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ABSTRACT: It is common that physicians are faced with patients who have severe steno-occlusion of intracranial arteries in the absence of clinical symptoms. This study is to determine whether a 7T magnetic resonance angiogram (MRA) could provide the improved depiction of microvessels of asymptomatic patients with steno-occlusive middle cerebral artery (MCA) and possible clues for diagnosis of their clinical symptoms. All the patients who were identified as severe MCA steno-occlusions underwent a 7T MRA study. Three of these also underwent conventional angiography (TFCA). The vascular densities around the steno-occlusive MCA and posterior cerebral artery (PCA) branches as control vessels were measured and the difference between the median values of 7T and 3T MRA data was also analyzed. The results of 7T MRA revealed numerous microvessels not visible by conventional MRA. These 7T MRA images were also comparable to those obtained by an invasive conventional angiography (TFCA). The median values of vascular densities observed by 7T MRA were significantly higher than those by 3T MRA (5.28 at 7T vs. 1.45 at 3T for steno-occlusive MCA, p = 0.012, while 3.39 at 7T vs. 3.32 at 3T for normal PCA, p = 0.093). Ultra-high-field 7T MRA is a totally noninvasive angiographic technique that is capable of visualizing microvascular circulation that is usually difficult with conventional MRA. This visualization technique, therefore, could provide an important avenue on the diagnosis of steno-occlusion as well as the search of the roles of the microvessel, especially collaterals, in the preservation of normal blood circulation in patients with asymptomatic MCA steno-occlusion.
Journal of Neurology 07/2012; · 3.47 Impact Factor
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ABSTRACT: To perform a comparative study between two groups of populations, titanium (T) group versus stainless steel (S) group, who were clipped with titanium and stainless steel materials, respectively, the incidence of regrowth from the original aneurysms, the clip slippage, and post-clipping seizure attack were analyzed. The patients were followed more than 5 years after microsurgical cerebral aneurysms clipping.
Data from 1986 through 2008 were extensively reviewed on a consecutive series of 3,770 patients who referred for ruptured/unruptured cerebral aneurysms. Forty-seven patients in the S group and 48 in the T group who met inclusion criteria, were selected for this study.
The incidence of regrowth were noted that two out of total 47 patients (4.3%) in the S group, and none in the T group. The clip slippage was not observed in both groups. And there was no statistical difference (p = 0.242) in terms of regrowth between two groups. Seven out of 47 cases (14.9%) developed post-clipping seizure in the S group. On the other hand, two (4.2%) of 48 patients presented the symptom in the T group. Also, there was no significant difference (p = 0.091) between two groups.
The metallic types of clip employed for the microsurgical cerebral aneurysm clipping does not have any significant clinical outcome differences in this study.
Journal of cerebrovascular and endovascular neurosurgery. 06/2012; 14(2):79-83.
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ABSTRACT: Background Small vessel diseases have been studied noninvasively with magnetic resonance imaging. Direct observation or visualization of the connected microvessel to the infarct, however, was not possible due to the limited resolution. Hence, one could not determine whether vessel occlusion or abnormal narrowing is the cause of an infarct.Methods In this report, we demonstrate that the small vessel related to the infarct can be detected using ultra-high-field (7 T) magnetic resonance imaging and a three dimensional image analysis and modeling technique for microvessels, which thereby enables us to quantify the vessel morphology directly, that is, visualize the vessel that is related to the infarct. We compared vessels of selected stroke patients, who had recovered from stroke, with vessels from typical stroke patients, who had after effects like motor weakness, and age-matched healthy subjects to demonstrate the potential of the technique.Results The experimental results show that typical stroke patients had overall degradation or loss of small vessels, compared with the selected patients as well as healthy subjects. The selected patients, however, had only minimal loss of vessels, except for one vessel located close to the infarct area.Conclusions These preliminary results demonstrated that 7 T magnetic resonance imaging together with a three dimensional image analysis and modeling technique could provide information for detection of the vessel related to the infarct. In addition, three dimensional image analysis and modeling of vessels could further provide quantitative information on the microvessel structures comprising diameter, length and tortuosity.
International Journal of Stroke 10/2011; · 2.38 Impact Factor
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ABSTRACT: Noninvasive magnetic resonance angiography using ultra-high-field magnetic resonance imaging has recently provided us with the potential to image cerebral microvascular structures such as the lenticulostriate arteries. However, most studies using ultra-high-field magnetic resonance angiography have been limited to the visualisation of microvessels in healthy subjects, and the direct comparison of patients with microvascular disease has not been reported.
The aim of this study was to investigate the lenticulostriate arteries of patients with lacunar strokes of the basal ganglia and surrounding areas using 7 T magnetic resonance angiography.
Ten stroke patients who had infarctions in the basal ganglia and adjacent areas detected using T2(*)-weighted images obtained from a conventional 1·5 T magnetic resonance imaging and 10 age-matched healthy subjects were recruited for this study. The large main vessels in the patient group were inspected to identify abnormalities such as stenosis. The characteristics of the lenticulostriate arteries visualised by 7 T magnetic resonance angiography, such as the number of branches and stems, curvature and tortuosity were analysed and compared between the patient and the control groups.
All patients had infarctions in the basal ganglia and adjacent regions, which were clearly determined by T2(*)-weighted images. However, there was no evidence of large-vessel abnormalities in the patient group. Analysis of 7 T magnetic resonance angiography data revealed that the overall number of lenticulostriate arteries branches in the patient group was significantly less than the control group (P=0·003). However, no statistical difference in the number of stems, curvature and tortuosity between the two groups was found (P=0·396, 0·258 and 0·888, respectively).
This study demonstrates that noninvasive magnetic resonance angiography using 7 T magnetic resonance imaging can visualise abnormalities in the cerebral microvasculature of stroke patients, and that the number of lenticulostriate arteries supplying the region of the basal ganglia is less in these patients compared with age-matched controls.
International Journal of Stroke 10/2010; 5(5):374-80. · 2.38 Impact Factor
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ABSTRACT: To visualize the perforating arteries originating from basilar artery (BA) by using ultra-high resolution 7T MR angiography (MRA) and optimizing MR parameters as well as radio frequency (RF) coils, which may provide important information for neurosurgery and understanding diseases of the pons, but was unable to clearly visualize with conventional MRA techniques.
Seven healthy volunteers (five males and two females, age [mean +/- SD] = 28.71 +/- 7.54 years) were scanned using optimized MR parameters to obtain images of pontine arteries (PAs) originating from the main trunk of BA. Two different volume coils and a phased array coil were designed and compared for this study. The images obtained at 7T MRA were compared with those at 1.5T and 3T MRA.
The results showed that PA imaging at 7T MRI consistently provided clearly identifiable vessels, which were difficult to visualize in MR angiograms obtained at 1.5T and 3T MRIs. Volume RF coils had higher sensitivity for the center of the brain, which enhanced PA imaging compared to phased array coil. The average number of PA branches in all seven subjects observable by 7T MRA was 7.14 +/- 2.79, and the visualized PA branches were found to mainly propagating on the surface of the pons.
We have demonstrated that ultra-high resolution 7T MRA could delineate the PAs using optimized imaging parameters and volume RF coils compared to commercially available 1.5T and 3T MRIs.
Journal of Magnetic Resonance Imaging 09/2010; 32(3):544-50. · 2.70 Impact Factor
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ABSTRACT: Trochlear nerve palsy associated with spontaneous subarachnoid hemorrhage (SAH) is known to be a rare malady. We report here on a patient who suffered with left trochlear nerve palsy following rupture of a right posterior communicating artery aneurysm. A 56-year-woman visited our emergency department with stuporous mental change. Her Hunt-and-Hess grade was 3 and the Fisher grade was 4. Cerebral angiography revealed a ruptured aneurysm of the right posterior communicating artery. The aneurysm was clipped via a right pterional approach on the day of admission. The patient complained of diplopia when she gazed to the left side, and the ophthalmologist found limited left inferolateral side gazing due to left superior oblique muscle palsy on day 3. Elevated intracranial pressure, intraventricular hemorrhage or a dense clot in the basal cisterns might have caused this trochlear nerve palsy.
Journal of Korean Neurosurgical Society 05/2010; 47(5):392-4. · 0.60 Impact Factor
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ABSTRACT: Hypertension, a major risk factor for stroke, is associated with altered arterial anatomy and function; however, the limited resolution of current imaging techniques has restricted the in vivo study of microvascular changes in the brain. In this report, we quantitatively examined the lenticulostriate arteries in hypertensive patients using ultrahigh-field 7T MRI. We compared the number of stems and branches, curvature, and tortuosity of the lenticulostriate arteries by 3D time-of-flight magnetic resonance angiography among 20 hypertensive patients (mean age: 46.6+/-9.1 years) and 20 age-matched healthy subjects (mean age: 47.7+/-8.1 years). The average numbers of stems and branches in hypertensive patients were significantly less than those of healthy subjects (P<0.002). However, this difference was abolished in older volunteers (>45 years old), whereas the difference between young hypertensive patients (< or = 45 years old) and age-matched healthy controls was augmented by 55% for stems and 91% for branches (P=0.001). In comparison, there were no differences in the average curvature and tortuosity of the lenticulostriate arteries and no significant difference when corrected for smoking (P=0.064). In conclusion, our results showed that there was a substantial difference in the lenticulostriate arteries of hypertensive patients compared with healthy individuals when observed in vivo by ultrahigh-resolution 7T magnetic resonance angiography, and the difference was considerable in young subjects.
Hypertension 10/2009; 54(5):1050-6. · 6.21 Impact Factor
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ABSTRACT: Chronic subdural hematoma (CSDH) is one of the most common types of traumatic intracranial hemorrhage, usually occurring in the older patients, with a good surgical prognosis. Burr hole craniostomy is the most frequently used neurosurgical treatment of CSDH. However, there have been only few studies to assess the role of the number of burr holes in respect to recurrence rates. The aim of this study is to compare the postoperative recurrence rates between one and two burr craniostomy with closed-system drainage for CSDH.
From January 2002 to December 2006, 180 consecutive patients who were treated with burr hole craniostomy with closed-system drainage for the symptomatic CSDH were enrolled. Pre- and post-operative computed tomography (CT) scans and/or magnetic resonance imaging (MRI) were used for radiological evaluation. The number of burr hole was decided by neurosurgeon's preference and was usually made on the maximum width of hematoma. The patients were followed with clinical symptoms or signs and CT scans. All the drainage catheters were maintained below the head level and removed after CT scans showing satisfactory evacuation. All patients were followed-up for at least 1 month after discharge.
Out of 180 patients, 51 patients were treated with one burr hole, whereas 129 were treated with two burr holes. The overall postoperative recurrence rate was 5.6% (n = 10/180) in our study. One of 51 patients (2.0%) operated on with one burr hole recurred, whereas 9 of 129 patients (7.0%) evacuated by two burr holes recurred. Although the number of burr hole in this study is not statistically associated with postoperative recurrence rate (p > 0.05), CSDH treated with two burr holes showed somewhat higher recurrence rates.
In agreement with previous studies, burr hole craniostomy with closed drainage achieved a good surgical prognosis as a treatment of CSDH in this study. Results of our study indicate that burr hole craniostomy with one burr hole would be sufficient to evacuate CSDH with lower recurrence rate.
Journal of Korean Neurosurgical Society 08/2009; 46(2):87-92. · 0.60 Impact Factor
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ABSTRACT: The purpose of this study was to analyze human lenticulostriate arteries (LSAs) obtained non-invasively by 7.0-T MRI. A three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) technique was used with an investigational 7.0-T MRI scanner with a radio-frequency coil that was optimized and designed for angiographic purposes. We obtained images from 16 healthy volunteers (8 males and 8 females, mean age 21 +/- 2.7 years). For direct comparison of LSA images with digital subtraction angiography (DSA), we also obtained 7.0-T MRA and DSA images from one patient, a 27-year-old woman with a posterior fossa arteriovenous malformation (AVM). We then analyzed the characteristics of LSAs using a custom data analysis method with MatLab for quantitative analysis. Analysis of LSA images included shape and number of branches and origins, findings that are essential and useful for quantification of LSA abnormalities in both healthy controls and patients. Ultra-high-field MRA provided clear anatomic delineation of the LSAs, thereby suggesting that 7.0-T MRA may be a promising technique for microvascular imaging of the LSAs.
Magnetic Resonance in Medicine 01/2009; 61(1):136-44. · 2.96 Impact Factor
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ABSTRACT: The purpose of this study was to analyze human lenticulostriate arteries (LSAs) obtained non-invasively by 7.0-T MRI. A three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) technique was used with an investigational 7.0-T MRI scanner with a radio-frequency coil that was optimized and designed for angiographic purposes. We obtained images from 16 healthy volunteers (8 males and 8 females, mean age 21 ± 2.7 years). For direct comparison of LSA images with digital subtraction angiography (DSA), we also obtained 7.0-T MRA and DSA images from one patient, a 27-year-old woman with a posterior fossa arteriovenous malformation (AVM). We then analyzed the characteristics of LSAs using a custom data analysis method with MatLab for quantitative analysis. Analysis of LSA images included shape and number of branches and origins, findings that are essential and useful for quantification of LSA abnormalities in both healthy controls and patients. Ultra–high-field MRA provided clear anatomic delineation of the LSAs, thereby suggesting that 7.0-T MRA may be a promising technique for microvascular imaging of the LSAs. Magn Reson Med 61:136–144, 2009. © 2008 Wiley-Liss, Inc.
Magnetic Resonance in Medicine 12/2008; 61(1):136 - 144. · 2.96 Impact Factor
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ABSTRACT: We propose a new type of functional imaging in magnetic resonance imaging (MRI), a functional MR angiography (fMRA). As it is known, arterial responses during neural activities have been studied in animals, but little is known about the human brain in-vivo. Proposed fMRA at ultra-high field strength, 7.0 Tesla (T), has a potential for a direct visualization of vascular responses of those blood vessels related to the neural activity during the tasks, such as the hand movement or checker board stimulation, that is, fMRA. The results of this paper clearly indicate that there is the possibility that one can directly observe the vascular changes in individual blood vessels related to the tasks in human brain in-vivo, similar to fMRI.
NeuroImage 09/2008; 42(1):70-5. · 5.89 Impact Factor
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ABSTRACT: We sought to examine the feasibility of observing the lenticulostriate arteries (LSAs) noninvasively by ultrahigh-field MRI with 7.0T.
We used 3-dimensional time-of-flight MR angiography with a radiofrequency coil optimized for 7.0T MRI. We examined the LSAs of 6 healthy subjects and compared 7.0T MR angiography images with 1.5T ones to examine the potentials of ultrahigh-field MRI for angiography.
The results show clear details of LSAs and their distribution in the normal healthy subjects with large variations in the shapes, the number of branches and the sites of origin. We also observed substantial differences between the left and right sides within each subject. Although we studied only 6 subjects, we found no age- or gender-related differences in the LSAs.
The visualization of microvasculature of the brain, such as LSAs, using 7.0T MR angiography, is possible in in vivo human studies noninvasively. We, therefore, believe that it could play a major role in the study of small vascular abnormalities, such as the early stages of cerebral strokes.
Stroke 06/2008; 39(5):1604-6. · 5.73 Impact Factor
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ABSTRACT: Parkinson disease (PD) is a well-known degenerative disease resulting in the depletion of dopamine-producing neurons in the pars compacta of the substantia nigra. Adenoviral vector delivery of neurotrophic factors may provide a potential therapy for PD. The authors examined whether glial cell line-derived neurotrophic factor (GDNF) delivered via adenoviral vector (Ad-GDNF) could promote functional recovery in a rat model of PD. Additionally, they examined whether neural precursor cells (NPCs) provide the therapeutic potential of cultured neural cells for cell regeneration and replacement in PD.
All animals underwent stereotactic injection of 6-hydroxydopamine into the right substantia nigra. Eight weeks later, the rats were tested for apomorphine-induced rotational asymmetry and evaluation of explanted grafts infected with the complementary DNA for GDNF containing NPCs and NPCs alone. In the NPC cultures of embryonic rat striata, the authors found that basic fibroblast growth factor induced the proliferation of stem cells, which give rise to spheres of undifferentiated cells that generate neurons and glia.
In this study the authors found that the reduction of apomorphine-induced rotation was more prominent in parkinsonian rats that received Ad-GDNF-treated grafts containing NPCs (61%) than in those that received grafts of NPCs alone (16%).
Neurosurgical FOCUS 08/2003; 15(1):ECP1. · 2.87 Impact Factor
