Utilidad clínica de la corrección de atenuación con rayos X en los estudios SPECT de perfusión miocárdica / Clinical utility of attenuation correction with X-RAYS in myocardial perfusion SPECT studies

Objetivos. Comparar la tomogammagrafía (SPECT) de perfusión miocárdica con corrección de atenuaciónmediante rayos X con la evaluación conjunta delas imágenes no corregidas y los datos del gated en el manejo de la enfermedad arterial coronaria.Método. A 60 pacientes (p) se les realizó una SPECT deperfusión miocárdica esfuerzo/reposo-gated con correcciónde atenuación mediante una tomografía computarizada (TC)de baja resolución con una gammacámara híbrida y una cateterización cardíaca. Se evaluaron cualitativamente tres tipos de imágenes: esfuerzo/reposo no corregidas (NC), esfuerzo/ reposo no corregidas valoradas juntamente con el gated (NCG) y esfuerzo/reposo corregidas por atenuación y con correción de scatter (CA). Con el test de McNemar se analizaron las diferencias estadísticas en la exactitud diagnósticaentre cada tipo de imágenes; p < 0,05 se consideró estadísticamente significativa. Resultados. Catorce p no tenían lesiones significativas en las arterias coronarias (LNS), en los 46 p restantes se detectaron:29 lesiones en la descendente anterior, 26 en la coronaria derecha y 18 en la circunfleja. En el territorio de la coronaria derecha la exactitud diagnóstica fue significativamente mayor en lasimágenes CA que en las NC (p < 0,001) y que en las NCG(p < 0,01). En el grupo de LNS hubo diferencias significativas entre NC y CA (p < 0,02) y entre NCG y CA (p < 0,05). Conclusiones. La corrección de atenuación con rayos X en los estudios SPECT-gated de perfusión miocárdica mejora significativamente tanto la capacidad de los mismos para descartar la existencia de enfermedad coronaria, como la exactitud diagnóstica en el territorio de la coronaria derecha

Objective. We have compared the uncorrected images of SPECT myocardial perfusion plus gated data with corrected images with X-rays in the management of coronary artery disease. Methods. In 60 patients (p) a stress/rest-gated myocardial perfusion SPECT was performed with attenuation correction with a hybrid gammacamera. All patients underwent cardiac catheterization. 3 types of images were qualitatively evaluated: uncorrected stress/rest (NC), uncorrected stress/rest plus gated (NCG) and stress/rest corrected for attenuation with scatter correction (AC). McNemar’s test was used to analyze the statistical differences in assessing the diagnostic accuracy of each type of images; p < 0.05 was considered statistically significant. Results. Fourteen p did not have significant lesions in the coronary arteries (NSL), 46 p showed lesions in coronary arteries: 29 in anterior descending, 26 in right coronary and 18 in circumflex. In right coronary territory, diagnostic accuracy was significantly higher on AC than on NC images (p < 0.001) and on AC than on NCG images (p < 0.01). In NSL group there are significant differences between NC and AC (p < 0.02) and between NCG and AC (p < 0.05). Conclusions. Attenuation correction with X-rays significantly improves diagnostic accuracy of uncorrected images and uncorrected images plus gated

[Clinical utility of attenuation correction with X-rays in myocardial perfusion SPECT studies]. / Utilidad clínica de la corrección de atenuación con rayos X en los estudios SPECT de perfusión miocárdica.

OBJECTIVE: We have compared the uncorrected images of SPECT myocardial perfusion plus gated data with corrected images with X-rays in the management of coronary artery disease. METHODS: In 60 patients (p) a stress/rest-gated myocardial perfusion SPECT was performed with attenuation correction with a hybrid gammacamera. All patients underwent cardiac catheterization. 3 types of images were qualitatively evaluated: uncorrected stress/rest (NC), uncorrected stress/rest plus gated (NCG) and stress/rest corrected for attenuation with scatter correction (AC). McNemar's test was used to analyze the statistical differences in assessing the diagnostic accuracy of each type of images; p < 0.05 was considered statistically significant. RESULTS: Fourteen p did not have significant lesions in the coronary arteries (NSL), 46 p showed lesions in coronary arteries: 29 in anterior descending, 26 in right coronary and 18 in circumflex. In right coronary territory, diagnostic accuracy was significantly higher on AC than on NC images (p < 0.001) and on AC than on NCG images (p < 0.01). In NSL group there are significant differences between NC and AC (p < 0.02) and between NCG and AC (p < 0.05). CONCLUSIONS: Attenuation correction with X-rays significantly improves diagnostic accuracy of uncorrected images and uncorrected images plus gated.

Ionic dependence of the velocity of release of ATP from permeabilized cholinergic synaptic vesicles.

Evidence is provided to show that synaptic vesicles have an internal matrix. Suspensions of cholinergic synaptic vesicles isolated from the electric organ of Torpedo marmorata fish were permeabilized in solutions containing low concentrations of Na(+) or Ca(2+). The release of ATP from the vesicular matrix was 10 times more effective with Ca(2+) than with Na(+). We ascertained whether these two cations induced a different velocity of release of ATP from the matrix. The release of ATP was monitored with the chemiluminescent reaction of luciferin-luciferase. The light signal generated was the result of the kinetics of ATP release of the enzymatic reaction. To overcome the kinetics of the enzymatic reaction, the light records were deconvoluted. The actual kinetics of ATP release of vesicles containing Na(+) or Ca(2+) were coincident. To validate this result, comparison was made with ATP release from intact nerve terminals which were already deconvoluted. The results show that the real time course of release is longer than that obtained from synaptic vesicles. This was as expected given that the release of neurotransmitters is due to successive molecular steps of synaptic vesicle exocytosis.

[Neuroactivation of the Tower of Hanoi in patients with obsessive-compulsive disorder and healthy volunteers]. / Neuroactivación con torre de Hanoi en pacientes con trastorno obsesivo-compulsivo y voluntarios sanos.

UNLABELLED: The aim of the study was to evaluate changes in regional cerebral blood flow (rCBF) in obsessive-compulsive disorder (OCD) patients and healthy controls during performance of Tower of Hanoi (TOH) test (cognitive task). MATERIAL AND METHODS: We compared TOH test performance in 30 OCD patients and 30 individually matched healthy volunteers. Intelligence and anxiety measurements were taken into account for all participants. Within the patient group, factors such as duration and severity of symptoms and low mood were considered. rCBF was estimated through the uptake of 99mTc-hexamethylpropylamine-oxime (HMPAO) on single photon emission computerised tomography (SPECT). Regional values were quantified as ratios of cortical blood flow. RESULTS: OCD patients and volunteers differed significantly in terms of subjective anxiety during procedures. TOH test performance was significantly impaired in OCD patients when compared with matched controls. 2-tailed t tests for repeated measures suggested that there were overall significant differences (p = 0.039) between both groups (OCD patients and controls) confined to left caudate activation. There was increased activity after activation in control subjects, but not in OCD patients. No differences in other regions were observed. CONCLUSIONS: These results suggest a modification of the activating systems of basal ganglia functions in OCD compared with normal subjects.

Neuroactivación con torre de Hanoi en pacientes con trastorno obsesivo-compulsivo y voluntarios sanos / Neuroactivation of the tower of Hanoi in patients with obsessive-compulsive disorder and healthy volunteers

El objetivo de este estudio fue la evaluación de cambios en el flujo sanguíneo cerebral regional (FSCR) en pacientes trastorno obsesivo-compulsivo (TOC) y controles sanos durante la ejecución de la tarea cognitiva torre de Hanoi (TH).Material y método: Se comparó los resultados de la ejecución del test de la TH en 30 pacientes con TOC y una población comparable de voluntarios sanos. Se realizaron medidas psicológicas de la inteligencia y ansiedad a todos los sujetos del estudio. En el grupo de pacientes se evaluó además la severidad de los síntomas y la posible presencia de depresión. El FSCR se estimó mediante SPECT cerebral con hexamethylpropylamina-oxima (HMPAO). Los valores regionales se determinaron usando la actividad cortical como referencia. Resultados: Los pacientes y controles se diferenciaron significativamente en cuanto a la presencia de ansiedad. La ejecución de la prueba de la TH fue peor en los pacientes con TOC que en los controles. La prueba de la t de Student para medidas apareadas puso de manifiesto diferencias significativas (p = 0,039) entre pacientes y controles en cuanto a la activación del núcleo caudado izquierdo. Los controles activaron dicho núcleo durante la ejecución de la TH y los pacientes no. No aparecieron diferencias en otras regiones cerebrales. Conclusión: Estos resultados sugieren una modificación en los sistemas de activación de los ganglios basales en pacientes con TOC comparados con controles (AU)

[Study of renal transplant by deconvoluted renogram with 99m Tc-mercaptoacetyltriglycine (Mag3)]. / Estudio de la evolución del trasplante renal mediante la deconvolución del renograma con 99m Tc-mercapto-acetil-triglicina (Mag-3).

AIM: To evaluate the usefulness of the 99mTc-MAG3 renogram deconvolution and its derived parameters in kidney graft function monitoring. MATERIAL AND METHOD: 221 renograms were studied: 64 were diagnosed as functioning graft (FG), 37 as functioning graft with elevated serum creatinine (FG2), 59 as acute tubular necrosis (ATN), 30 as acute rejection (AR), 20 as urinary tract obstruction (OBS) and 11 as cyclosporine nephrotoxicity (TNX). The parameters evaluated were: maximal activity of conventional renogram and mean transit time (MTT), time to reach 20% (T20) and 80% (T80) of the height of the RRF and initial uptake (IU) from the deconvoluted renal retention function (RRF). RESULTS: MTT and T20 were significantly longer and IU significantly lower in non-functioning grafts. However, MTT and T20 became shorter than in FG when graft function is severely impaired. CONCLUSION: IU, MTT and T20 are more useful than maxim activity of renogram in monitoring kidney graft function and in evaluating renal dysfunction severity. IU is a very sensitive and early parameter.

Estudio de la evolución del trasplante renal mediante la deconvolución del renograma con 99mTc-mercapto-acetil-triglicina (Mag-3) / Study of renal transplant by deconvoluted renogram with 99mtc-mercaptoacetyltriglycine (mag3)

Objetivo: Evaluar la utilidad de los parámetros obtenidos a partir de la deconvolución del renograma con 99mTc-MAG3 en la monitorización de la función de los injertos renales. Material y método: Se ha estudiado 221 renogramas con el siguiente diagnóstico: 64 injerto funcionante (IF), 37 injerto funcionante con creatinina elevada (IF2); 59 necrosis tubular aguda (NTA), 30 rechazo agudo (RA); 20 obstrucción de vías urinarias (OBS) y 11 nefrotoxicidad (NTX). Los parámetros estudiados han sido: 1) del renograma: la actividad máxima y 2) de la función de retención renal (FRR): tiempo de tránsito medio (TTM), tiempo de caída del 20 por ciento (T20) y del 80 por ciento (T80) de la FRR y captación inicial (CI). Resultados: El TTM y el T20 han sido significativamente más largos y la CI significativamente menor en los injertos no funcionantes. Sin embargo, el TTM y el T20 se acortan más que en el IF cuando la función está severamente afectada. Conclusiones: La CI, TTM y T20 son más útiles que la actividad máxima del renograma en la monitorización del injerto renal y en la valoración de la severidad de la afectación funcional del mismo. La CI parece ser el parámetro más precoz y sensible (AU)

Validation of the preparation of individual doses of (131)I-sodium o-iodohippurate ((131)I-hippuran).

The preparation of low activity doses of (131)I-hippuran has a drawback due to its high radioactivity concentration. In this study we diluted the radiopharmaceutical with saline or phosphate buffered saline (PBS) in order to decrease the radioactivity concentration, facilitate the preparation of individual doses and validate these procedures. We prepared doses of approx. 1.85 MBq of (131)I-hippuran from 10 different batches the day before the calibration date: undiluted, and diluted 1:9 with saline or PBS. The radiochemical purity (RCP) was evaluated the day after the expiration date. The percentage of (131)I-hippuran retained on syringes was assessed in vitro, after emptying the syringe and washing it twice with water (n=3 x 27); and in vivo, after the endovenous administration of the dose and washing the syringe twice with the patient's blood (n=3 x 75). Sterility was assessed using fluid thyoglicolate medium (n=3 x 15). All RCP values were greater than those required by the European Pharmacopoeia (>96%) except one of the undiluted (131)I-hippuran (95.8%) doses. No statistical difference was observed among them. The mean undiluted (131)I-hippuran retained in vitro was 5.4% (SD=6.5%), statistically greater (P<0.01) than both saline diluted (mean=1.5%, SD=1.1%) and PBS diluted (mean=2.0%, SD=2.4%). The mean undiluted (131)I-hippuran retained in vivo was 6.4% (SD=5.4%), statistically greater (P<10-5) than both saline diluted (mean=3.1%, SD=2.3%) and PBS diluted (mean=3.1%, SD=3.1%). We concluded that: (1) the dilution of (131)I-hippuran with saline or PBS makes both the preparation of individual doses and its administration to the patient easier without decreasing its radiopharmaceutical quality; and (2) using saline or PBS diluted (131)I-hippuran the percentage of radiopharmaceutical retained on the syringes, after use, is minimized.

[Tomographic studies of myocardial perfusion normality with 99m Tc-Tetrofosmin. Spanish multicenter study]. / Estudios tomográficos de normalidad de perfusión miocárdica con 99mTc-Tetrofosmina. Estudio multicéntrico español (I). Aspectos técnicos: diseño del estudio y control de calidad.

As a first phase in a nationwide multicenter study to obtain myocardial perfusion normality patterns, this work presents the study design and quality control methodology used to guarantee that the gammacameras fulfilled some minimum quality requirements. The following aspects were considered in the study design in order to guarantee the homogeneity and interchangeability of the results: creation and structure of the work group, data interchange system, data selection and acquisition, centralized archiving and processing, assessment system, study acceptance criteria and distribution of the results. To carry out the instrumental quality control, three phantom studies were established, one to control the rotation center, another to verify tomographic uniformity and a third to simulate the shape and orientation of the left ventricle. The three phantoms circulated through all of the 18 participating centers in this project, which corresponded to 19 gammacameras. Very strict guidelines had to be followed in the acquisition and processing of these phantom studies. If any camera and/or center did not fulfill the criteria established, it was advised of the problem detected in order to correct it. Once the defect was repaired, all the phantoms were sent again for verification. Uniformity of the rotation center was quantified by means of the eccentricity of a 360 degrees orbit, admitting up to a maximum of 10%. Tomographic uniformity was visually assessed, taking in account the number of slices with rings and their contrast and finally no artifacts could be present in the reconstructed study of the ventricle. The center of rotation was within limits in all the cameras except one case while the tomographic uniformity was incorrect in 6 cases. All the departments, except one, corrected the defects detected, and passed the acceptance test. The results made it possible to guarantee adequate homogeneity and instrumental quality in this multicenter study.

[Tomographic studies of myocardial perfusion normality with 99m Tc-Tetrofosmin. Spanish multicenter study]. / Estudios tomográficos de normalidad de perfusión miocárdica con 99mTc-Tetrofosmina. Estudio multicéntrico español (II). Aspectos clínicos.

This objective of this study was to obtain a pool of Myocardial Perfusion SPECTs with a 99mTetrofosmin stress/rest one day protocol in normal volunteers having a less than or equal to 5% likelihood of coronary artery disease that represents normalcy in the Spanish population. A total of 169 volunteers from 15 hospitals were studied. The volunteers were divided into 5 groups: Groups 1, 2 or 3 corresponding to men < 30 years (n = 33), men between 30 and 50 years (n = 32), or men > 50 years (n = 31); Groups 4 or 5: premenopausal (n = 38) or postmenopausal women (n = 35). A clinical history, physical examination, clinical laboratory parameters, echocardiography and a symptom limited exercise stress test were performed in all of them and had to be normal. The mean likelihood of coronary artery disease was 1.15 +/- 1.07%.Twenty-four segments were analyzed in each study and were classified into 5 grades of uptake (1 = normal, 2, 3, 4 = mild, moderate or severe defect and 5 = no uptake). Defects were then analyzed according to sex and location. Considering the stress and rest studies separately (8,112 segments), only 19 moderate and 75 mild defects were found, these corresponding to 16 volunteers, with more inferior defects in men and anterior defects in women. These data validate the normalcy of our population. A pool of Myocardial Perfusion SPECTs with a 99mTetrofosmin stress/rest one day protocol in normal volunteers that represents Spanish normal values was obtained.

Estudios tomográficos de normalidad de perfusión miocárdica con 99m Tc-Tetrofosmina. Estudio multicéntrico español (I). Aspectos técnicos: diseño del estudio y control de calidad / Tomographic studies of myocardial perfusion normality with 99mtc-tetrofosmin. spanish multicenter study (i). technical aspects: study design and quality control

Como primera fase de un estudio multicéntrico para la obtención de patrones de normalidad de perfusión miocárdica, en este trabajo se presenta el diseño del estudio y la metodología de control de calidad empleada para garantizar que las gammacámaras cumplieran con unos requisitos mínimos de calidad. En el diseño del estudio se han considerado los siguientes aspectos a fin de garantizar la homogeneidad e intercambiabilidad de resultados: creación y estructuración de un grupo de trabajo, sistema para el intercambio de datos, selección y adquisición de datos, registro y procesado centralizado de los estudios, sistema de valoración y criterios de aceptación de los estudios y la distribución de resultados. Para el control de calidad de la instrumentación se construyeron tres maniquíes, uno para el control del centro de rotación, otro para la comprobación de la uniformidad tomográfica y un tercero que simulaba la forma y posición del ventrículo izquierdo. Los tres maniquíes circularon por todos los centros participantes en este proyecto (18) que correspondían a 19 cámaras, debiendo seguir unas normas estrictas para su utilización. Si algún equipo no cumplía con los criterios establecidos el centro correspondiente era avisado del problema detectado para que procediera a su rectificación. Un vez reparado el defecto se volvía a enviar el conjunto de maniquíes para su verificación. La constancia del centro de rotación se cuantificó midiendo la excentricidad de la órbita, admitiéndose hasta un máximo de 10 por ciento. La uniformidad tomográfica se valoró visualmente teniendo en cuenta tanto el número de cortes con presencia de anillos como su contraste. En las imágenes del maniquí de ventrículo se comprobó la ausencia de artefactos. El centro de rotación fue correcto en todas las gammacámaras excepto en una mientras que la uniformidad tomográfica presento defectos en 6 casos. El maniquí de ventrículo fue siempre correcto. Todos los centros, excepto uno, corrigieron los defectos detectados por lo que pasaron la prueba de aceptación. Los resultados permitieron garantizar la adecuada homogeneidad y calidad instrumental de los estudios generados en este estudio multicéntrico. (AU)

Estudios tomográficos de normalidad de perfusión miocárdica con 99m Tc-Tetrofosmina. Estudio multicéntrico español (II). Aspectos clínicos / Tomographic studies of myocardial perfusion normality with 99mtc-tetrofosmin. spanish multicenter study (ii). clinical aspects

El objetivo fue obtener un número suficiente de Tomogammagrafías Miocárdicas de Perfusión en voluntarios presumiblemente normales, con una probabilidad pretest de padecer enfermedad coronaria menor del 5 por ciento, siguiendo un protocolo corto esfuerzo/reposo con 99mTc-Tetrofosmina, con el fin de constituir un conjunto de estudios de normalidad representativo de la población española. Se estudiaron 169 voluntarios, pertenecientes a 15 centros, divididos en 5 grupos: Grupos 1, 2 y 3 correspondiendo a: varones menores de 30 años (n = 33), entre 30 y 50 años (n = 32) o mayores de 50 años (n = 31); Grupos 4 y 5: mujeres premenopáusicas (n = 38) o postmenopáusicas (n = 35). A todos ellos se les historió y realizó examen físico completo, analítica general, ecocardiografía y prueba de esfuerzo máxima limitada por síntomas, que debieron ser normales. El promedio de la probabilidad pretest de padecer enfermedad coronaria fue de 1,15 ñ 1,07 por ciento. En cada tomogammagrafía se analizaron 24 segmentos que se clasificaron según su captación (1 = normal, 2, 3, 4 = defecto ligero, moderado o severo y 5 = captación nula). Posteriormente, los defectos se agruparon en función del sexo y de su localización. Considerando los estudios en esfuerzo y en reposo (8.112 segmentos), se encontraron únicamente 19 defectos moderados y 75 ligeros, que correspondían a 16 individuos, lo que apoya la 'normalidad' de la muestra estudiada, con una mayor frecuencia de defectos en la pared miocárdica inferior en hombres y anterior en mujeres. Se constituyó un conjunto de estudios de normalidad de Tomogammagrafías miocárdicas de perfusión, siguiendo un protocolo corto esfuerzo/reposo con 99mTc-Tetrofosmina, representativo de la población española (AU)

Blood volumes and renal function in overt and subclinical primary hypothyroidism.

INTRODUCTION: Thyroid dysfunction is associated with marked alterations in cardiovascular and renal functions. In hypothyroidism, myocardial contractility, cardiac output, and oxygen consumption are decreased, whereas peripheral resistance is increased. METHODS: We assessed blood volumes and effective renal plasma blood flow (ERPF) and glomerular filtration rate (GFR) in 17 patients with overt primary hypothyroidism and in 15 of these patients when in euthyroid state after substitutive therapy. We performed the same measurements in eight patients with subclinical hypothyroidism. RESULTS: In the hypothyroid state, the plasma volume measured by dilution of 125I-albumin (APV) was higher than the calculated plasma volume (CPV) from packed red cell mass, suggesting an extravascular escape of albumin. After substitutive therapy, the CPV showed a statistical increase (P < 0.05), whereas APV remained unchanged. Both ERPF and GFR increased after thyroxine therapy (p < 0.05). In the subclinical group, blood volumes and renal function were similar to those found in the other group of patients when in the euthyroid state. CONCLUSIONS: We conclude that in primary hypothyroidism, ERPF and GFR are low, but that these values improve with substitutive therapy. CPV is a better index of the current plasma volume than APV. The difference between these two parameters suggests that the escape of albumin into the extravascular space in primary hypothyroidism is terminated by treatment. There are no clear abnormalities either in blood volumes or in renal function in subclinical hypothyroidism.

[Quantification of liver volume by SPECT]. / Cuantificación del volumen hepático por SPECT.

This study aimed to optimize a method to estimate liver volume by SPECT. Several phantoms were used to simulate the liver shape with a volume between 400 and 2,500 cc. The SPECT studies were acquired using 360 degrees and 180 degrees circular orbits, 64 projections, 64 x 64 word matrix, all purpose parallel-hole collimator and were reconstructed with a HANN filter with frequency cutoff = 0.5 cycles/ pixel. The reconstructed studies were processed with a program that estimates the organ volume for different threshold cutoff levels for counting. The optimum cutoff threshold level to quantify the liver volume was 50% and 48% for 360 degrees orbits and 180 degrees orbits, respectively. A linear relationship was observed between the real and calculated volumes with r = 0.994 for the 360% orbits and r = 0.976 for the 180 degrees orbits, The average error between corrected and real volumes was 4.2% and 10.87% for both orbits, respectively. The method was applied to 14 patients with different degrees of hepatomegaly who had undergone a liver 99mTc-sulfur colloid scintigraphy. The intra and interobserver variability as well as the influence of the degree of contour adjustment of the phantom mask were studied. No significant differences were observed in the results, so that it can be considered that neither the mask trace nor the operator influence the results.

[Effective renal plasma flow with I-131-hipuran: evaluation of a method with four extractions]. / Flujo plasmático renal efectivo con I-131-hipuran: evalución de un método con cuatro extracciones.

The aim of this work was to evaluate a method for the estimation of the effective renal plasma flow (ERPF) using sodium 131I-o-hippurate (OIH) by means the bicompartmental analysis of the radioactive concentration of 4 plasma samples, analyzing the error obtained respecting to the multi-sample method and comparing it with those obtained with other simplified methods. We calculated the ERPF from 62 patients using the multi-sample method as standard, the method based in a single sample at 44 minutes p.i., a method based in 2 samples from the first exponential, 4 methods based in 2 samples from the second exponential, one method based in 3 samples and 5 methods based in 4 samples (2 from the first exponential and 2 from the second exponential). Each simplified method was compared to the standard method and their absolute error (AE) and standard estimation error (SEE) were calculated. The method based in the 4 samples withdrawn at 4, 10, 30 and 60 minutes p.i. was the best of them with a correlation factor with the standard equal to 0.997, an EA that ranged from -63 ml/min to 49 ml/min (mean: -4 ml/min) and a SEE of 19.5 ml/min.

[Classification of kidney grafts by renographic parameters]. / Clasificación de injertos renales mediante parámetros renográficos.

The aim of this work was to analyze the use of some renographic parameters derived from the 99mTc-MAG3 renogram to classify post-transplantion studies in two groups: Normal functioning grafts (NFG) and delayed grafts function (DGF) which included Acute Tubular Necrosis (ATN) and Acute Rejection (AR). The analysis included data from 38 NFG, 33 ATN and 23 AR. The parameters calculated were: mean transit time (MTT), the Initial Uptake (IU) and the maximum activity (MA) of the renogram. The results obtained from this analysis show that ln(IU) is the best parameter to classify individuals in either group and that the use of MA or the MTT does not improve the results. Using a cutoff point of ln(IU) = 0.28 and a prevalence of 25% for DGF, the estimated predictive values were 92% for DGF and 99% for NFG.

MAG3 renogram deconvolution in kidney transplantation: utility of the measurement of initial tracer uptake.

UNLABELLED: The study of renal retention function by deconvolution analysis of renographic curves is useful to calculate quantitative parameters in renal studies. The aim of the work is to evaluate the usefulness of 99mTc-MAG3 renogram deconvolution in renal function monitoring of kidney graft recipients. METHODS: Forty-three kidney grafts and 112 renograms were studied: 41 were diagnosed as functioning graft, 35 as acute tubular necrosis, 24 as acute rejection, 8 as obstruction and 4 as cyclosporin toxicity. The parameters calculated were mean transit time (MTT), time at 20% of renal retention function (T20) and initial uptake (IU). RESULTS: MTT and T20 were significantly longer in obstructives than in functioning grafts (p < 0.001). Initial uptake was significantly lower in acute tubular necrosis (ATN) and acute rejection (p < 0.001) and in obstructives (p < 0.05) than in functioning grafts. The joint evaluation of MTT and IU allowed to diagnose cases with graft function severely impaired. CONCLUSION: Initial uptake is useful in evaluating post-transplantation complications and in combination with MTT and T20 reflects renal dysfunction severity.

Evaluation of renographic and metabolic parameters in human kidney transplantation.

BACKGROUND: The aim of this work is to demonstrate that the value of the mean transit time (MTT) obtained from the 99mTc-MAG3 renogram deconvolution is related to the levels of adenine nucleotides determined in cortical biopsies from transplanted kidneys. METHODS: The functional state was estimated by means of the MTT and the initial height (H0) of the renal retention function obtained from the 99mTc-MAG3 renogram deconvolution and by the measure of adenine nucleotides obtained from biopsies. We studied 30 kidney graft recipients, 25 normal functioning grafts (NFG) and 5 with acute tubular necrosis (ATN). RESULTS: The MTT is significantly longer for ATN (p < 0.001). The initial uptake values (H0) are significantly lower for ATN (p < 0.001). The sum of adenine nucleotides (SAN) is significantly greater for NFG than for ATN (p < 0.001). The values of the MTT seem to reflect the energy state of the cells in transplanted kidney. CONCLUSION: The analysis of MTT may be indicative of the functional metabolic recovery and thus it may be predictive of the renal graft function at least in the same extent than the biochemical analysis of a cortical renal biopsy immediately after blood reperfusion of the tissue.