American Journal of Roentgenology最新文献

Despite growing clinical use of contrast-enhanced ultrasound (CEUS), inconsistency remains in the modality's role in clinical pathways for hepatocellular carcinoma (HCC) diagnosis and management. This AJR Expert Panel Narrative Review provides practical insights on the use of CEUS for the diagnosis of HCC across populations, including individuals at high risk for HCC, individuals with metabolic dysfunction-associated steatotic liver disease, and individuals not at high risk for HCC. Considerations addressed with respect to high-risk patients include CEUS diagnostic criteria for HCC, use of CEUS for differentiating HCC from non-HCC malignancy, use of CEUS for small (≤ 2 cm) lesions, use of CEUS for characterizing occult lesions on B-mode ultrasound, and use of CEUS for indeterminate lesions on CT or MRI. Representative literature addressing the use of CEUS for HCC diagnosis and gaps in knowledge requiring further investigation are highlighted. Throughout these discussions, the article distinguishes two broad types of ultrasound contrast agents used for liver imaging: pure blood-pool agents and a combined blood-pool and Kupffer-cell agent. Additional topics include the use of CEUS for treatment response assessment after nonradiation therapies and implications of artificial intelligence technologies. The article concludes with a series of consensus statements from the author panel.

Concerns about the risk of radiation from CT have driven a spectrum of major advances in radiation dose reduction technology since the 2000s, including added beam filtration, dynamic z-axis collimation, automatic tube current modulation and tube potential selection, advanced iterative reconstruction, and deep learning-based reconstructions. The introduction of photon-counting detector CT further improved dose efficiency through electronic noise rejection, optimal photon-energy weighting, and high-resolution data acquisition. This Review summarizes key milestones and technologic innovations that have led to substantial reductions in CT radiation doses and provides examples of the cumulative impact of these advances on CT doses and image quality for routine examinations in various anatomic sites. This article also highlights the importance of an objective task-based image quality assessment to ensure that diagnostic performance is not compromised as dose is reduced, particularly for emerging deep-learning-based reconstruction and postprocessing noise reduction methods.

Background: Digital breast tomosynthesis (DBT) has shown improved screening performance compared to digital mammography (DM), although the modality is less well-studied in women 40-44 or ≥75 years old. Objective: To compare screening performance between DM and DBT in Tomosynthesis Mammographic Imaging Screening Trial (TMIST) Lead-in trial (A4705) participants who were ineligible for transition to the full TMIST trial (EA1151) due to age at trial entry (40-44 or ≥75 years old). Methods: A4705, a prospective trial recruiting women ≥40 years old at four Canadian sites from October 2014 to July /2017, randomized participants to undergo multiple screening rounds by DM or DBT. Final EA1151 eligibility incorporated a narrower age range of 45-74 years. This unplanned analysis included a subset of A4705 participants ineligible for transition to EA1151 due to age at entry (40-44 or ≥75 years old). Examination-level screening performance metrics were calculated. The reference standard was determined by 1-year follow-up after participants' last screening round. Results: The study included 271 A4705 participants (mean age, 54±17 years) age-ineligible for EA1151; 181 were 40-44 years old (76 and 105 randomized to DM and DBT, respectively), and 90 were ≥75 years old (46 and 44 randomized to DM and DBT, respectively). Participants in the DM and DBT arms underwent 389 and 482 screening examinations, respectively (mean, 3.2 screening rounds per participant in each arm). Eight cancers were diagnosed (7 screen-detected [1 by DM; 6 by DBT]; one interval cancer in DBT arm). In participants 40-44 years old, DM, compared with DBT, exhibited recall rate of 13.2% versus 12.0%, cancer detection rate (CDR) per 1000 of 0.0 versus 14.6, PPV1 of 0.0% versus 12.2%, and PPV3 of 0.0% versus 83.3%, respectively. In participants ≥75 years old, DM, compared with DBT, exhibited recall rate of 10.1% versus 3.6%, CDR per 1000 of 7.2 versus 7.1, PPV1 of 7.1% versus 20.0%, and PPV3 of 50.0% in both arms. Conclusion: Screening performance metrics were overall more favorable for DBT than for DM in women 40-44 years or ≥75 years old. Clinical Impact: DBT may mitigate limitations of DM and improve screening performance in the evaluated age groups.