ABSTRACT
AIM: To evaluate the role of diffusion-weighted MRI (DW-MRI) in detecting and differentiating acute from chronic bowel inflammation in patients with Crohn's disease (CD). MATERIALS AND METHODS: MR-enteroclysis examinations with DW-MRI were reviewed from 24 patients with histologically proven CD. Segments of bowel were evaluated for acute and chronic inflammation in three different reviews of the MRI images: T2w alone, T2w + DWI, and T2w + CET1w. Mean ADC values of normal bowel segments, as well as bowel segments with acute and chronic inflammation were calculated and compared. Analyses of receiver-operating characteristic (ROC) curve were performed. RESULTS: Hundred and forty four bowel segments in total were reviewed. Inflammation was present in 45 segments. Acute inflammation was present in 31 segments, chronic inflammation in 14. 98 bowel segments showed no inflammatory activity. Sensitivity and specificity for differentiation between normal and inflamed bowel segments was 0.6, 0.67, and 0.80 on T2w, T2w + DWI, and T2w + CET1w datasets, respectively. Specificities for differentiation between normal and inflamed bowel segments were 0.96, 0.96, and 0.98. Sensitivities for differentiation between acute and chronically inflamed bowel segments were 0.85, 0.91, and 0.96, and specificities were 0.88, 0.89, and 1.0, respectively. The mean ADC value of normal bowel (2.18 ± 0.37 × 10(-3) mm(2)/s) was statistically significantly greater than the mean value of inflamed bowel segments (p < 0.001). The mean ADC value of acutely inflamed bowel segments was statistically significantly lower than that of chronically inflamed bowel segments (1.09 ± 0.18 × 10(-3) vs. 1.55 ± 0.21 × 10(-3) mm(2)/s) (p < 0.001). Estimated area under the ROC curve for the diagnosis of acute vs. chronic inflammation was 0.950. A threshold of ADC value of 1.41 × 10(-3) mm(2)/s was optimal for calculation of sensitivity and specificity. CONCLUSION: DW-MRI improves detection and differentiation of acute vs. chronic inflammatory changes of the bowel in patients with CD compared to T2w-images alone.
Subject(s)
Diffusion Magnetic Resonance Imaging/methods , Inflammatory Bowel Diseases/diagnostic imaging , Acute Disease , Adult , Chronic Disease , Diagnosis, Differential , Female , Humans , Male , Retrospective Studies , Sensitivity and SpecificityABSTRACT
PURPOSE: The aim of the study was to evaluate contrast-enhanced MRI, diffusion-weighted MRI (DW MRI), and (68)Ga-DOTATATE positron emission tomography (PET)/CT in the detection of intermediate to well-differentiated neuroendocrine tumors (NET) of the pancreas. METHODS: Eighteen patients with pathologically proven pancreatic NET who underwent MRI including DW MRI and PET/CT within 6 weeks of each other were included in this retrospective study. Two radiologists evaluated T2-weighted (T2w), T2w + DW MRI, T2w + contrast-enhanced T1-weighted (CE T1w) MR images, and PET/CT for NET detection. The sensitivity and level of diagnostic confidence were compared among modalities using McNemar's test and a Wilcoxon signed rank test. Apparent diffusion coefficients (ADC) of pancreatic NETs and normal pancreatic tissue were compared with Student's t test. RESULTS: Of the NETs, 8/23 (34.8 %) and 9/23 (39.1 %) were detected on T2w images by observers 1 and 2, respectively. Detection rates improved significantly by combining T2w images with DW MRI (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05) or CE T1w images (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05). Detection rates of pancreatic NET with PET/CT (both observers: 23/23 = 100 %) were statistically significantly higher than with MRI (p < 0.05). The mean ADC value of NET (1.02 ± 0.26 × 10(-3) mm(2)/s) was statistically significantly lower than that of normal pancreatic tissue (1.48 ± 0.39 × 10(-3) mm(2)/s). CONCLUSION: DW MRI is a valuable adjunct to T2w imaging and comparable to CE T1w imaging in pancreatic NET detection, quantitatively differentiating between NET and normal pancreatic tissue with ADC measurements. (68)Ga-DOTATATE PET/CT is more sensitive than MRI in the detection of pancreatic NET.
