Diagnostic accuracy of low-dose and ultra-low-dose CT in detection of chest pathology: a systematic review

Purpose: Studies have evaluated imaging modalities with a lower radiation dose than standard-dose CT (SD-CT) for chest examination. This systematic review aimed to summarize evidence on diagnostic accuracy of these modalities ? low-dose and ultra-low-dose CT (LD- and ULD-CT) ? for chest pathology. Method: Ovid-MEDLINE, Ovid-EMBASE and the Cochrane Library were systematically searched April 29th?30th, 2019 and screened by two reviewers. Studies on diagnostic accuracy were included if they defined their index tests as ?LD-CT?, ?Reduced-dose CT? or ?ULD-CT? and had SD-CT as reference standard. Risk of bias was evaluated on study level using the Quality Assessment of Diagnostic Accuracy Studies-2. A narrative synthesis was conducted to compare the diagnostic accuracy measurements. Results: Of the 4257 studies identified, 18 were eligible for inclusion. SD-CT (3.17 ? 1.47 mSv) was used as reference standard in all studies to evaluate diagnostic accuracy of LD- (1.22 ? 0.34 mSv) and ULD-CT (0.22 ? 0.05 mSv), respectively. LD-CT had high sensitivities for detection of bronchiectasis (82?96%), honeycomb (75?100%), and varying sensitivities for nodules (63?99%) and ground glass opacities (GGO) (77?91%). ULD-CT had high sensitivities for GGO (93?100%), pneumothorax (100%), consolidations (90?100%), and varying sensitivities for nodules (60?100%) and emphysema (65?90%). Conclusion: The included studies found LD-CT to have high diagnostic accuracy in detection of honeycombing and bronchiectasis and ULD-CT to have high diagnostic accuracy for pneumothorax, consolidations and GGO. Summarizing evidence on diagnostic accuracy of LD- and ULD-CT for other chest pathology was not possible due to varying outcome measures, lack of precision estimates and heterogeneous study design and methodology.