Supplemental value of diffusion‐weighted whole‐body imaging with background body signal suppression (<scp>DWIBS</scp>) technique to whole‐body magnetic resonance imaging in detection of bone metastases from thyroid cancer

<jats:title>Abstract</jats:title><jats:sec><jats:title>Introduction</jats:title><jats:p>We compared the efficacy of whole‐body <jats:styled-content style="fixed-case">MRI</jats:styled-content> (<jats:styled-content style="fixed-case">WBMRI</jats:styled-content>) with and without diffusion‐weighted whole‐body imaging with background body signal suppression (<jats:styled-content style="fixed-case">DWIBS</jats:styled-content>) using a 3.0‐<jats:styled-content style="fixed-case">T MR</jats:styled-content> scanner to [18<jats:styled-content style="fixed-case">F</jats:styled-content>] fluoro‐2‐<jats:styled-content style="fixed-case">D</jats:styled-content>‐glucose positron emission tomography with <jats:styled-content style="fixed-case">CT</jats:styled-content> (integrated <jats:styled-content style="fixed-case">FDG‐PET</jats:styled-content>/<jats:styled-content style="fixed-case">CT</jats:styled-content>) for the detection of bone metastases in patients with differentiated thyroid carcinoma (<jats:styled-content style="fixed-case">DTC</jats:styled-content>).</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We examined 23 patients (16 women, 7 men; mean age, 56; range 17–74) with <jats:styled-content style="fixed-case">DTC</jats:styled-content> who had undergone total thyroidectomy and were hospitalised to receive [<jats:styled-content style="fixed-case">I</jats:styled-content>‐131<jats:styled-content style="fixed-case">I</jats:styled-content>] therapy. All patients underwent both <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> with <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> and whole‐body <jats:styled-content style="fixed-case">FDG‐PET</jats:styled-content>/<jats:styled-content style="fixed-case">CT</jats:styled-content>. The skeletal system was classified into 13 anatomic segments and assessed for the presence of bone metastases. Bone metastases were verified when positive findings were indicated on at least two imaging modalities: post‐treated [131<jats:styled-content style="fixed-case">I</jats:styled-content>] whole‐body scans, <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> without <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> (<jats:styled-content style="fixed-case">T</jats:styled-content>1‐weighted images and short‐inversion time inversion recovery images), [18<jats:styled-content style="fixed-case">F</jats:styled-content>]‐<jats:styled-content style="fixed-case">FDG‐PET</jats:styled-content> and <jats:styled-content style="fixed-case">CT</jats:styled-content>.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Bone metastases were confirmed in 78/290 (27%) segments in 20 (87%) of 23 patients. The sensitivities for bone metastases on a segment basis using <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> with <jats:styled-content style="fixed-case">DWIBS</jats:styled-content>, <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> without <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> and integrated <jats:styled-content style="fixed-case">FDG‐PET</jats:styled-content>/<jats:styled-content style="fixed-case">CT</jats:styled-content> were 64 of 78 (82%), 50 of 78 (64%) and 62 of 78 (79%), respectively; the difference between values of <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> with and without <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> was statistically significant (<jats:italic>P</jats:italic> = 0.0015). The overall accuracies of <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> with <jats:styled-content style="fixed-case">DWIBS</jats:styled-content>, <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> without <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> and integrated <jats:styled-content style="fixed-case">FDG‐PET</jats:styled-content>/<jats:styled-content style="fixed-case">CT</jats:styled-content> were 273 of 290 (94%), 261 of 290 (90%) and 272 of 290 (94%), respectively; the difference between values of <jats:styled-content style="fixed-case">MRI</jats:styled-content> with and without <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> was also statistically significant (<jats:italic>P</jats:italic> = 0.003). There were only one to three false positive segments and the difference among specificities was not statistically significant in these modalities.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Adding <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> improved the sensitivity and the overall accuracy of <jats:styled-content style="fixed-case">WBMRI</jats:styled-content> using 3.0‐<jats:styled-content style="fixed-case">T MRI</jats:styled-content> for the detection of bone metastases in patients with <jats:styled-content style="fixed-case">DTC</jats:styled-content>. There was no statistically significant difference in diagnostic accuracy between <jats:styled-content style="fixed-case">MRI</jats:styled-content> with <jats:styled-content style="fixed-case">DWIBS</jats:styled-content> and integrated <jats:styled-content style="fixed-case">FDG‐PET</jats:styled-content>/<jats:styled-content style="fixed-case">CT</jats:styled-content>.</jats:p></jats:sec>