Hepatic tumor detection: MR imaging and conventional US versus pulse-inversion harmonic US of NC100100 during its reticuloendothelial system-specific phase.
OBJECTIVE
To compare conventional ultrasonography (US) and magnetic resonance (MR) imaging with contrast agent-enhanced US for detection of VX-2 liver tumors in rabbits.


METHODS
Conventional gray-scale liver US was performed in 65 rabbits, 38 of which had VX-2 hepatic tumor implants. Twenty minutes after contrast agent injection, gray-scale pulse-inversion harmonic US images of the liver-specific phase were obtained. Following sacrifice of the animals, T1- and T2-weighted MR imaging was performed at 4-mm intervals. Pathologic analysis was performed as the reference standard. The capability of each imaging modality to correctly depict tumor presence or absence and the number of tumors was compared.


RESULTS
Conventional US correctly depicted the presence or absence of tumors in 54 rabbits, for an accuracy of 83%, sensitivity of 71%, and specificity of 100%. With contrast-enhanced US, accuracy increased to 92% (60 correct cases); sensitivity, to 87%; and specificity, to 100%. MR imaging facilitated 56 correct diagnoses, for an accuracy of 86%, sensitivity of 82%, and specificity of 93%. There was a marginally significant difference between US with and US without contrast agent (P =.07) but not between MR imaging and contrast-enhanced US (P > or = .34). When the numbers of correctly detected tumors were compared, contrast-enhanced US performed significantly better than MR imaging (P =.02) and conventional US (P =.04).


CONCLUSIONS
There was no significant difference between contrast-enhanced US and MR imaging in the detection of hepatic tumors, whereas contrast-enhanced US had the highest accuracy (92%) of the three modalities studied.
Forsberg
Flemming
F
Department of Radiology, Division of Ultrasound, Thomas Jefferson University Hospital, Suite 763J, Main Bldg, 132 S 10th St, Philadelphia, PA 19107, USA. forsberg@esther.rad.tju.edu
Piccoli
Catherine W
CW
Liu
Ji-Bin
JB
Rawool
Nandkumar M
NM
Merton
Daniel A
DA
Mitchell
Donald G
DG
Goldberg
Barry B
BB
D000818:Animals; D003287:Contrast Media; D005290:Ferric Compounds; D007501:Iron; D007728:Kupffer Cells / Q000000981:diagnostic imaging*; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D010087:Oxides; D011817:Rabbits; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
D003287:Contrast Media; D005290:Ferric Compounds; D010087:Oxides; C069727:Sonazoid; D007501:Iron