Browsing by Author "Castillo, M"
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- Cerebral Cavernous Malformations: Typical and Atypical Imaging CharacteristicsPublication . Kuroedov, D; Cunha, B; Pamplona, J; Castillo, M; Ramalho, JCavernous malformations (CMs) are benign vascular malformations that maybe seen anywhere in the central nervous system. They are dynamic lesions, growing or shrinking over time and only rarely remaining stable. Size varies from a few millimeters to a few centimeters. CMs can be sporadic or familial, and while most of them are congenital, de novo and acquired lesions may also be seen. Etiology is still unknown. A genetic molecular mechanism has been proposed since a cerebral cavernous malformation gene loss of function was found in both familial and sporadic lesions. Additionally, recent studies suggest that formation of CMs in humans may be associated with a distinctive bacterial gut composition (microbioma). Imaging is fairly typical but may vary according to age, location, and etiology. Follow-up is not well established because CMs patients have a highly unpredictable clinical course. Angiogenic and inflammatory mechanisms have been implicated in disease activity, as well as lesional hyperpermeability and iron deposition. Imaging and serum biomarkers of these mechanisms are under current investigation. Treatment options, including surgery or radiosurgery, are not well defined and are dependent upon multiple factors, including clinical presentation, lesion location, number of hemorrhagic events, and medical comorbidities. Our purpose is to review the imaging features of CMs based on their size, location, and etiology, as well as their differential diagnosis and best imaging approach. New insights in etiology will be briefly considered. Follow-up strategies, including serum and imaging biomarkers, and treatment options will also be discussed.
- Evidence Levels for Neuroradiology Articles: Low Agreement Among RatersPublication . Ramalho, J; Tedesqui, G; Ramalho, M; Azevedo, RS; Castillo, MBACKGROUND AND PURPOSE: Because evidence-based articles are difficult to recognize among the large volume of publications available, some journals have adopted evidence-based medicine criteria to classify their articles. Our purpose was to determine whether an evidence-based medicine classification used by a subspecialty-imaging journal allowed consistent categorization of levels of evidence among different raters. MATERIALS AND METHODS: One hundred consecutive articles in the American Journal of Neuroradiology were classified as to their level of evidence by the 2 original manuscript reviewers, and their interobserver agreement was calculated. After publication, abstracts and titles were reprinted and independently ranked by 3 different radiologists at 2 different time points. Interobserver and intraobserver agreement was calculated for these radiologists. RESULTS: The interobserver agreement between the original manuscript reviewers was -0.2283 (standard error = 0.0000; 95% CI, -0.2283 to -0.2283); among the 3 postpublication reviewers for the first evaluation, it was 0.1899 (standard error = 0.0383; 95% CI, 0.1149-0.2649); and for the second evaluation, performed 3 months later, it was 0.1145 (standard error = 0.0350; 95% CI, 0.0460-0.1831). The intraobserver agreement was 0.2344 (standard error = 0.0660; 95% CI, 0.1050-0.3639), 0.3826 (standard error = 0.0738; 95% CI, 0.2379-0.5272), and 0.6611 (standard error = 0.0656; 95% CI, 0.5325-0.7898) for the 3 postpublication evaluators, respectively. These results show no-to-fair interreviewer agreement and a tendency to slight intrareviewer agreement. CONCLUSIONS: Inconsistent use of evidence-based criteria by different raters limits their utility when attempting to classify neuroradiology-related articles.
- Gadolinium-Based Contrast Agent Accumulation and Toxicity: an UpdatePublication . Ramalho, J; Semelka, RC; Ramalho, M; Nunes, RH; Alobaidy, M; Castillo, MIn current practice, gadolinium-based contrast agents have been considered safe when used at clinically recommended doses in patients without severe renal insufficiency. The causal relationship between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with renal insufficiency resulted in new policies regarding the administration of these agents. After an effective screening of patients with renal disease by performing either unenhanced or reduced-dose-enhanced studies in these patients and by using the most stable contrast agents, nephrogenic systemic fibrosis has been largely eliminated since 2009. Evidence of in vivo gadolinium deposition in bone tissue in patients with normal renal function is well-established, but recent literature showing that gadolinium might also deposit in the brain in patients with intact blood-brain barriers caught many individuals in the imaging community by surprise. The purpose of this review was to summarize the literature on gadolinium-based contrast agents, tying together information on agent stability and animal and human studies, and to emphasize that low-stability agents are the ones most often associated with brain deposition.
- Signal Intensity Change on Unenhanced T1-Weighted Images in Dentate Nucleus Following Gadobenate Dimeglumine in Patients With and Without Previous Multiple Administrations of GadodiamidePublication . Ramalho, J; Semelka, RC; AlObaidy, M; Ramalho, M; Nunes, RH; Castillo, MOBJECTIVES: To evaluate the impact of previous administration of gadodiamide and neural tissue gadolinium deposition in patients who received gadobenate dimeglumine. METHODS: Our population included 62 patients who underwent at least three administrations of gadobenate dimeglumine, plus an additional contrast-enhanced last MRI for reference, divided into two groups: group 1, patients who in addition to gadobenate dimeglumine administrations had prior exposure to multiple doses of gadodiamide; group 2, patients without previous exposure to other gadolinium-based contrast agent (GBCAs). Quantitative analysis was performed on the first and last gadobenate dimeglumine MRIs in both groups. Dentate nucleus-to-middle cerebellar peduncle signal intensity ratios (DN/MCP) and relative change (RC) in signal over time were calculated and compared between groups using generalized additive model. RESULTS: Group 1 showed significant increase in baseline and follow-up DN/MCP compared to group 2 (p < 0.0001). The RC DN/MCP showed a non-statistically significant trend towards an increase in patients who underwent previous gadodiamide (p = 0.0735). CONCLUSION: There is increased T1 signal change over time in patients who underwent gadobenate dimeglumine and had received prior gadodiamide compared to those without known exposure to previous gadodiamide. A potentiating effect from prior gadodiamide on subsequent administered gadobenate dimeglumine may occur. KEY POINTS: • Neural gadolinium deposition is associated with multiple administrations of less stable GBCAs. • Less stable GBCA effect on subsequent more stable GBCA administrations is undetermined. • Significant increase of DN/MCP was seen in patients with previous gadodiamide exposure. • RC DN/MCP showed a non-significant increase in patients who received previous gadodiamide. • Potentiating effects from prior gadodiamide on subsequent administered gadobenate dimeglumine may occur.
- Toxic and Metabolic MyelopathiesPublication . Ramalho, J; Hoffmann Nunes, R; da Rocha, AJ; Castillo, MMyelopathy describes any neurologic deficit related to the spinal cord. It is most commonly caused by its compression by neoplasms, degenerative disc disease, trauma, or infection. Less common causes of myelopathy include spinal cord tumors, infection, inflammatory, neurodegenerative, vascular, toxic, and metabolic disorders. Conditions affecting the spinal cord must be recognized as early as possible to prevent progression that may lead to permanent disability. Biopsy is rarely performed, thus the diagnosis and management rely on patient׳s history, physical examination, laboratory results, and imaging findings. Here we review the clinical presentations, pathophysiological mechanisms, and magnetic resonance imaging findings of myelopathies related to metabolic or toxic etiologies.