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Background: Cross-sectional imaging techniques as magnetic resonance enterography (MRE) may offer additional information on transmural inflammation, stricturing and fistulising complications in Crohn's disease (CD). The purpose of our study was to evaluate the diagnostic accuracy of Magnetic Resonance Imaging (MRI) combined with Diffusion-weighted Imaging (DWI) and MRE for determination of inflammation in small bowel CD., Methods: MR imaging examination was performed with a GE Signa EXCITE 3.0 T MRI scanner. The optimal b value in DWI with a learning cohort of patients was determined. The diagnostic accuracy for active lesions and disease activity were accessed by MRE combined with DWI., Results: The b value 800 s/mm(2) group showed the highest diagnostic sensitivity (74.19%) for diagnostic assessment of active Crohn's lesions on DWI. MRE combined with DWI showed the highest sensitivity (93.55%), specificity (89.47%) and diagnostic accuracy (92%) compared with MRE or DWI alone. The segmental MR score (MR-score-S) showed a significantly positive correlation with the Capsule Endoscopy Crohn's Disease Activity Index Score (CECDAI-S) (r = 0.717, p < 0.01). The total MR score (MR-score-T) showed significant association with C-reactive protein (CRP) (r = 0.445, p = 0.019) and erythrocyte sedimentation rate (ESR) (r = 0.688, p < 0.01)., Conclusions: MRE combined with DWI improves the diagnostic accuracy for active lesions and correlates the endoscopic disease activity. MRE with DWI could represent a non-invasive tool in assessing active inflammation in CD.

Objective: To measure surface skin dose from various cone-beam computed tomography (CBCT) scanners using point-dosimeters., Materials & Methods: A head anthropomorphic phantom was used with nanoDOT optically stimulated luminescence (OSL) dosimeters (Landauer Corp., Glenwood, IL) attached to various anatomic landmarks. The phantom was scanned using multiple exposure protocols for craniofacial evaluations in three different CBCT units and a conventional x-ray imaging system. The dosimeters were calibrated for each of the scan protocols on the different imaging systems. Peak skin dose and surface doses at the eye lens, thyroid, submandibular and parotid gland levels were measured., Results: The measured skin doses ranged from 0.09 to 4.62 mGy depending on dosimeter positions and imaging systems. The average surface doses to the lens locations were ~4.0 mGy, well below the threshold for cataractogenesis (500 mGy). The results changed accordingly with x-ray tube output (mAs and kV) and also were sensitive to scan field of view (SFOV). As compared to the conventional panoramic and cephalometric imaging system, doses from all three CBCT systems were at least an order of magnitude higher., Conclusions: Peak skin dose and surface doses at the eye lens, thyroid, and salivary gland levels measured from the CBCT imaging systems were lower than the thresholds to induce deterministic effects. However, our findings do not justify the routine use of CBCT imaging in orthodontics considering the lifetime-attributable risk to the individual.