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ABSTRACT: The purpose of this study was to evaluate whether single-voxel (1)H MRS could add useful information to conventional MRI in the preoperative characterisation of the type and grade of brain tumours. MRI and MRS examinations from a prospective cohort of 40 consecutive patients were analysed double blind by radiologists and spectroscopists before the histological diagnosis was known. The spectroscopists had only the MR spectra, whereas the radiologists had both the MR images and basic clinical details (age, sex and presenting symptoms). Then, the radiologists and spectroscopists exchanged their predictions and re-evaluated their initial opinions, taking into account the new evidence. Spectroscopists used four different systems of analysis for (1)H MRS data, and the efficacy of each of these methods was also evaluated. Information extracted from (1)H MRS significantly improved the radiologists' MRI-based characterisation of grade IV tumours (glioblastomas, metastases, medulloblastomas and lymphomas) in the cohort [area under the curve (AUC) in the MRI re-evaluation 0.93 versus AUC in the MRI evaluation 0.85], and also of the less malignant glial tumours (AUC in the MRI re-evaluation 0.93 versus AUC in the MRI evaluation 0.81). One of the MRS analysis systems used, the INTERPRET (International Network for Pattern Recognition of Tumours Using Magnetic Resonance) decision support system, outperformed the others, as well as being better than the MRI evaluation for the characterisation of grade III astrocytomas. Thus, preoperative MRS data improve the radiologists' performance in diagnosing grade IV tumours and, for those of grade II-III, MRS data help them to recognise the glial lineage. Even in cases in which their diagnoses were not improved, the provision of MRS data to the radiologists had no negative influence on their predictions.
NMR in Biomedicine 09/2011; 25(4):661-73. · 3.21 Impact Factor
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Acta Neurochirurgica 09/2011; 153(12):2457-9. · 1.52 Impact Factor
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ABSTRACT: To investigate the effect of temperature (0 versus 37 degrees C) in the high-resolution magic angle spinning spectroscopy (HRMAS) pattern of human brain tumor biopsies and its influence in recognition-based tumor type prediction. This proof-of-principle study addressed the bilateral discrimination between meningioma (MM) and glioblastoma multiforme (GBM) cases.
Forty-three tumor biopsy samples were collected (20 MM and 23 GBM), kept frozen and later analyzed at 0 degrees C and 37 degrees C by HRMAS. Post-HRMAS histopathology was used to validate the tumor type. Time-course experiments (100 min) at both temperatures were carried out to monitor HRMAS pattern changes. Principal component analysis and linear discriminant analysis were used for classifier development with a training set of 20 biopsies.
Temperature-dependent, spectral pattern changes mostly affected mobile lipids and choline-containing compounds resonances and were essentially reversible. Incubation of 3 MM and 3 GBM at 37 degrees C during 100 minutes produced irreversible pattern changes below 13% in a few resonances. Classification performance of an independent test set of 7 biopsies was 100% for the pulse-and-acquire, CPMG at echo times (TE) of 30 ms and 144 ms and Hahn Echo at TE 30 ms at 0 degrees C and 37 degrees C. The performance for Hahn Echo spectra at 136 ms was 83.3% at 0 degrees C and 100% at 37 degrees C.
The spectral pattern of mobile lipids changes reversibly with temperature. HRMAS demonstrated potential for automated brain tumor biopsy classification. No advantage was obtained when acquiring spectra at 37 degrees C with respect to 0 degrees C in most of the conditions used for the discrimination addressed.
MAGMA Magnetic Resonance Materials in Physics Biology and Medicine 09/2010; 23(4):203-15. · 1.88 Impact Factor
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ABSTRACT: Development of molecular diagnostics that can reliably differentiate amongst different subtypes of brain tumors is an important unmet clinical need in postgenomics medicine and clinical oncology. A simple linear formula derived from gene expression values of four genes (GFAP, PTPRZ1, GPM6B, and PRELP) measured from cDNA microarrays (n = 35) have distinguished glioblastoma and meningioma cases in a previous study. We herein extend this work further and report that the above predictor formula showed its robustness when applied to Affymetrix microarray data acquired prospectively in our laboratory (n = 80) as well as publicly available data (n = 98). Importantly, GFAP and GPM6B were both retained as being significant in the predictive model upon using the Affymetrix data obtained in our laboratory, whereas the other two predictor genes were SFRP2 and SLC6A2. These results collectively indicate the importance of the expression values of GFAP and GPM6B genes sampled from the two types of microarray technologies tested. The high prediction accuracy obtained in these instances demonstrates the robustness of the predictors across microarray platforms used. This result would require further validation with a larger population of meningioma and glioblastoma cases. At any rate, this study paves the way for further application of gene signatures to more stringent biopsy discrimination challenges.
Omics: a journal of integrative biology 03/2010; 14(2):157-64. · 2.29 Impact Factor
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ABSTRACT: The etiology of cavernous sinus syndrome (CSS) remains difficult to determine in spite of the development of neuroimaging techniques. We conducted the current study to identify clinical and imaging features that allow a reliable approach to the etiologic diagnosis of patients with CSS. We studied a consecutive series of 126 patients with CSS, defined as involvement of 2 or more of the third, fourth, fifth (V1, V2), or sixth cranial nerves, or involvement of only 1 of them in combination with a neuroimaging-confirmed lesion in the cavernous sinus. Tumors were the most common cause of CSS (80 patients). All patients with optic nerve involvement had a tumor. No patient with a normal MRI had a tumor. The lack of pain during the course of the disease (odds ratio [OR], 0.58; 95% confidence intervals [CI], 0.06-0.40), V2 involvement (OR, 12.17; 95% CI, 2.98-49.71), and male sex (OR, 3.2; 95% CI, 1.31-8.14) were independently associated with the presence of a tumor. Pain at the onset of disease (OR, 12.09; 95% CI, 3.14-46.50) and third cranial nerve involvement (OR, 4.9; 95% CI, 1.01-24.60) were independently associated with Tolosa-Hunt syndrome.
Medicine 10/2007; 86(5):278-81. · 4.35 Impact Factor
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ABSTRACT: We performed an analysis of early factors influencing the outcome of Cushing's disease treated by transsphenoidal pituitary surgery.
Prospective study of 29 patients who underwent transsphenoidal pituitary surgery for Cushing's disease. The prognostic value of preoperative and operative variables, histological findings and serum cortisol (measured at 8:00 a.m. the day after surgery) were analyzed.
Of the 29 patients included in this study, 26 achieved postoperative remission while in 3 patients treatment failed. Tumor was identified at histology in 92.3% patients in the remission group and in 33.3% in the failure group, this difference being significant (p = 0.03). Median postoperative cortisol levels were 95.8 nmol/l in the remission group and 676 nmol/l in the failure group, this difference being significant (p = 0.024). Serum cortisol of 600 nmol/l correctly classified the remission and failure groups with a sensitivity of 100% and a specificity of 96%.
In our experience, no identification of an adenoma at histology and an early postoperative cortisol level higher than 600 nmol/l after transsphenoidal pituitary surgery for Cushing's disease was associated with a high risk of failed treatment.
Medicina Clínica 04/2007; 128(9):330-2. · 1.38 Impact Factor
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ABSTRACT: The aim of this study was to estimate the accuracy of routine magnetic resonance (MR) imaging studies in the classification of brain tumors in terms of both cell type and grade of malignancy.
The authors retrospectively assessed the correlation between neuroimaging classifications and histopathological diagnoses by using multicenter database records from 393 patients with brain tumors. An ontology was devised to establish diagnostic agreement. Each tumor category was compared with the corresponding histopathological diagnoses by dichotomization. Sensitivity, specificity, positive and negative predictive values (PPVs and NPVs, respectively), and the Wilson 95% confidence intervals (CI) for each were calculated. In routine reporting of MR imaging examinations, tumor types and grades were classified with a high specificity (85.2-100%); sensitivity varied, depending on the tumor type and grade, alone or in combination. The recognition of broad diagnostic categories (neuroepithelial or meningeal lesions) was highly sensitive, whereas when both detailed type and grade were considered, sensitivity diverged, being highest in low-grade meningioma (sensitivity 100%, 95% CI 96.2-100.0%) and lowest in high-grade meningioma (sensitivity 0.0%, 95% CI 0.0-65.8%) and low-grade oligodendroglioma (sensitivity 15%, 95% CI 5.2-36.0%). In neuroepithelial tumors, sensitivity was inversely related to the precision in reporting of grade and cellular origin; "glioma" was a frequent neuroimaging classification associated with higher sensitivity in the corresponding category. The PPVs varied among categories, in general being greater than their prevalence in this dataset. The NPV was high in all categories (69.8-100%).
The PPVs and NPVs provided in this study may be used as estimates of posttest probabilities of diagnostic accuracy using MR imaging. This study targets the need for noninvasively increasing sensitivity in categorizing most brain tumor types while retaining high specificity, especially in the differentiation of high- and low-grade glial tumor classes.
Journal of Neurosurgery 08/2006; 105(1):6-14. · 2.96 Impact Factor
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Marta Brell,
Avelina Tortosa,
Eugenia Verger,
Juan Miguel Gil,
Nuria Viñolas,
Salvador Villá, Juan José Acebes,
Lluis Caral,
Teresa Pujol,
Isidro Ferrer,
Teresa Ribalta,
Francesc Graus
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ABSTRACT: Anaplastic gliomas constitute a heterogeneous group of tumors with different therapeutic responses to adjuvant chemotherapy with alkylating agents. O6-Methylguanine-DNA methyltransferase (MGMT), a DNA repair protein, is one of the implicated factors in glioma chemoresistance. The prognostic value of MGMT remains controversial due in part to the fact that previous published studies included heterogeneous groups of patients with different tumor grades. The aim of this study was to evaluate the prognostic significance of MGMT in patients with anaplastic glioma.
Ninety-three patients with anaplastic glioma were analyzed for MGMT protein expression by immunohistochemistry. In addition, for those patients from whom a good yield of DNA was obtained (n = 40), MGMT promoter methylation profile was analyzed by methylation-specific PCR. MGMT prognostic significance was evaluated together with other well-known prognostic factors.
Fifty-one tumors (54.8%) showed nuclear staining of MGMT. There was a trend towards longer overall survival for those patients with negative MGMT immunostaining (hazard ratio, 1.66; P = 0.066). In a secondary analysis including those patients who actually received chemotherapy (n = 72), the absence of MGMT expression was independently associated with better survival (hazard ratio, 2.12; P = 0.027). MGMT promoter methylation was observed in 50% of the analyzed tumors. No statistical correlation between MGMT expression and MGMT promoter hypermethylation was observed.
Unlike previous studies, we did not find a correlation between MGMT promoter methylation and survival. However, we observed a correlation between MGMT protein expression and survival in those patients who received chemotherapy thus suggesting that the absence of MGMT expression is a positive predictive marker in patients with anaplastic glioma.
Clinical Cancer Research 08/2005; 11(14):5167-74. · 7.74 Impact Factor
