Furthermore, for lesions not seen on grayscale US, the success rate for CEUS-guided biopsy can be as high as 88% to 96% [24,25]. US fusion with CT or MRI can be used for percutaneous biopsy of lesions with poor sonographic conspicuity with a 96% technical success rate [25]. Lesions which are isointense on CT can also present a challenge for CT-guided biopsy; however, use of anatomic landmarks or IV contrast can achieve accuracy of 96% to 98% [26]. Image-guided biopsies carry a risk of postbiopsy bleeding, which may be as high as 9% to 12%, particularly with hypervascular lesions [27,28]. In addition, a very small risk of needle-track seeding exists. RBC Scan Abdomen and Pelvis There is no relevant literature to support the use of a Tc-99m RBC scan in this clinical scenario. Liver Spleen Scan There is no relevant literature to support the use of a Tc-99m sulfur colloid scan in this clinical scenario. US Abdomen with Contrast Depending on the appearance of the lesion on the initial US, CEUS may be performed for lesion characterization. CEUS can differentiate between malignant and benign lesions in 90% of lesions [48]. Diagnostic accuracy of CEUS for metastases is 83% compared with 76% for MRI with extracellular contrast agent [35]. 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 4: Indeterminate, greater than 1 cm liver lesion on initial imaging with CT (noncontrast or single- phase) or noncontrast MRI. 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].
Liver Lesion Initial Characterization. Furthermore, for lesions not seen on grayscale US, the success rate for CEUS-guided biopsy can be as high as 88% to 96% [24,25]. US fusion with CT or MRI can be used for percutaneous biopsy of lesions with poor sonographic conspicuity with a 96% technical success rate [25]. Lesions which are isointense on CT can also present a challenge for CT-guided biopsy; however, use of anatomic landmarks or IV contrast can achieve accuracy of 96% to 98% [26]. Image-guided biopsies carry a risk of postbiopsy bleeding, which may be as high as 9% to 12%, particularly with hypervascular lesions [27,28]. In addition, a very small risk of needle-track seeding exists. RBC Scan Abdomen and Pelvis There is no relevant literature to support the use of a Tc-99m RBC scan in this clinical scenario. Liver Spleen Scan There is no relevant literature to support the use of a Tc-99m sulfur colloid scan in this clinical scenario. US Abdomen with Contrast Depending on the appearance of the lesion on the initial US, CEUS may be performed for lesion characterization. CEUS can differentiate between malignant and benign lesions in 90% of lesions [48]. Diagnostic accuracy of CEUS for metastases is 83% compared with 76% for MRI with extracellular contrast agent [35]. 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 4: Indeterminate, greater than 1 cm liver lesion on initial imaging with CT (noncontrast or single- phase) or noncontrast MRI. 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].