In noncirrhotic patients, the hypoechoic pattern in portal and sinusoidal phase (rapid wash-out) or the markedly hypoechoic or anechoic pattern in sinusoidal phase (marked late wash-out) showed a sensitivity, specificity, and accuracy of 97%, 100%, and 98%, respectively, for the diagnosis of malignancy [37]. Variant 3: Indeterminate, greater than 1 cm liver lesion on initial imaging with US. Known history of an extrahepatic malignancy. CT Abdomen In patients with a history of primary malignancy, contrast-enhanced CT can differentiate between metastases and benign lesions with 74% accuracy [40]. Specifically, in patients with a history of colon cancer, lesion characterization on contrast-enhanced CT is correct in 77% of cases [41]. When metastases are suspected based on US, the sensitivity and specificity of contrast-enhanced CT for detection of metastases are 88% and 17%, respectively [42]. In patients with hypervascular liver metastases, addition of noncontrast CT can improve the confidence level for lesion characterization by 4% to 15%; however, it does not change the diagnostic accuracy [43]. The addition of noncontrast CT can increase sensitivity for breast cancer metastases by 5% to 23% but does not improve sensitivity for melanoma metastases [44]. Sensitivity of noncontrast CT alone is 61% to 100% for breast cancer metastases, 62% to 100% for melanoma metastases, and 17% to 88% for NET metastases [44]. In comparison, contrast- enhanced CT has sensitivity of 77% to 95% for breast cancer metastases, 86% to 100% for melanoma metastases, and 44% to 77% for NET metastases [44,45]. FDG-PET/CT Skull Base to Mid-Thigh In patients with a history of primary malignancy, FDG-PET/CT can differentiate between malignant and benign lesions with an accuracy of 75% [40].
Liver Lesion Initial Characterization. In noncirrhotic patients, the hypoechoic pattern in portal and sinusoidal phase (rapid wash-out) or the markedly hypoechoic or anechoic pattern in sinusoidal phase (marked late wash-out) showed a sensitivity, specificity, and accuracy of 97%, 100%, and 98%, respectively, for the diagnosis of malignancy [37]. Variant 3: Indeterminate, greater than 1 cm liver lesion on initial imaging with US. Known history of an extrahepatic malignancy. CT Abdomen In patients with a history of primary malignancy, contrast-enhanced CT can differentiate between metastases and benign lesions with 74% accuracy [40]. Specifically, in patients with a history of colon cancer, lesion characterization on contrast-enhanced CT is correct in 77% of cases [41]. When metastases are suspected based on US, the sensitivity and specificity of contrast-enhanced CT for detection of metastases are 88% and 17%, respectively [42]. In patients with hypervascular liver metastases, addition of noncontrast CT can improve the confidence level for lesion characterization by 4% to 15%; however, it does not change the diagnostic accuracy [43]. The addition of noncontrast CT can increase sensitivity for breast cancer metastases by 5% to 23% but does not improve sensitivity for melanoma metastases [44]. Sensitivity of noncontrast CT alone is 61% to 100% for breast cancer metastases, 62% to 100% for melanoma metastases, and 17% to 88% for NET metastases [44]. In comparison, contrast- enhanced CT has sensitivity of 77% to 95% for breast cancer metastases, 86% to 100% for melanoma metastases, and 44% to 77% for NET metastases [44,45]. FDG-PET/CT Skull Base to Mid-Thigh In patients with a history of primary malignancy, FDG-PET/CT can differentiate between malignant and benign lesions with an accuracy of 75% [40].