What is LOCAT?

"Low-dOse CT of Appendicitis Trial"

Background

Computed tomography (CT) radiation is arguably carcinogenic. Single-center studies, mostly retrospective, have advocated lowering the CT radiation dose for the diagnosis of appendicitis. However, the adoption of low-dose CT is slow. The effectiveness of low-dose CT compared to standard-dose CT has not been studied in a pragmatic multicenter setting. This was the aim of LOCAT.

Objectives

• To determine whether low-dose CT (2 mSv) is non-inferior to standard-dose CT (8 mSv or lower) for important clinical outcomes.

• To confirm the generalizability of the previous single-center study.

• To disseminate the use of the low-dose CT practice across the participating sites through the implementation of the study protocol.

Hypothesis

• Low-dose CT is non-inferior to standard-dose CT regarding negative appendectomy rate in adolescents and young adults.

Study design

• Multi-center, pragmatic, non-inferiority, assessor and patient blinded, parallel-group, randomized trial.

Eligibility criteria

• 15 to 44 years in age, who underwent CT for suspected appendicitis.

Primary endpoint

• The primary endpoint was negative appendectomy rate. Negative appendectomy indicates the removal of the uninflamed appendix. Negative appendectomy rate was defined as the percentage of negative appendectomies (unnecessary removal of uninflamed appendix) out of all appendectomies.

Scale

• 20 sites in South Korea.

• 3074 patients.

• More than 500 care providers (including 161 radiologists).

• 22 CT machines.

Study period

• From Dec 4, 2013 through Aug 18, 2016.

Study results

• Low-dose CT for the Diagnosis of Appendicitis in Adolescents and Young Adults (LOCAT) a Pragmatic Multicenter Non-inferiority Randomized Controlled Trial.

ClinicalTrials.gov Identifier:

• NCT01925014

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