Detection of liver metastases in cancer patients with geographic fatty infiltration of the liver: the added value of contrast-enhanced sonography

Abstract

Purpose: The aim of this study is to assess the role of contrast-enhanced ultrasonography (CEUS) in the detection of liver metastases in cancer patients with geographic liver fatty deposition on greyscale ultrasonography (US).

Methods: Thirty-seven consecutive cancer patients (24 women and 13 men; age, 33 to 80 years; mean, 58.1 years) with geographic liver fatty deposition, but without any detectable focal liver lesion on greyscale US, underwent sulphur hexafluoride-enhanced US. Two readers reported by consensus the presence, size, and location of any detected lesion. All patients underwent magnetic resonance imaging (MRI) as a confirmatory study. Sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy were calculated.

Results: Seven focal liver lesions (size, 4 to 10 mm; mean, 6.1 mm) were detected in 4/37 patients (10.8%): four metastases (size, 5 to 10 mm; mean, 6.7 mm) were detected both by CEUS and MRI, with one hemangioma and two cysts (size range, 4 to 6 mm; mean, 5.3 mm) detected by MRI only. In 1/37 patients (2.7%), CEUS misdiagnosed geographic fatty change as three metastases. In 32/37 patients (86.5%), no lesions were detected. Sensitivity, specificity, PPV, NPV, and accuracy of CEUS were 100% (95% confidence Interval [CI], 1.000 to 1.000), 97.1% (95% CI, 0.914 to 1.027), 75%, 100%, and 97.3%, respectively. No statistically significant differences were found between CEUS and MRI in the detection of focal liver lesions (P=0.480), whereas both of them performed better than baseline US (P<0.001).

Conclusion: CEUS improves the detection of liver metastases in cancer patients with geographic liver fatty deposition on greyscale US.

Keywords: Contrast media; Fatty liver; Liver diseases; Liver neoplasms; Neoplasm metastasis; Ultrasonography.

Fig. 1.. A 53-year-old woman affected by breast cancer.

A, B. Oblique ultrasonography of the right hepatic lobe shows geographic fatty infiltration of the liver, but no evidence of any focal liver lesion either before (A) or after contrast medium injection (B) (right side). C, D. An unenhanced T1-weighted “out of phase” magnetic resonance imaging image confirms geographic fatty change of the liver, but absence of lesions by showing a clear-cut inhomogeneous signal drop-out of hepatic parenchyma, in comparison with the “in phase” T1-weighted image (D).

Fig. 2.. Liver metastasis in a 70-year-old man (Table 3, patient 2).

A. Parasagittal B-mode ultrasonography of the left lobe (right side, arrows) shows geographic fatty change of the liver but no evidence of any focal liver lesion whereas contrast-enhanced ultrasonography (left side) depicts a 0.5-cm-sized hypoechoic focal liver lesion in segment II during extended portal-venous phase (calipers). B-D. “In phase” (B) and “out of phase” (C) unenhanced magnetic resonance (MR) T1-weighted images confirm geographic fatty infiltration of the liver and contrast-enhanced MR T1-weighted image in the portal-venous phase reveals the hypovascular metastasis (D) (arrow).

Fig. 3.. Hemangioma in a 47-year-old woman (Table 3, patient 4).

A. Transverse ultrasonography of the left liver lobe shows geographic fatty change without any detectable focal liver lesion either at B-mode ultrasonography (left side, arrows) or contrast-enhanced ultrasonography (right side). B, C. “In phase” (B) and “out of phase” (C) unenhanced magnetic resonance (MR) T1-weighted images confirm geographic fatty infiltration of the liver and reveal a hypointense 6-mm-sized lesion in segment II (arrow). D, E. The lesion is hyperintense on heavily T2-weighted MR image (D) and shows homogeneous contrast-enhancement on T1-weighted MR image in the late phase (E) (arrows).

Fig. 4.. A 63-year-old woman affected by endometrial cancer.

A. Parasagittal baseline ultrasonography shows geographic fatty change in the left hepatic lobe (arrow). B. Contrast-enhanced ultrasonography shows a hypovascular area during the extended portal-venous phase (right side, arrow) misdiagnosed as metastasis. C, D. Unenhanced magnetic resonance image confirms geographic fatty change of the liver by depicting multiple hyperintense areas (arrows) of hepatic parenchyma on T1-weighted "in-phase" image (C) with a clear-cut signal drop-out in T1-weighted “out of phase” image (arrows) (D).