InmunoPET en oncología / ImmunoPET in oncology

Con el auge de la inmunoterapia en oncología es fundamental tener una caracterización biológica de los tumores. Conocer que antígenos se expresan tanto en la superficie de la célula tumoral como en el microambiente del tumor para poder predecir la respuesta al tratamiento de los diferentes anticuerpos terapéuticos, se ha convertido en una necesidad. La inmunoPET es una herramienta de diagnóstico por imagen, no invasiva, que aúna la elevada especificidad de los anticuerpos frente a los antígenos con la elevada sensibilidad, resolución y capacidad de cuantificación de la imagen PET. Con la inmunoPET obtenemos una biopsia virtual del tumor con un amplísimo presente y futuro en investigación preclínica-clínica, siendo ya una realidad en la predicción y monitorización de la respuesta a los tratamientos con anticuerpos monoclonales, permitiendo una selección de pacientes y terapias alcanzando una autentica medicina personalizada contribuyendo a mejorar las decisiones clínicas (AU)

Due to increase of immunotherapy in oncology, it is essential to have a biological characterization of tumors. Knowing which antigens are expressed both on the surface of the tumor cell and at tumor microenvironment in order to predict the tretment response different therapeutic antibodies, has become a need. ImmunoPET is a non-invasive diagnostic imaging tool that combines the high specificity of antibodies against antigens with the high sensitivity, resolution and quantification capacity of PET imaging. With ImmunoPET we obtain a virtual biopsy of tumors, it has a big present and future in preclinical-clinical research, being already a reality in predicting and monitoring the response to treatments with monoclonal antibodies, allowing a selection of patients and therapies reaching a personalized medicine contributing to improve clinical decisions (AU)

Beneficial effects of manually assisted chiropractic adjusting instrument in a rabbit model of osteoarthritis.

Osteoarthritis (OA) is a degenerative disease characterized by injury of all joint tissues. Our previous study showed that in experimental osteoporosis, chiropractic manipulation (CM) exerts protective effects on bone. We here assessed whether CM might ameliorate OA by improving subchondral bone sclerosis, cartilage integrity and synovitis. Male New-Zealand rabbits underwent knee surgery to induce OA by anterior cruciate ligament injury. CM was performed using the chiropractic instrument ActivatorV 3 times/week for 8 weeks as follows: force 2 setting was applied to the tibial tubercle of the rabbit right hind limb (TM-OA), whereas the corresponding left hind limb received a false manipulation (FM-OA) consisting of ActivatorV firing in the air and slightly touching the tibial tubercle. After sacrifice, subchondral bone integrity was assessed in the tibiae by microCT and histology. Cartilage damage and synovitis were estimated by Mankin's and Krenn's scores, respectively, and histological techniques. Bone mineral density and content in both cortical and trabecular compartments of subchondral bone decreased in OA rabbits compared to controls, but partially reversed in the TM-OA group. Trabecular bone parameters in the latter group also showed a significant improvement compared to FM-OA group. Moreover RANKL, OPG, ALP and TRAP protein expression in subchondral bone significantly decreased in TM-OA rabbits with respect to FM-OA group. CM was associated with lower Mankin's and Krenn's scores and macrophage infiltrate together with a decreased protein expression of pro-inflammatory, fibrotic and angiogenic factors, in TM-OA rabbits with respect to FM-OA. Our results suggest that CM may mitigate OA progression by improving subchondral bone as well as cartilage and synovial membrane status.

Impact of Chiropractic Manipulation on Bone and Skeletal Muscle of Ovariectomized Rats.

Evidence suggests that chiropractic manipulation might exert positive effects in osteoporotic patients. The aim of this study was to evaluate the effects of chiropractic manipulation on bone structure and skeletal muscle in rats with bone loss caused by ovariectomy (OVX). The 6-month old Sprague-Dawley rats at 10 weeks following OVX or sham operation (Sh) did not suffer chiropractic manipulation (NM group) or were submitted to true chiropractic manipulation using the chiropractic adjusting instrument Activator V® three times/week for 6 weeks as follows: Force 1 setting was applied onto the tibial tubercle of the rat right hind limb (TM group), whereas the corresponding left hind limb received a false manipulation (FM group) consisting of ActivatorV® firing in the air and slightly touching the tibial tubercle. Bone mineral density (BMD) and bone mineral content (BMC) were determined in long bones and L3-L4 vertebrae in all rats. Femora and tibia were analyzed by µCT. Mechano growth factor (MGF) was detected in long bones and soleus, quadriceps and tibial muscles by immunohistochemistry and Western blot. The decrease of BMD and BMC as well as trabecular bone impairment in the long bones of OVX rats vs Sh controls was partially reversed in the TM group versus FM or NM rats. This bone improvement by chiropractic manipulation was associated with an increased MGF expression in the quadriceps and the anterior tibial muscle in OVX rats. These findings support the notion that chiropractic manipulation can ameliorate osteoporotic bone at least partly by targeting skeletal muscle.

Targeting MT1-MMP as an ImmunoPET-Based Strategy for Imaging Gliomas.

BACKGROUND: A critical challenge in the management of Glioblastoma Multiforme (GBM) tumors is the accurate diagnosis and assessment of tumor progression in a noninvasive manner. We have identified Membrane-type 1 matrix metalloproteinase (MT1-MMP) as an attractive biomarker for GBM imaging since this protein is actively involved in tumor growth and progression, correlates with tumor grade and is closely associated with poor prognosis in GBM patients. Here, we report the development of an immunoPET tracer for effective detection of MT1-MMP in GBM models. METHODS: An anti-human MT1-MMP monoclonal antibody (mAb), LEM2/15, was conjugated to p-isothiocyanatobenzyl-desferrioxamine (DFO-NCS) for 89Zr labeling. Biodistribution and PET imaging studies were performed in xenograft mice bearing human GBM cells (U251) expressing MT1-MMP and non-expressing breast carcinoma cells (MCF-7) as negative control. Two orthotopic brain GBM models, patient-derived neurospheres (TS543) and U251 cells, with different degrees of blood-brain barrier (BBB) disruption were also used for PET imaging experiments. RESULTS: 89Zr labeling of DFO-LEM2/15 was achieved with high yield (>90%) and specific activity (78.5 MBq/mg). Biodistribution experiments indicated that 89Zr-DFO-LEM2/15 showed excellent potential as a radiotracer for detection of MT1-MMP positive GBM tumors. PET imaging also indicated a specific and prominent 89Zr-DFO-LEM2/15 uptake in MT1-MMP+ U251 GBM tumors compared to MT1-MMP- MCF-7 breast tumors. Results obtained in orthotopic brain GBM models revealed a high dependence of a disrupted BBB for tracer penetrance into tumors. 89Zr-DFO-LEM2/15 showed much higher accumulation in TS543 tumors with a highly disrupted BBB than in U251 orthotopic model in which the BBB permeability was only partially increased. Histological analysis confirmed the specificity of the immunoconjugate in all GBM models. CONCLUSION: A new anti MT1-MMP-mAb tracer, 89Zr-DFO-LEM2/15, was synthesized efficiently. In vivo validation showed high-specific-contrast imaging of MT1-MMP positive GBM tumors and provided strong evidence for utility of MT1-MMP-targeted immunoPET as an alternate to nonspecific imaging of GBM.

Evaluation of the foetal time to death in mice after application of direct and indirect euthanasia methods.

Directive 2010/63/EU on the protection of animals used for scientific purposes requires that the killing of mammal foetuses during the last third of their gestational period should be accomplished through effective and humane methods. The fact that murine foetuses are resistant to hypoxia-mediated euthanasia renders the current euthanasia methods ineffective or humane for the foetuses when these methods are applied to pregnant female mice. We have assessed the time to death of foetuses after performing either indirect (dam euthanasia) or direct (via intraplacental injection--a new approach to euthanasia) euthanasia methods in order to determine a euthanasia method that is appropriate, ethical and efficient for the killing of mouse foetuses. The respective times to death of foetuses after performing the three most commonly used euthanasia methods (namely cervical dislocation, CO2inhalation and intraperitoneal sodium pentobarbital administration) were recorded. Absence of foetal heartbeat was monitored via ultrasound. We consider that the most effective and humane method of foetal euthanasia was the one able to achieve foetal death within the shortest possible period of time. Among the indirect euthanasia methods assessed, the administration of a sodium pentobarbital overdose to pregnant female mice was found to be the fastest for foetuses, with an average post-treatment foetal death of approximately 29.8 min. As for the direct euthanasia method assessed, foetal time to death after intraplacental injection of sodium pentobarbital was approximately 14 min. Significant differences among the different mouse strains employed were found. Based on the results obtained in our study, we consider that the administration of a sodium pentobarbital overdose by intraplacental injection to be an effective euthanasia method for murine foetuses.

Doppler ultrasonographic and scintigraphic assessment of an auxiliary heterotopic liver transplantation with portal vein arterialization in pigs.

OBJECTIVE: Our aim was to evaluate liver graft integrity and function using scintigraphy and ultrasonography in a porcine model of auxiliary heterotopic liver transplantation with portal vein arterialization (AHLT-PVA). MATERIALS AND METHODS: Using Doppler ultrasonography we evaluated eight AHLT-PVA by parenchymal echogenicity, portal and arterial anatomy, and portal and biliary system flow. Two types of scintigraphy were performed: microaggregated human albumin colloid scintigraphy and diisopropyl iminodiacetic acid (DISIDA) scintigraphy, both labeled with 99mTc. RESULTS: The animals were distributed into two groups. The first group consisted of three animals with clinical suspicion of graft dysfunction, in which the ultrasonographic study revealed areas of parenchymal destructuring. In the scintigraphic study, heterogenous uptake was observed; there was no uptake in one animal. Necropsy of these three animals revealed areas of graft necrosis. The second group consisted of five animals with good clinical evolutions, in which the ultrasonographic study showed portal dilation, portal flow with arterial spiculations, and homogenous echogenicity of the hepatic parenchyma. The scintigraphic study revealed homogenous uptake by the graft and an elimination speed of the hepatobiliary agent similar to that of the native liver. CONCLUSIONS: An heterogenous echostructure of the graft provided a sign of poor prognosis indicating necrosis in the same way as heterogenous uptake or nonuptake of radioisotope upon scintigraphy. Scintigraphy is a good method to evaluate biliary function and bile elimination. In an AHLT-PVA, the main ultrasound findings derived from arterialization were dilation of the portal system and portal flow with arterial spiculations.

Fiebre de origen desconocido (FOD), gammagrafía con citrato de galio-67 y linfoma maligno de partes blandas / Fever of unknown origin (FUO), scintigraphy with Gallium 67 citrate scintigraphy and malignant lymphoma of soft tissues

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Vasoregulatory function of the heme-heme oxygenase-carbon monoxide system.

Arterial vessels express one or more heme oxygenase (HO) isoenzymes that catalyze the metabolism of heme to carbon monoxide (CO) and biliverdin. Carbon monoxide promotes vasorelaxation through mechanisms that, depending on the vessels, involve activation of soluble guanylate cyclase, stimulation of calcium-activated potassium channels, or diminished synthesis of constrictor mediators, such as, endothelin and 20-HETE. Inhibitors of HO elicit vasoconstriction in vivo and in isolated pressurized arterioles. Inhibitors of HO also enhance myogenic vasoconstriction, as well as the constriction induced by phenylephrine in several vessels. The blood pressure of awake rats is increased by acute treatment with HO inhibitors, a response that is accompanied by attenuation of baroreflex activity. All in all, it would appear that a product of HO activity manufactured by arterial vessels, presumably CO, promotes vasodilation and decreases the reactivity of vascular smooth muscle to myogenic stimuli and constrictor agonists. In doing so, CO of vascular origin may contribute to the implementation of antihypertensive mechanisms. Carbon monoxide produced in central nervous system structures, for example, the nucleus tractus solitarii, also appears to support a blood pressure-lowering mechanism linked to inhibitory modulation of baroreceptor reflex activity.

[Scintigraphy with 99mTc-MIBI in the diagnosis of axillary lymph node invasion of breast cancer]. / Gammagrafía con 99mTc-MIBI en el diagnóstico de la invasión ganglionar axilar del cáncer de mama.

UNLABELLED: The presence of affected locoregional lymph nodes should be considered as one of the most important prognostic factors of breast cancer. At present, the clinician is conditioned by an absolute lack of an efficient methodology to evaluate the possible invasion of the axillary lymph nodes, which if negative, would make it possible to avoid surgical excision. In this study, we will evaluate the use of the 99mTc-MIBI scintigraphy in the pre-surgical diagnosis of axillary lymph node invasion and will analyze the relationship between the 99mTc-MIBI uptake and the number of lymph nodes affected. MATERIAL AND METHODS: 84 patients diagnosed of breast cancer were analyzed in this study. All of them underwent a 99mTc-MIBI scintigraphy, and the tumor/background ratio was determined semiquantitively for each image. The axillary lymph node invasion was determined following surgery. RESULTS: The sensitivity of the breast scintigraphy with 99mTc-MIBI for detection of lymph node invasion is 36% and the specificity is 100%. The positive predictive value is 100% and the negative one 48%. In the current study, we failed to detect correlation between the intensity of 99mTc-MIBI uptake in the primary tumor and the number of affected axillary lymph nodes. CONCLUSION: 99mTc-MIBI breast scintigraphy can provide complementary information for the presurgical diagnosis of breast cancer axillary lymph node invasion. 99mTc-MIBI breast scintigraphy shows high specificity and a high predictive value.

[Usefulness of quantification and visual analysis of the uptake of (99m)Tc-MIBI in the diagnosis of mammary lesions]. / Utilidad de la cuantificación y análisis visual de la captación de (99m)Tc-MIBI en el diagnóstico de lesiones mamarias.

OBJECTIVE: Scintigraphy studies with (99m)Tc-MIBI are widely used in the diagnosis of non-invasive breast cancer and their results have been verified by many studies. However, the scintigraphic technique produces erroneous false negative and positive results. This study aims to verify how the different characteristics of the uptake of (99m)Tc-MIBI (intensity, size, morphology, etc.) can help to increase sensitivity and specificity of breast scintigraphy. MATERIALS AND METHODS: We have studied 201 patients (84 breast cancer and 117 benign lesions). All of them underwent a breast scintigraphy with (99m)Tc-MIBI and anatomopathological study. A semiquantitative analysis (by T/F indexes) and visual study were performed in the lesions that presented radiodrug uptake. RESULTS: Eleven false positive results and 8 false negative results were obtained in the study of the 201 patients. The analysis of the T/F indexes did not demonstrate any significant differences between the benign and malignant lesions (p>0,05). There is a statistically significant correlation (p<0.05) between the tracer uptake morphology and the AP diagnosis and between the localization of the lesion in a breast quadrant and the uptake intensity. CONCLUSIONS: Quantification of (99m)Tc-MIBI uptake by T/F indexes does not provide any conclusive data on the lesion's malignancy, however, a more detailed analysis of the characteristics of the tracer uptake would permit us to make the correct diagnosis and would reduce the false positive and negative results of this technique.

[Usefulness of the quantification of (99M)Tc-MIBI uptake in breast neoplasms in the preoperative assessment of tumor aggressiveness]. / Utilidad de la cuantificación de la captación de (99m)Tc-MIBI en neoplasias mamarias en la valoración preoperatoria de la agresividad tumoral.

UNLABELLED: (99m)Tc-MIBI has been proposed as an imaging diagnostic method in a large variety of human malignant tumors. At present, the mechanism by which (99m)Tc-MIBI is uptaken and concentrated by the malignant cells is not totally known. Some mammary neoplasms do not show any uptake of (99m)Tc-MIBI. This study aims to determine if there is any correlation between the uptake of (99m)Tc-MIBI by the tumor and the different histopathological parameters involved in tumoral aggressiveness. To do so, we have studied 100 patients with breast cancer. All of them underwent a breast scintimammography with (99m)Tc-MIBI with semiquantitative analysis by means of a tumor-to-background ratio calculated in every projection. After surgery, an experienced pathologist determined tumor size, axillary lymph node metastases, histological grade (Scarff Bloom Richardson) (SCBR), nuclear grade, mitotic index, presence of cellular atypia and estrogen and progesterone receptor expression. RESULTS: A statistically significant correlation (p < 0.005) has been found between tumor-to-background (T/B) ratios of (99m)Tc-MIBI uptake and tumor SCBR histological grade. A correlation between (99m)Tc-MIBI uptake and the mitotic index, cellular atypia and nuclear grade has also been found. No correlation was found in our study with tumor size, hormone receptor expression or axillary lymph node metastases. CONCLUSIONS: (99m)Tc-MIBI uptake in breast cancer is correlated with the tumoral differentiation grade: the smaller the tumoral cellular differentiation (greater aggressiveness), the greater the uptake. On the other hand, no correlation was found between the uptake of (99m)Tc-MIBI and the classical pathological parameters that define tumoral aggressiveness, such as size and axillary lymph node metastasis.

[99m Tc-MIBI scintigraphy compared to mammography in the diagnosis of breast cancer in dense, operated and young women breasts]. / Gammagrafía con 99mTc-MIBI frente a la mamografía en el diagnóstico de cáncer de mama en mamas densas, mamas intervenidas y mujeres jóvenes.

UNLABELLED: Breast scintimammography with 99mTc-MIBI has proven to be a useful complement to mammography in the diagnosis of breast cancer in the female population. Although the mammography, along with a physical examination, is the backbone of breast cancer diagnosis, there are groups of patients in whom the mammography has an even lower specificity. OBJECTIVE: Our study has aimed to assess the usefulness of breast 99mTc-MIBI scintimammography in those situations in which the mammography was indeterminate, such as, in dense breasts, young females or breasts with architectural distortion after surgery or radiation therapy. MATERIALS AND METHODS: We studied 109 females with mammographically dense breasts, 8 young females under 30 and 24 patients who had undergone previous surgery or radiation therapy. All cases were studied to rule out breast cancer. Final diagnosis was established with excisional biopsy. RESULTS: In dense breasts MIBI scintimammography sensitivity was 88% and the mammography one 81%. MIBI scintimammography specificity was 90% and the mammography 28%. In young females MIBI scintimammography sensitivity was 100% and the mammography 50%, MIBI scintimammography specificity 100% and the mammography 20%. In previous surgery, MIBI scintimammography sensitivity was 80% and the mammography 80%, MIBI scintimammography specificity 100% and the mammography 42%. CONCLUSION: Breast scintimammography with 99mTc-MIBI is an excellent diagnostic technique with high specificity. Undoubtedly it is complementary to mammography in those cases where mammography has major limitations such as dense breasts, young females and breasts with severe scarring after surgery or radiation therapy.

Gammagrafía con 99m Tc-MIBI en el diagnóstico de la invasión ganglionar axilar del cáncer de mama / Scintigraphy with 99mTc-MIBI of the axillary lymph node invasion of the breast cancer

La presencia de ganglios locorregionales afectados debe considerarse como uno de los factores pronósticos más importantes en el cáncer de mama. En la actualidad el clínico está condicionado por la absoluta falta de una metodología capaz de proporcionar un juicio preoperatorio atendible sobre los ganglios axilares que, en caso de negatividad, permita evitar su extirpación quirúrgica. En nuestro estudio pretendemos evaluar la utilidad de la gammagrafía mamaria con 99mTc-MIBI en el diagnóstico preoperatorio de la invasión ganglionar axilar y analizar la relación entre la captación del radiofármaco y la presencia de mayor número de ganglios afectados.Material y método: Estudiamos 84 pacientes con cáncer de mama. A todas ellas se les realizó gammagrafía mamaria con 99mTc-MIBI calculándose mediante un análisis semicuantitativo la ratio tumor/fondo en cada proyección. Tras la cirugía se determinó la invasión ganglionar axila.Los resultados de la gammagrafía mamaria con 99mTc-MIBI en la detección de invasión ganglionar axilar fueron sensibilidad 36 por ciento, especificidad 100 por ciento, valor predictivo positivo 100 por ciento y valor predictivo negativo 48 por ciento. En nuestro estudio no encontramos correlación entre la captación de 99mTc-MIBI en la lesión primaria y el número de ganglios axilares invadidos.Conclusión: La gammagrafía mamaria con 99mTc-MIBI puede aportar datos complementarios al diagnóstico pre-operatorio de la invasión ganglionar axilar, basándonos en la elevada especificidad y valor predictivo positivo de la técnica. (AU)

Gammagrafía con 99m Tc-MIBI frente a la mamografía en el diagnóstico de cáncer de mama en mamas densas, mamas intervenidas y mujeres jóvenes / 99m Tc-MIBI scintingraphy compared to the mammography in the diagnosis of breast cancer in dense, operated and young women's breasts

La gammagrafía mamaria con 99mTc-MIBI ha demostrado ser de utilidad como complemento a la mamografía en el diagnóstico del cáncer de mama. Existen grupos concretos de pacientes en las que la mamografía encuentra aún más disminuida su especificidad.Objetivo: En este estudio nos planteamos valorar la utilidad de la gammagrafía mamaria con 99mTc-MIBI, en aquellas situaciones que mamográficamente plantean problemas diagnósticos, como ocurre en las pacientes con: mamas densas, mujeres jóvenes y mamas intervenidas y radiadas.Material y Método: Estudiamos un total de 201 pacientes; 109 pacientes con patrón mamográfico de mamas densas, 8 pacientes menores de 30 años y 24 pacientes con mamas intervenidas y radiadas. Los resultados fueron en el diagnóstico de mamas densas una sensibilidad del 88 por ciento para el MIBI frente al 81 por ciento para la mamografía y especificidad del 90 por ciento frente al 28 por ciento. En las mujeres menores de 30 años la sensibilidad para el MIBI fue del 100 por ciento frente a la mamografía con sensibilidad del 50 por ciento, la especificidad fue del 100 por ciento frente al 20 por ciento. En las mujeres con mamas intervenidas, MIBI sensibilidad 80 por ciento frente a mamografía 80 por ciento, especificidad MIBI 100 por ciento y mamografía 42 por ciento.Conclusiones: La gammagrafía mamaria con 99mTc-MIBI es una excelente técnica de diagnóstico, por su elevada especificidad, complementando a la mamografía en el diagnóstico de cáncer de mama en pacientes con mamas densas, mujeres jóvenes y mamas intervenidas y radiadas (AU)

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Utilidad de la cuantificación de la captación de 99mTc-MIBI en neoplasias mamarias en la valoración preoperatoria de la agresividad tumoral / Usefulness of the quantification of 99mTc-MIBI uptake in mammary neoplasms in the pre-operative assessment of tumor aggressiveness

La gammagrafía con 99mTc-MIBI se ha propuesto como método de diagnóstico por imagen de una gran variedad de tumores malignos. En el momento actual, el mecanismo por el cual las células malignas captan y concentran el 99mTc-MIBI no es del todo conocido. Algunas neoplasias mamarias no muestran captación de 99mTc-MIBI. El objetivo de este estudio es determinar si existe correlación entre la captación de 99mTc-MIBI por parte del tumor y distintos parámetros anatomopatológicos implicados en la agresividad tumoral.Para ello se ha estudiado 100 pacientes con cáncer de mama. A todas ellas se les realizó gammagrafía mamaria con 99mTc-MIBI calculándose mediante un análisis semicuantitativo la ratio tumor/fondo en cada proyección. Tras la cirugía se determinó el tamaño tumoral, invasión ganglionar axilar, grado histológico (Scarff Bloom Richardson), grado nuclear, índice mitótico, presencia de atipia y receptores hormonales (estrógenos y progesterona).Resultados: Hemos encontrado una correlación estadísticamente significativa (p < 0,05) entre la ratio tumor/fondo de la captación de 99mTc-MIBI y el grado histológico SCBR. También se ha hallado correlación entre la captación de 99mTc-MIBI y el índice mitótico, la atipia celular y el grado nuclear. En nuestro estudio no encontramos correlación entre la captación de 99mTc-MIBI y el tamaño tumoral, la expresión de receptores hormonales y la presencia de invasión ganglionar axilar.Conclusiones: La captación del 99mTc-MIBI en el cáncer de mama está correlacionado con el grado de diferenciación tumoral: A menor diferenciación celular tumoral (mayor agresividad) mayor captación. Por otro lado no se ha encontrado correlación entre la captación de 99mTc-MIBI y los parámetros anatomopatológicos clásicos que definen la agresividad tumoral, como son el tamaño y la invasión ganglionar axilar (AU)

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Importancia de la COX-2 en la regulación de la función hemodinámica y excretora renal

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Utilidad de la cuantificación y análisis visual de la captación de 99mTc-MIBI en el diagnóstico de lesiones mamarias / Usefulness of quantification and visual analysis of the uptake of 99m Tc-MIBI in the diagnosis of mammary lesions

Objetivo: Los estudios gammagráficos con 99mTc-MIBI en el diagnóstico no invasivo del cáncer de mama se encuentran ampliamente difundidos, y sus resultados corroborados por multitud de estudios. Sin embargo, la técnica gammagráfica tiene resultados erróneos, falsos positivos y negativos. El objetivo de este estudio es comprobar en que medida las diferentes características de la captación de 99mTc-MIBI, intensidad, tamaño, morfología etc., pueden ayudar a aumentar la sensibilidad y especificidad de la gammagrafía mamaria.Material y métodos: Estudiamos 201 pacientes (84 carcinomas mamarios y 117 lesiones benignas). A todas ellas se les realizó gammagrafía mamaria con 99mTc-MIBI y estudio anatomopatológico. A las lesiones que presentaron captación del radiofármaco se les realizó un estudio semicuantitativo (mediante índices T/F) y visual de dicha captación. Resultados: Del estudio de las 201 pacientes se obtuvieron 11 resultados falsos positivos, y 8 resultados falsos negativos. El análisis de los índices T/F mostró que no había diferencias estadísticamente significativas entre lesiones benignas y malignas (p>0,05). Existe una correlación estadísticamente significativa (p<0,05)entre la morfología de la captación del trazador y un determinado diagnóstico A.P. y entre la localización de la lesión en un cuadrante mamario y la intensidad de la captación.Conclusiones: La cuantificación mediante índices T/F de la captación de 99mTc-MIBI no aporta datos concluyentes acerca de la malignidad de las lesiones, sin embargo, un análisis más detallado de las características de la captación de trazador, nos permitirá aproximarnos más al diagnóstico correcto, disminuyendo el número de falsos positivos y negativos de la técnica. (AU)

[Utility of 201Tl washout in syndrome X patients]. / Utilidad del washout del 201Tl en pacientes con síndrome X.

INTRODUCTION: The term Syndrome X defines a group of patients who present symptoms of typical angina pectoris, positive exercise test and normal coronaries in the arteriogram. This study aims to compare the results of 201Tl scan images and washout in Syndrome X patients. METHODS: 24 patients with typical angina and normal arteriogram and 30 normal controls were studied with 201Tl SPECT to evaluate uptake and washout. RESULTS: 201Tl perfusion defects were found in 3 out of 24 (12.5%) and washout defects in 22 out of 24 (91.6 %). There is a statistically significant reduction (0 < 0.05) in thallium uptake and washout in patients with syndrome X compared to the control group. In addition, patients with syndrome X had a higher thallium uptake at rest than during exercise compared to the healthy subjects. CONCLUSIONS: Analysis of the 201Tl washout and thallium uptake can provide addition information in the evaluation of patients with syndrome X since the visual assessment of the cardiac scintigraphy with 201Tl is of limited value. Alterations of the myocardial perfusion in patients with chest pain and normal coronaries can be detected non-invasively with a complete scintigraphic study.