Biomarcadores radiológicos en RM para una aproximación al diagnóstico molecular en gliomas IDH-mutados (grado II y III) / MR Imaging Biomarkers for a Diagnostic Approach of IDH-mutated Gliomas (Grades II/III)

Resumen Objetivo: Analizar características por resonancia magnética (RM) de gliomas IDH-mutados (grado II y III) en base a parámetros cualitativos, a fin de valorar el rendimiento del signo del mismatch T2-FLAIR y otras características morfológicas de los tumores, en predecir el estado del 1p/19q y su reproducibilidad interobservador. Métodos Estudio retrospectivo, descriptivo y analítico sobre una cohorte de 53 gliomas IDH-mutados (grado II y III) y molecularmente definidos respecto al 1p/19q, seleccionados a partir de la base de datos de la institución, durante el periodo 2014- 2019. Dos neuroradiólogos evaluaron características imagenológicas de forma independiente y enmascarada al diagnóstico: mismatch T2-FLAIR, localización tumoral, bordes, señal, infiltración cortical e inhomogeneidad en T2. Los casos discordantes fueron evaluados por un tercer neuroradiólogo de mayor experiencia. Resultados: Treinta de 53 (56,6%) gliomas fueron no codelecionados, y 23/53 (43,4%) codelecionados. El signo del mismatch T2-FLAIR fue positivo en 16/53 (30,18%) pacientes, 15/16 (93,75%) no codelecionados y 1/16 (6,25%) codelecionado (Exacto de Fisher p = <,0001). Los dos evaluadores demostraron una concordancia interobservador casi perfecta para ese signo, κ =,907 (95% CI, 0,781 a 1,0). La especificidad y el valor predictivo positivo del signo para predecir la ausencia de la codeleción fue de un 95,7% y un 93,8% respectivamente. Discusión: La reciente actualización en la clasificación de los gliomas los clasifica acorde a su perfil molecular. En los últimos años, varios investigadores han estudiado características morfológicas por RM de los tumores con la intención de predecir las características moleculares de los mismos. Conclusión: En nuestra población, el signo del mismatch T2-FLAIR es el único biomarcador radiológico que muestra asociación estadísticamente significativa en predecir la ausencia de codeleción en los gliomas IDH-mutados (grado II y III), con una alta especificidad y un alto valor predictivo positivo.

Abstract Objective: To analyze magnetic resonance (MR) characteristics of IDH-mutated gliomas (grades II/III) utilizing qualitative parameters with the goal of assessing the performance of the T2-FLAIR mismatch sign and other morphological characteristics of tumors in predicting the 1p/19q co-deletion status as well as inter-observer reproducibility. Methods: Retrospective and descriptive study analyzing a cohort of 53 IDH-mutated lower-grade (grades II/III) gliomas with known 1p/19q co-deletion status. Patients meeting selection criteria for this study were taken from our institutional data from 2014-2019. Two neuroradiologists assessed the following imaging characteristics independently, and blinded from the diagnosis: T2-FLAIR mismatch, tumor location, borders, signal characteristics, cortical infiltration and T2* inhomogeneity. In the event of discordant interpretations, a third senior neuroradiologist also evaluated the case. Results: 23 of the 53 (43.4%) gliomas demonstrated 1p/19q co-deletion and 30 of 53 (56.6%) did not. T2-FLAIR mismatch was positive in 16 of 53 cases (30.2%) with 15 of 16 (93.8%) demonstrating no co-deletion and 1/16 (6.25%) with co-deletion (Fisher's exact p = < .0001). The two readers showed an almost perfect interreader agreement for this sign κ = 0.907 (95% CI, 0.781 to 1.0). Specificity and positive predictive value of the sign to predict the absence of co-deletion was 95.7% and 93.8% respectively. Discussion: The recent update in classification of lower-grade gliomas segregates gliomas according to molecular profile. In the recent past, many researchers have studied MR morphologic characteristics of these tumors with the intention of predicting molecular features of said tumors Conclusion: In our patient population, T2-FLAIR mismatch sign is the only radiologic biomarker that shows statistically significant association with the absence of 1p/19q co-deletion in lower-grade gliomas, with high specificity and positive predictive value.

White cord syndrome in a pediatric patient: A case report and review.

White cord syndrome is a rare condition involving sudden neurological deterioration following a decompressive cervical spinal surgery and characterized by the appearance of hyperintensity on T2-weighted magnetic resonance imaging. We present a report of a pediatric male patient who presented with the condition. This case shows that white cord syndrome can also be present in pediatric patients. We provide a brief review of the literature highlighting the main radiologic findings.

Diagnosis of Rapidly Progressive Dementia in a Referral Center in Argentina.

INTRODUCTION: Rapidly progressive dementia (RPD) is a broadly defined clinical syndrome. Our aim was to describe clinical and ancillary study findings in patients with RPD and evaluate their diagnostic performance for the identification of nonchronic neurodegenerative rapidly progressive dementia (ncnRPD). METHODS: We reviewed clinical records and ancillary methods of patients evaluated for RPD at our institution in Buenos Aires, Argentina from 2011 to 2017. We compared findings between chronic neurodegenerative RPD and ncnRPD and evaluated the diagnostic metrics using receiver operating characteristic curves. RESULTS: We included 104 patients with RPD, 29 of whom were chronic neurodegenerative RPD and 75 of whom were ncnRPD. The 6-month time to dementia cutpoint had a sensitivity of 89% and specificity of 100% for ncnRPD, with an area under the receiver operating characteristic curve of 0.965 (95% confidence interval=0.935-0.99; P<0.001). A decision tree that included time to dementia, brain magnetic resonance imaging, and cerebrospinal fluid analysis identified ncnRPD patients with a sensitivity of 100%, specificity of 79%, positive predictive value of 93%, and negative predictive value of 100% overall. DISCUSSION: RPD is a clinical syndrome that comprises different diagnoses, many of them for treatable diseases. Using the time to dementia, brain magnetic resonance imaging, and cerebrospinal fluid analysis when triaging these patients could help identify those diseases that need to be studied more aggressively.

Lumbosacral plexus root thickening: Establishing normal root dimensions using magnetic resonance neurography.

Disorders affecting the lumbosacral plexus (LSP) can alter root diameter. Our aim was to determine normal LSP nerve root dimensions using magnetic resonance neurography (MRN). Eleven asymptomatic patients (ages: 18-53, mean: 34 years) underwent MRN of the LSP on a 3 T scanner with an 8-channel torso-PA coil. IDEAL T2-weighted images were acquired and nerve root dimensions were measured from the second lumbar (L2) to the first sacral (S1) vertebrae on the coronal plane, 5 mm from the dorsal root ganglion (DRG). Root size was recorded by three separate groups of radiologists with different levels of expertise. Additional LSP-MRN images were acquired from a fresh-frozen cadaver specimen using the same scanner and parameters identical to those described above. Subsequently, two experienced anatomists dissected and measured the LSP roots at exactly the same distance from the DRG, using an electronic caliper. Mean root size values recorded (± standard deviation) in the asymptomatic patients were as follows: L2: 3.12 mm (±0.92), L3: 4.29 mm (±0.95), L4: 5.13 mm (±0.79), L5: 5.29 mm (±0.9), and S1: 5.38 mm (±0.7). The correlation coefficients were 0.72 between the patient and cadaver MRN results and 0.79 between the patient and dissected cadaver MRN results. Inter-observer agreements were 0.73 among the radiologist groups and 0.87 between the anatomists conducting dissections. We believe MRN provides reliable assessments of LSP root thickness. More extensive studies should be conducted to confirm the results described here. Clin. Anat. 31:782-787, 2018. © 2018 Wiley Periodicals, Inc.

MIP Improves Detection of Brain Metastases.

PURPOSE: This study aimed to compare the sensitivity for detection of brain metastases using postcontrast 3-dimensional, T1W-gradient echo sequence (3DT1W) and maximum intensity projections (MIPs) obtained from the same data set. MATERIALS AND METHODS: A prospective analysis of patients with known brain metastases was performed. We compared 1-mm postcontrast 3DT1W with 6-mm MIP reconstructions obtained from the same images (MIP-3DT1) in 95 patients using 1.5 (42 patients) and 3 T (53 patient). Two independent readers analyzed all studies and the examinations were presented in anonymized and random fashion for a total of 190 interpretations per observer. One reader had more than 20 years of experience and the second reader had 1 year of experience. RESULTS: The least experienced observer found 542 brain metastases on postcontrast non-MIP 3DT1W and 605 with the MIP-3DT1 technique. For this observer, use of MIP resulted in increased number of detected metastases in 36% of patients regardless of field strength. The more experienced observer found 589 brain metastases on non-MIP 3DT1W and 621 with the MIP-3DT1 technique and the use of the latter also resulted in increased detection of metastases in 33% of patients regardless of field strength. CONCLUSIONS: In our study, we found that using MIP-3DT1 reconstructions of previously obtained postcontrast 3DT1W improved detection of brain metastases. This improvement was experienced by both the junior and experienced neuroradiologists and was also better at 3.0 T than at 1.5 T.