MR elastography of human lung parenchyma: technical development, theoretical modeling and in vivo validation

Purpose:

To develop a novel MR‐based method for visualizing the elastic properties of human lung parenchyma in vivo and to evaluate the ability of this method to resolve differences in parenchymal stiffness at different respiration states in healthy volunteers.

Materials and Methods:

A spin‐echo MR Elastography (MRE) pulse sequence was developed to provide both high shear wave motion sensitivity and short TE for improved visualization of lung parenchyma. The improved motion sensitivity of this approach was modeled and tested with phantom experiments. In vivo testing was then performed on 10 healthy volunteers at the respiratory states of residual volume (RV) and total lung capacity (TLC).

Results:

Shear wave propagation was visualized within the lungs of all volunteers and was processed to provide parenchymal shear stiffness maps for all 10 subjects. Density corrected stiffness values at TLC (1.83 ± 0.22 kPa) were higher than those at the RV (1.14 ± 0.14 kPa) with the difference being statistically significant (P < 0.0001).

Conclusion:

¹H‐based MR elastography can noninvasively measure the shear stiffness of human lung parenchyma in vivo and can quantitate the change in shear stiffness due to respiration. The values obtained were consistent with previously reported in vitro assessments of cadaver lungs. Further work is required to increase the flexibility of the current acquisition and to investigate the clinical potential of lung MRE. J. Magn. Reson. Imaging 2011;33:1351–1361. © 2011 Wiley‐Liss, Inc.     

Locoregional treatments for hepatocellular carcinoma: Current evidence and future directions

Liver cancers are the second most frequent cause of global cancer-related mortality of which 90% are attributable to hepatocellular carcinoma(HCC).Despite the advent of screening programmes for patients with known risk factors,a substantial number of patients are ineligible for curative surgery at presentation with limited outcomes achievable with systemic chemotherapy/external radiotherapy. This has led to the advent of numerous minimally invasive options including but not limited to trans-arterial chemoembolization,radiofrequency/microwave ablation and more recently selective internal radiation therapy many of which are often the first-line treatment for select stages of HCC or serve as a conduit to liver transplant. The authors aim to provide a comprehensive overview of these various image guided minimally invasive therapies with a brief focus on the technical aspects accompanied by a critical analysis of the literature to assess the most up-to-date evidence from comparative systematic reviews and meta-analyses finishing with an assessment of novel combination regimens and future directions of travel.     

Structure-function relationships of citrus limonoids on p38 MAP kinase activity in human aortic smooth muscle cells

Limonoids, abundantly present in citrus fruits, have potential role in reducing risk of different type of cancer. In the present study, we hypothesized that seven structurally different limonoids would involve in inflammatory pathway via modulating p38 MAP kinase activity at various extent in vascular smooth muscle cells. Results demonstrated that the different functional groups containing limonoids had differential effects on the p38 MAP kinase activity in human aortic smooth muscle cells. Among seven limonoids, nomilin exhibited the highest (38%) inhibition of p38 MAP kinase activity, followed by limonin (19%), deacetyl nomilin (19%), and defuran nomilin (17%). While defuran limonin and methyl nomilinate showed no significant decrease in p38 MAP kinase activity, obacunone significantly increased the p38 MAP kinase activity by 38%. Furthermore, TNF-α induced p38 MAP kinase activity in the smooth muscle cells was completely inhibited by nomilin. Thus our data provide the first evidence that nomilin is the potent natural inhibitor for p38 MAP kinase activity in human aortic smooth muscle cells. These data also suggest that a seven-membered A ring with acetoxy group, present in nomilin, seems to be essential for its inhibitory activity on p38 MAP kinase.     

Dissipation Kinetics of Chlorantraniliprole in Soils of Sugarcane Ecosystem

Dissipation kinetics of chlorantraniliprole was studied in sandy loam soils of sugarcane ecosystem by adopting a rapid analytical method. The recovery of chlorantraniliprole was 91.67 % when extracted with ethyl acetate as against only 65.58 % in acetonitrile-based extraction. An additional cleanup step with primary secondary amine did not enhance the recovery significantly over the no-cleanup method. The ethyl acetate-based extraction followed by direct quantification in HPLC (High-performance liquid chromatography) without any cleanup facilitated rapid quantification of chlorantraniliprole residues. The LOQ (limit of quantification) of the method was 0.01 μg/g. The half-life of chlorantraniliprole was 6.50 and 6.81 days for the recommended and double the recommended doses, respectively.     

Lymphatic Filariasis: Perspectives on Lymphatic Remodeling and Contractile Dysfunction in Filarial Disease Pathogenesis

Lymphatic filariasis, one of the most debilitating diseases associated with the lymphatic system, affects over a hundred million people worldwide and manifests itself in a variety of severe clinical pathologies. The filarial parasites specifically target the lymphatics and impair lymph flow, which is critical for the normal functions of the lymphatic system in maintenance of body fluid balance and physiological interstitial fluid transport. The resultant contractile dysfunction of the lymphatics causes fluid accumulation and lymphedema, one of the major pathologies associated with filarial infection. In this review, we take a closer look at the contractile mechanisms of the lymphatics, its altered functions, and remodeling during an inflammatory state and how it relates to the severe pathogenesis underlying a filarial infection. We further elaborate on the complex host–parasite interactions, and molecular mechanisms contributing to the disease pathogenesis. The overall emphasis is on elucidating some of the emerging concepts and new directions that aim to harness the process of lymphangiogenesis or enhance contractility in a dysfunctional lymphatics, thereby restoring the fluid imbalance and mitigating the pathological conditions of lymphatic filariasis.     

Highly accelerated cardiac MRI using iterative SENSE reconstruction: initial clinical experience

To evaluate the qualitative and quantitative performance of an accelerated cardiovascular MRI (CMR) protocol that features iterative SENSE reconstruction and spatio-temporal L₁-regularization (IS SENSE). Twenty consecutively recruited patients and 9 healthy volunteers were included. 2D steady state free precession cine images including 3-chamber, 4-chamber, and short axis slices were acquired using standard parallel imaging (GRAPPA, acceleration factor = 2), spatio-temporal undersampled TSENSE (acceleration factor = 4), and IS SENSE techniques (acceleration factor = 4). Acquisition times, quantitative cardiac functional parameters, wall motion abnormalities (WMA), and qualitative performance (scale: 1-poor to 5-excellent for overall image quality, noise, and artifact) were compared. Breath-hold times for IS SENSE (3.0 ± 0.6 s) and TSENSE (3.3 ± 0.6) were both reduced relative to GRAPPA (8.4 ± 1.7 s, p < 0.001). No difference in quantitative cardiac function was present between the three techniques (p = 0.89 for ejection fraction). GRAPPA and IS SENSE had similar image quality (4.7 ± 0.4 vs. 4.5 ± 0.6, p = 0.09) while, both techniques were superior to TSENSE (quality: 4.1 ± 0.7, p < 0.001). GRAPPA WMA agreement with IS SENSE was good (κ > 0.60, p < 0.001), while agreement with TSENSE was poor (κ < 0.40, p < 0.001). IS SENSE is a viable clinical CMR acceleration approach to reduce acquisition times while maintaining satisfactory qualitative and quantitative performance.