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The Combined Effect of Multidetector-Row Computed Tomographic Tube Voltage, Tube Current, and Image Reconstruction Algorithm on the Detection of Pneumothorax After Intervention

Ferreira Botelho, Marcos P. MD; Seyal, Adeel R. MD; Gonzalez-Guindalini, Fernanda D. MD; Harmath, Carla B. MD; Galizia, Mauricio S. MD; Yaghmai, Vahid MD

Journal of Computer Assisted Tomography: July/August 2014 - Volume 38 - Issue 4 - p 591–596
doi: 10.1097/RCT.0b013e3182ab2a71
Thoracic Imaging

Objectives The objective of the study was to determine the lowest multidetector-row computed tomographic radiation dose parameters for the detection of pneumothorax after thoracic intervention.

Materials and Methods An anthropomorphic chest phantom containing pneumothoraces was imaged with different tube voltages (80, 100, and 120 kV[p]) and tube currents (10, 20, 40, 75, and 110 mAs). The images were reconstructed with both filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Two blinded radiologists scored images independently for the presence or absence of pneumothorax. Effective dose, image noise, contrast-to-noise ratio, and signal-to-noise ratio were recorded.

Results At radiation dose below 0.48 mSv, sensitivity for the detection of pneumothorax decreased in both reconstruction algorithms (80% for FBP vs 83% for IR; P > 0.05). Interobserver agreement was good (k = 0.78). The IR data sets showed lower image noise as well as higher signal-to-noise ratio and contrast-to-noise ratio when compared with FBP on all acquisition parameters (P < 0.0001).

Conclusions Very low computed tomographic dose parameters may be suitable for confident detection of small pneumothoraces after intervention.

From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University-Feinberg School of Medicine, Chicago, IL.

Received for publication September 13, 2013; accepted October 17, 2013.

Reprints: Vahid Yaghmai, MD, Department of Radiology, Northwestern Memorial Hospital, Northwestern University-Feinberg School of Medicine, 676 N St Clair St, Suite 800, Chicago, IL 60611 (e-mail:

Marcos P. Ferreira Botelho, MD, Adeel R. Seyal, MD, and Fernanda D. Gonzalez-Guindalini, MD, were supported by educational grant from Siemens Healthcare. For the remaining authors, no conflicts of interest were declared.

© 2014 by Lippincott Williams & Wilkins