Low-dose photon-counting computed tomography improved detection of malignant imaging features and diagnostic confidence while reducing radiation and contrast exposure compared with standard computed tomography in patients with lung cancer.
In a prospective study, researchers evaluated photon-counting computed tomography (PCCT) vs energy-integrating detector computed tomography in 459 patients undergoing contrast-enhanced chest imaging, with 200 patients included after propensity score matching. Patients had pathologically confirmed lung cancer across tumor stages and body mass index categories. PCCT used a lower-dose protocol with ultrahigh-resolution reconstructions down to 0.4 mm, while energy-integrating detector computed tomography (EID CT) used standard-dose imaging. Outcomes included image quality, detection of malignant imaging features, diagnostic confidence, radiation dose, iodine load, adverse reactions and contrast-induced acute kidney injury.
PCCT improved key diagnostic measures while reducing exposure risks. At 0.4 mm resolution, PCCT detected more malignant imaging features than EID CT, with 291 to 340 findings vs 194 to 255 findings, and produced higher diagnostic confidence scores. Overall image quality was also higher, particularly for visualization of structures within enhanced lesions. Radiation exposure decreased by 66% (1.36 mSv vs 4.04 mSv), and iodine load decreased by 27%. Adverse reactions occurred in 2% of patients undergoing PCCT vs 9% with EID CT, and contrast-induced acute kidney injury occurred in 1% vs 7%.
Findings varied across subgroups. Ultrahigh-resolution PCCT (0.4 mm) improved visualization in patients with smaller tumors (≤3 cm) and in normal-weight patients. For larger tumors (>3 cm), 1 mm reconstructions provided better structural delineation than 0.4 mm images, likely reflecting differences in image noise and signal-to-noise characteristics. In patients with higher body mass index, image noise increased and contrast-to-noise ratio decreased, although image quality remained higher than with EID CT.
The study was limited by its single-center design and inclusion of a Chinese population, which may limit generalizability. Imaging parameters differed between groups, and some subgroup analyses, including tumor size comparisons, were conducted post hoc.
“PCCT improved overall image quality, detection of enhancement-related malignant features, and diagnostic confidence,” wrote lead study author Yuhan Zhou, MMed, of the First Affiliated Hospital of Zhengzhou University, and colleagues.
Disclosures: The study was supported by the Key Scientific Research Project of Colleges and Universities in Henan Province. The researchers reported no conflicts of interest.
Source: Radiology
