Objective: We tested breath-held 1-mm multislice helical CT for obtaining both contiguous and high-resolution CT sections of the chest from a single set of raw data.
Subjects and methods: Seventy patients with suspected focal and diffuse lung disease were allocated into two groups for comparison. The first group (n = 35) underwent multislice helical CT of the chest with 1-mm collimation and a pitch of 6. From the raw data, 5-mm contiguous and 1.25-mm high-resolution CT sections were reconstructed. The second group (n = 35) underwent conventional single-slice helical CT and high-resolution CT. High-resolution CT sections and 5-mm scans were rated for overall image quality, spatial resolution, subjective signal-to-noise ratio, diagnostic value, depiction of bronchi and parenchyma, and motion and streak artifacts. The 5-mm scans were also rated for contrast resolution and depiction of the heart and vessels. Radiation dose was calculated.
Results: We rated 5-mm multislice helical CT superior to 5-mm single-slice helical CT, having a significantly higher total score (p = 0.0001). No significant difference (p = 0.986) was found between multislice and single-slice high-resolution CT sections. Radiation dose was 5.55 mSv for multislice helical CT and 5.50 mSv for single-slice helical CT.
Conclusion: Contiguous chest scans of superior quality and high-resolution CT sections of equal image quality compared with single-slice helical CT can be obtained using multislice helical CT. Therefore, a comprehensive diagnosis is feasible in patients with suspected focal and diffuse lung disease by obtaining a single scan.