44 results about "Arterial input function" patented technology

The invention provides a method, an image analysis software product, and a system for medical imaging analysis for estimating contrast agent extravasation in contrast agent based perfusion imaging such as MRI dynamic contrast enhanced (DCE) imaging, and in particular correction, compensation, or visualization of extravascular leakage of contrast agent in tumors. According to the invention, the effect of extravasation is directly manifested in the tail part of an observed, apparent residue function, R′(t), obtained directly by de-convoluting the expression C(t)=R′(t)Cp′(t) with the arterial input function (AIF). A leakage rate or extravasation constant is determined directly from the tail part of the determined apparent residue function. The invention also relates to distinguishing between T1-dominant and T2*-dominant extravasation effects in perfusion imaging to from the sign of the tail part of the determined apparent residue function and to an automated method for DSC-MRI involving correction for contrast agent extravasation and partial volume effects.

A graphical user interface and method allows a user to interactively select an arterial input function. An anatomical image and time-course data corresponding to a selected region of interest are displayed simultaneously. The time-course data is displayed as an array of graphs, annotated with best-fit curves and parameters derived from fitting the time-course data. The region displayed in the graphs may be updated by panning and zooming with a mouse in the image. Time-course data corresponding to a graph is selected for use in deriving an arterial input function. The arterial input function is used to calculate maps of hemodynamic parameters.

Prior approaches have delivered 17O2 to a subject by inhalation, but the relationship between local signal changes and metabolism has been complicated by H217O created in non-cerebral tissues. During a brief pulse of 17O2 inhalation, this arterial input function for H217O is negligible due to convective transport delays. Additional delays in the arterial input function due to restricted diffusion of water makes pulsed inhalation of 17O2 even more effective. Accordingly, ventilator system are provided to deliver 17O2 as a brief pulse to a subject. Subsequent MR imaging demonstrates delayed appearance of H217O in the cerebral ventricles, suggesting that the arterial input function of H217O is delayed by restricted water diffusion in addition to convective transit delays. Delivery as a brief pulse therefore offers significant advantages in relating MR signal changes directly to metabolism.

The invention relates to elements of a method (1) for determining a damage characteristic value of a kidney (2). Images comprising the kidney (2) and the kidney artery (3) are entered into the method (1), from a three-dimensional digital subtraction angiography which is carried out by administering a contrast medium at the proximal end of the kidney artery (3) and comprises a fill run and a mask run, said method (1) comprising the following method steps: S1) determining a parenchymal blood volume into which the subtractions from images of the fill run and the mask run of the three-dimensional digital subtraction angiography are entered, additionally determining an arterial input function and normalising the parenchymal blood volume with said arterial input function; S2) segmenting the kidney (2), determining an average normalised parenchymal blood volume value, and determining a total value of the parenchymal blood volume into which the normalised parenchymal blood volume values of the segmentation of the kidney (2) are entered; S3) receiving an average normalised parenchymal blood volume normal value and a total normal value for a parenchymal blood volume, and determining at least one damage characteristic value of the kidney (2) into which the average normalised parenchymal blood volume value and the average normalised parenchymal blood volume normal value and / or the total value of the parenchymal blood volume and the total normal value of a parenchymal blood volume are entered; S4) issuing the at least one damage characteristic value of the kidney (2).

The invention provides a magnetic resonance perfusion imaging postprocessing method and a system thereof. The method comprises the following steps of perfusing image filtering to an original brain, removing a brain edge and acquiring a filtered brain perfusion image; receiving an area selection instruction of a user, acquiring a selected area of a middle artery area in the filtered brain perfusion image and outputting a weighted artery input curve assessing an artery input function; according to an improved Gamma function, fitting the weighted artery input curve and a concentration time curve respectively so as to obtain the optimized artery input curve and the concentration time curve; according to an improved singular matrix decomposition method based on a non-parametric model, solving a relative quantification parameter of perfusion. Through carrying out weighted optimization on AIF and a solving matrix, sensitivity to a noise is reduced; a simplified and effective Gamma function is used to carry out fitting, a non-linear problem is converted into linear solution, and a post-treatment speed is accelerated.

A method of generating an enhanced perfusion image comprising the use of a blind deconvolution algorithm and the adiabatic approximation to the Johnson and Wilson model (aaJW) and generation of an image, wherein the blind deconvolution algorithm and the aaJW model are used in the generation of values of the following parameters: voxel specific arterial input function cp[t] and voxel specific tissue residue function r[t].

A method for pharmacokinetic analysis, including: receiving time-series medical image data of a patient introduced with a contrast agent; identifying a reference region in the medical image data; identifying a plurality of points of interest in the medical image data; measuring an intensity of voxels in the reference region; and for each point of interest, measure an intensity of voxels therein, use the measured reference region and point of interest intensities to obtain an expression relating the point of interest's voxel concentration to that of the reference region, wherein the expression is a five-parameter nonlinear model with no reference to an arterial input function; and obtain values for each of the five-parameters by solving the expression and use the obtained values to determine whether the point of interest is malignant.