Both systems are suitable for fine-needle biopsy and preoperative localization of lesions seen exclusively on MR images.

A guiding attachment is described that transforms a conventional magnetic resonance (MR) imaging surface coil into a stereotaxic biopsy unit. Eight patients, aged 38-66 years (mean, 54 years), with suspect breast lesions detected exclusively at contrast material-enhanced MR imaging underwent MR-guided needle biopsy with this unit. Diagnostic material was successfully aspirated in all patients (four carcinomas, three fibroadenomas, and one intraductal hyperplasia), and the diagnosis was subsequently confirmed at surgical biopsy. This technique promises to increase the diagnostic specificity for lesions seen solely at MR imaging.

Breast biopsy and lesion localization were performed with gadolinium-enhanced magnetic resonance (MR) imaging guidance, with use of a stereotaxic biopsy system consisting of a flexible circular surface coil with an acrylic cylinder as an add-on guidance device. Twenty-five procedures (23 localizations, two core biopsies) were performed in lesions depicted at diagnostic MR imaging, without technical failure. The guidance system permitted easy, precise, and flexible biopsy and localization of all breast lesions.

In this note, the imaging properties of a CCD x-ray film scanner were investigated. The relationship between optical density and the logarithm of output pixel value provides information on the linearity of the system. The resolution properties of the scanner can be characterized by the presampling modulation transfer function which was calculated from a set of line spread functions with various alignments relative to the sampling grid. Our results show that the scanner is linear up to 2.0 optical density units, which leads to restrictions in digitizing x-ray films with higher optical density. The measured MTF shows the good spatial resolution of the CCD scanner which is demonstrated on an example.

A prototype compression device for a bilateral breast surface coil was manufactured. It was tested in clinical practice (157 patients), and resultant images were compared with those obtained with simple ventral stuffing of the bottom of the coil (181 patients). Compression resulted in reduction of magnetic resonance (MR) examinations with severe motion artifacts from 20 (11%) of 181 examinations to three (2%) of 157 examinations (P = .001). Use of this compression device allowed the subtraction technique at MR imaging in the breast to become an effective method for ensuring more lesion conspicuity.