Complexity of Ultrasound and CT Fusion Examinations: Are They Feasible in the Daily Routine?

Objective: The purpose of this study is to determine whether ultrasound and CT image fusion, used for the assessment of upper abdominal organ lesions, can be successfully managed in a passable examination time and whether the method is feasible in the clinical daily routine.

Subjects And Methods: Fifty-four consecutive patients presenting with organ lesions on contrast-enhanced CT underwent ultrasound and CT fusion imaging the same day. Examination times per patient, per organ, and per lesion were registered, and the mean diameter of all lesions per examination was calculated. Initial automatic superimposition was followed by manual superimposition using up to three landmarks.

Results: A total of 199 lesions (mean, 3.7 lesions per patient) were assessed. Thirty-three examiniations yielded benign results, and seven examinations revealed malignant findings. In 14 patients a coexistence of both benign and malignant lesions was found. The mean examination time per patient was 11.5 minutes, the time per organ was 6.8 minutes, and the time per lesion was 4 minutes. The required time per organ (p < 0.001) and per lesion (p = 0.62) decreased when more organs were evaluated. The expenditure of time was higher when only malignant lesions were detected, compared with explicitly benign lesions (9.7 vs 6.7 minutes per organ, p = 0.84; 4.9 vs 4.1 minutes per lesion, p = 0.56). Lesions smaller than 10 mm required a longer examination time compared with lesions 10 mm and larger (7.6 vs 6.3 minutes per organ, p = 0.79; 4.5 vs 3.6 minutes per lesion, p = 0.35).

Conclusion: Ultrasound and CT fusion with the objective of lesion classification can be realized in an acceptable examination time and is recommended for elucidation of undetermined small lesions on contrast-enhanced CT, if they are not directly detected at unfused ultrasound.