Seung-Kug Baik

Topographical differences of brain iron deposition between progressive supranuclear palsy and parkinsonian variant multiple system atrophy

OBJECTIVE There have been various studies showing increased iron levels in parkinsonian disorders. The purpose of this study was to demonstrate topographical differences of brain iron deposition between progressive supranuclear palsy (PSP) and the parkinsonian variant of multiple system atrophy (MSA-p) with SWI images. METHODS A total of 11 patients with PSP, 12 with MSA-p, 15 with Parkinsons disease (PD), and 20 age-matched healthy controls underwent SWI of the brain. Mean phase shift values of the red nucleus (RN), substantia nigra (SN), head of the caudate nucleus (CN), globus pallidus (GP), putamen (PUT), and thalamus (TH) were calculated and compared between groups. A voxel-based analysis of the processed SWI was performed to determine topographical differences of iron-related hypointense signals in PUT, GP, and TH. RESULTS Patients with PSP and MSA-p had significantly higher levels of iron deposition than control and PD groups. Comparing patients with PSP and MSA-p, differences were found in iron concentrations of the RN, SN, GP, and TH, which were higher in the PSP group. However, iron levels in the PUT were higher in the MSA group (p<0.05). The area under curve (AUC) indicated that the PUT was the most valuable nucleus in differentiating MSA-p from PSP and PD according to phase shift values (AUC=0.836). Meanwhile the GP (AUC=0.869) and TH (AUC=0.884) were the two most valuable nuclei in differentiating PSP from MSA-p and PD. Voxel-based analysis showed subregional differences in iron-related hypointense signals in the PUT, GP, and TH between MSA-p and PSP groups. Patients with MSA-p had significant increases of iron-related hypointense signals in the posterolateral PUT and adjacent lateral aspect of the GP, whereas the PSP group had increased hypodense signals in the anterior and medial aspects of the GP and TH. CONCLUSION Our data demonstrate that pathological iron accumulations are more prevalent and severe in PSP compared to MSA-p. The distribution of high-iron-content regions in this study reflects pathoanatomically relevant sites. This finding allows for the use of MRI-based brain iron mapping as a technique to indirectly identify pathological changes.

Acute serious rebleeding after angiographically successful coil embolization of ruptured cerebral aneurysms

PurposeThe present study investigated the incidence of acute rebleeding after successful coil embolization of a ruptured cerebral aneurysm, including clinical outcomes, and possible mechanisms of the events other than coil compaction and/or incomplete embolization.Materials and methodsThis study included 591 consecutive patients who presented with aneurysmal subarachnoid hemorrhage, were treated with coil embolization, and whose post-procedural angiography revealed successful embolization. Data were collected retrospectively from six patients who showed acute rebleeding despite that angiographically successful coil embolization was achieved. All clinical, radiological data and intraoperative videos were reviewed to identify causative factors which could have contributed to the occurrence of rebleeding.ResultsIncidence of acute rebleeding after successful coil embolization of ruptured cerebral aneurysm was 1.0% (6/591). In all of these six patients, complete angiographic occlusion was achieved except in one case where a small residual neck was intentionally left to avoid compromise of the parent artery. Four of the six patients showed poor clinical courses, either died or recovered with severe disability. Whenever possible, we performed an immediate craniotomy for exploration and additional clipping. Based on intraoperative findings, we hypothesized that uneven distribution of the coil masses and spontaneous resolution of thrombus among the strands of coil (inter-coil-loop thrombolysis) could be possible mechanisms of rebleeding.ConclusionAcute rebleeding is extremely rare, but is possible as a complication of coil embolization of a ruptured cerebral aneurysm even when a case is angiographically successful. The higher degree of morbidity and mortality is a major concern. Therefore, further investigation to discover risk factors and causative mechanisms for such a complication is sorely needed.

Widespread cerebral cortical mineralization in Wilson's disease detected by susceptibility-weighted imaging.

Signal abnormalities of cortical gray matter, compared with the deep nuclear structures, have received less attention in Wilsons disease (WD). They nearly always accompanied white matter signal change, and commonly are associated with epilepsy and psychiatric features. We report herein two cases diagnosed as WD who, in addition to characteristic deep nuclear lesions on MR imaging, had widespread cerebral cortical paramagnetic signals dramatically detected by susceptibility-weighted imaging. T2-weighted MR images did not show any cortico-subcortical hyperintense lesions. To our knowledge, these findings have not been described before and may help to further characterize the disease.

Characterizing paramagnetic signal in a patient with Wilson's disease by susceptibility-weighted imaging

Department of Neurology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea Department of Nuclear medicine, Medical Research Institute, Pusan National University Hospital, Busan, South Korea Department of Neurology and Radiology, Medical Research Institute, Pusan National University Yangsan Hospital, Yangsan, South Korea

Demonstration of striatopallidal iron deposition in chorea-acanthocytosis by susceptibility-weighted imaging

Chorea-acanthocytosis (ChAc) is a rare hereditary disorder characterized by involuntary choreiform movements and erythrocytic acanthocytosis [1]. MRI commonly shows a T2-signal increase in the atrophic striatum, which reveals neuronal loss with gliosis on autopsy. Increased brain iron levels are seen in various neurodegenerative diseases [2–5] and can be easily detected by newer MR imaging technologies, such as susceptibility-weighted imaging (SWI) [2, 3]. We attempted to visualize areas of degenerative change according to abnormal iron deposition in ChAc by using SWI. A 35-year-old woman presented with exacerbation of orolingual dyskinesia, dysarthria and cognitive decline during the course of 3 years. There was no family history of similar neurological disorders. Neurological examination revealed orofaciolingual dyskinesia and intermittent choreiform movements of the head and neck. There was involuntary tongue protrusion and self-mutilating behaviour affecting the tongue and lips. Also, her speech was dysarthric. Muscle power and bulk, and sensory function were all intact. She could walk without difficulty. Hyporeflexia was present in the lower limbs. On laboratory examination, the serum creatine kinase (CK) level was elevated at 345 IU/l (normal range 5–217 IU/l). Serum lipids and lipoprotein electrophoresis were normal. There were no abnormal findings in the nerve conduction study, including electromyography, muscle CT and EEG. Cardiomyopathy, cardiac arrhythmia and hepatosplenomegaly were absent. Genetic tests for Huntington’s disease, DRPLA, and spinocerebellar ataxia 1, 2, 3 and 17 were all negative. Peripheral blood smear revealed 20% acanthocytes confirmed by scanning electron microscopy (Fig. 1a). Brain MR imaging (3.0-T MR system, Verio, Siemens, Germany) revealed the bilateral atrophic putamina and head of caudate nuclei with increased signal intensity on T2-weighted (Fig. 1b) and iso-signal intensity on T1-weighted imaging. SWI (TR = 28 ms, TE = 20 ms, flip angle = 20 slice thickness = 2 mm) showed a paramagnetic dark signal in both striata (Fig. 1c), the corresponding area to T2 hyperintensity. Also, dark condensed stripes were observed in the lateral pallidum (arrows, Fig. 1d). Such a paramagnetic signal was not prominent in conventional gradient echo sequences (Fig. 1e). No evidence of calcification or hemorrhage was observed on brain CT (Fig. 1f). Genetic screening for VPS13A gene or Western blot for chorein was not available. The clinical presentation of this patient most likely fits with ChAc. However, correct clinical diagnosis is difficult due to symptom overlap with McLeod syndrome (MLS) [1]. Although neither mutations of the XK gene nor Kell antigen expression was looked for in this patient, the diagnosis of MLS is unlikely based on the lack of J.-H. Lee (&) Department of Neurology, Medical Research Institute, Pusan National University Yangsan Hospital, Beomo-ri, Mulgum-eup, Yangsan-si, Gyeongsangnam-do 626-770, South Korea e-mail: jhlee.neuro@pusan.ac.kr

Nigropallidal iron accumulation in pantothenate kinase-associated neurodegeneration demonstrated by susceptibility-weighted imaging

Neurodegeneration with brain iron accumulation (NBIA, formerly known as Hallervorden-Spatz syndrome) defines a group of genetic disorders characterized by brain iron deposition. The major form of NBIA is pantothenatekinase associated neurodegeneration, or PKAN, caused by mutations in the PANK2 gene [1, 2]. The other known causes of NBIA include neuroferritinopathy, infantile neuroaxonal dystrophy, and aceruloplasminemia [2, 3]. Because of extensive phenotypic overlap, the clinical diagnosis of different subtypes of NBIA can be challenging, particularly in the early stages [2, 3]. Previous MRI studies with an emphasis on T2-weighted imaging (T2WI) demonstrated a central region of hyperintensity in the globus pallidus with surrounding hypointensity, called an eye-of-the-tiger sign [1, 2]. Newer MR imaging technologies, susceptibility-weighted imaging (SWI), has been shown to be superior in its ability to demonstrate brain iron deposition than other conventional MR imaging [4]. We report herein SWI findings in a patient with PKAN2 gene mutation to characterize the patterns of iron deposition in this disorder. A 17-year-old boy presented with dysarthria and progressive generalized dystonia for 2 years. Initially, he developed twisting postures in his right hand, which progressively worsened and spread to involve the neck, trunk, and his left arm. His birth, perinatal, growth and development histories were unremarkable. There was no family history of neurological disorders. On examination, he showed blepharospasm, retrocollis, and backward tilting of the trunk. He complained of severe pain in his left shoulder which took an intermittent dystonic posture with internal rotation. He also had dystonic posture in both hands and feet. However, he could walk without difficulty. The result of neuropsychological tests showed mild mental retardation. Ophthalmic examination revealed no Kayser-Fleisher rings, optic neuropathy, or pigmentary retinopathy. His motor, sensory, and cerebellar function tests were normal. Deep tendon reflexes were normoactive, and plantar reflexes were flexor bilaterally. Routine laboratory tests were all normal as well as measurements of serum ceruloplasmin, CK, ferritin, and lactate levels. EEG was normal. Brain magnetic resonance imaging showed the eye-of-the-tiger sign on T2-weighted imaging (Fig. 1a). Susceptibility-weighted images dramatically showed the tracts of iron deposition from substantia nigra to globus pallidus (Fig. 1c–f). Genetic testing confirmed compound heterozygous mutations in exon 3 [c. (999A [ G), p. (K335E)] and exon 4 [c. (1270_1272del), p. (L424del)] in the PKAN2 gene. MRI has been particularly useful in distinguishing the forms of NBIA. The eye-of-the-tiger sign (Fig. 1a) is specific for PKAN and showed a high correlation with the presence of a PANK2 mutation [1, 2]. However, the J.-H. Lee (&) D.-S. Kim Department of Neurology, Medical Research Institute, Pusan National University Yangsan Hospital, Beomo-ri, Mulgum-eup, Gyeongnam 626-770, Korea e-mail: drleejae@hanmail.net; jhlee.neuro@pusan.ac.kr

Proton magnetic resonance spectroscopic findings of cerebral fat embolism induced by triolein emulsion in cats.

Background: In experimental studies, embolization of the cerebral hemisphere with triolein emulsion has revealed reversible magnetic resonance imaging (MRI) findings in the subacute stage. Purpose: To investigate the changes in the major metabolites, by proton magnetic resonance spectroscopy (MRS), in a cerebral fat embolism induced by a triolein emulsion. Material and Methods: The internal carotid arteries of 19 cats were injected with a triolein emulsion, and multivoxel MRS was performed 30 min, 1 day, and 7 days later. In the control group, six cats were injected with normal saline. The MR spectra were evaluated for N-acetyl aspartate (NAA), creatine (Cr), and choline (Cho), along with the presence of lipid and lactate. Semiquantitative analyses of NAA/Cr, Cho/Cr, NAA/Cho, and lipid/Cr ratios compared the median values of the ipsilateral metabolite ratios with those of the contralateral side and in the control group for each point in time. Results: The NAA/Cr, Cho/Cr, and NAA/Cho ratios in the ipsilateral cerebral hemisphere of the embolized group after 30 min, 1 day, and 7days were not significantly different from the contralateral hemisphere of the embolized and control groups (P>0.05). The lipid/Cr ratio in the ipsilateral cerebral hemisphere of the embolized group was significantly higher when compared with the control group (P=0.012 at 30 min, P=0.001 on day 1, and P=0.018 on day 7). Conclusion: Cerebral fat embolism induced by a triolein emulsion resulted in no significant change in the major metabolites of the brain in the acute stage, except for an elevated lipid/Cr ratio, which suggests the absence of any significant hypoxic-ischemic changes in the lesions embolized using a fat emulsion.

Recurrent arteriovenous malformation on palate after embolization combined surgical resection: preoperative magnetic resonance features and intraoperative angiographic findings

Angiography is the gold standard for the diagnosis and complete resection of arteriovenous malformations (AVMs). The absence of residual AVM after surgery is commonly believed to reduce the risk of future hemorrhage. However, AVMs can recur after proven complete angiographic resection can occur, albeit rarely, especially in the pediatric population. We report a rare case of a recurrent AVM two years after complete resection in an adult patient. This case report shows that AVMs in adults can recur despite their rarity and despite postoperative angiography confirming complete removal. Moreover, in this case, the recurrent AVM involved a new feeding vessel that was not involved with the initial lesion.

E-059 Distally enlarged feeding artery phenomenon in intracranial dural arteriovenous fistula: alternative access route to transarterial intravenous embolization

Background Transvenous (TV) embolization is ideal for endovascular treatment of intracranial dural arteriovenous fistulas (DAVF). However, it is not always feasible because of various factors, and transarterial (TA) embolization could then be tried. Objective We aimed to determine the incidence of ‘distally enlarged feeding artery phenomenon’ and the major feeding artery in DAVF. In case TV approach is difficult and this phenomenon observed, we could use this vessel for transarterial intravenous (TAIV) embolization as an endovascular treatment modality for DAVF. Methods Forty-four patients with intracranial DAVF treated using endovascular procedure between 2009 and 2016 were retrospectively reviewed. Their clinical records, angiography reports, embolization procedure notes were studied and their angiographies were chronologically classified into proliferative and restrictive types. Results In 14 of 44 patients (32%), we observed the ‘distally enlarged feeding artery phenomenon.’ The most common enlarged artery was the middle meningeal artery. The distally enlarged feeding artery group was predominantly the restrictive type, while the other group was proliferative in nature. Of the 14 cases, seven patients underwent TAIV embolization, while the other seven underwent TV embolization. Conclusion Abstract E-059 Figure 1 Disclosures D. Shim: None. Y. Kim: None. S. Baik: None.

P-027 Neurointervention simulation using patient-specific 3d printing model: from lab to real angio suite

Background Endovascular treatment is evolving field and acceptable complication rate getting lower. In addition, changes in practice patterns have decreased the volume of specific cases for each practitioner, such as aneurysm coiling, which reduces the opportunity for intervention suite. Therefore, practitioners need training for endovascular treatment for their certified experience and procedural skills. In addition, even expert also need patient specific model for planning patient treatment, and training new developed device. Objective The authors developed a hands-on, dimensionally patient specific model for aneurysm coiling using patient anatomic data and three-dimensional (3D) printing. Design of the model focused on prevalence of aneurysm, level of difficulty and point of teaching. We report a preliminary series of endovascular planning with 3D printed aneurysm model. Methods An aneurysm model was printed based on the patient data acquired from the 3D rotational angiogram and CT angiography. A hollow aneurysm model with an identical vessel and aneurysm lumen to the actual anatomy was constructed with use of the 3D printed model as a mold and 3D virtual molding technique. Results Through the 3D manufacturing process, a patient-derived simulator was developed for endovascular treatment before procedure. A microcatheter shaping mandrel was formed to identically line the 3D curvature of the parent vessel and the long axis of the aneurysm. With use of the model, treatment plan was more precise and procedure time also shorter. Also learner could practice same patient model for their training without any complication. They can shape microcatheter and validated for the accuracy with the model. Conclusions The proposed aneurysm coiling simulator has the potential to improve learning experiences in medical environment. 3D printing and elastomeric casting can produce patient-specific models for treatment planning that add value to endovascular training and preparation. Abstract P-027 Figure 1 Disclosures Y. Kim: None. S. Baik: None. S. Lee: None.