Implications of the Pan Scan in Blunt Trauma
Author: Christine B. Irish, MD, FACEP, Director of Emergency Ultrasound, Department of Emergency Medicine, Maine Medical Center, Portland, ME
Peer Reviewer: Steven M. Winograd, MD, FACEP, Attending Physician, Emergency Department, Saint Joseph's Medical Center, Yonkers, NY
Introduction
Computed tomography (CT) imaging has been extremely valuable in the evaluation of blunt trauma patients, rapidly and reliably diagnosing life-threatening traumatic injuries. Recently there has been increased usage of whole body imaging for trauma patients at many Level 1 trauma centers around the country.1,2 Whole-body imaging consists of a five-part series, including CT of the head, neck, chest, abdomen, and pelvis, and is commonly referred to as the "pan scan."
The risks and benefits associated with the pan scan have generated significant discussion in the medical community as the role of whole body imaging has become more expansive. Multiple studies support the use of liberal CT imaging in trauma patients with altered mental status or with clinical signs and symptoms of injury and these are commonly accepted indications for a pan scan.2-4 However, there is also recent trauma literature that supports the use of the pan scan in blunt trauma patients with no obvious signs of injury.5 The ability to essentially exclude any significant injury early in the course of evaluation, is a powerful motivator, but may not justify the risks of increased radiation exposure and significant costs associated with the five-part CT scan. This article will discuss the use of CT imaging in trauma patients and risks and benefits such as radiation exposure, hospital admissions, and medical costs.
How Much and How Often: CT Imaging in Trauma Patients
Source: Rizzo AG, et al. Prospective assessment of the value of computed tomography for trauma. J Trauma 1995;38:338-343.
The study by Rizzo and colleagues was a prospective assessment of the use of CT scanning early in the management of trauma patients. All trauma patients who presented to the study site during the 12-month study period and who received a CT scan within 12 hours of arrival were enrolled. Medical records were reviewed and attending surgeons were interviewed to determine whether the CT scan improved patient care. The study also evaluated morbidity related to the CT scan.
Rizzo et al enrolled 1,609 trauma patients who received 2,047 CT scans. Sixteen percent of patients had more than one CT scan. Seven-hundred and seventy (38%) scans were positive, but 225 (29%) of the positive scans did not impact patient care. Ultimately, only 29% of the CT scans that were ordered (either positive or negative) were helpful in the clinical care of the patient. The authors concluded that although a large number of CT scans were being performed, only a small percentage assisted in the actual treatment of patients.
Comment
This study by Rizzo et al attempts to quantify the utilization of CT among all trauma patients who presented to a Level 1 trauma center during the study period. As previously noted, the CT was positive in 38% patients, with 6% of these studies ultimately deemed to be false positives. The authors concluded that only 29% of all CT scans seemed to affect the clinical decision process. They also concluded that 11% of scans were unnecessary because the results were already known by other diagnostic means or clinical exam.
The authors identified several disadvantages to CT imaging, including long wait times and risk of a delay in definitive care. At their busy trauma center, the wait for abdominal CT imaging ranged from two hours to 19 hours, suggesting that serial exams may have decreased the need for scans in those patients who waited the longest for their studies. The authors also noted that the cost of CT was considerable, even when compared to admission costs. Rizzo estimated the following costs for CT imaging: CT head, $631; CT spine, $957 to $1,037; and CT of the abdomen, $988 to $1,053. During the study period, their facility's daily room charge was $1,600. There was also risk associated with treatment delay inherent to obtaining a scan. The authors noted that two patients died in the CT suite and six patients died shortly after their CT scans were completed. They stated that the two deaths in the CT suite were unavoidable due to penetrating head trauma. However, the authors determined that five out of the six patients who died shortly after CT may have had preventable deaths, although the criteria for this designation were not well explained.
If physicians rely too heavily on extensive CT imaging in stable trauma patients, patients will experience longer waits, increased radiation doses, and increased costs with little identifiable benefit. If physicians under-utilize CT technology, life-threatening injuries will certainly be missed. Given this, Rizzo and colleagues call for responsible and focused CT imaging in trauma patients until clear guidelines are developed and validated. These recommendations clearly support the use of thorough history, complete physical examination, and consideration of the mechanism of injury to guide the evaluation of every trauma patient.
What is Pan Scan's Role in Stable Blunt Trauma Patients?
Source: Salim A,. et al. Whole body imaging in blunt multisystem trauma patients without obvious signs of injury. Arch Surg 2006;141: 468-475.
Salim and colleagues evaluated the use of the pan scan in hemodynamically stable blunt-trauma patients with a significant mechanism of injury. They conducted a prospective, observational study at a Level 1 academic trauma center during an 18-month period. Inclusion criteria included no visible evidence of chest or abdominal injury, stable vital signs, normal abdominal examination in neurologically intact patients, or unreliable abdominal exam due to depressed mental status or significant mechanism of injury. High-risk injury patterns included motor vehicle accident at speed greater than 35 mph, falls greater than 15 feet, automobile versus pedestrian accident, and assault, with a depressed level of consciousness. All patients received a pan scan. The primary outcome measured was change in the treatment plan as a direct result of information gained from the CT. Treatment plan changes included early discharge, admission for observation, further diagnostic tests, or operative intervention.
One thousand patients had whole-body imaging during the 18-month study period. Five-hundred and ninety-two patients (59.2%) were enrolled based on mechanism of injury. The remaining 408 patients (40.8%) received whole-body imaging based on depressed level of consciousness. Of the 592 patients enrolled due to mechanism, eight (1.3%) required laparotomy. Of the eight patients who required surgical intervention, six (1.0%) were taken to the operating room based entirely on CT findings. Four of these six patients had splenic injuries, and two had hollow viscous injuries. Clinically significant injuries were found in 3.5% of head CT scans that were ordered based on mechanism, including subarachnoid hemorrhage, cerebral contusion, and subdural hematoma. Of the cervical spine CT scans ordered based on mechanism, 5.1% were abnormal, as were 19.6% of chest CT scans and 7.1% of abdominal CT scans. Treatment was changed in 18.9% of patients based solely on an abnormal CT scan result. The authors concluded that the use of the pan scan based on mechanism of injury in awake, hemodynamically stable patients is warranted.
Comment
The pan scan is being used with increasing frequency at trauma centers around the country, but it remains debatable whether it is indicated in stable trauma patients without signs or symptoms of injury. Without question, the benefits of whole-body imaging outweigh the risks in trauma patients with altered mental status or signs of traumatic injury, and there is significant literature that supports this concept.2-4 However, the appropriateness of whole-body imaging in awake, asymptomatic blunt-trauma patients is debatable. Salim et al support a liberal CT scanning policy to allow for earlier hospital discharge. However, their conclusion is limited by several flaws that should be noted before widespread use of the pan scan in stable, asymptomatic blunt-trauma patients is recommended.
The authors conclude that 18.9% of patients had changes in their treatment plans secondary to an abnormal CT scan. However, this percentage included all 1,000 patients who had a pan scan, not just the 592 patients who had CT imaging based solely on mechanism. Comparison of the mechanism-only group of alert patients with reliable physical examination to the altered-mental-status group of 408 patients with unreliable physical examinations is not appropriate. The change in treatment plans for the mechanism-only study group is not specified. Instead, the authors highlighted the incidence of injuries that were identified by CT in each subset (3.5% head, 5.1% neck, 19.6% chest, 7.1% abdominal) as further support for liberal CT imaging. Unfortunately, the authors admit that the patients in the mechanism-only group were not actually palpated for mid-line cervical spine tenderness or thoracic wall tenderness, but were only visually inspected for outward signs of injury. This approach omits a major component of the evaluation of the cervical spine-point tenderness, which has been previously validated and is used in major trauma centers around the country.6 The study results also do not justify liberal pan scanning to prevent delay in diagnosis of hollow viscous injuries, since the data suggest an extremely low rate of disease. Only eight patients out of 1,000 (0.8%) were actually diagnosed with hollow viscous injury.
Another consideration is the observational study design, which limits comparisons regarding the impact of pan scan on length of stay, mortality or medical costs. The authors suggest that a future study may demonstrate reduced costs or earlier discharge. Physicians will need to carefully consider any potential cost savings or decreased hospitalization rates to determine if it justifies considerable radiation exposure for thousands of trauma patients each year. Alternatives such as serial physical exams or serial ultrasounds may also have a role in decreasing the use of the pan scan and supporting cost containment. In one study that evaluated the role of serial ultrasounds, no patient with a negative second ultrasound after four hours developed clinically significant hemoperitoneum.7 This study should not be used as justification for pan scanning stable, alert trauma patients with reliable physical exams; more research is critical.
Does CT Reduce Admission of Blunt Trauma Patients?
Source: Awasthi S, et al. Is hospital admission or observation required after a normal abdominal CT scan in children with blunt abdominal trauma? Acad Emerg Med 2008;1:895-899.
The objective of this study was to determine if hospital admission rates were decreased among pediatric trauma patients who received CT imaging in the emergency department. This study was a prospective, observational cohort study of children with blunt abdominal trauma presenting to an urban Level 1 trauma center during a 38-month period. Exclusion criteria included patients who were transferred from another facility after abdominal CT scanning and patients who sustained penetrating trauma. The patients received abdominal CT scans with intravenous contrast, and CT scans were interpreted by attending radiologists. Admission decisions were made by the attending emergency physician in consultation with pediatric trauma surgeons.
The main outcome measures were the presence of intra-abdominal injury (IAI) and the presence of IAI requiring therapeutic intervention, including blood transfusions, surgical intervention, or angiographic embolization. One thousand, two hundred ninety-five were enrolled. Two-hundred ten (16.2%) had IAI identified and 1,085 (83.8%) had normal initial CT scans. Of the 1,085 patients with normal initial CT scans, 68% were admitted to the hospital and 32% were discharged home. None of the patients discharged home with normal abdominal CT scans were subsequently diagnosed with IAI. Two of the hospitalized patients were later diagnosed with IAI. The negative predictive value of the initial abdominal CT for IAI was 99.8%, and the negative predictive value of CT scan for IAI requiring acute intervention was 100%. The authors conclude that children with blunt abdominal trauma and normal abdominal CT scans are unlikely to have IAI, and hospital admission solely for serial abdominal exams and laboratory measurements has limited utility.
Comment
Liberal whole-body imaging has been recommended by some authors to rapidly exclude traumatic injury and possibly lead to reduced admission rates and medical costs among stable trauma patients. However, there have not been any large studies that validate this argument. Research that specifically evaluates the cost of inpatient observation versus the pan scan is lacking. The study by Awasthi and colleagues is an important first step in evaluating the impact of a negative CT scan on medical costs and hospital admission policies.
As previously noted, none of the patients with normal abdominal CT scans who were discharged from the emergency department were diagnosed with IAI. Only two of the patients admitted to the hospital with normal CT scans developed IAI; one patient had a seatbelt sign and abdominal tenderness and the other was a pedestrian struck by a motor vehicle with significant pelvic fractures noted on initial evaluation. Neither patient required operative therapeutic intervention. This study suggests that improved CT technology and imaging capabilities may decrease the incidence of missed gastrointestinal and pancreatic injuries that was noted by earlier-generation CT scanners.8,9 This study complements the prospective, multi-institutional study by Livingston et al that concluded that adult trauma patients with normal abdominal CT scans can be safely discharged from the ED.2 While this study does not consider the negative predictive value of the remaining four components of a pan scan, it provides evidence that a negative abdominal CT scan in pediatric patients without other symptoms of traumatic injury may justify reduced admissions and lead to cost savings.
Pan Scan: Effective Dose and Risk of Radiation in Adults
Source: Tien HC, et al. Radiation exposure from diagnostic imaging in severely injured trauma patients. J Trauma 2007;62:151-156; and Winslow JE, et al. Quantitative assessment of diagnostic radiation doses in adult blunt trauma patients. Ann Emerg Med 2008;52:93-97.
The study by Tien and colleagues measures the dose of radiation that trauma patients receive from diagnostic imaging. This study is a prospective cohort study that was conducted over a 10-month period at a Level I trauma center in Toronto. The surface radiation dose in millisieverts (mSv) was measured by placing three dosimeters on the neck, chest, and groin of each patient at the time of arrival to the hospital. Dosimeters were removed prior to discharge. Total effective dose, as well as thyroid, breast, and red bone marrow organ doses were calculated. The mean effective dose of radiation to all trauma patients was 22.7 mSv. The authors extrapolated their data to suggest that this would result in the following excess lifetime cancer mortalities out of 100,000 patients exposed: an additional 190 overall cancer deaths, as well as 4.4 thyroid cancers, 41.4 breast cancers, and 13.3 leukemias. They also noted that the mean radiation dose to the thyroid was 58.5 mSv, with 22% of their patients receiving greater than 100 mSv of radiation to the thyroid. The authors conclude that trauma patients are exposed to significant radiation doses from their diagnostic imaging, which should be noted and considered as the use of whole-body CT imaging rapidly increases.
Winslow and colleagues attempt to quantify the amount of ionizing radiation received by adult trauma patients during the first 24 hours of their care. They noted that at the study institution, major trauma patients often received a pan scan. This was a retrospective study that collected data on 100 consecutive adult, Level 2 trauma patients, with levels of trauma adhering to the American College of Surgeon's standard trauma criteria. Total radiation doses were measured by using CT dose indexes calculated by the CT scanner for each patient and standard tables of radiation doses for plain radiography. Seventy-nine (92%) of the 86 patients had a pan scan performed. The median number of CT scans performed was three, and the median number of plain films performed was 9.5. The median dose equivalents for head CT was 3 mSv and 26 mSv for chest/abdomen/ pelvis CT. In this study, the median radiation exposure per patient was 40.2 mSv, which is the equivalent of 1,005 plain chest films. The authors conclude that the dose of 40.2 mSv could contribute to an additional 322 lethal cancers out of 100,000 patients using prediction models from the National Academies Seventh Report on biologic effects of radiation.
Comment
Trauma patients with a significant mechanism of injury often undergo extensive imaging during their initial diagnostic evaluation. Prior to the advent of helical and multi-slice CT imaging, the evaluation of these trauma patients included plain radiographs of the neck, chest, and pelvis. The non-invasive nature of CT and rapid availability of vital information has resulted in a sharp increase in the use of CT scans in trauma victims. Currently, it is not uncommon for victims of blunt trauma to undergo a pan scan. Tien and colleagues wisely questioned the public health implications of this increase in radiation exposure and designed their study to quantify the radiation doses trauma patients receive during diagnostic evaluations. After measuring the absorbed dose of radiation at the skin in three different sites, organ doses and total effective dose were calculated with a standardized computer package, CT dosimetry.
The excess mortality predictions from this study were derived from the National Council on Radiation Protection and Measurement Report 115 risk model, which calculates radiation induced cancer mortality in patients 20 to 65 years of age.10 As Tien and colleagues noted, the stochastic effect is the long-term risk of cancer induction and genetic mutations from radiation exposure. The stochastic model is commonly used in population studies that determine cancer risk, and is based on a linear relationship between dose and mutation induction. There is no clear threshold below which radiation exposure is known to be safe. It is commonly accepted that certain organs are more susceptible to cancer induction from radiation exposure, and that pediatric patients are more susceptible than adults to cancer induction from equivalent radiation exposures.11
The Tien group's results should be studied carefully. As noted previously, the stochastic model assumes a linear relationship to exposure and cancer induction, with no clear threshold for safe radiation levels. The average annual background radiation exposure to humans is 2.4 mSv. This study suggests that trauma patients are routinely subjected to radiation doses equivalent to 10 years' worth of background natural radiation exposure. This is concerning in several respects because a significant percentage of trauma patients are young adults and children. Previous research established that the risk of malignant transformation is increased with exposures in the first three decades of life and directly related to the dose of ionizing radiation received. Younger patients have a smaller body mass to shield their organs from the radiation dose and also have a longer lifetime during which they may express their induced genetic mutations. The implications of this significant radiation multiply when considering all the trauma patients who receive pan scans each year. While the risks to one individual may be quite small, the risks quickly multiply for the trauma population as a whole.
This study has several limitations, most obvious being its setting at an adult trauma center. Because the study did not include pediatrics, the results should not be applied to the pediatric population, which is inherently more susceptible to radiation exposure. The cancer risk model that was used to calculate lifetime excess cancer mortality is based upon dosages obtained from a large, single exposure, as compared to radiation exposure over the course of several weeks, as is common during hospitalization. Finally, the study patients had significantly higher injury severity scores (ISS) than did non-study trauma patients, which may also limit application of the study results to all trauma patients.
Winslow and colleagues evaluated the amount of ionizing radiation received by adult trauma patients, 92% of whom underwent a pan scan, in their first 24 hours of hospitalization. This is in contrast to the study by Tien et al that evaluated the effective radiation dose in adult trauma patients during their entire hospitalization. The median dose of ionizing radiation per patient was 40.2 mSv. When considered in isolation, this dose is unlikely to contribute significant morbidity to the individual patient. When applied to blunt trauma patients at a national level, the results guarantee that some patients will develop lethal malignancies as a direct consequence of their radiation exposure.
How can we identify patients at highest risk? There is significant evidence that age at the time of exposure, total radiation dose and which organs are radiated are leading risk factors in prediction models of lethal transformation.11 Current estimates indicate that a single CT scan will result in a lethal malignancy in one of every 3,000 adult patients and one in every 500 pediatric patients.12
This study has several limitations. The study was a retrospective analysis and the data could be limited by missing data or abstraction errors. The authors also propose a multicenter study to minimize discrepancies from differences in regional or national practice patterns. The authors used CT dose indexes to estimate effective radiation dose. As they noted, this is one accepted technique for dose estimation, but it is possible that other methods could be more accurate. Despite the limitations, this study is vitally important in its recommendations to be judicious and discriminating with the pan scan in trauma patients. While CT imaging has the power to identify serious occult injuries, it also has the ability to be hazardous to patients and should be ordered with careful consideration.
Risk and Effective Radiation Dose in Pediatric Patients
Source: Kim PK, et als. Effective radiation dose from radiology studies in pediatric trauma patients. World J Surg 2005;29:1557-1562.
The authors sought to evaluate the total effective radiation dose in pediatric trauma patients given that children are more susceptible than adults to the lifetime risks of cancer induction after equivalent radiation exposures. The study was a retrospective chart review and enrolled 394 children at a Level 1 pediatric trauma center. Head CT was the most common radiologic study performed, followed by plain films of the neck and chest, as well as CT of the abdomen and pelvis. The total number and type of study per patient was determined and the effective radiation dose per patient was calculated using standardized tables of age-adjusted expected radiation doses. The calculated mean effective radiation dose per patient was 14.9 mSv, with CT accounting for almost all (97.5%) of the effective radiation dose received per patient. This study found that pediatric trauma patients were exposed to radiation levels four times greater than the annual background radiation dose for an average North American The authors concluded that whenever possible, clinicians should adhere to a policy of radiation doses "as low as reasonably achievable" for pediatric patients.
Comment
This important study attempts to quantify the typical radiation dose received by pediatric trauma patients during their evaluation and hospitalization. The authors concluded that the mean effective radiation dose in pediatric patients was 14.9 mSv. The effect of this radiation is significant given that there is no defined safe level of ionizing radiation. The study has several limitations that must be considered as the results are discussed. The calculated effective radiation doses were not measured doses, but expected doses for each study type obtained from age-adjusted tables. These calculations could either under- or overestimate the total effective dose depending on institutional policies that regulate CT settings. This might limit the accuracy of these results at other institutions.
Despite these limitations, the authors correctly identify the increased risk of radiation exposure in pediatric trauma patients. Compared to adults, children have higher lifetime risks of lethal malignant transformation with equivalent doses of radiation.11 This finding is supported by two principles. First, children are inherently more susceptible to radiation exposure than adults, with higher rates of leukemia and solid organ cancers following exposures.12 With equivalent radiation exposures, the effective dose can be 50% higher in pediatric patients due to their smaller body habitus and decreased tissue attenuation.14 Pediatric patients also have a longer life expectancy during which they may express radiation-induced mutations. Until recently, most risk models for radiation exposure centered on adult patients. However, through significant research by Brenner and others, much progress has been made in estimating radiation-induced fatal malignancy in pediatric CT examinations.11,14 Current estimates indicate that of the 600,000 pediatric abdominal and head CTs performed annually in the United States, 500 patients may die of cancer from the CT radiation.13 It is imperative that these statistics be considered as we integrate whole-body imaging into the care of our youngest trauma patients.
Physician and Patient Perception of Radiation Dose, Risk
Source: Lee CI, et al. Diagnostic CT scans: Assessment of patient, physician, and radiologist awareness of radiation dose and possible risks. Radiology 2004;231:393-398.
Lee and colleagues attempt to determine the awareness of radiation dose and risks of CT imaging among patients and two different groups of providers-emergency physicians and radiologists. Study subjects included all emergency physicians and radiologists in both departments at a tertiary care, academic medical center in the United States. In addition, adult patients who received an abdominal or pelvic CT during a pre-defined 14-day period at this same medical center were also enrolled.
All study subjects completed a study survey and the effective radiation dose for each patient was estimated using dosing information from the CT scanner. Seventy-six patients, 45 emergency physicians, and 38 radiologists were enrolled in the study. Patients were asked if the risks, benefits, and radiation dose from their CT scan had been discussed, and were also asked if they believed that their lifetime risk of cancer was increased after completion of the CT scan. Emergency physicians and radiologists were asked similar questions.
This study found that only 7% of patients were informed of risks and benefits of their CT scan, compared to 22% of emergency physicians who reported providing informed consent. Forty-seven percent of radiologists believed that the risk of cancer was increased after one abdominal or pelvic CT, compared to 9% of emergency physicians and 3% of patients. None of the groups of study subjects correctly estimated the effective radiation dose from the CT scan. The authors conclude that patients at the study institution did not appear to be informed of the risks and benefits of their CT scan, and that physicians and patients alike could not accurately predict the radiation dose from this single scan.
Comment
The trend towards the pan scan is not an isolated phenomenon in the care of trauma patients; in all medical specialties, CT imaging has rapidly expanded. However, this access to crucial information is not without risk. There are estimates that new-generation CT scanners expose patients to as much as 40% more absorbed radiation doses than previous technology.15 While it is clear that the amount of effective radiation from CT scans is much higher than other conventional diagnostic radiology, the long-term implications of this additional radiation exposure remains uncertain. It is critical that providers understand the true risks and benefits of CT imaging and are able to accurately communicate this information to their patients.
The current study by Lee et al indicates that physicians' knowledge of radiation dose and lifetime cancer risk is variable and often simply incorrect. Physicians were also unable to clearly communicate radiation risks to patients in an effective manner. Physicians reported discussing risks 20% of the time; unfortunately, patients report discussing risks with their physicians in fewer than 10% of cases. This discrepancy is not a new challenge for providers, who often struggle to accurately and clearly convey complex medical information to patients. This study reinforces the fact that physicians do not always obtain or provide adequate informed consent. Certainly, the inaccuracies held by physicians regarding radiation dose and cancer risks contribute to the difficulty noted in physician and patient communication.
Conclusion
It has been widely speculated that Marie Curie's death at the age of 67 was a consequence of lifelong radiation exposure caused by the very same elements that brought her two Nobel prizes. The largest source of radiation exposure to patients is from CT scans obtained for diagnostic purposes.5 Blunt trauma patients bear a significant burden of this radiation exposure, as extensive CT imaging may quickly rule out life-threatening injuries and enable early discharge from medical care.
Until recently, there has been limited discussion of the impact of this increase in CT imaging. With the evolution of the pan scan in trauma medicine, the debate over radiation risks has reignited. The lifetime probability of a man dying from cancer is 23% and for a woman the probability is 20%, so it would be easy to question the significance of a very small increase in these probabilities.16 Furthermore, given the limited research and abstract nature of the radiation risk, it would be easy to bury our concerns and forge ahead with liberal whole-body imaging in search of traumatic injuries. This would be the wrong decision. It is imperative that physicians provide their patients the same consideration and risk reduction that they provide themselves every time they don a protective lead gown or step out of the room during a portable radiograph. The incorporation of protective measures into CT guidelines, such as adjusting parameters based on body size and enforcing strict shielding practices, could reduce the effective radiation dose of pan scans.11 Certainly, a more effective approach would be to support and encourage research on delineating appropriate indications and utilization approached for CT scanning in both the adult and pediatric population.
References
1. Winslow JE, et al. Quantitative assessment of diagnostic radiation doses in adult blunt trauma patients. Ann Emerg Med 2008;52:93-97.
2. Livingston DH, et al. Admission or observation is not necessary after a negative abdominal computed tomographic scan in patients with supsected blunt abdominal trauma: Results of a prospective, multi-instutional trial. J Trauma 1998;44:273-282.
3. Self ML, et al. The benefit of routine thoracic, abdominal and pelvic computed tomography to evaluate trauma patients with closed head injury. Am J Surg 2003;186:609-614.
4. Beaver BL, et al. The efficacy of computed tomography in evaluating abdominal injuries in children with major head trauma. J Pediatr Surg 1987;22:1117-1122.
5. Mettler FA, et al. CT scanning: Patterns of use and dose. J Radiol Prot 2000;20:353-359.
6. Hoffman JR, et al. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. N Eng J Med 2000;343:94-99.
7. Blackbourne LH, et al. Secondary ultrasound examination increases the sensitivity of the FAST exam in blunt trauma. J Trauma 2004;57:934-938.
8. Akhrass R, et al. Computed tomography: An unreliable indicator of pancreatic trauma. Am Surg 1996;62:647-651.
9. Ilahi O, et al. Efficacy of computed tomography in the diagnosis of pancreatic injury in adult blunt trauma patients: A single institutional study. Am Surg 2002;68:704-708.
10. NCRP Report No 115. Risk Estimates for Radiation Protection. Bethesda, MD: National Council on Radiation Protection and Measurements, 1993.
11. Brenner DJ, et al. Computed tomography-An increasing source of radiation exposure. N Eng J Med 2007;357: 2277-2284.
12. Brenner DJ, et al. Estimated radiation risks potentially associated with full-body CT screening. Radiology 2004; 232:735-738.
13. Wakeford R. The cancer epidemiology of radiation. Oncogene 2004;23: 6404-6428.
14. Chodick G, et al. Excess lifetime cancer mortality risk attributable to radiation exposure from computed tomography examinations in children. IMAJ 2007; 9:584-587.
15. Golding SJ, et al. Commentary. Radiation dose in CT: Are we meeting the challenge? Br J Radiol 2002;75:1-4.
16. Tien HC, et al. Radiation exposure from diagnostic imaging in severely injured trauma patients. J Trauma 2007;62:151-156.
Computed tomography (CT) imaging has been extremely valuable in the evaluation of blunt trauma patients, rapidly and reliably diagnosing life-threatening traumatic injuries. Recently there has been increased usage of whole body imaging for trauma patients at many Level 1 trauma centers around the country.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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