Virtual Ultrasonography Research Articles

Validation trial for efficacy of ultrasonographic measurement method to predict ascitic volume using virtual ultrasonography.

The aim of this study was to clarify whether ultrasound quantitative methods were positively correlated with volume of ascites evaluated by whole abdominopelvic CT. Sixty-eight patients with cirrhotic ascites were retrospectively analyzed. First, to confirm that virtual ultrasonography (VUS) is an alternative method to conventional ultrasound, 22 patients underwent both conventional ultrasonography and VUS. Second, the efficacy of US quantitative methods (3-point method, 4-point method, 5-point method, and Matsumoto's method) was confirmed by VUS in 68 patients. We assessed whether the ascites volume predicted by VUS corresponded with that calculated by 3D-CT. Of the 68 patients, 23 patients were analyzed before and after administration of tolvaptan. The predictive volumes calculated by VUS were remarkably relative to those yielded by conventional US. Correlations between exact volume and those measured by VUS were significantly high (3-point method: r = 0.882, p < 0.001; 4-point method: r = 0.797, p < 0.001; 5-point method: r = 0.836, p < 0.001; Matsumoto's method: r = 0.453, p < 0.001). Correlations between decreasing volume on 3D-CT and that measured by VUS were also significantly high in patients with administration of tolvaptan. Ascites volume measured by ultrasound was effective, especially the 3-point and 5-point methods. It was useful to assess the efficacy of diuretics in cirrhotic patients.

肝造影MRI検査の肝細胞相を用いた胆管描出と胆管近接肝細胞癌症例における仮想超音波の有用性

目的：本研究は，胆管の解剖学的構造を超音波検査で評価することと， Gd-EOB-DTPA（gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid）造影MRIの肝細胞相において肝内胆管の描出能を解析し，仮想超音波像を局所療法支援画像として用いたラジオ波焼灼術（RFA）の安全性と有用性を明らかにすることを目的とした．方法：本研究は施設内倫理審査委員会によって承認され，本研究に参加することに対するインフォームドコンセントを書面で得た．Gd-EOB-DTPA造影MRIを施行した肝腫瘍を有する201例で，胆管の解剖学的構造を評価した．これらの患者のうちの81例に，超音波とGd-EOB-DTPA造影MRIから構築した仮想超音波を支援画像に用いてラジオ波焼灼術（RFA）を施行した．また，23例で腫瘍が中部胆管から半径5 mm以内に存在していた．結果：Gd-EOB-DTPA造影MRIで構築した仮想超音波画像によって，総胆管，左肝管，右肝管をそれぞれ96.5％，94.0％，89.6％で描出することができた．仮想超音波検査装置を使用して，標的とした肝細胞癌と胆管を全患者で描出することができ，重篤な合併症はみられなかった．結論：Gd-EOB-MRIによる仮想超音波像を構築することで腫瘍と胆管の位置関係を把握し胆管損傷を予防できる．

PD18-02 SYNCHRONOUS REAL-TIME VIRTUAL SONOGRAPHY WITH THREE-DIMENSIONAL COMPUTED TOMOGRAPHY SCAN NAVIGATION TO CREATE PERCUTANEOUS RENAL ACCESS TO THE TARGET CALIX DURING PERCUTANEOUS NEPHROLITHOTOMY

You have accessJournal of UrologyStone Disease: Surgical Therapy II1 Apr 2016PD18-02 SYNCHRONOUS REAL-TIME VIRTUAL SONOGRAPHY WITH THREE-DIMENSIONAL COMPUTED TOMOGRAPHY SCAN NAVIGATION TO CREATE PERCUTANEOUS RENAL ACCESS TO THE TARGET CALIX DURING PERCUTANEOUS NEPHROLITHOTOMY Tatsuhiko Hoshii and Tsutomu Nishiyama Tatsuhiko HoshiiTatsuhiko Hoshii More articles by this author and Tsutomu NishiyamaTsutomu Nishiyama More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1181AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Percutaneous renal access in the context of percutaneous nephrolithotomy (PNL) for kidney stones is a difficult technique, requiring rapid and precise access to a particular calix. We present the usefulness of synchronous real-time virtual ultrasonography (US) (RVS) with three-dimensional (3D) computed tomography (CT) scan navigation to create percutaneous renal access to the target calix during PNL. METHODS We performed thin-slice contrast-enhanced CT examinations in a prone position before PNL. RVS system consists of an ultrasound scanner, a position sensor unit, and a computer with RVS software (HI VISION Preirus; Hitachi Aloka Medical, Tokyo, Japan). (Figure) Multiplanar reconstruction images were reconstructed using CT. The previously acquired CT data were loaded onto RVS system. The patients were placed in a prone position. While the operator handled RVS system, the ultrasound machine generated multiplanar reconstruction images from the CT volume data, corresponding to the US images of the same or very similar cross section. The magnetic sensor on the sonography probe precisely captured the magnetic field alternation of the position, direction, or rotation via the transmitter placed at the patient’s counter side of the lesion. We could mark the target calix detected on CT. Virtual images with marks were revisualized while using conventional US that helped the operator perform percutaneous renal access to the target calix. RESULTS We performed percutaneous renal access to the target calix during percutaneous nephrostomy in the context of PNL successfully using synchronous RVS with 3D CT scan navigation for a 26-year-old man with right kidney stones. CONCLUSIONS We will be able to create efficiently minimally invasive percutaneous renal access to the target calix using RVS system. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e404 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Tatsuhiko Hoshii More articles by this author Tsutomu Nishiyama More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Usefulness of a New Three-Dimensional Simulator System for Radiofrequency Ablation.

Multipuncture radiofrequency ablation is expected to produce a large ablated area and reduce intrahepatic recurrence of hepatocellular carcinoma; however, it requires considerable skill. This study evaluated the utility of a new simulator system for multipuncture radiofrequency ablation. To understand positioning of multipuncture electrodes on three-dimensional images, we developed a new technology by expanding real-time virtual ultrasonography. We performed 21 experimental punctures in phantoms. Electrode insertion directions and positions were confirmed on computed tomography, and accuracy and utility of the simulator system were evaluated by measuring angles and intersections for each electrode. Moreover, to appropriately assess placement of the three electrodes, puncture procedures with or without the simulator were performed by experts and non-experts. Technical success was defined as maximum angle and distance ratio, as calculated by maximum and minimum distances between electrodes. In punctures using 2 electrodes, correlations between angles on each imaging modality were strong (ultrasound vs. simulator: r = 0.991, p<0.001, simulator vs. computed tomography: r = 0.991, p<0.001, ultrasound vs. computed tomography: r = 0.999, p<0.001). Correlations between distances in each imaging modality were also strong (ultrasound vs. simulator: r = 0.993, p<0.001; simulator vs. computed tomography: r = 0.994, p<0.001; ultrasound vs. computed tomography: r = 0.994, p<0.001). In cases with 3 electrodes, distances between each electrode correlated strongly (yellow-labeled vs. red-labeled: r = 0.980, p<0.001; red-labeled vs. blue-labeled: r = 0.953, p<0.001; yellow-labeled vs. blue-labeled: r = 0.953, p<0.001). Both angle and distance ratio (expert with simulator vs. without simulator; p = 0.03, p = 0.02) were significantly smaller in procedures performed by experts using the simulator system. The new simulator system appears to accurately guide electrode positioning. This simulator system could allow multipuncture radiofrequency ablation to be performed more effectively and comfortably.

Co-located haptic interaction for virtual USG exploration.

Ultrasonography is a widespread diagnostic technique that can take advantage of virtual reality for the purpose of training and rehearsal. The placement, orientation and body interaction of the probe is fundamental for the execution of the exploration. This paper introduces a virtual reality setup that employs visuo-haptic feedback for virtual ultrasonography. The haptic feedback is provided by desktop delta-like haptic interface with a 3D printed ultrasonography probe, and features haptic point-cloud rendering with implicit surface rendering. The visual feedback is provided by a Head Mounted Display that displays the virtual body, the probe and the operator's hand while not in contact with the probe. The system provides a co-located experience by means of precise calibration of the reference system allowing to synchronize the display of the hand and the probe with the location of the corresponding physical entities.

Characterization of the biliary tract by virtual ultrasonography constructed by gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging.

This study aimed at prospectively evaluating bile duct anatomy on ultrasonography and evaluating the safety and utility of radiofrequency ablation (RFA) assisted by virtual ultrasonography from gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). The institutional review board approved this study, and patients provided written informed consent prior to entry into the study. Bile duct anatomy was assessed in 201 patients who underwent Gd-EOB-DTPA-enhanced MRI for the evaluation of hepatic tumor. Eighty-one of these patients subsequently underwent RFA assisted by ultrasound imaging. In 23 patients, the tumor was located within 5 mm of the central bile duct, as demonstrated by MRI. Virtual ultrasonography constructed by Gd-EOB-enhanced MRI was able to visualize the common bile duct, left hepatic duct, and right hepatic duct in 96.5, 94.0, and 89.6 % of cases, respectively. The target hepatic tumor nodule and biliary duct could be detected with virtual ultrasonography in all patients, and no severe complications occurred. The running pattern of the bile ducts could be recognized on conventional ultrasound by referencing virtual ultrasonography constructed by Gd-EOB-DTPA-enhanced MRI. RFA assisted by this imaging strategy did not result in bile duct injury.

Ultrassonografia Virtual Em Obstetrícia No Primeiro Trimestre

Ultrassonografia Virtual Em Obstetrícia No Primeiro Trimestre

Real‐time virtual ultrasonographic radiofrequency ablation of renal cell carcinoma

To evaluate the usefulness of real-time virtual ultrasonography (RVS) as a new navigational tool for percutaneous radiofrequency ablation (RFA) of solid renal cell carcinoma (RCC). Ten patients with 13 RCCs were treated with percutaneous RFA using RVS, which displays ultrasonograms and corresponding multiplanar reconstruction images of computed tomography in parallel. RVS allowed excellent anatomical visualization and precise navigation of RFA for RCC. All patients were treated successfully in one session with percutaneous RVS RFA. There were no significant complications, and none of the patients had a local tumour recurrence during the follow-up. RVS for RFA of solid RCC is a new and promising alternative imaging method.

Usefulness of contrast‐enhanced ultrasonography with abdominal virtual ultrasonography in assessing therapeutic response in hepatocellular carcinoma treated with radiofrequency ablation

Contrast-enhanced computed tomography (CECT) is regarded as the gold standard for assessing the efficacy of radiofrequency ablation (RFA) against hepatocellular carcinoma (HCC). We evaluated the efficacy of virtual ultrasonography (VUS) with contrast-enhanced ultrasonography (CEUS) vs. CECT for assessing the response to RFA. Study 1: The therapeutic responses in 22 patients with 26 HCC nodules were assessed by CEUS with VUS as well as by CECT. The efficacy of treatment was based on whether the safety margin was greater than 5 mm after RFA. Study 2: In seven patients with seven HCC nodules, the nodules were treated by RFA and the therapeutic efficacy was assessed by CEUS with VUS. The number of RFA sessions was assessed. Compared with CECT, CEUS with VUS had a specificity of 77%, a sensitivity of 91.6%, and an accuracy of 84%. When the therapeutic response to RFA was analyzed by CECT only, 1.86 +/- 0.69 assessments (mean) were required, while when response was assessed by CEUS with VUS, 1.14 +/- 0.38 CECT assessments were required (P = 0.03). CEUS with VUS is effective in assessing the therapeutic response to RFA of HCC. Moreover, the number of CECT scans required is reduced by this approach.

Ultra-sonografia virtual: reprodutibilidade intra-observador

OBJETIVO: Analisar a reprodutibilidade intra-observador da ultra-sonografia tridimensional (US3D) real com a US virtual, nas modalidades multiplanar e volumétrica. MATERIAIS E MÉTODOS: Foram examinados, prospectivamente, 132 blocos provenientes de 44 avaliações de 26 conceptos. Dezoito conceptos tinham idade gestacional ecográfica de oito semanas a oito semanas e seis dias, e 26 tinham de dez semanas a dez semanas e seis dias. Realizou-se a US3D, analisando-se: comprimento cabeça-nádega, saco gestacional, saco amniótico, translucência nucal, conduto onfalomesentérico, vesícula vitelínica, membros superiores, membros inferiores, distinção cabeça-tórax, perfil da face, coronal da face, implantação das orelhas, perfil da coluna, coronal da coluna, parede abdominal fechada. Foram obtidos três blocos por concepto para posterior realização da US virtual. A análise estatística foi feita utilizando-se o teste t de Student, o teste de McNemar e o kappa. RESULTADOS: No grupo I, a avaliação ultra-sonográfica 3D real multiplanar versus 3D virtual multiplanar, na análise das variáveis contínuas, evidenciou diferença significativa para todas. Na avaliação das variáveis categóricas, evidenciou-se que todas não apresentaram diferença significativa. No grupo II, a avaliação ultra-sonográfica 3D real volumétrica versus 3D virtual volumétrica demonstrou diferença significativa apenas para a variável implantação de orelhas. Os resultados das análises das variáveis categóricas evidenciaram concordância para a maioria das variáveis analisadas em ambos os grupos. CONCLUSÃO: Há reprodutibilidade intra-observador da US3D com a modalidade virtual, multiplanar e volumétrica.

Ｒｅａｌ‐ｔｉｍｅ ｖｉｒｔｕａｌ ＵＳ像が診断に役立った，胆嚢静脈還流による偽腫よう性病変の１例

Most recent modalities for diagnosing hepatic tumors are based on evaluation of the arterial and portal flow of the tumors. However, pseudo-lesions resulting from A-P shunting, and aberrant circulation of splancnic veins may occur, which often make it difficult to reach a definitive diagnosis. Real-time virtual ultrasonography, however, presents a virtual cross-section reconstructed from CT data. This modality has proven to be very useful for the detection of lesions which are difficult to find with the usual methods. With this modality, we could identify a pseudo-lesion co-existing with HCC from an actual tumor. The dignosis was based on both the image showing the continuation of the lesion to the cyctic wall and the results of a histological examination performed with reference to the virtual US image.