For patients with metabolic dysfunction-associated steatotic liver disease (MASLD), new research demonstrates the use of photon-counting detector computed tomography (PCD CT) can provide CT-derived fat fraction (CTFF) evaluation that is a consistently comparable alternative to magnetic resonance imaging (MRI)-derived proton density fat fraction (PDFF) assessment.
For the prospective study, recently published in Radiology, compared CTFF and PDFF in 412 asymptomatic study participants and 122 participants with MASLD. To estimate CTFF, the researchers utilized a CT to MRI fat quantification formula that originated with a training cohort of 53 asymptomatic study participants who had a CT with a standard 120-kVp radiation dose.
The researchers found a 94 percent interclass correlation coefficient (ICC) between CTFF and PDFF for asymptomatic study participants, and a 96 percent ICC in the cohort of participants with MASLD.
In subgroup analyses, the study authors noted the ICC remained between 93 and 94 percent across tube voltages ranging from 90 to 140 kVp. The study authors also no significant differences in the ICC between low and standard radiation dosing (95 percent vs. 93 percent).
“PCD CT matched the overall performance of MRI and exhibited minimal bias—independent of tube voltage, radiation dose, body mass index, and proton density fat fraction. This study demonstrates that PCD CT can be used to reliably report liver fat content as a continuous percentage across various settings,” wrote lead study author Hulmin Lin, M.D., who is affiliated with the Department of Radiology at Ruijin Hospital and the Shanghai Jiao Tong University School of Medicine in Shanghai, China, and colleagues.
Three Key Takeaways
1. Comparable to MRI. PCD CT provides a reliable alternative to MRI for evaluating liver fat content, showing a 94-96 percent correlation with MRI-derived proton density fat fraction (PDFF) in both asymptomatic patients and those with MASLD.
2. Consistency across settings. The accuracy of PCD CT remains consistent across various radiation doses (standard and low) and tube voltages, making it adaptable for different clinical settings.
3. Advantages over traditional CT. PCD CT reduces the limitations seen with conventional CT, such as beam hardening and dose variability, by accurately measuring individual photon energies, improving radiation efficiency and image stability.
Noting limitations with traditional energy-integrating detector CT (EID CT) for assessing hepatic steatosis quantification, including shifting CT values due to low-dose settings and beam hardening related to body habitus, the researchers suggested that photon-counting CT can provide a viable alternative.
“The key advantage of PCD CT is that it allows accurate determination of effective beam energy via direct measurement of individual photon energies, contributing to high radiation dose efficiency. Energy thresholds further eliminate electronic noise, enhancing the stability of CT values in both large-habitus and low-dose settings,” explained Lin and colleagues.
(Editor’s note: For related content, see “Could Photon Counting CT Supplant MRI for Imaging Assessment of Hepatic Steatosis?,” “FDA Clears AI Software for Liver Attenuation on Abdominal CT” and “Can Deep Learning Enhance Ultrasound Assessment of Hepatic Steatosis in Patients with NAFLD?”)
In regard to study limitations, the authors acknowledged that the interval between CT and MRI examinations in the study could be as high as one month. While the PCD CT value demonstrated accuracy in the cohort of patients with MASLD, the researchers conceded that further research is necessary to examine accuracy with other coexisting liver diseases that can affect liver parenchyma attenuation.
