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Dive into the research topics where Carlos A. Zamora is active.

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Featured researches published by Carlos A. Zamora.


European Radiology | 2006

Endovascular obliteration of bleeding duodenal varices in patients with liver cirrhosis

Carlos A. Zamora; Koji Sugimoto; Masakatsu Tsurusaki; Kenta Izaki; Tetsuya Fukuda; Shinichi Matsumoto; Yoichiro Kuwata; Ryota Kawasaki; Takanori Taniguchi; Shozo Hirota; Kazuro Sugimura

The purpose of this paper is to describe our experience with endovascular obliteration of duodenal varices in patients with liver cirrhosis and portal hypertension. Balloon-occluded transvenous retrograde and percutaneous transhepatic anterograde embolizations were performed for duodenal varices in five patients with liver cirrhosis, portal hypertension, and decreased liver function. All patients had undergone previous endoscopic treatments that failed to stop bleeding and were poor surgical candidates. Temporary balloon occlusion catheters were used to achieve accumulation of an ethanolamine oleate–iopamidol mixture inside the varices. Elimination of the varices was successful in all patients. Retrograde transvenous obliteration via efferent veins to the inferior vena cava was enough to achieve adequate sclerosant accumulation in three patients. A combined anterograde–retrograde embolization was used in one patient with balloon occlusion of afferent and efferent veins. Transhepatic embolization through the afferent vein was performed in one patient under balloon occlusion of both efferent and afferent veins. There was complete variceal thrombosis and no bleeding was observed at follow-up. No major complications were recorded. Endovascular obliteration of duodenal varices is a feasible and safe alternative procedure for managing patients with portal hypertension and hemorrhage from this source.


CardioVascular and Interventional Radiology | 2004

Renal arteriovenous fistula with rapid blood flow successfully treated by transcatheter arterial embolization: application of interlocking detachable coil as coil anchor.

Takeki Mori; Koji Sugimoto; Takanori Taniguchi; Masakatsu Tsurusaki; Kenta Izaki; Junya Konishi; Carlos A. Zamora; Kazuro Sugimura

A 70-year-old woman presented to our outpatient clinic with a large idiopathic renal arteriovenous fistula (AVF). Transcatheter arterial embolization (TAE) using interlocking detachable coils (IDC) as an anchor was planned. However, because of markedly rapid blood flow and excessive coil flexibility, detaching an IDC carried a high risk of migration. Therefore, we first coiled multiple loops of a microcatheter and then loaded it with an IDC. In this way, the coil was well fitted to the arterial wall and could be detached by withdrawing the microcatheter during balloon occlusion (“pre-framing technique”). Complete occlusion of the afferent artery was achieved by additional coiling and absolute ethanol. This technique contributed to a safe embolization of a high-flow AVF, avoiding migration of the IDC.


Journal of Neurosurgery | 2015

Pediatric skull fracture diagnosis: should 3D CT reconstructions be added as routine imaging?

Gunes Orman; Matthias W. Wagner; Daniel Seeburg; Carlos A. Zamora; Alexander Oshmyansky; Aylin Tekes; Andrea Poretti; George I. Jallo; Thierry A.G.M. Huisman; Thangamadhan Bosemani

OBJECT The authors compared the efficacy of combining 2D+3D CT reconstructions with standard 2D CT images in the diagnosis of linear skull fractures in children with head trauma. METHODS This was a retrospective evaluation of consecutive head CT studies of children presenting with head trauma. Two experienced pediatric neuroradiologists in consensus created the standard of reference. Three readers independently evaluated the 2D CT images alone and then in combination with the 3D reconstructions for the diagnosis of linear skull fractures. Sensitivity and specificity in the diagnosis of linear skull fractures utilizing 2D and 2D+3D CT in combination were measured for children less than 2 years of age and for all children for analysis by the 3 readers. RESULTS Included in the study were 250 consecutive CT studies of 250 patients (167 boys and 83 girls). The mean age of the children was 7.82 years (range 4 days to 17.4 years). 2D+3D CT combined had a higher sensitivity and specificity (83.9% and 97.1%, respectively) compared with 2D alone (78.2% and 92.8%, respectively) with statistical significance for specificity (p < 0.05) in children less than 2 years of age. 2D+3D CT combined had a higher sensitivity and specificity (81.3% and 90.5%, respectively) compared with 2D alone (74.5% and 89.1%, respectively) with statistical significance for sensitivity (p < 0.05) in all children. CONCLUSIONS In this study, 2D+3D CT in combination showed increased sensitivity in the diagnosis of linear skull fractures in all children and increased specificity in children less than 2 years of age. In children less than 2 years of age, added confidence in the interpretation of fractures by distinguishing them from sutures may have a significant implication in the setting of nonaccidental trauma. Furthermore, 3D CT is available at no added cost, scan time, or radiation exposure, providing trainees and clinicians with limited experience an additional valuable tool for routine imaging of pediatric head trauma.


Brain and behavior | 2015

Delayed posthypoxic leukoencephalopathy: a case series and review of the literature.

Carlos A. Zamora; David Nauen; Robert Hynecek; Ahmet Turan Ilica; Izlem Izbudak; Haris I. Sair; Sachin K. Gujar; Jay J. Pillai

Delayed posthypoxic leukoencephalopathy (DPHL) is a rare and underrecognized entity where patients manifest a neurological relapse after initial recovery from an acute hypoxic episode. We sought to describe the magnetic resonance imaging (MRI) findings in a group of patients with DPHL and review the available literature.


Magnetic Resonance Imaging | 2008

Abdominal apparent diffusion coefficient measurements: effect of diffusion-weighted image quality and usefulness of anisotropic images

Takeshi Yoshikawa; Yoshiharu Ohno; Hideaki Kawamitsu; Yonson Ku; Yasushi Seo; Carlos A. Zamora; Nobukazu Aoyama; Kazuro Sugimura

This study aimed to assess the effect of diffusion-weighted image (DWI) quality on abdominal apparent diffusion coefficient (ADC) measurements and the usefulness of anisotropic images. Twenty-six patients (10 men and 16 women; mean, 58.1 years) who underwent DW imaging and were diagnosed not to have any abdominal diseases were analyzed. Single-shot spin-echo echo-planar DW imaging was performed, and one isotropic and three orthogonal anisotropic images were created. ADCs were calculated for liver (four segments), spleen, pancreas (head, body, tail) and renal parenchyma. Image quality for each organ part was scored visually. We estimated the correlation between ADC and image quality and evaluated the feasibility of using anisotropic images. ADCs and image quality were affected by motion probing gradient directions in the liver and pancreas. A significant inverse correlation was found between ADC and image quality. The r values for isotropic images were -.46, -.48, -.70 and -.28 for the liver, spleen, pancreas and renal parenchyma, respectively. Anisotropic images had the best quality and lowest ADC in at least one organ part in 17 patients. DWIs with the best quality among isotropic and anisotropic images should be used in the liver and pancreas.


Journal of Endovascular Therapy | 2004

Prophylactic Stenting of the Inferior Vena Cava before Transcatheter Embolization of Renal Cell Carcinomas: An Alternative to Filter Placement

Carlos A. Zamora; Koji Sugimoto; Takeki Mori; Takanori Taniguchi; Masakatsu Tsurusaki; Kenta Izaki; Masato Yamaguchi; Kazuro Sugimura

PURPOSE To report the use of the self-expanding Wallstent as an alternative to prophylactic inferior vena cava (IVC) filter placement before embolization of renal carcinomas with tumor thrombus. CASE REPORTS Two patients, a 71-year-old man and an 88-year-old woman, were diagnosed with extensive tumor infiltration of the IVC secondary to renal cell carcinomas. Prophylactic placement of an IVC filter before transcatheter embolization was unsuccessful in both cases; a reduced space for deployment would have left part of the filter inside the right atrium. Instead, a Wallstent was used to constrain the tumor thrombus against the vessel wall and, at the same time, protect the patency of the contralateral kidney. Adequate patencies were confirmed 9 months after stenting in the first patient and after 19 days in the second patient. There were no clinical manifestations of pulmonary embolism. CONCLUSIONS Wallstent implantation is an alternative prophylactic measure before transarterial embolization of renal carcinomas if IVC filters cannot be placed.


CardioVascular and Interventional Radiology | 2006

Transcatheter Embolization of Splenic Artery Pseudo-Aneurysm Rupturing into Colon After Post-Operative Pancreatitis

Yuki Iwama; Koji Sugimoto; Carlos A. Zamora; Masato Yamaguchi; Masakatsu Tsurusaki; Takanori Taniguchi; Takeki Mori; Kazuro Sugimura

Splenic pseudoaneurysms following chronic pancreatitis can rarely become a source of life-threatening bleeding by rupturing into various regions or components, including pseudocysts, the abdominal cavity, the gastrointestinal tract, and the pancreatic duct. In such cases, prompt diagnosis and therapy are warranted. We report herein the case of a 52-year-old man in whom a splenic pseudoaneurysm ruptured into the colon via a fistula with an abscess cavity, causing massive bleeding, which was successfully managed by trans-catheter arterial embolization (TAE).


Journal of Endovascular Therapy | 2005

Stent-grafting of an infected aortoesophageal fistula following ingestion of a fish bone.

Carlos A. Zamora; Koji Sugimoto; Yoshihiko Tsuji; Masamichi Matsumori; Takanori Taniguchi; Kazuro Sugimura; Yutaka Okita

The authors have no commercial, proprietary, or financial interest in any products or companies described in this article. However, many heparin limitations may be overcome with this alternative anticoagulant, including avoidance of intraoperative drug level monitoring. The safety profile of bivalirudin, with a trend toward lower bleeding complications and clinical efficacy equal to heparin with a GP IIb/IIIa inhibitor, makes bivalirudin a logical option for peripheral vascular interventions. Our experience with bivalirudin supports its use in either symptomatic or asymptomatic patients undergoing CAS with neuroprotection.


Radiation Medicine | 2006

Percutaneous balloon fenestration and stent placement for lower limb ischemia complicated with type B aortic dissection

Masato Yamaguchi; Koji Sugimoto; Yoshihiko Tsuji; Nobuchika Ozaki; Masakatsu Tsurusaki; Takanori Taniguchi; Carlos A. Zamora; Yutaka Okita; Kazuro Sugimura

We report a case of lower limb ischemia secondary to type B aortic dissection, which was successfully treated with endovascular aortic fenestration and stent placement. In this case, we were not able to restore adequate flow to the ischemic limb by means of aortic balloon fenestration alone, so additional stent placement was required to buttress the true lumen and fenestra. There was no recurrence of lower limb ischemia complications during the follow-up period. Aortic balloon fenestration with stent placement seems to be a safe and effective technique to salvage an ischemic lower limb complicated by acute aortic dissection.


Journal of Vascular and Interventional Radiology | 2006

Placement of Self-expanding Stents with Different Diameters in the Porcine Venous System: An Experimental Study

Masato Yamaguchi; Koji Sugimoto; Carlos A. Zamora; Takuya Takahashi; Yoshitake Hayashi; Kazuro Sugimura

PURPOSE To study the vascular histologic response after placement of oversized self-expanding stents in the porcine venous system. MATERIALS AND METHODS Twenty-four oversized stents (range of oversizing, 119.5%-216.0%) were deployed in jugular and iliac veins of six miniature pigs divided into two groups with follow-up times of 1 and 3 months. Necropsy with histologic evaluation of each stent was performed, and the areas of neointimal proliferation were calculated with slices obtained during follow-up from each stent at 5 mm from the proximal and distal edges and at the midpoint. RESULTS Neointimal proliferation was observed inside the stent lumen. All segments were patent in both groups. However, one jugular stent in the 1-month group and one jugular stent in the 3-month group had migrated at follow-up and were excluded from analysis. There were no significant differences in neointimal growth between the stent edges (proximal and distal) and middle segments of the stents at follow-up in the 1-month group (P = .970) or in the 3-month group (P = .694). Simple linear regression showed strong positive correlation between stent oversizing and neointimal proliferation in the 1-month model (r = 0.791; P < .001) and the 3-month model (r = 0.718; P < .001). There were no significant differences between 1-month and 3-month groups in the degree of neointimal proliferation (P = .072). Also, branched vessels showed no neointimal proliferation at their intersections with the stent-implanted segments. CONCLUSION Stent oversizing showed a strong positive correlation with neointimal growth in each follow-up model in this study.

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Mauricio Castillo

University of North Carolina at Chapel Hill

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Marinos Kontzialis

Rush University Medical Center

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