NP-59 test for preoperative localization of primary hyperaldosteronism.

PURPOSE: Adrenal venous sampling is generally considered the gold standard to identify unilateral hormone production in cases of primary hyperaldosteronism. The aim of this study is to evaluate whether the iodine-131-6-ß-iodomethyl-19-norcholesterol (NP-59) test may represent an alternative in selected cases. METHODS: Patients submitted to laparoscopic adrenalectomy for suspected primary hyperaldosteronism (n = 27) were retrospectively reviewed. When nuclear medicine tests were preoperatively performed, their results were compared with the histopathologic findings and clinical improvement. RESULTS: Nuclear medicine tests were realized in 13 patients. In 11 (84.6%), a planar anterior and posterior NP-59 scintigraphy was performed and a SPECT/TC in two (15.4%). Scintigraphy indicated a preoperative lateralization in 12 out of 13 patients (92.3%). When the value of NP-59 tests was based on pathologic results, it showed a sensitivity of 90.9% and a positive predictive value of 83.3%. When the nuclear medicine test's performance was based on postoperative blood pressure control, both sensitivity and positive predictive value were 91.6%. CONCLUSIONS: Nuclear medicine tests represent a useful tool in the preoperative localisation of primary hyperaldosteronism with a high sensitivity and positive predictive value. In patients with contraindications to adrenal venous sampling like contrast allergies, or when it is inconclusive, scintigraphy can represent a useful and non-invasive alternative.

Update in imaging tests used for the localization of parathyroid pathology.

Preoperative localization of parathyroid pathology, generally a parathyroid adenoma, can be difficult in some cases due to the anatomical variants that these glands present. The objective of this review is to analyse the different imaging techniques used for preoperative localization of parathyroid pathology (scintigraphy, ultrasound, CT, MRI and PET). There is great variability between the different tests for the preoperative localization of parathyroid pathology. The importance of knowing the different diagnostic options lies in the need to choose the most suitable test at each moment and for each patient for an adequate management of primary hyperparathyroidism (PHP) with surgical criteria.

Preoperative parathyroid localization. Relevance of MIBI SPECT-CT in adverse scenarios.

PURPOSE: Selective parathyroidectomy, the treatment of choice for primary hyperparathyroidism, requires precise preoperative localization. Our purpose was to compare the accuracy and concordance of pre-surgical MIBI parathyroid scintigraphy and ultrasonography, as well as to assess the relevance of hybrid acquisition (SPECT/CT) in compromised circumstances: low-weight or ectopic adenomas, coexisting thyroid disease and re-interventions. METHODS: The study included 223 patients with primary hyperparathyroidism operated in a single Surgical Unit from August 2016 to March 2021. Preoperative ultrasonography and double-phase MIBI were performed with early SPECT/CT acquisition. A minimally invasive surgical approach was initially attempted, except in patients with concomitant thyroid surgery or multiglandular parathyroid disease. RESULTS: Selective parathyroidectomy was accomplished in 179 patients (80.2%); cervicotomy and/or thoracoscopy in 44. Removal of the parathyroid lesion was achieved in 211 patients (94.6%), corresponding 204 (96.7%) to adenomas (37 ectopic). The cure rate was 94.2%. Preoperative MIBI SPECT/CT showed higher sensitivity and accuracy (84%; 80%) compared to ultrasound (72%; 71%), being more precise in defining the exact anatomical location (75.8% vs 68.7%). These differences reached statistical significance in ectopic glands. The existence of concomitant thyroid pathology did not decrease the sensitivity of SPECT/CT (84.2%). Mean parathyroid weight was 692.2mg (95%CI: 443.5-941) in MIBI-negative cases and 1145.9mg (95%CI: 983.6-1308.3) in MIBI-positive (p=0.001). Re-intervention was successful in the 8 patients with previous surgery. CONCLUSION: MIBI SPECT/CT presents greater sensitivity, accuracy and anatomical precision than ultrasound for preoperative parathyroid localization, even in the case of ectopic glands or coexisting thyroid pathology. The weight of the pathological gland is a significantly limiting factor.

Absolute quantification of myocardial uptake of 99mTc-DPD in patients with cardiac amyloidosis due to transthyretin deposits (ATTR).

PURPOSE: To determine the diagnostic contribution of the absolute quantification of the myocardial deposit of 99mTc-DPD in patients with cardiac amyloidosis due to transthyretin deposits (ATTR). MATERIALS AND METHODS: SPECT/CT was performed in 41 patients with positive scintigraphic results for ATTR cardiac amyloidosis. The patients were divided into two groups (Perugini grades 2 and 3) and the SUVmax at the level of the bone and both ventricles and the percentage of dose calculated in these areas were calculated. The Student's t-test was used to compare results and the area under the curve (AUC) was calculated to assess differential efficacy and establish discriminatory cut-off points between both groups of patients. RESULTS: Statistically significant differences were observed in all the study variables, with the exception of bone SUVmax. The differences with the greatest statistical power were observed in the variables SUVmaxRV and the percentage of dose in both ventricles (p < 0.001). The cut-off point obtained for the variable SUVmaxLV was 8.620 (sensitivity 87.9% and specificity 100%; AUC 0.966), while that of the variable SUVmaxRV was 6.195 (sensitivity 81.8% and specificity 100%; AUC 0.955). CONCLUSIONS: The absolute quantification of myocardial uptake of 99mTc-DPD in the SPECT/CT images of patients with suspected cardiac amyloidosis due to transthyretin deposits represents a new diagnostic tool that allows adequate classification of patients according to the Perugini visual grading scale.

In-vivo lymphoscintigraphy of sinonasal tumors identifies retropharyngeal node and level I as predominant sentinel nodes.

OBJECTIVE: To evaluate by in- vivo lymphoscintigraphy and SPECT-CT imaging, the lymphatic drainage patterns of para-nasal sinus(PNS) tumors. To confirm or refute the belief of the retropharyngeal lymph node (RPLN) being the significant draining lymph node for such tumors. METHODS: Prospective cohort study conducted on previously untreated PNS tumors with no clinico-radiological evidence of lymph node metastasis. Lymphoscintigraphy undertaken by nasal endoscopic assisted peritumoral injection of 99mTc Sulfur colloid. Injections were classified as anterior or posterior as per a vertical line along the maxillary sinus ostium. RESULTS: 17 patients were included. Lymphoscintigraphy successfully identified 17 sentinel nodes in 15 patients and was unsuccessful (lymphoscintigraphy failure) in 2 patients. Predominant sites of sentinel lymphatic drainage were noted to be the RPLN (n = 8; 47%), and Level I (n = 7; 42%). Occasional drainage was identified at the peri-parotid node(n = 1) and at Level II (n = 1). Contralateral drainage was noted in 2 patients (level I-1 and RPLN-1). Anterior injections drained predominantly to Level I (6/8) and RPLN (2/8), while posterior injections drained predominantly to the RPLN ( 6/7). The relative risk of RPLN being identified as the sentinel node was significantly higher for posteriorly placed injections than for anteriorly placed injections (RR- 3.43; 95% CI-1.0-11.8, p = 0.05). CONCLUSION: The RPLN is noted as a frequent draining node for sino-nasal tumours and merits routine attention in all sino-nasal tumors. The radio-colloid SPECT-CT technique described here offers an excellent in-vivo technique to further explore and validate the lymphatic drainage pathways of these tumours.

Contributions of nuclear medicine to malignant musculoskeletal tumor disease in children.

A diagnosis of cancer is frightening at any age, but especially when the patient is a child. Only what is suspected can be diagnosed, only what is known or at least known to exist is suspected, but musculoskeletal tumors are infrequent and therefore very difficult to diagnose or treat. Probably due to their infrequency, the complexity of the radiological images, histopathological appearance, as well as the serious consequences due to inadequate biopsies and treatments, musculoskeletal tumor pathology requires clinical management that must be carried out by a group of specialists with specific training, allowing an adequate diagnosis, introduction of adjuvant therapies, as well as surgical treatment, making multidisciplinary treatment essential today. Imaging studies provide essential information on the nature of each lesion, its size, its anatomical location, the effect on the surrounding bone or soft tissues and the involvement of adjacent joints and neurovascular structures. In this article the authors will discuss the advances in nuclear medicine techniques (scintigraphy, SPECT/CT and PET/CT) and their usefulness in the staging of pediatric malignant musculoskeletal tumors, as well as in the assessment of response, follow-up, and diagnosis of recurrence.

Determination of the segmental hepatic clearance rate of 99mTc-mebrofenin and its application in the functional assessment of future liver remnant after liver resection.

99mTc-mebrofenin hepatobiliary scintigraphy with SPECT/CT (HBS-M) has become an important quantitative method to evaluate global liver function and future liver remnant (FLR) function in patients who are candidates for resective liver surgery. The purpose of this work was to describe the method in the prediction of post-surgical liver failure. The overall liver function and that of the FLR are obtained by analysis of the initial dynamic phase of the scan. Liver volume to be preserved is expressed as a percentage of the total liver volume measured in both CT sections. HBS-M is able to accurately gauge regional liver function abnormalities that could be represented as normal liver tissue parenchyma in the CT study. This technique can provide very valuable prognostic information for the estimation of the postoperative risk of liver failure in all patients who are candidates for resective liver surgery.

Nuclear Medicine in the diagnosis of pathologies of the spine: role of hybrid imaging. / Medicina nuclear en el diagnóstico de las afecciones de la columna vertebral: papel de la imagen híbrida.

Clinical problems in the human spine are still common in our society, often causing pain and can also limit movement. Back pain is a very common clinical entity, although difficult to diagnose due to its multifactorial nature. There are multiple processes that can alter the structure of the spine, injure vertebrae and/or the surrounding tissue. For the study of the spine, image diagnosis is essential, and within this, molecular hybrid techniques play an important role by providing us with an image of functional and morphological fusion. Among these, SPECT/CT is key in the diagnosis of traumatic and stress pathology, allowing us to locate hidden vertebral fractures, and is also very useful in degenerative and post-surgical pathology. On the other hand, PET/CT with 18F-FDG also plays an important role in the management and monitoring of infectious and oncological processes. This review describes the application of these hybrid techniques in the different pathologies of the spine and the findings of their images, being very useful for the diagnostic assessment and therapeutic management of the patient.

Preparation, radiolabeling with 99mTc and 67Ga and biodistribution studies of albumin nanoparticles covered with polymers. / Preparación, radiomarcaje con 99mTc y 67Ga y estudios de biodistribución de nanopartículas de albúmina con recubrimientos poliméricos.

OBJECTIVE: To optimize radiolabeling with 99mTc and 67Ga of albumin nanoparticles coated with 4 differents synthetic polymers and to evaluate their stability in vivo and in vitro, as well as their biodistribution in vivo after intravenous administration. MATERIAL AND METHODS: The nanoparticles were prepared using albumin and NOTA-modified albumin by the desolvation method and coated with 4 different polymers; HPMC, GMN2, GPM2 and GTM2. They were purified, lyophilized and characterized. Radiolabelling with 99mTc was perfomed with 74 MBq of 99mTc sodium pertechnetate, previously reduced with and acid solution of tin chloride at different concentrations (0.003, 0.005, 0.007, 0.01, 0.05 and 0.1mg/ml) and at different times (5, 10, 15, 30 and 60minutes) and temperatures (room temperature, 40°C and 60°C). Radiolabelling with 67Ga was perfomed by incubation of the nanoparticles with 37 MBq of 67Gallium chloride (obtained from commercial gallium-67 citrate) at different times (10 and 30minutes) and temperatures (room temperature, 30°C and 60°C), and posterior purification with microconcentrators. The radiochemical purity was evaluated by TLC. Stability studies of radiolabeled nanoparticles in physiological serum and blood plasma were perfomed. Biodistribution studies of nanoparticles coated with GPM2 polymer were carried out in Wistar rats after intravenous administration of the nanoparticles. Control animals were carried out with 99mTc sodium pertechnetate and 67Ga chloride. To do so, the animals were killed and activity in organs was measured in a gamma counter. RESULTS: 99mTc labeling was carried out optimally with a tin concentration of 0.007mg/ ml for the GPM2 nanoparticles and 0.005mg / ml for the rest of the formulations, with a radiolabelling time of 10minutes at room temperature. In the case of 67Ga the label was optimized at 30° C temperature and 30minutes of incubation. In both cases the radiochemical purity obtained was greater than 97%. The nanoparticles showed high stability in vitro after 48hours of labeling (70% nanoparticles labeled with 99mTc and 90% those labeled with 67Ga). Biodistribution studies of nanoparticles 99mTc -GPM2 and 67Ga -NOTA-GPM2 showed a high accumulation of activity in the liver at 2 and 24hours after intravenous administration. CONCLUSION: The labeling procedure with 99mTc and 67Ga of albumin and albumin modified with NOTA nanoparticles allows obtaining nanoparticles with high labeling yields and adequate in vitro stability, allowing their use for in vivo studies.

99mTC-white blood cell scintigraphy with SPECT/CT in the diagnosis of vascular graft infection. / Gammagrafía con leucocitos marcados y SPECT/TC en el diagnóstico de infección de prótesis vasculares.

AIM: Vascular graft infection is a rare complication with a high morbidity and mortality. Early diagnosis is essential to establish an adequate treatment. We assess the accuracy of 99mTc-WBC scintigraphy with SPECT/CT in the diagnosis of vascular graft infection. MATERIALS AND METHODS: We retrospectively analyzed thirty 99mTc-WBC scintigraphies with SPECT/CT performed in thirty patients with suspicion of vascular prosthesis infection. Studies were considered positive for graft infection if the intensity of activity involving the graft was greater than the liver or bone marrow activity (spine and pelvis). RESULTS: Final diagnosis of infection was established in 10 patients, based on Fitzgerald criteria. Scintigraphy was positive in 11 patients. No false negatives were obtained. The values of sensitivity and specificity were 100% and 95%, respectively, with a PPV of 91% and a NPV of 100%. Twenty five patients had a CT performed prior to scintigraphy, in 9 cases the result was positive and in the remaining 16 was negative. CT sensitivity and specificity obtained in our study were 62.5% and 76% respectively, with a PPV of 55.6% and a NPV of 81.3%. Diagnosis of infection led to prosthesis exeresis in 8 cases (all of them had a positive microbiological study of the extracted material), while the remaining 2 patients were treated with antibiotic therapy alone due to high surgical risk. CONCLUSION: Our results suggest a high accuracy for 99mTc-WBC scintigraphy with SPECT/CT in the assessment of clinically suspected arterial graft infection.

Clinical applications of nuclear medicine in the diagnosis and assessment of musculoskeletal sports injuries. / Aplicaciones clínicas de la medicina nuclear en el diagnóstico y evaluación de las lesiones deportivas musculoesqueléticas.

Increased participation in sports and physical exercise are widely promoted as an approach to a physically active lifestyle which has a positive effect on healthy aging, in patients and athletes of all ages, beginners and experts, including amateur athletes and professional athletes. Unfortunately, this has caused a higher incidence of sports-related injuries. In the sports context, the early and accurate diagnosis of injuries is of the utmost importance in order to enable early treatment to achieve a full recovery. Imaging techniques are increasingly important for the successful diagnosis and management of the patient. The nuclear medicine techniques with bone tracers provide physiological and metabolic information in the early phases of musculoskeletal injuries, which often precede anatomical changes and they reflect changes in bone turnover. This allows early diagnosis, along with evaluation of the activity and phase of the injury. In this article, the applications of nuclear medicine techniques, focusing on bone scintigraphy, alongside the important contribution of hybrid studies (SPECT/CT), in the diagnosis of bone and soft tissue sports injuries, will be described. In addition, we explain their usefulness in the expression of the pathophysiology of these lesions and their scintigraphic patterns. The article will also describe biomechanical and physiopathological aspects, injury mechanisms and clinical presentations of bone and joint sports injuries, knowledge of this is essential for the correct diagnostic assessment of imaging studies.

Complications of shoulder arthroplasty: added value of SPECT/CT imaging. / Complicaciones de las prótesis de hombro: valor añadido de la imagen SPECT/TC.

The incidence of prosthetic shoulder replacements has increased considerably in recent years, as well as the complications derived from the procedure. The correct diagnosis of each type of complication is essential for therapeutic decision making, which is currently based on the information provided by radiological and nuclear medicine imaging. Nevertheless, both techniques have intrinsic limitations that could be mostly overcome with the advent of the hybrid SPECT/CT imaging, which is set to play a fundamental role in the evaluation of shoulder prostheses.

The clinical contribution of SPECT/CT with 99mTc-HMPAO-labeled leukocyte scintigraphy in hip and knee prosthetic infections. / Aportación clínica de la SPECT/TC en la gammagrafía con leucocitos marcados con 99mTc-HMPAO en infección de prótesis de cadera y rodilla.

OBJECTIVES: White blood cell scanning with 99mTc-hexamethylpropylene amine oxime (HMPAO) has proven a sensitive and specific imaging method in the diagnosis of suspected prosthesis infection. The aim of this retrospective study was to evaluate the usefulness of SPECT/CT performed simultaneously using a hybrid imaging device of prosthesis infections. MATERIALS AND METHODS: 99mTc-HMPAO scintigraphy was performed on 37 patients (11 men and 26 women; age range 38-84 years; mean age±SD, 65.7±5.6 years). Planar scans were acquired 2.4 and 24hour after injection. SPECT/CT was obtained 4 h after injection, using a dual-head hybrid gama camera coupled with a low-power x-ray tube. In all patients, scintigraphic results were matched with the results of surgery, cultures and clinical follow-up. RESULTS: Seventeen (45,9%) out of 37 patients had prosthesis infection and 20 (54,1%) out of 37 patients had non-infectious prosthesis pathologies with 99mTc-HMPAO scintigraphy and SPECT/CT. The 99mTc-HMPAO scintigraphy was true-positive for infection in 16 of 37 patients and true-negative in 20 of 37 patients. SPECT/CT provided an accurate anatomic localization of all positive foci. With regard to the final diagnosis, SPECT/CT added a significant clinical contribution in 22 of 37 patients (59,4%). Sensitivity, specificity, negative predictive value and positive predictive values were 100%,59.1%,100%,62.5% in planar images with 99mTc-HMPAO scintigraphy and 100%,90.1%,100%,88.2% in the planar+SPECT/CT imaging, respectively. DISCUSSION: Our results indicate that SPECT/CT performed using a hybrid device can improve imaging with 99mTc-HMPAO scintigraphy in patients with suspected osteomyelitis by providing accurate anatomic localization and precise definition of the extent of infection.

Osificación heterotópica tras artroplastia de cadera: papel de la gammagrafía SPECT/TC ósea / Heterotopic ossification after hip arthroplasty: role of bone SPECT/CT scintigraphy

La osificación heterotópica es una condición limitante, que afecta predominantemente a la cadera. Dada su relación con patología postraumática/posquirúrgica, la gammagrafía ósea SPECT/TC resulta de especial utilidad en el diagnóstico diferencial con movilización protésica, aun cuando no hay alteraciones radiológicas. Además, resulta ser una herramienta eficaz para planificación quirúrgica atendiendo al grado de maduración ósea y la posibilidad de fabricar biomodelos mediante impresión 3D.(AU)

Heterotopic ossification is a limiting condition that predominantly affects the hip. Because of its association with post-trau-matic/postoperative pathology, bone SPECT/CT scintigraphy has proven to be especially useful regarding differential diag-nosis involving prosthetic mobilization, even in the absence of radiological abnormalities. Additionally, it is an effective toolfor surgical planning, considering the degree of bone maturation and the possibility of creating biomodels using 3Dprinting.(AU)

Different uptake of 123I-MIBG in the two main liver lobes: A persistant unsolved mistery. / Diferente captación de 123I-MIBG en los 2 lóbulos hepáticos principales: un misterio persistente sin resolver.

PURPOSE: After radiopharmaceutical injection, a heightened 123I-MIBG concentration is frequently observed in the left hepatic lobe compared to the right one, but the reason of this finding remains unknown. Our aim was to retrospectively analyze the different 123I-MIBG uptake pattern between the two hepatic lobes and correlate our results with some epidemiological/clinical features. MATERIAL AND METHODS: Ninety-four 123I-MIBG scintigraphies from 71 patients were selected. Regions of interest were drawn in the right and left lobes using transverse tomographic sections and left to right activity ratios (L/R ratio) were calculated at 6 and 24h after radiotracer administration. RESULTS: Twenty-seven examinations were positive for hypermetabolic lesions while the remaining 67 were negative. In all cases mean early and delayed L/R ratios were greater than 1.00; average early L/R ratio was 1.37 and delayed L/R ratio 1.52. The delayed L/R ratio was significantly higher than the early one. There was no difference in the L/R ratios with regard to age, gender, primary disease and result of scintigraphy. CONCLUSIONS: 123I-MIBG uptake was higher in left hepatic lobe compared to right and this ratio did not correlate with any epidemiological or clinical feature. The reason of this metabolic is not yet explained and some biomolecular hypotheses could be tested in 3D dynamic in vitro models.

A rare case of a 123I-MIBG SPECT/CT positive, but 68Ga-DOTA-TOC PET/CT negative pheochromocytoma of the bladder. / Caso infrecuente de feocromocitoma vesical positivo en la SPECT/TC con 123I-MIBG, pero negativo en la PET/TC con 68Ga-DOTA-TOC.

Pheochromocytoma (PHEO) is rare and belongs to the group of neuroendocrine tumours (NETs). These tumours can be found anywhere from the neck to the pelvis associated with sympathetic ganglia. Morphological imaging, for example CT, provides excellent anatomical detail and high sensitivity but lacks specificity as difficulties may occur when distinguishing between tumours derived from the sympathetic nervous system and other tumour entities. In contrast to anatomical imaging, functional imaging (123I-MIBG, 68Ga-DOTA-TOC PET) provides high sensitivity and specificity in detecting NETs. Early detection of PHEO is crucial and has a major effect on treatment and prognosis. This case report describes the important role of anatomical and functional imaging in a patient with a neuroendocrine tumour of unusual origin.

Hybrid imaging in foot and ankle disorders. / Imagen híbrida en la patología del pie y tobillo.

Disorders of the foot and ankle are some of the most frequent ones affecting the musculoskeletal system and have a great impact on patients' quality of life. Accurate diagnosis is an important clinical challenge because of the complex anatomy and function of the foot, that make it difficult to locate the source of the pain by routine clinical examination. In the study of foot pathology, anatomical imaging (radiography, magnetic resonance imaging [MRI], ultrasound and computed tomography [CT]) and functional imaging (bone scan, positron emission tomography [PET] and MRI) techniques have been used. Hybrid imaging combines the advantages of morphological and functional studies in a synergistic way, helping the clinician manage complex problems. In this article we delve into the anatomy and biomechanics of the foot and ankle and describe the potential indications for the current hybrid techniques available for the study of foot and ankle disease.

Fibroelastic pseudotumor elastofibroma dorsi detected by 18F-FDG PET/CT scan and by postherapy radioiodine SPECT/CT. / Seudotumor fibroelástico elastofibroma dorsi detectado por 18F-FDG PET/TC y por 131I SPECT/TC posterapia.

Radioiodine uptake in the thyroid tissue, metastasis of differentiated thyroid cancer (DTC), and in other tissues, depends on the expression of sodium-iodide symporter (NIS). Vascular permeability, effusions, inflammation, and other mechanisms may also play a role in the accumulation of radioactive iodine. A 63-year-old woman underwent radioiodine therapy, as well as a post-therapy whole-body scan, as she was suspected of having lung metastasis from thyroid carcinoma. The scan not only showed uptake at the lung metastasis but also a faint diffuse bilateral uptake in the posterior thorax. On SPECT/CT this uptake was located in a known Elastofibroma Dorsi (ED) previously diagnosed by contrast CT and viewed in a FDG PET/CT. The radioiodine uptake in ED, especially if typical, is not a diagnostic problem in SPECT/CT study, but can be misleading in a study limited to a few planar images, particularly if the uptake occurs asymmetrically, or ED is located in a unsuspected area.

67-Gallium SPECT/CT in febrile syndromes of unknown origin. / SPECT/TC con galio-67 en los síndromes febriles sin foco conocido.

INTRODUCTION AND OBJECTIVE: Febrile syndromes of unknown origin (FSUO) are complex processes in hospital practice. Their management includes an exhaustive medical history and examination, as well as an extensive number of biochemical tests. If these are inconclusive, diagnostic imaging techniques such as SPECT/CT with 67-Gallium Citrate (67Ga-SPECT/CT) could play an important role. We evaluated its role in the management of FSUO in our healthcare area. MATERIAL AND METHODS: We reviewed 57 patients who underwent a 67Ga-SPECT/CT due to a FSUO (32 women and 25 men, age range: 32-83 years old) obtaining scintigraphic findings, previous treatments and final diagnosis. Values of sensitivity, specificity, positive predictive values (VPP) and negative values (NPV) were obtained and compared with the results for PET/CT with 18Fluor-deoxy-glucose (18F-FDG PET/CT) found in the literature. RESULTS: The diagnoses found were: infection in 27/57 (47%), inflammatory disease in 15/57 (26%), neoplasm in 1/57 (1.75%) and patients without final diagnosis in 14/57 (24%). The statistical values of 67Ga-SPECT/CT were: sensitivity, specificity, PPV and NPV of 67%, 93%, 97% y 48%, respectively which were slightly lower than those found for the 18F-FDG PET/CT (86%, 52%, 70% and 92%, respectively). The diagnostic yield was 73% which increased to 80% in the patients who lacked empirical treatment. CONCLUSION: Despite the better results of 18F-FDG PET/CT, 67Ga-SPECT/CT behaved as a useful technique in the management of FSUO. It is advisable to use it if 18F-FDG PET/CT is not available.

Pancreatic accessory spleen. False positive with 99mTc-Octreotide.

The case is presented on a patient with abdominal pain and suspicion of neuroendocrine tumor in the tail of the pancreas shown in the abdominal CT and MRI. Whole-body scintigraphy and abdominal SPECT/CT with 99mTc-octreotide were performed that showed a nodular lesion partially on the posterior side of the pancreas tail. This nodule showed faint tracer uptake, and was reported as probable neuroendocrine tumor. Partial pancreatectomy and splenectomy were performed, and the histological study identified the lesion as an ectopic spleen. There are similar cases in the literature that match these findings, but this lesion is still frequently diagnosed after performing unnecessary surgery. When an asymptomatic intrapancreatic mass is detected, an accessory spleen should be considered and specific diagnostic techniques should be performed, such as labeled and denatured red blood cell SPECT/CT.