title: 16-Detector multislice CT-skeletal scintigraphy image co-registration.
abstract: OBJECTIVE
  Co-registration of bone scintigrams with radiographs has been used in the diagnosis of wrist injuries, although co-registration of tomographic bone scintigraphy with computed tomography (CT) has not been widely reported. We describe a co-registration technique in patients with possible wrist fracture.
  
  
  METHODS
  The technique was used on three patients and involved placing the wrist on a Perspex board and tracing the outline of the forearm and hand with a pen to try and ensure accurate repositioning on the board for the two sets of imaging. Four point source markers were attached to the board during both examinations. Single photon emission computed tomography (SPECT) was performed 4 h after injection Tc-methylenediphosphonate (MDP), using a dual-headed gamma camera. CT images were acquired on a 16-detector CT unit. The SPECT and CT images were co-registered with commercially available image fusion software. The centre of the four markers was identified in both sets of images and a rigid body point match algorithm was used. Before patient studies, the technique was tested using a phantom.
  
  
  RESULTS
  In all the phantom and clinical studies it was possible to identify the positions of all the markers. There were varying degrees of success in patient repositioning.
  
  
  CONCLUSIONS
  We describe a technique that may aid the fusion of functional images from skeletal scintigraphy with the exquisite anatomical detail from the latest CT technology, in the detection of occult wrist fractures. The technique may aid fracture localization and/or detection and might help distinguish the clinically important scaphoid fractures from other benign carpal lesions.
authors.affiliation: Department of Radiology, Addenbrooke's Hospital, Cambridge, UK. drashleygroves@hotmail.com
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Groves
authors.forename: Nicholas
authors.initials: N
authors.lastname: Bird
authors.forename: Ian
authors.initials: I
authors.lastname: Tabor
authors.forename: Heok K
authors.initials: HK
authors.lastname: Cheow
authors.forename: Kottekkatu K
authors.initials: KK
authors.lastname: Balan
mesh_terms: D000465:Algorithms; D050723:Fractures, Bone / Q000000981:diagnostic imaging; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals; D013382:Subtraction Technique; D013669:Technetium Tc 99m Medronate / Q000031:analogs & derivatives*; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*; D014954:Wrist Injuries / Q000000981:diagnostic imaging*; D014955:Wrist Joint / Q000000981:diagnostic imaging
chemical_list: D019275:Radiopharmaceuticals; C024226:technetium Tc 99m hydroxymethylene diphosphonate; D013669:Technetium Tc 99m Medronate