A novel use of diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression to diagnose infectious aortitis

BackgroundDiffusion-weighted whole-body imaging with background body signal suppression is one of the whole-body magnetic resonance imaging techniques and is effective in diagnosing inflammatory and infectious diseases. We aimed to evaluate the diagnostic performance of this modality in infectious aortitis, which remains unclear. MethodsThe study participants were 32 patients with suspected infectious aortitis who underwent computed tomography and magnetic resonance imaging between September 2020 and November 2022. Sensitivity, specificity, and areas under the curve of each imaging modality were studied using a diagnosis based on a combination of imaging results, clinical symptoms, and laboratory tests. Decision curve analysis was performed to determine the benefit of adding magnetic resonance imaging to computed tomography. ResultsThe median age was 74 years, and 23 participants were men. Fifteen patients (47%) were diagnosed with infectious aortitis. Positive findings for infectious aortitis were identified in 19, 18, and 14 patients by computed tomography, diffusion-weighted whole-body imaging, and the combination of both modalities, respectively. Sensitivity, specificity, and area under the curve for correct diagnosis were 93.3%, 70.6%, and 0.82 (95% confidence interval 0.69-0.95), respectively for computed tomography, 93.3%, 76.5%, and 0.85% (95% confidence interval 0.73%-0.97), respectively for diffusion-weighted imaging, and 86.7%, 94.1%, and 0.90 (95% confidence interval 0.80-0.10), respectively for the combination of both modalities. Decision curve analysis reinforced the clinical benefit of combining the two imaging modalities across all ranges of the probability thresholds. ConclusionsDiffusion-weighted whole-body imaging with background body signal suppression is an effective diagnostic tool for infectious aortitis, especially when combined with computed tomography. Clinical PerspectiveInfectious aortitis is a serious disease that is difficult to accurately diagnose. Although PET-CT is associated with high diagnostic performance, limited access to this modality has encouraged the development of an alternative modality. The whole-body MRI with DWIBS is a more available modality, which is commonly used for cancer diagnosis but is also considered effective in diagnosing infectious diseases. The combination of DWIBS and non-contrast CT yielded a sensitivity of 86.7% (95% CI: 59.5-98.3%), a specificity of 94.1% (95% CI: 71.3-99.9%), and an AUC of 0.90 (95% CI: 0.80-0.10) for the diagnosis of infectious aortitis. DWIBS can be a useful modality as an alternative to PET-CT.