title: Decreased detection of hypovascular liver tumors with MDCT in obese patients: a phantom study.
abstract: OBJECTIVE
  The purpose of this article is to assess the impact of large patient size on the detection of hypovascular liver tumors with MDCT and the effect of a noise filter on image quality and lesion detection in obese patients.
  
  
  METHODS
  A liver phantom with 45 hypovascular tumors (diameters of 5, 10, and 15 mm) was placed into two water containers mimicking intermediate and large patients. The containers were scanned with a 64-MDCT scanner. The CT dataset from the large phantom was postprocessed using a noise filter. The image noise was measured and the contrast-to-noise ratio (CNR) of the tumors was calculated. Tumor detection was independently performed by three radiologists in a blinded fashion.
  
  
  RESULTS
  The application of the noise filter in the large phantom yielded a reduction of image noise by 42% (p < 0.0001). The CNR values of the tumors in the nonfiltered and filtered large phantom were lower than that in the intermediate phantom (p < 0.05). In the non-filtered and filtered large phantom, 25% and 19% fewer tumors, respectively, were detected on average compared with the intermediate phantom (p < 0.01).
  
  
  CONCLUSIONS
  The risk of missing hypovascular liver tumors with CT is substantially increased in large patients. A noise filter improves image quality in obese patients.
authors: Institute of Diagnostic, Interventional, and Pediatric Radiology, University Hospital Berne, University of Berne, Freiburgstrasse, CH-3010 Berne, Switzerland. sschindera@aol.com
authors: Sebastian T
authors: ST
authors: Schindera
authors: Jaled Charimo
authors: JC
authors: Torrente
authors: Thomas D
authors: TD
authors: Ruder
authors: Hanno
authors: H
authors: Hoppe
authors: Daniele
authors: D
authors: Marin
authors: Rendon C
authors: RC
authors: Nelson
authors: Zsolt
authors: Z
authors: Szucs-Farkas