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R A Karwoski

Publications and source records attributed to R A Karwoski.

6 recordsLinked to original sources
PubMed2003

A quick, reliable, and automated method for fat cell sizing.

Mean diameters of fat cells from abdominal tissues from 31 volunteers were determined by three methods based on fat cell isolation after collagenase digestion and methylene blue staining. The three methods were direct microscopy (Micro), manual measurement of diameters from digital images by using the public domain NIH Image program (Scion), and automated measurement of diameters from digital images using a customized program developed by Biomedical Imaging Resource at Mayo Clinic (AdCount). There was excellent agreement between the methods' measurement of mean abdominal fat cell diameter (concordance correlation coefficient >0.84). The Scion method gave slightly but systematically lower mean abdominal fat cell diameters than did either AdCount or Micro. The AdCount approach produced results that are comparable to those from Micro. Comparison of AdCount and Micro in measuring diameters of fat cells from thigh confirmed the good comparability between the two methods independent of fat depot. AdCount is very reliable, and the quickest and most objective of the three methods in measuring fat cell diameters from various depots.

Adipocytes↗
PubMed1997

Analysis of cardiac function by MRI and stereology.

Design-based stereology and phase contrast magnetic resonance imaging (MRI) were combined to monitor changes in the volume of the four chambers of the human heart during the cardiac cycle. The data set consisted of 18 adjacent slices (or 'scanning levels') of 0.5 cm thickness, perpendicular to the long axis of the body, and encompassing the whole heart of a healthy volunteer. At each scanning level, a cardiac gated MR image was obtained at each of 16 equally spaced time frames within the cardiac cycle. Given stationarity with respect to time, absence of image artefacts and appropriate definition of chamber boundaries, for each time frame unbiased estimates of total blood volume in the relevant heart chambers were efficiently obtained using the Cavalieri method and point counting. Combined with a proper MRI acquisition, modern stereological methods constitute an efficient and reliable tool to quantify cardiac function noninvasively.

Blood Volume↗
PubMed1990

EEG scalp electrode projection onto three-dimensional surface rendered images of the brain.

A technique is described for generating magnetic resonance-based, surface rendered images of the brain with electroencephalographic (EEG) scalp electrode positions projected onto the cortical surface. This technique (EEG electrode projection) was used in 10 patients who subsequently underwent surgery for medically intractable frontal lobe epilepsy. In most cases of intractable epilepsy, successful surgery entails the resection of electrophysiologically abnormal cortical tissue rather than an identifiable mass lesion. EEG electrode projection is a unique and useful surgical tool because it provides images that spatially correlate the surface anatomy of the brain and the electrophysiologic abnormality recorded at the scalp. Excellent correlation was found between cortical topography delineated by the surface rendered images and cortical anatomy at surgery. Agreement between EEG electrode projection and electrocorticography as to the location of the electrophysiologic abnormality increases confidence that appropriate cortical areas have been identified for resection. The technique provides new and unique insight into important anatomic-electrophysiologic relationships and aids in formulation of surgical strategy.

Adult↗
PubMed1988

Estimation of tissue volume from serial tomographic sections. A statistical random marking method.

Computer operator-interactive planimetric methods that have been employed to measure volume of a selected tissue in serial computed tomographic sections are time consuming, and the accuracy of the measurement is limited by the operator's skill in outlining the tissue. We introduce an alternate method that is 5 to 6 times faster than planimetry and is independent of the operator's outlining dexterity. This method involves the random marking of voxels in a three-dimensional array of known size and subsequent identification of the proportion of those voxels that are within the tissue of interest. Tissue of the kidney and left ventricular myocardium were imaged in situ with a high speed, volume scanning, computerized x-ray tomographic imaging system. Volumetric measurements made by the random marking method correlated highly (r = 0.99) with measurements made by planimetry and with postmortem weight. These data indicate that the random marking method provides a rapid and accurate means of estimating tissue volume in serial tomographic sections.

Animals↗
PubMedDate not supplied

Analyze: a comprehensive, operator-interactive software package for multidimensional medical image display and analysis.

A comprehensive software package, called ANALYZE, has been developed (1) which permits detailed investigation and evaluation of multidimensional biomedical images. ANALYZE can be used with 3-D imaging modalities based on x-ray computed tomography, radionuclide emission tomography, ultrasound tomography, and magnetic resonance imaging. The software is written entirely in "C" and runs on standard UNIX workstations. The ANALYZE package features integrated, complimentary tools for fully interactive display, manipulation and measurement of multidimensional image data. The software architecture permits systematic enhancements and upgrades which has fostered development of a readily expandable package. It provides an effective shell for custom software prototyping and turnkey applications. This paper provides a general description of this software as well as specific details on the methodology employed to develop it, both conceptual and technical. Applications of the software are illustrated.

Image Processing, Computer-Assisted↗