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.

[Complete hormonal and metabolic response after iodine-131 metaiodobenzylguanidine treatment in a patient diagnosed of malignant pheochromocytoma]. / Respuesta hormonal y metabólica completa tras el tratamiento con yodo-131 metayodobencilguanidina en un caso de feocromocitoma maligno.

Radiolabeled metaiodobenzylguanidine is an analogue of norepinephrine used to localize tumors that express the neurohormone transporters, specifically those derived from the neural crest having a neuroendocrine origin. It is also used to treat non-surgical metastases derived from them. A review of the literature revealed symptomatic improvements associated to a decrease in hormone levels in a significant percentage of patients after (131)I-MIBG treatment. However, complete tumor remission has been described only in very few cases and hardly ever when bone metastases exist. We present a case of a patient diagnosed of malignant pheochromocytoma who achieved complete hormonal and metabolic response after (131)I-MIBG treatment (600 mCi) in spite of the presence of bone metastases.

[Non-invasive diagnosis of posttraumatic thoracic splenosis]. / Diagnóstico no invasivo de la esplenosis torácica postraumática.

Intrathoracic splenosis is a generally asymptomatic entity incidentally diagnosed after the completion of an Rx, CT scan or MRI for another reason. The performance of scintigraphy with (99m)Tc-labelled heat-denatured erythrocytes allows the noninvasive diagnosis of this entity and avoids more aggressive diagnostic techniques such as FNAP or thoracotomy. Because this splenic tissue may be partially or fully functioning and therefore may have some beneficial immune function for the patient, the management of this entity should be conservative. Radioisotopic scintigraphy with (99m)Tc labelled heat-denatured erythrocytes is the technique with the greatest specificity in the demonstration of splenic tissue. The presence of subpleural pulmonary nodules, associated or not with intra-abdominal nodules, together with the existence of previous partial or total splenectomy, traumatic or not, with or without associated rupture of the diaphragm, should raise suspicion of the presence of intrathoracic splenosis.

[Iodine uptake in the chest in the follow-up of well-differentiated thyroid cancer]. / Captación torácica de (131)I en el seguimiento del cáncer diferenciado de tiroides.

Differentiated thyroid cancer is a disease having a very good prognosis when treated adequately. Ablation treatment with (131)I is frequently adjunct to surgery in these patients since it improves survival. Radioiodine whole-body scan is one of the imaging modality of choice in the follow-up of patients with this kind of pathology. After ablation treatment of the thyroid gland, any radioiodine accumulation in a non-physiological location usually means the presence of functioning metastasis. Recognition of potential false-positives is essential to avoid unnecessary exposure to further radiation from repeated therapeutic doses of radioactive iodine. We report a case of uptake in the chest due to bronchiectasis, potentially masquerading as pulmonary metastasis.

[Left distal femoral diaphysis-metaphyseal injury in a 13-year-old patient]. / Lesión diafiso-metafisaria distal femoral izquierda en paciente de 13 años.

This paper aims to present the usefulness of the different diagnosis imaging methods (anatomical and functional) in the characterization of bone injury. Any data, however insignificant, is justified and should be specified. In this case, the discrepancy between the vascular and pool phases in the bone scintigraphy with 99mTc-MDP reveals revealed a lesion with an intense reaction secondary to the "foreign body effect", which is not necessarily malignant.