Pelvic CT Imaging in Blunt Abdominal Trauma
Status: | Completed |
---|---|
Conditions: | Hospital |
Therapuetic Areas: | Other |
Healthy: | No |
Age Range: | 3 - 60 |
Updated: | 4/21/2016 |
Start Date: | February 2013 |
End Date: | March 2015 |
Pelvic CT Imaging in Blunt Trauma: Limiting Low Yield Radiation Exposure in Carefully Selected Adult and Pediatric Patients
Abdominopelvic CT (CTap) utilization rose significantly in blunt trauma patients over the
last decade. However, the observed increases failed to reduce mortality or missed injury
rates. Several investigators have derived (citation) and validated (citation) clinical
decision rules that attempt to identify a subset of low risk pediatric and adult patients in
whom abdominopelvic CT imaging can be safely eliminated. Thus far these efforts failed to
significantly reduce utilization. The investigators propose an alternative and complimentary
strategy to decrease radiation by selectively eliminating the pelvic imaging portion of the
abdominopelvic CT in low risk patients. In stable, alert patients without clinically
evidence of pelvis or hip fractures, abdominal CT imaging alone (diaphragm to iliac crest)
identifies clinically significant intra-abdominal injury (cs-IAI) as accurately as routine
abdominopelvic imaging (diaphragm to greater trochanter) and results in a clinically
important decrease in radiation exposure. The study will investigate this by comparing the
accuracy of an imaging protocol using CT abdomen alone versus CT abdomen and pelvis to
detect cs-IAI among stable, blunt trauma patients without suspected pelvis or hip fractures
in two age groups: ages 3-17 years and 18-60. Patients will undergo CT imaging as deemed
clinically indicated by the treating clinician. Among those who have abdominopelvic CT
scans, the study will determine the test characteristics of CT abdomen alone versus CT
abdomen plus CT pelvis imaging for the identification of cs-IAI. The reference standard will
include initial radiology reports, with structured follow up of indeterminate scans,
operative reports, and 7-day medical record review.
last decade. However, the observed increases failed to reduce mortality or missed injury
rates. Several investigators have derived (citation) and validated (citation) clinical
decision rules that attempt to identify a subset of low risk pediatric and adult patients in
whom abdominopelvic CT imaging can be safely eliminated. Thus far these efforts failed to
significantly reduce utilization. The investigators propose an alternative and complimentary
strategy to decrease radiation by selectively eliminating the pelvic imaging portion of the
abdominopelvic CT in low risk patients. In stable, alert patients without clinically
evidence of pelvis or hip fractures, abdominal CT imaging alone (diaphragm to iliac crest)
identifies clinically significant intra-abdominal injury (cs-IAI) as accurately as routine
abdominopelvic imaging (diaphragm to greater trochanter) and results in a clinically
important decrease in radiation exposure. The study will investigate this by comparing the
accuracy of an imaging protocol using CT abdomen alone versus CT abdomen and pelvis to
detect cs-IAI among stable, blunt trauma patients without suspected pelvis or hip fractures
in two age groups: ages 3-17 years and 18-60. Patients will undergo CT imaging as deemed
clinically indicated by the treating clinician. Among those who have abdominopelvic CT
scans, the study will determine the test characteristics of CT abdomen alone versus CT
abdomen plus CT pelvis imaging for the identification of cs-IAI. The reference standard will
include initial radiology reports, with structured follow up of indeterminate scans,
operative reports, and 7-day medical record review.
Abdominopelvic computed tomography (CTap) utilization rose significantly in blunt trauma
patients over the last decade but failed to reduce mortality or missed injury rates.
Primary Hypothesis: In stable, alert patients (GCS > 14) without clinically evident
fractures of the pelvis, hip or lumbar spine, CT abdomen (CTa) alone (diaphragm to iliac
crest) identifies intra-abdominal injury (IAI) with an accuracy that is not inferior to
routine CTap (diaphragm to greater trochanter) with a clinically relevant reduction in
radiation exposure.
Primary Aim: Compare the accuracy of CTa alone versus CTap to detect IAI in two age groups:
ages 3-17 years and 18-60 years. Blunt trauma patients requiring CTap will be enrolled. Data
obtained prior to CT imaging include demographics, injury mechanism, exam and pelvic
radiograph findings and FAST results from the trauma evaluation. The original CTap will be
digitally reformatted to create matched pairs of de-identified CTa and CTap studies. A board
certified study radiologist, blinded to the original CT and clinical outcome, will interpret
the CTa studies in injured patients. McNemar's chi-square test will be used to evaluate the
null hypothesis for injuries in matched pairs assuming no difference for uninjured patients.
Te the test characteristics of the CTa versus CTap will be determined. The reference
standard will include initial radiology reports, operative reports, and 7-day medical record
review. If the upper limit of the 95% confidence interval for the difference in the
performance (accuracy) of CTap and CTa alone is less than 3%, the conclusion will be that
CTa alone is not inferior to CTap to diagnose IAI. Secondary Aims: The mean effective doses
of radiation will be calculated and compared with reductions up to 50% expected. The study
will determine if physicians' pretest probability accurately identifies clinically
significant pelvis, hip and lumbar spine fractures (CTp indications) in two age groups: ages
3-17 years and 18-60 years. Using a gestalt pretest probability of ≤ 2% as "negative for
injury", and a pretest probability > 2% as "positive for injury", the test characteristics
of physician estimation will be determined. The test characteristics and interobserver
agreement (Cohen's kappa statistic) of exam findings expected to predict fractures of the
pelvis, hip and lumbar spine will be reported separately.
patients over the last decade but failed to reduce mortality or missed injury rates.
Primary Hypothesis: In stable, alert patients (GCS > 14) without clinically evident
fractures of the pelvis, hip or lumbar spine, CT abdomen (CTa) alone (diaphragm to iliac
crest) identifies intra-abdominal injury (IAI) with an accuracy that is not inferior to
routine CTap (diaphragm to greater trochanter) with a clinically relevant reduction in
radiation exposure.
Primary Aim: Compare the accuracy of CTa alone versus CTap to detect IAI in two age groups:
ages 3-17 years and 18-60 years. Blunt trauma patients requiring CTap will be enrolled. Data
obtained prior to CT imaging include demographics, injury mechanism, exam and pelvic
radiograph findings and FAST results from the trauma evaluation. The original CTap will be
digitally reformatted to create matched pairs of de-identified CTa and CTap studies. A board
certified study radiologist, blinded to the original CT and clinical outcome, will interpret
the CTa studies in injured patients. McNemar's chi-square test will be used to evaluate the
null hypothesis for injuries in matched pairs assuming no difference for uninjured patients.
Te the test characteristics of the CTa versus CTap will be determined. The reference
standard will include initial radiology reports, operative reports, and 7-day medical record
review. If the upper limit of the 95% confidence interval for the difference in the
performance (accuracy) of CTap and CTa alone is less than 3%, the conclusion will be that
CTa alone is not inferior to CTap to diagnose IAI. Secondary Aims: The mean effective doses
of radiation will be calculated and compared with reductions up to 50% expected. The study
will determine if physicians' pretest probability accurately identifies clinically
significant pelvis, hip and lumbar spine fractures (CTp indications) in two age groups: ages
3-17 years and 18-60 years. Using a gestalt pretest probability of ≤ 2% as "negative for
injury", and a pretest probability > 2% as "positive for injury", the test characteristics
of physician estimation will be determined. The test characteristics and interobserver
agreement (Cohen's kappa statistic) of exam findings expected to predict fractures of the
pelvis, hip and lumbar spine will be reported separately.
Inclusion Criteria:
1. 3-60 years of age evaluated for blunt trauma with a GCS of >14
2. Order of CT abdomen and pelvis imaging
Exclusion Criteria:
1. Patients requiring intubation or suspected neurological injury (defined above)
2. Pregnant patients
3. Intoxicated patients
4. Patients with age defined hypotension
5. Exploratory laparotomy or transfusion during the ED evaluation
6. Non-verbal patients
7. Positive FAST exam
8. Patients with abdominal trauma or surgery in the last month
9. Victims of sexual assault or non-accidental trauma (NAT)
10. Patients with known or suspected fractures of the femur or pelvis prior to CT imaging
11. Patients with hip dislocations
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