Proportional anatomical stereotactic atlas for visual interpretation of brain SPET perfusion images

A semi-automatic method was developed to determine the anterior (AC) and posterior (PC) commissures on brain single-photon emission tomographic (SPET) perfusion images, and then to draw the proportional anatomical Talairach's grid on each axial SPET image. First, the AC-PC line was defined on SPET images from the linear regression of four internal landmarks (frontal pole of the brain, inferior limit of the anterior corpus callosum, sub-thalamic point and occipital pole). Second, the SPET position of AC and PC points on the AC-PC line was automatically determined from measurements made on hard copies of magnetic resonance (MR) images of the patients. Finally, a proportional Talairach's grid was automatically drawn on each axial SPET image. To assess the accuracy of localization of AC and PC points, co-registered technetium-99m hexamethylpropylene amine oxime SPET and MR images from 11 subjects were used. The mean displacements between estimated points on SPET and true points on MRI (x=sagittal, y=frontal and z=axial displacement) were calculated. The mean displacements (in mm) were x=–1.4±1.8, y=–1.7±3.3 and z=–1.1±2.5 for AC, and x=–1.8±1.8, y=0.3±3.2 and =–1.3±2.7 for PC. These displacements represented an error of less than 5 mm at the anterior or posterior pole of the brain or at the vertex. Intra- and inter-observer comparisons did not reveal significant differences in mean displacements. Thus, this semi-automatic method results in reproducible and accurate stereotactic localization of SPET perfusion abnormalities. This method can be used routinely for repeat follow-up studies in the same subject as well as in different individuals without requiring SPET MRI co-registration.     

Quantification of left ventricular size on exercise thallium-201 single-photon emission tomography

The purposes of this study were to determine whether quantification of the left ventricular size on exercise thallium-201 single-photon emission tomography (SPET) correlates with echocardiographic measurements, whether the quantification reflects the severity of coronary artery disease, and whether it can provide supplementary information regarding the severity of coronary artery disease. In 42 control subjects and 110 patients who underwent coronary angiography, we performed exercise²⁰¹Tl SPET and quantified six non-regional markers: lung²⁰¹Tl uptake on an initial planar image (Lung/Heart), left ventricular width on a tomogram (Width), change in the Width from the initial to delayed tomograms (Width), count ratio of the left ventricular cavity to the myocardium (C/M), count ratio of the lung to the myocardium (UM), and count ratio of the lung to the left ventricular cavity (L/C). In 76 patients, furthermore, the Width was compared with echocardiographic measurements. The Width correlated with echocardiographic measurements (P<0.001). The Width and Width were significantly different among zero-, one-, two- and three-vessel disease (P<0.001). However, the Width and Width could not improve the power of discrimination for multi-vessel disease derived from the Lung/Heart. The six non-regional markers correlated with each other (P<0.001). Among the six markers, the Lung/Heart was only the independent discriminator for multi-vessel disease. In conclusion, quantification of the left ventricular size on exercise²⁰¹Tl SPET correlated with echocardiographic measurements and reflected the severity of coronary artery disease, but may be replaced with quantitation of the lung²⁰¹Tl uptake.     

Improvement of brain single photon emission tomography (SPET) using transmission data acquisition in a four-head SPET scanner

Attenuation coefficient maps (-maps) are a useful way to compensate for non-uniform attenuation when performing single photon emission tomography (SPET). A new method was developed to record single photon transmission data and a-map for the brain was produced using a four-head SPET scanner. Transmission data were acquired by a gamma camera opposite to a flood radioactive source attached to one of four gamma cameras in the four-head SPET scanner. Attenuation correction was performed using the iterative expectation maximization algorithm and the-map. Phantom studies demonstrated that this method could reconstruct the distribution of radioactivity more accurately than conventional methods, even for a severely non-uniform-map, and could improve the quality of SPET images. Clinical application to technetium-99m hexamethylpropylene amine oxime (HMPAO) brain SPET also demonstrated the usefulness of this method. Thus, this method appears to be promising for improvement in the image quality and quantitative accuracy of brain SPET.This work was presented in part at the World Congress on Medical Physics and Biomedical Engineering, 7–12 July 1991, Kyoto, Japan     

Can pre-operative contrast-enhanced dynamic MR imaging for prostate cancer predict microvessel density in prostatectomy specimens?

The aim of this study was to correlate quantitative dynamic contrast-enhanced MRI (DCE MRI) parameters with microvessel density (MVD) in prostate carcinoma. Twenty-eight patients with biopsy-proven prostate carcinoma were examined by endorectal MRI including multiplanar T2- and T1-weighted spin-echo and dynamic T1-weighted turbo-FLASH MRI during and after intravenous Gd-DTPA administration. Microvessels were stained on surgical specimens using a CD31 monoclonal antibody. The MVD was quantified in hot spots by counting (MVC) and determining the area fraction by morphometry (MVAF). The DCE MRI data were analyzed using an open pharmacokinetic two-compartment model. In corresponding anatomic locations the time shift (t) between the beginning of signal enhancement of cancer and adjacent normal prostatic tissue, the degree of contrast enhancement and the contrast exchange rate constant (k₂₁) were calculated. The MVC and MVAF were elevated in carcinoma (p<0.001 and p=0.002, respectively) and correlated to k₂₁ (r=0.62, p<0.001 and r=0.80, p<0.001, respectively). k₂₁-values of carcinoma were significantly higher compared with normal peripheral but not central zone tissue. t was longer in high compared with low-grade tumors (p=0.025). The DCE MRI can provide important information about individual MVD in prostate cancer, which may be helpful for guiding biopsy and assessing individual prognosis.     

Morbus Alzheimer - Die Geschichte einer Erkrankung und die Rolle der modernen diagnostischen Radiologie

The effect of the Prandtl number (Pr) and the Reynolds number (Re) on the behaviour of weak laminar axisymmetric and plane fountains has been studied using dimensional and scaling analyses and direct numerical simulation. For Fr 1.0 and assuming viscous effects are important, the analysis shows that for both the axisymmetric and plane fountains, y_mFrRe^–1/2, where Fr is the Froude number defined at the fountain source and y_m is the non-dimensionalized fountain height. These scalings are also valid for the non-dimensionalized fountain width. The analyses also shows _msFr², where _ms is the non-dimensionalized time scale for the fountain flow in the fountain core to reach steady state, and using this time scale y_TFr(RePr)^–1/2, where y_T is the non-dimensionalized thickness of the temperature layer on the symmetry axis over which the fountain fluid temperature changes from the inlet value to that of the ambient fluid. All these scalings have been quantified by the direct numerical simulations, hence confirming in certain ranges the phenomenological scaling obtained in this paper. The financial supports from the National Natural Science Foundation (grant numbers 19872059 and 10262003) and Yunnan Province of the People's Republic of China to W. Lin and the Australian Research Council are gratefully acknowledged.     

Mitteilungen des Berufsverbandes der Deutschen Radiologen (BDR)

The effect of the Prandtl number (Pr) and the Reynolds number (Re) on the behaviour of weak laminar axisymmetric and plane fountains has been studied using dimensional and scaling analyses and direct numerical simulation. For Fr 1.0 and assuming viscous effects are important, the analysis shows that for both the axisymmetric and plane fountains, y_mFrRe^–1/2, where Fr is the Froude number defined at the fountain source and y_m is the non-dimensionalized fountain height. These scalings are also valid for the non-dimensionalized fountain width. The analyses also shows _msFr², where _ms is the non-dimensionalized time scale for the fountain flow in the fountain core to reach steady state, and using this time scale y_TFr(RePr)^–1/2, where y_T is the non-dimensionalized thickness of the temperature layer on the symmetry axis over which the fountain fluid temperature changes from the inlet value to that of the ambient fluid. All these scalings have been quantified by the direct numerical simulations, hence confirming in certain ranges the phenomenological scaling obtained in this paper. The financial supports from the National Natural Science Foundation (grant numbers 19872059 and 10262003) and Yunnan Province of the People's Republic of China to W. Lin and the Australian Research Council are gratefully acknowledged.     

A pragmatic approach to metal artifact reduction in CT: merging of metal artifact reduced images

The purpose of this study was to improve metal artifact reduction (MAR) in X-ray computed tomography (CT) by the combination of two artifact reduction methods. The presented method constitutes an image-based weighted superposition of images processed with two known methods for MAR: linear interpolation of reprojected metal traces (LI) and multi-dimensional adaptive filtering of the raw data (MAF). Two weighting concepts were realized that take into account mean distances of image points from metal objects or additional directional components. Artifact reduction on patient data from the jaw and the hip region shows that although the application of only one of the MAR algorithms can already improve image quality, these methods have specific drawbacks. While MAF does not correct corrupted CT values, LI often introduces secondary artifacts. The corrective impact of the merging algorithm is almost always superior to the application of only one of the methods. The results obtained with directional weighting are equal to or in many cases better than those of the distance weighting scheme. Merging combines the advantages of two fundamentally different approaches to artifact reduction and can improve the quality of images that are affected by metal artifacts.Symbols LI linear interpolation algorithm - MAF multi-dimensional adaptive filtering algorithm - MAR metal artifact reduction - f(x, y) object function at (x, y) - F(), F() normalized filter function in the direction of the coordinates and - I primary X-ray intensity - I₀ transmitted X-ray intensity - N_D number of detectors per detector row - p attenuation - p(,), p(,) projection data (fan and parallel geometry) - p_th lower threshold of the attenuation of adaptive filtering - p_max maximum value of the attenuation of adaptive filtering - (x, y) image point - projection angle in fan geometry - angle within the fan relative to the central ray - , , z, , minimum functions for adaptive filtering - projection angle in parallel geometry - orthogonal distance of a ray to the center of rotation in parallel geometry     

The binding parameters of radiolabelled monoclonal F (ab′)2 and Fab′ fragments relative to immunoglobulin G in reactions with surface-bound antigens

The binding parameters of iodine-125-labelled intact monoclonal immunoglobulin G (IgG), F(ab)₂ and Fab fragments were compared. The study was carried out with the two monoclonal antibodies (MoAbs) K13 and K16 specific for human Ig light chains K and , respectively. When testing the ¹²⁵I-MoAbs against monodisperse polymer particles coated with the specific antigens, the K_a for the F(ab)₂ fragments were similar to that for IgG, while the K_a for the Fab fragments were reduced to 10%–20% of that for IgG. The number N of effective target sites revealed with Fab was higher than with F(ab)₂ and IgG, presumably because less surface area is occupied by the small Fab molecules. The immunoreactive fraction F ranged according to IgG > F(ab)₂ > Fab. The explanation of the moderate difference between the K_a of the monoclonal Fab and the divalent IgG and F(ab)₂ was that the divalent molecules were not divalently attached to the particles. When testing the same antibody preparations against human lymphoma cells producing Ig with light chains K or , the binding results were less reliable than when particles were utilised, presumably due to antigen shedding. Different MoAbs vary in their loss of immunoreactivity due to enzymatic degradation and the radiolabelling procedure. The preparation of the radiolabelled fragments should therefore be optimized for each MoAb, and evaluation is necessary before injection. Artificial targets with a low leakage of antigen, like the monodisperse polymer particles here applied, are recommended for the in vitro evaluation of the immunoreactivity of labelled MoAb preparations.     

A simple method for the quantification of benzodiazepine receptors using iodine-123 iomazenil and single-photon emission tomography

Iodine-123 iomazenil (Iomazenil) is a ligand for central type benzodiazepine receptors that is suitable for single-photon emission tomography (SPET). The purpose of this study was to develop a simple method for the quantification of its binding potential (BP). The method is based on a two-compartment model (K ₁, influx rate constant;k ₂, efflux rate constant;V _T (=K ₁/k ₂), the total distribution volumes relative to the total arterial tracer concentration), and requires two SPET scans and one blood sampling. For a given input function, the radioactivity ratio of the early to delayed scans can be considered to tabulate as a function ofk ₂, and a table lookup procedure provides the correspondingk ₂ value, from whichK ₁ andV _T values are then calculated. The arterial input function is obtained by calibration of the standard input function by the single blood sampling. SPET studies were performed on 14 patients with cerebrovascular diseases, dementia or brain tumours (mean age±SD, 56.0±12.2). None of the patients had any heart, renal or liver disease. A dynamic SPET scan was performed following intravenous bolus injection of Iomazenil. A static SPET scan was performed at 180 min after injection. Frequent blood sampling from the brachial artery was performed on all subjects for determination of the arterial input function. Two-compartment model analysis was validated for calculation of theV _T value of Iomazenil. Good correlations were observed betweenV _T values calculated by three-compartment model analysis and those calculated by the present method, in which the scan time combinations (early scan/delayed scan) used were 15/180 min, 30/180 min or 45/180 min (all combinations:r=0.92), supporting the validity of this method. The present method is simple and applicable for clinical use.     

Positive 131Cesium scanning in parathyroid adenoma

In a case of primary hyperparathyroidism, a palpable nodule, at the base of the right lobe of the thyroid, proved cool during ^99mTc scanning, but hot when scanned with radiocesium. The uptake of this tracer was higher than the uptake of ⁷⁵Se-selenomethionine after suppression with T₃.The authors discuss the possibility of cases of false-positive radiocesium uptake in extrathyroid nodules, and in particular, the use of this tracer for the detection of parathyroid adenoma by scanning.     

Parameters influencing SPET regional brain uptake of technetium-99m hexamethylpropylene amine oxime measured by calibrated point sources as an external standard

Using calibrated point sources as an external standard to convert single-photon emission tomography (SPET) brain counts into absolute values of regional brain uptake (rBU) of technetium-99m hexamethylpropylene amine oxime (HMPAO), the relative contribution of different parameters to interindividual variability of cerebellar rBU was examined in 33 healthy volunteers. Stepwise regression analysis identified body surface as the most important factor underlying interindividual variability (P<0.001), when compared with brain volume. In the normal volunteer population presented, age decrement of rBU corrected for body surface and brain volume equalled 60.5–0.20×age. Based on the data of eight normal volunteers, including four test-retest studies with heart rate (HR) differences greater than 5 units and four test-stress studies with doubling of heart rate after bicycle exercise, influence of heart rate may be expressed by the equation rBU=0.35 HR. Clinically, estimation of the relative influence of different factors allows normalization and extension of the applicability of the rBU quantification method used from longitudinal studies to group comparisons. Interestingly, results of the Daily Stress Inventory Scale and a subjective rating scale suggest the absence of a significant influence of minor stress on rBU. When using one vial per patient, chromatography may be omitted in clinical routine practice and lipophilicity may be estimated as 90% of the injected dose, if administered within 10 min after preparation. Finally, sensitivity of the quantification method was tested in eight volunteers using acetazolamide brain activation and showed a mean increase in cerebellar rBU of 30.2%, varying between 14.1% and 75.9%.     

Measurement of cerebral blood flow in the pig by the 133Xe clearance technique

The ¹³³Xe clearance technique is used to measure cerebral blood flow in the pig. Previous publications have shown that the two-compartmental model is inadequate for interpreting the experimental data. The present study deals with certain phenomena seen during the initial part of the clearance curves, which can lead to incorrect estimation of the blood flow rate.Two types of initial peaks can be distinguished: one is a very fast type, which is interpreted as being due to transit of the tracer via large vessels and is referred to in the literature as the arterial peak; the second is a slower tissue peak, seen in animal experiments at high CO₂ levels and in clinical patients with cerebrovascular instability.In animal preparations discrepancies were found between flow measurements according to the ¹³³Xe clearance technique and those made with the aid of an electromagnetic flow probe situated around the carotid artery. A hysteresis effect was also found in the relation between respired CO₂ level and cerebral blood flow.All these findings can be interpreted in terms of arteriovenous shunting, i.e., non-nutrient flow of blood, which is not necessarily due to anatomical anastomosis but can also be explained by the assumption that the clearance is partly limited by diffusion.The possibility of diffusion-limited clearance can have important clinical implications. Further research may provide a better basis for analysis of clearance curves to detect cerebral perfusion deficiencies that give rise to false flow calculations in present techniques.     

Unexpected differences in early thyroidal trapping of iodide and pertechnetate

Compartmental analysis was applied to simultaneously acquired ¹³²I-iodide and ^99mTc-pertechnetate thyroid uptake data. The method allowed for arterio/venous differences in plasma tracer level and for an instantaneous phase of thyroid uptake.Observations in four thyrotoxic patients, before and during antithyroid drug therapy, revealed greater instantaneous uptake of TcO ₄ ^- . The results also revealed that instantaneous uptake of both I^– and TcO ₄ ^– may increase over the first six months of drug therapy. These findings could not be explained by the estimates of unidirectional clearance which were greater for I^- and varied little during the early stages of drug therapy.     

Morbus Alzheimer - Die Geschichte einer Erkrankung und die Rolle der modernen diagnostischen Radiologie

The effect of the Prandtl number (Pr) and the Reynolds number (Re) on the behaviour of weak laminar axisymmetric and plane fountains has been studied using dimensional and scaling analyses and direct numerical simulation. For Fr 1.0 and assuming viscous effects are important, the analysis shows that for both the axisymmetric and plane fountains, y_mFrRe^–1/2, where Fr is the Froude number defined at the fountain source and y_m is the non-dimensionalized fountain height. These scalings are also valid for the non-dimensionalized fountain width. The analyses also shows _msFr², where _ms is the non-dimensionalized time scale for the fountain flow in the fountain core to reach steady state, and using this time scale y_TFr(RePr)^–1/2, where y_T is the non-dimensionalized thickness of the temperature layer on the symmetry axis over which the fountain fluid temperature changes from the inlet value to that of the ambient fluid. All these scalings have been quantified by the direct numerical simulations, hence confirming in certain ranges the phenomenological scaling obtained in this paper.     

Gated cardiac blood pool studies in atrial fibrillation: role of cycle length windowing

Cycle length windowing is gaining increasing acceptance in gated blood pool imaging of patients with atrial fibrillation (AF). The goals of this study were: to assess differences of ejection fraction (EF) in AF with and without windowing and to determine how EF varied with cycle length in patients with AF. Twenty patients with AF were prospectively studied by gated blood pool imaging, with simultaneous collection in each patient of 5–7 studies with cycle length windows spanning the cycle length histogram. Each window accepted beats of only a narrow range of cycle lengths. EF was determined for each of the narrow cycle length windows as well as for the entire gated blood pool study without cycle length windowing. For every patient an average of the windowed EFs was compared with the non-windowed EF. EF values were similar (mean windowed: 46.6; non-windowed: 45.5; P=0.16), and there was a good correlation between the two techniques (r=0.97). The data were then examined for a relationship of EF with cycle length. The difference from average windowed EF (EF) was calculated for each window and plotted vs. the cycle length of the center of each window. No predictable linear or nonlinear relationship of EF with window position was observed. Lack of predictable variation of EF with cycle length is likely due to lack of a predictable amount of ventricular filling for a given cycle length, as the amount of diastolic filling in AF depends on the random cycle length of the preceding beat. In summary, windowing in AF does not provide a clinically significant difference in EF determination. If cycle length windowing is used, the exact location of the window is not critical.     

Quantification of left ventricular volume in gated equilibrium radioventriculography

We have developed a simple method for measuring left ventricular volume based on semi-automated analysis of 40° left anterior oblique images obtained with a standard scintillation camera after equilibrium of an intravenous injection of 20 mCi of technetium-99m in vivo labeled red blood cells. The essence of the method is the use of the dimensions and radioactivity within a segment of aorta to convert observed left ventricular count rates to volume. Four assumptions were made: 1) the aortic arch is nearly parallel to the collimator face when a patient is in the proper left anterior oblique position; 2) a segment at the top of the aortic arch, approximately 1 cm wide, is a right cylinder, 3) the edges of the aorta can be delineated as the lines where the second derivative of a cross sectional profile equals zero; 4) left ventricular and aortic arch counts undergo the same attenuation because they are nearly the same distance from the chest wall in the proper left anterior oblique position. By measuring the counts and volumes of two regions of known shape, one in the middle, the other at the edge of the aortic arch, and calculating their differences a background-independent volume count ratio (v/C) can be obtained. The left ventricular and diastolic volume (LVEDV) is calculated with the equation: LVEDV=(/C) LVEDC, where LVEDC represents left ventricular end diastolic counts. Twenty-six patients were evaluated by equilibrium radio- and contrast-ventriculography, the latter analyzed by planimetry. The radionuclide method yielded an end diastolic volume that correlated well with contrast ventriculography (r=0.96, Y=0.91 X+21 ml). In addition to its simplicity and objectivity, a major advantage of this method of determining ventricular volume is that it does not require a blood sample.This work was supported in part by USPHS Grant Nos. HL 20674 and GM 10548     

Prognostic value of single-photon emission tomography in acute ischaemic stroke

Single-photon emission tomography (SPET) is widely used in the investigation of acute stroke. We investigated the relationship between SPET data and functional outcome in a large group of acute stroke patients. One hundred and eight patients underwent cerebral computed tomography (CT) and technetium-99m hexamethylpropylene amine oxime SPET after acute ischaemic stroke. We categorised the clinical presentation according to the Oxford classification of acute stroke. Outcome was measured 1 year after stroke using mortality and the Barthel Index for survivors. SPET scans were interpreted without reference to the clinical data using a semi-automatic technique. Three experienced observers determined the presence of luxury perfusion using suitably scaled SPET images in conjunction with the CT scan. Both SPET volume and severity of deficit were significantly negatively correlated with Barthel Index at 1 year (r _s=–0.310,P<0.0001, andr _s=–0.316,P<0.0001 respectively). In patients scanned with SPET within 16 h of stroke onset, the correlations were more strongly negative (r _s=–0.606,P<0.0001, andr _s=–0.492,P<0.005 respectively). Luxury perfusion was not associated ( ²=0.073,df=1,P=0.79) with good functional outcome (Barthel score 60). Stepwise logistic regression identified Oxford classification, total deficit volume and patient's age as significant predictors of functional outcome. Overall predictive accuracy was 72%. Predictive accuracy was better in patients who received SPET within 16 h of stroke onset. SPET provides useful information about the functional outcome of acute stroke at 1 year. However, the accuracy of prediction decreases the longer SPET is delayed. Prognostication using SPET in combination with clinical assessment and other investigations may also be considered.     

Todeszeitbestimmung auf der Basis simultaner Messung von Hirn- und Rektaltemperatur

Zusammenfassung Die Analyse der Daten an 21 Leichen simultan registrierter Hirn- und Rektaltemperaturkurven ergab hinsichtlich separater oder kombinierter Todeszeitberechnungen folgende Ergebnisse und Schlußfolgerungen:Im Bereich einer normierten Hirntemperatur (Q _H) 0,5Q _H<1,0 (etwa bis 6,5 hpm) führt die alleinige Verwendung der Hirntemperatur zu den präzisesten Todeszeitrückrechnungen (Standardabweichung um dt=0 s ₀=±0,75; Variationsbreite 3,3 h). Im Bereich 0,3Q _H<0,5 (etwa 6,5–10,5 hpm) ist die kombinierte Todeszeitrückrechnung mit Wichtung im Verhältnis 6 (Hirn):4 (Rektum) vergleichsweise am präzisesten (s ₀=±1,18; Variationsbreite 5 h). Im Bereich 0,07Q _H<0,3 (jenseits 10,5 hpm) ergibt die alleinige Verwendung der Rektaltemperatur die präzisesten Todeszeitberechnungen (s ₀=±1,62; Variationsbreite 6,6 h).Ein integrierter Rechenansatz aus beiden Rückrechnungsformeln mit dadurch möglicher Elimination der Temperatur bei Todeseintritt scheint im Bereich um 0,7Q _H<1,0 geeignet zu sein, größere Fehler berechneter Todeszeiten in Fällen mit z.B Fieber bei Todeseintritt zu vermeiden (s ₀=±0,69; Variationsbreite 2,7 h).Herrn Prof. Dr. W. Janssen zum 60 Geburtstag gewidmet     

Genetic polymorphism of desialyzed alpha2 HS-glycoprotein by ultrathin isoelectric focusing

Summary The genetically determined polymorphism of ₂ HS-glycoprotein was analyzed by immunoblotting ultrathin-layer polyacrylamide gel isoelectric focusing in the pH range 4–6.5 and neuraminidase pretreated sera. In a Libyan population sample from Tripoli (n=110) three common phenotypes, ₂ HSG 1–1, 2–1, and 2–2, were observed. The allele frequencies were ₂ HSG¹=0.8364 and ₂ HSG²=0.1636. The theoretical exclusion rate in cases of disputed paternity is 11.8%.     

Untersuchungen zum dünnschichtchromatographischen Nachweis eines neuartigen Tranquilizers aus der Trioxazin-Reihe (Versuchspräparat Nr. 518 der Firma Knoll AG.)

Summary The tranquilizer-substance Trioxazine is described and investigations were made for detecting the substance and its metabolites in the urine after intake. It was found, that the unchanged tranquilizer as well as 3 metabolites were excreted. The substance could easily be extracted out of urine with chloroforme after acidifying with hydro-chloric acid. The extract was separated on silica-gel GF₂₅₄-thinlayer-plate in the solvent CHCl₃-n-Heptan-Ethanol (111). For the detection of the substances on the plate it was found, that spraying them with a modified reagent ofSonnenschein, consisting of Cer(IV)sulphate, trichloraceticacid and conc. sulfuric. acid give red spots. An amount of 5 g of Trioxazine can thus be detected. Trioxazine also reacts with conc. nitric acid to a deep red colour.

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Vorgetragen auf der Tagung der Deutschen Gesellschaft für Gerichtliche und Soziale Medizin in Freiburg i. Br. im Oktober 1966.