PubMed Health⌕ Search

Biomedical subjects

W K Chu

Publications and source records attributed to W K Chu.

At least 37 records · Page 2Linked to original sources
PubMed1988

Artifacts and diagnostic pitfalls on magnetic resonance imaging: a clinical review.

High field MRI of the brain occasionally exhibits imaging artifacts; most artifacts are obvious and easily recognized, but some are subtle and mimic disease. A thorough understanding of brain MRI artifacts is important to avoid potential diagnostic pitfalls. Some imaging techniques or procedures could be utilized to remove or identify artifacts. These include additional projections, different pulse sequence, and 90 degree shift of phase-encoding gradient. The use of respiratory gating or cardiac gating may also improve image quality by reducing some of the motion-related artifacts.

Adolescent↗
PubMed1987

Limb-length discrepancy measured with computerized axial tomographic equipment.

A simple, rapid, and accurate method for measuring limb-length discrepancies with computerized axial tomographic equipment is described. With this method less irradiation is delivered and some of the errors of computation are eliminated, compared with conventional methods. The costs of the technique are comparable with those of scanograms. The method is particularly applicable in the patient who has contracture of a joint.

Adult↗
PubMed1986

Diagnostic pitfalls and artifacts in high field magnetic resonance imaging.

Similar to all other medical imaging modalities, magnetic resonance imaging (MRI) has various artifacts. Some artifacts are easily recognizable such as motion, while some are not very obvious and even sometimes mimic pathologic conditions. These artifacts, if not differentiated, could easily become diagnostic pitfalls for radiologists and lead to erroneous conclusions. We have studied some of the imaging artifacts associated with a 1.5 tesla MRI scanner and report some cases who could become potential diagnostic pitfalls. Causes for these artifacts, although some not proven, are also presented.

Artifacts↗
PubMed1986

Retreatment of recurrent cystic craniopharyngioma with chromic phosphorus P 32.

A cystic craniopharyngioma in a two-year-old boy recurred six months after surgery and postoperative external-beam radiotherapy. Successful retreatment was accomplished with radioisotope injection of 0.5 mCi of chromic phosphorus P 32 into the intracranial cyst, which delivered approximately 300.00 Gy to the cyst wall. The patient's symptoms were relieved, and he is without evidence of disease or cystic fluid accumulation four years after intracavitary (32)P irradiation.

Child, Preschool↗
PubMed1985

Artifacts and pitfalls of high-resolution CT scans.

Artifacts on CT images have been observed since the introduction of CT scanners. Some artifacts have been corrected with the improvement of technology and better understanding of the image formation and reconstruction algorithms. Some artifacts, however, are still observable in state-of-the-art high-resolution scans. Many investigations on CT artifacts have been reported. Some artifacts are obvious and some are similar to patterns commonly associated with pathological conditions. The present report summarizes some of the causes of artifacts and presents some artifacts that mimic pathology on clinical scans of the head and spine. It is the intention of this report to bring these artifacts and potential pitfalls to the attention of the radiologists so that misinterpretation can be avoided.

Brain Diseases↗
PubMed1984

Ocular volume measured by CT scans.

Newer CT scans have greatly enhanced oculometric research and made it possible to measure ocular dimensions. With these measurements, ocular volume can be more accurately estimated to understand its relationship with age and sex. One hundred CT orbit scans with presumed normal eyes were used for the data base. The mean values and normal variations of ocular volumes at various ages in both sexes are presented. Rapid growth of the eyeball was noted during the first 24 months of age. It reached its peak between the ages of 18 and 30 years of age, after which there was a reduction. Results may be of help in recognizing eye abnormalities such as microophthalmus and macrophthalmia.

Adolescent↗
PubMed1984

CT measurements of cranial growth: normal subjects.

Growth patterns of the cranium measured directly as head circumference have been well documented. With the availability of computed tomography (CT), cranial dimensions can be obtained easily. The objective of this project was to establish the mean values and their normal variance of CT cranial area of subjects at different ages. Cranial areas and its long and short axes were measured on CT scans for 215 neurologic patients of a wide age range who presented no evidence of abnormal growth of head size. Growth patterns of the cranial area as well as the numeric product of its linear dimensions were determined via a curve fitting process. The patterns resemble that of the head circumference growth chart, with the most rapid growth observed in the first 12 months of age and reaching full size during adolescence. It is believed that the availability of such reference, in addition to the head circumference measurement, will be valuable to the CT reviewer in determining the growth status of head size.

Child, Preschool↗
PubMed1984

CT measurements of cranial growth: microcephaly.

Computed tomographic (CT) head scans were measured to determine the cranial dimensions of four children with microcephaly. These measurements were compared with cranial dimensions of normal children. CT proved to be useful in determining the developmental status of children with neurologic problems relative to their normal counterparts on the basis of cranial dimensions.

Child↗
PubMed1983

Comparative hemodynamic effect of metrizamide and Renografin 76 in infants with congenital heart disease.

Twenty patients under the age of 2 years with suspected congenital heart disease received alternately Renografin 76 and metrizamide for angiocardiography. The dose was 2.0 ml/kg per injection for both contrast media into the left ventricle. Metrizamide induced slightly lesser change in heart rate, peak systolic pressure, and peak end-diastolic pressures. Serum osmolality, hematocrit, and serum electrolytes were affected equally by the contrast media. Metrizamide was well tolerated by the neonates with congenital heart disease and its radiopacity was adequate for diagnostic purposes. At the doses administered, metrizamide does not seem to have any great advantage over Renografin 76 for angiocardiography in infants with severe congenital heart disease.

Angiocardiography↗
PubMed1982

A two-year reject/retake profile analysis in pediatric radiology.

With increasing interest in the use of reject/retake analysis as an integral part of a routine quality assurance program in diagnostic radiology comes the need for a better understanding of the information obtained. The present study investigated the reject/retake profiles in a pediatric radiology department on a long-term basis. Retake profiles have been continually analyzed for a period of 24 months. Emphasis of the analysis were placed upon understanding the characteristics of the profiles observed and the effectiveness of the corrective actions implemented. The analysis indicated that after the implementation of a comprehensive quality assurance program, the overall rejection profile is predominantly determined by the rate of positioning errors.

Pediatrics↗