[Impact of positron emission tomography with FDG-PET in treatment of patients with suspected recurrent ovarian cancer]. / Impacto de la tomografía por emisión de positrones mediante 18-Fluoro-2-Desoxi-D-Glucosa (PET-FDG) en el manejo terapéutico de pacientes con recurrencia secundaria a cáncer de ovario.

AIM: Recurrent ovarian cancer is a major problem and an accurate diagnosis can often change patients' management. This study aimed to assess the impact on management of FDG-PET in recurrent ovarian cancer. MATERIAL AND METHODS: Forty-three patients in whom FDG-PET scan was performed due to suspected recurrent ovarian cancer were included. FDG-PET results were confirmed by histopathology and clinical follow-up of at least 12 months. To assess impact on management the treatment plan based on conventional imaging methods was compared with the treatment plan based on inclusion of PET findings, classifying FDG-PET impact on management as high, medium, low or no impact. Management changes, when present, were classified as intermodality or intramodality. RESULTS: FDG-PET had a high impact on therapeutic management in 28 patients (65.1 %), medium impact in 2 patients (4.6 %), low impact in 9 patients (20.9 %), and no impact in 4 patients (9.3 %). FDG-PET induced an intermodality change in management in 27 patients (62,8 %); intramodality changes were induced in 3 patients (7 %). Finally, it produced no treatment changes in 13 patients (30.2 %). CONCLUSION: FDG-PET supplied additional information when compared to conventional diagnostic procedures and allowed adequate management changes in most patients.

Thallium scintigraphy in human transplants: a way to detect myocardial damage.

An original index has been derived from thallium images to detect histopathologic changes in heart transplant patients. One hundred eighty-four static and end-diastolic images with thallium were recorded 5 minutes after injection in the left anterior oblique projection. Twenty patients and 14 healthy volunteers were studied. The epicardial and endocardial borders were determined, and the difference of these values was considered the myocardial area. The results in heart transplants were compared with the results of endomyocardial biopsies (N = 142). A significant decrease (p less than 0.01) was found in the index of the myocardial area between normal biopsy results and mild and moderate rejection. Differences were not detected between studies performed in several postoperative periods in the absence of rejection. The results in healthy volunteers prove that the index does not change between studies performed at different times in the same subject, although the value obtained from the end-diastolic image was more constant. On the basis of these results, it is possible to suggest that the decrease in the myocardial area during rejection is the result of a fall of thallium uptake by the myocardium. Capillary endothelial hyperplasia, perivascular infiltration, and myocytolysis can justify these changes, although the presence of other histologic findings, such as intramyocardial edema, could influence the value of this index. We conclude that the uptake of thallium decreases during acute rejection episodes; the results obtained from the images, in this work, are an expression of this event.

Respiratory distress syndrome. A suggestive pattern of shunt effect detected by means of macroparticles.

An esophagobronchial fistula developed in a patient who had well-differentiated squamous carcinoma of the lung that was treated with chemotherapy. Because the esophagobronchial fistula could not be surgically repaired, it was isolated with a mechanical stitch above and below it. Forty-eight hours after initiation of enteral nutrition, a perfusion lung scan was performed because of clinical suspicion of pulmonary embolism. Because the scan showed reduced pulmonary radioactivity and accumulation of activity in the kidneys and spine, an arteriovenous shunt was suspected. However, subsequent digital subtraction angiography ruled out this possibility and a recurrence of the esophagobronchial fistula was confirmed with an esophagogram. The unusual extrapulmonary activity could be related to a reversible capillary shunt in the pulmonary vasculature, secondary to acute respiratory distress syndrome.

Patient surface radiation doses at two PET imaging facilities.

To develop a practical means of auditing the procedures and to optimize the administered radionuclide activity, patient surface radiation doses following the administration of 18FDG for PET imaging have been measured at breast and gonad locations at two PET facilities. Patient dosimetry was performed using LiF TLD-100 chips placed near the breasts and gonads for 2 h following tracer injection. Standard uptake values from the image-reconstruction algorithms of one PET camera were investigated in regions of interest in tomograms of the myocardium and liver with the aim of validating dosimetry at breasts. Mean doses measured on the patient's skin ranged between 3.3 and 6.1 microGy MBq(-1) at the gonads and between 3.9 and 6.4 microGy MBq(-1) at the breasts, noticeably lower than the calculations reported in the literature. These values show good concordance with the injected activities, although they are not proportional. The proportion of injected activity actually contributing to image production seems to decrease gradually as the injected activity increases. Conversely, for a given injected activity, breast and gonadal doses were found to be lower than the values expected from the numerical calculations reported in the literature, showing increasing discrepancies when the injected activity increased. Doses measured at the right breast were consistently higher than for the left, which is indicative of greater radiotracer absorption by the liver compared to the average absorption in the body.

[Brain photon emission tomography. Value of the corticocerebellar index and gammagraphic patterns in Alzheimer's disease and other diseases]. / Tomografía de emisión de fotones cerebral. Valor del índice corticocerebeloso y patrones gammagráficos en la enfermedad de Alzheimer y otras afecciones.

Brain single photon emission computed tomography (SPECT) with 99mTc-HMPAO is a diagnostic tool for evaluating regional cerebral blood flow. Recently, the diagnostic possibilities of the method are being investigated in some neurologic disorders, such as cerebrovascular accidents, seizures and dementia. This work has been carried out with 54 subjects, 9 healthy volunteers and 45 patients (31 dementia and 14 epileptics), in order to evaluate gammagraphic patterns and the utility of cortico/cerebellar activity indexes. An interesting diagnostic finding is a significant decrease (p less than 0.001) in perfusion of temporoparietal regions in the patients with Alzheimer's disease in relation with the healthy volunteers' group. We have not found significant changes in perfusion in the group of epileptic patients during the interictal phase. We conclude emphasizing the interest of the SPECT in the differential diagnosis of dementia.

[Photon-emission tomography (SPECT) in the detection of hepatic hemangiomas of small size]. / Contribución de la tomografía de emisión de fotones (SPECT) en la detección de hemangiomas hepáticos de pequeño tamaño.

By means of ultrasonography it is possible to detect hepatic lesions of few millimeters, however, it doesn't give a precise diagnosis. The role of planar scintigraphy in the diagnosis of hepatic hemangioma has already been established, although it has limitations which are partially solved by means of SPECT. 46 patients with different pathologies and 9 healthy volunteers have been studied. In the 19 confirmed hemangiomas, planar scintigraphy showed a sensitivity of 73.6% versus 84.2% for SPECT, mostly due to lesions less than 2.5 cm. Besides that, SPECT allowed a correct visualization of abdominal and intrahepatic major vessels, although lesions less than 1.5 cm are difficult to evaluate.

[Neuroimaging in epilepsy. Advances in SPECT and PET in epilepsy]. / Neuroimagen en epilepsia. Avances en SPECT y PET en epilepsia.

INTRODUCTION: The incorporation of neuroimaging techniques into the protocol for localization of epileptogenous foci has considerably reduced the need for use of intracranial electrodes. DEVELOPMENT: SPECT and PET are most useful in cases of epilepsy with no cerebral morphological anomalies, in which there are therefore no changes which shown on MR. Cerebral SPECT with perfused tracers, such as 99mTc-HMPAO, 123I-MP or 99mTc-ECD, permit the study of patients during interictal and perictal phases. In the latter case, although the procedure is complex, one may observe an increase in cerebral blood flow in the epileptogenous focus in 90% of the patients. PET with FDG allows interictal study of patients, and shows reduced metabolism in the epileptogenic region. By comparison with video-EEG there are S = 84% and SP = 86% in temporal lobe epilepsy. The diagnostic efficiency of these two techniques is rather less in the localization of extratemporal foci and in multifocal epilepsies, although it is always better than with other diagnostic techniques. They have also been shown to be useful in the prognosis of functional recovery after surgery. CONCLUSION: The possibility of studying neuroreceptors may be of great use in the investigation of the etiopathogenesis of epilepsy, and thus lead to improvement in the clinical and therapeutic management of patients. With SPECT, 123I-Iomacenil and 123I-lododexetimide are used. With PET and 11C-Carfentanyl opiate receptors have been studied. With 11C-Fluomacenil one may study the cerebral distribution of the benzodiazepine receptors.

[Diagnostic accuracy of semiquantitative analysis of positron emission tomography in radiologically indeterminate lung lesions]. / Exactitud diagnóstica del análisis semicuantitativo de la tomografía por emisión de positrones en lesiones pulmonares radiológicamente indeterminadas.

OBJECTIVE: The objective of this work was to assess the Standardized Uptake Value (SUV) in the differential diagnosis of radiologically indeterminate lung lesions by means of ROC curves. MATERIAL AND METHOD: Forty seven patients were studied by Positron Emission Tomography with 18-fluorine-2-desoxy-D-glucose (FDG PET) analyzing the value of maximum SUV. The patients were classified into three groups. Group 1 = patients without previous neoplasia (WPN) + patients with previous neoplasia (PN). Group 2 = WPN. Group 3 = PN. RESULTS: The ROC curves showed a high diagnostic accuracy in the three groups, with area under the curve (AUC) values of 0.96, 0.98 and 0.91 respectively. The typical error was 0.03, 0.02 and 0.08. The maximum SUV cutoffs with the best diagnostic accuracy for the three groups were: 2.6; 3 and 2.4, with an accuracy (A) of 93.6%, 97% and 92.3%, respectively. Analyzing all the patients globally (group 1), we obtained one false positive result in a patient with hamartoma (max SUV = 2.8) and two false negative results in one patient with lung metastases from malignant fibrohistiocytoma (max SUV = 0.7) and in another patient with lung metastases from unknown origin adenocarcinoma (max SUV = 1.9). CONCLUSIONS: FDG PET permits differentiation with a very high diagnostic accuracy of benign and malignant lung lesions using the maximum SUV. The differences observed between the different groups are due to the different disease prevalence, obtaining a lower negative predictive value of max SUV in patients with previous neoplasia.

201Tl myocardial perfusion in the management of the transplanted heart.

A semi quantitative method with thallium has been applied in the management of cardiac transplants. In all, 142 scans were performed in 20 patients and were arranged in 3 groups that represent respectively all controls performed to the transplants (G1), and a selection of the scans obtained during the 1st rejection episode in each patient (G2) and the 2nd if present (G3). A heart/lung index was calculated through early and late images (IA, IB), obtained 5 min and 4 h post injection of thallium. A decrease in IA was detected during acute rejection in all groups. This fall was statistically significant from the mild to moderate rejection degree in G1 (P less than 0.01), and the mild rejection in G3 (P less than 0.001). IB was not modified with rejection. Comparing the biopsies with and without edema, in the absence of rejection, it has been proved that the intra myocardial edema can produce a decrease in IA (P less than 0.001). We conclude that IA is a simple and sensitive index to evaluate the graft, although intra myocardial edema can reduce its specificity.