Contribution of V/Q SPECT to planar scintigraphy in the diagnosis of pulmonary embolism / Contribución de la SPECT V/Q a la gammagrafía planar en el diagnóstico del tromboembolismo pulmonar

Aim: To evaluate the feasibility of V/Q SPECT and analyze its contribution to planar V/Q lung scintigraphy in the diagnosis of pulmonary embolism (PE). Material and methods: A total of 109 patients with suspected PE showing Wells score > 2 and elevated D-dimer were studied. The V/Q could not be completed in 7 patients, so they were excluded. Ventilation and perfusion scans were done using Technegas and 99mTc-MAA. Planar study included 8 projections on a 256 × 256 matrix and 128 projections on a 128 × 128 matrix were acquired for the SPECT study, applying an iterative method. Planar images were interpreted according to modified PIOPED criteria, and SPECT by the guidelines of the EANMMI. The results with both techniques were compared. Results: V/Q planar scintigraphy and SPECT could be performed in 102 patients. V/Q planar scintigraphy was considered "diagnostic" in 39 of the 102 patients, and "non-diagnostic" in 63. Of the 39 "diagnostic" studies, 31 were reported as high probability of PE and 8 as normal. Of the 63 "non-diagnostic", 26 corresponded to intermediate, 29 to low, and 8 to very low probability. The SPECT study was "diagnostic" in 97 and indeterminate in only 5. All patients with a high probability planar scintigraphy had a positive SPECT. In the 8 patients with a normal planar scintigraphy SPECT was negative in 5 and positive in 3. In the 63 patients with a "non-diagnostic" planar scintigraphy SPECT was "diagnostic" in 58 of them, positive in 17 and negative in 41. Conclusion: V/Q SPECT is a feasible technique as it was performed in 102 of the 109 patients who were enrolled in the study (94%). The addition of V/Q SPECT to planar V/Q decreases the number of "non-diagnostic" reports from 62% in planar scintigraphy to 4.9% in SPECT. Therefore, V/Q SPECT should be included in the diagnosis approach of PE due to its high diagnostic yield (AU)

Objetivo: Evaluar la factibilidad de la SPECT V/Q y analizar su contribución a la gammagrafía planar en el diagnóstico del tromboembolismo pulmonar (TEP). Material y métodos: Estudio en 109 pacientes con sospecha de TEP, con escala de Wells > 2 y dímero D elevado. Se excluyeron 7 pacientes porque no pudieron completar el estudio. Para la gammagrafía de ventilación se empleó Technegas y para el estudio de perfusión 99mTc-MAA. El estudio planar incluyó 8 proyecciones en matriz 256 × 256, en la SPECT se adquirieron 128 proyecciones en matriz 128 × 128, aplicándose una reconstrucción iterativa. Las imágenes planares fueron interpretadas según criterios PIOPED modificados y la SPECT según la guía de la EANMMI. Se compararon los resultados obtenidos entre ambas técnicas. Resultados: Fue posible realizar el estudio V/Q planar y la SPECT en 102. La gammagrafía planar V/Q fue considerada «diagnóstica» en 39 de los 102 pacientes, y «no diagnóstica» en 63. De las 39 gammagrafías «diagnósticas», 31 fueron de alta probabilidad para TEP y 8 fueron normales. De las 63 gammagrafías «no diagnósticas», 26 fueron probabilidad intermedia, 29 baja y 8 muy baja probabilidad. La SPECT fue diagnóstica en 97 e indeterminada solo en 5. En todos los pacientes con alta probabilidad en la gammagrafía planar la SPECT fue positiva. En los 8 pacientes con gammagrafía planar normal la SPECT fue negativa en 5 y positiva en 3. En 63 pacientes con gammagrafía planar «no diagnóstica», la SPECT fue «diagnóstica» en 58 de ellos, siendo positiva en 17 y negativa en 41. Conclusión: La SPECT V/Q es una técnica factible, ya que se realizó en 102 de los 109 pacientes incluidos en el estudio (94%). La incorporación de la SPECT V/Q a la gammagrafía planar disminuyó el número de informes «no diagnóstico» de un 62% en la gammagrafía planar a un 4,9% con la SPECT. Por lo tanto la SPECT V/Q debe incluirse en el diagnóstico de TEP por su alto rendimiento diagnóstico (AU)

Comparison of 99mTc-sestamibi and 11C-methionine PET/CT in the localization of parathyroid adenomas in primary hyperparathyroidism / Comparación del 99mTc-sestamibi y 11C-metionina PET/TC en la localización del adenoma de paratiroides en el hiperparatiroidismo primario

Aim: To evaluate the usefulness of 11C-methionine PET/CT (MET) in the localization of the parathyroid adenomas and to compare the results with those obtained with the conventional technique in double-phase 99mTc-sestamibi scintigraphy (MIBI). We evaluated the optimal timing to acquire MET images. Material and methods: A prospective study that included 14 patients (mean age: 65.5 ± 9.7 years) with primary hyperparathyroidism (PH) who underwent surgery was performed. Mean serum iPTH was 215.8 ± 108 pg/mL and serum calcium 10.8 ± 0.9 mg/dL. MIBI (planar and SPECT) was obtained 10 min and 2–3 h after injection of 740 MBq (20 mCi) of 99mTc-sestamibi. MET was obtained 10 min and 40 min after injection of 740 MBq (20 mCi) of 11C-methionine. MIBI and MET images were visually evaluated and compared. A score for 10 min and 40 min MET images from 0 (no abnormal uptake) to 3 (intense uptake) was assigned. Results: MIBI and MET were positive and concordant in 11/14 patients and in 10 of them the parathyroid adenoma was correctly localized. In 3/14 MIBI was positive and MET negative (MIBI correctly localized the parathyroid adenoma in 2 of them). According to the timing of MET imaging acquisition, the 10 min and 40 min acquisition showed the same score in 10 patients, it was higher at 10 min acquisition in 3 and in 1 the parathyroid adenoma was only detected at 40 min acquisition. Conclusion: MIBI remains the technique of choice for the localization of parathyroid adenomas in patients with PH. MET may play a complementary role in selected patients. Delayed acquisition should be included in the MET protocol when the early acquisition is negative (AU)

Objetivos: Evaluar la utilidad de la 11C-metionina PET/TC (MET) en la localización de adenoma de paratiroides comparado con la técnica convencional en doble fase con 99mTc-sestamibi (MIBI). Evaluar el tiempo adecuado para la adquisición de imágenes MET. Material y métodos: Este estudio prospectivo incluyó 14 pacientes (edad: 65,5 ± 9,7 años) con hiperparatiroidismo primario (HPTP) sometidos a cirugía. La iPTH fue de 215,8 ± 108 pg/mL y el calcio sérico 10,8 ± 0,9 mg/dL. El MIBI (planar, SPECT) fue realizado a los 10 min y 2-3 horas tras la inyección de 740 MBq (20 mCi) de MIBI. La MET fue realizada 10 min y 40 min tras la inyección de 740 MBq (20 mCi) de MET. Las imágenes fueron evaluadas visualmente y comparadas. Las imágenes con MET a 10 min y 40 min fueron valoradas según el grado de captación (0[no captación] a 3[intensa]). Resultados: MIBI y MET fueron positivos y concordantes en 11/14 pacientes, en 10 de ellos el adenoma de paratiroides fue correctamente localizado. En 3/14 el MIBI fue positivo y la MET negativa (el MIBI localizó correctamente 2). Con respecto al tiempo de adquisición imágenes MET a los 10 min y 40 min se observó la misma puntuación en 10 pacientes, fue mayor a los 10 min en 3 y en un paciente sólo fue positivo a los 40 min. Conclusiones: El MIBI continúa siendo la técnica de elección para la localización del adenoma de paratiroides en pacientes con HPTP. La MET podría tener un papel complementario en pacientes seleccionados. La adquisición tardía de la MET debería ser incluida cuando la imagen precoz sea negativa (AU)

Contribution of V/Q SPECT to planar scintigraphy in the diagnosis of pulmonary embolism.

AIM: To evaluate the feasibility of V/Q SPECT and analyze its contribution to planar V/Q lung scintigraphy in the diagnosis of pulmonary embolism (PE). MATERIAL AND METHODS: A total of 109 patients with suspected PE showing Wells score>2 and elevated D-dimer were studied. The V/Q could not be completed in 7 patients, so they were excluded. Ventilation and perfusion scans were done using Technegas and (99m)Tc-MAA. Planar study included 8 projections on a 256×256 matrix and 128 projections on a 128×128 matrix were acquired for the SPECT study, applying an iterative method. Planar images were interpreted according to modified PIOPED criteria, and SPECT by the guidelines of the EANMMI. The results with both techniques were compared. RESULTS: V/Q planar scintigraphy and SPECT could be performed in 102 patients. V/Q planar scintigraphy was considered "diagnostic" in 39 of the 102 patients, and "non-diagnostic" in 63. Of the 39 "diagnostic" studies, 31 were reported as high probability of PE and 8 as normal. Of the 63 "non-diagnostic", 26 corresponded to intermediate, 29 to low, and 8 to very low probability. The SPECT study was "diagnostic" in 97 and indeterminate in only 5. All patients with a high probability planar scintigraphy had a positive SPECT. In the 8 patients with a normal planar scintigraphy SPECT was negative in 5 and positive in 3. In the 63 patients with a "non-diagnostic" planar scintigraphy SPECT was "diagnostic" in 58 of them, positive in 17 and negative in 41. CONCLUSION: V/Q SPECT is a feasible technique as it was performed in 102 of the 109 patients who were enrolled in the study (94%). The addition of V/Q SPECT to planar V/Q decreases the number of "non-diagnostic" reports from 62% in planar scintigraphy to 4.9% in SPECT. Therefore, V/Q SPECT should be included in the diagnosis approach of PE due to its high diagnostic yield.

Comparison of 99mTc-sestamibi and 11C-methionine PET/CT in the localization of parathyroid adenomas in primary hyperparathyroidism.

AIM: To evaluate the usefulness of (11)C-methionine PET/CT (MET) in the localization of the parathyroid adenomas and to compare the results with those obtained with the conventional technique in double-phase (99m)Tc-sestamibi scintigraphy (MIBI). We evaluated the optimal timing to acquire MET images. MATERIAL AND METHODS: A prospective study that included 14 patients (mean age: 65.5 ± 9.7 years) with primary hyperparathyroidism (PH) who underwent surgery was performed. Mean serum iPTH was 215.8 ± 108 pg/mL and serum calcium 10.8 ± 0.9 mg/dL. MIBI (planar and SPECT) was obtained 10 min and 2-3h after injection of 740 MBq (20 mCi) of (99m)Tc-sestamibi. MET was obtained 10 min and 40 min after injection of 740 MBq (20 mCi) of (11)C-methionine. MIBI and MET images were visually evaluated and compared. A score for 10 min and 40 min MET images from 0 (no abnormal uptake) to 3 (intense uptake) was assigned. RESULTS: MIBI and MET were positive and concordant in 11/14 patients and in 10 of them the parathyroid adenoma was correctly localized. In 3/14 MIBI was positive and MET negative (MIBI correctly localized the parathyroid adenoma in 2 of them). According to the timing of MET imaging acquisition, the 10 min and 40 min acquisition showed the same score in 10 patients, it was higher at 10 min acquisition in 3 and in 1 the parathyroid adenoma was only detected at 40 min acquisition. CONCLUSION: MIBI remains the technique of choice for the localization of parathyroid adenomas in patients with PH. MET may play a complementary role in selected patients. Delayed acquisition should be included in the MET protocol when the early acquisition is negative.

Comparison of early (60 min) and delayed (180 min) acquisition of 18F-FDG PET/CT in large vessel vasculitis

Objetivo. Comparar la contribución de la adquisición con 18F-FDG-PET/TC a 180 min con la de 60 min en sospecha de vasculitis de grandes vasos (VGV). Material y métodos. Este estudio prospectivo incluyó 23 pacientes. El estudio PET/TC fue adquirido a 60 y 180 min (precoz y tardío) tras la administración de 18F-FDG. Se realizó un análisis visual de las imágenes valorando los troncos supraaórticos (TSA), la aorta torácica (AT), la abdominal (AA), las arterias ilíacas (AI) y las femoro/tibioperoneas (AFT). En las 115 regiones vasculares se evaluó la intensidad (0-3) y el patrón de captación (difuso/lineal). Resultados. En 20/115 regiones vasculares (17,4%) no hubo captación en la adquisición precoz y tardía. De las 95 regiones (82,6%) con captación en la adquisición precoz la intensidad no cambió en la tardía en 46 y cambió en 49. De esas 49 regiones en las que la intensidad cambió, esta disminuyó en 36 y aumentó en 13 (AT: 8, TSA: 5). En ningún caso la intensidad aumentó en la AA, las AI y las AFT. El patrón de captación en la AT fue difuso en la adquisición precoz en 16 pacientes, en 7 de ellos cambió a lineal en la tardía y desapareció en 9. El patrón precoz fue lineal en 7 pacientes, 6 de ellos mostraron un aumento de intensidad en la tardía y en uno permaneció igual. Conclusión. La adquisición tardía de 180 min con FDG-PET/TC proporciona una más detallada visualización de la pared vascular, mostrando la desaparición de la actividad del pool vascular y contribuyendo a un más correcto diagnóstico de VGV(AU)

Purpose. To compare the contribution of the 18F-FDG-PET/CT acquisition at 180 min and at 60 min in suspicion of large vessel vasculitis (LVV). Material and methods. A prospective study including 23 patients was performed. PET/CT was acquired at 60 and 180 min (early and delayed scan) after 18F-FDG injection. A visual analysis was performed at the supra-aortic trunks (SAT), thoracic aorta (TA), abdominal aorta (AA), iliac arteries (IA) and femoral/tibioperoneal arteries (FTA). Intensity (0–3) and uptake pattern (diffuse/linear) were assessed in the 115 vascular regions. Results. There was no FDG uptake in the early and delayed acquisition in 20/115 vascular regions (17.4%). Of the 95 regions (82.6%) showing FDG uptake at the early, delayed or both acquisitions, intensity did not change in the delayed acquisition in 46 and changed in 49. Of the 49 regions in which the intensity changed, it decreased in 36 and increased in 13 (TA:8, SAT:5). AA, IA and FTA intensity did not increase in any of the cases. Uptake pattern at the TA in the early acquisition was diffuse in 16 patients. In 7, it changed to linear and in 9 the uptake disappeared. The early pattern was linear in 7 patients and 6 of them showed increased intensity in the delayed acquisition and in 1 remained the same. Conclusion. The 180 min delayed FDG-PET/CT acquisition provides a more detailed visualized of the vessel wall, showing the washout of the blood pool activity. Therefore, it may contribute to a more accurate diagnosis of LVVAU)(AU)

Comparison of early (60 min) and delayed (180 min) acquisition of 18F-FDG PET/CT in large vessel vasculitis.

PURPOSE: To compare the contribution of the (18)F-FDG-PET/CT acquisition at 180 min and at 60 min in suspicion of large vessel vasculitis (LVV). MATERIAL AND METHODS: A prospective study including 23 patients was performed. PET/CT was acquired at 60 and 180 min (early and delayed scan) after (18)F-FDG injection. A visual analysis was performed at the supra-aortic trunks (SAT), thoracic aorta (TA), abdominal aorta (AA), iliac arteries (IA) and femoral/tibioperoneal arteries (FTA). Intensity (0-3) and uptake pattern (diffuse/linear) were assessed in the 115 vascular regions. RESULTS: There was no FDG uptake in the early and delayed acquisition in 20/115 vascular regions (17.4%). Of the 95 regions (82.6%) showing FDG uptake at the early, delayed or both acquisitions, intensity did not change in the delayed acquisition in 46 and changed in 49. Of the 49 regions in which the intensity changed, it decreased in 36 and increased in 13 (TA:8, SAT:5). AA, IA and FTA intensity did not increase in any of the cases. Uptake pattern at the TA in the early acquisition was diffuse in 16 patients. In 7, it changed to linear and in 9 the uptake disappeared. The early pattern was linear in 7 patients and 6 of them showed increased intensity in the delayed acquisition and in 1 remained the same. CONCLUSION: The 180 min delayed FDG-PET/CT acquisition provides a more detailed visualized of the vessel wall, showing the washout of the blood pool activity. Therefore, it may contribute to a more accurate diagnosis of LVV.

Contribution of 18F-sodium fluoride PET/CT to the study of the carotid atheroma calcification / Caracterizacion de la calcificacion del ateroma carotideo mediante 18F-fluoruro PET/TAC

Aim. To assess the calcification process of the carotid plaque by 18F-sodium fluoride PET/CT imaging. Material and methods. A prospectively designed study including 15 patients in whom an atheroma plaque was detected by contrast enhanced CT scan during a neurological work-up was performed. A total of 29 plaques, 19 asymptomatic and 10 symptomatic, were studied. An 18F-sodium fluoride PET/CT scan was acquired 180min after the i.v. injection of 370 MBq of 18F-sodium fluoride in all the patients. The images obtained were analyzed visually according to the intensity of the uptake. Results. All the plaques showed 18F-sodium fluoride uptake, regardless of the intensity. However, the plaques of the symptomatic group showed a level of 2 or greater intensity while the intensity in 6 of the 19 in the asymptomatic group was lower than 2. Conclusions. Although the study is limited by the small number of cases, the results show the feasibility of the technique to study the calcification of the atheroma using 18F-sodium fluoride and suggest an association between symptomatology and higher uptake of 18F-sodium fluoride. Thus, these results encourage us to continue this study, with the inclusion of a larger number of patients (AU)

Objetivo. Estudiar el proceso de calcificación de la placa de ateroma carotideo mediante 18F-fluoruro sódico PET/TAC. Material y métodos. Estudio prospectivo en 15 pacientes con ateromatosis carotidea detectada por angio-TAC durante su estudio neurológico. El total de placas de ateroma estudiadas fue de 29, 19 asintomáticas y 10 sintomáticas. En todos los pacientes se adquirió un estudio PET/TAC a los 180min De la administración intravenosa de 370 MBq de 18F-fluoruro sódico. Las imágenes se analizaron visualmente considerando la intensidad de captación. Resultados. Todas las placas captaron 18F-fluoruro sódico, con independencia de la intensidad. Sin embargo las placas del grupo sintomático mostraron una intensidad de 2 o mayor mientras que 6 de las 19 del grupo asintomático mostraron una intensidad inferior a 2. Conclusiones. Aunque el estudio está limitado por el pequeño número de casos, los resultados muestran la aplicabilidad de la técnica al estudio de la calcificación del ateroma con 18F-fluoruro sódico y sugieren una asociación entre la sintomatología y una mayor captación de 18F-fluoruro sódico. Por ello, estos resultados nos animan a continuar este estudio incluyendo un mayor número de pacientes (AU)

Contribution of 18F-sodium fluoride PET/CT to the study of the carotid atheroma calcification.

AIM: To assess the calcification process of the carotid plaque by (18)F-sodium fluoride PET/CT imaging. MATERIAL AND METHODS: A prospectively designed study including 15 patients in whom an atheroma plaque was detected by contrast enhanced CT scan during a neurological work-up was performed. A total of 29 plaques, 19 asymptomatic and 10 symptomatic, were studied. An (18)F-sodium fluoride PET/CT scan was acquired 180min after the i.v. injection of 370 MBq of (18)F-sodium fluoride in all the patients. The images obtained were analyzed visually according to the intensity of the uptake. RESULTS: All the plaques showed (18)F-sodium fluoride uptake, regardless of the intensity. However, the plaques of the symptomatic group showed a level of 2 or greater intensity while the intensity in 6 of the 19 in the asymptomatic group was lower than 2. CONCLUSIONS: Although the study is limited by the small number of cases, the results show the feasibility of the technique to study the calcification of the atheroma using (18)F-sodium fluoride and suggest an association between symptomatology and higher uptake of (18)F-sodium fluoride. Thus, these results encourage us to continue this study, with the inclusion of a larger number of patients.