Biomedical subjects

H F Corbus

Publications and source records attributed to H F Corbus.

10 recordsLinked to original sources

PubMed1997

Diagnostic usefulness of lung SPET in pulmonary thromboembolism: an outcome study.

The lung single photon emission tomographic (SPET) images of 985 consecutive patients referred for suspected pulmonary embolism were correlated with clinical outcome and angiography to evaluate the clinical usefulness of lung SPET compared to conventional planar ventilation/perfusion lung imaging. SPET interpretations followed the revised PIOPED criteria and clinical outcome was determined from referring physicians, hospital records, direct patient contact and county hall records. Patients were deemed to have had no clinically significant pulmonary embolism at the time of the SPET examination if, within the following 3 months: (1) the patient was alive and had no clinical evidence of pulmonary embolism or, (2) if deceased, pulmonary embolism was unlikely to have been the cause of death. Operating characteristics were based on the methods of Choi and of Simel. SPET interpretation was categorized as follows: high probability, 143 (14%); low probability, 840 (82%); intermediate, 41 (4%) (in contrast to PIOPED, with 39% intermediate interpretations). Pulmonary angiography was performed in only 4% of patients. Adequate follow-up data were available for 97% of patients. To facilitate comparison with PIOPED, either a high-probability or an intermediate-probability or an intermediate-probability study was considered to be a positive test, and either a low-probability or a normal study was considered to be a negative test. The sensitivity was 83% (PIOPED 82%), specificity 92% (PIOPED 52%), positive predictive value 62% (PIOPED 47%) and negative predictive value 97% (PIOPED 85%). The positive and negative predictive values have not been corrected for prevalence, which was approximately twice as high in the PIOPED study. Lung SPET provided accurate diagnostic information in 96% of patients and specificity was greatly improved compared to planar lung imaging reported in PIOPED. The diminished need for angiography greatly reduced the cost of evaluating patients suspected of having pulmonary embolism.

Adolescent↗

PubMed1995

SPECT of the cervical spine in the evaluation of neck pain after trauma.

In a retrospective study, the authors reviewed the use of SPECT in the evaluation of cervical spine abnormalities in 35 patients with persistent neck pain after trauma. Nineteen patients had normal bone SPECT studies, which, in addition to several volunteers, were used to identify tomographic landmarks and determine resolution of individual vertebrae. Sixteen patients had abnormal SPECT results. When compared to final diagnosis, this group included seven (44%) patients with recent fractures, five (31%) patients with traumatic periostitis (periosteal injury resulting from severe strain), and four patients (25%) with mild cervical strain superimposed on degenerative changes. SPECT sensitivity in the detection of recent fractures was 100% with a specificity of 78%. SPECT detected occult fractures in 7 of 35 patients (27%), including 3 patients with normal radiographs and 4 patients with equivocal radiographs. Recent fractures were excluded in six of nine patients (67%) with known fracture identified on cervical spine radiographs and none of the patients with normal SPECTs had CT or MRI evidence of recent fractures. SPECT was useful in 1) the diagnosis of occult fractures or periostitis (periosteal injury) in patients with normal radiographs, 2) characterization of radiographic abnormalities (recent versus healed fractures), 3) identification of active, possible post-traumatic osteoarthritis superimposed on chronic degenerative disease, and 4) eliminating or targeting subsequent imaging modalities, when appropriate. The authors conclude that bone SPECT has a valuable place in the diagnostic evaluation of patients with persistent neck pain after trauma.

Adolescent↗

PubMed1986

The lung as a metabolic organ.

Recently, the lung has received increasing attention as a metabolic organ. In this role, the lung modulates the composition of the arterial blood by several mechanisms: removing active substances from the plasma, releasing substances into the plasma, temporarily holding substances from circulation, and activating or inactivating substances that pass through the lungs. In this report, the procedures proposed by different investigators for in vivo noninvasive assessment of the lung metabolic functions are reviewed. Most procedures are based on an estimation of the clearance of plasma amines by the lung endothelial cells. This clearance is assessed by measuring the lung uptake or the extraction fraction of an intravenously (IV) injected radiolabeled amine. Our own procedure, which assesses the number of free pulmonary endothelial amine receptors, is discussed in detail. In our procedure, the number of receptors was computed using the number of injected molecules of amine and determining the lung extraction fraction of the amine during its first pass through the lungs. In goats, using N-isopropyl-p-iodoamphetamine labeled with 123I as the radiopharmaceutical, the total number of endothelial lung amine receptors was found to be 1.589 X 10(20). The methods for studying the lung metabolic functions, which are discussed in this report can be applied in humans to evaluate either physiological or pathological conditions.

Amines↗

PubMed1986

Single photon emission computed tomography in the diagnosis of pulmonary thromboembolism.

The use of single photon emission computed tomography (SPECT) as the procedure for screening, assessing the size and number of embolized areas, and evaluating the follow-up of patients with pulmonary thromboembolism (PTE) is reviewed. Details of the technique for acquiring and processing perfusion and ventilation lung SPECTs are presented. The tomographic images produced by SPECT allow the application of a less-expensive diagnostic algorithm than that classically used. This is due to the fact that the SPECT images contain more anatomical and physiological information than similar planar images. The signs of PTE in perfusion SPECT and the significance of mismatch, match, and paradoxical mismatch are discussed and illustrated with examples.

Humans↗

PubMed1985

A noninvasive procedure for in vivo assay of a lung amine endothelial receptor.

Lung endothelial N-isopropyl-p-iodoamphetamine (IMP) binding sites were assessed applying principles of competitive binding assay adapted for in vivo measurements obtained by digital imaging. Data were acquired following the method published by Rahimian et al., a modification of the dual indicator dilution technique of Chinard and Crone. Iodine-123 (123I) IMP, the test cellular tracer, and technetium-99m (99mTc) dextran, the reference vascular tracer were imaged during their first pass through the superior vena cava, right heart, lungs, and left heart in West African dwarf goats. The lung fractional extraction of IMP diminished progressively from 0.96 to 0.20 as the amount of IMP in the test tracer boluses was gradually increased from 0.6 to 150 mg. This demonstrated that lung extraction of IMP is by way of a saturable binding system, presumably receptors. The dissociation constant of IMP-lung binding sites reaction was calculated by Scatchard plot and found to be 11.7 mg. The amount of IMP bound at saturation (R), was found to be 30 mg. Assuming that a single molecule of IMP bound a single receptor, the total number of free receptors was computed as the Avogadro's number times R, divided by the IMP molecular weight, and found to be 6.04 X 10(19). Using a computer model, it was determined that the 20 mg per bolus isotherm was the most sensitive for measuring the number of total free receptors (binding sites). This is the first time, to our knowledge, that noninvasive in vivo assessment of receptors in lung has been accomplished. Basically, the method used can be applied in humans and, also, to assess receptors in organs other than the lungs.

Amphetamines↗

PubMed1976