Nancy Nealon

Reduction of PK11195 uptake observed in multiple sclerosis lesions after natalizumab initiation

OBJECTIVE The objective of this study is to longitudinally analyze the uptake of [11C]PK11195-PET in multiple sclerosis patients after 3 and 6 months of natalizumab treatment. METHODS Eighteen MS patients, starting treatment with monocloncal anti-VLA-4, were enrolled in a longitudinal PK-PET study. PK uptake was quantified by volume of distribution (VT) calculation using image-derived input function at baseline, 3 and 6 months. Pharmacokinetic quantification was done using a segmented MRI, and selected areas included white matter, gadolinium enhancing lesions, non-enhancing lesions, cortical grey matter and thalamus. VTs of lesions were calculated in reference to each patients white matter (VT ratio=VTr), to consider physiologic variability. RESULTS Test-retest variability was stable for healthy control (HC). Quantification of PK uptake was completed in 18 patients, and baseline uptake was compared to 6-month uptake. After the start of natalizumab VTr significantly decreased in 13 individual enhancing lesions present within 5 patients (p=0.001). Moreover, VTr of the sum of non-enhancing lesions showed a moderate decrease (p=0.03). No longitudinal changes were detected in normal appearing white matter, the thalamus and cortical grey matter. CONCLUSION A reduction in PK11195 uptake was observed in both enhancing and chronic lesions after the start of natalizumab. PK11195 PET can be used as tool to assess the longitudinal change in MS lesions.

Differential Impact of Multiple Sclerosis on Cortical and Deep Gray Matter Structures in African Americans and Caucasian Americans.

African Americans with multiple sclerosis (AAwMS) have different disease phenotypes when compared to Caucasians Americans with MS (CAwMS). The pathologic basis of this difference in disease presentation is unknown.

Progressive outer retinal necrosis in a multiple sclerosis patient on natalizumab

A 54-year-old woman with multiple sclerosis, on natalizumab, reported 2 weeks of left eye redness and blurry vision, previously diagnosed as conjunctivitis. Visual acuity was 20/125. Funduscopy revealed progressive outer retinal necrosis (figure 1), a viral retinitis of immunocompromised patients that frequently causes vision loss.1 Sequential bilateral involvement is common. Etiologies include varicella zoster, herpes simplex, and rarely cytomegalovirus; aqueous PCR revealed varicella. Natalizumab was held. IV and intravitreal antivirals were administered. After repair of retinitis-induced retinal detachment and resolution of retinitis, visual acuity was 20/125 (figure 2). In immunocompromised patients with ocular symptoms, clinicians should consider infectious retinitis and obtain prompt funduscopic evaluation.

An Acute Disseminated Encephalomyelitis‐Like Illness in the Elderly: Neuroimaging and Neuropathology Findings

Acute disseminated encephalomyelitis (ADEM) is a rare demyelinating disease of the central nervous system (CNS) that classically occurs in children and adolescents. It characteristically presents with acute inflammation, resulting in demyelination, often following an infectious disease. ADEM has been described in adult patients, but the incidence in the adult and especially elderly population is low.