| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Radiology, Institute of Medical Science, University of Tokyo, Tokyo
Department of Hepatoenteronephrology, National Children's Hospital, Tokyo
Department of Radiology, University Hospital, Mizonokuchi
Teikyo University School of Medicine, Kanagawa
Second Department of Internal Medicine and Department of Radiology, University of Tokyo, Tokyo, Japan
Correspondence: For correspondence or reprints contact: Yusuke Inoue, MD, Department of Radiology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
ABSTRACT
Correction for soft-tissue attenuation is required to evaluate absolute renal function by a camera-based method, and an estimate of renal depth and an attenuation coefficient are commonly used for attenuation correction. The first goal of this study was to develop formulas for the calculation of renal depth in both children and adults. The second goal was to optimize the attenuation coefficient for the estimation of renal accumulation of a 99mTc-labeled agent. Methods: Renal depth was measured by CT in 74 children and 232 adults and compared with the depth calculated using previously published equations. Multiple stepwise linear regression analysis was conducted using data from children and adults together, and new formulas to calculate renal depth were derived. Using the resulting equations, percentage renal uptake at 2–2.5 min was computed from 99mTc-diethylenetriamine pentaacetic acid (DTPA) renography in 40 children and 92 adults. Percentage renal uptake was assessed using various values of an attenuation coefficient, and an optimized attenuation coefficient was determined to maximize the correlation coefficient between percentage renal uptake and glomerular filtration rate (GFR) measured from 2 blood samples. Results: Although the previously published equations appeared to be acceptable in predicting adult renal depth, they substantially underestimated pediatric renal depth. Renal depth (D, cm) was shown by stepwise regression analysis to depend on the ratio of body weight (W, kg) to body height (H, cm) and was successfully calculated in both children and adults using the derived equations (right: D = 16.778 x W/H + 0.752; left: D = 16.825 x W/H + 0.397). The correlation coefficient between percentage renal uptake of 99mTc-DTPA and measured GFR varied substantially according to the attenuation coefficient used and was the highest (0.947) with an attenuation coefficient of 0.087/cm. Conclusion: The equations presented here enabled estimation of renal depth irrespective of the patient's age. Attenuation correction using these equations and the optimized attenuation coefficient appears to aid in evaluating renal accumulation and, consequently, renal function in both children and adults.
Key Words: renal function • attenuation correction • 99mTc-diethytenetriamine pentaacetic acid • renal depth • attenuation coefficient
This article has been cited by other articles:
|
|
 |
|
  L. I. Pelaez, L. A. Juncos, J. M. Stulak, L. O. Lerman, and J. C. Romero Non-invasive evaluation of bilateral renal regional blood flow and tubular dynamics during acute unilateral ureteral obstruction Nephrol. Dial. Transplant., January 1, 2005; 20(1): 83 - 88. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. D. Krier, E. L. Ritman, Z. Bajzer, J. C. Romero, A. Lerman, and L. O. Lerman Noninvasive measurement of concurrent single-kidney perfusion, glomerular filtration, and tubular function Am J Physiol Renal Physiol, October 1, 2001; 281(4): F630 - F638. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| JOURNAL OF NUCLEAR MEDICINE TECHNOLOGY | THE JOURNAL OF NUCLEAR MEDICINE |
