Multi-detector CT enterography in active inflammatory bowel disease: Image quality and diagnostic efficacy of a low-radiation high contrast protocol.

PURPOSE: To prospectively evaluate image quality and diagnostic efficacy of a low radiation-high contrast (LR-HC) CT Enterography (CTE) in active Inflammatory Bowel Disease (IBD). MATERIALS AND METHODS: Eighty-five (36M; 49F; 17-75 yrs) patients with active IBD underwent contrast-enhanced CTE and were stratified in two groups according to age (< or ≥45 yrs): Group A (N = 45; 32 ±â€¯9 yrs; 58 ±â€¯10 kg) and Group B (N = 40; 58 ±â€¯10 yrs; 61 ±â€¯13 kg). Each group received a different amount of radiation (Noise Index, NI) and non-ionic iodinated contrast media (LOCM) as follows: Group A (NI = 15; 2.5 ml/kg) and Group B (NI = 12.5; 2 ml/kg). Thyroid functional tests were performed in all patients of group A at 4-6 wks. Signal- and contrast-to-noise ratios were calculated for liver (L) and abdominal aorta (A). Statistical analysis was performed by Student's t- or Chi-square test for continuous and categorical data, respectively. RESULTS: No patient of Group A developed signs of thyrotoxicosis. SNRL, CNRL and diagnostic accuracy of CTE were 8.4 ±â€¯1.7 vs 8.9 ±â€¯2.1 (p = 0.256), 5.4 ±â€¯1.5 vs 5.6 ±â€¯1.7 (p = 0.486) and 91.1 vs 92.5% (p = 0.764) whereas the effective dose and the LOCM administered were 6.7 ±â€¯2.2 vs 13.9 ±â€¯6.0 mSv (p < 0.001) and 144 ±â€¯25 vs 122 ±â€¯25 ml (p < 0.001) for Group A and B, respectively. CONCLUSION: LR-HC CTE is a dose-effective protocol in the evaluation of active IBD in young patients.

High b-Value Diffusion MRI to Differentiate Recurrent Tumors from Posttreatment Changes in Head and Neck Squamous Cell Carcinoma: A Single Center Prospective Study.

Recently DW-MR Imaging has shown promising results in distinguishing between recurrent tumors and posttreatment changes in Head and Neck Squamous Cell Carcinoma (HNSSC). Aim of this study was to evaluate the diagnostic performances of DWI at high b-value (b = 2000 s/mm(2)) compared to standard b-value (b = 1000 s/mm(2)) and ADCratio values (ADCratio = ADC2000/ADC1000 × 100) to differentiate recurrent tumors from posttreatment changes after treatment of HSNCC. 20 patients (16 M, 4 F) underwent MR Imaging between 2 and 16 months (mean 7) after treatment. Besides morphological sequences, we performed single-shot echo-planar DWI at b = 1000 s/mm(2) and b = 2000 s/mm(2), and corresponding ADC maps were generated (ADC1000 and ADC2000, resp.). By considering contrast-enhanced T1-weighted images as references, ROIs were drawn in order to evaluate mean ADC1000, ADC2000, and ADCratio. The mean ADC1000 and ADC2000 in recurrent tumors were significantly lower than those in posttreatment changes (P = 0.001 and P = 0.016, resp.). Moreover, the mean ADCratio between the two groups showed a statistically significant difference (P = 0.002). Sensitivity, specificity, and accuracy of ADCratio were 82.0%, 100%, and 90%, respectively, by considering an optimal cutoff value of 65.5%. ADCratio is a promising value to differentiate between recurrent tumors and posttreatment changes in HNSCC and may be more useful than ADC1000 and ADC2000.