NCT02299856.

No abstract

Purpose To evaluate MRI T1 and T2 mapping with calculation of extracellular volume (ECV) for diagnosis and grading of liver fibrosis. Materials and Methods Different grades of fibrosis were induced in 60 male Sprague-Dawley rats by bile duct ligation (BDL) and carbon-tetrachloride (CCl) intoxication. Portal pressure was measured invasively, whereas hepatic fibrosis was quantified by hydroxyproline content, Sirius red staining, and α smooth muscle actin staining. T1 values, T2 values, and ECV were assessed by using quantitative MRI mapping techniques. Results T1 values in animals 4 weeks after BDL were greater than in control animals (718 msec ± 74 vs 578 msec ± 33, respectively; P < .001). T2 values at 4 weeks were also greater in animals that underwent BDL than in control animals (46 msec ± 6 vs 29 msec ± 2, respectively; P < .001). Similar T1 and T2 findings were observed after CCl intoxication. ECV was greater in animals 4 weeks after BDL compared with control animals (31.3% ± 1.3 vs 18.2% ± 3.5, respectively; P < .001), with similar results after CCl intoxication. High correlations were found between ECV and hepatic hydroxyproline content (BDL: r = 0.68, P < .001; CCl: r = 0.65, P < .001), Sirius red staining (BDL: r = 0.88, P < .001; CCl: r = 0.82, P < .001), α smooth muscle actin staining (BDL: r = 0.70, P < .001; CCl: r = 0.73, P < .001), and portal pressure (BDL: r = 0.54, P = .003; CCl: r = 0.39, P = .043). Conclusion Elevation of T1 and T2 values and ECV was associated with severity of liver fibrosis and portal hypertension in an experimental animal model.

BackgroundCardiac magnetic resonance (CMR) can detect inflammatory myocardial alterations in patients suspected of having acute myocarditis. There is limited information regarding the degree of normalization of CMR parameters during the course of the disease and the time window during which quantitative CMR should be most reasonably implemented for diagnostic work‐up.Methods and ResultsTwenty‐four patients with suspected acute myocarditis and 45 control subjects underwent CMR. Initial CMR was performed 2.6±1.9 days after admission. Myocarditis patients underwent CMR follow‐up after 2.4±0.6, 5.5±1.3, and 16.2±9.9 weeks. The CMR protocol included assessment of standard Lake Louise criteria, T1 relaxation times, extracellular volume fraction, and T2 relaxation times. Group differences between myocarditis patients and control subjects were highest in the acute stage of the disease (P<0.001 for all parameters). There was a significant and consistent decrease in all inflammatory CMR parameters over the course of the disease (P<0.01 for all parameters). Myocardial T1 and T2 relaxation times—indicative of myocardial edema—were the only single parameters showing significant differences between myocarditis patients and control subjects on 5.5±1.3‐week follow‐up (T1: 986.5±44.4 ms versus 965.1±28.1 ms, P=0.022; T2: 55.5±3.2 ms versus 52.6±2.6 ms; P=0.001).ConclusionsIn patients with acute myocarditis, CMR markers of myocardial inflammation demonstrated a rapid and continuous decrease over several follow‐up examinations. CMR diagnosis of myocarditis should therefore be attempted at an early stage of the disease. Myocardial T1 and T2 relaxation times were the only parameters of active inflammation/edema that could discriminate between myocarditis patients and control subjects even at a convalescent stage of the disease.

computed tomography (ct) and magnetic resonance imaging (MRi) can quantify muscle mass and quality. However, it is still unclear if ct and MRi derived measurements can be used interchangeable. In this prospective study, fifty consecutive participants of a cancer screening program underwent same day low-dose chest ct and MRi. cross-sectional areas (cSA) of the paraspinal skeletal muscles were obtained. CT and MRI muscle fat infiltration (MFI) were assessed by mean radiodensity in Hounsfield units (HU) and proton density fat fraction (MRi pDff), respectively. cSA and Mfi were highly correlated between CT and MRI (CSA: r = 0.93, P < 0.001; MFI: r = − 0.90, P < 0.001). Mean CSA was higher in CT compared to MRI (46.6cm 2 versus 43.0cm 2 ; P = 0.05) without significance. Based on MRI pDff , a linear regression model was established to directly estimate skeletal muscle fat content from ct. Bland-Altman plots showed a difference between measurements of − 0.5 cm 2 to 7.6 cm 2 and − 4.2% to 2.4% regarding measurements of cSA and Mfi, respectively. in conclusion, the provided results indicate interchangeability of ct and MRi derived imaging biomarkers of skeletal muscle quantity and quality. comparable to MRi pDff , skeletal muscle fat content can be quantified from CT, which might have an impact of analyses in larger cohort studies, particularly in sarcopenia patients. Decrease in skeletal muscle quantity and quality, commonly termed sarcopenia, is known as a strong risk factor for adverse outcomes in several chronic and malignant diseases. Sarcopenia was shown to have high socioeconomic and personal burden and leads to impaired activity in daily life, decreased mobility, loss of independency and a higher mortality 1-3. Initially, sarcopenia was considered to be an age-related phenomenon 4. However, it is now increasingly realized that sarcopenia may also occur in younger patients, for example secondary due to systemic diseases. Moreover, it was realized that sarcopenia may not be captured by conventional anthropometric measurements such as body mass index (BMI) or waist-to-hip-ratio, particularly in obese patients 1,5. Amount and quality of skeletal muscles can be assessed by cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Previous studies indicate that both modalities may provide imaging based quantitative biomarkers of sarcopenia, and that these biomarkers may reveal prognostic information in various severe diseases 6-10. Thereby, cross sectional areas (CSA) of skeletal muscles at distinct anatomical landmarks were shown to provide accurate surrogates of total skeletal muscle amount and therefore may be used to identify patients with low muscle mass 1,6,7. The most common approaches to estimate skeletal muscle amount are determination of circumferential skeletal muscle area or psoas muscle area, both typically obtained at lumbar vertebral levels 1. However, these landmarks are frequently not captured in several imaging protocols, although sarcopenia is known to b...