction in whole-body computed tomography of multiple injuries (DoReMI): protocol for a prospective cohort study

BACKGROUND

Single-pass, contrast-enhanced whole body multidetector computed tomography (MDCT) emerged as the diagnostic standard for evaluating patients with major trauma. Modern iterative image algorithms showed high image quality at a much lower radiation dose in the non-trauma setting. This study aims at investigating whether the radiation dose can safely be reduced in trauma patients without compromising the diagnostic accuracy and image quality.

METHODS/DESIGN

Prospective observational study with two consecutive cohorts of patients.

SETTING

A high-volume, academic, supra-regional trauma centre in Germany.

STUDY POPULATION

Consecutive male and female patients who 1. had been exposed to a high-velocity trauma mechanism, 2. present with clinical evidence or high suspicion of multiple trauma (predicted Injury Severity Score [ISS] ≥16) and 3. are scheduled for primary MDCT based on the decision of the trauma leader on call.Imaging protocols: In a before/after design, a consecutive series of 500 patients will undergo single-pass, whole-body 128-row multi-detector computed tomography (MDCT) with a standard, as low as possible radiation dose. This will be followed by a consecutive series of 500 patients undergoing an approved ultra-low dose MDCT protocol using an image processing algorithm.

DATA

Routine administrative data and electronic patient records, as well as digital images stored in a picture archiving and communications system will serve as the primary data source. The protocol was approved by the institutional review board.

MAIN OUTCOMES

(1) incidence of delayed diagnoses, (2) diagnostic accuracy, as correlated to the reference standard of a synopsis of all subsequent clinical, imaging, surgical and autopsy findings, (3) patients' safety, (4) radiation exposure (e.g. effective dose), (5) subjective image quality (assessed independently radiologists and trauma surgeons on a 100-mm visual analogue scale), (6) objective image quality (e.g., contrast-to-noise ratio).

ANALYSIS

Multivariate regression will be employed to adjust and correct the findings for time and cohort effects. An exploratory interim analysis halfway after introduction of low-dose MDCT will be conducted to assess whether this protocol is clearly inferior or superior to the current standard.

DISCUSSION

Although non-experimental, this study will generate first large-scale data on the utility of imaging-enhancing algorithms in whole-body MDCT for major blunt trauma.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN74557102.

Cumulative total effective whole-body radiation dose in critically ill patients

BACKGROUND

Uncertainty exists about a safe dose limit to minimize radiation-induced cancer. Maximum occupational exposure is 20 mSv/y averaged over 5 years with no more than 50 mSv in any single year. Radiation exposure to the general population is less, but the average dose in the United States has doubled in the past 30 years, largely from medical radiation exposure. We hypothesized that patients in a mixed-use surgical ICU (SICU) approach or exceed this limit and that trauma patients were more likely to exceed 50 mSv because of frequent diagnostic imaging.

METHODS

Patients admitted into 15 predesignated SICU beds in a level I trauma center during a 30-day consecutive period were prospectively observed. Effective dose was determined using Huda's method for all radiography, CT imaging, and fluoroscopic examinations. Univariate and multivariable linear regressions were used to analyze the relationships between observed values and outcomes.

RESULTS

Five of 74 patients (6.8%) exceeded exposures of 50 mSv. Univariate analysis showed trauma designation, length of stay, number of CT scans, fluoroscopy minutes, and number of general radiographs were all associated with increased doses, leading to exceeding occupational exposure limits. In a multivariable analysis, only the number of CT scans and fluoroscopy minutes remained significantly associated with increased whole-body radiation dose.

CONCLUSIONS

Radiation levels frequently exceeded occupational exposure standards. CT imaging contributed the most exposure. Health-care providers must practice efficient stewardship of radiologic imaging in all critically ill and injured patients. Diagnostic benefit must always be weighed against the risk of cumulative radiation dose.

Low-dose ionising radiation from medical imaging in patients hospitalised in Internal Medicine

BACKGROUND

Medical imaging is responsible for increasing exposure to low-dose ionising radiation in the general population. The extent of exposure in specific patient populations remains to be determined.

AIM

We sought to determine the level of exposure in patients hospitalised in General Internal Medicine.

METHODS

In this retrospective cohort study, we searched the Centre Informatisé de Recherche Évaluative en Services et Soins de Santé database for adult patients hospitalised in General Internal Medicine from 1 January 2008 to 31 December 2008. We collected data on demographics, co-morbidities, and radiological and nuclear imaging. We used data from the literature to calculate an estimated annual effective dose for each patient and searched for factors associated with higher exposure.

RESULTS

One thousand one hundred eighty-seven (1187) patients were hospitalised at least once during the study period. The median age was 69 years (interquartile range 56-81) and 636 (53.6%) were men. The median annual effective dose of the whole cohort was 8.7 mSv/year. Patients aged between 55 and 80 years were exposed to a higher median effective dose compared with their younger and older counterparts (P < 0.001). Patients with cardiac, pulmonary, peripheral arterial and neoplastic disease were at higher risk of exposure to high and very high annual effective dose (P < 0.01). Patients with longer hospitalisations were at higher risk of exposure to high and very high annual effective dose (P < 0.01).

CONCLUSION

Patients hospitalised on a General Internal Medicine ward are exposed to three times more ionising radiation than the general population.

Analysis of radiation exposure among pediatric trauma patients at national trauma centers

BACKGROUND

Injured children undergo radiologic studies as part of trauma evaluations. Children are more sensitive than adult patients to the effects of ionizing radiation. Few studies have described the radiation exposure to pediatric patients during trauma evaluations. We sought to describe the rate of use of radiology studies and to estimate the effective dose of radiation delivered to pediatric trauma patients presenting to trauma centers within the United States.

METHODS

We performed an analysis of pediatric patients younger than 19 years who presented to an American College of Surgery-verified trauma center in 2010 (National Trauma Data Bank). We excluded patients who were transferred from another facility, patients who died at the scene or those who presented to the emergency department dead on arrival. We examined the use of computed tomography (CT) and standard radiographs (x-ray). Radiologic studies were identified through common procedure codes (CPT). Using published criteria, we estimated the effective radiation dose per trauma patient.

RESULTS

Among the 84,863 eligible pediatric trauma patients, 26,360 (31.1%) underwent imaging with x-ray or CT. Of these patients, 17,321 (65.7%) were male, median age was 13.0 years (interquartile range, 6.0-17.0), and 20,965 (79.5%) had an Injury Severity Score (ISS) of less than 16. A total of 23,148 (27.4%) underwent CT. X-ray studies accounted for a small amount of exposure to radiation as compared with CT. Mean (SD) effective radiation exposure of patients imaged with CT was 12.0 (8.2) mSv. Younger children and those with increasing injury severity were exposed to higher doses of radiation (β = -0.04, p < 0.001).

CONCLUSION

The majority of radiation exposure to pediatric trauma patients is secondary to CT. Younger children and those with more severe injuries are exposed to higher doses of radiation. Pediatric trauma patients are exposed to levels of radiation, which could potentially lead to long-term harm.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Do we glow? Evaluation of trauma team work habits and radiation exposure

BACKGROUND

Health care workers' potential exposure to ionizing radiation has increased. Annual radiation exposure limit for the general public per US Nuclear Regulatory Commission is 100 mrem (1 mSv). The whole-body annual occupational radiation exposure limit is 5,000 mrem (50 mSv). Studies have been done to evaluate patient radiation exposure. To date, there has been no study to evaluate the radiation exposure of trauma team members or evaluate their behaviors and attitudes.

METHODS

Forty primary providers (residents, physician assistants) rotating on the trauma service at an American College of Surgeons Level 1 trauma center participated. Dosimeters were worn by participants, and the radiation doses were measured monthly. A survey detailing the frequency of involvement in radiographic studies, use of protective equipment, and knowledge of education programs was completed monthly.

RESULTS

The range of radiation measured was 1 mrem to 56 mrem, with an average effective dose of 10 mrem per month. Thirty-two (80%) of 40 reported daily exposure to x-rays and 28 (70%) of 40 to computed tomographic scans. Thirty-four (85%) of 40 reported that they never or seldom wore lead apron in trauma bay as opposed to 1 (3%) of 40 who failed to wear it during fluoroscopy. Twenty (50%) reported that an apron was not available, while 20 (50%) reported that it was too hot or did not fit. Thirty-nine (97%) of 40 reported that they received training in radiation safety.

CONCLUSION

Despite inconsistent use of protective equipment by resident staff, the actual radiation exposure remains low. Hospitals should be sure lead aprons and collars are available. Additional education concerning the availability of programs during pregnancy is needed.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Evaluation for intra-abdominal injury in children after blunt torso trauma: can we reduce unnecessary abdominal computed tomography by utilizing a clinical prediction model?

BACKGROUND

Blunt trauma is a leading cause of morbidity and mortality in children. Despite the potential for malignancy, increased cost, limited small bowel injury detection sensitivity, and the low incidence of injury requiring operative intervention, the use of computed tomographic (CT) scan in pediatric blunt trauma evaluation remains common. Previous studies suggest that a clinical model using examination and laboratory data may help predict intra-abdominal injuries (IAIs) and potentially limit unnecessary CT scans in children.

METHODS

A retrospective chart review of all blunt "trauma alerts" for patients younger than 16 years during an 18-month period was performed at a Level I trauma center. Clinical factors, which might predict blunt IAI (hemodynamics, abdominal examination, serology, and plain radiographs), and potential limitations to performing a reliable abdominal examination (altered mental status, young age) were reviewed. A previously defined clinical prediction model based on six high-risk clinical variables for blunt IAI (hypotension, abnormal abdominal examination, elevated aspartate aminotransferase, elevated amylase, low hematocrit, and heme-positive urinalysis) was applied to each patient.

RESULTS

Of the 125 "trauma alert" patients who sustained blunt trauma during the study period, 97 underwent abdominal CT scan, with only 15 identified as IAI. Our prediction rule would have identified 16 of 17 patients with IAI (SE, 94%) as high-risk and missed only 1 patient (grade I spleen laceration, which did not require operation) (negative predictive value, 99%). Of the 83 patients with no risk factors for IAI based on the prediction rule, 54 underwent a negative abdominal CT scan. Of these 54 patients, only 22 had a potential limitation to a reliable abdominal examination. Application of our prediction rule could have prevented unnecessary CT scan in at least 32 patients (33%) during an 18-month period.

CONCLUSION

Use of a prediction model based on high-risk variables for IAI may decrease cost and radiation exposure by reducing the number of abdominal CT scans in children being evaluated for blunt abdominal trauma.

The role of computed tomography in musculoskeletal trauma

Computed tomography is the undisputed gold standard in the imaging of acute trauma, despite the introduction of focused assessment with sonography for trauma and magnetic resonance imaging. However, the role of computed tomography is far wider than just polytrauma imaging: its high spatial resolution, short scan times and very high sensitivity and specificities make computed tomography useful in the diagnosis of subtle injuries, as well as providing a general overview of other compartmental injuries. Three-dimensional reconstructions illustrates complex injury patterns clearly, aiding surgical planning and permitting accurate orthopaedic hardware follow-up. This article outlines some of the basic properties of computed tomography using examples from musculoskeletal trauma, to illustrate to clinicians what computed tomography can and cannot do for their practice.

Plain Radiography May Be Safely Omitted for Selected Major Trauma Patients Undergoing Whole Body CT: Database Study

Introduction. Whole body CT is being used increasingly in the primary survey of major trauma patients. We evaluated whether omitting plain films of the chest and pelvis in the primary survey was safe. We compared the probability of survival of patients and time to CT who had plain X-rays to those who did not. Method. We performed a database study on major trauma patients admitted between 2008 and 2010 using data from Trauma, Audit and Research Network (TARN) and our PACS system. We included adult major trauma patients who has an ISS of greater than 15 and underwent whole body CT. Results. 245 patients were included in the study. 44 (17.9%) did not undergo plain films. The median time to whole body CT from the time of admission was longer (47 minutes) in patients having plain films, than those who did not have plain films performed (30 minutes), P < 0.005. Mortality was increased in the group who received plain films, 9.5% compared to 4.5%, but this was not statistically significant (P = 0.77). Conclusion. We conclude that plain films may be safely omitted during the primary survey of selected major trauma patients.

Evaluation of radiation dose among patients admitted through a university hospital emergency department

This study was conducted to evaluate the impact of different patient presentations/characteristics on medical imaging and radiation exposure. We collected data on the estimated effective radiation dose (EED) of patients admitted through our University Hospital ER, and analyzed the relationships of patient gender, age, admitting diagnosis, and admission duration on EED. All (592) patients admitted through our ER (with imaging) during 1-week periods in May/November 2009 were included. To compare EEDs according to admission diagnosis, seven categories were created: Cardiopulmonary, Gastrointestinal, Genitourinary, Neurologic, Trauma, Infectious, and Other. EEDs of patients with various admission durations were also evaluated. Units for all EEDs are mSv. Median EED (MEED) for all patients was 4.5. Males (7.8, females = 2.5) and adults (6.1, pediatrics = 1.8) experienced higher MEEDs, but significance was lost after controlling for other variables. MEED increased with admission duration (0.1 for <24 h, 1.8 for 1-3 days and 92.0 for >2 months). Trauma patients experienced the highest MEED (18.3), while patients with gastrointestinal/genitourinary diagnoses experienced the second highest MEED (13.0 mSv for both). Pediatric/male patients experienced heightened radiation exposure, but these relationships were largely due to other variables (higher male frequency/severity of trauma, pediatric patients had shorter admissions and diagnoses requiring less radiologic workup). Patients admitted following trauma and for prolonged durations showed elevated radiation exposure even after adjustment for all other variables. The identification of these relationships may aid in the development and focusing of future radiation awareness/reduction efforts to persons involved in the evaluation and care of patients with these presentations and characteristics.

Radiation associated tumors following therapeutic cranial radiation

BACKGROUND

A serious, albeit rare, sequel of therapeutic ionizing radiotherapy is delayed development of a new, histologically distinct neoplasm within the radiation field.

METHODS

We identified 27 cases, from a 10-year period, of intracranial tumors arising after cranial irradiation. The original lesions for which cranial radiation was used for treatment included: tinea capitis (1), acute lymphoblastic leukemia (ALL; 5), sarcoma (1), scalp hemangioma (1), cranial nerve schwannoma (1) and primary (13) and metastatic (1) brain tumors, pituitary tumor (1), germinoma (1), pinealoma (1), and unknown histology (1). Dose of cranial irradiation ranged from 1800 to 6500 cGy, with a mean of 4596 cGy. Age at cranial irradiation ranged from 1 month to 43 years, with a mean of 13.4 years.

RESULTS

Latency between radiotherapy and diagnosis of a radiation-induced neoplasm ranged from 4 to 47 years (mean 18.8 years). Radiation-induced tumors included: meningiomas (14), sarcomas (7), malignant astrocytomas (4), and medulloblastomas (2). Data were analyzed to evaluate possible correlations between gender, age at irradiation, dose of irradiation, latency, use of chemotherapy, and radiation-induced neoplasm histology. Significant correlations existed between age at cranial irradiation and development of either a benign neoplasm (mean age 8.5 years) versus a malignant neoplasm (mean age 20.3; P = 0.012), and development of either a meningioma (mean age 7.0 years) or a sarcoma (mean age 27.4 years; P = 0.0001). There was also a significant positive correlation between latency and development of either a meningioma (mean latency 21.8 years) or a sarcoma (mean latency 7.7 years; P = 0.001). The correlation between dose of cranial irradiation and development of either a meningioma (mean dose 4128 cGy) or a sarcoma (mean dose 5631 cGy) approached significance (P = 0.059).

CONCLUSIONS

Our study is the first to show that younger patients had a longer latency period and were more likely to have lower-grade lesions (e.g. meningiomas) as a secondary neoplasm, while older patients had a shorter latency period and were more likely to have higher-grade lesions (e.g. sarcomas).

Systematic review and meta-analysis of immediate total-body computed tomography compared with selective radiological imaging of injured patients

BACKGROUND

The aim of this review was to assess the value of immediate total-body computed tomography (CT) during the primary survey of injured patients compared with conventional radiographic imaging supplemented with selective CT.

METHODS

A systematic search of the literature was performed in MEDLINE, Embase, Web of Science and Cochrane Library databases. Reports were eligible if they contained original data comparing immediate total-body CT with conventional imaging supplemented with selective CT in injured patients. The main outcomes of interest were overall mortality and time in the emergency room (ER).

RESULTS

Four studies were included describing a total of 5470 patients; one study provided 4621 patients (84.5 per cent). All four studies were non-randomized cohort studies with retrospective data collection. Mortality was reported in three studies. Absolute mortality rates differed substantially between studies, but within studies mortality rates were comparable between immediate total-body CT and conventional imaging strategies (pooled odds ratio 0.91, 95 per cent confidence interval 0.79 to 1.05). Time in the ER was described in three studies, and in two was significantly shorter in patients who underwent immediate total-body CT: 70 versus 104 min (P = 0.025) and 47 versus 82 min (P < 0.001) respectively.

CONCLUSION

This review showed differences in time in the ER in favour of immediate total-body CT during the primary trauma survey compared with conventional radiographic imaging supplemented with selective CT. There were no differences in mortality. The substantial reduction in time in the ER is a promising feature of immediate total-body CT but well designed and larger randomized studies are needed to see how this will translate into clinical outcomes.

A multicenter, randomized controlled trial of immediate total-body CT scanning in trauma patients (REACT-2)

BACKGROUND

Computed tomography (CT) scanning has become essential in the early diagnostic phase of trauma care because of its high diagnostic accuracy. The introduction of multi-slice CT scanners and infrastructural improvements made total-body CT scanning technically feasible and its usage is currently becoming common practice in several trauma centers. However, literature provides limited evidence whether immediate total-body CT leads to better clinical outcome then conventional radiographic imaging supplemented with selective CT scanning in trauma patients. The aim of the REACT-2 trial is to determine the value of immediate total-body CT scanning in trauma patients.

METHODS/DESIGN

The REACT-2 trial is an international, multicenter randomized clinical trial. All participating trauma centers have a multi-slice CT scanner located in the trauma room or at the Emergency Department (ED). All adult, non-pregnant, severely injured trauma patients according to predefined criteria will be included. Patients in whom direct scanning will hamper necessary cardiopulmonary resuscitation or who require an immediate operation because of imminent death (both as judged by the trauma team leader) are excluded. Randomization will be computer assisted. The intervention group will receive a contrast-enhanced total-body CT scan (head to pelvis) during the primary survey. The control group will be evaluated according to local conventional trauma imaging protocols (based on ATLS guidelines) supplemented with selective CT scanning. Primary outcome will be in-hospital mortality. Secondary outcomes are differences in mortality and morbidity during the first year post trauma, several trauma work-up time intervals, radiation exposure, general health and quality of life at 6 and 12 months post trauma and cost-effectiveness.

DISCUSSION

The REACT-2 trial is a multicenter randomized clinical trial that will provide evidence on the value of immediate total-body CT scanning during the primary survey of severely injured trauma patients. If immediate total-body CT scanning is found to be the best imaging strategy in severely injured trauma patients it could replace conventional imaging supplemented with CT in this specific group.

TRIAL REGISTRATION

ClinicalTrials.gov: (NCT01523626).

Clinical review: Spinal imaging for the adult obtunded blunt trauma patient: update from 2004

PURPOSE

Controversy exists over how to 'clear' (we mean enable the clinician to safely remove spinal precautions based on imaging and/or clinical examination) the spine of significant unstable injury among clinically unevaluable obtunded blunt trauma patients (OBTPs). This review provides a clinically relevant update of the available evidence since our last review and practice recommendations in 2004.

METHODS

Medline, Embase. Google Scholar, BestBETs, the trip database, BMJ clinical evidence and the Cochrane library were searched. Bibliographies of relevant studies were reviewed.

RESULTS

Plain radiography has low sensitivity for detecting unstable spinal injuries in OBTPs whereas multidetector-row computerised tomography (MDCT) approaches 100%. Magnetic resonance imaging (MRI) is inferior to MDCT for detecting bony injury but superior for detecting soft tissue injury with a sensitivity approaching 100%, although 40% of such injuries may be stable and 'false positive'. For studies comparing MDCT with MRI for OBTPs; MRI following 'normal' CT may detect up to 7.5% missed injuries with an operative fixation in 0.29% and prolonged collar application in 4.3%. Increasing data is available on the complications associated with prolonged spinal immobilisation among a population where a minority have an actual injury.

CONCLUSIONS

Given the variability of screening performance it remains acceptable for clinicians to clear the spine of OBTPs using MDCT alone or MDCT followed by MRI, with implications to either approach. Ongoing research is needed and suggestions are made regarding this. It is essential clinicians and institutions audit their data to determine their likely screening performances in practice.

A systematic review and meta-analysis of diagnostic screening criteria for blunt cerebrovascular injuries

BACKGROUND

Despite progress in diagnosing and managing blunt cerebrovascular injury (BCVI), controversy remains regarding the appropriate population to screen. A systematic review of published literature was conducted to summarize the overall incidence of BCVI and the various screening criteria used to detect BCVI. A meta-analysis was performed to evaluate which screening criteria may be associated with BCVI. Goals were to confirm inclusion of certain criteria in current screening protocols and possibly eliminate criteria not associated with BCVI.

STUDY DESIGN

Studies published between January 1995 and April 2011 using digital subtraction angiography or CT angiography as a diagnostic modality and reporting overall BCVI incidence or prevalence of BCVI for specific screening criteria were examined. Screening criteria were analyzed using a random effects model to determine if an association with BCVI was present.

RESULTS

The incidence range of BCVI was between 0.18% and 2.70% among approximately 122,176 blunt trauma admissions. The meta-analysis encompassed 418 BCVI and 22,568 non-BCVI patients. Of the 9 screening criteria analyzed, cervical spine (odds ratio [OR] 5.45; 95% CI 2.24 to 13.27; p < 0.0001) and thoracic (OR 1.98; 95% CI 1.35 to 2.92; p = 0.001) injuries demonstrated a significant association with BCVI.

CONCLUSIONS

Patients with cervical spine and thoracic injuries had significantly greater likelihoods of BCVI compared with patients without these injuries. All patients with either injury should be screened for BCVI. Multivariate logistic regression analysis is needed to elucidate the possible impact of the combined presence of screening criteria, but it was not possible in our study due to limitations in data presentation. Standardized reporting of BCVI data is not established and is recommended to permit future collaboration.

Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

BACKGROUND

The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose.

METHODS

One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population.

RESULTS

Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters.

CONCLUSIONS

A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques.

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

An increasing number of patients presenting to a shrinking number of hospital emergency departments has contributed to challenges to providing high-quality care, specifically care that is safe, efficient and effective. These challenges are magnified by trends in CT utilization with uncertain implications for care delivery. The utility of CT poses challenges to the pediatric emergency medicine physician to balance risk with potential benefit. We describe the process of evidence-based clinical decision-making to define the appropriate use of CT studies. Strategies for minimizing CT utilization in managing appendicitis, traumatic brain injury and cervical spine injuries are described. Clinical scores, clinical decision rules and evidence-based guidelines can assist the clinician in providing high-quality care through effective utilization of CT.

National trends in use of computed tomography in the emergency department

STUDY OBJECTIVE

The role of computed tomography (CT) in acute illnesses has increased substantially in recent years; however, little is known about how CT use in the emergency department (ED) has changed over time.

METHODS

A retrospective study was performed with the 1996 to 2007 National Hospital Ambulatory Medical Care Survey, a large nationwide survey of ED services. We assessed changes during this period in CT use during an ED visit, CT use for specific ED presenting complaints, and disposition after CT use. Main outcomes were presented as adjusted risk ratios (RRs).

RESULTS

Data from 368,680 patient visits during the 12-year period yielded results for an estimated 1.29 billion weighted ED encounters, among which an estimated 97.1 million (7.5%) patients received at least one CT. Overall, CT use during ED visits increased 330%, from 3.2% of encounters (95% confidence interval [CI] 2.9% to 3.6%) in 1996 to 13.9% (95% CI 12.8% to 14.9%) in 2007. Among the 20 most common complaints presenting to the ED, there was universal increase in CT use. Rates of growth were highest for abdominal pain (adjusted RR comparing 2007 to 1996=9.97; 95% CI 7.47 to 12.02), flank pain (adjusted RR 9.24; 95% CI 6.22 to 11.51), chest pain (adjusted RR 5.54; 95% CI 3.75 to 7.53), and shortness of breath (adjusted RR 5.28; 95% CI 2.76 to 8.34). In multivariable modeling, the likelihood of admission or transfer after a CT scan decreased over the years but has leveled off more recently (adjusted RR comparing admission or transfer after CT in 2007 to 1996=0.42; 95% CI 0.32 to 0.55).

CONCLUSION

CT use in the ED has increased significantly in recent years across a broad range of presenting complaints. The increase has been associated with a decline in admissions or transfers after CT use, although this effect has stabilized more recently.

[X-ray in trauma and orthopedic surgery. Physical and biological impact, reasonable use, and radiation protection in the operating room]

Orthopedic and especially trauma surgeons' use of x-rays during operations vary extensively, especially in minimally invasive osteosynthesis procedures. Radiation hazards often are neglected. In this paper, a short overview of physical and biological effects of radiation are given. In addition, practical information about how to lower radiation exposure in the daily work in the operating room (OR) is given. The operating team is exposed mainly to scattered radiation. The radiation exposure is 10 times higher on the tube side than on the amplifier side. The distance between tube and surgeon must be as great as possible. The tube should be positioned under the OR table, and the distance between tube and patient should be as short as possible. The positioning of the C-arm device without radiation is important. The use of patient landmarks is used to position the C-arm over the region of interest, but the preoperative training of surgeons and team with virtual learning tools, e.g., virtX, is very effective in reducing radiation hazards.

Radiation Trends in Trauma Patients

Today, computed tomography (CT) and other studies are used more often early in a trauma case than X-rays, exposing patients to more radiation. The long-term effects of radiation exposure (RE) in trauma patients are of great concern. Investigators randomly selected 60 patients (injury severity scores 15-25) each from the years 2000, 2003, and 2006. The cumulative effective dose (CED) was calculated from the RE of all X-rays and CTs performed during the patient's hospital stay. Total CED/patient increased from 15.97 (2000) to 16.67 (2003) to 23.27 mSv (2006); the increase from 2000 to 2006 was significant ( P < 0.05). X-rays increased over the 6-year period from 9.6/patient (pt) to 11.4/pt to 15.4/pt. CT scans increased from 2.2/pt (15.19 mSv) to 3.5/pt (21.85 mSv, P < 0.05). The CED in children increased: 12.88 versus 13.17 versus 15.32 mSv/pt ( P > 0.05). RE was 19.5 versus 22.0 versus 27.1 mSv in 16 to 45-year-olds compared with 15.5 versus 14.3 versus 27.0 mSv in older adults. Sixteen to 45-year-olds had significantly higher RE than children ( P < 0.05). RE in the first hour and first 24 hours increased but not significantly ( P > 0.05). CED increased from 2000 to 2006, due primarily from CT scans. Children had no significant CED increase during the same period and had lower RE than 16 to 45-year-old adults.

Ability of a chest X-ray and an abdominal computed tomography scan to identify traumatic thoracic injury

OBJECTIVE

Our objective was to show that a chest X-ray (CXR) and an abdominal computed tomography (CT) scan are sufficient to identify most clinically significant thoracic injuries in trauma patients, rendering the thoracic CT scan useful in only a subset of patients.

METHODS

A retrospective study identified thoracic injuries in 374 trauma patients evaluated with a CXR, a thoracic CT scan, and an abdominal CT scan. Injuries seen on the initial CXR versus those seen on a CT scan only (occult) were identified and assessed for clinical relevance.

RESULTS

An abdominal CT scan identified 65% (15/23) of occult pneumothoraces, 100% (25/25) of occult hemothoraces, 64% (18/28) of occult pulmonary contusions, and 58% (18/31) of occult rib fractures. No occult pneumothoraces seen on the thoracic CT scan alone required tube thoracostomy.

CONCLUSIONS

Our pilot study suggests that a CXR and an abdominal CT scan will identify most occult intrathoracic injuries. Reserving a thoracic CT scan for patients with an abnormal CXR or high-risk mechanism could safely reduce cost and radiation exposure while still diagnosing significant thoracic injuries.