Aristides A. Capizzano

White matter hyperintensities are significantly associated with cortical atrophy in Alzheimer's disease.

Background and objective: Methodological variability in the assessment of white matter hyperintensities (WMH) in dementia may explain inconsistent reports of its prevalence and impact on cognition. We used a method of brain MRI segmentation for quantifying both tissue and WMH volumes in Alzheimer’s disease (AD) and examined the association between WMH and structural and cognitive variables. Methods: A consecutive series of 81 patients meeting NINCDS-ADRDA criteria for probable AD was studied. Nineteen healthy volunteers of comparable age served as the control group. Patients had a complete neurological and neuropsychological evaluation, and a three dimensional MRI was obtained. Images were segmented into grey matter, white matter, and cerebrospinal fluid. WMH were edited on segmented images, and lobar assignments were based on Talairach coordinates. Results: Mild and moderate to severe AD patients had significantly more WMH than controls (p<0.05). WMH preferentially involved the frontal lobes (70%), were inversely correlated with grey matter cortical volume (R2 = 0.23, p<0.001), and were significantly associated with vascular risk factors and with a worse performance on memory tasks. Conclusion: Objective measurements of tissue volumes in AD demonstrated that WMH are significantly related to cortical atrophy and neuropsychological impairment.

In vivo proton magnetic resonance spectroscopy in patients with mood disorders: a technically oriented review.

Proton MR spectroscopy (1HMRS) has been extensively used among mood disorders patients. A review of the published literature in 1HMRS studies of mood disorders was carried out for the period 1991 to July 2006. Of 71 1HMRS studies, 77.5% were done at 1.5T and 66.2% used single voxel sequences (SVS), implying limitations of spectral resolution and anatomic coverage, respectively. In all, 47.9% of studies relied on creatine (Cr) as internal signal standard, although Cr changes were reported in major depression (MD). Most reported metabolic alterations related to mood state affected the left frontal lobe. Depressed adult and pediatric MD patients had reduced glutamate (Glu) in frontal lobe regions, which reversed with successful treatment. A consistent reduction of N‐acetyl‐aspartate (NAA) was reported in the hippocampal formation among bipolar disorder (BD) patients, along with an increment in frontal Glu. The differences in results of 1HMRS studies in mood disorders reflect heterogeneity of technical factors and subject selection. Future studies should benefit from higher spectral resolution and more extensive anatomic coverage as well as standardized data‐processing protocols and subject selection criteria. J. Magn. Reson. Imaging 2007.

3-Dimensional magnetic resonance spectroscopic imaging at 3 Tesla for early response assessment of glioblastoma patients during external beam radiation therapy.

PURPOSE To evaluate the utility of 3-dimensional magnetic resonance (3D-MR) proton spectroscopic imaging for treatment planning and its implications for early response assessment in glioblastoma multiforme. METHODS AND MATERIALS Eighteen patients with newly diagnosed, histologically confirmed glioblastoma had 3D-MR proton spectroscopic imaging (MRSI) along with T2 and T1 gadolinium-enhanced MR images at simulation and at boost treatment planning after 17 to 20 fractions of radiation therapy. All patients received standard radiation therapy (RT) with concurrent temozolomide followed by adjuvant temozolomide. Imaging for response assessment consisted of MR scans every 2 months. Progression-free survival was defined by the criteria of MacDonald et al. MRSI images obtained at initial simulation were analyzed for choline/N-acetylaspartate ratios (Cho/NAA) on a voxel-by-voxel basis with abnormal activity defined as Cho/NAA ≥2. These images were compared on anatomically matched MRSI data collected after 3 weeks of RT. Changes in Cho/NAA between pretherapy and third-week RT scans were tested using Wilcoxon matched-pairs signed rank tests and correlated with progression-free survival, radiation dose and location of recurrence using Cox proportional hazards regression. RESULTS After a median follow-up time of 8.6 months, 50% of patients had experienced progression based on imaging. Patients with a decreased or stable mean or median Cho/NAA values had less risk of progression (P<.01). Patients with an increase in mean or median Cho/NAA values at the third-week RT scan had a significantly greater chance of early progression (P<.01). An increased Cho/NAA at the third-week MRSI scan carried a hazard ratio of 2.72 (95% confidence interval, 1.10-6.71; P=.03). Most patients received the prescription dose of RT to the Cho/NAA ≥2 volume, where recurrence most often occurred. CONCLUSION Change in mean and median Cho/NAA detected at 3 weeks was a significant predictor of early progression. The potential impact for risk-adaptive therapy based on early spectroscopic findings is suggested.

Long-term neuropsychological, neuroanatomical, and life outcome in hippocampal amnesia

Focal bilateral hippocampal damage typically causes severe and selective amnesia for new declarative information (facts and events), a cognitive deficit that greatly impacts the ability to live a normal, fully independent life. We describe the case of 1846, a 48-year-old woman with profound hippocampal amnesia following status epilepticus and an associated anoxic episode at age 30. Patient 1846 has undergone extensive neuropsychological testing on many occasions over the 18 years since her injury, and we present data indicating that her memory impairment has remained severe and stable during that time. New, high-resolution, structural MRI studies of 1846s brain reveal substantial bilateral hippocampal atrophy resembling that of other well-known amnesic patients. In spite of severe amnesia 1846 lives a full and mostly independent adult life, facilitated by an extensive social support network of family and friends. Her case provides an example of a rare and unlikely positive outcome in the face of severe memory problems.

Limbic Metabolic Abnormalities in Remote Traumatic Brain Injury and Correlation With Psychiatric Morbidity and Social Functioning

The aim of this study was to investigate limbic metabolic abnormalities in remote traumatic brain injury (TBI) and their psychiatric correlates. Twenty patients and 13 age-matched comparison subjects received complete psychiatric evaluation and brain MRI and MR spectroscopy at 3 Tesla. Patients had reduced NAA to creatine ratio in the left hippocampus relative to comparison subjects (mean=1.3 [SD=0.21] compared with mean=1.55 [SD=0.21]; F=10.73, df=1, 30, p=0.003), which correlated with the Social Functioning Examination scores (r(s)=-0.502, p=0.034). Furthermore, patients with mood disorders had reduced NAA to creatine ratio in the left cingulate relative to patients without mood disorders (1.47 compared with 1.68; F=3.393, df=3, 19, p=0.044). Remote TBI displays limbic metabolic abnormalities, which correlate to social outcome and psychiatric status.

Viral infections and white matter lesions.

This article discusses imaging findings in virus-related infectious and noninfectious encephalitis/encephalopathy with white matter involvement, as well as the differential diagnosis based on the characteristic distribution. Acute viral encephalitis/encephalopathy is a medical emergency. Prompt introduction of treatment has a significant influence on survival and the extent of permanent brain injury. Differentiation between infectious and noninfectious central nervous system involvement is paramount. Neuroimaging provides many clues for the specific diagnosis. Understanding the underlying disorder and pathophysiology is important for the interpretation of the images and therefore the treatment.

Uncommon causes of cerebrovascular dementia

BACKGROUND The concept of Binswangers disease (BD) remains unclear and may not constitute a useful diagnostic category. However, cognitive decline may be present in a proportion of patients with subarachnoid hemorrhages (SAH) or subdural hematomas (SH). METHOD We provide a critical review of the concept of BD and summarize the main findings on the association between SAH, SH and cognitive decline. RESULTS AND CONCLUSIONS BD was originally identified as a type of dementia different from neurosyphilis and with characteristic white matter atrophy. The phenomenology of BD is currently construed around the concept of frontosubcortical dementia, but the validity of this construct is unclear. Patients with SAH frequently develop a variety of cognitive and behavioral problems that usually result in poor psychosocial adjustment and poor quality of life. SH is a rare cause of progressive cognitive impairment. A proportion of patients (particularly functionally impaired old individuals) are at a high risk for cognitive deficits after surgical drainage of the hematoma.

Role of the temporal pole in temporal lobe epilepsy seizure networks: an intracranial electrode investigation

OBJECTIVE A convergence of clinical research suggests that the temporal pole (TP) plays an important and potentially underappreciated role in the genesis and propagation of seizures in temporal lobe epilepsy (TLE). Understanding its role is becoming increasingly important because selective resections for medically intractable TLE spare temporopolar cortex (TPC). The purpose of this study was to characterize the role of the TPC in TLE after using dense electrocorticography (ECoG) recordings in patients undergoing invasive monitoring for medically intractable TLE. METHODS Chronic ECoG recordings were obtained in 10 consecutive patients by using an array customized to provide dense coverage of the TP as part of invasive monitoring to localize the epileptogenic zone. All patients would eventually undergo cortico-amygdalohippocampectomy. A retrospective review of the patient clinical records including ECoG recordings, neuroimaging studies, neuropathology reports, and clinical outcomes was performed. RESULTS In 7 patients (70%), the TP was involved at seizure onset; in 7 patients (70%), there were interictal discharges from the TP; and in 1 case, there was early spread to the TP. Seizure onset in the TP did not necessarily correlate with preoperative neuroimaging abnormalities of the TP. CONCLUSIONS These data demonstrate that TPC commonly plays a crucial role in temporal lobe seizure networks. Seizure onset from the TP would not have been predicted based on available neuroimaging data or interictal discharges. These findings illustrate the importance of thoroughly considering the role of the TP prior to resective surgery for TLE, particularly when selective mesial resection is being considered.

Cerebrovascular manifestations in neurosarcoidosis: how common are they and does perivascular enhancement matter?

AIM To determine the occurrence of ischaemic and haemorrhagic events in patients with neurosarcoidosis at presentation and follow-up and to evaluate its association with perivascular enhancement. MATERIALS AND METHODS The MRI findings in patients with neurosarcoidosis who presented to our institute from 2002-2017 were retrospectively reviewed, with emphasis on cerebrovascular events. A chi-squared test was used to evaluate the statistical association with presence of perivascular enhancement. RESULTS A total of 49 patients (32 females and 17 males) were analysed. Ischaemic events were noted in four patients at presentation while parenchymal haemorrhages occurred in three patients. The combined occurrence of cerebrovascular events (CVEs) at presentation was 14%. On follow-up, three additional patients developed ischaemic infarcts, of which, one patient had parenchymal haemorrhage at presentation. Additionally, one patient also developed new parenchymal haemorrhages. In total, 10 patients in current cohort developed CVEs, either at presentation or on follow-up. Perivascular enhancement was seen in 50% of patients with cerebrovascular events and 18% of patients with neurosarcoidosis, but no CVEs. This was statistically significant (p<0.05). CONCLUSION CVEs in patients with neurosarcoidosis are more common than previously reported and appear to be significantly related to the presence of perivascular enhancement on imaging.

Genetic Syndromes Associated with Central Nervous System Tumors.

Several genetic tumor syndromes have associated central nervous system (CNS) neoplasms. The spectrum of syndromes that have intracranial tumor manifestations includes ataxia telangiectasia, Cowden syndrome, familial adenomatous polyposis, hereditary non-polyposis-related colorectal cancer, Li-Fraumeni syndrome, Gorlin syndrome, neurofibromatosis types 1 and 2, multiple endocrine neoplasia type 1, tuberous sclerosis complex, von Hippel-Lindau disease, and Turcot syndrome. Many of these disorders are inherited in an autosomal dominant fashion, and identification of the associated genetic defects has led to improved understanding of the molecular pathways involved in tumorigenesis, helping pave the way to the emergence of molecularly targeted therapeutics. Recognition of individuals and families at risk for such tumors is critical to improve clinical care and optimize proper genetic counseling. To contribute effectively, the radiologist should recognize the common varieties of tumors and characteristic neuroimaging manifestations seen in each familial syndrome. A fundamental understanding of the genetics and molecular pathogenesis of these tumors is critical in understanding the development of specific and unique tumors in each entity. In this article, we review the most common genetic tumor syndromes with associated intracranial neoplasms, with emphasis on recent genetic and molecular biology data, clinical manifestations, and management as well as the controversies and current recommendations for screening and surveillance. A detailed overview of all the major and pertinent CNS imaging features will be elucidated, including computed tomography, magnetic resonance imaging, and, in relevant cases, magnetic resonance spectroscopy. ©RSNA, 2016.