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The aim of the present study was to assess ex-vivo function of pathogen-inactivated versus conventional platelet concentrates (PC) in the perioperative setting.A total of 30 patients who underwent cardiac surgery and who postoperatively depended on the transfusion of two platelet concentrates were enrolled into this study. Of the patients 15 received conventional buffy coat PC (conv. PC) and 15 received pathogen-inactivated PC (PI-PC). Age, volume and platelet content of each PC were recorded. Before (T0) and 30 min after PC transfusion (T1), blood samples were taken and platelet function analyses (MEA) and conventional laboratory coagulation analyses were performed. The transfusion-associated increment of platelet concentration (increment) and the corrected count increment (CCI) were assessed at timepoint T1.There were no significant group differences between the groups in MEA analyses or conventional laboratory at T0 or T1. The platelet content per PC was significantly higher in the PI-PC group [3.3 (3.1/3.5)× 10(11) platelets per PI-PC versus 3 (2.9/3)× 10(11) platelets per conv. PC, p0.001]. Platelet increment (42±27×10(9)/l versus 69.4±29×10(9)/l, p=0.013) was significantly lower in the PI-PC group.Whereas ex-vivo analyses of platelet function did not show any group differences at T1, a significantly lower increment was seen in the pilot study after transfusion of PI-PC as compared to conventional PC.

Improvement of the spatial resolution in positron emission tomography (PET) by incorporation of the image-forming characteristics of the scanner into the process of iterative image reconstruction.All measurements were performed at the whole-body PET system ECAT EXACT HR(+) in 3D mode. The acquired 3D sinograms were sorted into 2D sinograms by means of the Fourier rebinning (FORE) algorithm, which allows the usage of 2D algorithms for image reconstruction. The scanner characteristics were described by a spatially variant line-spread function (LSF), which was determined from activated copper-64 line sources. This information was used to model the physical degradation processes in PET measurements during the course of 2D image reconstruction with the iterative OSEM algorithm. To assess the performance of the high-resolution OSEM algorithm, phantom measurements performed at a cylinder phantom, the hotspot Jaszczack phantom, and the 3D Hoffmann brain phantom as well as different patient examinations were analyzed.Scanner characteristics could be described by a Gaussian-shaped LSF with a full-width at half-maximum increasing from 4.8 mm at the center to 5.5 mm at a radial distance of 10.5 cm. Incorporation of the LSF into the iteration formula resulted in a markedly improved resolution of 3.0 and 3.5 mm, respectively. The evaluation of phantom and patient studies showed that the high-resolution OSEM algorithm not only lead to a better contrast resolution in the reconstructed activity distributions but also to an improved accuracy in the quantification of activity concentrations in small structures without leading to an amplification of image noise or even the occurrence of image artifacts.The spatial and contrast resolution of PET scans can markedly be improved by the presented image restauration algorithm, which is of special interest for the examination of both patients with brain disorders and small animals.

Modern volume PET systems offer the possibility to measure without the shadowing effect of interplane septa (2D mode) and thus to detect coincident events between detectors on distant rings (3D mode). It was the aim of the present paper to characterize the count rate behaviour of a latest-generation whole-body PET system in the 2D and 3D mode as well as to discuss the consequences for the radiation hygiene of PET examinations with 2-[F-18]-fluoro-2-deoxyglucose (18-F-FDG).All experiments were performed with the PET system ECAT EXACT HR+. For 2D data acquisition, a collimator of thin tungsten septa was positioned in the field-of-view. The count rate behaviour of the scanner was evaluated in the 2D and 3D mode over a wide range of F-18 activity concentrations following the NEMA protocol. Moreover, PET images of the EEC whole-body phantom with different inserts were acquired in the 2D and 3D mode over a period of 15 min each. For the 3D measurement, the activity concentrations of the F-18 solution were only half of those used for the 2D measurement.For the circular NEMA phantom (phi = 19.4 cm, length = 19.0 cm), we observed an increase of the system sensitivity in the 3D mode by a factor of about 5 with respect to the 2D mode (27.7 vs. 5.7 cps/Bq/ml). The evaluation of the activity distributions of the EEC phantom reconstructed from the 3D data set revealed a superior image quality compared to the corresponding 2D images despite the fact that the activity concentrations were only half as high.By using the 3D data acquisition mode, it is possible to markedly reduce the amount of activity to be applied to the patient and nevertheless to improve image quality. In our experience, it is sufficient to administer an activity of 150-200 MBq for whole-body examinations with F-18-FDG, which results in an effective equivalent dose of 3 or 4 mSv, respectively.

Using the continuous energy spectra of Compton scattered photons we measured the lower energy discriminator level of a positron emission tomograph (PET).In PET scans, coincident photons with an energy between the lower and upper level of the energy discriminator (LLD/ULD) are acquired. Usually, the energy response of a detector is determined by measurements using various radiation sources with different energies. But this method is limited to the availability of the sources with the desired energies. The procedure described in this paper uses the energy spectrum from Compton scattered photons, providing a continuous energy spectrum for the direct measurement of the energy response of the detectors. For our measurements we used an activated Cu-64 point source (phi = 1 mm) which was positioned in an aluminium sphere (phi = 2 cm).The measured LLD values for a whole-body PET-scanner ECAT EXACT HR+ (CTI/Siemens) were systematically lower than the nominal values (327 keV instead of 350 keV) and confirm the results of C. Watson, recently found for line sources.This leads to an increased number of detected low energy photons (mainly scattered photons) and has to be taken into account within the scatter correction.

The spatial resolution of PET scanners can be improved by using smaller detector elements. This approach, however, results in poorer counting statistics of the reconstructed images. Therefore, the aim of this study was to investigate the influence of different acquisition parameters on the signal-to-noise ratio (SNR) and thus to optimize PET image quality.The experiments were performed with the latest-generation whole-body PET system (ECAT Exact HR+, Siemens/CTI) using the standard 2D and 3D data acquisition parameters recommended by the manufacturer. The EEC whole-body phantom with different inserts was used to simulate patient examinations of the thorax. Emission and transmission scans were acquired with varying numbers of events and at different settings of the lower level energy discriminator. The influence of the number of counts on the SNR was parameterized using a simple model function.For count rates frequently encountered in clinical PET studies, the emission scan has a stronger influence on the SNR in the reconstructed image than the transmission scan. The SNR can be improved by using a higher setting of the lower energy level provided that the total number of counts is kept constant. Based on the established model function, the relative duration of the emission scan with respect to the total acquisition time was optimized, yielding a value of about 75% for both the 2D and 3D mode.The presented phenomenological approach can readily be employed to optimize the SNR and thus the quality of PET images acquired at different scanners or with different examination protocols.

In the recent past, several algorithms have been developed in order to transform 3D sinograms acquired at volume PET systems into 2D data sets. These methods offer the possibility to combine the high sensitivity of the 3D measurement with the advantages of iterative 2D image reconstruction. The purpose of our study was the assessment of this approach by using phantom measurements and patient examinations.The experiments were performed at the latest-generation whole-body PET system ECAT EXACT HR+. For 2D data acquisition, a collimator of thin tungsten septa was positioned in the field-of-view. Prior to image reconstruction, the measured 3D data were sorted into 2D sinograms by suing the Fourier rebinning (FORE) algorithm developed by M. Defrise. The standard filtered backprojection (FBP) method and an optimized ML/EM algorithm with overrelaxation for accelerated convergence were employed for image reconstruction. The spatial resolution of both methods as well as the convergence and noise properties of the ML/EM algorithm were studied in phantom measurements. Furthermore, patient data were acquired in the 2D mode as well as in the 3D mode and reconstructed with both techniques.At the same spatial resolution, the ML/EM-reconstructed images showed fewer and less prominent artefacts than the FBP-reconstructed images. The resulting improved detail conspicuously was achieved for the data acquired in the 2D mode as well as in the 3D mode. The best image quality was obtained by iterative 2D reconstruction of 3D data sets which were previously rebinned into 2D sinograms with help of the FORE algorithm. The phantom measurements revealed that 50 iteration steps with the optimized ML/EM algorithm were sufficient to keep the relative quantitation error below 5%.Our measurements show that the image quality in 3D PET can be improved by using iterative reconstruction techniques. The concept of 3D data acquisition and combining the FORE algorithm with 2D ML/EM reconstruction can readily be employed in clinical practice since the computation time is not considerably longer than that in iterative reconstruction of true 2D data.

In planar radionuclide ventriculography (RNV) identification of the site of initial contraction is possibly by the Fourier phase. First clinical experiences will be presented with a new integrated tomographic technique--ISPECT--in noninvasively assessing the site of ectopic or premature ventricular depolarization. In six patients Fourier phases of RNV and ISPECT were performed and compared in five with results from the corresponding electrophysiologic study. It was possible to exactly localize the beginning of mechanical contraction in the two orthogonal planes: during pacemaker stimulation at the apex of the right ventricle, at the lateral border of a large aneurysm during ventricular tachycardia, and at the site of three of five WPW bundles. In the other two bundles the site of first contraction was near the area found during invasive mapping procedure. Thus, this new ISPECT approach together with planar radionuclide imaging may help in noninvasively localizing the site of ectopic and premature depolarization in addition to surface ECG.

The suitability of a 3-dimensional filter in diminishing the statistical noise of left ventricular volume curves without any systematical error in the left ventricular ejection fraction (EF) was investigated. The EF values were compared in 50 studies on 24 patients. There was no significant systematical difference between the EFs before and after filtering. The filter diminishes the statistical uncertainty of the EF by a factor of 0.47. Therefore, the method may possibly be employed in processing the left ventricular volume curves.

First clinical results of patients with diseases of the lungs. The previous experiences on patients with diseases of the lungs reveal that the regional function diagnostics of the lungs may be extended and improved by functional scintigraphic radiospirometry. Because of the determination of regional lung volumes restrictive lung diseases can be differentiated and analysed more exactly than it has been possible before by the examinations of perfusion and ventilation alone. A further advance of the determination of lung volume is that the question of functional operability can be cleared up exactly. In our opinion the routine use of the functional scintigraphic radiospirometry is justified. A contraindication for this kind of examination should only be pregnancy.

Extensive analysis of heart function by scintigraphy yields global parameters of ventricular volumes and their changes during the heart cycle (ejection fraction, enddiastolic and endsystolic volumes, velocity of contraction and relaxation). Additionally, information regarding localized disorders of wall motion may be obtained in a qualitative and quantitative manner by the parameters "phase" and "amplitude". These parameters can be computed from regional time-activity curves by Fourier analysis. The radionuclide ventriculogram at rest is suitable for the detection and follow-up of asynergies caused by acute and chronic infarction. In can also be used as a method of distinguishing between reversible and irreversible asynergy by therapeutical intervention (intervention ventriculography). Abnormalities of regional wall motion which develop during exercise may indicate hemodynamically relevant coronary artery stenoses.

It could be demonstrated by own investigations that ENU-tumors (brain-tumors induced with Ethyl-Nitroso-Urea) are better for clinical questions than the usual transplantation tumors. In this experimental study the temporal and quantitative condition of accumulation of 64Cu-Dimethylglyoxim and 59Fe-Acetyl-Acetone was investigated in rats with ENU-tumors compared with 99mTc-Pertnetate and and 67Ga-Citrate to answer the questions wether 64Cu-Dimethylglyoxim and 59Fe-Acetyl-Acetone are qualified for brain scanning. 64Cu-Dimethylglyoxim and 59Fe-Acetyl-Acetone show like 99mTc-Pertechnetate and 67Ga-Citrate certain affinity to the tumor. At the same time they accumulate in healthy tissues, too. The kinetice of the single radiopharmaceuticals is different. The rates of accumulation of 64Cu-Dimethylglyoxim after 24 hours and of 59Fe-Acetyl Acetone after 4 hours correspond to the rates of accumulation of 99mTc-Pertechnetate after 1 hour. Opposite to this rates of accumulation of 67Ga-Citrate are, because of the high accumulation in the bone, distinctly worse. There are 3 consequences: 1. Brain scintigraphical investigations should not be made with 67Ga-Citrate. 2. Brain scans with 64Cu-Dimethylglyoxim and 59Fe-Acetyl-Acetone will give no better results than scans with 99mTc-Pertechnetate. 3. Further investigations with 64Cu-Dimethylglyoxim and 59Fe-Acetyl-Acetone are not indicated.

Using local time activity curves parameters are calculated which depend on the local wall motion of the heart cavities. These functional parameters allow the determination of the contours of the heart cavities and the assessment of segmental wall motion disorders. The left ventricular ejection fraction has been calculated by enddiastolic and endsystolic counts using a method which takes into account background inhomogeneity.

Radionuclide ventriculography and cineangiography were performed in 62 patients with suspected coronary artery disease. Regional wall motility irregularities could be demonstrated in 97% of those patients who revealed an irregularity in the cineangiogram. Two small scars of the posterior myocardial wall escaped detection. The sensitivity of the radionuclide ventriculography was 97%, the specificity was 80%, 4 patients with normal cineangiography showed small irregularities in the radionuclide ventriculogram. 70 patients with infarction revealed wall motility irregularities in 90%, whereas perfusion defects could be detected by thallium scintigraphy in 66% (young and old infarctions).

Ejection fraction and end-diastolic volume (EDV) are valuable parameters of left ventricular function. They can be measured by radionuclide ventriculography. This study examines EDV in comparison to two other methods. A comparison was made between EDV derived from radionuclide ventriculography (RNV), standard contrast ventriculography and a 'hybrid' method, which calculates EDV from ejection fraction, heart rate and thermodilution cardiac output. Two groups of patients were examined: 54 patients with various cardiac diseases by contrast and radionuclide ventriculography (RNV); and 18 patients with typical angina were examined by RNV at rest and during exercise three times: Control without medication, 20 minutes after 10 mg metoprolol i.v. and again 10 minutes after the second exercise and 10 mg isosorbide dinitrate sublingually. In comparison to contrast ventriculography RNV overestimated EDV by 27%, and in comparison to the hybrid method by 11% with satisfactory linearity. The extent of error increases with decrease of ventricular volume. The assumption that the two short axes of the left ventricle are equally long causes one quarter of total error. Errors caused by the algorithm delineating the borders of the left ventricle cannot be measured. For clinical purposes radionuclide ventricular EDV seems to yield satisfactory results.

The morphology of human ear conch is said to be rather individual, but a perfect person-identification by this mean is not possible. It is demonstrated by photographs-made in a 15 years' interval-that ear conch and auricular area can be typically marked by proceeding age and specific diseases.

By "camera-cinematography" of the heart, we mean an isotope method which permits detailed observation of cardiac mechanics without the use of a catheter. All that is necessary is an intravenous injection of 10 to 15 mCi 99mTc human serum albumen followed after ten minutes by a five to ten minute period of observation with a scintilation camera. At this time the isotope has become distributed in the blood. Variations in the precordial impulses correspond with intra-cardiac changes of blood volume during a cardiac cycle. Analysis of the R-wave provides adequate information of cyclical volume changes in limited portions of the heart. This is achieved by a monitor with a pseudo-3-dimensional display; contraction and relaxation of the myocardium can be shown for any chosen longitudinal or horizontal diameter of the heart. Our programme allows simultaneous presentation of the movement of any point on the myocardium as a time-activity curve. The method is recommended as an addition to chest radiography, heart screening or cardiac kymography before carrying out cardiac catheterisation.

Computer processed dynamic scintigraphy (CPDS) (Funktionsszintigraphie), as developed 15 years ago essentially in the German Cancer Research Center (Institute of Nuclear Medicine), Heidelberg, shows limitations with regard to temporal spatial resolution. Under fixed count rate conditions, temporal resolution can only be improved at the expense of spatial resolution. The adverse implications of this inverse relationship may be overcome by the use of trigger techniques, resulting in an improvement in statistical information. The strict application of principles as developed in CPDS in gated blood pool procedures leads to parametric scans (functional imaging) displaying optimal utilisation of available information and presentation of regional wall motion abnormalities.

The ejection fraction as determined by gated blood pool studies was compared with the ejection fraction as evaluated by the following conventional methods: 1) biplane cineangiography employing the Simpson rule. Correlation was r = 0.805 (n = 25); 2) the same patients using the area-length method (r = 0.88, n = 25); 3) monoplane cineangiography using the method of Greene et al. (5) (r = 0.86, n = 35). In 20 patients the maximal contraction velocity as evaluated by radionuclide ventriculography was compared with the mean systolic ejection rate. The observed correlation was weak (r = 0.62, n = 20); however, it should be noted that the radionuclide method determines the maximum contraction velocity whereas cinceangiography measures an average value over the whole systole.

Quantitative analysis of nuclear cardiology procedures has stimulated tremendous work in the past and will continue to do so in the future. The impact on routine patient care has grown at a slower pace and should be assessed separately for tissue perfusion and for myocardial contraction. The current status will be presented, focusing on patients with coronary heart disease. In the preinfarct period myocardial scintigraphy with thallium-201 and emission computer tomography (ECT) is the preferred method. The procedure for quantitation includes transfer of all data into a standard polar map and comparing the numbers with a normal, gender-matched data base. The result reveals areas of reduced tracer uptake, color-coded according to the level of significance. Interpretation of these colored polar maps might appear simple, but in fact requires a substantial amount of knowledge to avoid overinterpretation of the results. This has led us to a restricted use of this quantitative tool: following an initial step of reading the original data in terms of short and long axes slices of the left myocardium, the polar map is utilized for verification and for suggestions of any additional lesions. This has to be confirmed by a second reading of the slices, and only this last step defines the lesions to be reported. Quantitation used in this dialectic approach avoids inclusion of artefacts, and at the same time is useful experience for trainees. Furthermore, it allows easy presentation during the clinical conference and statistical analysis of groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular function was assessed by means of radionuclide ventriculography in 42 patients with long-standing (13 +/- 5 yrs) insulin-dependent diabetes mellitus and in eleven healthy age matched control subjects. Only diabetics were included in the study without diabetes related cardiac risk factors such as hypertension and CAD in order to evaluate diabetes specific changes of cardiac function. No differences were seen between diabetics and controls concerning heart rate and functional parameters of left ventricle in systole and diastole. The rapid filling period was not prolonged. According to our radionuclide data there is no evidence of diabetes related impairment of ventricular function in young patients with long-standing type-1-diabetes mellitus.

The mucociliary system of the lung was studied in eight normal subjects and ten patients with chronic bronchitis, using sulfur colloids, labelled with 99mTechnetium. By recording the radioactive impulses over the lung with a scintillation camera and analysing the data with a computer, we were able to exclude extrapulmonary artefacts and to select central areas of the tracheobronchial tree. Time activity curves obtained over the central airways were interpreted by means of a model. In bronchitics the disappearance rate of the radioactive particles was found to depend upon the pattern of deposition and the degress of airway obstruction. Because of the good reproducibility in one and the same subject, the effect of drugs, influencing the mucociliary system, can be tested. We used a newly developed vagolytic substance which did not influence the mucociliary system and which reduced little the airway resistance in patients with chronic bronchitis at the administered dose.

The administration of a diagnostic dose of radioiodide, as in the radioiodide uptake test, results in the formation and secretion of radioactive thyroid hormones (endogenous labelling). In this report a method is described by which thyroid hormones are chromatographically isolated from serum, with the simultaneous assessment of the incorporated radioactivity over a period of time. A low-level counter was used to measure the small amounts of activity present. By this method the hormone phases during a radioiodide uptake test may be better evaluated. The present results show a good diagnostic discrimination between euthyroidism and borderline or definite hyperthyroidism (by a factor of 10 and 40, respectively). The influence of factors such as a small intrathyroidal iodide pool need, or course, to be considered. Hence, by taking into account such parameters as the intrathyroidal iodide pool, the hormone clearance etc, a technique for the measurement of thyroid hormone secretion can be developed.

In a prospective study the importance and reliability of blood-pool scanning were checked. 40 patients were investigated. In 36 patients sonographical evidence of one or more hemangiomas was shown. 4 patients with 11 primary or secondary tumors in the liver were taken as control group. All tumors could be verified by histology or CT. Differentiation between hemangiomas and other space-occupying lesions (benign and malignant tumors) was possible with high accuracy. We found a sensitivity of 100% in hemangiomas larger than 4 cm, a sensitivity of 78% in hemangiomas larger than 3 cm and a sensitivity of 69% in hemangiomas larger than 2 cm. Falsely positive results were not observed. In conclusion, blood-pool scanning of the liver is a reliable method in the differential diagnosis of hemangiomas.

Electrocardiograms and radionuclide ventriculograms were obtained at rest and on exercise in 23 patients (20 men and 3 women, mean age 53.4 years) with exercise-dependent myocardial ischaemia after infarction, as well as in 22 persons (17 men and 5 women, mean age 43 years) without clinical, electrocardiographic and biochemical evidence of coronary heart disease. Among the ischaemia patients exercise-dependent loss of motility, as measured by regional ejection fraction and Fourier amplitude, occurred in 95% (50% of controls) in one sector, in 78% (4.5% of controls) in the two sectors with the highest contractility at rest, and in 74% (0% of controls) in three sectors. On exercise, phase shifts occurred in 87% (27% of controls). When combining the exercise-ECG, global ejection fraction as well as regional motility loss in one sector, in the two sectors with the highest contractility at rest and in three sectors, at least two of the five criteria of abnormality were present in 91.3% of the ischaemia patients, compared with at most one criterion in 90.9% of controls. The results indicate the greater diagnostic value of regional than global measures of ventricular function and emphasize the importance of radionuclide ventriculography as an addition to exercise electrocardiography in the pre-invasive diagnosis of coronary heart disease.

Cyclic precordial variations of radiation after i.v. administration of 15 mCi 99mTc-HSA correspond to cyclic volume changes of ventricular volumes of the heart. The "gated blood pool procedure" yields reliable data. Extensive analysis of these data results in subsequent information concerning left ventricular myocardial behaviour: 1. extent of the regional myocardial contraction 2. homogeneity of the contraction 3. regional contraction velocity 4. regional relaxation velocity. Four parametric scans present the distribution of each one of those parameters within the heart. Gated blood pool data have been compared with angiographic data. Reliability of those parameters obtained by extensive analysis of the gated blood pool data could be proven.

Scintigraphic radio-spirometry combines conventional spirometry with the advantages of a functional isotope technique, thereby providing a clinically useful method for the study of pulmonary function. The advantage of the method consist principally in the ability to estimate physiological values separately for the two lungs, and also for selective portions of each lung. The apparatus, method and quantitative evaluation of the results are discussed in detail and the method is critically evaluated. Indications for radiospirometry are given.

Camera-Kinematography is a nearly noninvasive method to investigate regional motion of the myocard, and allows evaluation of the function of the heart. About 20 min after injection of 15-20 mCi of 99mTC-Human-Serum-Albumin, when the tracer is distributed homogenously within the bloodpool, data acquisition starts. Myocardial wall motion is represented in an appropriate quasi three-dimensional form. In this representation scars can be revealed as "silent" (akinetic) regions, aneurysms by asynchronic motion. Time activity curves for arbitrarily chosen regions can be calculated and give an equivalent for regional volume changes. 16 patients with an old infarction have been investigated. In fourteen cases the location and extent of regions with abnormal motion could be evaluated. Only two cases of a small posterior wall infarction did not show deviations from normal contraction pattern.