Background Neuroimaging studies of autosomal dominant Alzheimer’s disease (ADAD) enable characterization of the trajectories of cerebral amyloid-β (Aβ) and tau accumulation in the decades prior to clinical symptom onset. Longitudinal rates of regional tau accumulation measured with positron emission tomography (PET) and their relationship with other biomarker and cognitive changes remain to be fully characterized in ADAD. Methods Fourteen ADAD mutation carriers (Presenilin-1 E280A) and 15 age-matched non-carriers from the Colombian kindred underwent 2–3 sessions of Aβ (11C-Pittsburgh compound B) and tau (18F-flortaucipir) PET, structural magnetic resonance imaging, and neuropsychological evaluation over a 2–4-year follow-up period. Annualized rates of change for imaging and cognitive variables were compared between carriers and non-carriers, and relationships among baseline measurements and rates of change were assessed within carriers. Results Longitudinal measurements were consistent with a sequence of ADAD-related changes beginning with Aβ accumulation (16 years prior to expected symptom onset, EYO), followed by entorhinal cortex (EC) tau (9 EYO), neocortical tau (6 EYO), hippocampal atrophy (6 EYO), and cognitive decline (4 EYO). Rates of tau accumulation among carriers were most rapid in parietal neocortex (~ 9%/year). EC tau PET signal at baseline was a significant predictor of subsequent neocortical tau accumulation and cognitive decline within carriers. Conclusions Our results are consistent with the sequence of biological changes in ADAD implied by cross-sectional studies and highlight the importance of EC tau as an early biomarker and a potential link between Aβ burden and neocortical tau accumulation in ADAD.

BACKGROUND AND PURPOSE: Moebius sequence comprises a spectrum of brain congenital malformations predominantly affecting the function of multiple cranial nerves. Reported neuroimaging findings are heterogeneous and based on case reports or small case series. Our goal was to describe the neuroimaging findings of Moebius sequence in a large population of patients scanned with MR imaging. MATERIALS AND METHODS: An observational cross-sectional study was performed to assess brain MR imaging findings in 38 patients with Moebius syndrome studied between 2013 and 2016. RESULTS: Retrospective analysis of MR imaging studies showed flattening of the floor of the fourth ventricle floor secondary to a bilateral absent facial colliculus in 38 patients (100%) and unilateral absence in 1. A hypoplastic pons was found in 23 patients (60.5%). Mesencephalic malformations consisted of tectal beaking in 15 patients (39.5%) and increased anteroposterior midbrain diameter with a shallow interpeduncular cistern in 12 (31.6%). Infratentorial arachnoid cysts were found in 5 patients (13.2%), and cerebellar vermis hypoplasia, in 2 (5.3%). Supratentorial findings included the following: thalamic fusion (26.3%), periventricular nodular heterotopias (26.3%), ventriculomegaly (26.3%), callosal abnormalities (23.7%), and hippocampal malrotations (23.7%). CONCLUSIONS: Findings seen in this large patient cohort agreed with previously published reports. Flattening of the fourth ventricle floor secondary to a bilaterally absent facial colliculus was the most frequent MR imaging finding. The presence of other brain stem and cerebellar malformations as well as supratentorial abnormalities may help explain clinical symptoms and achieve a correct diagnosis.

Histopathological reports suggest that subregions of the thalamus, which regulates multiple physiological and cognitive processes, are not uniformly affected by Alzheimer’s disease. Despite this, structural neuroimaging studies often consider the thalamus as a single region. Identification of in vivo Alzheimer’s-dependent volumetric changes in thalamic subregions may aid the characterization of early nuclei-specific neurodegeneration in Alzheimer’s disease. Here, we leveraged access to the largest single-mutation cohort of autosomal-dominant Alzheimer’s disease to test whether cross-sectional abnormalities in subregional thalamic volumes are evident in non-demented mutation carriers (n = 31), compared to non-carriers (n = 36), and whether subregional thalamic volume is associated with age, markers of brain pathology, and cognitive performance. Using automatic parcellation we examined the thalamus in six subregions (anterior, lateral, ventral, intralaminar, medial, posterior) and their relation to age and brain pathology (amyloid and tau), as measured by PET imaging. No between-group differences were observed in the volume of the thalamic subregions. In carriers, lower volume in the medial subregion was related to increased cortical amyloid and entorhinal tau burden. These findings suggest that thalamic Alzheimer’s-related volumetric reductions are not uniform even in preclinical and prodromal stages of autosomal-dominant Alzheimer’s disease and therefore, this structure should not be considered as a single, unitary structure in Alzheimer’s disease research.

To report MRI findings which reflect a pathological inflammatory condition of the uveal tract. This study includes single-center retrospective case series of five patients with clinical diagnosis of uveitis. There were 1 male (20 %) and 4 female patients (80 %). The average age was 29.6 years (range 25-38 years). Patients and 50 age-range-matched control subjects were scanned using a 1.5 T scanner. Ten additional control subjects scanned at 3 T were evaluated to have reference images at that high field. All patients (n = 5, 100 %) presented uveal tract enhancement on post-contrast T2-FLAIR fat-suppressed images and only 2 (40 %) had enhancement on T1-weighted images. The enhancement was anterior in 2 (40 %), pan-uveal in 2 (40 %), and posterior in 1 patient (20 %). Two patients (40 %) had unilateral increased vitreous signal on T2-FLAIR. One patient (20 %) had bilateral retrobulbar fat enhancement in both post-contrast T2-FLAIR and T1-weighted images. Post-contrast T2-FLAIR images can reveal abnormal enhancement of the uveal tract and retrobulbar fat as well as increased vitreous signal in patients with uveitis. In our small series, the sensitivity of post-contrast T2-FLAIR was higher than the conventional post-contrast T1-weighted images. Nonetheless, when bilateral uveal tract enhancement is present, there should be discretion before calling uveitis because the finding has been reported in different eye conditions as well as in a small percentage of healthy subjects at 1.5 T. In addition, it should be noted that post-contrast T2-FLAIR enhancement of the uveal tract is a normal finding at 3 T imaging.

A 28-year-old man presented to the emergency room complaining of right proptosis. He also manifested eye pain and facial fullness and redness in this side. Seven years ago, he had right hemifacial gunshot trauma treated with surgical reconstruction. The CT scan showed expansion of the right maxillary sinus due to a hypodense nonenhancing lesion extending to the nasal cavity, masticatory space, and extraconal space of the orbit. MRI was performed showing high signal intensity of the lesion on T2-weighted images indicating a cystic nature. T1-weighted images also demonstrated high signal intensity of the lesion suggesting hemorrhage. At endoscopic maxillary antrostomy, the diagnosis of a chronic hematic cyst was confirmed. Chronic hematic cysts of the orbit should be included in the differential diagnosis of proptosis, especially if there is clinical history of past trauma. Due to the fact that physical examination is nonspecific, radiologic evaluation is useful to confirm the diagnosis and for presurgical planning.