[(18)F-FDG PET-CT and respiratory synchronization: effect in the detection and catalogation of pulmonary lesions]. / (18)F-FDG PET-TAC y sincronización respiratoria: efecto en la detección y catalogación de lesiones pulmonares.

UNLABELLED: The respiratory movement reduces the sensitivity in the detection of pulmonary lesions. The synchronized acquisition of PET with respiratory movement (4D) can reduce this inconvenient. Our objective was assess the effect of 4D PET-CT in the metabolic activity of (18)F FDG and final classification of pulmonary lesions. MATERIAL AND METHODS: 12 patients with 18 pulmonary lesions with sizes within 0.8-4cm were assessed. The maximum SUV was obtained in the imaging acquired in standard conditions (3D) and the obtained in the respiratory period with higher metabolic activity in 4D images. The difference of percentage between both values was calculated. Moreover were evaluated the changes of the classification of pulmonary nodes (benign or malignant) obtained from the assessment of 4D and 3D PET images. RESULTS: 17/18 pulmonary lesions showed an increase in the SUV(max) value in the 4D with respect to 3D image. 5 lesions showed SUV(max) values >2.5 in 4D image and <2.5 in 3D image. From these 3 were correctly catalogued as malignant with 4D although the number of false positive increased to 2. CONCLUSION: (18)F-FDG 4D PET-CT shows values of metabolic activity more realistic allowing the correct classification reducing the false negative although increasing the false positive.

[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)

18F-FDG PET-TAC y sincronización respiratoria: efecto en la detección y catalogación de lesiones pulmonares / F-FDG PET-CT and respiratory sincronization: Effect in the detection and catalogation of pulmonary lesions

El movimiento respiratorio reduce la sensibilidad de la PET en la detección de lesiones pulmonares. La adquisición de la 18F-FDG PET-TAC sincronizada con el movimiento respiratorio (4D) puede salvar este inconveniente. Nuestro objetivo fue determinar el efecto de la PET 4D en la actividad metabólica de la 18F-FDG así como en la catalogación final de lesiones pulmonares.Material y métodosSe ha valorado a 12 pacientes que presentaban 18 lesiones pulmonares con tamaños de entre 0,8 y 4cm. Se determinó el SUVmáx en imagen adquirida en condiciones estándares (3D) y el obtenido en el período del ciclo respiratorio con mayor actividad metabólica en imagen 4D. Se calculó el porcentaje de diferencia entre ambos. Asimismo, se evaluaron los cambios en la catalogación de las lesiones pulmonares (benignos o malignos) obtenidos al valorar la imagen PET 4D con respecto a la 3D.ResultadosDiecisiete de las 18 lesiones pulmonares experimentaron un ascenso en su valor SUVmáx en la imagen 4D con respecto al estudio 3D. Cinco lesiones mostraron valores de SUVmáx superior a 2,5 en imagen 4D e inferior a 2,5 en imagen 3D. De éstas, 3 fueron correctamente catalogadas como malignas con la técnica 4D, aunque aumentó el número de falsos positivos a 2.ConclusiónLa adquisición de la 18F-FDG PET-TAC en 4D muestra valores de actividad metabólica más acordes con la realidad, permitiendo la clasificación correcta de lesiones malignas y reduciendo los falsos negativos aunque aumentando los falsos positivos(AU)

The respiratory movement reduces the sensitivity in the detection of pulmonary lesions. The synchroniced acquisition of PET with respiratory movement (4D) can reduce this inconvenient. Our objective was assess the effect of 4D PET-CT in the metabolic activity of 18F FDG and final classification of pulmonary lesions.Material and methods12 patients with 18 pulmonary lesions with sizes within 0.8–4cm were assessed. The maximum SUV was obtained in the imaging acquired in standard conditions (3D) and the obtained in the respiratory period with higher metabolic activity in 4D images. The difference of percentage between both values was calculated. Moreover were evaluated the changes of the classification of pulmonary nodes (benign or malignant) obtained from the assessment of 4D and 3D PET images.Results17/18 pulmonary lesions showed an increase in the SUVmax value in the 4D with respect to 3D image. 5 lesions showed SUVmax values >2.5 in 4D image and <2.5 in 3D image. From these 3 were correctly catalogued as malignant with 4D although the number of false positive increased to 2.Conclusion18F-FDG 4D PET-CT shows values of metabolic activity more realistic allowing the correct classification reducing the false negative although increasing the false positive(AU)

Enfermedad de Paget: presentación "clásica" / Paget's disease. Classical presentation

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Islote óseo gigante vertebral / Vertebral giant bone island

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