Clinical role of abbreviated and ultrafast mri in breast imaging.

Current breast cancer screening relies on mammography, digital breast tomosynthesis and breast ultrasound. In select populations, breast MRI is also of great utility. However, multiple factors limit widespread use of breast MRI for screening. Efforts have been made to increase the availability of breast MRI for screening, in large part due to the increased cancer detection rate of breast MRI compared to mammography. Techniques include shortening standard breast MRI protocols with the potential for accommodating MRI screening in a higher number of patients. This review will explain the role of abbreviated breast MRI and ultrafast breast MRI in breast imaging, and detail how these approaches differ from standard dynamic contrast-enhanced breast MRI. In addition, limitations and advantages of these techniques will also be discussed.

Arachnoid Granulation Causing Unilateral Pulsatile Tinnitus Treated With Dural Venous Sinus Stenting.

BACKGROUND: Large arachnoid granulations that protrude into dural venous sinuses and partially obstruct outflow are an underappreciated etiology of pulsatile tinnitus (PT). Endovascular dural venous sinus stenting is thought to diminish turbulent venous outflow and may relieve obstruction caused by arachnoid granulations. METHODS: Four patients at two institutions were evaluated for unilateral PT. Magnetic resonance imaging and digital subtraction angiography revealed moderate-to-severe stenoses from large arachnoid granulations within the implicated transverse sinus. All patients underwent venous manometry and endovascular sinus stenting. RESULTS: All patients experienced immediate and complete remission of their PT. Stenoses were relieved by a mean of 93% by Warfarin-Aspirin Symptomatic Intracranial Disease criteria. There were no procedural or periprocedural complications. All patients continued to report complete symptom resolution at a mean of 8-month follow-up. CONCLUSIONS: PT from arachnoid granulations are an underappreciated pathomechanism. Endovascular dural venous sinus stenting is an effective intervention for treating unilateral PT secondary to large arachnoid granulation.

Immunomodulation with Human Umbilical Cord Blood Stem Cells Ameliorates Ischemic Brain Injury - A Brain Transcriptome Profiling Analysis.

Our group previously demonstrated that administration of a CD34-negative fraction of human non- hematopoietic umbilical cord blood stem cells (UCBSC) 48 h after ischemic injury could reduce infarct volume by 50% as well as significantly ameliorate neurological deficits. In the present study, we explored possible mechanisms of action using next generation RNA sequencing to analyze the brain transcriptome profiles in rats with ischemic brain injury following UCBSC therapy. Two days after ischemic injury, rats were treated with UCBSC. Five days after administration, total brain mRNA was then extracted for RNAseq analysis using Illumina Hiseq 2000. We found 275 genes that were significantly differentially expressed after ischemic injury compared with control brains. Following UCBSC treatment, 220 of the 275 differentially expressed genes returned to normal levels. Detailed analysis of these altered transcripts revealed that the vast majority were associated with activation of the immune system following cerebral ischemia which were normalized following UCBSC therapy. Major alterations in gene expression profiles after ischemia include blood-brain-barrier breakdown, cytokine production, and immune cell infiltration. These results suggest that UCBSC protect the brain following ischemic injury by down regulating the aberrant activation of innate and adaptive immune responses.

Development of a Novel Canine Model of Ischemic Stroke: Skull Base Approach with Transient Middle Cerebral Artery Occlusion.

OBJECTIVE: Although canine stroke models have several intrinsic advantages, establishing consistent and reproducible territorial stroke in these models has been challenging because of the abundance of collateral circulation. We have described a skull-base surgical approach that yields reproducible stroke volumes. METHODS: Ten male beagles were studied. In all 10 dogs, a craniectomy was performed to expose the circle of Willis. Cerebral aneurysm clips were temporarily applied to the middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery, and/or ophthalmic artery (OA) for 1 hour, followed by cauterization of the distal MCA pial collateral vessels. Indocyanine green angiography was performed to assess the local blood flow to the intended area of infarction. The dogs' neurologic examination was evaluated, and the stroke burden was quantified using magnetic resonance imaging. RESULTS: High mortality was observed after 1-hour clip occlusion of the posterior cerebral artery, MCA, ACA, and OA (n = 4). Without coagulation of the MCA collateral vessels, 1-hour occlusion of the MCA and/or ACA and OA yielded inconsistent stroke volumes (n = 2). In contrast, after coagulation of the distal MCA pial collateral vessels, 1-hour occlusion of the MCA, ACA, and OA yielded consistent territorial stroke volumes (n = 4; average stroke volume, 9.13 ± 0.90 cm3; no surgical mortalities), with reproducible neurologic deficits. CONCLUSION: Consistent stroke volumes can be achieved in male beagles using a skull base surgical approach with temporary occlusion of the MCA, ACA, and OA when combined with cauterization of the distal MCA pial collateral vessels.

Amelioration of Ischemic Brain Injury in Rats With Human Umbilical Cord Blood Stem Cells: Mechanisms of Action.

Despite the high prevalence and devastating outcome, there remain a few options for treatment of ischemic stroke. Currently available treatments are limited by a short time window for treatment and marginal efficacy when used. We have tested a human umbilical cord blood-derived stem cell line that has been shown to result in a significant reduction in stroke infarct volume as well as improved functional recovery following stroke in the rat. In the present study we address the mechanism of action and compared the therapeutic efficacy of high- versus low-passage nonhematopoietic umbilical cord blood stem cells (nh-UCBSCs). Using the middle cerebral arterial occlusion (MCAo) model of stroke in Sprague-Dawley rats, we administered nh-UCBSC by intravenous (IV) injection 2 days following stroke induction. These human cells were injected into rats without any immune suppression, and no adverse reactions were detected. Both behavioral and histological analyses have shown that the administration of these cells reduces the infarct volume by 50% as well as improves the functional outcome of these rats following stroke for both high- and low-passaged nh-UCBSCs. Flow cytometry analysis of immune cells present in the brains of normal rats, rats with ischemic brain injury, and ischemic animals with nh-UCBSC treatment confirmed infiltration of macrophages and T cells consequent to ischemia and reduction to normal levels with nh-UCBSC treatment. Flow cytometry also revealed a restoration of normal levels of microglia in the brain following treatment. These data suggest that nh-UCBSCs may act by inhibiting immune cell migration into the brain from the periphery and possibly by inhibition of immune cell activation within the brain. nh-UCBSCs exhibit great potential for treatment of stroke, including the fact that they are associated with an increased therapeutic time window, no known ill-effects, and that they can be expanded to high numbers for, and stored for, treatment.