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D C Chen

Publications and source records attributed to D C Chen.

At least 73 records · Page 4Linked to original sources
PubMed1987

Linear discriminant analysis of regional ejection fractions in the diagnosis of coronary artery disease.

We studied the application of linear discriminant analysis to the computer assisted interpretation of rest and exercise gated blood pool studies. Data were obtained in 45 patients in whom the presence or absence of coronary artery disease was determined by coronary angiography. Automated analysis of regional ejection fractions using a linear discriminant function (LDF) was compared to the fully automated calculation of global ejection fraction and to the subjective evaluation of wall motion. A LDF constructed from the data for the first 31 consecutive patients correctly classified 25/31 (81%). The change in global ejection fraction correctly classified 24/31 (77%) and wall motion analysis 25/31 (81%). In a distinct group of 14 patients the same LDF correctly classified 12/14 (86%), global ejection fraction 9/14 (64%) and wall motion analysis 10/14 (71%).

Coronary Disease↗
PubMed1987

Aortic ejection fraction: a new hemodynamic parameter and its relationship to aortic insufficiency.

Pulsations of the ascending aorta during fluoroscopy in patients with aortic insufficiency (AI) have been described. The authors present their observations of a similar phenomenon in patients who have AI undergoing scintiangiography. In addition, this paper describes a technique to validate and quantitate this finding. They studied 17 patients with documented AI and 14 subjects of a control group. First-pass studies were acquired in the RAO 15 degrees projection. Regions of interest were placed over the proximal aorta during systole and diastole. An aortic ejection fraction (AF) was determined. The calculated AEF data were correlated with the presence or absence of AI. The mean AEF from the 17 AI patients was 27.1 +/- 7.2%, while the mean for the non-AI group was 12.0 +/- 6.5% with p less than .001. An AEF of 18% separates the two groups with a sensitivity, specificity, and accuracy of 88%, 86%, and 87% respectively. Preliminary data demonstrate a mean reduction in AEF of 12.2 percentage points in 7 AI patients who underwent aortic valve replacement. The AEF may be a useful new parameter to evaluate hemodynamic changes associated with aortic valve replacement in patients with aortic insufficiency.

Adult↗
PubMed1986

Correlation of radionuclide imaging and diagnostic ultrasound in scrotal diseases.

A retrospective study was performed to evaluate the comparative usefulness of scrotal ultrasound imaging (SU) and radionuclide scrotal imaging (RSI) in 46 patients. The final diagnosis included four late phase and one early testicular torsion (TT), 11 acute epididymitis (AE), four subacute epididymitis (SE), six malignant tumors, ten hydroceles or other cystic lesions, and ten miscellaneous lesions. In patients with scrotal pain, 3/4 with late phase TT were correctly diagnosed by SU, while one with early TT and 11/15 with AE or SE were not diagnosed. All of them were correctly diagnosed with RSI except one with scrotal cyst. SU was able to separate cystic masses (n = 10) from solid masses (n = 9), but could not separate malignant from benign lesions. RSI had difficulty in separating cystic from solid lesions. We concluded that SU is useful in patients with scrotal mass to separate solid from cystic lesions. However, SU is unable to differentiate acute epididymitis from early testicular torsion. Therefore, in patients with acute scrotal pain, RSI should still be the first study performed.

Adolescent↗
PubMed1984

Scintigraphic features of giant cell tumor.

The scintigraphic appearance of giant cell tumor of bone in six patients is presented. Patients were studied by means of Tc-99m MDP bone scanning. On early blood pool and delayed imaging, markedly increased activity was noted, characteristically displaying a "ring" pattern that is readily discernible from patterns seen in bone cysts and nonosteogenic fibroma. The extent of the lesion, as judged by scintigraphic techniques, was roughly equal to estimates of extent by other radiographic modalities. Only one example of a different lesion mimicking giant cell tumor was encountered in over 100 cases of a variety of primary bone neoplasms reviewed. We conclude that giant cell tumor has a characteristic scintigraphic appearance.

Adult↗
PubMed1983

Minidose heparin in transurethral prostatectomy.

A double-blind prospective study was performed on 34 patients undergoing transurethral resection of the prostate (TURP). Seventeen patients, selected at random by computer, were given 5,000 units of subcutaneous heparin three hours preoperatively and every twelve hours thereafter for forty-eight hours. The other 17 received normal saline injections in a similar manner. All patients had pre- and postoperative lung scans. The blood loss was measured during and for seventy-two hours after surgery. There was no statistically significant difference in the bleeding in comparing the two groups. Two patients from the heparin group were diagnosed to have pulmonary emboli by lung scan preoperatively and showed no change postoperatively. In 1 patient from the control group an asymptomatic pulmonary embolism developed in the postoperative period. The use of subcutaneous heparin in TURP is safe and is recommended for patients with an increased risk of pulmonary embolism.

Double-Blind Method↗
PubMed1982

Transferrin receptors and gallium-67 uptake in vitro.

The relationship was studied between the number of transferrin-receptor positive cells and in vitro uptake of 67Ga and 125I-labeled transferrin in human cell lines, including two normal cell lines (WI-38 and foreskin fibroblasts), two transformed cell lines (AV-3 amnionic cells and Chang liver cells), and two neoplastic cell lines (HEp-2, larynx cancer and HeLa, cervical cancer). Transferrin receptors were determined by an indirect immunofluorescence technique based on their ability to bind purified human transferrin. Gallium-67 uptake was determined after a 24-h incubation of cells with Ga-67 in the presence and absence of transferrin (0-2.5 mg/ml). 125I-labeled transferrin uptake was also obtained after a 24-h incubation. The fraction of cells with transferrin receptors was low in normal cell lines (3% and 9%), intermediate with transformed cell lines (33% and 61%). Transferrin stimulated 67Ga uptake by all six cell lines. However, there was poor correlation between the number of transferrin-receptor positive cells and 67Ga uptake either in the presence (r = 0.21) or absence (r = 0.46) of human transferrin. Likewise, there was poor correlation between the number of transferrin-receptor positive cells and 125I-labeled transferrin uptake (r = 0.35). In contrast, the correlation between 67Ga uptake (in the presence of transferrin) and 125I-labeled transferrin uptake was highly significant (r = 0.96). These results suggest that human cell lines in culture are capable of both transferrin-dependent and transferrin-independent uptake of 67Ga.

Amnion↗
PubMed1982

Cerebrospinal fluid flow abnormalities in patients with neoplastic meningitis. An evaluation using 111indium-DTPA ventriculography.

Cerebrospinal fluid flow dynamics were evaluated by 111Indium-diethylenetriamine pentaacetic acid (111In-DTPA) ventriculography in 27 patients with neoplastic meningitis. Nineteen patients (70 percent) had evidence of cerebrospinal fluid flow disturbances. These occurred as ventricular outlet obstructions, abnormalities of flow in the spinal canal, or flow distrubances over the cortical convexities. Tumor histology, physical examination, cerebrospinal fluid analysis, myelograms, and computerized axial tomographic scans were not sufficient to predict cerebrospinal fluid flow patterns. These data indicate that cerebrospinal fluid flow abnormalities are common in patients with neoplastic meningitis and that 111In-DTPA cerebrospinal fluid flow imaging is useful in characterizing these abnormalities. This technique provides insight into the distribution of intraventricularly administered chemotherapy and may provide explanations for treatment failure and drug-induced neurotoxicity in patients with neoplastic meningitis.

Cerebral Ventriculography↗
PubMed1982

Radioisotope penogram in diagnosis of vasculogenic impotence.

A radioisotope technique to estimate penile blood flow is described. The radioisotope penogram is noninvasive and gives a dynamic evaluation of the arterial supply, venous drainage, and blood flow in the corporeal bodies. The penogram is a valuable adjunct in evaluation of patients with vasculogenic impotence.

Adolescent↗
PubMed1981

Utility of three-phase skeletal scintigraphy in suspected osteomyelitis: concise communication.

Three-phase skeletal scintigraphy, consisting of a radionuclide angiogram, an immediate postinjection "blood-pool" image, and 2--3 hr delayed images, was performed on 98 patients with suspected osteomyelitis. This procedure was evaluated by first interpreting only the delayed images, next the combination of "blood-pool" and delayed images, and finally the three-phase study. There was no change in the sensitivity (12/13 = 0.92) for detecting osteomyelitis, but the false-positive rate for osteomyelitis decreased from 0.25 (21/85) to 0.06 (5/85). In 21 of 64 patients (33%) with abnormal studies, the "blood-pool" image and/or the radionuclide angiogram led to a more accurate scintigraphic diagnosis. In 12 patients (19%) the "blood pool" alone was enough to achieve the correct final diagnosis and was used most often to identify noninfectious skeletal disease. In 9 patients (14%) the radionuclide angiogram was required for an accurate interpretation and was considered essential most often in cases of soft-tissue infection. Both radionuclide angiography and "blood-pool" imaging appear to augment the specificity of skeletal scintigraphy in patients with suspected osteomyelitis.

Adolescent↗
PubMed1980

The source of gallium-67 in gastrointestinal contents: concise communication.

The sources of Ga-67 in gastrointestinal (GI) contents, and factors affecting its secretion were studied in rats. To prevent loss of fecal Ga-67, the anus was sutured before intravenous injection of Ga-67 citrate. Secretion of Ga-67 into the contents of the GI tract was rapid, 3, 6, and 9% of the injected dose were secreted at 1, 6, and 24 hr after injection, respectively. In contrast, Ga-67 concentration in the GI tissues remained relatively constant throughout this period. Analysis of Ga-67 contents of various parts of the GI trace revealed that small intestine is its major source, contributing 60% while the bile contributes 20%, large intestine 10%, GI contents. In contrast, the serum unbound iron-binding capacity (UIBC) played an important role in the Gl secretion of Ga-67 reducing the serum UIBC reduced the Ga-67 secretion into GI contents.

Animals↗