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Biomedical subjects

C M Kirsch

Publications and source records attributed to C M Kirsch.

At least 145 records · Page 8Linked to original sources
PubMed1984

Time course of thyroglobulin autoantibodies in patients with differentiated thyroid carcinoma after radioiodine therapy.

The time course of thyroglobulin (Tg) was monitored in patients with differentiated thyroid carcinoma after ablative therapy (thyroidectomy + 131I-treatment) with particular respect to endogeneous antibodies (Tg-ABs). In 232 patients (196 without Tg-ABs, 36 with Tg-ABs at the time of treatment) a sensitivity of 88% (accuracy, 93%) was found at the first follow up examination. Twelve months later, 11 of the 36 patients did not present Tg-ABs, therefore, the sensitivity increased to 91% (accuracy, 94%) at that time. It is expected that the determination of Tg can also be employed in patients presenting ABs initially.

Autoantibodies↗
PubMed1984

[201Thallium single photon emission computer tomography (SPECT) in the functional evaluation of coronary stenosis changes. Results of a comparison of stress scintigraphic and coronary angiographic findings].

201TI-Single-photon-emission computed tomography (SPECT) was employed in 57 patients immediately after exercise, followed by a redistribution analysis 3 hours later. 44 patients had coronary artery disease as documented by angiography (of these, 27 patients had an earlier myocardial infarction confirmed). 13 patients produced normal angiograms. 201TI-SPECT revealed a sensitivity of 93% and a specificity of 84%. Referring to a subdivision of the left ventricle into anterior and posterior walls, sensitivity in infarcted segments (96%) was significantly (p less than 0.01) higher than in non-infarcted segments (71%). No difference in sensitivities was found comparing anterior and posterior walls. Specificity of segmental analysis was 92%. Evaluation of segmental pattern (positive or negative redistribution) in old infarctions revealed persisting 201TI defects as frequent as the combination of persisting defects with surrounding redistribution. Non-infarcted segments showed sole redistribution in 89% of the cases. Left ventricular 201TI-SPECT improves the anatomical definition of defects in 201TI uptake. It enhances the functional evaluation of changes in regional perfusion subsequent to pathological coronary morphology.

Cineangiography↗
PubMed1984

Dynamic SPECT with Xe-133: regional cerebral blood flow in patients with unilateral cerebrovascular disease: concise communication.

To validate xenon-133 dynamic single photon emission tomography (SPECT) clinically, 74 patients were examined. Strictly unilateral cerebrovascular disease was confirmed in 47 patients by clinical history and by transmission computerized tomography (TCT) and contrast angiography. Twenty-seven were excluded, considered normal. SPECT flow maps were evaluated visually (against TCT) or by automated region of interest (ROI) techniques (12 areas per slice) to measure area flow (AF) (ml/100 g-min) and interhemispherical area flow ratios (AR). These were compared with normal values. Minimum AF in affected hemisphere decreased, and AR-to-normal difference increased, with the severity of the disease. Visually, low-flow areas were detected twice as frequently in SPECT as areas of low density of TCT. In reversible episodes, sensitivity of AF alone ws significantly below the sensitivity of combined evaluation of flow and ratio.

Adult↗
PubMed1984

Thyroglobulin levels to follow-up patients with treated differentiated thyroid carcinoma.

Serum thyroglobulin (hTg) measurements by commercial radioimmunoassay were performed in the follow-up of 118 patients with differentiated thyroid carcinoma undergoing I-131 local and whole-body scans following surgery and I-131 therapy. Patients with positive anti-hTg antibodies (23% of cases) were excluded. In all remaining I-131 accumulating residual, recurrent, or metastatic tumors, hTg levels were elevated (greater than 6.25 ng/ml, minimum detectable value). Twelve patients with neither recurrence nor metastases had elevated hTg levels. Sensitivity and specificity depended on the threshold used for elevate d hTg levels. At an hTg-threshold of 6.25 ng/ml sensitivity has 100%, specificity has 82%. As hTg levels were reported to depend on endogenous TSH stimulation, it is not yet advisable to replace I-131 scans totally by hTg determination. After having determined an hTg "baseline" below detectable values (less than 6.25 ng/ml), we reduced the number of I-131 scans by half. However, elevated hTg levels were an indication for an I-131 scan. Therefore, on the basis of 23% of our patients who had anti-hTg antibodies the need exists to develop a commercial assay which is independent from antibodies.

Adult↗
PubMed1983

Improvement of bone scintigraphy by quantitative evaluation compared with X-ray studies and iliac crest biopsy in malignant disease.

Bone marrow biopsy of the iliac crest was performed on 268 patients (124 males; 144 females). Of these patients 206 had haematological systemic disorders (HSD) or carcinoma and suspected bone involvement, which was confirmed by biopsy on 66 patients. Bone biopsy was performed not longer than 3 weeks after X-ray examination and bone scintigraphy which, combined, had already raised the suspicion of skeletal involvement in 55% of the 66 patients with skeletal involvement diagnosed by biopsy. Additional quantitative evaluation of the bone scans using bone to soft tissue ratios was able to increase the overall accuracy to 67% in that group. Additional quantitative assessment of the scan yielded considerably more effective bone scintigraphy, particularly in cases with visually normal patterns. Available equipment should therefore be used in scintigraphic bone imaging on a routine basis. It was shown that the various methods of examination, i.e. X-ray, biopsy and scintigraphy with both visual and quantitative evaluation provide their own individual values for the final diagnosis. Therefore, if one of the methods shows a negative result, bone involvement is not excluded and the others should be used for confirmation.

Adult↗
PubMed1983

[Single photon emission computed tomography (SPECT). Principles, results, outlook].

Methods, instrumentation, performance data, clinical use and results of SPECT are presented. Since SPECT is yielding functional tomograms, morphological data are not the major concern with this method. Essentially 99mTc labeled radiopharmaceuticals, 201Tl chloride or 133Xe gas are in current use. SPECT may be considered as a supplement to ultrasound in detecting space-occupying lesions of the liver (combined accuracy 95%). Cranial SPECT already allows quantification of regional cerebral blood flow following inhalation of 133Xe gas. The sensitivity of myocardial SPECT with 201Tl (three-dimensional reconstruction) at rest in patients with severe coronary artery disease was higher than 90%. To further develop SPECT as a functionally oriented supplementary method to other radiodiagnostic procedures, further improvements are required as to performance, reconstruction algorithms and radiopharmaceuticals.

Adult↗
PubMed1983

[133Xe-DSPECT (Dynamic Single Photon Emission CT). Results of a new noninvasive method for measuring regional cerebral blood flow (rCBF). Comparison with cranial angiography and transmission CT].

133Xenon-DSPECT provides measurement of regional cerebral blood flow (rCBF in ml/100 g/min) during and after inhalation of 133Xe gas. The result is displayed as a flow map of three transaxial slices. ROI divide a slice into 12 areas (SA) computing flow values (FSA). The results in 36 patients with cranial vascular disease are presented in comparison to 12 "normals". In all patients, FSA in the diseased hemisphere were found to be below the standard range of normals. Related to number of SA, this was true in completed stroke (bilateral) in 55% or (unilateral) in 14%, in PRIND in 5% of SA and in TIA in 7%. The absolute flow values did not decrease with the severeness of the disease, presumably depending on patient's age. There were more (p less than 0,005) SA found with decreased rCBF (21%) than areas with low density in T-CT (10%). Since unilateral cerebrovascular findings presented also bilateral reduced FSA, the validity of the method lies in the calculation of flow values, which significantly adds to the results of imaging.

Cerebral Angiography↗
PubMed1983

Detection of severe cornary heart disease with TI-201: comparison of resting single photon emission tomography with invasive arteriography.

To investigate the application of TI-201 single photon emission computed tomography (SPECT) at rest in the confirmation of coronary heart disease (CHD), we studied 95 patients who had all undergone coronary angiography and cineventriculography. We separated three groups, patients with (a) prior myocardial infarction (MI) (n = 45), (b) no history of MI (n = 40), and (c) no abnormality of coronary angiogram (n = 23). The results of planar imaging with computer-assisted evaluation (scintimetry, SCM) and of SPECT with a three-plane reconstruction (transverse, sagittal, frontal) were compared with the invasive, arteriographic findings. SPECT yielded a higher sensitivity (93%) than SCM (68%) in the detection of defects in both infarcted and noninfarcted groups. The specificity was found to be almost equal in the two imaging modalities. A significant (p less than or equal to 0.01) increase in accuracy was found in SPECT in the assessment of the posterior wall (54% compared with 88%) as well as in the general detection of defects (68% compared with 88%). Applying the SPECT imaging technique increases both the diagnostic accuracy of TI-201 myocardial imaging and the anatomical association of CHD.

Adult↗
PubMed1982

Measurement of infarct size using single photon emission computed tomography and technetium-99m pyrophosphate: a description of the method and comparison with patient prognosis.

The application of dual tracer transaxial emission computed tomography of the heart was studied with use of technetium-99m pyrophosphate and technetium-99m-labeled red blood cells for measuring infarct size in 20 patients with acute myocardial infarction and 10 without infarction. Imaging was performed with a standard gamma camera and with a multidetector transaxial emission computed tomographic body scanner 3 hours after injection of technetium-99m pyrophosphate. Immediately after the scanning procedure, technetium-99m pertechnetate was injected to label red blood cells, and the scanning protocol was repeated. Technetium-99m pyrophosphate was detected in the anterior wall with involvement of the interventricular septum or lateral wall in patients with electrocardiographic criteria for anterior infarction, whereas uptake was detected in the diaphragmatic left ventricular wall with involvement of the posterior, posteroseptal or posterolateral left ventricle or of the right ventricle in patients with electrocardiographic criteria for inferior or posterior infarction. Infarct size measured from transaxial images ranged from 14.0 to 117.0 g in weight. There was a direct relation between infarct size and patient prognosis in that, of the 13 patients with infarct greater than 40 g, 11 (85 percent) had complications, whereas only 2 (29 percent) of 7 patients with an infarct less than 40 g had complications during a follow-up period averaging 17.8 months (p less than 0.05).

Aged↗
PubMed1982

Quantitative multi-detector emission computerized tomography using iterative attenuation compensation.

An iterative procedure to correct for attenuation has been developed for a multidetector, single-photon emission tomographic scanner. The difference between measured and estimated data projections is used at each iteration to form an error image which is used, in turn, to correct the image. A damping factor that minimizes chi2 is applied after each iteration to speed convergence. Several phantoms of different size, with various concentration distributions, have been used to compare this method with a first-order multiplicative attenuation correction used previously with this scanner. The first-order correction is inadequate for most of the phantoms studied, whereas relative and absolute quantitative capability is demonstrated for the iterative attenuation correction. The reconstructed average number of counts per pixel is a linear function of activity concentration up to 5 muCi/ml for all regions of uniform activity whose size is greater than or equal to 5 cm. The importance of using an accurate attenuation distribution with this method is demonstrated with a torso-like phantom.

Mathematics↗
PubMed1981

Characteristics of a scanning, multidetector, single-photon ECT body imager.

We evaluated a single-photon emission computed tomographic system using ten scanning detectors in a circular array. The system uses focusing collimators that scan radially as well as tangentially. The spatial resolution in the tomographic plane is 2.6 cm FWHM and the axial resolution is 3.3 cm FWHM. The resolution is independent of position within the field of view, and nearly independent of energy through 511 keV. Sensitivity was found to be 4600 cps/muCi-ml for an extended phantom, 20-cm in diameter, filled with Tc-99m; 7200 cps/muCi-ml with TI-201; and 8000 cps/muCi-ml with Ga-67. Investigations of positional uniformity indicated some quantitative distortion of data due to inadequate attenuation correction. Improvement in the attenuation correction is necessary before truly quantitative tracer distribution studies are undertaken.

Evaluation Studies as Topic↗
PubMed1980

[The determination of the ejection fraction of the left ventricle by the first passage of an indicator bolus. Comparison of two curve-fitting algorithms (author's transl)].

In 28 studies of the first left ventricular bolus passage, the end-systolic and end-diastolic phase were determined in the left ventricular time activity curve (4 msec per frame) by simply smoothing this curve 25 times. Comparing this method with a highly sophisticated curve-fitting algorithm (Sinusoidial Approximation), a very high correlation (r = 0.95) was found of the resulting ejection fractions. Thus, the two methods can be regarded as equivalent. In comparison with the ejection fractions evaluated by cineventriculoangiographic studies, a good correlation (r = 0.85) was obtained as well. To generate end-systolic and end-diastolic frames the two frames containing the highest left ventricular radioactivity were designated as end-diastolic, and the two frames containing the lowest radioactivity as end-systolic, for each heart cycle. This criterion was found to be very efficient although the temporal resolution was 8 msec per image. Furthermore, mean filling- and ejection-times of the left ventricle were derived from the extensively smoothed time activity curve. Those parameters seemed not to be of great clinical value. By employment of fast computing procedures, the evaluation time of a first passage (including image and curve generation) could be reduced to less than 10 min. Accuracy remained constant so that this method was introduced into our clinical routine diagnostics.

Cardiac Output↗
PubMed1979

[Results of employing single crystal gammacamera and minicomputer in the first tracer passage to determine left-ventricular ejection fraction and wall motion (author's transl)].

Single crystal gammacamera and minicomputer were employed in 71 patients to determine left-ventricular ejection fraction (EF) (17 mCi 99mTc-HSA; 30 degrees RAO projection) by means of the first tracer passage. In 30 out of these patients, ventricular wall motion could be analyzed additionally because later on the gammacamera was equipped with a converging collimator. Comparison with cineventriculographically determined EF values revealed a good correlation (r = 0.91), not depending on left-ventricular wall motion pattern. Hereby, with first transit, high EFs were computed somewhat lower and low EFs were found somewhat higher. This non-limiting discrepancy is closely related to the influence of paracardiac "background"-radioactivity. Comparative analysis of segmental wall motion demonstrated agreement in 83% of the 90 segments examined. Therefore, it can be confirmed that performance of the first tracer passage for a evaluating segmental wall motion must not mandatorily be done with a multicrystal camera.

Adult↗
PubMedDate not supplied

Three-year follow-up on scintigraphically assessed cardiac sympathetic denervation in patients with long-term insulin-dependent (type I) diabetes mellitus.

Scintigraphy using I-123-metaiodobenzylguanidine (I-123-MIBG) and Tc-99m-methoxyisobutylisonitrile (Tc-99m-MIBI) allows assessment of the cardiac sympathetic innervation and the myocardial perfusion. To investigate the natural history of cardiac sympathetic denervation in long-term diabetic patients without myocardial perfusion defects, global and regional I-123-MIBG and Tc-99m-MIBI uptake was determined (score 1-6; 1 = normal uptake, 6 = no uptake) in 22 patients with insulin-dependent (type I) diabetes mellitus (IDDM) at 3-year follow-up. All patients were treated with intensive insulin therapy and HbA1c was 8.0% +/- 1.0% at entry compared with 7.9% +/- 1.1% at follow-up. Cardiac sympathetic denervation (I-123-MIBG uptake score > 2), initially observed in 18 patients, was detectable in 21 patients at follow-up. The global myocardial I-123-MIBG uptake score deteriorated in eight patients, remained unchanged in 11 and improved in three patients. The changes in mean global I-123-MIBG uptake score (3.5 +/- 1.0 versus 3.8 +/- 0.8) were not significant. Reduction of the anterior, lateral, posterior, septal, and apical I-123-MIBG uptake did not progress significantly during follow-up. The mean uptake score of the posterior myocardial region (4.7 +/- 0.8) was smaller than the uptake score of the anterior (3.0 +/- 1.1, p = 0.001), lateral (3.2 +/- 0.9, p < 0.001) and septal (4.1 +/- 1.1, p < 0.05) myocardial regions. At follow-up, moderate myocardial perfusion defects (global Tc-99m-MIBI uptake score = 3) were detectable in four patients. Our study demonstrates that scintigraphically assessed cardiac sympathetic denervation does neither significantly regress nor progress on the average in a group of long-term IDDM patients during a 3-year follow-up. Thus, it is concluded that cardiac sympathetic abnormalities are a persistent, yet frequent phenomenon in long-term IDDM patients.

3-Iodobenzylguanidine↗