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Biomedical subjects

J N Yu

Publications and source records attributed to J N Yu.

7 recordsLinked to original sources
PubMed2000

Hyperlipidemia.

Coronary heart disease (CHD) is prevalent and often related to an unhealthy diet and hyperlipidemia. The diagnosis of hyperlipidemia should be carefully made, using more than one measurement in the manner described. An assessment of risks allows one to decide whom to treat. Patients with CHD should be treated aggressively but it is less clear how aggressive to be with patients without CHD. Diet and exercise recommendations are appropriate for almost all patients. For those for whom the benefit is greater than the potential risks, statins are first-line drug therapy and they appear to have beneficial effects aside from their lipid-lowering properties.

Adult↗
PubMed1995

Intermodality, retrospective image registration in the thorax.

UNLABELLED: The purpose of this study was to develop an accurate, retrospectively applicable procedure for registering thoracic studies from different modalities in a short amount of time and with minimal operator intervention. METHODS: CT and PET studies were acquired from six patients. The pleural surfaces in both image sets were determined by segmenting based on 50% of the maximum soft-tissue value in the study. These surfaces were converted into three-dimensional volumes and used to register the CT and PET studies in three dimensions using a sum of least squares fitting approach. The registered PET study was then displayed in a hot metal scale overlayed on top of the gray scale CT study. The accuracy of the fit was evaluated through a phantom study and preliminary clinical evaluation. RESULTS: A phantom study was performed to determine the limits of this technique. The accuracy was determined to be less than 2.3 mm in the x and y direction and 3 mm in the z direction. Preliminary clinical evaluation was also performed with encouraging results. CONCLUSION: This technique accurately registers PET and CT images of the thorax, retrospectively, without the need for external fiducial markers or other a priori action.

Aged↗
PubMed1994

Evaluation of emission-transmission registration in thoracic PET.

UNLABELLED: The intent of this investigation was to quantitate the amount of misregistration between PET emission and transmission scans of the thorax that occurs in a normal clinical environment. METHODS: The data from 17 FDG myocardial studies were evaluated. Prior to injection, a transmission study was acquired for 15 min using a 68Ge/68Ga ring source. The location of the cross-hairs from a laser alignment system was marked on the patient who was then removed from the scanner and injected with 10 mCi of FDG. After 45 min, the patient was placed back on the table and repositioned with the previously placed marks and a 15-min emission scan was acquired. The outline of the lungs on both the transmission and emission images was manually segmented. Both attenuation-corrected and noncorrected emission images were evaluated and the one that provided clearer visualization of the outline of the lungs was chosen for segmentation. The segmented contours of the transmission and emission scans were then registered with the method described by Pelizzari et al. using the transmission image as the "head" and the emission image as the "hat." The allowable transformations were x and y shifts and rotation in the transverse plane. RESULTS: Shifts in the x-axis averaged 2.4 mm (range: 0.2-7.3 mm, 80% less than 3.3 mm) with shifts in the y-axis averaging 2.6 mm (range: 0.1-8.7 mm, 80% less than 2.4 mm) and rotations in the transverse plane averaging 1.6 degrees (range: 0.2 to 5.1 degrees, 80% less than 2.4 degrees). A phantom study indicated that the accuracy of this method of evaluating misregistration was 2.35 mm and 1.81 mm in the x and y directions, respectively. CONCLUSION: Our preliminary evaluation indicates that careful application of laser alignment is an adequate method of registration in most cases.

Algorithms↗
PubMed1994

Night shift call systems in family practice residencies.

BACKGROUND: The number of hours worked by residents has come under scrutiny recently. One approach to decreasing the number of consecutive hours worked is the night shift call or night float system. METHODS: A survey was sent to the directors/administrators of all family practice residency programs. The survey inquired about their experience with the night shift call system (NSCS). Residencies with an NSCS were asked the reasons for its implementation, how it was implemented, its structure, and its effect on resident well-being, medical education, and patient care. RESULTS: Of the 295 programs responding, 15% had an NSCS in place, and 12% were considering its implementation. Resident satisfaction, alertness, personal life, quality of care, education, cross coverage, call frequency, reading, and studying improved in 50% or more of residencies. Conference attendance was unchanged. CONCLUSIONS: NSCSs are one way of reducing resident work hours without lengthening a residency. It can improve patient care, resident well-being, and postgraduate education.

Emergency Service, Hospital↗
PubMed1994

Pregnancy and extracranial shunts: case report and review of the literature.

This case involves a 32-year-old pregnant patient with a preexisting ventriculoperitoneal shunt. At term, she had a vaginal delivery with vacuum assistance, an epidural, and prophylactic antibiotics. Although there are no controlled studies validating the best course of management in such cases, there seems to be agreement that vaginal delivery can be attempted in the absence of other obstetrical indications for operative delivery. Obstruction of the shunt and, less commonly, abdominal cysts related to the distal end of the shunt are the principal obstetrical complications associated with a cerebrospinal shunt.

Adult↗