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Detection of hepatic VX2 tumors in rabbits: comparison of conventional US and phase-inversion harmonic US during the liver-specific late phase of contrast enhancement.

Lee JM, Youk JH, Lee YH, Kim YK, Kim CS, Li CA - Korean J Radiol (2003 Apr-Jun)

Bottom Line: Following sacrifice of the animals, pathologic analysis was performed and the reference standard thus obtained.CE-PIHI demonstrated marked hepatic parenchymal enhancement in all rabbits.Conventional US correctly detected 18 of the 52 (34.6%), while PIHI detected 35 (67.3%) (p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Chonbuk National University Hospital, Jeonju, Chonbuk, Korea. leejm@radcom.snu.ac.kr

ABSTRACT

Objective: To compare phase-inversion sonography during the liver-specific phase of contrast enhancement using a microbubble contrast agent with conventional B-mode sonography for the detection of VX2 liver tumors.

Materials and methods: Twenty-three rabbits, 18 of which had VX2 liver tumor implants, received a bolus injection of 0.6 g of Levovist (200 mg/ml). During the liver-specific phase of this agent, they were evaluated using both conventional sonography and contrast-enhanced phase-inversion harmonic imaging (CEPIHI). Following sacrifice of the animals, pathologic analysis was performed and the reference standard thus obtained. The conspicuity, size and number of the tumors before and after contrast administration, as determined by a sonographer, were compared between the two modes and with the pathologic findings.

Results: CE-PIHI demonstrated marked hepatic parenchymal enhancement in all rabbits. For VX2 tumors detected at both conventional US and CE- PIHI, conspicuity was improved by contrast-enhanced PIHI. On examination of gross specimens, 52 VX2 tumors were identified. Conventional US correctly detected 18 of the 52 (34.6%), while PIHI detected 35 (67.3%) (p < 0.05). In particular, conventional US detected only three (8.3%) of the 36 tumors less than 10 mm in diameter, but CE-PIHI detected 19 such tumors (52.8%) (p < 0.05).

Conclusion: Compared to conventional sonography, PIHI performed during the liver-specific phase after intravenous injection of Levovist is markedly better at detecting VX2 liver tumors.

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A. Unenhanced subcostal transverse sonogram of rabbit liver depicts a heterogeneous isoechoic lesion (arrows).B. Contrast-enhanced transverse phase-inversion US image obtained slightly inferior to the unenhanced image (A) reveals three nonenhancing foci measuring 2-12 mm in diameter. Two additional lesions (arrows) are identified, and their conspicuity is much greater than at unenhanced conventional imaging (A).C. Transverse section of the liver reveals five tumors at the same location. Compared to B, two additional lesions (arrows) less than 5 mm in diameter are apparent.
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Figure 2: A. Unenhanced subcostal transverse sonogram of rabbit liver depicts a heterogeneous isoechoic lesion (arrows).B. Contrast-enhanced transverse phase-inversion US image obtained slightly inferior to the unenhanced image (A) reveals three nonenhancing foci measuring 2-12 mm in diameter. Two additional lesions (arrows) are identified, and their conspicuity is much greater than at unenhanced conventional imaging (A).C. Transverse section of the liver reveals five tumors at the same location. Compared to B, two additional lesions (arrows) less than 5 mm in diameter are apparent.

Mentions: On examination of gross specimens, 52 VX2 tumors were identified: 22 were less than 5 mm in diameter, 14 were between 5 and 9 mm, and 15 were 10 mm or larger. In 15 of the 18 rabbits (83.3%) in which hepatic VX2 tumors were seen at pathologic examination, conventional imaging also revealed their presence (Table 1). In 61.1% of the rabbits (11/18), more VX2 tumors were detected at PIHI with Levovist injection than at conventional US imaging (Fig. 3). Of the 52 VX2 tumors, conventional US imaging detected only 18 (34.6%), but PIHI with contrast injection detected 35 (67.3%) (p < 0.05). In addition, conventional US and CE-PIHI revealed the presence of VX2 tumors in 15 (83.3%) and 18 rabbits (100%), respectively, with positive findings. Thus, sensitivity to the presence or absence of hepatic VX2 tumor increased from 83.3% with conventional US imaging to 100% with contrast-enhanced PIHI (p > 0.05). In three rabbits with false-negative findings at conventional imaging, four tumors (two less than 5 mm in diameter, two between 5 and 9 mm) were found at pathologic examination; contrast-enhanced PIHI detected three of four nodules (Fig. 2). Furthermore, contrast-enhanced PIHI detected significantly smaller VX2 tumors than did conventional US imaging (p < 0.05): the latter depicted 19 of 36 tumors less than 10 mm in diameter (52.8%), while the former revealed only three such tumors (8.3%) (Table 1).


Detection of hepatic VX2 tumors in rabbits: comparison of conventional US and phase-inversion harmonic US during the liver-specific late phase of contrast enhancement.

Lee JM, Youk JH, Lee YH, Kim YK, Kim CS, Li CA - Korean J Radiol (2003 Apr-Jun)

A. Unenhanced subcostal transverse sonogram of rabbit liver depicts a heterogeneous isoechoic lesion (arrows).B. Contrast-enhanced transverse phase-inversion US image obtained slightly inferior to the unenhanced image (A) reveals three nonenhancing foci measuring 2-12 mm in diameter. Two additional lesions (arrows) are identified, and their conspicuity is much greater than at unenhanced conventional imaging (A).C. Transverse section of the liver reveals five tumors at the same location. Compared to B, two additional lesions (arrows) less than 5 mm in diameter are apparent.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2698070&req=5

Figure 2: A. Unenhanced subcostal transverse sonogram of rabbit liver depicts a heterogeneous isoechoic lesion (arrows).B. Contrast-enhanced transverse phase-inversion US image obtained slightly inferior to the unenhanced image (A) reveals three nonenhancing foci measuring 2-12 mm in diameter. Two additional lesions (arrows) are identified, and their conspicuity is much greater than at unenhanced conventional imaging (A).C. Transverse section of the liver reveals five tumors at the same location. Compared to B, two additional lesions (arrows) less than 5 mm in diameter are apparent.
Mentions: On examination of gross specimens, 52 VX2 tumors were identified: 22 were less than 5 mm in diameter, 14 were between 5 and 9 mm, and 15 were 10 mm or larger. In 15 of the 18 rabbits (83.3%) in which hepatic VX2 tumors were seen at pathologic examination, conventional imaging also revealed their presence (Table 1). In 61.1% of the rabbits (11/18), more VX2 tumors were detected at PIHI with Levovist injection than at conventional US imaging (Fig. 3). Of the 52 VX2 tumors, conventional US imaging detected only 18 (34.6%), but PIHI with contrast injection detected 35 (67.3%) (p < 0.05). In addition, conventional US and CE-PIHI revealed the presence of VX2 tumors in 15 (83.3%) and 18 rabbits (100%), respectively, with positive findings. Thus, sensitivity to the presence or absence of hepatic VX2 tumor increased from 83.3% with conventional US imaging to 100% with contrast-enhanced PIHI (p > 0.05). In three rabbits with false-negative findings at conventional imaging, four tumors (two less than 5 mm in diameter, two between 5 and 9 mm) were found at pathologic examination; contrast-enhanced PIHI detected three of four nodules (Fig. 2). Furthermore, contrast-enhanced PIHI detected significantly smaller VX2 tumors than did conventional US imaging (p < 0.05): the latter depicted 19 of 36 tumors less than 10 mm in diameter (52.8%), while the former revealed only three such tumors (8.3%) (Table 1).

Bottom Line: Following sacrifice of the animals, pathologic analysis was performed and the reference standard thus obtained.CE-PIHI demonstrated marked hepatic parenchymal enhancement in all rabbits.Conventional US correctly detected 18 of the 52 (34.6%), while PIHI detected 35 (67.3%) (p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Diagnostic Radiology, Chonbuk National University Hospital, Jeonju, Chonbuk, Korea. leejm@radcom.snu.ac.kr

ABSTRACT

Objective: To compare phase-inversion sonography during the liver-specific phase of contrast enhancement using a microbubble contrast agent with conventional B-mode sonography for the detection of VX2 liver tumors.

Materials and methods: Twenty-three rabbits, 18 of which had VX2 liver tumor implants, received a bolus injection of 0.6 g of Levovist (200 mg/ml). During the liver-specific phase of this agent, they were evaluated using both conventional sonography and contrast-enhanced phase-inversion harmonic imaging (CEPIHI). Following sacrifice of the animals, pathologic analysis was performed and the reference standard thus obtained. The conspicuity, size and number of the tumors before and after contrast administration, as determined by a sonographer, were compared between the two modes and with the pathologic findings.

Results: CE-PIHI demonstrated marked hepatic parenchymal enhancement in all rabbits. For VX2 tumors detected at both conventional US and CE- PIHI, conspicuity was improved by contrast-enhanced PIHI. On examination of gross specimens, 52 VX2 tumors were identified. Conventional US correctly detected 18 of the 52 (34.6%), while PIHI detected 35 (67.3%) (p < 0.05). In particular, conventional US detected only three (8.3%) of the 36 tumors less than 10 mm in diameter, but CE-PIHI detected 19 such tumors (52.8%) (p < 0.05).

Conclusion: Compared to conventional sonography, PIHI performed during the liver-specific phase after intravenous injection of Levovist is markedly better at detecting VX2 liver tumors.

Show MeSH
Related in: MedlinePlus