Publications by authors named "Dean A Nakamoto"

In-gantry MRI-guided biopsy (MRGB) of the prostate has been shown to be more accurate than other targeted prostate biopsy methods. However, the optimal number of cores to obtain during in-gantry MRGB remains undetermined. The purpose of this study was to assess the diagnostic yield of obtaining an incremental number of cores from the primary lesion and of second lesion sampling during in-gantry MRGB of the prostate.

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Since its introduction, contrast-enhanced ultrasound (CEUS) has gained an important role in the diagnosis and management of abdominal and pelvic diseases. Contrast-enhanced ultrasound can improve lesion detection rates as well as success rates of interventional procedures when compared to conventional ultrasound alone. Additionally, CEUS enables the interventionalist to assess the dynamic enhancement of different tissues and lesions, without the adverse effects of contrast-enhanced computed tomography, such as exposure to ionizing radiation and nephrotoxicity from iodinated contrast material.

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Ultrasound (US) represents the initial modality in the workup of abdominal aortic pathology based on the plethora of advantages including widespread availability, low cost, safety profile and repeatability. However, US has inherent limitations including limited spatial information of pathologic processes to neighboring structures, lower sensitivity to slow blood flow and aortic luminal irregularities. For evaluation of aortic pathology angiography has long been considered the gold standard.

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Background: To assess the technical success of contrast enhanced ultrasound (CEUS) guided biopsies of liver lesions poorly visualized on B-mode ultrasound.

Methods: Patients were selected during the procedure based on the real-time clinical scenario of unsatisfactory B-mode ultrasound lesion visualization and all patients would have otherwise undergone CT guided liver lesion biopsy. A total of 26 patients underwent CEUS guided biopsy and were included in this retrospective analysis.

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Purpose This manuscript describes the technique of real-time MRI-guided sclerotherapy for low-flow venous malformations in the head and neck based on our institutional experience. Materials and methods Ethanolamine oleate is used as the sclerosant and is mixed with gadolinium for visualization during the procedure. The five procedural steps include: (I) an initial tri-plane T2-weighted sequence to visualize the lesion; (II) a T1 FSE or trueFISP sequence to assess needle placement and advancement within the lesion; (III) a tri-plane T1 FLASH sequence to monitor sclerosant injection; (IV) a T1 FSE or VIBE sequence to assess sclerosant coverage of the malformation before needle removal; (V) a post-procedural tri-plane T1 fat-saturated sequence to confirm sclerosant coverage of the lesion.

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Real-time MRI-guided percutaneous sclerotherapy is a novel and evolving treatment for congenital lymphatic malformations in the head and neck. We elaborate on the specific steps necessary to perform an MRI-guided percutaneous sclerotherapy of lymphatic malformations including pre-procedure patient work-up and preparation, stepwise intraprocedural interventional techniques and post-procedure management. Based on our institutional experience, MRI-guided sclerotherapy with a doxycycline-gadolinium-based mixture as a sclerosant for lymphatic malformations of the head and neck region in children is well tolerated and effective.

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Preprocedural evaluation of patients in an interventional radiology (IR) clinic is a complex synthesis of physical examination and imaging findings, and as IR transitions to an independent clinical specialty, such evaluations will become an increasingly critical component of a successful IR practice and quality patient care. Prior research suggests that preprocedural evaluations increased patient's perceived quality of care and may improve procedural technical success rates. Appropriate documentation of a preprocedural evaluation in the medical record is also paramount for an interventional radiologist to add value and function as an effective member of a larger IR service and multidisciplinary health care team.

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Objective: Portal pressure gradient (PPG) after transjugular intrahepatic portosystemic shunt (TIPS) <12 mmHg has been reported as the only factor predictive of increase in platelet count. As flow velocities measured on Doppler ultrasound are related to pressure gradient based on the Bernoulli equation, we used this parameter to predict increased platelet count after TIPS placement.

Methods: A total of 161 consecutive patients who underwent TIPS placement entered this retrospective study.

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Purpose: To evaluate the imaging, histologic changes and safety of computed tomography (CT)-guided cryoablation of the parotid glands in a porcine model.

Materials And Methods: Unilateral CT-guided parotid gland cryoablation was performed in 5 juvenile miniature pigs. The ablated parotid glands underwent 2 cycles of 10-minute freeze and 5-minute thaw using three 17-g cryoprobes.

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Purpose: To evaluate image quality when using a CAIPIRINHA sampling pattern in comparison to a standard GRAPPA sampling pattern in patients undergoing a routine three-dimensional (3D) breathheld liver exam. CAIPIRINHA uses an optimized phase encoding sampling strategy to alter aliasing artifacts in 3D acquisitions to improve parallel imaging reconstruction.

Materials And Methods: Twenty patient volunteers were scanned using a 3D VIBE acquisition with an acceleration factor of four using a CAIPIRINHA and standard GRAPPA sampling pattern.

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Introduction: Percutaneous cryoablation is an emerging treatment option for the small renal mass. It poses a risk of thermal injury to adjacent tissues, limiting its application. We describe pneumodissection, a novel technique for preventing thermal injury during percutaneous cryoablation.

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Purpose: To obtain a simultaneous 3D magnetic resonance angiography and perfusion (MRAP) using a single acquisition and to demonstrate MRAP in the lower extremities. A time-resolved contrast-enhanced exam was used in MRAP to simultaneously acquire a contrast-enhanced MR angiography (MRA) and dynamic contrast-enhanced (DCE) perfusion, which currently requires separate acquisitions and thus two contrast doses. MRAP can be used to assess large and small vessels in vascular pathologies such as peripheral arterial disease.

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Computed Tomography (CT)-guided percutaneous cryoablation was performed in a 43-year-old patient with intractable epigastric abdominal pain caused by advanced adenocarcinoma of the pancreas and extensive celiac trunk involvement. Initial treatment with celiac plexus nerve neurolysis using local ethanol injection was unsuccessful. A 17-gauge 17-cm cryoablation probe (Galil Medical Inc.

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Purpose: To evaluate the effectiveness of direct intraparenchymal injection of platelets or fresh frozen plasma (FFP) into the needle tract before cutting needle biopsy to decrease postprocedural blood loss in pigs with normal and abnormal hemostasis.

Materials And Methods: A total of 12 Yorkshire-cross pigs were anesthetized and maintained on a respirator. The pigs were divided into three groups: three with normal hemostasis, five treated with warfarin anticoagulation, and four treated with aspirin.

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Objectives: To assess carotid intima media thickness (IMT) and cardiac biomarkers in HIV infected children on antiretroviral therapy (ART).

Methods: This was a single site, cross sectional, controlled observational study. We assessed carotid IMT, homocysteine, high-sensitivity C-reactive protein and myeloperoxidase levels in HIV infected children on stable ART for >or= 6 months.

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Surgery currently appears to be the most effective method to curtail the effects of morbid obesity and all of its comorbid conditions. Although the ideal procedure has yet to be devised, Roux-en-Y gastric bypass has proved to be successful for many morbidly obese patients pursuing weight loss and increased health. As the technical aspects of this procedure become less cumbersome and the patient population increases, it is vital for radiologists to be proficient in the specific evaluation of these patients, in order to provide optimal care.

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The interventionist can perform many emergent procedures with ultrasound guidance, because of its real-time, multiplanar imaging capability and portability. With the use of color Doppler, additional important information, such as aberrant vessels, can be ascertained to help plan needle trajectory. Ultrasound is also useful for nonemergent procedures, such as biopsies.

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