title: Unclear focal liver lesions in contrast-enhanced ultrasonography--lessons to be learned from the DEGUM multicenter study for the characterization of liver tumors.
abstract: OBJECTIVE
  To discuss the difficulties of contrast-enhanced ultrasound (CEUS) in a large multi-center trial.
  
  
  METHODS
  CEUS was performed on 1349 liver lesions with an unclear diagnosis after native ultrasound using a standardized protocol (phase inversion; low MI < 0.4; Sonovue Bolus 1.2 - 4.8 ml). The early arterial, arterial, portal venous and late phase > 2 min. were documented. The diagnosis based on CEUS results was compared to the final diagnosis (histology: n = 1006; MRI: n = 269; CT: n = 269 - multiple examinations possible).
  
  
  RESULTS
  Of the 1349 enclosed liver lesions, 20 could not be definitively diagnosed even using all diagnostic steps including histology (the others were proven to be benign n = 573 or malignant n = 756). Of the 1349 unclear liver lesions, 1257 could be differentiated with an accuracy of 90.3% using CEUS. The sensitivity, specificity, and positive and negative predictive value for malignant liver lesions was 95.8%, 83.1%, 88.2% and 93.7% respectively. 92 liver lesions (6.8%) could not be definitively diagnosed using CEUS. Most of them were benign (n = 67) on final diagnosis. The CEUS diagnosis was wrong for 39 lesions. However, only 8 lesions classified as benign by CEUS turned out to be malignant. In 3 cases HCC proven by histology was incorrectly diagnosed by CEUS as adenoma and 2 lesions incorrectly diagnosed by CEUS as FNH turned out to be an HCC and a metastasis. Two lesions diagnosed by CEUS as hemangiomas turned out to be an HCC and a metastasis. One lesion classified as benign by CEUS was ultimately diagnosed as a lymphoma.
  
  
  CONCLUSIONS
  Even in this multi-center trial, CEUS proved to be an excellent method for clarifying liver lesions remaining unclear after native ultrasound. The CEUS diagnosis of benign was only incorrect in a few cases.
authors.affiliation: Department of Medicine 1, Universitiy Erlangen-Nuremberg, Germany. thomas.bernatik@uk-erlangen.de
authors.forename: T
authors.initials: T
authors.lastname: Bernatik
authors.forename: K
authors.initials: K
authors.lastname: Seitz
authors.forename: W
authors.initials: W
authors.lastname: Blank
authors.forename: A
authors.initials: A
authors.lastname: Schuler
authors.forename: C F
authors.initials: CF
authors.lastname: Dietrich
authors.forename: D
authors.initials: D
authors.lastname: Strobel
mesh_terms: D001706:Biopsy; D044963:Biopsy, Fine-Needle; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D020518:Focal Nodular Hyperplasia / Q000000981:diagnostic imaging / Q000473:pathology; D006391:Hemangioma / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008107:Liver Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary; D010743:Phospholipids; D012039:Regional Blood Flow / Q000502:physiology; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride