MRI Metrics May Improve Early Bone Metastasis Assessment

DIFFUSION-WEIGHTED IMAGING (DWI) combined with conventional response criteria may improve early assessment of pelvic bone metastases in patients with lung cancer, according to a pilot study that found gains in response classification when quantitative imaging measures were incorporated.

Integrating DWI With Conventional Response Criteria

Researchers retrospectively assessed 78 pelvic bone lesions in 27 patients with lung cancer who underwent three magnetic resonance imaging (MRI) examinations between November 2015 and November 2023.

Scans were obtained at baseline, at an early time point within 4 months of treatment, and at a later time point between 6 and 15 months.

Researchers investigated whether apparent diffusion coefficient (ADC) measurements derived from DWI could provide complementary information to the Response Evaluation Criteria in Solid Tumours (RECIST) 1.1.

A DWI response was defined as an ADC value greater than 1,300 µm²/s or an ADC change greater than 0.14.

Improved Early Response Classification

The researchers compared early response assessments using RECIST alone and DWI-RECIST, using the later RECIST assessment as the reference standard. DWI-RECIST produced net classification gains of 7.4% for the first reader and 11.1% for the second reader.

The integrated approach also achieved higher area under the curve (AUC) values than RECIST alone for both readers.

Agreement between readers for ADC measurements was good, with intraclass correlation coefficient values ranging from 0.83 to 0.86. This indicated consistency in the quantitative measurements obtained by the two readers.

Further Evaluation Is Needed

The findings suggest that incorporating DWI-derived measurements may provide additional information when assessing treatment response in pelvic bone metastases from lung cancer, particularly for lesions classified as stable disease using conventional criteria.

Researchers concluded that DWI-RECIST could support a more objective approach to early response assessment. The pilot study also proposed quantitative ADC thresholds for integrating functional imaging with conventional response criteria.

However, the findings require further evaluation before the approach can be established for routine clinical use. Results provide preliminary evidence that quantitative MRI measures may complement lesion size assessment when monitoring treatment response in patients with lung cancer and pelvic bone metastases.

Reference:

Park H et al. Integrating DWI parameters with RECIST 1.1 for early assessment of systemic therapy response in lung cancer pelvic bone metastases. Br J Radio. 2026;DOI:10.1093/bjr/tqag249.