First-Pass Recanalization with EmboTrap II in Acute Ischemic Stroke (FREE-AIS): A Multicenter Prospective Study

Objective@#We aimed to evaluate the efficacy of EmboTrap II in terms of first-pass recanalization and to determine whether it could yield favorable outcomes. @*Materials and Methods@#In this multicenter, prospective study, we consecutively enrolled patients who underwent mechanical thrombectomy using EmboTrap II as a front-line device. The primary outcome was the first pass effect (FPE) rate defined by modified Thrombolysis In Cerebral Infarction (mTICI) grade 2c or 3 by the first pass of EmboTrap II. In addition, modified FPE (mFPE; mTICI grade 2b–3 by the first pass of EmboTrap II), successful recanalization (final mTICI grade 2b–3), and clinical outcomes were assessed. We also analyzed the effect of FPE on a modified Rankin Scale (mRS) score of 0–2 at 3 months. @*Results@#Two hundred-ten patients (mean age ± standard deviation, 73.3 ± 11.4 years; male, 55.7%) were included. Ninetynine patients (47.1%) had FPE, and mFPE was achieved in 150 (71.4%) patients. Successful recanalization was achieved in 191 (91.0%) patients. Among them, 164 (85.9%) patients underwent successful recanalization by exclusively using EmboTrap II. The time from groin puncture to FPE was 25.0 minutes (interquartile range, 17.0–35.0 minutes). Procedure-related complications were observed in seven (3.3%) patients. Symptomatic intracranial hemorrhage developed in 14 (6.7%) patients. One hundred twenty-three (58.9% of 209 completely followed) patients had an mRS score of 0–2. Sixteen (7.7% of 209) patients died during the follow-up period. Patients who had successful recanalization with FPE were four times more likely to have an mRS score of 0–2 than those who had successful recanalization without FPE (adjusted odds ratio, 4.13;95% confidence interval, 1.59–10.8; p = 0.004). @*Conclusion@#Mechanical thrombectomy using the front-line EmboTrap II is effective and safe. In particular, FPE rates were high. Achieving FPE was important for an mRS score of 0–2, even in patients with successful recanalization.

XperCT-guided Intra-cisterna Magna Injection of Streptozotocin for Establishing an Alzheimer’s Disease Model Using the Cynomolgus Monkey (Macaca fascicularis)

Till date, researchers have been developing animal models of Alzheimer’s disease (AD) in various species to understand the pathological characterization and molecular mechanistic pathways associated with this condition in humans to identify potential therapeutic treatments. A widely recognized AD model that mimics the pathology of human AD involves the intracerebroventricular (ICV) injection with streptozotocin (STZ).However, ICV injection as an invasive approach has several limitations related to complicated surgical procedures. Therefore, in the present study, we created a customized stereotaxic frame using the XperCT-guided system for injecting STZ in cynomolgus monkeys, aiming to establish an AD model. The anatomical structures surrounding the cisterna magna (CM) were confirmed using CT/MRI fusion images of monkey brain with XperCT, the c-arm cone beam computed tomography. XperCT was used to determine the appropriate direction in which the needle tip should be inserted within the CM region. Cerebrospinal fluid (CSF) was collected to confirm the accurate target site when STZ was injected into the CM.Cynomolgus monkeys were administered STZ dissolved in artificial CSF once every week for 4 weeks via intracisterna magna (ICM) injection using XperCT-guided stereotactic system. The molecular mechanisms underlying the progression of STZ-induced AD pathology were analyzed two weeks after the final injection. The monkeys subjected to XperCT-based STZ injection via the ICM route showed features of AD pathology, including markedly enhanced neuronal loss, synaptic impairment, and tau phosphorylation in the hippocampus. These findings suggest a new approach for the construction of neurodegenerative disease models and development of therapeutic strategies.

Dilatation of Superior Ophthalmic Vein and Visual Disturbance by Central Venous Stenosis: A Case Mimicking Cavernous Sinus Dural Arteriovenous Fistula

Central venous stenosis is a relatively common complication in hemodialysis patients; however, jugular venous reflux (JVR) and increased intracranial pressure are rare, and associated progressive visual disturbance was reported in only a few cases. Here, we report a case of JVR with visual disturbance and increased intracranial pressure. Notably, the MRI was accompanied by a dilatation of the superior ophthalmic vein, which was mistaken for a cavernous sinus dural arteriovenous fistula (CSdAVF). The patient had JVR on time-of-flight MR angiography (TOF-MRA) and severe stenosis of the left brachiocephalic vein on conventional angiography. After balloon angioplasty for central venous stenosis, he was discharged after improvement of his visual disturbance. Although JVR due to central venous stenosis and CSdAVF might show similar symptoms, treatment plans are different. Therefore, it is important to distinguish radiologically based on a thorough review of MRI and TOF-MRA and confirm the central venous stenosis on cerebral angiography for the accurate diagnosis.

Assessment of Hand Motor Function in a Non-human Primate Model of Ischemic Stroke

Ischemic stroke results from arterial occlusion and can cause irreversible brain injury. A non-human primate (NHP) model of ischemic stroke was previously developed to investigate its pathophysiology and for efficacy testing of therapeutic candidates; however, fine motor impairment remains to be well-characterized. We evaluated hand motor function in a cynomolgus monkey model of ischemic stroke. Endovascular transient middle cerebral artery occlusion (MCAO) with an angiographic microcatheter induced cerebral infarction. In vivo magnetic resonance imaging mapped and measured the ischemia-induced infarct lesion. In vivo diffusion tensor imaging (DTI) of the stroke lesion to assess the neuroplastic changes and fiber tractography demonstrated three-dimensional patterns in the corticospinal tract 12 weeks after MCAO. The hand dexterity task (HDT) was used to evaluate fine motor movement of upper extremity digits. The HDT was modified for a home cage-based training system, instead of conventional chair restraint training. The lesion was localized in the middle cerebral artery territory, including the sensorimotor cortex. Maximum infarct volume was exhibited over the first week after MCAO, which progressively inhibited ischemic core expansion, manifested by enhanced functional recovery of the affected hand over 12 weeks after MCAO. The total performance time decreased with increasing success rate for both hands on the HDT. Compensatory strategies and retrieval failure improved in the chronic phase after stroke. Our findings demonstrate the recovery of fine motor skill after stroke, and outline the behavioral characteristics and features of functional disorder of NHP stroke model, providing a basis for assessing hand motor function after stroke.

Increased CD68/TGFβ Co-expressing Microglia/Macrophages after Transient Middle Cerebral Artery Occlusion in Rhesus Monkeys

The function of microglia/macrophages after ischemic stroke is poorly understood. This study examines the role of microglia/macrophages in the focal infarct area after transient middle cerebral artery occlusion (MCAO) in rhesus monkeys. We measured infarct volume and neurological function by magnetic resonance imaging (MRI) and non-human primate stroke scale (NHPSS), respectively, to assess temporal changes following MCAO. Activated phagocytic microglia/macrophages were examined by immunohistochemistry in post-mortem brains (n=6 MCAO, n=2 controls) at 3 and 24 hours (acute stage), 2 and 4 weeks (subacute stage), and 4, and 20 months (chronic stage) following MCAO. We found that the infarct volume progressively decreased between 1 and 4 weeks following MCAO, in parallel with the neurological recovery. Greater presence of cluster of differentiation 68 (CD68)-expressing microglia/macrophages was detected in the infarct lesion in the subacute and chronic stage, compared to the acute stage. Surprisingly, 98~99% of transforming growth factor beta (TGFβ) was found colocalized with CD68-expressing cells. CD68-expressing microglia/macrophages, rather than CD206⁺ cells, may exert anti-inflammatory effects by secreting TGFβ after the subacute stage of ischemic stroke. CD68⁺ microglia/macrophages can therefore be used as a potential therapeutic target.

Does Multiphasic Contrast Enhanced Fluid Attenuated Inversion Recovery Magnetic Resonance Imaging Enhance the Detectability of Small Intracerebral Metastases?

PURPOSE@#To determine adequate timing of acquisition of contrast-enhanced fluid attenuated inversion recovery (FLAIR) by using multiphasic contrast-enhanced FLAIR magnetic resonance imaging (MRI) and to evaluate added value in detecting small intracerebral metastases 5 mm or less.@*MATERIALS AND METHODS@#Twenty-nine patients, that underwent multiphasic contrast-enhanced FLAIR MRI and contrast-enhanced T1 weighted image (T1WI) were included and total number of small intracerebral metastases was 131. Sensitivity, specificity and accuracy of lesion detection were evaluated. Contrast ratio (CR) and enhancement ratio of each lesion were compared and analyzed among each imaging sequence.@*RESULTS@#Sensitivity, specificity and accuracy of lesion detection were increased when contrast-enhanced FLAIR was added to contrast-enhanced T1WI. Area of under receiver operating characteristic curve significantly increased by addition of contrast-enhanced FLAIR than using contrast-enhanced T1WI alone (p < 0.05). CR was significantly higher in contrast-enhanced T1WI than FLAIR (p < 0.001). All of the above results were not different according to time of acquisition of contrastenhanced FLAIR.@*CONCLUSION@#There was advantage of conducting contrast-enhanced FLAIR MRI, but multiphasic contrast-enhanced FLAIR did not provide additional information for detection of small intracerebral metastases compared with single-phase FLAIR MRI.

A Potential Diagnostic Pitfall in the Differentiation of Hemorrhagic and Fatty Lesions Using Short Inversion Time Inversion Recovery: a Case Report

Short inversion time inversion recovery (STIR) is widely used for spinal magnetic resonance imaging (MRI) because the pulse sequence of STIR is insensitive to magnetic field inhomogeneity and can be used to scan a large field of view. In this case report, we present a case of spinal epidural hematoma with unexpected signal decrease on a STIR image. The MRI showed an epidural mass that appeared with high signal intensity on both T1- and T2-weighted images. However, a signal decrease was encountered on the STIR image. This nonspecific decrease of signal in tissue with a short T1 relaxation time that is similar to that of fat (i.e., hemorrhage) could lead to a diagnostic pitfall; one could falsely diagnose this decrease of signal as fat instead of hemorrhage. Awareness of the nonselective signal suppression achieved with STIR pulse sequences may avert an erroneous diagnosis in image interpretation.

Infratentorial and Intraparenchymal Subependymoma in the Cerebellum: Case Report

Subependymomas are rare benign tumors located in the ventricular system. Intraparenchymal subependymoma is extremely rare; only 6 cases have been reported, and all were located in the supratentorial region. We describe a case of infratentorial, intraparenchymal subependymoma in a 28-year-old man with intermittent headache. Imaging revealed a well-demarcated cystic and solid cerebellar mass near the fourth ventricle. The mass had a microcystic component and calcification without contrast enhancement. Complete surgical excision was performed, and histopathology confirmed a subependymoma.

Multimodal Imaging Follow-up of a Thrombosed Developmental Venous Anomaly: CT, CT Angiography and Digital Subtraction Angiography / 신경중재치료의학

We report a rare case of thrombosed developmental venous anomaly (DVA) in a 31-year old male with hemorrhagic cerebral venous infarction at the initial clinical presentation. In this case, sequential CT, CT angiography and digital subtraction angiography demonstrated thrombotic obstruction of the venous drainage from DVA, its progressive recanalization and temporal evolution of the affected brain parenchyma. The relevant previous literatures were reviewed and summarized.

True Progression versus Pseudoprogression in the Treatment of Glioblastomas: A Comparison Study of Normalized Cerebral Blood Volume and Apparent Diffusion Coefficient by Histogram Analysis

OBJECTIVE: The purpose of this study was to differentiate true progression from pseudoprogression of glioblastomas treated with concurrent chemoradiotherapy (CCRT) with temozolomide (TMZ) by using histogram analysis of apparent diffusion coefficient (ADC) and normalized cerebral blood volume (nCBV) maps. MATERIALS AND METHODS: Twenty patients with histopathologically proven glioblastoma who had received CCRT with TMZ underwent perfusion-weighted imaging and diffusion-weighted imaging (b = 0, 1000 sec/mm2). The corresponding nCBV and ADC maps for the newly visible, entirely enhancing lesions were calculated after the completion of CCRT with TMZ. Two observers independently measured the histogram parameters of the nCBV and ADC maps. The histogram parameters between the true progression group (n = 10) and the pseudoprogression group (n = 10) were compared by use of an unpaired Student's t test and subsequent multivariable stepwise logistic regression analysis to determine the best predictors for the differential diagnosis between the two groups. Receiver operating characteristic analysis was employed to determine the best cutoff values for the histogram parameters that proved to be significant predictors for differentiating true progression from pseudoprogression. Intraclass correlation coefficient was used to determine the level of inter-observer reliability for the histogram parameters. RESULTS: The 5th percentile value (C5) of the cumulative ADC histograms was a significant predictor for the differential diagnosis between true progression and pseudoprogression (p = 0.044 for observer 1; p = 0.011 for observer 2). Optimal cutoff values of 892 x 10-6 mm2/sec for observer 1 and 907 x 10-6 mm2/sec for observer 2 could help differentiate between the two groups with a sensitivity of 90% and 80%, respectively, a specificity of 90% and 80%, respectively, and an area under the curve of 0.880 and 0.840, respectively. There was no other significant differentiating parameter on the nCBV histograms. Inter-observer reliability was excellent or good for all histogram parameters (intraclass correlation coefficient range: 0.70-0.99). CONCLUSION: The C5 of the cumulative ADC histogram can be a promising parameter for the differentiation of true progression from pseudoprogression of newly visible, entirely enhancing lesions after CCRT with TMZ for glioblastomas.

MR Imaging of Primary Retroperitoneal Mucinous Cystadenocarcinoma in Pregnant Woman

Primary retroperitoneal mucinous cystadenocarcinoma is a very rare malignancy. To date, 51 cases have been reported, including 3 in pregnant women. Herein, we report magnetic resonance findings of a 31-year-old Korean woman (15 weeks and 3 days pregnant) with primary retroperitoneal mucinous cystadenocarcinoma. On abdominal magnetic resonance imaging (MRI), a mass was identified in the retroperitoneal area with a nodular lesion showing heterogeneous signal intensity and focal wall thickening on T1- and T2-weighted images. Exploratory laparotomy and tumor excision were performed. Histological examination revealed primary retroperitoneal mucinous cystadenocarcinoma. The patient subsequently underwent total hysterectomy, bilateral salpingo-oophorectomy, and omentectomy for metastatic mucinous cystadenocarcinoma of both ovaries 15 months after her initial surgery.

Subcutaneous Fat Necrosis of the Newborn: A Case Report

Subcutaneous fat necrosis in the newborn is an uncommon transient disorder of the subcutaneous adipose tissue that develops after birth. We describe the characteristic ultrasonography and CT findings of a case of pathologically confirmed subcutaneous fat necrosis located at the subcutaneous fat layer of the neck, back, and shoulders with a review of the literature.

Differential Diagnosis of a Follicular Carcinoma and Papillary Carcinoma of the Thyroid Gland Based on Sonographic Findings

PURPOSE: The purpose of this study was to evaluate and compare the sonographic findings of a conventional papillary carcinoma, follicular carcinoma and a follicular variant of a papillary carcinoma. MATERIALS and METHODS: A total of 308 nodules from 231 patients that were diagnosed with a papillary carcinoma and a follicular carcinoma by surgery after sonography were analyzed. The nodules consisted of a conventional papillary carcinoma (255, 83%), a follicular variant of a papillary carcinoma (25, 8%), and a follicualar carcinoma (28, 9%). We compared and analyzed the sonographic findings of each nodule for content, margin, echotexture, shape, calcification and halo sign. RESULTS: A conventional papillary carcinoma showed significant different sonographic findings than a follicular carcinoma and a follicular variant of a papillary carcinoma for an ill-defined or well-defined spiculated margin (63.1%), marked hypoechogenicity (85.9%) and microcalcification (49%). A follicular carcinoma showed a significant difference than a conventional papillary carcinoma for a well-defined smooth margin (92.9%), iso, hypo- or hyperechogenicity (89.3%), wider than tall shape (100%) and halo sign (82.1%). The follicular variant of a papillary carcinoma showed similar findings to a follicular carcinoma except for marked hypoechogenicity (44%, p = 0.006) and taller than wide shape (16%, p = 0.027). CONCLUSION: The follicular carcinoma and follicular variant of a papillary carcinoma showed similar sonographic findings, but findings of a conventional papillary carcinoma were different.

Methods of Counting Ribs on Chest CT: The Modified Sternomanubrial Approach

PURPOSE: The purpose of this study was to evaluate the accuracy of each method of counting ribs on chest CT and to propose a new method: the anterior approach with using the sternocostal joints. MATERIALS AND METHODS: CT scans of 38 rib lesions of 27 patients were analyzed (fracture: 25, metastasis: 11, benign bone disease: 2). Each lesion was independently counted by three radiologists with using three different methods for counting ribs: the sternoclavicular approach, the xiphisternal approach and the modified sternomanubrial approach. The rib lesions were divided into three parts for evaluation of each method according to the location of the lesion as follows: the upper part (between the first and fourth thoracic vertebra), the middle part (between the fifth and eighth) and the lower part (between the ninth and twelfth). RESULTS: The most accurate method was a modified sternomanubrial approach (99.1%). The accuracies of a xiphisternal approach and a sternoclavicular approach were 95.6% and 88.6%, respectively. A modified sternomanubrial approach showed the highest accuracies in all three parts (100%, 100% and 97.9%, respectively). CONCLUSION: We propose a new method for counting ribs, the modified sternomanubrial approach, which was more accurate than the known methods in any parts of the bony thorax, and it may be an easier and quicker method than the others in clinical practice.