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Biomedical subjects

B C Lentle

Publications and source records attributed to B C Lentle.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of stress-only vs. stress/rest with technetium-99m methoxyisobutylisonitrile myocardial perfusion imaging.

Unlike conventional thallium-201 myocardial imaging, technetium-99m methoxyisobutylisonitrile (MIBI) requires separate stress and rest injections. We prospectively studied 148 consecutive patients referred for myocardial perfusion studies to determine the diagnostic value of rest images once normal exercise or dipyridamole tomographic images had been obtained. In patients referred with no history of previous myocardial infarction in whom the diagnosis of coronary artery disease was suspected, 45 of 109 (41%) patients had normal stress tomographic images. Obtaining rest images did not alter the final interpretation in any of these cases. From this we infer that in patients with normal images after exercise or dipyridamole administration and no past history of myocardial infarction, 99mTc-MIBI rest images are not required. This provides several advantages including increased speed of diagnosis, decreased patient radiation exposure, improved cost efficiency and decreased demand on tomographic camera time.

Contrast Media↗
PubMed1991

Intracranial extramedullary hematopoiesis. CT and bone marrow scan findings.

This case concerns a patient with intracranial extramedullary hematopoiesis (EH) suspected on a CT scan and subsequently confirmed with In-111 chloride and Tc-99m SC bone marrow scans. The bone marrow scans also provided additional information by demonstrating other sites of EH in the paravertebral tissues and bone marrow expansion into the distal extremities.

Adult↗
PubMed1991

The role of bone scintigraphy in the evaluation of talar dome fractures.

We undertook a retrospective study of 122 patients with ankle pain to determine the accuracy of bone scintigraphy using 99mTc-methylene diphosphonate (MDP) for detection of osteochondral talar dome fractures (OCTDF). Plain radiographs, which were available in 97 patients, had not revealed any abnormality in the talar dome. Bone scintigraphy was followed by CT, which was considered to be the reference test in diagnosing OCTDF. Analysis of our data showed that when the bone scan findings in the two highest confidence categories (high and moderate probability) were accepted as abnormal, the sensitivity and the specificity of the test were 0.94 and 0.76, respectively. Although CT is mandatory to establish the stage of OCTDF, it cannot be used routinely due to its high cost. Bone scintigraphy appears to be a good screening procedure that will identify patients who are likely to benefit from further radiographic studies such as CT. These findings are subject to further confirmation in a prospective study.

Adolescent↗
PubMed1991

Imaging of diffuse lung diseases. Past, present, and future.

For many years the plain chest radiograph was the only imaging modality used in the assessment of patients who had diffuse lung disease. Presently, high resolution computed tomography (CT) and lung scintigraphy play a major role in the assessment of these patients. Use of magnetic resonance (MR) imaging in the assessment of the lung parenchyma has been limited by poor signal-to-noise ratio and physiologic motion. Recent improvements in technique, however, have allowed assessment of patients with diffuse lung disease. It is likely that MR imaging will play an increasing role in the assessment of these patients in the near future.

Humans↗
PubMed1990

Computerized tomography versus perfusion lung scanning in canine radiation lung injury.

Computerized tomographic (CT) measurements of lung density were obtained before and serially after thoracic irradiation in dogs to detect the alterations caused by radiation therapy. Fourteen mongrel dogs were given either 2000 cGy (Group A, 10 dogs, right lower zone irradiation), 1000 cGy (Group B, 2 dogs, right lower zone irradiation), or 500 cGy (Group C, 2 dogs, right lung irradiation) in one fraction. Once before and bi-weekly after irradiation, the anesthetized dogs had thoracic CT scans. CT numbers for the irradiated area were compared to their preirradiation control values. Macro-aggregated albumin (MAA) perfusion lung scans were also obtained before and at weekly intervals after irradiation and were evaluated visually and quantitatively for abnormalities. When both these tests were abnormal, or at the end of the scheduled study, the dogs were sacrificed to confirm radiation lung injury histologically. Our results showed that CT numbers (as a measure of tissue density) were higher with higher doses of radiation. Among all the techniques used, only the quantitative assessment of macro-aggregated albumin perfusion scan detected abnormalities in all the dogs given 2000 cGy. Their abnormalities correlated well with the presence of radiation lung damage histologically, however, the applicability of these methods in the detection of early injury has to be further evaluated.

Animals↗
PubMed1990

Interactive three-dimensional region of interest analysis of HMPAO SPECT brain studies.

An interactive computer program has been developed to align a three-dimensional region of interest (ROI) model to technetium-99m-hexamethylpropylenamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) studies of the brain. The ROI model subdivides the human brain into fourteen discrete regions. A study was performed to determine normal ranges for HMPAO uptake in the ROIs defined by the model, and to assess the relative interobserver variability using the fitting program. HMPAO SPECT studies of twelve normal volunteers were independently analyzed by four observers. Small but significant differences between operators occurred primarily because of difficulty in defining the angle of the orbitomeatal plane on sagittal SPECT images. Despite this difficulty, the program and model have proven useful in defining ranges for normal cerebral perfusion in a healthy adult population. A study of a small group of patients with Alzheimer's dementia suggests that this procedure may be of use in the diagnosis of this disease.

Adult↗
PubMed1987

Gallium-67 scintigraphy and non-small-cell bronchogenic carcinoma: a quantitative in-vivo predictive assay?

Gallium-67 scintigraphy has been of limited use in detecting lung cancers and micrometastases. To study its potential for determining the aggressiveness of a cancer, we reviewed the charts of 44 patients with non-small-cell bronchogenic carcinoma who had not been receiving treatment when 67Ga scintigraphy was performed. The mean length of survival for the 18 patients with low or little uptake of the tracer, corrected for tumour size, was 19.7 months, and for the 26 with high uptake 9.4 months (p less than 0.01). Such in-vivo predictive assays may be a rational goal for tumour scintigraphy.

Carcinoma, Bronchogenic↗
PubMed1987

Biological behavior of 67Ga-citrate in New Zealand White rabbits.

The pharmacokinetics, protein binding, excretion and tissue distribution of 67Ga after the administration of 67Ga-citrate to New Zealand White rabbits is described. Data for 67Ga blood levels were best described by an equation with three exponential components exhibiting half lives of 0.25 h, 7.4 h and 19.5 h, with almost all of the activity in a protein bound form. Weekly urinary excretion (approximately 27%), possibly in a metabolized form, and fecal elimination (approximately 20%) were greater than the reported values in man, but there was a similar organ distribution pattern in these animals as in man. The overall biological handling was judged to be similar in both species making the rabbit a suitable model for further 67Ga-citrate studies in vivo.

Animals↗
PubMed1987

Detecting bone marrow metastases at the time of examining the liver with radiocolloid.

In a prospective study of 200 different consecutive patients with cancer, the bone marrow of the lumbar spine and pelvis has been examined at the time of obtaining a radiocolloid examination of liver and spleen. The images were examined "blind" by three observers who all agreed about the findings in 177 (89%) of the patients. Agreement by any two was considered to be definitive. The radiocolloid marrow examinations in this selected population had an accuracy of 0.97, sensitivity of 0.80, and specificity of 0.98 in diagnosing metastatic disease when validated by all other available evidence, or follow-up. Of the patients thus examined, 16 (8%) had abnormal marrow scan findings reflecting metastatic disease, eight (4%) at the time radiographs were normal, and two at the time bone scintigraphy was normal. Excluding patients with bowel cancer, in whom the detection rate was zero, 16 (12.4%) marrow examinations were abnormal. As a result we now obtain "saturated" images of the marrow incidental to radiocolloid examinations of the liver and spleen in patients with cancer other than that of the bowel.

Bone Marrow Diseases↗
PubMed1986

Immediate and delayed effects of cis-platinum treatment on the short term biodistribution of 67Ga-citrate in mice.

The co-administration of a single medium toxic dose (5 mg/kg) of the chemotherapeutic drug cis-platinum (cis-Pt) with 67Ga-citrate was found to have minimal effects on the 3 h tissue distribution of the radiopharmaceutical in mice. When the same drug dose was given at two day intervals preceding the co-administered dose, virtually all tissues accumulated 67Ga to a greater extent. The tissue distribution of radiolabeled cis-Pt supported the development of drug-induced renal dysfunction as the primary cause.

Animals↗
PubMed1986

Effect of cis-platinum treatment on 67Ga-citrate localization and elimination in rabbits.

The treatment of rabbits with a typical dosage schedule of the chemotherapeutic drug cis-platinum resulted in an increased whole body retention of 67Ga-citrate due to decreased urinary and fecal excretion. The biodistribution of the tracer was also affected with most tissues showing greater accumulation. These changes are primarily related to drug-induced renal dysfunction, but other factors may also be involved.

Animals↗
PubMed1986

Effect of cis-platinum on the protein binding and pharmacokinetics of 67Ga-citrate.

Cis-platinum, a widely used chemotherapeutic drug, and K2PtCl4, a related complex, were found to inhibit the in vitro protein binding of 67Ga to human transferrin in isolated solution but not to whole serum. Cis-platinum treatment of rabbits resulted in enhanced protein binding and delayed blood clearance of subsequently injected 67Ga-citrate. These effects are related to the toxicity of the drug in vivo.

Animals↗