Neurologic Involvement in COVID-19: Cause or Coincidence? A Neuroimaging Perspective

Despite a large cohort of 103 patients with COVID-19, the authors found a large number of symptomatic patients with negative neuroimaging findings, and no conclusions can be drawn concerning concrete associations between neuroimaging and COVID-19. The rapid spread of the coronavirus disease 2019 (COVID-19) pandemic has shaken hospitals worldwide. Some authors suggest that neurologic involvement could further complicate the disease. This descriptive study is a cross-sectional review of 103 patients diagnosed with COVID-19 who underwent neuroimaging (of a total of 2249 patients with COVID-19 in our center). Analyzed variables were neurologic symptoms and acute imaging findings. The most frequent symptoms that motivated neuroimaging examinations were mild nonfocal neurologic symptoms, code stroke (refers to patients presenting with signs and symptoms of stroke whose hyperacute assessment and care is prioritized), focal neurologic symptoms, postsedation encephalopathy, and seizures. No cases of encephalitis or direct central nervous system involvement were detected. Thirteen patients presented with acute ischemic events, and 7, with hemorrhagic events; however, most reported multiple vascular risk factors. Despite the large cohort of patients with COVID-19, we found a large number of symptomatic patients with negative neuroimaging findings, and no conclusions can be drawn concerning concrete associations between neuroimaging and COVID-19

Imaging of skull vault tumors in adults

The skull vault, formed by the flat bones of the skull, has a limited spectrum of disease that lies between the fields of neuro- and musculoskeletal radiology. Its unique abnormalities, as well as other ubiquitous ones, present particular features in this location. Moreover, some benign entities in this region may mimic malignancy if analyzed using classical bone-tumor criteria, and proper patient management requires being familiar with these presentations. This article is structured as a practical review offering a systematic diagnostic approach to focal calvarial lesions, broadly organized into four categories: (1) pseudolesions: arachnoid granulations, meningo-/encephaloceles, vascular canals, frontal hyperostosis, parietal thinning, parietal foramina, and sinus pericrani; (2) lytic: fibrous dysplasia, epidermal inclusion and dermoid cysts, eosinophilic granuloma, hemangioma, aneurysmal bone cyst, giant cell tumor, metastasis, and myeloma; (3) sclerotic: osteomas, osteosarcoma, and metastasis; (4) transdiploic: meningioma, hemangiopericytoma, lymphoma, and metastasis, along with other less common entities. Tips on the potential usefulness of functional imaging techniques such as MR dynamic susceptibility (T2*) perfusion, MR spectroscopy, diffusion-weighted imaging, and PET imaging are provided

Precise enhancement quantification in post-operative MRI as an indicator of residual tumor impact is associated with survival in patients with glioblastoma

Glioblastoma is the most common primary brain tumor. Standard therapy consists of maximum safe resection combined with adjuvant radiochemotherapy followed by chemotherapy with temozolomide, however prognosis is extremely poor. Assessment of the residual tumor after surgery and patient stratification into prognostic groups (i.e., by tumor volume) is currently hindered by the subjective evaluation of residual enhancement in medical images (magnetic resonance imaging [MRI]). Furthermore, objective evidence defining the optimal time to acquire the images is lacking. We analyzed 144 patients with glioblastoma, objectively quantified the enhancing residual tumor through computational image analysis and assessed the correlation with survival. Pathological enhancement thickness on post-surgical MRI correlated with survival (hazard ratio: 1.98, p < 0.001). The prognostic value of several imaging and clinical variables was analyzed individually and combined (radiomics AUC 0.71, p = 0.07; combined AUC 0.72, p < 0.001). Residual enhancement thickness and radiomics complemented clinical data for prognosis stratification in patients with glioblastoma. Significant results were only obtained for scans performed between 24 and 72 h after surgery, raising the possibility of confounding non-tumor enhancement in very early post-surgery MRI. Regarding the extent of resection, and in agreement with recent studies, the association between the measured tumor remnant and survival supports maximal safe resection whenever possible

Perilesional edema in brain metastases as predictive factor of response to systemic therapy in non-small cell lung cancer patients: a preliminary study

Background: The significance of upfront systemic therapies as an alternative to whole brain radiotherapy (WBRT) for multiple brain metastases (BM) is debatable. Our purpose is to investigate if peritumoral edema could predict the intracranial response to systemic chemotherapy (chemo) in patients with advanced non-squamous non-small cell lung cancer (non-SQ-NSCLC) and synchronous multiple BM. Methods: In this observational cohort study, we evaluated the outcome of 28 patients with multiple BM (≥3) treated with chemo based on cisplatin/carboplatin plus pemetrexed (chemo, group A, n=17) or WBRT plus subsequent chemo (group B, n=11). The intracranial response, assessed by the response assessment neuro-oncology (RANO) BM criteria, was correlated with the degree of BM-associated edema estimated by the maximum diameter ratio among fluid attenuated inversion recovery (FLAIR) and gadolinium-enhanced T1WI (T1Gd) per each BM at the baseline brain magnetic resonance imaging (MRI). Results: No differences were observed in baseline characteristics between both groups, except for the number of patients under steroid treatment that was clearly superior in group B (P=0.007). Median OS was similar between groups. Regarding FLAIR/T1Gd ratio (F/Gd), patients treated with chemo alone exhibited significantly higher values (P=0.001) in those who developed intracranial progression disease (PD) (2.80±0.32 mm), compared with those who achieved partial response (PR) (1.30±0.11 mm) or stable disease (SD) (1.35±0.09 mm). In patients treated with WBRT, F/Gd ratio was not predictive of response. Conclusions: Peritumoral edema estimated by F/Gd ratio appears a promising predictive tool to identify oligosymptomatic patients with multiple BM in whom WBRT can be postponed

Espectrocopia por resonancia magnética de protón en el diagnóstico de tumores cerebrales

[spa] La Espectroscopia por Resonancia Magnética de Protón (ERM 1H) es una técnica no invasiva de diagnóstico que, utilizando el mismo material que los estudios convencionales de imagen por RM, estudia el contenido bioquímico de los tejidos. De esta manera permite valorar el estado metabólico de los tejidos. En esta tesis se aborda el tema de la aplicación clínica de la espectroscopia por resonancia magnética de protón (ERM 1H) en el diagnóstico de los tumores cerebrales. Contiene tres artículos publicados en European Radiology, Radiology y Neuroradiology en los años 2002 y 2003. En ellos se propone un método para clasificar los tumores cerebrales en base a sus características en ERM 1H. Para ello se utilizan los percentiles de 10 y 90% de determinadas resonancias, dependiendo de los casos, como puntos de corte en diversos algoritmos. Los algoritmos se adaptan en cada trabajo dependiendo de la pregunta a responder. En el primer trabajo (Majós et al, European Radiology 2003) se trabaja la clasificación de los tumores más frecuentes en cuatro grupos (1-meningioma, 2-astrocitoma de bajo grado, 3-astrocitoma anaplásico, y 4-glioblastoma+metástasis). Los resultados, validados en un grupo de test, son de 82% clasificaciones correctas. En el segundo trabajo (Majós et al, Radiology 2002) se estudia un grupo tumoral menos prevalente: los Tumores Neuroectodérmicos Primitivos (TNEP) en adultos. Se estudian sus características espectroscópicas y los resultados que se obtienen al aplicar estas características en el diagnóstico diferencial con los tumores cerebrales más frecuentes en el adulto (meningioma, astrocitoma de bajo grado, astrocitoma anaplásico, glioblastoma y metástasis). Los resultados obtenidos, validados también en un grupo test, son de 78% clasificaciones correctas, 13% clasificaciones incorrectas y 9% casos inclasificables. En este artículo se concluye que la ERM 1H proporciona información útil para la diferenciación clínica entre TNEP y los tumores cerebrales más frecuentes en el adulto. En el tercer artículo (Majós et al, Neuroradiology 2003) se estudian los meningiomas de aspecto radiológico atípico. Los autores estudian en profundidad las características espectroscópicas de los meningiomas y los aspectos que pueden ser de mayor utilidad para diferenciarlos de los tumores cerebrales más frecuentes. Estos aspectos se aplican en un algoritmo similar al elaborado en los otros dos trabajos. En un segundo tiempo se identifican los meningiomas que por su aspecto radiológico pueden ser considerados atípicos. Estos meningiomas constituyen un 14% del total de meningiomas (5/37). Se les aplica el algoritmo elaborado con el global de meningiomas para realizar los diagnósticos diferenciales surgidos a partir de la valoración de las imágenes, obteniendo una clasificación correcta en 4 de 5 casos (80%) y 10 de 12 procedimientos de diagnóstico diferencial (83%). La conclusión de este trabajo es que la ERM 1H puede ser aplicada con éxito en tumores en que el diagnóstico de meningioma no está suficientemente claro con los estudios de imagen. En global estos trabajos aportan una valoración de la utilidad clínica de la espectroscopia, concluyendo que su aplicación puede ser útil en determinados casos. Se sugiere la ERM 1H como una técnica adicional a ser utilizada para mejorar el diagnóstico prequirúrgico de los tumores cerebrales, máxime teniendo en cuenta que se trata de un método no invasivo y que puede realizarse en el mismo procedimiento que el estudio por RM convencional

The INTERPRET Decision-Support System version 3.0 for evaluation of Magnetic Resonance Spectroscopy data from human brain tumours and other abnormal brain masses

Background: Proton Magnetic Resonance (MR) Spectroscopy (MRS) is a widely available technique for those clinical centres equipped with MR scanners. Unlike the rest of MR-based techniques, MRS yields not images but spectra of metabolites in the tissues. In pathological situations, the MRS profile changes and this has been particularly described for brain tumours. However, radiologists are frequently not familiar to the interpretation of MRS data and for this reason, the usefulness of decision-support systems (DSS) in MRS data analysis has been explored. Results: This work presents the INTERPRET DSS version 3.0, analysing the improvements made from its first release in 2002. Version 3.0 is aimed to be a program that 1(st), can be easily used with any new case from any MR scanner manufacturer and 2(nd), improves the initial analysis capabilities of the first version. The main improvements are an embedded database, user accounts, more diagnostic discrimination capabilities and the possibility to analyse data acquired under additional data acquisition conditions. Other improvements include a customisable graphical user interface (GUI). Most diagnostic problems included have been addressed through a pattern-recognition based approach, in which classifiers based on linear discriminant analysis (LDA) were trained and tested. Conclusions: The INTERPRET DSS 3.0 allows radiologists, medical physicists, biochemists or, generally speaking, any person with a minimum knowledge of what an MR spectrum is, to enter their own SV raw data, acquired at 1.5 T, and to analyse them. The system is expected to help in the categorisation of MR Spectra from abnormal brain masses