title: [Proposal on new formulas for renal depth in the technetium-99m-mercaptoacetyltriglycine (MAG3) scintigraphy].
abstract: Recently, camera-based techniques to measure effective renal plasma flow (ERPF) have become more popular than single plasma sample techniques because camera-based measurements avoid the necessity of delayed plasma samples and in vitro techniques. The measurements of ERPF are used to estimate the clearance of technetium-99m-mercaptoacetyltriglycine (MAG3). However, camera-based techniques are dependent on an accurate estimate of renal depth to correct for soft-tissue attenuation. Then, new formulas for renal depth correction of technetium-99m-MAG3 clearance in place of Tønnesen's, M. Ito's, K. Itoh's, and Taylor's methods were tried to establish in this paper.
  
  
  METHODS
  Eleven hundred and seventy patients without any renal disease were objected. The data from measurement of renal depth using X-ray CT in supine position were analyzed statistically.
  
  
  RESULTS
  The depths of right kidney (Dr) and left kidney (Dl) were 7.33 +/- 1.27 and 7.07 +/- 1.27 cm. The correlation coefficients between Dr and height (H) body weight (W), body surface area (BSA: W0.425 x H0.725 x 0.007184 m2), age, and abdominal thickness (Ta) were 0.275, 0.709, 0.615, 0.087, and 0.743. The correlation coefficients between Dl and H, W, BSA, age, and Ta were 0.269, 0.732, 0.629, 0.029, and 0.812. Ta had best correlation with both Dr and Dl. The calculation formulas for Dr and Dl using Ta were as follows: Dr = 0.32 x Ta + 0.87 cm, and Dl = 0.36 x Ta - 0.08 cm. On the other hand, the multiplex calculation formulas of Dr or Dl with H, W, and Ta were as follows: Dr = 0.18Ta + 8.54 x (W/H) + 0.75 (r = 0.768), and Dl = 0.26Ta + 5.90 x (W/H)-0.16 (r = 0.823).
  
  
  CONCLUSIONS
  The new regression equations provide superior estimates of renal depth compared to conventional equations. Application of these new formulas into camera-based protocols to determine renal clearances may lead to more accurate measurements of ERPF using technetium-99m-MAG3 scintigraphy.
authors.affiliation: Department of Radiology, Fujigaoka Hospital of Showa University.
authors.forename: K
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Kuniyasu
authors.forename: Y
authors.initials: Y
authors.lastname: Niio
authors.forename: S
authors.initials: S
authors.lastname: Hasebe
authors.forename: M
authors.initials: M
authors.lastname: Yamada
authors.forename: H
authors.initials: H
authors.lastname: Shinohara
authors.forename: S
authors.initials: S
authors.lastname: Matsuoka
authors.forename: H
authors.initials: H
authors.lastname: Shima
authors.forename: M
authors.initials: M
authors.lastname: Obuchi
authors.forename: K
authors.initials: K
authors.lastname: Takizawa
authors.forename: M
authors.initials: M
authors.lastname: Honda
authors.forename: R
authors.initials: R
authors.lastname: Kawabe
authors.forename: J
authors.initials: J
authors.lastname: Kuwayama
authors.forename: S
authors.initials: S
authors.lastname: Iwasaki
authors.forename: T
authors.initials: T
authors.lastname: Ideura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007668:Kidney / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D017263:Technetium Tc 99m Mertiatide; D014057:Tomography, X-Ray Computed
chemical_list: D017263:Technetium Tc 99m Mertiatide