A statistical investigation of normal regional intra-subject heterogeneity of brain metabolism and perfusion by F-18 FDG and O-15 H2O PET imaging.

Background: The definite evaluation of the regional cerebral heterogeneity using perfusion and metabolism by a single modality of PET imaging has not been well addressed. Thus a statistical analysis of voxel variables from identical brain regions on metabolic and perfusion PET images was carried out to determine characteristics of the regional heterogeneity of F-18 FDG and O-15 H2O cerebral uptake in normal subjects.

Methods: Fourteen normal subjects with normal CT and/or MRI and physical examination including MMSE were scanned by both F-18 FDG and O-15 H2O PET within same day with head-holder and facemask.

PET perfusion and vasodilator function after angioplasty for acute myocardial infarction.

Unlabelled: The aims of this study were to validate invasive coronary Doppler flows against noninvasive PET assessments of myocardial perfusion and to examine the timing and degree of regional coronary vasodilator reserve recovery in patients who are successfully reperfused with primary angioplasty (PTCA) for acute myocardial infarction.

Methods: PTCA was performed in 21 consecutive patients with acute myocardial infarction; the final diameter stenosis was 25% +/- 7%. After restoration of TIMI Grade 3 flow, all patients underwent quantitative coronary angiography and distal Doppler coronary blood flow studies (basal and after adenosine-induced hyperemia) in the infarct and noninfarct vessels.

Development of a three-dimensional computer-generated lung segment overlay chart.

Knowledge of segmental anatomy improves accuracy and precision in interpretation of perfusion lung studies. We report here a computer-oriented method that allows creation of an 'anatomic wire line diagram overlay of pulmonary segments' (AWLDOPS) for use as reference diagrams to more accurately localize segmental lung scan perfusion defects using MedImage Medview software. Superimposition of AWLDOPS and manipulation of the perfusion images is achieved so as to co-register images in size, obliquity and rotation.

Phantom feet on digital radionuclide images and other scary computer tales.

Malfunction of a computer-assisted digital gamma camera is reported. Despite what appeared to be adequate acceptance testing, an error in the system gave rise to switching of images and identification text. A suggestion is made for using a hot marker, which would avoid the potential error of misinterpretation of patient images.

Decrease in thallium-201 image defect size after permanent coronary occlusion.

In the 24 hours after coronary occlusion, some defects on thallium-201 images decrease in size. This study examined the mechanism of the decrease in defect size in dogs with experimental coronary occlusion. The left anterior descending coronary artery was permanently occluded in chronically instrumented awake dogs.

Localization of radiolabeled mouse alloantibody in a sarcoma induced by 3-methylcholanthrene.

The distribution of twice-purified I-125-labeled alloantibody, prepared from the serum of strain DBA/2J mice obtained after immunization with strain C3H/HeJ spleen cells, was studied in immunosuppressed DBA/2J mice bearing either an allogeneic C3H/HeJ MCA sarcoma (i.e., one induced by 3-methylcholanthrene) or a syngeneic MCA sarcoma.

Evaluation of three imaging instruments in dogs with liver hemotomas: concise communication.

Single-gamma emission computerized tomography (ECT) was compared with transmission computerized tomography (TCT) and scintillation-camera imaging (SC) in eight dogs with acute, solitary hematomas in the left liver lobe. The superior performance of TCT was attributed to its inherently better spatial resolution than those of ECT or SC, and to the fact that studies with TCT could be performed during apnea. ECT was more sensitive than SC to small changes in the spatial distribution of radionuclides.

Early redistribution of thallium-201 after temporary ischemia.

To define the time course of redistribution of thallium-201 (201Tl), ischemia was induced in seven pigs by temporary occlusion of the circumflex coronary artery. After 1 1/2 min of occlusion 201Tl and labeled microspheres were injected into the left atrium. Flow was re-established 4 min after occlusion.

Scintigraphic visualization of myocardial infarcts in baboons using thallium-201 and technetium-99m pyrophosphate.

4 baboons with myocardial infarcts were evaluated using thallium-201 for myocardial imaging and 99Tcm pyrophosphate for infarct visualization. Scintiphotographic findings were compared with the size of myocardial infarcts calculated from measurements of the activity of MB isoenzymes of creatine kinase (CK-MB) in serum and in the myocardium at autopsy, as described by Sobel's method. Lack of thallium-201 accumulation was noted in left ventricular infarcts of 3 of the 4 baboons.

Evaluation of early myocardial ischemia with thallium-201 in the pig.

Thallium-201 was found to be a reliable agent for detecting decreased myocardial perfusion in domestic pigs 1-4 hours after acute coronary occlusion. Substantial variation in myocardial-to-liver count ratios and diagnostic quality was observed in serial images performed in 3 normal pigs, although areas of 1-4 hours-old myocardial ischemia produced by acute circumflex coronary artery ligation in 6 pigs could be reliably detected by in vivo 201Ti imaging. After intravenous 201Ti administration, the animals were sacrificed and sections of normal and ischemic myocardium were counted in a scintillation well counter.

Frequency dependence of regional lung clearance of 133Xe in normal men.

We measured the one-half time of 133Xe washout from the whole lung and from 9 horizontal lung regions in 6 normal men during normal breathing and at 50 breaths/min. The diaphragm was located with a contour map prior to the selection of the 9 horizontal regions. Artifacts caused by the tissue solubility of 133Xe were reduced by expressing regional clearance relative to whole lung clearance.

Dual camera studies of pulmonary function with computer processing of data.

Xenon 133 and 2 scintillation cameras arranged to view both anterior and posterior lung fields are being used routinely for evaluation of pulmonary function. Scintiphotograms are obtained from both cameras throughout the course of both perfusion and ventilation portions of the study. In addition, data from both cameras are digitized and stored on line in a dedicated computer for further analysis.