Spontaneous Intracranial Hypotension: Atypical Radiologic Appearances, Imaging Mimickers, and Clinical Look-Alikes.

Spontaneous intracranial hypotension is a condition characterized by low CSF volume secondary to leakage through a dural defect with no identifiable cause. Patients classically present with orthostatic headaches, but this symptom is not specific to spontaneous intracranial hypotension, and initial misdiagnosis is common. The most prominent features of spontaneous intracranial hypotension on intracranial MR imaging include "brain sag" and diffuse pachymeningeal enhancement, but these characteristics can be seen in several other conditions. Understanding the clinical and imaging features of spontaneous intracranial hypotension and its mimickers will lead to more prompt and accurate diagnoses. Here we discuss conditions that mimic the radiologic and clinical presentation of spontaneous intracranial hypotension as well as other disorders that CSF leaks can imitate.

Dentate Update: Imaging Features of Entities That Affect the Dentate Nucleus.

The dentate nucleus is a cerebellar structure involved in voluntary motor function and cognition. There are relatively few entities that affect the dentate, and the clinical features of these conditions are often complex and nonspecific. Because these entities are rarely encountered, the formulation of a differential diagnosis can be difficult. Many of the conditions are reversible or treatable with early intervention. Therefore, it is important to recognize classic clinical presentations and their associated characteristic imaging findings. We provide a summary of entities that affect the dentate nucleus and a diagnostic workflow for approaching dentate nucleus imaging abnormalities.

Intracranial and Extracranial Neurovascular Manifestations of Takayasu Arteritis.

BACKGROUND AND PURPOSE: Takayasu arteritis is a rare, large-vessel vasculitis that presents with symptoms related to end-organ ischemia. While the extracranial neurovascular manifestations of Takayasu arteritis are well-established, little is known regarding the intracranial manifestations. In this study, we characterize the intracranial and cervical neurovascular radiologic findings in patients with Takayasu arteritis. MATERIALS AND METHODS: Patients with Takayasu arteritis who presented to our institution between 2001 and 2016 with intracranial and/or cervical vascular imaging were included in this study. Images were evaluated for the presence of vascular abnormalities, including intracranial or extracranial stenosis, vessel-wall thickening, dissection, subclavian steal, aneurysms, infarcts, and hemorrhages. Descriptive analyses are reported. RESULTS: Seventy-nine patients with Takayasu arteritis met the criteria for inclusion in this study. The most common presenting neurologic symptoms were headache (32.9%) and dizziness (15.2%). Intracranial and extracranial vascular imaging was performed in 84.8% and 89.9% of patients, respectively. Among patients with intracranial vascular imaging, 3 (3.9%) had intracranial aneurysms, 3 (3.9%) had acute large-vessel occlusion, 6 (7.6%) had intracranial vasculitis, and 1 (1.3%) had reversible cerebrovascular constriction syndrome. Among patients with cervical vascular imaging, 42 (53.1%) had some degree of narrowing of the common carotid artery and 18 (22.8%) had narrowing of the ICAs. Seventeen patients (23.6%) had subclavian steal. CONCLUSIONS: Intracranial vascular abnormalities in patients with Takayasu arteritis presenting with neurologic symptoms are not rare, with cerebral vasculitis seen in 7.8% of patients, and stroke secondary to large-vessel occlusion, in 3.9% of patients. Cervical vascular manifestations of Takayasu arteritis were present in most patients in our study.

Diffusion-Weighted Imaging-Detected Ischemic Lesions following Endovascular Treatment of Cerebral Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms is associated with the risk of thromboembolic ischemic complications. Many of these events are asymptomatic and identified only on diffusion-weighted imaging. We performed a systematic review and meta-analysis to study the incidence of DWI positive for thromboembolic events following endovascular treatment of intracranial aneurysms. MATERIALS AND METHODS: A comprehensive literature search identified studies published between 2000 and April 2016 that reported postprocedural DWI findings in patients undergoing endovascular treatment of intracranial aneurysms. The primary outcome was the incidence of DWI positive for thromboembolic events. We examined outcomes by treatment type, sex, and aneurysm characteristics. Meta-analyses were performed by using a random-effects model. RESULTS: Twenty-two studies with 2148 patients and 2268 aneurysms were included. The overall incidence of DWI positive for thromboembolic events following endovascular treatment was 49% (95% CI, 42%-56%). Treatment with flow diversion trended toward a higher rate of DWI positive for lesions than coiling alone (67%; 95% CI, 46%-85%; versus 45%; 95% CI, 33%-56%; P = .07). There was no difference between patients treated with coiling alone and those treated with balloon-assisted (44%; 95% CI, 29%-60%; P = .99) or stent-assisted (43%; 95% CI, 24%-63%; P = .89) coiling. Sex, aneurysm rupture status, location, and size were not associated with the rate of DWI positive for lesions. CONCLUSIONS: One in 2 patients may have infarcts on DWI following endovascular treatment of intracranial aneurysms. There is a trend toward a higher incidence of DWI-positive lesions following treatment with flow diversion compared with coiling. Patient demographics and aneurysm characteristics were not associated with DWI-positive thromboembolic events.

LMP-420: a novel purine nucleoside analog with potent cytotoxic effects for CLL cells and minimal toxicity for normal hematopoietic cells.

B-cell chronic lymphocytic leukemia (CLL) is characterized by slow accumulation of malignant cells, which are supported in the microenvironment by cell-cell interactions and soluble cytokines such as tumor necrosis factor (TNF). We evaluated the effect of the small molecule TNF inhibitor LMP-420 on primary CLL cells. The mean concentration of LMP-420 required to induce 50% cytotoxicity (ED50) at 72 h was 245 n. LMP-420-induced time- and dose-dependent apoptosis, as shown by annexin V staining, caspase activation and DNA fragmentation. These changes were associated with decreased expression of anti-apoptotic proteins Mcl-1, Bcl-xL and Bcl-2. CLL cells from patients with poor prognostic indicators showed LMP-420 sensitivity equal to that for cells from patients with favorable characteristics. In addition, LMP-420 potentiated the cytotoxic effect of fludarabine and inhibited in vitro proliferation of stimulated CLL cells. Gene expression profiling indicated that the mechanism of action of LMP-420 may involve suppression of nuclear factor-kappaB and immune response pathways in CLL cells. LMP-420 had minimal effects on normal peripheral blood mononuclear cell, B- and T-cell function, and hematopoietic colony formation. Our data suggest that LMP-420 may be a useful treatment for CLL with negligible hematologic toxicities.