Note: This guideline has been updated. The National Guideline Clearinghouse (NGC) is working to update this summary.

Blunt abdominal trauma

To evaluate the appropriateness of initial radiologic examinations for adults with blunt abdominal trauma

Adults with blunt abdominal trauma

Note: Penetrating trauma and pediatric cases are not considered.

Utility of radiologic examinations in diagnosis of blunt abdominal trauma

Literature Search Procedure

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the American College of Radiology Appropriateness Criteria (ACR AC) topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis, and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid, but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the ACR Appropriateness Criteria® Evidence Table Development document (see "Availability of Companion Documents" field).

Modified Delphi Technique

When the data available from existing scientific studies are insufficient, the American College of Radiology Appropriateness Criteria (ACR AC) employs systematic consensus techniques to determine appropriateness. The ACR AC panels use a modified Delphi technique to determine the rating for a specific procedure. A series of surveys are conducted to elicit each individual panelist's expert opinion of the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario based on the available data. ACR staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. Voting surveys are completed by panelists without consulting other panelists. The ratings are integers on a scale between 1 and 9, where 1 means the panel member feels the procedure is "least appropriate" and 9 means the panel member feels the procedure is "most appropriate." Each panel member has one vote per round to assign a rating. The surveys are collected and de-identified and the results are tabulated and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized, and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. If eighty percent (80%) of the panel members agree on a single rating or one of two consecutive ratings, the final rating is determined by the rating that is closest to the median of all the ratings. Up to three voting rounds are conducted to achieve consensus.

If consensus is not reached through the modified Delphi technique, the panel is convened by conference call. The strengths and weaknesses of each imaging examination or procedure are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

Note: This guideline has been updated. The National Guideline Clearinghouse (NGC) is working to update this summary. The recommendations that follow are based on the previous version of the guideline.

Note from the American College of Radiology (ACR) and the National Guideline Clearinghouse (NGC): ACR has updated its Relative Radiation Level categories and Rating Scale. The Rating Scale now includes categories (1,2,3 = Usually not appropriate; 4,5,6 = May be appropriate; 7,8,9 = Usually appropriate). See the original guideline document for details.

ACR Appropriateness Criteria®

Clinical Condition: Blunt Abdominal Trauma

Variant 1: Unstable patient.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 2: Stable patient.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 3: Hematuria >35 red blood cells (RBC)/high power field (HPF) (stable).

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

This review covers only the issue of blunt abdominal trauma in adults. Penetrating trauma and pediatric cases are not considered. A continued trend is noted in which imaging is used less for mere detecting intraperitoneal fluid (which correlates with injury but does not predict the need for therapeutic surgery) and more for detection of specific findings that do predict the need for therapeutic surgery or for angiographic embolization or that predict the need for a period of close observation for an injured patient. This trend in imaging parallels a strong trend in trauma therapy toward nonoperative management of injuries of the spleen, liver, and kidney even when hemoperitoneum is present. This new approach decreases the frequency of nontherapeutic surgery.

Category A

Hemodynamically unstable patients presenting to the emergency room with clinically obvious major abdominal trauma and with unresponsive profound hypotension need rapid clinical evaluation and immediate resuscitation with volume replacement. If such unstable patients do not respond to resuscitation (become hemodynamically stable), and if they have clear clinical evidence of abdominal injury, they should go immediately to the operating room without imaging. During resuscitative efforts, if time and circumstances permit, conventional radiographs of the chest and abdomen are often obtained as part of trauma protocols. This may help identify a pneumothorax, pneumoperitoneum, or significant bone injury. Ultrasound (US) performed by an experienced sonologist to check for intraperitoneal free fluid may quickly provide information that can support a decision to operate immediately, with the caveat that the false negative rate is at least 15%. More detailed US to check for organ injury takes too long in this setting and suffers from poor sensitivity. There is now general agreement that routine diagnostic peritoneal lavage (DPL) is obsolete because of its invasive nature, lack of specificity, and inability to predict the need for therapeutic surgery. Those patients for whom emergency department resuscitation is successful can be evaluated by contrast-enhanced computed tomography (CT) before surgery. In those patients who cannot be stabilized with fluid and/or pharmacologic intervention, surgery should generally not be delayed by imaging. If the patient becomes hemodynamically stable after surgical intervention, CT scanning with intravenous (IV) contrast should be performed to identify other potential injuries not identified during surgery.

Category B

Hemodynamically stable patients, patients with mild to moderate responsive hypotension presenting to the emergency room after blunt abdominal trauma, and unstable patients who stabilize after initial resuscitation are in a separate category. They typically have a history of significant trauma and have at least moderate suspicion of intra-abdominal injury based on clinical signs and symptoms. For these patients, two decisions need to be made: 1) Is urgent therapeutic surgery or angiography (invasive therapy) needed? 2) If not, is a period of close observation warranted? If CT is to be performed, radiographs will offer little if any incremental help with those questions. Rather, the decision to proceed with urgent surgery depends on the identification of specific CT criteria (e.g., active hemorrhage, parenchymal blush or pseudoaneurysm in the spleen, perforation of a hollow viscus, or disruption of the pancreas and or pancreatic duct). The decision to operate urgently does not solely depend on the identification of hemoperitoneum or the identification of parenchymal injury to the liver or spleen, because most patients in this category ultimately do not need surgery. However, accurate identification of hemoperitoneum or organ injury is important because patients with these findings require at least a period of close observation. Patients with multiple organ injury or significant active bleeding may require invasive therapy, even if they are hemodynamically stable. Conversely, stable patients with isolated organ injury may not need surgery or may need only angiography with embolization even with a large amount of hemoperitoneum.

At this point, US is not a good modality for imaging evaluation because it misses up to 25% of liver and spleen injuries, most renal injuries, and virtually all pancreatic, mesenteric, and gut injuries. Studies have shown that US is quite insensitive in detecting organ injury: it missed 62% of spleen and 14% of liver injuries that were found by CT and surgery. It also misses a high proportion of retroperitoneal hemorrhage and of bladder rupture. Combining the results for US in 1,535 abdominal trauma patients from eight published series yields an average US sensitivity of 88% for hemoperitoneum and 74% for organ injury. Unfortunately, a negative US (absence of hemoperitoneum) does not rule out significant organ or viscus injury that might require invasive therapy or observation.

US is also insensitive to perforation of gut and to pancreatic injury. For these reasons, it is not very useful in deciding when a patient needs urgent surgery or angiography. For the same reasons, US is not an accurate modality to determine whether a patient needs a period of close observation; thus, if a negative US is the sole imaging modality used to triage a patient, for safety reasons it must be followed by a 12- to 24-hour period of in-hospital observation. It should be noted that 96% of trauma centers perform fewer than two trauma US exams per month, so there is currently little national experience with or teaching of trauma US.

Although US is 63% sensitive to moderate amounts of free intraperitoneal fluid (compared with CT), 400 to 600 cc are needed for US detection of fluid in the trauma setting. Almost regardless of volume, a US diagnosis of free fluid alone does not predict that surgery is needed or that surgery will be therapeutic. In addition, in the best of hands, there is at least a 15% false negative rate for detecting hemoperitoneum with US. US poorly identifies active hemorrhage and also does not accurately predict the need for surgery in splenic injuries.

In hemodynamically stable patients (category B trauma patients), CT accurately predicts whether invasive therapy is urgently needed by identifying active hemorrhage, or hepatobiliary, splenic (either parenchymal contrast blush or pseudoaneurysm), pancreatic, genitourinary, intestinal, or diaphragmatic injury. For these reasons, CT is the primary imaging modality for deciding whether a patient needs urgent surgery, therapeutic angiography, or close observation.

The trend toward placing multidetector CT (MDCT) scanners close to or in emergency departments has substantially diminished the delay in getting patients to the CT scanner and has decreased actual scan time to less than 40 seconds. In nearly all circumstances, results from MDCT of the abdomen and pelvis can be obtained faster than results from a detailed US of the abdomen or pelvis. In most cases, patient turnaround with rapid-process MDCT can be less than 10 minutes for a trauma patient.

The radiologist should carefully examine images on the picture archiving and communication system (PACS), or at the CT console, where images can be altered to identify bone injury, pneumoperitoneum, or subtle organ injury. Particular care should be taken to find injury of the spleen because these patients may need observation for potential delayed hemorrhage. In some instances, stable patients with more severe injuries of the liver or spleen plus hemoperitoneum may be managed conservatively with close observation only. It should be noted, however, that various schemes for using CT to grade liver or spleen lacerations are not helpful in deciding whether a patient needs surgery. This decision must be based on the clinical status of the patient in combination with the image findings. If evidence of active hemorrhage is discovered on CT examinations, the patient may undergo arteriography plus embolization or surgery to control the hemorrhage.

The CT image should be carefully examined for subtle signs of pancreatic injury because these patients may need immediate surgery or close observation for signs of complication. Duodenal perforation produces subtle but typical findings on CT, such as extraluminal air or fluid in the retroperitoneum or periportal region. Identifying these findings generally mandates surgical intervention. Duodenal hematoma may not require surgery but does mandate close observation. Other gut injury or perforation produces direct or indirect findings on CT in 50% to 94% of cases. However, if the CT is negative for gut injury in the face of a high clinical suspicion, laparoscopy, surgical exploration, or a period of observation plus repeat CT may be used to further evaluate the patient.

It may also be reasonable to use CT, in conjunction with the clinical information, to decide whether to observe patients in the hospital for a day or send them home promptly after evaluation in the emergency department. The high sensitivity of CT in detecting injuries that require observation in the hospital means that a negative CT may be adequate to release the patient to home in selected cases. US, however, has a substantially lower sensitivity to the kind of injuries that must be observed in the hospital. For this reason, a negative US is not adequate to safely release the patient to home. This weakness of US is reflected in the design of many outcomes-based investigations on the use of US in trauma: all keep patients with a negative US in the hospital for a period of observation of 12 to 48 hours before release.

There may be a rationale for creating a subcategory of stable patients with trivial trauma, a low clinical index of suspicion, and no signs or symptoms of intra-abdominal injury. In such patients, a negative US alone may be adequate to release them from observation at a lower cost than if CT had been used. CT is necessary, however, if there are any positive findings on US.

Category C

Patients with hematuria after blunt abdominal trauma require some modification to the imaging workup. All patients with gross hematuria and pelvic fracture require additional imaging of the bladder to exclude bladder rupture (absolute indication). A hemodynamically stable patient being evaluated with MDCT can easily undergo CT cystography using gravity drip infusion of dilute 2% contrast (300 to 500 cc) via an indwelling Foley catheter. Patients with microscopic or gross hematuria without evidence of pelvic fracture or suspected pelvic injury should be considered as a relative, not absolute, indication for additional CT cystography.

Identification of clinical indicators of bladder rupture is important when determining if additional bladder imaging is needed in trauma patients with gross hematuria without pelvic fracture or major pelvic injury. Clinical indicators of bladder rupture that may indicate the need for additional bladder imaging with CT or fluoroscopic cystography include suprapubic pain and tenderness, inability to void, low urine output or clots in urine, signs of major perineal trauma such as perineal swelling, hematoma, or blood per meatus. Patients with concomitant head injury, intoxication, altered sensorium, or previous history of bladder outlet obstruction or bladder surgery should be viewed with increased suspicion for bladder injury. If gross blood is identified from the urethral meatus or the prostate is mobile on digital examination (floating), a retrograde urethrogram should be performed first to rule out urethral injury.

CT images should be examined carefully for evidence of renal perfusion, hemorrhage, or extravasation of contrast or urine from the kidney or bladder. All but the worst renal injuries (renal pedicle and pelvis) are generally treated with observation; intraperitoneal bladder rupture is treated with surgical repair. Extraperitoneal bladder rupture is managed with urethral and suprapubic catheter drainage.

US plays little if any role in the evaluation of genitourinary trauma. Several studies have documented the inability of US to detect injuries of the kidney or bladder in trauma patients.

Appendix

CT Technique

CT evaluation of the abdomen and pelvis for blunt trauma does not require the use of oral contrast. The use of intravenous contrast (approximately 150 cc at 2 to 4 cc per second with a 60-second scan delay) is essential to identify visceral, vascular, or bowel injury. Scanning includes the lower lung fields through the floor of the pelvis, including the inferior aspect of the ischia, with image reconstruction at 2.5 to 3.0 mm image thickness. Delayed imaging through the pelvis (5 minutes) is generally performed if the patient is stable to allow better visualizing of the bladder.

For a CT cystogram, a Foley catheter is placed into the urinary bladder and 500 cc of dilute contrast is instilled into the bladder via the catheter, using the gravity drip technique, after completion of the abdomen and pelvic CT examination. Imaging of the pelvis commences once the rate of bladder contrast has decreased significantly or stopped. At the conclusion of the CT cystogram, the bladder should be drained through the Foley.

Abbreviations

• CT, computed tomography
• Med, medium
• Min, minimal
• NS, not specified
• US, ultrasound

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

Selection of appropriate radiologic imaging procedures for evaluation of adults with blunt abdominal trauma

Relative Radiation Level (RRL)

Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, an RRL indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Additional information regarding radiation dose assessment for imaging examinations can be found in the American College of Radiology (ACR) Appropriateness Criteria® Radiation Dose Assessment Introduction document (see the "Availability of Companion Documents" field).

The American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists, and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those exams generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U.S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panels on Vascular Imaging and Gastrointestinal Imaging

Panel Members: Gary S. Sudakoff, MD (Principal Author); E. Kent Yucel, MD (Chair, Expert Panel on Vascular Imaging); Max Paul Rosen, MD, MPH (Chair, Expert Panel on Gastrointestinal Imaging); Isaac R. Francis, MD (Chair, Expert Panel on Urologic Imaging); Richard A. Baum, MD; W. Dennis Foley, MD; Spencer B. Gay, MD; Frederick L. Greene, MD; M. Ashraf Mansour, MD; Frank J. Rybicki, MD, PhD

Not stated

Note: This guideline has been updated. The National Guideline Clearinghouse (NGC) is working to update this summary.

Electronic copies of the updated guideline: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.

None available

This summary was completed by ECRI on March 19, 2001. The information was verified by the guideline developer on March 29, 2001. This NGC summary was updated by ECRI on January 4, 2006. The updated information was verified by the guideline developer on January 19, 2006. This summary was updated by ECRI Institute on June 2, 2010.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .