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Biomedical subjects

K R Lee

Publications and source records attributed to K R Lee.

At least 163 records · Page 9Linked to original sources
PubMed1982

Three-dimensional computer reconstructions of brain lesions from surface contours provided by computed tomography: a prospectus.

We present a prospectus on the use of computer graphics for the three-dimensional reconstruction and visualization of brain lesions from computed tomographic head examinations, including an algorithm that utilizes surface contour information to reconstruct and display three-dimensional anatomical sites. We provide examples of the use of this algorithm. We offer an algorithm for estimation of the volume and surface area of anatomical sites. The advantages and disadvantages for the clinical use of these algorithms are discussed.

Adenoma, Chromophobe↗
PubMed1982

Diagnosis of pericardial effusion by computed tomography.

We assessed the diagnostic utility of computed tomography (CT) in the detection of pericardial effusion by using a dog model in which the amount and type of pericardial fluid were controlled and by obtaining CT scans on patients with suspected pericardial effusion prior to pericardiocentesis. The experimental studies showed that CT was capable of detecting pericardial effusion composed of serous fluid or saline in amounts as small as 50 ml. However, the hemopericardium was radiographically isodense with the heart and difficult to detect by CT unless the epicardial fat pad was identified or intravenous contrast enhancement of the heart was used. CT clearly demonstrated the presence of pericardial effusion in all six patients studied prior to successful pericardiocentesis or pericardiectomy. We conclude that CT is a sensitive noninvasive method which can be used for the diagnosis of pericardial effusion.

Adult↗
PubMed1982

A peripheralized digital image management system: prospectus.

The number of diagnostic radiology examinations being performed on digitally formatted imaging equipment is continually increasing. However, most digital data are recorded as analogue images and the films stored in a central file. The dynamic range of raw digital data is lost. Currently, the space and cost requirements for storage of all digital data have discouraged most users from attempting it. This article presents the concepts and describes the requirements and initial fabrication of a system that will capture and retain all digital data using a network of peripheralized image acquisition, display, and storage devices. Any piece of digitally formatted equipment can be interfaced into the system. A real-time computer capability provides that any digital examination can be reviewed at any display station for up to 10 days.

Computers↗
PubMed1981

Continuous image recording using gray-tone, dry-process silver paper.

A method of recording continuous gray-tone images on dry-process silver paper from raster-scan video signals is described. The Tektronix 4634 image-forming module uses a fiber-optic faceplate cathode-ray tube to couple the light output onto the recording paper. The latent image is heat developed and presented in sheet form. An initial comparison between dry silver paper and conventional film for video-generated computed tomography and nuclear medicine examinations, shows little apparent difference in image quality. Considerable cost savings are possible when using dry silver paper. Additional cost savings are possible if multiple images can be recorded on each dry silver sheet.

Costs and Cost Analysis↗
PubMed1980

Conversion of percutaneous ureteral stent to indwelling pigtail stent over guidewire.

A ureteral stent placed percutaneously through a nephrostomy can be readily exchanged endoscopically for a ureteral indwelling pigtail stent over a percutaneous guide wire. Percutaneous antegrade stent placement can sometimes be accomplished when retrograde placement cannot. We report 10 successful conversions to indwelling stent in 11 cases. In 1 case the percutaneous guide wire could not be retrieved endoscopically because of a bleeding tumor in the bladder. No serious difficulties or complications were encountered. The percutaneous approach offers an alternative method of providing internal urinary diversion if retrograde ureteral indwelling stent placement has failed.

Adult↗
PubMed1980

Comparison of computed tomography and ultrasound in abdominal staging of renal cancer.

The relative accuracy of computed tomography (CT) and ultrasound in abdominal staging of renal cancer was determined in 22 patients. CT is capable of detecting tumor invasion of perinephric fat and adjacent muscles, which cannot usually be shown by ultrasound. While both CT and ultrasound demonstrate venous and retroperitoneal tumor extension, CT is more reliable since bowel gas not infrequently obscures the retroperitoneum on ultrasonic scanning. However, ultrasound will often provide valuable information; and whenever a solid renal mass is detected by echography using prone scans, abdominal scans should be obtained for staging pruposes.

Adenocarcinoma↗
PubMed1980

Subcutaneous implantation of percutaneous ureteral stents.

The authors describe their experience with subcutaneous implantation of percutaneous ureteral stents. Three of the five procedures were complicated by infection, urine leak and/or chronic drainage at some time during their course. One patient developed pressure changes of the skin overlying the implanted tube. The problems encountered in this initial experience are avoidable. Subcutaneous implantation of percutaneous ureteral stents can be useful in the management of appropriate patients.

Catheters, Indwelling↗
PubMed1980

CT for intracavitary radiotherapy planning.

Twenty-two patients with malignant uterine tumors were examined with computed tomography (CT) for treatment planning after insertion of an afterloading Fletcher applicator. The CT findings maximized the individualization of treatment planning, including the number, dosage, and loading arrangement of radioactive sources. Artifacts were produced by the metal; but in most cases the scans accurately portrayed the three-dimensional anatomic relationship of the applicator, uterus, and neighboring vital structures. The CT information made it possible to calculate dose distribution more rapidly and accurately for both intracavitary therapy and combined intracavitary and external therapy. Unsuspected uterine perforation was detected by CT in one case.

Aged↗
PubMed1980

Chronic gastrointestinal bleeding from ileal varices after total proctocolectomy for ulcerative colitis: correction by mesocaval shunt.

This report describes a 48-yr-old woman who had undergone proctocolectomy and ileostomy for ulcerative colitis. Subsequently, numerous episodes of bleeding via the ileostomy occurred during a 24-mo period. Despite numerous procedures, including upper gastrointestinal endoscopy, ileoscopy. celiac and superior mesenteric arteriography, and exploratory laparatomy, a bleeding site was not identified. However, a detailed arteriographic examination with special venous phase studies clearly demonstrated ileal varices. A mesocaval shunt resulted in a marked reduction in portal pressure, and the patient had experienced no recurrent bleeding over a 24-mo period. The importance of obtaining appropriate venous phase studies during arteriography is emphasized because it is critical in establishing the correct diagnosis.

Angiography↗
PubMed1979

Computed tomographic and ultrasonic appearances of primary carcinoma of the common bile duct.

Two patients with obstructive jaundice due to surgically proved primary carcinoma of the common bile duct were examined by CT and ultrasound. The combination of the two modalities showed dilatation of the extrahepatic biliary system and the main pancreatic duct. The diagnosis of primary bile duct carcinoma is suggested by these findings in the presence of a normal pancreatic head, although similar findings may occur with a small pancreatic or ampullary carcinoma.

Adult↗
PubMed1979

Computed tomography in the diagnosis of renal carcinoma complicating Hippel-Lindau syndrome.

Four patients on long-term follow-up for Hippel-Lindau syndrome (HLS) are presented. All had undergone nephrectomy for renal carcinoma; in 2, carcinoma subsequently developed in the remaining kidney. Because of the tendency of these tumors to develop bilaterally, wide local resection is preferable to radical nephrectomy if the tumors can be diagnosed when small and noninvasive. CT is currently the most accurate method of regularly screening patients with HLS for asymptomatic renal carcinoma.

Adult↗
PubMed1979

Comparison of computed tomography and other imaging modalities in the evaluation of musculoskeletal tumors.

An algorithmic approach for the evaluation of musculoskeletal tumors is proposed on the basis of a prospective comparison of different imaging techniques in 50 unselected patients. Conventional radiography was superior to other techniques in predicting the nature of primary bone tumors. Computed tomography proved the most effective method for assessing the extent of musculoskeletal tumors and therefore had a significant influence on management in 66% of patients studied. CT was more informative than angiography and also provided more anatomical detail than ultrasound. Radionuclide scanning was mainly of value in detecting unsuspected skeletal metastases in patients with apparently solitary skeletal lesions.

Adolescent↗