Xavier Setoain

Clinical Role of Subtraction Ictal SPECT Coregistered to MR Imaging and (18)F-FDG PET in Pediatric Epilepsy.

A precise assessment of the drug-resistant epileptic pediatric population for surgical candidacy is often challenging, and to date there are no evidence-based guidelines for presurgical identification of the epileptogenic zone. To evaluate the usefulness of radionuclide imaging techniques for presurgical evaluation of epileptic pediatric patients, we compared the results of video-electroencephalography (EEG), brain MR imaging, interictal SPECT, ictal SPECT, subtraction ictal SPECT coregistered to MR imaging (SISCOM), and interictal PET with 18F-FDG. Methods: Fifty-four children with drug-resistant epilepsy who had undergone video-EEG monitoring, brain MR imaging, interictal and ictal brain perfusion SPECT, SISCOM, and 18F-FDG PET were included in this study. All abnormal findings revealed by these neuroimaging techniques were compared with the presumed location of the epileptogenic zone (PEZ) as determined by video-EEG and clinical data. The proportion of localizing studies for each technique was statistically compared. In the 18 patients who underwent resective brain surgery, neuroimaging results were compared with histopathology results and surgical outcome. Results: SISCOM and 18F-FDG PET concordance with the PEZ was significantly higher than MR imaging (P < 0.05). MR imaging showed localizing results in 21 of 54 cases (39%), SISCOM in 36 of 54 cases (67%), and 18F-FDG PET in 31 of 54 cases (57%). If we consider SISCOM and 18F-FDG PET results together, nuclear medicine imaging techniques showed coinciding video-EEG results in 76% of patients (41/54). In those cases in which MR imaging failed to identify any epileptogenic lesion (61% [33/54]), SISCOM or 18F-FDG PET findings matched PEZ in 67% (22/33) of cases. Conclusion: SISCOM and 18F-FDG PET provide complementary presurgical information that matched video-EEG results and clinical data in three fourths of our sample. SISCOM was particularly useful in those cases in which MR imaging findings were abnormal but no epileptogenic lesion was identified. Radionuclide imaging techniques are both useful and reliable, extending the possibility of surgical treatment to patients who may have been discouraged without a nuclear medicine approach.

Accuracy of arterial spin labeling magnetic resonance imaging (MRI) perfusion in detecting the epileptogenic zone in patients with drug‐resistant neocortical epilepsy: comparison with electrophysiological data, structural MRI, SISCOM and FDG‐PET

Locating the epileptogenic zone (EZ) in patients with neocortical epilepsy presents major challenges. Our aim was to assess the accuracy of arterial spin labeling (ASL), an emerging non‐invasive magnetic resonance imaging (MRI) perfusion technique, to locate the EZ in patients with drug‐resistant neocortical epilepsy.

Seizure‐onset zone localization by statistical parametric mapping in visually normal 18F‐FDG PET studies

Neuroimaging is crucial in the presurgical evaluation of patients with medically refractory epilepsy. To improve the moderate sensitivity of [18F]fluorodeoxyglucose–positron emission tomography (18F‐FDG‐PET), our aim was to evaluate the usefulness of statistical parametric mapping (SPM) to localize the seizure‐onset zone (SOZ) in PET studies deemed normal by visual assessment.

PET y SPECT en la epilepsia

Epilepsy is one of the most frequent chronic neurological disorders, affecting 1-2% of the population. Patients with complex partial drug resistant episodes may benefit from a surgical treatment consisting in the excision of the epileptogenic area. Localization of the epileptogenic area was classically performed with video-EEG and magnetic resonance (MR). Recently, functional neuroimaging studies of Nuclear Medicine, positron emission tomography (PET) and single photon emission tomography (SPECT) have demonstrated their utility in the localization of the epileptogenic area prior to surgery. Ictal SPECT with brain perfusion tracers show an increase in blood flow in the initial ictal focus, while PET with (18)FDG demonstrates a decrease of glucose metabolism in the interictal functional deficit zone. In this review, the basic principles and methodological characteristics of the SPECT and PET in epilepsy are described. The ictal SPECT injection mechanism, different patterns of perfusion based on the time of ictal, postictal or interictal injection are detailed and the different diagnostic sensitivities of each one of these SPECT are reviewed. Different methods of analysis of the images with substraction and fusion systems with the MR are described. Similarly, the injection methodology, quantification and evaluation of the images of the PET in epilepsy are described. Finally, the main clinical indications of SPECT and PET in temporal and extratemporal epilepsy are detailed.

18F-FDG PET/TC con imagen hepática en dos tiempos en la sospecha de recidiva del cáncer colorrectal

AIM To analyze the potential improvement of (18)F-fluorodeoxyglucose (FDG) PET/CT using additional delayed images of the liver in operated colorectal cancer. MATERIAL AND METHODS The study prospectively included 71 patients (22 women, 49 men) with mean age of 65 ± 11 years with clinical, analytic or radiological suspicion of current disease. A whole body PET/CT scan was performed at 60 min. (standard images) and after 2 hr (delayed images) post-injection of 4.07 MBq/Kg of (18)F-FDG. Visual and quantitative SUV analysis of PET/CT findings was done. All findings were confirmed by histopathology and/or at least 6 months follow-up. RESULTS Thirty-seven out of 71 patients were diagnosed of liver metastases (79 metastases). In 38/71 cases there was extra-hepatic disease in the form of local recurrence (10), abdominopelvic (3) or mediastinal (3) lymph nodes, bone (1) or lung metastases (16) and carcinomatosis (10). Sensitivity and specificity in the diagnosis of liver metastases in a patient-by-patient basis in standard (81% and 91%) and in delayed images (95% y 97%) was calculated. The number of lesions detected in delayed images was significantly higher (66/79) than in standard images (57/79). Sensitivity and specificity for PET/CT in the diagnosis of extra-hepatic disease was 84% and 70%, contributing to the detection of synchronous tumors in 5 patients. CONCLUSIONS PET/CT may be useful in the diagnosis of extra-hepatic disease in suspected recurrence of colorectal cancer. Delayed images on PET/CT may increase the sensitivity to identify liver metastases.

Absceso del psoas como causa de dolor lumbar detectado mediante gammagrafía con galio en un paciente con sospecha de espondilodiscitis

Resumen Varon de 56 anos con fiebre y dolor lumbar al que se realizo TC abdominal mostrando cambios artrosicos lumbares, aunque sin poder descartar patologia infecciosa en L5/S1. Se solicito gammagrafia osea que evidencio hipercaptacion heterogenea que no permitio excluir una espondilodiscitis en esta localizacion. La gammagrafia con 67Ga-citrato excluyo patologia infecciosa en columna lumbar. Sin embargo, visualizo una captacion patologica en fosa iliaca izquierda sugestiva de absceso del psoas, confirmada mediante ecografia aislandose estreptococo viridans.