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. 2015 Feb;45(2):181-7.
doi: 10.1007/s00247-014-3109-7. Epub 2014 Jul 5.

Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

Ryne A Didier  1 , Petra L Vajtai, Katharine L Hopkins
Affiliations

Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

Ryne A Didier et al. Pediatr Radiol. 2015 Feb.

Abstract

Background: Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated.

Objective: This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDIvol).

Materials and methods: Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDIvol. Reduced CTDIvol was achieved primarily by reductions in effective tube current-time product (mAseff) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDIvol, size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared.

Results: Between groups A and B, mean CTDIvol was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B.

Conclusion: Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDIvol and SSDE by nearly half as compared to the hospital's traditional weight-based protocols.

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Conflict of interest statement

Conflicts of interest None

Figures

Fig. 1
Fig. 1
Axial (a) and coronal (b) contrast-enhanced CT images of the pelvis in a 15-year-old boy show a 14-mm diameter appendix (arrow) with periappendiceal fat stranding, indicating presence of inflammation (group A, traditional pediatric weight-based protocol with filtered back projection reconstruction; 3 mm axial and coronal section thickness; CTDIvol 16 mGy; SSDE 23 mGy). Axial (c) and coronal (d) contrast-enhanced CT images of the pelvis in a 12-year-old boy show a 14-mm diameter, fluid-filled appendix (arrow) and periappendiceal inflammation (group B, filtered back projection/iterative reconstruction technique blend; 3 mm axial and coronal section thickness; CTDIvol 3 mGy; SSDE 5 mGy). Surgical pathology confirmed appendicitis in both patients
Fig. 1
Fig. 1
Axial (a) and coronal (b) contrast-enhanced CT images of the pelvis in a 15-year-old boy show a 14-mm diameter appendix (arrow) with periappendiceal fat stranding, indicating presence of inflammation (group A, traditional pediatric weight-based protocol with filtered back projection reconstruction; 3 mm axial and coronal section thickness; CTDIvol 16 mGy; SSDE 23 mGy). Axial (c) and coronal (d) contrast-enhanced CT images of the pelvis in a 12-year-old boy show a 14-mm diameter, fluid-filled appendix (arrow) and periappendiceal inflammation (group B, filtered back projection/iterative reconstruction technique blend; 3 mm axial and coronal section thickness; CTDIvol 3 mGy; SSDE 5 mGy). Surgical pathology confirmed appendicitis in both patients
Fig. 1
Fig. 1
Axial (a) and coronal (b) contrast-enhanced CT images of the pelvis in a 15-year-old boy show a 14-mm diameter appendix (arrow) with periappendiceal fat stranding, indicating presence of inflammation (group A, traditional pediatric weight-based protocol with filtered back projection reconstruction; 3 mm axial and coronal section thickness; CTDIvol 16 mGy; SSDE 23 mGy). Axial (c) and coronal (d) contrast-enhanced CT images of the pelvis in a 12-year-old boy show a 14-mm diameter, fluid-filled appendix (arrow) and periappendiceal inflammation (group B, filtered back projection/iterative reconstruction technique blend; 3 mm axial and coronal section thickness; CTDIvol 3 mGy; SSDE 5 mGy). Surgical pathology confirmed appendicitis in both patients
Fig. 1
Fig. 1
Axial (a) and coronal (b) contrast-enhanced CT images of the pelvis in a 15-year-old boy show a 14-mm diameter appendix (arrow) with periappendiceal fat stranding, indicating presence of inflammation (group A, traditional pediatric weight-based protocol with filtered back projection reconstruction; 3 mm axial and coronal section thickness; CTDIvol 16 mGy; SSDE 23 mGy). Axial (c) and coronal (d) contrast-enhanced CT images of the pelvis in a 12-year-old boy show a 14-mm diameter, fluid-filled appendix (arrow) and periappendiceal inflammation (group B, filtered back projection/iterative reconstruction technique blend; 3 mm axial and coronal section thickness; CTDIvol 3 mGy; SSDE 5 mGy). Surgical pathology confirmed appendicitis in both patients
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