Katsutoshi Sugimoto, Presenter: Nothing to Disclose

Junji Shiraishi, Abstract Co-Author: License agreement, Riverain Medical License agreement, MEDIAN Technologies Research support, Riverain Medical Research support, Totoku Electric Co, Ltd

Kazuhiro Saito MD, Abstract Co-Author: Nothing to Disclose

Fuminori Moriyasu MD, PhD, Abstract Co-Author: Nothing to Disclose

Kunio Doi PhD, Abstract Co-Author: Shareholder, Hologic, Inc License agreement, Hologic, Inc License agreement, Deus Technologies, LLC License agreement, Riverain Medical License agreement, Mitsubishi Corporation License agreement, MEDIAN Technologies License agreement, General Electric Company License agreement, Toshiba Corporation Research support, Deus Technologies, LLC Research support, DuPont Research support, Elbit Medical Imaging Ltd Research support, Fuji Photo Film Co, Ltd Research support, General Electric Company Research support, Hitachi, Ltd Research support, Eastman Kodak Company Research support, Konica Minolta Group Research support, Mitaya Manufacturing Co, Ltd Research support, Mitsubishi Corporation Research support, Koninklijke Philips Electronics NV Research support, Hologic, Inc Research support, Riverain Medical Research support, Seiko Corporation Research support, Siemens AG Research support, 3M Company Research support, Toshiba Corporation

To compare conventional B-mode ultrasonography (US) alone with the combination of conventional B-mode US and contrast material-enhanced (SonazoidTM ) late-phase pulse-inversion US for the detection of hepatic metastases by using a jackknife free-response receiver operating characteristic (JAFROC) analysis.

This study was IRB-approved with written informed consent. Twenty-seven patients with 55 hepatic metastases and 6 patients without hepatic metastasis underwent conventional B-mode US and contrast-enhanced US in the liver-specific phases of SonazoidTM. We used the diagnoses established by contrast-enhanced multi-detector row computed tomography as the standard of reference. All US scanning was performed by an experienced radiologist with a routine clinical procedure. All scanning data were archived with digital cine clips. A Windows-PC based review system, which could display pairs of cine clips for B-mode and contrast-enhanced US side by side, was developed for off-site observer study. Seven radiologists interpreted each case individually first conventional B-mode only, and then the combination with contrast-enhanced US by identifying locations of possible candidates for hepatic metastasis with their confidence ratings. The figure of merit (FOM) values, sensitivity, and false-positives per case were estimated for B-mode US alone, and for the combination of conventional B-mode and contrast-enhanced US. The analysis of variances for multi-reader-multi-case matrix of pseudo FOM values was used for testing statistically significant difference between two modes of interpretations.

For all readers, the sensitivities of the combined US imaging (mean 76.4%) were clearly improved from that of conventional US alone (mean 42.1%) by reducing an average number of false positives form 1.1 to 0.5 per case. In the jackknife analysis, there was a statistically significant difference between mean FOM values for the combined imaging (0.79) and for conventional US alone (0.44, P < .00001).

The combination of conventional US and contrast-enhanced US showed higher accuracy in the detection of hepatic metastases than conventional US alone.

In the evaluation of patients with suspected hepatic metastases, US examination must be performed with contrast administration.

Sugimoto, K, Shiraishi, J, Saito, K, Moriyasu, F, Doi, K, Improved Detection of Hepatic Metastases with Contrast-enhanced Low Mechanical-Index Pulse Subtraction Ultrasonography during the Liver-Specific Phase of Sonazoid: Observer Performance Study with JAFROC Analysis.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6010078.html