Antônio Carlos Martins Maia Júnior

Focal transient lesion in the splenium of the corpus callosum in three non-epileptic patients.

IntroductionWe analyzed the imaging features of transient focal lesions in the splenium of the corpus callosum (SCC) in non-epileptic patients receiving antiepileptic drugs (AEDs).MethodsWe identified signal abnormalities in the SCC in three non-epileptic patients, all of them receiving AEDs. We examined two of these patients with multiplanar magnetic resonance (MR) imaging using 1.0-T equipment including fluid-attenuated inversion recovery (FLAIR), T2-weighted (TSE) and T1-weighted (SE) sequences before and after injection of contrast agent. The third patient was studied using 1.5-T equipment with the same sequences. Additionally, a T1 SE sequence with a magnetization transfer contrast pulse off resonance (T1 SE/MTC), diffusion-weighted imaging (EPI-DWI) and apparent diffusion coefficient (ADC) maps were obtained.ResultsWe observed an identical pattern of imaging abnormalities in all patients characterized by round lesions, hyperintense on FLAIR and hypointense on T1 SE images, located in the central portion of the SCC. One lesion showed homogeneous gadolinium enhancement and perilesional vasogenic edema. This particular lesion showed restricted diffusion confirmed on the ADC map. This pattern was considered consistent with focal demyelination. Follow-up MR examinations showed complete disappearance or a clear reduction in lesion size. All patients had been treated with AEDs, but they did not show any clinical signs of toxicity, interhemispheric symptoms, or abnormal neurological findings (including seizures).ConclusionWe believe that our MR findings might be interpreted as transient lesions related to AED toxicity. They presumably resulted from focal demyelination in the central portion of the SCC.

Lactate Detection by MRS in Mitochondrial Encephalopathy: Optimization of Technical Parameters

Mitochondriopathies are a heterogeneous group of diseases with variable phenotypic presentation, which can range from subclinical to lethal forms. They are related either to DNA mutations or nuclear‐encoded mitochondrial genes that affect the integrity and function of these organelles, compromising adenosine triphosphate (ATP) synthesis. Magnetic resonance (MR) is the most important imaging technique to detect structural and metabolic brain abnormalities in mitochondriopathies, although in some cases these studies may present normal results, or the identified brain abnormalities may be nonspecific. Magnetic resonance spectroscopy (MRS) enables the detection of high cerebral lactate levels, even when the brain has normal appearance by conventional MR scans. MRS is a useful tool for the diagnosis of mitochondriopathies, but must be correlated with clinical, neurophysiological, biochemical, histological, and molecular data to corroborate the diagnosis. Our aim is to clarify the most relevant issues related to the use of MRS in order to optimize its technical parameters, improving its use in the diagnosis of mitochondriopathies, which is often a challenge.

Magnetic resonance findings in amyotrophic lateral sclerosis using a spin echo magnetization transfer sequence: preliminary report

We present the magnetic resonance (MR) findings of five patients with amyotrophic lateral sclerosis (ALS) using a spin-echo sequence with an additional magnetization transfer (MT) pulse on T1-weighted images (T1 SE/MT). These findings were absent in the control group and consisted of hyperintensity of the corticospinal tract. Moreover we discuss the principles and the use of this fast but simple MR technique in the diagnosis of ALS.

Modern techniques of magnetic resonance in the evaluation of primary central nervous system lymphoma: contributions to the diagnosis and differential diagnosis.

In addition to findings from conventional magnetic resonance imaging, modern magnetic resonance imaging techniques have provided important information about tumor metabolism, in vivo metabolite formation, water molecule diffusion, microvascular density, and blood-brain barrier permeability, all of which have improved the in vivo diagnostic accuracy of this method in the evaluation of primary central nervous system lymphoma. These nonconventional magnetic resonance techniques are useful in the clinical practice because they enhance conventional magnetic resonance imaging by reinforcing the possibility of a diagnosis and by allowing the early detection of disease recurrence. This report is a review of the most relevant contributions of nonconventional magnetic resonance techniques to the imaging diagnosis of primary central nervous system lymphoma, the differential diagnosis of this disease, and the prognosis of patients. This paper aims to describe a wide range of presentations of primary central nervous system lymphoma, their appearance in imaging, and the differential diagnoses of this disease.

Active extravasation of contrast within the hemorrhage (spot sign): a multidetector computed tomography finding that predicts growth and a worse prognosis in non-traumatic intracerebral hemorrhage

Intracerebral hemorrhage (ICH) causes high rates of disability and neurological sequelae Objective To evaluate spot signs as predictors of expansion and worse prognosis in non-traumatic ICH in a Brazilian cohort. Method We used multidetector computed tomography angiography to study 65 consecutive patients (40 men, 61.5%), with ages varying from 33 to 89 years (median age 55 years). Clinical and imaging findings were correlated with the findings based on the initial imaging. Results Of the individuals who presented a spot sign, 73.7% died (in-hospital mortality), whereas in the absence of a spot sign the mortality rate was 43.0%. Although expansion of ICH was detected in 75% of the patients with a spot sign, expansion was observed in only 9.0% of the patients who did not present a spot sign. Conclusions The spot sign strongly predicted expansion in non-traumatic ICH and an increased risk of in-hospital mortality.

Imaging of Creutzfeldt-Jakob Disease: Imaging Patterns and Their Differential Diagnosis

Diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) remains a challenge because of the large variability of the clinical scenario, especially in its early stages, which may mimic several reversible or treatable disorders. The molecular basis of prion disease, as well as its brain propagation and the pathogenesis of the illness, have become better understood in recent decades. Several reports have listed recognizable clinical features and paraclinical tests to supplement the replicable diagnostic criteria in vivo. Nevertheless, we lack specific data about the differential diagnosis of CJD at imaging, mainly regarding those disorders evolving with similar clinical features (mimicking disorders). This review provides an update on the neuroimaging patterns of sCJD, emphasizing the relevance of magnetic resonance (MR) imaging, summarizing the clinical scenario and molecular basis of the disease, and highlighting clinical, genetic, and imaging correlations in different subtypes of prion diseases. A long list of differential diagnoses produces a comprehensive pictorial review, with the aim of enabling radiologists to identify typical and atypical patterns of sCJD. This review reinforces distinguishable imaging findings and confirms diffusion-weighted imaging (DWI) features as pivotal in the diagnostic workup of sCJD, as these findings enable radiologists to reliably recognize this rare but invariably lethal disease. A probable diagnosis is justified when expected MR imaging patterns are demonstrated and CJD-mimicking disorders are confidently ruled out. ©RSNA, 2017.

Multiparametric multidetector computed tomography scanning on suspicion of hyperacute ischemic stroke: validating a standardized protocol

Multidetector computed tomography (MDCT) scanning has enabled the early diagnosis of hyperacute brain ischemia. We aimed at validating a standardized protocol to read and report MDCT techniques in a series of adult patients. The inter-observer agreement among the trained examiners was tested, and their results were compared with a standard reading. No false positives were observed, and an almost perfect agreement (Kappa>0.81) was documented when the CT angiography (CTA) and cerebral perfusion CT (CPCT) map data were added to the noncontrast CT (NCCT) analysis. The inter-observer agreement was higher for highly trained readers, corroborating the need for specific training to interpret these modern techniques. The authors recommend adding CTA and CPCT to the NCCT analysis in order to clarify the global analysis of structural and hemodynamic brain abnormalities. Our structured report is suitable as a script for the reproducible analysis of the MDCT of patients on suspicion of ischemic stroke.

Neuromyelitis Optica Spectrum Disorders: Spectrum of MR Imaging Findings and Their Differential Diagnosis

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder for which the aquaporin-4 (AQP4) water channels are the major target antigens. Advances in the understanding of NMO have clarified several points of its pathogenesis, clinical manifestations, and imaging patterns. A major advance was the discovery of the AQP4 antibody, which is highly specific for this disorder. Descriptions of new clinical and radiologic features in seropositive patients have expanded the spectrum of NMO, and the term NMO spectrum disorder (NMOSD) has been adopted. NMOSD is now included in a widening list of differential diagnoses. Acknowledgment of NMOSD imaging patterns and their mimicry of disorders has been crucial in supporting early NMOSD diagnosis, especially for unusual clinical manifestations of this demyelinating disease. This pictorial review summarizes the wide imaging spectrum of NMOSD and its differential diagnosis, as well as its historical evolution, pathophysiology, and clinical manifestations. ©RSNA, 2018.

Terson's syndrome following an aneurysmal subarachnoid hemorrhage: an imaging prognostic finding you should recognize.

Terson’s Syndrome (TS) was originally described as intraocular hemorrhage associated with aneurysmal subarachnoid hemorrhage (SAH)1. It is a consequence of sudden rise in intracranial pressure (IP) that reduces venous return to the cavernous sinus or obstruct the retinochoroidal anastomoses and central retinal vein, culminating in venous stasis and ocular hemorrhage (Figure). TS has also been reported in nonaneurysmal SAH, severe traumatic injuries or venous thrombosis2. Current literature has highlighted TS as an important life-threatening prognostic finding3,4. Recognizing TS on fundoscopy or CT is recommended and effective control of IP is imperative to reduce the risk of mortality in this critical setting5.