Analysis of ischemic cerebral lesions using 3.0-T diffusion-weighted imaging and magnetic resonance angiography after revascularization surgery for ischemic disease

Background

Cerebral revascularization surgery (CRS) is increasingly recognized as an important component in the treatment of complex cerebral vascular disease and tumors. CRS requires that the incidence of perioperative neurological complications should be minimized, because CRS for ischemic disease is often not the goal of treatment, but rather a prophylactic surgery. CRS carries the risk of focal postoperative neurological deficits. Little has been established concerning mechanisms of post-CRS ischemia. We used 3.0-T diffusion-weighted magnetic resonance imaging (DWI) and magnetic resonance angiography (MRA) to analyze the incidence and mechanism of ischemic lesions.

Methods

We studied the anterior circulation territory after 20 CRS procedures involving 33 vascular anastomosis procedures (13 double anastomoses and 7 single anastomoses) in 12 men and 8 women between June 2007 and October 2011. The operations included single or double superficial temporal artery–middle cerebral artery (STA–MCA) anastomosis to treat internal carotid artery/MCA occlusions or severe MCA stenosis. A combined STA–MCA anastomosis and indirect bypass were performed for moyamoya disease. Postoperative DWI and MRA were obtained in all patients between 24 and 96 h after surgery to detect thromboembolism, hypoperfusion, or procedural ischemic complications and vasospasms of the donor STA.

Results

Follow-up DWI and MRA were carried out 1.8 ± 0.6 days after CRS (range, 1–4 days). Temporary occlusion time for anastomoses averaged 18.9 min (range, 16–32 min). Asymptomatic new hyperintensities occurred in the ipsilateral hemisphere of 2 patients on postoperative DWI (10% patients/6.0% anastomoses), and 1 moyamoya patient (5.0% patients/3.0% anastomoses) developed a symptomatic hyperintensity in the ipsilateral occipital lobe in response to the operation. Two abnormal small (<5 mm) cortical DWI lesions were caused by sacrifices of a small branch of the recipient MCA.

Conclusion

This study is the first postoperative 3.0-T DWI study of CRS and related clinical events. The incidence of symptomatic postoperative DWI abnormalities was restricted to 1 moyamoya patient representing 5.0% of total patients and 3.0% anastomoses. Although some postoperative DWI abnormalities occurred, CRS was found to be safe with a low risk of symptomatic ischemia.     

Perioperative complications of superficial temporal artery to middle cerebral artery bypass for the treatment of complex middle cerebral artery aneurysms

Object

Only a few studies have reported the risk of ischemic complications occurring when superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis is performed during surgery for complex MCA aneurysms.

Subjects and methods

This is a retrospective study of 10 patients (age 52–73) with MCA aneurysms treated with revascularization surgery. The aneurysms were 10–50 mm in size (mean: 21 mm). We studied the causes and frequency of ischemic complications by analyzing postoperative magnetic resonance imaging.

Results

Postoperative diffusion-imaging confirmed ischemic complications in six of the 10 patients (in two of the five ruptured aneurysms and in four of the five unruptured). The ischemic complications that observed were infarction of the lenticulostriate artery territory in three cases, cortical infarction in two cases, and cerebral infarction that was likely to be due to cerebral vasospasm in one case. In one case, both cortical infarction and infarction of the lenticulostriate artery territory were observed. The Glasgow Outcome Scale (GOS) scores at the time of discharge indicated good recovery (GR) and moderate disability (MD) in seven cases, severe disability (SD) in two cases, and death (D) in one case.

Conclusions

The present study suggests the possibility that STA–MCA anastamosis in surgeries for MCA aneurysms can be performed with comparatively better safety. However, the temporary occlusion time with this surgery is longer than that with a temporary clipping for aneurysmal surgery; thus, we believe that adequate countermeasures are required to prevent ischemic complications.     

The angiographic and clinical outcomes of intracranial aneurysms following irradiation in patients with nasopharyngeal carcinoma: A 13-year experience and literature review

Background and purpose

Intracranial aneurysms are a known but rare complication of radiotherapy (RT). We reviewed the angiographic and clinical outcomes of intracranial aneurysms following RT in patients with nasopharyngeal carcinoma (NPC), a malignancy endemic in Hong Kong.

Combined diffusion- and perfusion-weighted imaging: a new way for the assessment of hemispheric transient ischemic attack patients

Abnormalities in diffusion-weighted and perfusion-weighted magnetic resonance images not only occur in stroke patients but also in transient ischemic attack patients. We found magnetic resonance images were abnormal in 28 patients (68%): 15 had diffusion-weighted imaging abnormalities, 7 had both diffusion-weighted imaging and perfusion-weighted imaging defects and 6 had an isolated perfusion-weighted imaging abnormality. Patients with shorter onset to magnetic resonance imaging, large artery atherothrombosis, coronary artery disease, hyperlipidemia and hemiparesis were more likely to show perfusion-weighted imaging abnormalities. Compared with patients who had a good prognosis, in poor prognosis patients, the relative cerebral blood flow and relative cerebral blood volume was significantly higher. The data suggest that transient ischemic attack patients are more likely to have a poor prognosis when white matter of the symptomatic side shows hyperperfusion within 24 h of symptom onset; however, patients are more likely to have a good prognosis when white matter of the symptomatic side shows hypoperfusion.     

Plasma Levels of miR-125b-5p and miR-206 in Acute Ischemic Stroke Patients After Recanalization Treatment: A Prospective Observational Study

Introduction: Multiple microRNAs (miRNAs) participate in the response to hypoxic/ischemic and ischemia-reperfusion events. However, the expression of these miRNAs in circulation from patients with acute ischemic stroke (AIS) receiving recanalization treatment has not been examined, and whether they are associated with the severity and outcome of stroke is still unknown. Materials and methods: In this prospective cohort study, plasma levels of miR-125b-5p, miR-15a-3p, miR-15a-5p, and miR-206 were measured at 24 hours after thrombolysis with or without endovascular treatment in 94 patients with AIS, as determined by qRT-PCR. Stroke severity was assessed based on National Institutes of Health Stroke Scale (NIHSS) score and infarct lesion. Intracranial haemorrhage (ICH) was recorded. An unfavorable outcome was defined as a modified Rankin Scale score greater than 2 at day 90 after stroke. Results: miR-125b-5p and miR-206 levels were correlated with NIHSS scores (P = .014 and P = .002) and cerebral infarction volumes (P = .025 and P = .030). miR-125b-5p levels were significantly higher in patients with an unfavorable outcome than in patients with a favorable outcome (P = .002) and showed good diagnostic accuracy in discriminating the presence of an unfavorable outcome (area under the curve .735, 95% confidence interval .623-.829, P < .001). No association was found between different miRNAs and ICH. Conclusions: In AIS patients after thrombolysis with or without endovascular treatment, miR-125b-5p is a novel prognostic biomarker highly associated with an unfavorable outcome. miR-125b-5p and miR-206 levels are associated with stroke severity.