High performance of low/ultralow-dose photon-counting CT for pulmonary metastasis in young musculoskeletal malignancy patients

Purpose

To investigate the performance of chest photon-counting CT (PCCT) at low-dose (LD) and ultralow-dose (ULD) in young musculoskeletal malignancy patients with pulmonary metastasis and compare with prior standard-dose energy-integrating CT (EICT).

Materials and methods

From August to November 2023, this prospective study recruited consecutive participants with prior EICT images and grouped them into LD and ULD groups to receive PCCT examination. Two observers independently and blindly evaluated the image quality using a five-point Likert scale. Intraindividual differences between PCCT and EICT were compared using the Wilcoxon signed-rank test or paired samples t-test.

Results

The LD and ULD groups included 50 (19 [16; 21] years; 33 males) and 50 participants (19 [14; 21] years; 30 males), respectively. The interval between EICT and PCCT examinations was 116 (88.5; 194) days. Compared with EICT, PCCT obtained median effective dose reduction rates of 87.62 % (3.78 [3.15; 5.18] vs. 0.43 [0.39; 0.58] mSv; p < 0.001) and 92.58 % (3.92 [2.96; 4.95] vs. 0.27 [0.22; 0.34] mSv; p < 0.001) in the LD and ULD groups, respectively. For subjective assessments, PCCT has superior overall image quality (5 [5; 5] vs. 5 [4; 5]) and lung nodule visualization (5 [5; 5] vs. 5 [4; 5]) to EICT (all p-values <0.001).

Conclusion

PCCT provided higher image quality and lung nodule visualization with significant dose reduction compared to EICT in these young musculoskeletal malignancy patients.