Magnetic Resonance Enterography in the Diagnosis of Crohn’s Disease Using Diffusion-Weighted Imaging with Background Body Signal Suppression (DWIBS) Sequence:

The Doctoral Thesis “Magnetic resonance enterography in diagnosis of Crohn’s disease using diffusion-weighted imaging with background body signal suppression (DWIBS) sequence” deals with diagnosis of terminal ileitis and evaluation of activity using the DWIBS sequence. The aim of the Thesis is to evaluate possible advantages of DWIBS sequences in diagnosis of Crohn’s Disease (CD), without prior preparation of the bowel and evaluation of the activity of CD localised in the terminal ileum. The Thesis includes data gathered from 106 adult patients without any clinical, laboratory-based or radiological evidence of the inflammatory bowel disease, as well as 5 adult patients and 12 children with proven CD localised in the terminal ileum. The dissertation analyses the hitherto insufficiently studied aspects of diffusion-weighted imaging (DWI) (quantitative evaluation of diffusion restriction in bowel walls of patients without prior preparation of small and large intestines), as well as the application of quantitative evaluation of diffusion restriction in CD using apparent diffusion coefficients (ADC). The scope of the research was to estimate potential advantages and benefits of the DWIBS sequence using the non-selective fat suppression technique STIR (inversion recovery with a short T1 time) over the conventional DWI sequence with the spectrally selective fat suppression technique SPIR (spectral pre-saturation with inversion recovery). The study found that the performance of the DWIBS sequence statistically significantly lags behind the conventional DWI sequence with the spectrally selective SPIR fat signal suppression technique. The results showed that despite improved resolution and qualitatively better representation of inflamed areas, the DWIBS sequence is not reliable for both quantitative diagnosis of CD without prior preparation of the patient and evaluation of disease activity using ADC measurements. Within the framework of the research, recommendations have been developed on the choice of fat suppression technique for DWI sequences for evaluating activity of Crohn’s disease, located in the terminal ileum, as well as on the suitability of ADC measurements for quantitative diagnosis of CD by MRE without prior preparation of the patient’s intestinal tract.