18F-FDG PET/TC con contraste intravenoso en el seguimiento estandarizado de pacientes con linfoma / 18F-FDG PET/contrast enhanced CT in the standard follow-up of patients with lymphoma

Objetivo. Valorar la capacidad diagnóstica de la 18F-FDG PET/TC con contraste intravenoso (PET/TCciv) en la detección de recidivas asintomáticas de pacientes con linfoma. Material y métodos. Se realizó una PET/TCciv en pacientes con linfoma para seguimiento estandarizado y en remisión completa clínica. Tanto la 18F-FDG PET como la TCciv fueron evaluadas de forma independiente por 2 observadores y clasificadas como positiva o negativa para recurrencia. Adicionalmente se realizó una valoración combinada de ambas exploraciones. El diagnóstico final se estableció por análisis histopatológico o seguimiento clínico superior a 6 meses. Se calcularon los parámetros diagnósticos estadísticos y los niveles de concordancia entre ambas técnicas diagnósticas. Resultados. Se analizaron un total de 114 exploraciones pertenecientes a 90 pacientes. Solo 4 pacientes fueron diagnosticados de recurrencia asintomática durante el seguimiento. La 18F-FDG PET/TCciv, la 18F-FDG PET y la TCciv mostraron asociación con el diagnóstico final (p=0,002 y χ2=11,96; p<0,001 y χ2=15,60; p=0,001 y χ2=11,96, respectivamente). La concordancia entre la 18F-FDG PET y la TCciv fue moderada/alta y significativa (kappa=0,672; p<0,001). Se obtuvo una sensibilidad y especificidad del 50 y 88% para la 18F-FDG PET/TCciv, del 50 y 93% para la 18F-FDG PET y del 50 y 91% para la TCciv. Conclusión. El uso combinado de la 18F-FDG PET/TCciv no ofreció ventaja con respecto a ambas técnicas por separado en la detección de recidiva asintomática por linfoma

Aim. To assess the diagnostic accuracy of 18F-FDG PET/contrast enhanced computed tomography (ceCT) in the detection of asymptomatic recurrences in patients with lymphoma. Material and methods. Patients with lymphoma and clinical complete remission underwent 18F-FDG PET/ceCT for standard follow-up.18F-FDG PET and ceCT were evaluated blindly by two independent observers, and classified as positive or negative for recurrence. Additionally a combined evaluation of both techniques was performed. The final diagnosis was established by histopathological analysis or a clinical follow-up longer than 6 months. Statistical diagnostic parameters and concordance levels between both diagnostic techniques were calculated. Results. A total of 114 explorations on 90 patients were analyzed. Only 4 patients were diagnosed as asymptomatic recurrence during the follow-up. 18F-FDG PET/ceCT, 18F-FDG PET and ceCT showed an association with the final diagnosis (p=0.002 and χ2=11.96; p<0.001 and χ2=15.60; p=0.001 and χ2=11.96, respectively). The concordance between 18F-FDG PET and ceCT was moderate/high and significant (kappa=0.672; p<0.001). A sensitivity and specificity of 50% and 88% was obtained for the 18F-FDG PET/ceCT civ, 50% and 93% for the 18F-FDG PET, and 50% and 91% for the ceCT. Conclusion. The combined use of 18F-FDG PET/ceCT did not offer any advantage compared to any isolated diagnostic technique in the detection of asymptomatic lymphoma recurrence

18F-FDG PET/contrast enhanced CT in the standard follow-up of patients with lymphoma. / 18F-FDG PET/TC con contraste intravenoso en el seguimiento estandarizado de pacientes con linfoma.

AIM: To assess the diagnostic accuracy of 18F-FDG PET/contrast enhanced computed tomography (ceCT) in the detection of asymptomatic recurrences in patients with lymphoma. MATERIAL AND METHODS: Patients with lymphoma and clinical complete remission underwent 18F-FDG PET/ceCT for standard follow-up.18F-FDG PET and ceCT were evaluated blindly by two independent observers, and classified as positive or negative for recurrence. Additionally a combined evaluation of both techniques was performed. The final diagnosis was established by histopathological analysis or a clinical follow-up longer than 6 months. Statistical diagnostic parameters and concordance levels between both diagnostic techniques were calculated. RESULTS: A total of 114 explorations on 90 patients were analyzed. Only 4 patients were diagnosed as asymptomatic recurrence during the follow-up. 18F-FDG PET/ceCT, 18F-FDG PET and ceCT showed an association with the final diagnosis (p=0.002 and χ2=11.96; p<0.001 and χ2=15.60; p=0.001 and χ2=11.96, respectively). The concordance between 18F-FDG PET and ceCT was moderate/high and significant (kappa=0.672; p<0.001). A sensitivity and specificity of 50% and 88% was obtained for the 18F-FDG PET/ceCT civ, 50% and 93% for the 18F-FDG PET, and 50% and 91% for the ceCT. CONCLUSION: The combined use of 18F-FDG PET/ceCT did not offer any advantage compared to any isolated diagnostic technique in the detection of asymptomatic lymphoma recurrence.

Basal 18F-FDG PET/CT in follicular lymphoma: a comparison of metabolic and clinical variables in the prognostic assessment / Valor de la 18F-FDG PET/TC basal en el linfoma folicular: comparación de las variables metabólicas y clínicas en la valoración pronóstica

Aim. To analyze the relationship of clinical variables related to prognosis and tumor burden, with metabolic variables obtained in the staging 18F-FDG PET/CT, and their value in the prognosis in follicular lymphoma (FL). Methods. 82 patients with FL, a 18F-FDG PET/CT at diagnosis and a follow-up for a minimum of 12 months, were retrospectively enrolled in the present study. Clinical variables (Tumor grade, Follicular Lymphoma International Prognostic Index (FLIPI) and Tumor burden) were evaluated. Metabolic variables such as SUVmax in the highest hypermetabolic lesion, extralymphatic locations, number of involved lymph node locations, bone marrow (BM) involvement, PET stage and diameter of the biggest hypermetabolic lesion, were analyzed in order to establish a PET score and classify the studies in low, intermediate and high metabolic risk. Clinical and metabolic variables (included metabolic risk) were compared. The relation among all variables and disease-free survival (DFS) was studied. Results. The 28% of patients had a high-grade tumor. The 30.5% had FLIPI risk low, 29.3% intermediate y 40.2% high. The 42.7% presented a high tumor burden. The PET/CT was positive in 94% of patients. The tumor grade did not show significant relation with metabolic variable. FLIPI risk and tumor burden showed statistical relations with the SUV max and the PET score (p<0.008 and p=0.003 respectively). With respect to DFS, significant differences were detected for the PET stage and FLIPI risk (p=0.015 and p=0.047 respectively). FLIPI risk was the only significant predictor in Cox regression analysis, with a Hazard Ratio of 5.13 between high risk and low risk. Conclusion. The present research highlights the significant relation between metabolic variables obtained with FDG PET/CT and clinical variables although their goal as an independent factor of prognosis was not demonstrated in the present work (AU)

Objetivo. Analizar la relación entre las variables clínicas relativas al pronóstico y la carga tumoral y las variables obtenidas en la 18F-FDG PET/TC de estadificación, así como su valor pronóstico para el linfoma folicular (LF). Métodos. Se realizó un estudio retrospectivo de 82 pacientes con LF, 18F-FDG PET/TC en el momento del diagnóstico y seguimiento mínimo de 12 meses. Se evaluaron las variables clínicas (grado tumoral, Índice pronóstico internacional para el linfoma folicular (FLIPI) y carga tumoral). Se analizaron las variables metabólicas tales como SUVmax en las lesiones más hipermetabólicas, localizaciones extralinfáticas, número de localizaciones ganglionares afectas, afectación de la médula ósea, estadio PET y diámetro de la lesión hipermetabólica de mayor tamaño, a fin de establecer una puntuación PET y clasificar los estudios en riesgo bajo, medio y elevado. Se compararon las variables clínicas y metabólicas (incluyendo el riesgo metabólico) y se estudió la relación entre todas las variables y la supervivencia libre de enfermedad (SLE). Resultados. El 28% de los pacientes tenían un tumor de alto grado. El 30,5% tenía un riesgo bajo de FLIPI, el 29,3% un grado intermedio y el 40,2% un riesgo elevado. El 42,7% presentó una elevada carga tumoral. La PET/TC fue positiva en el 94% de los pacientes. El grado del tumor no reflejó una relación significativa con la variable metabólica. El riesgo de FLIPI y la carga tumoral guardaron relaciones estadísticas con SUVmax y la puntuación PET (p<0,008 y p=0,003, respectivamente). Con respecto a la SLE, se detectaron diferencias significativas para el estadio PET y el riesgo FLIPI (p=0,015 y p=0,047, respectivamente). El riesgo FLIPI fue el único factor predictivo significativo en el análisis de regresión, con un cociente de riesgo instantáneo (HR) de 5,13 entre alto y bajo riesgo. Conclusión. La presente investigación resalta la considerable relación entre las variables metabólicas obtenidas con FDG PET/TC y las variables clínicas, aunque su objetivo como factor independiente de pronóstico no ha sido demostrado en el presente estudio (AU)

Basal (18)F-FDG PET/CT in follicular lymphoma: A comparison of metabolic and clinical variables in the prognostic assessment.

AIM: To analyze the relationship of clinical variables related to prognosis and tumor burden, with metabolic variables obtained in the staging (18)F-FDG PET/CT, and their value in the prognosis in follicular lymphoma (FL). METHODS: 82 patients with FL, a (18)F-FDG PET/CT at diagnosis and a follow-up for a minimum of 12 months, were retrospectively enrolled in the present study. Clinical variables (Tumor grade, Follicular Lymphoma International Prognostic Index (FLIPI) and Tumor burden) were evaluated. Metabolic variables such as SUVmax in the highest hypermetabolic lesion, extralymphatic locations, number of involved lymph node locations, bone marrow (BM) involvement, PET stage and diameter of the biggest hypermetabolic lesion, were analyzed in order to establish a PET score and classify the studies in low, intermediate and high metabolic risk. Clinical and metabolic variables (included metabolic risk) were compared. The relation among all variables and disease-free survival (DFS) was studied. RESULTS: The 28% of patients had a high-grade tumor. The 30.5% had FLIPI risk low, 29.3% intermediate y 40.2% high. The 42.7% presented a high tumor burden. The PET/CT was positive in 94% of patients. The tumor grade did not show significant relation with metabolic variable. FLIPI risk and tumor burden showed statistical relations with the SUV max and the PET score (p<0.008 and p=0.003 respectively). With respect to DFS, significant differences were detected for the PET stage and FLIPI risk (p=0.015 and p=0.047 respectively). FLIPI risk was the only significant predictor in Cox regression analysis, with a Hazard Ratio of 5.13 between high risk and low risk. CONCLUSION: The present research highlights the significant relation between metabolic variables obtained with FDG PET/CT and clinical variables although their goal as an independent factor of prognosis was not demonstrated in the present work.

Evaluación cuantitativa y cualitativa de la PET/TC a mitad del tratamiento en linfomas en la predicción de respuesta metabólica completa / Quantitative and qualitative evaluation of the interim PET/CT in lymphoma treatment in the prediction of complete metabolic response

Objetivo. Realizar una comparación entre 2 métodos para la valoración de la PET/TC a la mitad del tratamiento (PET/TC-mt) en linfomas, y establecer cuál de ellos predice con mayor precisión una respuesta metabólica completa (RMC) en la PET/TC al final del tratamiento (PET/TC-ft). Material y métodos. Análisis retrospectivo longitudinal de los estudios PET/TC de estadificación (PET/TC-e), PET/TC-mt y PET/TC-ft de 65 pacientes con linfoma, 35 linfoma de Hodgkin y 30 linfoma no Hodgkin. La PET/TC-mt fue realizada entre el segundo y cuarto ciclo de quimioterapia y se valoró utilizando 2 criterios de interpretación: criterio cualitativo (escala visual de 5 puntos), criterio semicuantitativo (porcentaje de diferencia entre el SUVmax de la lesión con mayor actividad metabólica en la PET/TC-e y la PET/TC-mt). Analizamos la probabilidad de obtener una RMC en la PET/TC-ft según la clasificación de la PET/TC-mt con estos 2 criterios. Resultados. Obtuvimos valores de sensibilidad (S), especificidad (E), valor predictivo positivo (VPP), valor predictivo negativo (VPN) y razón de probabilidad (RP) para el método cualitativo/semicuantitativo de 91/80%, 76,2/67%, 88,9/83,3%, 80/60,9% y 32/7,8% respectivamente, para predecir un RMC en la PET/TC-ft. No encontramos diferencias estadísticamente significativas entre la RP del análisis cualitativo y semicuantitativo (p=0,1942). Conclusión. Encontramos claras diferencias en la S, E, VPP y VPN entre ambos métodos de valoración de la PET/TC-mt para predecir una RMC en la PET/TC-ft. Sin embargo, al no encontrar diferencias estadísticamente significativas en la RP, no podemos afirmar que el método cualitativo sea superior al semicuantitativo para este fin (AU)

Objective. To compare two different methods for the interpretation of interim PET/CT (PET/CT-i) in lymphomas, and to establish which one best predicts a complete metabolic response (CMR) in the PET/CT study at the end of treatment (PET/CT-et). Material and Methods. Retrospective longitudinal analysis of the PET/CT studies for staging (PET/CT-s), PET/CT-i and PET/CT-et of 65 patients, 35 Hodgkin's lymphoma (HL) and 30 Non-HL. The PET/CT-i was performed between the second and fourth chemotherapy cycle. It was interpreted using two different criteria: qualitative criteria (5 point visual scale), semiquantitative criteria (percentage difference between the lesion with more SUVmax in the PET/CT-s and PET/CT-i). We analyzed the likelihood of obtaining a CMR in the PET/CT-et according to the results obtained on the PET/CT-i with these two criteria. Results. We obtained sensitivity (S), specificity (Sp), positive predictive values (PPV), negative predictive values (NPV) and likelihood ratio (LR) for the qualitative/semiquantitative method of 91%/80%, 76.2%/67%, 88.9%/83.3%, 80%/60.9% and 32%/7.8%, respectively, to predict a CMR in the PET/CT-et. There were no statistically significant differences between the LR of both methods (p=0.1942). Conclusion. We found clear differences in S, Sp, PPV and NPV between both interpretation criteria for the PET/CT-i to predict a CMR in the PET/CT-et. Nevertheless, we cannot confirm the superiority of the qualitative method over the semiqualitative method for this purpose as no statistically significance differences were found in their LR in our study (AU)

[Quantitative and qualitative evaluation of the interim PET/CT in lymphoma treatment in the prediction of complete metabolic response]. / Evaluación cuantitativa y cualitativa de la PET/TC a mitad del tratamiento en linfomas en la predicción de respuesta metabólica completa.

OBJECTIVE: To compare two different methods for the interpretation of interim PET/CT (PET/CT-i) in lymphomas, and to establish which one best predicts a complete metabolic response (CMR) in the PET/CT study at the end of treatment (PET/CT-et). MATERIAL AND METHODS: Retrospective longitudinal analysis of the PET/CT studies for staging (PET/CT-s), PET/CT-i and PET/CT-et of 65 patients, 35 Hodgkin's lymphoma (HL) and 30 Non-HL. The PET/CT-i was performed between the second and fourth chemotherapy cycle. It was interpreted using two different criteria: qualitative criteria (5 point visual scale), semiquantitative criteria (percentage difference between the lesion with more SUVmax in the PET/CT-s and PET/CT-i). We analyzed the likelihood of obtaining a CMR in the PET/CT-et according to the results obtained on the PET/CT-i with these two criteria. RESULTS: We obtained sensitivity (S), specificity (Sp), positive predictive values (PPV), negative predictive values (NPV) and likelihood ratio (LR) for the qualitative/semiquantitative method of 91%/80%, 76.2%/67%, 88.9%/83.3%, 80%/60.9% and 32%/7.8%, respectively, to predict a CMR in the PET/CT-et. There were no statistically significant differences between the LR of both methods (p=0.1942). CONCLUSION: We found clear differences in S, Sp, PPV and NPV between both interpretation criteria for the PET/CT-i to predict a CMR in the PET/CT-et. Nevertheless, we cannot confirm the superiority of the qualitative method over the semiqualitative method for this purpose as no statistically significance differences were found in their LR in our study.

PET-TAC con 18F-FDG en el seguimiento de pacientes con linfoma: detección de recidivas asintomáticas / 18 F-FDG-PET/CT in the surveillance of patients with lymphoma: detection of asymptomatic recurrences

Objetivos. Determinar la rentabilidad diagnóstica de la PET-TAC con 18F-FDG en la detección de recidivas asintomáticas en pacientes con linfoma. Definir patrones de captación indicativos de recidiva. Material y métodos. Se incluyeron de forma retrospectiva y longitudinal pacientes afectos de linfoma con los siguientes criterios de inclusión: remisión completa clínica con estudio PET-TAC negativo. Se realizó seguimiento convencional de estos pacientes únicamente mediante PET-TAC con 18F-FDG según técnica estándar. Se analizaron las localizaciones patológicas (supra e infradiafragmáticas) y su carácter (único o múltiple) con vistas a determinar patrones metabólicos fidedignos de recidiva. El diagnóstico final se estableció por análisis histopatológico o seguimiento clínico-radiológico superior a 8 meses. Resultados. Se incluyeron 199 exploraciones pertenecientes a 106 pacientes, 59 afectos de linfoma de Hodgkin y 47 de linfoma no Hodgkin. Veintisiete estudios fueron indicativos de recidiva desde el punto de vista metabólico. De ellos 14 fueron falsos positivos (FP), 10 pacientes y 13 verdaderos positivos, 8 pacientes. El resto de los estudios fueron verdaderos negativos y no se detectaron falsos negativos. El patrón más frecuentemente relacionado con recidiva fue la afectación adenopática infradiafragmática mientras que la mayoría de los FP poseían afectación supradiafragmática aislada. Los parámetros de sensibilidad, especificidad, VPP, VPN y exactitud diagnóstica por exploración fueron de: 100%, 92%, 48%, 100% y 93% respectivamente. Conclusión. La PET-TAC con 18F-FDG es una técnica sensible en la detección de recidivas asintomáticas de pacientes con linfoma durante el seguimiento. El carácter múltiple y las localizaciones infradiafragmáticas fueron los parámetros mejor correlacionados con el diagnóstico de recidiva(AU)

Aim. To assess the diagnostic accuracy of 18F-FDG-PET/CT in detecting asymptomatic recurrences in patients with lymphoma. To define uptake patterns of recurrence indicative of recurrence. Material and methods. Those patients with lymphoma who fulfilled the following inclusion criteria of clinical complete remission and negative PET/CT study were included retrospectively and longitudinally. Conventional surveillance of these patients was performed only by 18F-FDG PET/CT following a standardized procedure. Pathologic locations (supra- and infradiaphragmatic) and their character (single or multiple) were analyzed in order to determine reliable metabolic patterns of recurrence. The final diagnosis was established by histopathological analysis or clinical follow-up greater than 8 months. Results. A total of 199 explorations belonging to 106 patients with lymphoma were included. Of these patients, 59 had Hodgkin's lymphoma and 47 non-Hodgkin's lymphoma. There was suspicion of relapse from the metabolic point of view in 27 of the PET/CT scans. Of these, 14 (10 patients) were false positive (FP), and 13 (8 patients) true positive. The remaining studies were true negative, no false negatives being detected. The pattern most frequently related to recurrence was infradiaphragmatic lymph node involvement while most of the FP had isolated supradiaphragmatic involvement. Sensitivity, specificity, PPV, NPV and diagnostic accuracy of PET/CT parameters for the study were 100%, 92%, 48%, 100% and 93%, respectively. Conclusion. 18F-FDG-PET/CT is a sensitive technique in the detection of asymptomatic recurrences in patients with lymphoma during their follow-up. Multiple character and infradiaphragmatic locations were the patterns that best correlated to the diagnosis of recurrence(AU)

18F-FDG-PET/CT in the surveillance of patients with lymphoma: detection of asymptomatic recurrences.

AIM: To assess the diagnostic accuracy of (18)F-FDG-PET/CT in detecting asymptomatic recurrences in patients with lymphoma. To define uptake patterns of recurrence indicative of recurrence. MATERIAL AND METHODS: Those patients with lymphoma who fulfilled the following inclusion criteria of clinical complete remission and negative PET/CT study were included retrospectively and longitudinally. Conventional surveillance of these patients was performed only by (18)F-FDG PET/CT following a standardized procedure. Pathologic locations (supra- and infradiaphragmatic) and their character (single or multiple) were analyzed in order to determine reliable metabolic patterns of recurrence. The final diagnosis was established by histopathological analysis or clinical follow-up greater than 8 months. RESULTS: A total of 199 explorations belonging to 106 patients with lymphoma were included. Of these patients, 59 had Hodgkin's lymphoma and 47 non-Hodgkin's lymphoma. There was suspicion of relapse from the metabolic point of view in 27 of the PET/CT scans. Of these, 14 (10 patients) were false positive (FP), and 13 (8 patients) true positive. The remaining studies were true negative, no false negatives being detected. The pattern most frequently related to recurrence was infradiaphragmatic lymph node involvement while most of the FP had isolated supradiaphragmatic involvement. Sensitivity, specificity, PPV, NPV and diagnostic accuracy of PET/CT parameters for the study were 100%, 92%, 48%, 100% and 93%, respectively. CONCLUSION: (18)F-FDG-PET/CT is a sensitive technique in the detection of asymptomatic recurrences in patients with lymphoma during their follow-up. Multiple character and infradiaphragmatic locations were the patterns that best correlated to the diagnosis of recurrence.

[PET-CT with intravenous contrast in the evaluation of patients with lymphoma. Contribution to diagnostic indications]. / PET-TAC con contraste intravenoso en la valoración de pacientes con linfoma. Aproximación hacia las indicaciones diagnósticas.

AIM: To define the utility of intravenous contrast administration in the PET-CT (PET-CTc) in patients with lymphoma in order to determine its possible indications. MATERIAL AND METHODS: 78 patients with lymphoma were prospectively evaluated. All underwent simultaneous PET-CTc scans in a hybrid system for staging (8), evaluation of response to treatment (29), suspicion of recurrence (9) and complete remission control (48). The PET scan was acquired by a conventional method and the diagnostic CT scan was performed according to radiological protocol. Both examinations were evaluated blinded and independently, analyzing 28 anatomical locations in order to determine the degree of agreement. Final diagnosis was established by the clinician based on the histological study, results of other diagnostic techniques or clinical follow-up. RESULTS: The final result of both techniques were concordant in 87/94 studies (92.5%). A total of 158 (36 FP) pathological locations were detected with PET-CT and 189 (71 FP) with CTc, with 72 locations being discordant between both techniques. Global sensitivity, specificity, PPV and NPV were 93%, 98%, 77% and 99%; and 94%, 97%, 62% and 99%, respectively. CONCLUSIONS: Administration of intravenous contrast does not seem to provide any advantage in the determination of nodal and extranodal disease in lymphoma patients. The low prevalence of disease probably accounts for the limited PPV of both techniques. An increase of our sample size, with a greater homogeneity of the groups, should offer more reliable results.

PET-TAC con contraste intravenoso en la valoración de pacientes con linfoma. Aproximación hacia las indicaciones diagnósticas / PET-CT with intravenous contrast in the evaluation of patients with lymphoma. Contribution to diagnostic indications

ObjetivoDefinir la utilidad de la administración de contraste intravenoso en la PET-TAC (PET-TACc) en pacientes con linfoma, con el fin de determinar sus posibles indicaciones.Material y métodoSe ha valorado prospectivamente a 78 pacientes con linfoma, a los que se les realizó 94 estudios PET-TACc de manera simultánea en un equipo híbrido para estadiaje (8), valoración de respuesta al tratamiento (29), sospecha de recidiva (9) y control en remisión (48). El estudio PET se adquirió de forma convencional y la TACc se realizó según protocolo radiológico.Material y métodoSe valoraron ambas exploraciones, de forma independiente y ciega, analizando 28 localizaciones anatómicas con el fin de determinar la sensibilidad (S), la especificidad (E), el valor predictivo positivo (VPP) y el valor predictivo negativo (VPN), así como el grado de concordancia. El diagnóstico final fue establecido por el clínico atendiendo a la confirmación histológica, al resultado de otras técnicas diagnósticas o al seguimiento clínico.ResultadosAmbas técnicas fueron concordantes en su resultado final en 87/94 estudios (92,5%). Se encontraron 158 (36 falsos positivos [FP]) localizaciones patológicas con PET-TAC y 189 (71 FP) con TACc, siendo 72 discordantes entre ambas técnicas.ResultadosLa S, la E, el VPP y el VPN de la PET-TAC y de la TACc fueron del 93, el 98, el 77 y el 99%, y del 94, el 97, el 62 y el 99%, respectivamente.ConclusionesLa administración de contraste intravenoso no parece aportar ventajas en la determinación de patología ganglionar ni extraganglionar en los pacientes con linfoma. La baja prevalencia de enfermedad probablemente sea la causa del limitado VPP de ambas técnicas. La ampliación de nuestra casuística, con una mayor homogeneidad de los grupos, ofrecerá resultados más fiables(AU9

AimTo define the utility of intravenous contrast administration in the PET-CT (PET-CTc) in patients with lymphoma in order to determine its possible indications.Material and methods78 patients with lymphoma were prospectively evaluated. All underwent simultaneous PET-CTc scans in a hybrid system for staging (8), evaluation of response to treatment (29), suspicion of recurrence (9) and complete remission control (48). The PET scan was acquired by a conventional method and the diagnostic CT scan was performed according to radiological protocol.Material and methodsBoth examinations were evaluated blinded and independently, analyzing 28 anatomical locations in order to determine the degree of agreement. Final diagnosis was established by the clinician based on the histological study, results of other diagnostic techniques or clinical follow-up.ResultsThe final result of both techniques were concordant in 87/94 studies (92.5%). A total of 158 (36 FP) pathological locations were detected with PET-CT and 189 (71 FP) with CTc, with 72 locations being discordant between both techniques.ResultsGlobal sensitivity, specificity, PPV and NPV were 93%, 98%, 77% and 99%; and 94%, 97%, 62% and 99%, respectively.ConclusionsAdministration of intravenous contrast does not seem to provide any advantage in the determination of nodal and extranodal disease in lymphoma patients. The low prevalence of disease probably accounts for the limited PPV of both techniques. An increase of our sample size, with a greater homogeneity of the groups, should offer more reliable results(AU)