Gaba and serotonin molecular neuroimaging in essential tremor: a clinical correlation study.

BACKGROUND: Essential tremor is the most common movement disorder in adults, but its exact etiology and pathophysiology are still not fully understood. There is some consensus, however, about the involvement of the cerebellum and accumulating evidence points towards a dysfunction of the gabaergic system. We hypothesize that the serotonin neurotransmission system may also play a role as it does in tremor in Parkinson disease. This study aimed to investigate the association between the severity of tremor symptoms and the gabaergic and serotoninergic neurotransmission systems in essential tremor. MATERIAL AND METHODS: We measured the tremor clinical rating scale score and acquired DASB and Flumazenil PET scans in 10 patients who presented with essential tremor at different stages of clinical severity. Statistically significant correlations were sought between the scale scores and parametric binding potential images. RESULTS: The correlation analysis of cerebellar Flumazenil uptake and tremor clinical rating scale scores reached statistical significance (R2 = 0.423, p = 0.041), whereas no association was detected in the DASB scans. CONCLUSIONS: The severity of tremor correlated with the abnormalities found in GABA receptor binding, suggesting a primary gabaergic deficiency or a functional abnormality at the level of GABA(A) receptor subtypes. These results may assist in the rational development of new pharmacological treatments for essential tremor.

Comparison of positron emission tomography (PET) and computed tomography (CT) for better target volume definition in radiation therapy planning

BACKGROUND: In cancer patients, positron emission tomography/ computed tomography (PET/CT) fused images present less variability in target contouring, respect to use only CT images, respectively. However, the gold standard has not yet been clearly established between radiation oncologists with regard to PET images and the methodology of contouring targets with confidence using PET/CT fused images. The aim of this study was to determine whether integrated PET/CT fused images provide advantages in virtual simulation compared with morphological contouring only with CT. MATERIAL AND METHODS: Thirty cancer patients were evaluated in an adapted PET/CT hybrid in radiotherapy (RT) setup position, with 20 of them being suitable for RT: 17 were suitable for curative intent, which was the group of interest in this study. All image series were sent to the RT work station (WS) where CT and PET series were automatically fused by Digital Imaging and Communications in Medicine (DICOM) in each case. PET series were threshold and were subjected to source-to-background contrast algorithms to fi nally redefine the original tumour description. Three different radiotherapy plans (RTP) for each patient were compared after targets were contoured: [1] planning over metabolic (PET) contoured targets, [2] planning over only morphologic (CT) targets, and [3] planning over targets obtained for treatment based on fused PET/CT images. RESULTS: PET/CT findings altered initial-stage planning in four patients (23.5%) because they had been undergoing chemotherapy. Gross target volume (GTV) and planning target volume (PTV) based only on PET showed more homogeneity to obtain mean doses (p = 0.025) with respect to those based on PET/CT, respectively. However, no percentage differences were observed in median PTV doses between the planning methods, although there was higher variability in PET/CT planning. Morphological (CT) and PET/ CT target volumes were more voluminous than metabolic (PET) volumes. On the other hand, 20% of metabolic (PET) PTV were out of those defined by PET/CT. Thoracic RT plans based on PET preserved better bilateral lung [percentage volume of lung irradiated with a dose of 20 Gy (V20); significance, R(2) = 0.559, p = 0.006]. CONCLUSIONS: For our physicians, PET/CT fused images allowed better contouring of primary tumours in 40% of head and neck cancers and 34% of thoracic cancers. PET/CT provides useful information for virtual simulation therapy. Image treatment and planning in an RT workstation is mandatory (AU)

PET en neurología y psiquiatría II / PET in neurology and psychiatry II

No disponible

[Role of the positron emission tomography (PET) in suspected tumor recurrence when there is increased serum tumor markers]. / Papel de la tomografía por emisión de positrones (PET) en la sospecha de recidiva tumoral ante la elevación sérica de marcadores tumorales.

PURPOSE: Evaluate the usefulness of Positron Emission Tomography with 18F-Fluorodeoxyglucose (FDG-PET) to detect lesions when tumor recurrences are suspected due to the progressive increase of tumor markers and the study of their extension with negative or non-conclusive morphostructural diagnostic techniques. MATERIAL AND METHODS: Whole body FDG-PET was per-formed in 72 patients with different cancer diseases, 23 of whom had breast, 18 colorectal, 15 thyroid, 6 lung, 3 ovarian cancer and 7 had other types of cancers. Tumoral recurrence was suspected in all of the cases due to the progressive marker increase and negative or non-conclusive conventional studies. RESULTS: FDG-PET detected lesions in 85% patients, 33% of which were confirmed by the end of the study. In 40% of all cases, therapeutics measures were applied, 14% of which consisted in surgery with intention to cure. Sensitivity, specificity and accuracy were 96.4%, 75.6% and 93.9% respectively. CONCLUSIONS: Whole body FDG-PET is an accurate procedure in diagnosis of recurrent tumoral disease in patients with rising tumoral marker levels and with negative conventional morphostructural extension studies, and can make it possible to change the therapeutic approach in some cases.

6. 18F-FDG Whole Body Positron Emission Tomography (PET) in the Detection of Unknown Primary Tumors.

Purpose: To evaluate the utility of FDG-PET in detecting primary tumors in patients with metastatic disease from unknown primary tumors.Methods: 12 patients with metastases from unknown origin after unsuccessful conventional diagnostic procedures were studied. 5 had lymph node metastases (2 axillary, 2 cervical, 1 mediastinal), 3 multiple metastases, 1 in the lung, 1 in the cava vein, 1 in the brain and 1 in adrenal glands. Patients received 400MBq FDG intravenously, and whole body images were acquired 60 min. after injection with an ECAT EXACT HR+. PET results were compared with histological and clinical findings.Results: All but one metastatic lesion was identified by PET. Additional metastases were visualized in 4 patients. In one helped to guide biopsy for histological diagnosis. In 4/11 patients FDG-PET did not reveal lesions suspected to be primary tumor. FDG-PET identified primary tumor in 8/11 patients (breast: 2, pancreas: 2, base of tongue: 1, adrenal gland: 1, lung: 1, stomach: 1). In 4 of them (33% of total) primary tumor was confirmed either histologically or by the clinical evolution (breast: 2, lung: 1, pancreas: 1). In 1 patient FDG-PET was false positive (base of tongue). 3 patients positive FDG-PET have not yet been confirmed. FDG-PET influenced therapeutic procedures in 4 patients (33% of total). 2 underwent surgery (breast), 1 received specific chemotherapy (lung) and 1 palliative chemotherapy (pancreas).Conclusions: Our preliminary results suggest that FDG-PET is a non-invasive technique useful in the detection of unknown primary tumors, can influence in selecting appropriate therapeutic management and could guide biopsies for histologic analysis.

[Scintigraphy diagnosis of renovascular hypertension in renal transplanted patients]. / Diagnóstico gammagráfico de hipertensión renovascular en trasplantados renales.

UNLABELLED: Captopril renography (CR) has been shown to be a useful technique in the diagnosis of renovascular hypertension (RVH). This disease is a significant complication of the kidney transplanted patient so that early diagnosis would be extremely useful to preserve renal function and prevent graft loss. This work evaluates the role of CR, together with arteriography and doppler-ultrasound, in the diagnosis of RVH. MATERIALS: A total of 19 transplanted patients with clinical suspicion of RVH underwent an isotopic study, a doppler-ultrasound study and an arteriography. Scintigraphy was performed 1 hour after a 50 mg dose of captopril, with oral hydration and i.v. administration of approximately 111 MBq of 99mTc-MAG3 and 20 mg of furosemide. If abnormal, a subsequent renography in baseline conditions was performed for comparison. RESULTS: Overall, 11 patients had renovascular hypertension. Sensitivity and specificity of CR were 91% and 80% respectively, 100% and 60% for US and 91% and 100% for arteriography. The CR yielded one false positive result and 2 false negatives cases: one with 50% stenosis and one polar artery stenosis. Six patients were successfully dilated or operated. CONCLUSION: CR seems to be a reliable diagnostic tool for the diagnosis of renovascular hypertension in kidney transplanted patients.

Technetium-99m tetrofosmin scintigraphy to evaluate breast lesions.

UNLABELLED: The aim of this study is to characterise benign from malignant breast lesions by using 99mTc-Tetrofosmin. MATERIALS: Fifteen female patients with suspected breast lesions and ten normal controls underwent breast scintigraphy with 99mTc-Tetrofosmin. All patients had conventional mammography. Breast imaging begun 20 minutes after i.v. injection of 740 MBq 99mTc-Tetrofosmin. Patients were imaged in supine and prone position. Results of the 15 patients with suspected breast lesions, 13 showed breast uptake, and 6 of them had suspicious lesions on mammography. Surgery confirmed 10 carcinomas and 3 benign lesions. Two patients demonstrated no abnormal accumulation or suspicious findings in mammography. None of the normal controls had breast uptake or mammographic abnormalities. Our study has a sensibility of 100% and 60%, and a specificity of 80% and 100% in scintigraphy and mammography respectively. CONCLUSION: Our findings suggest that 99m Tc-Tetrofosmin may play a role in evaluating breast masses and that can differentiate benign from malignant lesions.