Tatsuo Igarashi

Chiba University, Tiba, Chiba, Japan

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Publications (168)273.14 Total impact

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    ABSTRACT: Single-agent interferon (IFN) is no longer regarded as a standard option for first-line systemic treatment of metastatic renal cell carcinoma (RCC) in Western countries. However, some patients with favorable-risk RCC may still achieve complete and long-lasting remission in response to IFN treatment. The present study compared favorable-risk Japanese patients with metastatic RCC Japanese patients who had been treated with IFN or tyrosine kinase inhibitor (TKI) therapy as a first-line systemic therapy. From 1995 to 2014, a total of 48 patients with favorable risk as defined by the Memorial Sloan Kettering Cancer Center criteria who did not receive adjuvant systemic therapy were retrospectively enrolled in this study. We assessed the tumor response rate, progression-free survival (PFS), and overall survival (OS). The objective response rate for first-line therapy was 29% in the IFN group and 47% in the TKI group, but this difference did not reach the level of statistical significance. Median OS for IFN and TKI was 71 and 47 months, respectively (p=0.014). Median first-line PFS for IFN and TKI was 20 and 16 months, respectively (no significant difference). First-line IFN therapy did not prove inferior to TKI therapy in terms of OS according to metastatic sites. IFN is associated with a survival benefit in Japanese patients with favorable-risk metastatic RCC in the era of targeted therapy. Further prospective study is needed.
    Korean journal of urology 03/2015; 56(3):205-11. DOI:10.4111/kju.2015.56.3.205
  • Takuro Ishii · Kazuyoshi Nakamura · Yukio Naya · Tatsuo Igarashi ·
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    ABSTRACT: Abstract Introduction: Transurethral surgery is widely accepted as standard therapy for male urethral obstruction. The present study was undertaken to identify and select lesions to be managed by processing endoscopic images of the urethra for assisting less invasive therapy in patients with voiding dysfunction. Material and methods: Cystourethroscopic video files of 25 patients with lower urinary tract symptoms were recorded before and after administration of alpha-1 adrenoceptor antagonists. Each video frame was restored and tagged with information indicating the position in the panoramic image of the urethra. A three-dimensional virtual urethra was created to indicate critical lesions for voiding dysfunction, together with fluid dynamics simulation of urine flow. Results: The urine stream was depicted in the virtual urethras in 19 patients. Before therapy, 17 patients showed vortex formation that was diminished after therapy in nine patients with a significant relationship in improvement of relative energy loss of flow (p=0.025). The narrowing points proximal to the vortex, candidate of lesions, were identified in the panoramic image and linked to the endoscopic image. Discussion: Therapeutic designing for endoscopic management was possible in patients with voiding dysfunction based on computational fluid dynamics, and would be promising as "focal" therapy for aging males.
    Minimally Invasive Therapy & Allied Technologies 10/2014; 24(3):1-7. DOI:10.3109/13645706.2014.964260 · 1.27 Impact Factor
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    ABSTRACT: Voiding dysfunction is a common disease among the elderly male population. However, few studies have elucidated the flow dynamics of the disease mechanism. We attempted to clarify the fluid dynamics of urine in the prostatic urethra (PU) in patients with bladder outlet obstruction (BOO), a common disease associated with voiding dysfunction. A model of normal PU and three phase models following the BOO progression were prepared using 3D CAD software tracing cystourethroscopic images. In fluid dynamics computation, the normal detrusor pressure was applied to the bladder side in each model. Results of fluid simulation were compared for flow trajectory line, fluid energy dynamics using Bernoulli's principle and pressure loss coefficient. In the BOO model, a large vortex was observed adjacent to the bladder outlet (BO) with increased hydraulic energy loss during the passage through the tract. In contrast, opening of the BO eliminated the vortex with reduction of hydraulic energy loss. These results corresponded with clinical data measured by catheterized pressure sensors inserted into the urethra, and those of urethral diameter measured by urethrography. Fluid dynamics simulation using CAD models can clarify the mechanism of voiding dysfunction in a less invasive and more acceptable way in patients with BOO.
    Journal of Mechanics in Medicine and Biology 05/2014; 14(4):1450052. DOI:10.1142/S0219519414500523 · 0.73 Impact Factor
  • Takuro Ishii · Yoichi Kambara · Tomonori Yamanishi · Yukio Naya · Tatsuo Igarashi ·
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    ABSTRACT: Voiding dysfunction is common in the aged male population. However, the obstruction mechanism in the lower urinary tract and critical points for obstruction remains uncertain. The aim of this paper was to develop a system to investigate the relationship between voiding dysfunction and alteration of the shape of the prostatic urethra by processing endoscopic video images of the urethra and analyzing the fluid dynamics of the urine stream. A panoramic image of the prostatic urethra was generated from cystourethroscopic video images. A virtual 3-D model of the urethra was constructed using the luminance values in the image. Fluid dynamics using the constructed model was then calculated assuming a static urethra and maximum urine flow rate. Cystourethroscopic videos from 11 patients with benign prostatic hyperplasia were recorded around administration of an alpha-1 adrenoceptor antagonist. The calculated pressure loss through the prostatic urethra in each model corresponded to the prostatic volume, and the improvements of the pressure loss after treatment correlated to the conventional clinical indices. As shown by the proposed method, the shape of the prostatic urethra affects the transporting urine fluid energy, and this paper implies a possible method for detecting critical lesions responsible for voiding dysfunction. The proposed method provides critical information about deformation of the prostatic urethra on voiding function. Detailed differences in the various types of relaxants for the lower urinary tract could be estimated.
    IEEE Journal of Translational Engineering in Health and Medicine 01/2014; 2:1-9. DOI:10.1109/JTEHM.2014.2316148
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    ABSTRACT: Laparoscopic surgery remains a challenging procedure because visualization of the internal target organ cannot be achieved from the laparoscopic image. We have proposed a laparoscopic surgery support method relying on three-dimensional (3D) images reconstructed using a stereo laparoscope and a 3D ultrasound system. The aim of this study is to develop a visualization system providing depth information about blood vessels within the liver. The shape and depth information of blood vessels are then correctly superimposed on a 2D laparoscopic image on the basis following careful registration. The coordinates of the laparoscope and the ultrasound are registered by aligning the two 3D liver surface shapes obtained by a stereo laparoscope and an ultrasonic diagnostic equipment with a mechanically moved convex probe using multiple image processing techniques. Then, the shape and depth information within the liver are calculated, and color-coded blood vessel depth information is superimposed on the original 2D laparoscopic image. In a phantom experiment, the registered 3D images were the mean squared error (MSE) of 5.89 ± 3.11 mm. The 2D laparoscopic image was superimposed the color-coded depth of the blood vessels segmented from the 3D ultrasonic data. The calculation of depth information had the MSE of 1.88 ± 1.40 mm.
    2013 IEEE International Ultrasonics Symposium (IUS2013), Prague, Czech Republic; 07/2013
  • Rodiyan Gibran Sentanu · Kohei Horiuchi · Takuro Ishii · Tatsuo Igarashi ·
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    ABSTRACT: Recently, a number of methods have been developed that make it possible to estimating elasticity and flexibility of lower urinary tract. However, those methods failed to estimate elasticity of bladder outlet directly. This paper describes a novel method for female bladder neck elasticity and flexibility estimation based on cystourethroscopic image. The first step is to extract edges from the original image based on Canny detector and morphological operations. The region of interest (ROI) was defined as the lowest part of the detected edge. The results of edge detection were compared with the original image in order to check the accuracy of proposed method. The deformation was defined as the vertical movement of certain points in which correspond to bladder neck outlet. Furthermore, the elasticity estimation may be acquired by taking the Fourier transform of the deformation wave. The experimental results indicate that this method is able to detect the deformation. By extracting the deformation, it is possible to define the vibration caused by intermittent irrigation. This vibration is expected to have correspondence to its elasticity and flexibility. Finally, directions for future work are suggested.
    Journal of Medical Imaging and Health Informatics 03/2013; 3(1):79-83. DOI:10.1166/jmihi.2013.1133 · 0.64 Impact Factor
  • Tatsuo Igarashi · Masayuki Teranuma · Takuro Ishii ·
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    ABSTRACT: A new surgical system that irrigates abdominal cavity during operation was introduced with special attention to overage of hemorrhage using an extracorporeal cisterna set on the small incision of the abdomen. Standard surgical maneuver was done successfully, including cutting, dissecting and cessation of hemorrhage. The article refers to present status about abdominal irrigation or lavage in various therapeutic modalities, its advantages and draw backs, and its impact in promoting new modality of surgeries.
    Journal of Medical Imaging and Health Informatics 03/2013; 3(1):59-64. DOI:10.1166/jmihi.2013.1130 · 0.64 Impact Factor
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    Satoki Zenbutsu · Tatsuo Igarashi · Tadashi Yamaguchi ·
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    ABSTRACT: Laparoscopic surgery is a challenging surgical operation because inside information about the target organ cannot be fully understood from the laparoscopic image. In this study, a fusion technique of surface information of a laparoscope and inside blood vessel information of ultrasound is proposed for guidance during laparoscopic surgery. The proposed technique can display the blood vessel depth inside of the target organ by projecting the ultrasonic image over a laparoscopic image. The registration of the laparoscopic and ultrasonic images is performed by registering the surface of the target organ, which is found in the ultrasonic volumetric data and stereoscopic images acquired by the stereo laparoscope. The performance of the proposed technique was evaluated experimentally using a tissue-mimicking phantom. The total computation time was 8.61 s on a personal computer (Xeon processor, 3 GHz CPU). The location of the blood vessel including depth information permits the visualization of risky areas during laparoscopic surgery.
    Journal of Medical Imaging and Health Informatics 03/2013; 3(1-1):101-106. DOI:10.1166/jmihi.2013.1134 · 0.64 Impact Factor

  • Journal of Medical Imaging and Health Informatics 03/2013; 3(1):48-50. DOI:10.1166/jmihi.2013.1129 · 0.64 Impact Factor
  • Takuya Akagi · David Gomez · Jose Gonzalez · Tatsuo Igarashi · Wenwei Yu ·

    Autonomous Control Systems and Vehicles, 01/2013: pages 279-289; Springer.
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    Tatsuo Igarashi ·

    International Journal of Urology 12/2012; 20(6). DOI:10.1111/iju.12019 · 2.41 Impact Factor
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    Tatsuo Igarashi ·

    International Journal of Urology 06/2012; 19(9):890. DOI:10.1111/j.1442-2042.2012.03070.x · 2.41 Impact Factor
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    ABSTRACT: To examine the efficacy of an alpha-1 blocker and its correlation to structural alteration of the prostatic urethra and the loss of energy in the urine flow using a virtual urethra processed from an endoscopic video image. Video images of the prostatic urethra were recorded during cystourethroscopy in 11 patients with benign prostatic hyperplasia (BPH) before and after treatment with an alpha-1 blocker, naftopidil. The three-dimensional (3D) structure of the prostatic urethra was reproduced from video files. Fluid dynamic analysis and hydraulic energy calculations were performed using the "virtual" 3D urethral images. In 9 of 11 patients studied, an 11% improvement in the loss of energy (range, 1%-82%) was seen. Alpha-1 blocker treatment mediated the disappearance or decrease of the bulky vortex formation in seven patients, which led to an improved urinary stream. A positive correlation was found between improved energy loss and residual urine volume (P=0.0312). Alpha-1 blocker therapy led to a decreased energy loss in the urine flow in the prostatic urethra in relation to the improvement of clinical symptoms. The cystourethroscopy could be a tool to assess the urethral resistance in patients with BPH using image processing methodology.
    Journal of endourology / Endourological Society 04/2012; 26(9):1216-20. DOI:10.1089/end.2012.0078 · 1.71 Impact Factor

  • European Urology Supplements 02/2012; 11(1):e1116-e1116a. DOI:10.1016/S1569-9056(12)61112-9 · 3.37 Impact Factor
  • Tetsuro Onishi · Hiroyoshi Suzuki · Tatsuo Igarashi ·
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    ABSTRACT: We present a patient showing favourable response after combination treatment with interferon-α (IFN- α) and cyclooxygenase-2 (Cox-2) inhibitor (celecoxib) against metastatic renal cell carcinoma (RCC). The patient underwent left radical nephrectomy for RCC on 18th April, 2005. On follow-up computed tomographic scan, mediastinal metastasis was detected 3 years after nephrectomy, and metastasectomy was performed. The histological features were clear cell carcinoma as was the primary RCC, and immunohistochemical analysis revealed negative for Cox-2 staining both the primary and metastatic lesions. Aiming at the treatment of residual mediastinal RCC, the patient started to receive IFN-α, and this cytokine therapy lasted for 1 year and 2 months. Nevertheless, the outcome was progression of disease (PD), namely, new lung field lesions were observed. A different type of IFN-α treatment also resulted in PD. Based upon these results, a combination of IFN-α and Cox-2 inhibitor was newly adopted for treatment. After the combination therapy for 3 months, 68.75% of metastases disappeared. We concluded that Cox-2 inhibitor is a potent medicine in combination with IFN-α for metastatic lung tumour from RCC.
    Hinyokika kiyo. Acta urologica Japonica 01/2012; 58(1):25-9.
  • Satoki Zenbutsu · Tatsuo Igarashi · Jonathan Mamou · Tadashi Yamaguch ·

  • Takuro Ishii · Satoki Zenbutsu · Tatsuo Igarashi ·

    Computational Fluid Dynamics (CFD) in Medicine and Biology in conjunction with the 7th International Biofluid Mechanics Symposium, Ein Bokek, Israel; 01/2012
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    ABSTRACT: Recent surgical techniques have been advancing under endoscopic view and insufflation of carbon dioxide gas to expand the abdominal cavity. Isotonic fluid could be one candidate for expanding cavities to facilitate surgical maneuvering. We tested the feasibility and drawbacks of replacement of irrigating materials using a porcine model (water-filled laparoendoscopic surgery [WAFLES]). Laparoscopic cholecystectomy was performed in two porcine models using instillation of sorbitol solution as irrigant. Solution irrigation was performed through one of four ports, with drainage via another port. Conventional forceps equipped with a monopolar electrode for electrocautery, laparoscope, video processor, ultrasound, and transducer for measuring intraabdominal pressure were used. Laparoscopic cholecystectomy was successfully undertaken with the following benefits: (1) clear observation of the dissecting plane throughout maneuvering; (2) control of oozing and spilled bile by irrigation and suction; and (3) ultrasonographic and laparoscopic images can be obtained simultaneously without any restriction to probe location. However, two disadvantages should be noted: (1) difficulties in managing floating organs and (2) interruption of vision by blood. WAFLES provides some benefits for endoscopic surgery with proper devices, including apparatuses for irrigation and suction. Efficient irrigation and selection of proper irrigant and apparatuses are required to establish an acceptable procedure.
    Journal of Laparoendoscopic & Advanced Surgical Techniques 12/2011; 22(1):70-5. DOI:10.1089/lap.2011.0404 · 1.34 Impact Factor
  • G. Sakuyama · T. Ishii · T. Yamanishi · T. Igarashi ·

    Urology 09/2011; 78(3). DOI:10.1016/j.urology.2011.07.203 · 2.19 Impact Factor
  • K. Horiuchi · T. Ishii · Y. Naya · T. Yamanishi · T. Nakada · T. Igarashi ·

    Urology 09/2011; 78(3). DOI:10.1016/j.urology.2011.07.825 · 2.19 Impact Factor

Publication Stats

2k Citations
273.14 Total Impact Points


  • 1984-2015
    • Chiba University
      • • Department of Urology
      • • Graduate School of Engineering
      • • Research Center for Frontier Medical Engineering
      • • Graduate School of Medicine
      Tiba, Chiba, Japan
  • 2009
    • Seirei Sakura Citizen Hospital
      Сакура, Chiba, Japan
  • 2000-2008
    • Chiba University Hospital
      Tiba, Chiba, Japan
  • 1987-2005
    • Asahi General Hospital
      Asahi, Chiba, Japan
  • 2002
    • Kyushu University
      Hukuoka, Fukuoka, Japan
  • 2001
    • Keio University
      • Department of Urology
      Edo, Tokyo, Japan
  • 1986
    • Toyama Medical and Pharmaceutical University
      Тояма, Toyama, Japan