Ventilation/Perfusion SPECT lung scintigraphy and computed tomography pulmonary angiography in patients with clinical suspicion of pulmonary embolism / Gammagrafía pulmonar SPECT de Ventilación/Perfusión y angiografía pulmonar computerizada en pacientes con sospecha clínica de tromboembolismo pulmonar

The aim was to compare ventilation/perfusion SPECT lung scintigraphy (V/Q-SPECT) and computed tomography pulmonary angiography (CTPA) in patients with suspicion of pulmonary embolism (PE). Material and methods. This prospectively designed study included 53 patients with intermediate or high clinical probability of PE. A V/Q-SPECT and CTPA was performed on all patients. The V/Q-SPECT was interpreted according to the European Association of Nuclear Medicine and Molecular Imaging (EANMMI) guidelines. CTPA was reported as positive, negative, or indeterminate. Results. CTPA was positive in 22 cases, negative in 28, and indeterminate in 3. V/Q-SPECT was positive in 27 cases, negative in 24, and non-diagnostic in 2. In the 22 with positive CTPA, V/Q-SPECT was positive in 18, negative in 3, and non-diagnostic in 1. In the 28 with negative CTPA, V/Q-SPECT was positive in 8, negative in 19, and non-diagnostic in 1. In the 3 with indeterminate CTPA, V/Q-SPECT was positive in 1 and negative in 2. In the 2 non-diagnostic cases V/Q-SPECT, CTPA was positive in 1 and negative in one. In the 10 high clinical probabilities, CTPA and V/Q-SPECT were positive in 7, negative in 2, and in 1, CTPA was positive and V/Q-SPECT negative. In the 38 intermediate probability group, CTPA and V/Q-SPECT were positive in 11, negative in 17, with CTPA negative and V/Q-SPECT positive in 8, and in 2 CTPA was positive and V/Q-SPECT negative. The results show that V/Q-SPECT detected PE in 5 patients more than CTPA. Conclusion. Our results show a 77% concordance of both techniques. Overall V/Q-SPECT detected PE in 18% more patients than CTPA in the intermediate group. Both techniques have a complementary role when a diagnosis cannot be made with one of them (AU)

Objetivo. Comparar la gammagrafía pulmonar SPECT de ventilación/perfusión (SPECT-V/Q) y la angiografía pulmonar computarizada (CTPA) en pacientes con sospecha de tromboembolismo pulmonar (TEP). Material y métodos. Estudio prospectivo en 53 pacientes con probabilidad intermedia y alta de TEP. A todos se les realizó SPECT-V/Q y CTPA. La SPECT-V/Q fue interpretada según la guía publicada por la European Association of Nuclear Medicine and Molecular Imaging (EANMMI). La CTPA fue reportada como positiva, negativa o indeterminada. Resultados. La CTPA fue positiva en 22, negativa en 28 e indeterminada en 3. La SPECT-V/Q fue positiva en 27, negativa en 24 y no diagnóstica en 2. En 22 con CTPA positiva, la SPECT-V/Q fue positiva en 18, negativa en 3 y no diagnóstica en una. En 28 con CTPA negativa, la SPECT-V/Q fue positiva en 8, negativa en 19 y no diagnóstica en uno. En 3 con CTPA indeterminada, la SPECT-V/Q fue positiva en una y negativa en 2. En 2 con SPECT-V/Q no diagnóstica, la CTPA fue positiva en una y negativa en una. En 10 con probabilidad clínica alta la CTPA y la SPECT-V/Q fueron positivas en 7, negativas en 2 y en una la CTPA fue positiva y la SPECT-V/Q negativa. En 38 con probabilidad intermedia la CTPA y la SPECT-V/Q fueron positivas en 11 y negativas en 17. En 8 la CTPA fue negativa y la SPECT-V/Q positiva, en 2 la CTPA fue positiva y la SPECT-V/Q negativa; por lo tanto, la SPECT-V/Q detectó TEP en 5 pacientes más de la CTPA. Conclusión. Nuestros resultados muestran un 77% de concordancia entre ambas técnicas. En general la SPECT-V/Q detectó TEP en 18% más pacientes que la CTPA en el grupo con probabilidad intermedia. Ambas técnicas tienen un papel complementario cuando el diagnóstico no puede ser alcanzado por una de ellas (AU)

Ventilation/Perfusion SPECT lung scintigraphy and computed tomography pulmonary angiography in patients with clinical suspicion of pulmonary embolism.

UNLABELLED: The aim was to compare ventilation/perfusion SPECT lung scintigraphy (V/Q-SPECT) and computed tomography pulmonary angiography (CTPA) in patients with suspicion of pulmonary embolism (PE). MATERIAL AND METHODS: This prospectively designed study included 53 patients with intermediate or high clinical probability of PE. A V/Q-SPECT and CTPA was performed on all patients. The V/Q-SPECT was interpreted according to the European Association of Nuclear Medicine and Molecular Imaging (EANMMI) guidelines. CTPA was reported as positive, negative, or indeterminate. RESULTS: CTPA was positive in 22 cases, negative in 28, and indeterminate in 3. V/Q-SPECT was positive in 27 cases, negative in 24, and non-diagnostic in 2. In the 22 with positive CTPA, V/Q-SPECT was positive in 18, negative in 3, and non-diagnostic in 1. In the 28 with negative CTPA, V/Q-SPECT was positive in 8, negative in 19, and non-diagnostic in 1. In the 3 with indeterminate CTPA, V/Q-SPECT was positive in 1 and negative in 2. In the 2 non-diagnostic cases V/Q-SPECT, CTPA was positive in 1 and negative in one. In the 10 high clinical probabilities, CTPA and V/Q-SPECT were positive in 7, negative in 2, and in 1, CTPA was positive and V/Q-SPECT negative. In the 38 intermediate probability group, CTPA and V/Q-SPECT were positive in 11, negative in 17, with CTPA negative and V/Q-SPECT positive in 8, and in 2 CTPA was positive and V/Q-SPECT negative. The results show that V/Q-SPECT detected PE in 5 patients more than CTPA. CONCLUSION: Our results show a 77% concordance of both techniques. Overall V/Q-SPECT detected PE in 18% more patients than CTPA in the intermediate group. Both techniques have a complementary role when a diagnosis cannot be made with one of them.

New insight of functional molecular imaging into the atheroma biology: 18F-NaF and 18F-FDG in symptomatic and asymptomatic carotid plaques after recent CVA. Preliminary results.

AIM: The identification of the vulnerable atheroma plaque could allow a more effective treatment of cerebrovascular accident (CVA). Active calcification and inflammation of the carotid atheroma were assessed and compared in symptomatic and asymptomatic plaques by 18F-NaF and 18F-FDG PET/CT. METHODS: Nine patients investigated for recent CVA and no preventive treatment with statins were enrolled. In each patient, at least one atheroma plaque was detected by CT angiogram. In total, 18 plaques were available: 9 symptomatic and 9 asymptomatic. 18F-NaF uptake and 18F-FDG uptake by each plaque were assessed visually and semiquantitatively by calculating target/background ratios (TBRs) and TBR indexes (TBR symptomatic/TBR asymptomatic and 18F-NaF TBR/18F-FDG TBR within each of the 2 clinical groups of plaques). RESULTS: All plaques showed 18F-NaF and 18F-FDG uptake, and semiquantitation showed higher 18F-NaF uptake by 11 of the 18 plaques, 6 symptomatic and 5 asymptomatic. In the symptomatic group, the mean 18F-NaF TBR was 2·12 ± 0·44, and in the asymptomatic group, it was 1·85 ± 0·46. The 18F-NaF/18F-FDG showed that, overall, 18F-NaF uptake is higher than 18F-FDG. In the symptomatic plaques, the 18F-NaF was higher for the low calcium content and the lowest for the high. CONCLUSION: Active calcification and inflammation are simultaneous processes in the symptomatic and asymptomatic carotid atheroma. However, active calcification seems predominant over inflammation in both groups. In the symptomatic plaques, the highest 18F-NaF uptake does not correspond with the largest calcium content. These patterns open new insights on the role of 18F-NaF in the study of calcification and in the identification of the vulnerable carotid atheroma.

18F-sodium fluoride PET/CT for the in vivo visualization of Mönckeberg's sclerosis in a diabetic patient / PET/TC con 18F-fluoruro sódico en la visualización in vivo de la esclerosis de Mönckeberg en un paciente diabético

Diabetes is a major frequent cause of atherosclerosis vascular disease. Arterial calcification in diabetic patients is responsible for peripheral vascular involvement. Molecular imaging using 18F-sodium fluoride (18F-NaF) positron emission tomography (PET)/computed tomography (CT) has been recently proposed as a marker to study the in vivo mineralization process in the atheroma plaque. A 69-year-old man with a history of type 2 diabetes and no clinical evidence of peripheral arterial disease underwent an 18F-NaF PET/CT scan. A linear, well-defined 18F-NaF uptake was detected along the femoral arteries. In addition, the CT component of the PET/CT identified an unsuspected “tram-track” calcification in his femoral arteries, suggestive of medial calcification (Mönckeberg's sclerosis). In other vascular territories, focal 18F-NaF uptake was also detected in carotid and aorta atheroma plaques. Molecular imaging with 18F-NaF PET/CT might provide new functional information about the in vivo vascular calcification process in diabetic patients (AU)

La diabetes es una causa frecuente de enfermedad vascular aterosclerótica. La calcificación vascular en pacientes diabéticos es responsable de la afectación vascular periférica. Recientemente se ha propuesto la imagen molecular usando tomografía por emisión de positrones (PET)/tomografía computerizada (TC) con 18F-fluoruro sódico (18F-NaF) como marcador para estudiar “in vivo” el proceso de mineralización en la placa de ateroma. Presentamos los hallazgos de la PET/TC 18F-NaF en un varón de 69 años con historia de diabetes tipo 2 y sin evidencia clínica de enfermedad arterial periférica. La PET/TC 18F-NaF demostró una captación lineal, bien definida, a lo largo de las arterias femorales. Además la componente TC de la PET/TC identificó un patrón de calcificación “en vías de tranvía” (“tram-track” pattern) en las arterias femorales sugestivo de calcificación de la capa media arterial (esclerosis de Mönckeberg). En otros territorios vasculares se detectó captación focal de 18F-NaF en placas de ateroma carotídeas y aórticas. La imagen molecular con PET/TC 18F-NaF podría proporcionar nueva información funcional sobre el proceso de calcificación vascular “in vivo” en pacientes diabéticos (AU)

(18)F-sodium fluoride PET/CT for the in vivo visualization of Mönckeberg's sclerosis in a diabetic patient.

Diabetes is a major frequent cause of atherosclerosis vascular disease. Arterial calcification in diabetic patients is responsible for peripheral vascular involvement. Molecular imaging using (18)F-sodium fluoride ((18)F-NaF) positron emission tomography (PET)/computed tomography (CT) has been recently proposed as a marker to study the in vivo mineralization process in the atheroma plaque. A 69-year-old man with a history of type 2 diabetes and no clinical evidence of peripheral arterial disease underwent an (18)F-NaF PET/CT scan. A linear, well-defined (18)F-NaF uptake was detected along the femoral arteries. In addition, the CT component of the PET/CT identified an unsuspected "tram-track" calcification in his femoral arteries, suggestive of medial calcification (Mönckeberg's sclerosis). In other vascular territories, focal (18)F-NaF uptake was also detected in carotid and aorta atheroma plaques. Molecular imaging with (18)F-NaF PET/CT might provide new functional information about the in vivo vascular calcification process in diabetic patients.

Assessment of aortitis by semiquantitative analysis of 180-min 18F-FDG PET/CT acquisition images.

PURPOSE: The aim of this study was to evaluate the contribution of semiquantitative analysis of 180-min (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT images for the assessment of aortitis in cases of suspected large vessel vasculitis (LVV) and to establish a threshold index for application in the clinical setting. METHODS: This prospective study included 43 patients (mean age 67.5 ± 12.9 years) with suspicion of LVV (25 with a final diagnosis of aortitis). (18)F-FDG PET/CT scan was acquired 180 min after injection of 7 MBq/kg of (18)F-FDG. A semiquantitative analysis was performed calculating the aortic wall maximum standardized uptake value (SUVmax) (T), the lumen SUVmax (B) and the target to background ratio (TBR). These results were also compared with those obtained in a control population. RESULTS: The mean aortic wall SUVmax was 2.00 ± 0.62 for patients with aortitis and 1.45 ± 0.31 for patients without aortitis (p < 0.0001). The TBR was 1.66 ± 0.26 for patients with aortitis and 1.24 ± 0.08 for patients without aortitis (p < 0.0001). The differences were also statistically significant when the patients with aortitis and controls were compared. Receiver-operating characteristic (ROC) analysis revealed that the area under the curve was greater for the TBR than for the aortic wall SUVmax (0.997 vs 0.871). The highest sensitivity and specificity was obtained for a TBR of 1.34 (sensitivity 100%, specificity 94.4%). CONCLUSION: Semiquantitative analysis of PET/CT images acquired 180 min after (18)F-FDG injection and the TBR index of 1.34 show very high accuracy and, therefore, are strongly recommended for the diagnosis of aortitis in the clinical setting.

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.