Efficacy Validation of a Novel MRI-Based Whole-Body Rapid Bone Scan (WB-RBS) Strategy for Diagnosing Bone Metastases: A Prospective Trial

Background

Traditional bone scintigraphy for detecting malignant bone metastases is limited by suboptimal accuracy and radiation exposure. Whole-body magnetic resonance imaging (WB-MRI), while an alternative, requires lengthy scan times and high patient compliance.

Purpose

To develop a novel, rapid whole-body bone screening (WB-RBS) MRI protocol and evaluate its diagnostic performance for bone metastasis detection.

Materials and Methods

Patients with pathologically confirmed malignancies and healthy controls were prospectively enrolled. All participants underwent WB-RBS (acquisition time: about 10 min); patients additionally underwent WB-MRI (about 70 min). Three radiologists, blinded to clinical data, independently evaluated the images for bone metastases. A consensus expert diagnosis served as the reference standard to calculate the diagnostic performance of WB-RBS. Specificity was further assessed in the healthy control group.

Results

Seventy patients and 19 healthy controls were included. WB-RBS demonstrated excellent inter-reader agreement at the patient level. Compared with the reference standard, WB-RBS achieved an accuracy of 77.1%–91.4% at the patient level and a slightly lower accuracy (70.6%–82.5%) at the lesion level. At diagnostic confidence thresholds 1–3, the correlations between WB-RBS ratings and the reference standard were statistically significant for both patient- and lesion-level analyses.

Conclusion

WB-RBS showed favorable inter-reader agreement and high accuracy for bone metastasis screening at the patient level, while substantially reducing scan time and cost. Its rapid, radiation-free nature and high accessibility offer distinct clinical advantages, supporting its potential as an alternative screening tool to conventional bone scintigraphy.

Summary

For patients requiring assessment of bone metastases, the WB-RBS protocol provides a rapid (about 10-min), radiation-free, and accurate diagnostic option that facilitates clinical decision-making and enhances patient comfort.

Key Points

• This study addresses the clinical need for a fast, accurate, and radiation-free bone metastasis screening tool by proposing a novel whole-body MRI-based screening strategy, which overcomes the limitations of conventional bone scintigraphy and reduces the lengthy acquisition time associated with standard WB-MRI.

• The approximately 10 minutes WB-RBS protocol developed demonstrated high diagnostic performance in detecting bone metastases in cancer patients, with favorable diagnostic accuracy.

• The protocol exhibits outstanding diagnostic capability for long bones of limbs and lesions larger than 1.5 cm in diameter, providing a practical and efficient imaging tool for identification and localization of bone metastases.