HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lin, E. Articles by Treves, S. T. Search for Related Content PubMed Articles by Lin, E. Articles by Treves, S. T.

Reproducibility of Renal Length Measurements with ^99mTc-DSMA SPECT

Division of Nuclear Medicine, Department of Radiology, Children's Hospital, Harvard Medical School, Boston, Massachusetts

Renal length measurements are used in evaluating several abnormalities of the pediatric genitourinary tract. This study assesses reproducibility of renal length measurements obtained with ^99mTc–dimercaptosuccinic acid (DMSA) SPECT. Methods: The lengths of 98 kidneys of 51 children (age range, 1–16 y; mean age, 5.4 y) who underwent ^99mTc-DMSA SPECT were measured independently by 2 observers. Renal length was calculated by converting pixels between points at the superior and inferior renal margins on a summated coronal image to centimeters. Lengths were measured for kidneys as they appeared in situ and after realignment along their long axes. SPECT reconstruction, choice of display parameters, positioning of points used for measuring, and alignment were performed independently by each observer. Interobserver variability, interobserver correlation, and mean differences between observers' measurements (expressed as measurement of observer 2 – measurement of observer 1) were calculated. Results: Correlation between the observers' measurements was highly significant for both nonaligned and aligned studies (r = 0.95 and 0.97, respectively; both, P < 0.0001). Interobserver variability expressed as 1 SD was 3.6 mm for nonaligned studies and 2.8 mm for aligned studies. The mean difference between the 2 observers' measurements for nonaligned studies was 2.0 ± 4.8 mm (P < 0.0001) with a range of –11 to 14 mm. For aligned studies the mean difference between the 2 observers' measurements was –0.1 ± 4.0 mm (P = 0.88) with a range of –20 to 10 mm. Differences between observers were not dependent on absolute renal length (P = 0.68 for nonaligned studies; P = 0.40 for aligned studies). Conclusion: The variability in renal length measurements determined by ^99mTc-DMSA SPECT is similar to that reported previously using sonography. Because the interobserver differences in renal length are similar to annual renal growth rates during childhood, caution should be applied when incorporating renal length measurements determined by ^99mTc-DMSA SPECT into management algorithms. Additional studies are required to further establish interobserver variability, to assess intraobserver variability, and to evaluate means of improving standardization.

Key Words: kidney • SPECT • ^99mTc-DMSA

Received Oct. 4, 1999; revision accepted Feb. 16, 2000.

For correspondence or reprints contact: Leonard P. Connolly, MD, Division of Nuclear Medicine, Children's Hospital, 300 Longwood Ave., Boston, MA 02115.