Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
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Volume 68, Issue 7
Displaying 1-17 of 17 articles from this issue
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Opening Article
Original
  • Evaluation of the Detectability of Vascular Stenosis Using Non-contrast Magnetic Resonance Angiography with Various Electrocardiographically-gated Three-dimensional Fast Spin Echo Sequences
    Yuta Izuno, Yasuhiro Hiai, Tetsuya Yoneda, Takashi Okigawa, Takeshi Oh ...
    2012 Volume 68 Issue 7 Pages 817-824
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.817
    JOURNAL FREE ACCESS
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    Various three-dimensional fast spin echo (3D-FSE) sequences are used for non-contrast magnetic resonance angiography (MRA). Differences in the ability to detect vascular stenosis using these sequences, however, have not yet been evaluated. The purpose of this study is to evaluate the usefulness of each sequence for the detection of vascular stenosis by using a vascular phantom. The phantom consisting of silicon tubes with 30% and 70% stenosis of luminal diameter and fluids close to T2 value of blood were used for the study. Non-contrast MRA with half-Fourier acquisition single-shot turbo spin echo (HASTE)-noncontrast magnetic resonance angiography of arteries and veins (NATIVE), sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE)-NATIVE, fresh blood imaging (FBI) and triggered angiography non contrast enhanced (TRANCE) sequences was performed by using the phantom which can be varied in terms of the steady flow velocity. Each stenosis was quantitatively estimated by the stenosis index (SI) calculated from the signal intensities on acquired images. The signal intensity of the non-stenotic vascular site markedly decreased at more than a flow rate of 20 cm/s in all sequences. Significant decrease in the signal intensity was observed in the distal point from the stenosis area on these images acquired by using HASTE-NATIVE and FBI sequences. FBI and TRANCE sequences showed a more accurate SI for 30% stenosis than HASTE-NATIVE and SPACE-NATIVE sequences. SI for 70% stenosis was overestimated in all sequences at 5 cm/s of diastolic flow rate. In conclusion, the ability to detect vascular stenosis on non-contrast MRA image using 3D-FSE sequences depends on the image quality during diastolic phase in the cardiac cycle. FBI and TRANCE sequences are useful to detect the mild arterial stenosis.
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Note
  • Influence of High-definition Multileaf Collimator for Three-dimensional Conformal Radiotherapy and Intensity-modulated Radiotherapy of Prostate Cancer
    Sachie Fujimoto, Kaoru Ono, Kengo Furukawa, Tsuyoshi Kudo, Yukio Akagi ...
    2012 Volume 68 Issue 7 Pages 825-834
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.825
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    The focus of this work is to evaluate the dosimetric impact of treatment planning for three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) of prostate cancer using Varian/BrainLAB 120-leaf high-definition multileaf collimator (HD120 MLC) with 2.5 mm leaf width and Varian 120-leaf millennium multileaf collimator (M120 MLC) with 5 mm leaf width. We measured the leaf transmission and dosimetric leaf gap (DLG) of two multileaf collimator (MLC) systems using Farmer ionization chamber. The dosimetric impact of treatment planning for 3DCRT and IMRT of prostate cancer for ten clinical cases using two MLC systems was evaluated quantitatively. 3DCRT was divided to 3DCRTmiddle as fitting at middle of leaf tip and 3DCRToutside as fitting at outside of leaf tip. The leaf transmission factor and DLG of HD120 MLC for 6 and 10 MV X-ray decreased by 0.2% and 1 mm, respectively, compared to M120 MLC. The mean conformity index of PTV of treatment planning for prostate 3DCRTmiddle, 3DCRToutside, and IMRT decreased by 0.9%, 6.6%, and 0.9% and the mean homogeneity index increased 2.3%, 13.0%, and 4.2%, respectively. The mean V20, V40, and V65 decreased by 2.4%, 6.6%, and 4.5% for bladder and 3.3%, 6.1%, and 5.9% for rectum, respectively. The results of this work demonstrated that the dose conformity of PTV improved and the dose of bladder and rectum decreased for 3DCRT and IMRT of prostate cancer using HD120 MLC compared to M120 MLC, because of reduction of leaf width, leaf transmission, and rounded leaf end transmission.
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Clinical Technologies
  • Estimating Elapsed Time of Brain Hemorrhage Using Computed Tomography Value-based Parameters
    Ken Furuya, Shinji Akiyama, Kouji Nakamura, Yoshitomo Sano
    2012 Volume 68 Issue 7 Pages 835-840
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.835
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    We measured the time-dependent change of computed tomography (CT) values for a blood sample in a syringe during 20 days expecting that the (average, maximum) CT values may be used to estimate the elapsed time after hemorrhage. The average CT value (CTave) rapidly increased for the first 50 min. The maximum CT value (CTmax) increased step by step to take the largest value (82.4 HU) one day later, and subsequently the CTmax decreased slowly to become 72.0 HU 20 days later. We conclude that the rapid increase of the CTave at the beginning is due to the fibrin generation, the increase of the CTmax is a result of the formation of the fibrin net, and the subsequent decrease of CTmax is caused by fibrinolysis. Tentative experimental formula for the time-dependent CTmax change at each increasing stage and decreasing stage are given to estimate the elapsed time after hemorrhage.
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  • Usefulness of Lower Extremity Magnetic Resonance Venography with Two-dimensional Spiral Gradient Echo Sequence and Effect of Patient Positioning on the Visualization of Lower Extremity Veins
    Makoto Watanabe
    2012 Volume 68 Issue 7 Pages 841-850
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.841
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    Purpose: We examined the two-dimensional-spiral-gradient-echo (2D-spiral-GRE) for magnetic resonance venography (MRV). In addition, five variations in patient positioning of the MRV were investigated to determine the best method of visualizing. Methods: First, flow phantom experiments were performed on a 1.5 T scanner. Using a flow phantom, the authors aimed to (1) measure the optimal TR (40, 60, 140, 190 ms), (2) measure the flip angle (20–60 degrees) and (3) determine the optimal combination of saturation pulse (S, I, A, P, R, L) and half acquisition method for MRV. Secondly, ten volunteers without vessel disease were imaged by phase contrast sequence for measured mean value of the venous area and velocity of the femoral and popliteal vein. The volunteers’ MRV images were compared qualitatively on visualization. Results: There is better demonstration of the veins under the longer repetition time (TR), resulting in a setting of 2–3 acquisitions ordering. Because the fluid or blood has been irradiated with pulsed radiofrequency multiple times, optimal FA was about 40 degrees. Combination of saturation pulse was slightly effective and the best saturation effect was seen in the half acquisition method. Volunteer study patient positioning, which involves the slight lifting up of the upper half of the body and continuous warming of the feet, has brought about a larger area and a slower velocity in the lower extremity veins. The greater veins and peripheral veins were demonstrated more accurately. Conclusion: 2D-spiral-GRE sequence was a useful method for lower extremity MRV. Furthermore, the most effective patient positioning for the lower extremity MRV was slightly lifting up the upper half of the body and continuously warming the feet. These enabled the best results to be obtained in the lower extremity MRV.
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  • Examination of the Chest Computed Tomography Scan Condition Optimization in Consideration of the Influence of the Position of the Arms
    Yoriaki Matsumoto, Takanori Masuda, Naoyuki Imada, Naoya Maruyama, Sat ...
    2012 Volume 68 Issue 7 Pages 851-856
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.851
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    Computed tomography automatic exposure control (CT-AEC) technique is calculated from a localizer radiograph. When we perform neck and chest CT examination, at first, we acquire localizer radiograph and neck images by placing the arm in a lowered position. Next, the arm is raised for the chest scan. Therefore, the localizer radiograph and subject information are different in the chest scan. In this situation, the chest scan with the use of the CT-AEC causes radiation over-dose. The purpose of this study is to optimize the CT-AEC by controlling noise index (NI), and make a chest CT scan condition considering the position of the arms. We measured the image noise (SD) in the phantom by using CT-AEC. In addition, dose length product (DLP) was recorded. Moreover, we examined the correlation with the clinical images. The results of our experiments show that radiation dose can be reduced with the image quality kept by controlling NI.
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  • Constructing a Database That Can Input Record of Use and Product-specific Information
    Satoru Kawai, Kenichi Satoh, Hideo Yamamoto
    2012 Volume 68 Issue 7 Pages 857-864
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.857
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    In Japan, patients were infected by viral hepatitis C generally by administering a specific fibrinogen injection. However, it has been difficult to identify patients who were infected as result of the injections due to the lack of medical records. It is still not a common practice by a number of medical facilities to maintain detailed information because manual record keeping is extremely time consuming and subject to human error. Due to these reasons, the regulator required Medical device manufacturers and pharmaceutical companies to attach a bar code called “GS1-128” effective March 28, 2008. Based on this new process, we have come up with the idea of constructing a new database whose records can be entered by bar code scanning to ensure data integrity. Upon examining the efficacy of this new data collection process from the perspective of time efficiency and of course data accuracy, “GS1-128” proved that it significantly reduces time and record keeping mistakes. Patients not only became easily identifiable by a lot number and a serial number when immediate care was required, but “GS1-128” enhanced the ability to pinpoint manufacturing errors in the event any trouble or side effects are reported. This data can be shared with and utilized by the entire medical industry and will help perfect the products and enhance record keeping. I believe this new process is extremely important.
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  • Fundamental Study of Three-dimensional Coherent Oscillatory State Acquisition for the Manipulation of Image Contrast: 3D-COSMIC in the Spinal Region
    Shinjiro Kugimiya, Hisamitsu Kawasaki, Keiko Kaneko, Masato Sakai, You ...
    2012 Volume 68 Issue 7 Pages 865-870
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.865
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    Balanced sequence, three-dimensional fast imaging employ steady state acquisition (3D-FIESTA) as an example, was often used for colangiopancretography and aortagraphy in the chest and the aorta, and venography in the extremity and other body parts, because this had the high signal to noise ratio and the short acquisition time. 3D-coherent oscillatory state acquisition for the manipulation of image contrast (COSMIC) developed recently is a sequence thought about based on 3D-FIESTA. We investigated the basic property of 3D-COSMIC compared with 3D-FIESTA in phantom and volunteer scan image study. At result, 3D-COSMIC was superior to 3D-FIESTA at signal to noise ratio and contrast on phantom image, contrast and visual evaluation on volunteer scan image of detection of tissue on spinal region. 3D-COSMIC was useful sequence in spinal region.
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  • Utility of Sampling Perfection with Application Optimized Contrasts Using Different Flip Angle Evolutions Method in Carotid Artery Plaque Magnetic Resonance Imaging
    Tetsuya Urata, Hidetaka Yamamoto, Naoaki Ikuta, Masato Uchikoshi
    2012 Volume 68 Issue 7 Pages 871-879
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.871
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    In the carotid artery plaque diagnosis, it is said that properties evaluation is important. For this inspection, it is general to use electrocardiogram (ECG)-trigger-dark blood (DB)-fat suppression (fs)-turbo spin echo (TSE)-T1 weighted image (T1WI), T2WI, and magnetization prepared rapid gradient echo (MPRAGE) methods though many problems still remain. This time, a comparative study of the carotid artery plaque diagnosis that used the sampling perfection with application optimized contrasts was made. This used different flip angle evolutions method sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE) method that was 3 dimension (3D) imaging procedure that used variable flip angle with the law so far. The subjects were normal volunteers, handmade phantoms changed by T1 and T2 value, and the five patients on five cases who had taken carotid endoarterectomy (CEA) (male, mean 70.6 yr). Findings by the pathologist were obtained for the CEA enforcement patient. There is an excellent result in the contrast ratio by phantom, the signal intensity ratio of a clinical patient, and the comparison with pathological findings. The SPACE method can solve various problems, be evaluated by a properties evaluation of the plaque, a grasp of the range, and an arbitrary section, and be devised as a useful imaging procedure.
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  • Carotid Plaque Assessment Using Inversion Recovery T1 Weighted-3 Dimensions Variable Refocus Flip Angle Turbo Spin Echo Sampling Perfection with Application Optimized Contrast Using Different Angle Evolutions Black Blood Imaging
    Yuji Inoue, Masami Yoneyama, Masanobu Nakamura, Satoshi Ozaki, Kenjiro ...
    2012 Volume 68 Issue 7 Pages 880-888
    Published: July 20, 2012
    Released on J-STAGE: July 23, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.7.880
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    Vulnerable plaque can be attributed to induction of ischemic symptoms and magnetic resonance imaging of carotid artery is valuable to detect the plaque. Magnetization prepared rapid acquisition with gradient echo (MPRAGE) method could detect hemorrhagic vulnerable plaque as high intensity signal; however, blood flow is not sufficiently masked by this method. The contrast for plaque in T1 weighted image (T1WI) could not be obtained sufficiently with black blood image (BBI) by sampling perfection with application optimized contrast using different angle evolutions (SPACE) method as turbo spin echo (TSE). In addition, an appearance of artifact by slow flow is a problem. Considering these controversial situations in plaque imaging, we examined the modified BBI inversion recovery (IR)-SPACE in which IR was added for SPACE method so that the contrast for plaque in T1WI was optimized. We investigated the application of this method in plaque imaging. As a result of phantom imaging, the contrast for plaque in T1WI was definitely obtained by choosing an appropriate inversion time (TI) for the corresponding repetition time. In clinical cases, blood flow was sufficiently masked by IR-SPACE method and the plaque imaging was clearly obtained in clinical cases to the same extent as MPRAGE method. Since BBI with IR-SPACE method was derived from both IR pulse and flow void effect, this method could obtain the blood flow masking effect definitely. The present study suggested that SPACE method might be applicable to estimate properties of carotid artery plaque.
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The 39th Autumn Scientific Congress
Educational Lecture–Radiation Measurement in the Clinical Setting
Basic Lecture–Radiation Therapy Technology: Basic Strategy
Basic Lecture–From Diagnosis of the Breast to Treatment
Clinical Technology Course
Virtual Interview for Graduate School and Laboratories
JIRA Topics
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