Researchers in Beijing identified a new ultrasound feature called perfusion beyond margin that can predict more aggressive hepatocellular carcinoma and worse patient outcomes. The feature, measured through contrast-enhanced ultrasound, shows how far a tumor's blood flow extends beyond its visible edge, and patients with this feature had significantly worse survival rates after surgery or ablation treatment.
- Perfusion beyond margin (PBM) is defined as arterial-phase blood flow extending 5 mm or more beyond a tumor's visible margin on contrast-enhanced ultrasound
- Patients with PBM had 1.76 times worse recurrence-free survival after surgery and 2.40 times worse local tumor progression-free survival after thermal ablation
- PBM tumors showed higher rates of microvascular invasion (52.2% vs 25.0%) and aggressive cellular markers, indicating more invasive disease
- The feature is highly reproducible—clinicians without prior ultrasound experience achieved 92% accuracy after just two hours of training
- PBM provides a simple, clinically applicable imaging biomarker that integrates imaging findings with tumor biology and patient prognosis
A research team in Beijing, China, has introduced a new ultrasound feature that could help guide treatments for patients with hepatocellular carcinoma (HCC), according to a study published October 6 in Radiology.
Identified through contrast-enhanced ultrasound (CEUS), so-called "perfusion beyond margin" is a measurement of how far a tumor's blood flow extends beyond its morphological margin, with findings suggesting the feature can identify patients with more aggressive disease.
"Perfusion beyond margin is a new imaging feature that was effectively identified through contrast-enhanced US of patients with hepatocellular carcinoma and was associated with greater invasive potential and poorer prognosis," wrote lead authors Wenzhen Ding, MD, and Ran Ji, MD, of the Chinese PLA General Hospital, and colleagues.
Previous imaging studies have shown inconsistency between a tumors vascularity and gross morphologic features, but no prior research had clearly defined this phenomenon or analyzed its clinical influence, according to the group. CEUS can depict both features simultaneously within the same image frame, which hypothetically could allow clinicians to measure the discrepancy.
In this study, the group defined perfusion beyond margin (PBM) as the arterial-phase diameter (perfusion) exceeding gray-scale ultrasound (margin) by 5 mm and analyzed its significance in 1,076 patients with HCC. The primary outcomes were recurrence-free survival after laparoscopic hepatectomy and local tumor progression-free survival after thermal ablation.
Tumor diameter measurement. The measurement of tumor diameter was divided into three steps: (a) obtain hepatocellular carcinoma (HCC) image; (b) measure HCC diameter in gray-scale US image; (c) fine-tune the measurement markers on contrast-enhanced US (CEUS) image to measure HCC. In a 62-year-old man with cirrhosis, after injection of contrast agent, the tumor diameter was determined to be 19 mm initially in the gray-scale US image (left column: white cross), but this was modified to 23 mm on the CEUS image (right column: white cross).RSNA
"This study provided a clinically applicable, reproducible feature that integrates imaging, biology, and prognosis," the group wrote.
In an accompanying editorial, Omid Shafaat, MD, and Stephen Reis, MD, both of Columbia University in New York City, noted that in the study, five readers without prior CEUS experience reached 92% classification accuracy when measuring PBM after just two hours of training, and that the findings held steady across different acquisition angles and time points.
"That reproducibility is crucial. Many imaging biomarkers stall in the laboratory because they rely on tedious segmentation, registration, or complex postprocessing," they wrote.
PBM offers a potentially simple imaging window into the biologic behavior of HCC tumors and, if prospectively validated, may eventually help bridge tumor characterization and image-guided therapy, Shafaat and Reis concluded.
The full study is available here.
