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.

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 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.