Longitudinal Changes in Iron and Myelination Within Ischemic Lesions Associate With Neurological Outcomes: A Pilot Study.

BACKGROUND: Combined quantitative susceptibility mapping and R2* relaxometry can distinguish iron and myelin components in ischemic lesions. We aimed to investigate whether longitudinal changes in magnetic susceptibility and R2* values within ischemic lesions were associated with neurological outcomes. METHODS: In this single-center prospective study, we included patients, 20 to 90 years of age, who were consecutively admitted to the stroke care unit between August 2020 and March 2022 due to acute ischemic stroke. The participants underwent 2 instances of quantitative susceptibility mapping and R2* relaxometry scanning before and after stroke rehabilitation. We compared the changes in these quantitative measures across different subtypes of acute ischemic stroke. Multiple linear regression models were used to investigate the associations between the National Institutes of Health Stroke Scale scores and the mean magnetic susceptibility and R2* values in ischemic lesions. RESULTS: Among a total of 112 patients with acute ischemic stroke, 32 participants (aged 73.3±9.4 years; 20 men and 12 women) were evaluated. The median time from stroke onset to the first imaging was 5 days and that to the second imaging was 102 days. The changes in magnetic susceptibility values of branch atheromatous disease were higher than those of cardioembolism (mean difference, 0.018 [95% CI, 0.009-0.027] ppm; P<0.001) and lacunar (mean difference, 0.013 [95% CI, 0.005-0.020] ppm; P=0.004). Across all patients, the changes in National Institutes of Health Stroke Scale scores were associated with those of magnetic susceptibility values (coefficient, 0.311 [95% CI, 0.098-0.520]; P=0.017) but not with R2* values (coefficient, 0.114 [95% CI, -0.127 to 0.345]; P=0.291). CONCLUSIONS: The longitudinal changes in the magnetic susceptibility values within ischemic lesions were associated with neurological outcomes during the restorative stages poststroke in patients experiencing acute ischemic stroke. REGISTRATION: URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000050719.

Early-onset Alzheimer Disease Associated With Neuromyelitis Optica Spectrum Disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disease of the central nervous system. Although recent reports have noted that cognitive impairment is common in NMOSD, little longitudinal information is available on the trajectories of cognitive function in the disease. Here, we report a case of a 55-year-old woman with an 11-year history of NMOSD who visited our memory clinic for progressive memory loss. She was diagnosed with early-onset Alzheimer disease based on amyloid and tau positron emission tomography imaging biomarkers. This is the first report of early-onset Alzheimer disease in a patient with NMOSD. Complications of Alzheimer disease should be considered when patients with NMOSD exhibit rapid cognitive decline. More longitudinal studies of NMOSD with cognitive impairment are needed.

Concurrent cerebral infarction and intracranial tuberculoma induced by the carotid plaque complicated with miliary tuberculosis.

Cerebrovascular complications of central nervous system tuberculosis (TB) are predictors of poor prognosis and adverse outcomes. These complications are mainly intracranial arterial involvement, with occasional venous involvement. Here, we present a 67-year-old woman with concurrent cerebral infarction and intracranial tuberculoma induced by the carotid plaque complicated by miliary tuberculosis. Mycobacterium tuberculosis was observed on the luminal side of the carotid plaques in pathological specimens. Treatment with anti-TB drugs alone would likely not cure the patient, as M. tuberculosis would continue to disseminate. Endarterectomy could directly remove the embolic source, and a complete cure was achieved.

APOE ɛ4 dose associates with increased brain iron and ß-amyloid via blood-brain barrier dysfunction.

OBJECTIVE: To examine the effect of apolipoprotein E (APOE) ɛ4 dose on blood-brain barrier (BBB) clearance function, evaluated using an advanced MRI technique and analyse its correlation with brain iron and ß-amyloid accumulation in the early stages of the Alzheimer's continuum. METHODS: In this single-centre observational prospective cohort study, 24 APOE ɛ4 non-carriers, 22 heterozygotes and 20 homozygotes in the early stages of the Alzheimer's continuum were scanned with diffusion-prepared arterial spin labelling, which estimates the water exchange rate across the BBB (kw). Participants also underwent quantitative susceptibility mapping, [11C]Pittsburgh compound B-positron emission tomography and neuropsychological testing. Using an atlas-based approach, we compared the regional kw of the whole brain among the groups and analysed its correlation with the neuroradiological and neuropsychological findings. RESULTS: The BBB kw values in the neocortices differed significantly among the groups (APOE ɛ4 non-carriers>heterozygotes>homozygotes). These values correlated with brain iron levels (frontal lobe: r=-0.476, 95% CI=-0.644 to -0.264, p=0.011; medial temporal lobe: r=-0.455, 95% CI=-0.628 to -0.239, p=0.017), ß-amyloid loads (frontal lobe: r=-0.504, 95% CI=-0.731 to -0.176, p=0.015; medial temporal lobe: r=-0.452, 95% CI=-0.699 to -0.110, p=0.036) and neuropsychological scores, after adjusting for age, sex and APOE ɛ4 dose. INTERPRETATION: Our results suggest that an increased APOE ɛ4 dose is associated with decreased effective brain-waste clearance, such as iron and ß-amyloid, through the BBB.

Absence of diffusion-weighted imaging abnormalities in a patient with neuronal intranuclear inclusion disease.

INTRODUCTION: Herein, we report a genetically confirmed case of neuronal intranuclear inclusion disease without characteristic subcortical hyperintensities on diffusion-weighted imaging. CASE PRESENTATION: A 75-year-old man was admitted to our hospital with subacute onset of conscious disturbance. Except for gastric cancer, he had no apparent past medical or family history. He presented with transient fever, vomiting, and urinary retention. On admission, no apparent abnormal intensity was detected on diffusion-weighted imaging. The symptoms improved within 10 days, without any medical treatment. Additional inspections were performed under suspicion of neuronal intranuclear inclusion disease. Intranuclear inclusions were found not only from skin biopsy but also from his stomach specimens, which had been resected 6 years previously. Subsequent genetic testing revealed repeat expansion of GGC amplification in NOTCH2NLC. CONCLUSION: Characteristic neuroimaging and skin biopsy findings are important clues for diagnosing neuronal intranuclear inclusion diseases. Nonetheless, confirming a diagnosis is difficult due to the diversity of clinical manifestations and radiological features. Clinicians should suspect neuronal intranuclear inclusion disease in patients with transient encephalitic episodes, even if no abnormalities are detected on diffusion-weighted imaging.

A Case of Posterior Circulation Embolism Due to a Subtype of Bow Hunter's Syndrome Diagnosed by Non-Invasive Examination.

Bow hunter's syndrome is the mechanical compression of the vertebral artery due to cervical rotation, resulting in ischemic symptoms in the vertebrobasilar artery territory. However, some cases present without typical symptoms and exhibit compression of the non-dominant side of the vertebral artery. We encountered a case of posterior circulation embolism due to a subtype of bow hunter's syndrome in a 74-year-old man. Although the right vertebral artery was not visualized on time-of-flight magnetic resonance angiography in the neutral position, duplex ultrasonography and time-of-flight magnetic resonance angiography in the left cervical rotation position showed blood flow in the right vertebral artery. In this case, blood flow in the contralateral vertebral artery was normal, and typical bow hunter's syndrome symptoms did not occur. In a case of posterior circulation embolism with undetermined etiology, wherein the routine duplex ultrasonography and time-of-flight magnetic resonance angiography results were inconclusive, additional testing with head positioning led to the diagnosis of a subtype of bow hunter's syndrome.

Quantitative arterial spin labeling magnetic resonance imaging analysis of reversible cerebral vasoconstriction syndrome: A case series.

OBJECTIVE: This study aimed to quantify chronological cerebral blood flow (CBF) changes using arterial spin labeling (ASL) magnetic resonance imaging in patients with reversible cerebral vasoconstriction syndrome (RCVS). BACKGROUND: Quantitative ASL analyses in RCVS have not been well described in the literature. METHODS: Quantification of ASL using an automated region-of-interest placement software and a 5-point visual scale of vasoconstriction severity was performed in five RCVS patients. The association between CBF changes and RCVS-related complications was evaluated. RESULTS: Quantitative ASL revealed variable patterns of decreasing CBF in the first week, followed by subsequent increases. Notably, arterial vasoconstriction paradoxically progressed despite an increase in CBF from the first to the second week; this increase was relatively higher in patients with both cortical subarachnoid hemorrhage and posterior reversible encephalopathy syndrome. CONCLUSIONS: Quantitative ASL revealed that CBF initially decreased and subsequently increased, especially in the second week. These changes may serve as surrogate imaging markers for RCVS-related complications, and could further contribute to understanding the pathology of RCVS.

Magnetic Susceptibility Associates With Dopaminergic Deficits and Cognition in Parkinson's Disease.

OBJECTIVE: The objective of this study was to assess the relationship between nigrostriatal magnetic susceptibility and dopamine transporter abnormality and their associations with behavioral and cognitive impairments in patients with Parkinson's disease (PD). METHODS: For this case-control study, we enrolled 41 patients with PD and 20 age-matched healthy controls. All participants underwent global physical and cognitive assessments, 3-Tesla brain magnetic resonance imaging including quantitative susceptibility mapping (QSM; iron deposition measure), and 123 I-N-v-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl) nortropane single-photon emission computed tomography (dopamine transporter measure). We subdivided the striatum into the putamen, caudate nucleus, and nucleus accumbens and measured the nigrostriatal QSM values and dopamine transporter-specific binding ratios using an atlas-based approach. RESULTS: The patients with PD had higher QSM values in the substantia nigra and subdivisions of the striatum than did the healthy controls. The striatal dopamine transporter-specific binding ratios were not correlated with the QSM values of the substantia nigra but were inversely correlated with those of the striatum (putamen, r = -0.478, P = 0.009; caudate nucleus, r = -0.462, P = 0.011). The QSM values of the putamen were positively correlated with motor parkinsonism scores (Movement Disorder Society Unified Parkinson's Disease Rating Scale, r = 0.505, P = 0.003), and those of the caudate nucleus were negatively correlated with cognitive impairment scores (Montreal Cognitive Assessment, r = -0.525, P < 0.001). CONCLUSIONS: This study showed that striatal iron accumulations were correlated with dopaminergic deficits and neurophysiological signs in patients with PD, highlighting the potential of QSM as an auxiliary biomarker for parkinsonism and cognitive dysfunction. © 2020 International Parkinson and Movement Disorder Society.

Multiple Border-Zone Infarcts Triggered by Influenza A Virus Infection in a Patient With Cerebral Autosomal Dominant Arteriopathy Presenting With Subcortical Infarcts and Leukoencephalopathy.

Patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can develop multiple border-zone infarcts due to hypotension, hypovolemia, or surgery. We report the case of a 41-year-old woman with CADASIL who developed multiple border-zone infarcts due to influenza A virus infection. The patient had no apparent history or episode of stroke or altered consciousness following the onset of respiratory symptoms, which were due to the influenza A infection. Diffusion-weighted magnetic resonance images of the brain showed multiple acute-phase infarcts in border-zone areas of both cerebral hemispheres and the corpus callosum; fluid-attenuated inversion-recovery magnetic resonance images showed increased signal in the subcortical areas of both temporal poles. Gene analysis identified a heterozygous mutation c.160C>T in exon 2 of the NOTCH3 gene (p.Arg54Cys). A diagnosis of CADASIL was established. Our case demonstrates that infectious conditions such as influenza A can trigger multiple border-zone infarctions in patients with CADASIL.

Importance of Chronological Changes on High-Resolution Vessel Wall Imaging for Diagnosis of Isolated Anterior Cerebral Artery Dissection.

INTRODUCTION: The accurate diagnosis of isolated anterior cerebral artery dissection (iACA-D) is made difficult by the spatial resolution on conventional magnetic resonance imaging (MRI) techniques including time-of-flight magnetic resonance angiography that is too limited to detect minute arterial wall abnormalities. Recent advances in high-resolution vessel wall imaging (HRVWI), which can detect intramural hematomas (IMH), have improved the noninvasive diagnostic accuracy of iACA-D. However, despite the risk of overlooking minute IMH and aneurysmal dilations especially at the early disease stage, the utility of T1-weighted and T2-weighted HRVWI at each disease stage (i.e., acute, early subacute, late subacute and chronic) has not been evaluated thoroughly enough. This prompted us to undertake the present study to determine the diagnostic value of chronological changes of IMHs on T1-weighted HRVWI and arterial dilations on T2-weighted HRVWI to achieve the earliest possible and most accurate diagnosis of iACA-D. METHODS: In addition to six patients with iACA-D, five previously reported iACA-D patients from three institutions for whom reliable information on HRVWI and its examination date was available were enrolled in this study. IMHs on T1-weighted HRVWI and aneurysmal dilations on T2-weighted HRVWI and their chronological changes were visually evaluated. RESULTS: Either or both of IMHs on T1-weighted HRVWI and aneurysmal dilations on T2-weighted HRVWI were detected in all our six patients and the five previously reported ones. The disease stage showed a notable influence on the degree of their visualization. In contrast to IMHs which are regarded as the gold standard for the diagnosis of intracranial dissections, aneurysmal dilations were identified in 80% of cases even at the acute stage, reaching 100% at the early subacute stage. Despite the excellent detection rate of IMHs at the late subacute stage (100%), their detectability is poor at the acute and early subacute stages (0 and 40%, respectively). CONCLUSION: The results of this study highlighted the importance of aneurysmal dilations on T2-weighted HRVWI as a diagnostic marker to raise suspicion of iACA-D at the acute and early subacute stages, and similarly IMHs on T1-weighted HRVWI to confirm the diagnosis of iACA-D at the late subacute stage. These stage-dependent detectability changes in IMHs and aneurysmal dilations make an understanding of the chronological changes of these abnormal imaging findings mandatory to achieve an early and accurate diagnosis of iACA-D.

Voxel-based quantitative susceptibility mapping in Parkinson's disease with mild cognitive impairment.

OBJECTIVE: Brain iron accumulation has been proposed as one of the pathomechanisms in Parkinson's disease (PD). This study aimed to examine the whole-brain pattern of iron accumulation associated with cognitive impairment in patients with PD using voxel-based quantitative susceptibility mapping analysis. METHODS: We enrolled 24 patients with PD and mild cognitive impairment, 22 patients with PD and normal cognition, and 20 age-matched healthy controls in this cross-sectional study. All participants underwent global cognitive and physical assessments and brain MRI. Using a combined method of voxel-based morphometry and quantitative susceptibility mapping, we compared the voxel-wise magnetic susceptibility of the whole brain between the groups and analyzed its correlation with the cognitive and behavioral data. RESULTS: The PD and mild cognitive impairment group had lower Montreal Cognitive Assessment (MoCA) score than the PD and normal cognition and healthy control groups. There were no gray matter volumetric differences between the groups. In contrast, the voxel-based quantitative susceptibility mapping analysis showed that the PD and mild cognitive impairment group had significantly higher quantitative susceptibility mapping values in the cuneus, precuneus, caudate head, fusiform gyrus, and orbitofrontal cortex than did the PD and normal cognition group. These quantitative susceptibility mapping values were negatively correlated with the MoCA scores in the PD patients (cuneus: r = -0.510, P < .001; caudate head: r = -0.458, P = 0.002). CONCLUSIONS: This study suggests that cognitive impairment in PD is associated with cerebral iron burden and highlights the potential of quantitative susceptibility mapping as an auxiliary biomarker for early evaluation of cognitive decline in patients with PD. © 2019 International Parkinson and Movement Disorder Society.

Characteristic asymmetric limbic and anterior temporal atrophy in demented patients with pathologically confirmed argyrophilic grain disease.

PURPOSE: The purpose of this study is to clarify the characteristic structural magnetic resonance imaging (MRI) findings in demented patients with pathologically confirmed argyrophilic grain disease (AGD). METHODS: Nine pathologically confirmed AGD patients with cerebral three-dimensional T1-weighted MRI were evaluated in this study. In addition to visual rating scales of atrophic and asymmetric changes in the limbic and temporal lobes, voxel-based morphometry (VBM) was performed to assess group difference between pathologically confirmed AGD and Alzheimer's disease (AD) patients. RESULTS: On visual analyses of AGD patients, the medial temporal, anterior temporal, and posterior temporal atrophy scores were 3.3 ± 0.7, 1.7 ± 0.5, and 1.0 ± 0.7, respectively. Asymmetric scores of the hippocampus and parahippocampal gyrus, amygdala and ambient gyrus, anterior temporal, and posterior temporal lobes were rated as 1.1 ± 0.7, 1.6 ± 0.5, 1.3 ± 0.8, and 0.4 ± 0.7, respectively. In spite of no statistical differences in atrophic scores, AGD patients showed the higher score and proportion of anterior temporal asymmetric score than AD (p = 0.03 and 0.02). Compared with controls, VBM analysis revealed left dominant asymmetric atrophy predominantly in the limbic and anterior temporal lobe in AGD patients. By contrast, there was no significant gray matter reduction between AGD and AD patients. CONCLUSIONS: Asymmetric atrophy relatively localized to the anterior temporal and limbic lobes including the amygdala and ambient gyrus is a characteristic MRI finding of AGD. For the precise antemortem diagnosis, especially to differentiation from AD, it is important to pay attention to this asymmetric change.

Multifaceted structural magnetic resonance imaging findings in demented patients with pathologically confirmed TDP-43 proteinopathy.

This short report clarifies the heterogeneity of structural magnetic resonance imaging (MRI) findings in seven demented patients due to pathologically accumulated TAR DNA-binding protein-43 (TDP-43) protein using visual analyses including visual rating scales (i.e., global cortical atrophy and medial temporal atrophy scales). In addition to the well-known frontotemporal lobar atrophy, structural MRI has revealed multifaceted imaging findings including asymmetric atrophy of the frontoparietal lobe and cerebral peduncle, midbrain atrophy, and localized or diffuse white matter T2 hyperintensity. Understanding of these multifaceted neuroimaging findings is important for the precise antemortem diagnosis of TDP-43 proteinopathy.

Altered functional connectivity of the default mode network by glucose loading in young, healthy participants.

BACKGROUND: The functional connectivity of the default mode network (DMN) decreases in patients with Alzheimer's disease (AD) as well as in patients with type 2 diabetes mellitus (T2DM). Altered functional connectivity of the DMN is associated with cognitive impairment. T2DM is a known cause of cognitive dysfunction and dementia in the elderly, and studies have established that T2DM is a risk factor for AD. In addition, recent studies with positron emission tomography demonstrated that increased plasma glucose levels decrease neuronal activity, especially in the precuneus/posterior cingulate cortex (PC/PCC), which is the functional core of the DMN. These findings prompt the question of how increased plasma glucose levels decrease neuronal activity in the PC/PCC. Given the association among DMN, AD, and T2DM, we hypothesized that increased plasma glucose levels decrease the DMN functional connectivity, thus possibly reducing PC/PCC neuronal activity. We conducted this study to test this hypothesis. RESULTS: Twelve young, healthy participants without T2DM and insulin resistance were enrolled in this study. Each participant underwent resting-state functional magnetic resonance imaging in both fasting and glucose loading conditions to evaluate the DMN functional connectivity. The results showed that the DMN functional connectivity in the PC/PCC was significantly lower in the glucose loading condition than in the fasting condition (P = 0.014). CONCLUSIONS: Together with previous findings, the present results suggest that decreased functional connectivity of the DMN is possibly responsible for reduced PC/PCC neuronal activity in healthy individuals with increased plasma glucose levels.

Dinosaur Tail Sign: A Useful Spinal MRI Finding Indicative of Cerebrospinal Fluid Leakage.

OBJECTIVE: To evaluate the imaging characteristics and diagnostic utility of the "Dinosaur tail sign" in the diagnosis of cerebrospinal fluid (CSF) leakage. BACKGROUND: The authors propose the "Dinosaur tail sign," defined as a combination of the dorsal epidural hyperintensities, fat tissue, spinal cord, and cauda equine on lumbosacral sagittal fat-suppressed T2-weighted image (FST2WI), as a sensitive indicator for diagnosing CSF leakage. METHODS: Imaging characteristics of the "Dinosaur tail sign" was evaluated in seven spontaneous intracranial hypotension (SIH) and 23 iatrogenic CSF leakage (ICSFL) patients. Additionally, the diagnostic index was compared between the "Dinosaur tail sign" and other previously reported useful magnetic resonance imaging (MRI) and magnetic resonance myelography (MRM) findings. RESULTS: In contrast to other imaging findings including the epidural expansion, floating dural sac sign, and distension of the spinal epidural veins on MRI, and paraspinal fluid collections (PFC) on MRM, the "Dinosaur tail sign" was found equally in both SIH and ICSFL patients (6 SIH and 19 ICSFL; 83% of all patients with CSF leakage). The "Dinosaur tail sign" showed sufficient diagnostic utility (sensitivity 83%, specificity 94%, accuracy 89%) that was comparable to that of PFC. CONCLUSION: The "Dinosaur tail sign" is a useful imaging finding suggestive of CSF leakage. Evaluation of subtle interspinous arched hyperintensities on spinal MRI is mandatory for the diagnosis of SIH and ICSFL.

Beyond the midbrain atrophy: wide spectrum of structural MRI finding in cases of pathologically proven progressive supranuclear palsy.

PURPOSE: Recently, it has been recognized that pathologically proven progressive supranuclear palsy (PSP) cases are classified into various clinical subtypes with non-uniform symptoms and imaging findings. This article reviews essential imaging findings, general information, and advanced magnetic resonance imaging (MRI) techniques for PSP and presents these MRI findings of pathologically proven typical and atypical PSP cases for educational purposes. METHODS: With the review of literatures, notably including atypical pathologically proven PSP cases, MRI and clinical information of 15 pathologically proven typical and atypical PSP cases were retrospectively evaluated. RESULTS: In addition to typical symptoms, PSP patients can exhibit atypical symptoms including levodopa-responsive parkinsonism, pure akinesia, non-fluent aphasia, corticobasal syndrome, and predominant cerebellar ataxia. As well as clinical symptoms, the degree of midbrain atrophy, a well-known imaging hallmark, is not consistent in atypical PSP cases. This fact has important implications for the limitation of midbrain atrophy as a diagnostic imaging biomarker of PSP pathology. Additional evaluation of other imaging findings including various regional atrophies of the globus pallidus, frontal lobe, cerebral peduncle, and superior cerebellar peduncle is essential for the diagnosis of atypical PSP cases. CONCLUSION: It is necessary for radiologists to recognize the wide clinical and radiological spectra of typical and atypical PSP cases.

Utility of T1- and T2-Weighted High-Resolution Vessel Wall Imaging for the Diagnosis and Follow Up of Isolated Posterior Inferior Cerebellar Artery Dissection with Ischemic Stroke: Report of 4 Cases and Review of the Literature.

BACKGROUND: An accurate diagnosis of isolated posterior inferior cerebellar artery dissection (iPICA-D) is difficult due to the limitation of spatial resolution on conventional magnetic resonance imaging (MRI) techniques to detect subtle vessel wall abnormalities. The recent development of MRI techniques, including high-resolution vessel wall imaging (HRVWI), has resulted in the improved diagnostic accuracy and efficiency of iPICA-D. In fact, T1-weighted HRVWI, which can reveal intramural hematomas in the posterior inferior cerebellar artery (PICA), is useful for the diagnosis of iPICA-D. However, the utility of T2-weighted HRVWI has not been previously reported. The aim of this study was to investigate the diagnostic utility of T1- and T2-weighted HRVWI for the diagnosis of iPICA-D. METHODS: We retrospectively evaluated MRI findings including intramural hematomas, dilations, and chronological changes in 4 patients with iPICA-D admitted to our hospital and related facility from January 2015 to August 2016. In addition to T1-weighted HRVWI, T2-weighted HRVWI was performed on isovoxel three-dimensional (3D) fast spin-echo or 3D sampling perfection with application-optimized contrast using different flip-angle evolution. We also reviewed cases of nonhemorrhagic iPICA-D with ischemic onset in which the MRI findings were described. RESULTS: In all 4 patients, in addition to the intramural hematomas on T1-weighted HRVWI, T2-weighted HRVWI clearly showed the fusiform dilation of the external diameter of the PICA. T2-weighted HRVWI was more useful than other techniques, including T1-weighted HRVWI, for the evaluation of arterial shape changes. CONCLUSIONS: Like T1-weighted HRVWI, T2-weighted HRVWI is useful for the diagnosis and assessment of chronological changes in vessel wall abnormalities during the follow-up period.

Associations between computed tomography features of thymomas and their pathological classification.

Background Thymoma exhibits a range of histological and biological features and their imaging findings varies. Purpose To evaluate the associations between CT findings of thymomas and their classification according to the Masaoka staging system and World Health Organization (WHO) classification. Material and Methods Eighty-four patients with thymoma were evaluated. Comparisons between the CT findings of Masaoka stage I/II and III/IV lesions, and the WHO type A-B1 (low risk) and B2/B3 (high risk) lesions were performed. Results Stage III/IV thymomas (mean size, 60 mm) were significantly larger than stage I/II (45 mm) lesions and had more irregular shape and contour. Necrosis and calcification were observed in 16 (59%) and nine (33%) stage III/IV thymomas, and 16 (28%) and seven (12%) stage I/II lesions, respectively. Regarding the WHO classification, the high-risk thymomas displayed irregular shape and contour more often than low-risk lesions. There were significant differences between the patterns of mediastinal invasion seen in high- and low-risk groups; 21 (68%) vs. six (12%) lesions demonstrated mediastinal fat invasion, seven (23%) vs. two (4%) lesions exhibited great vessel invasion, five (16%) vs. 0 (0%) lesions displayed pericardial invasion, and 18 (58%) vs. 10 (20%) lesions invaded the lungs, respectively. Conclusion Masaoka stage III/IV thymomas were larger in size, had more irregular shape and contour, and exhibited necrosis and calcification more often than the stage I/II lesions. In the WHO classification, high-risk thymomas demonstrated more irregular shape and contour than low-risk thymomas.

Preoperative transarterial embolization using gelatin sponge for hypervascular bone and soft tissue tumors in the pelvis or extremities.

BACKGROUND: Preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors plays an important role in reducing intraoperative blood loss (IBL). PURPOSE: To evaluate the use of a gelatin sponge in preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors in the pelvis or extremities. MATERIAL AND METHODS: Thirty-seven patients (21 men, 16 women; median age, 61 years; age range, 23-79 years) underwent preoperative transcatheter arterial embolization between April 2004 and January 2015. Medical records and images were reviewed, and the technical success rate, clinical success rate, and complications were evaluated. Technical success was defined as a devascularization rate of 75% or higher, and clinical success was defined as intraoperative blood loss (IBL) <1500 mL in cases undergoing surgery within 3 days of transarterial embolization and <3000 mL in cases operated 4 or more days later. RESULTS: Tumor sizes were in the range of 2.0-13.0 cm (median, 5.0 cm). The devascularization rate was decreased by >75% at follow-up angiography in all cases, and the technical success rate was 100 % (37/37). The median IBL was 491 mL (range, 30-3800 mL), and the clinical success rate was 89% (33/37). The minor complication of local pain was observed in 13 out of 37 cases (35%) during or after embolization, but was controllable by an analgesic. CONCLUSION: Preoperative transarterial embolization using a gelatin sponge appears to be feasible and safe, and may contribute to decreasing IBL.