Visceral injury without hemoperitoneum: A limitation of screening abdominal sonography for trauma

Abdominal sonography for the detection of hemoperitoneum has become increasingly popular as a screening test for visceral injury after blunt trauma. The purpose of this study was to determine the frequency, severity, and clinical significance (outcome) of abdominal organ injuries that occur without hemoperitoneum on the initial evaluation of blunt abdominal trauma patients.During a 12-month period, 3392 blunt trauma patients were admitted to our center. Sonographic studies were performed as an initial screening evaluation to determine the presence of hemoperitoneum in 772 (22.7%) of these patients. Abdominal visceral injuries were verified by computed tomography (CT) or surgery in 196 (5.8%) of all blunt trauma admissions. Sonography, CT, and operative findings were reviewed to determine the presence or absence of hemoperitoneum in patients with abdominal injury. Patients with abdominal visceral injury without hemoperitoneum were further analyzed to identify the type of injury and the management required.A total of 246 abdominal injuries were identified in 196 patients. Fifty (26%) patients with abdominal visceral injuries diagnosed by admission CT scan had no evidence of hemoperitoneum. Admission sonography performed in 15 (30%) of these 50 patients also showed no evidence of hemoperitoneum. Visceral injuries detected by CT in the patients without hemoperitoneum included 22 of 100 splenic injuries (22%), 18 of 91 hepatic injuries (20%), 12 of 26 renal injuries (46%), and 1 of 9 mesenteric injuries (11%). Surgery was required to manage injuries in 10 of these patients.Up to 26% of blunt trauma patients with abdominal visceral injuries do not have associated hemoperitoneum identified on admission abdominal CT or sonography. Dependence on hemoperitoneum as the sole criterion of abdominal visceral injury after blunt trauma will result in falsely negative examinations and will miss potentially significant injuries.     

Blunt abdominal trauma: screening us in 2,693 patients

PURPOSE: To evaluate the accuracy of screening abdominal ultrasonography (US) in patients with blunt abdominal trauma. MATERIALS AND METHODS: Patients with blunt abdominal trauma underwent US. The abdomen and pelvis were scanned for free fluid, the visceral organs were assessed for heterogeneity, and duplex US was performed if necessary. Empty bladders were filled with 200-300 mL of sterile saline through a Foley catheter. US findings were considered positive if free fluid was present or if parenchymal abnormalities that could be consistent with trauma were detected. Screening US results were compared with findings of diagnostic peritoneal lavage, repeat US, computed tomography (CT), cystography, surgery, and/or autopsy and/or the clinical course. RESULTS: Findings from 2,693 US examinations were evaluated and were positive in 145 of 172 patients with injuries (sensitivity, 84%) and 64 (89%) of 72 patients who ultimately underwent laparotomy with surgical repair of injuries. False-negative findings were retroperitoneal injury, bowel injury, and intraperitoneal solid organ injury without hemoperitoneum. No patient with false-negative findings died. Specificity of US was 96% (2,429 of 2,521 patients), and overall accuracy was 96% (2,574 of 2,693 patients). Positive predictive value was 61% (145 of 237 patients), and negative predictive value was 99% (2,429 of 2,456 patients). CONCLUSION: Abdominal US is useful in screening for injury in patients with blunt abdominal trauma, and its use represents a notable change in institutional practice. Diagnostic peritoneal lavage is rarely performed, and CT is used when screening US findings are positive, when injury is clinically suspected despite negative US findings, or when US is not available.     

CT features of blunt abdominal aortic injury

Abdominal aortic injuries are uncommon following blunt trauma, with relatively few reported series in the radiology literature. This study was conducted to identify common locations and imaging features of blunt traumatic abdominal aortic injury, the presence of associated visceral and osseous injuries, and the mechanisms of trauma. A retrospective review of 9,213 trauma registry entries over a 7-year period yielded 103 patients with aortic injuries, 12 of which had direct signs of abdominal segment involvement (dissection flap, focal intimal injury, intramural hematoma, active extravasation of contrast, or pseudoaneurysm formation). The majority (75 %) was isolated to the abdomen-67 % of which was infrarenal, 33 % suprarenal-while the other 25 % was a contiguous extension from a thoracic injury. Abdominal aortic injuries were uncommonly seen in isolation: all but one patient (92 %) demonstrated either retroperitoneal blood or stranding, hemoperitoneum, and/or CT signs of hypoperfusion complex, and only one patient (8 %) had no associated solid organ or skeletal injuries. All patients had a mechanism of injury which involved direct trauma to the abdomen, most commonly a motor vehicle collision. Similar to other recent series, there was an increased rate of abdominal segment injury (11.7 % of all aortic injuries) in this series compared to more remote autopsy series. This difference is likely due to detection of injuries which went undiagnosed before the widespread use of multidetector CT, which has become the standard of care for both acute evaluation following blunt trauma and for follow-up.     

Gallbladder blunt trauma: comparison between radiologic and anatomo-surgical findings

PURPOSE: To assess the diagnostic accuracy and the possible role of ultrasonography (US) and Computed Tomography (CT) in a small group of patients who had a blunt abdominal trauma involving the gallbladder. MATERIAL AND METHODS: We retrospectively reviewed the US and CT findings of five patients with surgically confirmed post-traumatic gallbladder injury. The whole series consisted of 196 consecutive patients submitted to laparotomy for blunt abdominal trauma in the past 7 years. The following US and CT findings were considered at least suggestive of a possible post-traumatic gallbladder injury: pericholecystic fluid collection, ill-defined wall margin, collapsed lumen, high intraluminal density. RESULTS: At surgery, the following findings were observed: gallbladder hematoma (1 case), acute colecystitis (1 cases), gallbladder tear (3 cases), gallbladder tear associated with post-traumatic hepatic injuries (2 cases), duodenal tear (2 cases), hemoperitoneum alone (2 cases), hemoperitoneum associated with choleperitoneum (1 case), choleperitoneum alone (1 case). The US and CT findings were pericholecystic fluid collections (4 cases), ill-defined gallbladder wall margins (3 cases), collapsed lumen with intraluminal high density (1 case) and free intraperitoneal fluid collections (4 cases). They were suggestive of a possible post-traumatic gallbladder injury in all the five patients. CONCLUSIONS: The radiologic findings of our five patients were suggestive of a gallbladder damage but did not permit to distinguish minor from major injuries, the latter requiring surgical treatment. US proves to be a useful screening tool which can also help timing surgery in these patients. CT confirmed the US suspicions and also permitted accurate assessment of associated post-traumatic injuries to the liver and duodenum. Nevertheless, the clinical presentation was the most important factor as to the therapeutic management of these blunt abdominal trauma patients.     

Evaluation of non-contrast-enhanced CT in blunt abdominal trauma]

We compared the findings of noncontrast-enhanced CT with those of contrast-enhanced CT in 126 patients with blunt abdominal trauma to evaluate the usefulness of noncontrast-enhanced CT. In 112 of the patients, visceral injuries were confirmed by surgery or clinical follow-up including CT. Although noncontrast-enhanced CT diagnosed all patients with 12 intestinal injuries requiring immediate surgery, contrast-enhanced CT missed two of these patients because high density hematomas on noncontrast-enhanced CT became isodense after IV administration of contrast material. However, contrast-enhanced CT was superior to noncontrast-enhanced CT in the diagnosis of hepatic and renal injuries. A case of renal artery occlusion was only visualized on contrast-enhanced CT. We conclude that both noncontrast- and contrast-enhanced CT should be performed for the CT evaluation of blunt abdominal trauma.     

Prospective evaluation of handheld ultrasound in the diagnosis of blunt abdominal trauma

OBJECTIVES: To evaluate the Sonosite 180 handheld ultrasound in the diagnosis of haemoperitoneum in blunt abdominal trauma. METHODS: Trauma ultrasound using the Focused Assessment with Sonar for Trauma (FAST) technique was performed using the Sonosite 180 handheld ultrasound during the primary survey of adult patients triaged to the resuscitation room with multiple trauma or suspected abdominal injury. The ultrasound findings were compared against the investigation of choice of the attending surgeon/accident & emergency physician--CT, DPL, laparotomy or clinical observation. RESULTS: 50 patients who had sustained blunt abdominal trauma were evaluated using FAST. Satisfactory images were obtained in 96%. There were 5 true positive scans confirmed by CT, DPL or laparotomy. There were no false negative or false investigations. The sensitivity and specificity of handheld FAST was 100%. CONCLUSIONS: Handheld ultrasound using the Sonosite 180 system can be successfully used by appropriately trained doctors as the primary investigation in the acute evaluation of blunt abdominal trauma.     

Blunt abdominal trauma in children: evaluation with emergency US

PURPOSE: To assess the accuracy of emergency abdominal ultrasonography (US) in the detection of both hemoperitoneum and parenchymal organ injury in children. MATERIALS AND METHODS: Imaging findings were recorded prospectively in 744 consecutive children who underwent emergency US from January 1995 to October 1998; free fluid and parenchymal abnormalities of specific organs were also noted. Patients with intraabdominal injuries were identified retrospectively. Computed tomographic (CT) findings, intraoperative findings, and clinical outcome were compared with the initial US findings. Sensitivity, specificity, and positive and negative predictive values were calculated for patients who underwent CT, laparotomy, or both after US. RESULTS: Seventy-five (10%) of 744 patients had intraabdominal injuries, and US depicted free fluid in 42 of them. US had 56% sensitivity, 97% specificity, 82% positive predictive value, and 91% negative predictive value for detection of hemoperitoneum alone. US helped identify parenchymal abnormalities that corresponded to actual organ injury without accompanying free fluid in nine patients (12%). Inclusion of identification of parenchymal organ injury at US increased the sensitivity of US to 68%, with an accuracy of 92%. CONCLUSION: US for blunt abdominal trauma in children is highly accurate and specific, but moderately sensitive, for detection of intraabdominal injury.     

Sonography in a clinical algorithm for early evaluation of 1671 patients with blunt abdominal trauma

OBJECTIVE: The purpose of this study was to evaluate the efficacy of sonography in our algorithm when differentiating patients with blunt abdominal trauma who need immediate surgery from patients who would benefit from further diagnostic workup or who need no treatment. SUBJECTS AND METHODS: We performed abdominal sonography as the primary screening tool in 1671 consecutive patients in our prospective study. Radiologists performed sonography in the trauma room within minutes of the arrival of each patient. Hemodynamic instability in conjunction with positive sonographic findings led to emergency laparotomy. Otherwise, positive sonographic findings warranted additional diagnostic tests. Observing free fluid or organ injury caused us to categorize sonographic findings as positive. RESULTS: Sonography correctly identified all patients requiring emergency laparotomy. No inconclusive laparotomies were performed in this group. The sensitivity of sonography for revealing intraabdominal injury was 88%, the specificity was 100%, and the accuracy was 99%. In 132 patients (8%), abdominal CT was performed. CT revealed relevant posttraumatic abnormalities in 61% of all patients. Four hundred seventy patients with negative sonographic findings were discharged approximately 12 hr after admission; two of these patients (0.4%) were mistakenly discharged. Trauma scores did not influence the efficacy of sonography. CONCLUSION: Our algorithm that uses sonography as the primary diagnostic tool provides accurate, fast, cost-effective, and noninvasive initial management of patients with blunt abdominal trauma. Our test characteristics were excellent indicators of the need for emergency laparotomy. Sonography also achieves high values in revealing relevant injury. Our algorithm produced medically satisfactory and economically prudent management of patients with blunt abdominal trauma.     

Using contrast-enhanced helical CT to visualize arterial extravasation after blunt abdominal trauma: incidence and organ distribution.

OBJECTIVE: We evaluated the incidence and organ distribution of arterial extravasation identified using contrast-enhanced helical CT in patients who had sustained abdominal visceral injuries and pelvic fractures after blunt trauma. SUBJECTS AND METHODS: Five hundred sixty-five consecutive patients from four level I trauma centers who had CT scans showing abdominal visceral injuries or pelvic fractures were included in this series. The presence or absence of arterial extravasation, as well as the anatomic sites of arterial extravasation, was noted. We obtained clinical follow-up data, including surgical or angiographic findings. RESULTS: In our series, 104 (18.4%) of 565 patients had arterial extravasation. Of the 104 patients, 81 (77.9%) underwent surgery, embolization, or both. The combined rate of surgery or embolization in patients with arterial extravasation was statistically higher than expected at all four institutions (p <0.001). The spleen was the most common organ injured, occurring in 277 (49.0%) of 565 patients, and arterial extravasation occurred in 49 (17.7%) of 277 patients with splenic injury. Several other visceral injuries were associated with arterial extravasation, including hepatic, renal, adrenal, and mesenteric injuries. CONCLUSION: Based on the limited reports of arterial extravasation in the nonhelical CT literature, the percentage (18%) of clinically stable patients in our study with CT scans showing arterial extravasation was higher than anticipated. This finding likely reflects the improved diagnostic capability of helical CT. Although the spleen and liver were the organs most commonly associated with arterial extravasation, radiologists should be aware that arterial extravasation may be associated with several other visceral injuries.     

Penetrating stab wounds to the abdomen: use of serial US and contrast-enhanced CT in stable patients

PURPOSE: To evaluate the usefulness of computed tomography (CT) and ultrasonography (US) for the initial assessment of penetrating abdominal stab wounds in patients who presented to the emergency department without indication for immediate laparotomy. MATERIALS AND METHODS: During 36 months, 32 patients with a penetrating stab wound to the abdomen were examined with serial US (at admission and 12 hours later) and helical CT, with contrast material administered orally, intravenously, and rectally. Presence of hemoperitoneum and integrity of solid and hollow viscera were evaluated with both methods. Sonograms were interpreted by the radiologist who performed the examination, and CT images were independently evaluated by two radiologists. Findings of both techniques were compared with clinical outcome and/or surgical findings. RESULTS: One (3.1%) of 32 patients required surgery: Surgical findings were massive hemoperitoneum and an extensive hepatic laceration. Both US and CT depicted these abnormalities. Thirty-one (96.9%) patients were treated conservatively, without surgery, and remained asymptomatic during 28 days of clinical follow-up after discharge from the hospital. US and/or CT showed intraperitoneal abnormalities in 21 of these patients. In 11 patients, both methods showed no evidence of visceral injury or hemoperitoneum, and none of these patients required surgery. CONCLUSION: Serial US and CT help guide treatment for stable patients with penetrating stab injuries to the abdomen.     

Treatment of blunt hepatic injuries: role of CT

Serial dynamic upper abdominal computed tomography (CT) studies were performed on 20 patients as part of the conservative treatment of blunt hepatic injuries (hematoma, laceration, or fracture). Fourteen of these patients had either major or minor associated hemoperitoneum. In 13 patients, hemoperitoneum was either significantly reduced or absent by 1 week. A severe delayed hemorrhage occurred in one patient 7 1/2 days after admission; a large and unchanged volume of intraperitoneal fluid had been seen on a preceding abdominal CT scan. One other patient who had a satisfactory response underwent surgery for a pancreatic laceration. Serial abdominal CT studies are an integral part of the conservative treatment of blunt hepatic injuries and seem to be useful in monitoring resorption of hemoperitoneum and the pattern of healing of intrahepatic hematomas, lacerations, and fractures.     

Blunt abdominal trauma: should US be used to detect both free fluid and organ injuries?

PURPOSE: To evaluate abdominal ultrasonography (US) for indirect (with free fluid analysis only) and direct (with free fluid and parenchymal analysis) detection of organ injury in patients with blunt abdominal trauma, with findings at computed tomography (CT) and/or surgery as the standard of diagnosis. MATERIALS AND METHODS: Abdominal US was performed at hospital admission in consecutive patients with blunt abdominal trauma. The presence of free peritoneal fluid and organ injury were recorded and compared with results of abdominal CT in all hemodynamically stable patients. When US results were considered false-negative for free fluid or organ injury compared with CT results, repeat US was performed within 6 hours. Admission and second US results were compared with CT and/or surgical results to determine sensitivity, specificity, negative predictive value, and positive predictive value of US with regard to the presence of free intraperitoneal fluid and/or organ injury. RESULTS: Two hundred five hemodynamically stable patients underwent abdominal US and CT. CT revealed free fluid in 83 patients and organ injury in 99. Thirty-one (31%) of 99 patients with organ injury did not have free fluid at CT. Three (10%) of the 31 patients required surgery or angiographic embolization. The sensitivity of admission US was 93% (77 of 83 cases) for the diagnosis of free fluid, 41% (39 of 99) for directly demonstrating organ injury, and 72% (71 of 99) for suggesting organ injury by means of both free fluid and organ analysis. At second US, these sensitivities were 96% (80 of 83 cases), 55% (54 of 99) and 84% (83 of 99), respectively. CONCLUSION: US is highly sensitive for the detection of free intraperitoneal fluid but not sensitive for the identification of organ injuries. In hemodynamically stable patients, the value of US is mainly limited by the large percentage of organ injuries that are not associated with free fluid.     

Blunt abdominal trauma: clinical value of negative screening US scans

PURPOSE: To assess clinical and surgical outcomes in patients with blunt abdominal trauma and negative screening ultrasonographic (US) scans. MATERIALS AND METHODS: From a database of 4,000 patients who underwent screening US for suspected blunt abdominal trauma at a level 1 trauma center, the authors retrospectively identified 3,679 patients with negative US findings. In these patients, outcome was determined by means of retrospective review of the trauma registry and all radiologic, surgical, and autopsy reports. In patients with false-negative findings at screening US, all imaging studies and medical charts were also reviewed. Proportions were statistically compared by means of the Pearson chi(2) and Fisher exact tests. Monte Carlo estimation was applied when expected frequencies were low. RESULTS: Among the 3,679 patients with negative findings at screening US, 99.9% (n = 3,641) had no injuries (true-negative findings). Differences in true-negative rates as a function of year (P >.5) or time of day (P >.3) were not significant. Among the 3,641 patients with true-negative findings, 93.6% (n = 3,407) required no additional tests and 6.4% (n = 234) underwent computed tomography or other tests. The percentage of patients who underwent additional tests was significantly higher in the 1st year of the study (19.2%) than in subsequent years (all comparisons, P <.001). Thirty-eight patients had false-negative US findings for abdominal injury. The injuries that were missed in 24 patients were nonsurgical (those that were treated successfully without intervention or were considered minor at autopsy) and those in 14 patients were surgical (required surgical intervention). Cumulatively, 65 injuries were missed. The six most common injuries included retroperitoneal hematoma (n = 13) and injuries in the spleen (n = 10), liver (n = 9), kidney (n = 8), adrenal gland (n = 8), and small bowel (n = 7). Twenty-five of the 38 patients had no or trace hemoperitoneum. Mean diagnostic delay until recognition of missed injury was 16.8 hours +/- 4.3 (standard error of the mean). The missed injury was identified within 12 hours in 19 of the 38 patients and within 24 hours in 34. CONCLUSION: The combination of negative US findings and negative clinical observation virtually excludes abdominal injury in patients who are admitted and observed for at least 12-24 hours.     

Hypotensive patients with blunt abdominal trauma: performance of screening US

PURPOSE: To determine retrospectively the accuracy of screening ultrasonography (US) in patients with hypotension (systolic blood pressure or =2) (consensus by three readers) and were assigned to a low- or high-risk group according to the presence of hematuria and/or axial fracture on radiographs. Screening US results were compared with findings with the best available reference standard (computed tomography [CT]), repeat US, other diagnostic test, laparotomy, autopsy, clinical course). Data were compared by using chi(2) or Fisher exact test, depending on expected frequencies, with Bonferroni correction for multiple comparisons. Continuous variables were compared by using unpaired Student t test or Mann-Whitney U test, depending on data distribution. RESULTS: The study included 77 male and 51 female patients (mean age, 42 years). Sensitivity was 85% (44 of 52) for detection of any injuries, 97% (30 of 31) for surgical injuries (ie, injuries requiring surgery), and 100% (10 of 10) for fatal injuries. Specificity was 96% (73 of 76), 82% (80 of 97), and 69% (81 of 118), and accuracy was 91% (117 of 128), 86% (110 of 128), and 71% (91 of 128), for respective injury categories. One nonfatal surgical injury was missed in a high-risk patient. For each injury category, frequency of injury in patients with a fluid score of 2 or more was nine times that in patients with a score of 0 (P < .001 for all comparisons). Frequency of false-negative US findings in high-risk patients was eight times that in low-risk patients (P < .01). CONCLUSION: In patients who are hypotensive after blunt abdominal trauma and not hemodynamically stable enough to undergo diagnostic CT, negative US findings virtually exclude surgical injury, while positive US findings indicate surgical injury in 64% of cases.     

Changes in splenic size after abdominal trauma

After blunt abdominal trauma, the spleen often increases in volume on serial computed tomographic (CT) scans. To determine the frequency and significance of such enlargement, the authors performed a retrospective analysis of 44 hemodynamically stable patients who had experienced recent blunt abdominal trauma. The severity of splenic, hepatic, or other visceral injuries seen on each CT scan was numerically scored, and the amount of intraperitoneal fluid was assessed. Twenty-five patients (57%) had over 10% enlargement (average enlargement, 56%) on follow-up scans. Increasing volume did not correlate with clinical deterioration or the need for splenectomy. It did correlate modestly with the amount of blood in the peritoneum on CT scans, the number of units of blood transfused, and two clinical indexes of systemic trauma. Therefore, an enlarging spleen is not a CT indicator of a deteriorating clinical condition. This phenomenon is most likely due to marked adrenergic stimulation after injury and changing fluid volumes.     

Bowel and mesenteric injury following blunt abdominal trauma: evaluation with CT

Computed tomography (CT) used in cases of blunt abdominal trauma has been found sensitive in detection of bowel and mesenteric injuries and discrimination of operable from nonoperable candidates. In 51 patients with suspected bowel or mesenteric injury following blunt abdominal trauma, CT correctly depicted bowel hematoma or mesenteric injury in 17 of 19 nonoperable patients (89%) and severe injuries in one patient who died preoperatively. In 26 of 28 patients who underwent therapeutic laparotomy (93%), initial CT enabled identification of surgically confirmed injuries. In two cases, initial scan misinterpretation delayed diagnosis of serious bowel injuries. The correct interpretation was rendered preoperatively and at blind retrospective review. CT findings that correlated with bowel or mesenteric injury requiring surgery were free peritoneal fluid (27 of 28, 96%), mesenteric infiltration (24 of 28, 86%), thick-walled bowel (17 of 28, 61%), associated abdominal injuries (12 of 28, 43%), and free air (nine of 28, 32%). In nonoperable cases, CT scans demonstrated bowel thickening (84%) but less frequently peritoneal fluid (21%), mesenteric infiltration (26%), or associated injuries (5%). In three of four patients who underwent nontherapeutic laparotomy, preoperative CT correctly imaged the limited abdominal injuries.     

Small bowel rupture after blunt trauma: Computed tomographic signs and their sensitivity

The purpose of this study is to describe the characteristic computed tomographic (CT) signs of small bowel perforation after blunt abdominal trauma and to evaluate their sensitivity. Nineteen preoperative CT scans were obtained from 16 patients with surgically proven small bowel rupture secondary to blunt abdominal trauma. Only the CT findings described in the original CT reports were used. Eleven of 19 CT scans (58 %) had findings that were unequivocal for bowel rupture (i.e., extraluminal air and/or extravasation of oral contrast medium). Seven CT scans (37 %) had findings that were suggestive of severe small bowel injury (i.e., focal small bowel wall thickening and/or free peritoneal fluid without other accompanying organ injuries). In all, 95 % of cases of small bowel rupture had either pathognomonic or suggestive CT findings. One CT scan did not demonstrate small bowel wall thickening, although a hemoperitoneum was present. CT is a sensitive method for suggesting severe small bowel injury and rupture secondary to blunt abdominal trauma.     

The value of non-contrast-enhanced CT in blunt abdominal trauma

The usefulness of non-contrast CT, limited to the upper abdomen, in conjunction with conventional IV contrast-enhanced scanning was studied prospectively in 190 patients who had sustained blunt abdominal trauma. In 78, visceral injuries were confirmed at surgery or at follow-up CT. Of the patients with injuries, 14 (18%) had hyperdense hematomas on the non-contrast studies that became isodense after IV administration of contrast material. These hematomas generally were small and posed an immediate threat to life in only one patient (0.5% of all subjects). In 13% of patients with injury (5% of the total), the additional information did influence treatment planning (surgery in two and intensive conservative treatment in eight). Compared with conventional contrast scanning, the combined non-contrast-contrast technique increased the scanning time only by about 5 1/2 min, but it improved the sensitivity and accuracy of CT in detecting visceral injuries from 74% and 84% to 92% and 91%, respectively (p less than or equal to .003 and p less than or equal to .04). Although contrast-enhanced scanning alone accurately depicts visceral injuries requiring surgical treatment, the incorporation of a non-contrast sequence can detect a subgroup of patients who require intensive conservative management with bed rest and close observation. This additional information can be obtained expeditiously, with minimal additional effort or intervention. The use of non-contrast scanning alone is not recommended.     

The clinical impact of CT for blunt abdominal trauma

The use of computed tomography (CT) has had a tremendous impact on the evaluation and management of blunt abdominal trauma. It is noninvasive, easy to perform, and has been shown to be highly sensitive (100%), specific (96.8%), and accurate (97.6%). The use of CT has helped decrease the total number of laparotomies performed for abdominal trauma at this institution (231 in 1975-1976, 74 in 1983) as well as the number of negative and nontherapeutic laparotomies. The use of other diagnostic tests such as radionuclide scans and angiography in blunt abdominal trauma has been virtually replaced by CT. Of the 41 peritoneal lavages performed in 1983, 39 were in patients who were in the operating room for treatment of other extraabdominal injuries (i.e., closed head injury, severe extremity trauma).     

Focused abdominal US in patients with trauma

PURPOSE: To evaluate the accuracy of focused abdominal ultrasonography (US) in detecting abdominal injuries that require in-hospital patient treatment in the setting of blunt abdominal trauma. MATERIALS AND METHODS: One thousand ninety patients with blunt abdominal trauma were assessed with focused abdominal US within 30 minutes of arrival at the hospital. Focused abdominal US results were positive if intra- or retroperitoneal fluid was detected. Patients with negative US results and no other major injuries were observed in the emergency department for 12 hours before discharge. Patients who deteriorated clinically after negative initial US underwent repeat US and/or emergency abdominopelvic computed tomography (CT). Patients with positive or indeterminate US results underwent emergency abdominopelvic CT. RESULTS: Nine hundred seventy-four (89%) patients had negative focused abdominal US results; eight of these underwent CT. Sixty-six (6%) had positive US results. Four (0.4%) had false-negative and 19 (1.7%) had false-positive US results. Twenty-seven (2.5%) had indeterminate US results; of these, five (18.5%) had positive CT results. One hundred twenty-four (11.4%) required emergency CT. After indeterminate cases were excluded, focused abdominal US had 94% sensitivity, 98% specificity, 78% positive predictive value, 100% negative predictive value, and 95% accuracy. CONCLUSION: Focused abdominal US has a high negative predictive value for major abdominal injury in patients with blunt abdominal trauma.