Utilidad de la tomografía de emisión de fotón único-tomografía computarizada en la biopsia selectiva del ganglio centinela en pacientes con melanoma / Utility of single photon emission computed tomography-computed tomography in selective sentinel lymph node biopsy in patients with melanoma

Objetivo: Evaluar la aportación de la linfogammagrafía con SPECT-TAC en la biopsia selectiva del ganglio centinela (BSGC) en pacientes con melanoma. Material y métodos: Estudio prospectivo (julio de 2009 a octubre de 2010) incluyendo 63 pacientes diagnosticados de melanoma (32 hombres y 31 mujeres), con edad media de 55 años y criterios de inclusión de BSGC. La localización de los melanomas fue: 28 en el tronco, 5 en la cabeza y el cuello, 16 en los miembros superiores y 17 en los miembros inferiores. Tres pacientes presentaban 2 melanomas. Se realizó linfogammagrafía preoperatoria tras la inyección pericicatricial/perilesional de 74 MBq de nanocoloide de albúmina humana marcada con99mTc, obteniéndose imágenes planares precoces, estudio tardío de cuerpo completo, imágenes sectoriales y SPECT-TAC de la zona de interés. Se compararon los hallazgos de la gammagrafía planar y la SPECT-TAC. Resultados: El ganglio centinela (GC) fue localizado mediante las imágenes planares en 62/63 (98%) pacientes. La SPECT-TAC localizó el GC en los 63 pacientes (100%). El número de GC detectados con SPECT-TAC fue superior al estudio planar en 27 pacientes. El estudio SPECT-TAC aportó información adicional (cambio de localización y/o precisión de la misma en GC de ubicación incierta) en 14/63 (22,2%) pacientes, implicando cambios en el abordaje quirúrgico y en la estadificación ganglionar. Conclusión: La SPECT-TAC detecta mayor número de GC que la gammagrafía planar, siendo más relevante su aportación en los melanomas de tronco y cabeza y en los de cuello. En un 22% modificó la localización del GC respecto a los hallazgos de la gammagrafía planar, facilitando un correcto abordaje quirúrgico (AU)

Objective: To assess the contribution of SPECT-CT lymphoscintigraphy in selective sentinel lymph node biopsy (SLNB) in patients with newly diagnosed malignant melanoma. Material and methods: A prospective study was made between July 2009 and October 2010. It included 63 patients diagnosed with melanoma (32 men and 31 women) with mean age of 55 years (range: 25–88) and inclusion criteria for SLNB. The melanomas were located as follows: 28 in trunk, 5 in head and neck, 16 in upper limbs and 17 in lower limbs. Three patients had two melanomas. Preoperative lymphoscintigraphy was performed after pericicatricial/perilesional injection of 74 MBq of 99mTc-labeled nanocolloid human serum albumin, obtaining early planar images, late whole body study and sectorial images and SPEC-CT in the area of interest. Planar scintigraphy findings were compared with SPECT-CT. Results: The sentinel node (SN) was localized by planar imaging in 62/63 (98%) patients. SPECT-CT study located the SN in all the patients with a detection rate of 100%. The number of SNs detected with SPECT-CT was higher than that with the planar study in 27 patients. The SPECT-CT provided additional information (change in location and/or in its accuracy in the localization of location uncertain SN) in 14/63 (22.2%) patients, involving changes in the surgical approach and lymph node staging. Conclusion: SPECT-CT detects a higher number of SN than planar lymphoscintigraphy in patients with melanoma. Its contribution is more relevant in the melanomas located on the trunk, head and neck. SPECT-CT modified the SN location by 22% compared to planar scan findings, facilitating a correct surgical approach (AU)

Gastrointestinal neuroendocrine tumors (NETs): new diagnostic and therapeutic challenges.

This paper summarizes the current understanding of the biology of somatostatin receptor (sst), role of immunotherapy in neuroendocrine tumor (NET), new agents for PPRT, and methods to assess response and clinical benefit in NET. One of the most interesting aspects of sst biology is the recent discovery of truncated variants of the sst5 receptor subtype with unique tissue distribution and response to somatostatin (SST). These truncated receptors are associated with bad patient prognosis, decreased response to SST analogs, and may be new targets for diagnoses and treatment. IFN remains a cost-effective agent, particularly in classic mid gut carcinoids, and there is interest to continue examining immunotherapy's in this disease. PRRT remains a key strategy for treatment and imaging. In addition to the classic agents, there are a series of new agents targeting other receptors such as the incretin receptors (GLP-1R; GIPR) and other G-protein coupled receptors with great potential. With regards to therapy monitoring, the most commonly used criteria are Response Criteria Evaluation in Solid Tumors (RECIST). However, for different reasons, these criteria are not very useful in NET. Incorporation of other criteria such as Choi as well as functional imaging assessment with PET would be of great interest in this area.

[Utility of single photon emission computed tomography-computed tomography in selective sentinel lymph node biopsy in patients with melanoma]. / Utilidad de la tomografía de emisión de fotón único-tomografía computarizada en la biopsia selectiva del ganglio centinela en pacientes con melanoma.

OBJECTIVE: To assess the contribution of SPECT-CT lymphoscintigraphy in selective sentinel lymph node biopsy (SLNB) in patients with newly diagnosed malignant melanoma. MATERIAL AND METHODS: A prospective study was made between July 2009 and October 2010. It included 63 patients diagnosed with melanoma (32 men and 31 women) with mean age of 55 years (range: 25-88) and inclusion criteria for SLNB. The melanomas were located as follows: 28 in trunk, 5 in head and neck, 16 in upper limbs and 17 in lower limbs. Three patients had two melanomas. Preoperative lymphoscintigraphy was performed after pericicatricial/perilesional injection of 74MBq of (99m)Tc-labeled nanocolloid human serum albumin, obtaining early planar images, late whole body study and sectorial images and SPECT-CT in the area of interest. Planar scintigraphy findings were compared with SPECT-CT. RESULTS: The sentinel node (SN) was localized by planar imaging in 62/63 (98%) of patients. SPECT-CT study located the SN in all the patients with a detection rate of 100%. The number of SNs detected with SPECT-CT was higher than with the planar study in 27 patients. The SPECT-CT provided additional information (change in location and/or in its accuracy in the localization of location uncertain SN) in 14/63 (22.2%) patients, involving changes in the surgical approach and lymph node staging. CONCLUSION: SPECT-CT detects a higher number of SN than planar lymphoscintigraphy in patients with melanoma. Its contribution is more relevant in the melanomas located on the trunk, head and neck. SPECT-CT modified the SN location by 22% compared to planar scan findings, facilitating a correct surgical approach.

123I-MIBG, 18F-DOPA y 18F-FDG en una paciente con síndrome de neoplasia endocrina múltiple tipo 2 y recidiva de feocromocitoma / 123I-MIBG, 18F-DOPA and 18F-FDG in a patient with MEN2 syndrome and recurrent pheochromocytoma

El feocromocitoma es un tumor poco frecuente localizado en la médula de la glándula adrenal y caracterizado por una elevada síntesis de catecolaminas. La cirugía es el tratamiento de elección y es potencialmente curativa si se diagnostica y reseca adecuadamente. Los métodos de diagnóstico por imagen, tanto morfológica como funcional, son de gran importancia en la evaluación prequirúrgica. Se presenta el caso de una paciente con síndrome de neoplasia endocrina múltiple tipo 2 con suprarrenalectomía bilateral por sendos feocromocitomas y elevación progresiva de la metanefrina urinaria. En la resonancia magnética realizada se observó una imagen nodular en la fosa suprarrenal derecha, por lo que se remitió a nuestra unidad con el objetivo de confirmar la sospecha de recidiva. Dada la ausencia de hallazgos patológicos en la gammagrafía con 123I-MIBG y ante la alta sospecha de recidiva se realizaron estudios PET/TAC con 18F-DOPA y 18F-FDG que confirmaron el diagnóstico(AU)

Pheochromocytoma is a rare tumor located in the medulla of the adrenal gland that is characterized by high catecholamine synthesis. Surgery is the treatment of choice and is usually curative if appropriately diagnosed and excised. Imaging methods, both morphological and functional, are of great importance in presurgical evaluation. We report the case of a female patient with multiple endocrine neoplasia syndrome type 2, with bilateral adrenalectomy due to two pheochromocytomas and progressive elevation of urinary metanephrine. Magnetic resonance imaging showed a nodular image in the right adrenal fossa. The patient was referred to our unit in order to confirm suspicion of recurrence. Due to the absence of pathological findings in the 123I-MIBG scintigraphy and high suspicion of recurrence, PET/CT imaging with 18F-DOPA and 18F-FDG were performed, and the diagnosis was confirmed(AU)

Efectividad e impacto clínico de la PET- 18F-FDG en el diagnóstico de segundos tumores primarios insospechados / Effectivity and clinical impact of 18F-FDG-PET in the diagnosis of unsuspected second primary tumors

Objetivo. Evaluar la capacidad e impacto clínico de la PET-18F-FDG en el diagnóstico de segundos tumores primarios malignos inesperados. Material y métodos. Estudio retrospectivo transversal descriptivo de 1.984 exploraciones PET-18F-FDG consecutivas realizadas entre marzo de 2004 y marzo de 2005, identificándose aquellos estudios en los que se había informado de la presencia de lesiones hipermetabólicas, no sospechadas ni detectadas previamente y que pudiesen ser sugestivas de segundos tumores primarios. Se obtuvo un diagnóstico histopatológico o mediante seguimiento clínico-radiológico durante un período de tiempo superior a un año. Resultados. Se detectaron 62 hallazgos sugestivos de incidentalomas en 58 pacientes (3,1%). Los motivos de indicación en este grupo de pacientes fueron diversos siendo los más frecuentes el diagnóstico diferencial de benignidad vs malignidad de nódulos pulmonares solitarios. Un 43,5% de las lesiones no tuvieron seguimiento. Se confirmó la existencia de 35 lesiones, bien mediante estudio anatomopatológico (21 lesiones, 13 incidentalomas, la incidencia en nuestra población fue del 0,65%) o por seguimiento clínico-radiológico (14 lesiones, ninguna de ellas correspondió a segundos tumores primarios). El impacto clínico total fue el hallazgo de 14 lesiones no esperadas en 12 pacientes. Conclusiones. La presencia de incidentalomas en la PET-18F-FDG es relativamente frecuente. Estas lesiones deben ser objeto de seguimiento clínico para su diagnóstico exacto. En un alto porcentaje se corresponden con segundos tumores primarios inesperados en fase incipiente y, por lo tanto, susceptibles de tratamiento curativo o que pueden modificar la planificación del tratamiento del tumor ya conocido(AU)

Objective. This study has aimed to determine the capacity and clinical impact of the 18F-FDG-PET to detect previously unsuspected second primary tumors. Material and Methods. This is a retrospective cross-sectional study of 1984 consecutive scans performed between March 2004 and March 2005, identifying those studies that had reported the presence of hypermetabolic lesions, that had not been previously suspected or detected and that could be suggestive of second primary tumors. Diagnosis was made histopathologically or by clinical and radiological follow-up for a period exceeding one year. Results. 62 findings suggestive of second primary tumors were detected in 58 patients (3.1%). The reasons for the study for this group of patients were diverse, the most common being the differential diagnosis of solitary pulmonary nodules. A total of 43.5% of lesions were not followed-up. We confirmed the existence of 35 lesions, either by pathology study (21 lesions, 13 second primary tumors, the incidence in our population was 0.65%) or clinical and radiological follow-up (14 lesions, none of which corresponded to second primary tumors). The total clinical impact was the discovery of unexpected 14 lesions in 12 patients. Conclusion. The presence of second primary tumors on 18F-FDG-PET is relatively common. These lesions should be monitored clinically for accurate diagnosis. In a high percentage, they correspond to unexpected second primary tumors in an early stage and therefore amenable to curative treatment or for which tumor treatment planning may be modified(AU)

[Elaboration of the SPM template for the standardization of SPECT images with 123I-Ioflupane]. / Elaboración de una plantilla de SPM para la normalización de imágenes de SPECT con 123I-Ioflupano.

PURPOSE: Statistical parametric mapping (SPM) is a widely used produced for normalization of functional images. This study has aimed to develop a normalization template of (123)I-Ioflupane SPECT-imaging DaTSCAN(®), GE Healthcare), not available in SPM5, and to validate it compared to other quantification methods. MATERIAL AND METHODS: In order to write the template we retrospectively selected 26 subjects who had no evidence of nigrostriatal degeneration and whose age distribution was similar to that of the patients in the usual practice of our Department: 2 subjects (7.6%) were < 35 years, 9 between 35-65 years (34.6%) and 15 > 65 years (57.7%). All the studies were normalized with the T1-template available in SPM5 and an average image of the value was obtained for each voxel. For validation we analyzed 60 patients: 30 with idiopathic Parkinson's disease patients (iPD) with right involvement (66.83±12.20 years) and 30 with essential tremor patients (ET) (67.27±8.33 years). Specific uptake rates (SUR) of different striatal regions were compared after image normalization with our template and the application of a semiautomated VOIs-map created with Analyze v9.0 ((©)BIR, Mayo Clinic), against two quantification methods: a) manual adjustment of a ROIs-map drawn in Analyze, and b) semi-automated method (HERMES-BRASS) with normalization and implementation of VOIs-map. RESULTS: No statistically significant differences in the iPD/ET discriminatory capacity between the three methods analyzed were observed (p<0,001). The correlation of SUR after normalization with our «template¼ was higher than that obtained by method b) (R>0,871, p<0,001). This difference was greater in patients with PD. CONCLUSIONS: Our study demonstrates the efficacy of our SPM «template¼ for (123)I-Ioflupane SPECT-imaging, obtained from normalization with «T1-template¼.

Hallazgo incidental de un tumor carcinoide bronquial en gammagrafía de receptores de somatostatina de paciente con síndrome de neoplasia endocrina múltiple tipo 1 e hipergastrinemia / Unsuspected bronchial carcinoid tumor detected in a somatostatin receptor scintigraphy in a patient with multiple endocrine neoplasia syndrome type 1 and hypergastrinemia

El síndrome de neoplasia endocrina múltiple tipo 1 (MEN 1) se caracteriza por la presencia de neoplasias en glándulas paratiroides, hipófisis anterior, páncreas endocrino y duodeno. Sin embargo, otro tipo de tumores también se pueden presentar. Uno de ellos es el tumor carcinoide, que en este contexto, se localiza más frecuentemente en el tracto gastrointestinal. Menos frecuente es la aparición de tumores carcinoides de origen bronquial que, con confirmación histológica se pueden presentar en el 5-8% de los casos y que se han encontrado con más frecuencia en pacientes que cursan con hipergastrinemia. Presentamos el caso de un paciente con antecedente de síndrome MEN 1, hipergastrinemia y el hallazgo incidental en un estudio gammagráfico de receptores de somatostatina de un tumor carcinoide bronquial confirmado histológicamente (AU)

Multiple Endocrine Neoplasia type 1 syndrome (MEN1) is characterized by the presence of tumors in parathyroid glands, anterior pituitary gland, endocrine pancreas and duodenum. However, other tumors may also occur. One of them is the carcinoid tumor, which in this context, is more common in the gastrointestinal tract. Less common is the presence of carcinoid tumors of bronchial origin, which with histologic confirmation, may occur in 5-8% of cases and that appears more frequently in patients with hypergastrinemia. We report a patient with MEN1 syndrome, hypergastrinemia and an incidental finding in a somatostatin receptor scintigraphy of an unsuspected bronchial carcinoid tumor that was confirmed histologically (AU)

123I-MIBG, 18F-DOPA and 18F-FDG in a patient with MEN2 syndrome and recurrent pheochromocytoma.

Pheochromocytoma is a rare tumor located in the medulla of the adrenal gland that is characterized by high catecholamine synthesis. Surgery is the treatment of choice and is usually curative if appropriately diagnosed and excised. Imaging methods, both morphological and functional, are of great importance in presurgical evaluation. We report the case of a female patient with multiple endocrine neoplasia syndrome type 2, with bilateral adrenalectomy due to two pheochromocytomas and progressive elevation of urinary metanephrine. Magnetic resonance imaging showed a nodular image in the right adrenal fossa. The patient was referred to our unit in order to confirm suspicion of recurrence. Due to the absence of pathological findings in the (123)I-MIBG scintigraphy and high suspicion of recurrence, PET/CT imaging with (18)F-DOPA and (18)F-FDG were performed, and the diagnosis was confirmed.

[Unsuspected bronchial carcinoid tumor detected in a somatostatin receptor scintigraphy in a patient with multiple endocrine neoplasia syndrome type 1 and hypergastrinemia]. / Hallazgo incidental de un tumor carcinoide bronquial en gammagrafía de receptores de somatostatina de paciente con síndrome de neoplasia endocrina múltiple tipo 1 e hipergastrinemia.

Multiple Endocrine Neoplasia type 1 syndrome (MEN1) is characterized by the presence of tumors in parathyroid glands, anterior pituitary gland, endocrine pancreas and duodenum. However, other tumors may also occur. One of them is the carcinoid tumor, which in this context, is more common in the gastrointestinal tract. Less common is the presence of carcinoid tumors of bronchial origin, which with histologic confirmation, may occur in 5-8% of cases and that appears more frequently in patients with hypergastrinemia. We report a patient with MEN1 syndrome, hypergastrinemia and an incidental finding in a somatostatin receptor scintigraphy of an unsuspected bronchial carcinoid tumor that was confirmed histologically.

[Effectivity and clinical impact of (18)F-FDG-PET in the diagnosis of unsuspected second primary tumors]. / Efectividad e impacto clínico de la PET-(18)F-FDG en el diagnóstico de segundos tumores primarios insospechados.

OBJECTIVE: This study has aimed to determine the capacity and clinical impact of the (18)F-FDG-PET to detect previously unsuspected second primary tumors. MATERIAL AND METHODS: This is a retrospective cross-sectional study of 1984 consecutive scans performed between March 2004 and March 2005, identifying those studies that had reported the presence of hypermetabolic lesions, that had not been previously suspected or detected and that could be suggestive of second primary tumors. Diagnosis was made histopathologically or by clinical and radiological follow-up for a period exceeding one year. RESULTS: 62 findings suggestive of second primary tumors were detected in 58 patients (3.1%). The reasons for the study for this group of patients were diverse, the most common being the differential diagnosis of solitary pulmonary nodules. A total of 43.5% of lesions were not followed-up. We confirmed the existence of 35 lesions, either by pathology study (21 lesions, 13 second primary tumors, the incidence in our population was 0.65%) or clinical and radiological follow-up (14 lesions, none of which corresponded to second primary tumors). The total clinical impact was the discovery of unexpected 14 lesions in 12 patients. CONCLUSION: The presence of second primary tumors on (18)F-FDG-PET is relatively common. These lesions should be monitored clinically for accurate diagnosis. In a high percentage, they correspond to unexpected second primary tumors in an early stage and therefore amenable to curative treatment or for which tumor treatment planning may be modified.

Valor de la PET-FDG negativa en el seguimiento a medio plazo del carcinoma diferenciado de tiroides en pacientes con rastreo con 131I-Na negativo y cifras de tiroglobulina elevadas / Value of the negative PET-FDG in the middle term follow-up of differentiated thyroid cancer in patients with negative 131I-Na scan and elevated thyroglobulin serum levels

Objetivo. Pretendemos analizar la evolución de los pacientes diagnosticados de carcinoma diferenciado de tiroides (CDT) con un rastreo de cuerpo completo con 131I-Na (RCC) negativo, una tiroglobulina sérica (Tg) elevada y una tomografía por emisión de positrones con 18F-fluordeoxiglucosa (PET-FDG) negativa. Material y métodos. Se estudiaron retrospectivamente a 23 pacientes diagnosticados y tratados de CDT, con edades comprendidas entre los 23 y 83 años, que entre enero de 2001 y diciembre de 2002 presentaron, un RCC negativo con valores de Tg en un rango de sospecha de recurrencia o metástasis (Tg > 2 ngr/mL con supresión de tratamiento hormonal) y una PET-FDG negativa. Tras un seguimiento clínico, radiológico y analítico de estos pacientes durante un periodo mínimo de 4 años, se vuelve a evaluar el estado de enfermedad con un RCC de control, observando a su vez la evolución de la Tg. Todos los RCC se realizaron con dosis diagnósticas de 185 MBq de 131I-Na. Resultados. En 18 de los 23 pacientes la Tg descendió y en 5 ascendió. Cuatro pacientes (17%) estaban libres de enfermedad (RCC negativo y Tg < 2 ngr/mL). Dieciséis pacientes (70%) estaban libres de enfermedad según el RCC pero con cifras elevadas de Tg. En 3 pacientes (13%) se observó enfermedad y cifras elevadas de Tg, 2 con RCC positivo y el tercero con 99mTc-MIBI y TC positivos. Conclusiones. La mayoría de los pacientes con RCC negativo, Tg elevada y PET-FDG negativa muestran una buena evolución, descendiendo los niveles de Tg e incluso alcanzando valores de normalidad en un porcentaje significativo de ellos(AU)

Objective. This study has aimed to analyze the evolution of patients diagnosed with differentiated thyroid carcinoma (DTC) with a negative 131I-Na whole body scan (WBS), high levels of serum thyroglobulin (Tg) and negative 18Ffluorodeoxyglucose positron emission tomography (PET-FDG) study. Material and methods. Twenty-three patients diagnosed and treated for DTC were studied retrospectively. Patients were aged between 23 and 83 and had shown, between January 2001 and December 2002, negative WBS, Tg values in a range of suspected recurrence or metastasis (Tg>2 ng / mL with thyroid hormone withdrawal) and a negative PET-FDG study. The patients were monitored clinically, radiologically and analytically for a minimum period of 4 years. After this, a new evaluation was made of their state of disease with a control WBS, also observing the evolution of Tg. All WBS were performed with a 185 MBq diagnostic dose of 131I-Na. Results. In 18/23 patients, Tg decreased and in 5 it increased. Four patients (17%) were free of active disease (negative WBS Tg<2 ng / mL). A total of 16 patients (70%) were free of disease according to the WBS but had elevated Tg. Three patients (13%) had disease and high levels of Tg, two of them with positive WBS and the third with 99mTc-MIBI scan and CT positive. Conclusions. Most patients with a negative WBS, high Tg serum levels and negative FDG PET had good evolution, with descending Tg levels, normal levels even being reached in a significant percentage of them(AU)

Value of the negative PET-FDG in the middle term follow-up of differentiated thyroid cancer in patients with negative 131 I-Na scan and elevated thyroglobulin serum levels.

OBJECTIVE: This study has aimed to analyze the evolution of patients diagnosed with differentiated thyroid carcinoma (DTC) with a negative (131)I-Na whole body scan (WBS), high levels of serum thyroglobulin (Tg) and negative (18F)fluorodeoxyglucose positron emission tomography (PET-FDG) study. MATERIAL AND METHODS: Twenty-three patients diagnosed and treated for DTC were studied retrospectively. Patients were aged between 23 and 83 and had shown, between January 2001 and December 2002, negative WBS, Tg values in a range of suspected recurrence or metastasis (Tg>2 ng / mL with thyroid hormone withdrawal) and a negative PET-FDG study. The patients were monitored clinically, radiologically and analytically for a minimum period of 4 years. After this, a new evaluation was made of their state of disease with a control WBS, also observing the evolution of Tg. All WBS were performed with a 185 MBq diagnostic dose of (131)I-Na. RESULTS: In 18/23 patients, Tg decreased and in 5 it increased. Four patients (17%) were free of active disease (negative WBS Tg<2 ng / mL). A total of 16 patients (70%) were free of disease according to the WBS but had elevated Tg. Three patients (13%) had disease and high levels of Tg, two of them with positive WBS and the third with (99m)Tc-MIBI scan and CT positive. CONCLUSIONS: Most patients with a negative WBS, high Tg serum levels and negative FDG PET had good evolution, with descending Tg levels, normal levels even being reached in a significant percentage of them.

[Evaluation of efficacy and clinical impact of 18F-FDG-PET in the diagnosis of recurrent medullary thyroid cancer with increased calcitonin and negative imaging test]. / Evaluación de la eficacia y del impacto clínico de la PET-18F-FDG en el diagnóstico de recurrencia del carcinoma medular de tiroides con calcitonina elevada y pruebas de imagen negativas.

AIM: To evaluate the efficacy and clinical impact of the FDG-PET in the diagnosis of suspicion of recurrence of medullary thyroid cancer (MTC) in patients with elevated serum calcitonin and negative imaging test. MATERIAL AND METHODS: We performed a retrospective study of 31 consecutive cases from february 2001 to october 2007 of 17 women and 14 men, mean age 56.2 years (range: 26-88), with anatomical-pathology diagnosis of medullary thyroid cancer and suspicion of recurrence due to abnormal elevation of calcitonin and negative imaging tests. All of the patients underwent whole body FDG-PET scan with a dedicated PET or PET-CT 60 minutes after intravenous injection of 333-434 MBq of (18)F-FDG. Results were confirmed by pathology study in 45.2% of the patients and by clinical follow-up with a mean of 4 years (range: 16 m-8 years) RESULTS: Sensitivity was 88%, specificity 84.6%, positive predictive value 88%, negative predictive value 84.6% and diagnostic accuracy 87%. The results of the FDG PET modified the therapeutic strategy in 14 cases (45.2%). A comparison was made of the mean values of calcitonin using the Student's "t" test between positive PET studies for the disease and negative ones. No significant differences were found (P=.3). CONCLUSIONS: In patients with MTC and suspected recurrence with elevated calcitonin and negative imaging test, the FDG is the best test for the diagnosis of occult recurrence in MTC with elevated calcitonin and negative imaging techniques with elevated clinical impact. It facilitates the therapeutic management of the patients with MTC recurrence, and should be included in the diagnosis algorithm in these patients.

Uso de la PET-18F-FDG en pacientes con sospecha de recurrencia de cáncer diferenciado de tiroides por anticuerpos anti-tiroglobulina elevados y rastreo 131I negativo / Use of 18FFDG-PET in patients with suspicion of recurrent differentiated thyroid cancer by elevated antithyroglobulin antibodies levels and negative 131I scan

Objetivo. Valorar la utilidad de los estudios PET-18F-FDG en el seguimiento de los pacientes diagnosticados de carcinoma diferenciado de tiroides que presentan riesgo de enfermedad y niveles de tiroglobulina (Tg) no interpretables por la presencia de anticuerpos antitiroglobulina (AbTg). Material y métodos. Estudio retrospectivo de 7 mujeres con edad media de 40 años y diagnóstico histológico de cáncer diferenciado de tiroides (7 carcinomas papilares) que fueron remitidos a nuestro servicio para la realización de estudio PET-18F-FDG por sospecha de enfermedad, debido a rastreo 131I negativo y niveles de AbTg elevados, entre los años 2002 y 2007. Se les realizaron 11 exploraciones PET tras la inyección de 370-434 MBq de 18F-FDG en condiciones de normoglucemia y previa administración de relajante muscular, hidratación y furosemida. Los resultados de la PET se confirmaron por histología y/o por evolución clínico radiológica, con un período de seguimiento mínimo de 24 meses. Resultados. La prevalencia de la recurrencia de la enfermedad en la población estudiada fue del 57,14%. Todas las pacientes presentaban niveles de Tg inferiores a 3 ng/dl y AbTg superiores a 200 UI/ml. Tres pacientes presentaban antecedentes de tiroiditis. De los 11 estudios realizados la PET fue negativa en tres y positiva en 8. Se descartó la existencia de enfermedad en 3 pacientes mientras que en 4 pacientes la PET permitió localizar con éxito la existencia de recidiva. Conclusión. La PET-18F-FDG es una técnica útil para localizar enfermedad, así como para descartar la existencia de recurrencia con una elevada seguridad diagnóstica, en pacientes con antecedentes de carcinoma diferenciado de tiroides con rastreo 131I negativo, pero con elevación patológica de anticuerpos AbTg(AU)

Aim. To evaluate the utility of 18FFDG-PET for patients diagnosed of differentiated thyroid carcinoma who present risk of disease and invaluable levels of thyroglobulin (Tg) by the presence of antibodies antithyroglobulin (AbTg). Material and methods. Retrospective study of 7 women of 40 years old and histological diagnosis of differentiated thyroid cancer (7 papillary tumours) that were sent to our department for the accomplishment of18FFDG-PET study because of suspicion of disease, due to 131I negative and high levels of AbTg, between the year 2002 and 2007. 11 PET scans were obtained after the intravenous injection of 370-434 MBq of 18FFDG in normoglycemia conditions and previous administration of muscle relaxant, hydration and diuretic. The results of 18FFDG-PET scans were confirmed by pathologic examination or clinical outcome and radiographic examination for more than 24 months. Results. The prevalence of recurrence in our population was 57.14%. All patients presented levels of Tg lower than 3 ng/dl and AbTg superior to 200 UI/ml. Three patients had precedent thyroiditis. Out of 11 scans performed 3 of them were negative and 8 cases were found positive. It ruled out the existence of disease in three patients and localized the presence of recurrence in 4 patients. Conclusion. 18FFDG-PET Conclusion. CONCLUSION: 18F-FDG-PET is a useful diagnostic tool for the detection of recurrence as well as to rule out the existence of disease with a high accuracy, in patients with differentiated thyroid carcinoma with 131I whole body scan negative but with pathological elevation of antithyroglobulin antibodies(AU)

[Use of 18F FDG-PET in patients with suspicion of recurrent differentiated thyroid cancer by elevated antithyroglobulin antibodies levels and negative ¹³¹I scan]. / Uso de la PET-18F-FDG en pacientes con sospecha de recurrencia de cáncer diferenciado de tiroides por anticuerpos anti-tiroglobulina elevados y rastreo ¹³¹I negativo.

AIM: To evaluate the utility of (18F)FDG-PET for patients diagnosed of differentiated thyroid carcinoma who present risk of disease and invaluable levels of thyroglobulin (Tg) by the presence of antibodies antithyroglobulin (AbTg). MATERIAL AND METHODS: Retrospective study of 7 women of 40 years old and histological diagnosis of differentiated thyroid cancer (7 papillary tumours) that were sent to our department for the accomplishment of(18F)FDG-PET study because of suspicion of disease, due to ¹³¹I negative and high levels of AbTg, between the year 2002 and 2007. 11 PET scans were obtained after the intravenous injection of 370-434 MBq of (18F)FDG in normoglycemia conditions and previous administration of muscle relaxant, hydration and diuretic. The results of (18F)FDG-PET scans were confirmed by pathologic examination or clinical outcome and radiographic examination for more than 24 months. RESULTS: The prevalence of recurrence in our population was 57.14%. All patients presented levels of Tg lower than 3 ng/dl and AbTg superior to 200 UI/ml. Three patients had precedent thyroiditis. Out of 11 scans performed 3 of them were negative and 8 cases were found positive. It ruled out the existence of disease in three patients and localized the presence of recurrence in 4 patients. CONCLUSION: (18F)FDG-PET CONCLUSION: 18F-FDG-PET is a useful diagnostic tool for the detection of recurrence as well as to rule out the existence of disease with a high accuracy, in patients with differentiated thyroid carcinoma with ¹³¹I whole body scan negative but with pathological elevation of antithyroglobulin antibodies.