Revista Espa?ola de Medicina Nuclear (English Edition)最新文献

Elastofibroma dorsi has been described in the literature as an unusual tumor or pseudotumor. However, autopsies and imaging studies have revealed that it is a non-negligible finding.

Purpose

The aim of this study has been to illustrate and become familiar with this type of lesion in order to prevent misdiagnosis.

Materials and methods

From 3 December 2008 to 5 January 2010, 1,751 patients were evaluated with ¹⁸FDG-PET/CT. Of these, 29 cases of elastofibroma dorsi were recorded as an incidental finding. A retrospective and descriptive analysis was performed on this study series.

Results

The study showed a prevalence of 1.66%. Out of the 29 findings, 22 (75.86%) were females and 7 (24.14%) males. Seventeen (58.62%) cases were bilateral, 12 (41.38%) unilateral and the SUVmax ranged from 1.4 to 3.2. These lesions were reported as soft tissue density images with mild or moderate diffuse metabolic activity.

Conclusion

The elastofibroma dorsi is a relatively common finding in PET/CT that should be known in order to avoid making wrong diagnoses.

Objectives

The heart is one of the organs affected by sickle cell anemia (SCA). This prospective study has aimed to evaluate myocardial perfusion and left ventricle (LV) function in children with SCA by gated myocardial perfusion scintigraphy (G-MPS) and to compare the results with echocardiographic parameters.

Methods

Forty-three patients with SCA were evaluated by G-MPS and echocardiography. Myocardial perfusion and motion with thickening function were analyzed both visually and quantitatively. End-diastolic (EDV), end-systolic volumes (ESV), ejection fraction (EF), lung-to-heart (L/H) ratio were also calculated.

Results

None of the patients showed stress perfusion impairment in G-MPS. LV dilatation in 15 patients was observed both by G-MPS and echocardiography. EF values were within normal limits. Correlation between EF values calculated by two methods was not statistically significant. However, LV dilatation detected by both methods and EDV-ESV values in G-MPS were correlated to end-diastolic and end-systolic diameters calculated in echocardiography (p<0.05). M-Mode echocardiography revealed higher myocardial performance index (LV-MPI) in patients with LV dilatation. There was also a significant relationship between LV dilatation and frequent blood transfusions (>5/years) and acute chest syndrome (p<0.05).

Conclusion

Myocardial perfusion impairment in children with SCA is not frequently observed. Thus, performing the scintigraphy only in patients with cardiac symptoms should be considered. Since EF values of the children with SCA are not deteriorated in early stages, LV-MPI and LV dilatation should be considered as a significant parameter other than EF or perfusion data.

Epithelioid trophoblastic tumor is a recently described, rare and distinctive type of gestational trophoblastic tumor. We report the case of a 31-year old patient who had a full-term pregnancy 18 months before presentation. She had a right axillary lymph node metastasis and was referred for FDG-PET/CT scan for evaluation of distant metastasis and to detect primary malignancy. The axillary lymph node biopsy revealed metastatic breast carcinoma. FDG-PET/CT revealed increased uptake of right axillary lymph node, soft tissue density lesion with a diameter of 24 mm on left cervical region with increased FDG uptake, increased uptake on cervical region and left inguinal lymph node with increased uptake. Pelvic MRI imaging and ultrasonography were negative for malignancy in cervical region. Biopsy of the lesion was consistent with epithelioid trophoblastic tumor in cervical region. Gestational trophoblastic tumor was not suspected because she had no signs such as abnormal vaginal bleeding. FDG-PET/CT demonstrated the primary lesion in cervical region. We report a rare case of primary epithelioid trophoblastic tumor detected only with FDG-PET/CT scan which synchronized with breast carcinoma.

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 ^99mTc-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 ^99mTc 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.

Malignant pleural mesothelioma is a relatively rare, but highly aggressive, tumor, associated to exposure to asbestos, with a life expectancy between 9 and 17 months. Chest pain and dyspnea are the most frequent symptoms. The most commonly used therapy is surgery accompanied by chemotherapy. Preoperative assessment, after chemotherapy, has been done using magnetic resonance imaging and computed tomography (CT). However, these techniques cannot predict early response to therapy, because of the slow structural change of the tumor. The aim of this case report is to review and learn about the growing use of PET-CT imaging with ¹⁸F-FDG in the preoperative staging of malignant pleural mesothelioma and its influence in selecting the most appropriate type of surgery.

Background

Gallbladder carcinoma is a neoplasm having a poor prognosis in which the role of positron emission tomography with ¹⁸F-fluordeoxyglucose as a diagnostic tool, although of possible usefulness, has not been well-defined.

Methods/design

It is a prospective cohort of patients with radiologically malignant suspicious gallbladder lesions. A staging diagnostic presurgical FDG-PET study was carried out in each patient using both dedicated PET and multimodality PET-CT scanners. Diagnostic accuracy parameters were calculated from the results of PET imaging and were correlated with the condition and/or the clinical course of the patients. The clinical impact of its implementation in the diagnosis of gallbladder carcinoma was also analyzed.

Results

A total of 42 patients were recruited (22 malignant lesions, 20 benign). Overall diagnostic accuracy was 83.33% for the diagnosis of the primary lesion, 88.89% for the evaluation of lymph node involvement and 85.1% for the evaluation of metastatic disease. Mean SUVmax in malignant gallbladder lesions was 6.14 ± 2.89. ROC curve showed a cut-off value of 3.65 in the SUVmax for malignancy. Accuracy of PET studies alone (n = 21) was slightly lower than that of the PET/CT (n = 21). FDG-PET changed the management of 14.8% of the population due to the identification of unsuspected metastatic disease.

Comments

FDG-PET accurately diagnoses malignancy or benignity of suspicious gallbladder lesions, with the addition of its capacity to identify unsuspected metastatic disease. PET-CT improves the diagnostic accuracy of the procedure, due to the metabolic-structural complementarity of their information. The SUVmax has a complementary value added to the visual analysis.

Objective

To know the effective doses (E) that can be given in the common multimodal procedures in nuclear medicine, single photon emission tomography and positron emission tomography, combined with computed tomography, SPECT/CT and PET/CT. Effective dose will be expressed according to background equivalent radiation time (BERT) and the contribution of the CT scan to the total dose will also be studied.

Material and methods

The effective dose of each procedure has been calculated as the sum of the external radiation dose (CT part) and the internal one (radiopharmaceutical administration). Data from each side were collected through extensive literature search.

Results

A range of minimum and maximum effective doses [E_min, E_max] associated with each procedure is shown. These doses range from 0.5 to 49.1 mSv. BERT ranges from 2.6 months to 20.4 years. The CT contribution to the total effective dose varies from 2.1% to 93%, according to the image acquisition protocol and its purpose. Performing a diagnostic CT scan increases the dose up to a factor of 4.3 times compared to the dose used for CT acquisition for attenuation correction and anatomic localization.

Conclusions

This article focuses on the effective dose level that can be given in multimodal procedures, bearing in mind that the data are subject to constant changes and should be updated periodically. It is important to know the dosimetric impact when the CT scan is added. The application of optimized protocols according to the indication of the study reduces patient's exposure without loss of significant information.