Comparison of the use of lung ultrasound and chest radiography in the diagnosis of rib fractures: a systematic review

Roshani Patel, MS4

Article: Battle C, et al. Comparison of the use of lung ultrasound and chest radiography in the diagnosis of rib fractures: a systematic review. Emergency Medical Journal (2018), http://dx.doi.org/10.1136/emermed-2017-207416

Background: Rib fractures are the most frequent blunt chest trauma and are associated with complications such as pneumothorax and lung contusion.  Prognosis from blunt trauma is complicated by the fact that up to 50% of rib fractures are missed on chest radiograph. However despite this limitation, chest radiograph remains the primary modality for diagnosis. The American College of Radiology has recently revised its appropriateness criteria and now states that it is unnecessary to perform chest radiography for rib fractures in adults with minor trauma.  Lung ultrasound has recently been studied for its use in identifying rib fractures after blunt chest wall trauma. When compared against standard radiography, lung ultrasound has been found to be superior. This paper seeks to identify whether or not lung ultrasound is superior in accuracy to chest radiographs in the diagnosis of rib fractures after blunt chest wall trauma 

The Study/Methods: This was a systematic review. A total of 4317 titles/abstracts were  found that matched they key words used, however after screening  only 13 articles were included in the review. All studies were single center, with variable number of patients ( 5-201).

Inclusion criteria:

  • Population: adults 16 yo or older, patients with blunt chest wall trauma, undergoing both radiological and ultrasound investigation

  • Interventions/Exposures: lung ultrasound

  • Comparison: chest radiograph

  • Study design: observational studies

Exclusion criteria:

  • Population: patients with penetrating trauma only, patients with multi-trauma only and no reference to chest trauma, patients with intra-thoracic injuries only and no chest wall trauma, children (under 16 y/o)

  • Intervention:: no lung ultrasound included

  • Comparison: no chest radiograph included

  • Study design: review articles, letters/editorials, case studies, case-control series

Results: The patient population the studies assessed were trauma patients presenting to the ED. In 11 of these studies (85%), LUS was reported to identify a higher proportion of patients with rib fractures than chest radiograph.  In two studies, it was reported that a certain number of rib fractures were seen on chest radiograph but missed on LUS.

Takeaway: LUS was superior to chest radiograph for various reasons, some of those reasons being that ultrasound is unaffected by respiratory motion, leads to reduction in exposure to radiation, results can be immediately interpreted, ultrasound machine is portable, and it can be used by anyone, even non-radiologists.  Drawbacks to using ultrasound to diagnosis rib fractures include that the process can be painful for the patient, in some studies it was reported that the retroscapular and infraclavicular portions of the first rib were not able to be assessed, the process can be time-consuming, and finally obesity and large breasts also serve as limitations to obtaining accurate images. As of now, CT is generally agreed to be the gold standard to diagnosis rib fractures, studies directly comparing CT Scan to LUS need to be completed.