Regions Of Interest Curves Research Articles

Liquid Chromatography–High-Resolution Mass Spectrometry with ROI Strategy for Non-targeted Analysis of the In Vivo/In Vitro Ingredients Coming from Ligusticum chuanxiong hort

Mass spectral resolution for clean mass spectra is a very challenging task in non-targeted hyphenated techniques, especially for massive amounts of such data from herbs. In this work, the regions of interest (ROI) strategy was used to compress liquid chromatography–high-resolution mass spectrometry (LC–HRMS) data. For single or overlapped peaks, a rule of “first in, first out” was intended for visual recognition of features that could be of relevance in ROI curves. In the light of the two embedded peaks in a local segment, an improved selective ion analysis after ROI compression (ROI–SIA) possesses the main advantages of being rapid, automatic and parameter free. From the clean mass spectra above, we can estimate their correct feature sets that belong to the same compound. Tandem MS spectra were further determined, and peak annotations were rediscovered in known natural products by the interpretation of known MS/MS fragmentations. These procedures were tested in the analysis of the LC–HR–MS data coming from phytochemicals in Ligusticum chuanxiong with satisfactory results. The in vivo prototypes were also characterized in mice plasma after oral administration of the herbal extract. These analytical results provide an important basis for the identification of active ingredients, also used for a further investigation on the efficacy of different technologies.

Assessing liver function using dynamic Gd‐EOB‐DTPA‐enhanced MRI with a standard 5‐phase imaging protocol

To evaluate liver function obtained by tracer-kinetic modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data acquired with a routine gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced protocol. Data were acquired from 25 cases of nonchronic liver disease and 94 cases of cirrhosis. DCE-MRI was performed with a dose of 0.025 mmol/kg Gd-EOB-DTPA injected at 2 mL/sec. A 3D breath-hold sequence acquired 5 volumes of 72 slices each: precontrast, double arterial phase, portal phase, and 4-minute postcontrast. Regions of interest (ROIs) were selected semiautomatically in the aorta, portal vein, and whole liver on a middle slice. A constrained dual-inlet two-compartment uptake model was fitted to the ROI curves, producing three parameters: intracellular uptake rate (UR), extracellular volume (Ve), and arterial flow fraction (AFF). Median UR dropped from 4.46 10(-2) min(-1) in the noncirrhosis to 3.20 in Child-Pugh A (P = 0.001), and again to 1.92 in Child-Pugh B (P < 0.0001). Median Ve dropped from 6.64 mL 100 mL(-1) in the noncirrhosis to 5.80 in Child-Pugh A (P = 0.01). Other combinations of Ve and AFF changes were not significant for any group. UR obtained from tracer kinetic analysis of a routine DCE-MRI has the potential to become a novel index of liver function.

Relative renal uptake and transit time measurements using functional factor images and fuzzy regions of interest

The aim of the study was a quantitative comparison of relative renal uptake and both the whole-kidney and the parenchymal transit time derived from factor analysis of image sequences and provided by standard clinical procedues. In order to extract the stable, well-interpretable factors, factor analysis was performed locally in the problem-specific time and spatial windows and the resulting factor images either evaluated directly as functional images or used as fuzzy regions of interest (ROIs) for the subsequent extraction of time-activity curves from the analysed data. The values of relative renal uptake of the left kidney measured in the functional factor images, which demonstrate the initial accumulation of activity in renal parenchyma (mean 51.0%), did not differ significantly from the values obtained by a standard method (mean 51.5%, r = 0.98, P<0.001). Whole-kidney transit time calculated using fuzzy ROI curves correlated well with the reference values (r = 0.84, P<0.001); however, both its mean value (336.5 s) and the standard deviation (151.5 s) were substantially greater than those of the values provided by a standard procedure (262.8+/-86.9 s). Parenchymal transit time calculated using ROI curves correlated better with the transit time through a wider corticomedullary region rather than through a narrow cortical region, which is decisive in a differential diagnosis of renal disorders. In general, values of transit times provided by factor analysis correlated well with those provided by reference methods but with a shift towards the higher numerical values. This may have been a consequence of a greater extent of the automatically extracted fuzzy ROIs, or of occasionally delayed accumulation in the upper calyces. Results of the study provide quantitative evidence that the factor analysis of dynamic data, even without the introduction of prior physiological information, may yield clinically relevant information. However, some basic requirements, such as sufficiently high sampling frequency and count rate, adaption of the method to a specific clinical task, and proper selection of time and spatial windows for locally performed analysis, have to be fullfilled if the method is to be successfully applied clinically.

Identifying oesophageal contents using electrical impedance tomography

Investigations have been carried out using the Sheffield mark II real-time EIT system, to look at changes in conductivity associated with swallowing. A ring of 16 electrodes was placed around the neck of 10 subjects, who then performed swallows with four liquids of different conductivities, ranging from water ( sigma =0.03 mS cm-1) to salty soup ( sigma =35.8 mS cm-1). Results showed that the conductive and non-conductive liquids could be distinguished. Bolus transit times were calculated from region of interest curves, and the average transit time for the 10 subjects was found to be 320+or-100 ms.