Comparison of 3T diffusion-weighted MRI and F-FDG PET/CT in musculoskeletal tumours: quantitative analysis of apparent diffusion coefficients and standardized uptake values.

OBJECTIVE

To determine whether the apparent diffusion coefficient (ADC) on 3T MR imaging including diffusion-weighted MR imaging (DWI) correlate with the standardized uptake value (SUV) on 18F-FDG PET/CT in musculoskeletal tumours.

METHODS

This retrospective cohort study included 57 patients (36 males, 21 females, mean age 54 years, range 12-90 years) with pathologically confirmed soft tissue ( = 32) and bone ( = 25) tumours who underwent 3T MR imaging including DWI and whole-body 18F-FDG PET/CT before treatment. 14 patients had follow-up MR imaging and 18F-FDG PET/CT after treatment. The minimum (ADC) and mean (ADC) ADCs of musculoskeletal tumour, ADC of normal skeletal muscle (ADC), SUV and SUV of musculoskeletal tumour were obtained. Correlation between ADCs and SUVs was assessed using Pearson correlation coefficients (r). ADC and SUV were compared between pretreatment and posttreatment by t-test.

RESULTS

There was inverse correlation between SUV and the ratio ADC/ADC ( = - 0.505 to - 0.495, ≤ 0.001) and between SUV and the ratio ADC/ADC ( = - 0.501 to - 0.493, = 0.001). After treatment ADC was significantly increased whereas SUV was significantly decreased ( = 0.001). There was significant correlation in percent change between the initial and follow-up values of ADC and SUV ( = 0.750 to 0.773, ≤ 0.005). The ADC was increased by 163% and SUV was decreased by 61% in 11 patients with treatment response.

CONCLUSION

ADC at 3T MR DWI and SUV at 18F-FDG PET/CT have an inverse correlation in musculoskeletal tumours.

ADVANCES IN KNOWLEDGE

Our study showed that ADC at 3T DWI and SUV at 18F-FDG PET/CT had an inverse correlation in musculoskeletal tumours.