Korean J Radiol.  2003 Dec;4(4):224-233. 10.3348/kjr.2003.4.4.224.

Focal Hepatic Lesions: Contrast-Enhancement Patterns at Pulse-Inversion Harmonic US using a Microbubble Contrast Agent

• Kim EA
• Yoon KH
• Lee YH
• Kim HW
• Juhng SK
• Won JJ

• KMID: 1111251
• DOI: http://doi.org/10.3348/kjr.2003.4.4.224

Abstract

OBJECTIVE
To analyze the contrast-enhancement patterns obtained at pulseinversion harmonic imaging (PIHI) of focal hepatic lesions, and to thus determine tumor vascularity and the acoustic emission effect. MATERIALS AND METHODS: We reviewed pulse-inversion images in 90 consecutive patients with focal hepatic lesions, namely hepatocellular carcinoma (HCC) (n=43), metastases (n=30), and hemangioma (n=17). Vascular and delayed phase images were obtained immediately and five minutes following the injection of a microbubble contrast agent. Tumoral vascularity at vascular phase imaging and the acoustic emission effect at delayed phase imaging were each classified as one of four patterns. RESULTS: Vascular phase images depicted internal vessels in 93% of HCCs, marginal vessels in 83% of metastases, and peripheral nodular enhancement in 71% of hemangiomas. Delayed phase images showed inhomogeneous enhancement in 86% of HCCs; hypoechoic, decreased enhancement in 93% of metastases; and hypoechoic and reversed echogenicity in 65% of hemangiomas. Vascular and delayed phase enhancement patterns were associated with a specificity of 91% or greater, and 92% or greater, respectively, and with positive predictive values of 71% or greater, and 85% or greater, respectively. CONCLUSION: Contrast-enhancement patterns depicting tumoral vascularity and the acoustic emission effect at PIHI can help differentiate focal hepatic lesions.

Keyword

Liver, US; Liver, neoplasms; Liver neoplasms, US microbubbles; Ultrasound (US), contrast media; Ultrasound (US), harmonic study

MeSH Terms

Adult
Aged
Carcinoma, Hepatocellular/blood supply/*ultrasonography
Colon/pathology
Contrast Media/*administration & dosage
Diagnosis, Differential
Female
Hemangioma/blood supply/*ultrasonography
Human
Image Enhancement/*methods
Liver/pathology/ultrasonography
Liver Neoplasms/blood supply/secondary/*ultrasonography
Lung/pathology
Male
*Microbubbles
Middle Aged
Pancreas/pathology
Polysaccharides/administration & dosage/diagnostic use
Reproducibility of Results
Retrospective Studies
Sensitivity and Specificity
Stomach/pathology
Support, Non-U.S. Gov't

Figure

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  Fig. 1 The contrast-enhancement patterns observed at vascular phase pulse-inversion harmonic imaging of hepatic tumors.

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  Fig. 2 The contrast-enhancement patterns seen at delayed phase pulse-inversion harmonic imaging of hepatic tumors.

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  Fig. 3 Hepatocellular carcinoma showing the 'internal vessels' pattern during the vascular phase and 'inhomogeneous enhancement' during the delayed phase.A. Pulse-inversion harmonic US image before injection of the contrast agent depicts a hyperechoic mass (arrow).B, C. Vascular phase pulse-inversion harmonic US low-MI images obtained 15 sec (B) and 45 sec (C) after contrast injection depict the tumor's internal vessels (arrows).D. Delayed phase image (high MI) obtained five minutes after contrast injection demonstrates inhomogeneous enhancement (arrow) and the acoustic emission effect in hepatic parenchyma.

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  Fig. 4 Metastases from colon cancer showing 'marginal vessels' and 'hypoechoic, decreased enhancement'.A. Pulse-inversion harmonic US image obtained before contrast injection shows a hypoechoic mass (arrow).B, C. Vascular phase pulse-inversion harmonic US images (low MI) obtained 35 sec (B) and 54 sec (C) after contrast injection depict marginal tumor vessels (arrows) and some central vessels.D. Delayed phase image (high MI) shows a hypoechoic mass with decreased enhancement (arrow) compared to the acoustic emission effect of surrounding normal hepatic parenchyma.

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  Fig. 5 Hemangioma demonstrating 'peripheral nodular enhancement' and 'isoechoic, homogeneous enhancement' patterns.A, B, C. Vascular phase pulse-inversion harmonic US images obtained 24 sec (A), 38 sec (B) and 56 sec (C) after contrast injection depict peripheral nodular enhancement with progressive centripetal fill-in (arrows).D. Delayed phase image (high MI) demonstrates isoechoic, homogeneous enhancement (arrowheads), which is the same appearance as normal hepatic parenchyma.

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  Fig. 6 Metastasis from stomach cancer, exhibiting the 'hypoechoic, decreased enhancement' pattern on delayed phase image.A. Pulse-inversion harmonic US image obtained prior to contrast injection depicts a hypoechoic nodule (arrow).B. Delayed phase image (high MI) shows a hypoechoic mass with decreased enhancement (arrow) compared to homogenous bright echogenic hepatic parenchyma.

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  Fig. 7 Hemangioma demonstrating 'hypoechoic and reversed echogenicity' at the delayed phase.A. Conventional sonogram depicts a hyperechoic hepatic nodule (arrow).B. Delayed phase pulse-inversion harmonic image reveals a hypoechoic nodule with decreased enhancement compared to adjacent liver (arrow), and hypoechoic and reversed echogenicity at stimulated acoustic emission imaging.

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