K. Shanmuganathan

Abdominal injuries without hemoperitoneum: a potential limitation of focused abdominal sonography for trauma (FAST)

BACKGROUND Focused abdominal sonography for trauma (FAST) relies on hemoperitoneum to identify patients with injury. Blunt trauma victims (BTVs) with abdominal injury, but without hemoperitoneum, on admission are at risk for missed injury. METHODS Clinical, radiologic, and FAST data were collected prospectively on BTVs over a 12-month period. All patients with FAST-negative for hemoperitoneum were further analyzed. Examination findings and associated injuries were evaluated for association with abdominal lesions. RESULTS Of 772 BTVs undergoing FAST, 52 (7%) had abdominal injury. Fifteen of 52 (29%) had no hemoperitoneum by admission computed tomographic scan, and all had FAST interpreted as negative. Four patients with splenic injury underwent laparotomy. Six other patients with splenic injury and five patients with hepatic injury were managed nonoperatively. Clinical risk factors significantly associated with abdominal injury in BTVs without hemoperitoneum include: abrasion, contusion, pain, or tenderness in the lower chest or upper abdomen; pulmonary contusion; lower rib fractures; hemo- or pneumothorax; hematuria; pelvic fracture; and thoracolumbar spine fracture. CONCLUSIONS Up to 29% of abdominal injuries may be missed if BTVs are evaluated with admission FAST as the sole diagnostic tool. Consideration of examination findings and associated injuries should reduce the risk of missed abdominal injury in BTVs with negative FAST results.

Use of spiral computed tomography for the assessment of blunt trauma patients with potential aortic injury.

PURPOSE The purpose of this study was to prospectively examine the accuracy of contrast-enhanced spiral thoracic computed tomography (CEST-CT) for direct detection of traumatic aortic injury resulting from blunt thoracic trauma. METHODS During a 25-month period, all blunt trauma patients who had abnormal mediastinal contours on admission chest radiographs underwent CEST-CT. The presence and location of mediastinal blood and any direct signs of aortic injury, such as pseudoaneurysm, were recorded. Computed tomographic results were compared with results of aortography, when performed, surgery, or clinical status at discharge. RESULTS There were 7,826 patients classified as having blunt trauma admitted during the study. Of these, 1,104 (14.3%) had CEST-CT performed. Mediastinal hemorrhage was detected on 118 (10.7%) of all thoracic computed tomographic scans. Direct evidence of aortic injury was detected in 24 patients (20.3%) with mediastinal hemorrhage and 2.2% of all patients undergoing CEST-CT. In this prospective series, CEST-CT was 100% sensitive based on clinical follow-up; it was 99.7% specific, with 89% positive and 100% negative predictive values and an overall diagnostic accuracy of 99.7%. CONCLUSION CEST-CT is a valuable ancillary study for the detection of traumatic aortic injury. Spiral computed tomography is accurate for the detection and localization of both hemomediastinum and direct signs of aortic injury.

Imaging of Diaphragmatic Injuries

Multiple imaging modalities are available for the preoperative diagnosis of diaphragmatic injury. Chest radiographs are the initial and most commonly performed imaging study to evaluate the diaphragm after trauma. When chest radiography is indeterminate, spiral computed tomography (CT) with thin sections and reformatted images is the next study of choice, particularly because most hemodynamically stable patients with blunt diaphragm injury will require an admission CT examination to evaluate the extent and anatomical sites of coexisting thoracoabdominal injuries. Magnetic resonance imaging is used to evaluate the diaphragm for patients with clinical suspicion but an indeterminate diagnosis after chest radiography and spiral CT.

Determining the need for laparotomy in penetrating torso trauma: a prospective study using triple-contrast enhanced abdominopelvic computed tomography.

BACKGROUND The nontherapeutic laparotomy rate in penetrating abdominal trauma remains high and the morbidity rate in these cases is approximately 40%. Selective management, rather than mandatory laparotomy, has become a popular approach in both stab wounds and gunshot wounds. The advent of spiral technology has stimulated a reassessment of the role of computed tomography (CT) in many aspects of trauma care. We prospectively investigated the current utility of triple-contrast CT as a diagnostic tool to facilitate initial therapeutic management decisions in penetrating torso trauma. METHODS We studied hemodynamically stable patients with penetrating injury to the torso (abdomen, pelvis, flank, back, or lower chest) without definite indication for laparotomy, admitted to our trauma center during the 1-year period from 7/99 through 6/00. Patients underwent triple-contrast enhanced spiral CT as the initial study. A positive CT scan was defined as any evidence of peritoneal violation (free air or fluid, contrast leak, or visceral injury). Patients with positive CT, except those with isolated solid viscus injury, underwent laparotomy. Patients with negative CT were observed. RESULTS There were 75 consecutive patients studied: mean age 30 years (range 15-85 years); 67 (89%) male; 41 (55%) gunshot wound, 32 (43%) stab wound, 2 (3%) shotgun wound; mean admission systolic blood pressure 141 mm Hg (range 95-194 mm Hg); 26 (35%) had positive CT and 49 (65%) had negative CT. In patients with positive CT, 18 (69%) had laparotomy: 15 therapeutic, 2 nontherapeutic, and 1 negative. Five patients had isolated hepatic injury and 2 had hepatic and diaphragm injury on CT and all were successfully managed without laparotomy. Of these seven patients, three had angioembolization and two had thoracoscopic diaphragm repair. In patients with negative CT, 47/49 (96%) had successful nonoperative management and 1 had negative laparotomy. The single CT-missed peritoneal violation had a left diaphragm injury at laparotomy. CT accurately predicted whether laparotomy was needed in 71/75 (95%) patients. CONCLUSION In penetrating torso trauma, triple-contrast abdominopelvic CT can accurately predict need for laparotomy, exclude peritoneal violation, and facilitate nonoperative management of hepatic injury. Adjunctive angiography and investigation for diaphragm injury may be prudent.

Gallbladder Injury Secondary to Blunt Trauma: CT Findings

Objective Our objective was to determine CT findings of gallbladder injury secondary to blunt trauma. Materials and Methods Computed tomography scans and medical records of seven patients diagnosed with gallbladder injury secondary to blunt trauma, including six surgically confirmed cases and one presumptive diagnosis based on CT findings, were reviewed retrospectively to delineate CT findings associated with gallbladder injury. Evaluation of CT scans included assessment of gallbladder distention, wall thickness and contour, intraluminal contents, presence of pericholecystic fluid, and associated injuries. Data obtained included age, gender, mechanism of injury, surgical and pathologic findings when available, treatment, morbidity, and mortality. Results Four patients had gallbladder contusions and three had either gallbladder laceration, partial avulsion, or intraluminal hemorrhage. The spectrum of CT findings included pericholecystic fluid (seven), ill defined contour of the gallbladder wall (four), high density intraluminal hemorrhage (four), mass effect on the duodenum (three), and gallbladder collapse (one). No combination of findings was specific for the type of injury. The most common associated injuries were pericholecystic liver lacerations and duodenal hematoma or perforation. Conclusion The CT finding of an ill defined contour of the gallbladder wall, a collapsed lumen, or high density intraluminal hemorrhage, especially in the presence of pericholecystic fluid, strongly suggests primary gallbladder injury.

Magnetic resonance imaging of ligamentous injury of the cervical spine

This study is a retrospective review of 43 patients with acute cervical spine trauma, including 97 ligamentous injuries of various types diagnosed by magnetic resonance imaging (MRI). Three general patterns of ligamentous injury were observed, including: complete rupture; partial avulsion or attenuation of the ligament, without frank rupture; and combined osseous and ligamentous fragment. Overall, proton density and T2*-weighted gradient-echo or T2-weighted spinecho images in the sagittal plane provided the best evaluation of the spinal ligaments. Axial proton density and T2*-weighted gradient images were useful only in assessment of the trasverse portion of the cruciate ligament. By providing direct visualization of the spinal ligaments, MRI demonstrated multiple case of ligamentous injury that were greater than expected or unexpected from plain radiographic and computed tomographic findings. Surgical proof was obtained for 11 patients with 14 ligamentous injuries that were diagnosed by MRI independently. There were two false-positive MRI diagnoses for posterior longitudinal ligament rupture, but no false-negatives among these 11 patients. This study indicates that MRI allows accurate diagnosis of cervical spine ligamentous injuries that are otherwise only inferred by the mechanism of injury and resulting spinal alignment.

Imaging of traumatic diaphragmatic injuries

Traumatic diaphragmatic injury (TDI) occurs in approximately 6% of patients after major blunt trauma to the abdomen. Detection of such injuries is often problematic because of nonspecific clinical signs and the presence of additional intra-abdominal injuries. As the use of nonsurgical management to treat solid organ injuries increases, helical computed tomography (CT) must play a much greater role in the detection of intra-abdominal injuries. Therefore, it is crucial that diaphragmatic injuries are not overlooked, as fewer will be diagnosed at exploratory laparotomy. This article reviews the recent advances in helical CT that are helpful in diagnosing TDI and addresses the selected application of magnetic resonance imaging.

Tension Pneumocephalus and Tension Orbital Emphysema Following Blunt Trauma

We present the first reported case of vision loss due to tension orbital emphysema associated with tension pneumocephalus resulting from blunt trauma. In the setting of trauma, intraorbital air indicates paranasal sinus-orbital communication. Tension orbital emphysema may cause vision loss through optic nerve compression, ischemia, or contusion; or central retinal artery occlusion. Vision impairment after craniofacial injury should prompt urgent computed tomography. Tension orbital emphysema with associated vision impairment requires treatment including direct decompression and, in some cases, high-dose steroids to preserve vision. Increases in sinus pressure from coughing, nose-blowing, or vomiting should be avoided until definitive treatment can be instituted.

Trauma radiology: Part V. Imaging of acute cervical spine trauma.

Cervical spine injury constitutes a major cause of morbidity resulting from trauma. The consequences of a missed “significant” injury can be devastating for the patient and can create potential medical legal consequences for involved physicians. Multiple imaging modalities can be applied to imaging of the cervical spine after trauma, including radiography, computed tomography (CT), myelography, CT myelography and magnetic resonance imaging (MRI). Controversy exists concerning the appropriate number of radiographic views required for the screening assessment of cervical spine injuries. CT clarifies uncertain radiological findings, identifies subtle fractures in patients with neck pain or with neurological deficits but with normal radiographs, determines details of injury, and assists in operative planning. MRI has virtually replaced myelography and CT myelography in evaluating the traumatized cervical spine. MRI is more accurate than CT with intrathecal contrast in delineating epidural pathology, ligament injury, soft-tissue edema, and cord parenchymal injury. Information derived from MRI guides appropriate management and has value in predicting injury outcome. We consider indications for and relative merits of these various diagnostic modalities, and we describe imaging features of major patterns of cervical spine injury.

Trauma Radiology: Part I. Computerized Tomographic Imaging of Abdominal Trauma

The value of computerized tomography (CT) scanning for identification of injuries sustained primarily from blunt trauma to the abdomen and pelvis is well established. During the 1980s, numerous articles appeared comparing the value of CT versus diagnostic peritoneal lavage (DPL) as a screening test for intraperitoneal injury. A consensus emerged recognizing the complimentary and different kinds of information provided by each study. CT is indicated in hemodynamically stable patients; to assess the retroperitoneum; after indeterminant DPL results; potentially in patients with positive DPL results by cell count; whenever PDL is contraindicated; in patients with persistent abdominal pain despite a negative DPL; for penetrating flank trauma; for mild abdominal tenderness in alert patients; and arguably for patients with unreliable physical examination. The accuracy of CT is dependent on speed and quality of the scanner, attention to technique to provide optimal oral and intravenous contrast enhancement, and experience of the image interpreter. In general, the accuracy of CT for detection of solid visceral injuries (including in the liver, the spleen, and the kidneys) and for evaluation of the retroperitoneum is well established. Recent studies indicate that CT also offers important information regarding pancreatic and hollow viscous injuries. Fast scanning with a power-injected intravenous contrast bolus can provide localization of active bleeding sites, with important implications for management by surgery or interventional angiography. We review the CT imaging findings typically observed with a variety of abdominal/pelvic injuries.