Background & Aims Magnetic resonance elastography (MRE) is a non-invasive tool for staging liver fibrosis. We conducted a meta-analysis of individual participant data collected from published studies to assess the diagnostic accuracy of MRE and for staging liver fibrosis in patients with chronic liver diseases (CLD). Methods Through a systematic literature search of multiple databases (2003–2013), we identified studies on diagnostic performance of MRE for staging liver fibrosis in patients with CLD with native anatomy, using liver biopsy as the standard. We contacted study authors to collect data on each participant’s age, sex, body mass index (BMI), liver stiffness (measured by MRE), fibrosis stage, staging system used, degree of inflammation, etiology of CLD, and interval between MRE and biopsy. Through pooled analysis, we calculated the cluster-adjusted area under receiver-operating curve (AUROC), sensitivity, and specificity of MRE for any fibrosis (≥stage 1), significant fibrosis (≥stage 2), advanced fibrosis (≥stage 3), and cirrhosis (stage 4) Results We analyzed data from 12 retrospective studies, comprising 697 patients (mean age, 55±13 years; 59.4% male; mean BMI, 26.9±6.7 kg/m2; 92.1% with <1 year interval between MRE and biopsy; hepatitis C in 47.1%). Participants had fibrosis stages 0, 1, 2, 3, or 4 (19.5%, 19.4%, 15.5%, 15.9% and 29.7%, respectively). Mean AUROC values (and 95% confidence intervals) for diagnosis of any (≥stage 1), significant (≥stage 2), or advanced fibrosis (≥stage 3), and cirrhosis, were 0.84 (0.76–0.92), 0.88 (0.84–0.91), 0.93 (0.90–0.95), and 0.92 (0.90–0.94), respectively. Similar diagnostic performance was observed in stratified analysis based on sex, obesity, and etiology of CLD. The overall rate of failure of MRE was 4.3%. Conclusion Based on pooled analysis of data from individual participants, MRE has high accuracy for diagnosis of significant or advanced fibrosis and cirrhosis, independent of BMI and etiology of CLD. Prospective studies are warranted to better understand the diagnostic performance of MRE.

Objectives We conducted an individual participant data (IPD) pooled analysis on the diagnostic accuracy of magnetic resonance elastography (MRE) to detect fibrosis stage in patients with NAFLD. Methods Through a systematic literature search, we identified studies of MRE (at 60–62.5Hz) for staging fibrosis in patients with NAFLD, using liver biopsy as gold standard and contacted study authors for IPD. Through pooled analysis, we calculated the cluster-adjusted AUROC, sensitivity and specificity of MRE for any (≥stage 1), significant (≥stage 2) and advanced fibrosis (≥stage 3) and cirrhosis (stage 4). Results We included 9 studies reporting on 232 patients with NAFLD (mean age, 51±13y; 37.5% males; mean BMI, 33.5±6.7 kg/m2; interval between MRE and biopsy <1 year, 98.3%). Fibrosis stage distribution (stage 0/1/2/3/4) was 33.6%, 32.3%, 10.8%, 12.9% and 10.4%, respectively. Mean AUROC (and 95% confidence intervals) for diagnosis of any (≥stage 1), significant (≥stage 2) or advanced fibrosis (≥stage 3) and cirrhosis was 0.86 (0.82–0.90), 0.87 (0.82–0.93), 0.90 (0.84–0.94) and 0.91 (0.76–0.95), respectively. Similar diagnostic performance was observed in stratified analysis based on sex, obesity, and degree of inflammation. Conclusions Based on pooled IPD analysis, MRE has high diagnostic accuracy for detection of fibrosis in NAFLD, independent of BMI and degree of inflammation.

MRI more accurately predicts PCI preoperatively in patients undergoing evaluation for cytoreductive surgery.

In patients with Crohn disease, gadolinium-enhanced fat-suppressed spoiled GRE MR imaging better depicted the extent and severity of intestinal disease compared with single-shot fast SE imaging.

Adding DWI to routine MRI improves the sensitivity and specificity for depicting peritoneal metastases. Breath-hold DWI is now routinely used in all oncology patients referred for abdominal MRI at our institution.

Purpose: To evaluate the feasibility and added value of single breathhold diffusion-weighted (DW) imaging (DWI) in oncology patients undergoing abdominal MRI. Materials and Methods:A total of 169 patients with malignancy underwent abdominal MRI at 1.5T, including T1-weighted (T1W), T2-weighted (T2W), and dynamic gadolinium-enhanced imaging. Axial DWI was performed with a single-shot spin-echo (SE) echo-planar imaging (EPI) sequence using a b-value of 500 seconds/mm 2 . A total of 24 slices were obtained during a 20-second breathhold. Two observers reviewed the conventional MR images for tumor. Next, the DW images were reviewed for additional tumor not depicted on conventional MR images Results: For the 169 patients, additional tumors were noted on the DW images in 77 (0.46) for observer 1 and 67 (0.40) for observer 2. For observer 1 the additional tumor included lymphadenopathy (47), peritoneal metastases (15), renal (1), liver (12), and osseous (2), while for observer 2 the corresponding values were lymphadenopathy (40), peritoneal (12), renal (1), liver (6), osseous (4), and gastrointestinal (1). The DW images resolved as benign findings noted on the conventional MR images in three patients for observer 1 and four patients for observer 2. The conventional MR exam was entirely normal while the DW images showed tumor in 12 (0.07) patients for observer 1 and 10 (0.06) patients for observer 2.Conclusion: DWI is feasible in a single breathhold and provides additional clinically important information in oncology patients when added to routine abdominal MR sequences. DIFFUSION IS A PHYSICAL PROPERTY that describes the microscopic random movement of molecules in response to thermal energy. Also known as Brownian motion, diffusion may be affected by the biophysical properties of tissues such as cell organization and density, microstructure, and microcirculation. Diffusionweighted (DW) imaging (DWI) utilizes pulse sequences and techniques that are sensitive to very small-scale motion of water protons at the microscopic level. Singleshot echo-planar imaging (EPI) DWI is utilized to provide very rapid imaging sensitive to subtle small-scale alternations in diffusion. Areas of restricted water diffusion are displayed as areas of high signal intensity (1-4).The application of DWI for the evaluation of acute cerebral infarcts is well established. However, the challenges posed by DWI of the abdomen and pelvis have limited its application for body MRI. On DWI, artifacts related to physiologic motion, susceptibility, and chemical shift are compounded by inherent limitations in signal-to-noise ratio and image resolution. The larger fields of view used for abdominal imaging accentuate many of the artifacts inherent in DWI and single-shot EPI (1-4).Hardware and technical advances in MRI have overcome many of these limitations, making DWI feasible for abdominal and pelvic MRI. Recent works have described the use of single-shot EPI DWI for evaluation of lymphadenopathy (5), liver tumors (6 -8), renal masses (9 -15), prostate cancer ...

Double-contrast MR imaging demonstrated more peritoneal tumors than CT or unenhanced spin-echo MR imaging.

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