Retrobulbar vasculature using 7-T magnetic resonance imaging with dedicated eye surface coil.

PURPOSE: To determine the resolution and utility of using a dedicated, single-loop eye coil at 7 T to image the posterior ocular structures and vascular anatomy. METHODS: Imaging was performed on eight subjects (age range 26-54 years, four female, four male) with 7 T using a transmit head coil for excitation and a dedicated 5-cm eye surface receive coil. Acquisition parameters at 7 T for 3D spoiled gradient echo (3D-SPGR) sequences were optimized. RESULTS: It was possible to delineate the retina, sclera, and choroid, and fine details within the anterior and posterior segments of the eye. Retro-orbital and posterior ocular anatomy remained well visualized despite motion and susceptibility artifacts of anterior ocular structures. The ophthalmic arteries and their first-order branches were consistently visualized and improved with registration and summation of repeat scans. Furthermore, the central retinal vessels could be visualized. Intravenous gadolinium contrast reagent did not noticeably improve image quality. CONCLUSIONS: High-resolution 7-T MRI with a dedicated eye coil can provide unique high-resolution noninvasive images of retro-orbital and posterior ocular structural and vascular anatomy and is able to resolve structures as small as the central retina vein.

Tocotrienol vitamin E protects against preclinical canine ischemic stroke by inducing arteriogenesis.

Vitamin E consists of tocopherols and tocotrienols, in which α-tocotrienol is the most potent neuroprotective form that is also effective in protecting against stroke in rodents. As neuroprotective agents alone are insufficient to protect against stroke, we sought to test the effects of tocotrienol on the cerebrovascular circulation during ischemic stroke using a preclinical model that enables fluoroscopy-guided angiography. Mongrel canines (mean weight=26.3±3.2 kg) were supplemented with tocotrienol-enriched (TE) supplement (200 mg b.i.d, n=11) or vehicle placebo (n=9) for 10 weeks before inducing transient middle cerebral artery (MCA) occlusion. Magnetic resonance imaging was performed 1 hour and 24 hours post reperfusion to assess stroke-induced lesion volume. Tocotrienol-enriched supplementation significantly attenuated ischemic stroke-induced lesion volume (P<0.005). Furthermore, TE prevented loss of white matter fiber tract connectivity after stroke as evident by probabilistic tractography. Post hoc analysis of cerebral angiograms during MCA occlusion revealed that TE-supplemented canines had improved cerebrovascular collateral circulation to the ischemic MCA territory (P<0.05). Tocotrienol-enriched supplementation induced arteriogenic tissue inhibitor of metalloprotease 1 and subsequently attenuated the activity of matrix metalloproteinase-2. Outcomes of the current preclinical trial set the stage for a clinical trial testing the effects of TE in patients who have suffered from transient ischemic attack and are therefore at a high risk for stroke.

Minimally invasive neuroradiologic model of preclinical transient middle cerebral artery occlusion in canines.

Stroke is currently the third leading cause of death in the United States, with approximately 780,000 Americans affected by a new or recurring stroke each year. Although a variety of therapeutic approaches have shown promise in small-animal models of stroke, the vast majority of clinical trials to test the efficacy of such modalities have failed. To bridge the translational gap between laboratory and clinical research, we developed a preclinical model of acute ischemic stroke in dogs. Using a minimally invasive endovascular approach, a platinum coil was intravascularly guided through the vertebrobasilar system under C-arm fluoroscopy to occlude the M1 segment of the middle cerebral artery (MCA) for 1 h. The approach included femoral artery catheterization to access the MCA and therefore eliminated the occurrence of head trauma associated with other preclinical stroke models relying on transorbital or craniectomy approaches. After 1 h of focal MCA ischemia, the coil was retrieved to cause reperfusion, which was verified by arteriograms. At 24 h, T2-weighted coronal magnetic resonance (MR) images were acquired and processed for three-dimensional reconstruction of the brain and its vasculature. Infarction, limited to the area at risk, was noted. Two independent observers calculated the mean percentage hemispherical lesion volumes as follows: observer 1, 30.9 +/- 2.1%; observer 2, 31.2 +/- 4.3%. Infarct-affected changes in histology were determined by hematoxylin and eosin as well as by Fluoro-Jade staining. This work reports the successful development of a powerful preclinical model of stroke that lends itself to the study of biologic mechanisms as well as to testing experimental therapeutics.

Qureshi grading scheme predicts subsequent volume of brain infarction following intra-arterial thrombolysis in patients with acute anterior circulation ischemic stroke.

BACKGROUND: The importance of the site of occlusion and the presence or absence of collaterals on initial angiography in patients with acute ischemic stroke has been recognized. Qureshi recently proposed a scheme that categorizes patients with ischemic stroke based on findings observed on initial angiography. METHODS: We determined the relationship between severity of angiographic occlusion using Qureshi grading scheme and volume of brain infarction on follow-up computed tomography in 55 patients with anterior circulation ischemic stroke who underwent intra-arterial thrombolysis. RESULTS: A strong association was observed between Qureshi grades and volume of brain infarction (F ratio 6.2, P= .0005) after adjusting for patients' age, sex, National Institutes of Health Stroke Scale (NIHSS) score, thrombolytic used, and time interval between symptom onset and angiography. The relationship persisted after further adjustment for final angiographic recanalization (F ratio 5.1, P= .001). A significant relationship between initial grades and volume of brain infarction was separately observed in both patients with or without recanalization following treatment. CONCLUSIONS: Qureshi grading scheme can be effectively used to stratify patients with anterior circulation ischemic stroke undergoing intra-arterial thrombolysis using initial angiographic findings.

Use of intraoperative sodium tetradecyl sulfate for the treatment of a spinal epidural hemangioma. Technical note.

Spinal hemangiomas can be categorized into three different groups based on location. Vertebral body (VB) hemangiomas are frequent incidental findings on magnetic resonance (MR) imaging. There is a subdivision of these with spinal epidural extension that have been reported in the literature. Spinal hemangiomas can also be epidural without VB involvement; these are extremely rare with few reported cases in the thoracic epidural spinal column. The diagnosis and imaging characteristics as well as the surgical tools used in gross-total resection of spinal epidural hemangioma are not well understood. The authors present a detailed characterization of a spinal epidural hemangioma in a 30-year-old woman who presented with complaints of gradual onset of low-back pain that worsened over 1 year. The MR imaging findings indicated a large L2-S1 epidural spinal mass causing thecal sac compression. The patient underwent an L2-S1 laminectomy, and a vascular extradural mass was noted on the posterior aspect of the dura mater. Preoperative spinal angiography as well as intraoperative angiography was performed. Total resection of the tumor was achieved using intraoperative embolization with sodium tetradecyl sulfate and microscopic dissection. The postoperative MR imaging findings and clinical outcome were excellent. The findings and use of sodium tetradecyl sulfate in gross-total resection are discussed. The authors also review treatment modalities and demonstrate the utility and effectiveness of intraoperative sodium tetradecyl sulfate in grosstotal resection of large difficult spinal epidural hemangiomas.

C2/C3 pathologic fractures from polyostotic fibrous dysplasia of the cervical spine treated with percutaneous vertebroplasty.

We will discuss a potential role of percutaneous vertebroplasty (PVP) in the management of patients with severe fibrous dysplasia of the spine with multiple cervical lesions and C2-C3 pathologic fractures that may not be a good surgical candidate. Polyostotic fibrous dysplasia involvement of the cervical spine is rare. Review of literature indicates only few reported cases of surgical management with one case of mortality indicating increased risks associated with surgical intervention. While PVP is commonly used for the treatment of osteoporotic thoracolumbar vertebral compression fractures, its role in vertebral stabilization for fibrous dysplasia has not been reported. A 35-year-old man with McCune-Albright syndrome and severe polyostotic fibrous dysplasia of C2 and C3 vertebrae presented with severe neck pain, radiculopathy, quadriparesis and myelopathy. The lesion had pathologic fractures, and there was an os odontoideum with cervical cord atrophy at the C1 level. After discussing need for aggressive surgical management and potential complications, we offered PVP due to surgical risks involved. PVP was performed with a posterolateral transpedicular approach without complication. The patient had remarkable improvement in clinical relief of neck pain and improvement of myelopathic symptoms at 1-year follow-up. We present a case that illustrates a potential use of PVP in the management of a patient with symptomatic spinal fibrous dysplasia with associated pathologic fractures who was poor surgical candidate.

Clinical magnetic resonance imaging of brain tumors at ultrahigh field: a state-of-the-art review.

With the advancement of the magnetic resonance (MR) technology, the whole-body ultrahigh field MR system operated from 7 to 9.4 T becomes feasible for the routine patient imaging in clinical settings. The associated potentials and challenges from the perspectives of technology, physics, and biology as well as clinical application of the ultrahigh field MR systems are different from those systems operated at 3 T, 1.5 T, or lower field strength. In this article, we will present our initial experiences of brain tumor imaging using the 7 and 8 T whole-body MR systems at the Ohio State University Medical Center and provide a brief overview pertinent to the ultrahigh field clinical MR systems.

Intra-arterial thrombolytic therapy in peri-coronary angiography ischemic stroke.

BACKGROUND: Intra-arterial thrombolysis (IAT) for peri-coronary angiography (CA) stroke may be safe and efficacious. However, IAT may increase the risk of intracranial hemorrhage (ICH). METHODS: A retrospective study was performed involving 3 university hospitals. All peri-CA IAT-treated cases were identified. Patient demographics, stroke severity, angiographic findings, thrombolytic use, modified Rankin Scale (mRS), ICH, and mortality were determined. RESULTS: A total of 21 patients with post-left CA stroke were treated with IAT (mean age 71.8+/-12.3 years). Arterial occlusion was found in 14 (66.7%) and 7 (33.3%) of the anterior and posterior circulation, respectively. Mean time-to-therapy was 36+/-12 minutes from the time the neurological deficit was noted. mRS < or =2 occurred in 10 of 21 (48%) patients. Patients with younger age and shorter time-to-IAT had more complete arterial recanalization and clinical recovery. Symptomatic ICH occurred in 3 (14%) cases, and 4 (19%) patients died. CONCLUSIONS: Peri-CA IAT appears to be feasible and safe without increased risk of symptomatic ICH and death when compared with the previously reported IAT literature.

Clinical and imaging outcomes after stroke with normal angiograms.

BACKGROUND AND PURPOSE: Information about the prognosis of patients with acute ischemic stroke and normal angiography is limited. We report clinical and imaging outcomes of patients seen within 6 hours of symptom onset who were considered candidates for thrombolysis. METHODS: Between November 1994 and December 1999, patients with stroke onset of less than 6 hours who were thrombolytic candidates underwent cerebral angiography. Patients with normal angiograms (defined as no sign of occlusive disease in the head or neck in the symptomatic artery) were included. Admission National Institutes of Health Stroke Scale (NIHSS) scores and discharge modified Rankin scores (mRS) were obtained. CT or MR images were obtained 24 hours or longer after symptom onset. Good outcome was defined as an mRS score < or =2. For analysis, follow-up CT or MR imaging findings were classified as showing cortical infarct, subcortical infarct > or =1.5 cm, subcortical infarct < or =1.5 cm, or no new infarct. The mechanism of the normal angiogram was assumed on the basis of these results. RESULTS: Twenty-one patients with stroke had normal angiograms. About 43% (9/21) of the patients had a favorable hospital discharge clinical outcome, and an additional 33% (7/21) had favorable clinical outcomes at subsequent follow-up. New infarct on follow-up imaging was seen in 71% (15/21). Discharge mRS scores were not correlated with admission NIHSS scores or the mechanism of the normal angiogram. CONCLUSION: Approximately 76% of acute stroke patients with normal angiograms have a favorable clinical outcome, and 71% have associated new infarctions. Given these outcomes, further study is needed before recommendations regarding thrombolytic treatment can be made in this population.

Qureshi grading scheme for angiographic occlusions strongly correlates with the initial severity and in-hospital outcome of acute ischemic stroke.

BACKGROUND: The thrombolysis in myocardial infarction (TIMI) grading scheme and other classification systems have limitations in evaluating patients with ischemic stroke because they do not account for occlusion location or collateral circulation. The Qureshi grading scheme has been recently proposed to evaluate the severity of arterial occlusion in acute ischemic stroke because of limitations in existing grading systems. METHODS: The Qureshi grading scheme assigns a score from 0 to 5 on the basis of occlusion site and collateral supply. The authors determined the relationship between initial severity of stroke and outcome at discharge measured by the National Institutes of Health Stroke Scale (NIHSS) and the Qureshi grading scale assessed from initial angiography (by a neuroradiologist blinded to the clinical examination) in 57 patients who underwent intra-arterial therapy for acute ischemic stroke within 6 hours of symptom onset. RESULTS: A strong association was observed between the initial severity of neurological deficits and Qureshi scheme on angiography (F ratio = 2.6, P =.03). The initial NIHSS for grade 1 was 11 +/- 4 and progressively increased to 23 +/- 6 for grade 5. In the multivariate analysis, initial NIHSS was significantly associated with Qureshi scheme on angiography (R2 = 358, P =.03). The mean discharge NIHSS was 12 +/- 10 (range, 0-40). There was also a direct relationship between the Qureshi scheme and discharge NIHSS (F ratio = 2.8, P =.02). CONCLUSION: The Qureshi grading scheme can be effectively used to determine the severity of ischemic stroke (brain at risk) from the initial angiography.

Real-time CT-guided spinal biopsy with a disposable stereotactic device: a technical note.

We compared eight spinal needle biopsy procedures performed with an investigational disposable real-time stereotactic device and eight spinal needle freehand biopsies in which a standard technique was used, to determine whether the investigational device added value to the procedure. The device uses a simple stereotactic diaphragm pattern to define two vector points. The procedures in which the device was used were completed in 38% less time, using 50% fewer images, with considerably improved spatial accuracy and increased operator confidence, despite the device learning curve.