title: Automatic passive tracking of an endorectal prostate biopsy device using phase-only cross-correlation.
abstract: MR-guided transrectal prostate biopsy is currently a time-consuming procedure because the imaging slice is often manually realigned with the biopsy needle during lesion targeting. In this work a pulse sequence is presented that automatically follows a passive marker attached to a dedicated MR biopsy device holder, thus providing an alternative to existing active tracking methods. In two orthogonal tracking FLASH images of the marker the position of the needle axis is automatically identified using a phase-only cross-correlation (POCC) algorithm. The position information is then used to realign a trueFISP imaging slice in real time. In phantom experiments the sensitivity of this technique to initial misalignments of the marker and to the signal-to-noise ratio was evaluated. In several puncture experiments the precision of the needle placement was analyzed. The POCC algorithm allowed for a precise identification of the marker in the images even under severe initial misalignments of up to 45 degrees. At a frame rate 1 image/s a precision of the needle placement of 1.5 +/- 1.1 mm could be achieved.
authors.affiliation: Deutsches Krebsforschungszentrum, Abteilung Medizinische Physik in der Radiologie, Im Neuenheimer Feld 280, Heidelberg, Germany.
authors.forename: André
authors.initials: A
authors.lastname: de Oliveira
authors.forename: Jaane
authors.initials: J
authors.lastname: Rauschenberg
authors.forename: Dirk
authors.initials: D
authors.lastname: Beyersdorff
authors.forename: Wolfhard
authors.initials: W
authors.lastname: Semmler
authors.forename: Michael
authors.initials: M
authors.lastname: Bock
mesh_terms: D000465:Algorithms; D001706:Biopsy / Q000295:instrumentation*; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D019047:Phantoms, Imaging; D011467:Prostate / Q000473:pathology*; D012007:Rectum