# Evaluation of assumed tumour volume in multiple myeloma using dual-energy spectral CT and its correlation between haematological findings

## TL;DR

This study uses dual-energy CT to measure tumor volume in multiple myeloma patients and finds a moderate correlation with β2-microglobulin levels.

## Contribution

The novel use of dual-energy spectral CT to extract assumed tumor volume and its correlation with β2-microglobulin in multiple myeloma.

## Key findings

- A moderate correlation was found between assumed tumor volume and β2-microglobulin levels (ρ = 0.69 for single threshold, ρ = 0.57 for double threshold).
- Changes in assumed tumor volume and β2-microglobulin levels after treatment were similar in patients with multiple follow-ups.
- Assumed tumor volume extracted via DESCT shows potential as a biomarker for multiple myeloma.

## Abstract

To measure the assumed tumour volume in the humerus of patients with multiple myeloma using dual-energy spectral computed tomography (DESCT) and to evaluate the correlation with haematological indicators.

We retrospectively analysed 82 DESCT examinations of 22 patients diagnosed with multiple myeloma. After extracting the bilateral humeri and removing the bone tissue, we measured the volume of the assumed tumour area using a single threshold based on Hounsfield unit values and double thresholds using material density images. We analysed the correlations between tumour volume and haematological indicators (β2-microglobulin, M-protein, free light chain, albumin, lactate dehydrogenase) and the trends after treatment intervention.

A moderate correlation was identified between the assumed tumour volume in the initial scan and the β2-microglobulin level, with a correlation coefficient of ρ = 0.69 for the volume calculated from a single threshold value of Hounsfield unit and ρ = 0.57 for the volume calculated from a double threshold value of the bone(fat) material density image. No significant correlation was found between the assumed tumour volume and the M-protein or free light chain levels. In patients who underwent three or more follow-up evaluations after the initial examination, there was a similarity in the changes in the assumed tumour volume and β2-microglobulin levels after treatment.

Extracting assumed tumour volume using DESCT has sufficient potential as a biomarker for multiple myeloma.

•Extraction of assumed tumour volume of multiple myeloma using dual energy CT.•Assumed tumour volume and β2 microglobulin level has a moderate correlation.•Trends in assumed tumour volume and β2 microglobulin level after treatment are similar.•Assumed tumour volume has sufficient potential as a biomarker for multiple myeloma.

Extraction of assumed tumour volume of multiple myeloma using dual energy CT.

Assumed tumour volume and β2 microglobulin level has a moderate correlation.

Trends in assumed tumour volume and β2 microglobulin level after treatment are similar.

Assumed tumour volume has sufficient potential as a biomarker for multiple myeloma.