Investigation of Bone Defects and Microcirculation With Computed Tomography and Magnetic Resonance Imaging

Overview

Subject of the proposed study is the non-invasive in vivo imaging of bone, bone marrow and localized microcirculation in test animals with osteoporosis, fractures and after placement of bone substitute material with volume computed tomography (VCT) (animals only) and functional magnetic resonance imaging (MRI). In vivo imaging by means of functional MRI and VCT is carried out in osteoporotic rats, both after the induction of fracture as well as after the placement of bone substitute material. Furthermore, patients with asymptomatic MM are investigated with functional MR-Imaging (Dynamic Contrast Enhancement- MRI and Intravoxel incoherent motion (IVIM)-imaging) longitudinally to predict the occurrence of osteolysis and the time to progression regarding SLIM-CRAB-Criteria (Rajkumar et al., Lancet Oncology, 2014). Hypothesis: 1. Affection of microcirculation at the junction of bone and bone substitute material can be displayed by VCT and functional MRI 2. Functional MRI has prognostic value regarding occurrence of osteolysis and progression to MM regarding SLIM-CRAB-Criteria

In an experimental study, rat models were used for imaging studies employing MRI (morphological, DCE- and DWI) and VCT. Mice were not used for imaging purposes due to the small size. Rats were shown to be of optimal size for small imaging studies. 144 patients with (suspected) asymptomatic MM were recruited for dynamic contrast-enhanced MRI (DCE-MRI) and diffusion weighted imaging (DWI) of the vertebral column as well as whole-body MRI using T1tse and STIR images every 6 months until progression and/ or occurrence of first osteolysis. While during planning and initiation of this prospective trial MM was defined by CRAB-criteria only, in 2014 the SLIM-CRAB-criteria were proposed by the International Myeloma Working Group (Rajkumar et al., Lancet Oncology, 2014) with the goal to treat patients before development of osteolysis or other CRAB-criteria. These criteria were consequently introduced in clinical practice at our institution during the observation period of this study, which affects both inclusion and progression criteria of this study. In order to obtain a conclusive cohort with homogenous inclusion and progression criteria, SLIM-CRAB-criteria where retrospectively applied to restage all patients regarding inclusion and progression to MM defined by SLIM-CRAB-criteria.