Metabolic targeting can improve the efficiency of brain tumor biopsies.

Brain tumors comprise a heterogeneous group of diseases, featuring different biology, prognosis, and treatment. The most known forms are malignant gliomas and metastases. Brain biopsy is a recognized technique in the management of intracranial space-occupying lesions and tumors in particular. Tumor heterogeneity of malignant brain lesions has been described and can lead to significant sampling errors in stereotactic biopsy. Different methods have been used to perform biopsies, including biopsy guided by CT or RMI, echoguided or stereotactic. The choice of the target with the help of PET and MRI with spectroscopy allows one to identify metabolically more active areas of the tumor, and in this way reduce the rate of negative results.

Diverse Behavior in 18F-Fluorocholine PET/CT of Brain Tumors in Patients With Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder that causes CNS tumors in around 20% of patients, being pilocytic astrocytomas (PA), and particularly optic pathway gliomas (OPG), the most common. We present three cases of NF1 patients referred for F-fluorocholine PET/CT because of suspected glioma in the setting of ongoing FUMEGA (Functional and Metabolic Glioma Analysis) trial. One case turned out to be a WHO grade I ganglioglioma; the second was a high grade glioma; and the last one (negative in PET) a probable low-grade glioma.

18F-Fluorocholine PET/CT, Brain MRI, and 5-Aminolevulinic Acid for the Assessment of Tumor Resection in High-Grade Glioma.

High-grade glioma is a very aggressive and infiltrative tumor in which complete resection is a chance for a better outcome. We present the case of a 57-year-old man with a brain lesion suggestive of high-grade glioma. Brain MRI and F-fluorocholine PET/CT were performed previously to plan the surgery. Surgery was microscope assisted after the administration of 5-aminolevulinic acid. Postsurgery brain MRI and PET were blind evaluated to the surgery results and reported as probably gross total resection.

¹8F-FDG PET/contrast enhanced CT in the standard surveillance of high risk colorectal cancer patients.

OBJECTIVE: To assess the accuracy of FDG-PET/contrast enhanced CT (FDG-PET/ceCT) in the detection of unsuspected recurrence of colorectal cancer (CRC) in patients with high risk of relapse. METHODS: Thirty-three patients (14 females and 19 males, mean age: 62, range: 41-78), with CRC in complete remission, were prospectively included. All patients underwent FDG-PET/ceCT (58 studies). FDG-PET/ceCT was requested in the surveillance setting, and performed following a standardized protocol. A portal venous phase CT scan was performed after the injection of iodinated contrast agent. An individual and combined assessment of both techniques (PET and ceCT) was performed. Concordant and discordant findings of PET, ceCT and FDG-PET/ceCT were compared in a patient-based and a lesion-based analysis. The final diagnosis, recurrence or disease free status (DFS), were established by histopathology or clinical/radiological follow-up of at least 6 months. RESULTS: Seven out of 33 patients had a confirmed recurrence and the rest of patients had a DFS. In a patient-based analysis the sensitivity and specificity of PET, ceCT and PET/ceCT was of 86% and 88%, 86% and 92%, 86% and 85%, respectively. Attending to the lesion-based analysis, the sensitivity for PET, ceCT and PET/ceCT was of 56%, 71% and 97%, respectively. Both techniques showed a good concordance in the establishment of the final patient status. However, on a lesion-based analysis, no concordance was observed between them. CONCLUSION: PET and ceCT seem to have similar value in the detection of unsuspected recurrence of CRC in a patient-based analysis. However, the combined assessment of PET/ceCT improves the accuracy in the lesion-based analysis.

Role of color Doppler imaging in early diagnosis and prediction of progression in glaucoma.

This longitudinal and prospective study analyzes the ability of orbital blood flow measured by color Doppler imaging (CDI) to predict glaucoma progression in patients with glaucoma risk factors. Patients with normal perimetry but having glaucoma risk factors and patients in the initial phase of glaucoma were prospectively included in the study and divided, after a five-year follow-up, into two groups: "Progression" and "No Progression" based on the changes in the Moorfields regression analysis (MRA) classification of Heidelberg retina tomograph (HRT). An orbital CDI was performed in all patients and the parameters obtained were correlated with changes in HRT. A logistic discrimination function (LDF) was calculated for ophthalmic artery (OA) and central retinal artery (CRA) parameters. Receiver operating characteristics curves (ROC) were used to assess the usefulness of LDFs to predict glaucomatous progression. A total of 71 eyes were included. End-diastolic velocity, time-averaged velocity, and resistive index in the OA and CRA were significantly different (P < 0.05) between the Progression and No Progression groups. The area under the ROC curves calculated for both LDFs was of 0.695 (OA) and 0.624 (CRA). More studies are needed to evaluate the ability of CDI to perform early diagnosis and to predict progression in glaucoma in eyes.

Enfermedad de Madelung / Madelung’s disease

No disponible

Response assessment of colorectal liver metastases with contrast enhanced CT/18F-FDG PET.

PURPOSE: Evaluate the diagnostic performance of contrast enhanced CT/PET (ceCT/PET) in the response assessment of patients with colorectal cancer liver metastases. METHODS: 33 ce CT/PET studies of 19 patients with colorectal liver metastases were prospectively evaluated. All of them, 13 (68.4%) were males and 6 (31.6%) females. Mean age and range were 63 [42-78]. All patients were treated with neoadjuvant chemotherapy. In all cases post-therapy diagnostic confirmation of liver lesions was obtained. A ce CT PET/was obtained 1h after the injection of 370 MBq of 18F-FDG. Metabolic and morphologic studies were evaluated by two blinded nuclear physicians and radiologists respectively to assess the location, size and suspected diagnosis of lesions (benign or malignant). A combined assessment of both techniques was performed. The final diagnosis was established by histopathology or clinical/radiological follow-up greater than 6 months. RESULTS: A total of 120 liver lesions were identified, 115 were malignant and 5 benign. From the malignant lesions, 105 were identified with the ceCT, 44 with the PET and 109 with ceCT/PET. All of the benign lesions were correctly classified with any of the three imaging techniques. The sensitivity of PET, ceCT and ceCT/PET were of 38%, 91% and 95% respectively and the specificity was 100% in all three of the diagnostic studies. CONCLUSION: Administration of intravenous contrast in the PET/CT is mandatory to evaluate treatment response rate of liver metastases due to the limitations of isolated metabolic images in these cases.