Accuracy of contrast-enhanced harmonic EUS with a second-generation perflutren lipid microsphere contrast agent (with video)

Background: EUS-FNA has limitations in cancer diagnosis/staging. New contrast agents, transducers, and processors have improved the potential of contrast-enhanced harmonic (CEH)-EUS.

Objective: To determine optimal settings and preliminary accuracy of CEH-EUS by using a second-generation perflutren lipid microsphere contrast agent and a prototype linear echoendoscope.

Design: Prospective, comparative, pilot study.

Setting: Tertiary-care medical center.

Patients: This study involved patients with esophageal/pancreatic/liver tumors or adenopathy.

Intervention: Contrast agent was injected (10 μL/kg intravenously in 1-2 doses), and the mechanical index was optimized over 5 cases (0.3). Intermittent/continuous imaging was used with extended pure harmonic detection.

Main outcome measurements: Before-contrast and after-contrast predictions of neoplasia (5-point Likert scale). The reference standard was positive tissue or 6-month follow-up. Perfusion factors (sequence, pattern, washout) were noted, and phases were video recorded (arterial, venous, and postvenous).

Results: Thirty sites (7 nodes and 16 pancreatic and 7 nonpancreatic masses) were imaged in 21 patients; 21 of 30 had FNA, and 5 had surgery. Four cases (13.3%) were rated as undecided/indeterminate with EUS (vs 1 [3.3%] with CEH-EUS; P = .35). Twenty-four cases with confirmed diagnoses (12 malignant and 12 benign) were used for test performance: positive/negative predictive values for CEH-EUS were 80.0% (95% confidence interval, 51.9%-95.7%)/100.0% (95% confidence interval, 63.0%-100.0%) versus 84.6%/100.0% for EUS. Accuracies, counting "undecided" (1 in CEH-EUS and 4 in EUS) as incorrect, were 83.3% and 79.2%. In 2 cases, management would change significantly: (1) liver hemangioma, avoiding FNA; and (2) mediastinal "cyst" confirmed as solid.

Limitations: Small sample. Tissue not always available.

Conclusion: CEH-EUS adds minimal imaging time and is accurate, with small improvement over EUS. Added information in vascular and cystic lesions can potentially change management.