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Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment

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World Journal of Radiology 2016年第3期8卷 298-307页

作者： Maythem Saeed Roland Krug Loi Do steven W hetts Mark W Wilson Department of Radiology and Biomedical Imaging School of Medicine University of California San Francisco

AIM: To use magnetic resonance-guided high intensity focused ultrasound(MRg-HIFU), magnetic resonance imaging(MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue. METHODS: Six anesthetized/mechanically-ventilated pigs underwent single/double renal sonication(n = 24) using a 3T-MRg-HIFU(1.1 MHz frequency and 3000J-4400 J energies). T2-weighted fast spin echo(T2-W), perfusion saturation recovery gradient echo and contrast enhanced(CE) T1-weighted(T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student's t-test was used and a P-value < 0.05 was considered statistically ***: Ablated renal parenchyma could not be differentiated from normal parenchyma on T2-W or nonCE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images invivo(0.12-0.36 cm3 for single sonication 3000 J, 0.50-0.84 cm3, for double 3000 J, 0.75-0.78 cm3 for single 4400 J and 0.12-2.65 cm3 for double 4400J) and at postmortem(0.23-0.52 cm3, 0.25-0.82 cm3, 0.45-0.68 cm3 and 0.29-1.80 cm3, respectively) were comparable. The ablated volumes on 3000 J and 4400 J double sonication were significantly larger than single(P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, ***: Contrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI.

关键词： Magnetic resonance-guided high intensity focused ultrasound Renal ablation Magnetic resonance imaging Microscopy High intensity focused ultrasound

Magnetic resonance imaging and multi-detector computed tomography assessment of extracellular compartment in ischemic and non-ischemic myocardial pathologies

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World Journal of Cardiology 2014年第11期6卷 1192-1208页

作者： Maythem Saeed steven W hetts Robert Jablonowski Mark W Wilson Department of Radiology and Biomedical Imaging School of Medicine University of California San Francisco San Francisco CA 94107-5705 United States

Myocardial pathologies are major causes of morbidity and mortality worldwide. Early detection of loss of cellular integrity and expansion in extracellular volume(ECV) in myocardium is critical to initiate effective treatment. The three compartments in healthy myocardium are: intravascular(approximately 10% of tissue volume), interstitium(approximately 15%) and intracellular(approximately 75%). Myocardial cells, fibroblasts and vascular endothelial/smooth muscle cells represent intracellular compartment and the main proteins in the interstitium are types Ⅰ/Ⅲ collagens. Microscopic studies have shown that expansion of ECV is an important feature of diffuse physiologic fibrosis(e.g., aging and obesity) and pathologic fibrosis [heart failure, aortic valve disease, hypertrophic cardiomyopathy, myocarditis, dilated cardiomyopathy, amyloidosis, congenital heart disease, aortic stenosis, restrictive cardiomyopathy(hypereosinophilic and idiopathic types), arrythmogenic right ventricular dysplasia and hypertension]. This review addresses recent advances in measuring of ECV in ischemic and non-ischemic myocardial pathologies. Magnetic resonance imaging(MRI) has the ability to characterize tissue proton relaxation times(T1, T2, and T2*). Proton relaxation times reflect the physical and chemical environments of water protons in myocardium. Delayed contrast enhanced-MRI(DE-MRI) and multi-detector computed tomography(DE-MDCT) demonstrated hyper-enhanced infarct, hypo-enhanced microvascular obstruction zone and moderately enhanced peri-infarct zone, but are limited for visualizing diffuse fibrosis and patchy microinfarct despite the increase in ECV. ECV can be measured on equilibrium contrast enhanced MRI/MDCT and MRI longitudinal relaxation time mapping. Equilibrium contrast enhanced MRI/MDCT and MRI T1 mapping is currently used, but at a lower scale, as an alternative to invasive sub-endomyocardial biopsies to eliminate the need for anesthesia, coronary catheterization and possib

关键词： relaxation detecting compartment eliminate myocarditis cardiomyopathy myocardium infarct tomographic intravascular

Magnetic resonance imaging characterization of circumferential and longitudinal strain under various coronary interventions in swine

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World Journal of Radiology 2013年第12期5卷 472-483页

作者： Mohammed SA Suhail Mark W Wilson steven W hetts Maythem Saeed Department of Radiology and Biomedical Imaging School of Medicine University of California San Francisco School of Medicine University of California San Diego

AIM:To compare the acute changes in circumferential and longitudinal strain after exposing a coronary artery to various interventions in ***:Percutaneous balloon angioplasty catheter was guided to location aid device(LAD)under X-ray fluoroscopy to create different patterns of ischemic ***(n=32)were equally divided into 4 groups:controls,90 min LAD occlusion/reperfusion,LAD microembolization,and combined LAD occlusion/microembolization/*** days after interventions,cine,tagged and viability magnetic resonance imaging(MRI)were acquired to measure and compare left and right circumferential strain,longitudinal strain and myocardial viability,*** were obtained using HARP and semi-automated threshold method and statistically analyzed using unpaired *** and vascular damage was characterized ***:Coronary microemboli caused greater impairment in l left ventricular(LV)circumferential strain and dyssynchrony than LAD occlusion/reperfusion despite the significant difference in the extent of myocardial *** also caused significant decrease in peak systolic strain rate of remote myocardium and LV *** MRI demonstrated the interaction between LV and right ventricular(RV)at 3 d after *** increase in RV free wall longitudinal strain was seen in response to all *** MRI,histochemical staining and microscopy revealed different patterns of myocardial damage and microvascular ***:Cine MRI revealed subtle changes in LV strain caused by various ischemic *** also demonstrated the interaction between the right and left ventricles after coronary *** microemboli with and without acute myocardial infarction(AMI)cause complex myocardial injury and ventricular dysfunction that is not replicated in solely AMI.

关键词： Magnetic resonance imaging Percutaneous coronary interventions Acute myocardial infarct Microembolization Myocardial strain

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID- 19 pandemic

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Stroke & Vascular Neurology 2021年第4期6卷 542-552,I0026-I0032页

作者： Thanh N Nguyen Diogo C Haussen Muhammad M Qureshi Hiroshi Yamagami Toshiyuki Fujinaka Ossama Y Mansour Mohamad Abdalkader Michael Frankel Zhongming Qiu Allan Taylor Pedro Lylyk Omer F Eker Laura Mechtouff Michel Piotin Fabricio Oliveira Lima Francisco Mont'Alverne Wazim Izzath Nobuyuki Sakai Mahmoud Mohammaden Alhamza R Al-Bayati Leonardo Renieri Salvatore Mangiafico David Ozretic Vanessa Chalumeau Saima Ahmad Umair Rashid Syed Irteza Hussain Seby John Emma Griffin John Thornton Jose Antonio Fiorot Rodrigo Rivera Nadia Hammami Anna M Cervantes-Arslanian Hormuzdiyar H Dasenbrock Huynh Le Vu Viet Quy Nguyen steven hetts Romain Bourcier Romain Guile Melanie Walker Malveeka Sharma Don Frei Pascal Jabbour Nabeel Herial Fawaz Al-Mufti Atilla Ozcan Ozdemir Ozlem Aykac Dheeraj Gandhi Chandril Chugh Charles Matouk Pascale Lavoie Randall Edgell Andre Beer-Furlan Michael Chen Monika Killer-Oberpfalzer Vitor Mendes Pereira Patrick Nicholson Vikram Huded Nobuyuki Ohara Daisuke Watanabe Dong Hun Shin Pedro SC Magalhaes Raghid Kikano Santiago Ortega-Gutierrez Mudassir Farooqui Amal Abou-Hamden Tatsuo Amano Ryoo Yamamoto Adrienne Weeks Elena A Cora Rotem Sivan-Hoffmann Roberto Crosa Markus Möhlenbruch Simon Nagel Hosam Al-Jehani Sunil A Sheth Victor S Lopez Rivera James E Siegler Achmad Fidaus Sani Ajit S Puri Anna Luisa Kuhn Gianmarco Bernava Paolo Machi Daniel G Abud Octavio M Pontes-Neto Ajay K Wakhloo Barbara Voetsch Eytan Raz Shadi Yaghi Brijesh P Mehta Naoto Kimura Mamoru Murakami Jin Soo Lee Ji Man Hong Robert Fahed Gregory Walker Eiji Hagashi Steve M Cordina Hong Gee Roh Ken Wong Juan F Arenillas Mario Martinez-Galdamez Jordi Blasco Alejandro Rodriguez Vasquez Luisa Fonseca M Luis Silva Teddy Y Wu Simon John Alex Brehm Marios Psychogios William J Mack Matthew Tenser Tatemi Todaka Miki Fujimura Roberta Novakovic Jun Deguchi Yuri Sugiura Hiroshi Tokimura Rakesh Khatri Michael Kelly Lissa Peeling Yuichi Murayama Hugh Stephen Winters Johnny Wong Mohamed Teleb Jeremy Payne Hiroki Fukuda Kosuke Miyake Junsuke Shimbo Yusuke Sug Neurology RadiologyBoston Medical CenterBostonMassachusettsUSA Neurology Marcus Stroke&Neuroscience CenterGrady Memorial HospitalEmory University School of MedicineAtlantaGAUSA Radiology Radiation OncologyBoston University School of MedicineBostonMassachusettsUSA Neurology National Hospital Organization Osaka National HospitalOsakaJapan Neurosurgery National Hospital Organization Osaka National HospitalOsakaJapan Neurology Alexandria UniversityAlexandriaEgypt Radiology Boston Medical CenterBostonMassachusettsUSA Department of Neurology Xinqiao HospitalChongqingChina Neurosurgery University of Cape TownRondeboschWestern CapeSouth Africa Neurosurgery Interventional NeuroradiologyClinica La Sagrada FamiliaBuenos AiresArgentina Neuroradiologie Neurologie VasculaireHospices Civils de LyonLyonAuvergne-Rhône AlpesFrance Neurologie Vasculaire Hospices Civils de LyonLyonAuvergne-Rhône AlpesFrance Interventional Neuroradiology Fondation Ophtalmologique Adolphe de RothschildParisÎle-de FranceFrance Neurology Hospital Geral de FortalezaFortalezaBrazil Interventional Neuroradiology Hospital Geral de FortalezaFortalezaBrazil Neuroradiology Nottingham University Hospitals NHS TrustNottinghamUK Department of Neurosurgery Kobe City Medical Center General HospitalKobeHyogoJapan Interventional Neurovascular Unit University Hospital CareggiFirenzeToscanaItaly Neuroradiology University Hospital Centre ZagrebZagrebCroatia Interventional Neuroradiology Hopital BicetreLe Kremlin-BicetreFrance Stroke and Interventional Neuroradiology Lahore General HospitalLahorePakistan Neurological Institute Cleveland Clinic Abu DhabiAbu DhabiUAE Department of Radiology Beaumont HospitalDublinIreland Neurology Stroke UnitHospital-Estadual CentralVitoriaBrazil Neuroradiology Instituto de Neurocirugia Dr AsengoSantiagoChile Interventional Neuroradiology Institut National de NeurologieTunisTunisia Neurology Boston Medical CenterBostonMassachusettsUSA Neurosurgery Boston Medical Center

Background During the COVID-19 pandemic,decreased volumes of stroke admissions and mechanical thrombectomy were *** study’s objective was to examine whether subarachnoid haemorrhage(SAH)hospitalisations and ruptured aneurysm coiling interventions demonstrated similar *** We conducted a cross-sectional,retrospective,observational study across 6 continents,37 countries and 140 comprehensive stroke *** with the diagnosis of SAH,aneurysmal SAH,ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases,10th Revision,*** 3-month cumulative volume,monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before(1 year and immediately before)and during the pandemic,defined as 1 March-31 May *** prior 1-year control period(1 March-31 May 2019)was obtained to account for seasonal *** There was a significant decline in SAH hospitalisations,with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic,representing a relative decline of 22.5%(95%CI−24.3%to−20.7%,p<0.0001).Embolisation of ruptured aneurysms declined with 1170-1035 procedures,respectively,representing an 11.5%(95%CI−13.5%to−9.8%,p=0.002)relative *** analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations,a 24.9%relative decline(95%CI−28.0%to−22.1%,p<0.0001).A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1%(95%CI 32.3%to 50.6%,p=0.008)despite a decrease in SAH admissions in this *** There was a relative decrease in the volume of SAH hospitalisations,aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 *** findings in SAH are consistent with a decrease in other emergencies,such as stroke and myocardial infarction.

关键词： diagnosis representing subarachnoid