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Biomedical subjects

L A Kramer

Publications and source records attributed to L A Kramer.

29 records · Page 2Linked to original sources
PubMed1996

Reliability of brain structure morphometry in hydrocephalic children using MR images.

To assess the ability of human operators to make decisions about region boundaries in significantly malformed brains, we performed a study of the reliability of morphometric measurements of specific brain structures from MRI in children with hydrocephalus and controls. Cross-sectional area measures of the corpus callosum, internal capsules and centrum semiovale, and volumes of the lateral ventricles were made in 50 children. Independent measurements were made by two raters on T1 and T2-weighted MR images. Pearson's correlation coefficients (r) and intraclass correlation coefficients (ICC) between the two rater's sets of measures were computed for each structure across all subjects. ICCs ranged from a low of 0.7502 to a high of 0.9895. All ICCs were significant at the p < .0001 level and were generally less than or equal to the corresponding Pearson's r value in every case. Therefore, the Pearson's r may overestimate the reliability. The results of this study support the claim that the ICC should be used rather than the Pearson's r when assessing interater reliability in situations where large between-group differences are present. In addition, the results show that brains malformed by disorders, such as hydrocephalus, can be reliably assessed using morphometric measures of MR images.

Brain↗
PubMed1995

PET and SPECT imaging for stereotactic localization.

Stereotactic localization using PET and SPECT has been used together with the Leksell stereotactic frame and the other imaging tools routinely provided to Gamma Knife radiosurgery sites. The accuracy of the measurements has been confirmed with CT and MR using a Radiation Analog Dosimetry phantom. The activity of the radionuclide solution placed in the tubes of Elekta Radiosurgery's MR imaging box is somewhat critical because the window levels chosen for the scan will affect the apparent size of the lesion. A technique is presented to resolve areas of activity more than about 12-14 mm apart, and it may prove useful in targeting epileptogenic sites in patients with medically intractable epilepsy.

Humans↗
PubMed1995

Beyond computer validation - a new role for quality assurance in systems development.

The Quality Assurance Unit (QAU) at Eli Lilly and Company is involved in the development of a new clinical pathology computer system in conjunction with the information systems area and the user area. This is the first time that the QAU had the opportunity to build our requirements into a new computer system. This is a new role for QA and includes both auditing and validation personnel who offer QA insights into issues. Benefits of QA involvement in the developmental process include saving time by building quality checks into the system, thus eliminating the need for manual review later in the process. Early resolution of issues leads to significant financial savings. Other benefits include improved communication among the three functional areas and a better understanding of the requirements and work processes. The team approach to the development of a new computer system results in a high-quality final product which meets all user and regulatory requirements, while also providing additional benefits to our organization.

Efficiency, Organizational↗
PubMed1993

Rare case of double aortic arch with hypoplastic right dorsal segment and associated tetralogy of Fallot: MR findings.

We report a rare case of double aortic arch with a hypoplastic right dorsal arch segment, which was also associated with tetralogy of Fallot. Accurate characterization of the hypoplastic right arch segment by MRI preoperatively determined the optimal surgical approach to releasing the symptomatic vascular ring. MRI was also useful in assessing and monitoring associated tracheomalacia.

Aorta, Thoracic↗
PubMed1988

A comparison of motor performance of preschoolers enrolled in mental health programs and non-mental health programs.

Recognizing that the etiologies of some major mental illnesses may be in the physical domain, this study described and compared the motor performance of 27 preschool children enrolled in mental health programs with 27 children enrolled in Project Head Start, a non-mental health program. The two groups were matched for age, race, and sex. The Gross and Fine Motor scales of the Peabody Developmental Motor Scales were administered to all subjects. On both measures the children enrolled in mental health programs scored significantly lower than the children enrolled in Project Head Start. In addition their scores were more variable. The results of this study support other findings suggesting that developmental delays may be characteristic of children with emotional disturbances.

Child, Preschool↗
PubMed1976

The audit and I.

Explore the source record for details and available documents.

Nursing Audit↗
PubMedDate not supplied

Chiasmal trauma: clinical and imaging considerations.

This report presents a patient who sustained closed head injury with chiasmal trauma. This uncommon injury may not be apparent on routine imaging studies. It is significant, not only from the visual standpoint, but also because of the association with serious conditions, such as panhypopituitarism, traumatic carotid aneurysm, carotid cavernous fistulae, and meningitis associated with leakage of cerebrospinal fluid. This report demonstrates that magnetic resonance imaging (MRI) is the best method for identifying chiasmal abnormalities.

Accidents, Traffic↗
PubMedDate not supplied

Estimation of CSF, white and gray matter volumes in hydrocephalic children using fuzzy clustering of MR images.

An algorithm and set of procedures for measuring volumes of cerebrospinal fluid (CSF), white matter, and gray matter from transaxial magnetic resonance images (MRI) of the brain are described. The algorithm is a variant of the fuzzy c-means clustering method for texture identification. This technique is used mainly to solve the problem of volume averaging of tissue compartments, but also has other advantages. It is fast, accurate, and relatively operator independent. Furthermore, it does not depend on statistical assumptions such as data normality, nor does it require any a priori heuristics. The procedure was tested successfully on imaged phantoms of known volume composition and compared with results achieved using a standard morphometric measurement approach. The procedure was also applied to brain MRIs of three clinically normal children and three age-matched children with hydrocephalus using both proton density and T2-weighted images. The algorithm was able to detect the expected increased amounts of CSF and decreased amounts of white matter characteristic of the hydrocephalic brain.

Algorithms↗
PubMedDate not supplied

Spectrum of congenital anomalies of the inferior vena cava: cross-sectional imaging findings.

Congenital anomalies of the inferior vena cava (IVC) and its tributaries have become more commonly recognized in asymptomatic patients. The embryogenesis of the IVC is a complex process involving the formation of several anastomoses between three paired embryonic veins. The result is numerous variations in the basic venous plan of the abdomen and pelvis. A left IVC typically ends at the left renal vein, which crosses anterior to the aorta to form a normal right-sided prerenal IVC. In double IVC, the left IVC typically ends at the left renal vein, which crosses anterior to the aorta to join the right IVC. In azygos continuation of the IVC, the prerenal IVC passes posterior to the diaphragmatic crura to enter the thorax as the azygos vein. In circumaortic left renal vein, one left renal vein crosses anterior to the aorta and another crosses posterior to the aorta. In retroaortic left renal vein, the left renal vein passes posterior to the aorta. In circumcaval ureter, the proximal ureter courses posterior to the IVC. Other anomalies include absence of the infrarenal IVC or the entire IVC. These anomalies can have significant clinical implications. Awareness of these anomalies is necessary to avoid diagnostic pitfalls.

Aorta, Abdominal↗