Ultralow-Dose Chest CT Outperforms X-Ray in Emergency Department Patients

By MedImaging International staff writers
Posted on 25 Oct 2023

Image: A study has found ultralow-dose chest CT to be superior to X-ray in emergencies (Photo courtesy of 123RF)

Chest X-rays are a commonly used primary diagnostic tool for various medical conditions, offering benefits like easy access, quick results, and minimal radiation exposure. However, they don't score high in terms of sensitivity and specificity. Chest CT scans offer better diagnostic capabilities but come with drawbacks like higher radiation, more expense, and longer time for reports. Advances in CT technology, however, may be turning the tide. Now, a new study has found that ultralow-dose chest CT has twice the detection rate for main diagnoses compared to chest X-rays in patients who visit the emergency room for non-traumatic issues. The finding suggests that CT scans could be used more commonly as an assessment tool for these patients.

Traditionally, non-contrast-enhanced chest CTs are carried out at two key radiation dose levels: standard-dose and low-dose CT. But the latest improvements in CT technology, such as new detectors and reconstruction algorithms, have dramatically reduced the necessary radiation exposure for chest CTs. It's now nearly equivalent to that of a chest X-ray. As a result, ultralow-dose chest CT is emerging as a viable alternative to standard chest X-rays for patients with low prevalence conditions. Numerous studies have already indicated the effectiveness of using chest CTs with radiation doses up to that of three chest X-rays.

Researchers from the Medical University of Vienna (Vienna, Austria) investigated how ultralow-dose chest CT might offer advantages over chest X-rays for emergency room patients with non-traumatic issues. The study involved 294 participants who visited the emergency room between May and November of 2019. All subjects received both a chest X-ray and an ultralow-dose CT scan. The study was segmented into two groups based on these diagnostic methods. The research showed that ultralow-dose chest CT provided over double the rate of main diagnoses compared to chest X-rays. While this indicates that ultralow-dose CT could serve as a primary imaging method for non-traumatic emergency room patients, more research is essential. This is particularly true considering that CT scans are more expensive and take longer to report, the researchers noted.

"Our findings support the future use of ultralow-dose CT as one of the primary chest-imaging modalities in low-prevalence non-traumatic emergency department patients," wrote the researchers. "Due to higher expected costs and resource requirements, further economic analyses will be necessary to determine the optimal spectrum of indications, rationale, and economic potential of a broader substitution of ultralow-dose CT for chest X-ray as a primary imaging modality of the chest."

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Medical University of Vienna