Assessment of the Vascularization of Neuroendocrine Tumors by Stimulated Acoustic Emission of SH U 508A Ultrasound Contrast Agent and Color or Power Doppler Sonography

Abstract
Ricke J, Lopez Hänninen E, Amthauer H, Lemke A, Felix R.Assessment of the vascularization of neuroendocrine tumors by stimulated acoustic emission of SH U 508A ultrasound contrast agent and color or power Doppler sonography. Invest Radiol 2000;35:253–259. To assess the vascularization of neuroendocrine tumors by stimulated acoustic emission (SAE) of SH U 508A during the blood pool phase in comparison with contrast-enhanced Doppler sonography. Thirty-six patients with neuroendocrine tumors received contrast-enhanced Doppler sonography and 21, an additional SAE. To classify tumor perfusion on Doppler sonography, a 4-step rating score was introduced: (1) no vessels (hypoperfusion); (2) one feeding or central vessel (hypoperfusion); (3) some vessels (hyperperfusion); and (4) disseminated vessels (hyperperfusion). In 36 patients, 1 pancreatic primary tumor, 33 liver metastases, 1 splenic metastasis, and 1 lymph node metastasis were examined. Results were correlated with biphasic spiral CT (n = 35) and angiography (n = 2). Arterial-phase CT and digital subtraction angiography revealed 18 hyper- and 18 hypoperfused lesions. Contrast-enhanced Doppler correctly classified 15 of 18 patients (83%) with hyperperfused lesions as well as 16 of 18 (89%) hypoperfused tumors by applying the rating score. SAE correctly identified 4 of 9 hyperperfused lesions (44%), 2 were isoperfused compared with normal liver tissue (22%), and 3 were hypoperfused (33%). Of 12 hypoperfused lesions, 11 were classified correctly (92%), and 1 showed isoperfusion. Hence, the positive and negative predictive values for SAE were 80% and 69%, respectively. For contrast-enhanced Doppler sonography, positive and negative predictive values were 88% and 84%, respectively. Blood pool SAE failed to determine subtle tumor perfusion correctly. The rating score for contrast-enhanced Doppler sonography characterized tumor perfusion with high accuracy. The use of a contrast agent significantly improved perfusion characterization.