[Feasibility of magnetic resonance-guided fine-needle percutaneous biopsy]

Fluoroscopic, US, and CT guidance to aspiration cytology are valuable tools for oncologic diagnosis. MR imaging is now replacing CT as the imaging method of choice to guide biopsy mainly in the abdomen and pelvis. The standard needles used for CT-guided biopsy are unsuitable for MR guidance because ferromagnetic artifacts shade the underlying anatomy. A new needle specifically designed for MR guidance allowed MR-guided aspiration biopsies to be carried out in a group of 17 patients with different neoplastic diseases. To locate the lesion and to assess its depth, a glass pipette containing a diluted solution of paramagnetic contrast medium (Gd-DTPA) was placed on the skin surface. In 13/17 patients (76.5%), biopsy was successful and histology and/or cytology allowed a diagnosis to be made. In spite of their longer measurement times, T1-weighted SE images clearly demonstrated both needle and lesion. On the contrary, fast images (FLASH, 15 degrees-90 degrees), with/without breath holding, although much shorter (7 s), were often useless, due to artifacts, mainly in small lesions.