title: How MRI compatible is "MRI compatible"? A systematic comparison of artifacts caused by biopsy needles at 3.0 and 1.5 T.
abstract: OBJECTIVE
  This study was designed to systematically investigate artifacts caused by interventional needles recommended for use in MRI, with focus on field strength, needle/mandrin type, orientation and sequence.
  
  
  METHODS
  Eight different MRI compatible needles were placed in porcine tissue and examined at 1.5 and 3.0 T with balanced-steady-state-free-precession (B-SSFP) and T1-weighted-spoiled-gradient-echo (T1-SPGR) sequences in different orientations to B0. Artifact diameters with regards to the primary, inner, and secondary, outer artifacts were assessed and statistically evaluated.
  
  
  RESULTS
  The types and degree of artifacts varied considerably, especially between different mandrin types even for the same needles. Orientation of the needle in the magnetic field was another main contributor to the artifact dimensions. Less important factors were the type of pulse sequence and field strength. Artifacts ranged from 0.7 mm (steel, 0°, B-SSFP, 3.0 T, inner) to 71.4 mm (nitinol, 90°, B-SSFP, 1.5 T, outer). Inner artifact diameters in B-SSFP were slightly larger (8.2 ± 5.7 mm) than those in T1-SPGR (7.6 ± 5.4 mm) and comparable between 1.5 and 3.0 T (e.g., 8.0 vs. 8.4 mm, B-SSFP).
  
  
  CONCLUSIONS
  Although all were sold as "MR compatible," the artifacts differed greatly between needle types, and even more so for different mandrins. The results suggest an empirical approach to the needle choice based on lesion type and approach angle.
authors.affiliation: Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany. tpenzkofer@ukaachen.de.|Surgical Planning Lab, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA. tpenzkofer@ukaachen.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Penzkofer
authors.affiliation: Klinikum Osnabrück, Röntgen- und Strahlenklinik, Am Finkenhügel 1, 49076, Osnabrück, Germany.
authors.forename: Nilufar
authors.initials: N
authors.lastname: Peykan
authors.affiliation: Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Schmidt
authors.affiliation: Department of Radiology, Justus-Liebig University Gießen, Klinikstrasse 3, 35392, Giessen, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Krombach
authors.affiliation: Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Pauwelsstr. 30, Aachen, 52074, Germany.
authors.forename: Christiane K
authors.initials: CK
authors.lastname: Kuhl
mesh_terms: D000818:Animals; D016477:Artifacts; D001707:Biopsy, Needle / Q000295:instrumentation; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D009339:Needles; D019047:Phantoms, Imaging; D013552:Swine