Factors That Impact the Duration of MRI-Guided Core Needle Biopsy

Abstract

The purpose of our study was to determine which patient-related, target lesion-related, or procedure-related variables impact the duration of MRI-guided core needle breast biopsy. Between July 11, 2006, and September 26, 2007, data were collected for 75 single-target MRI-guided 9-gauge vacuum-assisted core needle biopsy procedures using a grid-guidance technique and performed at a single institution. The following variables were studied: MRI suite occupation time, number of operators, patient age and breast size, target morphology and location, approach to target, equipment used, number of image acquisitions and times the patient was moved in and out of the closed magnet, and occurrence of complications. Statistical analysis was performed using the Student's t test, analysis of variance, and Pearson's correlation, with p values < 0.05 considered significant. The mean duration was 57.9 minutes (SD, 17.2 minutes; range, 30-109 minutes). None of the patient- or target-related variables significantly impacted the duration, although lesions located in the anterior third of the breast showed a trend to prolong the procedure (p = 0.059). The time to complete a procedure was reduced when the operating radiologist was assisted by a breast imaging fellow-in-training (p = 0.01). Increasing numbers of image acquisitions and times the patient was moved in and out of the magnet significantly lengthened the procedure duration (p = 0.0001 for both). No major complications occurred. Biopsies yielded 16% (12/75) malignant and 84% (63/75) benign diagnoses. Variables that minimized procedure duration were number of image acquisitions, number of patient insertions or removals from the magnet, and assistance of a breast imaging fellow-in-training. No patient-related or target-related variables impacted procedure time.