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Biomedical subjects

W J Shih

Publications and source records attributed to W J Shih.

At least 163 records · Page 9Linked to original sources
PubMed1990

I-123 HIPDM planar brain images demonstrating crossed cerebellar diaschisis.

I-123 HIPDM or IMP brain planar images, as well as SPECT images, have been useful in the detection of large lesion(s) of the cerebral cortex. Planar imaging may be useful not only for cerebral lesions, but also for a cerebellar abnormality and in certain clinical situations, such as phobia to a gantry or being too heavy for the imaging table, when SPECT imaging cannot be performed. The authors concur that a large cerebral lesion can be detected by planar images; in addition, cerebellar lesions, such as the presence of crossed cerebellar diaschisis (CCD), may be detectable by planar imaging using I-123 HIPDM. This article presents a patient with a large cerebral infarct detected by planar imaging whose CCD has been demonstrated by planar images.

Aged↗
PubMed1990

Tc-99m HMPAO SPECT of the brain in the neonate.

A brain scan with Tc-99m hexamethylpropyleneamineoxime (HMPAO) performed on a neonate demonstrated normal localization only in the sensorimotor cortex, basal ganglia, and cerebellum. This pattern of localization is remarkably similar to previously published PET images of the neonate. Because Tc-99m HMPAO is readily available and has biochemical and physical characteristics that are suitable for perfusion imaging of the brain, it likely will become a major imaging agent in nuclear medicine. Normal scan findings in the neonatal age group with Tc-99m HMPAO have not been previously reported because of limited clinical use to date.

Brain↗
PubMed1990

I-123 hydroxyiodobenzyl propanediamine (HIPDM) cerebral blood flow imaging demonstrating transtentorial diaschisis.

To assess the clinical significance of transtentorial diaschisis (TTD) as demonstrated by I-123 HIPDM brain imaging, SPECT and/or planar images of 35 patients with stroke, 26 patients with Alzheimer's disease (AD), 2 patients with Creutzfeldt-Jakob disease (CJD), and 1 patient with a schizoaffective disorder were analyzed. TTD was observed in 21 of the 35 patients with strokes. In 13 stroke patients, TTD was associated with large infarcts in the middle cerebral artery (MCA) territory; in the remaining 8 stroke patients, TTD was associated with internal capsule and/or basal ganglia infarcts. TTD was not associated with small occipital or parietal infarcts. Despite cortical perfusion decrements, TTD was not seen in the AD patients, the CJD patients, or the patient with schizoaffective disorder. It is concluded that 1) TTD frequently occurs following cerebral infarct of the MCA territory (60% of the patients in this sample); 2) absence of TTD in the presence of a large cerebral perfusion abnormality may represent neuronal dysfunction of the cerebral cortex; and 3) the presence of TTD without a significant cortical perfusion abnormality may indicate basal ganglia and/or internal capsule infarct.

Alzheimer Disease↗
PubMed1990

Serum osteocalcin measurements in prostate carcinoma patients with skeletal deposits shown by bone scintigram: comparison with serum PSA/PAP measurements.

The correlation of technetium-99m-HMDP bone scintigraphic findings, serum osteocalcin as a measure of bone turnover and prostate-specific antigen (PSA) and/or prostate acid phosphatase (PAP) was determined in 19 men with bone metastasis due to prostatic carcinoma. Six of the 19 patients with metastases on bone scan showed elevation of osteocalcin. These patients had extensive metastatic disease. All 19 men with positive bone scans had high serum PSA and/or PAP levels. Serum osteocalcin measurement is less sensitive to detection of bone deposits than PSA/PAP measurements (p less than 0.0008).

Acid Phosphatase↗
PubMed1990

Iodine-123-HIPDM lung imaging in pulmonary vein-banded pulmonary hypertension.

To evaluate the use of N,N,N'-trimethyl-N,-[2-hydroxy-3-methyl-5 iodobenzyl-1, 3 propanediamine iodine-123 (HIPDM) in lung imagings for the diagnosis of individual pulmonary vein stenosis, 14 single-pulmonary vein-banded rats underwent lung imaging. After i.v. injection of 250-300 microCi [123I]HIPDM lung images were recorded at 2 min by a gamma camera interfaced with a PDP computer. Banded lung demonstrated higher [123I]HIPDM radioactivity than that of nonbanded lungs. The activity ratio of banded-to-nonbanded lungs ranged from 4.0 to 1.22 (average 1.62). Technetium-99m-macroaggregated albumin (MAA) lung images showed decreased perfusion in banded lung, and normal perfusion in the nonbanded lung. Postmortem microscopic changes in pulmonary arteries and veins were compatible with the elevated pulmonary artery and venous pressure in vein-banded lung. Whether the high uptake of [123I]HIPDM in banded lungs relates to endothelial receptors for HIPDM is unknown. Nevertheless, the finding of high lung uptake in banded lung in [123I]HIPDM lung imaging may be potentially used to diagnose individual pulmonary vein stenosis.

Animals↗
PubMed1989

The analysis of titration studies in phase III clinical trials.

Clinical trials commonly employ the titration design for certain drugs such as antihypertensives. In a Phase III trial the design has purposes distinct from those of a Phase I or II trial, as well as from those of a trial with a parallel design. In this paper we compare the titration design with the usual parallel design in their respective purposes for Phase III trials, explore the relevant questions addressed, and examine typical data from such trials. We also discuss work which focuses primarily on the Phase I or II titration trials. We formulate the problem in the framework of one-way contingency table augmented with incomplete data and obtain the maximum likelihood estimates of the parameters and their estimated variances/covariances via the EM algorithm. An example of a Phase III study of an antihypertensive agent illustrates the proposed procedure.

Analysis of Variance↗
PubMed1989

Extensive extraosseous localization of bone imaging agent in a patient with renal failure and rhabdomyolysis accompanied by combined hypercalcemia and hyperphosphatemia.

Four sequential Tc-99m pyrophosphate (PYP) imaging studies were performed in a 28-year-old man with high fever and exudate pharyngitis associated with renal failure. Radiotracer localization in the left ventricle (LV), lungs, kidneys, and skeletal muscles were seen in two, initial imaging studies. In the second and third imaging studies, area of increase in activity was seen in the left-sided bowel. In studies done two months later (in the third study), the radioactivity in the skeletal muscles was no longer seen. Studies obtained nine months (in the fourth study) after the first imaging showed less radiotracer localization in the LV, lungs, and kidneys as compared to that seen in the initial study. Myocardial necrosis and microcalcification were proved by LV biopsy. The exact mechanism of extraosseous bone-imaging agent localization is unknown. However, this phenomenon may be related to renal failure, rhabdomyolysis, hypercalcemia, hyperphosphatemia, or elevated parathyroid hormone. The Tc-99m PYP imaging study is useful and sensitive in the detection of extraosseous tissue calcification and monitoring of the disease process.

Acute Kidney Injury↗
PubMed1989

Examples of complementary roles of abdominal CT and radiocolloid liver imaging.

Two cases are reported in which well-defined lesions of the liver were seen in radiocolloid liver imagings but not in the concurrent abdominal CT images. The results of autopsy confirmed the diagnosis of hepatoma in one and metastatic disease in the other. The third case, referred for a Tc-99m SC liver-spleen image because of a suboptimal abdominal CT owing to artifact, showed a normal liver. In certain clinical situations, radiocolloid imaging provides a complementary role to CT in the detection or confirmation of hepatic lesions and, in occasional patients, is superior to CT.

Aged↗
PubMed1989

Correlation of prostate-specific antigen and technetium-99m HMDP bone imaging.

For an evaluation of the clinical utility of prostate-specific antigen (PSA), 32 prostatic carcinoma patients (ages 54-76) and 13 nonprostatic carcinoma patients (ages 60-70) underwent PSA measurements and bone imaging. At the time of bone imaging, each patient's PSA value was measured by a monoclonal immunoradiometric assay. All 13 nonprostatic carcinoma patients (11 bronchogenic, 1 colon, and 1 urinary bladder) gave normal PSA values, although 6 had metastatic bone disease. The 32 prostatic cancer patients were divided into 2 groups of 16 each; PSA levels in Group 1 were abnormal (greater than or equal to ng/ml): PSA levels in Group 2 were normal (less than 4 ng/ml). In Group 1, bone images of 14 patients showed bone metastases; 6 of the 14 showed progression of metastases in a 6- to 12-month period. Two patients in Group 1 were negative for skeletal metastases. Twelve patients in Group 2 were negative for skeletal metastases; bone imaging in 1 showed regression of skeletal metastases; and 3 patients had unchanged bone lesion(s). The data indicate that PSA measurements may enhance bone imaging interpretation and provide valuable clinical monitoring of prostatic carcinoma. In the case of a patient with positive bone imaging and an unknown primary, PSA measurements may definitively determine if metastases originated from prostatic carcinoma.

Aged↗
PubMed1989

Prediction approaches to sequentially searching for an optimal dose.

The search for an optimal dose of a drug has been investigated in a sequential setting to ensure the safety level by Eichhorn and Zacks (1973, Journal of the American Statistical Association 68, 594-598; 1981, Communications in Statistics--Theory and Methods A10, 931-953), Eichhorn (1974, Communications in Statistics 3, 263-271), and Robinson (1978, Biometrika 65, 75-78). In this paper the procedure proposed by Robinson is given a new interpretation in terms of mean coverage tolerance prediction, and a new procedure in terms of guaranteed coverage tolerance prediction is proposed. The new procedure has better properties and is more stringent, and hence more desirable for safety consideration.

Biometry↗
PubMed1988

Application of I-123 HIPDM as a lung imaging agent.

N,N,N'-Trimethyl-N'-(2-Hydroxyl-3-Methyl-5-123I Iodobenzyl)-1,3-Propanediamine.Hcl (123I-HIPDM) has been used for diagnosis of patients with strokes and dementias. Since this radiopharmaceutical is also accumulated in the lung, we routinely performed a lung image or images immediately prior to cerebral planar and SPECT images after a 3-5 mCi 123I-HIPDM injection. During the past 14 months, we obtained 78 (age from 41 to 92 years, average 66.7 +/- 8.9 years; 64 males, 14 females) suspected stroke or dementia patients' lung images. All lung images were correlated to chest X-ray (CXR) or CT and other clinical data. Sixty five of 78 patients had normal lungs showing homogeneous distribution of activity throughout the lungs which correlated well to normal CXR and/or CT studies. Abnormal scintigraphic patterns of the 13 patients included lung defect (5 bronchogenic carcinoma with or without atelectasis) and decreased uptake in apices (8 chronic obstructive pulmonary disease). The findings of pulmonary intrathoracic pathologies on lung images with 123I-HIPDM suggests further evaluation of the agent for detection of localized pulmonary diseases and pulmonary physiological studies relating to amine metabolism.

Adult↗
PubMed1988

Intense bone imaging agent uptake in the soft tissues of the lower legs and feet relating to ischemia and cold exposure.

We present a patient with diffuse and intense uptake in the soft tissues of both lower legs and feet seen on 99mTc-HMDP bone scintigraphy. This finding presumably resulted from compromised blood supply to the lower legs plus a cold environment. The extraosseous bone imaging agent localization was presumably related to an existing ischemic condition that was exacerbated by cold. Differential diagnosis of the scan pattern should be differentiated from the artifact of socks contaminated by radioactive urine.

Aged↗