Scintigraphic evidence of the "no reflow" phenomenon in human beings after coronary thrombolysis.

To assess whether the absence of new thallium-201 uptake after successful intracoronary thrombolysis reflects a disturbance of myocardial cell function or lack of capillary reperfusion, dual isotope scintigraphic studies with thallium-201 and technetium-99m micro-albumin aggregates were performed in 16 patients with acute anterior myocardial infarction. Intracoronary thallium-201 and technetium-99m scintigraphy performed before intracoronary thrombolysis in 12 of the 16 patients resulted in identical thallium-201 and technetium-99m defect sizes. Immediately after intracoronary thrombolysis, thallium-201 and technetium-99m scintigraphy was repeated in 11 of the 12 patients. In 4 of the 11, the initial thallium and technetium scintigraphic defects were significantly reduced, and in 6 of the 11, they were only slightly reduced; there was no difference in the size of the residual defect as assessed with both radionuclides in all 10 of the 11 patients. In the eleventh patient, there was a significant reduction of the initial technetium-99m scintigraphic defect but no change in the size of the thallium-201 defect. In four other patients, scintigrams were obtained only after intracoronary thrombolysis; these revealed no difference in thallium-201 and technetium-99m defect size. In seven of eight patients restudied 2 to 4 weeks after intracoronary thrombolysis, thallium-201 and technetium-99m defect sizes were identical with those immediately after intracoronary thrombolysis; in the eighth patient there was no difference in thallium-201 and technetium-99m defect size, although such a difference had been present immediately after intracoronary thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical use of ultrashort-lived radionuclide krypton-81m for noninvasive analysis of right ventricular performance in normal subjects and patients with right ventricular dysfunction.

The ultrashort-lived radionuclide krypton-81m, eluted in 5% dextrose from a bedside rubidium-81m generator, was intravenously infused for rapid imaging of the right-sided heart chambers in the right anterior oblique projection adjusted for optimal right atrioventricular separation. Left-sided heart and lung background was minimized by rapid decay and efficient exhalation of krypton-81m, requiring no algorithm for background correction. A double region of interest method decreased the variability in the assessment of ejection fraction to 5%. In 10 normal subjects, 11 patients with pulmonary hypertension, 4 patients with right ventricular outflow tract obstruction and 4 patients with right ventricular infarction, right ventricular ejection fraction determined by krypton-81m equilibrium blood pool imaging ranged from 14 to 76%. The correlation between these values and those determined by cineangiography according to Simpson's rule was close: r = 0.93 for all data points (p less than 0.001), r = 0.92 for studies at rest (p less than 0.001) and r = 0.93 for exercise studies (p less than 0.001). Exercise-related changes in right ventricular function revealed a disturbed functional reserve with pulmonary hypertension and right ventricular infarction, whereas in compensated right ventricular outflow tract obstruction there was a physiologic increase in ejection fraction with exercise (p less than 0.001). Thus, equilibrium-gated right ventricular imaging using ultrashort-lived krypton-81m is a simple, accurate and reproducible method with potential for serial assessment of right ventricular ejection fraction in a variety of right ventricular anatomic and functional abnormalities, both at rest and during exercise. Advantages of this method include an extremely low radiation dose to patients and clear right atrioventricular separation without the need to correct for background activity.

[Impact of positron emission tomography with FDG-PET in treatment of patients with suspected recurrent ovarian cancer]. / Impacto de la tomografía por emisión de positrones mediante 18-Fluoro-2-Desoxi-D-Glucosa (PET-FDG) en el manejo terapéutico de pacientes con recurrencia secundaria a cáncer de ovario.

AIM: Recurrent ovarian cancer is a major problem and an accurate diagnosis can often change patients' management. This study aimed to assess the impact on management of FDG-PET in recurrent ovarian cancer. MATERIAL AND METHODS: Forty-three patients in whom FDG-PET scan was performed due to suspected recurrent ovarian cancer were included. FDG-PET results were confirmed by histopathology and clinical follow-up of at least 12 months. To assess impact on management the treatment plan based on conventional imaging methods was compared with the treatment plan based on inclusion of PET findings, classifying FDG-PET impact on management as high, medium, low or no impact. Management changes, when present, were classified as intermodality or intramodality. RESULTS: FDG-PET had a high impact on therapeutic management in 28 patients (65.1 %), medium impact in 2 patients (4.6 %), low impact in 9 patients (20.9 %), and no impact in 4 patients (9.3 %). FDG-PET induced an intermodality change in management in 27 patients (62,8 %); intramodality changes were induced in 3 patients (7 %). Finally, it produced no treatment changes in 13 patients (30.2 %). CONCLUSION: FDG-PET supplied additional information when compared to conventional diagnostic procedures and allowed adequate management changes in most patients.

Tomographic myocardial perfusion scintigraphy in children with Kawasaki disease.

Myocardial infarction and stenotic coronary lesions are serious late complications in children with Kawasaki disease. For the noninvasive assessment of myocardial perfusion, dipyridamole-redistribution 201Tl emission computed tomography (ECT) was performed in seven children (age 2 8/12-8 7/12 yr) 3-20 mo after the acute stage of the disease. In all patients, coronary aneurysms had been demonstrated by cross-sectional echocardiography. The scintigrams of six children showed no significant regional reduction of myocardial thallium uptake. These children had remained asymptomatic since the acute stage of Kawasaki disease. Persistent and transient thallium defects were present in one child with documented myocardial infarction. For this patient, obstruction of corresponding coronary vessels was confirmed by contrast angiography. It is suggested, that 201Tl ECT after dipyridamole-induced vasodilation may be used as a safe alternative to invasive coronary angiography for follow-up investigations in patients with Kawasaki disease.

Drug therapy and cerebral perfusion in obsessive-compulsive disorder.

Cerebral perfusion in a previously untreated patient with obsessive-compulsive disorder was studied qualitatively and semi-quantitatively with SPECT before, and during and 6 wk after treatment with clomipramine. The patient's symptoms disappeared while on medication and relapsed after drug withdrawal. At baseline, there was an increased perfusion ratio in the bilateral orbitofrontal, anterior cingular, frontotemporal and right caudate regions. These alterations disappeared during drug therapy. After treatment discontinuation and symptomatic relapse, the same pattern of hyperactivity was found. Semiquantitative measurements after treatment withdrawal showed a return to perfusion values similar to those observed before treatment in subcortical structures. In cortical areas, this level was not completely achieved. Subtraction SPECT images showed perfusion changes at the orbitofrontal, caudate and thalamic levels.

Detection of human collateral circulation by vasodilation-thallium-201 tomography.

Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making.

Intracoronary thallium 201 scintigraphy as an immediate predictor of salvaged myocardium following intracoronary lysis.

Since February of 1980, 157 patients who had had symptoms of acute myocardial infarction for less than 3 hours underwent intracoronary lysis. Forty-six patients required early aorta-coronary revascularization. However, operation was believed to be indicated only when intracoronary lysis was successful and myocardium was salvaged. Since left ventricular angiography proved unreliable in assessing the viability of the myocardium in the acute stage, starting in March of 1981 we obtained intracoronary thallium 201 scintiscans in 23 patients before and after intracoronary lysis. Patients in whom there was a significant reduction (greater than 50%) in the initial 201Th defect (n = 12) were considered ideal candidates for operation (Group 3). Patients with poor or unimproved 201Th uptake after successful intracoronary lysis (n = 6) were treated medically (Group 2), as were patients in whom intracoronary lysis was unsuccessful (n = 5, Group 1). In order to validate this new approach, we compared the change in the regional wall motion of the "infarcted area," as shown in the early and follow-up left ventricular angiograms in all three groups. In the acute stage, the mean regional ejection fraction was 19.9% in Group 1, 19.1% in Group 2, and 20.1% in Group 3. Only in Group 3 was there a significant increase in regional ejection fraction to a mean of 51%. The mean ejection fraction obtained at follow-up in Groups 1 and 2 was 16.5% and 17.3%, respectively. From our findings, we conclude that 201Th scintigraphy is a valuable predictor of the salvageability of myocardium immediately following intracoronary lysis. To date, it has been the most valuable tool in assessing those patients suitable for early coronary revascularization.

Bone scintigraphy in patients with osteogenic sarcoma. Cooperative Osteogenic Sarcoma Study Group COSS 80.

Preliminary results of a comprehensive analysis of bone scans in osteogenic sarcoma are presented. The scintigraphic data from 60 of 184 patients of the COSS-80 study were used for evaluation. The method seems to be appropriate to detect sensitively and early a therapy-induced decrease of tumor viability and extent. An optimized procedure is proposed.

Bone calcium exchange in primary hyperparathyroidism as measured by 47calcium kinetics.

A 2-compartmental analysis of 47Ca kinetics was carried out in 21 patients with primary hyperparathyroidism (pHPT) and 7 healthy control subjects. The results were compared with serum concentrations of calcium, inorganic phosphorus, alkaline phosphatase, and immunoreactive parathyroid hormone (iPTH). The well known increase in exchangeable calcium was found to be not uniform in its subcompartments and with a marked predominance of the osseous fraction. The most important result was the increase of calcium efflux from osseous into extraosseous exchangeable calcium in agreement with the results of Talmage et al. studying PTH actions on calcium flux rates between blood and bone in rats. The increased calcium efflux in pHPT was the only kinetic parameter correlated with serum iPTH. Neither increased calcium accretion indicating high bone turnover, nor serum calcium concentrations and exchangeable calcium fractions correlated with serum iPTH. These results lead to the following conclusions: radiocalcium kinetics provides valuable parameters of bone calcium turnover (osseous exchangeable calcium, bone-calcium efflux, and calcium accretion). Calcium efflux from exchangeable bone calcium, determined kinetically, might be related to PTH induced calcium transport from bone fluid compartment to extracellular fluids according to the concept of Talmage 1977.

[Localization diagnosis of enlarged parathyroid glands: 201Tl-99mTc-subtraction scintigraphy compared with 5-MHz-sonography]. / Lokalisationsdiagnostik vergrösserter Nebenschilddrüsen: die 201Tl-99mTc-Subtraktionsszintigraphie im Vergleich zur 5-MHz-Sonographie.

Fifty patients clinically suspected of having primary hyperparathyroidism were examined by scintigraphy (201Tl-99mTc subtraction) and sonography (5 MHz). In 28 cases, the results of subtraction scintigraphy, and in 26 cases, the results of sonography were checked by operation. In 25 patients there was a solitary parathyroid adenoma and in two, primary hyperplasia. In one patient all four parathyroid glands were normal. Subtraction scintigraphy had a sensitivity of 90% and a specificity of 98%, while sonography had a sensitivity of 82% and a specificity of 95%. The combination of 201Tl-99mTc subtraction scintigraphy as a functional investigation and sonography as a structural imaging method produced a sensitivity of 96% and is therefore superior to all other methods of localisation for normally situated glands. Diagnostic certainty is reduced by the presence of a nodular thyroid.

[Biokinetics of osteotropic radiopharmaceuticals in metabolic osteopathy--comparison of 47Ca and 99mTc-methylene-diphosphonate (MDP)]. / Biokinetik osteotroper Radiopharmaka bei metabolischen Osteopathien--Vergleich von 47Ca und 99mTc-Methylen-Diphosphonat (MDP).

Plasma clearance and osseous accumulation rates of 99mTc methylene diphosphonate (MDP) in the lumbar spine were measured in 11 patients with osteoporosis (OP), 7 patients with hyperparathyroidism (HPT), 4 patients with osteomalacia (OM) and in 3 patients (N) who were studied to exclude metabolic bone disease. The findings in 19 patients were compared with the results of 47Ca kinetics. The plasma elimination of 99mTc-MDP during the first hour after application was normal in almost all the patients. The 99mTc-MDP accumulation rates in the lumbar spine were raised in patients with HPT and OM (p less than or equal to 0.01) and normal in patients with OP and N (p greater than 0.05). 47Ca kinetics were disturbed in most of the patients with metabolic bone disease, with minimal deviations in OP. The comparison of 99mTc-MDP accumulation rates with the results of 47Ca kinetics revealed significant correlations with exchangeable bone and soft tissue calcium. The correlations with total calcium turnover and calcium accretion were poor. Only half of the patients had equal results of 99mTc-MDP accumulation rates and bone calcium accretion rates. It is concluded that the 99mTc-MDP uptake by bone is an index of bone metabolism presumably of the organic matrix, whereas 47Ca kinetics represent the mineral metabolism of bone.

[Function scintigraphy: a uniform method for quantifying organ metabolism and function]. / Funktionsszintigraphie: Eine einheitliche Methode zur Quantifizierung von Stoffwechsel und Funktion in Organen.

Functional scintigraphy is a quantitative method with which metabolic parameters of an organ can be determined by measuring the time activity course of a radioactive tracer in tissue. Their quantitative value is, however, limited by inherent sources of error, e.g. the absorption of radiation in the organ or overlapping of fore- and background activities. Hitherto, existing procedures for calculation of metabolic parameters are based more on given technical possibilities than on common theoretical foundations. They are notable for their variety in methodical approach, frequently being of empirical character. Quantitative results from different institutes and hospitals can therefore rarely be compared. The present work describes a methodical approach to obtain comparable methods in nuclear medicine, by including the pharmacokinetics of a tracer in blood. This leads to the compartment analysis (deterministic) or to a stochastic (non-deterministic) description of the kinetics in an organ. The stochastic description requires the calculation of the linear response function from a convolution integral. By means of functional analytical methods a mathematical procedure has been developed which for the first time permits the calculation of the linear response function in each pixel and at any time of the study. Easily readable functional images show how relevant parameters can be calculated from the linear response function. Due to its independence on any model, the linear response function enables furthermore a regional investigation of existing or new compartment models of tracer kinetics in the organ concerned.

Immunoscintigraphy with combinations of various monoclonal antibodies--studies on xenografts of human gastrointestinal carcinomas.

In order to investigate whether combinations of monoclonal antibodies (MAbs) allow a more sensitive and valid localisation of tumors by immunoscintigraphy compared to the application of single MAbs we injected 3.7 MBq/animal of various 131I-labelled MAbs (anti-CA 19-9, -CA 125, -CEA, BW 494/32, 431/31) or equivalent combinations thereof into NuNu-Balb-C mice bearing xenografts of human gastrointestinal tumors. In addition, "dose response curves" were calculated in order to evaluate the results for different total doses. As parameters we mainly used quality of the scans, fractional uptake of injected dose and tumor/blood or tumor/organ ratios. The results do not support the concept that "cocktails" of MAbs improve the results of immunoscintigraphy. In contrast, a single MAb should be used for clinical immunoscintigraphy, preferably the most appropriate one according to the results of serum determinations of the corresponding tumor-associated antigens or of immunohistochemistry. Cocktails or consecutive applications of different MAbs for immunoscintigraphy should be restricted to cases without dominant tumor-associated antigen and corresponding MAb, respectively, and to patients in whom a first trial with a first single MAb failed.

[Immunoscintigraphy and SPECT in patients with pancreatic cancer]. / Immunszintigraphie und SPECT bei Patienten mit Pankreaskarzinom.

Encouraged by reports on immunoscintigraphy of colorectal carcinomas and by the results of our own immunohistochemical and immunoscintigraphic studies in nude mice with transplanted pancreatic carcinoma, we studied the diagnostic potential of immunoscintigraphy with a cocktail of 131I-labeled monoclonal antibodies against the tumor markers CA 19-9 and CEA in 21 patients with pancreatic cancer disease. The results were compared with those of 10 patients suffering from colorectal tumors, 2 cases with bile duct carcinoma and 1 with gastric cancer. Planar scintigraphy with 2-4 views was done repeatedly within 6 days after i.v infusion of 2 mCi of the antibody cocktail. SPECT was performed 3-4 days p.i., recently at 1 or 2 days, too. Primary tumors and metastases in the upper abdominal parts were more difficult to detect and to localise in comparison to colorectal cancer in the lower parts of the abdomen, because of relatively high tracer accumulation in kidneys, liver and spleen. Tumor enhancement in planar scintigrams was, in most cases, not recognized prior to 5 or 6 days p.i., but by SPECT 3 days p.i. or even earlier. Localisation and topographic determination were much easier and more frequent with SPECT, so that tumor detection became more reliable and sensitive. Large tumors could be detected in some cases without tumor marker concentrations in serum being elevated. Immunoscintigraphy of pancreatic carcinomas and of other cancer manifestations in the upper abdomen up to now seems to be of limited diagnostic value, the techniques involved need to be improved.

Immunoscintigraphy and radioimmunotherapy in patients with pancreatic carcinoma.

A new monoclonal antibody (BW 494/32) labeled with 131I or 111In was used for planar and tomographic immunoscintigraphy (IS) in patients with pancreatic carcinoma. It appears that IS for pancreatic carcinoma and its metastases remains a hopeful but still difficult procedure and labeling with 111In is of advantage and results in more convincing images in the case of tumor lesions distant from liver and spleen. Attempts at radioimmunotherapy with 131I-anti-CA 19-9 and with 131I-494/32 in a patient with local recurrence of a pancreatic cancer and with large liver metastases were without success because of extremely poor blood supply to the metastatic tumor masses. Intraarterial infusion of the tracer without or with blockade and perfusion of the common hepatic artery with saline solution could not enhance the tracer uptake compared to that after intravenous infusion. High intratumoral concentrations, however, as achieved e.g. by intratumoral instillation in animal studies, represent a necessary precondition for effective beta-irradiation of tumor lesions.

[Diagnostic accuracy of FT3-RIA and FT4-RIA compared to total T3-RIA and total T4-RIA]. / Diagnostische Treffsicherheit von FT3-RIA und FT4-RIA im Vergleich zu Gesamt-T3-RIA und Gesamt-T4-RIA.

The values of FT3-serum concentration (Amerlex-RIA) from 311 patients and the FT4-values (Amerlex-RIA) from 745 patients were compared with the total T3- and total T4-values with regard to their diagnostic accuracy in hypo-, eu- and hyperthyroidism. The classification of patients into these three diagnostic categories was determined by the majority of available parameters. The analysis of the predictive values demonstrated that determination of free hormones usually guarantees a safe distinction between hypo-, eu- and hyperthyroidism. Taking into account prevalence, the determination of free hormones appears to be superior to that of total hormones.

Radioimmunotherapy of xenografts of human pancreatic carcinomas--intravenous and intratumoral application of 131I-labelled monoclonal antibodies.

The effects of radioimmunotherapy were tested in xenografts of 2 different human pancreatic carcinomas comparing the intravenous and intratumoral application. On principle, intravenous injections of high doses of 131I-anti-CA 19-9 or -BW 494/32 may inhibit tumor growth. In view of the low direct radiation dose (360-2100 rad), however, other factors than direct toxic effects have to be discussed, e.g. systemic effects due to the high whole-body irradiation. Intratumoral application, however, may induce tumor regression or growth inhibition due to the high local irradiation dose. Consequently, this treatment modality might be of clinical value at least in some patients.

Quantification of tracer kinetics in intra- and extrahepatic bile ducts and of gallbladder filling rates in hepatobiliary dynamic scintigraphy using 99mTc-IDA derivates.

A method is presented of calculating the flow of 99mTc-labelled IDA derivates in intra- and extrahepatic bile ducts. By computer means the superimposed liver parenchymal activity is subtracted from the original sequence data in each pixel and at each time. In addition to known evaluation methods, the described procedure seems to be helpful for clinical application in order to better display anatomical details of intrahepatic structures like bile ducts and to calculate quantitative parameters like appearance times in intra- and extrahepatic regions. Examples are given and the possibility of calculating a gallbladder filling rate for separating normal gallbladders from stone-filled ones is statistically proven.

Localization of post-infarction myocardial ischemia by 201Tl emission computed tomography.

In 41 patients with a history of a single myocardial infarction, the location of myocardial ischemia was studied by 201Tl emission computed tomography immediately and 3 h after intravenous dipyridamole. Distant ischemia was distinguished from periinfarctional ischemia by the presence of transient thallium defects in, or slow thallium washout from, myocardium not supplied by the infarct-related coronary artery. Distant ischemia occurred in 13 patients and was always accompanied by peri-infarctional ischemia. Peri-infarctional ischemia without distant ischemia was observed in 15 patients. The occurrence of distant ischemia was found to be dependent on the severity of stenosis in non-infarct coronary vessels. Twelve (86%) of 14 patients with non-infarct stenosis of 75% or greater had distant ischemia, but only 1 (4%) of 27 patients with non-infarct stenosis of less than 75%. In the presence of distant ischemia, peri-infarctional ischemia was in 11 patients (85%) of the patients with peri-infarctional ischemia only, incomplete obstruction of the infarct vessel was observed. It is concluded that, by the distinction between peri-infarctional and distant ischemia, the presence of significant stenosis in non-infarct vessels can be non-invasively predicted from tomographic thallium scintigraphy with dipyridamole.

[The 4 hr-washout-functional picture: a quantitative visualization of 201Tl myocardial stress kinetics and the significance of paradoxical redistribution]. / Das 4 h-Washout-Funktionsbild: Eine quantitative Darstellung der 201Tl-Kinetik im Herzmuskel nach Belastung--zugleich Deutung der "paradoxen Redistribution".

Between March and August 1983, 62 patients with suspected coronary artery disease were investigated by both 201Tl myocardial scintigraphy and coronary angiography. Functional images of the 4 h-201Tl-washout were compared with conventional scintigrams of the stress and rest phases and with results of coronary angiography. Myocardial scintigraphy with 4 views was performed immediately after exercise and 3-4 h later. After interpolative background subtraction, 4 h-washout functional images were computed from each of the initial scintigrams and the corresponding delayed scintigrams. Using a special-coded colour table, the 4 h-washout could be read quantitatively from the functional image. The additional analysis of washout images increased the accuracy of myocardial 201Tl scintigraphy for the detection and localization of coronary stenoses from 42% to 69%. Sensitivity increased from 42% to 73%, definitivity from 50% to 79%. Ischemic regions appeared more obvious in the washout images, even to less experienced observers. In comparison with circumferential washout profiles the interpretation of washout images was easier because of more obvious anatomical localization. The phenomenon of "reverse redistribution" was found to be associated with a decreased 201Tl-washout in apparently "normal" regions, whereas in those regions with "reverse redistribution" the washout was normal or at least relatively high. In addition diffuse myocardial ischemia occurring in 3-vessel disease could be recognized in the 4 h-washout functional images.