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Objective@#Chemical exchange-dependent saturation transfer (CEST) MRI is sensitive for detecting solid-like proteins and may detect changes in the levels of mobile proteins and peptides in tissues. The objective of this study was to evaluate the characteristics of chemical exchange proton pools using the CEST MRI technique in patients with dementia. @*Materials and Methods@#Our institutional review board approved this cross-sectional prospective study and informed consent was obtained from all participants. This study included 41 subjects (19 with dementia and 22 without dementia). Complete CEST data of the brain were obtained using a three-dimensional gradient and spin-echo sequence to map CEST indices, such as amide, amine, hydroxyl, and magnetization transfer ratio asymmetry (MTR asym) values, using six-pool Lorentzian fitting. Statistical analyses of CEST indices were performed to evaluate group comparisons, their correlations with gray matter volume (GMV) and Mini-Mental State Examination (MMSE) scores, and receiver operating characteristic (ROC) curves. @*Results@#Amine signals (0.029 for non-dementia, 0.046 for dementia, p = 0.011 at hippocampus) and MTR asym values at 3 ppm (0.748 for non-dementia, 1.138 for dementia, p = 0.022 at hippocampus), and 3.5 ppm (0.463 for non-dementia, 0.875 for dementia, p = 0.029 at hippocampus) were significantly higher in the dementia group than in the non-dementia group. Most CEST indices were not significantly correlated with GMV; however, except amide, most indices were significantly correlated with the MMSE scores. The classification power of most CEST indices was lower than that of GMV but adding one of the CEST indices in GMV improved the classification between the subject groups. The largest improvement was seen in the MTR asym values at 2 ppm in the anterior cingulate (area under the ROC curve = 0.981), with a sensitivity of 100 and a specificity of 90.91. @*Conclusion@#CEST MRI potentially allows noninvasive image alterations in the Alzheimer’s disease brain without injecting isotopes for monitoring different disease states and may provide a new imaging biomarker in the future.
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Acute necrotizing encephalopathy (ANE) is a rare but distinctive type of influenza-associated encephalopathy characterized by symmetric multiple lesions with an invariable thalamic involvement. Although the exact pathogenesis of ANE remains unclear, the most prevalent hypothesis is the “cytokine storm,” which results in blood-brain-barrier breakdown. We present the case of a 10-year-old boy with fulminant ANE confirmed with serial MRI studies, including diffusion-weighted imaging and susceptibility-weighted imaging. A comparison of these serial images demonstrated detailed and longitudinal changes in MRI findings during the clinical course corresponding to pathophysiological changes. Our case clarifies the pathogenesis of ANE brain lesions using serial imaging studies and suggests that early immunomodulatory therapy reduces brain damage.
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Objective@#Chemical exchange-dependent saturation transfer (CEST) MRI is sensitive for detecting solid-like proteins and may detect changes in the levels of mobile proteins and peptides in tissues. The objective of this study was to evaluate the characteristics of chemical exchange proton pools using the CEST MRI technique in patients with dementia. @*Materials and Methods@#Our institutional review board approved this cross-sectional prospective study and informed consent was obtained from all participants. This study included 41 subjects (19 with dementia and 22 without dementia). Complete CEST data of the brain were obtained using a three-dimensional gradient and spin-echo sequence to map CEST indices, such as amide, amine, hydroxyl, and magnetization transfer ratio asymmetry (MTR asym) values, using six-pool Lorentzian fitting. Statistical analyses of CEST indices were performed to evaluate group comparisons, their correlations with gray matter volume (GMV) and Mini-Mental State Examination (MMSE) scores, and receiver operating characteristic (ROC) curves. @*Results@#Amine signals (0.029 for non-dementia, 0.046 for dementia, p = 0.011 at hippocampus) and MTR asym values at 3 ppm (0.748 for non-dementia, 1.138 for dementia, p = 0.022 at hippocampus), and 3.5 ppm (0.463 for non-dementia, 0.875 for dementia, p = 0.029 at hippocampus) were significantly higher in the dementia group than in the non-dementia group. Most CEST indices were not significantly correlated with GMV; however, except amide, most indices were significantly correlated with the MMSE scores. The classification power of most CEST indices was lower than that of GMV but adding one of the CEST indices in GMV improved the classification between the subject groups. The largest improvement was seen in the MTR asym values at 2 ppm in the anterior cingulate (area under the ROC curve = 0.981), with a sensitivity of 100 and a specificity of 90.91. @*Conclusion@#CEST MRI potentially allows noninvasive image alterations in the Alzheimer’s disease brain without injecting isotopes for monitoring different disease states and may provide a new imaging biomarker in the future.
ABSTRACT
Acute necrotizing encephalopathy (ANE) is a rare but distinctive type of influenza-associated encephalopathy characterized by symmetric multiple lesions with an invariable thalamic involvement. Although the exact pathogenesis of ANE remains unclear, the most prevalent hypothesis is the “cytokine storm,” which results in blood-brain-barrier breakdown. We present the case of a 10-year-old boy with fulminant ANE confirmed with serial MRI studies, including diffusion-weighted imaging and susceptibility-weighted imaging. A comparison of these serial images demonstrated detailed and longitudinal changes in MRI findings during the clinical course corresponding to pathophysiological changes. Our case clarifies the pathogenesis of ANE brain lesions using serial imaging studies and suggests that early immunomodulatory therapy reduces brain damage.
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Purpose@#This study aimed to propose an effective end-to-end process in medical imaging using an independent task learning (ITL) algorithm and to evaluate its performance in maxillary sinusitis applications. @*Materials and Methods@#For the internal dataset, 2122 Waters’ view X-ray images, which included 1376 normal and 746 sinusitis images, were divided into training (n=1824) and test (n=298) datasets. For external validation, 700 images, including 379 normal and 321 sinusitis images, from three different institutions were evaluated. To develop the automatic diagnosis system algorithm, four processing steps were performed: 1) preprocessing for ITL, 2) facial patch detection, 3) maxillary sinusitis detection, and 4) a localization report with the sinusitis detector. @*Results@#The accuracy of facial patch detection, which was the first step in the end-to-end algorithm, was 100%, 100%, 99.5%, and 97.5% for the internal set and external validation sets #1, #2, and #3, respectively. The accuracy and area under the receiver operating characteristic curve (AUC) of maxillary sinusitis detection were 88.93% (0.89), 91.67% (0.90), 90.45% (0.86), and 85.13% (0.85) for the internal set and external validation sets #1, #2, and #3, respectively. The accuracy and AUC of the fully automatic sinusitis diagnosis system, including site localization, were 79.87% (0.80), 84.67% (0.82), 83.92% (0.82), and 73.85% (0.74) for the internal set and external validation sets #1, #2, and #3, respectively. @*Conclusion@#ITL application for maxillary sinusitis showed reasonable performance in internal and external validation tests, compared with applications used in previous studies.
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Objectives@#. This study was conducted to compare clinicopathologic and radiologic factors between benign and malignant thyroid nodules and to evaluate the diagnostic performance of shear wave elastography (SWE) combined with B-mode ultrasonography (US) in differentiating malignant from benign thyroid nodules. @*Methods@#. This retrospective study included 92 consecutive patients with 95 thyroid nodules examined on B-mode US and SWE before US-guided fine-needle aspiration biopsy or surgical excision. B-mode US findings (composition, echogenicity, margin, shape, and calcification) and SWE elasticity parameters (maximum [Emax], mean, minimum, and nodule-to-normal parenchymal ratio of elasticity) were reviewed and compared between benign and malignant thyroid nodules. The diagnostic performance of B-mode US and SWE for predicting malignant thyroid nodules was analyzed. The optimal cutoff values of elasticity parameters for identifying malignancy were determined. Diagnostic performance was compared between B-mode US only, SWE only, and the combination of B-mode US with SWE. @*Results@#. On multivariate logistic regression analysis, age (odds ratio [OR], 0.90; P=0.028), a taller-than-wide shape (OR, 11.3; P=0.040), the presence of calcifications (OR, 15.0; P=0.021), and Emax (OR, 1.22; P=0.021) were independent predictors of malignancy in thyroid nodules. The combined use of B-mode US findings and SWE yielded improvements in sensitivity, the positive predictive value, the negative predictive value, and accuracy compared with the use of B-mode US findings only, but with no statistical significance. @*Conclusion@#. When SWE was combined with B-mode US, the diagnostic performance was better than when only B-mode US was used, although the difference was not statistically significant.
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Although various neoplasms may develop in the ventricular system, glioblastomas are rare. An 80-year-old woman visited our hospital with intractable headache related to a right ventricular large mass, which exhibited heterogeneous enhancement involving the body, trigone, and occipital horn of the right lateral ventricle on MRI. The mass was diagnosed as glioblastoma multiforme on surgical pathology. Herein, the authors present a case and review the existing literature with regarding to incidence, pathophysiology, prognostic factors, imaging and pathologic findings of intraventricular glioblastoma multiforme.
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PURPOSE: Characteristic signs – the susceptibility vessel sign (SVS) and the prominent hypointense vessel sign (PHVS) – on T2*-based magnetic resonance imaging (T2*MRI) can be seen for acute ischemic stroke with large artery occlusion. In this study, we investigated the evidence to support our hypothesis that these findings may help to predict outcomes after reperfusion therapy. MATERIALS AND METHODS: We searched for papers describing SVS and PHVS in patients treated with reperfusion therapy for acute ischemic stroke, and their functional/radiologic outcomes were systematically reviewed. RESULTS: Nine studies on the SVS and six studies on the PHVS were included. The pooled odds ratio (OR) of recanalization after intravenous thrombolysis or mechanical thrombectomy was not significantly different with the presence of SVS (OR, 0.615; 95% confidence interval [CI], 0.335–1.131 and OR, 0.993; 95% CI, 0.629–1.567). The OR of favorable functional outcome after reperfusion therapy in terms of the presence of PHVS varied (0.083 to 1.831) by study. CONCLUSION: Our meta-analysis of the published data showed that a SVS was not a predictive factor for recanalization after reperfusion therapy for acute ischemic stroke. Currently, the data available on T2*MRI are too limited to warrant reperfusion therapy in routine practice. More data are needed from studies with randomized treatment allocation to determine the role of T2*MRI.
Subject(s)
Humans , Arteries , Magnetic Resonance Imaging , Odds Ratio , Reperfusion , Stroke , ThrombectomyABSTRACT
We report a case of dural arteriovenous fistula (DAVF) that showed spontaneous conversion of venous drainage pattern from Borden type II to type III within a four month period of follow-up. Upon admission, the patient presented with aggravated neurologic status and newly developed seizure. After admission, endovascular embolization was performed through the middle meningeal artery with Onyx®. Complete obliteration of dural arteriovenous shunt was confirmed by angiography, and the patient's clinical symptoms improved. Although most cases of DAVF show benign clinical course and conversion pattern, close follow-up is required to detect potential aggravation.
Subject(s)
Humans , Angiography , Central Nervous System Vascular Malformations , Drainage , Follow-Up Studies , Meningeal Arteries , SeizuresABSTRACT
Intracranial involvement in multiple myeloma patients takes up around 1%, and is usually known to be present in the parietal bone or skull base in cases of skull vault involvement, while it presents in the dura and parenchyma in cases of intracranial involvement. Primary pachymeningeal invasion is even rarer with extremely rapid progression and very poor prognosis. It is our intent to report a case in which we had to differentiate multiple myeloma with other metastatic tumors, lymphoma, and leukemia with intracranial involvement. Our patient showed an osteolytic lesion of the skull with dural involvement and subdural mass formations.
Subject(s)
Humans , Leukemia , Lymphoma , Multiple Myeloma , Parietal Bone , Prognosis , Skull , Skull BaseABSTRACT
BACKGROUND AND PURPOSE: The benefit of carotid endarterectomy (CEA) is directly influenced by the risk of perioperative adverse outcomes. However, patient-level risks and predictors including coronary stenosis are rarely evaluated, especially in Asian patients. The aim of this study was to determine the relationship between the vascular risk factors underlying CEA, including coronary stenosis, and postoperative outcome. METHODS: One hundred and fifty-three consecutive CEAs from our hospital records were included in this analysis. All patients underwent coronary computed tomography angiography before CEA. Data were analyzed to determine the vascular outcomes in patients with mild-to-moderate vs. severe coronary stenosis and high vs. standard operative risk, based on the criteria for high operative risk defined in the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial. The vascular outcome was defined as the occurrence of postoperative (< or =30 days) stroke, myocardial infarction (MI), or death. RESULTS: An adverse vascular outcome occurred in 8 of the 153 CEAs, with 6 strokes, 2 MIs, and 3 deaths. The vascular outcome differed significantly between the groups with mild-to-moderate and severe coronary stenosis (p=0.024), but not between the high- and standard-operative-risk groups (stratified according to operative risk as defined in the SAPPHIRE trial). Multivariable analysis adjusting for potent predictors revealed that severe coronary stenosis (odds ratio, 6.87; 95% confidence interval, 1.20-39.22) was a significant predictor of the early vascular outcome. CONCLUSIONS: Severe coronary stenosis was identified herein as an independent predictor of an adverse early vascular outcome.
Subject(s)
Humans , Aluminum Oxide , Angiography , Angioplasty , Asian People , Coronary Angiography , Coronary Artery Disease , Coronary Stenosis , Endarterectomy , Endarterectomy, Carotid , Hospital Records , Myocardial Infarction , Risk Assessment , Risk Factors , Stents , StrokeABSTRACT
We report perfusion weighted imaging (PWI) findings of nonenhanced anaplastic astrocytoma in a 30-year-old woman. Brain magnetic resonance imaging showed a nonenhanced brain tumor with mild peritumoral edema on the right medial frontal lobe and right genu of corpus callosum, suggesting a low-grade glioma. However, PWI showed increased relative cerebral blood volume, relative cerebral blood flow, and permeability of nonenhanced brain tumor compared with contralateral normal brain parenchyma, suggesting a high-grade glioma. After surgery, final histopathological analysis revealed World Health Organization grade III anaplastic astrocytoma. This case demonstrates the importance of PWI for preoperative evaluation of nonenhanced brain tumors.
Subject(s)
Adult , Female , Humans , Astrocytoma , Blood Volume , Brain , Brain Neoplasms , Corpus Callosum , Diagnosis , Edema , Frontal Lobe , Glioma , Magnetic Resonance Angiography , Magnetic Resonance Imaging , Perfusion , Permeability , World Health OrganizationABSTRACT
We report perfusion weighted imaging (PWI) findings of nonenhanced anaplastic astrocytoma in a 30-year-old woman. Brain magnetic resonance imaging showed a nonenhanced brain tumor with mild peritumoral edema on the right medial frontal lobe and right genu of corpus callosum, suggesting a low-grade glioma. However, PWI showed increased relative cerebral blood volume, relative cerebral blood flow, and permeability of nonenhanced brain tumor compared with contralateral normal brain parenchyma, suggesting a high-grade glioma. After surgery, final histopathological analysis revealed World Health Organization grade III anaplastic astrocytoma. This case demonstrates the importance of PWI for preoperative evaluation of nonenhanced brain tumors.
Subject(s)
Adult , Female , Humans , Astrocytoma , Blood Volume , Brain , Brain Neoplasms , Corpus Callosum , Diagnosis , Edema , Frontal Lobe , Glioma , Magnetic Resonance Angiography , Magnetic Resonance Imaging , Perfusion , Permeability , World Health OrganizationABSTRACT
Supratentorial hemangioblastomas (HBs) are rare, and pituitary stalk HBs are extremely uncommon; therefore, pituitary stalk evaluation is often overlooked. Herein, we report the development of pituitary stalk HB over a 20-year period and the importance of regular long-term follow up for patients with HBs.
Subject(s)
Humans , Follow-Up Studies , Hemangioblastoma , Pituitary Gland , von Hippel-Lindau DiseaseABSTRACT
Rhinocerebral mucormycosis is an acute fulminant opportunistic fungal infection usually seen in diabetic or immunocompromised patients. The fungi that cause mucormycosis inoculate the nasal mucosa and may spread to the paranasal sinuses, orbit, and brain. Our patient initially presented with mild ethmoid sinusitis. At that time, brain MRI and contrast-enhanced MR angiography were grossly normal. However, aggravation of sinusitis with extension to the right orbit and anterior cranial fossa rapidly developed within two months. Moreover, an occlusion of the right internal carotid artery was combined. We report a case of a pathologically-proven rhino-orbital-cerebral mucormycosis with serial follow-up imaging for over one year.
Subject(s)
Humans , Angiography , Brain , Carotid Artery, Internal , Cranial Fossa, Anterior , Ethmoid Sinus , Ethmoid Sinusitis , Follow-Up Studies , Fungi , Immunocompromised Host , Mucormycosis , Nasal Mucosa , Orbit , Paranasal Sinuses , SinusitisABSTRACT
We report magnetic resonance image (MRI) and magnetic resonance spectroscopy (MRS) findings in a patient of cerebral fat embolism (CFE) occurred in a 26-year-old woman after an autologous fat injection into the face. After initial neurologic symptom onset, MRI and MRS data were obtained two times to investigate repeated CFE. We obtained the MRS data in the two different time intervals and two different echo times to compare the lesions with normal brain parenchyma. The results of MRS data showed that a decrease in N-acetyl-aspartate, an increase in lactate and a very high early peak of free lipids between 0.9 and 1.4 ppm were obtained at the acute infarcted lesion as compared with normal brain parenchyma. In addition, these findings were more clearly detected on short echo time spectrum rather than long spectrum. A close relationship between the clinical manifestations and MRI and MRS findings of the brain can helpful to distinguish CFE with other conditions and to evaluate the cause materials of infarctions rather than conventional MRI or diffusion-weighted imaging.
Subject(s)
Adult , Female , Humans , Brain , Embolism, Fat , Infarction , Lactic Acid , Magnetic Resonance Spectroscopy , Magnetics , Magnets , Neurologic ManifestationsABSTRACT
PURPOSE: The objective of this study was to investigate the differences of hippocampal volume and shape as well as the functional change between long life experienced taxi drivers and controls of Korean population. MATERIALS AND METHODS: Three-dimensional T1-weighted images and blood oxygen level dependent functional MRI(fMRI) were obtained from 8 subjects, consisting of 4 experienced (20-30 years) taxi drivers and 4 age-matched controls. The hippocampal volume and shape were analyzed with three-dimensional T1-weighted images. In addition, neuronal activities of brain were analyzed using a blood oxygen level dependent fMRI between the two groups. RESULTS: The hippocampal volume showed no statistically significant difference between the two groups (p > 0.05). The left hippocampi of the taxi drivers were slightly elongated with larger head and tail portions than those of the controls (p < 0.05, uncorrected). For the functional MRI, fusiform gyrus was specifically activated in taxi drivers, compared with the control group. CONCLUSION: The structural and functional changes of taxi driver's hippocampus indicate the functional differentiation as a result of occupational dependence on spatial navigation. In other words, the continuous usage of spatial navigation performance may diminish degeneration of hippocampus and the related brain regions.
Subject(s)
Brain , Head , Hippocampus , Magnetic Resonance Imaging , Neurons , Orientation , OxygenABSTRACT
PURPOSE: The occurrence of a vascular perforation during an endovascular procedure is an unexpected and feared complication which can be fatal. However, the incidence, risk or the mechanism of vascular perforation which can occur in the endovascular management of aneurysms remains unclear. The purpose of the present study was to evaluate the incidence of vascular perforation during endovascular coil embolization of a cerebral aneurysm, and to reveal characteristics and clinical outcomes. MATERIALS AND METHODS: We reviewed the endovascular coil embolization procedures performed for the treatment of 459 aneurysms. Incidence and clinical, radiological and technical data of patients concerning the vascular perforation were reviewed from medical records and radiological findings. RESULTS: The incidence of procedure-related vascular perforation in our patient group was 0.87% (4/459). For all four occurrences, the cause of vascular perforation involved the guidewire or microcatheter. Clinical outcome was poor in 2 cases and favorable in 2 cases. CONCLUSION: Although rare, the occurrence of vascular perforation during coil embolization for treatment of an aneurysm may be fatal. Therefore, careful management of the guidewire is suggested for the prevention of vascular rupture during an endovascular procedure.