Diagnostic imaging strategies before and after transcatheter arterial embolization in patients with major abdominal and pelvic trauma

Abstract

Selected trauma patients with severe abdomino-pelvic injuries can be treated with transcatheter arterial embolization (TAE). The present investigation has studied the usefulness of diagnostic imaging in the forefield and aftermaths of embolization. Aims: To evaluate specific radiological signs on trauma admission imaging prior to TAE that may help the interventional radiologist (IR) to rapidly assess the injured pelvic arteries. To investigate the hemodynamic changes over time after TAE of the splenic artery with means of Doppler. To evaluate the diagnostic accuracy of contrast-enhanced ultrasound after TAE of the spleen for posttraumatic lesion characterization and detection. <br><br>

Patients and methods: In 95 patients with pelvic trauma and suspected pelvic artery injury, fracture size and location on pelvic X-ray (PXR) and arterial blush and hematoma on computed tomography (CT) were compared with findings of arterial injury on angiography. Fisher’s exact test was used for comparison of categorical data and receiver operating characteristic curve statistic was used for comparison of continuous data with the reference method angiography. Of 22 patients with TAE of the splenic artery, intraparenchymal Doppler was performed at three different time intervals in 17 patients. Velocity parameters were sampled from three different sites and parameters for systolic inflow and intraparenchymal resistance were calculated. Seventeen healthy volunteers were used as control group. All 22 patients were also examined with contrast-enhanced ultrasound (CEUS) for detection of different posttraumatic lesions and injury severity at early (one week after TAE) and late (2-4 months after TAE) - follow up. Contrast-enhanced CT was used as standard of reference. <br><br>

Results: The overall presence or absence of fracture on PXR and of hematomas on CT was moderately accurate for arterial injuries in the same segment. Including only fractures with major displacements and larger hematomas increased the specificity to a clinically acceptable level at the cost of reduced sensitivity. Presence of arterial blush on CT was highly specific for arterial injury. Normalization of the Doppler parameters indicated recovery of intrasplenic blood flow by formation of collaterals. CEUS was accurate for detection of significant posttraumatic lesions and grading of the injury severity.<br><br>

Conclusions: In the hemodynamic unstable patient with pelvic injury, PXR is a useful tool for rapid assessment and occlusion of the injured arteries. Contrast enhanced CT of the hemodynamically stable patient can provide the IR with useful information about the site of arterial injury. Normalization of intrasplenic Doppler parameters over time indicates that the use of TAE of the splenic artery is a safe adjunct of the nonoperative management of splenic injury. TAE does not prevent formation of sufficient arterial collaterals. Finally, CEUS may compete with CT in follow-up imaging of posttraumatic lesions of the spleen.