T Igarashi

Seirei Sakura Citizen Hospital, Сакура, Chiba, Japan

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Publications (149)223.72 Total impact

  • [Show abstract] [Hide abstract]
    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.
    10/2014;
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    ABSTRACT: doi: 10.1142/S0219519414500523
    Journal of Mechanics in Medicine and Biology 05/2014; · 0.76 Impact Factor
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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.
    Translational Engineering in Health and Medicine, IEEE Journal of. 01/2014; 2:1-9.
  • Journal of Medical Imaging and Health Informatics 03/2013; 3(1):101-106. · 0.64 Impact Factor
  • 2013 IEEE International Ultrasonics Symposium (IUS2013), Prague, Czech Republic; 01/2013
  • Source
    Tatsuo Igarashi
    International Journal of Urology 12/2012; · 1.73 Impact Factor
  • Source
    Tatsuo Igarashi
    International Journal of Urology 06/2012; 19(9):890. · 1.73 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. · 1.75 Impact Factor
  • 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
  • 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.
  • Japanese journal of applied physics : JJAP. 01/2012; 51(7):07GF04-1-8.
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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. · 1.07 Impact Factor
  • Urology 09/2011; 78(3). · 2.42 Impact Factor
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    ABSTRACT: Endoscopic image of the tubular organs is recorded as discontinuous shots taken from a fixed angle without 3D or objective information. Presentation of a 3D picture of intraluminal cavity of the tubular organ covering whole-range of observation from continuous endoscopic video frames would be effective for the diagnosis and identification of the lesion, as well as offering intuitive information to the patients. In this paper, a new method for processing virtual endoscopy from "actual" endoscopic video images is proposed to observe the internal structures of tubular organs. The method consists of two steps of processing: 1. the panoramic image is processed from video image of endoscopy or the tubular organs where the endoscope was pulled at a constant speed automatically using a stepper motor or manually by a doctor. 2. the 3D-height information was extracted from a panoramic image using the intensity of the pixel based on the inverse-square low. This method is carried out under the assumption that the same part of the organ has similar property of reflection and the endoscope is the only source of illumination inside the body. The extracted height information will correspond with the distance between the point of the object and the endoscope. Finally, the virtual tubular object is reconstructed with the panoramic image texture. This method makes use of the advantages of conventional virtual endoscopy processed from "actual" endoscopic images, affording intuitive, multi-angle observation of the objects with color information and fine resolution. To date, virtual endoscopic images have been successfully processed from endoscopic video files for the colon, esophagus, ureter, and the urethra. Such images offer sharing of intuitive information for doctors and patients, and are promising in improving the accuracy of diagnosing the lesions.
    Journal of Medical Imaging and Health Informatics 02/2011; 1(1):13-20. · 0.64 Impact Factor
  • Annual Meeting of World Congress of Endourology and SWL, Kyoto, Japan; 01/2011
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    ABSTRACT: In this study, a multi modality fusion imaging technique was proposed for guiding a new laparoscopic surgery method. This new method was evaluated during a phantom experiment. An advantage of this new laparoscopic surgery method is that the internal structures can be imaged during surgery using ultrasonic diagnostic equipment. This method can display the internal organ structure by overlaying a three dimensional (3-D) ultrasonic image over a 3-D laparoscopic image. The registration of the 3-D images is performed by registering the surface of the target organ which is found in the two 3-D images. In the 3-D laparoscopic image, the surface shape of the target organ is reconstructed from two 2-D laparoscopic images. In the 3-D ultrasonic image, the internal structure and the surface shape of the target organ are directly reconstructed from volumetric ultrasonic image acquired by US diagnostic equipment. Results obtained using the proposed method on tissue mimicking phantoms led to a registration accuracy of 9.72+/-3.79 mm. The total processing time was 3.2 min on a personal computer (Xeon processor, 3-GHz CPU). The structural information obtained from our method permit to visualize target organs during laparoscopic surgery.
    2011 IEEE International Ultrasonics Symposium, Orlando, USA; 01/2011
  • Urology 01/2011; 78(3). · 2.42 Impact Factor
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    ABSTRACT: To evaluate in collaboration the clinical features of late recurrence of renal cell carcinoma (RCC). Late recurrence is one of the specific biologic behaviors of RCC; however, the clinical and pathologic features of the late recurrence of RCC are not fully understood. A total of 470 patients who had undergone curative treatment of RCC and had not developed recurrence within 10 years of follow-up were documented from 13 institutions of the board members of the Japanese Society of Renal Cancer. Multivariate analysis with Cox proportional hazards model was used to determine the pathologic and clinical factors affecting the late recurrence and survival of patients with RCC ≥10 years after surgery. Survival analysis was performed using the Kaplan-Meier method. During the 10-28-year (median 13.2) observation period, 30 patients (6.4%) developed a late recurrence. The disease-free survival rate at 15 and 20 years was 89.5% and 78.4%, respectively. Multivariate analysis showed that lymph node metastasis was the only factor to predict for late recurrence (P = .0334). Age at nephrectomy was the only prognostic factor for overall survival on multivariate analysis (P < .0001). Of the 470 patients, 30 had developed late recurrence in 44 sites, including the lung (36.4%), kidney (25%), and bone (13.6%), followed by the brain, pancreas, adrenal gland, lymph nodes, and liver. Late recurrences in the lung or kidney were observed at any time ≥10 years after nephrectomy. Late recurrence of RCC after initial treatment is not a rare event, and lifelong follow-up is necessary.
    Urology 10/2010; 77(2):379-84. · 2.42 Impact Factor
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    ABSTRACT: For novice surgeons, successful laparoscopic radical nephrectomy depends on the treatment of the renal vessels, and the use of computed tomography assists in navigation during the surgery. To navigate during surgery, three-dimensional volume-rendered images of the renal vessels, kidneys, and surrounding organs were created intraoperatively by the surgeon using an image-processing application. A surgeon adjusted the angle of view and the size of the images according to surgical views during the operation, using a wireless mouse enclosed in a sterilized bag. These images were simultaneously fused onto live video using image-capture software. Novice surgeons easily constructed the augmented reality images intraoperatively and were able to successfully treat the renal vessels. The combination of three-dimensional computed tomography volume-rendered images with live video is a valuable navigation system for use intraoperatively.
    Journal of endourology / Endourological Society 03/2010; 24(4):521-4. · 1.75 Impact Factor
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    ABSTRACT: In laparoscopic surgery, surgeons often encounter paradoxical vision according to their position against the camera position. Such a paradoxical vision evokes confusion and surely deteriorates surgical performance. Previous researches indicated inverted mirror image is useful to compensate this problem though upside-down inversion makes depth sensation perplex. To solve the dilemma, we proposed modified method that displays inverted mirror image plus perspective projection that adds simulated depth cue. After preparing the image adjustment software, trainer box, touch panel device to measure the motion of the forceps, we tested its validity in 36 participants including 10 experienced surgeons. Each participants were requested to push buttons following computer's assignment for ten times of task at three conditions: 1. stands parallel to the camera, 2. stands at the opposite side of the camera, 3. stands at the opposite side of the camera watching inverted mirror image with perspective projection. Mean duration of time for completion of the task was 23.1+/-5.0 seconds for the subjects stand parallel to the camera. It was 98.0+/-96.5 seconds and 43.3+/-24.3 seconds for the subject stands at the opposite side of the camera without and with transformed image, respectively. Paradoxical vision significantly deteriorated performance (p
    11th International Conference on Control, Automation, Robotics and Vision, ICARCV 2010, Singapore, 7-10 December 2010, Proceedings; 01/2010

Publication Stats

988 Citations
223.72 Total Impact Points

Institutions

  • 2007–2012
    • Seirei Sakura Citizen Hospital
      Сакура, Chiba, Japan
  • 1984–2012
    • Chiba University
      • • Department of Urology
      • • Graduate School of Medicine
      • • Research Center for Frontier Medical Engineering
      Chiba-shi, Chiba-ken, Japan
  • 1999–2008
    • Chiba University Hospital
      Tiba, Chiba, Japan
  • 2006
    • Saga-Ken Medical Centre Koseikan
      Kanzaki, Saga, Japan
  • 1987–2005
    • Asahi General Hospital
      Asahi, Chiba, Japan
  • 2002
    • Kyushu University
      Hukuoka, Fukuoka, Japan
  • 2001
    • Keio University
      • Department of Urology
      Tokyo, Tokyo-to, Japan
  • 2000–2001
    • Teikyo University
      • Department of Urology
      Tokyo, Tokyo-to, Japan