Introduction and objectives. The correct interpretation of myocardial perfusion single photon emission computed tomography (SPECT) requires knowledge of the technique reproducibility.The objective was analyze the interobserver correlation of different experience in the interpretation of myocardial perfusion SPECT in patients following acute myocardial infarction (AMI) in order to improve the quality of our site.Methods. Sixty cases (56 +/- 11 years, 87 % men) with transmural AMI who had recently undergone successful thrombolysis were included. Resting perfusion with Tc-99m-sestamibi was performed at one week post-AMI.Analysis. Semiquantitative interpretation using 17 segment-model by 2 independent specialists and 5 observers, was performed blindly. Left ventricular ejection fraction (LVEF) was measured with isotopic ventriculography one month after AM 1, with a mean of 38 %.Results. Using independent and then agreed on perfusion analysis, average involved segments/patient was 9.3 +/- 4 and the sum of severity 25 +/- 13. Readings of other observers ranged from 7 +/- 3.7 to 9.4 +/- 3.9 and 16.7 +/- 9.7 to 24.6 +/- 13, respectively, consistent with the reading of the specialists of between 0.779-0.871 (kappa: 0.565-0.741). There was no significant difference when the number of segments were analyzed in 40 % of the cases and for intensity in 60 % of them in more experienced observers. Correlation with consensus reading for the number of segments ranged from 0.84 to 0.94 and for severity from 0.79 to 0.89. Identification of culprit arteries was acceptable, with r values between 0.612 and 0.683 and kappas between 0.629 and 0.656. Correlation of the number of involved segments and severity with LVEF performed one month after AMI was 0.73 and 0.74, respectively.Conclusions. There was good correlation in the interpretation of myocardial perfusion SPECT, with a significantly better fit in more experienced observers. This academic exercise was also helpful in improving our residents' skills in cardiology.

La interpretación de la tomografía de emisión de fotón único (SPECT) de perfusión miocárdica requiere conocer la reproducibilidad de la técnica. El objetivo fue analizar la correlación interobservadores de distinta experiencia en interpretación de SPECT en pacientes post-infarto agudo de miocardio (IAM) en un contexto de mejora de la calidad de nuestros centros. Se incluyeron 60 casos (56 ± 11 años, 87% hombres) con infarto transmural reciente sometidos a trombolisis exitosa. Una semana después del IAM se efectuó perfusión de reposo con 99mTc-sestamibi. Semicuantitativo mediante lectura ciega por 2 especialistas independientes y 5 observadores utilizando 17 segmentos. La fracción de eyección ventricular izquierda (FEVI) promedio medida con ventriculografía isotópica al mes fue del 38%. En análisis consensuado, el promedio de segmentos comprometidos/paciente fue 9,3 ± 4 y la sumatoria de severidad 25 ± 13; los otros observadores variaron entre: 7 ± 3,7-9,4 ± 3,9 y 16,7 ± 9,7-24,6 ± 13, respectivamente, concordando con los especialistas entre 0,779 y 0,871 (kappa: 0,565-0,741). No hubo diferencia significativa en el 40 % de los análisis para el número de segmentos comprometidos y en el 60% para intensidad, en observadores con mayor experiencia. La correlación con consenso para el número de segmentos varió entre 0,84 y 0,94, y para severidad entre 0,79 y 0,89. La asignación de arterias fue adecuada (r: 0,612-0,683 y kappas 0,629-0,656). La correlación de segmentos comprometidos y su severidad con la FEVI efectuada al mes del IAM fueron de 0,73 y 0,74, respectivamente. Existió buena correlación en interpretación de SPECT, con mejor ajuste en observadores experimentados. Este ejercicio sirvió para mejorar habilidades de interpretación en cardiología. The correct interpretation of myocardial perfusion single photon emission computed tomography (SPECT) requires knowledge of the technique reproducibility. The objective was analyze the interobserver correlation of different experience in the interpretation of myocardial perfusion SPECT in patients following acute myocardial infarction (AMI) in order to improve the quality of our site. Sixty cases (56 ± 11 years, 87 % men) with transmural AMI who had recently undergone successful thrombolysis were included. Resting perfusion with 99mTc-sestamibi was performed at one week post-AMI. Semiquantitative interpretation using 17 segment-model by 2 independent specialists and 5 observers, was performed blindly. Left ventricular ejection fraction (LVEF) was measured with isotopic ventriculography one month after AMI, with a mean of 38%. Using independent and then agreed on perfusion analysis, average involved segments/patient was 9.3 ± 4 and the sum of severity 25 ± 13. Readings of other observers ranged from 7 ± 3.7 to 9.4 ± 3.9 and 16.7 ± 9.7 to 24.6 ± 13, respectively, consistent with the reading of the specialists of between 0.779-0.871 (kappa: 0.565-0.741). There was no significant difference when the number of segments were analyzed in 40 % of the cases and for intensity in 60 % of them in more experienced observers. Correlation with consensus reading for the number of segments ranged from 0.84 to 0.94 and for severity from 0.79 to 0.89. Identification of culprit arteries was acceptable, with r values between 0.612 and 0.683 and kappas between 0.629 and 0.656. Correlation of the number of involved segments and severity with LVEF performed one month after AMI was 0.73 and 0.74, respectively. There was good correlation in the interpretation of myocardial perfusion SPECT, with a significantly better fit in more experienced observers. This academic exercise was also helpful in improving our residents’ skills in cardiology.

BACKGROUND:99mTc red blood cell scintigraphy is a non invasive diagnostic method for low flow gastrointestinal bleeding.AIM:To assess the diagnostic yield of this method in patients admitted with gastrointestinal bleeding in whom upper gastrointestinal endoscopy was negative.PATIENTS AND METHODS:The clinical records of 59 patients, aged 6 to 90 years old (35 male), with active gastrointestinal bleeding subjected to a 99mTc red blood cell scintigraphy were reviewed. All had non diagnostic upper gastrointestinal endoscopic studies, and in 20 a selective arteriography was performed.RESULTS:In 40 patients the scintigraphy was positive for gastrointestinal bleeding, and in 57% of these the exam was positive during the first hour. Fifteen of the 19 patients with a negative scintigraphy did not have an active clinical bleeding at the moment of the examination. In 24 patients, a final etiological diagnosis was reached. In 93% of these patients scintigraphy correctly identified the bleeding site. In one patient with a negative scintigraphy, angiography disclosed a pseudo aneurysm of the splenic artery that was not bleeding actively.CONCLUSIONS:In these patients with negative upper gastrointestinal endoscopy 99mTc red blood cell scintigraphy had a 91% sensitivity for the diagnosis of active gastrointestinal bleeding.

Background: A temporal alteration between atrial and ventricular contraction, in which the last one would be abnormally retarded, could exist in patients with dilated cardiomyopathy. This alteration could have adverse hemodynamic effects. Aim: To study the hemodynamic modifications caused by an artificial shortening of AV interval In patients with dilated cardiomyopathy. Patients and methods: Nine patients with dilated cardiomyopathy were studied. Hemodynamic and tissular perfusion values, echocardiographic and radioisotopic ventricular function parameters were measured before and after six hours of AV interval shortening with electrical stimulation of the heart. Results: After electrical stimulation, cardiac output increased from 3.38 +/- 0.8 to 3.87 +/- 0.79 l/min (p < 0.05). Pulmonary capillary pressure decreased from 23.8 +/- 8.9 to 19.8 +/- 9.2 mm Hg (p = NS). There were no significant changes in ventricular function parameters or in systemic and pulmonary pressures. Conclusions: Electrical shortening of AV interval in patients with dilated cardiomyopathy increases cardiac output but does not change ventricular function parameters.

An analysis was performed of 84 patients with a history of myocardial infarction using the thallium-single photon emission computed tomography (SPECT) test and employing the technique of reinjection of the radioisotope Tl-201 at rest. A study was conducted during the period of maximum stress, four hours and one hour after reinjection of 37 MBq of Tl-201. Th, presence and extent of reperfusion was determined. In addition, the incidence of ischaemia was correlated with four clinical parameters which might influence its occurrence: development period of the infarction (greater or less than 30 days), Q wave in the electrocardiogram, prior use of streptokinase, and angina. Twenty-seven patients exhibited partial reperfusion at rest which increased significantly in 14 of the patients after thallium reinjection. Moreover, 22 patients only exhibited reperfusion with reinjection. There was no relation between the clinical parameters evaluated and the incidence of ischaemia. In conclusion, with thallium reinjection 43% more patients can be detected with viable areas of myocardium which are not evident at rest. The clinical parameters evaluated are no help in predicting ischaemia with thallium. The routine use of reinjection is recommended to evaluate myocardial viability in patients with a history of infarction.

153SmEDTMP was obtained from enriched 152Sm irradiated at the 5 MW Chilean Research Reactor and labelled at a molar ratio of 15:1 pH 7.5. Biodistribution, autoradiography, radiochemical purity tests were done for evaluation. 40 patients were treated with 37-55 MBq/kg weight. Bone scans using 99mTcHMDP were obtained prior and after treatment. Bone marrow depression was observed in 37% of them and normal liver function in all of them. In 45% the pain dissapear completely, in 22.5% significantly decreased and partially in 30%. In 17 patients more than one dosis was injected. Our preliminary results indicate that 153SmEDTMP is a promising radiotherapeutic agent for palliative treatment of metastatic bone cancer pain and encourage its use specially because it can be produced in countries with low economic resources, thus a large number of patients can get the benefits of this new procedure.

The aim of the study was to compare single photon emission computed tomography (SPECT) of the spine and bone scan findings in 36 patients with different spinal disorders in order to assess the contribution of tomographic images. All of the patients underwent bone scans with 740 MBq of Tc-99(m)-HMDP (hydroxymethylene diphosphonate). A total of 1 000 000 count static images of the axial skeleton and 360 degrees, 128 projection SPECT images of the spine were obtained. In 16 patients, planar and SPECT images revealed no abnormalities (44%). SPECT showed abnormal focus of radiotracer uptake in the spine in 20 patients (56%), 13 of whom also had an abnormal planar bone scan. It was found that 42% of the lesions detected only in SPECT had vertebral posterior element involvement. Among those with low back pain and showing positive studies, half of the patients with posterior element lesions had lesions detected only with SPECT. All patients with spondylitis proved positive in both planar and SPECT studies. Tomographic images in this group detected two additional foci not suspected in planar images. In conclusion, SPECT is useful in spinal disorders, especially when posterior neural arch involvement is suspected. The routine use of SPECT is recommended in patients with low back pain and exhibiting normal planar images.

Locating the epileptogenic focus in patients with drug resistant temporal lobe epilepsy is essential for pre-surgical evaluation of such cases. This is not always possible with a surface electroencephalogram (EEG) and, for that reason, various diagnostic methods have been used employing morphological and functional images. Of these, the ones which can be best related to the EEG images are interictal positron emission tomography (PET) and ictal single photon emission computed tomography (SPECT). Various studies performed with Tc-99(m)-HMPAO (hexamethypropylene amine oxime) show that the sensitivity of the technique for the location of epileptogenic foci varies between 50 and 70% in the interictal period, but rises to 65-97% if the study is ictal. Recently, the use of Tc-99(m)-ECD (ethyl cysteinate dimer) in such patients has been described and a high level of agreement was found with both clinical and EEG results. The aim was to evaluate the interictal use of Tc-99(m)-ECD in ten patients with partial complex epilepsy where there was no evidence of a structural lesion and compare it with extended computerized video EEG in eight of these patients and with standard EEG in two. In one patient, the SPECT was normal, whereas there was a temporal focus in the EEG. In the nine remaining patients, all the epileptogenic foci showed up as hypoperfused zones in the SPECT. The latter also revealed two zones of hypoperfusion which were not apparent in the EEG. Ictal and interictal SPECT were performed on two patients. Here the epileptogenic foci showed up as hyperperfused areas in the ictal SPECT and areas with diminished or normal perfusion in the interictal SPECT. It is concluded that SPECT with Tc-99(m)-ECD is useful for the pre-surgical evaluation of patients with temporal lobe epilepsy.

(153)SmEDTMP was obtained from enriched Sm-152 irradiated at the 5 MW Chilean Research Reactor and labelled at a molar ratio of 15:1 pH 7.5. Biodistribution, autoradiography, radiochemical purity tests were done for evaluation. 40 patients were treated with 37-55 MBq/kg weight. Bone scans using (93m)TcHMDP were obtained prior and after treatment. Bone marrow depression was observed in 37% of them and normal liver function ill all of them. In 45% the pain dissapear completely, in 22,5% significantly decreased and Partially ill 30%. In 17 patients more than one dosis was injected. Our preliminary results indicate that (153)SmEDTMP is a promising radiotherapeutic agent for palliative treatment of metastatic bone cancer pain and encourage its use specially because it can be produced in countries with law economic resources thus a large number of patients can get, the benefits of this new procedure.

The authors report a case where marked uptake of radiotracer in abdominal muscles was observed after unusual and violent exercise.

Orellana, P.; Baquedano, P.; Garcia, C.; Lagomarsino, E.; Cavagnaro, F.; Olea, E.; Fabres, J. Author Information

Blood pool scintigraphy is a useful tool in the diagnosis of hepatic hemangioma. We reviewed retrospectively the clinical histories of 24 patients with abnormal blood pool scintigraphies and a presumptive diagnosis of hepatic hemangioma, based on clinical or ultrasonographic findings. In 20 of these patients, blood pool scintigraphy was diagnostic for hepatic hemangioma. The diagnosis was confirmed by an asymptomatic clinical evolution of 12 to 78 months in all the patients, CT scan in 8, angiography in 5 and liver biopsy in one. In the remaining 4 patients scintigraphy ruled out the presence of a hepatic hemangioma. Our results are similar to previous reports in the literature and blood pool scintigraphy has a high specificity for the diagnosis of hepatic hemangioma.

The administration of an angiotensin-converting enzyme (ACE) inhibitor transitorily reduces the GFR in a kidney with renal artery stenosis, effect that can be ascertained with scintigraphic studies using ACE inhibitors. We evaluated the clinical usefulness of captopril renography (CR) in the diagnosis of renovascular hypertension (RVH) in 51 hypertensive patients in which this diagnosis was suspected. All subjects underwent angiography and RVH was diagnosed when renal artery stenosis exceded 60%, there was lateralization of renal vein renin or there was a concordant clinical outcome. Renography was performed 15 minutes after Lasix administration, using Tc-99m DTPA, before and 60 minutes after the oral administration of 50 mg of captopril. The scintigraphic criteria for a positive test were a decreased split renal function, a delayed peak uptake, a decreased excretion of DTPA and a prolonged transit time. In three of 28 patients in whom angiography discarded RVH, CR was positive. In the 23 patients with confirmed RVH, CR was positive in 10 of 12 with unilateral stenosis, in 3 of 8 with bilateral stenosis and 1 of 3 with stenosis in a transplanted kidney. The overall sensitivity and specificity of the test for RVH was 60.9% and 89.2% respectively. There were no changes in blood pressure or adverse effects after captopril administration. We conclude that CR in RVH is useful to select patients for further studies (angiography) and to perform a functional interpretation of angiographic alterations.

The administration of an angiotensin-converting enzyme (ACE) inhibitor transitorily reduces the GFR in a kidney with renal artery stenosis, effect that can be ascertained with scintigraphic studies using ACE inhibitors. We evaluated the clinical usefulness of captopril renography (CR) in the diagnosis of renovascular hypertension (RVH) in 51 hypertensive patients in which this diagnosis was suspected. All subjects underwent angiography and RVH was diagnosed when renal artery stenosis exceeded 60%, there was lateralization of renal vein renin or there was a concordant clinical outcome. Renography was performed 15 minutes after Lasix administration, using Tc-99m DTPA, before and 60 minutes after the oral administration of 50 mg of captopril. The scintigraphic criteria for a positive test were a decreased split renal function, a delayed peak uptake, a decreased excretion of DTPA and a prolonged transit time. In three of 28 patients in whom angiography discarded RVH, CR was positive. In the 23 patients with confirmed RVH, CR was positive in 10 of 12 with unilateral stenosis, in 3 of 8 with bilateral stenosis and 1 of 3 with stenosis in a transplanted kidney. The overall sensitivity and specificity of the test for RVH was 60.9% and 89.2% respectively. There were no changes in blood pressure or adverse effects after captopril administration. We conclude that CR in RVH is useful to select patients for further studies (angiography) and to perform a functional interpretation of angiographic alterations.

Blood pool scintigraphy is a useful tool in the diagnosis of hepatic hemangioma. We reviewed retrospectively the clinical histories of 24 patients with abnormal blood pool scintigraphies and a presumptive diagnosis of hepatic hemangioma, based on clinical or ultrasonographic findings. In 20 of these patients, blood pool scintigraphy was diagnostic for hepatic hemangioma. The diagnosis was confirmed by an asymptomatic clinical evolution of 12 to 78 months in all the patients, CT scan in 8, angiography in 5 and liver biopsy in one. In the remaining 4 patients scintigraphy ruled out the presence of a hepatic hemangioma. Our results are similar to previous reports in the literature and blood pool scintigraphy has a high specificity for the diagnosis of hepatic hemangioma.

We evaluated a pre-tinning leukocyte labeling technique using Glucoheptonate-Sn lyophilized kit, in the detection of activity in 15 patients with clinical and laboratory signs of active inflammatory bowel disease (IBD). 25 patients, without gastrointestinal disease were the control group. In 7/8 patients with Crohn's disease and in 7/7 with Ulcerative Colitis the study was positive. The negative study corresponded to a patient who has only involvement of the duodenum, an area of difficult evaluation due to the high liver uptake. 3/25 patients of the control group had activity in the intestine at 4 hour images. In spite of the small group evaluated, we believe that this labeling technique is a promising procedure for evaluation of activity in patients with IBD (Sensitivity 93.3%, Specificity 88.0%).

We evaluated a pre-tinning leukocyte labeling technique using Glucoheptonate-Sn lyophilized kit, in the detection of activity in 15 patients with clinical and laboratoy signs of active inflammatory bowel disease (IBD). 25 patients, without gastrointestinal disease were the control group. In 7/8 patients with Crohn's disease and in 7/7 with Ulcerative Colitis the study was positive. The negative study corresponded to a patient who has only involvement of the duodenum, an area of difficult evaluation due to the high liver uptake. 3/25 patients of the control group had activity in the intestine at 4 hour images. In spite of the small group evaluated, we believe that this labeling technique is a promising procedure for evaluation of activity in patients with IBD (Sensitivity 93,3%, Specificity 88,0%).

Fifty three patients were studied with dipyridamole thallium myocardial scintigraphy, 4 to 6 days after a first episode of myocardial infarction. Localization of infarction was anterior in 25 and inferior in 28. Infarction was confirmed by myocardial scintigraphy in 87% of cases. A non q wave myocardial infarction was present in 5 of the 7 patients with negative scintigraphy. Residual myocardial ischemia was suggested by myocardial scintigraphy in 68% of patients. Correlated to coronary arteriography, sensitivity for myocardial ischemia was 80%, specificity 82%. After a mean follow up of 11.2 months, 22 of 36 patients with positive myocardial scintigraphy had new coronary events, 15 of them requiring myocardial revascularization. In contrast, only 2 of 17 patients with negative scintigraphy had new events (p < 0.05). Thus dipyridamole thallium myocardial scintigraphy early after myocardial infarction is a valuable prognostic test.

We studied 10 male and 2 female normal non-smoker volunteers (mean age 25) by labeling of autologous platelets with 111-In oxine. Daily samples for platelet survival were obtained in all, gamma-camera images in 10 and blood pool digital subtraction with 99m-Tc labeled erythrocytes in 6. Mean platelet count was 594 +/- 235 10(3)/mm3; collagen platelet aggregation pre and post labeling was 74 +/- 4.8 and 70 +/- 10%, respectively. Mean labeling efficacy was 65 +/- 15.4%, mean labeling dose was 201 +/- 79.5 microCi. A linearized initial survival of 7.9 +/- 1 day was obtained. Scintigraphic images showed circulating activity, greater in the spleen, persisting after digital subtraction. The method described can be used for clinical evaluation of platelet disorders and thrombosis.