M Matsudaira

Publications (18)14.17 Total impact

• Article: Phantom studies for estimation of defect size on cardiac (18)F SPECT and PET: implications for myocardial viability assessment.

  I Matsunari, T Yoneyama, S Kanayama, M Matsudaira, K Nakajima, J Taki, S G Nekolla, N Tonami, K Hisada
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  ABSTRACT: SPECT with (18)F-FDG has emerged as an alternative to dedicated PET for the assessment of myocardial viability. However, whether FDG SPECT can reliably quantify the extent of viable and scarred myocardium is uncertain. The aim of this study was to investigate whether SPECT with an (18)F-labeled agent would provide information on defect size similar to that provided by dedicated PET. Imaging was performed using an elliptic cylinder chest phantom with simulated bone, lung, mediastinum, liver, and heart. (18)F was administered into the myocardium, mediastinum, right and left ventricular cavities, and liver. Plastic inserts (n = 11) ranging in size from 2% to 60% of the myocardium were used to simulate transmural myocardial infarctions. The chest phantom was imaged with a dedicated PET camera and with a double-head SPECT camera equipped with ultra-high-energy collimators. Both SPECT and PET data were analyzed using a semiquantitative polar map approach. Defects were quantified using various cutoff thresholds ranging from 30% to 80% of peak activity and were expressed as a percentage of the left ventricular myocardium. Defect size as measured by SPECT or PET was compared with true defect size. The measured SPECT defect size was highly variable depending on the cutoff used, whereas PET defect size was relatively constant over the range of cutoffs tested. The mean absolute difference between measured and true defect sizes was minimal at a cutoff of 50% of peak activity for both SPECT (3.3% +/- 3.3%) and PET (2.7% +/- 2.5%). For this threshold, both SPECT and PET measurements showed an excellent correlation with true defect size (r = 0.98 for SPECT and 0.99 for PET). The correlation between SPECT and PET measurements was also excellent (r = 0.99; P < 0.01). If an appropriate threshold is used to define a defect, SPECT with an (18)F-labeled agent can accurately measure defect size similarly to the manner of PET.
  Journal of Nuclear Medicine 11/2001; 42(10):1579-85. · 6.38 Impact Factor
• Article: [Dual isotope SPECT with 99mTc and 123I using four-energy-window (FEW) method].

  M Matsudaira, K Nakajima, N Tonami, K Hisada
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  ABSTRACT: We devised "four-energy-window" (FEW) method which permits simultaneous acquisition for dual isotope single photon emission tomography (SPECT) studies using 99mTc and 123I of which photopeak is in close vicinity to each other. This acquisition method requires a total of four energy windows: two main windows for 99mTc (126-143 keV) and 123I (156-175 keV), respectively, and two 5% sub-windows which are set below the 99mTc window and above the 123I window, respectively. Two virtual windows (5%) are additionally set above the 99mTc and below the 123I window, respectively, to apply the triple-energy-window (TEW) method for the scatter correction. A phantom study demonstrated that photocounts from the two radionuclides could be completely separated from each other and that SPECT images obtained had preferable property for quantitative analysis. This method was applied to clinical, dual-radionuclide myocardial studies using 99mTc-MIBI and 123I-BMIPP, and was found to provide excellent images each tracer.
  Kaku igaku. The Japanese journal of nuclear medicine 12/1997; 34(11):1013-20.
• Article: [A new approach to eliminate background count from gated blood pool image (iterative constant subtraction method). Part 1: Principle and technique].

  M Matsudaira, K Nakajima
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  ABSTRACT: It is important for obtaining a left ventricular volume curve and ejection fraction from a multigated blood pool image (MGBP image) to accurately subtract the background (BG) from the image. We devised a new method of accurately subtracting the BG with good reproducibility. This method (tentatively called the ICS method) is as follows. An image, on which n times (n = 0, 1, 2, 3,..., N-1) an adequately low constant (k) is subtracted from the MGBP image at every pixel of the image matrix, is prepared. When n equals 0, constant is not subtracted from the image, therefore it is original MGBP image. Then the original (n = 0) and constant (nk: n = 1, 2, 3,..., N-1) subtraction MGBP images were prepared. The constant was defined as about 5% of the maximum pixel count in the end-diastole of the left ventricle. Rough region of interest (ROI) were set at the left ventricle on these MGBP images, and time activity curves (TACs, left ventricular volume curves) on each image were prepared. These N kinds of curves are shifted in parallel for normalization in the first frame (end-diastole). The first frame count on the original MGBP image is normalized. As a result, TACs obtained by inadequate subtraction in which subtraction of the constant does not reach the BG count, overlap completely, while TACs obtained by subtraction over the BG gradually separate from the overlapping curves. The MGBP image including a curve located in the border between the overlapping curve and the separated curve is regarded as the image accurately subtracting the BG, and the constant of subtraction (nk) as the BG count for each pixel. The border is obtained by analyzing changes in count of the end-systolic frame of each TAC normalized. The ICS method provides computer software that is performed automatically within a short time by setting a rough ROI at the left ventricle on the end-diastolic MGBP image.
  Kaku igaku. The Japanese journal of nuclear medicine 11/1996; 33(10):1053-63.
• Article: [Effect of scatter correction on quantification of myocardial SPECT and application to dual-energy acquisition using triple-energy window method].

  K Nakajima, M Matsudaira, M Yamada, J Taki, N Tonami, K Hisada
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  ABSTRACT: Triple-energy window (TEW) method is a simple and practical approach for correcting Compton scatter in single-photon emission tracer studies. The fraction of scatter correction, with a point source or 30 ml-syringe placed under the camera, was measured by the TEW method. The scatter fraction was 55% for 201Tl, 29% for 99mTc, 57% for 123I. Composite energy spectra were generated and separated by the TEW method. Combination of 99mTc and 201Tl was separated well, and 201Tl and 123I were separated within an error of 10%; whereas asymmetric photopeak energy window was necessary for separating 123I and 99mTc. By applying this method to myocardial SPECT study, the effect of scatter elimination was investigated in each myocardial wall by polar may and profile curve analysis. The effect of scatter was higher in the septum and the inferior wall. The count ratio relative to the anterior wall including scatter was 9% higher in 123I, 7-8% higher in 99mTc and 6% higher in 201Tl. Apparent count loss after scatter correction was 30% for 123I, 13% for 99mTc and 38% for 201Tl. Image contrast, as defined myocardium-to-left ventricular cavity count ratio, improved by scatter correction. Since the influence of Compton scatter was significant in cardiac planar and SPECT studies; the degree of scatter fraction should be kept in mind both in quantification and visual interpretation.
  Kaku igaku. The Japanese journal of nuclear medicine 09/1995; 32(9):959-67.
• Article: High-resolution cardiac SPET study using fanbeam collimators in infants.

  K Nakajima, J Taki, M Matsudaira, T Ichihara, T Ohno, K Hisada
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  ABSTRACT: High-resolution three-headed single photon emission computed tomography (SPET) equipped with fan-beam collimators was applied to myocardial perfusion imaging in infants aged from 1 to 11 months (n = 5). A tabletop designed specifically for infants was fixed on the SPET couch to reduce the radius of camera rotation to 13.2 cm. Significant improvement in resolution was achieved with the fan-beam collimators compared to parallel-hole high-resolution collimators. With the administration of approximately 37 MBq (26-44 MBq) 201Tl, 5 min acquisition time was possible for SPET imaging, which provided good image quality in all patients. Thus, a smaller administration dose is possible within a practical short acquisition time. High-resolution fan-beam SPET imaging can be a routine diagnostic method for heart disease in newborn babies and infants.
  Nuclear Medicine Communications 09/1992; 13(8):604-8. · 1.40 Impact Factor
• Source

  Available from: snmjournals.org

  Article: Dynamic acquisition with a three-headed SPECT system: application to technetium 99m-SQ30217 myocardial imaging.

  K Nakajima, J Taki, H Bunko, M Matsudaira, A Muramori, I Matsunari, K Hisada, T Ichihara
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  ABSTRACT: A method for SPECT data acquisition, "continuous repetitive rotation acquisition," was developed with a high-sensitivity three-headed SPECT system. The method was applied to the dynamic imaging of 99mTc-SQ30217, a new myocardial imaging agent. After acquisition and reconstruction of SPECT data every minute, projection images at arbitrary intervals were used for tomographic reconstruction to determine the best timing of SPECT imaging in 99mTc-SQ30217. Based on a comparison of several possible acquisition intervals, SPECT data acquisition within 9 min after injection is recommended because of high myocardial uptake (myocardium-to-lung ratio, 2.83 +/- 0.42 (mean +/- s.e.m.) at 3-6 min) and relatively low hepatic uptake (myocardium-to-liver ratio, 0.85 +/- 0.13 at 3-6 min). The rate constant of the clearance of 99mTc-SQ30217 from the myocardium obtained by SPECT was: k1 = 0.249 +/- 0.050 per min (average half-life = 2.8 min) and k2 = 0.012 +/- 0.004/min (average half-life = 58 min). The continuous repetitive rotation acquisition SPECT study appears useful for imaging SQ30217 with its rapidly changing myocardial distribution.
  Journal of Nuclear Medicine 07/1991; 32(6):1273-7. · 6.38 Impact Factor
• Article: [A three-headed SPECT system with high resolution and high sensitivity: application to myocardial imaging].

  K Nakajima, J Taki, K Hisada, M Matsudaira, H Bunko, T Ichihara, Y Fujiki, T Iwasaki, M Kubota
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  ABSTRACT: A three-headed single-photon emission computed tomography (SPECT) system was developed, and the fundamental SPECT performance and clinical applications were investigated. The full width at half maximum (FWHM) of the SPECT system is 10.8 mm at the center of rotation with a radius of 20 cm. In clinical applications, 201Tl myocardial images with the three-headed system demonstrated a distincter and thinner myocardium compared to those with the dual-headed system. The right ventricular wall was observed even in patients without right ventricular overload. Owing to both the increased sensitivity and resolution, the three-headed system has high performance capability in clinical use such as ECG-gating and dynamic studies.
  Kaku igaku. The Japanese journal of nuclear medicine 06/1990; 27(5):493-7.
• Article: [Evaluation of factor analysis using cardiac phantoms and mathematical models].

  K Nakajima, M Yamada, M Matsudaira, H Bunko, N Tonami, K Hisada, T Sato, M Hosoba, H Wani
  Kaku igaku. The Japanese journal of nuclear medicine 10/1986; 23(10):1423-34.
• Article: [Measurement of split glomerular filtration rate by fractional renal uptake of Tc-99m DTPA].

  T Aburano, T Takayama, K Nakajima, M Seto, N Tonami, K Hisada, M Yamada, Y Iida, M Kawamura, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 01/1986; 22(12):1781-7.
• Article: [Radionuclide study in the detection of varicocele in infertile men].

  T Takayama, T Aburano, M Seto, H Bunko, N Tonami, K Hisada, M Matsudaira, S Hirano, H Hisazumi
  Kaku igaku. The Japanese journal of nuclear medicine 12/1985; 22(11):1635-40.
• Article: [Clinical efficacy of SPECT (single photon emission computed tomography) for the detection of SOL (space occupying lesions) in the liver--evaluation by ROC analysis].

  T Aburano, K Nakajima, H Matsuda, A Tada, H Bunko, T Maeda, N Tonami, K Hisada, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 12/1984; 21(11):1413-20.
• Article: [Reproducibility and quantitativity of oblique-angle reconstruction in single photon emission computed tomography using TI-201 myocardial phantom].

  H Bunko, I Nanbu, H Seki, N Watanabe, H Sumiya, M Yamada, M Matsudaira, T Iida, A Tada, K Nakajima
  Kaku igaku. The Japanese journal of nuclear medicine 07/1984; 21(6):723-30.
• Article: [Hepatobiliary scintigraphy in segmental biliary obstruction].

  T Aburano, A Kuwajima, H Ishida, N Tonami, K Hisada, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 05/1984; 21(4):311-7.
• Article: [Furosemide-assisted diuretic 99mTc-DTPA renography in obstructive uropathy].

  T Aburano, A Tada, T Takayama, M Ohguchi, T Michigishi, N Tonami, K Hisada, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 04/1983; 20(2):205-13.
• Article: [Phantom experiment for quantitative evaluation of brain lesions using single photon emission computed tomography (ECT)].

  T Maeda, H Matsuda, K Hisada, M Yamada, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 06/1982; 19(4):541-4.
• Article: [Reproducibilities of radionuclide left ventricular analysis and studies on functional images of left ventricular performance (author's transl)].

  K Nakajima, H Bunko, A Tada, K Koizumi, T Maeda, N Tonami, K Hisada, M Yamada, S Matsumoto, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 01/1981; 17(10):1231-40.
• Article: [Value of FT1 (free thyroxine index) as an indicator thyroid functions in TRITAB and TETRATAB tests].

  H Bunko, A Kubota, K Hisada, M Matsudaira, S Matsumoto
  Kaku igaku. The Japanese journal of nuclear medicine 09/1977; 14(4):565-78.
• Article: [Extra-hepatosplenic distribution of 198 Au-colloid in diffuse hepatic diseases].

  T Aburano, Y Suzuki, K Hisada, M Matsudaira
  Kaku igaku. The Japanese journal of nuclear medicine 09/1974; 11(4):465-70.