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At least 19 recordsLinked to original sources
PubMed1995

Magnitude and time course of acute hypoxic pulmonary vasoconstriction in man.

Acute hypoxic pulmonary vasoconstriction has an established role in the preservation of ventilation-perfusion balance. To further characterize this homeostatic response in man we have attempted to measure both the time course and magnitude of blood flow diversion from single hypoxic lobes. Lobar hypoxia (mean PO2 38 +/- 1.5(SEM)mmHg, mean PCO2 39.9 +/- 0.9 mmHg) was induced by inflating catheter-tip balloons in left upper lobe bronchi during fibreoptic bronchoscopy under local anaesthesia in 8 normal subjects. An index of lobar blood flow was obtained by acquiring dynamic scintigraphic lung images during a continuous intravenous infusion of the short-lived radioisotope krypton-81m dissolved in 5% glucose solution. In 3 subjects blood flow to the occluded lobes was monitored while the lobes were maintained under hyperoxic conditions (mean PO2 127.8 +/- 31.5 mmHg, mean PCO2 40.2 +/- 1.3 mmHg). Under hypoxic conditions the blood flow to the occluded lobes fell to 53% of baseline after 5 min with a mean time constant of 151 +/- 24.8 sec. Under hyperoxic conditions there was no significant change from baseline blood flow. We conclude that this technique has allowed us to monitor both the dynamic and steady state responses of the pulmonary circulation to lobar hypoxia in man.

Adult↗
PubMed1992

[Diagnosis of respiratory system diseases using radio isotopes].

Common respiratory diagnostic imaging techniques using radioisotopes are ventilation-perfusion, perfusion, aerosol inhalation and tumor scintigraphy. The special features of respiratory imaging diagnostic techniques using radioisotopes are the possibility of early detection of disease and the non-invasiveness of the procedure. Also, no patient effort is required. The kinds of isotopes used are as follows: ventilation-perfusion (133Xe, 13N, 99mTc-pseudogas), perfusion (131I, 99mTc), aerosol inhalation (99mTc), tumor (67Ga, 201Tl). The advantages of these procedures are expected to lead to further developments in respiratory examinations using radio isotopes.

Female↗
PubMed1996

Radiation pneumonitis imaged with indium-111-pentetreotide.

UNLABELLED: Early recognition of radiation pneumonitis enables adequate treatment with a reasonable chance to prevent late sequelae. The feasibility of 111In-pentetreotide in detecting this condition was explored in this study. METHODS: The degree of lung uptake of 111In-pentetreotide, evaluated both visually and quantitatively by irradiated-to-nonirradiated area ratios (INIA ratio) from planar images after 24 hr, was analyzed in relation to the radiation field and compared with ventilation/perfusion (V/Q) images and chest radiographs or CT in 11 patients who had received radiotherapy to the mediastinum or to the internal mammary nodes, 10 of whom were suspected of having clinical radiation pneumonitis. Additional SPECT studies were used to map lung uptake distribution. RESULTS: Indium-111-pentetreotide scans were positive in nine symptomatic patients examined 2-5 mo after radiotherapy; strongly or moderately positive in eight patients, one of whom was receiving steroid therapy without clinical response; and weakly positive in one patient with good steroid response. Indium-111-pentetreotide studies were negative in one asymptomatic patient examined 1 mo after radiotherapy and in one symptomatic patient, with subsequent diagnosis of aspecific viral pneumonitis, examined 4 mo after irradiation. Positive 111In-pentetreotide scans delineated areas of radiation pneumonitis that adequately correlated with areas of decreased ventilation/perfusion and x-ray abnormalities. INIA ratios varied from 1.01 to 2.16 and, in irradiated areas with visible uptake, the lowest value was 1.29. SPECT showed lung uptake in both superficial and deep lying areas in patients with mantle irradiation fields whereas distribution was limited to anterior areas in internal mammary lymph node chain irradiation. CONCLUSION: Indium-111-pentetreotide can detect radiation pneumonitis and may have a role in both the differential diagnosis of patients who have complaints after radiotherapy, and when supported by quantification in the monitoring of response to steroid therapy.

Feasibility Studies↗
PubMed1987

[Regional cerebral blood flow images of single photon emission computed tomography by N-isopropyl-p-[I-123] iodoamphetamine in patients with brain tumor].

Regional cerebral blood flow (r-CBF) was studied by single photon emission computed tomography (SPECT) using N-isopropyl-p-[I-123] iodoamphetamine (IMP) in order to evaluate CBF in patients with brain tumor. Total 27 studies were carried out in 20 patient, including 8 patients with meningioma, 3 with glioblastoma multiforme, 2 with oligoastrocytoma, and 7 with other intracranial tumors. All CBF images by IMP-SPECT were obtained by using a rotating gamma camera with dual heads. In the serial scans, each scan was started at 20 minutes, 2 hours and 6 hours after intravenous injection of I-123 IMP (3 mCi). The all IMP-SPECT images were compared with cerebral angiogram, X-ray CT (plain and/or enhancement), and images of Kr-81 m SPECT and Tc-99 m SPECT. In 5 patients (4 patients with meningioma and 1 with glioblastoma multiforme) this comparative study was performed before and after surgery to evaluate the r-CBF changes surrounding tumor. The abnormal lesion on X-ray-CT was identified as hot area on CBF image by IMP-SPECT in two cases with meningioma, and in 14 cases the lesion showed cold area. Totally 80% of cases showed abnormal findings on CBF images by IMP-SPECT. The cases which showed no abnormal findings on IMP-SPECT images included 1 case with meningioma which located in frontal base, 2 with small intracranial brain tumor which was smaller than 2 cm in diameter, and 1 with pituitary adenoma. On the IMP-SPECT images scanned 2 hours after injection, hot area, which was identified in two cases with meningioma on the images 20 minutes after injection, was changed into cold area.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphetamines↗