Clinical Scorecard: Impact of Lesion Dimensions on Navigator-Triggered versus Free-Breathing Diffusion-Weighted MRI of the Liver

At a Glance

Key Highlights

• Breathing and cardiac motion cause artifacts in liver DWI, especially in the left liver lobe near the heart.
• Navigator-triggered (TRIG) acquisition adapts image acquisition to respiration, reducing motion artifacts but extending scan time.
• Free-breathing (FB) acquisition allows more data acquisition in the same time, increasing signal-to-noise ratio but may cause blurring or lesion misregistration.

Guideline-Based Recommendations

Diagnosis

• Use DWI MRI to assess extent of liver involvement in tumor disease.
• Exclude likely benign lesions (e.g., cysts, hemangiomas) using clinical MRI datasets including T2w and contrast-enhanced T1w images.

Management

• Choose between FB and TRIG acquisition based on lesion size and patient cooperation.
• Consider TRIG acquisition for better detection of smaller lesions due to reduced motion artifacts.

Monitoring & Follow-up

• Evaluate lesion conspicuity and contrast-to-noise ratio (CNR) in both FB and TRIG images.
• Monitor acquisition times and image quality to ensure diagnostic reliability.

Risks

• FB acquisition may cause lesion blurring and misregistration due to motion artifacts.
• TRIG acquisition may prolong scan time unpredictably and requires patient tolerance of longer exam.

Patient & Prescribing Data

Adult patients with known or suspected focal liver lesions undergoing MRI

TRIG acquisition may improve detection of smaller lesions; FB acquisition is more time-efficient but may compromise image quality in small lesions.

Clinical Best Practices

• Use navigator-triggered DWI for patients where small lesion detection is critical and patient can tolerate longer scan times.
• Employ free-breathing DWI for patients with limited ability to cooperate or when time efficiency is prioritized.
• Segment lesions on b=800 s/mm2 images and confirm lesion characterization with full clinical MRI datasets.
• Exclude benign lesions based on clinical reports and multimodal imaging to focus on malignant or suspicious lesions.

References

• Choi et al study on lesion detection and characterization
• Takayama et al on lesion contrast-to-noise ratio
• Szklaruk et al on image quality with TRIG
• Nasu et al on lesion contrast and misregistrations
• Prior study on small FLL detection with TRIG acquisition