Improved assessment of mediastinal and pulmonary pathologies in combined staging CT examinations using a fast-speed acquisition dual-source CT protocol.

OBJECTIVES: To demonstrate the feasibility of fast Dual-Source CT (DSCT) and to evaluate the clinical utility in chest/abdomen/pelvis staging CT studies.

METHODS: 45 cancer patients with two follow-up combined chest/abdomen/pelvis staging CT examinations (maximally ±10 kV difference in tube potential) were included. The first scan had to be performed with our standard protocol (fixed pitch 0.6), the second one using a novel fast-speed DSCT protocol (fixed pitch 1.55). Effective doses (ED) were calculated, noise measurements performed. Scan times were compared, motion artefacts and the diagnostic confidence rated in consensus reading.

RESULTS: ED for the standard and fast-speed scans was 9.1 (7.0-11.1) mSv and 9.2 (7.4-12.8) mSv, respectively (P = 0.075). Image noise was comparable (abdomen; all P > 0.05) or reduced for fast-speed CTs (trachea, P = 0.001; ascending aorta, P < 0.001). Motion artefacts of the heart/the ascending aorta (all P < 0.001) and breathing artefacts (P < 0.031) were reduced in fast DSCT. The diagnostic confidence for the evaluation of mediastinal (P < 0.001) and pulmonary (P = 0.008) pathologies was improved for fast DSCT.

CONCLUSIONS: Fast DSCT for chest/abdomen/pelvis staging CT examinations is performed within 2 seconds scan time and eliminates relevant intrathoracic motion/breathing artefacts. Mediastinal/pulmonary pathologies can thus be assessed with high diagnostic confidence. Abdominal image quality remains excellent.

KEY POINTS: • Fast dual-source CT provides chest/abdomen/pelvis staging examinations within 2 seconds scan time. • The sevenfold scan time reduction eliminates relevant intrathoracic motion/breathing artefacts. • Mediastinal/pulmonary pathologies can now be assessed with high diagnostic confidence. • The coverage of the peripheral soft tissues is comparable to single-source CT. • Fast and large-volume oncologic DSCT can be performed with 9 mSv effective dose.