Background: We examined contrast-enhanced harmonic grayscale sonographic findings of pancreatic carcinoma in relation to the pathological findings in resected specimens to evaluate correlations between observations made by this modality and the pathological findings. Methods: The pathological findings of surgical specimens obtained from 16 patients were examined in relation to the contrast-enhanced harmonic gray-scale sonography findings. Lesion vascularity was examined by contrast- enhanced harmonic gray-scale sonography from 20 to 50s after the injection of Levovist (Schering, Berlin, Germany)- (early phase), and lesion enhancement was also monitored at approximately 90s after injection (delayed phase). Results: Contrast-enhanced harmonic gray-scale sonography showed positive enhancement in 12 of the 16 lesions (peripheral tumor region alone, n = 9; entire tumor, n = 3), while the other 4 lesions showed no contrast enhancement in any region. Twelve enhanced regions (9 peripheral tumor region and 3 entire tumor regions) detected by contrast-enhanced harmonic gray-scale sonography showed: (1) mild fibrosis with inflammation, in 10 regions (83% ); (2) the presence of both carcinoma cells and residual acinar cells in 8 (67% ); and (3) presence of relatively large arteries in 2 (17% ). In contrast, 13 non-enhanced regions (4 entire tumor regions and 9 central regions) showed: (1) severe fibrosis in 10 regions (77% ); (2) necrosis in 7 (54% ); and (3)- mucin in 4 (31% ). Conclusions: Contrast-enhanced harmonic gray-scale sonographic findings of pancreatic carcinoma are influenced by interstitial histological features associated with tumor growth. Background: We examined contrast-enhanced harmonic grayscale sonographic findings of pancreatic carcinoma in relation to the pathological findings in resected specimens to evaluate correlations between observations made by this modality and the pathological findings. Methods: The pathological findings of surgical specimens obtained from 16 patients were examined in relation to the contrast-enhanced harmonic gray-scale sonography findings. Lesion vascularity was examined by contrast-enhanced harmonic gray-scale sonography from 20 to 50s after the injection of Levovist (Schering, Berlin, Germany) Results: Contrast-enhanced harmonic gray-scale sonography showed positive enhancement in 12 of the 16 lesions (peripheral tumor region alone, n = 9; entire tumor, n = 3), while the other 4 lesions showed no contrast enhancement in any region. Twelve enhanced regions (9 peripheral tumo r region and 3 entire tumor regions) detected by contrast-enhanced harmonic gray-scale sonography showed: (1) mild fibrosis with inflammation, in 10 regions (83%); (2) the presence of both carcinoma cells and residual acinar cells in In contrast, 13 non-enhanced regions (4 entire tumor regions and 9 central regions) showed: (1) severe fibrosis in 10 regions (77%); (2) necrosis in 7 (54%); and (3) - mucin in 4 (31%). Conclusions: Contrast-enhanced harmonic gray-scale sonographic findings of pancreatic carcinoma are confirmed by interstitial histological features associated with tumor growth.