A quality improvement project addressing motion artefact on CTPAs in a district general hospital setting: A complete cycle resulting in changed practice.

Sammendrag

Introduction: A still breath hold from the patient is one of the key requirements for a diagnostic computed tomography pulmonary angiogram (CTPA). It is important for the timely identification and treatment of patients with life threatening pulmonary emboli (PEs). Motion artefact on CTPA can cause blurring, double borders, shading and streaking in the lungs, which can either obscure PEs or create artefact that mimics PEs. This risks patient harm from delayed diagnoses, missed PEs, false positives and extra radiation and contrast exposure due to repeat studies.

Methods: We devised local standards and methodology for assessing the presence and degree of motion artefact on CTs. The study consisted of initial data collection, implementation of changes to clinical practice, and subsequent repeat data collection 3 months after implementation of interventions. For each data collection round, 100 consecutive inpatient and emergency CTPAs performed in a UK District General Hospital were retrospectively identified and images reviewed to categorise each as having either: ‘no significant’, ‘minor’ or ‘major’ motion artefact. There were no exclusions. Interventions after initial data collection included a multidisciplinary meeting with radiographers, department assistants, and radiologists to devise changes to workflow and practices to build in 'rehearsal' of a breath-hold and explanation of breathing instructions with patients before scanning. A prompting phrase for this was added to our CTPA scanning protocol.

Results: Initial results demonstrated that 50% of CTPA showed either minor or major motion artefact, while 50% showed no significant motion artefact. For 2% with minor motion, a clinical reason for why this was unavoidable was provided. Therefore 52% of studies met the proposed local standards. In total, 45% of CTPA were assessed to have minor motion and 5% had major motion artefact (non-diagnostic). 18% of CTPA were positive for PE. Following implementation of changes to practice, repeat data collection demonstrated that 67% of CTPA showed no significant motion artefact. 3% with minor motion provided a clinical reason why this was unavoidable. Therefore 70% of studies met the proposed standard. The increase in compliance with local standards was statistically significant (p=0.00906).

Conclusion: Our interventions improved compliance with local standards from 52% to 70%. We recommend rehearsal of breath-holding with patients before CTPA scans as a quick and easy way to improve the diagnostic quality of scans. A prompting phrase within the CTPA scanning protocol has proven effective.