Simon Voorhees, MS4
The Article: Zhang Z, Hong Y, Liu N, Chen Y (2017) Diagnostic accuracy of contrast enhanced ultrasound in patients with blunt abdominal trauma presenting to the emergency department: a systematic review and meta-analysis. Sci Rep 7:4446.
The Idea:
Trauma is a leading cause of mortality in the young adult population; ultrasound has been used to great effect in blunt abdominal trauma to identify hemoperitoneum in hemodynamically unstable patients, however traditional ultrasound is notably not sensitive for identifying parenchymal injuries. This meta-analysis compares the ability of contrast-enhanced ultrasound (CEUS) to identify soft tissue injuries against the gold standard of CT scan in the setting of blunt abdominal trauma presenting to the emergency department.
The Study:
This study was a meta-analysis looking at studies fulfilling the following criteria:
1) Human studies investigating diagnostic accuracy of CEUS in setting of blunt abdominal trauma
2) Prospective and retrospective studies eligible
3) Reference standard clearly defined
Exclusion Criteria:
1) Animal Studies
2) Follow up studies investigating recovery of injured organs
3) Reviews and commentary
4) Duplicated reports
5) Studies investigating luminal organs (intestine, gall bladder, etc.)
6) Non-trauma conditions
The initial search yielded 421 citations; using the aforementioned parameters 10 studies were eligible (9 of which were included for quantitative analysis). These studies are also assessed using the QUADAS tool to determine the potential for bias. Data that was collected from these studies included true positives, false positives, true negatives, and false negatives.
Results:
The combined log diagnostic odds ratio (DOR) across studies was 6.56 (95% CI 5.66-7.45). Sensitivity pooled across 17 data sets was 98.1% with a false positive rate of 1.8%. For spleen, sensitivity was 90.4% with false positive rate of 2.8%, for liver 94.1% and 1.1%, and for kidney 91.0% and 1.1%,
Takeaway:
In hemodynamically stable patients with a history of low-energy (mild to moderate) blunt abdominal trauma CEUS is an appropriate measure for identifying parenchymal injury (liver, spleen, kidneys) with sensitivity and specificity approaching that of CT. In the context of blunt abdominal trauma, delayed hemorrhage is common and repeat evaluations with CEUS may have high utility while sparing exposure to ionizing radiation. Limitations include evaluation of deep organs and small organs such as the adrenal glands (in one study two adrenal lesions were missed that were detected on CT scan). There is a small amount of data demonstrating possible utility for detecting pancreatic injury as well, however the quality is low and there is limited data on false positive rates.