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H Luig

Publications and source records attributed to H Luig.

At least 37 records · Page 2Linked to original sources
PubMed1985

Improved quality and information in thyroid scintigraphy.

We compared rectilinear scanning, analogous gamma-camera imaging and imaging using a gamma camera interfaced to a computer in order to determine which of these techniques is superior for thyroid scintigraphy. Forty patients with and without goitre and irregular activity distribution were imaged using each of the three techniques. The sets of three scintigrams per patient were rated by seven physicians. These ratings were statistically analysed using a new distribution-free test. Thyroid scintigraphy using a gamma camera interfaced to a computer turned out to be the best method, especially for detecting circumscribed areas of increased uptake. We conclude that this was due to a combination of the following factors: a computer matrix of 128 X 128 pixels in combination with an acquisition zoom of 1.5, the high count density of the scintigrams, computer-controlled documentation after data acquisition and the use of a continuous grey scale for documentation. The improved quality and information content of the scintigrams obtained using a gamma-camera/computer system could improve the diagnostic value of thyroid scintigraphy, especially when the scintigrams are also evaluated quantitatively.

Humans↗
PubMed1985

Spontaneous hemodynamic improvement or stabilization and associated biopsy findings in patients with congestive cardiomyopathy.

The hemodynamic courses of 56 patients with congestive cardiomyopathy (CCM) were investigated. Fourteen patients died within 24 months after diagnosis. The hemodynamic courses of the remaining 42 patients were investigated in subsequent examinations by determination of left ventricular ejection fraction (LVEF), mean pulmonary arterial pressure at maximal workload, and peak systolic pressure/end-systolic volume index. During the study interval of 32.2 +/- 20.0 months the conditions of 20 patients (48%) deteriorated, according to their hemodynamic status, and at least five of these died of terminal heart failure. Surprisingly, the conditions of 22 patients (52%) improved or stabilized. One of these died of leukemia. Seven patients in the latter group with initial LVEFs of 0.30 or less experienced an average increase from 0.22 to 0.51. Retrospectively consideration of age, alcohol intake, exercise capacity, and hemodynamic status were not helpful in predicting the course of the disease. In 38 patients endomyocardial biopsy samples could be obtained at the time of diagnosis. Reduced myofibril volume fraction (less than 60%) had prognostic significance for both hemodynamic deterioration and death (sensitivity 23/24 = 96%), while 14 of 15 patients whose conditions improved or stabilized had a myofibril volume fraction of 60% or more (specificity 14/15 or 93%, p less than .002). A relationship between hemodynamic status and the myofibril volume fraction could not be found. Individual patients with CCM differ significantly with respect to course of the disease. A distinct separation of the patients by means of morphologic criteria is possible. This makes it more likely that the pathogenesis of the disease is not unique.

Adolescent↗
PubMed1984

The preoperative and postoperative findings in 627 patients with tetralogy of Fallot.

The preoperative and postoperative findings in 627 patients operated for correction of tetralogy of Fallot (TOF) in the period 1960 to 1984 were analyzed in order to evaluate the clinical and hemodynamic late results. The average age was 7.2 years (range 9 months to 30 years). The patients were divided into 4 groups in order to determine the long-term prognosis in relation to the severity of the underlying anatomy; group I = without outflow tract patch; group II = with a patch up to the valve base; group III = with a transannular patch (TAP); group IV = TAP or valved conduit in patients with pulmonary atresia. Preceding shunt operations had been performed in 350 patients (55.8%); a primary correction was carried out in 277 cases (44.1%). Hospital mortality for all patients operated from 1960 to 1984 was 14.0%, late mortality, by contrast, was only 1.1%. In the last 4 years (1980 to 1983), the overall mortality considerably decreased to 3.4% (n = 29) for patients without TAP and to 8.0% for all operated patients including those with pulmonary atresia (n = 50). A comparison of the actuarial survival curves, moreover, demonstrates that the prognostic survival rate is unequivocally dependent on the severity of the anatomy of a TOF. The hemodynamic results obtained from 271 recatheterized patients from all 4 groups were designated excellent in 106 patients (39.1%), good in 100 (39.9%) and poor in 65 (23.9%). Proximal residual gradients across the right ventricular outflow tract (RVOT) were found in 30.2% of the corrected patients, and distal gradients in 24.3%. Fifty-two patients out of the 627 (8.2%) had to be reoperated for residual VSD, RVOT aneurysm, valvular pulmonary stenosis or peripheral stenosis. Intracardial electrophysiological tests carried out in 166 patients postoperatively showed an antegrade effective refractory period of the AV-node lasting over 400 ms in 47 patients (28.3%), as well as additional ventricular action potentials in 117 patients (70.4%), which could be correlated to extrasystoles or ventricular tachycardia in 37.9% of the cases. Additional AV-pathways were disclosed in 3 patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

[A nuclear medicine method for determining left ventricular stroke volume].

A new non-invasive nuclear medicine procedure for determining the left ventricular stroke volume is described. The procedure exhibits the following features: 1. Individual calibration of scintigraphic counts in activity by first-pass evaluation; 2. no need for a delta-shaped bolus injection; and 3. determination of different stroke volumes, e.g. during different grades of exercise, by only one injection and by only one blood sample. 36 results obtained at rest and during exercise are compared with corresponding results of the thermodilution method (r = 0.86).

Cardiac Output↗
PubMed1980

[Reno-cardiac interactions in kidney failure (author's transl)].

The high incidence of cardiac complications in endstage renal failure is not only related to the chronic pressure load of the left ventricle, although the proportion of patients with elevated blood pressure increases from 53 to 81% as reno-parenchymal disease progresses. Other factors as anemia, hyperparathyroidism, autonomic neuropathy and retention of electrolytes, metabolic products of toxins may cause damage to the heart. It is a matter of discussion whether uremia itself causes cardiomyopathy. Findings of a reduced Ca++-uptake during beta-adrenergic stimulation and a reduced reaction of (Na+, K+)-ATPase to digitalis suggest a basic change of myocardial membrane metabolism. Retention of an "endogenous digitalis" could help to explain some contradictory results.

Adolescent↗
PubMed1980

[An adaptation function for describing time-activity curves in nuclear medicine (author's transl)].

Radioisotopic time-activity curves can be described by a function known from the physics of heat conduction. This function, called in this paper "tracer function", is a special solution of one-dimensional differential equation of heat conduction. The function is especially useful in the quantitation of left-to-right cardiac shunts by analysis of the pulmonary time-activity curve. The first transit curve is determined from the amplitudes on the ascending slope of the curve only including the maximum. The shunt curve analysis uses two parameters derived from the first transit curve and then the position and amplitude of the shunt curve maximum only.

Hot Temperature↗
PubMed1979

[Typical presentation of sequential scintigraphy images in the diagnosis of cyanotic heart disease in the newborn, using a computer-assisted imaging technique (author's transl)].

The technique of sequential scintigraphy in investigating newborn infants in order to exclude or detect cyanotic congenital heart disease has been improved. The primary scintigraphic data are recorded digitally (list mode, 1 ms, 128 by 128 pixels) and evaluated automatically as a sequence of 1/2 s frames in 1/8 s increments. A 35 mm film is exposed to a scanning pulsed light spot on a CRT-screen with quantitative correspondence between local count density and the local number of light pulses. A series of highly resolved images of the rapidly changing scintigraphic pattern is achieved in 30 min. The results of 3 investigations are discussed. They prove the importance of adequate spatial resolution and definition in time in nuclear angiocardiography in infancy. Three case results are discussed in detail. In one case cardiac catheterisation and angiocardiography had been omitted, since the radioisotopic findings excluded cyanotic congenital heart disease. Two further investigations are discussed with reference to the findings at cardiac catheterisation.

Angiocardiography↗
PubMed1979

[The determination of the left ventrical volume curve without background correction and its validation by direct intercomparison with the ejection fractions as determined by biplane laevocardiography (author's transl)].

Background corrections applied on the left ventricular volume curve determined by the "gated blood pool"--method are based on an estimated rather than on a directly measured background. This imposes an uncertainty on the values determined from the volume curve, especially on the ejection fraction. A method which does not require background correction may be applied if all available measurement and evaluation facilities are utilized fully. High temporal and spatial resolution is of fundamental importance, permitting the exact determination of the time-dependent scintigraphic contour variations of the left ventricle during the mechanical action of the heart. A good criterion of the validity of the volume curves with respect to interfering background radiation is the ejection fraction calculated from these curves. The direct intercomparison of 10 ejection fractions obtained by an expanded "gated blood pool"-method, employing cardiac catheterization, immediately before a biplane laevocardiography demonstrated very good agreement. A small systematic underestimation of the ejection fraction by the nuclear method was observed. This understimulation shows that the influence of the true background is small if other interfering count rate contributions or methodical uncertainties are excluded systematically.

Angiography↗
PubMed1979

[Quantitative exercise scintigraphy of the myocardium with 201Tl--methods and normal values (author's transl)].

Quantitative myocardial scintigraphy was performed in 20 normal individuals after maximum exercise and after two hours of rest. A mobile Anger camera with converging collimator and a Data-General computer with a 128 x 128 matrix were used. Quantitative analysis of data was performed on the basis of a 14-halfsegment model. Quantitative normal values after exercise and after redistribution of activity during rest are presented.

Adult↗
PubMed1977

Quantitative nuclear angiocardiography in valvular heart disease.

A noninvasive method of quantitative nuclear angiocardiography was developed using a camera system and a computer. The investigation, which can be performed on an out-patient basis within 10-15 min, includes the following steps: injection of 10 mCi 99mTc-labelled human serum albumin into a femoral vein, and external recording of the passage of the bolus through the central circulation by a sequence of scintigraphic frames taken during diastole. From time--activity curves over the right ventricle, the pulmonary artery and the left ventricle, peak-to-peak times and mean circulation times were calculated. The method was applied to 424 patients with valvular heart disease proven by heart catherization. The following results were obtained: (1) The method proved to be highly sensitive in stating whether there was a hemodynamically significant valvular disease or not. But differential diagnosis concerning the different forms of valvular disease was not possible. (2) The prolongation of the circulation times correlated with the hemodynamic severity of the disease. (3) The circulation times were directly related to the cardiac index, the enddiastolic volume of the left ventricle and the pressures in the pulmonary vascular system. (4) The method could be used to evaluate the effect of surgery and for follow-up after operation. Quantitative nuclear cardiography may help to fill the gap between the nonquantitative, rather unspecific and the specific but invasive methods of cardiologic investigation.

Adolescent↗
PubMed1976

[The effect of biological factors during functional scintigraphy of the heart (author's transl)].

The parameters relating to functional scintigraphy of the heart (average circulation time, peak time) depend not only on the method (injection technique, radiopharmaceutical), but also on biological factors. Failure to take these into consideration may result in an erroneous interpretation of the findings. Circulation time in normal children aged 6 to 14 years, as determined by isotope methods is significantly shorter than in normal adults. Patients with compensated heart disease, as well trained athletes, show significantly shorter than in normal adults. Patients with compensated heart disease, as well trained athletes, show significant increase in all portions of the circulation time, when compared with normals of similar ages. This indicates that deviation in the haemodynamics of the circulation as shown by functional scintigraphy, can only be interpreted in the light of clinical findings.

Adolescent↗